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11862934 | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In one preferred form of the invention, and looking now atFIGS.1-10, there is provided a widely tunable, single mode emission semiconductor laser5which comprises a semiconductor substrate10with an epitaxy that allows for semiconductor laser operation, e.g., as a laser diode or as a cascade laser. By way of example but not limitation, semiconductor substrate10may comprise a III/V semiconductor material such as gallium nitride (GaN), gallium arsenide (GaAs), indium phosphide (InP) or gallium antimonide (GaSb), depending on the target wavelength range of the laser. The epitaxy generally comprises a layer structure that contains an active zone with one or more quantum films, upper and lower cladding, and upper and lower waveguide layers. More particularly, the widely tunable, single mode emission semiconductor laser5has a cuboid shape with the bottom formed by semiconductor substrate10and the top formed by an upper waveguide layer which is structured so as to provide two linearly-aligned ridge waveguides15,20that are aligned in a straight line perpendicular to the four facets25,30,35,40, with facets25,30forming the front and rear facets for linear ridge waveguide15and facets35,40forming the front and rear facets for linear ridge waveguide20. The two linear ridge waveguides15,20preferably have a width and height that are comparable to the target wavelengths, and the two linear ridge waveguides15,20are preferably spaced from one another by a distance D which is about one-half the target wavelength. The two linear ridge waveguides15,20are structured such that they guide the laser mode to the four facets25,30,35,40. The two linear ridge waveguides15,20define two coupled cavities45,50, respectively, with coupled cavity45comprising facets25,30, and with coupled cavity50comprising facets35,40. A gap55separates the two coupled cavities45,50. The two linear ridge waveguides15,20are preferably generated through a material removal process effected from the top (such as chemical or physical etching). The remaining material (i.e., the material remaining after etching) then defines the two linear ridge waveguides15,20. The lengths of the coupled cavities45,50are typically defined through a second material removal process, typically etching, such that facets25,30,35,40, as well as the gap55between the two linear ridge waveguides15,20, are defined with a precision on the order of 10 nanometers. The typical length of the two coupled cavities45,50is between from about 80 nm to about 800 nm. It is also possible to structure Distributed Bragg Reflectors (DBRs) on facets25,30,35,40to control the reflectivity of the facets and gap55beyond the values that are obtainable with a single etching step. Two heating resistors60,65are structured in close proximity to the sides of the two linear ridge waveguides15,20, i.e., heating resistor60extends along linear ridge waveguide15and heating resistor65extends along linear ridge waveguide20. The distance is typically one or a few micrometers (note: this refers to the lateral distance between the linear ridge waveguides15,20and the heating resistors60,65, respectively—ideally one would like these to be as close as possible, but the minimum distance is limited by the fact that one needs to isolate the heating resistors60,65from the laser contacts (i.e., p-contacts70,75, respectively, see below), therefore a distance of a few, e.g., two, micrometers, is necessary). The two heating resistors60,65are typically processed from a highly conducting material (e.g., titanium (Ti), platinum (Pt), or gold (Au)) and their dimensions are arranged such that the total resistance is on the order of a few Ohms. It is particularly preferred that the heating resistors60,65possess a “meandering” structure, which enhances the heat contact between the two linear ridge waveguides15,20and the two heating resistors60,65, respectively, at constant resistivity (see, for example,FIG.11, which schematically illustrates the aforementioned “meandering” structure). The laser5comprises two p-contacts70,75for receiving the laser currents on the tops of the two linear ridge waveguides15,20, i.e., p-contact70extends along linear ridge waveguide15and p-contact75extends along linear ridge waveguide20. The two p-contacts70,75are typically processed with a highly conductive material, e.g., gold (Au), and linked to two laser current contact pads80,85, respectively (i.e., contact pad80is connected to the p-contact70for linear ridge waveguide15and contact pad85is connected to the p-contact75for linear ridge waveguide20). The two laser current contact pads80,85are positioned on the opposite side of laser5to the two heating resistors60,65. The two n-contacts86,87for the two coupled cavities45,50are processed on the bottom of the chip (i.e., at the bottom of semiconductor substrate10, seeFIG.7) in a manner which will be appreciated by those skilled in the art in view of the present disclosure. By way of example but not limitation, in one preferred form of the invention, the two n-contacts are a single, shared n-contact—it is simply the bottom of the chip that is soldered onto the heat spreader (see heat spreader105, below, with its integrated heating resistor110, also below). The individual currents are injected through the p-contacts70,75and do not widen before passing through the active layer (i.e., the gain media in linear ridge waveguides15,20) due to dimensions and relatively low lateral conductivity. The two heating resistors60,65are provided with their own contact pads, preferably on the side opposite to the laser current contact pads80,85, and the two heating resistors60,65may share a common ground contact pad. By way of example but not limitation, three heating resistor contact pads90,95,100may be provided, with contact pad95being a common ground contact pad, so that contact pads90,95are used to supply current to heating resistor60, and contact pads100,95are used to supply current to heating resistor65. The semiconductor substrate10of the laser5is preferably mounted on a heat spreader plate105that contains a heating resistor110for heating the bulk of semiconductor substrate10. Contact pads115,120are used to supply electrical current to heating resistor110. If desired, contact pads125,130,135,140,145may be provided on heat spreader105, with the contact pads providing easy electrical connection to various components of semiconductor laser5, e.g., various ones of contact pads125,130,135,140,145may be connected to various ones of contact pad80for p-contact70of coupled cavity45, contact pad85for p-contact75of coupled cavity50, contact pad90for heating resistor60, contact pad95(the common ground) for heating resistors60,65, and contact pad100for heating resistor65, whereby to provide easy electrical connection to these components. Note that the various contact pads do not require a particular bonding scheme, and may be adjusted according to a particular application. However, it is generally preferred that the common ground for the heating resistors60,65is bonded to the ground for the chip heating resistor110. In other words, it is generally preferred that contact pad120(the ground) of chip heating resistor110is connected to contact pad140for the common ground95for heating resistors60,65. Thus it will be seen that, in the preferred embodiment of the present invention, there is provided a semiconductor laser5which comprises a semiconductor substrate10, a first linear ridge waveguide15which forms a first coupled cavity45, and a second linear ridge waveguide20which forms a second coupled cavity50, with first coupled cavity45being separated from second coupled cavity50by a gap55. Coupled cavities45,50comprise p-contacts70,75and n-contacts (not shown, and preferably in the form of a common n-contact) for allowing laser currents I1, I2to be injected into coupled cavities45,50, respectively. Coupled cavities45,50also comprise heating resistors60,65, respectively, for heating the coupled cavities when heating currents H1, H2are applied to heating resistors60,65, respectively. A heating resistor110is provided for heating the semiconductor substrate10of laser5so as to regulate the base temperature T of the chip (i.e., semiconductor substrate10). The foregoing construction provides semiconductor laser5with five “controls” which may be used to regulate the output wavelength of laser5, i.e., the base temperature T of the chip (which is controlled by current passed through heating resistor110), the laser currents I1, I2which are injected through the two coupled cavities45,50(i.e., by means of the p-contacts and n-contacts for the two coupled cavities), and the heating currents H1, H2which are applied to the two coupled cavities through the adjacent heating resistors60,65. In essence, in the preferred embodiment of the present invention, semiconductor laser5comprises two coupled cavities45,50which are heated by heating resistors60,65, respectively. One of the coupled cavities45,50possesses a length that ensures that the distance between two of its Fabry-Perot modes is smaller than the tuning range. This is typically the shorter cavity (i.e., cavity50in the construction shown inFIGS.1-10). The longer cavity (i.e., cavity45in the construction shown inFIGS.1-10) may be several times longer than the shorter cavity50. The two heating resistors60,65are preferred to have a resistance on the order of 1-20 Ohms. This ensures that the cavities can be heated at voltages less than 10 Volts and at currents less than 500 Milliampere. Semiconductor laser5is constructed on a semiconductor substrate10which has its own heater110. In the preferred form of the invention, the semiconductor laser5is disposed (e.g., soldered) on a heat spreader105. The preferred mode of operation of the laser is to characterize the laser according to Eq. 2. Each shape of the base mode possesses a distinct base wavelength λi. Then a combination of the heater currents H1, H2can be tuned to sweep a range of the wavelengths. Thereafter, the base temperature T of the laser is adjusted by changing the current of the heater which heats the semiconductor substrate (i.e., the chip). This shifts the gain maximum. The laser currents I1, I2are then adjusted to achieve the desired light output level; this is necessary since the laser efficiency depends critically on the base temperature T of the chip (i.e., semiconductor substrate10). The ratio between the two laser currents I1, I2is then adjusted to achieve an optimal side mode suppression ratio. Then another sweep may be performed, e.g., by varying the combination of heater currents H1, H2. This process may be repeated until the entire gain of the laser material is covered. The advantage of fixing the base temperature T and then performing another sweep is that this tuning process is very fast, since the slowest part in tuning is achieving a change in the base temperature T of the chip (i.e., semiconductor substrate10). Additional Information on the Characterization of the Semiconductor Laser 1. Background There exists a plethora of possibilities for the construction of widely tunable semiconductor lasers that are able to achieve stable single mode operation over a wide range of wavelengths. The requirement that these lasers are suitable for series production sets imposes a number of constraints, in particular:1. Established process: There has to be an established process route that allows for high reproducibility and minimal process variation.2. Monolithic device: It is highly advantageous to produce a monolithic device in which the laser consists of one singe semiconductor chip. This avoids costly and fragile alignment steps during production.3. Fully electronic control: It is highly desirable for field applications that the tuning is achieved through purely electronic control, which allows for applications with relatively low cost control electronics.4. Simple characterization: Widely tunable lasers possess high dimensional parameter spaces (base temperature and various laser and further control currents). The direct characterization of a high dimensional parameter space is unfeasible; e.g., a five dimensional parameter space scanned at a resolution of one percent in each parameter requires characterization of the laser at 10 billion operation points. It is therefore essential for series production that one has an effective model of the laser at ones disposal which is described by only a few parameters and that these parameters can be measured easily and with sufficient precision. 2. Effective Model Inspection of the equilibrium states reveals that in a given laser they depend only on a small set of specific combinations of certain macroscopically accessible quantities. These quantities are the center koand width Δk of the gain of the laser material, as well as the effective refractive indices niof the cavity segments. These quantities are in turn functions that depend essentially only on the base temperature T of the laser chip as well as the laser Iiand heater Hicurrent levels of the laser segments, i.e., ko(T,I1, . . . ,In) andni(T,I1, . . . ,In), while Δk is practically constant. A sufficiently good model for the gain maximum is ko=koo+aoT+∑i(boiIi+ci(Hoi)2),(1) while it is practically sufficient to assume that the gain width Δk remains constant. The effective refractive indices of the laser segments can be described by ni=nio+aiT+biIi+ciHi2, (2) while the effective refractive index of the gap is described by ng=ngo+aoT+∑i(bgiIi+ci(Hgi)2).(3) The effective model of the laser then consists of investigating which light modes, labelled by their vacuum wave number k=2πλ of the laser minimize the mirror losses, while lying within ±Δκ2 from the gain maximum ko. The modes that minimize the mirror losses are the so-called Fabry-Perot modes. These are standing waves whose modulus of the electric field possess minima at both laser facets. These modes are exponentially amplified through stimulated emission in the gain material with an effective exponent that is given by the average number of gain length lg that a single photon in the mode is reflected between the cavities. SeeFIG.12. It is important for the calculation of the laser spectra to take into account that the combination of gap and one of the laser segments can be viewed as an optical element that facilitates coherent tunneling through one of the laser facets. This coherent tunneling possesses a periodic dependence on the vacuum wave number of the mode, and thus is wavelength dependent.FIG.13shows schematically the transmission of the right facet for a right moving mode. An analogous picture exists for the left moving mode on the left facet. It is a particular advantage of the present design that these two reflectivities are the same for the left-moving and right-moving components of the Fabry-Perot modes, due to the periodicity of the Fourier transform. This reduces the amount of characterization necessary to understand the Vernier points of the laser. The product of the reflectivities of the two facets allows one to calculate the effective number of gain lengths that a photon remains in the laser, which in turn is the amplification exponent of the mode. Only the modes with the largest amplification exponents will appear within the spectrum of the laser. This connects the model parameters with spectra of the laser at an operation point. It is important to notice that one possesses an analytic expression for the wavelength dependence of the reflectivities of the two facets and that the reflectivity of each facet is well approximated by a periodic function of the wave number. 3. Characterization The identification of the modes with the highest reflectivities as the modes that appear in the spectra of the laser allows one to characterize the laser effectively by measuring a few spectra. It is fairly simple to identify the tuning of the entire cavity by considering the side mode spectrum of a laser. The Fabry-Perot modes of the entire laser appear as side modes of the coupled cavity laser. The vacuum wave number of the Fabry Perot modes is kn=2n(λ)λ.(4) These modes are seen as the main and side modes (modes with signal above −50 dB) inFIG.13. Using n(k)=n(ko)=dm/dk(ko)(k−ko), one sees that the distance between side modes is given by twice the length of the laser divided by the group index. One can easily measure the tuning parameters by measuring series in which one varies one of the laser parameters at a time. The tuning of the main mode (red/black) and the side modes (grey scale) is shown inFIG.14as the laser current of the short laser segment (i.e., linear ridge waveguide20) is varied from 23 mA to 45 mA, while the other control parameters are held fixed. The slope of this curve determines the tuning coefficient b2for the current I2in Eq. 2 (in the example ofFIG.14, the tuning coefficient b2possesses a slope of the main mode and of the side modes of about 0.11 nm/mA). This slope represents the tuning parameter of the entire optical length through current tuning. An analogous tuning can be measured when varying the laser current through the long laser segment (i.e., linear ridge waveguide15), thus measuring the tuning parameter b1(for the current I1in Eq. 2) of the long laser segment. Another important piece of information that can be read directly fromFIGS.13and14: the intensity of the side modes within the gain region exhibits a periodic modulation. This period is about 17 nm inFIG.14and it can be observed that the tuning of the side modes is slower than the tuning of the main modes. This is the resonant transmission effect of the optical length of the short cavity (i.e., linear ridge waveguide20). The main mode is seen to be the mode that lies at the maximum of the periodic reflectivity function of the short cavity (i.e., linear ridge waveguide20), whose maximum crosses the main mode at around 41 mA. This is a Vernier point, i.e., a point where the combined reflectivities of both mirrors achieve a maximum. Using the periodicity of the reflectivity and the tuning parameters, we can now predict a large number of Vernier points. The measurement of the tuning of the heater currents H1and H2for the linear ridge waveguides15and20, respectively, is analogous to the measurement of the laser currents I1and I2.FIG.15depicts the tuning of the laser with variations in the heater current of the shorter linear ridge waveguide20, with only the main side modes drawn. It can be clearly seen that the tuning is quadratic with the heater current, as one expects, since the heat produced by a heater scales quadratically with the current applied to the heater and the tuning scales linearly with the temperature change produced by the deposited heat. This allows one to determine the tuning parameters c1and c2for the heater currents H1and H2in Eq. 2. The final piece of information that one needs to characterize the laser is to determine its gain tuning. This can be achieved by taking a temperature series.FIG.16depicts tuning of the laser using variations in the base temperature of the laser (i.e., by varying the current applied to heating resistor110), where only the main side modes are drawn. It can be clearly seen from the lines formed by the side modes that the optical tuning of the effective cavity length (i.e., the combined lengths of linear ridge waveguide15and linear ridge waveguide20) scales linearly with temperature. Moreover, one can read off the tuning of the center of the gain of the laser by considering how the center of the main modes, depicted in orange or red, lies on a line with a steeper slope. One sees that the optical tuning is about 0.2 nm/K while the gain tuning is about 14 nm/K. In this way, one can determine the tuning parameter a for the variable T in Eq. 2. 4. Characterization of a New Laser Design Vs. Characterization of Mass Produced Lasers of the Same Design It should be appreciated that there is typically a difference between the characterization of a new laser design and the characterization of mass produced lasers of the same design. A new laser design typically requires a detailed characterization, because one has to understand how process variations and material properties transform into the effective model parameters. However, once the process variations of a particular design and process route are understood and lasers of the same design are mass produced, one has a much simpler characterization problem. In this case one only needs to measure the “fine tuning”. The simple laser characterization can then be reduced to an even shorter program (but of the same type as the program described above) which only measures a few properties of the laser to find the tuning parameters and locations of the base wavelengths with sufficient precision. Alternative Constructions and Modes of Operation In alternative constructions, one can consider lasers with more than two coupled cavities, lasers that possess only one heater at a coupled cavity, and lasers with several coupled cavities that possess heaters at each cavity or at only a subset of the cavities. The important part of the design is that the mode equation for the light mode possesses a scaling symmetry, such that a simple formula, analogous to that of Eq. 2, effectively describes the tuning behavior of the laser. In alternative modes of operation, the operating mode may be adjusted due to the needs of the application. In particular, it may be desired to only scan a discrete set of wavelengths rather than to perform a number of wavelength sweeps. Modifications of the Preferred Embodiments It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention. | 22,097 |
11862935 | DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or similar reference numerals denote the same or similar elements and therefore repeated description thereof will be omitted in some cases. In the following description, specific numerical values or material names will be exemplified, but the present invention is not limited thereto. It is obvious that different numerical values or materials can be used. Operation Principle of Wavelength-Tunable DBR Laser An operation principle of a wavelength-tunable DBR laser will be described.FIG.1is a schematic view illustrating a cross-sectional structure of a general DBR laser100. The DBR laser100includes an active region10that obtains an optical gain by injecting a current and DBR regions20aand20bprovided at both ends of the active region10in an optical axis direction. The active region10includes, on a substrate102, an active layer104that includes vertical confinement layers, a clad110, and an electrode112. The front DBR region20aincludes, on the substrate102, a DBR core layer106a, a diffraction grating108a, the clad110, and an electrode114a. The rear DBR region20bincludes, on the substrate102, a DBR core layer106b, a diffraction grating108b, the clad110, and an electrode114b.FIG.1illustrates anti-reflection coatings (AR coats)116aand116bprovided on end surfaces of the DBR laser100. FIG.2is a diagram illustrating a reflection spectrum of the front DBR region20aand the rear DBR region20bin the DBR laser100that has the configuration illustrated inFIG.1. A solid line indicates a reflection spectrum of the front DBR region20aand a broken line indicates a reflection spectrum of the rear DBR region20b. As shown in the spectrum ofFIG.2, a DBR serves as a mirror that selectively reflects a specific wavelength centering on a Bragg wavelength λBraggdetermined in accordance with a diffraction grating period. Because the Bragg wavelength is determined in accordance with the diffraction grating period and the front DBR region20aand the rear DBR region20bnormally have the same diffraction grating period, Bragg wavelengths are the same. Accordingly, only wavelengths in both front and rear DBR reflection bands are selectively confined in a resonator, and an amplification effect is obtained in the active region10to oscillate. When the wavelength confined in the resonator is sufficiently narrow due to the front DBR region20aand the rear DBR region20b, oscillation is performed in a single mode. By adjusting reflectance of at least one of the front DBR region20aand the rear DBR region20b, it is possible to adjust an optical output from the end surface of the front DBR region20aand the end surface of the rear DBR region20b. That is, as illustrated inFIG.2, by realizing a design in which the reflectance (indicated by the solid line) of the front DBR region20ais less than the reflectance (indicated by the broken line) of the rear DBR region20b, it is possible to inhibit an optical output from the end surface of the rear DBR region20band increase an optical output from the end surface of the front DBR region20a. The structures of the diffraction grating of the front DBR region20aand the rear DBR region20bare generally the same, but the reflectance of the DBR region can be adjusted in accordance with the length of the DBR region. A Bragg wavelength of the DBR region is expressed by λBragg=2neqA. Here, Λ indicates a diffraction grating period and neqindicates an equivalent refractive index. An oscillation wavelength of a DBR laser can be changed by changing the equivalent refractive index neqof the DBR region in a certain method. To change the oscillation wavelength while maintaining the oscillation of the DBR laser, the oscillation wavelength is adjusted by changing the Bragg wavelengths of both regions simultaneously while keeping the Bragg wavelengths of the front DBR region20aand the rear DBR region20bmatched. In general, as a modulation scheme for a refractive index, a method of controlling a temperature or a method of using a carrier plasma effect generated by injecting a current is used. As a wavelength-tunable laser using the carrier plasma effect, a DBR laser with a wavelength of 1.5 μm in which an INGaAsP/InP-based material is used has been widely reported so far (for example, see Non Patent Literature 1). Further, a wavelength-tunable DBR laser in which a wavelength-tunable width is broadened considerably by adopting a special diffraction grating structure such as a sampled grating (SG) or a super structure grating (SSG) to a DBR region has been reported (for example, see Non Patent Literature 2). Wavelength Change Amount by Carrier Plasma Effect A general wavelength-tunable DBR laser modulates an oscillation wavelength by decreasing a refractive index by a carrier plasma effect when a carrier density is increased by injecting a current into a DBR region, as described above. The wavelength change amount by the carrier plasma effect is expressed by the following expression. Math.1Δn=e2λ28π2c2ɛ0n(ΔNme+ΔPmh)(Expression1) Here, n indicates a core refractive index, e indicates an elementary charge, ε0indicates vacuum permittivity, c indicates the speed of light, ΔN and ΔP indicate densities of electrons and holes, respectively, and meand mhindicate effective masses of electrons and holes, respectively. As apparent from the above expression, by injecting a current and changing the densities of electrons and holes, the refractive indexes can be changed by the carrier plasma effect. Here, in consideration of the effective mass of holes that is about 10 times the effective mass of electrons, it is important, in a change amount of a refractive index, to change the density of electrons in a core layer. In a DBR laser with a 1.55 μm band, an InGaAsP-based material grating-matched with an InP substrate is used for the core layer of the DBR region. When a 1.3 μm band-wavelength DBR laser is manufactured using this material, an effective mass of a semiconductor material of which the DBR region is formed can be used as an important parameter for determining a change amount of a refractive index. Here, problems with a 1.3 μm-band wavelength-tunable DBR laser and causes of the problems will be described. A 1.3 μm-band wavelength-tunable DBR laser formed of an InGaAsP/InP-based material has problems that a change in a refractive index is less than that of a 1.55 μm-band wavelength-tunable DBR laser, and a sufficient wavelength-tunable amount cannot be obtained. As is apparent from Expression 1 of the carrier plasma effect described above, the change amount of the refractive index is reduced as the oscillation wavelength becomes shorter. Simply, when an oscillation wavelength becomes 1.3 μm from 1.55 μm, a change amount of the refractive index may decrease to about (1.3/1.55)2=0.7 times. One more cause is a reduction in a refractive index change resulting from an increase in the effective mass of InGaAsP in the core layer. For the core layer of the DBR laser, a material that has a small absorption loss with respect to oscillated light is used. That is, a composition is selected so that a bandgap wavelength of the core layer becomes a sufficiently short wavelength with respect to the oscillated light. In the case of a general DBR laser with a 1.55 μm band, InGaAsP having a bandgap wavelength of about 1.4 μm is used for the core layer of the DBR region. In the case of a 1.3 μm-band wavelength-tunable DBR laser, it is necessary to use InGaAsP having a bandgap wavelength of about 1.1 to 1.2 μm, which is sufficiently shorter than an oscillation wavelength of 1.3 μm, for the core layer of the DBR region. Here, the problem is that the effective mass metends to increase with a decrease in the bandgap wavelength of InGaAsP grating-matched with InP (for example, see Non Patent Literature 3). As is apparent from the expression of the carrier plasma effect described above, the increase in the effective mass of electrons in the material of the core layer is linked with a decrease in the change amount of the refractive index. In addition to this cause, in a case of manufacturing a 1.3 μm-band wavelength-tunable DBR laser in which InGaAsP with a bandgap wavelength of about 1.1 μm (1.1 Q) is used for a core layer, only the wavelength change amount equal to or less than half in that of a 1.55 μm-band wavelength-tunable DBR laser can be obtained. As described above, a change amount of a refractive index in a 1.3 μm-band wavelength-tunable DBR laser is less than that in a 1.55 μm-band wavelength-tunable DBR laser, and thus a sufficient wavelength-tunable amount cannot be obtained. In a general wavelength-tunable DBR laser in which InGaAsP/InP is used, even when the same carriers as those of a 1.55 μm-band wavelength-tunable DBR laser are injected, only a wavelength-tunable amount equal to or less than half can generally be obtained in a 1.3 μm-band wavelength-tunable DBR laser. Accordingly, to obtain a sufficient wavelength-tunable amount in a 1.3 μm-band wavelength-tunable DBR laser, it is effective to use a method of introducing a structure for confining many carriers in the core layer of the DBR region. Wavelength-Tunable DBR Laser According to the Embodiment As a carrier confinement structure according to an embodiment of the present invention, a carrier barrier layer in which a bandgap is greater than that in a clad layer is introduced in a boundary between the clad layer and the core layer of the DBR region. Further, a carrier barrier layer introduced in the boundary between a p-side clad layer and a core layer is doped in a p-type so as to have a carrier density greater than that in a p-type clad layer. Similarly, a carrier barrier layer introduced in the boundary between a n-clad layer and the core layer is doped in a n-type and designed to have a carrier density greater than that of a n-clad layer. As described above, it is more difficult to change a wavelength in a 1.3 μm-band wavelength-tunable DBR laser than in a 1.55 μm-band wavelength-tunable DBR laser. Therefore, it is necessary to increase the density of electrons by injecting more currents. However, there is a limit to an increase in the density of electrons and holes of the core layer by injecting a current. This is due to the fact that the density of electrons and holes does not increase because the electrons and holes overflow in p-side and n-side clad layers as a current is applied. FIG.3is a diagram schematically illustrating band structures of DBR regions. Focusing on the electrons in the band structure of a DBR region of the related art illustrated inFIG.3(a), the band on the conduction band side is flattened as a voltage is applied and carriers are injected into the core layer. However, with application of a voltage, electrons getting over a barrier of a boundary between the core layer and a p-side InP clad and overflowing to the p side increase, and thus the density of electrons does not increase. For holes on a valence electron band side, there is a limit to an increase in the density of holes for the same reason. As illustrated inFIG.3(b), in a band structure of a DBR region according to an embodiment of the present invention, a p-type carrier barrier layer is introduced between a core layer and a p-InP clad and an n-type carrier barrier layer is introduced between the core layer and the n-InP. The barrier layers have a composition with a larger bandgap than the clad layers and designed to have higher carrier density than the clad layers as p-type and n-type semiconductors by doping, and thus can be formed to have a high confinement effect in the core layer with respect to electrons and holes. In particular, for an InP-based material, the high effect can be obtained by using InAlAs as a material with a larger bandgap than InP. By introducing the barrier layers between the core layer and the p-InP clad and between the core layer and the n-InP, the carrier confinement effect in the core layer can be improved, and thus, a sufficient wavelength change amount can be realized in the 1.3 μm band. The wavelength-tunable DBR laser according to the embodiment is a wavelength-tunable DBR laser having an oscillation wavelength of 1.3 μm (for example, equal to or greater than 1.27 μm and equal to or less than 1.33 μm) in which an active region having an optical gain and a DBR region including a diffraction grating are integrated monolithically and an oscillation wavelength varies when a current is injected into the DBR region. A p-type doped electron barrier layer having a bandgap greater than that of a p-side clad layer is provided at the boundary between the p-side clad layer and a core layer in the DBR region. A n-type doped hole barrier layer having a bandgap greater than that of an n-side clad layer is provided at the boundary between the n-side clad layer and the core layer in the DBR region. The DBR core layer can be formed of, for example, InGaAsP or InGaAlAs. A bandgap wavelength of the DBR core layer is, for example, equal to or greater than 1.0 μm (1.0 Q) and equal to or less than 1.2 μm (1.2 Q). A diffraction grating of the DBR region may be a super structure grating (SSG). Example 1 FIG.4is a cross-sectional view of a wavelength-tunable DBR laser400according to Example 1. In the wavelength-tunable DBR laser400, the active region10in which an optical gain is produced by injecting a current, the DBR region40aand an SOA region50on the front side of the active region10in the optical axis direction, and a phase adjustment region30and the DBR region40bon the rear side of the active region10in the optical axis direction are integrated. The active region10includes, on an n-InP substrate402, a lower separated confinement heterostructure (SCH)416, an active layer418, an upper SCH420, a clad410, and an electrode412a. A length of the active region10in the optical axis direction is 250 μm. The SOA region50includes, on the n-InP substrate402the lower SCH416, the active layer418, the upper SCH420, the clad410, and an electrode412bas in the active region10. A length of the SOA region50in the optical axis direction is 300 μm. The front DBR region40aincludes, on the n-InP substrate402, a DBR core layer406a, a diffraction grating408a, a clad110, and an electrode414a. A length of the front DBR region40ain the optical axis direction is 200 μm. The rear DBR region40bincludes, on the substrate102, a DBR core layer406b, a diffraction grating408b, the clad110, and an electrode414bas in the front DBR region40a. A length of the rear DBR region40bin the optical axis direction is 500 μm. The phase adjustment region30includes the DBR core layer406b, the diffraction grating408b, the clad110, and the electrode414bon the substrate102as in the front DBR region40a. A length of the phase adjustment region in the optical axis direction is 100 μm. Next, a process of manufacturing the wavelength-tunable DBR laser400will be described. In element manufacturing, an initial substrate is used on which a lower SCH layer416, the active layer418of a multiple quantum well layer (MQW1), and an upper SCH layer420, in which InGaAsP is used, are sequentially grown on the n-InP substrate402. The multiple quantum well layer obtains an optical gain with respect to an oscillation wavelength of 1.3 μm band. First, portions (404aand404b) which become the active region10and the SOA region50of the wavelength-tunable DBR laser400are left, the upper SCH420, the active layer418, and the lower SH416of the other regions are electively etched to grow a semiconductor layer for the front DBR region40a, the phase adjustment region30, and the front DBR region40bby butt-joint regrowth. A layer structure of the DBR regions40aand40bhas an n-InP layer, an n-InAlAs layer, an i-InGaAsP (1.1 Q) layer, a p-InAlAs layer, and a p-InP layer from the side of the n-InP substrate402. The p-side InAlAs layer and the n-side InAlAs layer function as barrier layers for electrons and holes. (the n-InP layer, the n-side InAlAs layer, the i-InGaAsP (1.1 Q) layer, the p-side InAlAs layer, and the p-InP layer respectively correspond to the n-InP layer304, the n-side carrier barrier layer308, the InGaAsP302, the p-side carrier barrier layer310, and the p-InP306inFIG.3(b)). Further, both of the n-InAlAs layer and the i-InGaAsP layer are grating-matched with the n-InP layer. Both of the p-InAlAs layer and the i-InGaAsP layer are grating-matched with the p-InP layer. Here, for the p-side InAlAs, the effect of an electron barrier layer can be adjusted with impurity density thereof. For the n-side InAlAs, the effect of a hole barrier layer can be adjusted with impurity density thereof. In order to achieve a sufficient carrier confinement effect, the impurity density of 5×1017cm−3or more is necessary. When the impurity density of the p-InAlAs layer is small, in addition to a decrease in the effect of the electron barrier in a conduction band, a hole barrier may be formed between the p-InP clad and the core layer on the valence band side. The same applies to the n-InAlAs layer. Accordingly, a sufficient impurity density is necessary in the p-InAlAs that is a p-side barrier layer and the n-InAlAs that is an n-side barrier layer. In this example, doping is performed on both the p-type InAlAs and the n-type InAlAs so that carrier density becomes 1×1018cm−3. Subsequently, the uniform diffraction gratings408aand408boperating at the oscillation wavelength of 1.3 μm band are formed on the upper surfaces of the DBR core layer406aof the front DBR region40aand the DBR core layer406bof the rear DBR region40b. Thereafter, the p-InP clad layer410is grown on the entire element surface by regrowth. The thickness of the p-InP clad layer410is designed so that an optical field is not included in the electrode region. In this example, the thickness of the p-InP clad layer410is 2.0 μm. Further, a mesa structure extending in the optical axis direction is formed by etching and a semi-insulating InP layer in which both sides of a mesa structure have been doped with Fe is formed by re-embedding regrowth. Subsequently, p-side electrodes412a,412b,413,414a, and414bare formed on the upper surface of a semiconductor substrate. Thereafter, processes on a semiconductor wafer are completed by polishing the n-InP substrate402to 150 μm and forming electrodes (not illustrated) on the rear surface of the substrate. A waveguide structure according to this example has a buried hetero structure in which InP layers are formed on both sides of the mesa structure in the horizontal direction. A stripe width is set to 1.5 μm and an operation is performed at a single wavelength due to the diffraction gratings formed in the front DBR region40aand the rear DBR region40b. In the SOA region50, the core layer structure formed on the initial substrate remains as it is. The SOA region50has the same layer structure as the active region10of the wavelength-tunable DBR laser400. In addition, the front DBR region40a, the rear DBR region40b, and the phase adjustment region30have the same layer structure formed by the butt-joint growth, and the layer structure of these regions are different only in the presence or absence of the diffraction grating. As a result, the number of times the regions are regrown is reduced even in the structure in which multiple regions are integrated, and low cost manufacturing can be achieved. Operation feature evaluation of the manufactured wavelength-tunable DBR laser400is performed. An oscillation threshold of the DBR laser is about 25 mA under the condition of 25° C. An optical output of about 5 mW is obtained by injecting a current of 90 mA into the active region10and a current of 100 mA into the SOA region50in a state (an open state) in which a current is not applied to the DBR regions of the wavelength-tunable DBR laser400. Subsequently, wavelength-tunable feature evaluation of the manufactured element is performed. Here, to confirm an introduction effect of the InAlAs barrier layer, the wavelength-tunable DBR laser which does not include the InAlAs barrier layer is manufactured through the same processes. Here, a wavelength-tunable DBR laser that includes an InAlAs barrier layer is referred to as an element B and a wavelength-tunable DBR laser that does not include a comparison InAlAs barrier layer is referred to as an element A. In the element A, a layer structure of the front DBR region40aand the rear DBR region40bincludes an n-InP layer, an i-InGaAsP layer (1.1 Q), and a p-InP layer. The other element structure is the same as that of the above-described wavelength-tunable DBR laser400. For the wavelength-tunable feature evaluation, an oscillation wavelength spectrum is measured while adjusting an injection current amount in the DBR regions. Here, a current of 90 mA is injected into the active region10and a current of 100 mA is injected into the SOA region50. The current injection amounts for the front DBR region40aand the rear DBR region40bare adjusted to be proportional to region lengths. That is, a current Ifront injected into the front DBR region and a current Irear injected into the rear DBR region40bare adjusted to be proportional to Ifront/Irear=200/500. The phase adjustment region30is adjusted in a range of 0 to 10 mA so that a side-mode suppression ratio (SMSR) becomes maximum from the oscillation spectrum. A relation between a change amount of the oscillation wavelength and the current injection amount of the evaluated front DBR region40ais illustrated inFIG.5. InFIG.5, ▪ indicates the element A and ⋄ indicates the element B. As apparent from the wavelength-tunable feature of the element A illustrated inFIG.5, a wavelength-tunable amount considerably decreases compared to the DBR laser of a 1.55 μm band in the DBR laser of a 1.3 μm band, and the wavelength-tunable amount is saturated as about 2 nm. The wavelength changes is saturated with the current injection is due to the effect of heat generation due to the current injection. Since the refractive index of semiconductor materials increases as the temperature rises, the heat generation cancels the change in the refractive index due to the carrier plasma effect. In contrast, a wavelength-tunable amount of the element B can be about 4.5 nm which is substantially the same as that of the general 1.55 μm-band wavelength-tunable DBR laser. From the above results, it was confirmed that introduction of the barrier layer of InAlAs in DBR laser of 1.3 μm band has a high effect on improving the wavelength-tunable feature. Example 2 A wavelength-tunable DBR laser according to Example 2 is different from the wavelength-tunable DBR laser according to Example 1 in that InGaAlAs is adopted in the DBR core layers406aand406bof the DBR regions40aand40binstead of InGaAsP of the related art, and the other points are the same as those of the wavelength-tunable DBR laser according to Example 1. FIG.6is a diagram illustrating a case in which InGaAsP is used for the DBR core layer and a case in which InGaAlAs is used are schematically compared.FIG.6(a)illustrates a band structure when InGaAsP302is used for the DBR core layer andFIG.6(b)illustrates a band structure when InGaAlAs602is used for the DBR core layer. InFIG.6, the barrier layer is not illustrated to facilitate comparison of the boundary between the DBR core layer and the clad layer. As described above, to increase the wavelength-tunable amount by the carrier plasma effect, it is important to further increase the density of electrons than the density of holes. This is caused due to an effective mass of electrons which is about 10 times less than an effective mass of holes. When InGaAlAs is adopted in the DBR core layer, the electron confinement effect that electrons are confined in the DBR core layer can be further improved than in the InGaAsP layer. InFIG.6, a bandgap wavelength is set to 1.1 Q in both the DBR core layers of InGaAsP and InGaAlAs. As can be seen fromFIG.6, a conduction band barrier ΔEc with InP can generally be greater for InGaAlAs than InGaAsP. That is, with regard to electrons, a barrier between the InP clad and the DBR core layer is large, and thus a structure in which it is easy to confine electrons in the DBR core layer is formed. On the other hand, with regard to holes of a valence electron band, when InGaAlAs is adopted in the DBR core layer, the barrier between the InP clad and the DBR core layer becomes small compared to the InGaAsP layer, and thus the confinement effect decreases. However, because a contribution to a change in the refractive index of holes is less than a contribution to a change in the refractive index of electrons, an influence on the change in the refractive index is not large. A layer structure, each region length, and a manufacturing process of the active region10in the wavelength-tunable DBR laser according to this example are the same as those of the wavelength-tunable DBR laser according to Example 1 described above. An oscillation wavelength is also 1.3 μm. Only differences are that InGaAlAs is used for DBR core layers406aand406bof the front DBR region406aand the rear DBR region406b, and the layer structure of the DBR regions40aand40bhas an n-InP layer, an n-InAlAs layer, an i-InGaAlAs (1.1 Q) layer, a p-InAlAs layer, and a p-InP layer from the side of the n-InP substrate402. Here, both the InAlAs and InGaAlAs layers are grating-matched with InP. As in the case of Example 1, the p-side InAlAs layer and the n-side InAlAs layer function as barrier layers for electrons and holes, respectively. Wavelength-tunable feature evaluation of the manufactured wavelength-tunable DBR laser was performed. As in the case of Example 1, in the wavelength-tunable feature evaluation, an oscillation wavelength spectrum was measured while adjusting an injection current amount for the DBR regions40aand40b. Here, a current of 90 mA is injected into the active region10, and a current of 100 mA is injected into the SOA region50s. The current injection amounts for the front DBR region40aand the rear DBR region40bwere adjusted to be proportional to region lengths. Further, the phase adjustment region30was adjusted in a range of 0 to 10 mA so that an SMSR becomes maximum from the oscillation spectrum. The wavelength-tunable feature evaluated is illustrated inFIG.7. For comparison, the wavelength-tunable feature of the wavelength-tunable DBR laser (the element A) of the related art in which the InGaAsP layer described in Example 1 is included in the DBR core layers406aand406bof the DBR regions40aand40bis also illustrated. InFIG.7, ▪ indicates the element A and ⋄ indicates an element C which is the wavelength-tunable DBR laser according to this example. In the element C according to this example, the wavelength-tunable amount further increases than in the element B according to Example 1, and thus about 6 nm is obtained. A sufficient wavelength-tunable feature can be obtained as a general wavelength-tunable DBR laser. From this, the effect obtained by adopting the InGaAlAs layer in the DBR core layers406aand406bof the DBR regions40aand40bis confirmed. Example 3 A wavelength-tunable DBR laser according to Example 3 is different from the wavelength-tunable DBR laser according to Example 2 in that an SSG is adopted in the diffraction gratings408aand408bof the front DBR region40aand the rear DBR region40bof the wavelength-tunable DBR laser400described with reference toFIG.4. The others are the same as those of the wavelength-tunable DBR laser according to Example 2. In a general DBR laser, a uniform diffraction grating is adopted in a DBR region and one reflection band is used for a variation in a wavelength. In contrast, a plurality of reflection bands can also be added to the DBR region by a special diffraction grating structure called in a super structure grating in an SSG-DBR laser. Thus, it is possible to realize a broader wavelength-tunable width. FIG.8is a schematic diagram illustrating a reflection band of the DBR region in an SSG-DBR laser.FIG.8(a)schematically illustrates a reflection spectrum of the rear DBR region40b.FIG.8(b)schematically illustrates a reflection spectrum of the front DBR region40a.FIG.8(c)schematically illustrates a combined reflectance spectrum obtained by multiplying the reflection spectrum of the front DBR region40aby the reflection spectrum of the rear DBR region40b. As illustrated inFIG.8, the diffraction grating408awhich is the SSG of the front DBR region40aand the diffraction grating408bwhich is the SSG of the rear DBR region40bhave reflection spectra in which a plurality of reflection peaks are arranged at an equal interval. The reflection spectra of both the diffraction gratings408aand408bhave seven reflection peaks. InFIG.8, reflection peak intervals of the reflection spectra of the diffraction gratings408aand408bare indicated by Δλfrontand Δλrear, respectively. Here, Δλfrontis designed to be slightly greater than Δλrear. Due to a difference between the reflection peak intervals, a broad wavelength-tunable width can be realized with a single mode operation remaining in the SSG-DBR laser. This is because Δλfrontand Δλrearare slightly different, the reflection peaks of the reflection spectrum of the front DBR region and the reflection peaks of the reflection spectrum of the rear DBR region are completely matched at only one location, and therefore a combined reflection spectrum has one reflection peak. In the example illustrated inFIG.8, the fourth reflection peaks from the short wavelengths are matched among the reflection peaks of the reflection spectrum of the front DBR region and the reflection peaks of the reflection spectrum of the rear DBR region. Accordingly, in the combined reflection spectrum illustrated inFIG.8(c), there is only one reflection peak at which the reflection peak of the reflection spectrum of the front DBR region and the reflection peak of the reflection spectrum of the rear DBR region are matched. FIG.9is a schematic diagram when, as an example of a wavelength-tunable operation of the SSG-DBR laser, a current is injected into the rear DBR region40bof the front DBR region40aand the rear DBR region40bto modulate a refractive index by the carrier plasma effect and shift the reflection spectrum of the rear DBR region40bto the short wavelength side. In this case, the reflection spectra of the front DBR region40aand the rear DBR region40bare matched at the second reflection peak from the short wavelength sides, and the peak of the combined reflection spectrum can also be shifted considerably to the short wavelength side. Even in this case, the reflection peaks of the front DBR region40aand the rear DBR region40bare matched at only one location, and thus the operation can be performed in the single mode. In this way, by adjusting current amounts injected into the front DBR region40aand the rear DBR region40band individually adjusting the reflection spectra, it is possible to use all the plurality of reflection peaks and realize a broad wavelength-tunable width. Here, a relation between a wavelength shift amount occurring by the carrier plasma effect and the reflection peak interval of the SSG will be described. As the above-described wavelength varying operation of the SSG, the oscillation wavelength can be considerably changed by selectively oscillating a plurality of certain reflection peaks by adjusting injection current amounts of the front DBR region40aand the rear DBR region40b. However, in order to oscillate the reflection peaks at wavelengths between the reflection peaks, as in a general DBR laser that includes a uniform diffraction grating, it is necessary to simultaneously inject a current into the front DBR region40aand the rear DBR region40band simultaneously shift the reflection peaks. That is, in order to realize an SSG-DBR capable of oscillating the reflection peaks at all the wavelengths between the reflection peaks, it is necessary to cause the wavelength-tunable width obtained by the carrier plasma effect to be large rather than the fact that one of Δλfrontand Δλrearis larger. In other words, when the SSG-DBR laser is designed, it is necessary to design Δλfrontand Δλrearwhich are both less than the wavelength-tunable width obtained by the carrier plasma effect. Otherwise, a wavelength band that cannot be oscillated may occur between the reflection peak. Here, a structure of the wavelength-tunable DBR laser according to Example 3 will be described. A manufacturing process and the structure of the wavelength-tunable DBR laser are the same as those of the wavelength-tunable DBR laser according to Example 2 except that an SSG is adopted as the diffraction gratings408aand408bof the front DBR region40aand the rear DBR region40b. That is, the rear DBR region40b, the phase adjustment region30, the active region10, the front DBR region, and the SOA region are integrated in this order in the optical axis direction. A layer structure of the DBR core layers406aand406bof the front DBR region40aand the rear DBR region40bhas an n-InP layer, an n-InAlAs layer, an i-InGaAsP (1.1 Q) layer, a p-InAlAs layer, and a p-InP layer in this order from the side of the n-InP substrate402. The p-side InAlAs layer and the n-side InAlAs layer function as barrier layers. As described in Example 2, a wavelength-tunable width is about 6 nm when this DBR structure is used. Accordingly, it is necessary to design the front and rear SSG-DBR regions of a trial production element in this example so that the reflection peak interval is equal to or less than 6 nm in both the regions. Here, the reflection peak interval Δλfrontof the front DBR region40awas designed to 5.2 nm and the reflection peak interval Δλrearof the rear DBR region40bwas designed to 5.0 nm. Wavelength-tunable feature evaluation of the trial production wavelength-tunable DBR laser (the SSG-DBR laser) is performed. Here, currents injected into the active region10and the SOA region50are set to 90 mA and 100 mA. Different current sources is used for the front DBR region40aand the rear DBR region40bto measure oscillation spectra when the currents are changed from 0 to 60 mA individually at intervals of 1 mA. At this time, the phase adjustment region30is adjusted in the range of 0 to 10 mA under each condition so that that the SMSR is the smallest. A result obtained by plotting all the peak wavelengths of the measured oscillation spectra is illustrated inFIG.10. Each curve inFIG.10shows a reflection peak of the SSG-DBR region. In this element, the SSG is designed so that both the front DBR region40aand the rear DBR region40bhave seven reflection peaks. From the measurement result, it is possible to confirm that seven reflection peaks cannot be obtained. It can be confirmed that each curve is shifted to the short-wavelength side with the injection of the current. A wavelength-tunable width which one reflection peak can take indicates a change width of the refractive index by the carrier plasma effect. Because the same element structure as that of Example 2 is adopted to this element except for the diffraction grating, a wavelength-tunable width of about 6 nm which is the same as that of the element of Example 2 can be obtained. Except for the diffraction grating structure, in the wavelength-tunable DBR laser according to this example, the layer structure of each region, the length of each region, and the manufacturing process are all the same as those of the manufacturing device according to Example 2. | 35,700 |
11862936 | DESCRIPTION OF EMBODIMENTS [Optical Member] The optical member according to an embodiment of the present invention is an optical member for use in a laser module that includes a surface emitting laser light source, in which the optical member includes a wire containing an electrically conductive substance. Any material that can be used in the optical field can be adopted, without particular limitation, as the material constituting the optical member according to an embodiment of the present invention. For example, plastic, optical glass such as BK7 or SF2, quartz glass such as synthetic quartz, or inorganic glass such as calcium fluoride crystals can be used. Among these, an optical member formed from plastic that is easily molded and processed is preferred. Furthermore, from the perspective of providing superior heat resistance that does not easily cause cracking or peeling even during heat treatment in the reflow process, the optical member is also preferably an optical member formed from a hybrid material that is a laminate of plastic and inorganic glass (hereinafter, also referred to as “hybrid optical member”). The hybrid optical member is not particularly limited as long as it has a laminate structure of plastic and inorganic glass, and examples thereof include a laminate of a plastic layer on one or both sides of a substrate formed from inorganic glass on which an optical element is formed; and a laminate in which a plastic layer on which an optical element is formed is laminated on one or both side of a substrate made of flat inorganic glass on which no optical element is formed. The hybrid optical member is preferably a laminate in which a plastic layer on which an optical element is formed on one side of a substrate made of flat inorganic glass because the optical element is easily formed. As the plastic that constitutes the optical member according to an embodiment of the present invention, a plastic that can be used in the optical field can be adopted without particular limitation. For example, a thermoplastic resin composition and a curable resin composition can be used. However, a curable resin composition having excellent mass productivity and moldability is preferred. As the thermoplastic resin composition constituting the optical member according to an embodiment of the present invention, a thermoplastic resin composition that can be used in the optical field can be adopted without particular limitation, and examples thereof include (meth)acrylic resins, alicyclic structure-containing resins, styrene-based resins, polyamide resins, polycarbonate resins, polyester resins, polyether resins, urethane resins, and thiourethane resins. These thermoplastic resins can be molded into the optical member according to an embodiment of the present invention by known molding methods such as press molding, extrusion molding, and injection molding, but injection molding is preferable from the perspective of moldability and productivity. As the curable resin composition constituting the optical member according to an embodiment of the present invention, a curable resin composition that can be used in the optical field can be adopted without particular limitation, and examples thereof include epoxy-based cationic curable resin compositions, acrylic radical curable resin compositions, and curable silicone resin compositions. Of these, an epoxy-based cationic curable resin composition (curable epoxy resin composition) that cures in a short time, has a short casting time to a mold, a small curing shrinkage rate and excellent dimensional stability, and does not undergo oxygen inhibition during curing is preferred. As the epoxy resin, a well-known or commonly used compound having one or more epoxy groups (oxirane ring) in a molecule can be used, and examples thereof include alicyclic epoxy compounds, aromatic epoxy compounds, and aliphatic epoxy compounds. In an embodiment of the present invention, among them, in terms of being able to form a cured product with excellent heat resistance and transparency, especially, being able to form an excellent cured product that does not easily cause cracking or peeling even during heat treatment in the reflow process, a polyfunctional alicyclic epoxy compound having an alicyclic structure and two or more epoxy groups as functional groups in one molecule is preferred. Examples of the polyfunctional alicyclic epoxy compounds specifically include: (i) a compound having an epoxy group constituted of two adjacent carbon atoms and an oxygen atom that constitute an alicyclic ring (i.e., an alicyclic epoxy group); (ii) a compound having an epoxy group directly bonded to an alicyclic ring with a single bond; and (iii) a compound having an alicyclic ring and a glycidyl group. An example of the above compound (i) having an alicyclic epoxy group includes a compound represented by Formula (i) below. In Formula (i) above, X represents a single bond or a linking group (a divalent group having one or more atoms). Examples of the linking group include a divalent hydrocarbon group, an epoxidized alkenylene group in which carbon-carbon double bonds are partially or entirely epoxidized, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide group, and a linked group in which a plurality of the above is linked. Note that a substituent (for example, such as an alkyl group) may be bonded to a cyclohexene oxide group in Formula (i). Examples of the divalent hydrocarbon group include a linear or branched alkylene group having from 1 to 18 carbon atoms and a divalent alicyclic hydrocarbon group. Examples of the linear or branched alkylene group having from 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, and a trimethylene group. Examples of the divalent alicyclic hydrocarbon group include a cycloalkylene group (including a cycloalkylidene group), such as a 1,2-cyclopentylene group, a 1,3-cyclopentylene group, a cyclopentylidene group, a 1,2-cyclohexylene group, a 1,3-cyclohexylene group, a 1,4-cyclohexylene group, and a cyclohexylidene group. Examples of the alkenylene group in the epoxidized alkenylene group in which one, some, or all carbon-carbon double bond(s) is (are) epoxidized (which may be referred to as the “epoxidized alkenylene group”) include a linear or branched alkenylene group having from 2 to 8 carbon atoms, such as a vinylene group, a propenylene group, a 1-butenylene group, a 2-butenylene group, a butadienylene group, a pentenylene group, a hexenylene group, a heptenylene group, and an octenylene group. In particular, the epoxidized alkenylene group is preferably an epoxidized alkenylene group in which all of the carbon-carbon double bond(s) is/are epoxidized and more preferably an epoxidized alkenylene group having from 2 to 4 carbon atoms in which all of the carbon-carbon double bond(s) is/are epoxidized. The linking group in the above X is, in particular, preferably a linking group containing an oxygen atom, and specifically, examples thereof include —CO—, —O—CO—O—, —COO—, —O—, —CONH—, and an epoxidized alkenylene group; a group in which a plurality of these groups are linked; and a group in which one or two or more of these groups and one or more of the divalent hydrocarbon groups are linked. Representative examples of the compound represented by Formula (i) above include (3,4,3′,4′-diepoxy)bicyclohexyl, bis(3,4-epoxycyclohexylmethyl)ether, 1,2-epoxy-1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, 2,2-bis(3,4-epoxycyclohexane-1-yl)propane, 1,2-bis(3,4-epoxycyclohexane-1-yl)ethane, and compounds represented by Formulas (i-1) to (i-10) below. L in Formula (i-5) below is an alkylene group having from 1 to 8 carbons, and, among them, preferably a linear or branched alkylene group having from 1 to 3 carbons, such as a methylene group, an ethylene group, a propylene group, or an isopropylene group. In Formulas (i-5), (i-7), (i-9), and (i-10) below, n1to n8each represent an integer of 1 to 30. The above compound (i) having an alicyclic epoxy group also includes an epoxy-modified siloxane. Examples of the epoxy-modified siloxane include a chain or cyclic polyorganosiloxane having a constituent unit represented by Formula (i′) below. In Formula (i′) above, R1represents a substituent containing an epoxy group represented by Formula (Ia) or (Ib) below, and R2represents an alkyl group or an alkoxy group. In the formulas, R1aand R1bare the same or different and represent a linear or branched alkylene group, and examples thereof include a linear or branched alkylene group having from 1 to 10 carbons, such as a methylene group, a methyl methylene group, a dimethyl methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a decamethylene group. The epoxy equivalent (in accordance with JIS K7236) of the epoxy-modified siloxane is, for example, from 100 to 400 and preferably from 150 to 300. As the epoxy-modified siloxane, for example, commercially available products can be used, for example, such as an epoxy-modified cyclic polyorganosiloxane represented by Formula (i′-1) below (trade name “X-40-2670”, available from Shin-Etsu Chemical Co., Ltd.). Examples of the above compound (ii) having an epoxy group directly bonded to an alicyclic ring with a single bond include a compound represented by Formula (ii) below. In Formula (ii), R′ is a group resulting from elimination of p hydroxyl groups (—OH) from a structural formula of a p-hydric alcohol (p-valent organic group), and p and n9each represent a natural number. Examples of the p-hydric alcohol [R′—(OH)p] include polyhydric alcohols (alcohols having from 1 to 15 carbon atoms), such as 2,2-bis(hydroxymethyl)-1-butanol. Here, p is preferably from 1 to 6, and n9is preferably from 1 to 30. When p is 2 or greater, n9in each group in square brackets (the outer brackets) may be the same or different. Examples of the compound represented by Formula (ii) above specifically include 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol [for example, such as the trade name “EHPE3150” (available from Daicel Corporation)]. Examples of the above compound (iii) having an alicyclic ring and a glycidyl group include hydrogenated aromatic glycidyl ether-based epoxy compounds, such as a hydrogenated bisphenol A epoxy compound, a hydrogenated bisphenol F epoxy compound, a hydrogenated bisphenol enoxy compound, a hydrogenated phenol novolac epoxy compound, a hydrogenated cresol novolac epoxy compound, a hydrogenated cresol novolac epoxy compound of bisphenol A, a hydrogenated naphthalene epoxy compound, and a hydrogenated product of a trisphenol methane epoxy compound. The polyfunctional alicyclic epoxy compound is preferably the compound (i) having an alicyclic epoxy group and particularly preferably a compound represented by Formula (i) above (in particular, (3,4,3′,4′-diepoxy)bicyclohexyl), in terms of providing a cured product having high surface hardness and excellent transparency. The curable resin composition in an embodiment of the present invention may contain an additional curable compound in addition to the epoxy resin as the curable compound and can contain, for example, one type, or two or more types of cationic curable compounds, such as an oxetane compound and a vinyl ether compound. A proportion of the epoxy resin in a total amount (100 wt. %) of the curable compound contained in the curable resin composition is, for example, 50 wt. % or greater, preferably 60 wt. % or greater, particularly preferably 70 wt. % or greater, most preferably 80 wt. % or greater, and the upper limit is, for example, 100 wt. % and preferably 90 wt. %. In addition, a proportion of the compound (i) having an alicyclic epoxy group in the total amount (100 wt. %) of the curable compound contained in the curable resin composition is, for example, 20 wt. % or greater, preferably 30 wt. % or greater, particularly preferably 40 wt. % or greater, and the upper limit is, for example, 70 wt. % and preferably 60 wt. %. A proportion of the compound represented by Formula (i) in the total amount (100 wt. %) of the curable compound contained in the curable resin composition is, for example, 10 wt. % or greater, preferably 15 wt. % or greater, particularly preferably 20 wt. % or greater, and the upper limit is, for example, 50 wt. % and preferably 40 wt. %. The curable resin composition preferably contains a polymerization initiator along with the curable compound, and particularly preferably contains one or more photopolymerization or thermal polymerization initiators (photocationic or thermal cationic polymerization initiators). The photocationic polymerization initiator is a compound that initiates curing reaction of the curable compound (in particular, the cationic curable compound) contained in the curable resin composition by generating an acid with light irradiation and is formed of a cationic moiety that absorbs light and an anionic moiety that serves as a source for generating the acid. Examples of the photocationic polymerization initiator include diazonium salt-based compounds, iodonium salt-based compounds, sulfonium salt-based compounds, phosphonium salt-based compounds, selenium salt-based compounds, oxonium salt-based compounds, ammonium salt-based compounds, and bromine salt-based compounds. In the present invention, among these, use of a sulfonium salt-based compound is preferred because a cured product having excellent curability can be formed. Examples of the cationic moiety of the sulfonium salt-based compound include arylsulfonium ions (in particular, triarylsulfonium ions), such as a (4-hydroxyphenyl)methylbenzylsulfonium ion, a triphenyl sulfonium ion, a diphenyl[4-(phenylthio)phenyl]sulfonium ion, a 4-(4-biphenylthio)phenyl-4-biphenylylphenylsulfonium ion, and a tri-p-tolylsulfonium ion. Examples of the anion moiety of the photocationic polymerization initiator include [(Y)sB(Phf)4-s]−(in the formula, Y represents a phenyl group or a biphenylyl group, Phf represents a substituted phenyl group in which at least one of hydrogen atoms is replaced with at least one selected from a perfluoroalkyl group, a perfluoroalkoxy group, or a halogen atom, and s is an integer of 0 to 3), BF4−, [(Rf)tPF6-t]−(in the formula, Rf represents an alkyl group in which 80% or more of hydrogen atoms are replaced with fluorine atoms, and t represents an integer of 0 to 5; AsF6−; SbF6−; and SbF5OH−. Examples of the photocationic polymerization initiator that can be used include (4-hydroxyphenyl)methylbenzylsulfonium tetrakis(pentafluorophenyl)borate; 4-(4-biphenylylthio)phenyl-4-biphenylylphenylsulfonium tetrakis(pentafluorophenyl)borate; 4-(phenylthio)phenyldiphenylsulfonium phenyltris(pentafluorophenyl)borate; [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium phenyltris(pentafluorophenyl)borate; diphenyl[4-(phenylthio)phenyl]sulfonium tris(pentafluoroethyl)trifluorophosphate; diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate; diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate; 4-(4-biphenylylthio)phenyl-4-biphenylylphenylsulfonium tris(pentafluoroethyl)trifluorophosphate; bis[4-(diphenylsulfonio)phenyl]sulfide phenyltris(pentafluorophenyl)borate; [4-(2-thioxanthonylthio)phenyl]phenyl-2-thioxanthonylsulfonium phenyltris(pentafluorophenyl)borate; 4-(phenylthio)phenyldiphenylsulfonium hexafluoroantimonate; and commercially available products under trade names, such as “Cyracure UVI-6970”, “Cyracure UVI-6974”, “Cyracure UVI-6990”, and “Cyracure UVI-950” (these are available from Union Carbide Corporation, USA), “Irgacure 250”, “Irgacure 261”, “Irgacure 264”, and “CG-24-61” (these are available from BASF), “Optomer SP-150”, “Optomer SP-151”, “Optomer SP-170”, and “Optomer SP-171” (these are available from Adeka Corporation), “DAICAT II” (available from Daicel Corporation), “UVAC 1590” and “UVAC 1591” (these are available from Daicel-Cytec Co., Ltd.), “CI-2064”, “CI-2639”, “CI-2624”, “CI-2481”, “CI-2734”, “CI-2855”, “CI-2823”, “CI-2758”, and “CIT-1682” (these are available from Nippon Soda Co., Ltd.), “PI-2074” (tetrakis(pentafluorophenyl)borate tricumyliodonium salt, available from Rhodia), “FFC 509” (available from 3M), “BBI-102”, “BBI-101”, “BBI-103”, “MPI-103”, “TPS-103”, “MDS-103”, “DTS-103”, “NAT-103”, and “NDS-103” (these are available from Midori Kagaku Co., Ltd.), “CD-1010”, “CD-1011”, and “CD-1012” (these are available from Sartomer, USA), and “CPI-100P” and “CPI-101A” (these are available from San-Apro Ltd.). The thermal cationic polymerization initiator is a compound that initiates a curing reaction of the cationic curable compound contained in the curable resin composition by generating an acid with heating treatment and is formed of a cationic moiety that absorbs heat and an anionic moiety that serves as a source for generating the acid. A single thermal cationic polymerization initiator can be used alone, or two or more thermal cationic polymerization initiators can be used in combination. Examples of the thermal cationic polymerization initiator include iodonium salt compounds, and sulfonium salt compounds. Examples of the cationic moiety of the thermal cationic polymerization initiator include 4-hydroxyphenyl-methyl-benzylsulfonium ions, 4-hydroxyphenyl-methyl-(2-methylbenzyl)sulfonium ions, 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium ions, and p-methoxycarbonyloxyphenyl-benzyl-methylsulfonium ions. Examples of the anionic moiety of the thermal cationic polymerization initiator include the same examples as those of the anionic moiety of the photocationic polymerization initiator indicated above. Examples of the thermal cationic polymerization initiator include 4-hydroxyphenyl-methyl-benzylsulfonium phenyl tris(pentafluorophenyl) borate, 4-hydroxyphenyl-methyl-(2-methylbenzyl) sulfonium phenyl tris(pentafluorophenyl) borate, 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium phenyl tris(pentafluorophenyl) borate, and p-methoxycarbonyloxyphenyl-benzyl-methylsulfonium phenyl tris(pentafluorophenyl) borate. The content of the polymerization initiator is, for example, in a range of 0.1 to 5.0 parts by weight relative to 100 parts by weight of the curable compound (in particular, the cationic curable compound) contained in the curable resin composition. When the content of the photopolymerization initiator is less than the above range, curing failures may occur. On the other hand, when the content of the photopolymerization initiator exceeds the above range, coloration of the cured product tends to occur. The curable resin composition in the present invention can be produced by mixing the curable compound, the polymerization initiator, and, as necessary, an additional component (for example, such as a solvent, an antioxidant, a surface conditioner, a photosensitizer, an anti-foaming agent, a leveling agent, a joining agent, a surfactant, a flame retardant, an ultraviolet absorber, and a colorant). The additional component is blended in an amount of, for example, 20 wt. % or less, preferably 10 wt. % or less, particularly preferably 5 wt. % or less of the total amount of the curable resin composition. The viscosity of the curable resin composition of the present invention at 25° C. is not particularly limited, but is preferably 5000 mPa·s or less, more preferably 2500 mPa·s or less. Adjusting the viscosity of the curable resin composition according to an embodiment of the present invention to the above-described range may improve fluidity, and suppress air bubble residues. Thus, it is possible to fill the curable resin composition into a mold while suppressing the increase in injection pressure. That is, coatability and fillability can be improved, and workability can be improved throughout the molding operation of the curable resin composition according to an embodiment of the present invention. The viscosity in the present specification is a value measured using a rheometer (“PHYSICA UDS200” available from Paar Physica) under the conditions of a temperature of 25° C. and a rotational speed of 20/sec. Commercially available products such as the trade names “CELVENUS OUH106” and “CELVENUS OTM107” (there are available from Daicel Corporation) can also be used as the curable resin composition in the present invention. The optical member according to an embodiment of the present invention can obtain an optical member formed from a cured product of the curable resin composition by molding the curable resin composition using a mold and then curing. Examples of the method for molding the curable resin composition using a mold include methods (1) and (2) below. (1) A method of applying the curable resin composition to a mold, pressing a substrate from above, curing the curable resin composition, and then detaching the mold; and (2) A method of applying the curable resin composition to at least one of an upper mold or a lower mold, combining the upper mold and the lower mold, curing the curable resin composition, and then detaching the upper mold and the lower mold. For example, when a photocurable resin composition is used as the curable resin composition, a substrate having a light transmittance of 90% or greater at a wavelength of 400 nm is preferably used as the substrate described above, and a substrate made of inorganic glass such as quartz glass or optical glass can be suitably used. In the method (1) above, when a substrate made of inorganic glass is used, a hybrid optical member that is a laminate of a cured product of a curable resin composition and inorganic glass can be obtained. Further, the light transmittance at the wavelength can be determined using a substrate (thickness: 1 mm) as a test piece and using a spectrophotometer to measure the light transmittance at the wavelength irradiated to the test piece. The method of applying the curable resin composition is not particularly limited, and examples thereof include methods using a dispenser, a syringe, or the like. Furthermore, the curable resin composition is preferably applied to a center portion of the mold. For example, when a photocurable resin composition is used as the curable resin composition, the curable resin composition can be cured by ultraviolet irradiation. Examples of the light source used during the ultraviolet light irradiation include a high-pressure mercury-vapor lamp, an ultrahigh-pressure mercury-vapor lamp, a carbon-arc lamp, a xenon lamp, and a metal halide lamp. The irradiation time is dependent of the type of the light source, the distance between the light source and the coated surface, and other conditions, but is several tens of seconds at the longest. The illuminance is approximately from 5 to 200 mW. After the ultraviolet light irradiation, the curable composition may be heated (post-curing) as necessary to facilitate curing. For example, when a thermosetting resin composition is used as the curable resin composition, the curable resin composition can be cured by heating treatment. The heating temperature is, for example, approximately from 60 to 150° C. The heating time is, for example, approximately from 0.2 to 20 hours. The shape of the optical member according to an embodiment of the present invention is not particularly limited as long as it can be used in the optical field, and can be selected, for example, from a plate shape, a sheet shape, a film shape, a lens shape, a prism shape, a columnar shape, a conical shape, and the like depending on the purpose and application. A substrate shape such as a plate shape, a sheet shape, a film shape, or the like is preferred from the perspective of easily controlling the laser light, when the optical member includes an optical element described below. When the optical member according to an embodiment of the present invention has a substrate shape, the thickness thereof can also be appropriately set depending on the application and purpose, and can be appropriately selected from a range of from 100 to 2000 μm, and preferably from 100 to 1000 μm. The optical member according to an embodiment of the present invention preferably has high transparency. The total light transmittance of the optical member according to an embodiment of the present invention is not particularly limited but is preferably 70% or greater and more preferably 80% or greater. In addition, the upper limit of the total light transmittance is not particularly limited but is, for example, 99%. The total light transmittance of the optical member according to an embodiment of the present invention can be easily controlled to the above range, for example, by using the cured product of the curable resin composition described above as the material. Here, the total light transmittance can be measured according to JIS K7361-1. The haze of the optical member according to an embodiment of the present invention is not particularly limited but is preferably 10% or less and more preferably 5% or less. In addition, the lower limit of the haze is not particularly limited but is, for example, 0.10%. The haze of the optical member according to an embodiment of the present invention can be easily controlled to the above range, for example, by using the cured product of the curable resin composition described above as the material. Here, the haze can be measured according to JIS K7136. The optical member according to an embodiment of the present invention preferably includes an optical element. As the optical element included in the optical member according to an embodiment of the present invention, an optical element that can be used in the optical field can be adopted without particular limitation, and examples thereof include diffractive optical elements, microlens arrays, prisms, and polarizing plates. A diffractive optical element and a microlens array, which are suitable for controlling the laser light, are preferred. The diffractive optical element (DOE) is an optical element that uses a diffraction phenomenon of light such as grating hologram to change the traveling direction of the light, which diffracts light by a periodic structure (diffraction groove) formed in the optical member and forms the light into any structural light. The structural light of the laser light that is controlled by the diffractive optical element included in the optical member according to an embodiment of the present invention is not particularly limited, but examples thereof include a dot pattern, and uniform surface irradiated light. The structural light can be appropriately selected depending on the application and purpose. The microlens array has a structure in which a plurality of microlenses having a size of approximately tens of μm are arranged, and functions as a “diffuser” that diffuses and uniformizes the laser light emitted from the surface emitting laser light source. The respective microlenses constituting the microlens array may have the same shape, or the microlens array may have a random structure in which microlenses different in shape are arranged. Whether the microlenses have the same shape or different shapes may be appropriately selected depending on the application and purpose. The optical element included in the optical member according to an embodiment of the present invention can be formed by a known method. For example, a mold having a molding surface having an inverted shape to the shape of a desired optical element is used as the mold for molding the curable resin composition described above, and thus the optical element can be formed in a region corresponding to the inverted shape of the optical member. Furthermore, a method of forming a desired optical pattern on the optical member by electron beam lithography or the like may also be adopted. In addition, a member including an optical element may be separately laminated onto an optical member that does not include an optical element. A material similar to the material constituting the optical member according to an embodiment of the present invention can be used as the material constituting the member including an optical element. The material that constitutes the member including an optical element may be the same material as or a different material from the material constituting the optical member according to an embodiment of the present invention. The member including an optical element can be available from a method similar to the method for manufacturing the optical member including the optical element according to an embodiment of the present invention. The optical element included in the optical member according to an embodiment of the present invention may be formed entirely on the surface of the optical member or may be formed partially thereon. Specifically, in a case where the optical member has a substrate shape, an optical element may be formed entirely on at least one side of the optical member, or an optical element may be formed partially thereon. Additionally, an optical element may be formed on only one side of the substrate-shaped optical member, or an optical element may be formed on both sides thereof. An aspect is preferred in which a substrate-shaped optical member including an optical element preferably includes a region in which an optical element is formed (hereinafter, also referred to as “optical element region”) and a region in which no optical element is formed (hereinafter, also referred to as “non-optical element region”). Especially, an aspect is preferred in which the optical element region is formed in a center portion of the substrate of the optical member, and the non-optical element region is provided on the periphery of the optical element region (outer periphery of the substrate of the optical member). Note that, even in a case where an optical element is formed on only one side of the substrate-shaped optical member, regions corresponding to the optical element region and the non-optical element region are also interpreted as the optical element region and the non-optical element region, respectively, on the other side on which no optical element is formed. [Wire Containing Electrically Conductive Substance] The optical member according to an embodiment of the present invention includes a wire containing an electrically conductive substance. The electrically conductive substance is not particularly limited as long as it has electrical conductivity, and for example, a metal, a metal oxide, an electrically conductive polymer, an electrically conductive carbon-based substance, or the like can be used. Examples of the metal include gold, silver, copper, chromium, nickel, palladium, aluminum, iron, platinum, molybdenum, tungsten, zinc, lead, cobalt, titanium, zirconium, indium, rhodium, ruthenium, and alloys thereof. Examples of the metal oxide include chromium oxide, nickel oxide, copper oxide, titanium oxide, zirconium oxide, indium oxide, aluminum oxide, zinc oxide, tin oxide, or composite oxides thereof such as composite oxides of indium oxide and tin oxide (ITO) and complex oxides of tin oxide and phosphorus oxide (PTO). Examples of the electrically conductive polymer include polyacetylene, polyaniline, polypyrrole, and polythiophene. Examples of the electrically conductive carbon-based substance include carbon black, SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT, pyrolytic carbon, natural graphite, and artificial graphite. These electrically conductive substances can be used alone, or two or more types thereof can be used in combination. The electrically conductive substance is preferably a metal or metal oxide having excellent electrical conductivity and easy to form a wire, and more preferably a metal. Gold, silver, copper, indium, or the like is preferred, and silver is particularly preferred because it is mutually fused at a temperature of approximately 100° C. and can form a wire with excellent electrical conductivity even on a plastic optical member. In addition to the electrically conductive substance, the wire containing the electrically conductive substance may contain an additive such as a doping agent, a reducing agent, an antioxidant, a coupling agent (such as a silane coupling agent), or the like, from the perspective of improving electrical conductivity, steady contact with the optical member, and the like. As a method for forming the wire containing the electrically conductive substance on the optical member, known methods such as a printing process, a sputtering method, a vacuum deposition method, a chemical vapor deposition (CVD) method, a metal organic chemical vapor deposition (MOCVD) method, and a laser ablation method (Pulsed Laser Ablation Deposition (PLAD)) can be used without limitation. From the perspective of easily forming a wire of a desired width at a target position of the optical member, a printing process and a sputtering method are preferred, and a printing process is particularly preferred. As the printing process, a known printing process can be used without particular limitation, and examples thereof include inkjet printing, gravure printing, flexographic printing, screen printing, and offset printing. From the perspective of easily forming a wire of a desired width at a target position of the optical member, inkjet printing, gravure printing, flexographic printing, or screen printing is preferred, and inkjet printing or screen printing is particularly preferred. The inkjet printing according to an embodiment of the present invention is a method that includes applying an ink containing an electrically conductive substance from a nozzle to an optical member to form a wire. The ink containing the electrically conductive substance used in the inkjet printing in the present invention is not particularly limited as long as it can be used for inkjet printing, but from the perspective of easily forming a wire of a desired width at a target position of the optical member, an ink containing “surface-modified metal nanoparticles having a configuration in which surfaces of the metal nanoparticles are coated with an organic protective agent” (hereinafter, also referred to simply as “surface-modified metal nanoparticles”) is preferred. The surface-modified metal nanoparticles have a configuration in which surfaces of the metal nanoparticles are coated with an organic protective agent. As such, the surface-modified metal nanoparticles have excellent dispersibility because the spacing between the metal nanoparticles is ensured and thus agglomeration is suppressed. The surface-modified metal nanoparticles include a metal nanoparticle portion and a surface modification portion that coats the metal nanoparticle portion (i.e., the portion that coats the metal nanoparticles and is formed of an organic protective agent), and the proportion of the surface modification portion is, for example, approximately from 1 to 20 wt. % (preferably from 1 to 10 wt. %) of the weight of the metal nanoparticle portion. Each weight of the metal nanoparticle portion and the surface modification portion in the surface-modified metal nanoparticles can be determined, for example, from the weight loss rate in a certain temperature range by subjecting the surface-modified metal nanoparticles to thermogravimetry. The average primary particle diameter of the metal nanoparticle portion in the surface-modified metal nanoparticles is, for example, from 0.5 to 100 nm, preferably from 0.5 to 80 nm, more preferably from 1 to 70 nm, and even more preferably from 1 to 60 nm. The metal constituting the metal nanoparticle portion of the surface-modified metal nanoparticles can be a metal having the above-described electrical conductivity, and examples thereof include gold, silver, copper, nickel, aluminum, rhodium, cobalt, and ruthenium. Silver nanoparticles are preferred as the metal nanoparticles according to an embodiment of the present invention in that the silver nanoparticles are fused to each other at a temperature of approximately 100° C., and can form a wire having excellent electrical conductivity on the optical member. Therefore, the surface-modified metal nanoparticles are preferably surface-modified silver nanoparticles, and a silver ink is preferred as the ink for inkjet printing. The organic protective agent that constitutes the surface modification portion of the surface-modified metal nanoparticles is preferably a compound having at least one type of functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, a sulfo group, and a thiol group, particularly preferably a compound having from 4 to 18 carbon atoms and having at least one type of functional group selected from the group consisting of an amino group, a sulfo group, and a thiol group, most preferably a compound having an amino group, and especially preferably a compound having from 4 to 18 carbon atoms and having an amino group (i.e., an amine having from 4 to 18 carbon atoms). The surface-modified metal nanoparticles can be manufactured, for example, through: mixing a metal compound and an organic protective agent to form a complex containing the metal compound and the organic protective agent (formation of the complex); thermally decomposing the complex (thermal decomposition); and, as necessary, washing the reaction product (washing). Formation of Complex The formation of the complex is to mix a metal compound and an organic protective agent to form a complex containing the metal compound and the organic protective agent. It is preferable to use a silver compound as the metal compound, and because the nano-sized silver particles are fused to each other at a temperature of approximately 100° C., and thus a wire having excellent electrical conductivity can be formed on the optical member. Particularly, a silver compound that is readily decomposed upon heating and produces metallic silver is preferably used. Examples of such a silver compound include silver carboxylates, such as silver formate, silver acetate, silver oxalate, silver malonate, silver benzoate, and silver phthalate; silver halides, such as silver fluoride, silver chloride, silver bromide, and silver iodide; and silver sulfate, silver nitrate, and silver carbonate. Among them, silver oxalate is preferred in that it has a high silver content, can be thermally decomposed without using a reducing agent, and thus an impurity derived from the reducing agent is less likely to be mixed into the ink. As the organic protective agent, a compound having at least one type of functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, a sulfo group, and a thiol group, in that the coordination of non-covalent electron pairs in the heteroatom to the metal nanoparticles can exert an effect of strongly suppressing agglomeration between the metal nanoparticles. A compound having from 4 to 18 carbon atoms and having at least one type of functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, a sulfo group, and a thiol group is particularly preferred. The organic protective agent is preferably a compound having an amino group, and most preferably a compound having from 4 to 18 carbon atoms and having an amino group, that is, an amine having from 4 to 18 carbon atoms. The amine is a compound in which at least one hydrogen atom of ammonia is substituted with a hydrocarbon group, and includes a primary amine, a secondary amine, and a tertiary amine. In addition, the amine may be a monoamine or a polyamine, such as a diamine. One of these solvents can be used alone or two or more in combination. The amine preferably contains at least one selected from a monoamine (1) having 6 or more carbon atoms in total and represented by Formula (a-1) below, where R1, R2, and R3are identical or different and are hydrogen atoms or monovalent hydrocarbon groups (with the provisio that the case in which R1, R2, and R3are all hydrogen atoms is omitted); monoamine (2) having 5 or less carbon atoms in total and represented by Formula (a-1) below, where R1, R2, and R3are identical or different and are hydrogen atoms or monovalent hydrocarbon groups (with the provisio that the case in which R1, R2, and R3are all hydrogen atoms is omitted); and a diamine (3) having 8 or less carbon atoms in total and represented by Formula (a-2), where R4to R7are identical or different and are hydrogen atoms or monovalent hydrocarbon groups, and R8is a divalent hydrocarbon group; and in particular, preferably contains the monoamine (1) in combination with the monoamine (2) and/or the diamine (3). The hydrocarbon group includes an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and among them, an aliphatic hydrocarbon group or an alicyclic hydrocarbon group is preferred, and in particular, an aliphatic hydrocarbon group is preferred. Thus, the monoamine (1), the monoamine (2), and the diamine (3) are preferably an aliphatic monoamine (1), an aliphatic monoamine (2), and an aliphatic diamine (3). In addition, the monovalent aliphatic hydrocarbon group includes an alkyl group and an alkenyl group. The monovalent alicyclic hydrocarbon group includes a cycloalkyl group and a cycloalkenyl group. Furthermore, the divalent aliphatic hydrocarbon group includes an alkylene group and an alkenylene group, and the divalent alicyclic hydrocarbon group includes a cycloalkylene group and a cycloalkenylene group. Examples of the monovalent hydrocarbon group in R1, R2, and R3may include alkyl groups having approximately from 1 to 18 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a decyl group, a dodecyl group, a tetradecyl group, an octadecyl group; alkenyl groups having approximately from 2 to 18 carbon atoms, such as a vinyl group, an allyl group, a methallyl group, a 1-propenyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a 4-pentenyl group, and a 5-hexenyl group; cycloalkyl groups having approximately from 3 to 18 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group; and cycloalkenyl groups having approximately from 3 to 18 carbon atoms, such as a cyclopentenyl group and a cyclohexenyl group. Examples of the monovalent hydrocarbon groups in R4to R7may include, among those exemplified above, alkyl groups having approximately from 1 to 7 carbon atoms, alkenyl groups having approximately from 2 to 7 carbon atoms, cycloalkyl groups having approximately from 3 to 7 carbon atoms, and cycloalkenyl groups having approximately from 3 to 7 carbon atoms. Examples of the divalent hydrocarbon group in R8may include alkylene groups having from 1 to 8 carbon atoms, such as a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a heptamethylene group; and alkenylene groups having from 2 to 8 carbon atoms, such as a vinylene group, a propenylene group, a 1-butenylene group, a 2-butenylene group, a butadienylene group, a pentenylene group, a hexenylene group, a heptenylene group, and an octenylene group. The hydrocarbon groups in the above R1to R8may have a substituent of various types [e.g., such as a halogen atom, an oxo group, a hydroxyl group, a substituted oxy group (e.g., such as a C1-4alkoxy group, a C6-10aryloxy group, a C7-16aralkyloxy group, or a C1-4acyloxy group), a carboxyl group, a substituted oxycarbonyl group (e.g., such as a C1-4alkoxycarbonyl group, a C6-10aryloxycarbonyl group, or a C7-16aralkyloxycarbonyl group), a cyano group, a nitro group, a sulfo group, or a heterocyclic group]. In addition, the hydroxyl group and the carboxyl group may be protected with a protecting group commonly used in the field of organic synthesis. The monoamine (1) is a compound that is adsorbed on the surfaces of the metal nanoparticles and prevents agglomeration of the metal nanoparticles and enlargement of the agglomeration, that is, a compound having a function of imparting high dispersibility to the metal nanoparticles. Examples of the monoamine (1) include primary monoamines having a linear alkyl group, such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, and n-dodecylamine; primary amines having a branched alkyl group, such as isohexylamine, 2-ethylhexylamine, and tert-octylamine; a primary amine having a cycloalkyl group, such as cyclohexylamine; a primary amine having an alkenyl group, such as oleylamine; secondary amines having a linear alkyl group, such as N,N-dipropylamine, N,N-dibutylamine, N,N-dipentylamine, N,N-dihexylamine, N,N-dipeptylamine, N,N-dioctylamine, N,N-dinonylamine, N,N-didecylamine, N,N-diundecylamine, N,N-didodecylamine, and N-propyl-N-butylamine; secondary amines having a branched alkyl group, such as N,N-diisohexylamine and N,N-di(2-ethylhexyl)amine; tertiary amines having a linear alkyl group, such as tributylamine and trihexylamine; and tertiary amines having a branched alkyl group, such as triisohexylamine and tri(2-ethylhexyl)amine. Among the above monoamines (1), an amine (in particular, a primary amine) having a linear alkyl group having from 6 to 18 carbon atoms in total (more preferably up to 16 and particularly preferably up to 12 carbon atoms in total) is preferred in that such an amine can provide space between the metal nanoparticles when the amino groups is adsorbed on the metal nanoparticle surfaces, thus providing the effect of preventing agglomeration of the metal nanoparticles, and such an amine can be easily removed during sintering. In particular, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodedeyclamine, and the like are preferred. The monoamine (2) has a shorter hydrocarbon chain than that of the monoamine (1), and thus the function of the monoamine (2) itself to impart high dispersibility to the metal nanoparticles is low. However, the monoamine (2) has a high coordination ability to a metal atom due to its higher polarity than that of the monoamine (1), and thus has an effect of promoting complex formation. In addition, the monoamine (2) has a short hydrocarbon chain and thus can be removed from the metal nanoparticle surfaces in a short time (e.g., not longer than 30 minutes and preferably not longer than 20 minutes) even in low-temperature sintering, thus providing a sintered body with excellent electrical conductivity. Examples of the monoamine (2) include a primary amine having a linear or branched alkyl group and having from 2 to 5 carbon atoms in total (preferably from 4 to 5 carbon atoms in total), such as n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, pentylamine, isopentylamine, and tert-pentylamine; and a secondary amine having a linear or branched alkyl group and having from 2 to 5 carbon atoms in total (preferably from 4 to 5 carbon atoms in total), such as N,N-diethylamine. In an embodiment of the present invention, among these, a primary amine having a linear alkyl group and having from 2 to 5 carbon atoms in total (preferably from 4 to 5 carbon atoms in total) is preferred. The diamine (3) has 8 or less carbon atoms in total and has a high coordination ability to a metal atom due to its higher polarity than that of the monoamine (1), and thus has an effect of promoting complex formation. In addition, the diamine (3) has an effect of promoting thermal decomposition of the complex at lower temperature and in a short time in the thermal decomposition of the complex, and the use of the diamine (3) can perform the production of the surface-modified metal nanoparticles more efficiently. Furthermore, the surface-modified metal nanoparticles having a configuration of being coated with the protective agent containing the diamine (3) exhibit excellent dispersion stability in a highly polar dispersion medium. Moreover, the diamine (3) has a short hydrocarbon chain and thus can be removed from the metal nanoparticle surfaces in a short time (e.g., not longer than 30 minutes and preferably not longer than 20 minutes) even by low-temperature sintering, thus providing a sintered body with excellent electrical conductivity. Examples of the diamine (3) may include diamines in which R4to R7in Formula (a-2) are hydrogen atoms, and R8is a linear or branched alkylene group, such as 2,2-dimethyl-1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, and 1,5-diamino-2-methylpentane; diamines in which R4and R6in Formula (a-2) are identical or different and linear or branched alkyl groups, R5and R7are hydrogen atoms, and R8is a linear or branched alkylene group, such as N,N′-dimethylethylenediamine, N,N′-diethylethylenediamine, N,N′-dimethyl-1,3-propanediamine, N,N′-diethyl-1,3-propanediamine, N,N′-dimethyl-1,4-butanediamine, N,N′-diethyl-1,4-butanediamine, and N,N′-dimethyl-1,6-hexanediamine; and diamines in which R4and R5in Formula (a-2) are identical or different and linear or branched alkyl groups, R6and R7are hydrogen atoms, and R8is a linear or branched alkylene group, such as N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, N,N-dimethyl-1,4-butanediamine, N,N-diethyl-1,4-butanediamine, and N,N-dimethyl-1,6-hexanediamine. Among them, diamines in which R4and R5in Formula (a-2) above are identical or different and linear or branched alkyl groups, R6and R7are hydrogen atoms, and R8is a linear or branched alkylene group [in particular, diamines in which R4and R5in Formula (a-2) are linear alkyl groups, R6and R7are hydrogen atoms, and R8is a linear alkylene group] are preferred. In diamines in which R4and R5in Formula (a-2) are identical or different and are linear or branched alkyl groups, and R6and R7are hydrogen atoms, that is, diamines having a primary amino group and a tertiary amino group, the primary amino group has a high coordination ability to a metal atom, but the tertiary amino group has a poor coordination ability to a metal atom, and thus this prevents a resulting complex from becoming excessively complicated, thereby allowing the complex to be thermally decomposed at lower temperature and in a shorter time in the thermal decomposition of the complex. Among them, diamines having 6 or less (e.g., from 1 to 6, preferably from 4 to 6) carbon atoms in total are preferred, and diamines having 5 or less (e.g., from 1 to 5, preferably from 4 to 5) carbon atoms in total are more preferred in that they can be removed from the metal nanoparticle surfaces in a short time in low-temperature sintering. The proportion of the content of the monoamine (1) in the total amount of the organic protective agent contained in the electrically conductive ink according to an embodiment of the present invention, and the proportion of the total content of the monoamine (2) and the diamine (3) therein are preferably within the ranges described below. Content of monoamine (1): for example, from 5 to 65 mol % (the lower limit is preferably 10 mol %, particularly preferably 20 mol %, and most preferably 30 mol %. In addition, the upper limit is preferably 60 mol %, and particularly preferably 50 mol %) Total content of monoamine (2) and diamine (3): for example, from 35 to 95 mol % (the lower limit is preferably 40 mol %, and particularly preferably 50 mol %. In addition, the upper limit is preferably 90 mol %, particularly preferably 80 mol %, and most preferably 70 mol %) The proportion of the content of the monoamine (2) in the total amount of the organic protective agent contained in the electrically conductive ink according to an embodiment of the present invention, and the proportion of the content of the diamine (3) therein are preferably within the ranges described below. Content of monoamine (2): for example, from 5 to 65 mol % (the lower limit is preferably 10 mol %, particularly preferably 20 mol %, and most preferably 30 mol %. In addition, the upper limit is preferably 60 mol %, and particularly preferably 50 mol %) Content of diamine (3): for example, from 5 to 50 mol % (the lower limit is preferably 10 mol %. In addition, the upper limit is preferably 40 mol %, and particularly preferably 30 mol %) The monoamine (1) contained in the above range provides dispersion stability of the metal nanoparticles. With the content of the monoamine (1) below the above range, the metal nanoparticles would tend to be prone to agglomeration. On the other hand, the content of the monoamine (1) exceeding the above range would cause difficulty in removing the organic protective agent from the metal nanoparticle surfaces in a short time when the sintering temperature is low, tending to reduce the electrical conductivity of the resulting sintered body. The monoamine (2) contained in the above range provides the effect of promoting complex formation. In addition, this allows the organic protective agent to be removed from the metal nanoparticle surfaces in a short time even when the sintering temperature is low, providing a sintered body with excellent electrical conductivity. The diamine (3) contained in the above range easily provides the effect of promoting complex formation and the effect of promoting the thermal decomposition of the complex. In addition, the surface-modified metal nanoparticles having a configuration of being coated with the protective agent containing the diamine (3) exhibit excellent dispersion stability in a highly polar dispersion medium. In an embodiment of the present invention, the use of the monoamine (2) and/or the diamine (3) having a high coordination ability to metal atoms of the metal compound is preferred, in that the use can reduce the amount of the monoamine (1) used depending on the proportion of the monoamine (2) and/or the diamine (3) used and can remove the organic protective agent from the metal nanoparticle surfaces in a short time even when the sintering temperature is low, providing a sintered body with excellent electrical conductivity. The amine used as the organic protective agent in an embodiment of the present invention may contain an additional amine other than the monoamine (1), the monoamine (2), and the diamine (3), but the proportion of the total content of the monoamine (1) and the monoamine (2), and the diamine (3) accounting for the total amines contained in the protective agent is, for example, preferably from 60 wt. % or greater, particularly preferably 80 wt. % or greater, and most preferably 90 wt. % or greater. Note that the upper limit is 100 wt. %. That is, the content of the additional amine is preferably not greater than 40 wt. %, particularly preferably not greater than 20 wt. %, and most preferably not greater than 10 wt. %. The amount of the organic protective agent [in particular, monoamine (1)+monoamine (2)+diamine (3)] used is not particularly limited but is preferably approximately from 1 to 50 mol, particularly preferably from 2 to 50 mol, and most preferably from 6 to 50 mol, relative to 1 mol of metal atoms in the metal compound of the raw material. When the amount of the organic protective agent is below the above range, the metal compound not converted to a complex would be prone to remain in the formation of the complex, tending to be difficult to impart sufficient dispersibility to the metal nanoparticles. To further improve the dispersibility of the metal nanoparticles, one or more types of compounds having a carboxyl group (for example, compounds having from 4 to 18 carbon atoms and having a carboxyl group, preferably aliphatic monocarboxylic acids having from 4 to 18 carbon atoms) may be contained together with the compound having an amino group as the organic protective agent. Examples of the aliphatic monocarboxylic acid may include saturated aliphatic monocarboxylic acids having 4 or more carbon atoms, such as butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, and icosanoic acid; and unsaturated aliphatic monocarboxylic acids having 8 or more carbon atoms, such as oleic acid, elaidic acid, linoleic acid, palmitoleic acid, and eicosenoic acid. Among them, saturated or unsaturated aliphatic monocarboxylic acids having from 8 to 18 carbon atoms (in particular, octanoic acid and oleic acid) are preferred. When the carboxyl groups of the aliphatic monocarboxylic acid are adsorbed on the metal nanoparticle surfaces, the saturated or unsaturated aliphatic hydrocarbon chain having from 8 to 18 carbon atoms causes a steric hindrance and thus can provide space between the metal nanoparticles, thus improving the effect of preventing agglomeration of the metal nanoparticles. The amount of the compound having a carboxyl group used is, for example, approximately from 0.05 to 10 mol, preferably from 0.1 to 5 mol, and particularly preferably from 0.5 to 2 mol, relative to 1 mol of metal atoms in the metal compound. The amount of the compound having a carboxyl group used below the above range would cause difficulty in providing an effect of improving dispersion stability. On the other hand, the compound having a carboxyl group, even when used in an excessive amount, would saturate the effect of improving the dispersion stability while it tends to be difficult to remove the compound by low-temperature sintering. The reaction between the organic protective agent and the metal compound is performed in the presence or absence of the dispersion medium. As the dispersion medium, for example, an alcohol having 3 or more carbon atoms can be used. Examples of the alcohol having 3 or more carbon atoms include n-propanol (boiling point: 97° C.), isopropanol (boiling point: 82° C.), n-butanol (boiling point: 117° C.), isobutanol (boiling point: 107.89° C.), sec-butanol (boiling point: 99.5° C.), tert-butanol (boiling point: 82.45° C.), n-pentanol (boiling point: 136° C.), n-hexanol (boiling point: 156° C.), n-octanol (boiling point: 194° C.), and 2-octanol (boiling point: 174° C.). Among them, alcohols having from 4 to 6 carbon atoms are preferred, and in particular, n-butanol and n-hexanol are preferred in that higher temperature can be set for the thermal decomposition of the complex to be performed later and in terms of the convenience of the post-treatment of the resulting surface-modified metal nanoparticles. In addition, the amount of the dispersion medium used is, for example, not less than 120 parts by weight, preferably not less than 130 parts by weight, and more preferably not less than 150 parts by weight, relative to 100 parts by weight of the metal compound. The upper limit of the amount of the dispersion medium used is, for example, 1000 parts by weight, preferably 800 parts by weight, and particularly preferably 500 parts by weight. The reaction between the organic protective agent and the metal compound is preferably performed at ordinary temperature (from 5 to 40° C.). The reaction is accompanied by heat generation due to the coordination reaction of the organic protective agent to the metal compound and thus may be performed while the reaction mixture is appropriately cooled to the above temperature range. The reaction time between the organic protective agent and the metal compound is, for example, approximately from 30 minutes to 3 hours. This results in a metal-organic protective agent complex (metal-amine complex when an amine is used as the organic protective agent). Thermal Decomposition The thermal decomposition is a step of thermally decomposing the resulting metal-organic protective agent complex through the formation of the complex to form the surface-modified metal nanoparticles. It is believed that the metal-organic protective agent complex is heated to cause thermal decomposition of the metal compound to form metal atoms while maintaining coordination bonding of the organic protective agent to the metal atoms, and then agglomeration of the metal atoms to which the organic protective agent is coordinated, leading to formation of metal nanoparticles that are coated with an organic protective film. The thermal decomposition is preferably performed in the presence of a dispersion medium, and the alcohol described above can be suitably used as the dispersion medium. In addition, the thermal decomposition temperature is to be a temperature at which the surface-modified metal nanoparticles are formed, and when the metal-organic protective agent complex is a silver oxalate-organic protective agent complex, the temperature is, for example, approximately from 80 to 120° C., preferably from 95 to 115° C., and particularly preferably from 100 to 110° C. In terms of preventing the elimination of the surface modification portion of the surface-modified metal nanoparticle, the thermal decomposition is preferably performed at a temperature as low as possible within the above temperature range. The thermal decomposition duration is, for example, approximately from 10 minutes to 5 hours. In addition, the thermal decomposition of the metal-organic protective agent complex is preferably performed in an air atmosphere or in an inert gas atmosphere, such as argon. (Washing Step) The excess organic protective agent, if present after the completion of the thermal decomposition reaction of the metal-organic protective agent complex, is preferably removed by decantation, which may be repeated once or more times as necessary. In addition, the surface-modified metal nanoparticles after the completion of the decantation is preferably subjected to the preparation of the electrically conductive ink described below in a wet state without drying or solidifying in that this can prevent re-agglomeration of the surface-modified metal nanoparticles and maintain high dispersibility. Decantation is performed, for example, by washing the surface-modified metal nanoparticles in a suspended state with a cleaning agent, precipitating the surface-modified metal nanoparticles by centrifugation, and removing the supernatant. The cleaning agent used is preferably one or more types of linear or branched alcohols having from 1 to 4 (preferably from 1 to 2) carbon atoms, such as methanol, ethanol, n-propanol, or isopropanol in terms of achieving good precipitation of the surface-modified metal nanoparticles and efficiently separating and removing the cleaning agent by centrifugation after the washing. In an embodiment of the present invention, the ink used in the inkjet printing (hereinafter, also referred to as “ink for inkjet printing”) can be prepared by mixing the surface-modified metal nanoparticles obtained through the above steps (preferably, surface-modified metal nanoparticles in a wet state), a dispersion medium, and, if necessary, an additive. For the mixing, a commonly known mixing apparatus, such as, for example, a self-rotating stirring defoaming apparatus, a homogenizer, a planetary mixer, a three-roll mill, or a bead mill, can be used. In addition, each component may be mixed at the same time or sequentially. The mixing portion of each component can be appropriately adjusted in the range described below. The content of the surface-modified metal nanoparticles (in terms of metal elements) in the total amount of the ink for inkjet printing (100 wt. %) is, for example, approximately from 35 to 70 wt. %. The lower limit is preferably 40 wt. %, particularly preferably 45 wt. %, most preferably 50 wt. %, and particularly preferably 55 wt. % from the perspective of obtaining a coating film or sintered body with a higher film thickness. The upper limit is preferably 65 wt. %, and particularly preferably 60 wt. % from the perspective of coatability (stability of ejection from the head nozzle when applied by inkjet printing). As the dispersion medium contained in the ink for inkjet printing described above, a common organic solvent can be used without particular limitation, and examples thereof include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, and tetradecane; aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene; and alcohol solvents such as methanol, ethanol, propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, and terpineol. Depending on the desired concentration and viscosity, the type and amount of organic solvent can be appropriately selected. One type of organic solvent used in the dispersion medium can be used alone, or two or more of thereof can be used in combination. The content of the dispersion medium (in terms of metal elements) in the ink for inkjet printing is from 20 to 100 parts by weight, preferably from 30 to 90 parts by weight, more preferably from 40 to 80 parts by weight, even more preferably from 50 to 75 parts by weight, particularly preferably from 55 to 75 parts by weight, and most preferably from 60 to 75 parts by weight per 100 parts by weight of the surface-modified metal nanoparticles. The content of the dispersion medium in the total amount of the ink for inkjet printing (100 wt. %) is, for example, from 20 to 65 wt. %, preferably from 25 to 60 wt. %, more preferably from 30 to 55 wt. %, and most preferably from 30 to 50 wt. %. The ink for inkjet printing contains the dispersion medium in an amount within the range described above and thus has excellent coatability. So, the ink for inkjet printing, when applied by inkjet printing, can well maintain stability of ejection from the nozzle of the head. The viscosity (at 25° C. and shear rate 10 (1/s)) of the ink for inkjet printing is from 1 to 100 mPa·s, for example. The upper limit of the viscosity is preferably 50 mPa·s, particularly preferably 20 mPa·s, and most preferably 15 mPa·s. The lower limit of the viscosity is preferably 2 mPa·s, particularly preferably 3 mPa·s, and most preferably 5 mPa·s. The obtained ink for inkjet printing described above can be used also in a printing process other than inkjet printing, for example, gravure printing, flexographic printing, and the like. The screen printing in an embodiment of the present invention is a method that includes transferring a wiring pattern to the optical member by squeezing the ink containing the electrically conductive substance (extruding the ink with a squeegee) to allow the ink to pass through a screen having an opening corresponding to the wiring pattern. The ink containing the electrically conductive substance used in the screen printing according to an embodiment of the present invention (hereinafter, also referred to as “ink for screen printing”) is not particularly limited as long as it can be used for screen printing. From the perspective of easily forming a wire of a desired width at a target position of the optical member, an ink containing surface-modified metal nanoparticles is preferred, and a silver ink is particularly preferred. The “surface-modified metal nanoparticles” contained in the ink for screen printing described above can be the same as the “surface-modified metal nanoparticles” used in the ink for inkjet printing described above, and can be available from a similar method. The ink for screen printing described above can be prepared by mixing the surface-modified metal nanoparticles described above (preferably, surface-modified metal nanoparticles in a wet state), a solvent, and, if necessary, an additive. For the mixing, a commonly known mixing apparatus, such as, for example, a self-rotating stirring defoaming apparatus, a homogenizer, a planetary mixer, a three-roll mill, or a bead mill, can be used. In addition, each component may be mixed at the same time or sequentially. The mixing portion of each component can be appropriately adjusted in the range described below. The content of the surface-modified metal nanoparticles in the total amount of the ink for screen printing (100 wt. %) is, for example, from 60 to 85 wt. %, and the lower limit is preferably 70 wt. % in that the effect of improving steady contact to the optical member is obtained. The upper limit of the content is preferably 80 wt. % and particularly preferably 75 wt. %. As the solvent contained in the ink for screen printing described above, a common organic solvent can be used without particular limitation, and examples thereof include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, and tetradecane; aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene; and alcohol solvents such as methanol, ethanol, propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, and terpineol. Since clogging of a screen plate caused by volatilization of the solvent is suppressed, and continuous printing is thus possible, at least a terpene solvent is preferably contained in the ink for screen printing. The terpene solvent preferably has a boiling point of 130° C. of higher (for example, from 130 to 300° C., and preferably from 200 to 300° C.). Furthermore, a viscosity (at 20° C.) of the terpene solvent is, for example, from 50 to 250 mPa·s (particularly preferably from 100 to 250 mPa·s, most preferably from 150 to 250 mPa·s), and the use of the viscosity is preferred in that the viscosity of the obtained ink for screen printing can be appropriately increased, and thin lines can be drawn with excellent precision. Note that the viscosity of the solvent is a value at 20° C. and a shear rate of 20 (1/s) measured using a rheometer (trade name “Physica MCR301”, available from Anton Paar). Examples of the terpene solvent include 4-(1′-acetoxy-1′-methylester)-cyclohexanol acetate, 1,2,5,6-tetrahydrobenzyl alcohol, 1,2,5,6-tetrahydrobenzyl acetate, cyclohexyl acetate, 2-methylcyclohexyl acetate; 4-t-butylcyclohexyl acetate, terpineol, dihydroterpineol, dihydroterpinyl acetate, α-terpineol, β-terpineol, γ-terpineol, L-α-terpineol, dihydroterpinyloxyethanol, tarpinyl methyl ether, and dihydroterpinyl methyl ether. One of these solvents can be used alone or two or more in combination. In the present invention, for example, the trade names “Terusolve MTPH”, “Terusolve IPG”, “Terusolve IPG-Ac”, “Terusolve IPG-2Ac”, “Terpineol C” (mixtures of α-terpineol, β-terpineol, and γ-terpineol, boiling point: 218° C.; viscosity: 54 mPa·s), “Terusolve DTO-210”, “Terusolve THA-90”, “Terusolve THA-70” (boiling point: 223° C., viscosity: 198 mPa·s), “Terusolve TOE-100” (all available from Nippon Terpene Chemicals, Inc.), and the like can be used. The solvent used in the ink for screen printing described above may contain one or more types of other solvents in addition to the terpene solvent. Examples of other solvents include glycol ether solvents having a boiling point of 130° C. or higher. Examples of the glycol ether solvent may include compounds represented by Formula (b) below: R11—(O—R13)m—OR12(b) wherein R11and R12are identical or different and represent alkyl or acyl groups, R13represents an alkylene group having from 1 to 6 carbon atoms, and m represents an integer of 1 or greater. Examples of the alkyl groups in R11and R12described above may include linear or branched alkyl groups having from 1 to 10 carbon atoms (preferably, from 1 to 5). Examples of the acyl groups (RCO-groups) in R11and R12described above may include acyl groups (for example, acetyl groups, propionyl groups, butyryl groups, isobutyryl groups, and pivaloyl groups) in which R described above is a linear or branched alkyl group having from 1 to 10 carbon atoms (preferably, from 1 to 5). Among these, a compound in which R11and R12in Formula (b) are groups different from each other (different alkyl groups, different acyl groups, or an alkyl group and an acyl group) is preferred, and a compound in which R11and R12in Formula (b) are alkyl groups different from each other is particularly preferred. A compound including a linear or branched alkyl group having from 4 to 10 carbon atoms (preferably from 4 to 6) and a linear or branched alkyl group having from 1 to 3 carbon atoms is most preferred. Examples of such an alkylene group in R13described above include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. In an embodiment of the present invention, among these, an alkylene group having from 1 to 4 carbon atoms is preferred, and an alkylene group having from 1 to 3 carbon atoms is particularly preferred. An alkylene group having from 2 to 3 carbon atoms is most preferred. m is an integer of 1 or greater and, for example, an integer of from 1 to 8, preferably an integer of from 1 to 3, and particularly preferably an integer of from 2 to 3. The boiling point of the compound represented by Formula (b) is, for example, 130° C. or higher (for example, from 130 to 300° C.), preferably 170° C. or higher, and particularly preferably 200° C. or higher. Examples of the compound represented by Formula (b) include glycol diether, glycol ether acetate, and glycol diacetate such as ethylene glycol methyl ether acetate (boiling point: 145° C.), ethylene glycol-n-butyl ether acetate (boiling point: 188° C.), propylene glycol methyl-n-propyl ether (boiling point: 131° C.); propylene glycol methyl-n-butyl ether (boiling point: 155° C.), propylene glycol methyl isoamyl ether (boiling point: 176° C.), propylene glycol diacetate (boiling point: 190° C.), propylene glycol methyl ether acetate (boiling point: 146° C.), 3-methoxybutyl acetate (boiling point: 171° C.), 1,3-butylene glycol diacetate (boiling point: 232° C.), 1,4-butanediol diacetate (boiling point: 232° C.), 1,6-hexanediol diacetate (boiling point: 260° C.), diethylene glycol dimethyl ether (boiling point: 162° C.), diethylene glycol diethyl ether (boiling point: 189° C.), diethylene glycol dibutyl ether (boiling point: 256° C.), diethylene glycol ethyl methyl ether (boiling point: 176° C.), diethylene glycol isopropyl methyl ether (boiling point: 179° C.), diethylene glycol methyl-n-butyl ether (boiling point: 212° C.), diethylene glycol-n-butyl ether acetate (boiling point: 247° C.), diethylene glycol ethyl ether acetate (boiling point: 218° C.), diethylene glycol butyl ether acetate (boiling point: 246.8° C.), dipropylene glycol methyl-isopentyl ether (boiling point: 227° C.), dipropylene glycol dimethyl ether (boiling point: 175° C.), dipropylene glycol methyl-n-propyl ether (boiling point: 203° C.), dipropylene glycol methyl-n-butyl ether (boiling point: 216° C.), dipropylene glycol methyl cyclopentyl ether (boiling point: 286° C.), dipropylene glycol methyl ether acetate (boiling point: 195° C.), triethylene glycol dimethyl ether (boiling point: 216° C.), triethylene glycol methyl-n-butyl ether (boiling point: 261° C.), tripropylene glycol methyl-n-propyl ether (boiling point: 258° C.), tripropylene glycol dimethyl ether (boiling point: 215° C.), and tetraethylene glycol dimethyl ether (boiling point: 275° C.). One of these solvents can be used alone or two or more in combination. Examples of the glycol ether solvent may include compounds (glycol monoethers) represented by Formula (b′) below: R14—(O—R15)n—OH (b′) wherein R14represents an alkyl group or an aryl group, R15represents an alkylene group having from 1 to 6 carbon atoms, and n represents an integer of 1 or greater. Examples of the alkyl group in R14described above may include linear or branched alkyl groups having from 1 to 10 carbon atoms (preferably, from 1 to 5). Examples of the aryl group may include aryl groups having from 6 to 10 carbon atoms (for example, phenyl groups). Examples of the alkylene group in R15described above include linear or branched alkylene groups such as a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Among these, an alkylene group having from 1 to 4 carbon atoms is preferred, and an alkylene group having from 1 to 3 carbon atoms is particularly preferred. An alkylene group having from 2 to 3 carbon atoms is most preferred. n is an integer of 1 or greater and, for example, an integer of from 1 to 8, preferably an integer of from 1 to 3, and particularly preferably an integer of from 2 to 3. The boiling point of the compound represented by Formula (b′) is, for example, 130° C. or higher (for example, from 130 to 310° C.), preferably from 130 to 250° C., particularly preferably from 130 to 200° C., most preferably from 130 to 180° C., and especially preferably from 140 to 180° C. Examples of the compound represented by Formula (b′) include ethylene glycol monomethyl ether (boiling point: 124° C.), ethylene glycol monoisopropyl ether (boiling point: 141.8° C.), ethylene glycol monobutyl ether (boiling point: 171.2° C.), ethylene glycol monoisobutyl ether (boiling point: 160.5° C.), ethylene glycol monotert-butyl ether (boiling point: 152° C.), ethylene glycol monohexyl ether (boiling point: 208° C.), ethylene glycol mono-2-ethyl hexyl ether (boiling point: 229° C.), ethylene glycol monophenyl ether (boiling point: 244.7° C.), ethylene glycol monobenzyl ether (boiling point: 256° C.), diethylene glycol monomethyl ether (boiling point: 194° C.), diethylene glycol monobutyl ether (=butyl carbitol, boiling point: 230° C.), diethylene glycol monoisobutyl ether (boiling point: 220° C.), diethylene glycol monoisopropyl ether (boiling point: 207° C.), diethylene glycol monopentyl ether (boiling point: 162° C.), diethylene glycol monoisopentyl ether, diethylene glycol monohexyl ether (=hexyl carbitol, boiling point: 259.1° C.), diethylene glycol mono-2-ethyl hexyl ether (boiling point: 272° C.), diethylene glycol monophenyl ether (boiling point: 283° C.), diethylene glycol monobenzyl ether (boiling point: 302° C.), triethylene glycol monomethyl ether (boiling point: 249° C.), triethylene glycol monobutyl ether (boiling point: 271.2° C.), propylene glycol monoethyl ether (boiling point: 132.8° C.), propylene glycol monopropyl ether (boiling point: 149° C.), propylene glycol monobutyl ether (boiling point: 170° C.), dipropylene glycol monomethyl ether (boiling point: 188° C.), and 3-methoxy-1-butanol (boiling point: 158° C.). One of these solvents can be used alone or two or more in combination. The content of the terpene solvent in the total amount of the ink for screen printing (100 wt. %) is, for example, from 5 to 30 wt. %, and the lower limit is preferably 10 wt. %, and particularly preferably 14 wt. %. The upper limit of the content is preferably 25 wt. % and particularly preferably 18 wt. %. The terpene solvent contained in the range described above can provide the effect of suppressing bleeding and improving the drawing accuracy of thin lines and the effect of improving the continuous printing properties. The content of the compound represented by Formula (b) in the total amount of the ink for screen printing (100 wt. %) is, for example, from 0.5 to 5 wt. %, and the lower limit is preferably 1.6 wt. %. The upper limit of the content is preferably 3 wt. % and particularly preferably 2 wt. %. The blending of the compound represented by Formula (b) in an amount within the above range can impart thixotropy, make the edge of a drawing par sharper, and improve the printing accuracy. In addition, the effect of improving continuous printing properties can also be obtained. Additionally, the ink for screen printing can contain the compound represented by Formula (b′) in an amount of 10 wt. % or less (from 5 to 10 wt. %), and preferably 8.5 wt. % or less of the total amount of the ink. The ink for screen printing described above may contain, as a solvent having a boiling point of 130° C. or higher, one or more types of ethyl lactate acetate (boiling point: 181° C.), tetrahydrofurfuryl acetate (boiling point: 195° C.), tetrahydrofurfuryl alcohol (boiling point: 176° C.), ethylene glycol (boiling point: 197° C.), and the like, in addition to the compound represented by Formula (b) above and the compound represented by Formula (b′) above. However, the content of such other solvents having a boiling point of 130° C. or higher is 30 wt. % or less, preferably 20 wt. % or less, particularly preferably 15 wt. % or less, most preferably 10 wt. % or less, even more preferably 5 wt. % or less, and especially preferably 1 wt. % or less of the total amount of the solvent contained in the ink for screen printing. Furthermore, the ink for screen printing may also contain a solvent having a boiling point of lower than 130° C. [for example, ethylene glycol dimethyl ether (boiling point: 85° C.), propylene glycol monomethyl ether (boiling point: 120° C.), and propylene glycol monomethyl ether (boiling point: 97° C.)]. The content of the solvent having a boiling point of lower than 130° C. (total amount, if two or more types are contained) in the total amount of the ink for screen printing (100 wt. %) is preferably 20 wt. % or less, more preferably 10 wt. % or less, particularly preferably 5 wt. % or less, and most preferably 1 wt. % or less. In the above ink for screen printing, when the content of the solvent having a boiling point of lower than 130° C. is suppressed to the range described above, clogging of the screen plate caused by volatilization of the solvent can be suppressed, and continuous printing is thus easily possible. One type of solvent used in the above ink for screen printing can be used alone, or two or more of thereof can be used in combination. The ink for screen printing described above can contain, in addition to the above components, an additive such as a binder resin, a surface energy modifier, a plasticizer, a leveling agent, an antifoaming agent, or a tackifier, as necessary. Among these, a binder resin is preferably contained in that the effect of improving the steady contact and flexibility of a sintered body to the optical member can be obtained, the sintered body being obtained by applying (or printing) the ink for screen printing onto the optical member and then sintering. Examples of the binder resin include vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, polyester resins, acrylic resins, and cellulosic resins. One of these solvents can be used alone or two or more in combination. Of these, a cellulosic resin is preferably used, and commercially available products such as the trade names “ETHOCEL std.200” and “ETHOCEL std.300” (both available from The Dow Chemical Company) can be used. The content of the binder resin (for example, cellulosic resin) is, for example, approximately from 0.5 to 5.0 wt. %, and preferably from 1.0 to 3.0 wt. % of the total amount of the ink for screen printing. The viscosity (at 25° C., shear rate 10 (1/s)) of the ink for screen printing is, for example, 60 Pa·s or greater, preferably 70 Pa·s or greater, more preferably 80 Pa·s or greater, even more preferably 90 Pa·s or greater, even more preferably 100 Pa·s or greater, and particularly preferably 150 Pa·s or greater. The upper limit of the viscosity is, for example, approximately 500 Pa·s, preferably 450 Pa·s, particularly preferably 400 Pa·s, and most preferably 350 Pa·s. The viscosity (at 25° C. and shear rate 100 (1/s)) of the above ink for screen printing is, for example, from 10 to 100 Pa·s, and the upper limit thereof is preferably 80 Pa·s, particularly preferably 60 Pa·s, most preferably 50 mPa·s, and especially preferably 40 Pa·s. The lower limit of the viscosity is preferably 15 Pa·s, particularly preferably 20 Pa·s, most preferably 25 Pa·s, and especially preferably 30 Pa·s. The ink for screen printing preferably has thixotropy, and the TI value at 25° C. (viscosity at a shear rate of 10 (1/s)/viscosity at a shear rate of 100 (1/s)) is in a range of for example from 3.0 to 10.0, preferably from 3.5 to 7.0, particularly preferably from 4.0 to 6.5, most preferably from 4.5 to 6.3, and especially preferably from 4.8 to 6.2. As the ink for screen printing, a commercially available product, for example, a silver paste ink (product name: NP-2910D1) available from Noritake Co., Ltd. can also be used. The method for forming the wire on the optical member according to an embodiment of the present invention includes applying the ink to the optical member by a printing process, and sintering. In the optical member according to an embodiment of the present invention, a known or commonly used surface treatment such as roughening treatment, adhesion-facilitating treatment, antistatic treatment, sand blast treatment (sand mat treatment), corona discharge treatment, plasma treatment, excimer treatment, chemical etching treatment, water mat treatment, flame treatment, acid treatment, alkali treatment, oxidation treatment, ultraviolet irradiation treatment, or silane coupling agent treatment may be applied to the surface on which the wire is formed. The non-optical element region is preferred as the surface to be surface-treated. On the other hand, the optical element region may be surface-treated or not surface-treated. The thickness of the coating film obtained by applying the ink is preferably in a range such that the thickness of the sintered body obtained by sintering the coating film is, for example, from 0.1 to 5 μm (preferably, 0.5 to 2 μm). The width of the coating film obtained by applying the above ink is not particularly limited, and can be appropriately selected according to the shape, size, and the like of the optical member, and the width of the sintered body obtained by sintering the coating film is, for example, 200 μm or less (for example, from 1 to 200 μm), and preferably in a range of from 10 to 100 μm. By sintering the coating film formed above, the coating film can be formed into an electrically conductive wire (sintered body). The sintering temperature is, for example, 150° C. or lower (the lower limit of the sintering temperature is, for example, 60° C., and is more preferably 100° C. in that the coating film can be sintered in a short period of time), particularly preferably 130° C. or lower, and most preferably 120° C. or lower. The sintering time is, for example, from 0.5 to 3 hours, preferably from 0.5 to 2 hours, and particularly preferably from 0.5 to 1 hour. The width of the wire formed on the optical member according to an embodiment of the present invention is not particularly limited, and can be appropriately selected according to the shape, size, and the like of the optical member, and is, for example, 200 μm or less (for example, from 1 to 200 μm), and preferably in a range of from 10 to 100 μm. By setting the width of the wire to be within this range, it becomes easier to ensure conduction. In the optical member according to an embodiment of the present invention, the wire containing the electrically conductive substance is formed, and the position thereof is not particularly limited, but when the optical member includes the optical element region and the non-optical element region described above, the wire is preferably formed in the non-optical element region for the purpose of not impairing the illumination of the laser light and the structural light that are emitted from the surface emitting laser light source and controlled by the optical element. When the optical member according to an embodiment of the present invention has a substrate shape, the wire containing the electrically conductive substance may be formed on only one side, or may be formed on both sides. When the ink containing the electrically conductive substance is applied to the optical member by the printing process to form the wire, the optical member is preferably an optical element array in which two or more optical elements are arranged two-dimensionally. Specifically, it is preferable that two or more optical element regions be arranged two-dimensionally, and preferably connected via a non-optical element region. By employing the optical element array, the wire containing the electrically conductive substance can be formed collectively with respect to each of the optical elements, and therefore production efficiency is greatly improved. The optical element array can be easily available from using a mold having a molding surface in which an inverted shape corresponding to two or more optical elements arranged two-dimensionally on the optical element array is arranged two-dimensionally as the mold for manufacturing the optical member described above. After the wire is applied to each of the optical elements arranged on the optical element array, the optical member according to an embodiment of the present invention can be obtained by singulating each optical element. Specifically, by cutting the non-optical element region connecting the two or more optical element regions, the optical member according to an embodiment of the present invention including the singulated optical element regions can be obtained. The process of singulating the optical element array into individual optical elements is not particularly limited, and well-known and commonly used means can be employed. Among others, a blade rotating at high speed is preferably used. In cutting using a blade rotating at high speed, the rotation speed of the blade is, for example, approximately from 10000 to 50000 rpm. Furthermore, cutting the array of optical elements using a blade rotating at high speed may generate frictional heat. Thus, it is preferred to cut the array of optical elements while cooling, in terms of being able to suppress deformation of the optical elements and reduction in optical properties due to the frictional heat. Optical elements obtained by cutting the optical element array at the non-optical element region includes an optical element region and a non-optical element region on the periphery thereof. FIG.1, diagrams (a), (b), and (c) are schematic diagrams illustrating an example of a preferred embodiment of the optical member of the present invention.FIG.1, diagram (a) is a perspective view,FIG.1, diagram (b) is a top view, andFIG.1, diagram (c) is a side view. The optical member10inFIG.1includes an optical element region11in which an optical element is formed in a lower surface central portion of the optical member10, and also includes a non-optical element region12in which no optical element is formed on the periphery of the optical element region11Note that no optical element is formed on the upper surface of the optical member10, but regions corresponding to the optical element region11and the non-optical element region12, when viewed from the upper surface, are defined as the optical element region11and the non-optical element region12, respectively. The wire13is formed in the non-optical element region12on the upper surface of the optical member10in such a manner that it surrounds the periphery of the optical element region11. By arranging the wire13in this manner, in a case where damage such as cracking occurs in the optical element region11of the optical member10, the wire13breaks and fails to be conductive. Therefore, by monitoring the conducting state of the wire13, damage such as cracking, in particular, spanning the optical element region11, of the optical member10can be detected. On both ends of the wire13, a conduction detection mechanism connection portion14that connects to a conduction detection mechanism described below is formed. InFIG.1, one side of the optical member10(square on the upper surface) is approximately 2 mm, one side of the optical element region (square) is approximately 1 mm, the thickness is approximately 300 μm, the total light transmittance is approximately 90%, and the haze is approximately 0.5%. FIG.2, diagrams (a) and (b) are schematic diagrams illustrating another example of the preferred embodiment of the optical member of the present invention.FIG.2, diagram (a) is a top view, andFIG.2, diagram (b) is a cross-sectional view taken along X-X′. The optical member20inFIG.2includes an optical element region11in which an optical element is formed in a lower surface central portion of the optical member20, and also includes a non-optical element region12in which no optical element is formed on the periphery of the optical element region11The wire13is formed in the non-optical element region12on the lower surface of the optical member20in such a manner that it surrounds the periphery of the optical element region11. In a case where cracking or the like occurs in the optical element region11of the optical member20, the wire13breaks and fails to be conductive. Therefore, similarly toFIG.1, by monitoring the conducting state of the wire13, damage such as cracking, in particular, spanning the optical element region11, of the optical member10can be detected. On both ends of the wire13, a conduction detection mechanism connection portion14that connects to a conduction detection mechanism described below is formed. Additionally, the conduction detection mechanism connection portion14is formed on a tip end of a protrusion15protruding from the lower surface of the optical member20. By forming the conduction detection mechanism connection portion14on the tip end of the protrusion15, it is easily connected to the conduction detection mechanism, as illustrated inFIG.4described below. [Surface Emitting Laser Light Source] A laser module including the optical member according to an embodiment of the present invention includes a surface emitting laser light source as a light source. The surface emitting laser light source used in an embodiment of the present invention is not particularly limited, includes a Vertical Cavity Surface Emitting Laser (VCSEL) and a Vertical External Cavity Surface Emitting Laser (VECSEL) with a cavity external thereto, and is preferably VCSEL because it is commonly used in 3D sensing and low in cost. The laser light emitted by the surface emitting laser light source may be visible light or ultraviolet light or infrared rays, but near infrared radiation having a wavelength of from 750 to 2500 nm, which is highly safe and often used in 3D sensing, is preferred. In particular, near infrared radiation having a wavelength of from 800 to 1000 nm which is not susceptible to environmental light such as sunlight is particularly preferred. The output light intensity is not particularly limited and can be selected appropriately according to the application and purpose. [Laser Module] The laser module according to an embodiment of the present invention includes the optical member according to an embodiment of the present invention and the surface emitting laser light source described above. Embodiments of the laser module according to an embodiment of the present invention are not particularly limited as long as it is arranged in such a manner that the laser light emitted from the surface emitting laser light source passes through the optical member (preferably, optical element region formed in the optical member). When the optical member includes an optical element, the laser light passing through the optical element region is controlled and shaped into uniform light, structural light, or the like. FIG.3, diagrams (a) and (b) are schematic views illustrating an example of a preferred embodiment of the laser module of the present invention.FIG.3, diagram (a) is a perspective view, andFIG.3, diagram (b) is a cross-sectional view taken along Y-Y′ and Z-Z′. In a laser module30ofFIG.3, a surface emitting laser light source33such as VCSEL is arranged on a center upper portion of a substrate31, and an optical member10is further arranged above the substrate31via a spacer32. An optical element region11is arranged in the center portion of the lower surface of the optical member10, and is in contact with the spacer32at an outer edge portion of a non-optical element region12in the lower surface. A wire13is formed in the non-optical element region12on an outer periphery of the upper surface of the optical member10, and conduction detection mechanism connection portions14are formed on both ends of the wire13, which connect to a conduction detection mechanism described below. Laser light34emitted by the surface emitting laser light source33passes through an optical element such as a microlens array or an optical diffraction grating in the optical element region11and is emitted from the laser module30as laser light35controlled and shaped into uniform or structural light. In the event of cracking or other damage spanning the optical element region11of the optical member10, the optical element in the optical element region11is unable to function normally. The laser light34is not sufficiently diffused in the optical element region11, and is radiated from the laser module30. Thus, defects or erroneous actuation may be caused in the laser device mounted with the laser module30. In a case where damage such as cracking occurs in the optical element region11of the optical member10, the wire13formed surrounding the optical element region11breaks and fails to be conductive. Accordingly, damage to the optical member10can be detected by monitoring the conducting state of the wire13. In addition to the optical member and the surface emitting laser, the laser module according to an embodiment of the present invention preferably further includes a conduction detection mechanism that detects a conducting state of the wire containing the electrically conductive substance, which is included in the optical member. The form of the conduction detection mechanism is not particularly limited as long as the conduction detection mechanism is capable of detecting the conducting state of the wire, but the form is preferably an aspect having an electrode connected to both ends of the wire. FIG.4is a schematic cross-sectional view illustrating another example of the preferred embodiment of the laser module of the present invention. The laser module40inFIG.4has a configuration in which the optical member20inFIG.2is mounted on a conduction detection mechanism41, and, further, a substrate31and a surface emitting laser light source33are arranged in the lower portion of the optical member20. The conduction detection mechanism41includes a retainer43for holding the optical member20and an electrode42laminated on the retainer43. The electrode42is not particularly limited as long as it is conductive, but is preferably made of copper. The retainer43has a protrusion43aon an upper periphery thereof, and the optical member20is housed inside the retainer43. The electrode42is stacked on the inner surface and the upper surface of the retainer43, and the upper end of the electrode42is in contact with the conduction detection mechanism connection portion14of the optical member20and retains the optical member20from below. The lower end of the electrode42is connected with a conduction detector (not illustrated) with the other electrode to monitor the conducting state of the wire13. When damage such as cracking occurs in the optical member20, damage to the optical member20can be detected by detecting that the wire13breaks and fails to be conductive. The laser module according to an embodiment of the present invention can be suitably used as a laser module for generating depth information in 3D sensing. Examples of the method for generating depth information include a Time of Flight (TOF) method, a structured light method, a stereo matching method, and a Structure from Motion (SfM) method. The TOF method is a method of irradiating a target space with near infrared radiation, receiving reflected light in an object in the target space, measuring a time from irradiation with the near infrared radiation until receiving the reflected light, and determining a distance to the object in the target space based on the time. Furthermore, the structured light method is a method of projecting a predetermined projection pattern of near infrared radiation on an object present in a target space, and detecting a shape (depth) of the object present in the target space on the basis of the state of deformation of the projection pattern. Furthermore, the stereo matching method is a method of determining a distance to a subject based on a parallax between two captured images of the subject captured from different positions. Furthermore, the SfM method is a method of performing depth detection by calculating a relationship between images, such as registration of feature points, using a plurality of captured images captured from different angles, and performing optimization. [Laser Device] The laser device according to an embodiment of the present invention includes the laser module according to an embodiment of the present invention. The laser device according to an embodiment of the present invention includes the laser module according to an embodiment of the present invention, and thus can easily detect damage such as cracking, peeling, and the like of the optical member used in the laser module. Therefore, defects of the laser module caused by damage to the optical member and injuries caused by erroneous actuation can be prevented. Accordingly, the laser device according to an embodiment of the present invention can be suitably used in 3D sensing applications suited to such characteristics. For example, in face authentication of a smartphone, attention can be attracted by sending an error message to the user, or the laser light itself is not emitted, thereby preventing the user's eyes from being directly irradiated with the laser light and reducing a risk of blindness and the like. Also, in automatic driving of an automobile, defects in a 3D sensing system mounted with the laser module are detected, and error messages or the like are sent to the driver, thereby making it possible to prevent accidents caused by erroneous actuation. It can also be suitably used in any application using 3D sensing, such as a recognition camera for 3D mapping, a gesture recognition controller for a gaming device, automatic driving of an automobile, and machine vision in a plant. EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these examples. Manufacture Example 1 (Manufacture of Optical Member not Provided with Wire) An epoxy resin (CELVENUS106; available from Daicel Co., Ltd.) (5 g) was added dropwise onto a disk-shaped silicone resin substrate in which 9×9 inversion patterns of diffractive optical elements were arranged in one section (2.5 mm in length×2.5 mm in width) with a diameter of 100 mm. The mold was closed, with the thickness of a flat silicone resin substrate having the same size being approximately 0.3 mm. UV irradiation was performed at 100 mW/cm2×30 seconds. When the upper and lower silicone resin substrates were removed, an optical member in which 9×9 diffractive optical elements were arranged in one disk-shaped section (2.5 mm in length×2.5 mm in width) was obtained as a cured product of the epoxy resin. Manufacture Example 2 (Manufacture of Optical Member not Provided with Wire) An epoxy resin (CELVENUS106; available from Daicel Co., Ltd.) (5 g) was added dropwise onto a disk-shaped silicone resin substrate in which 9×9 inversion patterns of diffractive optical elements were arranged in one section (2.5 mm in length×2.5 mm in width) with a diameter of 100 mm. The mold was closed, with the thickness of a flat glass substrate having the same size being approximately 0.3 mm. UV irradiation was performed at 100 mW/cm2×30 seconds. When the silicone resin substrate on the lower mold was removed, an optical member was obtained in which a cured product layer of the epoxy resin in which 9×9 diffractive optical elements were arranged in one section (2.5 mm in length×horizontal 2.5 mm) was laminated on the glass substrate. Manufacture Example 3 (Preparation of Surface-Modified Silver Nanoparticles) Formation of Complex Silver oxalate (molecular weight: 303.78) was obtained from silver nitrate (available from Wako Pure Chemical Industries, Ltd.) and oxalic acid dihydrate (available from Wako Pure Chemical Industries, Ltd.). Then, 20.0 g (65.8 mmol) of the silver oxalate was charged to a 500-mL flask, 30.0 g of n-butanol was added to this, and an n-butanol slurry of silver oxalate was prepared. To this slurry, an amine mixture liquid of 57.8 g (790.1 mmol) of n-butylamine (a molecular weight of 73.14, available from Daicel Corporation), 40.0 g (395.0 mmol) of n-hexylamine (a molecular weight of 101.19, available from Tokyo Chemical Industry Co., Ltd.), 38.3 g (296.3 mmol) of n-octylamine (a molecular weight of 129.25, trade designation “FARMIN 08D”, available from Kao Corporation), 18.3 g (98.8 mmol) of n-dodecylamine (a molecular weight of 185.35, trade designation “FARMIN 20D”, available from Kao Corporation), and 40.4 g (395.0 mmol) of N,N-dimethyl-1,3-propanediamine (a molecular weight of 102.18, available from Koei Chemical Co., Ltd.) was added dropwise at 30° C. After the dropwise addition, the mixture was stirred at 30° C. for 2 hours to allow a complex forming reaction between silver oxalate and the amines to proceeded, and a white material (silver oxalate-amine complex) was obtained. Thermal Decomposition After the formation of the silver oxalate-amine complex, the reaction solution temperature was raised from 30° C. to approximately 105° C. (from 103 to 108° C.), then the silver oxalate-amine complex was thermally decomposed by heating for 1 hour in a state of maintaining the temperature, and a dark blue suspension in which surface-modified silver nanoparticles were suspended in the amine mixture liquid was obtained. Washing After cooling, 200 g of methanol was added to the resulting suspension, and the mixture was stirred. Then, the surface-modified silver nanoparticles were precipitated by centrifugation, and the supernatant was removed. Then, 60 g of methanol was added again, and the mixture was stirred, then the surface-modified silver nanoparticles were precipitated by centrifugation, and the supernatant was removed. Surface-modified silver nanoparticles in a wet state were thus obtained. Manufacture Example 4 (Preparation of Silver Ink for Inkjet Printing) The dispersion medium was mixed with the surface-modified silver nanoparticles obtained in Manufacture Example 3 to obtain a black brown silver ink for inkjet printing. Example 1 (Inkjet Printing) The silver ink for inkjet printing obtained in Manufacture Example 4 was filled into an inkjet printer, and a wire was printed on one side of the disk-shaped optical member obtained in Manufacture Example 1 in such a manner that it surrounded the periphery of each of the diffractive optical elements in which 9×9 sections (2.5 mm in length×2.5 mm in width for each section) were arranged. The optical member on which the wire was printed was sintered using a hot plate, and an optical member was obtained in which a wire having a thickness of approximately 1 μm and a width of approximately 50 μm was arranged in an array. The optical member having the wire obtained in an array was singulated into an optical member having each of the wires using a dicing apparatus (DAD3350, available from DICSO) mounted with a dicing blade (available from DISCO) having a thickness of 0.1 μm. Example 2 (Inkjet Printing) The silver ink for inkjet printing obtained in Manufacture Example 4 was filled into an inkjet printer, and a wire was printed on the glass substrate surface of the disk-shaped optical member obtained in Manufacture Example 2 in such a manner that it surrounded the periphery of each of the diffractive optical elements in which 9×9 sections (2.5 mm in length×2.5 mm in width for each section) were arranged. The optical member on which the wire was printed was sintered using a hot plate, and an optical member was obtained in which a wire having a thickness of approximately 1 μm and a width of approximately 50 μm was arranged in an array. The optical member having the wire obtained in an array was singulated into an optical member having each of the wires using a dicing apparatus (DAD3350, available from DICSO) mounted with a dicing blade (available from DISCO) having a thickness of 0.1 μm. Example 3 (Screen Printing) With silver paste ink (product name: NP-2910D1), available from Noritake Co., Ltd., a wire was printed on the glass surface of the disk-shaped optical member obtained in Manufacture Example 2 at 25° C. using a screen printing apparatus (LS-150TV, available from NEWLONG SEIMITSU KOGYO Co., Ltd.) in such a manner that it surrounded the periphery of each of the diffractive optical elements in which 9×9 sections (2.5 mm in length×2.5 mm in width for each section) were arranged. The optical member on which the wire was printed was sintered using a hot plate, and an optical member was obtained in which a wire having a thickness of approximately 1 μm and a width of approximately 50 μm was arranged in an array. The optical member having the wire obtained in an array was singulated into an optical member having each of the wires using a dicing apparatus (DAD3350, available from DICSO) mounted with a dicing blade (available from DISCO) having a thickness of 0.1 μm. Example 4 (Screen Printing) With silver paste ink (product name: NP-2910D1), available from Noritake Co., Ltd., a wire was printed on one side of the disk-shaped optical member obtained in Manufacture Example 1 at 25° C. using a screen printing apparatus (LS-150TV, available from NEWLONG SEIMITSU KOGYO Co., Ltd.) in such a manner that it surrounded the periphery of each of the diffractive optical elements in which 9×9 sections (2.5 mm in length×2.5 mm in width for each section) were arranged. The optical member on which the wire was printed was sintered using a hot plate, and an optical member was obtained in which a wire having a thickness of approximately 1 μm and a width of approximately 50 μm was arranged in an array. The optical member having the wire obtained in an array was singulated into an optical member having each of the wires using a dicing apparatus (DAD3350, available from DICSO) mounted with a dicing blade (available from DISCO) having a thickness of 0.1 μm. Evaluation Test (Reflow Heat Resistance Test) The conduction of the wire was confirmed by connecting the tester to both ends of the wire of the singulated optical member obtained in Example 1. The resistance value was 4.4Ω. Thereafter, the optical member was placed in a simple reflow furnace (available from Shinapex Co., Ltd.), and a heat resistance test based on the reflow temperature profile (maximum temperature: 260° C.) prescribed in JEDEC standard was applied three times sequentially, and then the conduction of the wire of the optical member after heat treatment by the reflow furnace was checked. The resistance value was 2.0Ω. As a result, it was confirmed that no damage such as cracks occurred in the optical member of Example 1 even after heat treatment using the reflow furnace. Variations of embodiments of the present invention described above are additionally described below.[1] An optical member for use in a laser module including a surface emitting laser light source, the optical member including a wire containing an electrically conductive substance.[2] The optical member according to [1], wherein the optical member is formed from at least one type selected from the group consisting of plastic and inorganic glass.[3] The optical member according to [1] or [2], wherein the optical member is plastic or a laminate of plastic and inorganic glass.[4] The optical member according to [3], wherein the laminate is a laminate in which a plastic layer on which an optical element is formed is laminated on one side of a substrate made of flat inorganic glass.[5] The optical member according to [3] or [4], wherein the plastic is a cured product of a curable epoxy resin composition.[6] The optical member according to [5], wherein the curable epoxy resin composition contains a polyfunctional alicyclic epoxy compound.[7] The optical member according to [6], wherein the polyfunctional alicyclic epoxy compound includes at least one type of compound selected from the group consisting of (i) to (iii) below:a compound (i) including an epoxy group (an alicyclic epoxy group) constituted of two adjacent carbon atoms and an oxygen atom that constitute an alicyclic ring;a compound (ii) including an epoxy group directly bonded to an alicyclic ring with a single bond; and a compound (iii) including an alicyclic ring and a glycidyl group.[8] The optical member according to [7], wherein the compound (i) having an alicyclic epoxy group includes a compound represented by Formula (i) below: wherein X represents a single bond or a linking group (a divalent group having one or more atoms; and a substituent (for example, such as an alkyl group) may be bonded to a cyclohexene oxide group.[9] The optical member according to [8], wherein the compound (i) includes (3,4,3′,4′-diepoxy)bicyclohexyl.[10] The optical member according to any one of [1] to [9], wherein the optical member includes an optical element (for example, a diffractive optical element, a microlens array, a prism, a polarizing plate, or the like).[11] The optical member of any one of [1] to [10], wherein the optical member includes at least one type of optical element selected from the group consisting of a diffractive optical element and a microlens array.[12] The optical member according to [10] or [11], wherein the optical member has a substrate shape and includes a region in which an optical element is formed (hereinafter, also referred to as “optical element region”) and a region in which no optical element is formed (hereinafter, also referred to as “non-optical element region”).[13] The optical member according to [12], wherein the optical element region is formed in a center portion of the substrate of the optical member, and the non-optical element region is provided on the periphery of the optical element region (outer periphery of the substrate of the optical member).[14] The optical member according to [12] or [13], wherein the wire is formed in the non-optical element region of the optical member.[15] The optical member according to [13] or [14], wherein the wire is formed in the non-optical element region of the optical member in such a manner that it surrounds the periphery of the optical element region.[16] The optical member according to any one of [1] to [15], wherein the wire has a width of not greater than 200 μm (for example, from 1 to 200 μm, and preferably from 10 to 100 μm).[17] The optical member according to any one of [1] to [16], wherein the electrically conductive substance includes at least one type selected from the group consisting of a metal, a metal oxide, an electrically conductive polymer, and an electrically conductive carbon-based substance.[18] The optical member according to any one of [1] to [17], wherein the electrically conductive substance includes a metal (e.g., gold, silver, copper, chromium, nickel, palladium, aluminum, iron, platinum, molybdenum, tungsten, zinc, lead, cobalt, titanium, zirconium, indium, rhodium, ruthenium, and alloys thereof).[19] The optical member according to any one of [1] to [18], wherein the electrically conductive substance includes silver.[20] A method for manufacturing the optical member described in any one of [1] to [19], the method including:applying an ink containing an electrically conductive substance to an optical member by a printing process to form the wire.[21] The method for manufacturing the optical member according to [20], wherein the printing process includes inkjet printing or screen printing.[22] The method for manufacturing the optical member according to [20] or [21], wherein the ink containing the electrically conductive substance is an ink containing surface-modified metal nanoparticles having a configuration in which surfaces of the metal nanoparticles are coated with an organic protective agent (hereinafter, also referred to as “surface-modified metal nanoparticles”).[23] The method for manufacturing the optical member according to [22], wherein the surface-modified metal nanoparticles each consist of a metal nanoparticle portion and a surface modification portion that covers the metal nanoparticle portion, and the proportion of the surface modification portion is from 1 to 20 wt. % (preferably, from 1 to 10 wt. %) of the weight of the metal nanoparticle portion.[24] The method for manufacturing the optical member according to [23], wherein the metal nanoparticle portion has an average primary particle diameter of from 0.5 to 100 nm (preferably from 0.5 to 80 nm, more preferably from 1 to 70 nm, and even more preferably from 1 to 60 nm).[25] The method for manufacturing the optical member according to [23] or [24], wherein the metal that constitutes the metal nanoparticle portion is at least one type (preferably silver) selected from the group consisting of gold, silver, copper, nickel, aluminum, rhodium, cobalt, and ruthenium.[26] The method for manufacturing the optical member according to any one of [22] to [25], wherein the organic protective agent that constitutes the surface modification portion of the surface-modified metal nanoparticle includes a compound having from 4 to 18 carbon atoms and having an amino group (an amine having from 4 to 18 carbon atoms).[27] The method for manufacturing the optical member according to any one of [22] to [26], wherein the organic protective agent that constitutes the surface modification portion of the surface-modified metal nanoparticle contains, as amines, a monoamine (1) having 6 or more carbon atoms in total, and a monoamine (2) having 5 or less carbon atoms in total and/or a diamine (3) having 8 or less carbon atoms in total.[28] The method for manufacturing the optical member according to any one of [20] to [27], wherein the optical member is an optical element array in which two or more optical elements are arranged two-dimensionally.[29] The method for manufacturing the optical member according to [28], further including singulating the optical element array into the two or more optical elements by dicing.[30] A laser module including the optical member described in any one of [1] to [19] and a surface emitting laser light source.[31] The laser module according to [30], wherein laser light emitted by the surface emitting laser light source includes near infrared radiation having a wavelength of from 800 to 1000 nm.[32] The laser module according to [30] or [31], further including a conduction detection mechanism for detecting a conducting state of the wire containing the electrically conductive substance, which is included in the optical member.[33] The laser module according to [32], wherein the conduction detection mechanism includes an electrode connected to both ends of the wire.[34] The laser module according to any one of [30] to [33], which is a laser module for generating depth information in 3D sensing.[35] The laser module according to [34], wherein a method for generating depth information includes at least one type selected from the group consisting of a Time of Flight (TOF) method, a structured light method, a stereo matching method, and a Structure from Motion (SfM) method.[36] A laser device including the laser module described in any one of [30] to [35].[37] The laser device according to [36], which is used in 3D sensing selected from the group consisting of face authentication of a smartphone, automatic driving of an automobile, recognition cameras for 3D mapping, gesture recognition controllers for gaming devices, and machine vision in a plant. INDUSTRIAL APPLICABILITY The optical member, laser module including the optical member, and laser device of the present invention can be suitably used in 3D sensing such as face authentication of a smartphone, automatic driving of an automobile, recognition cameras for 3D mapping, gesture recognition controllers for gaming devices, and machine vision in a plant. REFERENCE SIGNS LIST 10,20: Optical member11: Optical element region12: Non-optical element region13: Wire containing electrically conductive substance14: Conduction detection mechanism connection portion30,40: Laser module31: Substrate32: Spacer33: Surface emitting laser light source34: Laser light emitted from surface emitting laser light source35: Laser light emitted from laser module41: Conduction detection mechanism42: Electrode43: Retainer for optical member | 121,764 |
11862937 | DETAILED DESCRIPTION OF THE INVENTION According to the present invention, techniques related generally to optical devices are provided. More particularly, the present invention provides a method and device for emitting electromagnetic radiation using semipolar or non-polar gallium containing substrates such as GaN, MN, InN, InGaN, AlGaN, and AlInGaN, and others. Merely by way of example the invention can be applied to the non-polar m-plane or to the semipolar (11-22), (30-31), (30-3-1), (20-21), (20-2-1), (30-32), or (30-3-2), or offcuts thereof. Merely by way of example, the invention can be applied to optical devices, lasers, light emitting diodes, solar cells, photoelectrochemical water splitting and hydrogen generation, photodetectors, integrated circuits, and transistors, among other devices. In a specific embodiment, the present laser device can be employed in either a semipolar or non-polar gallium containing substrate, as described below. Laser diodes according to this invention can offer improved efficiency, cost, temperature sensitivity, and ruggedness over lasers based on SHG technology. Moreover, laser diodes according to this invention can provide an output with a spectral linewidth of 0.5 to 2 nm, which is advantageous in display applications where speckle must be considered. FIG.1Ais a simplified perspective view of a laser device100fabricated on a semipolar substrate according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims herein. One of ordinary skill in the art would recognize other variations, modifications, and alternatives. As shown, the optical device includes a gallium nitride substrate member101having a semipolar or non-polar crystalline surface region. In a specific embodiment, the gallium nitride substrate member is a bulk GaN substrate characterized by having a semipolar or non-polar crystalline surface region, but can be others. In a specific embodiment, the bulk nitride GaN substrate comprises nitrogen and has a surface dislocation density below 107cm−2or 105cm−2. The nitride crystal or wafer may comprise AlxInyGa1-x-yN, where 0≤x, y, x+y≤1. In one specific embodiment, the nitride crystal comprises GaN. In one or more embodiments, the GaN substrate has threading dislocations, at a concentration between about 105cm−2and about 10 cm−2, in a direction that is substantially orthogonal or oblique with respect to the surface. As a consequence of the orthogonal or oblique orientation of the dislocations, the surface dislocation density is below about 107cm−2or below about 105cm−2. In a specific embodiment, the device can be fabricated on a slightly off-cut semipolar substrate as described in U.S. application Ser. No. 12/749,466, which claims priority to U.S. Provisional No. 61/164,409 filed on Mar. 28, 2009, commonly assigned, and hereby incorporated by reference herein. In a specific embodiment on semipolar GaN, the device has a laser stripe region formed overlying a portion of the semi polar crystalline orientation surface region. In a specific semipolar GaN embodiment, the laser stripe region is characterized by a cavity orientation is substantially parallel to the m-direction. In a specific embodiment, the laser strip region has a first end107and a second end109. In a specific embodiment on nonpolar GaN, the device has a laser stripe region formed overlying a portion of the semi or non-polar crystalline orientation surface region, as illustrated byFIG.1B. The laser stripe region is characterized by a cavity orientation which is substantially parallel to the c-direction. The laser strip region has a first end and a second end. Typically, the non-polar crystalline orientation is configured on an m-plane, which leads to polarization ratios parallel to the a-direction. In some embodiments, the m-plane is the (10-10) family. Of course, the cavity orientation can also be substantially parallel to the a-direction as well. In the specific nonpolar GaN embodiment having the cavity orientation substantially parallel to the c-direction is further described in “Laser Device and Method Using Slightly Miscut Non-Polar GaN Substrates,” in the names of Raring, James W. and Pfister, Nick listed as U.S. application Ser. No. 12/759,273, which claims priority to U.S. Provisional Ser. No. 61/168,926 filed on Apr. 13, 2009, commonly assigned, and hereby incorporated by reference for all purposes. In a preferred semipolar embodiment, the device has a first cleaved semipolar facet provided on the first end of the laser stripe region and a second cleaved semipolar facet provided on the second end of the laser stripe region. The first cleaved semipolar facet is substantially parallel with the second cleaved semipolar facet. In a specific embodiment, the semipolar substrate is configured on a (30-31), (30-3-1), (20-21), (20-2-1), (30-32), (30-3-2) or offcut. The laser waveguide cavity is aligned in the projection of the c-direction. Mirror surfaces are formed on each of the cleaved surfaces. The first cleaved semipolar facet comprises a first mirror surface, typically provided by a scribing and breaking process. The scribing process can use any suitable technique, such as a diamond scribe or laser scribe or combinations. In a specific embodiment, the first mirror surface comprises a reflective coating. The reflective coating is selected from silicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia, aluminum oxide, including combinations, and the like. Depending upon the embodiment, the first mirror surface can be provided by an anti-reflective coating. Of course, there can be other variations, modifications, and alternatives. Also in a preferred semipolar embodiment, the second cleaved semipolar facet comprises a second mirror surface. The second mirror surface can be provided by a scribing and breaking process. Preferably, the scribing is performed by diamond or laser scribing. In a specific embodiment, the second mirror surface comprises a reflective coating, such as silicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia, aluminum oxide, combinations, and the like. In a specific embodiment, the second mirror surface comprises an anti-reflective coating. Of course, there can be other variations, modifications, and alternatives. In an alternative preferred semipolar embodiment, the device has a first cleaved m-face facet provided on the first end of the laser stripe region and a second cleaved m-face facet provided on the second end of the laser stripe region. The first cleaved m-facet is substantially parallel with the second cleaved m-facet. In a specific embodiment, the semipolar substrate is configured on (11-22) series of planes, enabling the formation of m-facets for laser cavities oriented in the m-direction. Mirror surfaces are formed on each of the cleaved surfaces. The first cleaved m-facet comprises a first mirror surface, typically provided by a scribing and breaking process. The scribing process can use any suitable technique, such as a diamond scribe or laser scribe or combinations. In a specific embodiment, the first mirror surface comprises a reflective coating. The reflective coating is selected from silicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia, aluminum oxide, including combinations, and the like. Depending upon the embodiment, the first mirror surface can be provided by an anti-reflective coating. Of course, there can be other variations, modifications, and alternatives. In an embodiment, the device includes a {30-31} crystalline surface region having gallium and nitrogen. A laser stripe region overlies a portion of the {30-31} crystalline surface region. The laser stripe region is characterized by a cavity orientation substantially parallel to a projection of the c-direction. The laser stripe region has a first end and a second end. The first end includes a first facet and the second end includes a second facet. The {30-31} crystalline surface region is off-cut less than +/−8 degrees towards a c-plane and/or an a-plane. In a preferred nonpolar embodiment, the device has a first cleaved c-face facet provided on the first end of the laser stripe region and a second cleaved c-face facet provided on the second end of the laser stripe region. In one or more embodiments, the first cleaved c-facet is substantially parallel with the second cleaved c-facet. In a specific embodiment, the nonpolar substrate is configured on (10-10) series of planes, which enables the formation of c-facets for laser cavities oriented in the c-direction. Mirror surfaces are formed on each of the cleaved surfaces. The first cleaved c-facet comprises a first mirror surface. In a preferred embodiment, the first mirror surface is provided by a scribing and breaking process. The scribing process can use any suitable techniques, such as a diamond scribe or laser scribe or combinations. In a specific embodiment, the first mirror surface comprises a reflective coating. The reflective coating is selected from silicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia, aluminum oxide including combinations, and the like. Depending upon the embodiment, the first mirror surface can also comprise an anti-reflective coating. Of course, there can be other variations, modifications, and alternatives. Also in a preferred nonpolar embodiment, the second cleaved c-facet comprises a second mirror surface. The second mirror surface can be provided by a scribing and breaking process, for example, diamond or laser scribing or the like. In a specific embodiment, the second mirror surface comprises a reflective coating, such as silicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia, aluminum oxide, combinations, and the like. In a specific embodiment, the second mirror surface comprises an anti-reflective coating. Of course, there can be other variations, modifications, and alternatives. In a specific embodiment, the laser stripe has a length and width. The length ranges from about 250 microns to about 3000 microns. The strip also has a width ranging from about 0.5 microns to about 50 microns, but can be other dimensions. In a specific embodiment, the width is substantially constant in dimension, although there may be slight variations. The width and length are often formed using a masking and etching process, such as commonly used in the art. In a specific semipolar embodiment, the device is also characterized by a spontaneously emitted light that is polarized in substantially parallel to the projection of the c-direction. That is, the device performs as a laser or the like. In a preferred embodiment, the spontaneously emitted light is characterized by a polarization ratio of greater than about 0.2 and less than about 1 parallel to the projection of the c-direction. In a preferred embodiment, the spontaneously emitted light is characterized by a wavelength ranging from about 500 to about 580 nanometers to yield a green laser. The spontaneously emitted light is highly polarized and is characterized by a polarization ratio parallel to the projection of the c-direction of greater than 0.4. Of course, there can be other variations, modifications, and alternatives. In a specific nonpolar embodiment, the device is also characterized by a spontaneously emitted light that is polarized parallel to the a-direction. That is, the device performs as a laser or the like. In a preferred embodiment, the spontaneously emitted light is characterized by a polarization ratio of greater than about 0.1 and less than about 1 parallel to the projection of the c-direction. In a preferred embodiment, the spontaneously emitted light characterized by a wavelength ranging from about 475 to about 540 nanometers to yield a blue-green or green laser and others and the spontaneously emitted light is highly polarized and is characterized by a polarization ratio parallel to the a-direction of greater than 0.5. Of course, there can be other variations, modifications, and alternatives. FIG.2is a detailed cross-sectional view of a laser device200fabricated on a non-polar substrate according to one embodiment of the present invention. As shown, the laser device includes gallium nitride substrate203, which has an underlying n-type metal back contact region201. The metal back contact region preferably is made of a suitable material such as those noted below. In a specific embodiment, the device also has an overlying n-type gallium nitride layer205, an active region207, and an overlying p-type gallium nitride layer structured as a laser stripe region209. In a specific embodiment, each of these regions is formed using an epitaxial deposition technique of metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial growth techniques suitable for GaN growth. In a specific embodiment, the epitaxial layer is a high quality epitaxial layer overlying the n-type gallium nitride layer. In some embodiments the high quality layer is doped, for example, with Si or O to form n-type material, with a dopant concentration between about 1016cm−3and 1020cm−3. In a specific embodiment, an n-type AluInvGa1-u-vN layer, where 0≤u, v, u+v≤1, is deposited on the substrate. In a specific embodiment, the carrier concentration may lie in the range between about 1016cm−3and 1020cm−3. The deposition may be performed using metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). As an example, the bulk GaN substrate is placed on a susceptor in an MOCVD reactor. After closing, evacuating, and back-filling the reactor (or using a load lock configuration) to atmospheric pressure, the susceptor is heated to a temperature between about 800 and about 1100 degrees Celsius in the presence of a nitrogen-containing gas. In one specific embodiment, the susceptor is heated to approximately 1000 degrees Celsius under flowing ammonia. A flow of a gallium-containing metalorganic precursor, such as trimethylgallium (TMG) or triethylgallium (TEG) is initiated, in a carrier gas, at a total rate between approximately 1 and 50 standard cubic centimeters per minute (sccm). The carrier gas may comprise hydrogen, helium, nitrogen, or argon. The ratio of the flow rate of the group V precursor (ammonia) to that of the group III precursor (trimethylgallium, triethylgallium, trimethylindium, trimethylaluminum) during growth is between about 2000 and about 12000. A flow of disilane in a carrier gas, with a total flow rate of between about 0.1 and 10 sccm, is initiated. In a specific embodiment, the laser stripe region is made of the p-type gallium nitride layer209. In a specific embodiment, the laser stripe is provided by an etching process selected from dry etching or wet etching. In a preferred embodiment, the etching process is dry, but other processes can be used. As an example, the dry etching process is an inductively coupled process using chlorine bearing species or a reactive ion etching process using similar chemistries. The chlorine bearing species are commonly derived from chlorine gas or the like. The device also has an overlying dielectric region, which exposes213contact region. In a specific embodiment, the dielectric region is an oxide such as silicon dioxide or silicon nitride. The contact region is coupled to an overlying metal layer215. The overlying metal layer is a multilayered structure containing gold and nickel (Ni/Au), gold and palladium (Pd/Au), gold and platinum (Pt/Au), but can be others. In a specific embodiment, the laser device has active region207. The active region can include one to twenty quantum well regions according to one or more embodiments. As an example following deposition of the n-type AluInvGa1-u-vN layer for a predetermined period of time, so as to achieve a predetermined thickness, an active layer is deposited. The active layer may comprise a single quantum well or a multiple quantum well, with 1-10 quantum wells. The quantum wells may comprise InGaN wells and GaN barrier layers. In other embodiments, the well layers and barrier layers comprise AlwInxGa1-w-xN and AlyInzGa1-y-zN, respectively, where 0≤w, x, y, z, w+x, y+z≤1, where w<u, y and/or x>v, z so that the bandgap of the well layer(s) is less than that of the barrier layer(s) and the n-type layer. The well layers and barrier layers may each have a thickness between about 1 nm and about 40 nm. In another embodiment, the active layer comprises a double heterostructure, with an InGaN or AlwInxGa1-w-xN layer about 10 nm to 100 nm thick surrounded by GaN or AlyInzGa1-y-zN layers, where w<u, y and/or x≥v, z. The composition and structure of the active layer are chosen to provide light emission at a preselected wavelength. The active layer may be left undoped (or unintentionally doped) or may be doped n-type or p-type. In a specific embodiment, the active region can also include an electron blocking region, and a separate confinement heterostructure. In some embodiments, an electron blocking layer is preferably deposited. The electron-blocking layer may comprise AlsIntGa1-s-tN, where 0≤s, t, s+t≤1, with a higher bandgap than the active layer, and may be doped p-type. In one specific embodiment, the electron blocking layer comprises AlGaN. In another embodiment, the electron blocking layer comprises an AlGaN/GaN super-lattice structure, comprising alternating layers of AlGaN and GaN, each with a thickness between about 0.2 nm and about 5 nm. As noted, the p-type gallium nitride structure, which can be a p-type doped AlqInrGa1-q-rN, where 0≤q, r, q+r≤1, layer is deposited above the active layer. The p-type layer may be doped with Mg, to a level between about 1016cm−3and 1022cm−3, and may have a thickness between about 5 nm and about 1000 nm. The outermost 1-50 nm of the p-type layer may be doped more heavily than the rest of the layer, so as to enable an improved electrical contact. In a specific embodiment, the laser stripe is provided by a dry etching process, but wet etching may also be used. The device also has an overlying dielectric region, which exposes contact region213. In a specific embodiment, the dielectric region is an oxide such as silicon dioxide. In a specific embodiment, the metal contact is made of suitable material. The reflective electrical contact may comprise at least one of silver, gold, aluminum, nickel, platinum, rhodium, palladium, chromium, or the like. The electrical contact may be deposited by thermal evaporation, electron beam evaporation, electroplating, sputtering, or another suitable technique. In a preferred embodiment, the electrical contact serves as a p-type electrode for the optical device. In another embodiment, the electrical contact serves as an n-type electrode for the optical device. Of course, there can be other variations, modifications, and alternatives. Further details of the cleaved facets appear below. FIG.3is a simplified diagram illustrating a laser structure according to a preferred embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims herein. One of ordinary skill in the art would recognize other variations, modifications, and alternatives. In a specific embodiment, the device includes a starting material such as a bulk nonpolar or semipolar GaN substrate, but can be others. In a specific embodiment, the device is configured to achieve emission wavelength ranges of 390 nm to 420 nm, 420 nm to 440 nm, 440 nm to 470 nm, 470 nm to 490 nm, 490 nm to 510 nm, 510 nm to 530 nm, and 530 nm to 550 nm, but can be others. In a preferred embodiment, the growth structure is configured using between 2 and 4 or 5 and 7 quantum wells positioned between n-type and p-type gallium and nitrogen containing cladding layers such as GaN, AlGaN, or InAlGaN. In a specific embodiment, the n-type cladding layer ranges in thickness from 500 nm to 5000 nm and has an n-type dopant such as Si with a doping level of between 1E18 cm−3and 3E18 cm−3. In a specific embodiment, the p-type cladding layer ranges in thickness from 300 nm to 1000 nm and has a p-type dopant such as Mg with a doping level of between 1E17 cm−3and 5E19 cm−3. In a specific embodiment, the Mg doping level is graded such that the concentration would be lower in the region closer to the quantum wells. In a specific preferred embodiment, the quantum wells have a thickness of between 2.0 nm and 4.0 nm or 4.0 nm and 7.0 nm, but can be others. In a specific embodiment, the quantum wells would be separated by barrier layers with thicknesses between 4 nm and 8 nm or 8 nm and 18 nm. The quantum wells and the barriers together comprise a multiple quantum well (MQW) region. In a preferred embodiment, the device has barrier layers formed from GaN or InGaN. In a specific embodiment using InGaN, the indium contents range from 1% to 5% (molar percent). An InGaN separate confinement heterostructure layer (SCH) could be positioned between the n-type cladding and the MQW region according to one or more embodiments. Typically, such separate confinement layer is commonly called the n-side SCH. The n-side SCH layer ranges in thickness from 10 nm to 50 nm or 50 nm to 150 nm and ranges in indium composition from 1% to 8% (mole percent), but can be others. In a specific embodiment, the n-side SCH layer may or may not be doped with an n-type dopant such as Si. In yet another preferred embodiment, an InGaN separate confinement heterostructure layer (SCH) is positioned between the p-type cladding layer and the MQW region, which is called the p-side SCH. In a specific embodiment, the p-side SCH layer ranges in thickness from 10 nm to 50 nm or 50 nm to 100 nm and ranges in indium composition from 1% to 7% (mole percent), but can be others. The p-side SCH layer may or may not be doped with a p-type dopant such as Mg. In another embodiment, the structure would contain both an n-side SCH and a p-side SCH. In a specific preferred embodiment, an AlGaN electron blocking layer, with an aluminum content of between 6% and 22% (mole percent), is positioned between the MQW and the p-type cladding layer either within the p-side SCH or between the p-side SCH and the p-type cladding. The AlGaN electron blocking layer ranges in thickness from 10 nm to 30 nm and is doped with a p-type dopant such as Mg from 1E18 cm−3and 1E20 cm−3according to a specific embodiment. Preferably, a p-contact layer positioned on top of and is formed overlying the p-type cladding layer. The p-contact layer would be comprised of a gallium and nitrogen containing layer such as GaN doped with a p-dopant such as Mg at a level ranging from 1E19 cm−3to 1E22 cm−3. Several more detailed embodiments, not intended to limit the scope of the claims, are described below. In a specific embodiment, the present invention provides a laser device capable of emitting 474 nm and also 485 nm, or 470 nm to 490 nm, or 510 nm to 535 nm wavelength light. The device is provided with one or more of the following elements, as also referenced inFIGS.4through6:an n-type cladding layer with a thickness from 1000 nm to 5000 nm with Si doping level of 1E17 cm−3to 3E18 cm−3;an n-side SCH layer comprised of InGaN with molar fraction of indium of between 1.5% and 6% and thickness from 35 to 125 nm;a multiple quantum well active region layers comprised of three to five 2.5-5.0 nm InGaN quantum wells separated by six 4.5-5.5 nm GaN barriers;a p-side SCH layer comprised of InGaN with molar fraction of indium of between 1.5% and 5% and thickness from 15 nm to 85 nm;an electron blocking layer comprised of AlGaN with molar fraction of aluminum of between 6% and 22% and thickness from 10 nm to 15 nm and doped with Mg;a p-type cladding layer with a thickness from 300 nm to 1000 nm with Mg doping level of 5E17 cm−3to 1E19 cm−3; anda p++—GaN contact layer with a thickness from 20 nm to 55 nm with Mg doping level of 1E20 cm−3to 1E21 cm−3. In a specific embodiment, the above laser device is fabricated on a nonpolar oriented surface region. Preferably, the 474 nm configured laser device uses a nonpolar (10-10) substrate with a miscut or off cut of −0.3 to 0.3 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the n-GaN/p-GaN is grown using an N2subflow and N2carrier gas. In yet an alternative specific embodiment, the present invention provides a laser device capable of emitting 486 nm wavelength light, among others, in a ridge laser embodiment. The device is provided with one or more of the following elements, as also referenced inFIGS.8through9:an n-GaN cladding layer with a thickness from 100 nm to 5000 nm with Si doping level of 5E17 cm−3to 3E18 cm−3;an n-side SCH layer comprised of InGaN with molar fraction of indium of between 3% and 5% and thickness from 40 to 60 nm;a multiple quantum well active region layers comprised of seven 4.5-5.5 nm InGaN quantum wells separated by eight 4.5-5.5 nm GaN barriers;a p-side guide layer comprised of GaN with a thickness from 40 nm to 50 nm;an electron blocking layer comprised of AlGaN with molar fraction of aluminum of between 15% and 22% and thickness from 10 nm to 15 nm and doped with Mg;a p-GaN cladding layer with a thickness from 400 nm to 1000 nm with Mg doping level of 5E17 cm−3to 1E19 cm−3; andp++—GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 2E19 cm−3to 1E21 cm−3. In a specific embodiment, the laser device is fabricated on a non-polar (10-10) oriented surface region (m-plane). In a preferred embodiment, the non-polar substrate has a miscut or off cut of −0.8 to −1.2 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the non-polar oriented surface region has an overlying n-GaN/p-GaN grown with H2/N2subflow and H2carrier gas. In a specific embodiment, the present invention provides an alternative device structure capable of emitting 481 nm light, among others, in a ridge laser embodiment. The device is provided with one or more of the following elements, as also referenced inFIGS.9through10;an n-GaN cladding layer with a thickness from 100 nm to 3000 nm with Si doping level of 5E17 cm−3to 3E18 cm−3;an n-side SCH layer comprised of InGaN with molar fraction of indium of between 3% and 6% and thickness from 45 to 80 nm;a multiple quantum well active region layers comprised of five 4.5-5.5 nm InGaN quantum wells separated by four 9.5 nm to 10.5 nm InGaN barriers with an indium molar fraction of between 1.5% and 3%;a p-side guide layer comprised of GaN with molar a thickness from 10 nm to 20 nm;an electron blocking layer comprised of AlGaN with molar fraction of aluminum of between 6% and 22% and thickness from 10 nm to 15 nm and doped with Mg.a p-GaN cladding layer with a thickness from 400 nm to 1000 nm with Mg doping level of 2E17 cm−3to 4E19 cm−3; anda p++—GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 5E19 cm−3to 1E21 cm−3. In a specific embodiment, the laser device is fabricated on a non-polar oriented surface region (m-plane). In a preferred embodiment, the non-polar substrate has a miscut or off cut of −0.8 to −1.2 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the non-polar oriented surface region has an overlying n-GaN/p-GaN grown with H2/N2subflow and H2carrier gas. In a specific embodiment, the present invention provides an alternative device structure capable of emitting 501 nm light in a ridge laser embodiment. The device is provided with one or more of the following elements, as also referenced inFIGS.11through13:an n-GaN cladding layer with a thickness from 100 nm to 3000 nm with Si doping level of 5E17 to 3E18 cm−3;an n-side SCH layer comprised of InGaN with molar fraction of indium of between 3% and 7% and thickness from 40 to 60 nm;a multiple quantum well active region layers comprised of seven 3.5-4.5 nm InGaN quantum wells separated by eight 9.5 nm to 10.5 nm GaN barriers;a p-side SCH layer comprised of InGaN with molar a fraction of indium of between 2% and 5% and a thickness from 15 nm to 25 nm;an electron blocking layer comprised of AlGaN with molar fraction of aluminum of between 8% and 22% and thickness from 10 nm to 15 nm and doped with Mg;a p-GaN cladding layer with a thickness from 400 nm to 1000 nm with Mg doping level of 5E17 cm−3to 1E19 cm−3; anda p++—GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 1E20 cm−3to 1E21 cm−3. In a specific embodiment, the laser device is fabricated on a non-polar (10-10) oriented surface region (m-plane). In a preferred embodiment, the non-polar substrate has a miscut or off cut of −0.8 to −1.2 degrees towards (0001) and −0.3 to 0.3 degrees towards (11-20). In a specific embodiment, the non-polar oriented surface region has an overlying n-GaN/p-GaN grown with H2/N2subflow and H2carrier gas. In a preferred embodiment, the laser device configured for a 500 nm laser uses well regions and barriers fabricated using slow growth rates of between 0.3 and 0.6 angstroms per second, but can be others. In a specific embodiment, the slow growth rate is believed to maintain the quality of the InGaN at longer wavelengths. In a specific embodiment, the present invention includes the following device structure. An optical device comprising:a gallium nitride substrate member having a semipolar crystalline surface region, the substrate member having a thickness of less than 500 microns, the gallium and nitride substrate member characterized by a dislocation density of less than 107 cm−2;a semipolar surface region having a root mean square surface roughness of 10 nm and less over a 5 micron by 5 micron analysis area;an offcut characterizing the surface region;a gallium and nitrogen containing n-type cladding layer overlying the surface region, the n-type cladding layer having a thickness from 300 nm to 6000 nm with an n-type doping level of 1E17 cm−3to 3E18 cm−3;an n-side separate confining heterostructure (SCH) waveguiding layer overlying the n-type cladding layer, the n-side SCH waveguide layer comprising at least gallium, indium, and nitrogen with a molar fraction of InN of between 1% and 8% and having a thickness from 20 nm to 150 nm;a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five 2.0 nm to 4.5 nm InGaN quantum wells separated by 3.5 nm to 20 nm gallium and nitrogen containing barrier layers;a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprising GaN or InGaN with a molar fraction of InN of between 1% and 8% and having a thickness from 10 nm to 120 nm;a p-type gallium and nitrogen containing cladding layer overlying the multiple quantum well active region, the p-type cladding layer having a thickness from 300 nm to 1000 nm with a p-type doping level of 1E17 cm−3to 5E19 cm−3;a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 120 nm with a p-type doping level of 1E19 cm−3to 1E22 cm−3;a waveguide member, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide region comprising a first end and a second end;a first facet formed on the first end; anda second facet formed on the second end. Depending upon the embodiment, the present device structure can be made according to the steps outlined below. In a specific embodiment, the present invention also includes the following device structure, and its variations in an optical device, and in particular a laser device. In this example, the optical device includes one more of the following elements:a gallium nitride substrate member having a semipolar crystalline surface region, the substrate member having a thickness of less than 500 microns, the gallium and nitride substrate member characterized by a dislocation density of less than 107cm−2;a semipolar surface region having an root mean square surface roughness of 10 nm and less over a 5 micron by 5 micron analysis area;an offcut characterizing the surface region;a surface reconstruction region configured overlying the semipolar surface region and the n-type cladding layer and at an interface within a vicinity of the semipolar surface region, the surface reconstruction region having an oxygen bearing concentration of greater than 1E17 cm−3;an n-type cladding layer comprising a first quaternary alloy, the first quaternary alloy comprising an aluminum bearing species, an indium bearing species, a gallium bearing species, and a nitrogen bearing species overlying the surface region, the n-type cladding layer having a thickness from 100 nm to 5000 nm with an n-type doping level of 1E17 cm−3to 6E18 cm−3;a first gallium and nitrogen containing epitaxial material comprising a first portion characterized by a first indium concentration, a second portion characterized by a second indium concentration, and a third portion characterized by a third indium concentration overlying the n-type cladding layer;an n-side separate confining heterostructure (SCH) waveguiding layer overlying the n-type cladding layer, the n-side SCH waveguide layer comprised of InGaN with molar fraction of InN of between 1% and 8% and having a thickness from 30 nm to 150 nm;a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five 2.0 nm to 4.5 nm InGaN quantum wells separated by 5 nm to 20 nm gallium and nitrogen containing barrier layers;a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprising GaN or InGaN with a molar fraction of InN of between 1% and 5% and having a thickness from 20 nm to 100 nm;a second gallium and nitrogen containing material overlying the p-side guide layer;a p-type cladding layer comprising a second quaternary alloy overlying the second gallium and nitrogen containing material, the p-type cladding layer having a thickness from 300 nm to 1000 nm with a magnesium doping level of 1E17 cm−3to 4E19 cm−3;a plurality of hydrogen species, the plurality of hydrogen species spatially disposed within the p-type cladding layer;a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 140 nm with a magnesium doping level of 1E19 cm−3to 1E22 cm−3; anda waveguide member, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide region comprising a first end and a second end;a first facet formed on the first end;a first semipolar characteristic configured on the first facet;a second facet formed on the second end;a second semipolar characteristic configured on the second facet;a first edge region formed on a first side of the waveguide member;a first etched surface formed on the first edge region;a second edge region formed on a second side of the waveguide member; anda second etched surface formed on the second edge region. In this example, the waveguide member is provided between the first facet and the second facet, e.g., semipolar facets having a scribe region and cleave region. In this example, the scribe region is less than thirty percent of the cleave region to help facilitate a clean break via a skip scribing techniques where the skip is within a vicinity of the ridge. The waveguide member has a length of greater than 300 microns and is configured to emit substantially polarized electromagnetic radiation such that a polarization is substantially orthogonal to the waveguide cavity direction and the polarized electromagnetic radiation having a wavelength of 500 nm and greater and a spontaneous emission spectral full width at half maximum of less than 50 nm in a light emitting diode mode of operation or a spectral line-width of a laser output of greater than 0.4 nm. The wavelength is preferably 520 nm and greater. The wall plug efficiency is 5 percent and greater. Depending upon the embodiment, the present device structure can be made according to the steps outlined below. In this example, the present method includes providing a gallium nitride substrate member having a semipolar crystalline surface region. The substrate member has a thickness of less than 500 microns, which has been thinned to less than 100 microns by way of a thinning process, e.g., grinding polishing. The gallium and nitride substrate member is characterized by a dislocation density of less than 107cm−2. The semipolar surface region is characterized by an off-set of +/−3 degrees from a (20-21) semipolar plane toward a c-plane. As an example, the gallium nitride substrate can be made using bulk growth techniques such as ammonothermal based growth or HVPE growth with extremely high quality seeds to reduce the dislocation density to below 1E5 cm−2, below 1E3 cm−2, or eventually even below 1El cm−2. In this example, the method also includes forming the surface reconstruction region overlying the semipolar surface region. The reconstruction region is formed by heating the substrate in the growth reactor to above 1000° C. with an ammonia (e.g., NH3) and hydrogen (e.g., H2) over pressure, e.g., atmospheric. The heating process flattens and removes micro-scratches and other imperfections on the substrate surface that lead to detrimental device performance. The micro-scratches and other imperfections are often caused by substrate preparation, including grinding, lapping, and polishing, among others. In this example, the present method also forms an n-type cladding layer by introducing gaseous species of at least ammonia with nitrogen or hydrogen and an n-type dopant bearing species. The n-type cladding layer comprises silicon as the n-type dopant. The method also includes forming of the first gallium and nitrogen containing epitaxial material comprises n-type GaN and underlies the n-type quaternary cladding. The cladding layer includes aluminum, indium, gallium, and nitrogen in a wurtzite-crystalline structure. Preferably, the quaternary cladding region facilitates substantial lattice matching to the primary lattice constant of the substrate to achieve an increased aluminum content and a lower index cladding region. The lower index cladding layer enables better confine optical confinement within the active region leading to improved efficiency and gain within the laser device. The cladding layer is made with sufficient thickness to facilitate optical confinement, among other features. The method includes forming the n-side separate confining heterostructure (SCH) waveguiding layer comprises processing at a deposition rate of less than 1.5 angstroms per second and an oxygen concentration of less than 8E17 cm−3. In this example, the n-side SCH is an InGaN material having a thickness and an oxygen concentration. The oxygen concentration is preferably below a predetermined level within a vicinity of the multiple quantum well regions to prevent any detrimental influences therein. Further details of the multiple quantum well region are provided below. In this example, the method includes forming the multiple quantum well active region by processing at a deposition rate of less than 1 angstroms per second and an oxygen concentration of less than 8E17 cm−3. The method also includes forming the p-side guide layer overlying the multiple quantum well active region by depositing an InGaN SCH layer with an InN molar fraction of between 1% and 5% and a thickness ranging from 10 nm to 100 nm. The method forms the second gallium and nitrogen-containing material overlying the p-side guide layer by a process comprising a p-type GaN guide layer with a thickness ranging from 50 nm to 300 nm. As an example, the quantum well region can include two to four well regions, among others. Each of the quantum well layers is substantially similar to each other for improved device performance, or may be different. In this example, the method includes forming an electron blocking layer overlying the p-side guide layer, the electron blocking layer comprising AlGaN with a molar fraction of AlN of between 6% and 22% and having a thickness from 5 nm to 25 nm and doped with a p-type dopant such as magnesium. The method includes forming the p-type cladding layer comprising a hydrogen species that has a concentration that tracks relatively with the p-type dopant concentration. The method includes forming a p++—gallium and nitrogen containing contact layer comprising a GaN material formed with a growth rate of less than 2.5 angstroms per second and characterized by a magnesium concentration of greater than 5E19 cm−3. Preferably, the electron-blocking layer redirects electrons from the active region back into the active region for radiative recombination. In this example, the present method includes an etching process for forming the waveguide member. The etching process includes using a dry etch technique such as inductively coupled plasma etching or reactive ion etching to etch to a depth that does not penetrate through the quantum well region to maintain the multiple quantum well active region substantially free from damage. In this example, the etching process may be timed or maintained to stop the etching before any damage occurs to the multiple quantum well region. The method includes forming the first facet on the first end and forming the second facet on the second end comprising a scribing and breaking process. In this example, the present method is generally performed in a MOCVD process. The MOCVD process preferably includes; (1) cleaning (via removal of quartz ware, vacuum, and other cleaning process); (2) subjecting the MOCVD chamber into a plurality of growth species; and (3) removing an impurity to a predetermined level. In this example, the impurity may be an oxygen bearing impurity, among others. In a specific example, the present method is performed using an atmospheric MOCVD tool configured to deposit epitaxial materials at atmospheric pressure, e.g., 700 Torr to 900 Torr. While the above has been a full description of the specific embodiments, various modifications, alternative constructions and equivalents can be used. Therefore, the above description and illustrations should not be taken as limiting the scope of the present invention which is defined by the appended claims. | 42,667 |
11862938 | DESCRIPTION OF THE EMBODIMENTS The embodiment of the present disclosure is described in detail below with reference to the drawings and element symbols, such that persons skilled in the art is able to implement the present application after understanding the specification of the present disclosure. The thickness ratio between the layers in the drawings is not the actual ratio, and the thickness of each layer should be adjusted according to actual needs. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and they are not intended to limit the scope of the present disclosure. In the present disclosure, for example, when a layer formed above or on another layer, it may include an exemplary embodiment in which the layer is in direct contact with the another layer, or it may include an exemplary embodiment in which other devices or epitaxial layers are formed between thereof, such that the layer is not in direct contact with the another layer. In addition, repeated reference numerals and/or notations may be used in different embodiments, these repetitions are only used to describe some embodiments simply and clearly, and do not represent a specific relationship between the different embodiments and/or structures discussed. Further, spatially relative terms, such as “underlying,” “below,” “lower,” “overlying,” “above,” “upper” and the like, may be used herein for ease of description to describe one device or feature's relationship to another device(s) or feature(s) as illustrated in the figures and/or drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures and/or drawings. Moreover, certain terminology has been used to describe embodiments of the present disclosure. For example, the terms “one embodiment,” “an embodiment,” and “some embodiments” mean that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, it is emphasized and should be appreciated that two or more references to “an embodiment” or “one embodiment” or “an alternative embodiment” in various portions of the present disclosure are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments of the present disclosure. Further, for the terms “including”, “having”, “with”, “wherein” or the foregoing transformations used herein, these terms are similar to the term “comprising” to include corresponding features. In addition, a “layer” may be a single layer or a plurality of layers; and “a portion” of an epitaxial layer may be one layer of the epitaxial layer or a plurality of adjacent layers. In the prior art, the laser diode can be optionally provided with a buffer layer according to actual needs, and in some embodiments, the materials of the buffer and the substrate may be the same. Whether the buffer is provided is not substantially related to the technical characteristics to be described in the following embodiments and the effects to be provided. Accordingly, for the sake of a brief explanation, the following embodiments are only described with a laser diode having a buffer layer, and no further description is given to a laser without a buffer layer; that is, the following embodiments can also be applied by replacing a laser diode without a buffer. A semiconductor laser diode mainly includes a substrate and a multi-layer structure. The multi-layer structure is formed on the substrate. It is well known that for semiconductor laser diode with different application purposes or working principles, the materials of the multi-layer structure and even the substrate will also be different. The phosphorus-containing semiconductor layer proposed in the present disclosure can reduce the defects or dislocations of the multi-layer structure or improve the carrier confinement ability of the laser diode, and even have both of the above effects in some cases. The semiconductor laser diode of the present disclosure refers to a suitable laser diode such as a VCSEL or an EEL, but excludes laser diodes whose lasing wavelength is less than 700 nm. Referring toFIG.1a, the semiconductor laser diode1′ of the present disclosure mainly includes a substrate10′ and a multi-layer structure100′. The multi-layer structure100′ is formed on the substrate10′. The multi-layer structure100′ includes an active region A′ and a phosphorus-containing semiconductor layer S1′. Referring toFIGS.1aand1b-1c, the phosphorus-containing semiconductor layer S1′ may be located at different positions in the active region A′. As shown inFIGS.1d-1e, the semiconductor layer S1′ may be located above or below the active region A′, and the semiconductor layer S1′ is directly in contact with the active region. As shown inFIGS.1f-1g, the semiconductor layer S1′ may be located above or below the active region A′, but the semiconductor layer S1′ is indirectly in contact with the active region A′; that is, there is also an epitaxial layer between the semiconductor layer S1′ and the active region A′. The specific embodiments are described as follows. Embodiment 1 Referring toFIGS.2-4b,FIG.2is a schematic diagram showing an existing VCSEL.FIG.3ais a schematic diagram showing an embodiment in which the active layer ofFIG.2is a quantum well structure.FIG.3bis a schematic diagram showing the energy bands level of the barrier layer and the well layer ofFIG.3a.FIG.4ais a schematic diagram showing a part of or the entire of barrier layer forms the first semiconductor layer.FIG.4bis a schematic diagram showing an embodiment in which each barrier layer forms a first semiconductor layer. The phosphorus-containing semiconductor layer S1′ ofFIGS.1a-1bis referred to as the first semiconductor S1in Embodiment 1.FIGS.2and3a-3bare related to the structure of the existing VCSEL, and the active layer is a quantum well structure. For specific embodiments of applying the first semiconductor layer to the VCSEL, please refer toFIGS.4a,4band related disclosure. The semiconductor laser diode shown inFIG.2is a VCSEL1. As shown inFIG.2, the VCSEL1includes a GaAs substrate10and a multi-layer structure100. The active region A of the multi-layer structure100includes an active layer20(the embodiments of multiple active layers are described later). The multi-layer structure100includes a buffer layer101, a lower DBR layer102, a lower spacer layer103, an active layer20, an upper spacer layer104, an upper DBR layer105and an ohmic contact layer106in order from bottom to top. The active layer20is provided between the lower spacer layer103and the upper spacer layer104. The materials of the epitaxial layers (such as the buffer layer101, the lower DBR layer102, the lower spacer layer103, the upper spacer layer104, the upper DBR layer105and the ohmic contact layer106) may be conventional semiconductor materials. According to actual needs, one or more epitaxial layers may be selectively disposed in the lower DBR layer102and/or the upper DBR layer105, such as an oxidation layer, an ohmic contact layer, a spacer layer or other appropriate epitaxial layers. As shown inFIG.3a, in the embodiment of the present disclosure, the active layer20may include two well layers201and three barrier layers203. These two well layers201and three barrier layers203are alternately stacked, but not limited thereto. That is, the active layer20may include n well layers201and n+1 barrier layers203. If the active layer20is configured in this manner, the uppermost layer and the lowermost layer of the active layer20are both barrier layers203. In some embodiments, the barrier layer203at the uppermost layer and the lowermost layer of the active layer20may serve as the lower spacer layer103or the upper spacer layer104. In an embodiment not shown, the active layer20may include n well layers201and n−1 barriers layer203. If the active layer20is configured in this manner, one of the uppermost layer and the lowermost layer of the active layer20is the well layer201, or both the uppermost layer and the lowermost layer of the active layer20are the well layer201. Preferably, n is an integer of 1 to 5 (that is, the active layer20includes at least one well layer), and more preferably, n is an integer of 2 to 5, thereby improving the optical gain or high temperature performance of the VCSEL. When the uppermost layer or the lowermost layer of the active layer20is the well layer201, the lower spacer layer103or the upper spacer layer104adjacent to the well layer201serves as a barrier layer. When both the uppermost layer and the lowermost layer of the active layer20are the well layers201, the lower spacer layer103and the upper spacer layer104adjacent to the well layers201both serve as barrier layers. In addition, as shown in the energy band diagram ofFIG.3b, the barrier layer203is a semiconductor material with a higher conduction band energy level (Ec), and the well layer201is a semiconductor material with a lower conduction band energy level such that a conduction band offset (ΔEc) occurs in a conduction band and the quantum well is formed. Similarly, a valence band offset (ΔEv) will also occur in a valence band. When the VCSEL1is forward biased, electrons and holes are injected and confined to the quantum well, and the injected electrons and holes recombine in the quantum well and emit light. In the most embodiments herein, the preferred material of the well layer201is InGaAs, InAlGaAs, GaAsSb, GaAs, AlGaAs, AlGaAsSb, GaAsP, InGaAsP or the combination of the above materials. The lasing wavelength of the VCSEL1can be adjusted by changing the composition or thickness of the well layer201such that the lasing wavelength of the semiconductor laser diode can easily reach 700 nm or more than 800 nm. However, some of the materials used as the well layer201are not lattice-matched to the GaAs substrate10. In particular, the lattice constants for the materials such as InGaAs, InAlGaAs, GaAsSb, AlGaAs and AlGaAsSb are greater than the lattice constant for the GaAs substrate. Therefore, the well layer will have compressive strain after the epitaxial growth of the well layer, and even if the composition of these materials is changed, the lattice constants therefor will still be greater than the lattice constant for the GaAs substrate. Moreover, the material with lattice constant less than that for the GaAs substrate is GaAsP. Thus, the well layer will have tensile strain after the epitaxial growth of the well layer. Similarly, even if GaAsP change its material composition, the lattice constant for GaAsP will be less than the lattice constant for the GaAs substrate. If some or each well layer in the active layer20has compressive strain or tensile strain, the strain will be accumulated in the active layer20or VCSEL. Once the accumulated strain in the VCSEL1is too large, the epitaxial layer of the VCSEL1may have defects or dislocations. As such, in the multi-layer structure, the first semiconductor layer S1containing phosphorus is provided. 17 preferred materials as the first semiconductor layer are shown in Table 1. Preferred materials for the first semiconductor layer S1include at least one of the 17 materials or a combination of at least two materials of the 17 materials in Table 1. TABLE 1firstAlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBisemiconductorAlGaInPAlGaInPNAlGaInPSbAlGaInPBilayerInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaPNInGaPSbInGaPBiInAlGaAsP The lattice constants for the materials listed above can be changed. For example, by adjusting the composition of the materials, it is determined that the lattice constants for the materials may be equal to, less than or greater than the lattice constant for the GaAs substrate. Therefore, the first semiconductor layer can be determined to induce tensile strain, compressive strain or even no obvious strain according to the strain of the well layer. In this way, the strain of the well layer can be effectively compensated by the first semiconductor layer such that the strain accumulated in the active layer becomes smaller, thereby reducing the probability of defect or dislocations occurrence of the epitaxial layer of the VCSEL and improving the reliability of the VCSEL. The total strain is calculated by multiplying the strain value of each layer by its thickness to obtain the product value and then subtracting the product value of all compressive strains from the product value of all tensile strains to obtain the total strain (absolute value). If only the strain of the active layer itself is considered, in principle, as long as the total strain of the active layer itself becomes small enough. In general, the total strain of the active layer becomes small, and the total strain of the VCSEL will also decrease. However, if the epitaxial layer outside the active layer provides considerable strain, the active layer induces appropriate strain and strain magnitude by appropriately selecting the material, material composition, layer number and thickness of the well layer and/or the first semiconductor layer such that the active layer can also moderately compensate the stain of the epitaxial layer outside the active layer. Taking InGaP in Table 1 as an example, assuming that the mole fraction In:Ga=0.51:0.49, InGaP is lattice-matched to the GaAs substrate. If the lattice constant for InGaP is greater than that for the GaAs substrate, the content of In must be increased (i.e., the content of Ga becomes smaller) such that the first semiconductor layer has compressive strain. If the lattice constant for InGaP is less than that for the GaAs substrate, the content of Ga must be increased (i.e., the content of In becomes smaller) such that the first semiconductor layer can have tensile strain. In principle, a part of or the entire of the barrier layer203is provided with the first semiconductor layer S1. For example,FIG.4ashows two ways to dispose the first semiconductor layer S1on the barrier layer. One is to form the first semiconductor layer S1in a part of the barrier layer203. As shown inFIG.4a, the barrier layer203is close to the upper spacer layer104. The other is to form the first semiconductor layer S1in the whole of the barrier layer203. As shown inFIG.4a, the barrier layer203is adjacent to the lower spacer layer103. The above-mentioned first semiconductor layer is partially formed or entirely formed in the barrier layer, and may be applied to one barrier layer or multiple barrier layers. For example, parts of some barrier layers form first semiconductor layers, and other entire barrier layers form first semiconductor layers. As shown inFIG.4b, each barrier layer is provided with a first semiconductor. It should be noted that the number, arrangement and position of the first semiconductor layer depend on the generation position and magnitude of strain of the well layer, but not limited thereto described in this embodiment. In this embodiment, by inserting the phosphorus-containing first semiconductor layer S1into the barrier layer203, the barrier layer203may perform strain compensation on the well layer201. For example, when the compressive strain is induced in the well layer201, the first semiconductor layer S1in the barrier layer203has tensile strain such that the total strain accumulated in the active layer20becomes smaller. In addition, the barrier layer203with the first semiconductor layer S1may further increase the energy band gap difference between the barrier layer with first semiconductor layer S land the well layer, thereby increasing carrier confinement of the active layer. When operating at high temperatures, carriers with higher energy can be confined in quantum wells such that the optical performance of the VCSEL becomes better when operating at high temperature. It should be noted that the compressive strain or tensile strain induced by the well layer is determined by material of the well layer, the material composition of the well layer or the material of the substrate. If the well layer has tensile strain, the first semiconductor layer should have compressive strain. Similarly, if the well layer has compressive strain, the first semiconductor layer should have tensile strain. If the bandgap of the first semiconductor layer is larger, the carrier confinement capability of the VCSEL can also be improved. In some embodiments, the thickness of a well layer may preferably be 1 nm to 30 nm, more preferably 2 nm to 15 nm, and still preferably 3 nm to 10 nm, wherein the thickness of a well layer can be adjusted in accordance with the material, material composition or desired wavelength of the well layer. As described above, the barrier layer203may not only perform strain compensation on the well layer201, but also the strain to which the barrier layer203performs strain compensation on the well layer201can be adjusted. Specifically, when the material, material composition or thickness of the barrier layer203is/are changed, the strain to which the barrier layer203performs strain compensation on the well layer201can be adjusted. The thickness of a barrier layer203may be 1 nm to 30 nm, preferably 2 nm to 15 nm, and still preferably 3 nm to 10 nm so as to reduce or eliminate the strain of the active layer20. Embodiment 2 FIG.5ais a schematic diagram showing an embodiment with an intermediate layer between the barrier layer and the well layer.FIG.5bis a schematic diagram showing the energy band relationship between the barrier layer, the intermediate layer and the well layer ofFIG.5a.FIG.6ais a schematic diagram showing an embodiment of an intermediate layer of GaAsP inserted in the barrier layer.FIG.6bis a schematic diagram showing the energy band relationship between the barrier layer, the intermediate layer and the well layer ofFIG.6a.FIG.7ais a schematic diagram showing an embodiment of an intermediate layer of AlGaAsP inserted in the barrier layer.FIG.7bis a schematic diagram showing the energy band relationship between the barrier layer, the intermediate layer and the well layer ofFIG.7a. Compared withFIG.3a, as shown inFIG.5a, an intermediate layer205is inserted between the well layer201and the barrier layer203, and the barrier layer203does not directly contact the well layer201. Alternatively, as shown inFIG.6a, an intermediate layer205is provided in the barrier layer203of the active layer20; in other words, a layered structure of the barrier layer203, the intermediate layer205and the barrier layer203is sequentially formed. Referring to Table 2, there are a total of 20 preferred materials for the intermediate layer205, and the materials used as the intermediate layer are at least one of the materials or a suitable combination of two or more materials listed in Table 2. Preferably, Embodiment 2 may be used in combination with Embodiment 1; that is, the intermediate layer includes at least one material of Table 2, and the barrier layer includes at least one material of Table 1. TABLE 2intermediateGaAsAlGaAsInAlGaAsPGaAsPlayerAlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBiInAlGaPInAlGaPNInAlGaPSbInAlGaPBiInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaP NInGaPSbInGaPBi The lattice constants for the materials listed in Table 2 can be changed to be less than, greater than or equal to the lattice constant for the GaAs substrate. Accordingly, the intermediate layer can be determined to have tensile strain, compressive strain or even no strain. In some embodiments, the materials of the barrier layer203and the intermediate layer205may be the same or different, and the materials of the barrier layer203and the intermediate layer205are preferably different. Even if the materials of the barrier layer203and the intermediate layer205are the same, the composition of the two materials is different. For example, when the materials of the barrier layer203and the intermediate layer205are AlGaAsP, the composition of aluminum, gallium, arsenic or phosphorus is different. AlthoughFIG.5ashows an embodiment in which the uppermost layer and the lowermost layer of the active layer20are the barrier layers203, the uppermost layer and/or the lowermost layer of the active layer20may be the well layer201. When the uppermost layer or the lowermost layer of the active layer20is the well layer201, the well layer201may substantially contact the lower spacer103or the upper spacer layer104; when both the uppermost layer and the lowermost layer of the active layer20are well layers201, the well layer201may substantially contact the lower spacer layer103and the upper spacer layer104. In an embodiment, as shown inFIG.5b, when the intermediate layer205is GaAsP, the conduction band energy level of the intermediate layer205is between that of the well layer201and the barrier layer203. Since the intermediate layer does not contain aluminum, and is not easily oxidized, the strain of the well layer can be compensated by the intermediate layer. For example, when the well layer has compressive strain, the intermediate layer has tensile strain to reduce the total strain in the active layer. In some embodiments, as shown inFIGS.6aand7a, when the materials of the intermediate layer205are GaAsP and AlGaAsP, respectively, the energy band diagrams corresponding toFIGS.6aand7aare shown inFIGS.6band7b, respectively. The intermediate layer205is not limited to a material that provides tensile strain, and may have a material that provides compressive strain or no obvious strain according to the energy band offset of the quantum well and strain compensation. The thickness of an intermediate layer205may be 1 nm to 30 nm, preferably 2 nm to 15 nm, and still preferably 3 nm to 10 nm, and the total thickness of the intermediate layer205and the barrier layer203is between two adjacent well layers201is between 1 nm and 30 nm, preferably between 2 nm and 15 nm, and still preferably between 3 nm and 10 nm. In general, the total strain of the well layer, the barrier layer and the intermediate layer of the active layer should be lower than the total uncompensated strain. Accordingly, the intermediate layer may be determined according to the types and magnitudes of the strain of the well layer and the barrier layer to induce compressive strain, tensile strain or no strain. The total strain can be changed in accordance with the materials, the material composition, layer quantity or thickness of the barrier layer, the intermediate layer, the well layer, but not limited thereto. Although Embodiment 2 is an intermediate layer provided in an active layer. Similarly, in the embodiment of multiple active layers (multi-junction), Embodiment 2 may also be used in one of multiple active layers, some active layers or each active layer of the laser diode. Embodiment 3 Referring toFIG.8a,FIG.8ais a schematic diagram showing an embodiment in which a second semiconductor layer is used as a barrier layer, and an intermediate layer is disposed between the second semiconductor layer and the well layer. Referring toFIG.8b,FIG.8bshows a schematic diagram of an embodiment in which the semiconductor a second semiconductor layer is used as a barrier layer, and an intermediate is inserted into the barrier layer. In Embodiment 3, a VCSEL is taken as an example. The structure of Embodiment 3 is similar to that of Embodiments 1 and 2 in the multi-layer structure100and the quantum well structure of the active layer20. In terms of materials, the second semiconductor layer S2and the intermediate layer205of Embodiment 3 are different from the first semiconductor S1and the intermediate layer of Embodiment 1. Specifically, the phosphorus-containing material of the second semiconductor layer S2is limited to GaAsP, the second semiconductor layer S2is at least a part of or the entire of the barrier layer203, and the material of the intermediate layer205is at least one or a combination of two or more materials of the 19 materials listed in Table 3. The materials of the well layer201are the same as the preferred materials of Embodiment 1. The preferred materials for the well layer are InGaAs, InAlGaAs, GaAsSb, GaAs, AlGaAs, AlGaAsSb, GaAsP, InGaAsP or a combination of the above materials. TABLE 3intermediateGaAsAlGaAsInAlGaAsPlayerAlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBiInAlGaPInAlGaPNInAlGaPSbInAlGaPBiInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaPNInGaPSbInGaPBi Among the materials listed in Table 3, except that AlGaAs has compressive strain and GaAs does not have strain, the lattice constants of the rest of the materials can be changed to be less than, greater than or even equal to the lattice constant of the GaAs substrate. Therefore, the intermediate layer can be determined to have tensile strain, compressive strain or even no strain. In some embodiments, when the material of the well layer201is InGaAs or InAlGaAs, the optical gain or frequency response of the VCSEL can be further improved. By inserting a GaAsP layer (i.e., the second semiconductor layer) in the barrier layer203and the substrate is a GaAs substrate, the GaAsP layer with a lattice constant less than that of the GaAs substrate can induces tensile strain, and strain compensation is performed on the well layer, thereby reducing or eliminating the total strain in the active layer20. This can improve the reliability of semiconductor laser diode. In an embodiment, when the conduction band energy level of the intermediate layer205is higher than the conductive band energy level of the barrier layer203made of GaAsP, the energy band offset between the intermediate layer205and the well layer201will be greater than the energy band offset between the GaAsP barrier layer203and the well layer201. This can improve the carrier confinement ability of quantum wells, the high-temperature performance or reliability of the semiconductor laser diode. Although Embodiment 3 takes the well layer, the barrier layer and the intermediate layer in an active layer as an example. Similarly, in the embodiment of multi-active layer (multi-junction), Embodiment 3 can also be used in an active layer, some active layers or each active layer in the multi-active layer of the laser diode. Embodiment 4 The materials of the well layer and the intermediate layer and the barrier layer are InGaAs, AlGaAs and GaAsP, respectively. The AlGaAs intermediate layer is provided in the GaAsP barrier layer. GaAsP can provide tensile strain, reduce the total strain of the active layer and the semiconductor laser diode, and reduce the dislocation or defects of the epitaxial layer in the semiconductor laser diode. AlGaAs can increase the energy band offset to the well layer, thereby enhancing the carrier confinement ability of quantum wells to improve the high-temperature performance of the semiconductor laser diode. Embodiment 5 The materials of the well layer and the barrier layer are InGaAs and AlGaAsP, respectively (no intermediate layer provided). The AlGaAsP barrier layer can provide tensile strain, reduce the total strain of the active layer or the semiconductor laser diode, and reduce the defects or dislocation of the epitaxial layer in the semiconductor laser diode. The AlGaAsP barrier layer can increase the energy band offset to the InGaAs well layer, thereby improving the carrier confinement ability of quantum wells to improve the high-temperature performance of the semiconductor laser diode. Alternatively, when it is no longer necessary to increase the energy band offset to the quantum well, the aluminum content of the AlGaAsP barrier layer can be appropriately lowered, and the probability of the active layer of the semiconductor laser diode being oxidized also becomes lower, thereby improving the reliability of the semiconductor laser diode. Embodiment 6 Referring toFIG.9,FIG.9is a schematic diagram illustrating an embodiment of a VCSEL having an active region with multiple active layers (multi-junction VCSEL). As shown inFIG.9, the active region A includes active layers20and21. At least one of the embodiments of the first semiconductor layer S1of Embodiment 1, the intermediate layer of Embodiment 2 and the second semiconductor layer S2of Embodiment 3 can be applied to the active layers20and/or21. Please refer to the foregoing for the related disclosure. It should be noted that in the embodiment of the multi-active layer (multi-junction), as shown in in Table 4, the material of the first semiconductor layer includes GaAsP in addition to the 17 materials listed in Table 1. TABLE 4firstAlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBisemiconductorInAlGaPInAlGaPNInAlGaPSbInAlGaPBilayerInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaPNInGaPSbInGaPBiInAlGaAsPGaAsP The number of multiple active layers is not limited to two layers, but may also be three layers, four layers or more than five layers, in which there is an epitaxial region between two adjacent active layers or any two adjacent active layers. In some embodiments, the tunnel junction25is at least provided in the epitaxial region. The multiple active layers help to improve the optical output power and power conversion efficiency, but the greater the number of active layers, the easier the strain is to accumulate. By appropriately determining the materials, material composition, layer quantity or thickness of the well layer, the first semiconductor layer S1or the second semiconductor layer S2, the total strain of the active layers or VCSEL can be reduced. AlthoughFIG.9also shows that the oxidation layer24and the spacer layers261-263are further provided in the epitaxial region, the oxidation layer24or the spacer layers261-263are selectively configured according to actual needs. For example, the spacer layers261-263are usually used to adjust the optical phase or as an optical confinement layer or as a carrier confinement layer.FIG.9shows a preferred embodiment of the oxidation layer24and the spacer layers261-263. The spacer layers261,262and263may be inserted between the active layer20and the oxidation layer24, between the oxidation layer24and the tunnel junction25and between the tunnel junction25and the active layer21. In the case of three or more active layers, an oxidation layer and/or a spacer layer may be selectively or further formed between any two adjacent active layers. The specific implementation of the oxidation layer and/or the spacer layer can be changed according to actual needs, in addition to the foregoing. In some embodiments, the first semiconductor layer is provided in the spacer layers261,263adjacent to the active layer20and/or the active layer21; or the first semiconductor layer is provided in the active layer. The specific implementation of the first semiconductor layer is as described in Embodiment 1, 2 or 3. In the prior art, common materials for the barrier layer are AlGaAs, GaAsP and GaAs. Compared with GaAsP or GaAs, the carrier confinement can be improved due to the large energy band offset between AlGaAs and the well layer. Therefore, when operating at high temperature, AlGaAs barrier is able to confine the carriers better in the quantum well such that the optical performance of VCSEL becomes better. However, when the material of the barrier layer is AlGaAs, the barrier layer will have compressive strain. If the well layer also has compressive strain, excessive compressive strain will be accumulated in the active layer, and will cause the epitaxial layer of the VCSEL to be prone to defects or dislocations, thus resulting in poor reliability of the VCSEL. When there are too many defects or dislocations, the optical performance of the VCSEL will deteriorate. Although increasing the aluminum content in the barrier layer may increase the energy band offset to improve carrier confinement of the quantum well, however, as the aluminum content increase, the probability of the active layer being oxidized tends to increase. Since the oxidation of aluminum in the active layer causes defects in the active layer, the optical performance or reliability of the VCSEL will be deteriorated. When the material of the barrier layer is AlGaAsP (the material listed in Table 1), and compared to the material of the barrier layer being AlGaAs, when the aluminum compositions of the AlGaAsP barrier layer and the AlGaAs barrier layer are exactly the same and the materials of the well layers are also exactly the same, the energy band offset between the AlGaAsP barrier layer and the well layer will be larger than the energy band offset between the AlGaAs barrier layer and the well layer, the carrier confinement will also be increased. When the material of the barrier layer is AlGaAs, the energy band offset to the well layer can only be increased by increasing the aluminum composition of AlGaAs, but the higher the aluminum composition, the easier the barrier layer is to be oxidized. After the first semiconductor layer S1containing phosphorus is provided in the barrier layer, the oxidation rate of the barrier layer containing phosphorus will be slower than that of the barrier layer not containing phosphorus when the aluminum composition (content) is the same. In addition, in the case of the same aluminum content, the energy band offset between AlGaAsP barrier layer and the well layer is greater than that between AlGaAs barrier layer and the well layer. Therefore, the aluminum content of AlGaAsP does not need to be as much as that of AlGaAs for the same energy band offset. Additionally, AlGaAsP increases the energy band offset to the well layer by increasing the phosphorus content such that the aluminum content can be further reduced. Accordingly, the probability of the active layer of the VCSEL1being oxidized is lowered, the occurrence of defects of the active layer or the VCSEL can be further lowered so as to improve the reliability of the VCSEL. The amount of phosphorus and aluminum can be adjusted according to the energy band offset of the quantum well and the strain compensation. Similarly, when the first semiconductor layer formed in the barrier layer203uses any of the other phosphorus-containing materials listed in Table 1, it also has the effect of increasing the reliability of the VCSEL. Embodiment 7 FIG.10ais a schematic diagram showing an embodiment in which a first semiconductor layer is formed above and below an active layer.FIG.10bshows a schematic diagram of an embodiment in which the first semiconductor is formed between the active layer and the lower spacer layer. FIGS.10aand10bshow a VCSEL as an example. As shown inFIG.10a, the first semiconductor S1is provided above and below the active region. The material of the first semiconductor layer above and/or below the active region is at least one of the materials or a combination of at least two materials listed in Table 5. The20materials listed in Table 5 include the17materials in Table 1 and GaAsP, AlGaAs and GaAs. TABLE 5AlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBiAlGaInPAlGaInPNAlGaInPSbAlGaInPBiInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaPNInGaPSbInGaPBiInAlGaAsPGaAsPAlGaAsGaAs In some embodiments, as shown inFIG.10a, the entire upper spacer layer104is the first semiconductor layer S1, and one surface of the first semiconductor layer S1is substantially in contact with the active layer20. Alternatively, a part of the lower spacer layer103is provided with the first semiconductor layer S1, and the first semiconductor layer S1may not be substantially in contact with the active layer20, that is, a part of the lower spacer layer103is between the first semiconductor layer S1and the active layer20. Whether the lower spacer layer103or the upper spacer layer104directly or indirectly contacts the active layer20depends on implementation needs. When the first semiconductor layer S1is in the lower spacer layer103or the upper spacer layer104, whether the first semiconductor layer S1directly or indirectly contacts the active layer20depends on implementation needs. In some embodiments, the materials of the “upper spacer layer and first semiconductor layer” or the “lower spacer layer and first semiconductor layer” may be the same or different. Even if the materials of the “upper spacer layer and first semiconductor layer” or the “lower spacer layer and first semiconductor layer” are the same, the composition of these two materials may be different. In some embodiments, as shown inFIG.10b, the first semiconductor layer S1is formed between the lower spacer layer103and the active layer20, but not limited thereto. The first semiconductor layer S2may also be formed between the upper spacer layer104and the active layer20(not shown). In the case that the first semiconductor layer S1is in indirect contact with the active layer, in principle, the closer the first semiconductor S1is to the active layer20, the more obvious the effect of the carrier confinement capability or strain compensation of the active layer20is improved. However, it is not limited that the first semiconductor layer S1must be in contact with or adjacent to the active layer. If the upper or lower spacer layer is thin enough or the first semiconductor layer provides sufficient strain, even if there is an epitaxial layer between the first semiconductor layer and the active layer, a certain carrier confinement capability to the active layer or reduce the total strain of the active layer or the VCSEL can still be provided by the first semiconductor layer. It is worth noting that when the first semiconductor layer S1is disposed outside the active layer20, the barrier layer or the intermediate layer of the active layer may use conventional materials, or another first semiconductor layer is provided in the active layer. Please refer to the first semiconductor layers of Embodiments 1-3 with respect to the specific implementation of another first semiconductor layer. When the well layer or the epitaxial layer of the laser diode has considerable strain, by applying any of the above-mentioned embodiments or a combination of some embodiments to the laser diode, the strain of the active layer or the laser diode is controlled within a certain range. In the above embodiments, for example, some materials in Table 1 will have obvious carrier confinement effects under appropriate conditions. Although some contents about the carrier confinement are mentioned in the foregoing, they are scattered in different places in the foregoing. Therefore, some preferred embodiment with respect to the carrier confinement will be described in detail as follows. Embodiment 8 FIG.11ashows a schematic diagram of an embodiment of the carrier confinement layer in the active region,FIG.11bis a schematic diagram showing another embodiment of the carrier confinement layer in the active region,FIG.11cshows a schematic diagram of an embodiment of the carrier confinement layer outside the active layer, andFIG.11dis a schematic diagram showing another embodiment of the carrier confinement layer outside the active region. FIGS.11a-11dare substantially the same asFIGS.1b-1e, in which the phosphorus-containing semiconductor layer S1′ is uniformly referred to as the carrier confinement layer CF′ in Embodiment 8, and the active layer A′ shown inFIGS.11a-11dincludes one active layer. With regard to the embodiments of the multi-active layer, please refer to the following Embodiments 12-15. As shown inFIGS.11a-11d, the multilayer structure includes an active region A′, a lower epitaxial region30′ and an upper epitaxial region40′. The lower epitaxial region30′ and the upper epitaxial region40′ are disposed below and above the active region A′. The surface of the active region A′ facing the lower epitaxial region30′ is defined as the first surface J1, and the surface of the active region A′ facing the upper epitaxial region40′ is defined as the second surface J2. In the following, if it is called “the surface of the active layer” alone, it represents the first surface and/or the second surface. In the embodiments of the multi-active layer, it will also include the third surface, the fourth surface and the Nth surface as well as “the surface of the active layer” represents one, two or more of the first to Nth surfaces. When the carrier confinement layer CF′ is disposed in the active region A′, in this configuration, whether the carrier confinement layer CF′ is substantially in contact with or close to the lower epitaxial region30′ or the upper epitaxial region40′ and the carrier confinement layer CF′ will have carrier confinement effects. In some embodiments, the carrier confinement layer CF′ may even disposed in one barrier layer or barrier layers of the active layer. When the carrier confinement layer CF′ is disposed in the lower epitaxial region30′ or the upper epitaxial region40′, in this configuration, in principle, the closer the carrier confinement layer CF′ is to the active region A′, the more obvious the carrier confinement effect is improved. In some embodiments, one surface of the carrier confinement layer can be seen as the first surface J1or the second surface J2; that is, the carrier confinement layer is formed as the uppermost part of the lower epitaxial region or as the lowermost part of the upper epitaxial region, or the carrier confinement layer constitutes the lowermost or uppermost part of the active region. In other words, the carrier confinement layer is disposed between the lower epitaxial region and the active region or between the active region and the upper epitaxial region. In some embodiments, there is also a part of an epitaxial layer, an epitaxial layer or some epitaxial layers between the carrier confinement layer and the first surface J1or between the carrier confinement layer and the second surface J2. Preferably, the material of the carrier confinement layer CF′ is at least one material or a combination of more than two materials listed in Table 6. TABLE 6carrierAlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBiconfinementAlGaInPAlGaInPNAlGaInPSbAlGaInPBilayerInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaPNInGaPSbInGaPBiInAlGaAsP Embodiment 9 FIGS.11a-11dare schematic diagrams of embodiments in principle, and please refer toFIGS.12a-12cwith respect to the embodiments specifically applied to VCSELs.FIG.12ais a schematic diagram showing an embodiment in which a carrier confinement layer is provided in a part of a lower spacer layer,FIG.12bshows a schematic diagram of an embodiment in which a carrier confinement layer is provided in the entire upper spacer layer, andFIG.12cis a schematic diagram showing that each barrier layer of the active layer is provided with a carrier confinement layer. Referring toFIG.12aand in conjunction withFIG.11d, the lower spacer layer103ofFIG.12acan be regarded as in the lower epitaxial region30′ ofFIG.11d. As shown inFIG.12a, the carrier confinement layer CF is formed in a part of the lower spacer layer103. The carrier confinement layer CF has an effective distance in which the carrier can be confined to the active layer from the first surface J1, such that the carrier confinement layer CF does not need to contact with the active layer In some embodiments, the entire upper spacer layer104forms a carrier confinement layer CF, as shown inFIG.12b. AlthoughFIG.12cshows that the carrier confinement layer CF is disposed in a part of each barrier layer203, but not limited thereto, the carrier confinement layer CF may be disposed in some entire barrier layers or all the entire barrier layers. In summary, in Embodiment 9, the carrier confinement layer is formed near one surface of the active layer. When the material of the carrier confinement layer is at least one of the materials listed in Table 6, the conduction band offset or the valence band offset between the carrier confinement layer and the well layer becomes larger. As such, when holes or electrons are injected into the active layer, especially at a high temperature operation, electrons or holes in the active layer will be confined by the carrier confinement layer, and the better the carrier confinement capability is, the better the VCSEL's optical performance is. Embodiment 10 In Embodiment 10, a carrier confinement layer CF is formed near one surface of the active layer. The material of the carrier confinement layer CF may be selected from at least one of the materials or a combination of at least two materials listed in Table 7 or Table 8. The materials in Table 7 have a larger barrier height to holes such that the effect on the confinement of holes is better. The materials in Table 8 have a larger barrier height to electrons such that the effect on the confinement of electrons is better. TABLE 7AlGaInPAlGaInPNAlGaInPSbAlGaInPBiInGaAsPInGaAsPNInGaAsPSbInGaAsPBiInGaPInGaPNInGaPSbInGaPBiInAlGaAsP TABLE 8AlGaAsPAlGaAsPNAlGaAsPSbAlGaAsPBiAlGaInPAlGaInPNAlGaInPSbAlGaInPBiInAlGaAsP TakingFIG.12aas an example, in the case that holes are injected into the active layer20through the upper DBR layer105and the second surface J2, when the material of the carrier confinement layer CF adjacent to the first surface J1is any of the materials in Table 7, the carrier confinement layer CF has a large barrier height to holes. Therefore, when holes continue to move toward the GaAs substrate, holes will be confined by the carrier confinement layer CF, thereby improving the carrier holes confinement of the active layer. It is worth mentioning that, in the above case, when the material of the carrier confinement layer adjacent to the first surface J1is InGaP or AlGaInP of Table 7, and the material of the epitaxial layer adjacent to the carrier confinement layer is AlGaAs or other suitable materials, the electron barrier height at the interface between InGaP and AlGaAs or between AlGaInP and AlGaAs is relatively small, or no electron barrier height therebetween. Therefore, electrons can be injected into the active layer without hindrance such that the resistance in the laser diode does not easily increase. In this case, the upper DBR layer105is mainly a P type, and the lower DBR layer102is mainly an N type. Also takingFIG.12aas an example, in the case that electrons are injected into the active layer20via the upper DBR layer105and the second surface J2, when the material of the carrier confinement layer CF adjacent to the first surface J1is any of the materials in Table 8, the carrier confinement CF has a larger barrier to electrons. Accordingly, when electrons continue to move toward the GaAs substrate, electrons will be confined by the carrier confinement layer CF, thereby enhancing the electron confinement of the active layer. It is worth mentioning that, in the above case, when the material of the carrier confinement layer adjacent to the first surface J1is AlGaAsP of Table 8, and the material of the epitaxial layer adjacent to the carrier confinement layer is AlGaAs or other suitable materials, the hole barrier height at the surface between AlGaAsP and AlGaAs is relatively small. Therefore, holes can be injected into the active layer without hindrance such that the resistance in the laser diode does not easily increase. In this case, the upper DBR layer105is mainly a N type, and the lower DBR layer102is mainly an P type. Embodiment 11 As shown inFIG.13, Embodiment 11 includes two carrier confinement layers CF1and CF2. These two carrier confinement layers CF1and CF2are formed near the first surface J1and the second surface J2of the active layer20, respectively. In the case that holes and electrons are injected into the active layer from the second surface J2and the first surface J1, respectively, when the materials of the carrier confinement layer CF1and the carrier confinement layer CF2are selected from at least one of the materials in Table 7 and Table 8, both the barriers height of the carrier confinement layer CF1to holes and the carrier confinement layer CF2to electrons can be increased such that the confinements of the holes and electrons are enhanced, and the performance of the laser diode can be improved. Similarly, in the case that holes and electrons are injected into the active layer from the first surface J1and the second surface J2, respectively, when the materials of the carrier confinement layer CF1and the carrier confinement CF2are selected from at least one of the materials in Table 8 and Table 7, both the barriers height of the carrier confinement CF1to electrons and the carrier confinement layer CF2to holes can be increased such that the confinements of the holes and electrons are enhanced, and the performance of the laser diode can be improved. In a preferred embodiment, when InGaP or AlGaInP is selected from Table 7, AlGaAsP is selected from Table 8, and the material of epitaxial layer adjacent to the carrier confinement layers CF1and CF2is AlGaAs or other suitable materials, not only the confinements of holes and electrons have been significantly enhanced, but also the holes and electrons can be injected into the active layer without hindrance. When at least one of the materials listed in Table 6, Table 7 or Table 8 is selected as the material of the carrier confinement layer, and the carrier confinement layer is disposed in an appropriate position, the carrier confinement effect can be enhanced, especially under the high temperature operation. In this case, the barrier layer in the active layer can use a material that does not induce strain, or the first semiconductor layer can be disposed above, below or in the active layer to induce appropriate strain for stain compensation. Please refer to the related embodiments of the first semiconductor layer for specific implementation. Embodiment 12 FIGS.14a-14care simplified schematic diagrams showing some representative embodiments in which the active region includes two active layers, and the confinement layer is disposed between these two active layer. As shown inFIG.14a, the active regions A′ includes two active layers20′ and21′. When the carrier confinement layer CF′ is disposed in the active region A′, the carrier confinement layer CF′ may be disposed between the second surface J2and the third surface J3. The carrier confinement layer CF′ may be separated from the second surface J2or the third surface J3by an effective distance that can confine the carriers to the active layer. In the case of multiple active layers with more than three active layers, one or two carrier confinement layers may be disposed between two adjacent active layers, or one or two carrier confinement layers may be disposed between any two adjacent active layers. In other embodiments, as shown inFIGS.14band14c, the carrier confinement layer CF′ may directly contact the second surface J2or the third surface J3. It must be explained again thatFIGS.14a,14band14cshow that the carrier confinement layer CF′ is between two active layers20′ and21′, but not limited thereto. In an alternative embodiment, the carrier confinement layer CF′ may be disposed in the active layer. In the case ofFIG.14a, the carrier confinement layer CF′ is close to the second surface J2or the third surface J3. If there are more than three active layers, the carrier confinement layer may be formed between two adjacent active layers, or the carrier confinement layer may be provided in an active layer or some active layers. Alternatively, the above-mentioned methods may be applied to the active region with multiple active layers according to actual needs. When the semiconductor laser diode is provided with one carrier confinement layer between two active layers, in principle, the material of the carrier confinement layer is at least one of the materials listed in Table 6. Embodiment 13 FIG.14dis a simplified schematic diagram showing an embodiment in which two carrier confinement layers are disposed in the epitaxial region between the two active layers when the active region includes two active layers. In Embodiment 13, the material of one of two carrier confinement layers is at least one material selected from Table 7, and the material of another carrier confinement layer is at least one material selected from Table. 8 Embodiment 14 FIGS.14e-14hare simplified schematic diagrams showing some representative embodiments in which the carrier confinement layer is disposed outside the active region when the active region includes two active layers. Embodiment 14 is based on Embodiment 9. Thus, please refer to the related examples of Embodiment 9 for the implementation of Embodiment 14. In addition, the carrier confinement layers may be provided above and below the active region A′. The material of one of two carrier confinement layers is at least one material selected from Table 7, and the material of another carrier confinement layer is at least one material selected from Table 8. Embodiment 15 FIG.14ais a schematic diagram of a principle embodiment. Please refer toFIG.15for an embodiment specifically applied to a VCSEL.FIG.15shows a schematic diagram of a preferred embodiment in which a carrier confinement layer is disposed between two active layers. As shown inFIG.15, the VCSEL includes two active layers20and21, the epitaxial region is disposed between these two active layers, and is between the second surface J2and the third surface J3. A preferred structure of the epitaxial region between two active layers20and21is shown inFIG.9, which includes a tunnel junction, an oxidation layer and a spacer layer. The carrier confinement layer CF is disposed in a part of the spacer layer263such that the spacer layer263is also provided between the third surface J3and the carrier confinement layer CF, but not limited thereto. For example, one surface of the carrier confinement layer CF may also be used as the surface in contact with the active layer21.FIG.16shows that the carrier confinement layer CF may also be provided in the spacer layer261near the second surface J2, and the carrier confinement layer CF is disposed in the middle of the spacer layer261. Please refer toFIG.17afor another possible embodiment ofFIG.14d; that is, the carrier confinement layers CF1and CF2are provided between two active layers20and21. AlthoughFIG.17ashows that the carrier confinement layers CF1and CF2are formed in the parts of the spacer layer261and the spacer layer263, respectively, the carrier confinement layers CF1and CF2may be formed in the entire spacer layer261and the entire spacer layer263, respectively. In an embodiment, as shown inFIG.17b, the carrier confinement layers CF1and CF2are provided above and below the active region A. AlthoughFIG.17bshows that the carrier confinement layers CF1and CF2are formed in the parts of the lower spacer layer103and the upper spacer layer104, respectively, the carrier confinement layers CF1and CF2may be formed in the entire lower spacer layer103and the entire upper spacer layer104, respectively. In some embodiments, a carrier confinement layer(s) may also be formed above and/or below any active layer. In some embodiments, as shown inFIG.17c, the carrier confinement layers CF2and CF3are provided between two adjacent active layers20and21, and the carrier confinement layers CF1and CF4are provided above and below the active region A. When holes are injected into the forth surface J4through the upper spacer layer104and electrons are injected into the active layer20from the first surface J1, the materials of the carrier confinement layers CF1and CF3are at least one material selected from Table 7, and the materials of the carrier confinement layers CF2and CF4are at least one material selected from Table 8. When electrons are injected into the fourth surface J4through the upper spacer layer104and holes are injected into the active layer20from the first surface J1, the materials of the carrier confinement layers CF1and CF3are at least one material selected from Table 8, and the materials of the carrier confinement layers CF2and CF4are at least one material selected from Table 7. Embodiment 16 Referring toFIG.18,FIG.18is a schematic diagram showing a multi-layer structure of an existing EEL. Referring toFIG.19a,FIG.19ashows a schematic diagram of an embodiment in which a first semiconductor layer is provided above and below an active layer of an EEL. Referring toFIG.19b,FIG.19bis a schematic diagram illustrating an embodiment in which a carrier confinement layer is provided above and below the active layer of the EEL. The semiconductor laser diode shown inFIG.18is an EEL3. As shown inFIG.18, the EEL3includes a GaAs substrate10and a multi-layer structure300. The multi-layer structure300includes a lower cladding layer301, a lower photoelectric confinement layer302(i.e., a lower separated confinement hetero structure), an active layer20, an upper photoelectric confinement layer303(i.e., an upper separated confinement hetero structure), an upper cladding layer304and an ohmic contact layer305. The active layer20is disposed between the lower photoelectric confinement layer302and the upper photoelectric confinement layer303. When the active layers of the EEL3and VCSEL1are quantum well structures, each embodiment of the first semiconductor layer implemented in the VCSEL1can also be directly implemented in the EEL3since the quantum well structures of the EEL3and VCSEL1are the same. For example, a part of or the entire of the barrier layer of the EEL3is provided with a first semiconductor layer, and the preferred materials for the well layers of the EEL3and VCSEL1are also the same. The disposing principles and exemplary embodiments of the first semiconductor layer are described in detail in Embodiment 1. Please refer thereto. Alternatively, a part of or the entire of the barrier layer of the EEL3is provided with a second semiconductor layer, and the preferred materials for the well layers and the intermediate layers of the EEL3are also the same as those of Embodiment 3. The disposing principles and exemplary embodiments of the second semiconductor layers are described in detail in Embodiment 3. Please refer thereto. Alternatively, an intermediate layer is further provided in the active layer of the EEL3. The disposing principles and exemplary embodiments of the intermediate layer are described in detail in Embodiment 2. Please refer thereto. Alternatively, a first (or second) semiconductor layer is provided between two adjacent active layers of the EEL3. The disposing principles and exemplary embodiments of the first (second) semiconductor layer in the multi-active layer are described in detail in Embodiment 6. Alternatively, in the EEL with multiple active layers, in addition to providing a tunnel junction between two adjacent layers, a spacer layer may be further formed. The preferred embodiment of the epitaxial region between two active layers is described in detail in Embodiment 6. Please refer thereto. Some of Embodiments 1-6 may also be applied to the active layer of the EEL. Although Embodiments 1-6 are mainly for strain compensation, they may also have carrier confinement effects. Similar to the VCSEL, the lasing wavelength of the EEL is above 700 nm or above 800 nm. If the strain compensation is the main consideration and the first semiconductor layer is disposed outside the active layer, in terms of the VCSEL, a first semiconductor layer is preferably provided in the lower spacer layer or the upper spacer layer of the VCSEL, or the lower spacer layer and the upper spacer layer are provided with a first semiconductor layer; in terms of the EEL, a first semiconductor layer is preferably provided in the lower photoelectric confinement layer or the upper photoelectric confinement layer, or the lower photoelectric confinement layer and the upper photoelectric confinement layer are provided with a first semiconductor as shown inFIG.19a. The first semiconductor layer may directly or indirectly contact the active layer. According to the type of strain and the strain compensation, the preferred material of the first semiconductor layer may be one of the materials selected from Table 1 or Table 4, when the selected material of the first semiconductor layer has the large bandgap and the first semiconductor layer is at the appropriate position, there may also have obvious carrier confinement effects. If the carrier confinement is the main consideration and the carrier confinement is disposed outside the active layer, in terms of the VCSEL, a carrier confinement layer is preferably provided in the lower spacer layer or the upper spacer layer of the VCSEL, or the lower spacer and the upper spacer layer are provided with a carrier confinement layer; in terms of the EEL, a carrier confinement layer is preferably provided in the lower photoelectric confinement layer or the upper photoelectric confinement layer, or the lower photoelectric confinement layer and the upper photoelectric confinement layer are provided with a carrier confinement layer as shown inFIG.19b. The carrier confinement layer may directly or indirectly contact the active layer. The preferred material of the carrier confinement layer may be one of the materials selected from Table 6. If the lattice constant of the selected material can be adjusted, the selected material may even provide appropriate strain to the active layer or the epitaxial layer of the VCSEL for strain compensation. Alternatively, in an EEL with multiple active layers, one or two carrier confinement layers may be provided outside the active regain, between two active layers or between any two adjacent active layers. Please refer to Embodiments 11-15 for specific implementation. In some embodiments, if the thickness of the lower photoelectric confinement layer or the upper photoelectric confinement layer is thin enough, the carrier confinement layer may also be disposed in the lower cladding layer or the upper cladding layer. In some embodiments, as shown inFIG.19b, the EEL includes two carrier confinement layers CF1and CF2. A part of the lower photoelectric confinement layer302is provided with the carrier confinement layer CF1, and a part of the upper photoelectric confinement layer303is provided with the carrier confinement layer CF2. Although two carrier confinement layers are shown inFIG.19b, a carrier confinement may be provided in a part of the lower photoelectric confinement layer, a part of the upper photoelectric confinement layer, the entire lower photoelectric confinement layer or the entire upper photoelectric confinement layer. The carrier confinement layer may also directly contact the active layer. Embodiment 17 In addition to the quantum well structures, the active regions of the VCSEL and EEL also have quantum dot structures (not shown). An embodiment of a quantum dot structure mainly includes a quantum dot, a wetting layer and a cap layer. In the quantum dot structure, the preferred material of the quantum dot or wetting layer is InGaAs, InAlGaAs, GaAsSb, GaAs, AlGaAs, AlGaAsSb, GaAsP, InGaAsP or any combination of the above materials. In terms of the VCSEL, in some embodiments, a spacer layer is provided above or below the quantum dot structure of the VCSEL, and in the embodiments of multiple quantum dot structures, a spacer layer may also be provided between two quantum dot structures. The first semiconductor layer (i.e., one of the 17 materials in Table 1) or the carrier confinement layer (i.e., one of the 17 materials in Table 6) may be formed in the cap layer, the spacer layer or both the cap layer and the spacer layer. A part of the cap layer or the spacer layer, the parts of the cap layer and the spacer layer, or the entire cap layer and the entire spacer layer may be provided with the first semiconductor layer or the carrier confinement layer. In some embodiments, a spacer layer is provided both above and below the quantum dot structure of the VCSEL. In terms of the EEL, in some embodiments, a lower photoelectric confinement layer is provided below the quantum dot structure of the EEL, or an upper photoelectric confinement layer is provided above the quantum dot structure of the EEL. In the embodiments of multiple quantum dot structures, a lower photoelectric confinement layer and/or an upper photoelectric confinement layer are provided between two quantum dot structures. A part of the cap layer, the lower photoelectric confinement layer or the upper photoelectric confinement layer, the entire cap layer, the entire lower photoelectric confinement layer or the entire upper photoelectric confinement layer may be provided with the first semiconductor layer or the carrier confinement layer. In some embodiments, the lower photoelectric confinement layer and the upper photoelectric confinement layer are provided above and below the quantum dot structure of the EEL. Alternatively, the cap layer, the lower photoelectric confinement layer and the upper photoelectric confinement layer are all provided with the first semiconductor layer or the carrier confinement layer. Embodiment 18 For a semiconductor laser diode such as a VCSEL or an EEL, the substrate material thereof may also be InP. Compared to a GaAs substrate, when a substrate of a semiconductor laser diode is an InP substrate, there are many choices for the material of each epitaxial layer on the substrate. For example, the material of the well layer and the barrier may be an aluminum-containing material or a non-aluminum-containing material, but the bandgaps of materials suitable for the epitaxial layer are relatively small such that it is necessary to further improve the high-temperature. For example, in the active layer (region), a carrier confinement layer may be provided in a barrier layer, some barrier layers or each barrier layer of the active layer, or one or more carrier confinement layers may also be provided in the upper epitaxial region and/or the lower epitaxial region. The disposing principles and preferred embodiments of the carrier confinement layer are described in Embodiments 11-15. Please refer thereto. It is important to note that since the material of the substrate is InP, the preferred materials for the carrier confinement layer may be InGaP, InAlGaP, InP, InAlAsP, AlAsSb, AlAsBi, AlGaAsSb, AlGaAsBi, AlPSb, AlPBi, InGaAsP or any combination of the above materials. The PL peak wavelength of InGaAsP does not exceed 900 nm. InGaP, InAlGaP, InP and InGaAsP in the above materials have a good holes confinement effect; InAlAsP, AlAsSb, AlAsBi, AlGaAsSb, AlGaAsBi, AlPSb, AlPBi have a good electrons confinement effect. The distance between the carrier confinement layer and the active layer usually does not exceed 120 nm, and the thickness of the carrier confinement layer is greater than 2 nm. Embodiments 19 and 20 as Well as Comparative Embodiment 1 In the present disclosure, the defect or dislocation in the epitaxial layer of the VCSEL is presented by X-ray topography (XRT) in Comparative Embodiment 1 and Embodiments 19 and 20 to show the improvement of the dislocation. In Comparative Embodiment 1 and Embodiments 19 and 20, XRT imaging is performed on the wafer center of the VCSEL epitaxial wafer. For the materials and thicknesses of the active layers, please refer to Table 9 to compare the embodiments of the present disclosure with the prior art (Comparative Embodiment 1). In Comparative Embodiment 1, there are an InGaAs well layer and a 6 nm AlGaAs barrier layer. In Embodiment 19, a 4 nm AlGaAs intermediate layer is provided in a GaAsP barrier layer with a thickness of 2 nm; that is, the thicknesses of two GaAsP barrier layers on both sides of the AlGaAs intermediate layer and adjacent to the well layer are 2 nm in total (the thickness of each GaAsP barrier layer is 1 nm). The Al contents of AlGaAs and AlGaAsP in Comparative Embodiment 1 and Embodiments 19 and 20 are 20%. TABLE 9well layerintermediate layerbarrier layerComparativeInGaAsn/aAlGaAsEmbodiment 17 nm6 nmEmbodiment 19InGaAsAlGaAsGaAsP7 nm4 nm2 nmEmbodiment 20InGaAsn/aAlGaAsP7 nm6 nm FIGS.20a-20cshow XRT images according to Comparative Embodiment 1 and Embodiments 19 and 20 of the present disclosure.FIG.20ais an XRT image of Comparative Embodiment 1, andFIGS.20band20care XRT images of Embodiments 19 and 20, respectively. By the XRT image of Comparative Embodiment 1, it can be observed that there are many obvious dark lines in Comparative Embodiment 1, that is, obvious dislocations. In contrast, according to the XRT image of Embodiment 19, although some dark lines may appear faintly in Embodiment 19, they are not obvious relative to Comparative Embodiment 1 while according to the XRT image of Embodiment 20, the dark lines (dislocations) are hardly observed in Embodiment 20. As such, compared with Comparative Embodiment 1, Embodiments 19 and 20 can reduce the dislocations in the epitaxial layer of the VCSEL. In Comparative Embodiment 1, InGaAs and AlGaAs are used as the materials of the well layer and the barrier layer. When the material of the substrate is GaAs, both InGaAs and AlGaAs will have compressive strain. Excessive compressive strain leads to more dislocations or defects in the epitaxial layer of the VCSEL, as shown by the multiple dark lines clearly visible in the XRT image ofFIG.20a. In Embodiment 19, by using a phosphorus-containing material such as GaAsP as the material of the barrier layer and AlGaAs as the material of the intermediate layer, the tensile strain is provided in the barrier layer to reduce the total strain of the active layers, thereby reducing the dislocations or defects of the epitaxial layer of the VCSEL and enhancing the ability of carrier confinement. In Embodiment 20, a phosphorus-containing material such as AlGaAsP is used as the material of the barrier layer, and the tensile strain is provided in the barrier layer. Therefore, compared to Comparative Embodiment 1, the defects or dislocations of the epitaxial layer of the VCSEL can be reduced. The XRT images of Embodiments 19 and 20 demonstrate that the use of a phosphorus-containing material (one of the 17 materials in Table 1) in a semiconductor laser diode can effectively reduce the dislocations or defects of the laser diode. Embodiments 21 and 22 as Well as Comparative Embodiment 2 FIG.21is a comparison diagram of the maximum power conversion efficiency (PCE MAX) of Embodiments 21 and 22 as well as Comparative Embodiment 2 at different temperatures. Comparative Embodiment 2 is a VCSEL with no carrier confinement layer for the holes between two active layers. In the VCSEL of Embodiment 21, an n type AlGaInP carrier confinement layer for the holes is provided between two active layers, and in the VCSEL of Embodiment 22, an n type InGaP carrier confinement layer for the holes is provided between two active layers. Please refer toFIG.15for the location of the carrier confinement layer. According to Embodiment 21 and 22, the holes is injected into the active layer21from the fourth surface J4, the electrons is injected into the active layer20from the first surface J1. As shown inFIG.21, at room temperature, Comparative Embodiment 2 is not significantly different from Embodiments 21 and 22 in the maximum power conversion efficiency. However, at high temperatures, compared to Comparative Embodiment 2, the maximum power conversion efficiency of embodiments 21 and 22 is significantly improved, and the higher the temperature increases, the more maximum power conversion efficiency of the embodiment 21 and 22 is increased. Embodiment 23 and Comparative Embodiment 3 FIG.22is a comparison diagram of the maximum power conversion efficiency of Embodiment 23 and Comparative Embodiment 3 at different temperatures. The VCSEL of Comparative Embodiment 3 includes five active layers and does not have a carrier confinement layer for the holes while the VCSEL of Embodiment 23 also includes five active layers and has an n type InGaP carrier confinement layer for the holes between each two adjacent active layers, Please refer toFIG.15for the location of the carrier confinement layer between each two adjacent active layers. According to Embodiment 23, the holes are injected into the active layer21from the fourth surface J4, the electrons are injected into the active layer20from the first surface J1. As shown inFIG.22, at room temperature, there is no significant difference between Comparative Embodiment 3 and Embodiment 23 in the maximum power conversion efficiency. However, at high temperatures, compared to the comparative embodiment 3, the maximum power conversion efficiency of embodiments 23 is significantly improved, the higher the temperature increases, the more the maximum power conversion efficiency of the embodiment 23 is increased. It can be seen from the above that a carrier confinement layer(s) for the holes disposed in two, three, four or more active layers has/have the effect of improving high-temperature performance of multi-junction VCSEL. In general, compared to electrons, holes are less active due to their greater effective mass. In the case where the VCSEL has only one active layer, the optical output power density of the VCSEL is relatively small such that the temperature of the active region or junction temperature is also relatively low. Therefore, the holes are relatively easily confined to the active layer. However, under the same operating current, since the optical output power density of the VCSEL with multiple active layers will increase significantly, the temperature of the active region or junction temperature will also increase significantly, and the holes will become more active. Consequently, the holes must be confined to maintain or further improve the optical performance of the VCSEL. In addition, the VCSEL with multiple active layers achieves high optical output power or high power conversion efficiency through the carrier recycling mechanism (the VCSEL with a single active layer does not have the carrier recycling mechanism). When the ability to confine holes between two active layers is not good, the carrier recycling effect will be poor, and the performance of the VCSEL with multiple active layers are also likely to deteriorate at high temperatures. In Embodiment 22 and Embodiment 23, since the InGaP carrier confinement layer for confining holes is provided, the maximum power conversion efficiency of the VCSEL with two active layers and the VCSEL with five active layers is significantly improved at high temperatures. Similarly, in Embodiment 21, the AlInGaP carrier confinement layer for confining hole is also provided. Therefore, at high temperatures, the maximum power conversion efficiency of the VCSEL with two active layers is also significantly improved. Embodiment 24 and Comparative Embodiment 4 FIG.23is a LIV curve of Embodiment 24 and Comparative Embodiment 4 measured at room temperature.FIG.24is a LIV curve of Embodiment 24 and Comparative Embodiment 4 measured at high temperature. The room temperature is about 25° C., and the high temperature is about 65° C. Embodiment 24 is an EEL with a carrier confinement layer for the holes, while Comparative Embodiment 4 is an EEL without a carrier confinement layer for the holes. Both Embodiment 24 and Comparative Embodiment 4 use an n type InP substrate. The material of the carrier confinement layer for the holes is n type InP (hereinafter referred to as a InP carrier confinement layer). The InP carrier confinement layer is disposed between the active layer and the lower photoelectric confinement layer, and one surface of the InP carrier confinement layer substantially contacts the active layer, that is, the active layer is formed directly on the InP carrier confinement layer. The material of the active layer is an aluminum-containing material and at least one portion of the lower photoelectric confinement layer substantially contacts the InP carrier confinement layer for the holes also include an aluminum-containing material. As shown inFIGS.23and24, compared with Comparative Embodiment 4 without a carrier confinement layer for the holes, Embodiment 24 has improved capability of carrier confinement at room temperature and high temperature such that the optical power (optical output power) and slope efficiency (SE) have also been improved. The slope efficiency is the slope of optical power (optical output power) and current (W/A). In the embodiment 24, the lasing wavelength of laser diode is about 1310 nm. When the aluminum-containing material is used as the materials of the barrier layer and the well layer in the active layer, the conduction band discontinuity is relatively high, and the valence band discontinuity is relatively small. As such, the height of the electron barrier of the active layer containing aluminum is usually high, but the height of the hole barrier is low. As a consequence, the hole confinement of the active layer is poor. By providing a phosphorus-containing carrier confinement layer above or below the active layer, since the phosphorus-containing carrier confinement layer and the aluminum-containing active layer can form a larger valence band discontinuity, the height of the hole barrier can be increased, and the hole confinement of the active layer is improved. Embodiment 24 is to dispose the n type InP carrier confinement layer between the aluminum-containing active layer and the aluminum-containing lower photoelectric confinement layer such that the originally lower valence band discontinuity can be significantly increased to increase the height of the hole barrier. Accordingly, the hole confinement of the active layer is improved, and at the same time, the conduction band discontinuities formed between the phosphorus-containing carrier confinement layer and the aluminum-containing active layer and between the phosphorus-containing carrier confinement layer and the aluminum-containing lower photoelectric confinement layer are not too large. Therefore, the electrons can be injected into the active layer from the lower photoelectric confinement layer without hindrance such that the resistance is not easy to increase, thereby improving the performance of the semiconductor laser diode. It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents. | 78,718 |
11862939 | DETAILED DESCRIPTION The present disclosure relates generally to optical techniques. More specifically, the present disclosure provides methods and devices using nonpolar, semi-polar, or polar c-plane oriented gallium and nitrogen containing substrates for optical applications. In an example, the present disclosure describes the fabrication of a high confinement factor UV laser diode composed of a low index upper and lower transparent conductive oxide [TCO] cladding layers. In an example, this method uses conventional planar growth of a LD epi-structure on either a nonpolar, semipolar, or polar c-plane GaN substrates. A transparent conductive oxide (TCO) is then deposited on the free epitaxial surface to form a transparent, conductive contact layer with an index of refraction lower than GaN or AlGaN films of compositions that can be grown fully strained at the thicknesses needed to provide sufficient confinement of the optical mode. Examples of TCOs are gallium oxide (Ga2O3) indium tin oxide (ITO) and zinc oxide (ZnO). ITO is the commercial standard for TCOs, and is used in a variety of fields including displays and solar cells where a semi-transparent electrical contact is desired. However, in the UV region ITO will be highly absorbing and thus may not be the ideal TCO for UV based laser diodes. ZnO offers the advantage of being a direct gap semiconductor with the same crystal structure as GaN and can be grown epitaxially on GaN at temperatures relatively low compared to growth temperatures of AlInGaN alloys. The bandgap of ZnO is also sufficiently large and similar to GaN (approx. 3.3 eV) that it will exhibit negligible band-edge absorption of visible and near UV wavelengths of light. ZnO can be deposited in a variety of ways such as metal organic chemical vapor deposition, other vapor deposition techniques, and from a solution. In a preferred embodiment, the transparent conductive oxides for UV laser diode cladding is a gallium oxide (for example beta Ga2O3 among other stoichiometries of gallium oxide). The direct absorption edge of above 4.7 eV or <263 nm makes gallium oxide an ideal candidate for UV laser cladding regions. Gallium oxide can be deposited either via sputtering, evaporation, or growth from aqueous solution or via a chemical or physical vapor deposition. Gallium oxide may be grown epitaxially on the GaN layers via metal organic chemical vapor deposition or molecular beam epitaxy among other growth techniques. Gallium oxide conductivity can be controlled either by introduction of extrinsic defects such as alloying with dopant species such as, but not limited to, nitrogen, zinc and silicon among others. Conductivity and band-gap can also be controlled by alloying gallium oxide with indium oxide, indium tin oxide alloys, zinc oxide, aluminum oxide and tin oxide among others. In some embodiments the TCO layers may consist of several or more layers of different composition. For example, a thin (less than 50 nm thick) but highly conductive gallium oxide contact layer may be used to provide good electrical contact while a thicker (100-200 nm) indium tin oxide layer is used to provide electrical conductivity and lower loss. The wafer is then bonded to a handle, with the free-surface of the TCO adjacent to the bonding interface. The bonding can either be direct, i.e. with the TCO in contact with the handle material, or indirect, i.e. with a bonding media disposed between the TCO and the handle material in order to improve the bonding characteristics. For example, this bonding media could be Au—Sn solder, CVD deposited SiO2, a polymer, CVD or chemically deposited polycrystalline semiconductor or metal, etc. Indirect bonding mechanisms may include thermocompression bonding, anodic bonding, glass frit bonding, bonding with an adhesive with the choice of bonding mechanism dependent on the nature of the bonding media. Thermocompression bonding involves bonding of wafers at elevated temperatures and pressures using a bonding media disposed between the TCO and handle wafer. The bonding media may be comprised of a number of different layers, but typically contain at least one layer (the bonding layer) that is composed of a relatively ductile material with a high surface diffusion rate. In many cases this material is either Au, Al, or Cu. The bonding stack may also include layers disposed between the bonding layer and the TCO or handle wafer that promote adhesion or act as diffusion barriers should the species in the TCO or handle wafer have a high solubility in the bonding layer material. For example an Au bonding layer on a Si wafer may result in diffusion of Si to the bonding interface, which would reduce the bonding strength. Inclusion of a diffusion barrier such as silicon oxide or nitride would limit this effect. Relatively thin layers of a second material may be applied on the top surface of the bonding layer in order to promote adhesion between the bonding layers disposed on the TCO and handle. Some bonding layer materials of lower ductility than gold (e.g. Al, Cu etc.) or which are deposited in a way that results in a rough film (for example electrolytic deposition) may require planarization or reduction in roughness via chemical or mechanical polishing before bonding, and reactive metals may require special cleaning steps to remove oxides or organic materials that may interfere with bonding. Metal layer stacks may be spatially non-uniform. For example, the initial layer of a bonding stack may be varied using lithography to provide alignment or fiducial marks that are visible from the backside of the transparent substrate. Thermocompressive bonding can be achieved at relatively low temperatures, typically below 500 degrees Celsius and above 200. Temperatures should be high enough to promote diffusivity between the bonding layers at the bonding interface, but not so high as to promote unintentional alloying of individual layers in each metal stack. Application of pressure enhances the bond rate, and leads to some elastic and plastic deformation of the metal stacks that brings them into better and more uniform contact. Optimal bond temperature, time and pressure will depend on the particular bond material, the roughness of the surfaces forming the bonding interface and the susceptibility to fracture of the handle wafer or damage to the device layers under load. The bonding interface need not be composed of the totality of the wafer surface. For example, rather than a blanket deposition of bonding metal, a lithographic process could be used to deposit metal in discontinuous areas separated by regions with no bonding metal. This may be advantageous in instances where defined regions of weak or no bonding aid later processing steps, or where an air gap is needed. One example of this would be in removal of the GaN substrate using wet etching of an epitaxially grown sacrificial layer. To access the sacrificial layer one must etch vias into either of the two surfaces of the epitaxial wafer, and preserving the wafer for re-use is most easily done if the vias are etched from the bonded side of the wafer. Once bonded, the etched vias result in channels that can conduct etching solution from the edges to the center of the bonded wafers, and therefore the areas of the substrate comprising the vias are not in intimate contact with the handle wafer such that a bond would form. The bonding media can also be an amorphous or glassy material bonded either in a reflow process or anodically. In anodic bonding the media is a glass with high ion content where mass transport of material is facilitated by the application of a large electric field. In reflow bonding the glass has a low melting point, and will form contact and a good bond under moderate pressures and temperatures. All glass bonds are relatively brittle, and require the coefficient of thermal expansion of the glass to be sufficiently close to the bonding partner wafers (i.e. the GaN wafer and the handle). Glasses in both cases could be deposited via vapor deposition or with a process involving spin on glass. In both cases the bonding areas could be limited in extent and with geometry defined by lithography or silk-screening process. Direct bonding between TCO deposited on both the GaN and handle wafers, of the TCO to the handle wafer or between the epitaxial GaN film and TCO deposited on the handle wafer would also be made at elevated temperatures and pressures. Here the bond is made by mass transport of the TCO, GaN and/or handle wafer species across the bonding interface. Due to the low ductility of TCOs the bonding surfaces must be significantly smoother than those needed in thermocompressive bonding of metals like gold. The embodiments of this invention will typically include a ridge of some kind to provide lateral index contrast that can confine the optical mode laterally. One embodiment would have the ridge etched into the epitaxially grown AlGaN cladding layers. In this case, it does not matter whether the ridge is etched into the p-type AlGaN layer before TCO deposition and bonding or into the n-type layer after bonding and removal of the substrate. In the former case, the TCO would have to be planarized somehow to provide a surface conducive to bonding unless a reflowable or plastically deformable bonding media is used which could accommodate large variations in height on the wafer surface. In the latter case bonding could potentially be done without further modifying the TCO layer. Planarization may be required in either case should the TCO deposition technique result in a sufficiently rough TCO layer as to hinder bonding to the handle wafer. In the case where a ridge is formed either partially or completely with the TCO, the patterned wafer could be bonded to the handle, leaving air gaps on either side of the ridge, thereby maximizing the index contrast between the ridge and surrounding materials. After p-side ridge processing, TCO is deposited as the p-contact. Following TCO deposition, the wafer is bonded p-side down to a carrier wafer and the bulk of the substrate is removed via laser lift-off or photochemical etching (PEC). This will require some kind of sacrificial layer on the n-side of the epi-structure. Laser ablation is a process where an above-band-gap emitting laser is used to decompose an absorbing sacrificial (Al,In,Ga)N layer by heating and inducing desorption of nitrogen. The remaining Ga sludge is then etched away using aqua regia or HCl. This technique can be used similarly to PEC etching in which a sacrificial material between the epitaxial device and the bulk substrate is etched/ablated away resulting in separation of the epitaxial structure and the substrate. The epitaxial film (already bonded to a handling wafer) can then be lapped and polished to achieve a planar surface. PEC etching is a photoassisted wet etch technique that can be used to etch GaN and its alloys. The process involves an above-band-gap excitation source and an electrochemical cell formed by the semiconductor and the electrolyte solution. In this case, the exposed (Al,In,Ga)N material surface acts as the anode, while a metal pad deposited on the semiconductor acts as the cathode. The above-band-gap light source generates electron-hole pairs in the semiconductor. Electrons are extracted from the semiconductor via the cathode while holes diffuse to the surface of material to form an oxide. Since the diffusion of holes to the surface requires the band bending at the surface to favor a collection of holes, PEC etching typically works only for n-type material although some methods have been developed for etching p-type material. The oxide is then dissolved by the electrolyte resulting in wet etching of the semiconductor. Different types of electrolyte including HCl, KOH, and HNO3have been shown to be effective in PEC etching of GaN and its alloys. The etch selectivity and etch rate can be optimized by selecting a favorable electrolyte. It is also possible to generate an external bias between the semiconductor and the cathode to assist with the PEC etching process. After laser lift-off, TCO is deposited as the n-contact. One version of this process flow using laser lift-off is described inFIGS.4(a) and4(b). Using this method, the substrate can be subsequently polished and reused for epitaxial growth. Sacrificial layers for laser lift-off are ones that can be included in the epitaxial structure between the light emitting layers and the substrate. These layers would have the properties of not inducing significant amounts of defects in the light emitting layers while having high optical absorption at the wavelengths used in the laser lift-off process. Some possible sacrificial layers include epitaxially grown layers that are fully strained to the substrate which are absorbing either due to bandgap, doping or point defectivity due to growth conditions, ion implanted layers where the implantation depth is well controlled and the implanted species and energy are tuned to maximize implantation damage at the sacrificial layer and patterned layers of foreign material which will act as masks for lateral epitaxial overgrowth. Sacrificial layers for lift-off of the substrate via photochemical etching would incorporate at a minimum a low-bandgap or doped layer that would absorb the pump light and have enhanced etch rate relative to the surrounding material. The sacrificial layer can be deposited epitaxially and their alloy composition and doping of these can be selected such that hole carrier lifetime and diffusion lengths are high. Defects that reduce hole carrier lifetimes and diffusion length must can be avoided by growing the sacrificial layers under growth conditions that promote high material crystalline quality. An example of a sacrificial layer would be InGaN layers that absorb at the wavelength of an external light source. An etch stop layer designed with very low etch rate to control the thickness of the cladding material remaining after substrate removal can also be incorporated to allow better control of the etch process. The etch properties of the etch stop layer can be controlled solely by or a combination of alloy composition and doping. A potential etch stop layer would an AlGaN layer with a bandgap higher than the external light source. Another potential etch stop layer is a highly doped n-type AlGaN or GaN layer with reduce minority carrier diffusion lengths and lifetime thereby dramatically reducing the etch rate of the etch stop material. PEC etching can be done before or after direct/indirect bonding of the free surface of the TCO to the handle material. In one case, the PEC etching is done after bonding of the p-side TCO to the handle material and the PEC etch releases the III-nitride epitaxial material from the gallium and nitrogen containing substrate. In another case, PEC etching of the sacrificial layer is done before bonding such that most of the sacrificial layer is removed and the III-nitride epitaxial material is held mechanically stable on the gallium and nitrogen containing substrate via small unetched regions. Such regions can be left unetched due to significant decrease in etch rates around dislocations or defects. TCO is then deposited on the epitaxial material and the TCO free surface is bonded to a handle wafer that can be composed of various materials. After bonding, mechanical force is applied to the handle wafer and gallium and nitrogen containing substrate to complete the release of III-nitride epitaxial material from the GaN substrate. Substrate removal can also be achieved by mechanical lapping and polishing or chemical-mechanical lapping and polishing, in which case the substrate cannot be recovered. In cases where the laterally confining structure is on the bonded p-side of the wafer the substrate need only be thinned enough to facilitate good cleaving, in which case lapping and polishing may be an ideal removal technique. In addition to providing ultra-high confinement active regions, this wafer bonding technique for the fabrication of Ga-based laser diodes can also lead to improved cleaved facet quality. Specifically, we describe a method for fabricating cleaved facets along a vertical plane for NP and SP ridge laser structures grown on bulk gallium and nitrogen containing substrates. Achieving a high quality cleaved facet for NP and SP ridge lasers can be extremely difficult due to the nature of the atomic bonding on the crystallographic planes that are orthogonal to a laser stripe oriented in the c-direction or the projection of the c-direction. In nonpolar m-plane, the desired ridge orientation is along the c-direction. Therefore, facets must be form on a crystallographic plane orthogonal to the c-direction (the c-plane). While this can be done in practice, the yield tends to be low and the facet qualities often vary. This is in part due to the high iconicity and bond strength on the c-plane, which make cleaving difficult. In some SP orientations, it is possible to achieve vertical cleavage planes that are orthogonal to the ridge direction—however, yields also tend to be low. In other SP orientations, vertical cleavage planes orthogonal to the ridge direction simply do not exist. Cleaving in these SP orientations often result in facets that are grossly angled. In this wafer bonding process invention the epitaxial laser structure grown on top of the gallium and nitrogen containing substrate is bonded p-side down on top of a handling wafer. This can be done before/after top-side processing depending on the desired resulting LD structure. The handling wafer material and crystal orientation is selected to have easily achievable vertical cleavage planes (examples of such materials include Si, GaAs, InP, etc.). The LD wafer and the handling wafer can be crystallographically aligned such that the preferable cleavage direction of the handling wafer coincides with the desired cleavage plane of the ridge LD structure. The LD wafer and the handling wafer are then directly or indirectly bonded together. After bonding, the bulk gallium and nitrogen containing substrate can be removed via PEC etching, laser ablation, or CMP. Since the resulting LD epitaxial film will be thin (<5 um), scribe marks should be penetrate the epi-film completely and into the bonding wafer. Forcing a clean cleave across the desired crystallographic plane should now be easy since there is limited amount of actual epi-material to break. This method may also allow fabrication of cleaved facet LDs on certain SP orientations that was previously not possible. The handling wafer can be selected from several possibilities including, but not limited to 6H-SiC, Si, sapphire, MgAl2O4spinel, MgO, ZnO, ScAlMgO4, GaAsInP, InP, GaAs, TiO2, Quartz, LiAlO2, AlN. The above described method can also be extended into the process for die expansion. Typical dimensions for laser cavity widths are 1-30 μm, while wire bonding pads are −100 μm wide. This means that if the wire bonding pad width restriction and mechanical handling considerations were eliminated from the gallium and nitrogen containing chip dimension between >3 and 100 times more laser diode die could be fabricated from a single epitaxial gallium and nitrogen containing wafer. This translates to a >3 to 100 times reduction in epitaxy and substrate costs. In certain device designs, the relatively large bonding pads are mechanically supported by the epitaxy wafer, although they make no use of the material properties of the semiconductor beyond structural support. The current invention allows a method for maximizing the number of gallium and nitrogen containing laser devices which can be fabricated from a given epitaxial area on a gallium and nitrogen containing substrate by spreading out the epitaxial material on a carrier wafer such that the wire bonding pads or other structural elements are mechanically supported by relatively inexpensive carrier wafer, while the light emitting regions remain fabricated from the necessary epitaxial material. In an embodiment, mesas of gallium and nitrogen containing laser diode epitaxy material are fabricated in a dense array on a gallium and nitrogen containing substrate. This pattern pitch will be referred to as the ‘first pitch’. Each of these mesas is a ‘die’. These die are then transferred to a carrier wafer at a second pitch where the second pitch is greater than the first pitch. The second die pitch allows for easy mechanical handling and room for wire bonding pads positioned in the regions of carrier wafer in-between epitaxy mesas, enabling a greater number of laser diodes to be fabricated from a given gallium and nitrogen containing substrate and overlying epitaxy material. This is referred to as “die expansion,” or other terms consistent with ordinary meaning for one of ordinary skill in the art. FIG.9—Side view illustrations of gallium and nitrogen containing epitaxial wafer100before the die expansion process and carrier wafer1206after the die expansion process. This figure demonstrates a roughly five times expansion and thus five times improvement in the number of laser diodes which can be fabricated from a single gallium and nitrogen containing substrate and overlying epitaxial material. Typical epitaxial and processing layers are included for example purposes and are n-AlGaN for n-side waveguide and/or cladding layers1201, active region1202, p-AlGaN for p-side waveguide or cladding layers1203, insulating layers1204, and contact/pad layers105. Additionally, a sacrificial region1207and bonding material1208are used during the die expansion process. In another embodiment, die expansion can be used to fabricate “ridge-less” lasers in which the epitaxial material of the entire or almost entire mesa stripe is utilized in the laser. This differs from the traditional ridge laser structure where a ridge is etched into the epitaxial material to form an index guided laser. In this embodiment for a ridge-less laser, the entire mesa is used as a gain guided laser structure. First mesas are etched and transferred onto a carrier wafer via direct/indirect bonding. The gallium and nitrogen containing substrate is removed, leaving the etched mesas on the carrier wafer at a die pitch larger than the original die pitch on the gallium and nitrogen containing carrier wafer. Dielectric material is deposited on the sidewalls of the mesa to insulate the p- and n-contacts. The dielectric material does not cover the entirety of the gallium and nitrogen containing p-contact surface. Metal or TCO is deposited on the gallium and nitrogen containing p-contact surface to form the p-contacts. This is an exemplary process in which a ridge-less LD structure may be formed through the invention described in this patent. FIG.8cross-section schematic of a ridge-less laser structure fabricated using the current invention. The epitaxial material806is transferred onto a carrier wafer801using the techniques discussed in the current invention. Bonding of the epitaxial material806to the carrier wafer801can be done so via indirect metal802to metal802thermo-compressive bonding. The epitaxial material is cladded on the p- and n-side using TCO804to provide high modal confinement in the MQW active region807. Insulating material803is deposited on the sidewalls of the mesa to insulate the p- and n-contacts. Top-side metal pad contact805is formed on top of the top side TCO804. In an example, the present techniques provide for a method for fabricating a laser diode device. The method includes providing a gallium and nitrogen containing substrate member comprising a surface region, a release material overlying the surface region, an n-type gallium and nitrogen containing material such as AlGaN; an active region overlying the n-type gallium and nitrogen containing material, an electron blocking layer overlying the active region, a p-type gallium and nitrogen containing material such as AlGaN; and an interface region overlying the p-type gallium and nitrogen containing material. The method includes bonding the interface region to a handle substrate; and subjecting the release material to an energy source, using at least PEC etching, to initiate release of the gallium and nitrogen containing substrate member, while maintaining attachment of the handle substrate via the interface region. The method also includes forming a contact region to either or both the n-type gallium and nitrogen containing material or the p-type gallium and nitrogen containing material. Referring now back toFIG.6a—The epitaxial LD structure and the GaN substrate may be bonded directly or indirectly to a handling wafer. Direct wafer bonding is bonding without the application of intermediate layers (i.e., GaN directly onto GaAs). Indirect wafer bonding is bonding with the application of an intermediate adhesion layer. When the adhesion layer material is comprised of a metal alloy, the process is often referred to as eutectic bonding. FIG.6b—For the cleave to translate from the bonding wafer into the thin GaN LD membrane, the two wafers must be crystallographically aligned before bonding. Here, the GaN (0001) plane (or the [11-20] direction) for an m-plane LD is aligned with InP (011) plane (or [0-11] direction). FIG.7—Wafer bonding is sensitive to surface roughness and topography. Smooth surfaces are typically required for high yield direct wafer bonding. Direct wafer bonding of a handling wafer onto the ridge side of the LD structure would therefore likely require a pre-etched handling wafer. The pre-etched handling wafer would allow the wafer bonding to occur only on the exposed AlGaN ridge and not on the contact pads. This is depicted in the cross-sectional schematic inFIG.3a. The use of a pre-etched handling wafer would also be applicable in the case where indirect bonding is used (FIG.3b). Note, this pre-etched handling wafer is only necessary if there is exists a rough surface topography that may degrade the wafer bonding yield. A non-etched handling wafer may be used if bonding between two planar wafers is desired. FIG.9is a side view illustration of gallium and nitrogen containing epitaxial wafer100before the die expansion process and carrier wafer106after the die expansion process. This figure demonstrates a roughly five times expansion and thus a five times increase in the number of laser diodes that can be fabricated from a single gallium and nitrogen containing substrate and overlying epitaxial material. Typical epitaxial and processing layers are included for example purposes and include AlGaN and/or n-AlGaN for n-side waveguiding and/or cladding layers101, active region102, AlGaN and/or p-AlGaN for p-side waveguiding or cladding regions103, insulating layers104, and contact/pad layers105. Additionally, a sacrificial region107and bonding material108are used during the die expansion process. FIG.10is a simplified top view of a selective area bonding process and illustrates a die expansion process via selective area bonding. The original gallium and nitrogen containing epitaxial wafer201has had individual die of epitaxial material and release layers defined through processing. Individual epitaxial material die are labeled202and are spaced at pitch1. A round carrier wafer200has been prepared with patterned bonding pads203. These bonding pads are spaced at pitch2, which is an even multiple of pitch1such that selected sets of epitaxial die can be bonded in each iteration of the selective area bonding process. The selective area bonding process iterations continue until all epitaxial die have been transferred to the carrier wafer204. The gallium and nitrogen containing epitaxy substrate201can now optionally be prepared for reuse. In an example,FIG.11is a simplified diagram of process flow for epitaxial preparation including a side view illustration of an example epitaxy preparation process flow for the die expansion process. The gallium and nitrogen containing epitaxy substrate100and overlying epitaxial material are defined into individual die, bonding material108is deposited, and sacrificial regions107are undercut. Typical epitaxial layers are included for example purposes and are AlGaN and/or n-AlGaN for n-side waveguide or cladding layers101, active region102, and AlGaN and/or p-AlGaN for p-side waveguide regions and/or cladding regions103. In an example,FIG.12is a simplified illustration of a side view of a selective area bonding process in an example. Prepared gallium and nitrogen containing epitaxial wafer100and prepared carrier wafer106are the starting components of this process. The first selective area bonding iteration transfers a fraction of the epitaxial die, with additional iterations repeated as needed to transfer all epitaxial die. Once the die expansion process is completed, state of the art laser processing can continue on the carrier wafer. Typical epitaxial and processing layers are included for example purposes and are AlGaN and/or n-AlGaN for n-side waveguide and/or cladding layers101, active region102, p-AlGaN or AlGaN for p-side waveguide and/or cladding regions103, insulating layers104and contact/pad layers105. Additionally, a sacrificial region107and bonding material108are used during the die expansion process. In an example,FIG.13is a simplified diagram of an epitaxy preparation process with active region protection. Shown is a side view illustration of an alternative epitaxial wafer preparation process flow during which sidewall passivation is used to protect the active region during any PEC undercut etch steps. This process flow allows for a wider selection of sacrificial region materials and compositions. Typical substrate, epitaxial, and processing layers are included for example purposes and are the gallium and nitrogen containing substrate100, n-AlGaN and/or AlGaN for n-side cladding and/or waveguiding layers101, active region102, AlGaN and/or p-AlGaN for p-side waveguiding and/or cladding regions103, insulating layers104and contact/pad layers105. Additionally, a sacrificial region107and bonding material108are used during the die expansion process. In an example,FIG.14is a simplified diagram of epitaxy preparation process flow with active region protection and ridge formation before bonding. Shown is a side view illustration of an alternative epitaxial wafer preparation process flow during which sidewall passivation is used to protect the active region during any PEC undercut etch steps and laser ridges are defined on the denser epitaxial wafer before transfer. This process flow potentially allows cost saving by performing additional processing steps on the denser epitaxial wafer. Typical substrate, epitaxial, and processing layers are included for example purposes and are the gallium and nitrogen containing substrate100, AlGaN and/or n-AlGaN for n-side waveguide and/or cladding layers101, active region102, AlGaN and/or p-AlGaN for p-side waveguide and/or cladding layers103, insulating layers104and contact/pad layers105. Additionally, a sacrificial region107and bonding material108are used during the die expansion process. FIG.15is a simplified example of anchored PEC undercut (top-view). Shown is a top view of an alternative release process during the selective area bonding of narrow mesas. In this embodiment a top down etch is used to etch away the area300, followed by the deposition of bonding metal303. A PEC etch is then used to undercut the region301, which is wider than the lateral etch distance of the sacrificial layer. The sacrificial region302remains intact and serves as a mechanical support during the selective area bonding process. Anchors such as these can be placed at the ends of narrow mesas as in the “dog-bone” version. Anchors can also be placed at the sides of mesas (see peninsular anchor) such that they are attached to the mesa via a narrow connection304, which is undercut and will break preferentially during transfer. Geometric features that act as stress concentrators305can be added to the anchors to further restrict where breaking will occur. The bond media can also be partially extended onto the anchor to prevent breakage near the mesa. FIG.16is a simplified view of anchored PEC undercut (side-view) in an example. Shown is a side view illustration of the anchored PEC undercut. Posts of sacrificial region are included at each end of the epitaxial die for mechanical support until the bonding process is completed. After bonding the epitaxial material will cleave at the unsupported thin film region between the bond pads and intact sacrificial regions, enabling the selective area bonding process. Typical epitaxial and processing layers are included for example purposes and are AlGaN and/or n-AlGaN for n-side waveguide and/or cladding layers101, active region102, AlGaN and/or p-AlGaN for p-side waveguide and/or cladding layers103, insulating layers104and contact/pad layers105. Additionally, a sacrificial region107and bonding material108are used during the die expansion process. Epitaxial material is transferred from the gallium and nitrogen containing epitaxial wafer100to the carrier wafer106. Further details of the present method and structures can be found more particularly below. FIG.17is top view of a selective area bonding process with die expansion in two dimensions in an example. The substrate901is patterned with transferrable die903. The carrier wafer902is patterned with bond pads904at both a second and fourth pitch that are larger than the die pitches on the substrate. After the first bonding, a subset of the laser die is transferred to the carrier. After the second bonding a complete row of die are transferred. In an embodiment, a laser diodes emitting in the ultra violet at 350 nm is grown epitaxially on GaN substrates.FIG.4ashows a schematic cross section of the structure, which consists of an n-type buffer layer of GaN overlaying the substrate, a sacrificial region consisting of an In0.1Ga0.9N/GaN multiquantum well structure, an Al0.2Ga0.8N n-type cladding overlaying the sacrificial layers, an active region comprised of an Al0.2Ga0.8N/GaN multiquantum well structure overlaid by an Al0.3Ga0.8N electron blocking layer overlaid by an Al0.2Ga0.8N p-type cladding region. The Al0.2Ga0.8N cladding regions can vary in thickness from 50 to 250 nm. The sacrificial region InGaN wells can vary in number from 1 to 10 with well width varying from 1 to 6 nanometers such that the sacrificial layer absorbs light of wavelength longer than 405 nm. The active region wells are composed of GaN and the barriers of Al0.2Ga0.8N, which matches the composition and bandgap of the cladding. In an embodiment, a laser diodes emitting in the ultra violet at 350 nm is grown epitaxially on GaN substrates using AlInGaN cladding. This has the advantage of allowing for the growth of thick cladding layers due to the closer lattice matching between GaN and various compositions of AlInGaN.FIG.4bshows a schematic cross section of the structure, which consists of an n-type buffer layer of GaN overlaying the substrate, a sacrificial region consisting of an In0.1Ga0.9N/GaN multiquantum well structure, an (Al1-xInxN)y(GaN)1-ywhere x=0.17±3 and y=0.3 n-type cladding overlaying the sacrificial layers, an active region comprised of an Al0.2Ga0.8N/GaN multiquantum well structure overlaid by an Al0.3Ga0.8N electron blocking layer overlaid by an (Al1-xInxN)y(GaN)1-ywhere x=0.17±3 and y=0.3 p-type cladding region. The AlInGaN cladding regions can vary in thickness from 50 to 250 nm. The sacrificial region InGaN wells can vary in number from 1 to 10 with well width varying from 1 to 6 nanometers such that the sacrificial layer absorbs light of wavelength longer than 405 nm. The active region wells are composed of GaN and the barriers of Al0.2Ga0.8N, which matches the composition and bandgap of the cladding. In an embodiment, a laser diodes emitting in the ultra violet at 300 nm is grown epitaxially on GaN substrates.FIG.4cshows a schematic cross section of the structure, which consists of an n-type buffer layer of GaN overlaying the substrate, a sacrificial region consisting of an In0.1Ga0.9N/GaN multiquantum well structure, an Al0.45Ga0.55N n-type cladding overlaying the sacrificial layers, an active region comprised of an Al0.35Ga0.65N/Al0.45Ga0.55N multiquantum well structure overlaid by an Al0.55Ga0.45N electron blocking layer overlaid by an Al0.45Ga0.55N p-type cladding region. The Al0.45Ga0.55N cladding regions can vary in thickness from 50 to 250 nm. The sacrificial region InGaN wells can vary in number from 1 to 10 with well width varying from 1 to 6 nanometers such that the sacrificial layer absorbs light of wavelength longer than 405 nm. The active region wells are composed of Al0.45Ga0.55N and the barriers of Al0.35Ga0.65N, which matches the composition and bandgap of the cladding. In an embodiment, a laser diodes emitting in the ultra violet at 300 nm is grown epitaxially on GaN substrates using AlInGaN cladding. This has the advantage of allowing for the growth of thick cladding layers due to the closer lattice matching between GaN and various compositions of AlInGaN.FIG.4dshows a schematic cross section of the structure, which consists of an n-type buffer layer of GaN overlaying the substrate, a sacrificial region consisting of an In0.1Ga0.9N/GaN multiquantum well structure, an (Al1-xInxN)y(GaN)1-ywhere x=0.17±3 and y=0.78 n-type cladding overlaying the sacrificial layers, an active region comprised of an Al0.35Ga0.65V Al0.45Ga0.55N multiquantum well structure overlaid by an Al0.55Ga0.45N electron blocking layer overlaid by an (Al1-xInxN)y(GaN)1-ywhere x=0.17±3 and y=0.78 p-type cladding region. The AlInGaN cladding regions can vary in thickness from 50 to 250 nm. The sacrificial region InGaN wells can vary in number from 1 to 10 with well width varying from 1 to 6 nanometers such that the sacrificial layer absorbs light of wavelength longer than 405 nm. The active region wells are composed of Al0.35Ga0.65N and the barriers of Al0.45Ga0.55N, which matches the composition and bandgap of the cladding. In an embodiment, a laser diodes emitting in the ultra violet at 280 nm is grown epitaxially on GaN substrates.FIG.4eshows a schematic cross section of the structure, which consists of an n-type buffer layer of GaN overlaying the substrate, a sacrificial region consisting of an In0.1Ga0.9N/GaN multiquantum well structure, an Al0.55Ga0.35N n-type cladding overlaying the sacrificial layers, an active region comprised of an Al0.45Ga0.55N/Al0.55Ga0.45N multiquantum well structure overlaid by an Al0.65Ga0.35N electron blocking layer overlaid by an Al0.55Ga0.35N p-type cladding region. The Al0.55Ga0.35N cladding regions can vary in thickness from 50 to 250 nm. The sacrificial region InGaN wells can vary in number from 1 to 10 with well width varying from 1 to 6 nanometers such that the sacrificial layer absorbs light of wavelength longer than 405 nm. The active region wells are composed of Al0.45Ga0.55N and the barriers of Al0.55Ga0.45N, which matches the composition and bandgap of the cladding. In an embodiment, a laser diodes emitting in the ultra violet at 280 nm is grown epitaxially on GaN substrates using AlInN cladding. This has the advantage of allowing for the growth of thick cladding layers due to the closer lattice matching between GaN and various compositions of AlInGaN.FIG.4fshows a schematic cross section of the structure, which consists of an n-type buffer layer of GaN overlaying the substrate, a sacrificial region consisting of an In0.1Ga0.9N/GaN multiquantum well structure, an Al1-xInxN where x=0.17±3 n-type cladding overlaying the sacrificial layers, an active region comprised of an Al0.45Ga0.55N/Al0.55Ga0.45N multiquantum well structure overlaid by an Al0.65Ga0.35N electron blocking layer overlaid by an Al1-xInxN where x=0.17±3 p-type cladding region. The AlInGaN cladding regions can vary in thickness from 50 to 250 nm. The sacrificial region InGaN wells can vary in number from 1 to 10 with well width varying from 1 to 6 nanometers such that the sacrificial layer absorbs light of wavelength longer than 405 nm. The active region wells are composed of Al0.45Ga0.55N and the barriers of Al0.55Ga0.45N, which matches the composition and bandgap of the cladding. In an example, the present invention can be applied to a variety of applications, including defense and security, biomedical instrumentation and treatment, germicidal disinfection, water treatment, chemical curing, industrial cutting and shaping, industrial metrology, and materials processing. In the field of defense and security, for example, UV lasers are used for remote biological and chemical agent detection. In this application, laser based Raman spectroscopy is utilized to measure molecular vibrations to quickly and accurately identify unknown substances. UV lasers have the optimal wavelength for Raman spectroscopy at stand-off distances, but the current UV-based tactical detection systems are large and expensive and have limited functionality. In addition to bio-chem agent detection, UV lasers are used for environmental sensing, atmosphere control and monitoring, pollution monitoring, and other ecological monitoring since a myriad of different compounds are detectable. Other applications within defense and security include forensics, detection of altered documents, counterfeit currency detection, and fingerprint detection. In these applications, the deep UV laser excites fluorescence in the samples, revealing information that is not detectable with visible illumination. In biomedicine, UV lasers are used in medical diagnostics applications utilizing fluorescence spectroscopy and Raman spectroscopy to detect and characterize constituents of particular samples. Examples include confocal microscopes, spectrophotometers, flow cytometers, gel electrophoresis, and DNA analysis equipment. In addition to diagnostics, UV lasers are used in medical therapies and procedures because UV light is well absorbed by biological matter and organic compounds. Rather than burning or cutting material, pulsed UV lasers can deposit enough energy to disrupt the molecular bonds of the surface tissue, which effectively disintegrates into the air in a tightly controlled manner through ablation rather than burning. Thus UV lasers have the useful property that they can remove exceptionally fine layers of surface material with almost no heating or change to the remainder of the material, which is left intact. These properties make UV lasers well suited to precision micromachining organic material (including certain polymers and plastics), or delicate surgeries such as eye surgery LASIK. UV lasers also have applications in treating a variety of dermatological conditions including psoriasis, vitiligo, atopic dermatitis, alopecia areata and leukoderma, all of which have particular absorptions in the UV range. Additionally, UV lasers can be used for germicidal disinfection applications deep UV light at particular wavelengths kill microorganisms in food, air, and water (purification). The UV laser light is effective in destroying the nucleic acids in these organisms so that their DNA is disrupted by the UV radiation, leaving them unable to perform vital cellular functions. The wavelength of UV that causes this effect is rare on Earth as the atmosphere blocks it. As a result, using UV laser devices in certain environments like circulating air or water systems creates a deadly effect on micro-organisms such as pathogens, viruses and molds that are in these environments. Coupled with a filtration system, UV lasers can remove harmful micro-organisms from these environments. The application of UV light to disinfection has been an accepted practice since the mid-20th century. It has been used primarily in medical sanitation and sterile work facilities. Increasingly it was employed to sterilize drinking and wastewater, as the holding facilities were enclosed and could be circulated to ensure a higher exposure to the UV. In recent years UV sterilization has found renewed application in air sanitation. In industrial applications, UV lasers are used in inspection and metrology since the imaging resolution increases with decreasing wavelength of the illumination source. Semiconductor wafer inspection equipment utilizes UV lasers for basic illumination as well as scattering and elipsometry. Additionally, UV fluorescence is used in industrial inspection. Lasers in the UV range also permit various types of non-thermal (“cold”) processing. These processes range from curing of materials such as epoxies, curing of paints and inks in industrial printing. UV lasers also enable the removal of sub-micrometer-thick layers of material, marking an object by UV photon induced color changes of the surface, surface processing including annealing, doping and planarization, Chemical Vapor Deposition (CVD), writing Bragg gratings into optical fibers. UV lasers are widely used in high-resolution photolithography machines, one of the critical technologies required for microelectronic chip manufacturing. Current state-of-the-art lithography tools use deep ultraviolet (DUV) light from the KrF and ArF excimer lasers with wavelengths of 248 and 193 nanometers (the dominant lithography technology today is thus also called “excimer laser lithography” which has enabled transistor feature sizes to shrink below 45 nanometers. Excimer laser lithography has thus played a critical role in the continued advance of the so-called Moore's law for the last 20 years. As shown, the present device can be enclosed in a suitable package. Such package can include those such as in TO-38 and TO-56 headers. Other suitable package designs and methods can also exist, such as TO-9 or flat packs where fiber optic coupling is required and even non-standard packaging. In a specific embodiment, the present device can be implemented in a co-packaging configuration such as those described in U.S. Publication No. 2010/0302464, which is incorporated by reference in its entirety. In other embodiments, the present laser device can be configured in a variety of applications. Such applications include laser displays, metrology, communications, health care and surgery, information technology, and others. As an example, the present laser device can be provided in a laser display such as those described in U.S. Publication No. 2010/0302464, which is incorporated by reference in its entirety. Additionally, the present laser device can also include elements of U.S. Provisional Application No. 61/889,955 filed on Oct. 11, 2013, which is incorporated by reference in its entirety. While the above is a full description of the specific embodiments, various modifications, alternative constructions and equivalents may be used. As an example, the packaged device can include any combination of elements described above, as well as outside of the present specification. As used herein, the term “substrate” can mean the bulk substrate or can include overlying growth structures such as a gallium and nitrogen containing epitaxial region, or functional regions such as n-type GaN, combinations, and the like. Additionally, the examples illustrates two waveguide structures in normal configurations, there can be variations, e.g., other angles and polarizations. For semi-polar, the present method and structure includes a stripe oriented perpendicular to the c-axis, an in-plane polarized mode is not an Eigen-mode of the waveguide. The polarization rotates to elliptic (if the crystal angle is not exactly 45 degrees, in that special case the polarization would rotate but be linear, like in a half-wave plate). The polarization will of course not rotate toward the propagation direction, which has no interaction with the Al band. The length of the a-axis stripe determines which polarization comes out at the next mirror. Although the embodiments above have been described in terms of a laser diode, the methods and device structures can also be applied to any light emitting diode device. Therefore, the above description and illustrations should not be taken as limiting the scope of the present invention, which is defined by the appended claims. | 48,432 |
11862940 | DETAILED DESCRIPTION The present invention provides a fiber-delivered phosphor-emitted white light system and method of making the same. Merely by examples, the invention provides laser pumped phosphor light sources from gallium and nitrogen containing laser diodes, white light source integrated with a fiber attached phosphor in packaging and pump-light delivering configuration. The invention is applicable to many applications including dynamic lighting devices and methods, LIDAR, LiFi, and visible light communication devices and methods, and various combinations of above in applications of general lighting, commercial lighting and display, automotive lighting and communication, defense and security, industrial processing, and internet communications, and others. As background, while LED-based light sources offer great advantages over incandescent based sources, there are still challenges and limitations associated with LED device physics. The first limitation is the so called “droop” phenomenon that plagues GaN based LEDs. The droop effect leads to power rollover with increased current density, which forces LEDs to hit peak external quantum efficiency at very low current densities in the 10-200 A/cm2range.FIG.1shows a schematic diagram of the relationship between internal quantum efficiency [IQE] and carrier concentration in the light emitting layers of a light emitting diode [LED] and light-emitting devices where stimulated emission is significant such as laser diodes [LDs] or super-luminescent LEDs. IQE is defined as the ratio of the radiative recombination rate to the total recombination rate in the device. At low carrier concentrations Shockley-Reed-Hall recombination at crystal defects dominates recombination rates such that IQE is low. At moderate carrier concentrations, spontaneous radiative recombination dominates such that IQE is relatively high. At high carrier concentrations, non-radiative auger recombination dominates such that IQE is again relatively low. In devices such as LDs or SLEDs, stimulated emission at very high carrier densities leads to a fourth regime where IQE is relatively high.FIG.2shows a plot of the external quantum efficiency [EQE] for a typical blue LED and for a high power blue laser diode. EQE is defined as the product of the IQE and the fraction of generated photons that are able to exit the device. While the blue LED achieves a very high EQE at very low current densities, it exhibits very low EQE at high current densities due to the dominance of auger recombination at high current densities. The LD, however, is dominated by stimulated emission at high current densities, and exhibits very high EQE. At low current densities, the LD has relatively poor EQE due to re-absorption of photons in the device. Thus, to maximize efficiency of the LED based light source, the current density must be limited to low values where the light output is also limited. The result is low output power per unit area of LED die [flux], which forces the use large LED die areas to meet the brightness requirements for most applications. For example, a typical LED based light bulb will require 3 mm2to 30 mm2of epi area. A second limitation of LEDs is also related to their brightness, more specifically it is related to their spatial brightness. A conventional high brightness LED emits ˜1 W per mm2of epi area. With some advances and breakthrough this can be increased up to 5-10× to 5-10 W per mm2of epi area. Finally, LEDs fabricated on conventional c-plane GaN suffer from strong internal polarization fields, which spatially separate the electron and hole wave functions and lead to poor radiative recombination efficiency. Since this phenomenon becomes more pronounced in InGaN layers with increased indium content for increased wavelength emission, extending the performance of UV or blue GaN-based LEDs to the blue-green or green regime has been difficult. An exciting new class of solid-state lighting based on laser diodes is rapidly emerging. Like an LED, a laser diode is a two-lead semiconductor light source that that emits electromagnetic radiation. However, unlike the output from an LED that is primarily spontaneous emission, the output of a laser diode is comprised primarily of stimulated emission. The laser diode contains a gain medium that functions to provide emission through the recombination of electron-hole pairs and a cavity region that functions as a resonator for the emission from the gain medium. When a suitable voltage is applied to the leads to sufficiently pump the gain medium, the cavity losses are overcome by the gain and the laser diode reaches the so-called threshold condition, wherein a steep increase in the light output versus current input characteristic is observed. At the threshold condition, the carrier density clamps and stimulated emission dominates the emission. Since the droop phenomenon that plagues LEDs is dependent on carrier density, the clamped carrier density within laser diodes provides a solution to the droop challenge. Further, laser diodes emit highly directional and coherent light with orders of magnitude higher spatial brightness than LEDs. For example, a commercially available edge emitting GaN-based laser diode can reliably produce about 2 W of power in an aperture that is 15 μm wide by about 0.5 μm tall, which equates to over 250,000 W/mm2. This spatial brightness is over 5 orders of magnitude higher than LEDs or put another way, 10,000 times brighter than an LED. Based on essentially all the pioneering work on GaN LEDs, visible laser diodes based on GaN technology have rapidly emerged over the past 20 years. Currently the only viable direct blue and green laser diode structures are fabricated from the wurtzite AlGaInN material system. The manufacturing of light emitting diodes from GaN related materials is dominated by the heteroepitaxial growth of GaN on foreign substrates such as Si, SiC and sapphire. Laser diode devices operate at such high current densities that the crystalline defects associated with heteroepitaxial growth are not acceptable. Because of this, very low defect-density, free-standing GaN substrates have become the substrate of choice for GaN laser diode manufacturing. Unfortunately, such bulk GaN substrates are costly and not widely available in large diameters. For example, 2″ diameter is the most common laser-quality bulk GaN c-plane substrate size today with recent progress enabling 4″ diameter, which are still relatively small compared to the 6″ and greater diameters that are commercially available for mature substrate technologies. Further details of the present invention can be found throughout the present specification and more particularly below. Additional benefits are achieved over pre-existing techniques using the present invention. In particular, the present invention enables a cost-effective laser-based remotely delivered white light source. In a specific embodiment, the present optical device can be manufactured in a relatively simple and cost-effective manner. Depending upon the embodiment, the present apparatus and method can be manufactured using conventional materials and/or methods according to one of ordinary skill in the art. In some embodiments of this invention the gallium and nitrogen containing laser diode source is based on c-plane gallium nitride material and in other embodiments the laser diode is based on nonpolar or semipolar gallium and nitride material. In one embodiment the white source is configured from a laser chip on submount (CoS) with the laser light being delivered by a waveguide to a phosphor supported on a remotely disposed submount and/or a remote support member to form a remotely-delivered white light source. In some embodiments, the waveguide is a semiconductor waveguide integrated on a intermediate submount coupled with the CoS. In some embodiments the waveguide includes an optical fiber disposed substantially free in space or in custom layout, making the white light source a fiber-delivered white light source. In some embodiments the white light source includes beam collimation and focus elements to couple the laser light into the waveguide or fiber. In some embodiments, the white light source includes multiple laser chips either independently or co-packaged in a same package caseand the phosphor member are supported in a separate submont heatsink packaged in a remote case. In some embodiments there could be additional beam shaping optical elements included for shaping or controlling the white light out of the phosphor. In various embodiments, the laser device and phosphor device are separately packaged or mounted on respective support member and the phosphor materials are operated in a reflective mode to result in a white emitting laser-based light source. In additional various embodiments, the electromagnetic radiation from the laser device is remotely coupled to the phosphor device through means such as free space coupling or coupling with a waveguide such as a fiber optic cable or other solid waveguide material, and wherein the phosphor materials are operated in a reflective mode to result in a white emitting laser-based light source. Merely by way of example, the invention can be applied to applications such as white lighting, white spot lighting, flash lights, automobile headlights, all-terrain vehicle lighting, flash sources such as camera flashes, light sources used in recreational sports such as biking, surfing, running, racing, boating, light sources used for drones, planes, robots, other mobile or robotic applications, safety, counter measures in defense applications, multi-colored lighting, lighting for flat panels, medical, metrology, beam projectors and other displays, high intensity lamps, spectroscopy, entertainment, theater, music, and concerts, analysis fraud detection and/or authenticating, tools, water treatment, laser dazzlers, targeting, communications, LiFi, visible light communications (VLC), sensing, detecting, distance detecting, Light Detection And Ranging (LIDAR), transformations, autonomous vehicles, transportations, leveling, curing and other chemical treatments, heating, cutting and/or ablating, pumping other optical devices, other optoelectronic devices and related applications, and source lighting and the like. Laser diodes are ideal as phosphor excitation sources. With a spatial brightness (optical intensity per unit area) greater than 10,000 times higher than conventional LEDs and the extreme directionality of the laser emission, laser diodes enable characteristics unachievable by LEDs and other light sources. Specifically, since the laser diodes output beams carrying over 1 W, over 5 W, over 10 W, or even over 100 W can be focused to very small spot sizes of less than 1 mm in diameter, less than 500 μm in diameter, less than 100 μm in diameter, or even less than 50 μm in diameter, power densities of over 1 W/mm2, 100 W/mm2, or even over 2,500 W/mm2can be achieved. When this very small and powerful beam of laser excitation light is incident on a phosphor material the ultimate point source of white light can be achieved. Assuming a phosphor conversion ratio of 200 lumens of emitted white light per optical watt of excitation light, a 5 W excitation power could generate 1000 lumens in a beam diameter of 100 μm, or 50 μm, or less. Such a point source is game changing in applications such as spotlighting or range finding where parabolic reflectors or lensing optics can be combined with the point source to create highly collimated white light spots that can travel drastically higher distances than ever possible before using LEDs or bulb technology. In some embodiments of the present invention the gallium and nitrogen containing light emitting device may not be a laser device, but instead may be configured as a superluminescent diode or superluminescent light emitting diode (SLED) device. For the purposes of this invention, a SLED device and laser diode device can be used interchangeably. A SLED is similar to a laser diode as it is based on an electrically driven junction that when injected with current becomes optically active and generates amplified spontaneous emission (ASE) and gain over a wide range of wavelengths. When the optical output becomes dominated by ASE there is a knee in the light output versus current (LI) characteristic wherein the unit of light output becomes drastically larger per unit of injected current. This knee in the LI curve resembles the threshold of a laser diode, but is much softer. The advantage of a SLED device is that SLED it can combine the unique properties of high optical emission power and extremely high spatial brightness of laser diodes that make them ideal for highly efficient long throw illumination and high brightness phosphor excitation applications with a broad spectral width of (>5 nm) that provides for an improved eye safety and image quality in some cases. The broad spectral width results in a low coherence length similar to an LED. The low coherence length provides for an improved safety such has improved eye safety. Moreover, the broad spectral width can drastically reduce optical distortions in display or illumination applications. As an example, the well-known distortion pattern referred to as “speckle” is the result of an intensity pattern produced by the mutual interference of a set of wavefronts on a surface or in a viewing plane. The general equations typically used to quantify the degree of speckle are inversely proportional to the spectral width. In the present specification, both a laser diode (LD) device and a superluminescent light emitting diode (SLED) device are sometime simply referred to “laser device”. A gallium and nitrogen containing laser diode (LD) or super luminescent light emitting diode (SLED) may comprise at least a gallium and nitrogen containing device having an active region and a cavity member and are characterized by emitted spectra generated by the stimulated emission of photons. In some embodiments a laser device emitting red laser light, i.e. light with wavelength between about 600 nm to 750 nm, are provided. These red laser diodes may comprise at least a gallium phosphorus and arsenic containing device having an active region and a cavity member and are characterized by emitted spectra generated by the stimulated emission of photons. The ideal wavelength for a red device for display applications is ˜635 nm, for green ˜530 nm and for blue 440-470 nm. There may be tradeoffs between what colors are rendered with a display using different wavelength lasers and also how bright the display is as the eye is more sensitive to some wavelengths than to others. In some embodiments according to the present invention, multiple laser diode sources are configured to excite the same phosphor or phosphor network. Combining multiple laser sources can offer many potential benefits according to this invention. First, the excitation power can be increased by beam combining to provide a more powerful excitation spit and hence produce a brighter light source. In some embodiments, separate individual laser chips are configured within the laser-phosphor light source. By including multiple lasers emitting 1 W, 2 W, 3 W, 4 W, 5 W or more power each, the excitation power can be increased and hence the source brightness would be increased. For example, by including two 3 W lasers exciting the same phosphor area, the excitation power can be increased to 6 W for double the white light brightness. In an example where about 200 lumens of white are generated per 1 watt of laser excitation power, the white light output would be increased from 600 lumens to 1200 lumens. Beyond scaling the power of each single laser diode emitter, the total luminous flux of the white light source can be increased by continuing to increase the total number of laser diodes, which can range from 10s, to 100s, and even to 1000s of laser diode emitters resulting in 10s to 100s of kW of laser diode excitation power. Scaling the number of laser diode emitters can be accomplished in many ways such as including multiple lasers in a co-package, spatial beam combining through conventional refractive optics or polarization combining, and others. Moreover, laser diode bars or arrays, and mini-bars can be utilized where each laser chip includes many adjacent laser diode emitters. For example, a bar could include from 2 to 100 laser diode emitters spaced from about 10 microns to about 400 microns apart. Similarly, the reliability of the source can be increased by using multiple sources at lower drive conditions to achieve the same excitation power as a single source driven at more harsh conditions such as higher current and voltage. In a specific area of light source application is automobile headlamp. Semiconductor based light emitting diode (LED) headlight sources were fielded in 2004, the first solid-state sources. These featured high efficiency, reliability, and compactness, but the limited light output per device and brightness caused the optics and heat sinks to be still are quite large, and the elevated temperature requirements in auto applications were challenging. Color uniformity from the blue LED excited yellow phosphor needed managed with special reflector design. Single LED failure meant the entire headlamp needed to be scrapped, resulting in challenging costs for maintenance, repair, and warranty. Moreover, the LED components are based on spontaneous emission, and therefore are not conducive to high-speed modulation required for advanced applications such as 3D sensing (LiDAR), or optical communication (LiFi). The low luminance also creates challenges for spatially dynamic automotive lighting systems that utilize spatial modulators such as MEMS or liquid crystal devices. Semiconductor laser diode (LD) based headlights started production in 2014 based on laser pumped phosphor architectures, since direct emitting lasers such as R-G-B lasers are not safe to deploy onto the road and since R-G-B sources leave gaps in the spectrum that would leave common roadside targets such as yellow or orange with insufficient reflection back to the eye. Laser pumped phosphor are solid state light sources and therefore featured the same benefits of LEDs, but with higher brightness and range from more compact headlamp reflectors. Initially, these sources exhibited high costs, reduced reliability compared to LEDs, due to being newer technology. In some cases, the laser and phosphor were combined in a single unit, and in other cases, the blue laser light was delivered by fiber to a remotely disposed phosphor module to produce white light emission. Special precautions were needed to ensure safe white light emission occurred with passive and active safety measures. Color uniformity from the blue laser excited yellow phosphor needed managed with special reflector design. In some embodiments, the invention described herein can be applied to a fiber delivered headlight comprised of one or more gallium and nitrogen containing visible laser diode for emitting laser light that is efficiently coupled into a waveguide (such as an optical fiber) to deliver the laser emission to a remote phosphor member configured on the other end of the optical fiber. The laser emission serves to excite the phosphor member and generate a high brightness white light. In a headlight application, the phosphor member and white light generation occurs in a final headlight module, from where the light is collimated and shaped onto the road to achieve the desired light pattern. This disclosure utilizes fiber delivery of visible laser light from a gallium and nitrogen containing laser diode to a remote phosphor member to generate a white light emission with high luminance, and has several key benefits over other approaches. One advantage lies in production of controllable light output or amount of light for low beam or high beam using modular design in a miniature headlight module footprint. Another advantage is to provide high luminance and long range of visibility. For example, based on recent driving speeds and safe stopping distances, a range of 800 meters to 1 km is possible from a 200 lumens on the road using a size<35 mm optic structure with light sources that are 1000 cd per mm2. Using higher luminance light sources allows one to achieve longer-range visibility for the same optics size. Further advantage of the fiber-delivered white-light headlight is able to provide high contrast. It is important to minimize glare and maximize safety and visibility for drivers and others including oncoming traffic, pedestrians, animals, and drivers headed in the same direction traffic ahead. High luminance is required to produce sharp light gradients and the specific regulated light patterns for automotive lighting. Moreover, using a waveguide such as an optical fiber, extremely sharp light gradients and ultra-safe glare reduction can be generated by reshaping and projecting the decisive light cutoff that exists from core to cladding in the light emission profile. Another advantage of the present invention is to provide rich spectrum white color light. Laser pumped phosphors are broadband solid-state light sources and therefore featured the same benefits of LEDs, but with higher luminance. Direct emitting lasers such as R-G-B lasers are not safe to deploy onto the road since R-G-B sources leave gaps in the spectrum that would leave common roadside targets such as yellow or orange with insufficient reflection back to the eye. Also, because of the remote nature of the light sources, the headlight module can be mounted onto a pre-existing heat sink with adequate thermal mass that is located anywhere in the vehicle, eliminating the need for heat sink in the headlight. One big advantage is small form factor of the light source and a low-cost solution for swiveling the light for glare mitigation and enhancing aerodynamic performance. For example, miniature optics <1 cm in diameter in a headlight module can be utilized to capture nearly 100% of the light from the fiber. The white light can be collimated and shaped with tiny diffusers or simple optical elements to produce the desired beam pattern on the road. it is desired to have extremely small optics sizes for styling of the vehicle. Using higher luminance light sources allows one to achieve smaller optics sizes for the same range of visibility. This headlight design allows one to integrate the headlight module into the grill, onto wheel cover, into seams between the hood and front bumper, etc. This headlight design features a headlight module that is extremely low mass and lightweight, and therefore minimized weight in the front of the car, contributing to safety, fuel economy, and speed/acceleration performance. For electric vehicles, this translates to increased vehicle range. Moreover, the decoupled fiber delivered architecture use pre-existing heat sink thermal mass already in vehicle, further minimizing the weight in the car. Furthermore, this headlight module is based on solid-state light source, and has long lifetime >10,000 hours. Redundancy and interchangeability are straightforward by simply replacing the fiber-delivered laser light source. Because of the fiber configuration in the design of the fiber-delivered laser-induced white light headlight module, reliability is maximized by positioning the laser-induced light source away from the hot area near engine and other heat producing components. This allows the headlight module to operate at extremely high temperatures >100° C., while the laser module can operate in a cool spot with ample heat sinking. In a specific embodiment, the present invention utilizes thermally stable, military standard style, telcordia type packaging technology. The only elements exposed to the front of the car are the complexly passive headlight module, comprised tiny macro-optical elements. There is no laser directly deployed in the headlight module, only incoherent white light and a reflective phosphor architecture inside. Direct emitting lasers such as R-G-B lasers are not safe to deploy onto the road at high power and are not used in this design. It is safe and cost efficient to assemble this fiber-delivered white light source into the car while manufacturing the vehicle. In LED-based headlights, if one high power LED element dies, the entire headlamp is typically scrapped. The fiber-delivered headlight design enables “plug and play” replacement of the light source, eliminating wasted action of completely scrapping headlights due to a failed component. The plug and play can occur without alignment, like replacing a battery, minimize warranty costs. This eliminates excessive replacement cost, customer wait times, dangerous driving conditions, and expensive loaner vehicles. Because of the ease of generating new light patterns, and the modular approach to lumen scaling, this fiber-delivered light source allows for changing lumens and beam pattern for any region without retooling for an entirely new headlamp. This convenient capability to change beam pattern can be achieved by changing tiny optics and or diffusers instead of retooling for new large reflectors. Moreover, the fiber-delivered white light source can be used in interior lights and daytime running lights (DRL), with transport or side emitting plastic optical fiber (POF). Spatially dynamic beam shaping devices such as digital-light processing (DLP), liquid-crystal display (LCD), 1 or 2 MEMS or Galvo mirror systems, lightweight swivels, scanning fiber tips. Future spatially dynamic sources may require even brighter light, such as 5000-10000 lumens from the source, to produce high definition spatial light modulation on the road using MEMS or liquid crystal components. Such dynamic lighting systems are incredibly bulky and expensive when co-locating the light source, electronics, heat sink, optics, and light modulators, and secondary optics. Therefore, they require-fiber delivered high luminance white light to enable spatial light modulation in a compact and more cost effective manner. A additional advantage of combining the emission from multiple laser diode emitters is the potential for a more circular spot by rotating the first free space diverging elliptical laser beam by 90 degrees relative to the second free space diverging elliptical laser beam and overlapping the centered ellipses on the phosphor. Alternatively, a more circular spot can be achieved by rotating the first free space diverging elliptical laser beam by 180 degrees relative to the second free space diverging elliptical laser beam and off-centered overlapping the ellipses on the phosphor to increase spot diameter in slow axis diverging direction. In another configuration, more than 2 lasers are included and some combination of the above described beam shaping spot geometry shaping is achieved. A third and important advantage is that multiple color lasers in an emitting device can significantly improve color quality (CRI and CQS) by improving the fill of the spectra in the violet/blue and cyan region of the visible spectrum. For example, two or more blue excitation lasers with slightly detuned wavelengths (e.g. 5 nm, 10 nm, 15 nm, etc.) can be included to excite a yellow phosphor and create a larger blue spectrum. As used herein, the term GaN substrate is associated with Group III-nitride based materials including GaN, InGaN, AlGaN, or other Group III containing alloys or compositions that are used as starting materials. Such starting materials include polar GaN substrates (i.e., substrate where the largest area surface is nominally an (h k l) plane wherein h=k=0, and 1 is non-zero), non-polar GaN substrates (i.e., substrate material where the largest area surface is oriented at an angle ranging from about 80-100 degrees from the polar orientation described above towards an (h k l) plane wherein l=0, and at least one of h and k is non-zero) or semi-polar GaN substrates (i.e., substrate material where the largest area surface is oriented at an angle ranging from about +0.1 to 80 degrees or 110-179.9 degrees from the polar orientation described above towards an (h k l) plane wherein l=0, and at least one of h and k is non-zero). Of course, there can be other variations, modifications, and alternatives. The laser diode device can be fabricated on a conventional orientation of a gallium and nitrogen containing film or substrate (e.g., GaN) such as the polar c-plane, on a nonpolar orientation such as the m-plane, or on a semipolar orientation such as the {30-31}, {20-21}, {30-32}, {11-22}, {10-11}, {30-3-1}, {20-2-1}, {30-3-2}, or offcuts of any of these polar, nonpolar, and semipolar planes within +/−10 degrees towards a c-plane, and/or +/−10 degrees towards an a-plane, and/or +/−10 degrees towards an m-plane. In some embodiments, a gallium and nitrogen containing laser diode laser diode comprises a gallium and nitrogen containing substrate. The substrate member may have a surface region on the polar {0001} plane (c-plane), nonpolar plane (m-plane, a-plane), and semipolar plain ({11-22}, {10-1-1}, {20-21}, {30-31}) or other planes of a gallium and nitrogen containing substrate. The laser device can be configured to emit a laser beam characterized by one or more wavelengths from about 390 nm to about 540 nm. FIG.3is a simplified schematic diagram of a laser diode formed on a gallium and nitrogen containing substrate with the cavity aligned in a direction ended with cleaved or etched mirrors according to some embodiments of the present invention. In an example, the substrate surface101is a polar c-plane and the laser stripe region110is characterized by a cavity orientation substantially in an m-direction10, which is substantially normal to an a-direction20, but can be others such as cavity alignment substantially in the a-direction. The laser strip region110has a first end107and a second end109and is formed on an m-direction on a {0001} gallium and nitrogen containing substrate having a pair of cleaved or etched mirror structures, which face each other. In another example, the substrate surface101is a semipolar plane and the laser stripe region110is characterized by a cavity orientation substantially in a projection of a c-direction10, which is substantially normal to an a-direction20, but can be others such as cavity alignment substantially in the a-direction. The laser strip region110has a first end107and a second end109and is formed on an semipolar substrate such as a {40-41}, {30-31}, {20-21}, {40-4-1}, {30-3-1}, {20-2-1}, {20-21}, or an offcut of these planes within +/−5 degrees from the c-plane and a-plane gallium and nitrogen containing substrate. Optionally, the gallium nitride substrate member is a bulk GaN substrate characterized by having a nonpolar or semipolar crystalline surface region, but can be others. The bulk GaN substrate may have a surface dislocation density below 105cm−2or 105to 107cm−2. The nitride crystal or wafer may comprise AlxInyGa1-x-yN, where 0≤x, y, x+y≤1. In one specific embodiment, the nitride crystal comprises GaN. In some embodiments, the GaN substrate has threading dislocations, at a concentration between about 105cm−2and about 108cm−2, in a direction that is substantially orthogonal or oblique with respect to the surface. The exemplary laser diode devices inFIG.3have a pair of cleaved or etched mirror structures109and107, which face each other. The first cleaved or etched facet109comprises a reflective coating and the second cleaved or etched facet107comprises no coating, an antireflective coating, or exposes gallium and nitrogen containing material. The first cleaved or etched facet109is substantially parallel with the second cleaved or etched facet107. The first and second cleaved facets109and107are provided by a scribing and breaking process according to an embodiment or alternatively by etching techniques using etching technologies such as reactive ion etching (ME), inductively coupled plasma etching (ICP), or chemical assisted ion beam etching (CAIBE), or other method. The reflective coating is selected from silicon dioxide, hafnia, and titania, tantalum pentoxide, zirconia, aluminum oxide, aluminum nitride, and aluminum oxynitride including combinations, and the like. Depending upon the design, the mirror surfaces can also comprise an anti-reflective coating. In a specific embodiment, the method of facet formation includes subjecting the substrates to a laser for pattern formation. In a preferred embodiment, the pattern is configured for the formation of a pair of facets for a ridge laser. In a preferred embodiment, the pair of facets face each other and are in parallel alignment with each other. In a preferred embodiment, the method uses a UV (355 nm) laser to scribe the laser bars. In a specific embodiment, the laser is configured on a system, which allows for accurate scribe lines configured in a different patterns and profiles. In some embodiments, the laser scribing can be performed on the back-side, front-side, or both depending upon the application. Of course, there can be other variations, modifications, and alternatives. In a specific embodiment, the method uses backside laser scribing or the like. With backside laser scribing, the method preferably forms a continuous line laser scribe that is perpendicular to the laser bars on the backside of the GaN substrate. In a specific embodiment, the laser scribe is generally about 15-20 μm deep or other suitable depth. Preferably, backside scribing can be advantageous. That is, the laser scribe process does not depend on the pitch of the laser bars or other like pattern. Accordingly, backside laser scribing can lead to a higher density of laser bars on each substrate according to a preferred embodiment. In a specific embodiment, backside laser scribing, however, may lead to residue from the tape on the facets. In a specific embodiment, backside laser scribe often requires that the substrates face down on the tape. With front-side laser scribing, the backside of the substrate is in contact with the tape. Of course, there can be other variations, modifications, and alternatives. It is well known that etch techniques such as chemical assisted ion beam etching (CAIBE), inductively coupled plasma (ICP) etching, or reactive ion etching (RIE) can result in smooth and vertical etched sidewall regions, which could serve as facets in etched facet laser diodes. In the etched facet process a masking layer is deposited and patterned on the surface of the wafer. The etch mask layer could be comprised of dielectrics such as silicon dioxide (SiO2), silicon nitride (SixNy), a combination thereof or other dielectric materials. Further, the mask layer could be comprised of metal layers such as Ni or Cr, but could be comprised of metal combination stacks or stacks comprising metal and dielectrics. In another approach, photoresist masks can be used either alone or in combination with dielectrics and/or metals. The etch mask layer is patterned using conventional photolithography and etch steps. The alignment lithography could be performed with a contact aligner or stepper aligner. Such lithographically defined mirrors provide a high level of control to the design engineer. After patterning of the photoresist mask on top of the etch mask is complete, the patterns in then transferred to the etch mask using a wet etch or dry etch technique. Finally, the facet pattern is then etched into the wafer using a dry etching technique selected from CAIBE, ICP, RIE and/or other techniques. The etched facet surfaces must be highly vertical of between about 87 and about 93 degrees or between about 89 and about 91 degrees from the surface plane of the wafer. The etched facet surface region must be very smooth with root mean square roughness values of less than about 50 nm, 20 nm, 5 nm, or 1 nm. Lastly, the etched must be substantially free from damage, which could act as nonradiative recombination centers and hence reduce the catastrophic optical mirror damage (COMD) threshold. CAIBE is known to provide very smooth and low damage sidewalls due to the chemical nature of the etch, while it can provide highly vertical etches due to the ability to tilt the wafer stage to compensate for any inherent angle in etch. The laser stripe110is characterized by a length and width. The length ranges from about 50 μm to about 3000 μm, but is preferably between about 10 μm and about 400 μm, between about 400 μm and about 800 μm, or about 800 μm and about 1600 μm, but could be others. The stripe also has a width ranging from about 0.5 μm to about 50 μm, but is preferably between about 0.8 μm and about 2.5 μm for single lateral mode operation or between about 2.5 μm and about 50 μm for multi-lateral mode operation, but can be other dimensions. In a specific embodiment, the present device has a width ranging from about 0.5 μm to about 1.5 μm, a width ranging from about 1.5 μm to about 3.0 μm, a width ranging from about 3.0 μm to about 50 μm, and others. In a specific embodiment, the width is substantially constant in dimension, although there may be slight variations. The width and length are often formed using a masking and etching process, which are commonly used in the art. The laser stripe region110is provided by an etching process selected from dry etching or wet etching. The device also has an overlying dielectric region, which exposes a p-type contact region. Overlying the contact region is a contact material, which may be metal or a conductive oxide or a combination thereof. The p-type electrical contact may be deposited by thermal evaporation, electron beam evaporation, electroplating, sputtering, or another suitable technique. Overlying the polished region of the substrate is a second contact material, which may be metal or a conductive oxide or a combination thereof and which comprises the n-type electrical contact. The n-type electrical contact may be deposited by thermal evaporation, electron beam evaporation, electroplating, sputtering, or another suitable technique. In a specific embodiment, the laser device may emit red light with a center wavelength between 600 nm and 750 nm. Such a device may comprise layers of varying compositions of AlxInyGa1-x-yAszP1-z, where x+y≤1 and z≤1. The red laser device comprises at least an n-type and p-type cladding layer, an n-type SCH of higher refractive index than the n-type cladding, a p-type SCH of higher refractive index than the p-type cladding and an active region where light is emitted. In a specific embodiment, the laser stripe is provided by an etching process selected from dry etching or wet etching. In a preferred embodiment, the etching process is dry, but can be others. The device also has an overlying dielectric region, which exposes the contact region. In a specific embodiment, the dielectric region is an oxide such as silicon dioxide, but can be others. Of course, there can be other variations, modifications, and alternatives. The laser stripe is characterized by a length and width. The length ranges from about 50 μm to about 3000 μm, but is preferably between 10 μm and 400 μm, between about 400 μm and 800 μm, or about 800 μm and 1600 μm, but could be others such as greater than 1600 μm. The stripe also has a width ranging from about 0.5 μm to about 80 μm, but is preferably between 0.8 μm and 2.5 μm for single lateral mode operation or between 2.5 μm and 60 μm for multi-lateral mode operation, but can be other dimensions. The laser strip region has a first end and a second end having a pair of cleaved or etched mirror structures, which face each other. The first facet comprises a reflective coating and the second facet comprises no coating, an antireflective coating, or exposes gallium and nitrogen containing material. The first facet is substantially parallel with the second cleaved or etched facet. Given the high gallium and nitrogen containing substrate costs, difficulty in scaling up gallium and nitrogen containing substrate size, the inefficiencies inherent in the processing of small wafers, and potential supply limitations it becomes extremely desirable to maximize utilization of available gallium and nitrogen containing substrate and overlying epitaxial material. In the fabrication of lateral cavity laser diodes, it is typically the case that minimum die size is determined by device components such as the wire bonding pads or mechanical handling considerations, rather than by laser cavity widths. Minimizing die size is critical to reducing manufacturing costs as smaller die sizes allow a greater number of devices to be fabricated on a single wafer in a single processing run. The current invention is a method of maximizing the number of devices which can be fabricated from a given gallium and nitrogen containing substrate and overlying epitaxial material by spreading out the epitaxial material onto a carrier wafer via a die expansion process. Similar to an edge emitting laser diode, a SLED is typically configured as an edge-emitting device wherein the high brightness, highly directional optical emission exits a waveguide directed outward from the side of the semiconductor chip. SLEDs are designed to have high single pass gain or amplification for the spontaneous emission generated along the waveguide. However, unlike laser diodes, they are designed to provide insufficient feedback to in the cavity to achieve the lasing condition where the gain equals the total losses in the waveguide cavity. In a typical example, at least one of the waveguide ends or facets is designed to provide very low reflectivity back into the waveguide. Several methods can be used to achieve reduced reflectivity on the waveguide end or facet. In one approach an optical coating is applied to at least one of the facets, wherein the optical coating is designed for low reflectivity such as less than 1%, less than 0.1%, less than 0.001%, or less than 0.0001% reflectivity. In another approach for reduced reflectivity the waveguide ends are designed to be tilted or angled with respect to the direction of light propagation such that the light that is reflected back into the chip does not constructively interfere with the light in the cavity to provide feedback. The tilt angle must be carefully designed around a null in the reflectivity versus angle relationship for optimum performance. The tilted or angled facet approach can be achieved in a number of ways including providing an etched facet that is designed with an optimized angle lateral angle with respect to the direction of light propagation. The angle of the tilt is pre-determined by the lithographically defined etched facet patter. Alternatively, the angled output could be achieved by curving and/or angling the waveguide with respect to a cleaved facet that forms on a pre-determined crystallographic plane in the semiconductor chip. Another approach to reduce the reflectivity is to provide a roughened or patterned surface on the facet to reduce the feedback to the cavity. The roughening could be achieved using chemical etching and/or a dry etching, or with an alternative technique. Of course, there may be other methods for reduced feedback to the cavity to form a SLED device. In many embodiments a number of techniques can be used in combination to reduce the facet reflectivity including using low reflectivity coatings in combination with angled or tilted output facets with respect to the light propagation. In a specific embodiment on a nonpolar Ga-containing substrate, the device is characterized by a spontaneously emitted light is polarized in substantially perpendicular to the c-direction. In a preferred embodiment, the spontaneously emitted light is characterized by a polarization ratio of greater than 0.1 to about 1 perpendicular to the c-direction. In a preferred embodiment, the spontaneously emitted light characterized by a wavelength ranging from about 430 nanometers to about 470 nm to yield a blue emission, or about 500 nanometers to about 540 nanometers to yield a green emission, and others. For example, the spontaneously emitted light can be violet (e.g., 395 to 420 nanometers), blue (e.g., 420 to 470 nm); green (e.g., 500 to 540 nm), or others. In a preferred embodiment, the spontaneously emitted light is highly polarized and is characterized by a polarization ratio of greater than 0.4. In another specific embodiment on a semipolar {20-21} Ga-containing substrate, the device is also characterized by a spontaneously emitted light is polarized in substantially parallel to the a-direction or perpendicular to the cavity direction, which is oriented in the projection of the c-direction. In a specific embodiment, the present invention provides an alternative device structure capable of emitting 501 nm and greater light in a ridge laser embodiment. The device is provided with a of the following epitaxially grown elements:an n-GaN or n-AlGaN cladding layer with a thickness from 100 nm to 3000 nm with Si doping level of 5×1017cm−3to 3×1018cm−3;an n-side SCH layer comprised of InGaN with molar fraction of indium of between 2% and 15% and thickness from 20 nm to 250 nm;a single quantum well or a multiple quantum well active region comprised of at least two 2.0 nm to 8.5 nm InGaN quantum wells separated by 1.5 nm and greater, and optionally up to about 12 nm, GaN or InGaN barriers;a p-side SCH layer comprised of InGaN with molar a fraction of indium of between 1% and 10% and a thickness from 15 nm to 250 nm or an upper GaN-guide layer;an electron blocking layer comprised of AlGaN with molar fraction of aluminum of between 0% and 22% and thickness from 5 nm to 20 nm and doped with Mg;a p-GaN or p-AlGaN cladding layer with a thickness from 400 nm to 1500 nm with Mg doping level of 2×1017cm−3to 2×1019cm-3; anda p++-GaN contact layer with a thickness from 20 nm to 40 nm with Mg doping level of 1×1019cm−3to 1×1021cm−3. A gallium and nitrogen containing laser diode laser device may also include other structures, such as a surface ridge architecture, a buried heterostructure architecture, and/or a plurality of metal electrodes for selectively exciting the active region. For example, the active region may comprise first and second gallium and nitrogen containing cladding layers and an indium and gallium containing emitting layer positioned between the first and second cladding layers. A laser device may further include an n-type gallium and nitrogen containing material and an n-type cladding material overlying the n-type gallium and nitrogen containing material. In a specific embodiment, the device also has an overlying n-type gallium nitride layer, an active region, and an overlying p-type gallium nitride layer structured as a laser stripe region. Additionally, the device may also include an n-side separate confinement heterostructure (SCH), p-side guiding layer or SCH, p-AlGaN EBL, among other features. In a specific embodiment, the device also has a p++ type gallium nitride material to form a contact region. In a specific embodiment, the p++ type contact region has a suitable thickness and may range from about 10 nm 50 nm, or other thicknesses. In a specific embodiment, the doping level can be higher than the p-type cladding region and/or bulk region. In a specific embodiment, the p++ type region has doping concentration ranging from about 1019to 1021Mg/am3, and others. The p++ type region preferably causes tunneling between the semiconductor region and overlying metal contact region. In a specific embodiment, each of these regions is formed using at least an epitaxial deposition technique of metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial growth techniques suitable for GaN growth. In a specific embodiment, the epitaxial layer is a high-quality epitaxial layer overlying the n-type gallium nitride layer. In some embodiments the high-quality layer is doped, for example, with Si or O to form n-type material, with a dopant concentration between about 1016cm−3and 1020cm−3. FIG.4is a cross-sectional view of a laser device200according to some embodiments of the present disclosure. As shown, the laser device includes gallium nitride substrate203, which has an underlying n-type metal back contact region201. For example, the substrate203may be characterized by a semipolar or nonpolar orientation. The device also has an overlying n-type gallium nitride layer205, an active region207, and an overlying p-type gallium nitride layer structured as a laser stripe region209. Each of these regions is formed using at least an epitaxial deposition technique of metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial growth techniques suitable for GaN growth. The epitaxial layer is a high-quality epitaxial layer overlying the n-type gallium nitride layer. In some embodiments the high-quality layer is doped, for example, with Si or O to form n-type material, with a dopant concentration between about 1016cm−3and 1020cm−3. An n-type AlnInvGa1-u-vN layer, where 0≤u, v, u+v≤1, is deposited on the substrate. The carrier concentration may lie in the range between about 1016cm−3and 1020cm−3. The deposition may be performed using metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). For example, the bulk GaN substrate is placed on a susceptor in an MOCVD reactor. After closing, evacuating, and back-filling the reactor (or using a load lock configuration) to atmospheric pressure, the susceptor is heated to a temperature between about 1000 and about 1200 degrees Celsius in the presence of a nitrogen-containing gas. The susceptor is heated to approximately 900 to 1200 degrees Celsius under flowing ammonia. A flow of a gallium-containing metalorganic precursor, such as trimethylgallium (TMG) or triethylgallium (TEG) is initiated, in a carrier gas, at a total rate between approximately 1 and 50 standard cubic centimeters per minute (sccm). The carrier gas may comprise hydrogen, helium, nitrogen, or argon. The ratio of the flow rate of the group V precursor (ammonia) to that of the group III precursor (trimethylgallium, triethylgallium, trimethylindium, trimethylaluminum) during growth is between about 2000 and about 12000. A flow of disilane in a carrier gas, with a total flow rate of between about 0.1 sccm and 10 sccm, is initiated. In one embodiment, the laser stripe region is p-type gallium nitride layer209. The laser stripe is provided by a dry etching process, but wet etching can be used. The dry etching process is an inductively coupled process using chlorine bearing species or a reactive ion etching process using similar chemistries. The chlorine bearing species are commonly derived from chlorine gas or the like. The device also has an overlying dielectric region, which exposes a contact region213. The dielectric region is an oxide such as silicon dioxide or silicon nitride, and a contact region is coupled to an overlying metal layer215. The overlying metal layer is preferably a multilayered structure containing gold and platinum (Pt/Au), palladium and gold (Pd/Au), or nickel gold (Ni/Au), or a combination thereof. In some embodiments, barrier layers and more complex metal stacks are included. Active region207preferably includes one to ten quantum-well regions or a double heterostructure region for light emission. Following deposition of the n-type layer to achieve a desired thickness, an active layer is deposited. The quantum wells are preferably InGaN with GaN, AlGaN, InAlGaN, or InGaN barrier layers separating them. In other embodiments, the well layers and barrier layers comprise AlwInxGa1-w-xN and AlyInzGa1-y-zN, respectively, where 0≤w, x, y, z, w+x, y+z≤1, where w<u, y and/or x>v, z so that the bandgap of the well layer(s) is less than that of the barrier layer(s) and the n-type layer. The well layers and barrier layers each have a thickness between about 1 nm and about 20 nm. The composition and structure of the active layer are chosen to provide light emission at a preselected wavelength. The active layer may be left undoped (or unintentionally doped) or may be doped n-type or p-type. The active region can also include an electron blocking region, and a separate confinement heterostructure. The electron-blocking layer may comprise AlsIntGa1-s-tN, where 0≤s, t, s+t≤1, with a higher bandgap than the active layer, and may be doped p-type. In one specific embodiment, the electron blocking layer includes AlGaN. In another embodiment, the electron blocking layer includes an AlGaN/GaN super-lattice structure, comprising alternating layers of AlGaN and GaN, each with a thickness between about 0.2 nm and about 5 nm. As noted, the p-type gallium nitride or aluminum gallium nitride structure is deposited above the electron blocking layer and active layer(s). The p-type layer may be doped with Mg, to a level between about 1016cm−3and 1022cm−3, with a thickness between about 5 nm and about 1000 nm. The outermost 1-50 nm of the p-type layer may be doped more heavily than the rest of the layer, so as to enable an improved electrical contact. The device also has an overlying dielectric region, for example, silicon dioxide, which exposes the contact region213. The metal contact is made of suitable material such as silver, gold, aluminum, nickel, platinum, rhodium, palladium, chromium, or the like. The contact may be deposited by thermal evaporation, electron beam evaporation, electroplating, sputtering, or another suitable technique. In a preferred embodiment, the electrical contact serves as a p-type electrode for the optical device. In another embodiment, the electrical contact serves as an n-type electrode for the optical device. The laser devices illustrated inFIG.3andFIG.4and described above are typically suitable for low-power applications. In various embodiments, the present invention realizes high output power from a diode laser is by widening a portion of the laser cavity member from the single lateral mode regime of 1.0-3.0 μm to the multi-lateral mode range 5.0-20 μm. In some cases, laser diodes having cavities at a width of 50 μm or greater are employed. The laser stripe length, or cavity length ranges from 100 to 3000 μm and employs growth and fabrication techniques such as those described in U.S. patent application Ser. No. 12/759,273, filed Apr. 13, 2010, which is incorporated by reference herein. As an example, laser diodes are fabricated on nonpolar or semipolar gallium containing substrates, where the internal electric fields are substantially eliminated or mitigated relative to polar c-plane oriented devices. It is to be appreciated that reduction in internal fields often enables more efficient radiative recombination. Further, the heavy hole mass is expected to be lighter on nonpolar and semipolar substrates, such that better gain properties from the lasers can be achieved. Optionally,FIG.4illustrates an example cross-sectional diagram of a gallium and nitrogen based laser diode device. The epitaxial device structure is formed on top of the gallium and nitrogen containing substrate member203. The substrate member may be n-type doped with O and/or Si doping. The epitaxial structures will contain n-side layers205such as an n-type buffer layer comprised of GaN, AlGaN, AlINGaN, or InGaN and n-type cladding layers comprised of GaN, AlGaN, or AlInGaN. The n-typed layers may have thickness in the range of 0.3 μm to about 3 μm or to about 5 μm and may be doped with an n-type carrier such as Si or O to concentrations between 1×1016cm−3to 1×1019cm−3. Overlying the n-type layers is the active region and waveguide layers207. This region could contain an n-side waveguide layer or separate confinement heterostructure (SCH) such as InGaN to help with optical guiding of the mode. The InGaN layer be comprised of 1 to 15% molar fraction of InN with a thickness ranging from about 30 nm to about 250 nm and may be doped with an n-type species such as Si. Overlying the SCH layer is the light emitting regions which could be comprised of a double heterostructure or a quantum well active region. A quantum well active region could be comprised of 1 to 10 quantum wells ranging in thickness from 1 nm to 20 nm comprised of InGaN. Barrier layers comprised of GaN, InGaN, or AlGaN separate the quantum well light emitting layers. The barriers range in thickness from 1 nm to about 25 nm. Overlying the light emitting layers are optionally an AlGaN or InAlGaN electron blocking layer with 5% to about 35% AlN and optionally doped with a p-type species such as Mg. Also optional is a p-side waveguide layer or SCH such as InGaN to help with optical guiding of the mode. The InGaN layer be comprised of 1 to 15% molar fraction of InN with a thickness ranging from 30 nm to about 250 nm and may be doped with an p-type species such as Mg. Overlying the active region and optional electron blocking layer and p-side waveguide layers is a p-cladding region and a p++ contact layer. The p-type cladding region is comprised of GaN, AlGaN, AlINGaN, or a combination thereof. The thickness of the p-type cladding layers is in the range of 0.3 μm to about 2 μm and is doped with Mg to a concentration of between 1×1016cm−3to 1×1019cm−3. A ridge211is formed in the p-cladding region for lateral confinement in the waveguide using an etching process selected from a dry etching or a wet etching process. A dielectric material213such as silicon dioxide or silicon nitride or deposited on the surface region of the device and an opening is created on top of the ridge to expose a portion of the p++ GaN layer. A p-contact215is deposited on the top of the device to contact the exposed p++ contact region. The p-type contact may be comprised of a metal stack containing a of Au, Pd, Pt, Ni, Ti, or Ag and may be deposited with electron beam deposition, sputter deposition, or thermal evaporation. A n-contact201is formed to the bottom of the substrate member. The n-type contact may be comprised of a metal stack containing Au, Al, Pd, Pt, Ni, Ti, or Ag and may be deposited with electron beam deposition, sputter deposition, or thermal evaporation. In multiple embodiments according to the present invention, the device layers comprise a super-luminescent light emitting diode or SLED. In all applicable embodiments a SLED device can be interchanged with or combined with laser diode devices according to the methods and architectures described in this invention. A SLED is in many ways similar to an edge emitting laser diode; however the emitting facet of the device is designed so as to have a very low reflectivity. A SLED is similar to a laser diode as it is based on an electrically driven junction that when injected with current becomes optically active and generates amplified spontaneous emission (ASE) and gain over a wide range of wavelengths. When the optical output becomes dominated by ASE there is a knee in the light output versus current (LI) characteristic wherein the unit of light output becomes drastically larger per unit of injected current. This knee in the LI curve resembles the threshold of a laser diode, but is much softer. A SLED would have a layer structure engineered to have a light emitting layer or layers clad above and below with material of lower optical index such that a laterally guided optical mode can be formed. The SLED would also be fabricated with features providing lateral optical confinement. These lateral confinement features may consist of an etched ridge, with air, vacuum, metal or dielectric material surrounding the ridge and providing a low optical-index cladding. The lateral confinement feature may also be provided by shaping the electrical contacts such that injected current is confined to a finite region in the device. In such a “gain guided” structure, dispersion in the optical index of the light emitting layer with injected carrier density provides the optical-index contrast needed to provide lateral confinement of the optical mode. In an embodiment, the LD or SLED device is characterized by a ridge with non-uniform width. The ridge is comprised by a first section of uniform width and a second section of varying width. The first section has a length between 100 and 500 μm long, though it may be longer. The first section has a width of between 1 and 2.5 μm, with a width preferably between 1 and 1.5 μm. The second section of the ridge has a first end and a second end. The first end connects with the first section of the ridge and has the same width as the first section of the ridge. The second end of the second section of the ridge is wider than the first section of the ridge, with a width between 5 and 50 μm and more preferably with a width between 15 and 35 μm. The second section of the ridge waveguide varies in width between its first and second end smoothly. In some embodiments the second derivative of the ridge width versus length is zero such that the taper of the ridge is linear. In some embodiments, the second derivative is chosen to be positive or negative. In general, the rate of width increase is chosen such that the ridge does not expand in width significantly faster than the optical mode. In specific embodiments, the electrically injected area is patterned such that only a part of the tapered portion of the waveguide is electrically injected. In an embodiment, multiple laser dice emitting at different wavelengths are transferred to the same carrier wafer in close proximity to one another; preferably within one millimeter of each other, more preferably within about 200 micrometers of each other and most preferably within about 50 μm of each other. The laser die wavelengths are chosen to be separated in wavelength by at least twice the full width at half maximum of their spectra. For example, three dice, emitting at 440 nm, 450 nm and 460 nm, respectively, are transferred to a single carrier chip with a separation between die of less than 50 μm and die widths of less than 50 μm such that the total lateral separation, center to center, of the laser light emitted by the die is less than 200 μm. The closeness of the laser die allows for their emission to be easily coupled into the same optical train or fiber optic waveguide or projected in the far field into overlapping spots. In a sense, the lasers can be operated effectively as a single laser light source. Such a configuration offers an advantage in that each individual laser light source could be operated independently to convey information using for example frequency and phase modulation of an RF signal superimposed on DC offset. The time-averaged proportion of light from the different sources could be adjusted by adjusting the DC offset of each signal. At a receiver, the signals from the individual laser sources would be demultiplexed by use of notch filters over individual photodetectors that filter out both the phosphor derived component of the white light spectra as well as the pump light from all but one of the laser sources. Such a configuration would offer an advantage over an LED based visible light communication (VLC) source in that bandwidth would scale easily with the number of laser emitters. Of course, a similar embodiment with similar advantages could be constructed from SLED emitters. After the laser diode chip fabrication as described above, the laser diode can be mounted to a submount. In some examples the submount is comprised of AlN, SiC, BeO, diamond, or other materials such as metals, ceramics, or composites. Alternatively, the submount can be an intermediate submount intended to be mounted to the common support member wherein the phosphor material is attached. The submount member may be characterized by a width, length, and thickness. In an example wherein the submount is the common support member for the phosphor and the laser diode chip the submount would have a width and length ranging in dimension from about 0.5 mm to about 5 mm or to about 15 mm and a thickness ranging from about 150 μm to about 2 mm. In the example wherein the submount is an intermediate submount between the laser diode chip and the common support member it could be characterized by width and length ranging in dimension from about 0.5 mm to about 5 mm and the thickness may range from about 50 μm to about 500 μm. The laser diode is attached to the submount using a bonding process, a soldering process, a gluing process, or a combination thereof. In one embodiment the submount is electrically isolating and has metal bond pads deposited on top. The laser chip is mounted to at least one of those metal pads. The laser chip can be mounted in a p-side down or a p-side up configuration. After bonding the laser chip, wire bonds are formed from the chip to the submount such that the final chip on submount (CoS) is completed and ready for integration. A schematic diagram illustrating a CoS based on a conventional laser diode formed on gallium and nitrogen containing substrate technology according to this present invention is shown inFIG.5. The CoS is comprised of submount material301configured to act as an intermediate material between a laser diode chip302and a final mounting surface. The submount is configured with electrodes303and305that may be formed with deposited metal layers such as Au. In one example, Ti/Pt/Au is used for the electrodes. Wirebonds304are configured to couple the electrical power from the electrodes303and305on the submount to the laser diode chip to generate a laser beam output306from the laser diode. The electrodes303and305are configured for an electrical connection to an external power source such as a laser driver, a current source, or a voltage source. Wirebonds304can be formed on the electrodes to couple electrical power to the laser diode device and activate the laser. In another embodiment, the gallium and nitrogen containing laser diode fabrication includes an epitaxial release step to lift off the epitaxially grown gallium and nitrogen layers and prepare them for transferring to a carrier wafer which could comprise the submount after laser fabrication. The transfer step requires precise placement of the epitaxial layers on the carrier wafer to enable subsequent processing of the epitaxial layers into laser diode devices. The attachment process to the carrier wafer could include a wafer bonding step with a bond interface comprised of metal-metal, semiconductor-semiconductor, glass-glass, dielectric-dielectric, or a combination thereof. In this embodiment, gallium and nitrogen containing epitaxial layers are grown on a bulk gallium and nitrogen containing substrate. The epitaxial layer stack comprises at least a sacrificial release layer and the laser diode device layers overlying the release layers. Following the growth of the epitaxial layers on the bulk gallium and nitrogen containing substrate, the semiconductor device layers are separated from the substrate by a selective wet etching process such as a PEC etch configured to selectively remove the sacrificial layers and enable release of the device layers to a carrier wafer. In one embodiment, a bonding material is deposited on the surface overlying the semiconductor device layers. A bonding material is also deposited either as a blanket coating or patterned on the carrier wafer. Standard lithographic processes are used to selectively mask the semiconductor device layers. The wafer is then subjected to an etch process such as dry etch or wet etch processes to define via structures that expose the sacrificial layers on the sidewall of the mesa structure. As used herein, the term mesa region or mesa is used to describe the patterned epitaxial material on the gallium and nitrogen containing substrate and prepared for transferring to the carrier wafer. The mesa region can be any shape or form including a rectangular shape, a square shape, a triangular shape, a circular shape, an elliptical shape, a polyhedron shape, or other shape. The term mesa shall not limit the scope of the present invention. Following the definition of the mesa, a selective etch process is performed to fully or partially remove the sacrificial layers while leaving the semiconductor device layers intact. The resulting structure comprises undercut mesas comprised of epitaxial device layers. The undercut mesas correspond to dice from which semiconductor devices will be formed on. In some embodiments a protective passivation layer can be employed on the sidewall of the mesa regions to prevent the device layers from being exposed to the selective etch when the etch selectivity is not perfect. In other embodiments a protective passivation is not needed because the device layers are not sensitive to the selective etch or measures are taken to prevent etching of sensitive layers such as shorting the anode and cathode. The undercut mesas corresponding to device dice are then transferred to the carrier wafer using a bonding technique wherein the bonding material overlying the semiconductor device layers is joined with the bonding material on the carrier wafer. The resulting structure is a carrier wafer comprising gallium and nitrogen containing epitaxial device layers overlying the bonding region. In a preferred embodiment PEC etching is deployed as the selective etch to remove the sacrificial layers. PEC is a photo-assisted wet etch technique that can be used to etch GaN and its alloys. The process involves an above-band-gap excitation source and an electrochemical cell formed by the semiconductor and the electrolyte solution. In this case, the exposed (Al,In,Ga)N material surface acts as the anode, while a metal pad deposited on the semiconductor acts as the cathode. The above-band-gap light source generates electron-hole pairs in the semiconductor. Electrons are extracted from the semiconductor via the cathode while holes diffuse to the surface of material to form an oxide. Since the diffusion of holes to the surface requires the band bending at the surface to favor a collection of holes, PEC etching typically works only for n-type material although some methods have been developed for etching p-type material. The oxide is then dissolved by the electrolyte resulting in wet etching of the semiconductor. Different types of electrolyte including HCl, KOH, and HNO3have been shown to be effective in PEC etching of GaN and its alloys. The etch selectivity and etch rate can be optimized by selecting a favorable electrolyte. It is also possible to generate an external bias between the semiconductor and the cathode to assist with the PEC etching process. In a preferred embodiment, a semiconductor device epitaxy material with the underlying sacrificial region is fabricated into a dense array of mesas on the gallium and nitrogen containing bulk substrate with the overlying semiconductor device layers. The mesas are formed using a patterning and a wet or dry etching process wherein the patterning comprises a lithography step to define the size and pitch of the mesa regions. Dry etching techniques such as reactive ion etching, inductively coupled plasma etching, or chemical assisted ion beam etching are candidate methods. Alternatively, a wet etch can be used. The etch is configured to terminate at or below a sacrificial region below the device layers. This is followed by a selective etch process such as PEC to fully or partially etch the exposed sacrificial region such that the mesas are undercut. This undercut mesa pattern pitch will be referred to as the ‘first pitch’. The first pitch is often a design width that is suitable for fabricating each of the epitaxial regions on the substrate, while not large enough for the desired completed semiconductor device design, which often desire larger non-active regions or regions for contacts and the like. For example, these mesas would have a first pitch ranging from about 5 μm to about 500 μm or to about 5000 μm. Each of these mesas is a ‘die’. In a preferred embodiment, these dice are transferred to a carrier wafer at a second pitch using a selective bonding process such that the second pitch on the carrier wafer is greater than the first pitch on the gallium and nitrogen containing substrate. In this embodiment the dice are on an expanded pitch for so called “die expansion”. In an example, the second pitch is configured with the dice to allow each die with a portion of the carrier wafer to be a semiconductor device, including contacts and other components. For example, the second pitch would be about 50 μm to about 1000 μm or to about 5000 μm, but could be as large at about 3-10 mm or greater in the case where a large semiconductor device chip is required for the application. The larger second pitch could enable easier mechanical handling without the expense of the costly gallium and nitrogen containing substrate and epitaxial material, allow the real estate for additional features to be added to the semiconductor device chip such as bond pads that do not require the costly gallium and nitrogen containing substrate and epitaxial material, and/or allow a smaller gallium and nitrogen containing epitaxial wafer containing epitaxial layers to populate a much larger carrier wafer for subsequent processing for reduced processing cost. For example, a 4 to 1 die expansion ratio would reduce the density of the gallium and nitrogen containing material by a factor of 4, and hence populate an area on the carrier wafer 4 times larger than the gallium and nitrogen containing substrate. This would be equivalent to turning a 2″ gallium and nitrogen substrate into a 4″ carrier wafer. In particular, the present invention increases utilization of substrate wafers and epitaxy material through a selective area bonding process to transfer individual die of epitaxy material to a carrier wafer in such a way that the die pitch is increased on the carrier wafer relative to the original epitaxy wafer. The arrangement of epitaxy material allows device components which do not require the presence of the expensive gallium and nitrogen containing substrate and overlying epitaxy material often fabricated on a gallium and nitrogen containing substrate to be fabricated on the lower cost carrier wafer, allowing for more efficient utilization of the gallium and nitrogen containing substrate and overlying epitaxy material. FIG.6is a schematic representation of the die expansion process with selective area bonding according to the present invention. A device wafer is prepared for bonding in accordance with an embodiment of this invention. The device wafer consists of a substrate606, buffer layers603, a fully removed sacrificial layer609, device layers602, bonding media601, cathode metal605, and an anchor material604. The sacrificial layer609is removed in the PEC etch with the anchor material604is retained. The mesa regions formed in the gallium and nitrogen containing epitaxial wafer form dice of epitaxial material and release layers defined through processing. Individual epitaxial material die are formed at first pitch. A carrier wafer is prepared consisting of the carrier wafer substrate607and bond pads608at second pitch. The substrate606is aligned to the carrier wafer607such that a subset of the mesa on the gallium and nitrogen containing substrate606with a first pitch aligns with a subset of bond pads608on the carrier wafer607at a second pitch. Since the first pitch is greater than the second pitch and the mesas will comprise device die, the basis for die expansion is established. The bonding process is carried out and upon separation of the substrate from the carrier wafer607the subset of mesas on the substrate606are selectively transferred to the carrier wafer607. The process is then repeated with a second set of mesas and bond pads608on the carrier wafer607until the carrier wafer607is populated fully by epitaxial mesas. The gallium and nitrogen containing epitaxy substrate201can now optionally be prepared for reuse. In the example depicted inFIG.6, one quarter of the epitaxial dice on the epitaxy wafer606are transferred in this first selective bond step, leaving three quarters on the epitaxy wafer606. The selective area bonding step is then repeated to transfer the second quarter, third quarter, and fourth quarter of the epitaxial die to the patterned carrier wafer607. This selective area bond may be repeated any number of times and is not limited to the four steps depicted inFIG.6. The result is an array of epitaxial die on the carrier wafer607with a wider die pitch than the original die pitch on the epitaxy wafer606. The die pitch on the epitaxial wafer606will be referred to as pitch1, and the die pitch on the carrier wafer607will be referred to as pitch2, where pitch2is greater than pitch1. In one embodiment the bonding between the carrier wafer and the gallium and nitrogen containing substrate with epitaxial layers is performed between bonding layers that have been applied to the carrier and the gallium and nitrogen containing substrate with epitaxial layers. The bonding layers can be a variety of bonding pairs including metal-metal, oxide-oxide, soldering alloys, photoresists, polymers, wax, etc. Only epitaxial dice which are in contact with a bond bad608on the carrier wafer607will bond. Sub-micron alignment tolerances are possible on commercial die bonders. The epitaxy wafer606is then pulled away, breaking the epitaxy material at a weakened epitaxial release layer609such that the desired epitaxial layers remain on the carrier wafer607. Herein, a ‘selective area bonding step’ is defined as a single iteration of this process. In one embodiment, the carrier wafer607is patterned in such a way that only selected mesas come in contact with the metallic bond pads608on the carrier wafer607. When the epitaxy substrate606is pulled away the bonded mesas break off at the weakened sacrificial region, while the un-bonded mesas remain attached to the epitaxy substrate606. This selective area bonding process can then be repeated to transfer the remaining mesas in the desired configuration. This process can be repeated through any number of iterations and is not limited to the two iterations depicted inFIG.6. The carrier wafer can be of any size, including but not limited to about 2 inch, 3 inch, 4 inch, 6 inch, 8 inch, and 12 inch. After all desired mesas have been transferred, a second bandgap selective PEC etching can be optionally used to remove any remaining sacrificial region material to yield smooth surfaces. At this point standard semiconductor device processes can be carried out on the carrier wafer. Another embodiment of the invention incorporates the fabrication of device components on the dense epitaxy wafers before the selective area bonding steps. In an example, the present invention provides a method for increasing the number of gallium and nitrogen containing semiconductor devices which can be fabricated from a given epitaxial surface area; where the gallium and nitrogen containing epitaxial layers overlay gallium and nitrogen containing substrates. The gallium and nitrogen containing epitaxial material is patterned into die with a first die pitch; the die from the gallium and nitrogen containing epitaxial material with a first pitch is transferred to a carrier wafer to form a second die pitch on the carrier wafer; the second die pitch is larger than the first die pitch. In an example, each epitaxial device die is an etched mesa with a pitch of between about 1 μm and about 100 μm wide or between about 100 μm and about 500 μm wide or between about 500 μm and about 3000 μm wide and between about 100 and about 3000 μm long. In an example, the second die pitch on the carrier wafer is between about 100 μm and about 200 μm or between about 200 μm and about 1000 μm or between about 1000 μm and about 3000 μm. In an example, the second die pitch on the carrier wafer is between about 2 times and about 50 times larger than the die pitch on the epitaxy wafer. In an example, semiconductor LED devices, laser devices, or electronic devices are fabricated on the carrier wafer after epitaxial transfer. In an example, the semiconductor devices contain GaN, AlN, InN, InGaN, AlGaN, InAlN, and/or InAlGaN. In an example, the gallium and nitrogen containing material are grown on a polar, nonpolar, or semipolar plane. In an example, one or multiple semiconductor devices are fabricated on each die of epitaxial material. In an example, device components which do not require epitaxy material are placed in the space between epitaxy die. In one embodiment, device dice are transferred to a carrier wafer such that the distance between die is expanded in both the transverse as well as lateral directions. This can be achieved by spacing bond pads on the carrier wafer with larger pitches than the spacing of device die on the substrate. In another embodiment of the invention device dice from a plurality of epitaxial wafers are transferred to the carrier wafer such that each design width on the carrier wafer contains dice from a plurality of epitaxial wafers. When transferring dice at close spacing from multiple epitaxial wafers, it is important for the un-transferred dice on the epitaxial wafer to not inadvertently contact and bond to die already transferred to the carrier wafer. To achieve this, epitaxial dice from a first epitaxial wafer are transferred to a carrier wafer using the methods described above. A second set of bond pads are then deposited on the carrier wafer and are made with a thickness such that the bonding surface of the second pads is higher than the top surface of the first set of transferred die. This is done to provide adequate clearance for bonding of the dice from the second epitaxial wafer. A second epitaxial wafer transfers a second set of dice to the carrier wafer. Finally, the semiconductor devices are fabricated, and passivation layers are deposited followed by electrical contact layers that allow each die to be individually driven. The dice transferred from the first and second substrates are spaced at a pitch which is smaller than the second pitch of the carrier wafer. This process can be extended to transfer of dice from any number of epitaxial substrates, and to transfer of any number of devices per dice from each epitaxial substrate. A schematic diagram illustrating a CoS based on lifted off and transferred epitaxial gallium and nitrogen containing layers according to this present invention is shown inFIG.7. The CoS is comprised of submount material901configured from the carrier wafer with the transferred epitaxial material with a laser diode configured within the epitaxy902. Electrodes903and904are electrically coupled to the n-side and the p-side of the laser diode device and configured to transmit power from an external source to the laser diode to generate a laser beam output905from the laser diode. The electrodes are configured for an electrical connection to an external power source such as a laser driver, a current source, or a voltage source. Wirebonds can be formed on the electrodes to couple the power to the laser diode device. This integrated CoS device with transferred epitaxial material offers advantages over the conventional configuration such as size, cost, and performance due to the low thermal impedance. Further process and device description for this embodiment describing laser diodes formed in gallium and nitrogen containing epitaxial layers that have been transferred from the native gallium and nitrogen containing substrates are described in U.S. patent application Ser. No. 14/312,427 and U.S. Patent Publication No. 2015/0140710, which are incorporated by reference herein. As an example, this technology of GaN transfer can enable lower cost, higher performance, and a more highly manufacturable process flow. Phosphor selection is a key consideration within the laser based integrated white light source. The phosphor must be able to withstand the extreme optical intensity and associated heating induced by the laser excitation spot without severe degradation. Important characteristics to consider for phosphor selection include:A high conversion efficiency of optical excitation power to white light lumens. In the example of a blue laser diode exciting a yellow phosphor, a conversion efficiency of over 150 lumens per optical watt, or over 200 lumens per optical watt, or over 300 lumens per optical watt is desired.A high optical damage threshold capable of withstanding 1-20 W of laser power in a spot comprising a diameter of 1 mm, 500 μm, 200 μm, 100 μm, or even 50 μm.High thermal damage threshold capable of withstanding temperatures of over 150° C., over 200° C., or over 300° C. without decomposition.A low thermal quenching characteristic such that the phosphor remains efficient as it reaches temperatures of over 150° C., 200° C., or 250° C.A high thermal conductivity to dissipate the heat and regulate the temperature. Thermal conductivities of greater than 3 W/m-K, greater than 5 W/m-K, greater than 10 W/m-K, and even greater than 15 W/m-K are desirable.A proper phosphor emission color for the application.A suitable porosity characteristic that leads to the desired scattering of the coherent excitation without unacceptable reduction in thermal conductivity or optical efficiency.A proper form factor for the application. Such form factors include, but are not limited to blocks, plates, disks, spheres, cylinders, rods, or a similar geometrical element. Proper choice will be dependent on whether phosphor is operated in transmissive or reflective mode and on the absorption length of the excitation light in the phosphor.A surface condition optimized for the application. In an example, the phosphor surfaces can be intentionally roughened for improved light extraction. In a preferred embodiment, a blue laser diode operating in the 420 nm to 480 nm wavelength range would be combined with a phosphor material providing a yellowish emission in the 560 nm to 580 nm range such that when mixed with the blue emission of the laser diode a white light is produced. For example, to meet a white color point on the black body line the energy of the combined spectrum may be comprised of about 30% from the blue laser emission and about 70% from the yellow phosphor emission. In other embodiments phosphors with red, green, yellow, and even blue emission can be used in combination with the laser diode excitation sources in the violet, ultra-violet, or blue wavelength range to produce a white light with color mixing. Although such white light systems may be more complicated due to the use of more than one phosphor member, advantages such as improved color rendering could be achieved. In an example, the light emitted from the laser diodes is partially converted by the phosphor element. In an example, the partially converted light emitted generated in the phosphor element results in a color point, which is white in appearance. In an example, the color point of the white light is located on the Planckian blackbody locus of points. In an example, the color point of the white light is located within du′v′ of less than 0.010 of the Planckian blackbody locus of points. In an example, the color point of the white light is preferably located within du′v′ of less than 0.03 of the Planckian blackbody locus of points. The phosphor material can be operated in a transmissive mode, a reflective mode, or a combination of a transmissive mode and reflective mode, or other modes. The phosphor material is characterized by a conversion efficiency, a resistance to thermal damage, a resistance to optical damage, a thermal quenching characteristic, a porosity to scatter excitation light, and a thermal conductivity. In a preferred embodiment the phosphor material is comprised of a yellow emitting YAG material doped with Ce with a conversion efficiency of greater than 100 lumens per optical watt, greater than 200 lumens per optical watt, or greater than 300 lumens per optical watt, and can be a polycrystalline ceramic material or a single crystal material. In some embodiments of the present invention, the environment of the phosphor can be independently tailored to result in high efficiency with little or no added cost. Phosphor optimization for laser diode excitation can include high transparency, scattering or non-scattering characteristics, and use of ceramic phosphor plates. Decreased temperature sensitivity can be determined by doping levels. A reflector can be added to the backside of a ceramic phosphor, reducing loss. The phosphor can be shaped to increase in-coupling, increase out-coupling, and/or reduce back reflections. Surface roughening is a well-known means to increase extraction of light from a solid material. Coatings, mirrors, or filters can be added to the phosphors to reduce the amount of light exiting the non-primary emission surfaces, to promote more efficient light exit through the primary emission surface, and to promote more efficient in-coupling of the laser excitation light. Of course, there can be additional variations, modifications, and alternatives. In some embodiments, certain types of phosphors will be best suited in this demanding application with a laser excitation source. As an example, ceramic yttrium aluminum garnets (YAG) doped with Ce3+ions, or YAG based phosphors can be ideal candidates. They are doped with species such as Ce to achieve the proper emission color and are often comprised of a porosity characteristic to scatter the excitation source light, and nicely break up the coherence in laser excitation. As a result of its cubic crystal structure the YAG:Ce can be prepared as a highly transparent single crystal as well as a polycrystalline bulk material. The degree of transparency and the luminescence are depending on the stoichiometric composition, the content of dopant, and entire processing and sintering route. The transparency and degree of scattering centers can be optimized for a homogenous mixture of blue and yellow light. The YAG:Ce can be configured to emit a green emission. In some embodiments the YAG can be doped with Eu to emit a red emission. In a preferred embodiment according to this invention, the white light source is configured with a ceramic polycrystalline YAG:Ce phosphors comprising an optical conversion efficiency of greater than 100 lumens per optical excitation watt, of greater than 200 lumens per optical excitation watt, or even greater than 300 lumens per optical excitation watt. Additionally, the ceramic YAG:Ce phosphors is characterized by a temperature quenching characteristics above 150° C., above 200° C., or above 250° C. and a high thermal conductivity of 5-10 W/m-K to effectively dissipate heat to a heat sink member and keep the phosphor at an operable temperature. In another preferred embodiment according to this invention, the white light source is configured with a single crystal phosphor (SCP) such as YAG:Ce. In one example the Ce:Y3Al5O12SCP can be grown by the Czochralski technique. In this embodiment according the present invention the SCP based on YAG:Ce is characterized by an optical conversion efficiency of greater than 100 lumens per optical excitation watt, of greater than 200 lumens per optical excitation watt, or even greater than 300 lumens per optical excitation watt. Additionally, the single crystal YAG:Ce phosphors is characterized by a temperature quenching characteristics above 150° C., above 200° C., or above 300° C. and a high thermal conductivity of 8-20 W/m-K to effectively dissipate heat to a heat sink member and keep the phosphor at an operable temperature. In addition to the high thermal conductivity, high thermal quenching threshold, and high conversion efficiency, the ability to shape the phosphors into tiny forms that can act as ideal “point” sources when excited with a laser is an attractive feature. In some embodiments the YAG:Ce can be configured to emit a yellow emission. In alternative or the same embodiments a YAG:Ce can be configured to emit a green emission. In yet alternative or the same embodiments the YAG can be doped with Eu to emit a red emission. In some embodiments a LuAG is configured for emission. In alternative embodiments, silicon nitrides or aluminum-oxi-nitrides can be used as the crystal host materials for red, green, yellow, or blue emissions. In an alternative embodiment, a powdered single crystal or ceramic phosphor such as a yellow phosphor or green phosphor is included. The powdered phosphor can be dispensed on a transparent member for a transmissive mode operation or on a solid member with a reflective layer on the back surface of the phosphor or between the phosphor and the solid member to operate in a reflective mode. The phosphor powder may be held together in a solid structure using a binder material wherein the binder material is preferable in inorganic material with a high optical damage threshold and a favorable thermal conductivity. The phosphor power may be comprised of a colored phosphor and configured to emit a white light when excited by and combined with the blue laser beam or excited by a violet laser beam. The powdered phosphors could be comprised of YAG, LuAG, or other types of phosphors. In one embodiment of the present invention the phosphor material contains a yttrium aluminum garnet host material and a rare earth doping element, and others. In an example, the wavelength conversion element is a phosphor which contains a rare earth doping element, selected from a of Ce, Nd, Er, Yb, Ho, Tm, Dy and Sm, combinations thereof, and the like. In an example, the phosphor material is a high-density phosphor element. In an example, the high-density phosphor element has a density greater than 90% of pure host crystal. Cerium (III)-doped YAG (YAG:Ce3+, or Y3Al5O12:Ce3+) can be used wherein the phosphor absorbs the light from the blue laser diode and emits in a broad range from greenish to reddish, with most of output in yellow. This yellow emission combined with the remaining blue emission gives the “white” light, which can be adjusted to color temperature as warm (yellowish) or cold (bluish) white. The yellow emission of the Ce3+:YAG can be tuned by substituting the cerium with other rare earth elements such as terbium and gadolinium and can even be further adjusted by substituting some or all of the aluminum in the YAG with gallium. In alternative examples, various phosphors can be applied to this invention, which include, but are not limited to organic dyes, conjugated polymers, semiconductors such as AlInGaP or InGaN, yttrium aluminum garnets (YAGs) doped with Ce3+ions (Y1-aGda)3(Al1-bGab)5O12:Ce3+, SrGa2S4:Eu2+, SrS:Eu2+, terbium aluminum based garnets (TAGs) (Tb3Al5O5), colloidal quantum dot thin films containing CdTe, ZnS, ZnSe, ZnTe, CdSe, or CdTe. In further alternative examples, some rare-earth doped SiAlONs can serve as phosphors. Europium(II)-doped β-SiAlON absorbs in ultraviolet and visible light spectrum and emits intense broadband visible emission. Its luminance and color does not change significantly with temperature, due to the temperature-stable crystal structure. In an alternative example, green and yellow SiAlON phosphor and a red CaAlSiN3-based (CASN) phosphor may be used. In yet a further example, white light sources can be made by combining near ultraviolet emitting laser diodes with a mixture of high efficiency europium based red and blue emitting phosphors plus green emitting copper and aluminum doped zinc sulfide (ZnS:Cu,Al). In an example, a phosphor or phosphor blend can be selected from a of (Y, Gd, Tb, Sc, Lu, La)3(Al, Ga, In)5O12:Ce3+, SrGa2S4:Eu2+, SrS:Eu2+, and colloidal quantum dot thin films comprising CdTe, ZnS, ZnSe, ZnTe, CdSe, or CdTe. In an example, a phosphor is capable of emitting substantially red light, wherein the phosphor is selected from a of the group consisting of (Gd,Y,Lu,La)2O3:Eu3+, Bi3+; (Gd,Y,Lu,La)2O2S:Eu3+, Bi3+; (Gd,Y,Lu,La)VO4:Eu3+, Bi3+; Y2(O,S)3:Eu3+; Ca1-xMo1-ySiyO4: where 0.05<x<0.5, 0<y<0.1; (Li,Na,K)5Eu(W,Mo)O4; (Ca,Sr)S:Eu2+; SrY2S4:Eu2+; CaLa2S4:Ce3+; (Ca,Sr)S:Eu2+; 3.5MgO×0.5MgF2×GeO2:Mn4+(MFG); (Ba,Sr,Ca)MgxP2O7:Eu2+, Mn2+; (Y,Lu)2WO6:Eu3+, Mo6+; (Ba,Sr,Ca)3MgxSi2O8:Eu2+, Mn2+, wherein 1<x<2; (RE1-yCey)Mg2-xLixSi3-xPxO12, where RE is at least one of Sc, Lu, Gd, Y, and Tb, 0.0001<x<0.1 and 0.001<y<0.1; (Y, Gd, Lu, La)2-xEuxW1-yMoyO6, where 0.5<x<1.0, 0.01<y<1.0; (SrCa)1-xEuxSi5N8, where 0.01<x<0.3; SrZnO2:Sm+3; MmOnX, wherein M is selected from the group of Sc, Y, a lanthanide, an alkali earth metal and mixtures thereof; X is a halogen; 1<m<3; and 1<n<4, and wherein the lanthanide doping level can range from 0.1 to 40% spectral weight; and Eu3+activated phosphate or borate phosphors; and mixtures thereof. Further details of other phosphor species and related techniques can be found in U.S. Pat. No. 8,956,894, in the name of Raring et al. issued Feb. 17, 2015, and titled “White light devices using non-polar or semipolar gallium containing materials and phosphors”, which is commonly owned, and hereby incorporated by reference herein. In some embodiments of the present invention, ceramic phosphor materials are embedded in a binder material such as silicone. This configuration is typically less desirable because the binder materials often have poor thermal conductivity, and thus get very hot wherein the rapidly degrade and even burn. Such “embedded” phosphors are often used in dynamic phosphor applications such as color wheels where the spinning wheel cools the phosphor and spreads the excitation spot around the phosphor in a radial pattern. Sufficient heat dissipation from the phosphor is a critical design consideration for the integrated white light source based on laser diode excitation. Specifically, the optically pumped phosphor system has sources of loss in the phosphor that result is thermal energy and hence must be dissipated to a heat-sink for optimal performance. The two primary sources of loss are the Stokes loss which is a result of converting photons of higher energy to photons of lower energy such that difference in energy is a resulting loss of the system and is dissipated in the form of heat. Additionally, the quantum efficiency or quantum yield measuring the fraction of absorbed photons that are successfully re-emitted is not unity such that there is heat generation from other internal absorption processes related to the non-converted photons. Depending on the excitation wavelength and the converted wavelength, the Stokes loss can lead to greater than 10%, greater than 20%, and greater than 30%, and greater loss of the incident optical power to result in thermal power that must be dissipated. The quantum losses can lead to an additional 10%, greater than 20%, and greater than 30%, and greater of the incident optical power to result in thermal power that must be dissipated. With laser beam powers in the 1 W to 100 W range focused to spot sizes of less than 1 mm in diameter, less than 500 μm in diameter, or even less than 100 μm in diameter, power densities of over 1 W/mm2, 100 W/mm2, or even over 2,500 W/mm2can be generated. As an example, assuming that the spectrum is comprised of 30% of the blue pump light and 70% of the converted yellow light and a best case scenario on Stokes and quantum losses, we can compute the dissipated power density in the form of heat for a 10% total loss in the phosphor at 0.1 W/mm2, 10 W/mm2, or even over 250 W/mm2. Thus, even for this best-case scenario example, this is a tremendous amount of heat to dissipate. This heat generated within the phosphor under the high intensity laser excitation can limit the phosphor conversion performance, color quality, and lifetime. For optimal phosphor performance and lifetime, not only should the phosphor material itself have a high thermal conductivity, but it should also be attached to the submount or common support member with a high thermal conductivity joint to transmit the heat away from the phosphor and to a heat-sink. In this invention, the phosphor is attached to a remote submount member that is packaged in a separate assembly. In some embodiments, a heatsink can be used to support the phosphor for release heat generated during wavelength conversion. Ideally the phosphor bond interface will have a substantially large area with a flat surface on both the phosphor side and the support member sides of the interface. In the present invention, the laser diode output beam must be configured to be incident on the phosphor material to excite the phosphor. In some embodiments the laser beam may be directly incident on the phosphor and in other embodiments the laser beam may interact with an optic, reflector, waveguide, or other object to manipulate the beam prior to incidence on the phosphor. Examples of such optics include, but are not limited to ball lenses, aspheric collimator, aspheric lens, fast or slow axis collimators, dichroic mirrors, turning mirrors, optical isolators, but could be others. In some embodiments, the apparatus typically has a free space with a non-guided laser beam characteristic transmitting the emission of the laser beam from the laser device to the phosphor material. The laser beam spectral width, wavelength, size, shape, intensity, and polarization are configured to excite the phosphor material. The beam can be configured by positioning it at the precise distance from the phosphor to exploit the beam divergence properties of the laser diode and achieve the desired spot size. In one embodiment, the incident angle from the laser to the phosphor is optimized to achieve a desired beam shape on the phosphor. For example, due to the asymmetry of the laser aperture and the different divergent angles on the fast and slow axis of the beam the spot on the phosphor produced from a laser that is configured normal to the phosphor would be elliptical in shape, typically with the fast axis diameter being larger than the slow axis diameter. To compensate this, the laser beam incident angle on the phosphor can be optimized to stretch the beam in the slow axis direction such that the beam is more circular on phosphor. In other embodiments free space optics such as collimating lenses can be used to shape the beam prior to incidence on the phosphor. The beam can be characterized by a polarization purity of greater than 50% and less than 100%. As used herein, the term “polarization purity” means greater than 50% of the emitted electromagnetic radiation is in a substantially similar polarization state such as the transverse electric (TE) or transverse magnetic (TM) polarization states, but can have other meanings consistent with ordinary meaning. The white light apparatus also has an electrical input interface configured to couple electrical input power to the laser diode device to generate the laser beam and excite the phosphor material. In an example, the laser beam incident on the phosphor has a power of less than 0.1 W, greater than 0.1 W, greater than 0.5 W, greater than 1 W, greater than 5 W, greater than 10 W, or greater than 20 W. The white light source configured to produce greater than 1 lumen, 10 lumens, 100 lumens, 1000 lumens, 10,000 lumens, or greater of white light output. The support member is configured to transport thermal energy from the at least one laser diode device and the phosphor material to a heat sink. The support member is configured to provide thermal impedance of less than 10 degrees Celsius per watt, less than 5 degrees Celsius per watt, or less than 3 degrees Celsius per watt of dissipated power characterizing a thermal path from the laser device to a heat sink. The support member is comprised of a thermally conductive material such as copper with a thermal conductivity of about 400 W/(m-K), aluminum with a thermal conductivity of about 200 W/(mK), 4H—SiC with a thermal conductivity of about 370 W/(m-K), 6H—SiC with a thermal conductivity of about 490 W/(m-K), AlN with a thermal conductivity of about 230 W/(m-K), a synthetic diamond with a thermal conductivity of about >1000 W/(m-K), sapphire, or other metals, ceramics, or semiconductors. The support member may be formed from a growth process such as SiC, AlN, or synthetic diamond, and then mechanically shaped by machining, cutting, trimming, or molding. Alternatively, the support member may be formed from a metal such as copper, copper tungsten, aluminum, or other by machining, cutting, trimming, or molding. Currently, solid state lighting is dominated by systems utilizing blue or violet emitting light emitting diodes (LEDs) to excite phosphors which emit a broader spectrum. The combined spectrum of the so-called pump LEDs and the phosphors can be optimized to yield white light spectra with controllable color point and good color rendering index. Peak wall plug efficiencies for state of the art LEDs are quite high, above 70%, such that LED based white light bulbs are now the leading lighting technology for luminous efficacy. As laser light sources, especially high-power blue laser diodes made from gallium and nitrogen containing material based novel manufacture processes, have shown many advantageous functions on quantum efficiency, power density, modulation rate, surface brightness over conventional LEDs. This opens up the opportunity to use lighting fixtures, lighting systems, displays, projectors and the like based on solid-state light sources as a means of transmitting information with high bandwidth using visible light. It also enables utilizing the modulated laser signal or direct laser light spot manipulation to measure and or interact with the surrounding environment, transmit data to other electronic systems and respond dynamically to inputs from various sensors. Such applications are herein referred to as “smart lighting” applications. In some embodiments, the present invention provides novel uses and configurations of gallium and nitrogen containing laser diodes in communication systems such as visible light communication systems. More specifically the present invention provides communication systems related to smart lighting applications with gallium-and-nitrogen-based lasers light sources coupled to one or more sensors with a feedback loop or control circuitry to trigger the light source to react with one or more predetermined responses and combinations of smart lighting and visible light communication. In these systems, light is generated using laser devices which are powered by one or more laser drivers. In some embodiments, individual laser devices are used and optical elements are provided to combine the red, green and blue spectra into a white light spectrum. In other embodiments, blue or violet laser light is provided by a laser source and is partially or fully converted by a wavelength converting element into a broader spectrum of longer wavelength light such that a white light spectrum is produced. The blue or violet laser devices illuminate a wavelength converting element which absorbs part of the pump light and reemits a broader spectrum of longer wavelength light. The light absorbed by the wavelength converting element is referred to as the “pump” light. The light engine is configured such that some portion of both light from the wavelength converting element and the unconverted pump light are emitted from the light-engine. When the non-converted, blue pump light and the longer wavelength light emitted by the wavelength converting element are combined, they may form a white light spectrum. In an example, the partially converted light emitted generated in the wavelength conversion element results in a color point, which is white in appearance. In an example, the color point of the white light is located on the Planckian blackbody locus of points. In an example, the color point of the white light is located within du′v′ of less than 0.010 of the Planckian blackbody locus of points. In an example, the color point of the white light is preferably located within du′v′ of less than 0.03 of the Planckian blackbody locus of points. In an example, the wavelength conversion element is a phosphor which contains garnet host material and a doping element. In an example, the wavelength conversion element is a phosphor, which contains an yttrium aluminum garnet host material and a rare earth doping element, and others. In an example, the wavelength conversion element is a phosphor which contains a rare earth doping element, selected from one or more of Nd, Cr, Er, Yb, Nd, Ho, Tm Cr, Dy, Sm, Tb and Ce, combinations thereof, and the like. In an example, the wavelength conversion element is a phosphor which contains oxy-nitrides containing one or more of Ca, Sr, Ba, Si, Al with or without rare-earth doping. In an example, the wavelength conversion element is a phosphor which contains alkaline earth silicates such as M2SiO4:Eu2+(where M is one or more of Ba2+, Sr2+and Ca2+). In an example, the wavelength conversion element is a phosphor which contains Sr2LaAlO5:Ce3+, Sr3SiO5:Ce3+or Mn4+-doped fluoride phosphors. In an example, the wavelength conversion element is a high-density phosphor element. In an example, the wavelength conversion element is a high-density phosphor element with density greater than 90% of pure host crystal. In an example, the wavelength converting material is a powder. In an example, the wavelength converting material is a powder suspended or embedded in a glass, ceramic or polymer matrix. In an example, the wavelength converting material is a single crystalline member. In an example, the wavelength converting material is a powder sintered to density of greater than 75% of the fully dense material. In an example, the wavelength converting material is a sintered mix of powders with varying composition and/or index of refraction. In an example, the wavelength converting element is one or more species of phosphor powder or granules suspended in a glassy or polymer matrix. In an example, the wavelength conversion element is a semiconductor. In an example, the wavelength conversion element contains quantum dots of semiconducting material. In an example, the wavelength conversion element is comprised by semiconducting powder or granules. For laser diodes the phosphor may be remote from the laser die, enabling the phosphor to be well heat sunk, enabling high input power density. This is an advantageous configuration relative to LEDs, where the phosphor is typically in contact with the LED die. While remote-phosphor LEDs do exist, because of the large area and wide emission angle of LEDs, remote phosphors for LEDs have the disadvantage of requiring significantly larger volumes of phosphor to efficiently absorb and convert all of the LED light, resulting in white light emitters with large emitting areas and low luminance. For LEDs, the phosphor emits back into the LED die where the light from the phosphor can be lost due to absorption. For laser diode modules, the environment of the phosphor can be independently tailored to result in high efficiency with little or no added cost. Phosphor optimization for laser diode modules can include highly transparent, non-scattering, ceramic phosphor plates. Decreased temperature sensitivity can be determined by doping levels. A reflector can be added to the backside of a ceramic phosphor, reducing loss. The phosphor can be shaped to increase in-coupling and reduce back reflections. Of course, there can be additional variations, modifications, and alternatives. For laser diodes, the phosphor or wavelength converting element can be operated in either a transmission or reflection mode. In a transmission mode, the laser light is shown through the wavelength converting element. The white light spectrum from a transmission mode device is the combination of laser light not absorbed by the phosphor and the spectrum emitted by the wavelength converting element. In a reflection mode, the laser light is incident on the first surface of the wavelength converting element. Some fraction of the laser light is reflected off of the first surface by a combination of specular and diffuse reflection. Some fraction of the laser light enters the phosphor and is absorbed and converted into longer wavelength light. The white light spectrum emitted by the reflection mode device is comprised by the spectrum from the wavelength converting element, the fraction of the laser light diffusely reflected from the first surface of the wavelength converting element and any laser light scattered from the interior of the wavelength converting element. In a specific embodiment, the laser light illuminates the wavelength converting element in a reflection mode. That is, the laser light is incident on and collected from the same side of the wavelength converting element. The element may be heat sunk to the emitter package or actively cooled. Rough surface is for scattering and smooth surface is for specular reflection. In some cases, such as with a single crystal phosphor a rough surface with or without an AR coating of the wavelength converting element is provided to get majority of excitation light into phosphor for conversion and Lambertian emission while scattering some of the excitation light from the surface with a similar Lambertian as the emitted converted light. In other embodiments such as ceramic phosphors with internal built-in scattering centers are used as the wavelength converting elements, a smooth surface is provided to allow all laser excitation light into the phosphor where blue and wavelength converted light exits with a similar Lambertian pattern. In a specific embodiment, the laser light illuminates the wavelength converting element in a transmission mode. That is, the laser light is incident on one side of the element, traverses through the phosphor, is partially absorbed by the element and is collected from the opposite side of the phosphor. The wavelength converting elements, in general, can themselves contain scattering elements. When laser light is absorbed by the wavelength converting element, the longer wavelength light that is emitted by the element is emitted across a broad range of directions. In both transmission and reflection modes, the incident laser light must be scattered into a similar angular distribution in order to ensure that the resulting white light spectrum is substantially the same when viewed from all points on the collecting optical elements. Scattering elements may be added to the wavelength converting element in order to ensure the laser light is sufficiently scattered. Such scattering elements may include: low index inclusions such as voids, spatial variation in the optical index of the wavelength converting element which could be provided as an example by suspending particles of phosphor in a matrix of a different index or sintering particles of differing composition and refractive index together, texturing of the first or second surface of the wavelength converting element, and the like. In a specific embodiment, a laser or SLED driver module is provided. For example, the laser driver module generates a drive current, with the drive currents being adapted to drive a laser diode to transmit one or more signals such as digitally encoded frames of images, digital or analog encodings of audio and video recordings or any sequences of binary values. In a specific embodiment, the laser driver module is configured to generate pulse-modulated signals at a frequency range of about 50 to 300 MHz, 300 MHz to 1 GHz or 1 GHz to 100 GHz. In another embodiment the laser driver module is configured to generate multiple, independent pulse-modulated signal at a frequency range of about 50 to 300 MHz, 200 MHz to 1 GHz or 1 GHz to 100 GHz. In an embodiment, the laser driver signal can be modulated by an analog voltage or current signal. FIG.8Ais a functional block diagram for a laser-based white light source containing a blue pump laser and a wavelength converting element according to an embodiment of the present invention. In some embodiments, the white light source is used as a “light engine” for static lighting, dynamic light, VLC, or smart lighting applications. Referring toFIG.8A, a blue or violet laser device1202emitting a spectrum with a center point wavelength between 390 and 480 nm is provided. The light from the blue laser device1202is incident on a wavelength converting element1203which partially or fully converts the blue light into a broader spectrum of longer wavelength light such that a white light spectrum is produced. A laser driver1201is provided which powers the laser device1202. In a preferred embodiment the laser diode device is a gallium and nitrogen containing laser diode device operating in the 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, or 490 nm to 550 nm range. For example, the laser diode is a blue laser diode with an output power of less than 1 W, or about 1 W to about 4 W, or about 4 W to about 10 W. In some embodiments, one or more beam shaping optical elements1204may be provided in order to shape or focus the white light spectrum. Optionally, the one or more beam shaping optical elements1204can be one selected from slow axis collimating lens, fast axis collimating lens, aspheric lens, ball lens, total internal reflector (TIR) optics, parabolic lens optics, refractive optics, or a combination of above. In other embodiments, the one or more beam shaping optical elements1204can be disposed prior to the laser light incident to the wavelength converting element1203. FIG.8Bis a functional block diagram for a laser-based white light source containing multiple blue pump lasers and a wavelength converting element according to another embodiment of the present invention. Referring toFIG.8B, a laser driver1205is provided, which delivers a delivers a controlled amount of current at a sufficiently high voltage to operate three laser diodes1206,1207and1208. In a preferred embodiment the laser diode devices are gallium and nitrogen containing laser diode devices operating in the 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, or 490 nm to 550 nm range. For example, the three laser diodes are blue laser diodes with an aggregated output power of less than 1 W, or about 1 W to about 6 W, or about 6 W to about 12 W, or about 12 W to 30 W. The three blue laser devices1206,1207and1208are configured to have their emitted light to be incident on a wavelength converting element1209in either a transmission or reflection mode. The wavelength converting element1209absorbs a part or all the blue laser light and emits photons with longer wavelengths. The spectra emitted by the wavelength converting element1209and any remaining laser light are collected by beam shaping optical elements1210, such as lenses or mirrors, which direct the light with a preferred direction and beam shape. Optionally, the wavelength converting element1209is a phosphor-based material. Optionally, more than one wavelength converting elements can be used. Optionally, the bean shaping optical elements can be one or a combination of more selected the list of slow axis collimating lens, fast axis collimating lens, aspheric lens, ball lens, total internal reflector (TIR) optics, parabolic lens optics, refractive optics, and others. Optionally, the beam shaping optical element is implemented before the laser light hits the wavelength converting element. In another embodiment, an optical fiber is used as the waveguide element wherein on one end of the fiber the electromagnetic radiation from the one or more laser diodes is in-coupled to enter the fiber and on the other end of the fiber the electromagnetic radiation is out-coupled to exit the fiber wherein it is then incident on the phosphor member. The optical fiber could have a transport length ranging from 100 μm to about 100 m, or to about 1 km, or greater. The optical fiber could be comprised of a single mode fiber (SMF) or a multi-mode fiber (MMF), with core diameters ranging from about 1 μm to 10 μm, about 10 μm to 50 μm, about 50 μm to 150 μm, about 150 μm to 500 μm, about 500 μm to 1 mm, or greater than 1 mm. The optical core material may consist of a glass such as silica glass wherein the silica glass could be doped with various constituents and have a predetermined level of hydroxyl groups (OH) for an optimized propagation loss characteristic. The glass fiber material may also be comprised of a fluoride glass, a phosphate glass, or a chalcogenide glass. In an alternative embodiment, a plastic optical fiber is used to transport the laser pump light. FIG.9Ais a functional block diagram for a laser-induced fiber-delivered white light source according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, the laser-induced fiber-delivered white light source has a laser driver1211configured to provide one or more driving currents or voltages or modulation control signals. The laser-induced fiber-delivered white light source also includes at least one blue laser device1212configured to emit a laser light with a blue wavelength in a range from about 385 nm to about 485 nm. Optionally, the at least one laser diode device1212is a LD chip configured as a chip-on-submount form having a Gallium and Nitrogen containing emitting region operating in one wavelength selected from 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, and 490 nm to 550 nm range. Optionally, the at least one laser diode device1212includes a set of multiple laser diode (LD) chips. Each includes an GaN-based emission stripe configured to be driven by independent driving current or voltage from the laser driver1211to emit a laser light. All emitted light from the multiple LD chips can be combined to one beam of electromagnetic radiation. Optionally, the multiple LD chips are blue laser diodes with an aggregated output power of less than 1 W, or about 1 W to about 10 W, or about 10 W to about 30 W, or about 30 W to 100 W, or greater. Optionally, each emitted light is driven and guided separately. In the embodiment, the laser-induced fiber-delivered white light source includes a waveguide device1214configured to couple and deliver the laser light from the at least one laser diode device1212to a remote destination. Optionally, the waveguide device1214is an optical fiber for being relatively flexibly disposed in any custom-designed light system. The optical fiber includes a single mode fiber or multiple mode fiber with a core diameter in a range selected from about 1 μm to 10 μm, about 10 μm to 50 μm, about 50 μm to 150 μm, about 150 μm to 500 μm, about 500 μm to 1 mm, or greater than 1 mm. Optionally, the waveguide device1214is a semiconductor waveguide pre-fabricated on a semiconductor substrate to fit a relative flexible light path in any custom-designed light system. The waveguide device1214can have an arbitrary length to deliver the laser electromagnetic radiation through a waveguide transport member which terminate at a light head member disposed at the remote destination. Optionally, the laser light exiting the light head is characterized by a beam diameter ranging from 1 μm to 5 mm and a divergence ranging from 0 degree to 200 degrees full angle. In the embodiment, the laser-induced fiber-delivered white light source also includes a wavelength converting element1215disposed in the light head member at the remote destination. Optionally, the wavelength converting element1215is a phosphor material configured to be a single plate or a pixelated plate disposed on a submount material completely separated from the laser diode device1212. Optionally, the phosphor material used in the fiber-delivered laser lighting system is comprised of a ceramic yttrium aluminum garnet (YAG) doped with Ce or a single crystal YAG doped with Ce or a powdered YAG comprising a binder material. The phosphor material is configured to convert at least partially the incoming laser electromagnetic radiation of a first wavelength (e.g., in blue spectrum) to a phosphor emission of a second wavelength. The second wavelength is longer than the first wavelength. Optionally, the second wavelength is in yellow spectrum range. Optionally, the phosphor material has an optical conversion efficiency of greater than 50 lumen per optical watt, greater than 100 lumen per optical watt, greater than 200 lumen per optical watt, or greater than 300 lumen per optical watt. Optionally, the phosphor material1215has a surface being placed at a proximity of the end section of the optical fiber or semiconductor waveguide in the light head member to receive the laser electromagnetic radiation exited from the waveguide device1214. Optionally, the laser electromagnetic radiation has a primary propagation direction which is configured to be in an angle of incidence with respect to a direction of the surface of the phosphor material in a range from 20 degrees to close to 90 degrees. Optionally, the angle of incidence of the laser electromagnetic radiation is limited in 25 to 35 degrees. Optionally, the angle of incidence of the laser electromagnetic radiation is limited in 35 to 40 degrees. Optionally, the end section of the waveguide device1214in the light head member is disposed in a close proximity relative to the surface of phosphor material so that laser electromagnetic radiation can land on the surface to form an excitation spot in a range of 25 μm to 5 mm. Optionally, the excitation spot is limited within 50 μm to 500 μm. The laser electromagnetic radiation at the excitation spot is absorbed by the phosphor material to induce a phosphor emission with a spectrum of longer wavelengths than the first wavelength of the incoming electromagnetic radiation. A combination of the phosphor emission of a second wavelength plus a partial mixture with the laser electromagnetic radiation of the first wavelength produces a white light emission. Optionally, the white light emission is substantially reflected from the surface of the phosphor material and redirected or shaped as a white light beam used for various applications. Optionally, the white light emission out of the phosphor material can be in a range selected from 10 to 100 lm, 100 to 500 lm, 500 to 1000 lm, 1000 to 3000 lm, and greater than 3000 lm. Alternatively, the white light emission out of the light head member as a white light source with a luminance of 100 to 500 cd/mm2, 500 to 1000 cd/mm2, 1000 to 2000 cd/mm2, 2000 to 5000 cd/mm2, and greater than 5000 cd/mm2. FIG.9Bis a functional block diagram for a laser-induced fiber-delivered white light source according to another embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, the laser-induced fiber-delivered white light source includes a blue laser device1222driven by a laser driver1221to emit a laser light with a blue emission characterized by a wavelength ranging from 395 nm to 550 nm. Optionally, the laser device is a laser diode (LD) chip configured as a Chip-on-submount form with a GaN-based emitting region operating in a first wavelength selected from 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, and 490 nm to 550 nm range. The laser light exits the emitting region as a beam of electromagnetic radiation with relatively large divergence. Optionally, the laser-induced fiber-delivered white light source includes one or more beam collimation and focus elements1223configured to confine or shape the beam of electromagnetic radiation. The one or more beam collimation and focus elements1223may include a collimation lens, a focus lens, a filter, a beam splitter for guiding the beam of electromagnetic radiation to a specific direction with reduced beam diameter and smaller divergence. In the embodiment, the laser-induced fiber-delivered white light source also includes a waveguide device1224. Optionally, the waveguide device1224is substantially similar to the waveguide device1214described in earlier sections. The waveguide device1224is configured to receive the laser beam with proper alignment to an output port of the laser package holding the blue laser device1222to couple the laser electromagnetic radiation into a narrowed light path in sufficiently high efficiency greater than 60% or even greater than 80%. The waveguide device1224is configured to deliver the laser electromagnetic radiation to a remote destination for various specific applications. In the embodiment, the laser-induced fiber-delivered white light source further includes a wavelength converting element1225. Optionally, the wavelength converting element1225includes at least a phosphor material disposed in a remote location completely separated from the laser devices and is able to receive the laser electromagnetic radiation exiting the waveguide device1224. The laser electromagnetic radiation interacts with the phosphor material within an excitation spot to induce a phosphor emission which has a second wavelength that is longer than the first wavelength of the laser electromagnetic radiation. A mixture of a portion of laser electromagnetic radiation of the first wavelength with the phosphor emission of the second wavelength produces a white light emission. The white light emission is used for many illumination and projection applications statically and dynamically. Optionally, the white light emission out of the phosphor material is achieved in 10 to 100 lm, 100 to 500 lm, 500 to 1000 lm, 1000 to 3000 lm, and greater than 3000 lm. Alternatively, the white light emission generated by the laser induced has a luminance of 100 to 500 cd/mm2, 500 to 1000 cd/mm2, 1000 to 2000 cd/mm2, 2000 to 5000 cd/mm2, and greater than 5000 cd/mm2. FIG.9Cis a functional block diagram for a multi-laser-based fiber-delivered white light source according to yet another embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, the multi-laser-based fiber-delivered white light source includes a first blue laser device1232, a second blue laser device1233, and a third blue laser device1234, commonly driven by a laser driver1231. Optionally, there can be more than three laser devices driven by one or more laser drivers. Optionally, each laser device is configured to emit a laser light with a blue emission in one wavelength ranging from 395 nm to 550 nm. Optionally, the wavelength range can be limited in one selected from 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, and 490 nm to 550 nm range. Optionally, each blue laser device,1232,1233, and1234, includes a laser diode (LD) chip configured in Chip-on-submount form with a Gallium and Nitrogen containing emitting region to emit the blue laser light. Optionally, all emitted blue laser light from the multiple laser diode devices can be combined to one laser beam by one or more beam coupling elements1235. Optionally, the one combined laser beam of the multi-laser-based filter delivered white light source is configured to provide a beam of electromagnetic radiation of a first wavelength in blue spectrum with an aggregated output power of less than 1 W, or about 1 W to about 10 W, or about 10 W to about 30 W, or greater. In the embodiment, the multi-laser-based fiber-delivered white light source includes a fiber assembly1236configured to align fiber core to the combined laser beam of electromagnetic radiation so that the about 60% or greater, or 80% or greater efficiency of the combined laser beam of electromagnetic radiation can be coupled into an optical fiber embedded within the fiber assembly1236. The fiber assembly1236is substantially similar the waveguide device1214and1224for delivering the laser electromagnetic radiation to a remote destination via a flexible or customized light path in the optical fiber with an arbitrary length (e.g., over 100 m). At the end of the optical fiber, the laser electromagnetic radiation of the first wavelength exits with a confined beam diameter and restricted divergence. In the embodiment, the multi-laser-based fiber-delivered white light source includes a wavelength converting element1237disposed in a light head member at the remote destination to receive the laser beam exiting an end section of the optical fiber. In a specific embodiment, the wavelength converting element1237includes a phosphor plate or a pixelated phosphor plate disposed in the light head member at proximity of the end section of the optical fiber so that the beam of electromagnetic radiation exited the optical fiber can land in an spot on an surface of the phosphor plate with a spot size limited in a range of about 50 μm to 5 mm. Optionally, the phosphor plate used in the fiber-delivered laser lighting system is comprised of a ceramic yttrium aluminum garnet (YAG) doped with Ce or a single crystal YAG doped with Ce or a powdered YAG comprising a binder material. The phosphor plate has an optical conversion efficiency of greater than 50 lumen per optical watt, greater than 100 lumen per optical watt, greater than 200 lumen per optical watt, or greater than 300 lumen per optical watt. The phosphor plate absorbs the blue emission lasering the beam of electromagnetic radiation of the first wavelength to induce a phosphor emission of a second wavelength in yellow or violet spectra range. Optionally, the phosphor emission of the second wavelength is partially mixed with a portion of the incoming/reflecting beam of electromagnetic radiation of the first wavelength to produce a white light beam. Optionally, the light head member is configured to set the relative position of the end section of the optical fiber on a sloped body to make an angle of incidence of the exiting electromagnetic radiation with respect to a direction of the surface of the phosphor plate in a range from 5 degrees to 90 degrees. Optionally, the angle of incidence is narrowed in a smaller range from 25 degrees to 35 degrees or from 35 degrees to 40 degrees. Optionally, the white light emission is sufficiently reflected out of the phosphor plate. In the embodiment, the multi-laser-based fiber-delivered white light source optionally includes one or more beam shaping optical elements1238. In an embodiment, the one or more beam shaping optical elements1238includes a light head member which provides a mechanical fixture for holding the end section of the optical fiber for outputting the laser electromagnetic radiation and supporting the phosphor plate via a submount. Optionally, the mechanical fixture includes a sloped metal body to support the end section of the optical fiber in an angled direction with respect to the phosphor plate which is disposed at a bottom region of the sloped metal body. Optionally, the mechanical fixture includes a heatsink associated with the submount to support the phosphor plate for facilitating heat conduction from the hot phosphor material to the heatsink during a heated wavelength conversion process when the laser beam with high power illuminates in a small excitation spot on the surface of the phosphor plate. Optionally, the mechanical fixture includes a reflecting semi-cone structure for facilitating collection of the white light emission from the surface of the phosphor plate. In another embodiment, the one or more beam shaping optical elements1238includes additional secondary optics elements for handling the white light emission generated by the multi-laser-based fiber-delivered white light source. These secondary optics elements include static free-space optical elements, fiber-based optical elements, semiconductor-based optical elements, or one or more optical elements that are dynamically controlled for providing smart lighting information or information projection. FIG.10Ais a simplified diagram illustrating multiple discrete lasers configured with an optical combiner according to embodiments of the present invention. As shown, the diagram includes a package or enclosure for multiple laser diode light emitting devices. In a preferred embodiment the laser diode light-emitting devices are gallium and nitrogen containing laser diode devices operating in the 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, or 490 nm to 550 nm range. For example, the multiple laser diode emitters are blue laser diodes with an aggregated output power of less than 1 W, or about 1 W to about 10 W, or about 10 W to about 30 W, or about 30 W to 100 W, or greater. Each of the devices is configured on a single ceramic or multiple chips on a ceramic, which are disposed on common heat sink. As shown, the package includes all free optics coupling, collimators, mirrors, spatially or polarization multiplexed for free space output or refocused in a fiber or other waveguide medium. As an example, the package has a low profile and may include a flat pack ceramic multilayer or single layer. The layer may include a copper, a copper tungsten base such as butterfly package or covered CT mount, Q-mount, or others. In a specific embodiment, the laser devices are soldered on CTE matched material with low thermal resistance (e.g., AlN, diamond, diamond compound) and forms a sub-assembled chip on ceramics. The sub-assembled chip is then assembled together on a second material with low thermal resistance such as copper including, for example, active cooling (i.e., simple water channels or micro channels), or forming directly the base of the package equipped with all connections such as pins. The flatpack is equipped with an optical interface such as window, free space optics, connector or fiber to guide the light generated and a cover environmentally protective. FIG.10Bis an example of enclosed free space laser module. A case1400is used for assembling a free-space mirror-based laser combiner. The laser module includes two electrical supply pins1410for providing driving voltages for the laser diodes1430. In a preferred embodiment the laser diode devices are gallium and nitrogen containing laser diode devices operating in the 395 nm to 425 nm wavelength range, 425 nm to 490 nm wavelength range, or 490 nm to 550 nm range. For example, the multiple laser diode emitters are blue laser diodes with an aggregated output power of less than 1 W, or about 1 W to about 10 W, or about 10 W to about 30 W, or greater. The case1400includes a hole for a fiber1460to couple with the light guide output combined from all laser diodes1430through the series of mirrors1450. An access lid1420is designed for easy access of free-space optical elements1440in the assembly. A compact plug-and-play design provides a lot of flexibilities and ease of use. FIG.10Cis a schematic of an enclosed free space multi-chip laser module with an extended delivery fiber plus phosphor converter according to a specific embodiment of the present invention. As shown, the enclosed free space multi-chip laser module is substantially similar to the one shown inFIG.10Awith two electrical supply pins1410to produce a laser light beam in violet or blue light spectrum. The multiple laser chips1430in the package equipped with free-space optics units1455provide substantially high intensity for the light source that is desired for many new applications. Additionally, an extended optical fiber1465with one end is coupled with the light guide output for further guiding the laser light beam to a desired distance for certain applications up to 100 m or greater. Optionally, the optical fiber can be also replaced by multiple waveguides built in a planar structure for adapting silicon photonics integration. At the other end of the optical fiber, a phosphor-based wavelength converter1470may be disposed to receive the laser light, where the violet or blue color laser light is converted to white color light1475and emitted out through an aperture or collimation device. As a result, a white light source with small size, remote pump, and flexible setup is provided. FIG.11is a perspective view of a fiber-delivered white light source including a general laser package and a light head member including a wavelength conversion phosphor member wherein the laser package and the light head member are linked to each other via a fiber assembly according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, a fiber-delivered white light source1500includes at least a general laser package1510for laser and a light head member1520connected by a fiber assembly1530. The general laser package1510is a metal case for enclosing a laser module therein having an electrical connector1512disposed through a cover member1511for providing electrical supply to the devices in the case. The bottom side (not visible) is for mounting to a heat conductive base for distributing heat out of the heat-generating laser device. The light head member1520is metal case with a sloped shape and a glass window1522covering the slopped facet, enclosing a phosphor material inside (not shown) for receiving laser light delivered by the fiber assembly1530and converting the laser emission to a white light emission. The bottom side (not visible) od the light head member1530is made by metal or other thermal conductive material for efficiently distributing heat generated by the phosphor material therein. The fiber assembly1530shown inFIG.11is visible with a semi-flexible metal armor used to protect the optical fiber inside throughout an extended length from a first end coupled to the general laser package1510and a second end coupled with the light head member1520at a remote destination. The extended length can be over 100 m. FIG.12is a top view of the general laser package ofFIG.11according to the embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, the electrical connector1512with multiple pins are disposed via an electrical feedthrough at the top cover member1511of the general laser package1510. The opposite side of the general laser package is a bottom member used for mounting the general laser package1510in applications. The bottom member is preferred to be made by metal or metal alloy material, for example, AlN, AlO, BeO, Diamond, CuW, Cu, or Silver, or other high thermal conductive materials for mounting on a heatsink to quickly distributing heat generated by laser devices inside the package1510. FIG.13is a top view of interior elements of the general laser package ofFIG.12including a blue-laser module mounted on an electronic circuit board according to the embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. The general laser package1510B ofFIG.13is substantially the same general laser package1510ofFIG.12with the top cover member1511being removed. As shown, the general laser package1510B encloses a board member1515on which the electrical connector1512and multiple resistors and capacitors or other electronic components are mounted. Primarily, a blue-laser module1580is disposed in a center region with multiple electrical pins plugged into the board member1515. A fixing member1516is placed on top of the blue-laser module1580for securing the mounting of the blue-laser module1580. An output port1587is coupled to the blue-laser module1580from one side thereof and also coupled to the fiber assembly (with the metal armor of the optical fiber being partially visible). In the embodiment, the blue-laser module1580is configured to generate high-power laser light for the fiber-delivered white light source1500(FIG.11). For example, the blue laser module contains one or more laser diode chips with gallium and nitrogen containing emitting region configured to generate a laser electromagnetic radiation of a first wavelength in blue spectrum range with a power less than 1 W, or about 1 W to about 3 W, or about 3 W to about 10 W, or about 10 W to 100 W, or greater than 100 W. FIG.14is a top view of the blue-laser module with opened lid according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, the blue-laser module1800is configured as a metal case1801(with lid opened) enclosing a support member1802for supporting multiple components: at least one laser diode device1810, a collimating lens1820, a thermistor1830, a beam splitter1840, a first photodetector1850, a focus lens1860, an output port1870, and a second photodetector1880. Optionally, the laser diode device1810is a configured to be a chip-on-submount (CoS) device having a Gallium and Nitrogen (GaN) containing active region which is driven to generate a laser light with primary emission spectrum in blue region ranging from 415 nm to 485 nm. Optionally, the laser diode device1810is mounted on a ceramic base member on the support member1802. In an embodiment, the ceramic base member is a High Temperature Co-fired Ceramic (HTCC) submount structure configured to embed electrical conductors therein for connecting the laser diode with its driver, and to provide sufficiently efficient thermal conduction for the laser diode during operation. In an embodiment, the laser light generated by the laser diode device1810exits with a large spread into a collimating lens1820to form a laser beam with a reduced spot size and a narrowed spread range. Optionally, the collimating lens1820is disposed in front of an exit facet of the GaN active region of the CoS chip1810and fixed by a weld clip. A thermistor1830is disposed near the laser diode device1810as a temperature sensor for monitoring temperature during operation. Optionally, an electrostatic discharge (ESD) Zener diode is included to protect the laser diode device from static electrical shock. In the embodiment, the beam splitter1840is disposed in the path of the collimated laser beam. Optionally, the beam splitter1840is a filter. Optionally, beam splitter1840is an optical crystal with a front facet and a back facet. The front facet of the beam splitter faces the incoming laser beam and is coated with an anti-reflection thin-film for enhancing transmission. Optionally, a small amount of laser light still is reflected. The first photodetector1850is placed (to the left) to detect the reflected light. Optionally, the photodiode1850is the first photodetector characterized to detect primarily blue emission for safety sensing of the laser diode device1810. The back facet of the beam splitter allows that a primary first portion of the laser beam is exited in a first direction while a minor second portion with the blue emission being substantially filtered is split to a second direction deviated from the first direction. The second photodetector1880is placed (to the right) to detect yellow spectrum for monitoring the second portion of the laser beam with the blue emission being substantially filtered. Optionally, an extra filter is placed in front of the second photodetector1880. In the embodiment, the primary first portion of the laser beam exited from the beam splitter1840is led to a focus lens1860disposed inside the metal case1801. Optionally, the focus lens1860is configured to confine the laser beam to much smaller size that can be coupled into an optical fiber. Optionally, the Optionally, the coupling efficiency of the laser beam into the optical fiber is achieved and maintained greater than 80%. Optionally, the focus lens1860is mounted to the output port1870from inside of the metal case1801. The optical port1870is 360-degree laser weld in a through hole at one side wall of the metal case1801. Referring toFIG.13, a first end of the fiber assembly1530is configured to couple with the output port which is denoted as1587. In the embodiment, the blue-laser module1800also includes multiple pins1890that are disposed at two opposite sides of the metal case1801. One end of each pin is connected to the electrical connector embedded in the ceramic base member. Another end of each pin is bended down to plug into the board member1515(seeFIG.13) so that the blue-laser module1800can receive electrical driver/control signals. FIG.15is a perspective view of the blue-laser module according to the embodiment of the present invention. Referring toFIG.15, it shows a substantially same blue-laser module ofFIG.14for better illustrating the structural layout of each components mentioned herein. FIG.16is (A) a top view of a general laser package, (B) a top view of interior elements of the general laser package including a blue-laser module, and (C) a top view of the blue-laser module according to another embodiment of the present invention. These diagrams are merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. In the embodiment shown in theFIG.16, in part A, the top cover member2011of a general laser package2010is seen with an electrical connector2012disposed therein. An output port2017is configured to couple with a fiber assembly. In part B, the general laser package2010B is shown without the top cover member2011. The electrical connector2012is seen mounted on a board member2015. A blue-laser module2080is partially visible is also mounted on the board member2015with several pins visibly located at two opposite sides while a large piece of fixing clip2016is placed on top of the blue-laser module2080. A focus lens2087is disposed outside the blue-laser module2080and coupled with the fiber assembly at the output port2017(see part A). In part C, the blue-laser module2080is shown as a metal case2081with its lid opened. The blue-laser module2080in the embodiment includes at least a laser diode device2082disposed on a support member2087to generate a laser light, a collimating lens2088disposed and aligned to one facet of an emitting stripe of the laser diode device2082in an optical path of the laser light, and a beam splitter2084disposed down-stream of the optical path of the laser light. Optionally, multiple laser diode devices configured respectively as Chip-on-Submount LD chips can be laid in the metal case2081of the blue-laser module for achieving higher laser power. Optionally, multiple laser beams from multiple LD chips can be combined to reach unified power of 6 W, or 12 W, or 15 W for obtaining a brighter white light. In the embodiment, the laser diode device2082includes an active region made by Gallium Nitride having the emitting stripe configured to emit light from one end facet. Optionally, the emitted light is substantially a blue emission with a wavelength in a range from 415 nm to 485 nm. The support member2087optionally is a High Temperature Co-fired Ceramic (HTCC) submount structure configured to embed electrical conducting wires therein. This type of ceramic support member provides high thermal conductivity for efficiently dissipating heat generated by the laser diode2082to a heatsink that is made to contact with the support member2087. The ceramic support member2087also can allow optimized conduction wire layout so that ESD can be prevented and thermal management of the whole module can be improved. Referring to part C ofFIG.16, at least two electrical pins2089are configured to connect with the conducting wires in the HTTC ceramic submount structure for providing external drive signals for the laser diode2082. Optionally, the blue-laser module2080includes a temperature sensor2083that can be disposed within the metal case on the support member and relative far away from the location of the laser diode2082. In the embodiment, the light generated by the laser diode device2082is led into the collimating lens2088so that the light can be confined with a smaller spread range to form a laser beam along a first direction (x). Optionally, the beam splitter2084is disposed down stream of an optical path along the first direction x, and is configured to split the laser beam to at least a first portion primarily in the first direction x and a second portion redirected to a second direction y. The first portion of the laser beam remains primarily a blue emission. The second portion may be filtered to eliminate the blue spectrum while retaining minor yellow spectrum. In the embodiment, the blue-laser module2080further includes a photo diode2085disposed in the path of the second direction y inside the metal case2081to detect the yellow spectrum. FIG.17is a partial cross-sectional view of an end section of a fiber assembly according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, in an embodiment, the end section of the fiber assembly1700is supposed to be coupled with the laser module1800(seeFIG.15). An optical fiber1701is embedded in the fiber assembly1700. Optionally, the optical fiber1701is comprised of a single mode fiber (SMF) or a multi-mode fiber (MMF), with core diameters ranging from about 1 um to 10 um, about 10 um to 50 um, about 50 um to 150 um, about 150 um to 500 um, about 500 um to 1 mm, or greater than 1 mm. The optical core material may consist of a glass such as silica glass wherein the silica glass could be doped with various constituents and have a predetermined level of hydroxyl groups (OH) for an optimized propagation loss characteristic. The glass fiber material may also be comprised of a fluoride glass, a phosphate glass, or a chalcogenide glass. In an alternative embodiment, a plastic optical fiber is used to transport the laser pump light. Optionally, most part of the optical fiber in a middle section of the fiber assembly1700is protected by a fiber jacket.FIG.17shows that an end section of the fiber assembly in a ferrule1702is terminated in a fiber termination adaptor1710. Optionally, the ferrule1702can be made by glass, or ceramic material, or metal material. Referring toFIG.15andFIG.17, the fiber termination adaptor1710is coupled with an output port by laser welding. In a specific embodiment, the fiber termination adaptor1710includes a precision circular rim made for laser welded at its perimeter with an inner diameter of a hole in a side wall of the laser module sub-package1800(seeFIG.15) for hermetical sealing. The fiber termination adaptor1710further has its end face1720being laser welded with a lens which essentially the focus lens1870(seeFIG.15) for hermetic sealing. Optionally, the focus lens1730(FIG.17) is also hermetically sealed around its perimeter in the lens structure1860(FIG.15). Optionally, during the fiber coupling process, an active alignment process is performed to simultaneously align a focus lens1730(or1860inFIG.15) to the fiber core1701such that the maximum amount of radiated power emitting from the laser diode through the focus lens1730is focused into the fiber1701. Both the focus lens1730and fiber1701must be manipulated in the X, Y, Z linear direction within micron precision. In addition, the angular rotation of each axis must also be controlled during the alignment procedure. At the same time, the fiber assembly1700involving the fiber core, ferrule, fiber termination adaptor, requires a hermetically sealed assembly in addition to the good alignment between fiber and focus lens such that a coupling efficiency is kept greater than 60% or even greater than 80%. FIG.18is a partial cross-sectional view of an end section of a fiber assembly according to another embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, in an alternative embodiment, a fiber assembly1900includes an end section having a ferrule1902enclosing the optical fiber1901therein except a small section of fiber core. On rest part (in the middle section) of the fiber assembly1900, the optical fiber1901is protected by a fiber jacket. The ferrule1902is capped by a fiber termination adaptor1910. In this embodiment, the fiber termination adaptor design is made to include a lens1930at its very end, allowing passive alignment of several relative positions between the lens1930and fiber core1901. In the embodiment, the lens1930can be disposed at a concentricity position via mechanical references, eliminating the X, Y motion requirement of the lens. A precision spacer (not shown) allows the Z-axis position to be passively obtained to achieve desired alignment with sufficiently high coupling efficiency. The fiber termination adaptor1910has a precision rim for laser welded at its perimeter with the inner diameter of a hole in the side wall of the laser module2080(seeFIG.16). Optionally, the fiber assembly1900can be actively aligned, during its welding process with the laser module2080, to the radiated power emitting from the laser diode with relaxed requirements. For example, the precision requirement can be relaxed to tens of microns instead of limiting to micron precision. FIG.19is a perspective view of the light head member ofFIG.11according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, a perspective view of the light head member2300includes a semi-open metal case2301with a slopped body2310. A second end of the fiber assembly1530is configured to have the optical fiber1535to pass through an input port2320and be bended in parallel with the slopped body2310. The slopped body2310further includes a reflecting semi-cone2330formed at a lower part where the optical fiber1535ended with a fiber head1538for guiding the laser beam into a surface of phosphor material2350with an angle. Optionally, the reflecting semi-cone2330is coated with a highly reflective material for white light. In the embodiment, the phosphor material2350is disposed at a bottom region of the reflecting semi-cone2330. The angle of the laser beam guided by the fiber head1538is relative to the surface of the phosphor material2350. Optionally, the angle of the laser beam hitting the surface of phosphor can be set in a range from 30 degrees to 35 degrees. As the laser beam with blue emission is directed from the fiber head1538into a small spot2355in the surface of the phosphor material2350, it excited the phosphor material2350to convert the received blue emission to a phosphor-excited emission with a longer wavelength (for example, a violet emission). Optionally, the spot size on the surface of the phosphor material2350is confined within 500 μm and even down to 50 μm. A mixing of the phosphor-excited emission with the blue emission of the laser beam forms a white light beam2340exiting (or substantially reflected by) upwards from the reflecting semi-cone2330. Optionally, the phosphor material is mounted on a heatsink to conduct heat quickly away from the excited phosphor material when it is illuminated by a high-power laser emission. Optionally, a glass window material is placed overlying the slopped body and allow the white light beam to pass through to serve as a white light source. Optionally, the white light source is configured to produce substantially pure white light with strong luminance of flux in 250, 500, 1000, 3000, and 10,000 cd/mm2. In an embodiment, the fiber assembly1530integrated in the fiber-delivered laser induced white light system1500(seeFIG.11) can be made to be detachable so that applications of the system can be more flexible for maintenance. For example, a portion of failed parts can be easily replaced without disrupting the whole system. Optionally, referring toFIG.11, the system1500can be provided with a detachable fiber termination adaptor (FTA) at an input port of the fiber assembly1530coupled with the main laser package1510. Optionally, any place in the middle section of the fiber assembly1530can be selected for forming a fiber coupling joint using either mechanical fiber-to-fiber coupling mechanism or optical recoupling mechanism.FIG.20shows an exemplary diagram of a fiber coupling joint made by mechanical butt coupler according to an embodiment of the present invention. As shown, each of two attachable sections of the fiber assembly1530are respectively terminated with two connectors2100and2200. Optionally, the connector2100is characterized by a total length L1including a connector length L2plus a boot2130and a connector size H. Each connector (2100) is coupled with the optical fiber (not explicitly shown) via a ferrule structure2110with one end being inserted into the connector2100with alignment to minimize fiber core offset, with eye-damaging prevention, and with dust protection. Another end of the ferrule is coupled first with a sleeve member2120before inserted into a bend-protection boot2130. Two connectors2100and2200are mated together when they are respectively inserted into two entries of a mating adaptor2010. The location of the coupling joint can be easily implemented into existing product. In another embodiment, the fiber connector sets for forming the coupling joint can be made with lenses for optical recoupling. In this case, free-space optical elements are used for ensuring good optical coupling with substantially free of mechanical misalignment. Optionally, the optical-recoupling set includes window(s) for conveniently cleaning. In yet another embodiment, referring toFIG.11, the system1500can be provided with a detachable fiber termination adaptor (FTA) at an output port of the fiber assembly1530coupled with the light head member1520. This option is substantially achieved like the FTA at the input port. FIG.21shows an application of a fiber-delivered white light source for street lighting according to an embodiment of the present invention. This diagram is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. As shown, the fiber-delivered white light source for street lighting includes a laser diode bank2800(containing one or more gallium and nitrogen containing laser diode chips) remotely disposed in a utility box or buried underground. A laser beam, substantially in blue emission in an embodiment, is delivered via an optical fiber2806from a bottom of a street light pole2805to its top where a phosphor member2810is set up. In the embodiment, the phosphor member2810is configured to receive the incident laser beam delivered by the optical fiber and generate a white light beam. Optionally, the white light beam is shaped by one or more optic elements to become wide angled beams2815. Provided a certain height of the street light pole2805, the wide-angled beams2815resulted a spread illumination region2825in an elongated shape along the street2820. The wide spread angle of the illuminated region of such street light with 100× higher luminance allows 3-5× reduction in numbers of street poles for the whole street light system. Additionally, since the laser diode bank is remotely disposed on or under the ground, no lift would be needed to change the bulb. This would make replacement or maintenance cost of the light system much lower. It would also make the street light pole less expensive since it would not need to support the heavyweight of all the electronics and lights. In an alternative embodiment, similar fiber-delivered white light source can be developed for bridge lighting wherein the laser diode bank2800can be disposed at two ends of the bridge on shoreline for easy access while each of all lighting elements disposed on bridge can be configured with a light head member containing a phosphor member2810to receive the lase electromagnetic radiation delivered by a waveguide transport element such as the optical fiber2806from the laser diode bank2800. Multiple fibers can be used to respectively deliver laser from the laser diode bank2800to multiple different light head members. The laser delivered by the optical fiber reaches a surface of a phosphor member in each light head member to generate a phosphor emission for producing a white light emission for illumination. Optionally, optics design allows the spread illumination region2825corresponding to each phosphor member2810to be respectively configured based on the bridge dimension and curvature to achieve best illumination or decoration effects with the most economic arrangement of positions, angles, heights of the light head member containing the phosphor member2810. In yet another embodiment, similar white light sources can be developed for application of tunnel lighting, down-hole lighting, stadium lighting, and many other special lighting applications that can take advantages of remotely delivering ultra strong visible lighting via the fiber-delivered white light source. In some embodiments the fiber delivered white light source could be used for data transmission from the light source to devices configured to receive the signal. For example, the laser based light source could be used for Li-Fi and visible light communication (VLC) applications to transmit at high data rates of greater than 1 Gb/s, greater than 5 Gb/s, greater than 10 Gb/s. greater than 50 Gb/s, or greater than 100 Gb/s. Such high data rates enable by used of the visible light spectrum with laser diodes could enable new capability for applications such as the internet of things (IOT), smart lighting, vehicle to vehicle communication, mobile machine communication, street lighting to vehicle communication, and many more. Additionally, the fiber delivered white light sources could be applied to LIDAR applications. While the above is a full description of the specific embodiments, various modifications, alternative constructions and equivalents may be used. As an example, the packaged device can include any combination of elements described above, as well as outside of the present specification. Although the embodiments above have been described in terms of a laser diode, the methods and device structures can also be applied to other stimulated light emitting devices. Therefore, the above description and illustrations should not be taken as limiting the scope of the present invention which is defined by the appended claims. | 167,976 |
11862941 | Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. DETAILED DESCRIPTION OF THE INVENTION In the following description of preferred embodiments, the same reference symbols denote the same or equivalent assemblies or components. The views in the accompanying figures are not drawn to scale, merely for the sake of better understanding. Referring now toFIG.1, which is a perspective view of a first embodiment of a multi-laser arrangement1according to the present invention in a view obliquely from the front and top. A housing2of multi-laser arrangement1includes a housing cap3which is secured to a base plate4in a fluid-tight and hermetically sealed manner. Housing cap3comprises or is made of a metal or a metallic alloy, in particular a deep-drawable metal or a deep-drawable alloy. As already mentioned above, the base plate4also comprises or is made of metal or of a metallic alloy and is joined to the housing cap3by welding. Only by way of example,FIG.9shows the weld seam S provided between housing cap3and base plate4, which extends substantially along the entire contact area between housing cap3and base plate4below a lateral projection As of housing cap3, which defines a welding flange. The process producing weld seam S is performed in a very short time interval, and the material of both housing cap3and base plate4is capable of dissipating the resulting heat in a way so that pedestal5and lasers6,7, and8disposed thereon, which are in the form of semiconductor lasers6,7, and8, are only slightly heated. As a result, neither these semiconductors nor any other semiconductor materials located in housing2, such as, for example, those of monitor diodes, are damaged or impaired. Moreover, flux, as used in soldering processes, for example, is not required, and the interior of housing2can be sealed reliably and fluid- and hermetically-tightly without detrimental components from the atmosphere, preferably under a protective gas atmosphere such as dry nitrogen. In the context of the present disclosure, an article, such as housing2of multi-laser arrangement1, is regarded as hermetically tight or fluid-tight if it exhibits a leak rate of less than 1·10−3mbar·l/s when filled with He and at a pressure difference of 1 bar at room temperature. Herein, He is used to mean Helium, when used as in the previous sentence, and He is also used to represent a distance or height, as in height He, the use of He herein is clear by the context in which He is used. Preferably, however, a leak rate of 1·10−8mbar·l/s is achieved when filled with He and at a pressure difference of 1 bar. Since the level of tightness to be achieved can depend on the internal volume of the housing, the tightness achieved in the present case ensures that a partial pressure of water in the housing of the multi-laser arrangement does not exceed 5000 ppm during the entire service life of the component. Furthermore, this welded joint contributes to the fact that housing2complies with method 1014 and method 1018 of the MIL-STD 883 standard under long-term continuous operation. A pedestal5is arranged on base plate4or, in other embodiments, is defined by base plate4itself, for example, in the embodiments shown inFIGS.9,10,17-21,24,26,27,28,31,32A,32B,32C and32D. In preferred embodiments, housing2accommodates a first laser6emitting in the red spectral range of the visible spectrum, a second laser7emitting in the green spectral range of the visible spectrum, and a third laser8emitting in the blue spectral range of the visible spectrum. Alternatively, more than one of lasers6,7,8or all lasers6,7,8may emit light in the same spectral range, which may be advantageous, for example, when multi-laser arrangement1is employed for lighting purposes. Each of the aforementioned lasers6,7, and8is arranged on pedestal5and is attached thereto such that each of these lasers6,7, and8is arranged at a predefined spacing from lower surface9of base plate4. Lower surface9of base plate4refers to the underside thereof, as seen inFIG.3, for example. This defines a predefined position of lasers6,7, and8with respect to the spacing from lower surface9of base plate4for the installation of the multi-laser module, which allows multi-laser arrangement1to be precisely installed in further assemblies. As an alternative to arranging respective separate lasers6,7, and8, these lasers may optionally also be provided in the form of a pre-assembled multi-laser module with the lasers already aligned to one another. This is further promoted by the fact that lasers6,7, and8are each arranged on pedestal5in alignment with one another. In order to contribute to, or allow, the alignment of lasers6,7, and8relative to one another with high precision during assembly, depressions E6, E7, and E8are provided in the upper surface of pedestal5for accommodating respective lasers6,7, and8, so that they are aligned relative to one another and preferably in a form-fitting manner, as can be seen inFIGS.5and6, for example. Depressions E6, E7, and E8may already be stamped into pedestal5during manufacture thereof, or may be produced by an independent precise manufacturing step, for example by a material-removing process such as milling or spark erosion. This also supports automated fabrication of multi-laser arrangement1, for example by pick-and-place production techniques. In this case, the distance of lasers6,7, and8in a Z direction will not be defined by a height H of the upper surface of pedestal5from lower surface9(or underside9) of base plate4, as in the further disclosed embodiments, instead, the respective distance He results from the height He as indicated inFIG.6, that is from the respective distance between the lower surface9or underside9of base plate4and countersunk surface OE6, OE7, or OE8of depression E6, E7, or E8. As far as specific dimensions are disclosed for height H, these shall in general similarly apply to the height He for the embodiment described in the present and the preceding paragraph. In more detail, pedestal5may have a height of between 0.5 and 1 mm, and height He may accordingly be between 0.35 and 0.9 mm. The aforementioned alignment may include that the main emission direction H6, H7, and H8of lasers6,7, and8is parallel to one another and that the spacing between front light exit faces10,11, and12, that is the exit faces of the respective useful light of lasers6,7, and8is predefined in the lateral direction, so that an exactly predefined connection geometry is already obtained for an optical assembly to which multi-laser arrangement1is to be connected, which allows multi-laser arrangement1to be precisely installed in further external assemblies, see, for exampleFIG.2, in which this orientation of the main emission directions H6, H7, and H8can be seen. In order to be able to define the terms “laterally”, “in front of”, “behind”, “above” or “below” more clearly, reference is made toFIG.4which shows a further perspective view of the first embodiment of the multi-laser arrangement according to the invention as shown inFIGS.1to3and coordinate axes X, Y, and Z of a Cartesian coordinate system, with reference symbols X, Y, and Z marking the end of the respective double arrow pointing in the positive direction. The wording “laterally aligned arrangement” thus refers to the respective spacing between lasers6,7, and8, in particular the spacing of their front light exit faces10,11and12in the Y direction. As mentioned above, the position of the level of lasers6,7, and8, i.e. their location relative to the Z direction, is defined by the distance between lower surface9of base plate4and height H of pedestal5, which can also be seen inFIG.6, by way of example. What can also be clearly seen in thisFIG.6is that, in this embodiment, the underside of pedestal5is exposed at the bottom, so that a downward connection can be made to a further assembly, which is however not illustrated in the figures, and that the underside of pedestal5is flush with the plane defined by the lower surface or underside9of base plate4. An emission of laser light in the positive X direction is referred to as being directed forward, and an emission of laser light in the negative X direction is referred to as being directed backwards or rearwards. In front of front light exit faces10,11, and12of lasers6,7, and8, an opening13is provided in housing cap3, to which a transparent element14is attached from the inside of housing2, see, e.g.,FIG.4and others. Transparent element14may comprise glass or may be made of glass. Here, the wording “comprise glass” is also intended to indicate that the transparent element may be coated or, depending on the application, may even have multiple layers, for example with color filter assemblies. However, in many of the embodiments of multi-laser arrangement1discussed in more detail below, it will not be necessary to apply for instance an anti-reflective coating to transparent element14, for example due to an inclination or tilt of transparent element14relative to main emission direction H6, H7, and H8of lasers6,7, and8. In a preferred embodiment, transparent element14is fixed on housing cap3or on a frame R by a glass solder, which frame R can be easily seen inFIG.9, for example, and which is itself fixed on housing3by a soldering process in this embodiment. This frame R may be made of “Alloy 52”, for example, a NiFe alloy, and can be produced as a drawn part with a thickness of about 0.15 mm. In an alternative embodiment, transparent element14itself is fixed on housing cap3by a gold solder, for example an AuSn solder. The use of gold solder allows for the direct attachment of window14to housing cap3, with fewer requirements on the structural dimensions both on transparent element14and on housing cap3. A corresponding comparison will be apparent fromFIGS.17and18.FIG.17shows a cross-sectional view of an embodiment of multi-laser arrangement1that is also referred to as a third embodiment, with the sectional plane in parallel to a side wall of housing cap3in the area of connection line Z to one of lasers6,7or8, in which transparent element14is attached to frame R using a glass solder G, and frame R in turn is fixed on housing cap3. FIG.18shows a cross-sectional view of an embodiment of multi-laser arrangement1, similar to the third embodiment mentioned above, obliquely from the front, with the sectional plane again in parallel to a side wall of housing cap3in the area of connection line Z to one of lasers6,7or8, in which transparent element14is fixed on housing cap3by an AuSn solder A. It is apparent here that the area on housing cap3covered by transparent element14or frame R is smaller when using the gold solder A than when using glass solder G, and as a result, housing2itself may also become smaller. For example, a width Bg of the layer of solder glass G that holds transparent element14or frame R can be reduced from 0.85 mm to a width Ba of 0.35 mm when a gold solder A is used. As a result, height Hg of housing2shown inFIG.17, which has a rectangular cross section and in which glass solder G was used, can be reduced from approximately 3.16 mm, for example, to height Ha of about 2.16 mm, for example, of housing2shown inFIG.18, which also has a rectangular cross section and in which gold solder A was used. Together with the reduced height Ha extending in the Z direction, the further dimensions of housing cap3in the X and Y directions and thus of housing2can also be reduced approximately proportionally to this reduction, by the factor Ha/Hg. A further reduction in height of housing2can be achieved if at least that wall of housing cap3on which transparent element14is arranged is inclined relative to base plate3. FIG.31shows the comparison of multi-laser arrangements1with a housing cap3of rectangular cross-section on the left side of this figure and a housing cap3with an angled, in particular inclined housing wall carrying transparent element14on the right side thereof. The angle of inclination a shown in the embodiment illustrated on the right ofFIG.31may be 45°, for example, as shown in this figure. As a result, the height of housing2can be reduced by approximately the amount of cos(45°) and thus by approximately a factor of 0.7. In further embodiments, instead of being exactly 45°, the angle of inclination a of the wall of housing cap3, relative to the normal direction N of the lower surface9of base plate4, may, more generally, also be in a range from 35° to 60°, preferably from 40° to 50°, most preferably in a range from 43° to 48°. Overall, the measures described above result in attractive changes in the size of housing2, in particular, in its height, which are shown inFIGS.32A-32D, by way of example and true to scale. FIGS.32A to32Dshow a comparison of the different designs of multi-laser arrangements1with a rectangular housing cap3and a housing cap3with an angled housing wall carrying transparent element14, in each case in a cross-sectional view in which the sectional plane is parallel to a side wall of housing cap3in the area of connection line Z to one of lasers6,7or8. FIG.32Ashows a housing2of rectangular cross section, in which transparent element14is fixed to housing cap3by a glass solder, in particular using a frame R, and in which a height of housing of 3.16 mm is obtained, as mentioned above. FIG.32Bshows a housing2of rectangular cross section, in which transparent element14is fixed to housing cap3by a gold solder and in which a height of the housing of approximately 2.16 mm is achieved, as mentioned above. FIG.32Cshows a housing2in which transparent element14is fixed to an inclined wall of housing cap3using a glass solder, whereby a height of the housing of approximately 2.52 mm is achieved. FIG.32Dshows a housing2in which transparent element14is fixed to an inclined wall of housing cap3using a gold solder, whereby a height of the housing of approximately 2.12 mm is achieved. This housing height is extremely attractive for many in particular mobile applications, of which only one is shown inFIG.33in the form of AR glasses, by way of example, which will be described in more detail further below. The angle of inclination a of transparent element14as illustrated in the embodiment shown on the right ofFIG.31may contribute to further structural advantages, in particular if, for example, a monitor diode19,20, and/or21is arranged below transparent element14and laser light reflected back from transparent element14is incident on monitor diode19,20, and/or21, as shown inFIGS.1,2, and8by way of example, to which reference will be made below. FIG.8shows a perspective cross-sectional view of the first preferred embodiment, in which the sectional plane is parallel to a side wall of the housing cap in the area of connection line Z to one of lasers6,7, or8. Monitor diodes19,20, and21are disposed below transparent element14, each one receiving light from an associated laser6,7, or8, which is reflected back from transparent element14. Merely by way of example, this is described below with reference to the main emission direction H6of laser6which emits light in the red spectral range. The light exiting laser6in main emission direction H6is incident on transparent element14and, since the latter is arranged at an angle of 45° relative to main emission direction H6, a reflected portion thereof is deflected vertically downwards, onto monitor diode19. This similarly applies to the light from laser7in main emission direction H7and reflected perpendicular thereto and to monitor diode20, and to the light from laser8in main emission direction H8and reflected perpendicular thereto and to monitor diode21. The intensity of the respective reflected light portion is sufficient to obtain a very precise sensor signal for the respective intensity of the light emitted by lasers6,7, and8. It is advantageous here if the light emerging from FAC lens18after leaving FAC lens18through exit face22thereof only exhibits slight beam divergence in the horizontal direction, i.e. in the Y direction, in particular in order to thereby avoid undesirable faulty light for the respective further monitor diodes. In the preferred embodiments of multi-laser arrangement1, Fast Axis Collimation (FAC) lens18is arranged on pedestal5, preferably spaced apart from the end face of lasers6,7, and8, the end faces of lasers6,7, and8corresponding to the already discussed light exit faces10,11, and12of these lasers6,7, and8. In this way, very effective beam shaping can be achieved, and the spacing allows to minimize thermal impacts such as caused by pedestal5heating up. This allows the arrangement to generate light beams leaving the respective laser6,7, or8in the respective main emission direction H6, H7, or H8with a beam diameter Ds in Y direction of only about 0.3 mm, for example. If monitor diodes19,20, and21each include color filters, in particular color filters in the form of a bandpass for the respective emission wavelength of the respectively associated laser6,7, or8, this allows them to suppress the light from the respective further lasers and to obtain a better signal-to-interference signal or better signal-to-noise ratio of the sensory signals of monitor diodes19,20, and21in this embodiment as well as in all other presently disclosed embodiments using these monitor diodes19,20, and21. An alternative arrangement in which transparent element14is in the form of an FAC lens (fast axis collimation lens)15or comprises an FAC lens (fast axis collimation lens)15is shown inFIG.22. In this case, FAC lens15may be placed on a plane-parallel substrate16or may be provided in the form of an integrally shaped FAC lens15, for example by being stamped into a corresponding shape. FIG.22furthermore shows that the inner surface of housing cap3is blackened, in particular blackened with a matt finish, as indicated by reference symbol T. For this purpose, a paint or a coating such as a black chrome coating or zinc-nickel coating can be used, in particular also as an electrolytic coating. By way of example,FIG.21shows the second embodiment of multi-laser arrangement1illustrating the absorption of the light emerging from the rear light exit face of lasers6,7, and8on a coated housing cap3. Since many coatings might interfere with the welding, the welding flange as defined by lateral projection As and on which weld seam S is formed, as also shown inFIG.9by way of example, may be kept free of the coating on the underside of housing cap3, so that the coatings described here will not have any adverse impact on the hermetic joint between housing cap3and base plate4. As an alternative, monitor diodes19,20,21may also be arranged behind lasers6,7, and8, in particular on a carrier23associated therewith, as is shown inFIGS.12and14by way of example. In the embodiment shown inFIGS.12and13, the light exiting rearwards from lasers6,7, and8is reflected on the inclined rear wall of housing2and is then incident on monitor diodes19,20, and21which are disposed directly above their respective connection lines Z. FIG.12shows a perspective cross-sectional view of a fifth embodiment of multi-laser arrangement1, with the sectional plane in parallel to a side wall of housing cap3in the area of the connection line Z to one of the lasers, andFIG.13shows a detail of a plan view of base plate4of the fifth embodiment shown inFIG.12, with housing cap3omitted. As an alternative, monitor diodes19,20, and21may also be arranged on a carrier23as shown inFIGS.14,15, and16, which preferably comprises ceramics or is made of ceramics. FIG.14shows a perspective cross-sectional view of a sixth embodiment of multi-laser arrangement1, with the sectional plane in parallel to a side wall of housing cap3in the area of the connection line Z to one of the lasers. FIG.15shows a plan view of base plate4of the sixth embodiment, shown inFIG.14, with housing cap3omitted, and from this view as well as fromFIG.16it can be seen that, in this embodiment, the normal direction Nt of the surface of carrier23on which monitor diodes19,20,21are arranged, is provided at an inclination relative to main emission direction H7of at least laser7, which inclination relative to main emission direction H7is in an angular range of angle β from 3° to 15°, preferably from 5° to 10°, most preferably from 6° to 8°. As shown inFIG.16, monitor diodes19,20, and21may each be electrically connected via conductors disposed on ceramic carrier23, of which conductors24and25are shown as an example for monitor diode19inFIG.16. Similarly as disclosed for carrier23, the wall of housing cap3on which transparent element14is arranged may also be provided at an inclination relative to the main emission direction of at least one of the lasers, which is shown inFIGS.23and24by way of example. FIGS.23and24each show a view of an eighth embodiment of multi-laser arrangement1, in which the normal direction Nw of at least that wall of housing cap3on which transparent element14is arranged is inclined relative to main emission direction H6of at least laser6, which inclination at an angle γ relative to the main emission direction is in an angular range from 3° to 15°, preferably from 5° to 10°, most preferably from 6° to 8°. FIG.27shows a cross-sectional view of a tenth embodiment in which the light exiting from a laser6is directed, i.e. injected into an optical fiber27that has its entry end26arranged close to light exit face12of laser6, which fiber27is fixed on housing cap3or on a transparent element14having feedthroughs for fiber27by substantially spherical fused glass28,29. As shown for laser6, further fibers can be similarly arranged for lasers7and8and fixed on housing cap3or transparent element14. In a further embodiment, transparent element14may else be provided in the form of a fiber board17or may comprise a fiber board17, as shown inFIG.28, by way of example. Such a fiberboard which is known to the person skilled in the art includes a large number of optical fibers arranged next to one another, and light incident onto fiberboard17is guided in these fibers so that the divergence of the light from lasers6,7, and8is thereby reduced and the light can be guided substantially in parallel. Another embodiment, in which housing cap3has a plurality of openings30,31, and32, is shown inFIGS.25and26. FIG.25shows the perspective view of a housing cap3of a ninth embodiment of multi-laser arrangement1, in which transparent element14has been omitted and in which housing cap3has three openings30,31, and32for the passage of laser light. FIG.26is a cross-sectional view of the ninth embodiment of the multi-laser arrangement corresponding to the housing cap as shown inFIG.25, with the sectional plane in parallel to the upper wall of housing cap3directly below the upper wall of housing cap3, where it can be seen that boundaries are provided for the laser light passing through openings30,31, and32, which boundaries laterally restrict the respective laser light and can thus contribute to a suppression of spurious light. In this embodiment, each of these openings30,31, and32may have a separate transparent element14associated therewith, or all of these openings may share one common transparent element14associated therewith. FIGS.25and26also show protective means33for glass of transparent element14provided on housing2, in particular in the form of a portion34laterally protruding beyond transparent element14. A further advantageous embodiment can be seen inFIGS.29and30, withFIG.29showing a twelfth embodiment of multi-laser arrangement1, in which base plate4is in the form of a carrier for optical assemblies and protrudes forward from below housing cap3, and withFIG.30showing a detail of the perspective view ofFIG.29with lasers6,7, and8in operation, with their respective beam paths and main emission directions H6, H7, and H8. The optical assemblies may, for example, include beam collimators35,36,37and dichroic beam splitters or beam combiners38,39,40, and may in this way allow to supply the light from lasers6,7, and8to other assemblies in a very compact space, coaxially and as if it comes from a single virtual source. All the embodiments presently described have in common that an electrical connection line Z, Z1, Z2, Z3is routed through housing2to a respective laser6,7,8, as can be seen inFIG.3by way of example. If, for example, base plate3of housing2is designed to be on reference potential and carries current, this allows to provide a multi-laser arrangement which can be operated with just four electrical connections. Furthermore, in particular in order to contribute to long-term operational durability and hermeticity of housing2, glass-to-metal feedthroughs may be provided in base plate4for connection lines Z, Z6, Z7, Z8to lasers6,7, and8and for further connection lines19,20, and21to monitor diodes19,20,21, as illustrated inFIG.3by way of example. As shown inFIG.7by way of example, these connection lines Z, Z6, Z7, Z8may also be routed to lasers6,7, and8via bonding wires B6, B7, and B8. In order to gain a better understanding of the structural relationships,FIG.5shows a perspective view, obliquely from the front and top, of a modification of base plate4with pedestal5of the first embodiment of the multi-laser arrangement1according to the invention as shown inFIGS.1to4, which is provided with depressions E6, E7, and E8in pedestal5for arranging the respective laser6,7, and8, andFIG.6is a cross-sectional view of the base plate along sectional plane A-A′ as shown inFIG.5. For example, the glass-to-metal feedthroughs for the connection lines to the lasers and/or to the monitor diodes may have a height Hd of 0.75 mm, and base plate4may have a thickness D of approximately 0.25 mm. An exemplary application is illustrated in the perspective view ofFIG.33in the form of AR glasses41which include multi-laser arrangement1according to the present invention arranged in a glasses temple, as will now be explained in more detail. The light emitted by multi-laser arrangement1is fed to optical assemblies42which have a beam-shaping effect and feed this light to a projection device43which produces a projection onto a spectacle lens of AR glasses41, superimposed on the natural image visually perceived by a user. Further sensors44,45, and46are used to recognize the environment and to identify the user. Exchangeable spectacle lenses47increase user comfort. A wireless transmission module49, in particular a 5G module, allows communication with external devices, in particular mobile external devices, in particular under the control of a processor48. A rechargeable battery50is connected to the electronic assemblies of AR glasses41via a safety device51and provides for mobile operation thereof. Referring now toFIG.34which shows a thirteenth embodiment of multi-laser arrangement1in which housing cap3has a plurality of openings for the passage of laser light, with a respective hot-formed optical element52,53,54held in each one thereof. Each of optical elements52,53,54defines a transparent element14which, as disclosed herein, is held in housing cap3in a hermetically sealed and fluid-tight manner, as is the case with the optical elements of the embodiments shown inFIGS.35,36, and37. In this thirteenth embodiment, optical elements52,53,54can be hot-formed in housing cap3, for example by introducing a glass blank of the respective optical element52,53,54into the respective opening30,31,32of housing cap3and heating it long enough, in particular to above the glass transition temperature Tg and the hemispherical temperature of the glass the blank is made of until the shape of the respective optical element52,53,54forms due to the surface tension of the glass of the respective blank. Housing cap3advantageously defines a circumferential annular flange55around each opening30,31,32, which is only shown for opening30, by way of example, and which is delimited radially by an annular circumferential recess or groove56. This provides a very precise outer frame at the radially outer end of annular flange55for the molten glass that is hot-shaped under its surface tension, which allows to precisely form a predefined surface of the respective optical element52,53,54. Referring now toFIG.35which shows a perspective cross-sectional view of a fourteenth embodiment of multi-laser arrangement1. In this embodiment, again, housing cap3defines a plurality of openings30,31,32for the passage of laser light, however with a preformed, in particular biconvex optical element57,58,69arranged in each one thereof, preferably in the form of a spherical lens. Optical elements57,58,69are each surrounded by a glass solder60annularly surrounding the respective optical element57,58,69in contact with the latter and housing cap3to hold it on housing cap3in a fluid-tight and hermetically sealing manner. For the sake of clarity, however, only glass solder60of optical element59has been designated by a reference numeral. Instead of spherical optical elements57,58,69it is also possible to use other lens shapes for the respective optical elements, as will be explained in more detail below by way of example, and as defined in the appended claims. For example, these may include spherical plano-convex or concavo-convex lenses, spherical or hemispherical lenses, aspherical plano-convex or concavo-convex lenses. FIG.36shows a perspective cross-sectional view of a fifteenth embodiment of multi-laser arrangement1, in which housing cap3has a plurality of openings30,31,32for the passage of laser light, with a respective preformed, in particular plano-convex optical element61,62,63held in each one thereof, preferably by a solder glass64. The in particular plano-convex optical elements61,62,63were preferably shaped by mechanical polishing. The optical elements disclosed inFIG.37which shows a sixteenth embodiment of multi-laser arrangement1, each constitute preformed, in particular aspherical optical elements, by way of example, and are in particular fixed on housing cap3by having been thermally fused thereto, and/or preferably by mechanical pressure. Only element65of these optical elements is designated by a reference symbol, by way of example. In order to be able to apply the necessary mechanical pressure forces, front wall66of housing cap3is formed with a greater wall thickness. In this case, housing wall66may in particular also provide a compression glass seal for optical element65pressed into it in a hot state. FIG.38shows a seventeenth embodiment of multi-laser arrangement1in which the area facing the light exit face of lasers6,7,8inside housing1and in particular also area67of pedestal5and of base plate4facing transparent element14have an absorbent coating. This coating may comprise an absorbent Ni coating, also referred to as dull Ni plating in this technical field. The connection line Z can preferably be gold-plated, in particular in order to increase its conductivity and corrosion resistance. FIGS.39and41show an eighteenth embodiment of multi-laser arrangement1. In this embodiment, the light exiting from a laser6,7,8is injected into a respective fiber68,69,27that has its entry end arranged close to the light exit faces of laser6,7,8, see, e.g., alsoFIG.41with a corresponding arrangement of fibers27,68,69. Each of fibers27,68,69is held on housing cap3by a male-type part70of an optical connector71and thus forms part of a releasable optical connection, in particular a releasably mateable optical plug-in connection71, each of which comprises a second, female-type part72engaging over male-type part70and each holding an external optical fiber73,74,75. female-type part72may also hold all external fibers73,74,75together in a single housing part, so that an optical plug-in connection to multi-laser arrangement1is established, which has the potential of greatly simplifying and also standardizing the integration thereof into other existing optical systems. The nineteenth embodiment of multi-laser arrangement1as shown inFIG.40differs from the one shown inFIG.39substantially by the fact that external fiber75is directly routed to light exit face10,11,12of a respective laser6,7,8in each case, and that female-type part72of optical connector1is fixed hermetically tightly on housing cap3, whereby a permanent connection to housing cap3is provided. FIG.41shows a cross-sectional view of a twentieth embodiment of multi-laser arrangement1, with the sectional plane in parallel to the upper wall of housing cap3directly below the upper wall of housing cap3. The light exiting from a laser6,7,8is injected into a respective fiber68,69,27that has its entry end arranged close to the light exit faces of laser6,7,8, which fiber is fixed on housing cap3and is terminated by a plug-in connection71with an external fiber73,74,75, as described above for the embodiment ofFIG.39. An optional lens array76or injection lenses76may inject the light from lasers6,7,8into the respective core of the respective fibers27,61,62, preferably matched with their numerical aperture. Fibers73,74and75are combined to form a fiber bundle77, and the intensity distribution of the fiber bundle at exit end78thereof is shown inFIGS.42A,42B, and42D, by way of example. FIG.42Ashows the intensity distribution at exit end78of a bundle77of optical fibers coupled to the multi-laser arrangement, perpendicular to the longitudinal extension of fiber bundle77, in which the individual fibers73,74,75, each one coupled to a laser of the multi-laser arrangement, are arranged next to one another in a plane, as viewed from the direction of arrow P inFIG.41. Advantageously, the line direction Ze of an associated imaging device also extends in this plane in which fibers73,74,75are arranged next to one another, so that during a respective image build-up the colors red, blue, and green are superimposed, and because of this superimposition no splice connection will be required for fibers73,74,75. Consequently, this allows to keep the length of fiber bundle77extremely short, in particular at about a few millimeters. FIG.42Bshows the intensity distribution of optical fibers73,74,75of a fiber bundle77, each coupled to multi-laser arrangement1, at exit end78of the bundle perpendicular to the longitudinal extension of fiber bundle77, in which the individual fibers, each one coupled to a respective laser of the multi-laser arrangement, are positioned next to one another in a spatial arrangement as close as possible, which can be advantageous for further optical systems in which this spatial spacing of fibers73,74,75is already sufficient to represent an image point, i.e. pixel, of an imaging system. FIG.42Cshows a cross-sectional view of optical fibers73,74,75each one coupled to multi-laser arrangement1, with the sectional plane B-B′ as shown inFIG.41perpendicular to the longitudinal extension of the fiber bundle at a distance from the exit end thereof, in which the individual fibers73,74,75, each one coupled to a laser6,7,8of multi-laser arrangement1, are positioned in a spatial arrangement next to one another as close as possible, and with a diffuser element79arranged between fibers73,74,75and extending along the longitudinal extension of fibers73,74,75. This allows light to be coupled from one fiber73,74,75into another fiber73,74,75and thereby provides a central region80of mixed light from all fibers73,74,75. FIG.42Dshows the intensity distribution of optical fiber bundle77as shown inFIG.42Cand coupled to multi-laser arrangement1at exit end78of the bundle perpendicular to the longitudinal extension of fiber bundle77. FIG.43shows an exemplary perspective view, partially broken-away, of further AR glasses41′, in which multi-laser arrangement1according to the invention is connected to a further optical assembly42via an optical fiber, in particular via fiber bundle77. The inventors have found that in the embodiments of AR glasses shown inFIGS.33and43, for example, deposits may accumulate on transparent element14during everyday operation, in particular particulate deposits such as dust particles. Such deposits might scatter and also reflect back the light emitted by lasers6,7,8. An exemplary deposit in the form of a grain of dust, St, is shown inFIG.4by way of example, and is enlarged for the sake of clarity. This may have detrimental effects, for example if part of the back-reflected light enters the cavity of one of lasers6,7, or8and causes coupling with the resonator modes therein, which may lead to an effect known as mode hopping resulting in undesirable fluctuations in the intensity of the laser light. In contrast to the majority of the conventional applications, a deformation of housing2of the embodiments of AR glasses shown inFIGS.33and43may furthermore cause transparent element14together with deposits, St, provided thereon to be displaced relative to lasers6,7,8thereby altering the distance or the inclination of transparent element14relative to the respective light exit surface10,11,12of lasers6,7,8. Such deformations may occur, for example, when the temple arm of the AR glasses is bent, for example due to a mismatch to the user who is wearing them. Furthermore, in the embodiments shown inFIGS.10,17,18,26,29,30, inFIG.31on the left, and inFIGS.32A,32B,38, even if transparent element14is correctly placed during fabrication, deformation of housing2may cause light reflected on transparent element14to directly re-enter the cavity of one of lasers6,7, or8, and in this case even with a significantly higher intensity than in the case where deposits, St, are present on transparent element14. Although such fluctuations in the emitted intensity will not always be perceptible to the naked eye, they may however be disruptive, even in the case of very fast electronic intensity control, and may interact with this intensity control in an undesirable way, since such intensity fluctuations usually comprise low-frequency components as caused by the deformation and higher-frequency components as caused by the mode hopping. Other than in assemblies of conventional optoelectronic devices which are usually arranged in an encapsulated environment, the deformations occurring in everyday use of AR glasses of the presently disclosed embodiments, for example, may already become significant when the distance of the transparent element changes by about half the wavelength of the light emitted by the lasers, since this may already suffice to change a positive interference of the back-reflected light into a negative interference and may impact respective other areas within the respective cavity of one of the lasers. Such undesirable changes in distance are thus in a range of only about 200 nm to 350 nm. The impact of such deformations is particularly crucial in embodiments in which the main direction of laser emission is substantially parallel to base plate4of housing2, which is true for presently disclosed embodiments, because in this case deformations of base plate4directly cause a change in the inclination or distance of transparent element14relative to the respective light exit surface10,11,12of lasers6,7,8. This effect is less pronounced in designs in which the main direction of laser emission is not substantially parallel but rather in particular perpendicular to the base plate of a housing, because in such embodiments a warp of the base plate would have less influence on the distance between the respective lasers and a respective exit window. In further prior art designs, a solid base plate can be made integrally with the side walls of the housing by milling, which, however, is complex in terms of manufacturing, especially for designs with inclined walls of the respective housing cap. At this point, another technical problem is encountered with designs that have extremely compact dimensions, as is the case with those presently disclosed, since the closer the light exit faces10,11,12of lasers6,7,8are to transparent element14, the higher might be the intensity of the light reflected back into the laser cavities by the aforementioned deposits. This intensity decreases with the square of the distance mentioned above and would require the largest possible value for L, which is in direct contradiction to a compact design. Here, L denotes the distance between the front side of pedestal5in the main emission direction of lasers6,7, or8and the edge of base plate4located in the main emission direction of lasers6,7, or8, and it is a crucial value for the following disclosure, since the greater the value of L, the lower will be the strength or mechanical stability of housing2without further measures. Furthermore, in the embodiments shown inFIGS.1,2,4,8,9,11,12,14,19,20,21,22,32C,32D, for example, pedestal5cannot be arranged arbitrarily close to the wall of housing cap3on which transparent element14is attached, because of the inclination of this wall, and must consequently be formed set back with respect thereto, which necessarily increases the length L compared to embodiments with substantially perpendicular walls of housing cap3. In order to avoid shading of the light emitted by lasers6,7,8, the distance L can be limited in length in further embodiments as well, as shown inFIGS.25and26, by way of example. In the designs as disclosed in WO 2020/004100 A1, for example, the path of the laser light is considerably prolonged by beam-deflecting components such as at least partially spectrally reflecting mirrors, and so is the distance for light reflected back into respective laser cavities, so that the intensity of back-reflected light will be considerably lower than in the presently disclosed embodiments. However, in the present embodiments, no beam deflecting components are provided within housing2defined by base plate4and housing cap3with transparent element14, in particular no at least partially reflective components such as mirrors or dichroic beam splitters or beam combiners, in particular for the sake of a compact housing design and very flexible use applications. The exemplary embodiments illustrated inFIGS.29and30are proposed as alternative embodiments in which the dichroic beam splitters or beam combiners38,39,40are located outside housing2, which however does not result in a prolongation of the path of light back-reflected by deposits St into the laser cavities as disclosed in WO 2020/004100 A1, for example. However, if light from lasers6,7,8is to be detected for metrological purposes, in particular for feedback control of the intensity of the light emitted by lasers6,7,8, it suffices to capture the light exiting from the rear side of lasers6,7,8and reflected on housing cap3or the light reflected on transparent element14, without having to accept significantly larger sizes of housing2. However, housing cap3or transparent element14are not used or referred to as mirrors or dichroic beam splitters or beam combiners in this case, since they are substantially not used to influence the guidance of the beam from lasers6,7,8exiting housing2. In order to provide a compact housing design that can be fabricated cost-efficiently from a manufacturing point of view, it would also be advantageous to use a housing cap3made by deep drawing, which should already provide sufficient mechanical strength when appropriately fastened to base plate4, as is the case with embodiments of multi-laser arrangements1presently disclosed. The inventors have found that the aforementioned distance L between the front side of pedestal5in the main emission direction of lasers6,7, or8and the edge of base plate4located in the main emission direction of lasers6,7or8, i.e. in the X direction, can have a crucial impact on this stability, since a deformation or bending of this area has a significant impact on the distance between light exit surface10,11,12of lasers6,7,8and transparent element14. InFIG.6this distance is denoted by L and the thickness of base plate4is denoted by W. The wording “thickness W of base plate4” relates to the respective parallel area of the upper and lower surfaces of base plate4at those locations where base plate4has no elevations on its upper side. In these embodiments, the thickness W of base plate4is preferably in a range from 0.1 to 1 mm and is particularly preferably in a range from 0.2 to 0.5 mm. In the embodiments shown inFIGS.10,17,18,23,24,25,26,29,30,31,32A, and32B, with walls extending essentially perpendicular to base plate4and accordingly with a transparent element14arranged perpendicular, the distance L was preferably approximately between 0.7 and 2 mm and especially preferred between 0.9 and 1.7 mm, since in these cases deposits are less likely to be feared than in embodiments with an inclined transparent element14, and the short distance L and the ratio V of length L to thickness W of the base plate discussed below resulted in very stable housings2. In these housing designs for the ratio V of length L to thickness W of the base plate, V=L/W for the preferred embodiments, a value of 3.4 to 4.5 was achieved, with smaller values of V providing greater stability of the housing. In general, however, values of V from 2 to 7 could be used for these embodiments. However, in the embodiments with an inclined transparent element14as illustrated inFIGS.1,2,4,8,9,11,12,14,19,20,21,22,FIG.31on the right, and inFIGS.32C,32D, a value of approximately 2 mm to 4 mm, preferably of 2.7 to 3 mm was used for distance L. The thickness W of the base. plate in these embodiments is also preferably in a range from 0.1 to 1 mm and is particularly preferably in a range from 0.2 to 0.5 mm. These values gave for the ratio V of the length L to the thickness of the base plate W, V=L/W, for the preferred embodiments a value of 6.6 to 13.5 In general, however, values for V of 4 to 20 could be used for these embodiments. The higher values of V were also able to provide very stable housings in these designs, since the inclination of the wall of housing cap3to which transparent element14is attached, as disclosed here, provided a further increased strength-increasing effect through housing cap3. In general, base plates4with a greater thickness would have led in each case to a more stable design of housing2, but it was surprising to see that even the thickness of base plate4of 0.2 to 0.5 mm used in the preferred embodiments was already able to provide sufficient stability in an extremely compact housing design. In the context of the present disclosure, it is furthermore assumed that in the preferred embodiments pedestal5rises above base plate4in a substantially cuboid shape with walls that extend vertically in the Z direction thereby imparting it additional stability against deformation or warp. These geometric relationships are also shown inFIG.6, by way of example. In the context of the present disclosure, base plate4is understood to be that housing component from which the electrical connection lines Z, and in particular Z6, Z7, and Z8emerge and where multi-laser arrangement1is usually joined to further external assemblies, which is a fundamental difference of the presently disclosed embodiments compared to vertically emitting arrangements. Generally, transparent element14has proven to be a very advantageous component that increases the strength of housing2. It allowed to considerably increase shear rigidity of housing2, in particular, when fixed on housing cap3by a gold solder A, in particular AuSn solder, or by a frame R. A preferred thickness Dt of the transparent element, see, e.g., the view inFIG.31on the left, was about 0.2 mm to 0.6 mm, preferably 0.25 mm or 0.5 mm. Simulations were performed in order to obtain a general understanding of the effect of external forces on housing2and thus to obtain a mechanically stable arrangement which is able to mitigate or even virtually eliminate the drawbacks of back-reflected light as described above, even with extremely compact designs that are also advantageous in terms of manufacturing techniques. These embodiments used for load testing by simulation, which can also be implemented accordingly in the other embodiments disclosed herein, used a deep-drawn housing cap3made of a deep-drawable nickel alloy, and a base plate3made of cold-rolled CRS1010 steel. A weld seam S as illustrated inFIG.9was created between housing cap3and base plate4, extending substantially over the entire contact surface between housing cap3and base plate4below a lateral projection As of housing cap3, which defines a welding flange, where the width of the lateral projection is about 0.2 to 0.5 mm. This provided a circumferential bond between housing cap3and base plate4, which was continually mechanically stable even under the conditions of the present test. FIG.44shows an exemplary perspective view of a base plate4with a pedestal5arranged thereon on which the mechanical load test was performed by simulation. During this load test, base plate4was fixed with portion B shown inFIG.45and delimited by dash-dotted lines, so that it could not deform in this portion B. In order to simulate effects of forces occurring in everyday operational use in the most appropriate way, a force as represented by the force vector Kf was introduced into base plate4with a thickness W of 0.25 mm, in the Z direction, as shown inFIG.45and also in the further load tests presently disclosed. As shown inFIG.45, the point of application of the force vector Kf was at a corner laterally of base plate4opposite portion B. The introduced force was of a magnitude of 1 N in all of the load tests presently disclosed. When the multi-laser arrangement is arranged on the temple arm of AR glasses41,41′ as shown inFIGS.33and43, portion B corresponds to a rear portion closer to the ear of a wearer of AR glasses41,41′, and the point at which the force vector Kf is applied corresponds to a portion of the temple arm of the respective AR glasses41,41′ that is more distant from the ear of the respective wearer of the AR glasses. In this way, typical mechanical loads occurring in everyday operation were reproduced. In a first test, no housing cap3was placed on base plate4, in order to better understand the general behavior of base plate4with a thickness of 0.25 mm. FIG.46shows the deformations resulting from the load test, which were in a range of up to a maximum of 1.9 mm in the area below force vector Kf. This result already clearly shows that base plate4per se, without further stabilizing measures, is not suitable on its own to provide the required stability. Thus, the combination of housing cap3and base plate4, especially with pedestal5arranged thereon, is of considerable importance for the overall resulting stability. FIG.47shows an embodiment of a base plate4with a housing cap3fixed thereon according to a presently disclosed multi-laser arrangement1in which the thickness of the base plate is again 0.25 mm and the thickness Wg of the material of housing cap3amounts to 0.15 mm. As in the load test described further below with reference toFIGS.49and50, pedestal5was fixed on base plate4in each case, in order to allow to identify the deformations of housing2of the multi-laser arrangement1as realistically as possible. FIG.48shows the results of the load test of the embodiment shown inFIG.47, with a base plate4and a housing cap3fixed thereon and a pedestal5, and it can be seen that the maximum deformation was only about 0.68 mm. Thus, with housing cap3and pedestal5, the deformation of base plate4was considerably reduced. FIG.49shows a further embodiment of a base plate4with a housing cap3fixed thereon and with a pedestal5joined to the base plate according to a presently disclosed multi-laser arrangement1. In this embodiment, housing cap3has a portion of the side walls in the form of a portion81that is offset laterally outwards. The height H of lateral portion81is approximately 0.5 mm and may range from 0.3 to 1 mm. The amount B by which portion81is offset outwards is approximately 0.4 mm and may range from 0.2 to 1 mm. In this embodiment mentioned above and shown inFIGS.49and50, the base plate has a thickness W of 0.1 mm, and the thickness Wg of the material of the housing cap is 0.5 mm. FIG.50shows the results of the load test by simulated predefined introduction of a force into the base plate for the further embodiment shown inFIG.49. Surprisingly, maximum deformation of the housing was only 0.23 mm. However, this deformation essentially only takes place outside the projection. The rest of the housing inside the laterally outwardly offset section81only deforms by less than 0.016 mm. Since the thickness of the base plate directly contributes to the height of housing2, it should consequently, as mentioned before, not be unnecessarily large, in view of a most compact design possible, but should rather be selected as small as possible. The embodiment described next shows a very advantageous configuration in which the housing is imparted considerable additional strength without, however, unnecessarily increasing its height. In this further preferred embodiment, base plate4, at least with its lateral edge, may extend at least partially or completely inside the laterally offset portion81and engage thereon from inside in a form-fitting manner. In this embodiment, weld seam S may then extend laterally between base plate4and portion81, in particular all along the inner circumference of portion81and the lateral edge Rs of base plate4. Given the above disclosure, a preferred embodiment resulting for multi-laser arrangement1includes:a deep-drawn housing cap3comprising or made of a deep-drawable material;a base plate3with a ratio V of L to W, V=L/W,from 2 to 7, preferably from 3.4 to 4.5 in the case of a transparent element14arranged perpendicular relative to base plate4, i.e. in the normal direction of base plate4; andfrom 4 to 20, preferably from 6 to 13.5, in the case of a transparent element14arranged with an inclination relative to base plate4, whereinthe angle of inclination of the wall of the housing cap on which transparent element14is arranged then ranges from 35° to 60°, preferably from 40° to 50°, most preferably from 43° to 48°, relative to the normal direction of the lower surface of the base plate. In this embodiment, transparent element14may advantageously be fixed to housing cap3by a gold solder A, in particular an AuSn solder, or by a frame R, in particular to increase shear strength. Advantageously, in particular in order to increase strength, housing cap3has a laterally outwardly offset portion81, which is in particular provided in the lower portion thereof, adjoining base plate4. The base plate4may extend at least partially or completely inside the laterally outwardly offset portion, at least with its lateral edge Rs, and can engage thereon from inside in a form-fitting manner. While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. LIST OF REFERENCE SYMBOLS 1Multi-laser arrangement, in particular RGB module2Housing3Housing cap4Base plate5Pedestal6First laser, emitting in the red spectral range of the visible spectrum7Second laser, emitting in the green spectral range of the visible spectrum8Third laser, emitting in the blue spectral range of the visible spectrum9Lower surface or underside of base plate410Light exit face of laser611Light exit face of laser712Light exit face of laser813Opening of housing cap314Transparent element15Fast Axis Collimation (FAC) lens16Plane-parallel substrate17Fiberboard18Fast Axis Collimation (FAC) lens19Monitor diode20Monitor diode21Monitor diode22Exit face of FAC lens23Carrier of monitor diodes19,20,2124Conductor on surface of carrier2325Conductor on surface of carrier2326Injection end of fiber2727Fiber28Fused glass29Fused glass30Opening of housing cap331Opening of housing cap332Opening of housing cap333Protective means for the glass of transparent element1434Portion laterally protruding beyond transparent element1435Beam collimator36Beam collimator37Beam collimator38Dichroic beam splitter or beam combiner39Dichroic beam splitter or beam combiner40Dichroic beam splitter or beam combiner41AR glasses41′ AR glasses42Optical assemblies43Projection device44Sensor45Sensor46Sensor47Exchangeable lens48Processor49Wireless transmitter module, in particular 5G module50Rechargeable battery51Safety means52Hot molded optical element53Hot molded optical element54Hot molded optical element55Circumferential annular flange56Annular circumferential recess or groove57Preformed, in particular biconvex optical element, preferably in the form of a spherical lens58Preformed, in particular biconvex optical element, preferably in the form of a spherical lens59Preformed, in particular biconvex optical element, preferably in the form of a spherical lens60Solder glass of a glass solder61Plano-convex optical element62Plano-convex optical element63Plano-convex optical element64Solder glass of a glass solder65Optical element, in particular preformed, in particular aspherical optical element66Front wall of housing cap367Portion of pedestal5facing the transparent element1468Fiber69Fiber70Male-type part of optical connector71as part of a releasable optical connection, in particular of a releasably mateable optical plug-in connection7171Releasably mateable optical plug-in connection72Female-type part of optical connector71as part of a releasable optical connection, in particular of a releasably mateable optical plug-in connection7173External optical fiber74External optical fiber75External optical fiber76Optional lens arrangement77Fiber bundle78Exit end of fiber bundle79Diffuser element80Region of mixed light from fibers73,74,7581Portion of housing cap3laterally offset outwardlyA Gold solder, in particular AuSn solderAs Lateral projection of housing cap3B Portion of base plate fixed for the stress testBa Width of near-edge gold solder layerBg Width of near-edge glass solder layerB6Bonding wireB7Bonding wireB8Bonding wireDt Thickness of transparent element14E6Depression in upper surface of pedestal5for form-fitting and in particular aligned accommodation of laser6E7Depression in upper surface of pedestal5for form-fitting and in particular aligned accommodation of laser7E8Depression in upper surface of pedestal5for form-fitting and in particular aligned accommodation of laser8G Glass solderH Height of lateral projection of housing cap3Ha Height of housing2of rectangular cross section shown inFIG.18, in which gold solder A was usedHg Height of housing2of rectangular cross section shown inFIG.17, in which glass solder G was usedHs Beam diameter in Z direction of light beams leaving the lasers6,7, or8in the respective main emission direction H6, H7, or H8H6to H8Main emission direction of lasers6,7, and8, respectivelyKf Force vector of force to be introduced during load testL Distance from the front side of pedestal5in the main emission direction of lasers6,7, or8to the edge of base plate4located in the main emission direction of lasers6,7, or8N Normal direction of lower surface9of base plate4Nt Normal direction of the surface of carrier23on which the monitor diodes19,20,21are arrangedNw Normal direction of the surface of the wall of housing cap3on which the transparent element14is arrangedOE6Countersunk surface of depression E6OE7Countersunk surface of depression E7OE8Countersunk surface of depression E8P Arrow in viewing direction to fiber end78of fiber bundle77R Frame carrying the transparent element14Rs Lateral edge of base plate4S Weld seam between housing cap3and base plate4T Blackening, in particular a paint or coating such as a black chrome coating or a zinc-nickel coating, in particular also electrolytic coatingW Thickness of base plate, in particular along distance LWg Thickness of the material of housing cap3Z Connection line, in particular electrical connection line to a laserZ6Connection line, in particular electrical connection line to laser6Z7Connection line, in particular electrical connection line to laser7Z8Connection line, in particular electrical connection line to laser8Z19Connection line to monitor diode19Z20Connection line to monitor diode20Z21Connection line to monitor diode21Ze Line direction of associated imaging device | 61,093 |
11862942 | DETAILED DESCRIPTION The following detailed description of example implementations refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. An indirect-time-of-flight (iToF) measurement system may include a structured light device (e.g., that includes an emitter array, such as VCSEL array; a lens; a DOE; and/or the like) for projecting dots onto a target (e.g., a screen, a face, a scene, and/or the like) to allow the iToF measurement system to measure the target. Typically, features of the DOE are formed along rectilinear axes of the DOE that are perpendicular to an optical axis of the lens and/or the DOE. Typically, a VCSEL array of the structured light device includes a plurality of emitters that conforms to an emitter pattern, which is positioned along an optical axis of the lens and/or the DOE of the structured light device. Typically, the emitter pattern is oriented parallel to an edge of a chip of the VCSEL, which is oriented parallel to one of the rectilinear axes of the DOE. This may produce a homogeneous dot projection on the target (e.g., many dots of the dot projection may be vertically or horizontally aligned), which may prevent the iToF measurement system from obtaining an accurate measurement of the target. Moreover, in some cases, the emitter pattern of the VCSEL array may be horizontally or vertically aligned parallel to an edge of a chip of the VCSEL array, which may allow crystal plane defects (e.g., that typically run vertically or horizontally along the chip) of the chip to easily propagate to sets of emitters of the emitter pattern. This may cause some emitters to fail and therefore negatively impact a performance of the VCSEL array. Some implementations described herein provide a VCSEL array that includes a plurality of emitters that conforms to an emitter pattern that is oriented at a non-zero angle (e.g., between 1 and 45 degrees, between 5 and 20 degrees, and/or between 9 and 13 degrees, among other examples) to a rectilinear axis of an associated DOE and/or to a reference edge of a chip of the VCSEL array (e.g., a semiconductor substrate of the VCSEL on which the plurality of emitters are formed). The emitter pattern may comprise one or more unit cells (e.g., that act as fundamental units of the emitter pattern) that may be arranged to form the emitter pattern (e.g., placed side-by-side in m rows and n columns, where m and n are greater than or equal to 1). Each unit cell, when the emitter pattern comprises two or more unit cells, may include a same number of emitters, and the two or more unit cells may be arranged to minimize an amount of misalignment between adjacent unit cells (e.g., in an x-direction and/or a y-direction). In some implementations, the DOE may generate a dot projection from light emitted by the plurality of emitters of the VCSEL array. The dot projection may comprise a plurality of tiles, wherein each tile comprises a plurality of dots that conforms to a dot pattern that corresponds to the emitter pattern (e.g., a dot of the dot pattern is respectively associated with an emitter of the emitter pattern). The DOE may be configured such that the plurality of tiles are arranged to minimize an amount of misalignment between adjacent tiles (e.g., in the x-direction and/or the y-direction). In this way, some implementations described herein allow a DOE to generate an aligned and/or consistently spaced dot projection from light produced by a VCSEL array with an emitter pattern with a non-zero tilt angle (e.g. in relation to a rectilinear axis of the DOE and/or to a reference edge of the VCSEL chip). Accordingly, the dot projection generated in some implementations described herein is more heterogeneous than that produced using a conventional VCSEL array without a non-zero tilt angle (e.g., few dots of the dot projection are vertically or horizontally aligned), which allows an iToF measurement system that includes the VCSEL array and/or the DOE described herein to obtain a more accurate measurement of a target. Moreover, by using an emitter pattern with a non-zero tilt angle (e.g. in relation to a rectilinear axis of the DOE and/or to a reference edge of the VCSEL chip), the emitter pattern is not horizontally or vertically aligned with a reference edge of a chip of the VCSEL array, which reduces a likelihood that crystal plane defects will propagate to sets of emitters of the emitter pattern. Accordingly, this prevents some emitters from failing and therefore improves a performance of the VCSEL array and/or improves a robustness of the VCSEL array. FIGS.1A-1Bare diagrams of an example implementation100described herein. As shown inFIG.1A, a structured light device102may include a VCSEL array104that includes a plurality of emitters106(e.g., in a chip of the VCSEL array104), a lens108, and/or a diffractive optical element (DOE)110(shown as a diffraction grating). The structured light device102may be configured to emit a dot projection112comprising a plurality of dots114. For example, the plurality of emitters106of the VCSEL array104may be configured to emit light, the lens108may be configured to collimate the light and/or direct the light to the DOE110, and the DOE110may be configured to generate the dot projection112across a scene (e.g., a target, an object, and/or the like). As shown inFIGS.1A and1B, the plurality of emitters106may conform to an emitter pattern116. As shown inFIGS.1A and1B, the emitter pattern116may be oriented at an angle to a rectilinear axis of the DOE110(e.g., shown inFIG.1Bas either the y- or z-axis) and/or to a reference edge118of the VCSEL chip (e.g., at a non-zero angle). The orientation of the emitter pattern116is further described herein. As shown inFIG.1A, the dot projection112may be a repeated optical copy of the emitter pattern116tiled together. The composition of the dot projection112is further described herein. As indicated above,FIGS.1A-1Bare provided as an example. Other examples may differ from what is described with regard toFIGS.1A-1B. FIG.2is a diagram of an example dot projection200associated with a conventional120-emitter VCSEL array (e.g., a 12×10 emitter hexagonal array) of a structured light device, wherein an emitter pattern of the conventional120-emitter VCSEL array has a zero-degree tilt angle (e.g., the emitter pattern is aligned with a rectilinear axis of a DOE of the structured light device and/or a reference edge of a chip of the VCSEL array). As shown inFIG.2, a first tile202of the example dot projection200(e.g., the darker dots of the example dot projection200) may be a first optical projection of the emitter pattern, and a second tile204of the example dot projection200(e.g., the lighter dots of the example dot projection200) may be a second optical projection of the emitter pattern. As shown inFIG.2, the first tile202of the example dot projection200may be tiled adjacent to the second tile204of the example dot projection200(e.g., projected next to each other to form a 1×2 tile pattern). As shown by line206and line208, respectively passing through a plurality of dots of the first tile202of the example dot projection200and a plurality of dots of the second tile204of the example dot projection, the first tile202and the second tile204of the example dot projection200are aligned (e.g., a spacing associated with the dots of the example dot projection200is uniform and/or consistent throughout the example dot projection200). Accordingly,FIG.2illustrates the ease of replicating an array when there is a zero tilt angle. As indicated above,FIG.2is provided as an example. Other examples may differ from what is described with regard toFIG.2. FIG.3is a diagram of an example dot projection300associated with a conventional240-emitter VCSEL array of a structured light device, wherein an emitter pattern302of the conventional240-emitter VCSEL array has an eleven degree tilt (e.g., the emitter pattern is oriented at eleven degrees to a rectilinear axis of a DOE of the conventional structured light device). As shown inFIG.3, the example dot projection300is a 3×3 optical projection of the emitter pattern302(e.g., the emitter pattern may be optically projected to form nine tiles, identified by dashed lines, arranged in a three row and three column tile pattern). However, because of the eleven degree tilt, dots in a middle tile of the example dot projection300are not aligned with dots in adjacent tiles of the middle tile. For example, as shown by line304, dots from tiles that are above and below the middle tile are not aligned with dots from the middle tile. As another example, as shown by line306, dots from tiles that are to the left and right of the middle tile are not aligned with dots from the middle tile. Moreover, as shown by arrows308, dots from an edge of the middle tile may not have a uniform and/or consistent spacing from dots of adjacent tiles. Accordingly, due to misalignment and spacing issues when using a conventional VCSEL array with a non-zero tilt angle, some implementations described herein provide a VCSEL array with an emitter pattern that has a non-zero tilt and that emits light that can be projected (e.g., by a lens and/or DOE) into an aligned and/or consistently spaced dot projection. Additionally, some implementations described herein provide a method for designing such a VCSEL array with an emitter pattern that has a non-zero tilt. As indicated above,FIG.3is provided as an example. Other examples may differ from what is described with regard toFIG.3. FIGS.4A-4Dare diagrams of an example implementation400related to designing an emitter pattern (e.g., the emitter pattern116shown inFIG.1) that has a tilt angle (e.g., oriented at a non-zero angle) for a VCSEL array (e.g., the VCSEL array104or another VCSEL array) described herein that can be used in a structured light device (e.g., the structured light device102that includes the lens108and/or the DOE110) to emit a dot projection (e.g., the example dot projection112) comprising a plurality of tiles, wherein dots of the dot projection are aligned and/or consistently spaced. In some implementations, a user device may be used to design the emitter pattern. In some implementations, the user device may include a communication device and/or a computing device. For example, the user device may include a wireless communication device, a mobile phone (e.g., a smart phone or a cell phone, among other examples), a laptop computer, a tablet computer, a handheld computer, a desktop computer, or a similar type of device. The user device may include a processor, such as a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or another type of processing component. The processor may be implemented in hardware, firmware, and/or a combination of hardware and software. The user device may include one or more processors capable of being programmed to perform a function. One or more memories, including a random-access memory (RAM), a read only memory (ROM), and/or another type of dynamic or static storage device (e.g., a flash memory, a magnetic memory, and/or an optical memory) may store information and/or instructions for use by the user device. The user device may include a memory (e.g., a non-transitory computer-readable medium) capable of storing instructions, that when executed, cause the processor to perform one or more processes and/or methods described herein. In some implementations, the user device may obtain one or more optical requirements (e.g., from a data structure, from information input by a user via a user interface of the user device, and/or the like) for a structured light device. For example, the optical system requirements may include information concerning a target dot projection (e.g., a target dot pattern of each tile that comprises the dot projection, a target number of dots of the dot projection, and/or the like), information concerning a target operating current (Iop), information concerning a target output optical power for the Top (Pop), information concerning a target range for a number of emitters of the VCSEL array, information concerning a target tilt angle range of an emitter pattern of the VCSEL, array information concerning a target chip size (e.g., an active area, one or more dimensions, and/or the like of a chip that includes the VCSEL array), information concerning a target FOV of the DOE (e.g., an angular size of an FOV), information concerning a target aspect ratio of the DOE (e.g., a number of rows and/or columns of an emitter pattern that the DOE optically projects), and/or the like. Accordingly, the user device may adjust, design, and/or the like, parameters associated with an emitter pattern for a VCSEL array, based on one or more of the optical requirements, to provide an optimal configuration of the emitter pattern for the VCSEL array. In some implementations, the user device may determine (e.g., based on one or more of the optical requirements) an emitter pattern for the VCSEL array, such as hexagonal emitter pattern402inFIG.4AFor example, the user device may determine the emitter pattern based on the information concerning the target dot projection, the information concerning the target range for the number of emitters of VCSEL array, the information concerning the target tilt angle of the emitter pattern of the VCSEL array, the information concerning the target chip size, the information concerning the target FOV, and/or the like. The emitter pattern may include a plurality of emitters. For example, the hexagonal emitter pattern402shown inFIG.4Aincludes seven emitters. As shown on the left side ofFIG.4A, the hexagonal emitter pattern402may have zero-degree tilt angle. As shown on the right side ofFIG.4A, the hexagonal emitter pattern402may have tilt angle α (shown inFIG.4Aas 11 degrees, but α may be any non-zero angle within a range, such as 9 to 13 degrees). The user device may determine the tilt angle based on the information concerning the target angle range specified by the optical requirements. As also shown inFIG.4A, positions of emitters in the hexagonal emitter pattern402(e.g., when the hexagonal emitter pattern402has a zero-degree tilt angle or an a tilt angle) may be expressed by a and b vectors for any pitch and/or any tilt angle α. In some implementations, the emitter pattern may be a hexagonal emitter pattern that includes one or more instances of the hexagonal emitter pattern402arranged next to each other (e.g. wherein emitters of the one or more instances of the hexagonal emitter pattern402are aligned and consistently spaced). Such a hexagonal emitter pattern may provide a compact VCSEL array while maintaining a maximum spacing between emitters of the hexagonal emitter pattern. Additionally, or alternatively, the emitter pattern may conform to another pattern, such as a square pattern, a rectangular pattern, an octagonal pattern, and/or the like. In some implementations, the user device may determine a unit cell of emitters to be able to determine an emitter pattern of a VCSEL array. A unit cell may include a plurality of emitters wherein placement of an emitter, of the plurality of emitters, in a layout of the unit cell in relation to each of the other emitters, of the plurality of emitters, may be expressed as a combination of a first vector and a second vector. For example,FIG.4Bshows an emitter pattern404of a210-emitter VCSEL array of a structured light device, wherein the emitter pattern404is a hexagonal emitter pattern and has an eleven degree tilt. A magnified view of a portion of the emitter pattern404inFIG.4Bshows a unit cell406. The unit cell406comprises seventeen emitters within a rectangular bounding box. As shown inFIG.4B, placement of an emitter in a layout of the unit cell406in relation to another emitter in the layout of the unit cell may be expressed by a combination of an a vector and a b vector (e.g., vectors representing shortest paths between dots of the emitter pattern404). In some implementations, the user device may determine bounds of a unit cell by identifying a combination of the first vector and the second vector that expresses a difference in placement of emitters that have a same x-coordinate or a same y-coordinate (or some other similar coordinate). For example, as shown inFIG.4B, the user device may determine the borders of the unit cell406that can be expressed by a difference in placement of emitters that have a same x-coordinate (hereinafter referred to as dy), which is represented by 3b×1a (e.g., a total distance in they-direction represented by 3 times the b vector and 1 times the a vector), and a difference in placement of emitters that have a same y-coordinate (hereinafter referred to as dr), which is represented to 1b×5a (e.g., a total distance in the x-direction represented by 1 times the b vector and 5 times the a vector). As another example, the user device may determine borders of a unit cell408using a similar process, wherein the borders of the unit cell408can be expressed as 3b×5a (e.g., a total distance in they-direction represented by 3 times the b vector and a total distance in the x-direction represented by 5 times the a vector). In some implementations, the user device may determine an emitter pattern of a VCSEL array based on determining a unit cell. For example, the user device may arrange two or more unit cells (e.g., copies of the same unit cell, such that each copy has the same number of emitters, the same layout, the same spacing, and/or the like) to form the emitter pattern so that the unit cells are adjacent to each other (e.g., in rows, columns, and/or the like, such that the copies of the unit cell are placed next to each other, consistently spaced from one another, do not overlap each other, and/or the like). Accordingly, a placement of an emitter in a first unit cell, of the two or more unit cells that form the emitter pattern, in relation to a corresponding emitter of a second unit cell, of the two or more unit cells, may be expressed as a combination of dx and/or dy. In some implementations an alignment error may be associated with two adjacent unit cells of the emitter pattern. For example, as shown inFIG.4B, Δx may represent an amount of misalignment between adjacent unit cells406along the y-axis (e.g., an amount of error associated with dy) and/or Δy may represent an amount of misalignment between adjacent unit cells406along the x-axis (e.g., an amount of error associated with dx). In other words, Δx and Δy represent unit cell placement errors when the sums of a and b vectors don't add up to an exact dy or dx shift for a given tilt angle. In some implementations, the user device may determine a unit cell and/or an emitter pattern such that the amount of misalignment between adjacent unit cells of the emitter pattern is minimized. For example, the user device may determine a unit cell and/or an emitter pattern such that Δx satisfies (e.g., is less than or equal to) any-axis misalignment threshold and/or Δy satisfies (e.g., is less than or equal to) an x-axis misalignment threshold. In some implementations, the x-axis misalignment threshold and/or the y-axis misalignment threshold may be 5 nanometers (nm), 10 nm, 20 nm, 50 nm, and/or the like. In some implementations, the user device may adjust (e.g., in association with determining the unit cell and/or the emitter pattern) the tilt angle of the emitter pattern to minimize the amount of misalignment between adjacent unit cells. For example, the user device may adjust a target tilt angle of 11 degrees (e.g., indicated by the optical requirements obtained by the user device) to a tilt angle of 10.89 degrees to yield a lower amount of misalignment than the amount of misalignment achieved with 11 degrees. In some implementations, the user device may determine a number of unit cells to arrange along the x-axis and/or the y-axis to form the emitter pattern such that the emitter pattern has an aspect ratio, a number of emitters, and/or the like that satisfy the optical requirements. For example,FIG.4Cincludes a table410that identifies a number of emitters for an emitter pattern based on numbers of multiples (e.g., m columns and n rows) of a unit cell (e.g., with bounds defined by dx and dy) that includes 14 emitters. Stated differently, table410provides discrete number solutions for a number of emitters of an emitter pattern based on number of unit cells forming the emitter pattern, where dx and dy represent a size of the unit cell (e.g., in microns). Shaded solutions correspond to a number of emitters falling within the range of 172 emitters to 257 emitters, which may be an optimal range of emitters for a particular implementation. In some implementations, the user device selects a number of emitters from the discrete solutions of table410based on aspect ratios of the discrete solutions and/or an aspect ratio of an active area size (e.g., a chip size) of the VCSEL array. For example, the optical requirements may indicate an active area size (e.g., a chip size, represented by X×Y) in a range of approximately 500 microns by 500 microns, which corresponds to an aspect ratio (X/Y) of approximately one. Thus, in such an example and as indicated by the oval in FIG.4C, the user device may select a discrete solution for m=3 and n=5, which yields210emitters (e.g., 3×5×14 emitters) and an active area of X=439.9265 microns and Y=423.31948 microns (e.g., such that the aspect ratio X/Y is approximately one). As shown in Table410, the other shaded solutions yield an active area outside of the range provided by the optical requirements (e.g., X or Y ranges greater than 500 microns). Accordingly, other numbers of emitters and/or active area sizes may lead to vertical and/or horizontal misalignment, gaps of projected dots, and/or overlap of projected dots. In this way, the user device may determine an optimal emitter pattern associated with a target tilt angle that includes a total number of emitters that are within a target range for a number of emitters (e.g., the total number of emitters of the emitter pattern is greater than or equal to a minimum number of emitters and less than or equal to a maximum number of emitters), that conforms to a target aspect ratio, and/or the like, of the structured light device. In some implementations, the user device may adjust the aspect ratio of the emitter pattern (e.g., an X×Y active area of a VCSEL chip) to address an optical requirement of a lens and/or a DOE of the structured light device. For example, the DOE may have an FOV of 60×78 degrees for a dot projection comprising an aspect ratio of 5×7 tiles and the user device may determine that an optimal chip aspect ratio equals (60/5)/(78/7), or approximately 1.08. In some implementations, the user device may adjust pitch in the emitter pattern and/or may scale (e.g., stretch or shrink), in the x and/or y direction, the emitter pattern to adjust the emitter pattern to comply with the optimal chip aspect ratio.FIG.4Dincludes a table412that demonstrates an example of the user device adjusting pitch (e.g., with an original emitter pitch of 32 microns) in the emitter pattern and stretching the emitter pattern (e.g., with an original active area size of 439.9265 microns×423.31948 microns and an original aspect ratio of 1.0392305) to a target active area size (e.g., 422 microns×380 microns) and a target aspect ratio (e.g., approximately 1.11). In this example, the user device may adjust the pitch of the emitter pattern from 32 microns to 28.7 microns (e.g., to uniformly shrink the unit cells that form the emitter pattern), which may cause the target active area size to reduce to 394.9165 microns×380.0086 microns. The user device may then stretch the emitter pattern in the x-direction from 394.9165 microns to 422 microns, to obtain the target active area size (e.g., 422 microns×380 microns) and the target aspect ratio (e.g., approximately 1.11). As further shown in table412, this may result in a pitch in the emitter pattern that differs in the x and y directions. (e.g., the pitch in the x direction has one value and the pitch in the y direction has a different value). For example, the length of the a vector may be changed from 28.726 microns to 30.627 microns, and the length of the b vector may be changed from 28.726 microns to 28.941 microns. As additionally shown, the tilt angle associated with the emitter pattern may be adjusted, from 11 degrees to 10.955 degrees, as a result of adjusting the pitch and/or stretching the emitter pattern. In this way, the user device may iteratively adjust one or more parameters associated with an emitter pattern for a VCSEL array to design an optical emitter pattern for a lens and/or a DOE of a structured light device to emit a dot projection comprising a plurality of tiles, wherein corresponding dots of each tile of the dot projection are aligned and/or consistently spaced. As indicated above,FIGS.4A-4Dare provided as an example. Other examples may differ from what is described with regard toFIGS.4A-4D. FIG.5is a diagram of an example dot projection500associated with an exemplary210-emitter VCSEL array of a structured light device, wherein an emitter pattern502(e.g., an optimal emitter pattern that was designed using the user device, as described herein in relation toFIGS.4A-4D) of the exemplary210-emitter VCSEL array has an 11-degree tilt angle. As shown inFIG.5, the example dot projection500is a 3×3 optical projection of the emitter pattern502(e.g., the emitter pattern may be optically projected to form nine tiles, approximately identified by dashed lines, arranged in a three row and three column tile pattern). Accordingly, each tile of the example dot projection500may include a plurality of dots that conforms to a dot pattern (e.g., that corresponds to the emitter pattern502), wherein each dot of the dot pattern is respectively associated with an emitter of the emitter pattern502. In some implementations, when a placement of a first emitter in the emitter pattern502in relation to a second emitter in the emitter pattern502can be expressed as a combination of vectors (e.g., the a and b vectors described herein), a placement of a first dot in the dot pattern (e.g., that corresponds to the first emitter) in relation to a second dot in the dot pattern (e.g., that corresponds to the second emitter) can be expressed as a combination of the same vectors (e.g., the a and b vectors multiplied by respective constants associated with the example dot projection500). As further shown inFIG.5, each tile of the example dot projection500comprises multiple repetitions of a unit cell504that comprises the emitter pattern502. For example, a middle tile of the example dot projection500comprises five rows and three columns of repetitions of the unit cell504(e.g., based on a 5×3 design of the emitter pattern502). As further shown inFIG.5, the tiles of the example dot projection500do not overlap one another and are placed adjacent one another to form a seamless dot pattern. As indicated above,FIG.5is provided as an example. Other examples may differ from what is described with regard toFIG.5 FIG.6is a diagram of an example dot projection600associated with an exemplary210-emitter VCSEL array of a structured light device, wherein an emitter pattern (e.g., an optimal emitter pattern, not shown, that was designed using the user device, as described herein in relation toFIGS.4A-4D) of the210-emitter VCSEL array is a hexagonal emitter pattern and has an eleven degree tilt As shown inFIG.6, the example dot projection600is a 1×2 optical projection of the emitter pattern (e.g., the emitter pattern may be optically projected to form two tiles arranged in a row). As further shown inFIG.6, a first tile602of the example dot projection600(e.g., that includes the light dots of the example dot projection600) may be a first optical projection of the emitter pattern, and a second tile604of the example dot projection600(e.g., that includes the dark dots of the example dot projection600) may be a second optical projection of the emitter pattern. For example, a DOE of the structured light device may perform an optical translation operation of the emitter pattern along an axis (e.g., the x-axis shown inFIG.6) to cause the first tile602of the example dot projection600to be projected next to the second tile604of the example dot projection600along the axis. As further shown inFIG.6, in such an example, a dot606-1of the first tile602may have a same y-coordinate as a corresponding dot606-2of the second tile604, a dot608-1of the first tile602may have a same y-coordinate as a corresponding dot608-2of the second tile604, and so on. As another example, the DOE may perform an optical translation operation of the emitter pattern along a different axis (e.g., they-axis). In such an example, a dot of the first tile602may have a same x-coordinate as a corresponding dot in the second tile604. Additionally, or alternatively, the DOE may perform multiple optical translation operations of the emitter pattern along the x-axis, the y-axis, and/or another axis. For example, the DOE may perform an optical translation operation of the emitter pattern to generate one or more tiles (e.g., wherein each tile conforms to a dot pattern that is an optical projection of the emitter pattern) that are tiled adjacent each other to form a dot projection. In some implementations, the lens and/or the DOE may be configured to generate a dot projection comprising a plurality of tiles, such that an amount of misalignment between adjacent tiles of the dot projection is minimized. For example, the DOE may cause the plurality of tiles to be arranged to cause a measurement of tile misalignment (e.g., in the x-direction, the y-direction, and/or the like) associated with two adjacent tiles, of the plurality of tiles, to satisfy (e.g., be less than or equal to) a tile misalignment threshold. In some implementations, the tile misalignment threshold may be 1 μm, 3 μm, 10 μm, 20 μm, 50 μm, 100 μm and/or the like. In this way, the DOE may be configured to ensure that dots of the dot projection are aligned and/or consistently spaced. For example, as shown inFIG.6, a line610that connects dot608-of the first tile602and dot606-2of the second tile604passes through other dots of the first tile602, which indicates that the first tile602and the second tile604are well-aligned (e.g., a measurement of tile misalignment between the first tile602and the second tile604satisfies the tile misalignment threshold). As indicated above,FIG.6is provided as an example. Other examples may differ from what is described with regard toFIG.6. The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementations. Furthermore, any of the implementations described herein may be combined unless the foregoing disclosure expressly provides a reason that one or more implementations may not be combined. As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, etc., depending on the context. Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim in combination with every other claim in the claim set. No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Furthermore, as used herein, the term “set” is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.), and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”). Further, spatially relative terms, such as “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the apparatus, device, and/or element in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. | 34,191 |
11862943 | EMBODIMENTS FOR CARRYING OUT THE INVENTION A. Embodiment: FIG.1is a partial sectional view showing a schematic configuration of a spark plug100as an embodiment of the present disclosure. InFIG.1, an outward appearance of the spark plug100is illustrated on a left side of the drawing with an axis CA as an axial center of the spark plug100being a boundary, and a cross-sectional shape of the spark plug100is illustrated on a right side of the drawing. In the following description, a lower side ofFIG.1along the axis CA (a side on which an after-mentioned ground electrode40is provided) is called a top end side (or a tip end side), an upper side ofFIG.1(a side on which an after-mentioned metal terminal50is provided) is called a rear end side, and a direction along the axis CA is called an axis direction AD. InFIG.1, for convenience in description, an engine head90to which the spark plug100is connected is illustrated her a broken line. The spark plug100has an insulator10, a center electrode20, a metal shell30, the ground electrode40and the metal terminal50. The axis CA of the spark plug100is aligned with each axis CA of members of the insulator10, the center electrode20, the metal shell30and the metal terminal50. The insulator10has a substantially tubular outward appearance having a penetration hole11formed along the axis direction AD. A part of the center electrode20is accommodated at a top end side in the penetration hole11, whereas a part of the metal terminal50is accommodated at a rear end side in the penetration hole11. Therefore, the insulator10supports the center electrode20in the penetration hole11. Approximately half of a top end side of the insulator10is accommodated in an axial hole38of the after-mentioned metal shell30, and approximately half of a rear end side of the insulator10is exposed from the axial hole38. The insulator10is made of insulating glass formed by burning (or firing) ceramic material such as alumina. The insulator10has a large diameter portion14, a holding portion15, a small diameter portion16and a step portion17. The large diameter portion14is located at the rear end side of the insulator10in the axis direction AD. A diameter of the penetration hole11at the large diameter portion14is formed substantially constant. The holding portion15is formed at a top end side of the large diameter portion14so that its outside diameter is smaller toward the top end side along the axis direction AD. The small diameter portion16is located at the top end side in the axis direction AD with respect to the large diameter portion14. A diameter of the penetration hole11at the small diameter portion16is smaller than the diameter of the penetration hole11at the large diameter portion14. The penetration hole11at the small diameter portion16accommodates therein a part of a leg portion21of the after-mentioned center electrode20. FIG.2is an enlarged sectional view schematically showing the step portion17, a brim portion22and their vicinities.FIG.2shows a cross section including the axis CA. The step portion17is located between the large diameter portion14and the small diameter portion16in the axis direction AD, and connects the large diameter portion14and the small diameter portion16. The step portion17of the present embodiment is formed so that the diameter of the penetration hole11is smaller toward the top end side along the axis direction AD. In other words, the step portion17is formed so as to protrude or bulge inwards in a radial direction in the penetration hole11. The step portion17supports a connecting portion24of the center electrode20. The center electrode20shown inFIGS.1and2is a rod-shaped electrode extending in the axis direction AD. The center electrode20is supported in the penetration hole11of the insulator10. The center electrode has the leg portion21, the brim portion22and the connecting portion24. As illustrated inFIG.1, the leg portion21is formed so as to extend in the axis direction AD, and a part of the leg portion21is exposed from the penetration hole11. A noble metal chip made of e.g. an iridium alloy etc. could be joined to an end portion of a top end side of the leg portion21. As illustrated inFIG.2, the brim portion22is located at the rear end. side with respect to the leg portion21, and is formed so as to protrude outwards in the radial direction with respect to the leg portion21. In other words, the brim portion22is formed at an end portion of a rear end side of the center electrode20so as to protrude or bulge outwards in the radial direction. In the present embodiment, an outside diameter of the brim portion22is formed substantially constant. The connecting portion24connects the leg portion21and the brim portion22. The connecting portion24abuts on the step portion17of the insulator10. With this, positioning of the center electrode20in the penetration hole11of the insulator10is made. The connecting portion24of the present embodiment has a tapered shape whose outside diameter is gradually reduced toward the top end side. The center electrode20of the present embodiment is formed with a core25, which is excellent in thermal conductivity, being embedded inside an electrode member26. In the present embodiment, the core25is made of an alloy containing copper as a main component. The electrode member26is made of a nickel alloy containing nickel as a main component. As illustrated inFIG.1, a part of the center electrode20is inserted into the penetration hole11of the insulator10at the top end side of the penetration hole11, and a part of the metal terminal50is inserted into the penetration hole11of the insulator10at the rear end side of the penetration hole11. In the penetration hole11of the insulator10, a top end side seal member61, a resistor62and a rear end side seal member63are disposed in an order from the top end side toward the rear end side between the center electrode20and the metal terminal50. Therefore, the center electrode20is electrically connected to the metal terminal50at the rear end side of the center electrode20through the top end side seal member61, the resistor62and the rear end side seal member63. The resistor62is made of ceramic powder, conducting material, glass and adhesive as materials. The resistor62functions as an electric resistance between the metal terminal50and the center electrode20, thereby suppressing an occurrence of noise when spark discharge occurs. The top end side seal member61and the rear end side seal member63are each made of conductive glass powder as material. In the present embodiment, the top end side seal member61and the rear end side seal member63are each made of mixed powder of copper powder and calcium borosilicate glass powder as materials. The top end side seal member61contacts the brim portion22, the insulator10and the resistor62, and fixes these members to each other. The rear end side seal member63contacts the resistor62, the insulator10and the metal terminal50, and fixes these members. As illustrated inFIG.1, the metal shell30has a substantially tubular outward appearance having the axial hole38formed along the axis direction AD, and supports the insulator10in the axial hole38. More specifically, the metal shell30supports the insulator10by surrounding a body part of the insulator10from a part of the large diameter portion14to the small diameter portion16. The metal shell30is made of e.g. low-carbon steel, and is subjected to plating treatment such as nickel plating or zinc plating as a whole. The metal shell30has a tool engagement portion31, a male thread portion32, a seat portion33, a protruding portion34, a caulking portion35and a compressive deformation portion36. The tool engagement portion31is engaged with a tool (not shown) when connecting the spark plug100to the engine head90. The male thread portion32has threads on an outer peripheral surface of a top end portion of the metal shell30, and is screwed into a female thread portion93of the engine head90. The seat portion33is located so as to continue to a rear end side of the male thread portion32, and is formed into a brim shape. A ring-shaped gasket65formed by folding a plate or a sheet is inserted and fitted between the seat portion33and the engine head90. The protruding portion34is formed on an inner peripheral surface of the male thread portion32so as to protrude inwards in the radial direction. The holding portion15of the insulator10abuts on the protruding portion34from the rear end side. Therefore, the protruding portion34supports the insulator10inserted into the axial hole38. A ring-shaped plate packing (or a ring-shaped sheet packing) (not shown) is provided between the protruding portion34and the holding portion15. The caulking portion35is formed so that a thickness at the rear end. side with respect to the tool engagement portion31is thinner. The compressive deformation portion36is formed so that a thickness between the tool engagement portion31and the seat portion33is thinner. Annular ring members66and67are interposed between the axial hole38of the metal shell and an outer peripheral surface of the large diameter portion14of the insulator10from the tool engagement portion31to the caulking portion35in the axis direction AD, and a space between these ring members66and67is filled with powder of talc69. As described later, the metal shell30is fixed to the insulator10by caulking the caulking portion35. The ground electrode40is made of a bent bar-shaped metal member. Like the center electrode20, the ground electrode40is made of a nickel alloy containing nickel as a main component. One end of the ground electrode40is fixed to a top end surface37of the metal shell30, and the other end of the ground electrode40is bent or curved so as to face a top end portion (or a tip) of the center electrode20. The ground electrode40is provided, at a portion thereof that faces the tip of the center electrode20, with an electrode chip42. A gap G1for the spark discharge is formed between the electrode chip42and the tip of the center electrode20. The gap G1is also called a discharge gap or a spark gap. The metal terminal50is provided at an end portion of a rear end side of the spark plug100. A top end side of the metal terminal50is accommodated in the penetration hole11of the insulator10, and a rear end side of the metal terminal50is exposed from the penetration hole11. A high-tension cable (not shown) is connected to the metal terminal50, and high voltage is applied to the metal terminal50. The spark discharge occurs at the gap G1by this high voltage application. The spark discharge occurring at the gap G1ignites air-fuel mixture in a combustion chamber95. In the present embodiment, the top end side seal member61corresponds to a seal member in the present disclosure. The top end side (or the tip end side) corresponds to an axis direction top end side (or an axis direction tip end side) in the present disclosure, and the rear end side corresponds to an axis direction rear end side in the present disclosure. A method of manufacturing the spark plug100will be described below. First, the center electrode20is inserted into the penetration hole11of the insulator10from the rear end side. Subsequently, the penetration hole11is filled with the material powder of the top end side seal member61from the rear end side, and the material powder of the top end side seal member61is compressed from the rear end side (hereinafter, also referred to as “seal member filling process”). After that, the penetration hole11is filled with the material of the resistor62from the rear end side, and the material of the resistor62is compressed from the rear end side. Further, the penetration hole11is filled with the material powder of the rear end side seal member63from the rear end side, and the material powder of the rear end side seal member63is compressed from the rear end side. Each compression of the above could be performed, for instance, by inserting a rod-shaped jig (or a rod-shaped tool) into the penetration hole11. Afterwards, an end portion of the top end side of the metal terminal50is inserted into the penetration hole11, and compression is performed by applying a predetermined pressure from the metal terminal50side while heating the insulator10as a whole (hereinafter, also referred to as “heating compression process”). Each material filling the penetration hole11is compressed and burned by the heating compression process. With this, the top end side seal member61, the resistor62and the rear end side seal member63are formed in the penetration hole11. In this manner, the center electrode is fixed to the insulator10. Further, the insulator10to which the center electrode20has been fixed is inserted into the axial hole38of the metal shell30from the rear end side. Subsequently, by caulking the caulking portion35of the metal shell30, the metal shell30and the insulator10are fixed together. At this time, by pressing the caulking portion35of the metal shell30to the top end side so as to fold the caulking portion35inwards in the radial direction, the compressive deformation portion36is compressed and deformed. By the compressive deformation of the compressive deformation portion36, the insulator10is pressed toward the top end side in the metal shell30through the ring members66and67and the talc69. In this manner, the spark plug100is completed. As illustrated inFIG.2, the center electrode20of the present embodiment does not have, at a rear end side thereof with respect to the brim portion22, a portion whose diameter is reduced more than the brim portion22. In the present embodiment, “does not have the portion whose diameter is reduced” means that when a maximum value of a radius of the brim portion22on the cross section including the axis CA is D1and a minimum value of the radius of the brim portion22on the cross section including the axis CA is D2, in a case where the maximum value D1of the radius of the brim portion22is 100%, a difference from the minimum value D2of the radius of the brim portion22is within 6%. That is, the center electrode20of the present embodiment satisfies the following expression (1). (D1-D2)/D1≤0.06 expression (1) FIG.3is a schematic diagram for explaining a center29of gravity of the center electrode20.FIG.3schematically illustrates a structure of an outward appearance of the center electrode20viewed from a direction perpendicular to the axis CA. InFIG.3, for convenience in description, the axis CA is shown by a dashed line, and the center29of gravity of the center electrode20, located on the axis CA, is illustrated. In the present embodiment, the center29of gravity is positioned at a top end side in the axis direction AD with respect to the brim portion22and the connecting portion24. Here, regarding the position of the center29of gravity, when a string is tied to the leg portion21of the center electrode20and the center electrode20is strung up or suspended from a vertically upper direction by this string, the position of the center29of gravity can be determined from a position of the string in the axis direction AD when the axis CA balances parallel with a horizontal direction. When a size (a length) along the axis direction AD of the center electrode20on the cross section including the axis CA is L1and a size (a length) along the axis direction AD from a boundary28between the connecting portion24and the leg portion21to the center29of gravity of the center electrode20is L2, the center electrode20of the present embodiment satisfies the following expression (2). L2/L1≤0.30 expression (2) In the present embodiment, the boundary28between the connecting portion24and the leg portion21means a boundary between a top end of the connecting portion24and a rear end of the leg portion21. In a case of a structure in which the connecting portion24and the leg portion21are connected in a curved shape, the boundary28corresponds to a point (a virtual point) of intersection of a line obtained by extending the connecting portion24and a line obtained by extending the leg portion21on the cross section including the axis CA. The length L1in the above expression (2) corresponds to an overall length along the axis direction AD of the center electrode20. Further, satisfaction of the expression (2) is equivalent to the fact that when the length L1along the axis direction AD of the center electrode20is 100%, the length L2along the axis direction AD from the boundary28to the center29of gravity is within 30%. The center electrode20of the present embodiment satisfies the above expression (2), thereby preventing the position of the center29of gravity with respect to a position of the connecting portion24from being excessively separated toward the top end side in the axis direction AD. Here, as illustrated inFIG.2, the center electrode20is supported with the connecting portion24abutting on the step portion17of the insulator and fixed to the insulator10by the top end side seal member61filling the penetration hole11and contacting the brim portion22and the insulator10. Besides, as described above, the center electrode20of the present embodiment does not have, at the rear end side thereof with respect to the brim portion22, the portion whose diameter is reduced more than the brim portion22. That is, the above expression (1) is satisfied. Because of this, as compared with a structure having, at the rear end side thereof with respect to the brim portion22, the portion whose diameter is reduced more than the brim portion22, i.e. a spark plug not satisfying the above expression (1), a surface area, which contacts the top end side seal member61, of the brim portion22becomes small. Therefore, in a case of a structure in which the center29of gravity of the center electrode20is excessively separated from forming positions of the connecting portion24and the brim portion22toward the top end side, when the spark plug100is used with the spark plug100connected to the engine head90as illustrated inFIG.1, since a distance from the center29of gravity to the brim portion22is long, the brim portion22greatly swings or vibrates due to vibrations of the engine etc.. As a consequence, there is a risk that the top end side seal member61will be deformed then looseness of the center electrode20will occur. However, according to the spark plug100of the present embodiment, since the above expression (2) is satisfied, it is possible to prevent the position of the center29of gravity of the center electrode20from being located at an excessively top end side. This suppresses the excessive swing or vibration of the brim portion22caused by the vibrations of the engine etc.. As a result, the occurrence of the looseness of the center electrode20can be suppressed. A value of L2/L1is preferably 0.30 or less, more preferably 0.27 or less, and still more preferably 0.25 or less, in terms of suppressing the occurrence of the looseness of the center electrode20. When the value of L2/L1is 0.25 or less, since the position of the center29of gravity of the center electrode20can be brought closer to the positions of the connecting portion24and the top end side seal member61, the occurrence of the looseness of the center electrode20can be further suppressed. Further, by a method(s) of (i) as material constituting the brim portion22, a substance having a higher specific gravity than that of material constituting the leg portion21is used, (ii) the size (the length) of the brim portion22is set to be large in the axis direction AD and/or (iii) the size of the brim portion22is set to be large in the radial direction, the center29of gravity is positioned at a further rear end side, then the value of L2/L1can be smaller. However, if the brim portion22is formed as a separate member, the number of manufacturing processes is increased. Also, if the size of the brim portion22is set to be large, as a drawback, an electric capacity is increased. Therefore, in terms of reducing the number of manufacturing processes and suppressing the increase in the electric capacity, the value of L2/L1is preferably 0 or more, more preferably or more, and still more preferably 0.2 or more. In terms of suppressing the occurrence of the looseness of the center electrode20and suppressing the increase in the electric capacity, the value of L2/L1could be, for instance, 0.2 or more and 0.27 or less. Here, in the present application, in a case where the center29of gravity is positioned at a rear end side along the axis direction AD with respect to the boundary28between the connecting portion24and the leg portion21, a value of L2becomes a negative value. As illustrated inFIG.3, the size (the length) L1of the center electrode20of the present embodiment may be, for instance, about 10 mm to 30 mm. Further, a size (a length) L3along the axis direction AD of the brim portion22of the center electrode20of the present embodiment may be, for instance, about 1.5 mm to 3.0 mm. When the length L3is formed to be relatively small, since the increase in the electric capacity can be suppressed, it is possible to suppress exhaustion of the center electrode20. A method of setting the value of L2/L1to 0.30 or less is not particularly limited, but the following method can be raised as examples. For instance, at least a part of the brim portion22is formed of material having a higher specific gravity than that of material constituting the center electrode20. According to this method, since a change in outer dimensions of the center electrode20does not occur, it is possible to suppress an occurrence of a design change of the other constituent members of the spark plug100other than the center electrode20. As other methods, for instance, sizes (lengths) along the axis direction AD of the brim portion22and/or the connecting portion24are set to large, or sizes along the radial direction of the brim portion22and/or the connecting portion24are set to large. According to the spark plug100of the present embodiment described above, since the above expression (2) is satisfied, in the center electrode20satisfying the above expression (1), it is possible to prevent the position of the center29of gravity of the center electrode20from being located at an excessively top end side. Therefore, since the position of the center29of gravity of the center electrode20can be prevented from being excessively separated from the position of the top end side seal member61fixing the center electrode20and the insulator10, it is possible to suppress the occurrence of the looseness of the center electrode20caused by the vibrations of the engine etc.. Accordingly, in the spark plug100having the center electrode20satisfying the above expression (1) and not having, at the rear end side thereof with respect to the brim portion22, the portion whose diameter is reduced more than the brim portion22, it is possible to suppress an occurrence of a crack around the boundary28between the connecting portion24and the leg portion21of the center electrode20. Hence, degradation in performance of the spark plug100having the center electrode20not having, at the rear end side thereof with respect to the brim portion22, the portion whose diameter is reduced more than the brim portion22can be suppressed. Further, since the above expression (1) is satisfied, i.e. the center electrode20does not have, at the rear end side thereof with respect to the brim portion22, the portion whose diameter is reduced more than the brim portion22, the length L3along the axis direction AD of the brim portion22can be small. This can suppress the increase in the electric capacity, thereby suppressing the exhaustion of the center electrode20. Therefore, according to the spark plug100of the present embodiment, since the above expression (1) is satisfied and the above expression (2) is satisfied, it is possible to suppress the occurrence of the looseness of the center electrode20while suppressing the increase in the electric capacity. B. Example The present invention will be further described below by examples. However, the present invention is not limited to the following examples. <Sample> As an example 1, the spark plug100having the center electrode20satisfying the above expression (1) and the above expression (2) was produced. The value of L2/L1in the above expression (2) of the spark plug100of the example 1 was 0.250. As an example 2, the spark plug100having the center electrode20satisfying the above expression (1) and the above expression (2) was produced. The value of L2/L1in the above expression (2) of the spark plug100of the example 2 was 0.274. As a comparative example 1, a spark plug having a center electrode satisfying the above expression (1) but not satisfying the above expression (2) was produced. The value of L2/L1in the above expression (2) of the spark plug of the comparative example 1 was 0.351. In addition, as comparative examples 2 and 3, spark plugs each having a center electrode not satisfying the above expression (1) were produced. FIG.4is a sectional view schematically showing a configuration of a center electrode120of the comparative example 2.FIG.4illustrates a cross section likeFIG.2with a brim portion122and its vicinity being enlarged. The center electrode120provided in the spark plug of the comparative example 2 has, at a rear end side thereof with respect to the brim portion122, a diameter-reducing portion126whose diameter is reduced more than the brim portion122. Because of such a configuration (or a structure), the center electrode120of the comparative example 2 does not satisfy the above expression (1). Further, as compared with a size (a length) of a rear end side with respect to the boundary28between the connecting portion24and the leg portion21of the center electrode20of the examples 1 and 2 as shown inFIG.2, a size (a length) of a rear end side with respect to a boundary128between a connecting portion124and a leg portion121of the center electrode120of the comparative example 2 is large. The center electrode of the comparative example 3 has the same structure of an outward appearance as that of the center electrode120of the comparative example 2. <Impact resistance test> Impact resistance test was performed on the spark plugs100of the examples 1 and 2 and the spark plugs of the comparative examples 1 to 3. The impact resistance test was carried out using four samples for each of the examples and the comparative examples. The impact resistance test was performed in conformity with a method described in “JIS B 8031: 7.4 impact resistance test”, and impact of vibration amplitude of a stroke22(+1/0) mm was applied at a rate of 400 (+20/0) times per minute for 10 (+1/0) minutes. A degree of looseness of each of the center electrodes20and120of the samples after the test was evaluated. Further, impact resistance test was carried out by the same manner except that the test time was changed to 20 to 60 minutes, and a degree of looseness of each of the center electrodes20and120of the samples after the test was evaluated. Evaluation criteria is shown below.A: extremely good (no occurrence of the looseness)B: good (few occurrences of the looseness)C: not good (many occurrences of the looseness) A result of the impact resistance test and an evaluation result are shown in the following table. TABLE 1test time(the number of looseness/the number of samples)(D1-D2)/D110 min.20 min.30 min.40 min.50 min.60 min.L2/L1evaluationexample 1≤0.060/40/40/40/40/40/40.250Aexample 2≤0.060/40/40/41/41/41/40.274Bcomparative example 1≤0.064/4—————0.351Ccomparative example 2>0.060/40/40/40/40/40/40.261Acomparative example 3>0.060/40/40/40/40/40/40.190A From Table 1, the following can be seen. That is, in the cases of the spark plugs100of the examples 1 and 2 satisfying the above expression (1) and the above expression (2), the occurrences of the looseness of the center electrode20after the impact resistance test are few, then good results were obtained, as compared with the spark plug of the comparative example satisfying the above expression (1) but not satisfying the above expression (2). More specifically, in the case of the spark plug100of the example 1, no looseness of the center electrode20was observed in the impact resistance test for 60 minutes, and thus its evaluation result was A. Also, in the case of the spark plug100of the example 2, no looseness of the center electrode20was observed in the impact resistance test for 30 minutes, and only one looseness of the center electrode20was observed in the impact resistance test for 60 minutes, and thus its evaluation result was B. From comparison between the examples 1 and 2, it can be seen that as the value of L2/L1is smaller, the occurrence of the looseness of the center electrode20can be suppressed more. In contrast to this, in the case of the spark plug of the comparative example 1, the looseness of the center electrode occurred in all samples in the impact resistance test for 10 minutes, and thus its evaluation result was C. Regarding the spark plugs of the comparative examples 2 and 3 not satisfying the above expression (1), although their evaluation results were each A, as illustrated inFIG.4, since a size (a length) of the brim portion122is large as compared with the size (the length) L3of the brim portions22of the examples 1 and 2, the increase in the electric capacity cannot be suppressed. C. Other embodiment The present invention is not limited to the above embodiment, and can be realized with various configurations without departing from the scope of the present invention. For instance, technical features in the embodiment corresponding to technical features in each embodiment described in the summary of the invention can be replaced or combined as necessary in order to solve some or all of the problems described above or in order to achieve some or all of the effects described above. Further, if the technical features are not described as an essential in the present specification, it is possible to appropriately delete the technical features. The configuration or structure of the spark plug100of the above embodiment is merely an example, and can be variously modified, For instance, the connecting portion24has the tapered shape whose outside diameter is gradually reduced toward the top end side, but may be formed along a direction substantially perpendicular to the axis direction AD. Further, the step portion17is formed so that the diameter of the penetration hole11is smaller toward the top end side along the axis direction AD, but may be formed along a direction substantially perpendicular to the axis direction AD. Even with these configurations, the same effects as those of the above embodiment can be obtained. EXPLANATION OF REFERENCE 10insulator11penetration hole14large diameter portion15holding portion16small diameter portion17step portion20center electrode21leg portion22brim portion24connecting portion25core26electrode member28boundary29center of gravity30metal shell31tool engagement portion32male thread portion33seat portion34protruding portion35caulking portion36compressive deformation portion37top end surface38axial hole40ground electrode42electrode chip50metal terminal61top end side seal member (seal member)62resistor63rear end side seal member65gasket66,67ring members69talc90engine head93female thread portion95combustion chamber100spark plug120center electrode121leg portion122brim portion124connecting portion126diameter-reducing portion128boundaryAD axis directionCA axisG1gap | 31,599 |
11862944 | DETAILED DESCRIPTION The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which several embodiments of the invention are shown. This present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Like numbers refer to like elements throughout, and base100reference numerals are used to indicate similar elements in alternative embodiments. Referring initially toFIGS.1-7, a GIS device100according to the present invention is now described. The GIS device100includes a frame101defining a sealed interior compartment102, and an electrical breaker component103carried within the sealed interior compartment. The electrical breaker component103may be a circuit breaker, an earthing switch, contactor, reclosure, load break switch, isolator switch or disconnect switch, for example. For example, the frame101may comprise a metal material, such as steel. The GIS device100can be an AIS device or SIS device in other embodiments. As will be appreciated, the frame101includes a closable door (not shown). The sealed interior compartment102contains a dielectric gas (e.g. air in AIS embodiments or sulfur hexafluoride (SF6) and/or other gases but not limited to such as −N2, dry Air, CO2, Fluro nitrile, Fluro ketone or any gas mixture therein in GIS embodiments) or any liquid not limited to e.g. FR3 Natural esters), and comprises an air tight seal (in GIS embodiments) to contain the dielectric gas therein. In AIS embodiments, the sealed interior compartment102may only be enclosed (i.e. not necessarily sealed). The sealed interior compartment102illustratively includes an upper compartment104above the electrical breaker component103, and a lower compartment105below the electrical breaker component. The upper and lower compartment can be interchangeably designated based on the type of application. The GIS device100includes three incoming cable connectors106a-106ccarried in the upper compartment104, and three outgoing cable connectors107a-107ccarried in the lower compartment105. As will be appreciated, the three incoming cable connectors106a-106cand the three outgoing cable connectors107a-107crespectively carry three phases of power through the GIS device100. The GIS device100includes three incoming cable bushings110a-110crespectively coupled to the three incoming cable connectors106a-106cand carried outside the sealed interior compartment102adjacent the upper compartment104. The three incoming cable bushings110a-110crespectively receive three incoming power cables109(FIG.1). The GIS device100includes three outgoing cable bushings111a-111crespectively coupled to the three outgoing cable connectors107a-107cand carried outside the sealed interior compartment102adjacent the lower compartment105. The three outgoing cable bushings111a-111crespectively receive three outgoing power cables (not shown). As will be appreciated, the electrical breaker component103is configured to selectively control the flow of power between the three incoming cable connectors106a-106cand the three outgoing cable connectors107a-107cby selectively creating an open circuit therebetween. The electrical breaker component103includes additional circuitry configured to monitor the flow of power between the three incoming cable connectors106a-106cand the three outgoing cable connectors107a-107c,and selectively activate the electrical breaker component when the flow of power exceeds one or more operational thresholds (i.e. when electrical faults are detected). The GIS device100illustratively comprises a controller112coupled to the electrical breaker component103. As will be appreciated, the controller112comprises circuitry configured to execute control logic. For example, the controller112may comprise a general purpose integrated circuit device, or an application specific integrated circuit (ASIC) device. The GIS device100illustratively comprises a first optical sensor113acarried within the sealed interior compartment102and coupled to the controller112. In particular, the first optical sensor113ais carried within the upper compartment104above the electrical breaker component103. The GIS device100illustratively includes a second optical sensor113bcarried within the lower compartment105adjacent the three outgoing cable connectors107a-107cand coupled to the controller112. The GIS device100illustratively comprises third and fourth optical sensors113c-113dcarried outside the sealed interior compartment and coupled to the controller112. The third optical sensor113cis adjacent the three incoming cable bushings110a-110c,and the fourth optical sensor113dis adjacent the three outgoing cable bushings111a-111c. The GIS device100illustratively comprises a current transformer (CT)119configured to sense a current flowing via all phases. Thus, there are three CTs (one per phase), and these CTs will be providing a secondary current signal (proportional to the actual current flowing through the primary conductors). This signal is provided to the controller112. Of course, the number of optical sensors113a-113din the illustrated embodiment is merely exemplary. In some embodiments, additional optical sensors can be added to provide more coverage for detecting potential arc faults. In some embodiments where cost is a concern, the number of optical sensors113a-113dmay be reduced, and a plurality of mirrors135a-135ccould be deployed in combination and aligned with one or more of the plurality of optical sensors. In particular, the first and second optical sensors113a-113bin the sealed interior compartment102may be reduced to a single optical sensor and a plurality of mirrors135a-135cangled to reflect to the single optical sensor. Of course, there is some added detection delay due to the longer potential light propagation path, but the time delay would be negligible (order of nanoseconds). In addition, the frame101illustratively includes a plurality of viewing windows (136a-136c) carried by the sealed container, in such a way that it aligned with three phases and operator can see the moving grounding contacts (i.e. the aligned switch arms120a-120c) through the viewing windows. This feature provides the visual confirmation that the equipment is not grounded and thus, no internal arcing event has happened. The GIS device100illustratively comprises a grounding device114coupled downstream from the electrical breaker component103and being within the sealed interior compartment102. As perhaps best seen inFIGS.4-5, the grounding device114includes an axle115extending between the sealed interior compartment102and an exterior of the frame101. Of course, the transition of the axle115through the frame101does not disturb the sealed nature of the sealed interior compartment102(e.g. using a circumferential sealing mechanism, such as a set of O-rings). The grounding device114illustratively comprises a linkage116coupled to the axle115, and a grounding switch117coupled to the linkage and switching between a first open (i.e. ungrounded) state and a second closed (i.e. grounded)state. In particular, the grounding switch117comprises a plurality of aligned switch arms120a-120ccoupled to the linkage116and having a first end121, and a second end122opposite the first end. The first end121is permanently coupled (i.e. electrically grounded) to the frame101. The linkage116is configured to cause the second end122of the plurality of aligned switch arms120a-120cto couple to the three outgoing cable connectors107a-107cin the second closed state. In other words, the electrical path from the three outgoing cable connectors107a-107cis grounded to the frame101. The linkage116is configured to cause the second end122of the plurality of aligned switch arms120a-120cto be spaced apart from the three outgoing cable connectors107a-107cin the first open state. The linkage116illustratively includes a radial arm123coupled to the axle115in a rotationally fixed position, a vertical arm124coupled to the radial arm, and a transaxle125coupled to the vertical arm opposite the radial arm. The radial arm123, the vertical arm124, and the transaxle125may comprise one or more electrical insulating materials. As perhaps best seen inFIGS.6-7, each of the plurality of aligned switch arms120a-120ccomprises first and second elongate conductor arms126a-126bin alignment with each other, and first and second fasteners127a-127bcoupling the first and second elongate conductor arms together. Also, when switching between the first open state and the second closed state, the plurality of aligned switch arms120a-120cpivot about the second fasteners127a. The controller112is configured to cause the grounding switch117to switch to the second closed state based upon one or more of the first optical sensor113a,the second optical sensor113b,the third optical sensor113c,and the fourth optical sensor113d.In particular, each of the first optical sensor113a,the second optical sensor113b,the third optical sensor113c,and the fourth optical sensor113dmay comprise an image sensor circuit configured to detect arc conditions (i.e. arc flashes) adjacent thereto. In some advantageous embodiments, the image sensor circuit may comprise a high speed photodetector, such as ultrafast photodetectors or avalanche photodiodes (APDs) having a detection or rise time as low as 15 picoseconds. Additionally, the controller112is configured to cause the electrical breaker component103to switch to an open state based upon one or more of the first optical sensor113a,the second optical sensor113b,the third optical sensor113c,and the fourth optical sensor113d. The controller112is configured to control the grounding switch117via rotation of the axle115. In particular, the rotation of the axle115of about 40°-45° (but not limited to) should change the state of the grounding switch117between the first open state and the second closed state. The grounding device114illustratively includes an actuation device130coupled to a distal end131of the axle115, outside the sealed interior compartment102. In some embodiments, the controller112is configured to selectively activate the grounding device114and/or the electrical breaker component103depending on the location of the triggered optical sensors113a-113d.In some embodiments, the electrical breaker component103comprises a plurality of breaker components within the sealed interior compartment102, and the controller is configured to activate the respective breaker component closest to the triggered optical sensor. Referring now additionally toFIG.8A, in some embodiments, the actuation device130illustratively includes an elastic device/stored energy device132(e.g. torsion spring, spring, pneumatic, hydraulic) coupled to the distal end131of the axle115, and a release mechanism133coupled to the elastic device. Here, the controller is configured to activate the release mechanism133, which causes the elastic device132to rotate the distal end131of the axle115. Advantageously, the elastic device132can be charged manually or reset manually by personnel from the exterior of the sealed interior compartment102. In other embodiments, the actuation device130is carried within the sealed interior compartment102, and the distal end131of the axle115may not extend through the frame101. In yet other embodiments, even if the actuation device130is inside the sealed interior compartment102, the extension of the distal end131of the axle115may protrude out of the sealed interior compartment. This extension outside the sealed interior compartment102can be easily used to manually charge the elastic device. Another aspect is directed to a method of making a GIS device100. The method includes coupling an electrical breaker component103carried within a sealed interior compartment102of a frame101, and coupling a first optical sensor113acarried within the sealed interior compartment. The method further includes coupling a grounding device114to the electrical breaker component103and being within the sealed interior compartment102. The grounding device114includes an axle115extending between the sealed interior compartment102and an exterior of the frame101, a linkage116coupled to the axle, and a grounding switch117coupled to the linkage and switching between a first open state and a second closed state. The method comprises coupling a controller112to the electrical breaker component103, the first optical sensor113a,and the grounding device114and configured to cause the grounding switch117to switch to the second closed state based upon the first optical sensor. Referring now additionally toFIG.8B, another embodiment of the actuation device230is now described. In this embodiment of the actuation device230, those elements already discussed above with respect toFIG.8Aare incremented by100and most require no further discussion herein. This embodiment differs from the previous embodiment in that this actuation device230illustratively includes an electric (e.g. electromagnetic actuator, motorized actuator, or any mechanized actuator) actuator234coupled to rotate the distal end231of the axle115. In some embodiments, the distal end231of the axle115may have radial gearing, and the electric actuator234may comprise a linear actuator configured to engage the radial gearing, such as disclosed in the hereinbelow noted related patent applications. In other embodiments, the electric actuator234may comprise a rotary actuator configured to engage the distal end231of the axle115. Advantageously, the tripping delay time for this embodiment is less than the embodiment ofFIG.8A. Again, as with the embodiment ofFIG.8A, this mechanism can be reset and charged for the next grounding event from outside of the sealed compartment102. Referring now additionally toFIG.9, a diagram1000shows timing in the GIS device100during an arc fault event. Starting from the far left bar, the arc fault event occurs. The next bar represents the delay from occurrence of the arc fault event to when any of the optical sensors113a-113dgenerates a tripping signal (i.e. using high speed photodetectors, about 2-3 milliseconds). The time between the second and third bars is noted as “a” and represents the time difference between the tripping signal being sent and the electric actuator234being energized. The time between the second and fourth bars is noted as “b” and represents the time difference between the tripping signal being sent and the electric actuator234starting movement of the grounding device114. The time between the fourth and fifth bars is noted as “c” and represents the operational delay of the grounding device114(i.e. 4-8 milliseconds). When the grounding device114is activated, the electrical breaker component103is also activated. The electrical breaker component103is slower than the grounding device114, and the total interrupting time may take up to 2 seconds. Advantageously, the GIS device100may provide improvements over existing arc fault mitigation devices. Firstly, the GIS device100may recognize and mitigate the arc fault in less time than existing approaches. Indeed, in embodiments using high speed photodetectors, the only delay in clearing the arc fault is the delay time of the electric actuator. Moreover, the GIS device100may deploy its arc flash mitigation approach without disturbing the sealed interior compartment102and releasing the dielectric gas, which may be toxic (due to biproducts of the internal arc burning). In fact, is some applications, once the cause of the arc fault has been cleared, the GIS device100may be readily returned to a normal operational state without opening the sealed compartment101. Moreover, the GIS device100may deploy its arc flash mitigation approach multiple times without the need for replacement. Also, the GIS device100includes an arc flash mitigation approach that is less expensive than existing approaches. Yet another aspect is directed to a method of operating a switchgear device100. The method includes providing an electrical breaker component103carried within an interior compartment102of a frame101, providing optical sensors113a-113dcarried within the interior compartment, and providing a grounding device114coupled to the electrical breaker component and being within the interior compartment. The grounding device114includes an axle115extending between the interior compartment102and an exterior of the frame101, a linkage116coupled to the axle, and a grounding switch117coupled to the linkage and switching between a first open state (i.e. ungrounded state) and a second closed state (i.e. grounded state). The method comprises operating a controller112coupled to the electrical breaker component103, the optical sensors113a-113d,and the grounding device114and configured to cause the grounding switch117to switch to the second closed state based upon at least the first optical sensor. The method also includes actuating the grounding device114from outside the interior compartment102. Helpfully, the user can reset or charge the grounding device114without opening the interior compartment102. The method also includes actuating the grounding device114a plurality of times without replacing or servicing the grounding device114(i.e. servicing beyond manually resetting or charging it). Other features relating to switchgear device are disclosed in co-pending applications: SWITCHGEAR SYSTEM HAVING TRANSLATABLE AND ROTATABLE TRUCK AND ASSOCIATED METHOD, U.S. Patent Application Publication No. US2022/0271516; SWITCHGEAR SYSTEM HAVING CHAIN DRIVEN CIRCUIT BREAKER AND ASSOCIATED METHODS, U.S. Pat. No. 11,735,893; SWITCHGEAR SYSTEM HAVING TRUCK DRIVEN SHUTTER MECHANISM, U.S. Pat. No. 11,742,639; RAPID X-RAY RADIATION IMAGING SYSTEM AND MOBILE IMAGING SYSTEM, U.S. Patent Application Publication No. US2022/0326165; MEDIUM-VOLTAGE SWITCHGEAR SYSTEM HAVING SINGLE PHASE BREAKER CONTROL, U.S. Pat. No. 11,735,385; SWITCHGEAR SYSTEM HAVING CONTACT ARM ASSEMBLY FOR SWITCHGEAR CIRCUIT BREAKER, U.S. Pat. No. 11,742,638; SWITCHGEAR SYSTEM THAT DETERMINES CONTACT EROSION IN CIRCUIT BREAKER, U.S. Patent Application Publication No. US2023/0197362; TESTING SYSTEM THAT DETERMINES CONTACT EROSION IN CIRCUIT BREAKER, U.S. Patent Application Publication No. US2023/0194609; SWITCHGEAR GROUND AND TEST DEVICE HAVING INTERCHANGEABLE GROUNDING BARS, Application Ser. No. 17/651,069; and CIRCUIT BREAKER HAVING VACUUM INTERRUPTERS AND SINGLE-PHASE CONTROL WITH MAGNETIC ACTUATORS AND ASSOCIATED METHODS, Application Ser. No. 17/652,112, all incorporated herein by reference in their entirety. Many modifications and other embodiments of the present disclosure will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the present disclosure is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims. | 19,302 |
11862945 | DETAILED DESCRIPTION FIG.1illustrates an electrical system5for a building (e.g., a home electrical system) according to an exemplary embodiment. Electrical system5includes an electric meter housing18that encloses a contact block that is electrically coupled to an off-site utility power source (not shown) and configured to provide power from the off-site utility source through an electricity meter20to a distribution or panel11. Distribution panel11(e.g., a circuit breaker box, a fuse box, etc.) is configured to route electrical power to electrical loads (not specifically shown inFIG.1) in the building. Electrical system5also includes a generator13(e.g. a home standby generator) for providing electrical power to distribution panel11instead of (or potentially in addition to) the utility power provided through the meter housing18. For example generator13may be configured to provide power to distribution panel11through a transfer switch in the event of a utility power failure. According to various exemplary embodiments, generator13may be a standby generator, a portable generator, or any generator capable of providing power to a distribution panel of a building. Generator13may be an engine driven electrical generator that uses natural gas, propane, diesel or gasoline as a fuel. Alternatively, standby generator may be a battery backup system, fuel cell power source, solar power system, wind or other alternative energy source, or any other on-site power source. The electrical system5includes a meter socket adapter10that is positioned between the meter housing18and the distribution panel11. The meter socket adapter10includes an internal transfer switch controller and contacts to control the supply of power to the electric loads from either the utility or generator. The meter socket adapter10is hard wired to the on-site power source, such as a standby generator13, through a pre-wired cable12. The factory installed cable12can be a 25-foot, 50-foot or any other desired length cable that connects to the standby generator13or disconnect box in a known manner. The cable12enters into the outer housing14to provide power to a set of internal contacts that allows the transfer switch components of the meter socket adapter10to switch to power from the standby generator when the utility-side power is interrupted. The outer housing14is preferably made of metal, such as steel or aluminum. However, other materials, such as a durable composite, are contemplated as being a viable alternative. As can be seen inFIG.2, the meter socket adapter10is plugged into a meter socket formed as part of the conventional meter housing18. The meter housing18is conventionally mounted on the exterior of a home or on the interior of a building. The meter housing18typically receive an existing electricity meter20through the interaction between contact blades on the back surface of the electricity meter20and receiving jaws formed within the meter socket. The meter socket adapter10of the present disclosure is positioned between the meter socket housing18and the electricity meter20. In the embodiment illustrated, the meter socket adapter10is formed as a component that can be received in an existing meter socket16, such as when the meter socket adapter10is being used with an existing home. However, if the meter socket adapter is being installed at a new home construction, the meter socket adapter10and the meter socket16could be combined into a single unit. Such embodiment would be useful during new home construction and would eliminate the need for a separate meter socket. As illustrated inFIGS.3cand4, the meter socket adapter10includes four spaced contact jaws22that each receives a contact blade formed on the back of the electricity meter in a conventional orientation. The contact jaws22are electrically connected to contact blade24that extend from the back surface26of the meter socket adapter10, as shown inFIG.3b. The contact blades24are received within corresponding contact jaws formed in the meter socket. In this manner, the meter socket adapter10can plug right into the meter socket16of the meter housing18while the electricity meter20can then plug directly into the contact jaws22formed as part of the meter socket adapter. The electrical contact blades24provided on the meter socket adapter10plugs into the contact jaws and provide an electrical path between the utility supply-side bus bar and the home load-side bus bar of the meter socket. Typically, four contact blades are used, two for each side. The outer housing14of the meter socket adapter10encloses automatic transfer switch contacts and a transfer switch controller that first senses when utility power has been lost and secondarily switches the power supply from the utility source to the on-site power source (standby generator). The meter socket adapter10provides a much simpler, faster and cost-effective generator installation. In the embodiment illustrated, the meter socket adapter has 200 amp utility service switching capability and up to 200 amp on-site power source switching capability. In alternative embodiments, the meter socket adapter can have larger or smaller switching capabilities (e.g., 100 amp, 400 amp, etc.). In the exemplary embodiment, the transfer switch includes a load sensor (current transformer) on the load-side of the adapter plug. Alternatively, the current transformer could be mounted on the generator side. This sensor detects the power being used by the loads by measuring the current flow to the loads. Preferably, one load sensor is on each power conductor feeding the distribution panel. In addition to the transfer switch controller, the meter socket adapter10also includes load management controls contained inside the outer housing14. The load management controls communicate to load relays that are located in series with electric loads at the home or business. To prevent a generator overload, wired or wireless communications can be used to activate the load relays to provide load shedding capabilities. Although the load management controls and load sensing components are shown within the meter socket adapter10, these two elements could be installed inside the home in a separate enclosure mounted near the distribution panel and could also contain the load shedding relays. Alternatively, load management may not be used at all if the standby power source is large enough or if it is not required by code. Furthermore, it is contemplated that the load management controller could be located at the generator and thus removed from within the meter socket adapter10. The load management controller contained within the outer housing14functions to selectively shed loads from the power distribution system and subsequently reconnect the loads to the power distribution system. The load management controller may reconnect the loads to the power distribution system depending upon the amount of power drawn by the loads and the power available from the standby power source. The details of the load management control board can vary depending upon the particular power distribution system. The details of one exemplary load management controller and its method of operation are set forth in U.S. Pat. No. 8,415,830, the disclosure of which is incorporated herein by reference. However, other types of load management systems and methods of operation are contemplated as being within the scope of the present disclosure. The load management controller is contained within the housing such that both the transfer switch and the load management components required to selectively shed/reconnect loads within the home serviced by the generator can be installed as a single device contained within the housing. The meter socket adapter10includes over-current protection devices that are hard wired between the utility power supply and the transfer switch. Preferably, these over-current protection devices are devices with high current interrupting capacity (AIC) typically in the range of 22,000-25,000 amps or more. One example of a high current interrupting device is a fuse. The transfer switch includes a two-pole form-C transfer switch that provides “break-before-make” operation when switching between power sources of utility and on-site standby power. The transfer switch can be of any type, such as one that uses solenoid actuation to automatically open and close the contacts. Alternatively, two separate 2-pole A-form (or B-form) switches could be utilized to select the power source (utility or generator) to be provided to the load. Doing so requires inter-lock circuitry to provide “break-before-make” operation and to prevent both switches from being closed at any one time. An alternative inter-lock can also be done via software. FIGS.5-7illustrate the meter socket adapter10securely mounted to the utility meter housing18. Typically, the utility meter housing18will be mounted to a wall of a building or home. The utility meter housing18can be mounted to either an exterior wall of a building or, in some instances, can be mounted inside a building. As discussed previously, the utility meter housing18typically receives the electricity meter20. However, when the meter socket adapter10is utilized, the electricity meter20is received within the meter socket adapter10while the meter socket adapter10is received within the meter socket of the meter housing18. In the embodiment shown inFIGS.5-7, a support bracket28is attached to a back surface30of the outer housing14. Although not required, the support bracket28is typically attached to the same wall that supports the meter housing18. The support bracket28provides support for the bottom end32of the meter socket adapter10. As can be best understood inFIG.7, the support bracket28includes a pair of extending horizontal mounting portions34that can be securely attached to a wall surface. A pair of adjustment bolts allow the depth of the support bracket28to be adjusted depending upon the thickness of the meter housing18. Referring back toFIG.5, in the embodiment illustrated, the meter socket adapter10includes a first power compartment38and a second control board compartment40. In one contemplated embodiment, these two compartments can be accessed separately. In the embodiment illustrated, the contacts and connections for the electricity meter and transfer switch are contained within the upper power compartment38while the control boards and electrical wiring for the transfer switch controls and contacts, as well as the load management controls, are included within the control board compartment40. As illustrated inFIG.7, the upper power compartment38includes a protective cover42having a central opening44that allows the meter20to extend through the cover42, yet retains the meter flange with its “ringless” cover design, as is known in the industry. Alternatively, a ring-type meter retention system (not shown) can be used with the appropriate protective cover and retaining ring. The cover42is received beneath the top cover46and is held in place by a pair of connectors48, or more conventional pivoting latch (not shown). When the connectors48are removed, the entire cover42can be removed, as illustrated inFIGS.8and9. In the embodiment illustrated, the meter socket adapter contact block is designed with a horn bypass feature. This feature includes a bypass tab56on the bus bar for both the load-side and line-side of the contact block. The horn bypass is a conventional feature that allows a jumper cable to bypass the meter such that the meter can be removed/exchanged without disrupting power to the home. In the embodiment illustrate, when the cover42is removed, a clear plastic shield50is exposed. The plastic shield50covers a pair of upper bypass openings52and a pair of lower bypass openings54. The plastic shield50thus allows the meter to be removed, as shown inFIG.9, while still covering the bypass tabs56and58. The live bypass tabs56of the line-side are contained within the upper bypass openings52while the load-side contacts58are contained within the lower bypass openings54. The plastic shield50includes a central opening such that the shield50can be removed without removing the meter. The plastic shield50is designed to protect a service technician from inadvertent contact whenever the line bypass tabs are energized. Although the shield50is described as being formed from a clear plastic material, it is contemplated that other types of materials (such a metal) could be utilized while operating within the scope of the present disclosure. When the plastic shield50is removed, as shown inFIGS.8and10, the line-side and load-side bypass tabs56and58are exposed. The bypass tabs56,58allow jumpers to be connected between the load-side bus bar and the line-side bus bar to bypass the meter20. This is important for servicing the meter without having to interrupt power supply to the home or business served by the meter. As an example, if the meter20needs to be serviced, service personnel remove both the outer cover42and the plastic shield50to expose the bypass tabs54and56. Once these bypass tabs are exposed, a jumper is installed to bypass the meter20. Once the meter has been bypassed, the meter can be pulled from the meter socket adapter10for servicing. When the meter is removed without bypassing, the lower load-side portion of the meter socket adapter is completely de-energized, while the upper line-side contacts may still be energized. FIG.12illustrates a pair of cylindrical guards60that surround each of the live bypass tabs56and the upper line-side contact jaws22. The cylindrical guards60restrict inadvertent contact between the service personnel and the live bypass tabs56. While guards60are shown to be cylindrical inFIG.12, guards60may be any appropriate shape so as to restrict inadvertent contact with live bypass tabs56. In the embodiment illustrated, each of the cylindrical guards60are formed from a clear plastic, although other non-conductive materials are contemplated as being within the scope of the present disclosure. As illustrated inFIG.12, the meter socket adapter10includes the four contact jaws22. As previously described, the contact jaws22receive mating blades formed on the back of the electricity meter. The spacing between the contact jaws22is defined and dictated by the spacing of the contact blades on the back of the electricity meter20. Referring now toFIG.11, the meter socket adapter10is shown with the meter and the clear shield50removed. The bypass tabs56and58are shown as being accessible through the upper bypass openings52and the lower bypass openings54. Likewise, the contact jaws22can be seen in this view. 10062FIG.11aillustrates the internal components contained within the meter socket adapter10once the front cover62is removed. As illustrated, the central opening in the front cover62is smaller than the flange portion of the electrical meter. Thus, the meter must be removed before the front cover62can be removed. Removing the meter acts as a disconnect to the lower portion of the meter socket adapter and de-energizes that portion. As can be understood inFIG.2, the front cover62is a single component that, once removed, provides access to both the power compartment40and the control board compartment38. In an alternate embodiment of the disclosure, the power compartment38and the control board compartment40are separately accessible. Referring toFIG.12, the meter socket adapter10includes a key switch64that is connected through a series of wires66to the controller of the transfer switch. The key switch64is a multi-position switch that allows an operator to select between different modes of power operation. These different modes could include “normal operation”, “generator service”, “system test”, “on-site power source selector” and “generator disable” modes. The multi-position switch64is shown as extending through the outer housing of the meter socket adapter10and controlled by the position of a key68. However, different types of switches and activation devices are contemplated as being within the scope of the present disclosure. Further, it is contemplated that the key switch64could be eliminated in other embodiments. In one embodiment of the disclosure, the key switch is movable between three different positions. The first position, referred to as the service mode, kills the AC power to the generator only. When the key switch is in this position, power is disabled to the generator, which allows service to be performed on the generator. In the second position, the key switch is in the normal mode, which allows the transfer switch controller and load management controller to operate in their normal mode. The third position for the key switch is the system test position. When the key switch is moved to this position, the transfer switch controller simulates a loss of utility power. Upon this simulated loss of power, the transfer switch controller signals the activation of the standby generator and transfers generator power to the building. In this manner, the key switch is able to test the operation of the standby generator system quickly and easily. In prior systems that do not include a key switch, an operator is required to either pull a fuse from the transfer switch or de-activate a breaker to simulate the loss of utility power. Additional positions for the key may be added if required. Referring back toFIG.3b, the meter socket adapter10of the present disclosure includes a series of locking lugs70that are operable to engage an inner surface72of the meter housing18.FIG.13illustrates the locking lugs70in additional detail. Each of the locking lugs70includes a mounting portion74and a locking leg76. The mounting portion74includes a bolt78. InFIG.13, each of the locking lugs70is in its retracted position such that the mounting lug80can be inserted into the circular opening defined by the meter housing and which provides access to the meter socket. The opening in the meter housing is sized similar to the opening82formed on the back of the meter socket adapter1. As illustrated inFIG.14, once the mounting lug80is inserted, each of the locking lugs70is moved to the locking position shown inFIG.14. In this position, each of the locking legs76extends radially outward past the inner edge84that defines the opening82. When in this position, the four locking lugs70engage the inner wall of the meter housing to support the weight of the meter socket adapter10on the meter housing. Referring back toFIG.12, each of the bolts78includes a head86. When the head86is rotated, the rotation causes the locking lugs to move between their retracted and extended positions. Thus, once the meter socket adapter10is positioned such that the mounting lug is received within the meter socket, each of the bolt heads86is rotated to cause the locking lugs to move to their extended position to hold the meter socket adapter10on the meter housing. Although locking lugs are shown in the embodiment illustrated, it is contemplated that other types of mounting arrangements could be utilized to secure the meter socket adapter10to the meter housing. In addition, different types of meter housings are contemplated that will require various other types of mounting arrangements to secure the meter socket adapter10. In each case, the contact blade extending from the back surface of the meter socket adapter10must be received within the contact jaws formed in the meter socket. Referring back toFIG.13, the contact blades24can clearly be seen in the desired spaced relationship such that the contact blades24can be received within the contact jaws formed in the meter socket. In the embodiments previously described, the meter socket included a series of contact jaws that received the standard contact blades, such as shown inFIG.13. However, different meter manufacturers have different types of meter sockets that are designed to receive and retain their meters. One example of an alternate meter socket is shown inFIG.15. In this embodiment, a bypass lever88is used to lock the meter in place once the meter is received within the contact jaws90. The bypass lever88moves elements of the contact jaws90toward each other to lock the meter in place. When the meter is to be removed, the bypass lever88is moved to its extended position shown inFIG.15. When the bypass lever88is moved to the extended position, bypass blades of the contact block are moved into line and load positions, which allows current to flow through the meter socket with the meter either in or out of the socket. Since the bypass lever88extends out well past the meter housing, the meter socket adapter10described previously cannot be used with the meter socket illustrated inFIG.15. As a result, a contact adapter92has been developed, and is illustrated inFIGS.16-19. The contact adapter92includes a series of contact jaws94extending from a front surface96. The front surface96also includes a neutral jaw95. The neutral jaw95provides a neutral connection from the generator to the home or building by allowing the neutral from the bus bar to be connected to the jaw95. The back surface98includes a series of contact blades100and a neutral blade101. The neutral blade101is provided to fit into the neutral contact jaw if available. If the neutral contact jaw is not available, the neutral can be shorted to the bus bar. By connecting the neutral wire from the bus bar to neutral blade101of contact adapter92, the installation of meter socket adapter10is simplified. With this configuration, the installer does not need to “fish” a neutral wire out of the housing of the utility meter socket18and into the housing of meter socket adapter10, all while simultaneously attempting to attach meter socket adapter10to utility meter socket18. Instead, a short neutral wire can be run from the bus bar of utility meter socket18to neutral blade101of contact adapter92prior to coupling of meter socket adapter10, thereby greatly simplifying the installation process. When the meter socket adapter10of the present disclosure is used with a meter contact block as shown inFIG.15, the contact adapter92is utilized. Initially, the contact adapter92is installed into the position as shown inFIG.17. When in this position, the bypass lever88shown inFIG.15can be moved to its locking position to securely lock the contact adapter92in the position shown inFIG.17. Once in this position, the contact jaws94are accessible through the opening102formed in the outer surface104, as illustrated inFIG.16. The contact adapter92thus allows the meter socket adapter10described previously to be used with the contact arrangement shown inFIG.15. In an alternative embodiment, the meter socket adapter may be provided with an additional bypass lever similar to bypass lever88to provide meter bypass and locking functionality. FIGS.2and20illustrate a contact guard106that can be used with the contact adapter92. The contact guard106is a protective cover that is positioned on the contact adapter and functions to cover the contact jaws94and the neutral jaw95. The contact guard106is preferably formed from a non-conductive material, such as plastic and includes a series of guard blocks108aligned with each of the contact jaws94. The contact guard106restricts inadvertent contact between the service personnel and the live contact jaws94. The use of the contact guard106is optional. The steps required to install the meter socket adapter10including the transfer switch will now be described. Initially, when the meter socket adapter10is to be installed at a home or business, the first step in the installation process is to remove the electricity meter from the existing utility meter socket, illustrated by reference numeral18inFIG.2. This is accomplished by the utility removing power at the upstream transformer. After power is removed, the utility meter can be removed and the installation commenced. With the utility meter removed, in an embodiment that utilizes the contact adapter92, the adapter92can then be installed. In such an embodiment, only the front cover42needs to be removed from the meter socket adapter10. After the contact adapter92is installed, the existing meter cover is re-mounted and the contact adapter92extends through the cover as shown inFIG.16. In an embodiment that does not utilize the contact adapter92, once the utility meter20has been removed, the front cover62of the meter socket adapter10is removed such that the internal components of the meter socket adapter10are accessible, as shown inFIG.11. In such an installation, the neutral wire must pass through the hole in the front cover and be connected to the neutral terminal block in the lower left corner of the meter socket adapter10. In an embodiment that utilizes the contact adapter92, the neutral contact is created by the neutral jaws95and either a blade that extends through making contact with a set of neutral jaws existing in the meter box or a short wire connecting the neutral jaw of the contact adapter to the neutral bus of the meter box. Once in this condition, the meter cover is installed and the meter socket adapter10is inserted into the meter socket such that the contact blades24extending from the mounting lug are received within the corresponding contact jaws formed in the meter socket. Once in this condition, the bolt heads86are rotated, causing the locking lugs70to rotate into the locked position shown inFIG.14. Once the locking lugs are in this position, the meter socket adapter10is supported as illustrated inFIG.11a. The support bracket28can be adjusted to further aid in supporting the weight of the meter socket adapter10. Once mounted, the front cover62is mounted to the outer enclosure, as shown inFIG.11. After the front cover is positioned, the plastic shield50shown inFIG.9is installed. In the preferred embodiment that utilizes the contact adapter92, the front cover62and the plastic shield50do not need to be removed during installation. The meter is inserted into the contact jaws as illustrated inFIG.8. Once the meter is installed, the cover42is attached, as shown inFIG.7. As can be understood by the above disclosure, if the meter socket adapter10including the enclosed transfer switch and load controller is no longer desired, the meter socket adapter10can be easily removed by simply removing the meter20and disconnecting the meter socket adapter. Once the meter socket adapter has been removed and the contact adapter92is removed, the electricity meter20is again installed in its original meter socket formed within the housing18. As can be understood in the foregoing disclosure, the main utility service disconnect is not affected when using the meter socket adapter10of the present disclosure, since the meter socket adapter10is an extension of the meter socket. The main disconnect remains in the distribution panel. Further, there is no need to move the neutral-to-ground bonding point that is typically located in the distribution panel, which greatly reduces the amount of time needed to install the transfer switch. FIGS.21-28illustrate a second, alternate embodiment of the meter socket adapter120constructed in accordance with the present disclosure. Many components of the second embodiment of the meter socket adapter120are common with the first embodiment shown inFIGS.2-20. For the common components, common reference numerals will be utilized. In addition, it should be understood that the internal switching components to switch between the utility power source and the auxiliary power source, such as a standby generator, remain consistent between the first embodiment and the second embodiment. Likewise, the load management controller contained within the second embodiment of the meter socket adapter120functions in the same manner previously described in the present disclosure. The second embodiment shown inFIG.21includes a reconfigured outer housing122that defines a separate upper meter compartment124and a lower control compartment126. The meter compartment124and the control compartment126are separated within the housing122by a divider wall128that is securely attached between the pair of spaced sidewalls130. The divider wall128completely separates the meter compartment124from the control compartment126to isolate the connections needed for the electricity meter20from those needed to transfer power from the utility power source to the alternate power source. As illustrated inFIG.21, the housing122mounts to the meter housing18utilizing the contact adapter92which includes the contact guard106installed thereon. As discussed previously, the utility meter housing18includes a removable outer cover104. As illustrated inFIG.21, the meter compartment124receives an upper cover132while the control compartment126receives a lower cover134. The upper cover132and the lower cover134are separate components that can be independently removed and/or attached to the outer housing122. The lower cover134conceals a lower guard136that is separately attached to the outer housing122to conceal the transfer switch component and load management components contained within the control compartment126. In the embodiment shown inFIG.21, the electronic operating components contained within the control compartment126are connected to the secondary power source, such as a generator, through a cable12that is received in a junction box138. The cable12extends from the meter socket adapter120to the junction box138and has a length of six feet. However, the length of the cable12could be twenty-five feet or more depending upon the desired location of the junction box138relative to the meter socket adapter120. The junction box138includes a connector block140that can provide the required electrical connections between a cable142coming from the generator or other type of auxiliary power source. The electrical connections made within the junction box138allow for a remote service disconnect that is located externally from the electrical components and connections made within the meter socket adapter120. The connector block140shown inFIG.21can include fuses and a switch to interrupt the electrical connections between the generator and the meter socket adapter120. As illustrated inFIG.22, the, junction box138includes an outer cover144that conceals the electrical connections made by the connector block140. The outer cover144can be removed to access the electrical connections within the junction box138in a conventional manner. Referring now toFIGS.22and23, these figures illustrate the meter socket adapter120as installed on the meter socket housing18. The installation of the meter socket adapter120onto the meter socket housing18is similar to the installation process described with respect to the first embodiment of the meter socket adapter10shown in drawingFIGS.2-20. As in the first embodiment, the meter socket adapter120includes external contact blades that extend from the back surface of the meter socket adapter120and are received within corresponding contact jaws formed in the contact adapter received within the contact jaws formed in the meter socket. Once the meter socket adapter120is installed as shown inFIG.23, the support bracket28can be used to support the lower portion of the outer housing122along the outer wall that supports the meter socket18. As illustrated inFIGS.22and23, when the electricity meter20is installed within the meter socket adapter120, the upper cover132is securely attached to the outer housing122. A top cap146covers the upper portion of the upper cover132. The lower portion of the upper cover132includes a locking tab148that is positioned adjacent to a corresponding locking tab150that extends from the divider wall128, as shown inFIG.21. When the upper cover132is installed as shown inFIG.22, a utility can use a security tag (not shown) to join the pair of locking tabs148and150. The security tag allows the utility to prevent unauthorized access into the meter compartment124. If the utility needs to service the electricity meter, the utility removes the security tag and can then remove the upper cover132. If another party attempts to tamper with the electricity meter20, the security tag must be removed, which will indicate to the utility that unauthorized access has been granted into the meter compartment124. If the utility needs to access the metering, components contained within the meter compartment defined by the meter socket adapter120, the utility first removes the meter20from the meter socket adapter120, as is shown inFIG.24. Once the meter has been removed, the contact guard106can be accessed by the utility. If the utility needs to access the components contained within the meter compartment, the utility can remove the security tag that extends between the pair of locking tabs148,150and can then remove the upper cover132. Once the upper cover has been removed, as illustrated inFIG.25, the meter compartment124can be accessed. Once inside the meter compartment124, the load side bypass tabs56and bypass tabs58can be used to bypass power past the meter socket to provide power to the home with the meter removed, as was described previously in the first embodiment. As can be understood inFIG.25, when utility service personnel is accessing the meter compartment124, the lower control compartment is completely sealed and electrically isolated by both the lower cover134and the divider wall128. In this manner, the utility can simply remove the upper cover132and access all of the electrical connections and components that are required for servicing a meter. In this manner, the meter compartment124effectively functions the same as the meter housing and meter socket. FIG.26further illustrates the internal components contained within the meter compartment124, which include the bypass tabs56and58as well as the contacts used to supply power from the utility to a home through the meter. The operating components contained within the meter compartment124are similar to those described previously with respect to the first embodiment. As described previously, the meter socket adapter120of the present disclosure includes a control compartment126that is separate from the meter compartment124. The complete separation between the meter components contained within the meter compartment124and the control components contained within the control compartment126allows for separate access and servicing of these two portions of the meter socket adapter120. As discussed above, if utility service is required, the upper cover132can be removed to provide access to the meter components. Likewise, if service is required for the switching components and load shedding components, access can be provided to only these components without providing access to the meter socket. If a generator service is needed for the components associated with the standby generator, the service personnel can access the control compartment126without being given access to the meter compartment124. As illustrated inFIG.23, if access is required to the control compartment, the access is initially provided by removing the lower cover134. The lower cover134is attached utilizing a series of screws152that attach the lower cover134to the outer housing122. Once the screws152have been removed, the lower cover134can be removed, as illustrated inFIG.27. Once the lower cover has been removed, the service person is able to view and access the lower guard136. The lower guard136is separately attached to the outer housing122by an additional series of connectors154. Prior to removing the lower guard136, the user has access to a power interrupt switch156. The power interrupt switch156is a circuit breaker in the embodiment illustrated. The power interrupt switch156, when moved to an open position, interrupts all power to the components contained within the control compartment positioned behind the lower guard136. In this manner, service personnel can open the power interrupt switch156to completely kill power within the control compartment before servicing the transfer switch controller and components as well as the load management controller. It is contemplated that when service is required for the generator or the control components, the service personnel will first disconnect the generator prior to opening the power interrupt switch156. If the generator is not disconnected first, opening the power interrupt switch156will be sensed by the generator as a loss of power, which will initiate the automated starting of the standby generator. The power interrupt switch156can be accessed only after the lower cover136has been removed, which requires a tool (screwdriver) to remove the screws152. Once the power interrupt switch156has been opened, the connectors154can be removed and the lower guard136removed to provide access to the control components within the control compartment126, as best shown inFIG.28. As can be understood inFIG.28, when the service personnel has access to the control compartment126, the electricity meter20remains installed and the generator service personnel cannot access any of the components contained behind the upper cover132. In addition to the power interrupt switch156, trained service personnel can also access a pair of touch-safe fuse holders158. As can be understood inFIG.28, when the lower guard is removed, the service personnel can access the transfer switch components and load control components that are each housed within the control compartment126. Since the meter socket adapter120is connected to the generator through the junction box138, the junction box138allows for a generator field connection and an optional isolation location that is located separately from the meter socket adapter120. Referring now toFIG.26, in the second embodiment, the contact adapter92includes a pair of neutral jaws160instead of the single neutral jaw95shown inFIG.18. The additional neutral jaw provides a separate connection between the outer housing122to electrically ground the outer housing122and the generator housing. Thus, a neutral bonded connection does not need to be created within the meter socket adapter120, which allows the meter socket adapter120to be positioned at a home without requiring complex and expensive electrical connections. Referring toFIG.29, a block diagram of a power management system165is shown, according to an exemplary embodiment. The power management system165includes a meter mounted transfer switch162provided between the meter20and the meter housing18, coupled to the meter socket adapter10. The power management system165also includes a power management module164, generator168, wireless gateway172, and appliance166. The power management system165selectively provides power to one or more electrical loads. The power management system165may connect and disconnect the electrical loads from power using relays based on available power from a primary power supply (e.g., utility power) and/or a secondary power supply (e.g., generator168). As shown inFIG.29, the use of load controls in the meter mounted transfer switch162is replaced by the application of a controller (e.g., generator controller174and/or load management controller170) in or connected to the generator168, which communicates wirelessly with the power management module(s)164. In this way, time and costs may be saved on wiring the power management system165. In some embodiments, the meter mounted transfer switch162does not include any controllers within the enclosure. Accordingly, with less complex transfer circuitry176and fewer components, the cost of the meter mounted transfer switch162can be greatly reduced. Additionally, the meter mounted transfer switch162can be more compact because less room is needed to accommodate internal components. For example, the meter mounted transfer switch162may include one or more contact blades184extending from the housing to be received within a socket (e.g., a meter socket, a socket of meter socket adapter10, etc.), one or more contact jaws182structured to receive an electrical connection from an electricity meter, and simplified transfer circuitry176. The transfer circuitry176includes at least one transfer switch that changes between first and second positions based on control signals received from the generator controller174. In some embodiments, the meter mounted transfer switch162includes two large fuses (e.g., 250-amp fuses) in the transfer circuitry176instead of a circuit breaker. The two fuses may provide overcurrent protection to circuitry of the meter mounted transfer switch162. The transfer circuitry176in the meter mounted transfer switch162may include 200-amp latching relays to replace the function of a double pole, double throw (DPDT) contactor. In other embodiments, the meter mounted transfer switch162may include other latching relays. The latching relays may not switch unless no power is detected on the load side of any latching relays of the meter mounted transfer switch162. In other contemplated embodiments, the meter mounted transfer switch162may be integrated within the meter socket adapter10as a single component of the power management system165. In contemplated embodiments, the generator168is the same as or similar to the generator13described above. The generator168includes a generator controller174positioned within a housing of the generator168. The generator controller174may be configured to connect the generator168to at least one of the electrical loads after detecting a loss of power from the utility power supply. The generator controller174is also structured to control the power management module164, for example, via the load management controller170and/or via the generator controller174. The generator168may communicate (e.g., via the generator controller174) to the wireless gateway172to instruct the load management controller170to control power management module164. In some embodiments, the generator controller174is located within a control compartment of the generator168. The generator168may include a removable cover for the control compartment to provide access to the generator controller174. The power management system165also includes power management module164. The power management module164is hard-wired between the distribution panel11and the appliance(s)166via the building's power lines. The power management module164is electrically connected to distribution panel11through wired power lines. The power management module164can be provided between a wall socket and a lead of an appliance166that normally operates on a utility power supply of a home. The power management module164may include one or more contact blades extending from the housing to be received within a socket (e.g., a wall socket electrically connected to the utility power of a home and distribution panel11), one or more contact jaws structured to receive an electrical load (e.g., appliance166), and simplified switching circuitry. The switching circuitry includes at least one transfer switch that changes between first and second positions based on controls received (e.g., via wireless gateway172) from the load management controller170of the wireless gateway172. In some embodiments, the power management system165includes one or more power management modules164. The load management controller170may monitor the load experienced by the secondary power source (e.g., generator168). The load management controller170can be configured to control the power management module164. The load management controller170selectively disconnects one or more electrical loads (e.g., appliances166) based on the amount of power still available from the generator168and the power required by the one or more electrical loads. The information on the amount of loads experienced is accumulated at the secondary power source (e.g., generator168) itself instead of at the switching assembly (e.g., meter mounted transfer switch162). For example, a current transformer in the generator168may determine the power being used by the electrical loads by measuring the amount of current flowing to the loads. The load management controller170may include each function of the load management controller described in the embodiment with reference toFIGS.3cand4, along with additional functions for power control of the switch assemblies (e.g., power management module164and/or meter mounted transfer switch162). The generator controller174may also or alternatively perform load control management at the generator168. The load management controller170may also act as the transfer switch controller and determines the position of the transfer switch to provide power to one or more electrical loads. The load management controller170may also be configured to connect the secondary power supply to one of the electrical loads (e.g., appliances166) after detecting a loss of power from a utility power supply. For example, the load management controller170instructs one of the transfer switches/relays in the power management module164to change to a second position during a power outage to connect generator168to the appliances166. In some embodiments, the generator controller174and the load management controller170are integrated together into a single controller positioned within the generator168. In other embodiments, the load management controller170is integrated in another position separately from the wireless gateway172. For example, the load management controller170may be integrated within the housing of the secondary power source (e.g., generator168). The load management controller170can communicate the controls for load shedding and the transfer switch over radio frequencies via the wireless gateway172that is electrically connected to the secondary power source (e.g., generator168, via the generator controller174). In some embodiments, the wireless gateway172may be hard-wired to the generator controller174via four wire RS485 cables. In some embodiments, the wireless gateway172uses a combination of WiFi and Zigbee protocols. In contemplated embodiments, the wireless gateway172is positioned outside the housing of the generator168(e.g., coupled to the outside of the housing). The wireless gateway172facilitates communication between the load management controller170and the wireless load switching device (e.g., power management module164). For example, the wireless gateway172sends instructions from the load management controller170to the power management module164for a transfer switch to change positions to disconnect the appliance166from the generator168. A network interface of the wireless gateway172connected to the secondary power source (e.g., electrically and communicably coupled to the generator controller174) may include, but is not limited to, a Wi-Fi interface, a cellular modem, a Bluetooth transceiver, a Bluetooth beacon, or a combination thereof. In other embodiments, the wireless gateway172includes different type of network devices to enable other kinds of cellular radio communications. In some embodiments, instead of using wireless radio communications via the wireless gateway172, the load management controller170sends and receives data via power line communications (PLC). As such, the load management controller170can transmit and receive information on load shedding and available power of the generator168over power communication lines (i.e., existing, hard-wired cables for utility power) installed between the load switching device, secondary power source, and the electrical loads (e.g., appliance166, electricity for a house, etc.). The wireless gateway172may communicate to a WiFi router in a home that is being powered by the generator168. As such, the wireless gateway172can relay information to the router on the amount of power available in the generator168, for example. In some embodiments, the wireless gateway172may communicate to the WiFi router that a backup power supply (e.g., generator168) is being used instead of a utility power supply. In some embodiments, the electrical load being powered by the generator168that is physically and electrically connected to the power management module164is an appliance166. Appliances166include types of machines that are powered by electricity from a home, such as a washing machine, a dryer, a dishwasher, etc. The wireless load switching device (e.g., the power management module164) can be installed at a lead of the appliance166. The appliance166may directly couple to the wireless load switching device (e.g., the power management module164) to receive power from the secondary power source (e.g., generator168). For example, contact jaws of the power management module164are structured to receive a connection interface, such as a wired plug, of the appliance166. The wired plug of the appliance166may include prongs that can insert into the contact jaws of the power management module164. In some embodiments, the prongs of the wired plug are structured the same as contact blades of the power management module164. The plug-in power management module164can transfer the power supplied to the appliance166between a metered utility power source and power from generator168upon detection, by the load management controller170, of a loss of power from the utility power source. In some embodiments, the wireless load switching device communicates, via the wireless gateway172, with the load management controller170and/or the generator controller174to determine when to change positions of a transfer switch. The wireless load switching device may communicate with the load management controller170to determine when to move the transfer switch between a first position and a second position to selectively disconnect one or more appliances166from a primary or secondary power supply (e.g., the generator168). This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular implementations. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable sub combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. It should be understood that while the use of words such as desirable or suitable utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” or “at least one” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. It should be noted that certain passages of this disclosure can reference terms such as “first” and “second” in connection with side and end, etc., for purposes of identifying or differentiating one from another or from others. These terms are not intended to merely relate entities (e.g., a first side and a second side) temporally or according to a sequence, although in some cases, these entities can include such a relationship. Nor do these terms limit the number of possible entities (e.g., sides or ends) that can operate within a system or environment. The terms “coupled” and “connected” and the like as used herein mean the joining of two components directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two components or the two components and any additional intermediate components being integrally formed as a single unitary body with one another or with the two components or the two components and any additional intermediate components being attached to one another. [OM] As used herein, the term “circuit” or “circuitry” may include hardware structured to execute the functions described herein. In some embodiments, each respective “circuit” may include machine-readable media for configuring the hardware to execute the functions described herein. The circuit may be embodied as one or more circuitry components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, etc. In some embodiments, a circuit may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (IC), discrete circuits, system on a chip (SOCs) circuits, etc.), telecommunication circuits, hybrid circuits, and any other type of “circuit.” In this regard, the “circuit” may include any type of component for accomplishing or facilitating achievement of the operations described herein. For example, a circuit as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, and so on). The “circuit” may also include one or more processors communicably coupled to one or more memory or memory devices. In this regard, the one or more processors may execute instructions stored in the memory or may execute instructions otherwise accessible to the one or more processors. In some embodiments, the one or more processors may be embodied in various ways. The one or more processors may be constructed in a manner sufficient to perform at least the operations described herein. In some embodiments, the one or more processors may be shared by multiple circuits (e.g., circuit A and circuit B may comprise or otherwise share the same processor which, in some example embodiments, may execute instructions stored, or otherwise accessed, via different areas of memory). Alternatively, or additionally, the one or more processors may be structured to perform or otherwise execute certain operations independent of one or more co-processors. In other example embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multi-threaded instruction execution. Each processor may be implemented as one or more general-purpose processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), or other suitable electronic data processing components structured to execute instructions provided by memory. The one or more processors may take the form of a single core processor, multi-core processor (e.g., a dual core processor, triple core processor, quad core processor, etc.), microprocessor, etc. In some embodiments, the one or more processors may be external to the apparatus, for example the one or more processors may be a remote processor (e.g., a cloud based processor). Alternatively, or additionally, the one or more processors may be internal and/or local to the apparatus. In this regard, a given circuit or components thereof may be disposed locally (e.g., as part of a local server, a local computing system, etc.) or remotely (e.g., as part of a remote server such as a cloud based server). To that end, a “circuit” as described herein may include components that are distributed across one or more locations. | 56,535 |
11862946 | DETAILED DESCRIPTION Example embodiments will now be described more fully with reference to the accompanying drawings. The cross-sectional view according toFIG.1shows an exemplary embodiment of a bus bar system1, which essentially consists of a contact protection housing4in which three bus bars2are accommodated. The bus bars2are accessible from the front of the housing4via contacting passages3, so that electrical devices and device adapters with hook-shaped retaining elements can engage behind the bus bars2via the contacting passages3after insertion. Analogous to the bus bar system known from WO 2017/182033 A1, the contacting of the bus bars can be provided via a separate contact element of the devices or device adapters, so that the retaining elements passing through the passages3and engaging behind the bus bars2actually only have a retaining function. Suitable single-pole contact terminals are also described, for example, in EP 3 258 558 B1. After the device or the component adaptor has been inserted into the housing4via the openings3through the upper part6of the housing, the device or the adaptor can be moved vertically downwards so that it engages behind the bus bars2. In the embodiment shown inFIG.1, the bus bar system has three poles and can thus be used, for example, for contacting three-pole component adaptors. The housing4essentially comprises the aforementioned upper part6and a lower part5, between which the bus bars2are accommodated, the upper part6being detachably connected to the lower part5. For this purpose, it is provided that the upper part6has, on its side facing the lower part5, a plurality of plug-in receptacles7extending from this side into the lower part5. The plug-in receptacles7are V-shaped or taper towards their free end and have openings permeable in the direction of advance x of the slider8. The slider8is inserted into the lower part5and has a plurality of catches9. In the representation according toFIG.1, the slider is arranged in the locking position in which the latching pawls9engage in the plug-in receptacle7and thus fix the upper part6to the lower part5. In contrast, in a release position in which the slider8is displaced upwards with respect to the position shown inFIG.1, the latching pawls9are located in front of the plug-in receptacles so that the upper part6can be lifted off the lower part5and thus the bus bars2are freely accessible and can be removed from the lower part5if necessary. The detents9point with their respective free end10in the direction of advance x of the slider8, along which the slider can be displaced from the release position to the locking position. The detents9are L-shaped and their shorter end is fixed to a straight slide plate12. This is shown in detail inFIG.4. The free end10of the detent pawls9is wedge-shaped, whereby the detent pawl9has a run-up slope11at its free end10which rises towards one of the shorter of the two sides of the L-shaped detent pawl9. In the release position of the slider8, the latch9rests via its rear side13facing away from the tip of the free end against an abutment surface14(seeFIG.1) of the lower part5, so that a precise definition of the release position of the slider8is provided. As shown inFIGS.2and3, when the slider8is displaced from the release position (FIG.2) to the locking position (FIG.3), it may abut against an outer surface18of the housing4via its abutment20, so that a precise definition of the locking position is also provided.FIGS.2and3further show that hook elements15may be provided to pre-fix the bus bars2to the lower part5when the upper part6is removed. For this purpose, after insertion of the bus bars2into the lower part5, the hook elements15can be engaged in corresponding snap-in receptacles24in the lower part5. The hook element15has a retaining blade17projecting beyond the bus bar2, which, when the upper part6is placed on the lower part5, can be positively received in one of the contacting passages3of the upper part6, so that the hook elements15are on the one hand precisely arranged and on the other hand do not increase the overall height of the bus bar system1. In an area between adjacent bus bars2, the upper part6has a recess21, the bottom22of which extends to a mounting side23(seeFIG.5) of the lower part5, by means of which the lower part5can be brought into contact with a support, for example a mounting plate. The upper part6and the lower part5each have a bore28, so that the upper part6can be connected to the lower part5and the support via a fastening means extending through the bores28in the base22and the mounting side23into the support. The contact protection housing4is of modular design and has complementary snap-in connectors26at the opposite longitudinal ends, which allow the bus bar system to be extended as desired. At the end, an end cap25is provided which covers the free ends of the bus bars2in a contact-proof manner. As shown inFIG.6, the plug-in receptacles7on the underside of the upper part6may be in the form of V-shaped bodies integrally moulded on the upper part6, the passage openings of which are aligned with one another and are permeable in the direction of advance x (compareFIG.1) of the slide8. Likewise, on the underside of the upper part6, the recesses21protrude beyond their bottom sides25with the bore28in order to reach the mounting side23of the lower part5when the upper part6is mounted on the lower part5(compareFIG.1). The features of the invention disclosed in the foregoing description, in the drawings as well as in the claims may be essential to the realization of the invention either individually or in any combination. The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. | 6,289 |
11862947 | DESCRIPTION OF REPRESENTATIVE EMBODIMENTS FIG.1shows a simplified perspective view of an X-ray inspection device R having a device housing G which rests on an underlying surface not shown in detail. The device housing G accommodates in the housing interior I (seeFIG.2) components of the X-ray inspection device R not shown in detail, which can include for example components such as an X-ray tube to which a coolant is applied, a chiller, a dehumidifier, a cooling device and associated tubes or hoses. In a depth direction Z, a switch cabinet S directly adjoins the device housing G to form an arrangement L. The switch cabinet S encloses a switch cabinet interior M (seeFIG.3) which is provided for accommodating electrical equipment not shown in detail, which is required for operating the X-ray inspection device R. In order to meet special safety requirements, the interior M of the switch cabinet S is hermetically separated from the housing interior I of the X-ray inspection device R. For this purpose, the switch cabinet S comprises a wall W forming the rear wall thereof, as illustrated inFIG.2. On a front side, remote from the wall W and accessible to operating personnel, the switch cabinet S is closed off by a switch cabinet door T, which is shown in a slightly opened position inFIGS.2and3and in a closed position inFIG.4. As illustrated particularly in the perspective view inFIG.3, the device housing G has a housing opening OG, through which the housing interior I is accessible, in the rear side of the device housing facing the switch cabinet S. To close off the housing opening OGand thus the housing interior I relative to the surroundings, the switch cabinet S is pivotable relative to the device housing G about a vertical pivot axis A as shown inFIG.3between an open position SOand a closed position SX. The switch cabinet S in the closed position SXis represented inFIGS.1and4whileFIGS.2and3show the switch cabinet S the open position SO. In the closed position, the wall W of the switch cabinet closes off the housing opening OGcompletely and hermetically such that, for example, liquid or gaseous coolant cannot penetrate through the housing opening OGinto the surroundings, especially into the switch cabinet S. The sealing is supported by a seal D which is provided at the rim of the housing opening OGin the device housing and runs completely around the periphery of the opening, which seal is pressed against by the wall W of the switch cabinet S when the switch cabinet is in the closed position. In the open position SOshown inFIGS.2and3, on the other hand, the housing interior I of the X-ray inspection device R is accessible (the open position SOshown is only selected for the sake of example). Although this position offers access to the housing interior I even with the small opening angle shown, this access can be further improved by further pivoting of the switch cabinet S away from the housing opening. Depending on how the linking of the switch cabinet S to the device housing G in the region of the pivot axis A is designed, the switch cabinet S can be pivoted from the closed position, even by more than 90°, to allow nearly unhindered access to the housing interior I. FIG.3also shows that the switch cabinet S has a switch cabinet opening OS, which leads into the switch cabinet interior M. The switch cabinet opening lies opposite the wall W of the switch cabinet and can be closed off by the switch cabinet door T. For that purpose, the switch cabinet door T is arranged on the frame of the switch cabinet S such that it can be pivoted relative to the frame of the switch cabinet S about the pivot axis A′ parallel to the pivot axis A. Both pivot axes A, A′ are on the same side of the arrangement L so that (in a view of the arrangement L from above) both the switch cabinet S and the switch cabinet door T thereof can each be pivoted counterclockwise in order to open the respective opening OG, OS. Alternatively it is also possible, however, to arrange the pivot axes alternately offset on the one and the other side of the arrangement L, for example, such that the opening movements take place alternately clockwise and counterclockwise. The housing opening OGof the X-ray inspection device R has the same dimensions as the switch cabinet opening OS. At the same time, the switch cabinet door T is designed to be fastened directly to the device housing G rather than to the frame of the switch cabinet, such that the housing opening OG—if the switch cabinet S can be forgone—can also be closed off with the switch cabinet door T transferred directly from the switch cabinet S to the device housing, rather than with the wall W of the switch cabinet S. The housing opening OGand the switch cabinet opening OSare designed identically for this purpose. The switch cabinet door T in this case could also be referred to as a system door because it can close off the device housing G or the switch cabinet S selectively, depending on the installation. Conversely, it is evident that a system door previously covering the housing opening OGcan be transferred instead to the front side of the switch cabinet S after interpolation of a switch cabinet S, in order to selectively close off or release the switch cabinet opening OS. It becomes clear fromFIGS.1to4that the device housing G can be modularly extended or reduced with the aid of the switch cabinet S in a simple manner. An X-ray inspection device R initially formed without a supplementing switch cabinet S can be easily re-equipped by arranging the switch cabinet S in the manner shown in order to move certain components from the housing interior I of the X-ray inspection device R into the adjoining switch cabinet S and thereby separate them from the housing interior. Instead of providing an autonomous switch cabinet to be positioned separately for this purpose, the switch cabinet S is arranged according to the invention on the device housing such that it separates the housing interior I by means of the wall W from the switch cabinet interior M in the closed position. The wall W fulfills a double function in this case, because it seals and separates both the housing interior and the switch cabinet interior. FIG.5shows a simplified representation of another embodiment within the scope of the present invention. A device housing G has been extended by a switch cabinet S in the manner already described. The arrangement composed of device housing G and switch cabinet S has been supplemented by two additional switch cabinets S1and S2. In the manner according to the invention, the switch cabinet S, by means of the wall W thereof, closes off the housing opening OGof the device housing G (although the covered openings or walls cannot be seen inFIG.5). The added switch cabinet S1closes off, by means of its rear wall, the switch cabinet opening of switch cabinet S in the manner of the invention, while the additionally added switch cabinet S2in turn closes off the switch cabinet opening of the first switch cabinet S1. The switch cabinet S2is closed off at the front side thereof by a switch cabinet door T. All the switch cabinets are pivotable relative to one another about a vertical pivot axis not shown in detail such that the switch cabinet interiors of the individual switch cabinets, or the housing interior I of the device housing, become accessible by pivoting aside the switch cabinets in front of the respective opening. As used herein, whether in the above description or the following claims, the terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, that is, to mean including but not limited to. Also, it should be understood that the terms “about,” “substantially,” and like terms used herein when referring to a dimension or characteristic of a component indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude variations therefrom that are functionally similar. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit. Any use of ordinal terms such as “first,” “second,” “third,” etc., in the following claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another, or the temporal order in which acts of a method are performed. Rather, unless specifically stated otherwise, such ordinal terms are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term). Rather than using an ordinal term to distinguish between commonly named elements, a particular one of a number of elements may be called out in the following claims as a “respective one” of the elements and thereafter referred to as “that respective one” of the elements. The term “each” may be used in the following claims for convenience in describing characteristics or features of multiple elements, and any such use of the term “each” is in the inclusive sense unless specifically stated otherwise. For example, if a claim defines two or more elements as “each” having a characteristic or feature, the use of the term “each” is not intended to exclude from the claim scope a situation having a third one of the elements which does not have the defined characteristic or feature. The above-described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the present invention. For example, in some instances, one or more features disclosed in connection with one embodiment can be used alone or in combination with one or more features of one or more other embodiments. More generally, the various features described herein may be used in any working combination. LIST OF REFERENCE CHARACTERS A, A′ Pivot axisD SealG Device housingI Housing interiorL ArrangementM Switch cabinet interiorOGHousing openingOSSwitch cabinet openingR X-ray inspection deviceS, S1, S2. . . Switch cabinetSOOpen positionSXClosed positionT Switch cabinet doorZ Depth directionW Wall of the switch cabinet | 10,557 |
11862948 | Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. DETAILED DESCRIPTION Fish sticks are used for running wire through walls, attics, floors, suspended ceilings, and cable trays. Fish sticks are commonly used in areas with poor or non-existent lighting. The fish sticks provided herein provide light for the user to facilitate their use in these poorly-lit areas. In one embodiment, the fish stick includes a light emitting component, such as a lighted tip, near the leading end of the fish stick. The lighted tip receives an attachment piece at the end of the fish stick to hold the wire being run and is configured to direct light around the attachment piece at the end of the fish stick. In another embodiment, the fish stick is made of a phosphorescent material and is stored in a container that charges the phosphorescent material to constantly be in condition for use. The container may include a light emitting component, such as an LED and reflective internal surfaces so that the rods of the fish stick are constantly absorbing energy from the LED. As a result, when the fish stick is assembled the rods emit phosphorescent light without requiring a charging period. In another embodiment, the fish stick is made of multiple rods that are threadably engaged with each other. The rods include a spring biasing element that increases the coefficient of friction between the rods, reducing the likelihood of the rods accidentally disengaging from each other while the fish stick is being manipulated. In another embodiment, the fish stick is made of multiple rods that are threadably engaged with each other via collars. The rods include two threaded surfaces that are outwardly-facing. The rods also include a collar with an inwardly-facing threaded surface that engages one of the outwardly-facing threaded surfaces. The rods also include an end with a protrusion and an end with a bore configured to receive the protrusion. When connected, a first rod's protrusion is placed within a second rod's bore, and the second rod's collar is rotated to engage both the first threaded surface of the first rod and the second threaded surface of the second rod at the same time, thus securing the engagement between the first and second rods. InFIGS.1-2, a worker is holding a fish stick10to drag cable C behind walls. Fish stick10includes lighted tip108and attachment piece188. Fish stick10includes a body portion14, a first end18, and an opposite second end22. The first end18has male threads24and the second end has female threads28. Threads24,28are preferably comprised of metal. The first end18and the second end22include stiffness indicia32,36to indicate the stiffness of the body portion14. In various embodiments, there may only be stiffness indicia32on the first end18, only be stiffness indicia36on the second end22, or both ends18,22may include stiffness indicia32,36. In some embodiments, the stiffness indicia32,36are different colors to indicate the different stiffness ratings of the body portion14. For example, red may be used to indicate high stiffness, yellow to indicate medium stiffness, and blue to indicate low stiffness (i.e., high flexibility). In some embodiments, the body portion14comprises a phosphorescent material (e.g., in a fiberglass resin included in body portion14), allowing the fish stick10to glow in the dark. In embodiments where only the first end18has stiffness indicia32, the phosphorescent material of the body portion14may extend to the second end22, such that the second end22is phosphorescent instead of having stiffness indicia36. Similarly, in embodiments where only the second end22has stiffness indicia36, the phosphorescent material of the body portion14may extend to the first end18, such that the first end18is phosphorescent instead of having stiffness indicia32. Traditional phosphorescent fish sticks do not have stiffness indicators. However, the described phosphorescent fish stick10allows an operator to easily discern the stiffness of a certain fish stick10by quickly glancing at the stiffness indicia32,26. In some embodiments, the body portion14of the fish stick10may include a reflective surface, as will be described later herein. In other embodiments, body portion14is at least partially wrapped (not shown) in a material (e.g., a sticker) that is made of a phosphorescent material. In these embodiments, body portion14itself may optionally also be made of a phosphorescent material. In still other embodiments, body portion14is at least partially wrapped in a material that protects users from body portion14breaking (e.g., from fiberglass splinters if body portion14comprises fiberglass and it is snapped). As shown inFIG.3, a plurality of fish sticks10may be linked together by consecutively mating the male threads24of fish sticks10with female threads28of adjacent fish sticks10. This consecutive linking arrangement40allows an operator to easily discern the stiffness of each individual fish stick10in the linked arrangement40. In the linked arrangement40, the first and second ends18,22with stiffness indicia32,36separate the phosphorescent body portions14of each fish stick10and, thus, allow the operator to easily count the number of body portions14, and, thus, the number of fish sticks10in line. As shown inFIGS.4-7, a lighted tip108may be attached to the fish stick10, as described below. The lighted tip108includes a housing112made of transparent plastic with an attachment end116having a cylindrical bore120and a light transmission end124with a cylindrical bore128. As shown inFIGS.5-6, the housing112is made of two pieces132,136that are secured together via respective threads140,144. Metal female threads148are located in the cylindrical bore120of the attachment end116and female threads152are located in the cylindrical bore128of the light transmission end124. The lighted tip108includes a light source such as an LED156, which transmits light out of the lighted tip108in the direction of the light transmission end124via a curved lens160. Curved lens160comprises outer surface168and inner surface172. Inner surface172axially surrounds and generally faces towards the primary longitudinal axis12of rod10, shown as a fish stick, and outer surface168generally extends from LED156to outer wall176of piece132and generally faces away from inner surface172. In one embodiment, at least a portion of inner surface172is arcuate-shaped and centered around primary longitudinal axis12of rod10. At least a portion of outer surface168is arcuate-shaped and centered around primary longitudinal axis12of rod10. As a result of the respective curves of inner surface172and outer surface168, at least a portion of light emitted from LED156towards outer wall176through curved lens160is refracted from its original path towards light transmission end124. Light emitted from LED156towards curved lens160curves, such as via refraction, around and through curved lens160, and out light emission wall180, which is generally perpendicular to longitudinal axis12of rod10, longitudinal axis110of lighted tip108, and longitudinal axis129of bore128. Trusses184extend diagonally from end126of first piece132to light emission wall180, providing structural support to both. In one embodiment, bore128is made of an opaque material, such as a metal alloy, and end130of bore128extends past end126of piece132. In other embodiments, lens160may have one or more flat sides and/or reflective material to redirect light towards light transmission end124. For example, outer surface168and inner surface172may have flat portions (i.e., non-curved portions). In these embodiments, lens160may include a reflective material (e.g., on outer surface168), to redirect light from LED156towards light transmission end124. Because the housing112is made of transparent plastic, the housing112also transmits light in directions besides towards the light transmission end124. The LED156is powered by batteries190. The LED156and batteries190are connected via circuit wire192and circuit toggle194when rod10is inserted into bore128, forcing circuit toggle194towards light unit sidewall164and closing the circuit with circuit wire192. When rod10is absent from bore128, spring196biases batteries190and circuit toggle194away from circuit wire192, thus opening the circuit and disengaging power to LED156. The LED156and/or batteries190are electrically connected to a circuit that includes the metal female threads148of the attachment end116. When mating metal threads, such as male threads24of fish stick10, threadably mate with the metal female threads148of the attachment end116, the circuit is completed and thereby powers on the LED156. In operation, a fish stick10with metal male threads24is threadably inserted into the cylindrical bore120. As shown inFIGS.4-7, the attachment end116is tapered to provide a smooth transition between the lighted tip108and the fish stick10. When the metal male threads24threadably mate with the metal female threads148, the circuit is completed, thereby turning on the LED156. The LED156now transmits light through lens160and housing112to illuminate the lighted tip108and an area in front of the light transmission end124. The fish stick10may be removed to break/open the circuit and thereby turn off the LED156as soon as threads24of fish stick10cease contact with the metal female threads148. Alternatively, while the fish stick10is still attached to the attachment end116and the LED156is turned on, a second fish stick10with male threads24may be inserted into the cylindrical bore128of the light transmission end124, and connected to the lighted tip108via threads24,152. As shown inFIGS.4and5, the light transmission end124is tapered to provide a smooth transition between the lighted tip108and the second fish stick10. While the second fish stick10is attached, the light transmission end124of the lighted tip108is designed to evenly scatter light such that, even with the second fish stick10(or other attachment such as a wisk or hook) threadably mated with the light transmission end124, the lighted tip108effectively transmits light in front of the light transmission end124. In other words, the optics of the lighted tip108are configured to bend light around the attached second fish stick10, to potentially illuminate an area contacted or surrounded by the second fish hook10. In the illustrated embodiment the threads148,152of the lighted tip108are female but in alternative embodiments, the cylindrical bores120,128can be omitted and instead of female threads148,152, protrusions can extend from ends116,124with male threads that are configured to threadably mate with the female threads28of fish stick10, completing/closing the circuit in the same manner as described above to turn on the LED156. In still other embodiments, threads148,152of the lighted tip108are male and threadably engage with corresponding female threads. As shown inFIGS.8and9, a container44may be provided to hold a plurality of fish sticks10. The container44includes an ultraviolet light (UV)48. In the illustrated embodiment, the UV light48is fixed to an internal surface52of the container44, but in other embodiments, the UV light48is separate from the internal surface52and is simply placed within the container44. Traditionally, operators store fish sticks in dark places, such as a truck, a box, or a bag. Thus, before the operator can use phosphorescent fish sticks, the operator must take the fish sticks out of the dark storage and put them under light, such as sunlight, and wait for the phosphorescent material to absorb the light energy, which is inconvenient and time consuming. However, when a plurality of fish sticks10are stored in the container44, the phosphorescent body portions14of the fish sticks10store energy absorbed from the UV light48. Then, when the fish sticks10are subsequently removed from the container44and used in a dark work area by the operator, the body portions14emit the stored energy in a form of visible light. Thus, when using the container44, the operator does not need to wait when ready to use the fish stick10with phosphorescent body portion14. Rather, the operator may simply take the fish stick10out of the container44and immediately use the fish stick10in a dark work area. The UV light48may also charge the phosphorescent body portion14faster than traditional methods, such as sunlight, because the UV light48is more concentrated. In some embodiments, the internal surface52is comprised of a reflective material to reflect the light from the UV light48within the container44. In such embodiments, each of the fish sticks10is able to absorb the UV light more easily, because the reflective material of the internal surface52disperses the light from the UV light more evenly and completely. In some embodiments, as described above, the body portions14of the fish sticks10may include reflective surfaces to more evenly disperse the light from the UV light48to fish sticks10that are bunched together. In some embodiments, the storage container44is a tube56with a fixed bottom60and a removable cover64. In some embodiments, the cover64can be a cap that is attached to the tube56via a lanyard68. The cover64includes an internal surface72with means such as hooks76for attaching fish stick tips80, such as lighted tips. Thus, as shown inFIG.9, an operator may store tips80in the cover64. In other embodiments, the storage container44may be a soft case or a box, such as a tool box. In some embodiments, as shown inFIG.8, the container44can include threads84on an outside surface88that interact with threads92of a storage piece96that is removably attached to the container44. Thus, as shown inFIG.9, the storage piece96can store fish tip accessories100, such as tips80or thread adapters when attached to container44. However, as shown inFIG.8, even when the storage piece96is removed from the container44, the fixed bottom60still functions as a closed surface to contain the fish sticks10stored within the container44. In some embodiments, one or more separators104, such as ribs or discs with holes, can be used to prevent the fish sticks10from resting on one another and/or the storage container44. In some embodiments, the separators104are included on the fixed bottom60. When the fish sticks10are stored in the container44, the separators104allow the light from the UV light48to more evenly and completely strike the phosphorescent body portions14of the fish sticks10in the container44. FIG.10illustrates a rod connector210that includes a male connector214and a female connector218. The rod connector210includes a male grip portion230located on the male connector214, and a female grip portion234located on the female connector218. The male and female grip portions230,234are graspable by an operator to maneuver or twist the male and female connectors214,218respectively. The rod connector210further includes rod bores222and226, each configured to receive an end portion of one or more elongated rod segments. Specifically, the male connector214includes a first rod bore222(FIG.13) located opposite a male stud238, and the female connector218includes a second rod bore226(FIG.14) located opposite a female bore242. The rod bores222and226can be elongated apertures having a shape and dimension that permits an end portion of each elongated rod segment to fit snugly within each rod bore222and226. The end portions of the rod segments can be secured within the rod bores222and226by adhesive, by press fit, by fasteners, or by any other securing means sufficient to keep the male and female connectors214,218affixed to the end portions of the rod segments. The male and female connectors214,218can also include chamfers224located adjacent the first and second rod bores222,226respectively. The chamfers224provide a smooth transition between the outer surfaces of the rod segments and the rod connector210, allowing an assembled rod to slide smoothly past obstacles during operation. With reference toFIG.11, the male connector214includes a male threaded portion246located on the male stud238. Likewise, the female connector218includes a female threaded portion250(FIG.14) located inside the female bore242, and corresponding to the male threaded portion246of the male connector214. The male connector214can be coupled to the female connector218by inserting the male stud238into the female bore242, and twisting the male connector214relative to the female connector218to engage the male threaded portion246with the female threaded portion250. With reference toFIGS.12and14-15, the rod connector210also includes a biasing member254disposed within the female connector218. The biasing member254is depicted as a coil spring inFIG.12; however, in other constructions, the biasing member254can be a flat spring, a disc spring, or any other type of biasing member capable of exerting a compressive force. The biasing member254is oriented axially within a spring bore266(FIG.14) located adjacent the female threaded portion250of the female bore242. In some constructions, the rod connector210can also include a set screw258disposed within the female connector218and having set screw threads262. In this construction, the female connector218can also include a spring bore threaded portion268located adjacent the second rod bore226, and engaging the set screw threads262to retain the set screw258within the female connector218. In this construction, the biasing member254can be pressed onto the end of the set screw258to secure the biasing member within the spring bore266. In other constructions, the set screw258can be replaced with a permanent fixture (not shown) within the female connector218. In operation, when the male connector214is threaded into the female connector218, the biasing member254contacts and exerts a compressive force against the male stud238(FIG.15). This compressive force increases the friction between the male and female threaded portions246and250of the male and female connectors214and218. The increased friction between the threaded portions246and250of the connectors214and218makes it more difficult to unscrew the male connector214from the female connector218. The compressive force exerted by the biasing member254against the male stud238increases the magnitude of the twisting force required to overcome the increased friction between the threaded portions246and250. This reduces the likelihood that the male and female connectors214,218become inadvertently unscrewed from one another while the assembled rod segments are twisted or otherwise maneuvered during operation. In some constructions, the magnitude of the compressive force exerted by the biasing member254against the male stud238can be adjusted by advancing or reversing the set screw258. Specifically, by advancing the set screw258toward the female threaded portion250of the female bore242, an axial distance D (FIG.15) within which the biasing member254must compress is decreased, and the resulting force exerted by the biasing member254against the male stud238is increased. Conversely, by reversing the set screw away from the female threaded portion250of the female bore242, an axial distance D within which the biasing member254must compress is increased, and the resulting force exerted by the biasing member254against the male stud238is decreased. In this manner, the amount of friction between the threaded portions246and250of the connectors214and218can be increased or decreased by adjusting the set screw258. An operator can position the set screw in such a manner as to strike a balance between the difficulty of twisting the rod segments together, and the potential for obstacles to inadvertently unscrew the rod segments during operation, depending on the particular conditions of the application. FIG.16illustrates a first fish stick310with a body314, a first end318, and an opposite second end322. The first end318has a first threaded surface324and a protrusion328. In an illustrative embodiment, the body314may include a rod comprised of fiberglass extending between the first end318and the second end322. As shown inFIG.17, a notch332extends radially outward from the protrusion328. The second end322has a second threaded surface336and a recess340. As shown inFIG.17by a second fish stick310′ that is identical to first fish stick310, a slot344′ extends radially outward from the recess340′. In the illustrated embodiment, the protrusion328is a cylindrical pin and the recess340is a cylindrical bore, but in other embodiments the protrusion328and recess340may take other shapes or forms. As shown inFIG.16, a collar348is threadably arranged in a first position about the second threaded surface336. Specifically, the collar348has a third threaded surface352that is threadably engaged with the second threaded surface336. As shown inFIGS.17and18, the first fish stick310may be mated with a second fish stick310′ by inserting the protrusion328of the first fish stick310into the recess340′ of the second fish stick310′. As shown inFIG.17, the notch332must be rotationally aligned with the slot344′. Otherwise, the recess340′ will not be able to receive the protrusion328. Although the embodiments shown inFIGS.17and18show the notch332and the slot344′, in alternative embodiments, any other suitable shape may be used to rotationally secure the first fish stick310to the second fish stick310′. For example, the notch332and the slot344′ may have a D shape, a crown shape, etc. Once the notch332is in the slot344′ and the protrusion328is in the recess340′, the first end318of the first fish stick310is mated with the second end322′ of the second fish stick310′. At this point, the first end318of the first fish stick310is not rotatable with respect to the second fish stick310′ because arrangement of notch332in slot344′ prevents relative rotation between the first fish stick310and the second fish stick310′. However, the first fish stick310and second fish stick310′ are still not secured together, because there is nothing to prevent the first end318from sliding axially out of the second end322′. Arrangement of notch332in slot344′ forces a specific rotational arrangement between the first end318and second end322′, in which the first threaded surface324of the first fish stick310is aligned with the second threaded surface336′ of the second fish stick310′, such that the first and second threaded surfaces324,336′ form a continuous threaded surface. Thus, the collar348′ may be moved from the first position (FIG.18) to a second position (FIG.19), in which the collar348′ threadably engages both the first threaded surface324of the first fish stick310and the second threaded surface336′ of the second fish stick310′, such that the first fish stick310and second fish stick310′ are secured together. Specifically, the first fish stick310is now prevented from being axially removed from the second fish stick310′ because the third threaded surface352′ is threaded onto both the first threaded surface324and second threaded surface336′. In other words, the collar348′ holds the first end318and second end322′ together in tension if the first fish stick310is attempted to be pulled from the second fish stick310′. Further, the first end318of the first fish stick310is prevented from rotating off the second end322′ of the second fish stick310′, with the collar348′ coupled to the first threaded surface324, because arrangement of notch332in slot344′ prevents relative rotation between the first end318and second end322′. The collar348′ also provides additional strength between the first end318and second end322′ when the first fish stick310is bent with respect to the second fish stick310′. If a user desires to separate the fish and second sticks310,310′, the user simply moves the collar348′ from the second position back to the first position, in which the collar348′ is only engaged with the second threaded surface336′ of the second fish stick310′. The user may now slide the first end318out of the second end322′. In the illustrated embodiment, the first fish stick310and second fish stick310′ are identical, but in other embodiments, the first fish stick310may have the first end318with the first threaded surface324, protrusion328and notch332, but the second end322may include different structure instead of the second threaded surface336, recess340and slot344. For instance, the second end322may include a whisk or hook (not shown). Likewise, in other embodiments, the second fish stick310′ may have the second end322′ with the second threaded surface336′, recess340′ and slot344′ but the first end318′ may include different structure instead of the first threaded surface324′, protrusion328′ and notch332.′ For instance, the first end318′ may include a whisk or hook (not shown). In other words, the second end322of the first fish stick310does not need to be identical to the second end322′ of the second fish stick310′ and the first end318′ of the second fish stick310′ does not need to be identical to the first end318of the first fish stick310, as shown inFIG.20. Although the disclosure has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the disclosure as described It should be understood that the figures illustrate the exemplary embodiments in detail, and it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for description purposes only and should not be regarded as limiting. Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present disclosure. Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more component or element, and is not intended to be construed as meaning only one. As used herein, “rigidly coupled” refers to two components being coupled in a manner such that the components move together in a fixed positional relationship when acted upon by a force. Various embodiments of the disclosure relate to any combination of any of the features, and any such combination of features may be claimed in this or future applications. Any of the features, elements or components of any of the exemplary embodiments discussed above may be utilized alone or in combination with any of the features, elements or components of any of the other embodiments discussed above. | 28,762 |
11862949 | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction and Environment As required, detailed aspects of the present invention are disclosed herein, however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure. Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning. II. First Embodiment Explosion-Proof Conduit Fitting2 FIGS.1-3show a first embodiment explosion-proof conduit fitting2, where a first fitting10and a second fitting12are filled with a removable gas tight compound22. The first and second fittings10,12are joined by a central joining conduit portion15filled with a granular material24, such as sand. The fittings10,12are also joined on their respective ends to another conduit section4,8containing conductors or cables6. The conductors or cables pass through the first fitting, the joining conduit, and the second fitting, before traveling through a second conduit section. The granular material24prevents explosions within the conduit fitting from damaging the conductors or cables and the conduit itself, and the gas-tight fill22within the two fitting elements10,12prevents explosive gasses from entering the fitting in the first place. Fill ports14with threaded caps16allow for filling of the fittings10,12once connected to the central joining conduit portion14to fill or remove the gas tight compound22. The caps16have external threads18and the fill ports14have internal threads20. The upper cap is used for filling the granular material24and gas tight compound22. III. Second Embodiment Explosion-Proof Conduit Fitting102 FIGS.4-7show a second embodiment explosion-proof conduit fitting102wherein the joining conduit of the first embodiment is incorporated into a single fitting110having two ends joined by a central portion. Here, the ends can again be filled with the gas-tight compound22or the entire interior of the fitting110can be filled with a granular compound124and gas tight compound122as shown inFIG.7. This embodiment removes the need for the central joining conduit portion ofFIG.1. As shown, this embodiment utilizes the same fill port14and cap16elements as the first embodiment, but any suitable fill port and cap arrangements could be utilized. In a preferred embodiment, the gas-tight compound122is added to the bottom port of the fitting102, after which the granular material124is added in the top port, after which the final portion of gas-tight compound is added on top. IV. Third Embodiment Explosion-Proof Conduit Fitting202 FIGS.8-11show a third embodiment explosion-proof conduit fitting202similar to the previous embodiment102having a single fitting210.FIG.11shows a cross-sectional view of how the two ends of the fitting210are filled with a gas tight material222and the central portion is filled with a granular material224. The granular material is added to the center portion through a pair of ports214having external threads220with the cap216having interior threads218. This prevents the granular material224from interfering with the threads as would occur with interior threads used in the other port14and cap16arrangement.FIG.11also shows internal ridges232and/or grooves234within the fitting210which help to provide additional frictional force against the granular material224, increasing its explosion-proof capabilities. An optional fiber backing226is placed on each end of the fitting210to stop the migration of the gas tight compound222. V. Fourth Embodiment Explosion-Proof Conduit Fitting302 FIGS.12and13show a fourth embodiment explosion-proof conduit fitting302formed from a first fitting310and a second fitting312. The first fitting310is shown connecting to a conduit4using a threaded connector312, although any connection type may be used. The two fittings are connected via internal threads328located inside of a flared-out end of the first fitting310and external threads330of the second fitting312, however this is merely one example of how the fittings310,312could be joined. A gas tight compound322fills the second fitting312, while a granular material324fills the first fitting310. This configuration can be filled without filling ports by disassembling the coupling and pieces and sliding the pieces up or down, or sideways, to provide access to fill the fittings with granular fill and vapor tight foam. This configuration also shows a threaded connector314which can threadedly connect the first fitting310to the conduit section4via internal threads318on the threaded connector314and external threads320on the conduit section4. The pieces and elements described herein can be manufactured from malleable iron rather than casting, which can allow more economical construction. It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects. | 5,836 |
11862950 | DETAILED DESCRIPTION The details of one or more aspects of cable duct assemblies and cable duct assembly components are described in this disclosure. Cable duct assemblies and cable duct assembly components made in accordance with this disclosure have particular application in open environments, electrical cabinets, and electrical panels to protect, route, and organize cables, particularly in applications that are in hard-to-reach or confined spaces in which the cables require protecting. A first cable duct assembly100is illustrated inFIGS.1A-6C, a second cable duct assembly200is illustrated inFIGS.7A and7B, and a third cable duct assembly300is illustrated inFIGS.8A,8B,8C,8D, and9. These Figures illustrate a cable duct assembly that includes a cover plate arranged opposite a base plate and a pair of sidewalls arranged opposite one another. For example,FIGS.1A-6Cillustrate a cable duct assembly100, which includes a cover plate110arranged opposite a base plate130and a pair of sidewalls150arranged opposite one another (e.g., a first sidewall151arranged opposite a second sidewall172). The base plate130forms the base of the cable duct assembly100. The base plate130may define at least one sidewall connector (e.g., sidewall connector132, sidewall connector142) that is configured for connecting with a sidewall150(e.g., first sidewall151, second sidewall172). For example, in the first cable duct assembly100, a first sidewall connector132and a second sidewall connector142are illustrated, where the first sidewall connector132is spaced apart from and generally parallel to the second sidewall connector142. In the first cable duct assembly100, the first sidewall connector132engages with (e.g., snaps into) the first sidewall151, and the second sidewall connector142engages with the second sidewall172. The sidewall connector may include an inner base rail138,144spaced apart from an outer base rail140,146to define an open-ended locking channel that is configured for receiving a sidewall stem of a sidewall therein. For example, as illustrated inFIG.2B, the sidewall connector132may include an inner base rail138spaced apart from an outer base rail140to define an open-ended locking channel134that is configured for receiving the sidewall stem152of a sidewall151therein. As illustrated inFIG.2B, the inner base rail138may include an inner locking flange139that extends into the locking channel134, and the outer base rail140may include an outer locking flange141that extends into the locking channel134. The base plate130may include a base extension148,149that extends past the distal side of the sidewall connector (e.g., first sidewall connector132, second sidewall connector142). The base extension148,149stiffens the outer base rail (e.g., outer base rail140, outer base rail146) in relation to the base plate130, thereby preventing the outer base rail from rotating about the edge of the base plate130. For example, inFIG.8D, the load on the sidewall150results in the outside of the sidewall stem152and/or the outside of the lower portion of the sidewall150contacting and applying a force to the outer base rail140that is translated (transferred) to the base extension148and to the connected surface8. During such a situation, while the outside locking recess170may move out of engagement with the outer locking flange141, the inside locking recess168remains engaged with the inner locking flange139and the sidewall stem152is retained within the locking channel134, that results in the maintenance of the connection between the sidewall stem152and the sidewall connector132. The cable duct assembly100may include one or more pivot connections (e.g., first pivot connection133, second pivot connection135) that pivotally connect a sidewall to a respective sidewall connector. For example, as illustrated inFIGS.4and8A, through the interaction between the sidewall stem (e.g., sidewall stem152) inserted into the sidewall connector (e.g., first sidewall connector132), the inside locking recess168receives the inner locking flange and the outside locking recess170receives the outer locking flange141, as illustrated inFIG.2B, and the sidewall is able to pivot at its attachment with the base plate130, as illustrated inFIG.8B. As a result of the load exerted on the lower sidewall, illustrated inFIG.8A, the cable duct assembly300moves as a four-bar linkage, with rotation at the first hinge mechanism111and the second hinge mechanism, and that pivots at the first pivot connection133and the second pivot connection135. As illustrated inFIG.8D, the load on the first and second arms of the sidewall151may cause rotation of the first pivot connection133, which brings the snap reinforcement192into contact with the inner locking flange139, thereby locking the sidewall stem152within the sidewall connector132of the base plate130. The base plate130is configured for attaching to a surface8, as illustrated inFIG.8A. WhileFIG.8Aillustrates a vertical wall surface, in other aspects the surface may be differently oriented. InFIG.8A, a plurality of fasteners137are inserted through slots136(illustrated inFIG.2A) to attach the base plate130to the surface8. The cable duct assembly100further includes a plurality of sidewalls150arranged opposite one another (e.g., a first sidewall151arranged opposite a second sidewall172), as illustrated inFIG.2A. The sidewalls150are configured to connect between the base plate130and the cover plate110. When connected with the base plate130, the sidewalls150define a passageway102that is configured for receiving one or more elongated objects, such as cables2, therein. FIG.1Aillustrates a pair of sidewalls150(e.g., first sidewall151, a second sidewall172) andFIG.3is a side view of a sidewall150of a cable duct assembly100. In configurations, the sidewall150connects the base plate130to the cover plate110and is located between the base plate130and the cover plate110. A sidewall150may include a sidewall stem that is configured for connecting with a base plate130at a sidewall connector (e.g., first sidewall connector132, second sidewall connector142) and at least one arm. A sidewall150may include at least one first arm (e.g., first arm154, first arm155) and at least one second arm (e.g., second arm174, second arm175). The sidewall stem (e.g., sidewall stem152, sidewall stem171) may include a distal end that is configured for receipt into a locking channel (e.g., locking channel134of a first sidewall connector132, locking channel143of a second sidewall connector142). At least one arm (e.g., first aim154, second arm174) extends from the sidewall stem of the sidewall150. The sidewall150may include at least one first arm and at least one second arm. For example, the first sidewall151illustrated inFIG.1Aincludes a plurality of first arms154and a plurality of second arms174. A sidewall150may include a plurality of first arms and a plurality of second arms that are arranged in a pattern of alternating positions along a length of the sidewall stem, such as is illustrated inFIGS.1A,2A, and3. In other aspects, at least one of the sidewalls150may include any combination and order of first arms154and second arms174along a length of the sidewall stem. The second sidewall172may include a plurality of first arms and a plurality of second arms, as is illustrated inFIG.1. The second sidewall172may include a plurality of first arms and a plurality of second arms that are arranged in a pattern of alternating positions along a length of the sidewall stem171, such as is illustrated inFIG.1. The first arms and second arms may be positioned in any combination and/or order along the length of the sidewall stem171. While in aspects, the first sidewall151and the second sidewall172may be configured differently, in the cable duct assembly100illustrated inFIGS.1A,2A, and3, the first sidewall151and second sidewall172are generally identical to one another and, as positioned in the base plate130, are mirror images of each other. As such, a description of features of the first sidewall151can be extended to equivalent features on the second sidewall172. The sidewalls150are configured for pivotal connection with the base plate130. The first sidewall151may be configured to pivotally connect with the base plate130through a first pivot connection133, and the second sidewall172is configured to pivotally connect with the base plate130through a second pivot connection135. The sidewalls150are configured to hingedly connect with the cover plate through hinge mechanisms. The first sidewall151may be configured to hingedly connect with the cover plate110at a first side124through a first hinge mechanism111, and the second sidewall172is configured to hingedly connect with the cover plate110at a second side126through a second hinge mechanism121. As illustrated inFIG.3, the first arm154extends from a top side of the sidewall stem152to a first arm end156. The first arm end156may include a lobe mechanism158(also illustrated inFIGS.6A-6C) that is configured for rotational connection with a first saddle channel112of the cover plate110to form a first hinge mechanism111. As illustrated inFIGS.6A-6C, the first lobe mechanism158includes a rounded outer lobe portion160and a rounded inner lobe portion162. The rounded outer lobe portion160is configured to rotatably engage the first saddle channel112and to releasably secure the cover plate110to the sidewall150. As illustrated inFIG.6B, the rounded outer lobe portion160may include a first radius R2, and the rounded inner lobe portion162may include a second radius R1. In aspects, the first radius R2is greater than the second radius R1. This difference in radii allows, in a first configuration (e.g., the configuration illustrated inFIG.5C) the rounded outer lobe portion160to be inserted into the saddle channel112and then permits, in a second configuration, the rounded outer lobe portion160to rotatably engage the saddle channel112. The first lobe mechanism158may further include a detent step164(anti-rotation detent) defined intermediate the rounded outer lobe portion160and the rounded inner lobe portion162, as illustrated inFIG.6B. The detent step164is configured to engage a socket projection119defined in the second flange116of the first saddle channel112, and thereby prevent over-rotation of the cover plate110relative to the first arm154beyond an angular limit (e.g., 90°), for example as illustrated inFIG.6A. The second arm174extends from the top side of the sidewall stem152to a second arm end. The second arm174may include a rotation limiter178that is configured to engage the first saddle channel112of the cover plate110. The rotation limiters178may include a catch portion190,191that are free-floating in a first mode and are configured, in a second mode, to engage the first saddle channel112and limit rotation of the first saddle channel112relative to the rotation limiter178and the arm. In aspects, such as is illustrated inFIG.5B, the rotation limiters178are generally C-shaped, having a front jaw180and a rear jaw182. A recess184is defined between the front jaw180and the rear jaw182. The first flange114may include a cover hook portion115that extends into the saddle socket118. The front jaw180is configured for receipt into the saddle socket118, and the recess184is configured to receive the cover hook portion115therein. As a result, the rotation limiter178is configured to engage the saddle socket118at the cover hook portion115to limit the rotation of the first saddle channel112relative to the rotation limiter178and the arm. The second arm174may also include an inwardly extending deflector portion186that extends into the passageway102. The deflector portion186extends into the passageway102farther than the inward side166of the first arm154extends so that when the cable duct assembly100is mounted in a horizontal orientation, the deflector portion186is configured to receive a load from the cable2, whereas the first arm154does not so contact cable3. The arms (e.g., first arm154, second arm174) may include a break-off point near the base plate130for routing cables4through a sidewall150.FIGS.3,7A, and7Billustrate that at least one of the first arm154or the second arm174includes break-off points (e.g., score line) at or adjacent the connection between the respective arm and the sidewall stem152. For example, inFIG.3, a first arm154is illustrated as having a break-off point194defined at the connection between the first arm154and the sidewall stem152, and the second arm174is illustrated as having a break-off point196defined at the connection between the second arm174and the sidewall stem152. In aspects, the break-off points (e.g., break-off point194, break-off point196) may include a chamfered neck, for allowing the arm to be easily twisted off and removed from the sidewall stem, and to provide an additional space for cables to run through the sidewall, for example, as illustrated inFIGS.7A and7B. When an arm is twisted off in such a fashion when the sidewall150is installed on the base plate130by insertion of the sidewall stem152into the sidewall connector132, the break-off point is located below the top of inner base rail138and outer base rail140, leaving no material sticking up (e.g., a sharp vestige) above the base rails that could catch on and/or damage cables routed through the sidewall, as illustrated inFIGS.7A and7B. The sidewall150may include one or more nodules128that extend from an inside surface212. The nodules128are configured for receipt into the upper portion210of the sidewall connector (e.g., sidewall connector132). The nodules128are configured to keep the sidewall150perpendicular to the base plate130(e.g., when horizontally mounted). As illustrated inFIG.1A, the sidewall stem152may include at least one of a snap reinforcement192on a first side of the sidewall stem152and a snap cutout198on a second side of the sidewall stem152. During sidewall stem insertion into a sidewall connector, friction may occur between the rails (e.g., inner base rail, outer base rail) of the sidewall connector and the wall stem. In the cable duct assembly100, the sidewall stem (e.g., sidewall stem152) is configured to be inserted into the sidewall connector (e.g., first sidewall connector132) so that the inside locking recess168receives the inner locking flange and the outside locking recess170receives the outer locking flange141, as illustrated inFIG.2B. Through such a configuration, the insertion force required due to friction is minimized due to the small surface contact area. A sidewall150may include at least one snap reinforcement192on the first side of the sidewall stem152directly opposite a snap cutout198on the second side of the sidewall stem152.FIG.1Aillustrates four snap reinforcements192along the sidewall stem152and four snap cutouts198on the second side of sidewall stem171. The snap reinforcements and/or snap cutouts help maintain snap strength after multiple sidewall150insertions and extractions from a sidewall connector. The snap reinforcement192defines an inside locking recess168, and the opposite side of the sidewall stem152defines an outside locking recess170. The inside locking recess168is configured to engage the inner locking flange139, and the outside locking recess170is configured to engage the outer locking flange141when the sidewall stem152is inserted into the locking channel134. Such a connection defines the pivot connection (e.g., first pivot connection133, second pivot connection135) described herein. The cover plate110is configured to attach to the sidewalls150and to enclose the passageway102, as illustrated inFIG.4. In such a configuration, one or more objects (e.g., cables2,3) are retained within the passageway102of the cable duct assembly100. As illustrated inFIGS.1A-6C, the cover plate110has a first side124and a second side126. The cover plate110may include at least one saddle-shaped hinge feature, hereinafter referred to as the saddle socket, that is configured to engage a sidewall150at a sidewall arm end. For example, in the cable duct assembly100illustrated inFIG.2A, the cover plate110includes a pair of saddle sockets (e.g., first saddle socket118, second saddle socket120). The first saddle socket118may extend along an underside of the cover plate110is disposed adjacent a first distal edge of the cover plate110and the second saddle socket120extends along the underside of the cover plate110is disposed adjacent a second distal edge of the cover plate110. The first saddle socket118is configured to engage the first sidewall151at a plurality of first arm ends156and second arm ends176, and the second saddle socket120is configured to engage the second sidewall172at a plurality of first arm ends157and second arm ends177. As is illustrated inFIGS.1A,2A, and4, the saddle sockets (e.g., first saddle socket118, second saddle socket120) may generally be identical to one another and, as positioned connected to the cover plate110, may be mirror images of each other. As illustrated inFIG.1B, a saddle socket (e.g., saddle socket118) may include an elongated first flange114(first flange114) and an elongated second flange116(second flange116). An elongated saddle channel112is defined between the first flange114and the second flange116. The saddle socket118may extend along at least a portion of the length of the cover plate110, as illustrated inFIG.1AandFIG.2A. The first saddle channel112may be configured to rotatably receive a plurality of lobe mechanisms158of the first arm ends156, and a plurality of rotation limiting portions (e.g., rotation limiters178) defined on the second arm ends176. The lobe mechanism158is configured to rotatably engage a saddle socket (e.g., saddle socket118). The lobe mechanism158may be configured so that a portion of the lobe mechanism158is received between the first flange114and the second flange116and into the saddle channel112. The first saddle channel112may be configured to snap into place on the lobe mechanisms158, and the lobe mechanisms158may retain the cover plate110on the cable duct assembly100when the cable duct assembly100is installed on a connected surface8, such as is illustrated inFIG.8A. In aspects, the lobe mechanisms158allow the cover plate110to rotate to 90° (as illustrated inFIG.5A). As illustrated inFIG.6B, the second flange116may further include a socket projection119that is configured to engage the detent step164, described herein. The saddle socket118may be configured to connect with at least one arm end (e.g., first arm end156, second arm end176) of a sidewall150to form a hinge mechanism (e.g., hinge mechanism111, hinge mechanism121) that pivotally connects the cover plate110to a sidewall150. For example, as illustrated inFIG.2AandFIG.4, the saddle socket118is configured to receive first arm ends156of first arms154and second arm ends176of second arms174of a first sidewall151to form a first hinge mechanism111. The cover plate110is configured to rotate relative to a connected first sidewall151through the first hinge mechanism111when the cover plate110is detached from a second sidewall. Likewise, the cover plate110is configured to rotate relative to a connected second sidewall172through a second hinge mechanism121when the cover plate110is detached from the first sidewall151. The saddle channel112may further include a guide ramp117, for example, that extends from the second flange116. The guide ramp117is configured to align at least one of the lobe mechanism158or the rotation limiter178for insertion into the saddle channel112during the installation of the cover plate onto a first sidewall and/or when closing the cover plate on a second sidewall, as illustrated inFIG.5C. For example, as the cover plate110is brought into connection with the first aim ends156of the first arms154and second arms174of a sidewall150, the guide ramp117guides the lobe mechanism(s)158and/or the rotation limiter(s)178towards the saddle channel112, to enable the cover plate110to “snap” onto the lobe mechanism(s)158. In a cover-closed configuration (illustrated inFIG.4), the cover plate110is hingedly connected, at a first side124and a second side126, to a first sidewall151and a second sidewall172through a second hinge mechanism121. In the cover-closed configuration, the first sidewall151and the second sidewall172are also pivotally connected to the base plate130at a first sidewall connector132and a second sidewall connector142. In such a configuration, the cover plate110is able to move, relative to the first sidewall151, second sidewall172, and the base plate130, through the hinged and pivot connections, as will be described in greater detail herein. The lobe mechanisms (e.g., lobe mechanism158) on the arm ends retain the cover plate110when the passageway102of the cable duct assembly100is loaded with objects (e.g., cables2,3). FIG.2Aillustrates a pair of sidewalls150(e.g., first sidewall151, second sidewall172) connected to the base plate130, and the cover plate110is hingedly connected to a sidewall150(e.g., the first sidewall151) through the first hinge mechanism111. In such a cover-open configuration (illustrated inFIGS.2A,5A, and6A), the cable duct assembly100defines a passageway102that is configured to receive one or more cables2(illustrated inFIG.8A) or other objects therein. In the cover-open configuration, the cover plate110is configured to rotate about the first saddle channel112and/or the second saddle channel122to allow access to objects (e.g., cables2(illustrated inFIGS.8A,8C, and8D)) stored within the passageway102. In the cover-open configuration (illustrated inFIGS.2A,5A, and6A), the cover plate110is configured to pivot at the first side124about the first sidewall151, when a second side126of the cover plate110is detached from the second sidewall172. For example,FIG.2Aillustrates the first side124of the cover plate110attached to a first sidewall151but detached from a second sidewall172. In such a configuration, a cable2(illustrated inFIG.8A) or another object can be inserted into the passageway102defined through the cable duct assembly100. FIG.2Aillustrates a first hinge mechanism111.FIG.4is an end view illustration of the first cable duct assembly100that illustrates a pair of sidewalls150(e.g., first sidewall151, second sidewall172) connected to the base plate130. InFIG.4, the cover plate110is hingedly connected to the first sidewall151through the first hinge mechanism111, and the cover plate110is hingedly connected to the second sidewall172through a second hinge mechanism121. The hinge mechanisms are formed by the hinged connection between a saddle socket and the arm ends of a sidewall. In aspects, such as is illustrated inFIGS.1A,2A, and4, the hinge mechanisms (e.g., first hinge mechanism111, second hinge mechanism121) may generally be identical to one another and, as positioned in the cable duct assembly100, may be mirror images of each other. The first hinge mechanism111may include the first saddle channel112of the saddle socket118, and the second hinge mechanism121may include the second saddle channel122of the second saddle socket120. In other aspects, the first saddle channel112is spaced apart from and generally parallel to a second saddle channel122. The first saddle channel112may extend along a length of the cover plate110adjacent a first side of the cover plate110and the second saddle channel122may extend along the length of the cover plate110adjacent a second side of the cover plate110. The first saddle channel112and the second saddle channel122may be substantially identical and symmetrical. The first saddle channel112and the second saddle channel122may be disposed on opposed distal edges of the cover plate110. The first saddle channel112may be configured to snap onto a lobe mechanism158of a sidewall150(e.g., first sidewall151). A saddle channel (e.g., first saddle channel112) can be unsnapped from a mating lobe mechanism (e.g., lobe mechanism158) to allow the opening of the cover plate110, which permits the cover plate110to pivot about the opposing saddle channel (e.g., second saddle channel122) that remains attached to the other lobe mechanism on the opposing sidewall (e.g., second sidewall172) when the saddle channel (e.g., first saddle channel112) is unsnapped. The base plate130and the sidewalls150may be separate components, or they may be integrally formed. As is illustrated inFIGS.1A,2A, and4, the sidewalls150(e.g., first sidewall151, second sidewall172) may generally be identical to one another and, as positioned in the base plate130, may be mirror images of each other. FIGS.8A,8B,8C, and8Dillustrate a third cable duct assembly300horizontally installed onto a connected vertical surface8(connected surface8). In such a configuration, the base plate130is attached to the connected surface8. The cable duct assembly300is illustrated as holding a plurality of cables2,3. These Figures illustrate the respective load exerted by the cables2,3on the lower sidewall151, which causes tension between the cover plate110and the sidewall151, causing the catch portions190of the rotation limiters178on second arms174to engage the cover hook portion115of the saddle socket118, mechanically locking the sidewall151to the cover plate110. In aspects, this action further causes a movement (rotation) of the cover plate110relative to the first hinge mechanism111and the second hinge mechanism121. As illustrated inFIG.8B, the rotation of the cover plate110relative to the first hinge mechanism111causes the rotation limiter179of an upper second arm175to move into engagement with the cover hook portion113of the second saddle socket120and prevents further rotation of the second hinge mechanism121. As illustrated inFIG.8D, the load on the first and second arms of the sidewall151may cause rotation of the first pivot connection133and brings the snap reinforcement192into contact with the inner locking flange139, thereby locking the sidewall stem152within the sidewall connector132of the base plate130. As illustrated inFIG.8C, one or more of the cables (e.g., cable3), may bear against the deflector portion186of a second arm174, which causes the rotation limiters178to move into engagement with the cover hook portion115of the saddle socket118(as illustrated inFIG.9). As a result, the rotation limiter178locks onto the cover hook portion115and prevents further rotation of the first hinge mechanism111. As a result of the load exerted on the lower sidewall151, the cable duct assembly300moves as a four-bar linkage, with rotation at the first hinge mechanism111and the second hinge mechanism121, and pivots at the first pivot connection133and the second pivot connection135. Through such movement, the cable duct assembly300is able to handle the load of the cables2without the cover plate110detaching or without either of the sidewall stems detaching from its respective sidewall connector. InFIG.8D, the load on the sidewall151may further cause the outside of the sidewall stem152and/or the outside of the lower portion of the sidewall150to contact and apply a force to the outer base rail140that is translated (transferred) to the base extension148and to the connected surface8. During such a situation, while the outside locking recess170may move out of engagement with the outer locking flange141, the inside locking recess168remains engaged with the inner locking flange139and the sidewall stem152is retained within the locking channel134, that results in the maintenance of the connection between the sidewall stem152and the sidewall connector132through pivot connection133. The foregoing is considered as illustrative only of the principles of cable duct assemblies, including components therefor. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit a cable duct assembly to the exact construction and operation illustrated and described. While the preferred embodiment has been described, the details may be changed without departing from the cable duct assemblies described. The examples presented herein are directed to cable duct assemblies, and components thereof configured to retain electrical wiring. However, other embodiments of the cable duct assembly may be envisioned that are adapted for use with fiber optic cables, pneumatic lines, hydraulic lines, or a combination of any of these. Cable duct assemblies contemplate the assembly of various cooperating components fabricated from molded or extruded resilient materials, such as an elastomeric polymer, preferably polyvinyl chloride (PVC). Examples The following are additional examples of cable duct assemblies and components thereof. Example 1. A cable duct assembly that defines a passageway for retaining an elongated cable. The cable duct assembly includes a cover plate, a base plate, a first sidewall, and a second sidewall. The cover plate defines a first saddle socket spaced apart from and generally parallel to a second saddle socket. The base plate is arranged opposite the cover plate. The base plate defines a first sidewall connector. The first sidewall connects between the base plate and the cover plate. The first sidewall includes a first sidewall stem, a plurality of first arms configured to extend from the first sidewall stem to first arm ends, and a plurality of second arms configured to extend from the first sidewall stem to the second arm ends. The first sidewall stem is configured to be received into the first sidewall connector. The first arm ends include first lobe mechanisms that include first rounded outer lobe portions that rotatably engage the first saddle socket and releasably secure the cover plate to the first sidewall. The second arm ends include first rotation limiters. The first rotation limiters include first catch portions configured to engage the first saddle socket. The first catch portions limit rotation of the first saddle socket relative to the first rotation limiters. The second sidewall connects between the base plate and the cover plate. Example 2. The cable duct assembly of Example 1, wherein the first arms and the second arms are arranged in a pattern of alternating positions along a length of the first sidewall stem. Example 3. The cable duct assembly of Example 1, wherein the first arms further include a rounded inner lobe portion. The rounded outer lobe portion includes a first radius and the rounded inner lobe portion includes a second radius. The first radius is greater than the second radius. At least one of the first lobe mechanisms further include a detent step defined intermediate the rounded outer lobe portion and the rounded inner lobe portion, the detent step configured to prevent over-rotation of the cover plate relative to the first arms beyond an angular limit. Example 4. The cable duct assembly of Example 1, wherein the base plate further defines a second sidewall connector spaced apart from and generally parallel to the first sidewall connector. The second sidewall includes a second sidewall stem, a plurality of third arms configured to extend from the second sidewall stem to third arm ends, and a plurality of fourth arms configured to extend from the second sidewall stem to fourth arm ends. The second sidewall stem is configured to be received into the second sidewall connector. The third arm ends include second lobe mechanisms. The second lobe mechanisms include second rounded outer lobe portions configured to rotatably engage the second saddle socket and that releasably secure the cover plate to the second sidewall. The fourth arm ends include second rotation limiters. The second rotation limiters include second catch portions configured to engage the second saddle socket and limit rotation of the second saddle socket relative to the second rotation limiters. Example 5. The cable duct assembly of Example 4, that further includes at least one of: the first arms and the second arms alternating along a length of the first sidewall stem; or the third arms and the fourth arms alternating along a length of the second sidewall stem. Example 6. The cable duct assembly of Example 4, wherein the first rounded outer lobe portion includes a first radius, the first arms further include a rounded inner lobe portion, and the rounded inner lobe portion includes a second radius. At least one of the second lobe mechanisms further include a detent step defined intermediate the rounded outer lobe portion and the rounded inner lobe portion, the detent step configured to prevent over-rotation of the cover plate relative to the third aims beyond an angular limit. Example 7. The cable duct assembly of Example 1, wherein the first saddle socket includes a first saddle channel between a first flange and a second flange. Example 8. The cable duct assembly of Example 7, that further includes a guide ramp that extends from the second flange. The guide ramp configured to align at least one of the first arms or second arms for insertion into the first saddle socket. Example 9. The cable duct assembly of Example 7, wherein the first flange further includes a cover hook portion that extends to the first saddle channel. Example 10. The cable duct assembly of Example 9, wherein at least one of the first rounded outer lobe portions includes a first radius, wherein the first arms includes a rounded inner lobe portion, and wherein the rounded inner lobe portion includes a second radius. The first radius is greater than the second radius. At least one of the first lobe mechanisms further include a detent step defined intermediate the first rounded outer lobe portion and the rounded inner lobe portion. The detent step is configured to prevent over-rotation of the cover plate relative to the first arms beyond an angular limit. The second flange further includes a socket projection configured to engage the detent step. Example 11. The cable duct assembly of Example 9, wherein the first rotation limiters are generally C-shaped, the first rotation limiters include a front jaw and a rear jaw, and a recess is defined between the front jaw and the rear jaw. The front jaw is configured for receipt into the first saddle channel with the recess configured to receive the cover hook portion therein. The first rotation limiters are configured to engage the first saddle socket at the cover hook portion to limit rotation of the first saddle socket relative to the first rotation limiters. Example 12. The cable duct assembly of Example 1, wherein the second arms further include deflector portions configured to extend into the passageway. When the cable duct assembly is mounted in a horizontal orientation, the deflector portions receive a load from the elongated cable and transfer the load to the cover plate. Example 13. A cable duct assembly that defines a passageway configured to retain an elongated cable. The cable duct assembly includes a cover plate, a base plate, a first sidewall, and a second sidewall. The cover plate defines a first saddle socket spaced apart from and generally parallel to a second saddle socket. The base plate is arranged opposite the cover plate. The base plate defines a first sidewall connector and a second sidewall connector spaced apart from and generally parallel to the first sidewall connector. The first sidewall connects between the base plate and the cover plate. The first sidewall includes a first sidewall stem, a plurality of first arms configured to extend from the first sidewall stem to first arm ends, and a plurality of second arms configured to extend from the first sidewall stem to second arm ends, the second arm ends include first rotation limiters. The first sidewall stem is configured to be received into the first sidewall connector. The first arm ends include first lobe mechanisms. The first lobe mechanisms include first rounded outer lobe portions configured to rotatably engage the first saddle socket and releasably secure the cover plate to the first sidewall. The first rotation limiters include first catch portions configured to engage the first saddle socket and limit rotation of the first saddle socket relative to the first rotation limiters. The second sidewall connects between the base plate and the cover plate. The second sidewall includes a second sidewall stem, a plurality of third arms configured to extend from the second sidewall stem to third arm ends, and a plurality of fourth arms configured to extend from the second sidewall stem to fourth arm ends. The second sidewall stem is configured to be received into the second sidewall connector. The third arm ends include second lobe mechanisms. The second lobe mechanisms include second rounded outer lobe portions configured to rotatably engage the second saddle socket and releasably secure the cover plate to the second sidewall. The fourth arm ends include second rotation limiters. The second rotation limiters include second catch portions configured to engage the second saddle socket and limit rotation of the second saddle socket relative to the second rotation limiters. The first arms and the second arms are arranged in a pattern of alternating positions along a length of the first sidewall stem. The third arms and the fourth arms are arranged in a pattern of alternating positions along a length of the second sidewall stem. Example 14. The cable duct assembly of Example 13, wherein at least one of the first rounded outer lobe portions include a first radius, wherein the first arms include a rounded inner lobe portion, and wherein the rounded inner lobe portion includes a second radius. The first radius is greater than the second radius. At least one of the first and second lobe mechanisms further include a detent step defined intermediate the rounded outer lobe portion and the rounded inner lobe portion, the detent step configured to prevent over-rotation of the cover plate relative to the first arms beyond an angular limit. Example 15. The cable duct assembly of Example 13, wherein the first saddle socket includes a first saddle channel defined between a first flange and a second flange. Example 16. The cable duct assembly of Example 15, further including a guide ramp that extends from the second flange. The guide ramp is configured to align at least one of the first arms or second arms for insertion into the first saddle socket. Example 17. The cable duct assembly of Example 16, wherein the first flange includes a cover hook portion configured to extend to the first saddle channel. At least one of the first rounded outer lobe portions includes a first radius. The first arms include a rounded inner lobe portion that includes a second radius. The first radius is greater than the second radius. At least one of the first lobe mechanisms further include a detent step defined intermediate the rounded outer lobe portion and the rounded inner lobe portion. The detent step prevents over-rotation of the cover plate relative to the first arms beyond an angular limit. The second flange further includes a socket projection configured to engage the detent step. Example 18. The cable duct assembly of Example 17, wherein the first rotation limiters are generally C-shaped, having a front jaw and a rear jaw that define a recess therebetween. The front jaw is configured for receipt into the first saddle channel with the recess configured to receive the cover hook portion therein. The first rotation limiters are configured to engage the first saddle socket at the cover hook portion to limit rotation of the first saddle socket relative to the first rotation limiters. Example 19. A cable duct assembly that defines a passageway for retaining an elongated cable. The cable duct assembly includes a cover plate, a base plate, a first sidewall, and a second sidewall. The cover plate defines a first saddle socket spaced apart from and generally parallel to a second saddle socket. The first saddle socket includes a first flange and a second flange configured to define a first saddle channel therebetween. The second saddle socket includes a third flange and a fourth flange configured to define a second saddle channel therebetween. The first flange further includes a first cover hook portion configured to extend to the first saddle channel and the third flange further includes a second cover hook portion configured to extend to the second saddle channel. The base plate is arranged opposite the cover plate. The base plate defines a first sidewall connector and a second sidewall connector that is spaced apart from and generally parallel to the first sidewall connector. The first sidewall connects between the base plate and the cover plate. The first sidewall includes a first sidewall stem, a plurality of first arms configured to extend from the first sidewall stem to first arm ends, and a plurality of second arms configured to extend from the first sidewall stem to second arm ends. The first sidewall stem is configured to be received into the first sidewall connector. The first arm ends include first lobe mechanisms that include first rounded outer lobe portions configured to rotatably engage the first saddle socket and that releasably secure the cover plate to the first sidewall. The second arm ends include first rotation limiters that include first catch portions configured to engage the first saddle socket and limit rotation of the first saddle socket relative to the first rotation limiters. The second sidewall is configured to connect between the base plate and the cover plate. The second sidewall includes a second sidewall stem, a plurality of third arms configured to extend from the second sidewall stem to third arm ends, and a plurality of fourth aims configured to extend from the second sidewall stem to fourth arm ends. The second sidewall stem is configured to be received into the second sidewall connector. The third arm ends include second lobe mechanisms that include second rounded outer lobe portions configured to rotatably engage the second saddle socket and releasably secure the cover plate to the second sidewall. The fourth arm ends include second rotation limiters that include second catch portions configured to engage the second saddle socket and limit rotation of the second saddle socket relative to the second rotation limiters. Example 20. The cable duct assembly of Example 19, wherein at least one of the first and second rotation limiters is generally C-shaped and include a front jaw and a rear jaw that define a recess therebetween, the front jaw configured to be received into the respective saddle channel, the recess configured to receive the respective cover hook portion therein, the first rotation limiter configured to engage the first saddle channel at the first cover hook portion to limit rotation of the first saddle socket relative to the first rotation limiters, and the second rotation limiter configured to engage the second saddle channel at the second cover hook portion to limit rotation of the second saddle socket relative to the second rotation limiters. While cable duct assemblies have been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. Moreover, the use of the terms first, second, third, fourth, upper, lower, etc. does not denote any order of importance or orientation, but rather the terms first, second, third, fourth, upper, lower, etc. are used to distinguish one element from another. The use of “e.g.,” “etc.,” “for instance,” “in example,” “for example,” and “or” and grammatically related terms indicates non-exclusive alternatives without limitation, unless the context clearly dictates otherwise. The use of “including” and grammatically related terms means “including, but not limited to,” unless the context clearly dictates otherwise. The use of the articles “a,” “an” and “the” are meant to be interpreted as referring to the singular as well as the plural, unless the context clearly dictates otherwise. Thus, for example, reference to “a wall nodule” includes two or more such wall nodules, and the like. The use of “optionally,” “alternatively,” and grammatically related terms means that the subsequently described element, event or circumstance may or may not be present/occur, and that the description includes instances where said element, event or circumstance occurs and instances where it does not. Words of approximation (e.g., “substantially,” “generally”), as used in context of the specification and figures, are intended to take on their ordinary and customary meanings which denote approximation, unless the context clearly dictates otherwise. As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c). The description and the referenced drawings provide illustrative examples of that which the inventor(s) regard as their invention. As such, the embodiments discussed herein are merely exemplary in nature and are not intended to limit the scope of the invention, or its protection, in any manner Rather, the description and illustration of these embodiments serve to enable a person of ordinary skill in the relevant art to practice the techniques and apparatuses disclosed herein. While various embodiments of the disclosure are described in the foregoing description and are illustrated in the drawings, it is to be understood that this disclosure is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the disclosure as defined by the following claims. | 46,194 |
11862951 | DETAILED DESCRIPTION The embodiments or implementations disclosed in the above drawings and the following detailed description are not intended to be exhaustive or to limit the present disclosure to these embodiments or implementations. FIG.1shows a cable channel10for receiving a cable12, which is designed for example as an electric cable having one or more electrical lines. The cable channel10has a combination of a plurality of (e.g., identically designed) cable housings14, which receive the cable12along an axial cable longitudinal direction or channel longitudinal direction16, at least in sections—here along a section18. For combining and arranging a plurality of cable housings14together, a plurality of connectors and corresponding mating connectors are provided on the cable housings14. According to some embodiments, all the cable housings14are designed to be identical, at least functionally and in terms of their dimensions and geometrical measurements. The connectors and corresponding mating connectors are therefore present on each cable housing14. The connectors and corresponding mating connectors yet to be described are designed in such a way that a multiplicity of cable housings14can be arranged together in the channel longitudinal direction16and/or in a transverse direction20transversely to the channel longitudinal direction16(FIG.1,FIG.2). It can be seen from a comparison betweenFIG.1andFIG.3that the cable housing14has two mutually cooperating housing shells22,24. A first housing shell of the cable housing14acts as a receiving shell22for receiving the cable12. A second housing shell then acts as a cover shell24or a cover for effective mechanical protection of the cable12inserted into the receiving shell22. The cover shell24has a planar outer surface28on its cover outer side26. As a result, the entire cable channel10can have a substantially planar cover outer side26or outer surface, which facilitates its handling in terms of assembly, i.e., its installation in a vehicle. After the respective portion of the cable12has been inserted into the receiving shell22(FIG.1), the cover shell24is releasably connected to the receiving shell22in order to complete the cable housing14and to form a channel-like cavity23for the cable12(FIG.2). It can be seen inFIG.3that, for the connection of the two shells22,24, assembly lugs30of the cover shell24engage in assembly recesses32in the receiving shell22. These assembly elements30,32can be designed in such a way that they facilitate a releasable connection (e.g., a form- and/or force-fitting latching) of the two shells22,24. Four cable housings14arranged together are visible inFIG.1andFIG.2. In this case, two cable housings14are arranged together in the channel longitudinal direction16in each case, so that two parallel longitudinal rows34are formed. As seen in the transverse direction20, two cable housings14are likewise arranged together in each case, so that two transverse rows36are formed. However, for assembly reasons, the cable housings14of the transverse row36are arranged regularly offset in the channel longitudinal direction16. It can be seen inFIG.3that the receiving shell22has, on its one end portion38on the channel longitudinal side, a connector40which is releasably connected to a corresponding mating connector42of a further end portion44of the adjacent receiving shell22. The individual receiving shells22have in each case both the connector40and the corresponding mating connector42. Any number of cable housings14can thus be arranged together in the channel longitudinal direction16. If a further cable housing14or further receiving shell22is not added at the respective end portion38,44of the receiving shell22, a releasable connection of the connector40and/or the corresponding mating connector42to a terminating part46is provided. The terminating part46supports flanking means in the form of a plurality of flanking webs48and possibly additionally a flanking ring50. The flanking webs48are arranged at a spacing from one another in a circumferential direction52extending transversely to the channel longitudinal direction16and extend substantially in the channel longitudinal direction16. The flanking ring50extends in the circumferential direction52and is arranged partially inside and partially outside the flanking webs48, as seen radially. The above-mentioned flanking means48,50flank the cable12outside the cable housing14near to the end portion38or end portion44. Depending on the configuration, individual flanking means48,50flank the cable12with or without a radial spacing. They help to ensure that the portion18of the cable12which is received by one or more cable housings14remains in the desired specified position and substantial relative movements between the portion18of the cable12and the receiving cable housing(s) are therefore not generated axially or in the channel longitudinal direction16. To this end, the flanking ring50is designed for example as a cable tie, which is tightly fastened until the cable12is pressed radially against individual flanking webs48. The terminating parts46moreover help to ensure that the cable12, outside the received portions18, retains free portions54which create flexible bending portions for flexible installation of the entire cable channel10in the installation area, e.g., in a vehicle. It can be seen inFIG.4that the receiving shell22has, at its outer side56, a plurality of connectors in the form of flat connection arms58, which extend substantially in the transverse direction20. Each connection arm58incorporates a through-hole60and corresponds to a connection pin62, which is arranged as a corresponding mating connector on the outer side56of the further receiving shell22. The connection arm58and the corresponding connection pin62form a technically easily releasable connection of two cable housings14in the transverse direction20. A hole wall64of the through-hole60and the corresponding connection pin62abut against one another in the manner of a form-fitting connection, which is maintained as a result of a spring force F acting in the transverse direction20. The spring force F is generated by a plurality of spring blocks68arranged on an outer flank66of the receiving shell22. In the assembled state of the cable housings14arranged together in the transverse direction20, the spring force F of the spring blocks68acts in each case on a counter-block70. The counter-blocks70are arranged on a further outer flank72of the receiving shell22. If the two cable housings14arranged together in the transverse direction20are pressed against one another in the transverse direction20by a counter-force which is greater than the spring force F of the spring blocks68, the releasable connection58,62can be broken. As can be seen inFIG.3, the spring blocks68, and also the counter-blocks70, are enclosed in the receiving shell22with break-away walls74,76, which can be removed manually to form a cable outlet or a protected cable access point extending between adjacent cable housings14. Additionally, break-away portions78are provided in the cover shell24, which break-away portions can likewise be removed to enlarge the associated cable outlet or cable passage in the region of the associated spring block68or counter-block70. FIG.5shows the underside (already shown inFIG.4) of the cable channel10with the outer sides56of the receiving shells22. A line80is releasably secured on this underside. The line80can be designed as a busbar, for example a grounding busbar, and thus helps to ensure the mechanical stabilization of the cable channel10. For releasable securing of the line80, two securing rows82extending equidistantly in the channel longitudinal direction16are present on the cable housing14, more precisely in the region of the outer side56of the receiving shell22. Each securing row82has a plurality of securing elements84which are mutually spaced in the channel longitudinal direction16. They are designed for example in the manner of latching webs, which can be resiliently flexible in the transverse direction20. The terminology used herein is for the purpose of describing example embodiments or implementations and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the any use of the terms “has,” “includes,” “comprises,” or the like, in this specification, identifies the presence of stated features, integers, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the present disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components or various processing steps, which may include any number of hardware, software, and/or firmware components configured to perform the specified functions. Terms of degree, such as “generally,” “substantially,” or “approximately” are understood by those having ordinary skill in the art to refer to reasonable ranges outside of a given value or orientation, for example, general tolerances or positional relationships associated with manufacturing, assembly, and use of the described embodiments or implementations. As used herein, “e.g.,” is utilized to non-exhaustively list examples and carries the same meaning as alternative illustrative phrases such as “including,” “including, but not limited to,” and “including without limitation.” Unless otherwise limited or modified, lists with elements that are separated by conjunctive terms (e.g., “and”) and that are also preceded by the phrase “one or more of” or “at least one of” indicate configurations or arrangements that potentially include individual elements of the list, or any combination thereof. For example, “at least one of A, B, and C” or “one or more of A, B, and C” indicates the possibilities of only A, only B, only C, or any combination of two or more of A, B, and C (e.g., A and B; B and C; A and C; or A, B, and C). While the above describes example embodiments or implementations of the present disclosure, these descriptions should not be viewed in a restrictive or limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the appended claims. | 10,785 |
11862952 | DETAILED DESCRIPTION Although certain embodiments and examples are described below, those of skill in the art will appreciate that the disclosure extends beyond the specifically disclosed embodiments and/or uses and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the disclosure herein disclosed should not be limited by any particular embodiments described below. Watertight Electrical Compartment FIG.1shows an embodiment of a watertight electrical compartment10to be used in an irrigation device. The watertight electrical compartment10can comprise an electrical compartment body100, a sealing ring120, a sealing cap140, and/or a cap retainer160. The electrical compartment body100, the sealing cap140, and the cap retainer160can be made of any material suitable for environments exposed to water, mud, dirt, and the like, such as plastic materials. The compartment body100, the sealing cap120, and the cap retainer160can be made of the same material or different materials. The electrical compartment10can be of any size depending on a user's need. In some embodiments, the sealing ring120can be mounted on the sealing section114of the compartment body100. The sealing cap140can mate with the sealing section114and/or the sealing ring120to seal the compartment body100. The cap retainer160can connect to the compartment body100and retain the sealing cap140in a sealed position between the cap retainer160and the compartment body100. As shown inFIG.1, the electrical compartment body100can be cylindrically shaped with an first (e.g., open) end102and a second (e.g., closed) end106. The shape of the compartment body100is not limiting. For example, in some cases, the compartment body100has a polygonal cross-section, an elliptic cross-section, or some other shape. The compartment body100can further comprise a wall104between the open and closed ends102,106. The wall104can have different/varying thicknesses from the open end102to the closed end106. An inner wall surface110and the closed end106can define a chamber112. In the illustrated embodiment, the chamber112can be cylindrically shaped. In other embodiments, the chamber112can have other shapes, such as, for example, rectangular or conical. In the illustrated embodiment, the inner wall surface110and the closed end106can be smooth. In other embodiments, the inner wall surface110and the closed end106can have irregular surfaces. In some embodiments, the chamber112can house a battery. In those embodiments, the chamber312can have battery contacts (e.g., the batter contacts3120as shown inFIG.7). In some embodiments, the chamber312can also house electronic components or circuitry, for example, DIP switch3124(shown inFIG.7), flash programming pads3122(shown inFIG.7), memory cards, and the like. The type of electronic components or circuitry housed in the chamber112is not limiting. Electronic components or circuitry can be embedded at the bottom of the chamber112, in the inner wall surface110of the chamber112, and/or in some other location. The location of the electronic components in the chamber112is not limiting. Turning back toFIG.1, a sealing section114can be located on an outer wall surface108of the compartment body100near the open end102. The wall104can have a first outer diameter at the sealing section114. In some embodiments, the sealing section114can have one or more grooves116on the outer wall surface108, each groove116configured to receive one or more sealing rings. In some embodiments, the sealing section114can have a plurality of grooves116, each groove configured for receiving a sealing ring120. On the outer wall surface108, external threads118can be located further away from the open end102than the sealing section114. The external threads118can have a major diameter that is greater than the first outer diameter of the wall104at the sealing section114. In the illustrated embodiment, a different between the major diameter of the external threads118and the first outer diameter of the wall104is large enough to accommodate a wall thickness of the cap140. In some embodiments, the external threads can be custom threads having any desired size and/or tolerance. In the illustrated embodiment, the external threads118can be separate from the sealing section114so as not to interfere and/or overlap with the sealing section114. A portion of the compartment body100near the closed end106can have a third outer diameter that is substantially the same or greater than the major diameter of the external threads118. The third outer diameter can be substantially the same as an outer diameter of the cap retainer160to advantageously provide a smooth and esthetically pleasing outer shape of the sealed electrical compartment10. In some embodiments, portions of, or the entire third outer diameter are smaller than the major diameter of the external threads118and/or smaller than the outer diameter of the cap retainer160. With continued reference toFIG.1, the sealing ring120can have an inner diameter configured for being received by the sealing section114. In the illustrated embodiment, the sealing ring120can have an inner diameter configured for a tight fit between the sealing ring120and the groove116. The sealing ring120can also have an outer diameter that is greater than the first outer diameter of the wall104at the sealing section114. When the sealing ring120is received at the sealing section114, a portion of the sealing ring120can extend radially outward from the outer wall surface108at the sealing section114. The precise extent to which the sealing ring120extends out from the grooves116is not limiting. In some embodiments, the sealing ring120can be resilient. In some embodiments, the sealing ring120can be made from elastomeric materials. For example, the sealing ring120can be an O-ring. The resilient sealing ring120can advantageously conform to a space between the outer wall104of the compartment body100and an inner wall surface142(shown inFIG.2) of the sealing cap140when the sealing cap140slides over the sealing section114, thereby providing effective sealing of the electrical compartment10. In some embodiments, one sealing ring120can be used. In other embodiments, a plurality of sealing rings can be used. In some embodiments, grease can be applied on the sealing ring120to allow the sealing cap140to slide smoothly over the sealing ring120mounted on the sealing section114and/or to reduce wear on the sealing ring120. As shown inFIG.1, the sealing cap140can be cylindrically shaped, although the shape of the sealing cap140is not limiting. The sealing cap140can have a first (e.g., open) end144, a second (e.g., closed) end146, and a wall148between the open and closed ends144,146. More details of the sealing cap140will now be described with respect toFIG.2.FIG.2shows a cross-sectional view of a watertight electrical compartment20. The electrical compartment20is similar to the electrical compartment10except that that the electrical compartment20can have two sealing rings120. Accordingly, features of the electrical compartment20can be incorporated into features of the electrical compartment10and features of the electrical compartment10can be incorporated into features of the electrical compartment20. As shown inFIG.2, an inner wall surface142of the cap140can have an internal diameter configured to have a sliding fit with the sealing section114and an interference fit with the sealing ring120when the sealing ring120is mounted on the sealing section114. Also as shown inFIG.2, the sealing ring120can be compressed between the groove116and the inner wall surface142of the sealing cap140. In the illustrated embodiments, the inner wall surface142is not threaded. Turning back toFIG.1, the wall148of the sealing cap140has a greater outer diameter near its open end144than at its closed end146. As mentioned above, the thickness of the wall148can be defined by the difference between the greater outer diameter and the internal diameter and can be smaller than the difference between the major diameter of the external threads118and the first outer diameter of the wall104of the compartment body100. With reference toFIGS.1-2, when the sealing cap140fits over the sealing section114of the compartment body100, an outer wall surface149of the sealing cap140can be located radially inward from the major diameter of the external threads118, thereby advantageously inhibiting or preventing the sealing cap140from blocking the cap retainer160from moving at least partially past the sealing cap140toward the second end106of the compartment body100. The outer wall surface149also has a reduced-diameter portion150extending from the closed end146toward the open end144. In some embodiments, the reduced-diameter portion150can have a height of about 0.1″ to 0.5″. In some embodiments, the reduced-diameter portion150can have a height of about 0.15″. In the illustrated embodiments, the reduced-diameter portion150can be cylindrical with a substantially uniform diameter. In other embodiments, the reduced-diameter portion150can be tapered, with the diameter increasing, e.g. gradually, from the closed end146toward the open end144. In some embodiments, the sealing cap140can have one or more notches152at the open end144. The notches152can advantageously allow the cap140be pried open, e.g. with a screw driver or other tool, in case the cap140is stuck during removal of the cap140from the compartment body100to reopen the sealed compartment10. With continued reference toFIG.1, the cap retainer160can be cylindrically shaped, although the shape of the cap retainer160is not limiting. The cap retainer160can have a first end162, a second end164, and a wall166between the first and second ends162,164. An inner wall surface168of the cap retainer160can have internal threads170configured to threadedly mate with the external threads118of the compartment body100. In some embodiments, the internal threads170can be located near the first end162(e.g., nearer the first end162than the second end164). Having the internal threads170on the cap retainer160instead of on the sealing cap140can advantageously allow easy turning of the cap retainer160because the sealing cap140can cover the sealing ring120from the cap retainer160. For example, the threaded engagement between the cap retainer160and component body100can be separate from the sealed engagement between the cap140and the body100. The internal threads170can be custom threads having any desired size and/or tolerance. The inner wall surface168can have an internal diameter that is bigger than the greater outer diameter of the sealing cap140. In some embodiments, the cap retainer160and the sealing cap140can have a sliding fit. The sliding fit can allow the cap retainer160and the sealing cap140to rotate and/or move easily against each other. In some embodiments, the cap retainer160and the sealing cap140can have a running fit. The running fit can allow the cap retainer160and the sealing cap140to rotate and/or move freely past each other. In the illustrated embodiment, the inner wall surface168can also have a non-threaded portion further away from the first end162of the cap retainer160than the internal threads170. The non-threaded portion can advantageously allow the cap retainer160to smoothly move over at least a portion of the sealing cap140. In the illustrated embodiment, the second end164of the cap retainer160can have an opening172surrounded by a shoulder174. The opening172can have a diameter that is greater than the reduced diameter of the reduced-diameter portion150of the sealing cap140, but less than the greater diameter of the sealing cap140. As shown inFIG.2, when the cap retainer160is advanced from the closed end146of the sealing cap to its open end144, the reduced-diameter portion150of the sealing cap140can pass through the opening172, when the rest of the sealing cap140can be stopped from exiting the opening172by the shoulder174. A depth of the opening172can be defined by a thickness of the cap retainer160at the second end164. In some embodiments, the depth of the opening172can be about 0.1″ to 0.5″. In the illustrated embodiment, the depth of the opening172is the substantially same as the height of the reduced-diameter portion150of the sealing cap140so that the closed end146of the sealing cap140can be substantially flush with the second end164of the cap retainer160, resulting in a smooth and esthetically pleasing shape of the electrical compartment10when the electrical compartment10is sealed. Also as shown inFIG.2, the opening172through the second end164has a substantially uniform diameter. In other embodiments, the opening172can be tapered, with the diameter increasing (e.g. gradually increasing) from the second end164toward the first end162. In yet other embodiments, the opening172can have one or more raised bumps or grooves to snap onto one or more corresponding grooves or raised bumps on the reduced-diameter portion150of the sealing cap140. In some embodiments, the second end164can be closed to retain the sealing cap140. The embodiment of watertight electrical compartments10,20, as shown inFIGS.1-2can advantageously provide effective sealing via the sealing ring120between the compartment body100and the sealing cap140, while still allowing easy turning of the cap retainer160, which is separate from the sealing cap140and not subject to the friction provided by the sealing ring120. The cap retainer160can retain the sealing cap140in a sealed position by the mating of the internal threads170on the cap retainer160and the external threads118on the compartment body100. The cap retainer160can also be easily screwed on and off from the compartment body100to allow replacement and/or servicing of the electrical components housed inside the chamber112. Turning back toFIG.1, the outer wall surface108near the closed end106of the compartment body100, the outer wall surface149near the closed end146of the sealing cap140, and/or an outer wall surface167near the second end164of the cap retainer160can further have a rugged or textured surface to increase friction between the outer wall surface and a user's hand for easy gripping. In other embodiments, the entire outer wall surfaces108,149,167can be rugged or textured. In the illustrated embodiment, the outer wall surfaces108,149,167can have a plurality of vertical indentations extending down a portion of the outer wall surfaces108,149,167. In other embodiments, the outer wall surfaces108,149,167can be corrugated. In yet other embodiments, the outer wall surfaces108,149,167can have raised pumps. In some embodiments, a modified watertight electrical compartment can be similar to the electrical compartment10and can have features of the electrical compartment10except as described below. The modified electrical compartment can have a compartment body with a smooth outer wall surface near its open end102and a sealing cap140with a sealing section on its inner wall for receiving at least one sealing ring. In some embodiments, such as shown inFIGS.2A and2B, a modified watertight electrical compartment22can be similar to the electrical compartment10,20ofFIGS.1and2and can have features of the compartment10,20except as described below. As shown inFIG.2B, instead of having internal threads170like the cap retainer160ofFIGS.1and2, the cap retainer260can have external threads270at or near the second end262. Instead of having external threads118like the compartment body100ofFIGS.1and2, the compartment body200inFIGS.2A and2Bcan have a channel219(e.g., an annular channel) with internal threads218located on a radially inwardly facing inner wall of the channel219. The channel219can be substantially concentric with the wall204between the first (e.g., open) end202and the second (e.g., closed) end206. The channel219can begin near the sealing section214further away from the first end202and extend toward the second end206along a length of the compartment body200. The channel219can have a width configured to accommodate the threaded portion of the cap retainer260that includes the external threads270. The sealing cap140can mate with the sealing section214and/or the sealing ring120to seal the compartment body100. The external threads270of the cap retainer260can mate with the internal threads218of the compartment body200to retain the sealing cap140in a sealed position between the cap retainer260and the compartment body200. In some embodiments, such as shown inFIG.2C, another modified watertight electrical compartment24can be similar to the electrical compartment22ofFIGS.2A and2Band can have features of the compartment22except as described below. As shown inFIG.2C, the sealing section214of the compartment body200can have a smooth surface. The inner wall242of the sealing cap240can include one or more grooves216. Each groove216can be configured to receive one or more resilient sealing rings120. The resilient sealing ring120can advantageously conform to a space between the sealing section214of the compartment body200and an inner wall surface242of the sealing cap240when the sealing cap240slides over the sealing section214of the compartment body200, thereby providing sealing of the electrical compartment24. Having the external threads on the retainer cap and the internal threads on the compartment body can create a tortuous path for water, dirt, and/or others to enter the chamber212. The tortuous path can reduce and/or eliminate the amount of water, dirt, and/or others that can reach and/or accumulate at or near the interface between the sealing cap and the sealing section of the compartment body. In some embodiments, such as shown inFIG.2D, a modified watertight electrical compartment26can be similar to the electrical compartment10,20ofFIGS.1and2and can have features of the compartment10,20except as described below. As shown inFIG.2D, the sealing section214of the compartment body200can have a smooth surface. The inner wall242of the sealing cap240can include one or more grooves216. Each groove216can be configured to receive one or more resilient sealing rings120. The resilient sealing ring120can advantageously seal a space between the sealing section114of the compartment body100and an inner wall surface242of the sealing cap240when the sealing cap240slides over the sealing section114of the compartment body100, thereby providing sealing of the electrical compartment26. Methods of Sealing a Watertight Electrical Compartment Methods of sealing a watertight electrical compartment, such as the electrical compartments10,20,22,24,26ofFIGS.1,2, and2A-2Dwill now be described. The electrical compartment body100,200as described above can be provided for housing electronic components and/or circuitry in its chamber. A sealing ring120can be fitted into the groove116,216, which can be located on the sealing section114or the inner wall242of the sealing cap240. As shown inFIGS.2and2B-2D, a plurality (e.g., two or more) of sealing rings120can be used in sealing the compartment. In some embodiments, the sealing ring120can be resilient, for example, an O-ring. In some embodiments, such as shown inFIGS.2and2B, the sealing ring120can be slightly expanded by a radially outward force to clear the first outer diameter of the compartment body100,200and then advanced from the open end102,202of the compartment body100,200to the sealing section114,214. The radially outward force on the sealing ring120can then be released so that the sealing ring120can form a tight fit with the sealing section114,214. In some embodiments, the sealing ring120can form a tight fit with the groove116of the sealing section114,214. In some embodiments, a plurality of the sealing rings can be mounted in one groove (not shown). In some embodiments, there may be more than one groove116with one sealing ring120in each groove116. With continued reference toFIGS.1,2, and2A-2D, the sealing cap140,240as described above can be placed over the sealing section114,214. The sealing section114,214can be directed through the open end144of the sealing cap140,240to reach a sealed position. The inner wall surface142,242of the sealing cap140,240can slide over the outer wall surface108,208of the sealing section114. In some embodiments, such as shown inFIGS.2and2B, the inner wall surface142of the sealing cap140can compress an outer diameter of the sealing ring120mounted on the sealing section114,214as the sealing cap140moves over the sealing section114,214. The compressed sealing ring120can advantageously seal any space between the inner wall surface142of the sealing cap140and the outer wall surface108of the sealing section114, thereby sealing the space. In some embodiments, such as shown inFIGS.2C and2D, the sealing ring(s) can be positioned on the inner wall surface142(e.g., in grooves) prior to mating the cap140with the sealing section114. Placing the sealing cap240over the sealing section114,214of the compartment body100,200can cause the sealing section114,214to expand an inner diameter of the sealing ring120fitted in the groove216on the sealing cap240. The sealing ring120can seal any space between the inner wall surface242of the sealing cap240and the outer wall surface of the sealing section114,214. With the sealing cap140,240in the sealed position, the cap retainer160,260as described above can be advanced over the sealing cap140,240. For example, the sealing cap140,240can pass through the first end162,262of the cap retainer160,260. The wall thickness of the sealing cap140,240can allow the outer wall surface149,249of the sealing cap140,240to be located radially inward of the outer wall surface108at the major diameter of the external threads118inFIGS.1-2and2D, or radially inward of the channel262inFIGS.2B and2C. The cap retainer160,260can thus be advanced over at least a portion of the sealing cap140,240unhindered. In some embodiments, such as shown inFIGS.1-2and2D, the cap retainer160can be advanced over at least a portion of the sealing cap140,240unhindered until the internal threads170of the cap retainer160reach the external threads118of the compartment body100. In some embodiments, such as shown inFIGS.2B-2C, the cap retainer260can be advanced over at least a portion of the sealing cap140,240unhindered until the external threads270of the cap retainer260reach the internal threads218of the compartment body200. The cap retainer160,260can be turned so that the threads of the cap retainer and the compartment body can mate with each other to lock the cap retainer160,260on the compartment body100,200. The cap retainer160can also have a stopper on the second end164for preventing the sealing cap140from disengaging the sealing section114and/or the sealing ring120, thereby locking the sealing cap140in the sealed position. As shown inFIGS.1-2and2D, the stopper can comprise the shoulder174as described above so that only the reduced-diameter portion150of the sealing cap140can pass through the opening172and the rest of the sealing cap140can be stopped from moving through the opening172by the shoulder174because the opening172can be smaller than the greater outer diameter of the sealing cap140. However, one of ordinary skill in the art should appreciate from the disclosure herein that other types of stopper can be used to keep the sealing cap140in the sealed position. In some embodiments, the shoulder174contacts the major-diameter portion of the sealing cap140before all the internal threads170can engage the external threads118. In other embodiments, the shoulder174can just contact the major-diameter portion of the sealing cap140as all the internal threads170have substantially engaged the external threads118. As shown inFIGS.2B-2C, the cap retainer260can have similar stopper features. Wireless Flow Sensor Assembly (WFS) Example applications for a watertight electrical compartment, such as the electrical compartments10,20,22,24,26as shown inFIGS.1,2, and2A-2D, will now be described. In some embodiments, the electrical compartment30can be used in a wireless flow sensor assembly (WFS) inFIGS.3-5. The electrical compartment30is similar to the electrical compartments10,20,22,24,26ofFIGS.1,2, and2A-2Dexcept as described below. Accordingly, features of the electrical compartment30can be incorporated into features of the electrical compartments10,20,22,24,26and features of the electrical compartments10,20,22,24,26can be incorporated into features of the electrical compartment30. As shown inFIGS.3and4A-4F, the WFS assembly3can include the watertight electrical compartment30, an antenna dome330, a lid retainer nut35, a flow sensor retainer cap36, a flow sensor32, and/or an electrical wire34connecting the flow sensor32and the electrical compartment30. In some embodiments, two or more components in the assembly communicate via wireless connection. The sealing cap340, sealing retainer360, and sealing section314(shown inFIG.5) of the compartment body300can operate in the same or in a similar manner to the operation of the sealing cap140, sealing retainer160, and sealing section114of the compartment body100described above. As shown inFIG.3, the flow sensor32can have an impeller3200on a first end3202. The flow sensor32can also be electrically coupled to the wire34at a second end3204. The flow sensor32can be installed on a water line (e.g., into a T-connector perpendicular to a main water pipe that supplies water to an irrigation device). The flow sensor retainer36can retain the sensor32onto the T-connector. In the illustrated embodiment, the wire34can pass through a hole3600of the flow sensor retainer36. The impeller3200can turn as the water flows through the pipe. The flow sensor32can generate a signal at intervals or continuously based on the amount of flow. For example, the flow sensor32can generate a signal each time a predetermined volume of water has flowed past the sensor32. The signal can be sent in a manner described below to an irrigation controller (not shown) that can interpret and respond to the signal data from the sensor32. As described above, the wire34can electrically couple the flow sensor32and the electrical compartment30.FIG.5illustrates an exploded view of the electrical compartment30. As shown inFIG.5, a chamber312of the compartment body300can house a battery holder38or39. In some embodiments, the battery holder38may house a “D” size battery. In some embodiment's, the battery holder39may hold one or more “AA” sized batteries. In some embodiments, the battery holder39may hold three “AA” size batteries. Other battery holders holding different sized batteries could be used. In some embodiments, the chamber312holds a battery without a separate holder. In the illustrated embodiment, the battery holders38,39can have a shape complementary to a shape of the chamber312to advantageously minimize movements of the battery holders38,39inside the chamber312. The battery holders38,39can also have two protruding longitudinal ridges380,390that are not uniformly spaced around a circumference of the battery holders38,39. The chamber312can have two longitudinal notches3126located on the inner wall surface310and having substantially the same spacing as the ridges380,390. The ridge-notch configuration can guide a user to insert the substantially cylindrical battery holders38,39into the chamber312only in one orientation. As shown inFIG.5, the battery holders38,39can have flat protrusions384,394for easier holding of the battery holders38or39when assembling the WFS assembly3. In some embodiments, the ridge-notch configurations of the holders38,39and chamber312permit installation of the holders38,39in a plurality of rotational orientations with respect to the chamber312. In some embodiments, the chamber312may only have one notch3126. In some embodiments, battery holders38,39may only have one ridge380,390. Once the battery in the battery holder38-or39is positioned in the chamber312, the electrical compartment30can be sealed using the cap340and retainer360in a manner described above with respect to cap140and retainer160. As shown inFIGS.6A and6B, the inner wall surface342of the sealing cap340can compress the sealing ring320, e.g. two O-rings, against the sealing section314, such as the grooves316, of the compartment body300. The cap retainer360can be advanced over at least a portion of the sealing cap340. The shoulder374of the cap retainer360can inhibit the sealing cap340from moving through the opening372of the cap retainer360and disengaging the sealing section314and/or the sealing ring320when the cap retainer360is mated with the compartment body300. The internal threads370of the cap retainer360can mate with the external threads318of the compartment body300to lock the sealing cap340in its sealed position. Turning toFIG.7, the chamber312can have battery contacts3120at its closed end. As described above, in some embodiments, the battery can be loaded into the chamber312in only one orientation. The particular orientation of the battery can advantageously allow terminals of the battery to be in contact with the battery contacts3120when loaded into the chamber312. The chamber312can also have a DIP switch3124and flash programming pads3122. The battery, the DIP switch3124, and the flash programming pads3122can be electrically connected, e.g. in an electrical circuit, with the battery providing power to the circuit. As shown inFIG.5, the wire34can exit the compartment body300at a location between the open and closed ends302,306. The wire34can be electrically coupled to the battery contacts3120so that the battery can advantageously provide power to the flow sensor32. The wire can also send the signals from the flow sensor32to the electrical circuit inside the chamber312. The signals can then be transmitted wirelessly to an irrigation controller (not shown), thereby eliminating a possible need to physically wire the flow sensor32to the irrigation controller. The WFS assembly3can also have an antenna330to facilitate transmitting and/or receiving signals. In the illustrated embodiment, the antenna330can be dome-shaped and be attached to the closed end306of the compartment body300. In some embodiments, the antenna dome330can also receive signals, e.g. from the controller, a remote control, and/or a computer. In some embodiments, the antenna dome330can both transmit and receive signals. The antenna dome330can communicated wirelessly with another electronic device, such as the controller, intermittently or continuously. Turning back toFIG.3, the lid retainer nut35can be used to mount the electrical compartment30and the antenna dome330on a plastic lid of a valve box (not shown), in which the flow sensor32can be installed. Specifically, the outer wall surface308of the compartment body300can have external threads309. As shown inFIG.3, the external threads309can be located between the external threads318and the antenna dome330. The lid retainer nut35can have internal threads (not shown) that can threadedly mate with the external threads309of the compartment body300. In some embodiments, the external threads309can be custom threads having any desired size and/or tolerance. For installation, the sealed electrical compartment30can be passed through a hole on the lid (not shown). The antenna dome330can be located on an outer surface of the lid and can have a diameter that is bigger than the hole on the lid so that an undersurface332(shown inFIG.5) of the dome330can rest on the outer surface of the lid. The lid retainer nut35can be advanced from the sealed open end302of the compartment body300toward the dome330, while the internal threads of the lid retainer nut35can engage the external threads309. The lid retainer nut35can stop advancing toward the dome330when the lid retainer nut35contacts an inner surface of the lid. In some embodiments, the lid retainer nut35can be turned another quarter to a half turn after the lid retainer nut35touches the inner surface of the lid to advantageously fix the lid between the dome330and the lid retainer nut35. To reopen the installed electrical compartment30, the lid can be lifted open and turned over to exposed the sealed open end302. The cap retainer360can be unscrewed from the compartment body300. The cap retainer360can be easily unscrewed, not needing to overcome the friction of the sealing ring320. The sealing cap340can then be pulled away from the compartment body300. A tool such as a screwdriver can be used to pry open the sealing cap340at the notches352(shown inFIG.5) if the sealing cap340gets stuck with the sealing ring320. Once the electrical compartment30is reopened, the batteries can be replaced and/or electronic circuitry can be serviced. Battery-Operated Controller In some embodiments, the watertight electrical compartment can be incorporated into an irrigation controller to make a battery-operated controller80shown inFIGS.8A-Dand9. The battery operated controller80is similar to the electrical compartments10,20,22,24,26ofFIGS.1,2, and2A-2Dexcept as described below. Accordingly, features of the battery operated controller80can be incorporated into features of the electrical compartments10,20,22,24,26and features of the electrical compartments10,20,22,24,26can be incorporated into features of the battery operated controller80. As shown inFIG.9, the battery operated controller80can include a compartment body800having a chamber812, a sealing section814, and/or external threads818. The chamber812can accommodate batteries892(e.g., DC batteries). In the illustrated embodiment, the chamber812can have a shape that is complementary to a shape of the batteries892to minimize movement of the batteries892inside the chamber. In some embodiments, the battery operated controller80includes one or more battery holders configured to retain the batteries and electrically interface with one or more features of the battery operated controller80. Although not shown, the chamber812can also include electrical circuitry for connecting with the batteries892so that the electrical circuitry can draw power from the batteries892. The battery operated controller80also can have at least one (e.g., one, two, three, or more) sealing ring(s)820to be mounted on the sealing section814, and a sealing cap840having an inner wall surface (not shown) to engage the sealing section814and/or the sealing ring(s)820to provide sealing of the battery operated controller80. The battery operated controller80can further have a cap retainer860to retain the sealing cap840in a sealed position and having internal threads870to engage the external threads818of the compartment body800. The sealing cap840, sealing retainer860, and sealing portions of the compartment body800can operate in the same or in a similar manner to the operation of the sealing cap140, sealing retainer160, and compartment body100described above. Turning toFIGS.8A-B, the closed end810of the compartment body800can further have a user interface, including but not limited to control buttons895and/or a display896. Although not shown, the user interface of the compartment body800can be in an electrical connection with the circuitry and the batteries892in the chamber812. In some configurations, the battery operated controller80can allow irrigation to occur without tapping into an AC power. The battery operated controller80can be installed in places where it is difficult to connect the battery operated controller80to other sources of power (e.g., power lines). The sealing features of the battery operated controller80can allow the battery operated controller80to be installed in environments exposed frequently to rain, flooding, and/or mud without affecting the electrical circuitry and the batteries892sealed inside the chamber812. Wireless Battery-Operated Central Controller Assembly (BOCC) In some embodiments, the electrical compartment101can be used in a wireless battery-operated central controller assembly (BOCC)11inFIGS.10-12. The electrical compartment101is similar to the electrical compartments10,20,22,24,26ofFIGS.1,2, and2A-2Dexcept as described below. Accordingly, features of the electrical compartment101can be incorporated into features of the electrical compartments10,20,22,24,26and features of the electrical compartments10,20,22,24,26can be incorporated into features of the electrical compartment101. As shown inFIGS.10-12, the BOCC11can include the watertight electrical compartment101, a transmitter housing1085for housing transmitters1086(shown inFIG.13) and coupled to an antenna dome1030, a lid retainer nut1035, a flow sensor retainer cap1036, a flow sensor1032, and/or an electrical wire1034connecting the flow sensor1032and the electrical compartment101in a manner described below. In addition, as described above, the BOCC11is a battery powered irrigation controller that can be used to control multiple irrigation valves to turn those irrigation valves on and off. The BOCC11is in wireless communication with a central computer. Irrigation programs and other commands for turning on and off the irrigation valves can be initiated from the central computer. In some embodiments, at least one irrigation program may be sent from the central computer to the BOCC11and the BOCC11may store that irrigation program for future use. In some embodiments, the BOCC11may turn individual valves on and off in accordance with the stored irrigation programs. In some embodiments, the BOCC11can consume more power than the battery operated controller80. In addition, the battery that can be sealed within the electrical compartment101can be quickly depleted and may require frequent replacements. Further, the electrical compartment101can already be filled with electronic components and/or circuitry possibly needed for communicating wirelessly with the central computer and have no spare space for batteries. The BOCC11can thus have a separate battery pack1038to be electrically connected to the electrical compartment101via an electrical wire1080in a manner described below to meet the power consumption need of the BOCC11. As shown inFIG.12, the battery pack1038can have a container for holding a battery retainer1039. The batter pack1038and battery retainer1039can be constructed from a polymer, a ceramic, a metal, a combination thereof, and/or any other suitable material. The battery retainer1039can be sized, shaped, and configured to retain batteries having one or more different sizes and/or ratings. In the illustrated embodiment, the container and the battery retainer1039can have complementary shapes to minimize movement of the battery retainer1039inside the container. For example, the container can have tracks on its inner wall surface for guiding ridges on an outer surface of the battery retainer1039. The battery pack1038can also have a sealing cover1033to provide watertight sealing (e.g., with O-rings) of the container. A battery end1087of the wire1080can run through an opening1031of the sealing cover1033to contact the battery retainer1039. A sealing cap end1081of wire1080can also run through an opening1082(shown inFIG.14) of the sealing cap1040of the electrical compartment101to contact the electronic components and/or circuitry in the electrical compartment101. As shown inFIG.12, the battery pack1038can also have a mounting ring1037that can be used to hang the battery pack1138around the transmitter housing1085. The mounting ring1037can advantageously keep the battery pack1038within close proximity of the electrical compartment101, thereby reducing the danger of the battery pack1038moving further away from the electrical compartment101and tugging on the wire1080. Connection of the wire1080to the sealing cover1033and the sealing cap1040will now be described.FIGS.13-14illustrates how the sealing cap end1081of wire1080can be connected to the sealing cap1040. One of ordinary skill in the art would appreciate from the disclosure herein that the wire1080can be connected to the sealing cover1033in same or in a similar manner to the connection of the wire1080and the sealing cap1040as described below. As shown inFIGS.13-14, the sealing cap1040can comprise the opening1082for the electrical wire1080to pass through. As shown inFIG.13, the wire1080can have a seal (e.g., an overmolded strain relief1084) covering a portion of the wire1080at a sealing cap end1081of the wire1080. The portion of the wire1080covered by the overmolded strain relief1084can be passed through the opening1082on the closed end1046of the sealing cap1040. As shown inFIGS.13and14, the sealing cap1040can have a filling well1092facing an open end1044of the sealing cap1040. After the portion of the wire1080covered by the overmolded strain relief1084is passed through the opening1082, the filling well1092can be filled with a sealing material to seal any gap between the opening1082and the overmolded strain relief1084so as to prevent water or mud ingress into the cap1040and to fix the wire1080to the sealing cap1040. In some embodiments, the sealing material can be a polyurethane encapsulating compound. The strain relief1084can advantageously provide a transition from the flexible wire1080to a rigid connection point at the opening1082of the sealing cap1040. More particularly, the strain relief1084can prevent any mechanical force applied to an exterior of the wire1080from being transferred to the rigid connection point at the opening1082of the sealing cap1040, thereby reducing failure of the wire1080. In the illustrated embodiment, the electrical wire1080can terminate at an electrical connector1090after the wire1080is passed through the cap1040. The electrical connector1090can be connected to electrical components or circuitry housed in the chamber. In some embodiments, the wire1080can advantageously deliver power to electrical components or circuitry in the chamber. Returning to the electrical compartment as shown inFIG.12, besides the sealing cap1040, the electrical compartment101can have a compartment body1000, at least one (e.g., one, two, three, or more) sealing ring(s)1020, and a cap retainer1060. The electrical component101can be sealed in a manner described above in connection with the electrical compartments10,20,22,24,26. For example, the sealing cap1040, sealing retainer1060, and sealing portions of the compartment body1000can operate in the same or in a similar manner to the operation of the sealing cap140, sealing retainer160, and compartment body100described above. The electrical compartment101can further have connecting terminals1077exiting from the compartment body1000. The connecting terminals1077can connect to at least one irrigation valve. In some embodiments, there may be more connecting terminals1077to individually connect to more irrigation valves, (e.g., two, three, four, or more irrigation valves). In some embodiments, the BOCC11may be able to control each irrigation valve individually via programming or other commands sent from the central computer. In some embodiments, the electrical compartment101can have connecting terminals1079exiting from the compartment body1000. In some embodiments, the connecting terminals1079may be supplied as a loop, or otherwise connected together, to allow the controller to operate without an optional sensor. In other embodiments, the connecting terminals1079may be separated and connected to an optional sensor, such as a rain shut off sensor, a temperature sensor, or other sensors that may be used to inhibit and/or allow irrigation. For example, a user may cut a looped terminal1079and connect the open loop to a sensor (e.g., a rain shut off sensor). The rain sensor can be configured to close the loop in the absence of rain and open the loop in the presence of rain. Opening the loop can inhibit or prevent operation of the one or more irrigation valves. This functionality can reduce the likelihood that irrigation takes place during rain. The electrical compartment101can further have connecting terminals embedded into the wire1034exiting from the compartment body1000. The wire1034can connect to a flow sensor1032. The flow sensor1032can have similar functions as the flow sensor32shown inFIGS.4A-4Cand be mounted on a main water pipe as described above. The connecting terminals1077can also connect to other parts of the irrigation devices and/or to a central computer. With continued reference toFIG.12, a first end of the transmitter housing1085can be position on a closed end1006of the compartment body1000. In some embodiments, the transmitter housing1085can form an integral part with the compartment body1000. In other embodiments, the transmitter housing1085can be mechanically coupled (e.g., welded, adhered, fastened, and/or otherwise coupled) to the compartment body1000. As shown inFIG.13, the electrical connector1090can connect the wire1080to a controller circuitry1095inside the water electrical compartment101, which can advantageously protect the controller circuitry1095from water, mud, dirt, and the like. In the illustrated embodiment, the controller circuitry1095can be attached to an inner wall of the closed end1006of compartment body1000defining a ceiling of the chamber1012. The controller circuitry1095can also be electrically coupled to the transmitters1086. The transmitters1086can advantageously send ON/OFF and/or other control signals to irrigation devices. In some embodiments, the housing1085can house receivers (not shown). In some embodiments, the housing1085can house both the transmitters and receivers, or transceivers to advantageously communicate wirelessly with irrigation devices. The BOCC11can have a detachable dome1030to facilitate mounting the BOCC11to a lid of an irrigation box. The detachable dome1030can be mechanically attached to a second end of the transmitter housing1085. In some embodiments, the detachable dome1030can incorporate internal threads that can threadedly mate with external threads1088on an outer wall surface of the transmitting housing1085. The lid retainer nut1035can be used to mount the electrical compartment101, the transmitters1086in the transmitter housing1085, and the detachable dome1030on a plastic lid of a valve box (not shown). As shown inFIG.13, the lid retainer nut1035can have internal threads1089that can threadedly mate with the external threads1088of the transmitter housing1085. In some embodiments, the external threads1088can be custom threads having any desired size and/or tolerance. Installation of the BOCC11may be accomplished by removing the detachable dome1030and inserting the transmitter housing1085through a hole in the lid of a valve box. The detachable dome1030may then be reinstalled and tightened until hand tight. Tightening of the retainer nut1035may be performed to complete the installation, and reopening of the electrical compartment101can be in similar manners as described above regarding the WFS assembly3. Although this disclosure has been described in the context of certain embodiments and examples, it will be understood by those skilled in the art that the disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. In addition, while several variations of the embodiments of the disclosure have been shown and described in detail, other modifications, which are within the scope of this disclosure, will be readily apparent to those of skill in the art. Sensors other than flow sensors may be incorporated into any of the above mentioned devices. Other sensors may include soil moisture sensors, temperature, solar radiation, light, humidity, wind, and/or any other sensors that monitor irrigation efficiency, weather, plant conditions, or soil conditions. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the disclosure. For example, features described above in connection with one embodiment can be used with a different embodiment described herein and the combination still fall within the scope of the disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosure. Thus, it is intended that the scope of the disclosure herein should not be limited by the particular embodiments described above. Accordingly, unless otherwise stated, or unless clearly incompatible, each embodiment of this invention may comprise, additional to its essential features described herein, one or more features as described herein from each other embodiment of the invention disclosed herein. Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination. Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or steps are included or are to be performed in any particular embodiment. Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. Additionally, as used herein, “gradually” has its ordinary meaning (e.g., differs from a non-continuous, such as a step-like, change). The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. | 54,256 |
11862953 | Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of implementations. DETAILED DESCRIPTION This disclosure, its aspects and implementations, are not limited to the specific material types, components, methods, or other examples disclosed herein. Many additional material types, components, methods, and procedures known in the art are contemplated for use with particular implementations from this disclosure. Accordingly, for example, although particular implementations are disclosed, such implementations and implementing components may comprise any components, models, types, materials, versions, quantities, and/or the like as is known in the art for such systems and implementing components, consistent with the intended operation. The word “exemplary,” “example,” or various forms thereof are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” or as an “example” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Furthermore, examples are provided solely for purposes of clarity and understanding and are not meant to limit or restrict the disclosed subject matter or relevant portions of this disclosure in any manner. It is to be appreciated that a myriad of additional or alternate examples of varying scope could have been presented, but have been omitted for purposes of brevity. While this disclosure includes a number of implementations that are described in many different forms, there is shown in the drawings and will herein be described in detail particular implementations with the understanding that the present disclosure is to be considered as an exemplification of the principles of the disclosed methods and systems, and is not intended to limit the broad aspect of the disclosed concepts to the implementations illustrated. In the following description, reference is made to the accompanying drawings which form a part hereof, and which show by way of illustration possible implementations. It is to be understood that other implementations may be utilized, and structural, as well as procedural, changes may be made without departing from the scope of this document. As a matter of convenience, various components will be described using exemplary materials, sizes, shapes, dimensions, and the like. However, this document is not limited to the stated examples and other configurations are possible and within the teachings of the present disclosure. As will become apparent, changes may be made in the function and/or arrangement of any of the elements described in the disclosed exemplary implementations without departing from the spirit and scope of this disclosure. The present disclosure concerns a gasket100comprising an integrated bug cover102. The gasket100may be installed in an electrical outlet cover104and is configured to place the bug cover102in a position to limit the entrance of bugs and other contaminants into the electrical outlet cover104. As shown inFIGS.1-2, in addition to the bug cover102, the gasket100comprises a front face106, a rear face108opposite the front face106, and a central aperture110extending through the gasket100. The central aperture110may form the gasket100into a continuous ring around the central aperture110. The front face106and the rear face108may be rectangular. The gasket100may be formed of only one material. For example, the gasket100may be completely formed of neoprene, santoprene, or any other elastomeric material. Alternatively, the gasket100may be formed of any combination of these materials. The bug cover102may be formed or molded as a single piece with the gasket100and extend forward from the front face106. The bug cover102may be formed integrally with the gasket100. The bug cover102is configured to cover a cord port112of the electrical outlet cover104and allow an electrical cord (not shown) to pass through when the gasket100is installed in the electrical outlet cover104. In some embodiments, the bug cover102extends forward from a corner114of the front face106, as shown inFIG.1. In such embodiments, the bug cover102may also extend forward from the front face106on at least two sides116of the front face106as shown. Alternatively, the bug cover102may extend forward from the front face106on at least one side116of the front face106. The bug cover102may be configured to completely cover the cord port112of the electrical outlet cover104. Alternatively, the cord port112may only be partially covered by the bug cover102when the gasket100is installed in the electrical outlet cover104and the electrical outlet cover104is in the closed position. The bug cover102may have at least one slit118extending through the bug cover102. The at least one slit118allows an electrical cord to pass through the bug cover102. Thus, when an electrical outlet cover104has the gasket100installed and is in the closed position, the bug cover102covers the cord port112, but an electrical cord is still able to extend through the cord port112through the at least one slit118. Turning toFIGS.3-4, the gasket100may have a plurality of prong apertures120arranged surrounding the central aperture110. Each of the plurality of prong apertures120extends through the gasket100and is configured to receive a prong of a plurality of prongs of the electrical outlet cover104. The plurality of prongs helps to hold the gasket100in place once installed in the electrical outlet cover104. Additionally, the gasket100may comprise a plurality of troughs122in the rear face108. Each of the plurality of troughs122is aligned with a prong aperture120of the plurality of prong apertures120(seeFIG.3) and is configured to couple with an end of the prong when the prong extends through the prong aperture. For example, the end of the prong may have a larger cross-sectional area than the majority of the prong. When the prong is inserted into each of the prong apertures120, the end of the prong sits within the corresponding trough122and holds the prong within the prong aperture120. Turning toFIGS.5-6, the gasket100is configured to extend along an interface124between a base126and a lid128of the electrical outlet cover104and limit the entrance of water into the electrical outlet cover104through the interface124between the base126and the lid128when the gasket100is installed in the electrical outlet cover104and the lid128is in the closed position. As shown inFIG.5, when the lid128is in the closed position, the bug cover102covers the cord port112. FIG.7illustrates another embodiment of the gasket101. The gasket101may have the same features as the gasket100. However, the gasket101has a bug cover103which extends forward from the front face106on at least one side116of the front face106or at least two sides116of the front face106without extending forward from the corner114. As shown inFIG.8, and similar to the gasket100, the gasket101is configured to extend along an interface between a base127and a lid129of an electrical outlet cover105and limit the entrance of water into the electrical outlet cover105through the interface between the base127and the lid129when the gasket101is installed in the electrical outlet cover105and the lid129is in the closed position. When the lid129is in the closed position, the bug cover103covers the cord port113. It will be understood that implementations of a gasket-integrated bug cover are not limited to the specific assemblies, devices and components disclosed in this document, as virtually any assemblies, devices and components consistent with the intended operation of a gasket-integrated bug cover may be used. Accordingly, for example, although particular gasket-integrated bug covers, and other assemblies, devices and components are disclosed, such may include any shape, size, style, type, model, version, class, measurement, concentration, material, weight, quantity, and/or the like consistent with the intended operation of gasket-integrated bug covers. Implementations are not limited to uses of any specific assemblies, devices and components; provided that the assemblies, devices and components selected are consistent with the intended operation of a gasket-integrated bug cover. Accordingly, the components defining any gasket-integrated bug cover may be formed of any of many different types of materials or combinations thereof that can readily be formed into shaped objects provided that the components selected are consistent with the intended operation of a gasket-integrated bug cover. For example, the components may be formed of: polymers such as thermoplastics (such as ABS, Fluoropolymers, Polyacetal, Polyamide; Polycarbonate, Polyethylene, Polysulfone, and/or the like), thermosets (such as Epoxy, Phenolic Resin, Polyimide, Polyurethane, Silicone, and/or the like), any combination thereof, and/or other like materials; glasses (such as quartz glass), carbon-fiber, aramid-fiber, any combination thereof, and/or other like materials; composites and/or other like materials; metals, such as zinc, magnesium, titanium, copper, lead, iron, steel, carbon steel, alloy steel, tool steel, stainless steel, brass, nickel, tin, antimony, pure aluminum, 1100 aluminum, aluminum alloy, any combination thereof, and/or other like materials; alloys, such as aluminum alloy, titanium alloy, magnesium alloy, copper alloy, any combination thereof, and/or other like materials; any other suitable material; and/or any combination of the foregoing thereof. In instances where a part, component, feature, or element is governed by a standard, rule, code, or other requirement, the part may be made in accordance with, and to comply under such standard, rule, code, or other requirement. Various gasket-integrated bug covers may be manufactured using conventional procedures as added to and improved upon through the procedures described here. Some components defining a gasket-integrated bug cover may be manufactured simultaneously and integrally joined with one another, while other components may be purchased pre-manufactured or manufactured separately and then assembled with the integral components. Various implementations may be manufactured using conventional procedures as added to and improved upon through the procedures described here. Accordingly, manufacture of these components separately or simultaneously may involve extrusion, pultrusion, vacuum forming, injection molding, blow molding, resin transfer molding, casting, forging, cold rolling, milling, drilling, reaming, turning, grinding, stamping, cutting, bending, welding, soldering, hardening, riveting, punching, plating, and/or the like. If any of the components are manufactured separately, they may then be coupled with one another in any manner, such as with adhesive, a weld, a fastener (e.g. a bolt, a nut, a screw, a nail, a rivet, a pin, and/or the like), wiring, any combination thereof, and/or the like for example, depending on, among other considerations, the particular material forming the components. It will be understood that methods for gasket-integrated bug covers are not limited to the specific order of steps as disclosed in this document. Any steps or sequence of steps of the assembly of a gasket-integrated bug cover indicated herein are given as examples of possible steps or sequence of steps and not as limitations, since various assembly processes and sequences of steps may be used to assemble gasket-integrated bug covers. The implementations of a gasket-integrated bug cover described are by way of example or explanation and not by way of limitation. Rather, any description relating to the foregoing is for the exemplary purposes of this disclosure, and implementations may also be used with similar results for a variety of other applications employing a gasket-integrated bug cover. | 12,094 |
11862954 | While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not necessarily to limit the invention to the particular embodiments, aspects and features described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention and as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION Referring toFIGS.1-12, aspects of the junction boxes, systems and methods of the invention are shown. In one aspectFIG.1shows junction box20which includes a base22from which a wall30extends upward. The wall30defines a housing40in which wires and components may be positioned. Housing40has a top opening42for access. A lid50is positioned on the wall and covers the top opening42. In some aspects housing40has an open bottom or bottom opening44so that wires and components may readily extend into the housing40from below. In one aspect wall30includes a pin31which extends outward from an outer surface of the wall30. Pin31is received by a slot70defined by the lid50. Lid50sets upon wall30such that slot70receives pin31. While lid50moves downward upon junction box20, pin31slides within slot70. As described below, slot70is configured such that pin31secures lid70to the box20. Lid50has a top portion52and a panel54extending downward from the top portion52. Lid50is sized to fit over the top opening42. Panel54extends downward to cover at least a part of the outer surface of the wall30when the lid50is positioned on the wall30. In one aspect panel54includes a first portion55which defines slot70which receives pin31when lid50is placed on wall30. Panel54may also include a second portion56which defies slot72which receives pin33when lid50is placed on wall30. In aspects panel54also includes a third portion57which extends between first portion55and second portion56. Panel54may also include a fourth portion58and fifth portion59. FIG.2is an exploded view of junction box20showing lid50separated from wall30. When lid50is positioned on wall30, first portion55corresponds with first side35of wall30, second portion56with second side36of wall30, third portion57with third side37of wall30, fourth portion58with fourth side38of wall30and fifth portion59with fifth side39of wall30. In one aspect fourth side38and fifth side39form a peak41. Lid50also includes a peak41defined by fourth portion48and fifth portion59. Sides38and39are generally angled with respect to third side37and encourage water to run off sides38and39. Generally the sides35-39of wall30form a perimeter around or define housing space40. The sides35-39may include rounded or tapered upper areas to receive corresponding rounded or tapered areas of the underside of lid50.FIG.2shows junction box20where hosing40does not include a bottom but has a bottom opening44.FIG.3shows junction box20having a bottom45. Wires and components may be connected to bottom45. In one aspect, bottom45is integrally connected to base22. In other aspects, as shown inFIG.4, bottom45is connected to base22. In aspects junction box20may be manufactured from plastic including but not limited to hardened plastic, PVC, or other plastic material, or from metal, including but not limited to steel, stainless steel, aluminum, iron, or other metal, or of hybrid materials including but not limited to carbon fiber or alloys or fiberglass reinforced materials. In one aspect bottom45is integrally connected as part of base22as a single layer. In other aspects bottom45is connected to base22. Bottom45may be connected by welding, gluing, friction fit, adhesives, bonding or other connecting means. In one aspect lid50has a width of about 9.45 inches and a length of about 10.95 inches. In one aspect wall30includes a shoulder32which aligns around the wall and forms the top opening42. Shoulder32is a curved section which projects from wall30into the central area of housing40. In one aspect top opening42has a size of about 80 square inches. Other sized openings may be used as desired. In one aspect junction box20has a height of about 3.15 inches when lid50is positioned upon wall30. In one aspect about 1.7 inches of the wall30is exposed below the lid50when lid50is positioned upon wall30. In this manner the 1.7 inches is sufficient clearance for drilling holes into wall30for insertion of conduits into junction box20if desired. Having about 1.7 inches of exposed wall30allows for use of a M inch drill and conduit to be inserted into box20without having to drill into lid50if desired. Lid50also includes clearances53to allow for convenient drilling of holes into wall30and fitting of conduit into junction box20without having to also drill into lid50. In one aspect base22has a length of about 17.25 inches and a width of about 15.75 inches which accommodates for base22to slide under shingles or other roofing materials. FIG.4andFIG.5are side views of junction box20with lid50secured at wall30. As shown inFIG.5, lid50is configured to slide along wall30in the direction of Arrow “A” into a secured position. Slot70originates at an edge51of lid50and projects upward toward top portion52. After projecting upward toward top portion52, slot70transitions and forms a path in a direction aligned generally along edge51of lid50. In one aspect, slot70defines a “j” shaped path or an upside-down or inverted “J” shaped path, herein collectively considered “J-shaped”. In one aspect, slot70transitions and forms a path71in a direction away from a lower portion of panel54, such as third portion57, and in a direction opposite Arrow “A”. Having slot70with a terminal end73of its path71in direction opposite Arrow “A” allows for pin31(or a shank of pin31) to bottom-out or contact against lid50within slot70when lid70is slid in the direction of Arrow A. In one aspect, path71makes a right angle with respect to the opening or beginning at a widened portion72and the terminal end73of path71. In operation, lid50is placed downward upon wall30such that pin31is received in slot70at opening or widened portion72of slot70. The downward motion allows lid50to set upon wall30, and the sliding motion allows lid to be secured into position such that lid70is unable or at least somewhat limited from being rotated upward from wall30. Thus, lifting of lid50will not result in removal because pin31inhibits upward translation of lid50when pin31is positioned in the slot70adjacent a terminal end73. Unless lid50is slid in a direction opposite Arrow A, lid50is locked onto wall30. In aspects, when lid50is set into position as shown inFIG.4andFIG.5, fourth portion58and fifth portion59(SeeFIG.6) are positioned against wall30at fourth side38and fifth side39. In further aspects, when lid50is set into position as shown inFIG.4andFIG.5, lid50and wall30define a gap80. Gap80is configured to receive a spacer81to prevent lid50from sliding in a direction opposite Arrow A, thereby locking lid50to wall30. In one aspect spacer81is a fastener such as a screw or other fastener which is positioned within gap80. In other aspects spacer81is a fastener such as a screw or other fastener which passes through lid50and communicates with wall30. Spacer81may communicate with wall30by contacting wall30or passing into or through wall30. Spacer81may be threaded and insert into corresponding threads at wall30. Spacer81may also be a self-tapping fastener which may be drilled or screwed through lid50and into wall30. Wall30may include a preset hole for receiving spacer81. Lid50may also include a preset hole to receive spacer81. As shown inFIG.2andFIG.3, an installer may utilize a tool90such as a screwdriver to screw a fastener91through lid50and into wall30. The fastener91may be a screw having a washer or locking element or other hardware to secure the fastener91. Fastener91may also be a spacer81. In one aspect gap80has a width equal to the horizontal distance of path71, as measured from terminal end73to a center line of the widened portion. In one aspect, an inside surface of lid50, at third portion57will abut outside surface of wall30at third side37, while slot70aligns with pin31, and as lid50is placed on wall such that pin31travels into widened portion72and along the curve of path71, the inside surface of lid50separates from outside surface of third portion57to create gap80. When pin31bottoms out against terminal end73, gap80is set and ready to receive spacer81. In aspects, gap80need not be set when pin abuts terminal end73, such as when the lid50contacts fourth side38or fifth side39to stop further movement of lid50along wall30. In aspects, inside surface of lid50need not contact wall30before pin31is introduced into slot70. In some instances the size of gap80is configured such that spacer81must be fully removed from gap80in order for lid50to travel in the direction opposite Arrow A so that pin31also travels sufficiently along slot70for pin to be removed from slot70. In other aspects spacer81may be less than fully retracted from gap80to allow sufficient clearance for movement of lid50in the opposite direction so that pins31,33have clearance to slide along slots70and allow lid50to release upward from wall30. In aspects one-and-only-one spacer81or fastener91is positioned at gap80such that the lid50is removable from the wall30only upon adjustment of the single fastener91, which allows the lid to slide and release from the wall. Such single point adjustment for securing the lid provides ease of operation while accommodating secure locking of the lid50. No longer is it necessary to insert several screws through the lid to confidently secure it into position. In a further aspect, spacer81may be a material configured to friction-fit within gap80. Spacer81may include a rubberized or foam or plastic or yielding material which can be inserted upward into gap80to seal the gap and lock lid50into position. The spacer81may span a portion or an entirety of the length of gap80. Spacer81may be a sphere or other-shaped item which plugs into gap80. The spacer81may include a tab or string or handle so that an operator may easily pull downward on the spacer81to clear the gap80and allow for removal of lid50. In this manner, an installer may also secure lid50to wall30without the use of tools or hardware in cases where pins31,33are already present on wall30. In other aspects, an installer need only secure pins31,33into position and utilize a friction-fit spacer81(or fastening spacer81) for easy installation and use. Such features dramatically reduce the time and steps needed to install a junction box. The junction box20is also protective of the housing40from the environment. In further aspects, and in situations where a tool90is not required to open or remove lid50from wall30, junction box20may also include a dead front element positioned at the top opening42to prevent accidental insertion of a hand or object within housing40. In one aspect the dead front includes a panel or plate positioned at the top opening, and which panel may be selectively removed and replaced. In one aspect the dead front includes a polycarbonate panel which must be removed to access the housing40. In aspects the junction box20includes a three-point connecting system to secure the lid50to the wall30, where two of the three-point connecting elements include pins31,33connecting to the lid at opposite sides35,36of the box20and a third connecting element which includes a fastener connecting to the lid50at a side37of the wall30spanning between the opposite sides35,36of the junction box20, In further aspects the junction box20includes one and only one moving fastener91(or spacer81) configured to lock the lid50to the wall30such that lid50is unable to move upon wall30unless the moving fastener91(or spacer81) is adjusted. While junction box20may utilize pins31,33, in such aspect, pins31,33are stationary. In one aspect pin31is connected to or at first side35and a second pin33is connected to or at a second side36of wall30. Pins31,33may be connected to the outer surface of the wall30or may extend through the wall30. In one aspect pin31includes a head34connected to a shank62positioned at an outside of the wall30, and a nut64or fastener connected to the pin31at an inside of the wall30. In one aspect shank62includes a threaded portion to receive the nut to secure the pin31to wall30. In one aspect pin31is a shoulder bolt which may or may not include threads. Pin31may comprise other fasteners. Head34of pin31,33retains lid upon wall30. FIG.6is a top view of junction box20and shows pins31,33extending outward from wall30, andFIG.7is a front view also showing pins31,33.FIG.8is a partial view of junction box20with portions removed for clarity. Pin31includes a head34connected to a shank62. In one aspect the pin31passes through the first side35of wall30where it is secured by nut64. In aspects shank62is threaded and receives a threaded nut64to secure pin31to the wall30. Additional or alternative hardware may be used to secure pin31such that pin31extends outward from wall30. Pin31may also be welded or riveted into position. A portion of the shank62between the head34and nut64receives or inserts into the slot70. Head34has a size greater than a width of slot70. As shown inFIG.8there is sufficient space between head34and nut64to receive both first side35of wall30and first portion55of lid50. Shank62may have a length that is longer or shorter, and in some cases has a length such that first side35and first portion55fit snugly between head34and nut64, although some amount of spacing is desired to accommodate easy removal or replacement of lid50onto wall30. FIG.9is an exploded perspective view of a junction box20in accordance with a further aspect of the invention. Here, the pins31,33are positioned in the lid50while the slots70are provided at the wall30. Particularly, in one aspect slot70is formed at first side35of wall30. As shown inFIG.10, the slot70is “J”-shaped such that a wider opening is oriented at an upper area of the path71and narrows at the path forming the “J” shape and terminates at a terminal end73toward the third side37of wall30. The slot70is configured to receive the pin31from lid50. As the pin31inserts into slot70, it is directed downward and translated toward the terminal end73in the direction of Arrow A shown inFIG.10. FIG.11is a partial view of junction box20with portions removed for clarity. Pin31is secured to lid50at an inside area of the lid50. Particularly, in one aspect pin31is positioned so that head34is at an inside area of lid50while shank62passes through slot70. In aspects a nut64positioned at an outside area of lid50may secure upon shank62. In aspects shank62is threaded and receives a threaded nut64. Head34is configured to fit through a widened portion72of slot70while shank62moves within the narrowed path71of slot70. Head34is unable to fit through the narrowed path71. When the pin31(which is connected to lid50) slides within the slot70in the direction of Arrow A, the lid50is prevented from lifting upward from wall30. As shown inFIG.10, when lid50slides in the direction of Arrow A along wall30, the lid50is secured into a closed position and defines a gap80between a lower portion of lid50, such as third portion57, and third side37of wall30. Gap80is configured to receive a spacer81, such as a fastener91or other spacer which prevents the lid50from sliding in a direction opposite Arrow A. Thus, the lid50is fully locked into position upon wall30. In one aspect slot70is positioned at wall30such that the path71extends through the shoulder32of wall30. Shoulder32is a rounded aspect of wall30which projects toward a central area of housing40. In one aspect slot70originates at a terminal edge of the shoulder toward the central area. In other aspects, as shown inFIG.12, the slot70need not originate at a terminal edge of the shoulder. Widened portion72of slot70allows for clearance of head34to pass into slot70while the shank62is small enough to pass into the narrower portion of the slot70and travel to the terminal end73. It may be appreciated that junction box20shown inFIG.9may have two slots70, one as shown at first side35of wall30and another at second side36of wall30. The slot70at the second side36of wall may be similar to the slot70as shown inFIG.12positioned in part at the shoulder32and traveling downward in the J-shaped path to the second side36. In further aspect the invention includes a method of securing a lid50to a wall30where the wall30extends upward from a base22, the wall30defining a housing40having a top opening42. The lid has a top portion52and a panel54extending downwardly from the top portion52. The lid is sized to fit over the top opening42while the panel54covers at least a part of an outer surface of the wall30. As shown in aspects the panel54covers an outer surface of the wall30around an entire perimeter of the wall30. The method further comprises a step of sliding the lid50in a first direction, such as in the direction of Arrow A, along wall30to secure the lid50into a closed position upon the wall30. In the closed positioned the wall30and lid50define a gap50. The method further comprising a step of placing a spacer in the gap80which prevents the lid50from sliding the direction opposite Arrow A. In one aspect the step of placing a spacer in the gap80includes inserting a fastener into the lid50and in contact with the wall30. In one aspect the step of placing a spacer in the gap80includes utilizing a screwdriver to insert a screw into the lid50, through the gap80and into the wall30while pins31,33are positioned within slots70and against terminal ends73. In further aspects the invention includes a method of using a junction box20including positioning a lid50upon a wall30, the lid50having a top portion52and a panel54extending downwardly therefrom and covering at least a part of the outer surface of the wall30, the wall30extending upward from a base22and defining a cavity having a top opening42, and sliding the lid50along the wall30toward a lower portion of the panel54to define a gap80between the lower portion of the panel54and the wall30. In further aspect the method includes placing a spacer81into the gap80. In further aspects the method includes the base22extending outward from the wall30in all directions along a common plane, the junction box20including a bottom45in part defining the cavity. It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. | 18,767 |
11862955 | DETAILED DESCRIPTION While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. It is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. FIG.1is a top plan view of a battery current conductor100for use in a thruster power control box assembly, in accordance with some embodiments. The thruster power control box assembly will include two of these, which will be mirror images of each other along a vertical line to the left of the current conductor100shown here. The conductor100can be a plated copper bar that is configured to provide clearance inside the control box and to extend outside of the control box to obviate the need to open the control box. In the present example, the conductor bar100is deeper (i.e. into the page) than it is wide/thick. InFIG.2, for example, it can be seen that the present exemplary conductor bar is taller than it is thick (e.g. from side to side inFIG.1).FIGS.2-4show a side view, front view, and rear view of the conductor100, respectively. The conductor includes a battery connection end102that extends out of the control box and includes an aperture104for connecting to a battery cable (e.g., to the vessel battery). A connection end102is contiguous with a pass-through section106which passes through a plug bushing that seals around the conductor bar and the box, as will be shown. The pass-through section106is contiguous with a first angled section108and is angled relative to a general direction elongated direction of the pass-through section106and connection end102. The angle can be from forty five to ninety degrees in some embodiments, and more or less in other embodiments. The first angled section108routes the rest of the conductor bar100to the side of components in the thruster power control box, as will be shown herein. A side section110is contiguous with, and extends from the angled section108, and generally travels in a direction parallel to that of elongated direction of the pass-through section106and connector end102, but offset to the side so as to traverse along a side of the thruster power control box. At a distal end of the side section110, the conductor bar turns downward, along a downward section114, and a chamfered corner112is provided at the top of the conductor bar100. The downward section114can be as thick, side to side, as the other parts of the conductor bar100, and extends downward from the bottom of the distal end of the side section110. The downward section114is contiguous with an upward angled section116that rises at about a forty five degree angle in some embodiments, but can be at other angles. The upward angled section changes the orientation of the conductor bar100from having the width of the conductor bar100being vertically oriented in sections102,106,108,110, to being horizontally oriented in the upward angled section116and the flat terminal section118at the end of the upward angled section. An aperture120allows the end of the conductor bar to connect to the switch control in the thruster power control box assembly. The conductor bar100can have a thickness of about four millimeters, and a width (height) of about twelve to twenty millimeters in some embodiments, but those dimensions can vary by +/−50% in other embodiments. In general, the battery connecting end102of the conductor bars are configured to extend out of the thruster power control box, while the portion of the conductor bars inside the thruster power control box are generally routed around the main interior portion of the thruster power control box and circuitry. Further, the conductor bars have appropriate dimensions to carry a maximum load of current to be supplied to the thruster without introducing significant resistance in the circuit, which would power to the thruster and generates heat inside the thruster power control box. In general, the conductor bars100are pre-formed conductors configured to handle relatively large amounts of electric current without introducing substantial electrical resistance. Be pre-formed avoids the tasks of having to form a cable, for example, with equivalent electrical properties so that the cable is routed to the side of the thruster power control box. The conductor bars100can be cut from sheet metal of an appropriate gauge, and then drilled and bent by machine to the desired form factor, which makes assembly of the thruster power control box simpler and more efficient. It also ensures that, if an entity does open the box to service it after it has been installed on a vessel, the rigidity of the conductor bars will keep them in position, whereas if a cable portion were used instead, the servicing person may inadvertently move a cable to a point where it may contact a hot component, which could compromise the insulation (if any) and create an electrical hazard. FIG.5is a top perspective view of an open thruster power control box assembly500, in accordance with some embodiments.FIGS.6-8also provide other views of the box assembly500. InFIG.5the cover802of the base502of the housing is removed so that the internal components and their arrangement and configurations can be seen as an example of some arrangements consistent with the inventive embodiments. The housing is comprised of the base502and the cover802(seeFIG.8). The top of the walls of the box can include a gasket groove504or bed in which a gasket ring can be placed to seal the top of the base502to the lower part of the box cover802. Conductor bars100a,100bcan be seen routed along the sides of the base502, with the connector ends102a,102bextending out the front side of the base502past compression nuts506,508, respectively. Conductor bar100aextends through first conductor bushing530, and conductor bar100bextends through conductor bushing532. The conductor bushings530,532each pass through the front side of the housing502and are a tube structure with threads on the outside of the bushing. The conductor bushings530,532each have an anti-rotation nut534,538coupled to one end of the bushing that is inside of the housing. These are used to prevent the bushing from turning when a sealing nut536,540, respectively are tightened against a complaint washer on the bushing, between the sealing nut and the side of the housing. Further, the anti-rotation nuts534,538are used when tightening the compression nuts506,508, respectively, to prevent the bushings from turning. It can be seen that conductor bars100a,100bare mirror images of each other. The terminal sections118a,118bof the conductor bars100a,100bare fastened to the inputs519,521of a switch circuit518. Thruster cables510,512are coupled to the outputs526,528of the switch circuit518and pass through a thruster cable bushing522. In the present illustration, conductor bar100bcan be connected to the battery positive, and conductor bar100acan be connected to the battery negative. The switch circuit518directs current from the battery positive to one of the thruster cables, and the current returns through the other thruster cable, through the switch circuit to the battery negative. The direction of current thought the thruster cables is selected by operation of the thruster actuator control, which a user operates to select the direction of thrust. Signals from the actuator are provided through control cable514, which passes through thruster actuator bushing524(as seen inFIGS.6&7), and is connected to the switch control circuit520. Both direction and magnitude of current are controlled by the switch control circuit518to select the direction and speed of the thruster. A thermal sensor line516is connected to a temperature sensor in the thruster unit and a signal representing a thruster temperature, or temperature alarm, is provided to the switch control circuit520. If the thruster unit reaches an excessive temperature, as indicated by the signal carried by the thermal sensor line516, the switch control circuit520can shut off current to the thruster, despite operation of the thruster control actuator. InFIG.7the connector ends102a,102bcan be seen extending outward from respective bushings that are capped with compression nuts506,508. The connector ends102a,102bare separated by a suitable distance, such as about four centimeters, to prevent any electrical arcing between the connector ends102a,102bas well as to provide sufficient separation to reduce the chance of any incidental shorting by some other object. Disposed in each bushing is a compliant plug702,704, respectively through which the conductor bars100a,110bpass. The compliant plugs702,704can be silicone, for example, and the pass-through sections106of each of the conductor bars100a,100bpass through a passage in the respective plug702,704. The compression nuts506,508compress the end of the respective plugs702,704to ensure a seal around the conductor bars100a,100b. Likewise compression nuts on thruster cable bushing522and thruster actuator bushing524can act on compliant plugs seated in respective bushings through which the various cables pass. Similarly the control cable passes through a compliant plug525in a bushing on which compression nut524is threaded, and the thruster cables510,512and thruster temperature cable516pass through a plug523in a bushing522on which a compression nut is threaded. The compression nuts506,508on bushings530,532, and those on bushings522,524can be fit over their respective bushings to seal the openings through the bushings and to seal around the cables passing through the plugs523,525,702,704. InFIG.8, a side perspective view of the thruster power control box assembly500, it can be seen that the cover802fit on the lower portion502of the box assembly500. Screws804pass through the top vertically and into threaded receivers in the corners of the base502. The bottom of the base502includes a flange in which openings806are formed to allow mounting of the box assembly to a vessel. As mentioned herein above, a gasket sits between the cover802and the main box body502, in the gasket grove504. Keeping the box sealed is important to both exclude water, being on a boat, as well as to exclude fumes from inside the box in case of an electrical failure. FIG.9is a top view of a bushing530for supporting and sealing a battery current conductor. in particular, shown is an exploded overhead view of a portion of the front side of the base502at which the positive conductor bar100apasses through the front side of the base502. The threaded bushing530passes through an opening in the front side of the base502and can be threaded into the opening at one end of the bushing902by, for example, turning a anti-rotation nut534on the inner end of the bushing530. An outer sealing nut536can then be applied against a washer908that seals the opening through which the bushing530passes. The bushing530extends outward from the base502, and a distal end of the bushing530is formed into a series of fingers910that can deflect at their distal end. The fingers910can be formed by providing a series of slots into the end of the bushing530around the end of the bushing530. A compliant plug702fits snugly inside the bushing530and has a channel706that passes through the plug702. The is, the plug74has an outer diameter that is substantially equal to the inner diameter of the bore through the bushing530. In this example, as the bushing530is meant for a conductor bar, the conductor bar would be inserted through the channel706so that the battery connecting end102aextends outward from the plug704and the pass-through section106asits in the channel706. The compression nut508has a bore through it that is threaded to mate with the threads on outside of the bushing530. The compression nut508has a curved surface912on the inside near the outer end of the nut508, which is open. In general, the conductor bar is inserted through the plug704, and then the plug704can be inserted into the bushing530. The plug704, at its inner end, bears against a rim inside the bushing530and may extend slightly beyond the distal ends of the fingers910when seated in the bushing530. When the connector nut508is then tightened over the bushing530, the curved surface912urges the fingers910inward against the plug704thereby compressing the plug704against the conductor bar passing through channel706. A similar configuration can be used for the other bushings522,524,532for the other conductor bar, the thruster cables510,512and thermal sensor cable516, and the thruster actuator cable514. Thus, each of the bars or cables passing through bushings522,524,530,532are sealed against their respective plug by the respective bushings having distal fingers in combination with the compliant plug being compressed by the respective compression nut bearing on the distal fingers as the compression nut is tightened. As a result, the thruster power control box (e.g.502and802) forms a sealed enclosure that, while it keeps water out, more importantly it provides protection against ignition by also excluding vapor/fumes from the interior of the box. By sealing the box and providing the connections on the outside of the box, there is no need for an installer who is installing a thruster unit on a boat to open the box, which could compromise the integrity of the seal when the box is closed again. FIG.10is a block schematic diagram of a thruster power control circuit, in accordance with some embodiments. A switch circuit1002includes a switch tree comprised of four switches1004a-1004dincluding two input switches1004b,1004aat the top that are connected to the battery positive (B+) and the battery negative (B−) respectively. These input switches direct current through the output switches1004c,1004dat the bottom, which are connected to thruster cables T1and T2. If the B+ is connected to T1, then T2will be connected to B− to cause the thruster to produce thrust in one direction. To produce thrust in the opposite direction the B+ can be connected to T2, and T1can be connected to the B−. The switches1004a-1004dare controlled by a switch control circuit1008that is responsive to signals from the actuator control, and convert the signal from actuator control to switch states, and to throttle control1006. The switches1004control the direction of current flow, while the throttle control1006controls the magnitude of the current going to the thruster. Thus, the switch circuit1002has a first input (e.g. B+) and a second input (B−), and a first output (T1) and a second output (T2). The switch circuit1002is operable to selectively connect, in a first switch state, the first input to the first output and the second input to the second output, and in a second switch state connect the first input to the second output and the second input to the first output. The switch control circuit1008, responsive to the actuator input, determines which switch state to configure the switches. The switch control circuit1008can also be responsive to a thermal sensor input (thruster temperature) that restricts current to the thruster if the thruster reaches a preselected temperature in order to protect the thruster from thermal damage. In practice, the actuator can be a simple joystick device that can be moved left or right, corresponding to the desired direction of movement of the vessel, and the amount of movement can be proportional to the desired speed of the thruster. That is, the further the joystick is moved from its neutral position the faster the operator wants the thruster motor to turn, so the switch control circuit1008will respond by controlling the throttle control1006to regulate current through the thruster cables T1, T2by varying the resistance of switches1004c,1004d. Thus, pushing the joystick to the left or right cause the switch control circuit1008to configure the switches1004accordingly. The amount of deviation from the center position indicates the amount of thrust (throttle) that is desired. Those skilled in the art will recognize that thruster control is well known in the art, and there are numerous implementations of thruster control circuity and switching arrangements that can be used equivalently. Any prior art thruster control circuitry can be used in the thruster power control box assembly. FIG.11shows a top perspective view of a terminal box1100that can be used with the thruster power control box assembly to interconnect the thruster cables of the thruster power control box assembly with the cable of the thruster. Thruster cables510,512provide electric current to the thruster motor, but are terminated with connecting features that allow them to be connected to corresponding cables of the thruster. That is, thruster cables510,512are part of the thruster power control box assembly, and thus extend from the base502a short distance so as to be able to be electrically connected with the corresponding cable leads of the thruster. The terminal box1100is designed to connect the thruster cables510,512of the thruster power control box to the thruster cables that are connected to the thruster unit. The terminal box1100includes a cover1102and a base1104, and at the front include cable openings1106,1108through which a cable can pass. Similar openings to1106,1108are provided on the opposite side of the terminal box1100, which is hidden from view inFIG.11. A knob1122is connected to a threaded shaft which fastens the cover1102to the base1104. InFIG.12, the cover1102is removed showing the base1104and what is inside the terminal box1100. Openings1118,1120at the rear of the terminal box are formed by semicircular cutouts in the rear wall of the base1104. Likewise, similar semicircular cutouts are formed at the bottom of the rear wall of the cover to form a complete circular opening. Likewise with openings1106,1108at the front of the terminal box. A central wall1110runs across the middle of the base, from front to rear, extending upwards from the floor1105of the base1104, and the wall1110is high enough to meet the top of the cover1102when the cover1102is in place on the base1104. The central wall1110thus divides the interior of the terminal box into two sections, each with a front cable opening1106,1108and a rear cable opening1118,1120. In the approximate middle of each half, on each side of the central wall1110there are threaded studs1114,1116, which can be the shaft of a bolt that passes through the floor of the base. InFIG.13there is shown a cutaway view taken along a central section A-A′ passing from side to side of the terminal box, parallel to the front a rear walls. As can be seen, a threaded shaft1124is coupled to the knob1122and fit within the threaded bore1112of the central wall1110to fasten the cover1102onto the base1104. The threaded studs1114,1116can be seen as the shafts of bolts passing through the floor of the base. Each stud1114,1116can have one or more nuts1126,1128and washers (not shown). In connecting the thruster cables510,512, the end each of the cables510,512can pass through one of the rear openings1118,1120, respectively. The ends of the cables have flat connectors with a hole that is slightly larger than the diameter of the studs1114,1116to fit over the corresponding stud. Likewise, cables from the thruster can pass through the front openings and be connected to the studs1114,1116, thereby making an electric connection between the thruster cables of the thruster power control box assembly and the cables directly connected to the thruster. This is shown inFIG.14, where a first cable1402, which can be one of cables510,512, is terminated with an annular terminal1406, which has an opening through which the stud1116fits. Likewise, cable1404has a similar annular terminal1408that is also placed over the stud1116. A nut1128is than tightened against both of the terminals1406,1408to make an electrical connection between the two cables1402,1404. Once the cables on both sides of the terminal box are installed similar to that shown here, the cover1102can be installed on the base1104. The terminal box can have features that allow for mounting of the terminal box in a vessel. Further, the terminal box can be configured to be sealed, such as by providing compliant gasket components between the cover and the base, as well as at the cable openings, in order to prevent the ingress of both water and vapors. FIG.15shows a top perspective view of an open terminal box1500, andFIG.16shows a perspective view of the thruster power control box1100and the terminal box1500in an installed system. Box1500is similar to terminal box1100, but further provides for connections of one or more thermal sensor cables. A bottom1502of the box1500is shown with the top portion removed. The top portion1602is shown inFIG.16. Thruster cables510,512from the thruster power control box1100, along with thermal sensing cable516, are connected to terminals inside the terminal box1500. Cable510passes through opening1506in a first side of the box1500and is coupled onto terminal1528using connector1524, which terminates the thruster cable510and has a flat end with an opening through it so that the terminal1528can pass through the opening in the connector1524. Likewise, a thruster cable1512is connected to the thruster, and passes through the box at opening1508. Thruster cable1512likewise has a connector that fits onto terminal1528, in contact with connector1524. The connectors are metal, and therefore conductive. A nut1526presses a washer against the two connectors on terminal1528to provide a robust electrical contact between the connectors. Likewise, thruster cable512from the thruster power control box passes through opening1504in the terminal box1500, and has a connector1530that fits over terminal1534. Cable1514from the thruster passes through opening1510and also has a connector that fits onto terminal1534to be pressed into contact with connector1530by nut1532. Thus, cable510is electrically connected to cable1512at terminal1528, and cable512is electrically connected to cable1514at terminal1534. A central wall1516separates the two sides of the terminal box and runs between the terminals1528,1534. The wall extends upwards from the floor of the base inside the terminal box1500to meet the inside of the top1602of the terminal box1500. In addition, the thermal sensing cable516passes through an opening in the box1500and connects to a first terminal1522of connector block, which is connected to a second terminal1520to which a thermal sensing cable1518from the thruster unit is connected. Thus, the thermal signal from the thruster is conducted through the terminal box1500to the thruster power control box. The top portion1602can be secured to the bottom or base1502by, for example, fasteners1606,1608that pass through the top surface of the top portion1602and into threaded bores in the central wall1516. A marine thruster power control box assembly has been disclosed that eliminates the need for installers to open the box to make connections to the circuitry therein, reducing opportunities for damaging the thruster power control circuitry, and greatly simplifying the connection process. The disclosed thruster power control box assembly does this my mounting conductor bars for the batter positive and negative connections that pass through the box wall to connect to the switching circuitry inside the box. The conductor bars extend outside of the box, and are rigid so as to maintain separation between them. Inside the box the conductor bars area routed around the sides of the box on opposite sides in order to maximize access to the circuitry inside the box if a need arises to service the circuitry inside the box. | 23,925 |
11862956 | DETAILED DESCRIPTION The present disclosure provides exemplary embodiments of wire management clips. The wire management clips according to the present disclosure include multiple clip pockets and one or more cable pockets. The multiple clip pockets allow the wire management clip to be attached to a structure in different positions where lead-ins of the wire management clips face in different directions relative to the structure to which the clip is attached. The wire management clips may include one or more structure engaging members that improve the grip between a clip pocket and a portion of the structure to which the wire management clip is attached. The structure engaging members may be teeth, raised surfaces, ribs, tabs or other structures that can engage and grip the structure, or that can engage the structure and create a friction force or a friction fit between the wire management clip and the portion of the structure to which the wire management clip is attached. For ease of description, the wire management clips may also be referred to herein as the “clips” in the plural and the “clip” in the singular. The one or more wire management pockets are configured and dimensioned to receive and hold, for example, one or more cables or wires. The term “wire” is used herein in a general sense and refers to any type and size of electrical conductor. The wire may be a solid wire or a stranded wire. The wire may be insulated or non-insulated. The cable may be multiple wires encased within an outer jacket. The one or more cables or wires may also be collectively referred to herein as the “cables” in the plural and the “cable” in the singular. The structures that the wire management clips may be attached to include structures with short or long flanges extending therefrom or other structures with other extensions extending therefrom. Non-limiting examples of the structures that the wire management clips may be attached include frames of photovoltaic modules and rails of a photovoltaic arrays. The clips according to the present disclosure may be constructed from non-metallic materials or metallic materials that can flex when a force is applied to the clips as described in more detail below. Non-limiting examples of non-metallic materials include plastic, nylon and rubber. Non-limiting examples of metallic materials include spring steel and stainless steel. Referring toFIGS.1-8, an exemplary embodiment of a wire management clip according to the present disclosure is shown. The clip10includes one or more cable pockets and one or more clip pockets. In the exemplary embodiment shown there is a single cable pocket20and two clip pockets; a first clip pocket40and a second clip pocket60. As shown inFIGS.1-4, the cable pocket20is formed by a first arm22, a second arm24and a base26. The first arm22, the second arm24and the base26are configured and dimensioned to form an opening27that can receive and hold one or more cables. Continuing to refer toFIGS.1-4, the first arm22has a first end portion22aand a second end portion22b. The first end portion22aof the first arm22may be integrally or monolithically formed to one end26aof the base26. In another exemplary embodiment, the first end portion22amay be secured to the base26using fasteners, welds or adhesives. The second end portion22bof the first arm22is a free end that may include a lead-in28. The lead-in may be a rounded edge, a U-shaped like member, a V-shaped like member or other type of member that facilitates easier entry of cables into the opening27of the cable pocket20, that facilitates the flexing of the first arm22relative to the base26and/or that facilitates holding cables within the opening27of the cable pocket20. The lead-in28is in this exemplary embodiment is a U-shape like member with a curved member28aand a flared member28bthat facilitates flexing of the first arm22relative to the base26when inserting a cable into the cable pocket20. The second arm24has a first end portion24aand a second end portion24b. The first end portion24aof the second arm24may be integrally or monolithically formed to one end26bof the base26. In another exemplary embodiment, the first end portion24amay be secured to the base26using fasteners, welds or adhesives. The second end portion24bof the second arm24is a free end that may include a lead-in30. The lead-in30may be a rounded edge, a U-shaped like member, a V-shaped like member or other type of member that facilitates easier entry of cables into the cable pocket20, that facilitates the flexing of the second arm24relative to the base26, and/or that facilitates holding cables within the opening27of the cable pocket20. The lead-in30is in this exemplary embodiment a U-shape like member with a curved member30aand a flared member30bthat facilitates flexing of the second arm24relative to the base26when inserting a cable into the cable pocket20. While the lead-ins28and30are described herein as U-shaped like members, the present disclosure contemplates that the lead-ins may be in a number of different shapes and sizes, such as a rounded edge or V-shaped like member, that facilitate easier insertion of one or more cables into the cable pocket20, that facilitate the flexing of the first and second arms22and24relative to the base26, and/or that facilitate holding cables within the opening27of the cable pocket20. Further, the flared member28bof lead-in28and the flared member30bof lead-in30are bent away from each other, as shown inFIGS.3and4, to minimize and possibly prevent any sharp edges from coming into contact with cables received in, held by and/or withdrawn from the cable pocket20. Continuing to refer toFIGS.3and4, when the lead-ins28and30are in a normal state, there is a gap “G” between the curved member28aof the lead-in28and the curved member30aof the lead-in30. The gap “G” is generally smaller than a diameter of the one or more cables to be received into and held by the cable pocket20. Having a gap “G” that is smaller than a diameter of the one or more cables to be received into and held by the cable pocket20prevents the one or more cables from exiting the cable pocket20unless sufficient force is applied to the lead-in28to cause the first arm22to move away from the second arm24, and/or sufficient force is applied to the lead-in30to cause the second arm24to move away from the first arm22. For example, in instances where the clip pocket60is attached to a structure, seen inFIG.9, when the first arm22is urged away from the second arm24as shown by arrow B inFIGS.4and9, the gap “G” between the lead-in28and the lead-in30increases allowing one or more cables, e.g., cables600,602and604seen inFIG.9, to be inserted between the lead-ins28and30into the opening27of the cable pocket20, or allowing one or more cables, e.g., cables600,602and604, to be withdrawn from the opening27of the cable pocket20via the lead-ins28and30. Referring again toFIG.3, the first clip pocket40is formed by a first clip bracket42that may be integrally or monolithically formed into the first arm22, or secured to the first arm22by, for example, mechanical fasteners, welds or adhesives. The first clip bracket42is configured and dimensioned to create an opening44between a portion of the first clip bracket and the first arm22. In this exemplary embodiment, the first clip bracket42is an L-shape bracket where the short leg46of the first clip bracket42has one end that is integrally or monolithically formed into the first arm22. The height “H1” of the short leg46should be sufficient to permit a portion of a structure110, e.g., a flange112of the structure110seen inFIG.9, to fit into the opening44of the first clip pocket40. For example, if a thickness “T” of the flange112of the structure110is 1.5 mm, the height “H1” of the short leg46would be about 2.5 mm. The length “D1” of the long leg48of the first clip bracket42should be sufficient to permit a portion of the structure110, e.g., the flange112of the structure seen inFIG.9, to enter at least partially into the opening44in the first clip pocket40. For example, if a length “E” of the flange112of the structure110is 12 mm, the length “D1” of the long leg48would be at least about 6 mm. Referring toFIG.4, the second clip pocket60is formed by a second clip bracket62that may be integrally or monolithically formed into the second arm24, or secured to the second arm24by, for example, mechanical fasteners, welds or adhesives. The second clip bracket62is configured and dimensioned to create an opening64between a portion of the second clip bracket62and the second arm24. In this exemplary embodiment, the second clip bracket62is an L-shape bracket where the short leg66of the second clip bracket62has one end that is integrally or monolithically formed into the second arm24. The height “H2” of the short leg66should be sufficient to permit a portion of the structure110, e.g., the flange112of the structure110seen inFIG.11, to fit into the opening64of the second clip pocket60. For example, if a thickness “T” of the flange112of the structure110is 1.5 mm, the height “H2” of the short leg46would be about 2.5 mm. It is noted that the height “H1” and “H2” may be the same or they may be different such that one height may accommodate one structure thickness and the other height may accommodate another structure thickness. The length “D2” of the long leg68of the second clip bracket62should be sufficient to permit a portion of the structure110, e.g., the flange112of the structure seen inFIG.11, to enter at least partially into the opening64in the second clip pocket60. For example, if a length “E” of the flange112of the structure110is 12 mm, the length “D2” of the long leg68would be about at least 6 mm. It is noted that the length “D1” and “D2” may be the same or they may be different such that one length may accommodate one structure length and the other length may accommodate another structure length. Referring toFIGS.1,5,7and8, to help facilitate a tighter grip between the first clip pocket40and, for example, the flange112of the structure110, the first arm22may include one or more structure engaging members70that extend away from the first arm22in a direction toward a plane associated with the long leg48of the first clip bracket42. The one or more structure engaging members70may be provided to improve the grip between the first clip pocket40and a portion of the structure, e.g., structure110, to which the wire management clip10is to be attached. The structure engaging members70may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, e.g., structure110seen inFIG.9, or that can engage the structure and create a friction force or a friction fit between the wire management clip10and the portion of the structure to which the wire management clip is attached. Referring toFIGS.2,6,7and8, to help facilitate a tighter grip between the second clip pocket60and, for example, the flange112of the structure110, the second arm24may include one or more structure engaging members72that extend away from the second arm24in a direction toward a plane associated with the long leg68of the second clip bracket62. The one or more structure engaging members72may be provided to improve the grip between the second clip pocket60and a portion of the structure, e.g., structure110, to which the wire management clip10is to be attached. The structure engaging members72may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, e.g., structure110seen inFIG.9, or that can engage the structure and create a friction force or a friction fit between the wire management clip10and the portion of the structure to which the wire management clip is attached. Referring again toFIGS.3and4, the clip pockets40and60are oriented on their respective arms22or24to allow the clip10to be attached to a structure, e.g., structure110, in different positions where the opening of the clip pocket is accessible from different sides or ends of the clip10. For example, the first clip pocket40may be oriented relative to the first arm22so that the opening44is accessible from the base26end of the clip10, as shown. With the first clip pocket40accessible from the base26end of the clip10, the second clip pocket60may be oriented relative to the second arm24so that the opening64is accessible from the lead-in end of the clip10, as shown. In another exemplary embodiment, the first clip pocket40may be oriented relative to the first arm22so that the opening44is accessible from a left or right side of the clip10. With the first clip pocket40accessible from a left or right side of the clip10, the second clip pocket60may be oriented relative to the second arm24so that the opening64is accessible from the right or left side of the clip10respectfully. As set forth above, the clip pockets40and60are oriented so that the clip10can be attached to a structure in different positions. As shown inFIG.9, the clip10is attached to the flange112of the structure110so that the clip is below the flange and the lead-ins28and30are facing in a direction toward a back wall114of the structure110. To attach the clip10to the flange112, the opening64of the clip pocket60is aligned with the flange and force is applied to, for example, the base26of the clip pocket20in the direction of the back wall114. As the clip pocket60is pressed onto the flange112, the structure engaging members72engage the bottom surface112aof the flange and grasps the flange to attach the clip10to the flange. In the exemplary embodiment of the clip10ofFIG.1, the structure engaging members72have a pointed tip that may pierce any non-conductive coatings on the flange112so that the clip10may be electrically bonded to the structure110, as seen inFIG.11. With the clip10attached to the flange112, cables600,602and604can be inserted into the opening27of the cable pocket20. When inserting the cables, e.g., cable604, into the opening27, the cable contacts the flared member28bof the lead-in28and the flared member30bof the lead-in30and rides along the flared members28band30bcausing the first arm22to flex in the direction of arrow “B” so that gap “G” increases sufficient to permit the cable604to pass into the opening27, as seen inFIG.10. Once the cable passes the curved member28aand the curved member30aof the respective lead-ins28and30, the force applied to the lead-ins28and30is removed allowing the first arm22to return to its normal state. At this point the gap “G” decreases to its normal state holding the cables600,602and604within the opening27of the cable pocket20. As shown inFIG.12, the clip10is attached to the flange112of the structure110so that the clip is above the flange and the lead-ins28and30are facing toward the back wall114of the structure110. In this exemplary embodiment, the cables600and602are first inserted into the opening27of the cable pocket20. When inserting the cables, e.g., cable602, into the opening27, the cable contacts the flared member28bof the lead-in28and the flared member30bof the lead-in30and rides along the flared members28band30bcausing the first arm22to flex in the direction of arrow “B” and the second arm24to flex in the direction of arrow “A” so that gap “G” increases sufficient to permit the cable to pass into the opening27, as seen inFIG.13. Once the cable passes the curved member28aand the curved member30aof the respective lead-ins28and30, the force applied to the lead-ins28and30is removed allowing the first arm22and the second arm24to return to their normal state. At this point the gap “G” decreases to its normal state holding the cables600and602within the opening27of the cable pocket20. With the cables in the cable pocket20, the clip10can then be attached to the flange112. To attach the clip10to the flange112, the opening64of the second clip pocket60is aligned with the flange112and force is applied to, for example, the base26of the clip pocket20in a direction toward the back wall114. As the clip pocket60is pressed onto the flange112, the structure engaging members72engage the bottom surface112aof the flange112and grasp the flange to attach the clip10to the flange112. In the exemplary embodiment of the clip10ofFIG.1, the structure engaging members72have a pointed tip that may pierce any non-conductive coatings on the flange112so that the clip10may be electrically bonded to the structure110. As shown inFIG.14, the clip10may be attached to a structure in different position. As shown, the clip10can be attached to the flange112of the structure110so that the clip is below the flange and the lead-ins28and30are facing in a direction away from the back wall114of the structure110. To attach the clip10to the flange112, the opening44of the clip pocket40is aligned with the flange and force is applied to, for example, the lead-ins28and30of the clip pocket20in a direction toward the back wall114. As the clip pocket40is pressed onto the flange112, the structure engaging members70engage the bottom surface112aof the flange112and grasps the flange to attach the clip10to the flange. In the exemplary embodiment of the clip10ofFIG.1, the structure engaging members70have a pointed tip that may pierce any non-conductive coatings on the flange112so that the clip10may be electrically bonded to the structure110. With the clip10attached to the flange112, cables600,602and604can be inserted into the opening27of the cable pocket20. When inserting the cables, e.g., cable604, into the opening27the cable contacts the flared member28bof the lead-in28and the flared member30bof the lead-in30and rides along the flared members28band30bcausing the second arm24to flex in the direction of arrow “A” so that gap “G” increases sufficient to permit the cable604to pass into the opening27. Once the cable passes the curved member28aand the curved member30aof the respective lead-ins28and30, the force applied to the lead-ins28and30is removed allowing the second arm24to return to its normal state. At this point the gap “G” decreases to its normal state holding the cables600and602within the opening27of the cable pocket20. As shown inFIG.15, the clip10is attached to the flange112of the structure110so that the clip is above the flange and the lead-ins28and30are facing in a direction away from the back wall114of the structure110. To attach the clip10to the flange112, the opening44of the clip pocket40is aligned with the flange and force is applied to, for example, the lead-ins28and30of the clip pocket20in a direction toward the back wall114. As the clip pocket40is pressed onto the flange112, the structure engaging members70engage the top surface112bof the flange112and grasps the flange to attach the clip10to the flange. In the exemplary embodiment of the clip10ofFIG.1, the structure engaging members70have a pointed tip that may pierce any non-conductive coatings on the flange112so that the clip10may be electrically bonded to the structure110. With the clip10attached to the flange112, cables600and602can be inserted into the opening27of the cable pocket20. When inserting the cables, e.g., cable602, into the opening27, the cable contacts the flared member28bof the lead-in28and the flared member30bof the lead-in30and rides along the flared members28band30bcausing the second arm24to flex in the direction of arrow “B” so that gap “G” increases sufficient to permit the cable to pass into the opening27. Once the cable passes the curved member28aand the curved member30aof the respective lead-ins28and30, the force applied to the lead-ins28and30is removed allowing the second arm24to return to its normal state. At this point the gap “G” decreases to its normal state holding the cables600and602within the opening27of the cable pocket20. Referring toFIGS.16-19, another exemplary embodiment of a wire management clip according to the present disclosure is shown. In this exemplary embodiment, the clip80is substantially the same as clip10described so that the same reference numerals are used for the same elements, and for ease of description the same elements will not be described again. In this exemplary embodiment, the clip80includes a cable arm82extending from the first arm22into the opening27of the cable pocket20and a slot23in the first arm22and a slot43in the first clip bracket42through which the cable arm82can pass. The cable arm82is provided to help retain the cable or cables, e.g., cables602and604, within the opening27of the cable pocket20, as seen in FIGS.,18and19. More specifically, the cable arm82has a spring like function in that the cable arm82extends into the opening27in a normal state and can flex toward the first arm22when cables are inserted into the opening27of the cable pocket20and spring back toward the normal state once the cable passes the lead-ins28and30. The cable arm82has a first leg84with one end integrally or monolithically formed into the first arm22or secured to the first arm22by, for example, mechanical fasteners, welds or adhesives. The first leg84is formed into or secured to the first arm22at an angle relative to the long axis of the first arm22so that the first leg84is within the into the opening27. The cable arm82also includes a second leg86has one end that is formed into or secured to a second end of the first leg84and a free end, as shown. The second leg86may be a curved or rounded structure that distances the free end of the second leg86away from contacting the cables within the opening27of the cable pocket20. Turning now toFIGS.20-22, another exemplary embodiment of a wire management clip according to the present disclosure is shown. The clip100includes one or more cable pockets and one or more clip pockets. In this exemplary embodiment there is a single cable pocket20and two clip pockets; a first clip pocket40and a second clip pocket60. The cable pocket20is the same as the cable pocket described above and for ease of description is not repeated. The first clip pocket40is substantially the same as the first clip pocket described above, except that the long leg48of the first clip bracket42includes one or more second structure engaging members76. In this exemplary embodiment, the one or more second structure engaging members76may be one or more raised surfaces extending from the long leg48of the first clip bracket42into the opening44of the first clip pocket40. Similarly, the second clip pocket60is substantially the same as the second clip pocket described above, except that the long leg68of the second clip bracket62includes one or more second structure engaging members78. In this exemplary embodiment, the one or more second structure engaging members78may be one or more raised surfaces extending from the long leg68of the second clip bracket68into the opening64of the second clip pocket60. The second structure engaging members76and78may be provided to further enhance the attachment of the clip100to the structure, e.g., structure110, by increasing the friction force or a friction fit between first and second clip brackets40and60and the structure. It is noted that the second structure engaging members76and78may include knurling or other surface roughing to further increase the friction force between first and second clip brackets40and60and the structure. It is also noted that the second structure engaging members76and78may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, or that can engage the structure and create a friction force or a friction fit between the wire management clip100and the portion of the structure to which the wire management clip is attached. Turning now toFIGS.23-25, another exemplary embodiment of a wire management clip according to the present disclosure is shown. The clip200includes one or more cable pockets and one or more clip pockets. In this exemplary embodiment the first clip pocket40and a second clip pocket60are the same as the first and second clip pockets described above and for ease of description are not repeated. In this exemplary embodiment there is a single cable pocket20that is substantially the same as the cable pocket described above, except the one or more structure engaging members70include one or more raised surfaces that extend away from the first arm22in a direction toward a plane associated with the long leg48of the first clip bracket42. Similarly, the one or more structure engaging members72include one or more raised surfaces that extend away from the second arm24in a direction toward a plane associated with the long leg68of the second clip bracket62. In the exemplary embodiment shown, each of the one or more structure engaging members70is a single raised surface, and each of the one or more structure engaging members72includes a plurality of raised surfaces. However, the present disclosure contemplates that the first arm22may include a plurality of raised surfaces instead of a single raised surface, and that the second arm24may include a single raised surface instead of plurality of raised surfaces. Referring toFIGS.26-28, another exemplary embodiment of a wire management clip according to the present disclosure is shown. The clip300includes one or more cable pockets and one or more clip pockets. In this exemplary embodiment there is a single cable pocket20and two clip pockets; a first clip pocket40and a second clip pocket60. The cable pocket20is substantially the same as the cable pocket described above, except the first arm22does not include one or more structure engaging members70, and the second arm24does not include one or more structure engaging members72. In this exemplary embodiment, the first clip pocket40is substantially the same as the first clip pocket described above, except that the long leg48of the first clip bracket42includes the one or more structure engaging members70. The one or more structure engaging members70may be provided to improve the grip between the first clip pocket40and a portion of the structure, e.g., structure110, to which the clip300is to be attached. The structure engaging members70may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, or that can engage the structure and create a friction force between the clip300and the portion of the structure to which the wire management clip is attached. In this exemplary embodiment, the one or more structure engaging members70include two pointed edges extending from the long leg48of the first clip bracket42into the opening44of the first clip pocket40. Similarly, the second clip pocket60is substantially the same as the second clip pocket described above, except that the long leg68of the second clip bracket62includes the one or more structure engaging members72. The one or more structure engaging members72may be provided to improve the grip between the second clip pocket60and a portion of the structure, e.g., structure110, to which the clip300is to be attached. The structure engaging members72may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, or that can engage the structure and create a friction force or a friction fit between the clip300and the portion of the structure to which the wire management clip is attached. In this exemplary embodiment, the one or more structure engaging members72include two pointed edges extending from the long leg68of the second clip bracket62into the opening64of the second clip pocket60. Referring toFIGS.29-31, another exemplary embodiment of a wire management clip according to the present disclosure is shown. The clip400includes one or more cable pockets and one or more clip pockets. In this exemplary embodiment there is a single cable pocket20and two clip pockets; a first clip pocket40and a second clip pocket60. The cable pocket20is the same as the cable pocket described above and for ease of description is not repeated. The first clip pocket40is substantially the same as the first clip pocket described above, except that the long leg48of the first clip bracket42includes one or more second structure engaging members76. The one or more second structure engaging members76may be provided to further improve the grip between the first clip pocket40and a portion of the structure, e.g., structure110, to which the clip400is to be attached. The second structure engaging members76may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, or that can engage the structure and create a friction force between the clip400and the portion of the structure to which the clip is attached. In this exemplary embodiment, the one or more second structure engaging members76include two pointed edges extending from the long leg48of the first clip bracket42into the opening44of the first clip pocket40. Similarly, the second clip pocket60is substantially the same as the second clip pocket described above, except that the long leg68of the second clip bracket62includes one or more second structure engaging members78. The one or more second structure engaging members78may be provided to further improve the grip between the first clip pocket40and a portion of the structure, e.g., structure110, to which the clip400is to be attached. The second structure engaging members78may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, or that can engage the structure and create a friction force or a friction fit between the clip400and the portion of the structure to which the clip is attached. In this exemplary embodiment, the one or more second structure engaging members78include two pointed edges extending from the long leg68of the second clip bracket62into the opening64of the second clip pocket60. Turning now toFIGS.32-35, another exemplary embodiment of a wire management clip according to the present disclosure is shown. The clip450includes one or more cable pockets and one or more clip pockets. In the exemplary embodiment shown, there is a single cable pocket452and single clip pocket490. In this exemplary embodiment, the cable pocket452is rotatable relative to the clip pocket490to permit adjustment of the position of the clip450relative to the structure to which the clip is to be attached. As shown inFIGS.32-34, the cable pocket452is formed by a first arm456, a second arm458and a base460. The first arm456, the second arm458and the base460are configured and dimensioned to form an opening462that can receive and hold one or more cables. Continuing to refer toFIGS.32-34, the first arm456has a first end portion456aand a second end portion456b. The first end portion456aof the first arm456may be integrally or monolithically formed to one end460aof the base460. In another exemplary embodiment, the first end portion456amay be secured to the base460using fasteners, welds or adhesives. The second end portion456bof the first arm456is a free end that may include a lead-in464. The lead-in may be a rounded edge, a U-shaped like member, a V-shaped like member or other type of member that facilitates easier entry of cables into the opening462of the cable pocket452, that facilitates the flexing of the first arm456relative to the base460and/or that facilitates holding cables within the opening462of the cable pocket452. The lead-in464is in this exemplary embodiment is a U-shape like member with a curved member464aand a flared member464bthat facilitates flexing of the first arm456relative to the base460when inserting a cable into the cable pocket452. The second arm458has a first end portion458aand a second end portion458b. The first end portion458aof the second arm458may be integrally or monolithically formed to one end460bof the base460. In another exemplary embodiment, the first end portion458amay be secured to the base460using fasteners, welds or adhesives. The second end portion458bof the second arm458is a free end that may include a lead-in466. The lead-in466may be a rounded edge, a U-shaped like member, a V-shaped like member or other type of member that facilitates easier entry of cables into the cable pocket452, that facilitates the flexing of the second arm458relative to the base460, and/or that facilitates holding cables within the opening462of the cable pocket452. The lead-in466is in this exemplary embodiment a U-shape like member with a curved member466aand a flared member466bthat facilitates flexing of the second arm458relative to the base460when inserting a cable into the cable pocket452. While the lead-ins464and466are described herein as U-shaped like members, the present disclosure contemplates that the lead-ins may be in a number of different shapes and sizes, such as a rounded edge or V-shaped like member, that facilitate easier insertion of one or more cables into the cable pocket452, that facilitate the flexing of the first and second arms456and458relative to the base460, and/or that facilitate holding cables within the opening462of the cable pocket452. Further, the flared member464bof lead-in464and the flared member466bof lead-in466are bent away from each other, as shown inFIG.32, to minimize and possibly prevent any sharp edges from coming into contact with cables received in, held by and/or withdrawn from the cable pocket452. Continuing to refer toFIG.32, when the lead-ins464and466are in a normal state, there is a gap “G” between the curved member464aof the lead-in464and the curved member466aof the lead-in466. The gap “G” is generally smaller than a diameter of the one or more cables to be received into and held by the cable pocket452. Having a gap “G” that is smaller than a diameter of the one or more cables to be received into and held by the cable pocket452prevents the one or more cables from exiting the cable pocket452unless sufficient force is applied to the lead-in464to cause the first arm456to move away from the second arm458, and/or sufficient force is applied to the lead-in466to cause the second arm458to move away from the first arm456. For example, in instances where the clip pocket490is attached to a structure, seen inFIG.35, when the second arm458is urged away from the first arm456, the gap “G” between the lead-in464and the lead-in466increases allowing one or more cables, e.g., cables602and604seen inFIG.18, to be inserted between the lead-ins464and466into the opening462of the cable pocket452, or allowing one or more cables, e.g., cables602and604, to be withdrawn from the opening462of the cable pocket452via the lead-ins464and466. Referring again toFIGS.32and33, the clip pocket490in this exemplary embodiment is a U-shaped member that is formed by a first clip arm492, a second clip arm494and a third clip arm496integrally formed or secured to one end of the first clip arm492and the second clip arm494such that the first clip arm492is spaced from the second clip arm494to create an opening498therebetween. In this exemplary embodiment, he height “H2” of the third clip arm496defines the height of the opening498which should be sufficient to permit a portion of a structure, e.g., a flange112of the structure110seen inFIG.35, to fit into the opening498of the clip pocket490. For example, if a thickness “T” of the flange112of the structure110is 1.5 mm, the height “H2” of the third clip arm496would be about 2.5 mm. The length “D3” of the first clip arm492and the length “D4” of the second clip arm494should be sufficient to permit a portion of the structure, e.g., the flange112of the structure seen inFIG.35, to enter at least partially into the opening498in the clip pocket490. For example, if a length “E” of the flange112of the structure110, seen inFIG.9, is 12 mm, the lengths “D3” and “D4” would be at least about 6 mm. It is noted that the length “D3” of the first clip arm492and the length “D4” of the second clip arm492may be the same, or they may differ. Either one or both the first clip arm492and the second clip arm494may include one or more structure engaging members500that extend away from the respective clip arm492and/or494into the opening498. The one or more structure engaging members500may be provided to improve the grip between the clip pocket490and the portion of the structure, e.g., flange112, to which the wire management clip450is to be attached. The structure engaging members500may be one or more teeth or pointed edges, one or more tabs or ribs, one or more raised surfaces or other structures that can engage and grip the structure, e.g., flange112seen inFIG.35, or that can engage the structure and create a friction force or a friction fit between the wire management clip450and the portion of the structure to which the wire management clip is attached. As noted above, in this exemplary embodiment, the cable pocket452is rotatable relative to the clip pocket490to permit adjustment of the position of the clip450lead-ins464and466relative to the structure to which the clip is to be attached. The present disclosure contemplates the numerous known techniques in which one member can be connected to another member such that the two members are rotatable relative to each other. In the exemplary embodiment shown inFIGS.33and34, a ball and socket like configuration is used to make the cable pocket452rotatable relative to the clip pocket490. More specifically, second clip arm494includes a ball510extending away from the second clip arm494as shown inFIG.33. The ball510has a diameter “D5” and forms the ball portion of the ball and socket configuration. To form the socket portion of the ball and socket configuration, the first arm456of the cable pocket452includes a socket housing512extending away from the first arm456as shown. The socket housing512has an aperture514through which the ball510of the clip pocket490can be press through. It is noted that the socket housing512may be a hollow housing, as shown inFIG.34, or the socket housing512may be a solid housing with a bore for receiving the ball510. A top portion514aof the aperture514may be tapered to help align the ball510with the aperture514. In the exemplary embodiment shown, the socket housing512is a hollow housing. The aperture514of the socket housing512has a diameter “D6” that is less than the diameter “D5” so that when the ball510is pressed through the socket aperture514the ball remains within the socket housing512such that the ball510is movable within the socket housing512. As a result, the cable pocket452is movable, e.g., rotatable, relative to the clip pocket490. Referring toFIG.35, to attach the clip450to the flange112, the opening498of the clip pocket490is aligned with the flange and force is applied to, for example, the third clip arm496of the clip pocket490in the direction of the back wall114of the structure110. As the clip pocket490is pressed onto the flange112, the structure engaging members500, seen inFIG.33, engage the bottom surface112aof the flange and grasps the flange to attach the clip450to the flange. In the exemplary embodiment of the clip450ofFIGS.32-35, the structure engaging members500have a pointed tip that may pierce any non-conductive coatings on the flange112so that the clip450may be electrically bonded to the structure110, as described herein above. With the clip450attached to the flange112, the cable pocket452can be rotated so that the lead-ins464and466face a desired direction relative to the flange112, as shown inFIG.35. To hold the cable pocket452in the set position relative to the clip pocket490, a rotational stop516may be used. Examples of rotational stops include ball detents mechanisms, pawl and ratchet mechanisms, slide stop mechanisms, and detent/indent stop mechanisms. In the exemplary embodiment shown, the rotational stop516is a detent/indent stop. More specifically, the outside surface512aof the socket housing512may include one or more indents518, seen inFIGS.33and34, and the outside surface494aof the second clip arm494may include one or more detents520aligned to coincide with the one or more indents518so that a detent520can rest within an indent518, as seen inFIG.34, to hold the cable pocket452in the set position relative to the clip pocket490. Once the cable pocket452is in a set position, cables, e.g., cables602and604, can be inserted into the opening462of the cable pocket452. When inserting the cables into the opening462, the cable contacts the flared member464bof the lead-in464and the flared member466bof the lead-in466and rides along the flared members464band466bcausing the second arm458of the clip pocket452to flex in the direction of arrow “C” so that gap “G” increases sufficient to permit the cable604to pass into the opening462. Once the cable passes the curved member464aand the curved member466aof the respective lead-ins464and466, the force applied to the lead-ins464and466is removed allowing the second arm458to return to its normal state. At this point the gap “G” decreases to its normal state holding the cables within the opening462of the cable pocket452. While illustrative embodiments of the present disclosure have been described and illustrated above, it should be understood that these are exemplary of the disclosure and are not to be considered as limiting. Additions, deletions, substitutions, and other modifications can be made without departing from the spirit or scope of the present disclosure. Accordingly, the present disclosure is not to be considered as limited by the foregoing description. | 41,826 |
11862957 | DETAILED DESCRIPTION In this Detailed Description, and the Claims below, and in the accompanying drawings, reference is made to particular features, including process steps, of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with/or in the context of other particular aspects of the embodiments of the invention, and in the invention generally. Where reference is made herein to a process comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously (except where the context excludes that possibility), and the process can include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all the defined steps (except where the context excludes that possibility). The term “comprises” and grammatical equivalents thereof are used herein to mean that other components, steps, etc. are optionally present. For instance, a system “comprising” components A, B, and C can contain only components A, B, and C, or can contain not only components A, B, and C, but also one or more other components. The term “at least one of . . . and” and grammatical equivalents thereof are used herein to mean that at least one of a group of items is present but more components of that group can be present. For instance, a system comprising at least one of components A, B, and C can contain only components A and B, or can contain multiple components A and C, but only one of component B. As used herein, the term “at least one” and grammatical equivalents thereof are used herein to mean that one or more of an item is present. For instance, at least one magnet means that an embodiment exists with a single magnet as well embodiments with multiple magnets. FIGS.1A-9illustrate embodiments of a folding, flared utility vault or enclosure that may be used to protect public utility valves, electrical cables, switches, fiber optic cables, or the like. It is understood that the various method steps associated with the methods of the present disclosure may be carried out by a worker805using the device100shown inFIGS.1A-8. The system100generally comprises a base box105. Alternative embodiments further comprise an extension box110. The base box105comprises a front panel106, back panel107, and side panels. The extension box110comprises a front extension panel111, back extension panel112, and side extension panels. As illustrated inFIGS.1A-8, the front panel106, back panel107, first side panel108, and second side panel109of the base box105and the front extension panel111, back extension panel112, first side extension panel113, and second side extension panel114of the extension box110may be attached to one another via a hinge115. In other embodiments, the base box105is utilized on its own without the extension box110. As illustrated inFIGS.1A-7, the device100is a fully functional enclosure system100. A lid135, as illustrated inFIG.6, may attach directly to the top of the base box105. In another embodiment, a floor may be attached to the bottom of the base box105and/or extension box110to compartmentalize areas within the utility vault. The extension box110may be attached to the base box105prior to or after installation. In a preferred embodiment, the extension box110is added after initial installation of the base box105, which is one method of increasing the interior space of a vault. As illustrated inFIGS.1A and1B, the hinges115may allow the base box105and extension box110to fold so that they may be more easily transported.FIGS.2and3illustrate front views and back views of the device100, respectively. In particular,FIGS.2and3illustrate the features of the exterior surfaces of the front panel106, back panel107, front extension panel111, and back extension panel112.FIGS.4and5illustrate side views of the base box105and extension box110. In particular,FIGS.4and5illustrate the features of the exterior surfaces of the first side panel108, second side panel109, first side extension panel113, and second side extension panel114.FIG.6illustrates a top view of an embodiment of the base box105and extension box110with and without a lid135.FIG.7illustrates a bottom view of the base box105and extension box110with and without a lid135.FIG.8illustrates how one might use the device100in an environment800.FIG.9illustrates a method that may be carried out by a worker805using the folding, flared utility vault. As illustrated inFIGS.1A and1B, the base box105and extension box110may be connected and may be folded via hinges115that connect their respective panels. In other embodiments, the base box105is not connected to the extension box110, as illustrated inFIG.1B, but instead functions alone. In a preferred embodiment, the hinge115is formed by a plurality of side knuckles116attached to the edges of the various panels of the base box105and extension box110. The side knuckles116have an aperture117that extends from the top end128to the bottom end121of the base box105. The side knuckles further include an aperture117that extends from the top end128to the bottom end121of the base box105and/or extension box110. In one preferred embodiment, the edges of the panels may be angled such that the side knuckles116may rotate freely without contacting another panel, as illustrated inFIGS.1A and1B. A hinge mechanism may be inserted into the apertures117of the base box105and/or extension box110to hold the side knuckles116rotatable in place. In a preferred embodiment, the hinge mechanism is a pin. When the base box105and extension box110are connected together, they fold about said hinge mechanism. In one preferred embodiment, the apertures117of the side knuckles116has a diameter slightly smaller than the hinge mechanism such that insertion of the hinge mechanism compacts material of the side knuckles116within the apertures117, thus causing pressure that holds the hinge mechanism in place. In another preferred embodiment, the hinge mechanism may be threaded, and the apertures117of certain side knuckles116may be larger than the hinge mechanism while the aperture117of other knuckles116may be threaded to interlock with the threads of the hinge mechanism. This may allow a worker805to adjust the height of the panels in relation to one another for application in which the ground is uneven. Other attachments and hinged mechanisms known in the art may also be utilized to create the hinges115without departing from the inventive subject matter herein. In one preferred embodiment, the front panel106, back panel107, first side panel108, and second side panel109may comprise an interior wall and an exterior wall. As illustrated inFIGS.1A-5, the exterior walls of the front panel106, back panel107, first side panel108, and second side panel109may comprise a plurality of compartments119, wherein said plurality of compartments119may hold dirt, concrete, asphalt, or some other material. This may prevent the base box105from being pulled out of the ground once installed on a site by allowing the base box105to “grip” the dirt, concrete, asphalt, etc. In a preferred embodiment, as illustrated in theFIGS.1A-5, the exterior wall may extend further away from the panels at the bottom end121of the base box105than at the top end128, creating a base box105having a flared bottom125. As illustrated, the base box105of the present invention comprises a flared bottom125having a flared interior space, thus providing additional interior room compared with straight-walled designs. This reduces the ground-mount surface area at the top end128while maximizing space towards the base end121of the base box105. This is particularly important for storing slack cable since the flared design would force slacked electrical cables and/or fiber optic cables to remain in the base of the base box once relaxed, which reduces the chance for said cables to be damaged. For instance, a coiled telecommunications cable and electrical cable operably connected to a switch may be coiled by a worker805and placed in the bottom of said base box105. The worker805may then allow the cables to relax and expand, thus preventing the cables from moving up through the narrower top of the base box105. This not only secures the cables inside but also protects them from damage. Because the flared wall bottoms are connected to a generally straight hinge, a preferred embodiment of the present invention allows for a non-linear configuration to hinge into a foldable system100. In another preferred embodiment, the hinges115may be secured in place via pins, screws, or other removable locking elements, which may allow a worker805to lock the base box105and/or extension box105in an open position or unlock the base box105and/or extension box105so that it may be folded. In one preferred embodiment, the plurality of compartments119on the exterior wall of the front panel106, back panel107, first side panel108, and second side panel109may extend further at the bottom end121of the base box105than the top end128, creating compartments that increase in volume when moving from the top end128to the bottom end121. The flared bottom125of the base box105prevents the box from being removed after installation by increasing the amount of surface area. Further, the flared bottom125allows dirt, concrete, asphalt, etc. to apply additional downward force to the front panel106, back panel107, first side panel108, and second side panel109, as illustrated inFIG.8, thus preventing removal after installation and/or vertical lift caused by environmental conditions. For instance, the flared bottom125may prevent frost heave from lifting the base box105out of the ground by increasing the amount of surface area of the base box105in contact with dirt as well as by increasing the downward force exerted on the base box by said dirt. In another preferred embodiment, as illustrated inFIGS.3and5, the front panel106, back panel107, first side panel108, and second side panel109of the base box105may comprise at least one opening130that allows pipes, wires, valves, etc. to extend in or out of said base box105. For instance, a base box105used to house telecommunications equipment may have a front panel106having an opening130so fiberoptic cable may enter the base box105to access a switchgear. This same base box105may further comprise a back panel107having an opening130so fiberoptic cable may exit the base box105to a telecommunications tower. For instance, a base box105used to house waterworks utilities may comprise a front panel106having an opening130so a supply pipe may provide water to a building from a mainline encapsulated within the base box105, wherein a meter housed within the base box105may measure the amount of water transferred from the mainline to the supply pipe. The openings130may be any shape so long as they allow pipes, wires, valves, etc. to extend into and out of the base box105. For instance, the opening130may comprise an arch so that the base box105may be placed around a pipe after the installation of said pipe. For instance, the opening130may comprise a small threaded hole which may then be fitted with a threaded gasket so that electrical wiring may be threaded through the gasket, which may prevent water from entering the base box105. Other connections and openings known in the art may also be utilized with the device and method FIGS.6and7illustrate top and bottom views of the device100, respectively. In one preferred embodiment, a lid135may be removably attached at the top end128of the base box105via the front panel106, back panel107, first side panel108, and second side panel109or the top end122of the extension box110via the front extension panel111, back extension panel112, first side extension panel113, and second side extension panel114. An inner ridge126at the top end128of the base box105and the top end122of the extension box110may provide a flanged area137for the lid135such that the lid135may securely sit on top of the device100. Alternatively, a hinge may rotatably attach the lid135to the top end of the device100. For instance, a plurality of knuckles116on the top end128of the front panel106may interlock with a plurality of knuckles116on the lid135, wherein a hinge mechanism inserted through an aperture117of the plurality of knuckles116may rotatably attach the lid135to the front panel106. In another preferred embodiment, the lid135may comprise a meter hole to allow for a worker805to check meter readings. The meter hole may be concealed by a meter tab, which may be rotatably secured to the lid135. In yet another preferred embodiment, a vent hole136may allow air to escape from the utility vault/enclosure when shut. The interior walls of the front panel106, back panel107, first side panel108, and second side panel109are preferably smooth. However, in other preferred embodiments, the interior walls may not be smooth, as illustrated inFIGS.6and7. For instance, the interior walls may comprise a plurality of hooks that may allow a worker805to string electrical wire within the cavity of the device100. For instance, the interior walls may be grooved in a way such if water condenses on the interior wall due to changes in temperature and/or humidity, the condensed water may be directed to an exit hole of the device100and away from any electronic equipment. In a preferred embodiment, the base box105is configured to receive an extension box110or lid135at a flanged area137of the top end128of the front panel106, back panel107, first side panel108, and second side panel109, as illustrated inFIG.6. The bottom end of the extension box110is configured to securely attach to the top end128of the base box105. In a preferred embodiment, the front panel106, back panel107, first side panel108, and second side panel109are configured such that an inner ridge126of the top end128is configured to accept the bottom end of an extension box110to sit within the base box105. A plurality of holes123of the top end128of the base box105and the bottom end of the extension box110may allow a worker805to secure the extension box110to the base box105. In a preferred embodiment, the extension box110is secured to the base box105via pins, screws, or other removable attachment elements. In another preferred embodiment, the top end128of the extension box110is also configured to receive a subsequent extension box110, which may be secured via the attachment elements. Adding additional extension boxes110will allow a worker805to create a utility vault as large as necessary. In another preferred embodiment, the exterior surfaces of the front extension panel111, back extension panel112, first side extension panel113, and second side extension panel114may comprise a plurality of compartments119, wherein said plurality of compartments119may hold dirt, concrete, asphalt, or some other material. This may allow the extension box110to “grip” dirt, concrete, asphalt, etc. in the same manner that the base box105might. Additionally, the inner surfaces of the of the front extension panel111, back extension panel112, first side extension panel113, and second side extension panel114may be smooth or otherwise, depending on the application. FIG.9provides a flow chart900illustrating certain, preferred method steps that may be used to carry out the process of installing a folding, flared utility vault. Step905indicates the beginning of the method. During step910, a worker805may install a public utility at a particular location. Once the worker805has installed the public utility, the worker805must obtain a base box105for the purpose of encasing a public utility installation during step915. In one preferred embodiment, the worker805may have to determine the specific base box105that must be used to encase the public utility installation. For instance, a worker805may have to determine whether to use a base box105designed for waterworks, telecommunications, or electrical before proceeding to the next step. Once the worker805has obtained the base box105, the worker805may encase the public utility with the base box105during step920. In some preferred embodiments, the worker805may have to insert or remove wires, pipes, fiberoptic cables, etc. through the openings130of the base box105prior to or after encasing the public utility with the base box105. Once encased, the worker805may determine whether an extension box110should be added to the base box105during step925. The worker805may take an action based on that determination during step930. If the worker805determines that no extension box110needs to be added to the base box105, the worker805may proceed to the terminate method step975. If the worker805determines that an extension box110does need to be added to the base box105, the worker805may obtain an extension box110during step935. Once the extension box110has been obtained, the worker805may attach the extension box110to the base box105during step940. The worker805may then proceed to step945, wherein the worker805may determine if a subsequent extension box110needs to be added to the previous extension box110. The worker805may take an action based on that determination during step950. If the worker805determines that no subsequent extension box110needs to be added to the previous extension box110, the worker805may proceed to the terminate method step975. If the worker805determines that a subsequent extension box110does need to be added to the previous extension box110, the worker805may obtain a subsequent extension box110during step955. Once the subsequent extension box110has been obtained, the worker805may attach the subsequent extension box110to the previous extension box110during step960. The worker805may then proceed to step965, wherein the worker805may determine if a subsequent extension box110needs to be added to the previously added extension box110. The worker805may take an action based on that determination during step970. If the worker805determines that an extension box110does need to be added to the base box105, the worker805may proceed to step955. If the worker805determines that no extension box110needs to be added to the base box105, the worker805may proceed to the terminate method step975. Although the systems and processes of the present disclosure have been discussed for use within the utility vault/enclosure field, one of skill in the art will appreciate that the inventive subject matter disclosed herein may be utilized in other fields or for other applications in which valves, pipes, wires, switchgears, etc. need to be encased. The implementations set forth in the foregoing description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations can be provided in addition to those set forth herein. For example, the implementations described above can be directed to various combinations and subcombinations of the disclosed features and/or combinations and subcombinations of several further features disclosed above. In addition, the logic flow depicted in the accompanying figures and/or described herein do not necessarily require the particular order shown, or sequential order, to achieve desirable results unless otherwise stated. It will be readily understood to those skilled in the art that various other changes in the details, materials, and arrangements of the parts and process stages which have been described and illustrated in order to explain the nature of this inventive subject matter can be made without departing from the principles and scope of the inventive subject matter. What is claimed is A base box comprising,a front panel having side knuckles,a back panel having said side knuckles,a pair of side panels having said side knuckles,wherein said side knuckles of said front panel, back panel, and pair of side panels interlock,wherein an exterior surface and an interior surface of at least one of said front panel, back panel, and pair of side panels flairs outward at said bottom end of said base box, wherein a hinge mechanism inserted into an aperture of said side knuckles rotatably attaches said front panel, back panel, and pair of side panels,wherein said front panel, back panel, and pair of side panels create an interior space when said side knuckles are rotatably attached,wherein a flanged area at a top end of said front panel, back panel, and pair of side panels allows for the attachment of an extension box. The system of claim1, wherein said exterior surface of at least one of said front panel, back panel, and pair of side panels comprise a plurality of compartments, The system of claim1, further comprising an opening in at least one of said back panel, front panel, and pair of side panels, wherein said opening grants utility lines additional access points and exit points to and from said interior space of said base box. The system of claims1, wherein said interior surface of at least one of said back panel, front panel, and pair of side panels further comprises a plurality of hooks. The system of claims1, wherein said interior surface of at least one of said back panel, front panel, and pair of side panels further comprises a plurality of grooves designed to direct liquid that condenses on said interior surface to an exit hole. The system of claim1, further comprising a lid configured to be secured within said flanged area at said top end of said front panel, back panel, and pair of side panels. The system of claim1, wherein said extension box comprises,a front extension panel having said side knuckles,a back extension panel having said side knuckles,a pair of side extension panels having said side knuckles,wherein said side knuckles of said front extension panel, back extension panel, and pair of side extension panels interlock,wherein said hinge mechanism inserted into said aperture of said side knuckles rotatably attaches said front extension panel, back extension panel, and pair of side extension panels,wherein said front extension panel, back extension panel, and pair of side extension panels create said interior space when said side knuckles are rotatably attached, wherein said front extension panel, back extension panel, and pair of side extension panels creates said flanged area at said top end and allows for the attachment of an additional extension box,wherein said bottom end of said front extension panel, back extension panel, and pair of side extension panels is configured to securely attach to said flanged area created by said back panel, front panel, and pair of side panels. The system of claim7, wherein said exterior surface of at least one of said front extension panel, back extension panel, and pair of side extension panels comprise a plurality of compartments. The system of claim7, wherein said exterior surface and said interior surface of at least one of said front extension panel, back extension panel, and side extension panels flairs outward at said bottom end. The system of claim9, wherein said interior surface of at least one of said front extension panel, back extension panel, and side extension panels further comprises a plurality of hooks. The system of claim9, wherein said interior surface of at least one of said front extension panel, back extension panel, and side extension panels further comprises a plurality of grooves designed to direct liquid that condenses on said interior surface to an exit hole. The system of claim7, further comprising an opening in at least one of said back extension panel, front extension panel, and pair of side extension panels, wherein said opening grants utility lines additional access points and exit points to and from said interior space of said extension box. The system of claim7, further comprising a lid configured to be secured within said flanged area at said top end of said front extension panel, back extension panel, and pair of side extension panels. An extension box comprising,a front extension panel having side knuckles,a back extension panel having said side knuckles,a pair of side extension panels having said side knuckles,wherein said side knuckles of said front extension panel, back extension panel, and pair of side extension panels interlock,wherein a hinge mechanism inserted into an aperture of said side knuckles rotatably attaches said front extension panel, back extension panel, and pair of side extension panels,wherein said front extension panel, back extension panel, and pair of side extension panels create an interior space when said side knuckles are rotatably attached,wherein a flanged area at a top end of said front extension panel, back extension panel, and pair of side extension panels allows for the attachment of an additional extension box,wherein a bottom end of said front extension panel, back extension panel, and pair of side extension panels is configured to securely attach to said flanged area. The system of claim14, wherein an exterior surface of at least one of said front extension panel, back extension panel, and pair of side extension panels comprises a plurality of compartments. The system of claim14, wherein an exterior surface and an interior surface of at least one of said front extension panel, back extension panel, and pair of side extension panels flairs outward at said bottom end of said extension box. The system of claims14, wherein an interior surface of at least one of said back extension panel, front extension panel, and pair of side extension panels further comprises a plurality of hooks. The system of claims14, wherein an interior surface of at least one of said back extension panel, front extension panel, and pair of side extension panels further comprises a plurality of grooves designed to direct liquid that condenses on said interior surface to an exit hole. The system of claim14, further comprising an opening in at least one of said back extension panel, front extension panel, and pair of side extension panels, wherein said opening grants utility lines additional access points and exit points to and from said interior space of said extension box. The system of claim14, further comprising a lid configured to be secured within said flanged area at said top end of said front extension panel, back extension panel, and pair of side extension panels. A utility vault comprising:a base box having a front panel, back panel, and pair of side panels,wherein an exterior surface and an interior surface of at least one of said front panel, back panel, and pair of side panels flairs outward at a bottom end,wherein said exterior surface of at least one of said front panel, back panel, and pair of side panels comprise a plurality of compartments wherein side knuckles of said front panel, back panel, and pair of side panels are configured in a way such that said front panel and said back panel interlock with said pair of side panels,wherein a hinge mechanism inserted into an aperture of said side knuckles rotatably attaches said front panel, back panel, and pair of side panels, andan extension box having a front extension panel, back extension panel, and pair of side extension panels,wherein said exterior surface and said interior surface of at least one of said front extension panel, back extension panel, and pair of side extension panels flairs outward at said bottom end,wherein said exterior surface of at least one of said front extension panel, back extension panel, and pair of side extension panels comprise said plurality of compartments wherein said side knuckles of said front extension panel, back extension panel, and pair of side extension panels are configured in a way such that said front extension panel and said back extension panel interlock with said pair of side extension panels,wherein said hinge mechanism inserted into said aperture of said side knuckles rotatably attaches said front extension panel, back extension panel, and pair of side extension panels,wherein said bottom end of said extension box is configured to securely attach to said top end of said base box. The system of claims21, wherein an interior surface of at least one of said front panel, back panel, pair of side panels, back extension panel, front extension panel, and pair of side extension panels further comprises a plurality of hooks. The system of claims21, wherein an interior surface of at least one of said front panel, back panel, pair of side panels, back extension panel, front extension panel, and pair of side extension panels further comprises a plurality of grooves designed to direct liquid that condenses on said interior surface to an exit hole. The system of claim21, further comprising an opening in at least one of said front panel, back panel, pair of side panels, back extension panel, front extension panel, and pair of side extension panels, wherein said opening grants utility lines additional access points and exit points to and from said interior space of said extension box. The system of claim21, further comprising a lid configured to be secured within a flanged area at said top end of said front extension panel, back extension panel, and pair of side extension panels. | 29,756 |
11862958 | DETAILED DESCRIPTION Electric power delivery systems are widely used to generate, transmit, and distribute electric power to loads, and serve as an important part of critical infrastructure. Power systems and components are often monitored and protected by intelligent electronic devices (IEDs) and systems of IEDs that obtain electric power system information from the equipment and monitor, automate, and provide protective actions for the power system. Several IEDs may be in communication to facilitate sharing of information for station-wide, area-wide, or even system-wide protection. For example, protection devices or relays may be IEDs that provide protection functions (e.g., detection and/or mitigation of faults or potential faults, such as overcurrent, differential, directional, distance, undervoltage, voltage regulation, bus protection, overfrequency, underfrequency, traveling wave, and/or other protection operations) to one or more portions of the electric power system. Stated in another way, a protection device or relay may be an IED that executes one or more operations to monitor and/or protect one or more portions of the electric power system and to decrease the likelihood of failure in the electric power system that may cause interruption of electric power and/or damage to the system or external objects proximate the electric power system. Due to the critical nature of electric power systems, protection and monitoring by the IEDs may assist in avoiding disruption of power systems. However, protection related functions in the IEDs may take up as little as 5 to 10% of computing resources (e.g., firmware), while non-protection functions take up relatively more, a majority of, or even all the remaining resources. Such non-protection functions may include, for example, supervisory control and data acquisition (SCADA) communications, other communications, event reporting, metering, diagnostics, and time management protocols. The firmware running on these IEDs has become complicated with the addition of non-protection related features in both hardware and/or firmware, such as, for example, communication protocols and automation features. These features can potentially affect the mission critical protection applications and can reduce the overall reliability of the device. It is generally accepted that the number of vulnerabilities, flaws, or bugs in computer code grows with the number of lines of code being implemented in a system. Estimates range from about 15 to 50 bugs per 1000 lines of code. With a monolithic (e.g., non-partitioned) firmware architecture, a bug in any part of the system may cause the entire system to fail. Thus, running code associated with functions unrelated to protection functions (e.g., event reporting, time management protocols, etc.) within an IED that is also running code for protection functions may render the protection functions provided by the IED less reliable due to the greater complexity and higher number of errors, which could result in misoperation of the device. Such errors may be vulnerabilities that could be exploited to gain unauthorized access to the IED, and such unauthorized access may be used to shut down portions of the electric power system through intentional or unintentional misoperation. Embodiments of the disclosure may provide solutions to this problem by providing IEDs with a full-featured operating system (e.g., Linux, Unix, QNX, VXWorks, etc.) that are capable of managing operation of software (e.g., firmware) executed in the IED by a processor. For example, on a system with a processor, the operating system may determine (e.g., prioritize) which function runs on the processor using one or more management features, such as, for example, a processor interrupt system, memory management unit, and partitioning of code into protection-enabling code and other code that handles other functions or control of the IED. In particular, embodiments of the disclosure may provide IEDs that are capable of prioritizing which function runs on the processor using one or more management features at startup or initialization of the IED (e.g., reset, booting, or otherwise preparing of the IED for operation). As discussed above, IEDs (e.g., relays) are becoming increasingly complex in both hardware and firmware. The increasing complexity is at least partially due to the wide area of protection, communication, and automation features in the IEDs. Initializing these features leads to a relatively longer startup time of the product. Longer startup times may lead to a delay in the enabling of protection in the IED that is provided to the electric power system (e.g., which protection features may be the main features of the IEDs). Such embodiments of the disclosure may provide IEDs that enable protection as fast as possible after powerup, and then bring up any other features, such as secondary features (e.g., communication and/or automation). Embodiments of the disclosure will enable the IEDs to enable protection faster while still providing the wide arrange of communication and automation features in such devices. Such embodiments may partition code relating to protection features from non-protection code (e.g., communication and/or automation code). Such partitioning may enable the IED to start the protection code initially, and once the protection code relating to the protection features is up and running, the IED will then start the other non-protection code (e.g., communication and automation code). In some embodiments, the IED may verify operation of one or more of the protective features before initiating any of the non-protective features. Embodiments of the disclosure may provide distinct and separate firmware images/applications where management of the firmware in the memory (e.g., via partitioning and/or one or more memory barriers) may provide quick startup for the protection features and may at least partially prevent protection firmware from being corrupted by the loading of other non-protective features. Such barriers and/or partitioning may enable protection to continue processing if the memory from the system firmware becomes corrupted during startup. Subsequently, the system firmware can be reset, restarted, and/or updated, while protection is still being run by the processor. Such a resetting, restarting, and/or updating of the non-protection functions may be accomplished without interrupting the protection functions. With certain functions (e.g., firmware related to protection functions) isolated from other functions (e.g., firmware related to non-protection functions) in such a system, the system may continue to operate even where there is an issue with the non-protection firmware. Such a system may continue to rely on the hundreds of thousands of lines of code that are necessary to run the complex operating system, even where the complexity associated with such large operating systems without otherwise compromising the protection functions. According to embodiments of the disclosure, IEDs (e.g., relays) may include architecture in which protection functions (i.e., those functions associated with operation of the electric power delivery system) are isolated from non-protection functions (i.e., those functions not associated with operation of the electric power delivery system). Such architecture may include a processing device along with memory management or protection. The memory may be partitioned into several applications (e.g., subsystems, executables, etc.) where the processing of each application (e.g., each firmware image) may be managed and where protection firmware may be isolated from non-protection functions. In some embodiments, the system memory may be partitioned at boot time and use a memory management unit (MMU), a memory protection unit, and/or memory barriers to prevent applications from accessing memory containing other applications' code and data. In accordance with some embodiments of the disclosure, protection functions may run in their own application, either with or without an operating system. For example, the protection function may operate in isolation from a majority or entirety of other functions or applications including the operating system. Such an application may primarily only perform protection functions. The code for the protection function applications may be made as relatively simple and small as possible (e.g., as compared with code for relatively more complex systems, such as an operating system, or an aggregate of code for multiple other functions and applications). Thus, in such a system with the ability to isolate the protection functions, the reliability of the protection functions may not be dependent on the quality of the code associated with features in the relays that are tasked with performing monitoring and protection functions. For example, in such a configuration, a fault occurring while running non-protection functions may cause that the firmware associated with those functions to be reset, restarted, updated, or otherwise remedied. However, the protection functions may remain substantially unaffected and continue to operate in a reliable manner. Accordingly, the power system supported by the protection functions may remain unaffected. In some embodiments, functions related to protection (e.g., diagnostic functions, alarm functions, etc.) may also be executed along with protection functions. In such embodiments, the code related to such functions may be limited to certain functions. Various embodiments consistent with the present disclosure may operate in connection with embedded systems. Embedded systems are designed to do a specific task (e.g., monitoring a portion of an electric power system). Embedded systems consistent with the present disclosure may be designed to provide high reliability and high security. In some embodiments, the protection elements may collectively or separately be partitioned in selected portions of the memory or on different, isolated portions of the memory where the protection functions are at least partially isolated from other functions performed by the processor. With such isolation of the protection functions, a particular protection element of the system may be initialized first and continue to provide uninterrupted protection to the electric power system, even while one or more other elements of the device experience an error and/or are reset. For example, a first protection function (e.g., a distance or impedance element) may be running on the processor, an overcurrent element may be running on the processor, and an underfrequency element (e.g., abnormal frequency) may be running on the processor. During unavailability of the second or third non-protection functions for any reason during startup or thereafter (e.g., firmware upgrade, computer failure, code error, firmware reset, etc.), the processor may continue to provide at least some of the protection for the electrical system (e.g., one or more transmission lines being monitored for impedance changes by the distance element). Modern electric power protection systems are integrated with automation, monitoring, and supervisory systems, all of which interact through digital communication. Embodiments of the present disclosure may provide relatively more reliable electric power protection system functions including automation, monitoring, and supervisory systems that effectively operate under normal operating conditions, where some of the functions (e.g., selected protection functions) to the power system may are prioritized over other non-protection functions. Such protection devices and systems may be segregated such that protection functions or operations take place in at least partial isolation (e.g., on common or segregated equipment) and do not rely on, or operate in unison with, other non-protection functions and/or general operating systems. In some embodiments, and as discussed above, the separation of such functions may be implemented within the same device at a processor level and/or a memory level. Such an approach may be also useful for scenarios where installing two or more separate devices may not be possible (e.g., due to physical space constraints, other constraints on overall system size, etc.). While protection functions are primarily discussed herein as being loaded separately from other functions, in additional embodiments, any desired first set of functions may be isolated from other functions in accordance with embodiments of the disclosure. The embodiments of the disclosure will be best understood by reference to the drawings. It will be readily understood that the components of the disclosed embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the systems and methods of the disclosure is not intended to limit the scope of the disclosure, as claimed, but is merely representative of possible embodiments of the disclosure. In addition, the steps of a method do not necessarily need to be executed in any specific order, or even sequentially, nor do the steps need to be executed only once, unless otherwise specified. In some cases, well-known features, structures, or operations are not shown or described in detail. Furthermore, the described features, structures, or operations may be combined in any suitable manner in one or more embodiments. It will also be readily understood that the components of the embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. For example, throughout this specification, any reference to “one embodiment,” “an embodiment,” or “the embodiment” means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification are not necessarily all referring to the same embodiment. Several aspects of the embodiments disclosed herein may be implemented as software modules or components. As used herein, a software module or component may include any type of computer instruction or computer executable code located within a memory device that is operable in conjunction with appropriate hardware to implement the programmed instructions. A software module or component may, for instance, comprise one or more physical or logical blocks of computer instructions, which may be organized as a routine, program, object, component, data structure, etc., that performs one or more tasks or implements particular abstract data types. In certain embodiments, a particular software module or component may comprise disparate instructions stored in different locations of a memory device, which together implement the described functionality of the module. Indeed, a module or component may comprise a single instruction or many instructions, and may be distributed over several different code segments, among different programs, and across several memory devices. Some embodiments may be practiced in a distributed computing environment where tasks are performed by a remote processing device linked through a communications network. In a distributed computing environment, software modules or components may be located in local and/or remote memory storage devices. In addition, data being tied or rendered together in a database record may be resident in the same memory device, or across several memory devices, and may be linked together in fields of a record in a database across a network. Embodiments may be provided as a computer program product including a non-transitory machine-readable medium having stored thereon instructions that may be used to program a computer or other electronic device to perform processes described herein. The non-transitory machine-readable medium may include, but is not limited to, hard drives, floppy diskettes, optical disks, CD-ROMs, DVD-ROMs, ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards, solid-state memory devices, or other types of media/machine-readable media suitable for storing electronic instructions. In some embodiments, the computer or another electronic device may include a processing device such as a microprocessor, microcontroller, logic circuitry, or the like. The processing device may further include one or more special-purpose processing devices such as an application specific interface circuit (ASIC), PAL, PLA, PLD, field programmable gate array (FPGA), or any other customizable or programmable device. Electrical power systems are designed to generate, transmit, and distribute electrical energy to loads. Electrical power systems may include equipment, such as electrical generators, electrical motors, power transformers, power transmission, and distribution lines, circuit breakers, switches, buses, transmission lines, voltage regulators, capacitor banks, and the like. Such equipment may be monitored, controlled, automated, and/or protected using intelligent electronic devices (IEDs) that receive electrical power system information from the equipment, make decisions based on the information, and provide monitoring, control, protection, and/or automation outputs to the equipment. In some embodiments, an IED may include, for example, remote terminal units, differential relays, distance relays, directional relays, feeder relays, overcurrent relays, voltage regulator controls, voltage relays, breaker failure relays, generator relays, motor relays, automation controllers, bay controllers, meters, recloser controls, communication processors, computing platforms, programmable logic controllers (PLCs), programmable automation controllers, input and output modules, governors, exciters, statcom controllers, static VAR compensator (SVC) controllers, on-load tap changer (OLTC) controllers, and the like. Further, in some embodiments, IEDs may be communicatively connected via a network that includes, for example, multiplexers, routers, hubs, gateways, firewalls, and/or switches to facilitate communications on the networks, each of which may also function as an IED. Networking and communication devices may also be integrated into an IED and/or be in communication with an IED. As used herein, an IED may include a single discrete IED or a system of multiple IEDs operating together. The electrical power system may be monitored, controlled, automated, and/or protected using intelligent electronic devices (IEDs). In general, IEDs in an electrical power system may be used for protection, control, automation, and/or monitoring of equipment in the system. For example, IEDs may be used to monitor equipment of many types, including electrical transmission lines, electrical distribution lines, current transformers, buses, switches, circuit breakers, reclosers, transformers, autotransformers, tap changers, voltage regulators, capacitor banks, generators, motors, pumps, compressors, valves, and a variety of other types of monitored equipment. In various embodiments, IEDs may be configured to monitor the frequency of alternating current waveforms, voltage levels, current levels (e.g., overcurrent and/or undercurrent), or other electrical conditions in the electrical power system. A network may be used to transmit information among various components in the electrical power system, including IEDs. In various embodiments, the network may be configured to provide streaming measurements that may be analyzed consistent with the present disclosure to detect anomalies. A common time signal may be used to time-align measurements for comparison and/or to synchronize action across the electrical power system. Utilizing a common or universal time source may ensure that IEDs have a synchronized time signal that can be used to generate time-synchronized data, such as synchrophasors. In various embodiments, the common time source may comprise a time signal from a global navigation satellite system (GNSS) system. An IED may include a receiver configured to receive the time signal from the GNSS system. In various embodiments, the IED may be configured to distribute the time signal to other components in the electrical power system, such as other IEDs. FIG.1illustrates a simplified one-line diagram of an electrical power delivery system100consistent with embodiments of the present disclosure. Electrical power delivery system100may be configured to generate, transmit, and distribute electrical energy to loads. Electrical power delivery systems may include equipment such as electrical generators (e.g., generators110,112,114, and116), power transformers (e.g., transformers117,120,122,130,142,144, and150), power transmission and delivery lines (e.g., lines124,134,136, and158), circuit breakers (e.g., breakers152,160,176), buses (e.g., buses118,126,132, and148), loads (e.g., loads140and138) and the like. In various embodiments, the electrical generators110,112,114, and116may comprise distributed generation sources (e.g., solar or wind generation). A variety of other types of equipment may also be included in electrical power delivery system100, such as voltage regulators, capacitor banks, and the like. Substation119may include a generator114, which may be a distributed generator, and which may be connected to bus126through step-up transformer117. Bus126may be connected to a distribution bus132via a step-down transformer130. Various distribution lines136and134may be connected to distribution bus132. Distribution line136may lead to substation141where the line136is monitored and/or controlled using IED106, which may selectively open and close breaker152. Load140may be fed from distribution line136. Further, step-down transformer144in communication with distribution bus132via distribution line136may be used to step down a voltage for consumption by load140. Distribution line134may lead to substation151, and deliver electrical power to bus148. Bus148may also receive electrical power from distributed generator116via transformer150. Distribution line158may deliver electrical power from bus148to load138, and may include further step-down transformer142. Circuit breaker160may be used to selectively connect bus148to distribution line134. IED108may be used to monitor and/or control circuit breaker160as well as distribution line158. Electrical power delivery system100may be monitored, controlled, automated, and/or protected using IEDs, such as IEDs104,106,108,115, and170, and a central monitoring system172. In general, IEDs in an electrical power generation and transmission system may be used for protection, control, automation, and/or monitoring of equipment in the system. For example, IEDs may be used to monitor equipment of many types, including electrical transmission lines, electrical distribution lines, current transformers, buses, switches, circuit breakers, reclosers, transformers, autotransformers, tap changers, voltage regulators, capacitor banks, generators, motors, pumps, compressors, valves, and a variety of other types of monitored equipment. An IED (such as IEDs104,106,108,115, and170) may refer to any microprocessor-based device that monitors, controls, automates, and/or protects monitored equipment within system100. Such devices may include, for example, remote terminal units, differential relays, distance relays, directional relays, feeder relays, overcurrent relays, voltage regulator controls, voltage relays, breaker failure relays, generator relays, motor relays, automation controllers, bay controllers, meters, recloser controls, communications processors, computing platforms, programmable logic controllers (PLCs), programmable automation controllers, input and output modules, and the like. The term IED may be used to describe an individual IED or a system comprising multiple IEDs. Central monitoring system172may comprise one or more of a variety of types of systems. For example, central monitoring system172may include a supervisory control and data acquisition (SCADA) system and/or a wide area control and situational awareness (WACSA) system. A central IED170may be in communication with IEDs104,106,108, and115. IEDs104,106,108, and115may be remote from the central IED170, and may communicate over various media such as a direct communication from IED106or over a wide-area communications network162. According to various embodiments, certain IEDs may be in direct communication with other IEDs (e.g., IED104is in direct communication with central IED170) or may be in communication via communication network162(e.g., IED108is in communication with central IED170via communication network162). As discussed above and in further detail below, one or more of the IEDs104,106,108,115, and170may be configured to separate and prioritize selected functions separately (e.g., via memory and/or processor management) such that the prioritized functions may be initialized first upon startup of the IEDs104,106,108,115, and170. For example, one or more functions (e.g., functions of relative higher priority, such as protection functions) may be segregated from one or more other functions (e.g., operating systems, communications, SCADA, etc.) in the memory of the IEDs104,106,108,115, and170. One or more of the protection functions (e.g., overcurrent, differential, directional, distance, undervoltage, voltage regulation, bus protection, overfrequency, underfrequency, traveling wave, and other protection operations) for one or more portions of the electric power system (e.g., the feeders, the buses, the transformers, etc.) may be stored and managed separately (e.g., stored separately in the memory of the respective IED and/or provided to the processor) from one or more other functions. Where more than one protection function is implemented, the protection functions may be stored and executed separately or as a group. A common time signal168may be used to time-align measurements for comparison and/or to synchronize actions across system100. Utilizing a common or universal time source may ensure that IEDs have a synchronized time signal that can be used to generate time-synchronized data, such as synchrophasors. In various embodiments, the common time source168may comprise a time signal from a GNSS system190. IED106may include a receiver192configured to receive the time signal from the GNSS system190. In various embodiments, IED106may be configured to distribute the time signal to other components in system100, such as IEDs104,108,115, and170. In various embodiments, wireless current sensors may be utilized in system100to measure electrical parameters in system100. Such measurements may be utilized by various control systems to implement control actions in system100. In one specific embodiment, wireless current sensors may be utilized in connection with distribution equipment, such as capacitor bank controls and other equipment that rely on phasor data for operation. Such systems may measure the degree to which the voltage of the power system is out of phase with the current of the system. Reactive power support may be provided by selectively connecting a capacitor bank174to system100using a breaker176. FIG.2illustrates a simplified representation of a system200for use in an electric power system to perform a plurality of functions consistent with embodiments of the present disclosure. System200includes a protection subsystem202, a reporting subsystem204, a SCADA subsystem206, and other functions208. As illustrated, each subsystem may include memory having one or more selected memory sections (e.g., partitioned memory sections226,228,230, and232) that may be in communication with a common CPU (e.g., processor210) and memory management features218. As depicted, the system200may include common memory management features218. In additional embodiments, the system200may include memory management features individually associated with each memory section226,228,230, and232. In some embodiments, the memory management features218may include one or more of a memory management unit (MMU), a processor interrupt system, and a partitioning of code. Selected code (e.g., firmware images) may be executed based on the current operational mode. For example, during unrestricted operation (e.g., after initialization of one or more protection functions at startup), the memory management features218(e.g., one or more MMUs) may enable or permit requests234to access any of the memory sections226,228,230, and232and enable the code from any of the memory sections226,228,230, and232to be executed by the processor210. However, during operations with at least some restriction (e.g., during startup prior to and/or during initialization of one or more protection functions), the memory management features218may restrict requests236to access one or more of the memory sections228,230, and232and/or restrict the code from one or more of the memory sections228,230, and232from being executed by the processor210. For example, in a restricted startup mode, only code from the protection subsystem202may be provided from the memory section226and that code may be accessed and executed by the processor210(e.g., initialized) while code from the other subsystems204,206, and208are prevented from being accessed and/or executed. By way of further example, in the restricted startup mode, code from the protection subsystem202may be prioritized over code from the other subsystems204,206, and208, thus increasing the protection system availability. The protection subsystem202may execute code stored on memory226using processor210. The operation of protection subsystem202may be independent of the other subsystems in system200and may be prioritized over other subsystems. For example, the isolated memory sections226,228,230, and232may allow each subsystem202,204,206, and208, to execute independently, where the code (e.g., firmware images) associated with each memory sections226,228,230, and232may be selectively executed and/or may be selectively terminated and/or prohibited from execution. Where implemented, a processor interrupt system of the memory management features218may cease the execution of at least some of the code (e.g., from the subsystems204,206, and208) and may direct the processor210to execute only the code from the protection subsystem202(e.g., for a selected period of time until the startup of the protection functions is completed, etc.). The subsystems illustrated inFIG.2may be embodied in a variety of ways in different embodiments. In one embodiment, system200may include physically distinct memory sections. In other embodiments, resources of a single system may be physically shared and logically separated (e.g., partitioned). For example, each memory section may be a portion of a larger memory array. FIG.3illustrates a simplified representation of an IED300for use in an electric power system and in which system resources are allocated to a plurality of functions consistent with embodiments of the present disclosure. IED300may perform one or more protection functions (e.g., a transformer protection relay, a bus protection relay, and/or a feeder protection relay). The IED300may be in communication with other IEDs (e.g., as depicted above inFIG.1) to receive power system information, for example, such as currents and/or voltages from the power system (e.g., from potential transformers (PT), current transformers (CT), etc.), along with communications, alerts, etc. As depicted, the IED300may include a processing subsystem316, a memory subsystem306, and a memory management subsystem326. In the processing subsystem316, processor318may execute tasks relating to the management and allocation of hardware, software resources, and provision of common services for other functions of the IED300(e.g., operational functions). Processor318may also provide protection functions relating to monitoring and/or controlling one or more aspects of the electrical power system, such as those discussed above. Processor318may further execute code that is not directly related to the protection functions, such as SCADA communications, communications between multiple IEDs, event reporting, and time management protocols (e.g., non-protection functions). Processor318may execute code related to event reporting. As discussed above, in one or more operational modes (e.g., a startup mode), the protection functions may be prioritized over the other functions (e.g., the non-protection and/or operational/control functions). For example, in a startup mode, only the protection functions may be provided (e.g., as firmware images) to the processor318such that the protection functions are initialized before any non-protection functions. After the protection functions are initialized (e.g., which may be a continuance of the startup mode or may be part of a different mode), non-protective functions may be provided to processor318only when the protection functions are determined to be operating within a selected range (e.g., determined to be adequately protecting the system). In some embodiments, execution of the non-protective functions by the processor318may be once again ceased if operation of the protection functions deviate from the selected respective ranges and are required to be started (e.g., in another startup process) and/or initialized again. The IED300may include system memory306that may be partitioned (e.g., at startup of the IED300) into sections allocated to a particular function or subsystem. In the illustrated embodiment, memory section 0308is associated with operational functions, memory section 1310is associated with protection functions, memory section 2312is associated with non-protection functions, and memory section 3314is associated with non-protection functions. The resources of the memory subsystem306may be permanently allocated to a particular function or may be allocated for a period of time and then reassigned or unassigned as necessary. The processing subsystem316may be a single processing device. A memory management subsystem326may manage access to the code (e.g., firmware images) stored in the memory subsystem306. For example, the memory management subsystem326may selectively grant or deny access to information stored in memory subsystem306to code executing on processing subsystem316. As above, the memory management subsystem326may include one or more of a memory management unit (MMU)328, a processor interrupt system330, memory partition and/or memory barrier features (e.g., the partitions or sections308,310,312, and314of memory subsystem326). During a restricted startup mode, memory management subsystem326(e.g., the memory management unit (MMU)328) may allow requests332for information stored in memory section 3314. Similarly, memory management subsystem326may allow a request334to access information stored in memory section 1310. However, memory management subsystem326may block request336to access information stored in memory section 0308under certain operational conditions (e.g., during startup). In some embodiments, the memory management subsystem326(e.g., the processor interrupt system330) may modify which code is executed by the processor316. For example, code being executed from memory section 0308and memory section 3314may be interrupted while code from memory section 1310may be prioritized to start execution or to continue execution by the processor318. As above, the memory management device326may comprise a single device, a plurality of devices for each subsystem, or combinations thereof. FIG.4illustrates a flow chart of a method400of operating a protection IED in an electric power system. At402, during a startup of the IED, on a processing unit of the IED, protection computing instructions may be implemented to at least one of monitor for or mitigate at least one fault in the electrical power system. In some embodiments, the processor may be embodied as processor210inFIG.2or processing subsystem316inFIG.3. Such systems may be used in an electric power system, such as the electric power system100illustrated inFIG.1. In various embodiments, the protection computing instructions may comprise an overcurrent protection function, a differential protection function, a directional protection function, a distance protection function, an undervoltage protection function, a voltage regulation protection function, a bus protection function, an overfrequency protection function, an underfrequency protection function, or a traveling wave protection function. At404, after implementing the protection computing instructions, on the processing unit, additional computing instructions may be implemented separately from the protection computing instructions. In various embodiments, the additional computing instructions may comprise supervisory control and data acquisition (SCADA) communications, communications between multiple IEDs, event reporting, metering, or time management protocols. The additional computing instructions may operate independently of the protection computing instructions, such that the additional computing instructions may be updated, reset, or suffer a fault or corruption without interrupting the protection computing instructions. The computer instructions (e.g., code, firmware, etc.) may be stored on a memory subsystem comprising a plurality of physically discrete memory elements. In other embodiments, a single computer-readable medium may comprise logical divisions corresponding to the first memory section and the second memory section. In various embodiments, the memory sections may be embodied as memory sections226-232inFIG.2or as memory sections 0-3308-314inFIG.3. At406, the additional computing instructions may be prohibited from being implemented on the processing unit while the protection computing instructions are being implemented. Such prohibiting may be facilitated by a memory management unit or subsystem, such as memory management units218-224inFIG.2or memory management subsystem326inFIG.3. While specific embodiments and applications of the disclosure have been illustrated and described, it is to be understood that the disclosure is not limited to the specific configurations and components disclosed herein. Accordingly, many changes may be made to the details of the above-described embodiments without departing from the underlying principles of this disclosure. The scope of the present invention should, therefore, be determined only by the following claims. | 38,824 |
11862959 | DETAILED DESCRIPTION The following description sets forth numerous specific details such as examples of specific systems, components, methods, and so forth, in order to provide a good understanding of various embodiments of the techniques described herein for recovering from short circuit conditions that may occur in USB-C/PD systems. It will be apparent to one skilled in the art, however, that at least some embodiments may be practiced without these specific details. In other instances, well-known components, elements, or methods are not described in detail or are presented in a simple block diagram format in order to avoid unnecessarily obscuring the techniques described herein. Thus, the specific details set forth hereinafter are merely examples. Particular implementations may vary from these example details and still be contemplated to be within the spirit and scope of the present invention. Reference in the description to “an embodiment,” “one embodiment,” “an example embodiment,” “some embodiments,” and “various embodiments” means that a particular feature, structure, step, operation, or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the invention. Further, the appearances of the phrases “an embodiment,” “one embodiment,” “an example embodiment,” “some embodiments,” and “various embodiments” in various places in the description do not necessarily all refer to the same embodiment(s). The description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show illustrations in accordance with exemplary embodiments. These embodiments, which may also be referred to herein as “examples,” are described in enough detail to enable those skilled in the art to practice the embodiments of the claimed subject matter described herein. The embodiments may be combined, other embodiments may be utilized, or structural, logical, and electrical changes may be made without departing from the scope and spirit of the claimed subject matter. It should be understood that the embodiments described herein are not intended to limit the scope of the subject matter but rather to enable one skilled in the art to practice, make, and/or use the subject matter. Described herein are various embodiments of techniques for recovering from short circuit conditions in USB-C/PD systems. The techniques allow for quicker and safer recovery for electronic devices from the short circuit conditions where a positive battery or power source terminal is electrically and/or physically exposed (e.g., in a car battery). Examples of such electronic devices include, without limitation, personal computers (e.g., laptop computers, notebook computers, etc.), mobile computing devices (e.g., tablets, tablet computers, e-reader devices, etc.), mobile communication devices (e.g., smartphones, cell phones, personal digital assistants, messaging devices, pocket PCs, etc.), connectivity and charging devices (e.g., hubs, docking stations, adapters, chargers, etc.), audio/video/data recording and/or playback devices (e.g., cameras, voice recorders, hand-held scanners, monitors, etc.), and other similar electronic devices that can use USB connectors (interfaces) (such as USB-C, USB-A, Micro-USB, and the like) for communication, battery charging, and/or power delivery. The embodiments described herein can be used for various types of power adapters, GaN based power adapters operating at 600 kHz frequencies, power adapters with primary or secondary side controllers, power adapters operating in modes of operations, such as quasi-resonant mode (QR), discontinuous conduction mode (DCM), continuous conduction mode (CCM), or the like. The embodiments described herein can be used in power-adapter solutions along with Type-C PD capability. Some embodiments of the present disclosure can enable USB-C/PD system to use existing circuits, components, mechanisms, etc., to recover from a short circuit condition, thereby reducing cost and complexity, while continuing to safely recover from the short circuit condition. For example, the USB-C/PD system may recover from a short circuit condition without causing transients for the power source (e.g., a car battery). These embodiments may work when both standard and non-standard USB-C cables are used. A USB-enabled electronic device or a system may comply with at least one release of a USB specification. Examples of such USB specifications include, without limitation, the USB Specification Revision 2.0, the USB 3.0 Specification, the USB 3.1 Specification, and/or various supplements (e.g., such as On-The-Go, or OTG), versions and errata thereof. The USB specifications generally define the characteristics (e.g., attributes, protocol definition, types of transactions, bus management, programming interfaces, etc.) of a differential serial bus that are required to design and build standard communication systems and peripherals. For example, a USB-enabled peripheral device attaches to a USB-enabled host device through a USB port of the host device to form a USB-enabled system. A USB 2.0 port includes a power voltage line of 5V (denoted VBUS), a differential pair of data lines (denoted D+ or DP, and D− or DN), and a ground line for power return (denoted GND). A USB 3.0 port also provides the VBUS, D+, D−, and GND lines for backward compatibility with USB 2.0. In addition, to support a faster differential bus (the USB SuperSpeed bus), a USB 3.0 port also provides a differential pair of transmitter data lines (denoted SSTX+ and SSTX−), a differential pair of receiver data lines (denoted SSRX+ and SSRX−), a power line for power (denoted DPWR), and a ground line for power return (denoted DGND). A USB 3.1 port provides the same lines as a USB 3.0 port for backward compatibility with USB 2.0 and USB 3.0 communications, but extends the performance of the SuperSpeed bus by a collection of features referred to as Enhanced SuperSpeed. A more recent technology for USB connectors, called USB Type-C, is defined in various releases and/or versions of the USB Type-C specification. The USB Type-C specification defines Type-C receptacle, Type-C plug, and Type-C cables that can support USB communications as well as power delivery over newer USB power delivery protocols defined in various revisions/versions of the USB-PD specification. Examples of USB Type-C functions and requirements may include, without limitation, data and other communications according to USB 2.0 and USB 3.0/3.1, electro-mechanical definitions and performance requirements for Type-C cables, electro-mechanical definitions and performance requirements for Type-C receptacles, electro-mechanical definitions and performance requirements for Type-C plugs, requirements for Type-C to legacy cable assemblies and adapters, requirements for Type-C-based device detection and interface configuration, requirements for optimized power delivery for Type-C connectors, etc. According to the USB Type-C specification(s), a Type-C port provides VBUS, D+, D−, GND, SSTX+, SSTX−, SSRX+, and SSRX− lines, among others. In addition, a Type-C port also provides a Sideband Use (denoted SBU) line for signaling of sideband functionality and a Configuration Channel (denoted CC) line for discovery, configuration, and management of connections across a Type-C cable. A Type-C port may be associated with a Type-C plug and/or a Type-C receptacle. For ease of use, the Type-C plug and the Type-C receptacle are designed as a reversible pair that operates regardless of the plug-to-receptacle orientation. Thus, a standard USB Type-C connector, disposed as a standard Type-C plug or receptacle, provides terminals for four VBUS lines, four ground return (GND) lines, two D+ lines (DP1 and DP2), two D− lines (DN1 and DN2), two SSTX+ lines (SSTXP1 and SSTXP2), two SSTX− lines (SSTXN1 and SSTXN2), two SSRX+ lines (SSRXP1 and SSRXP2), two SSRX− lines (SSRXN1 and SSRXN2), two configuration channel (CC) lines (e.g., CC1 and CC2), and two SBU lines (SBU1 and SBU2), among others. Some USB-enabled electronic devices may be compliant with a specific revision and/or version of the USB-PD specification. The USB-PD specification defines a standard protocol designed to enable the maximum functionality of USB-enabled devices by providing more flexible power delivery along with data communications over a single USB Type-C cable through USB Type-C ports. The USB-PD specification also describes the architecture, protocols, power supply behavior, parameters, and cabling necessary for managing power delivery over USB Type-C cables at up to 100 W of power. According to the USB-PD specification, devices with USB Type-C ports (e.g., such as USB-enabled devices) may negotiate for more current and/or higher or lower voltages over a USB Type-C cable than are allowed in older USB specifications (e.g., such as the USB 2.0 Specification, USB 3.1 Specification, the USB Battery Charging Specification Rev. 1.1/1.2, etc.). For example, the USB-PD specification defines the requirements for a power delivery contract (PD contract) that can be negotiated between a pair of USB-enabled devices. The PD contract can specify both the power level and the direction of power transfer that can be accommodated by both devices, and can be dynamically re-negotiated (e.g., without device un-plugging) upon request by either device and/or in response to various events and conditions, such as power role swap, data role swap, hard reset, failure of the power source, etc. According to the USB-PD specification, an electronic device is typically configured to deliver power to another device through a power path configured on a USB VBUS line. The device that provides power is typically referred to as (or includes) a “provider” (or a power source), and the device that consumes power is typically referred to as (or includes) a “consumer” (or a power sink). A power path typically includes a power switch coupled in-line on the VBUS line and configured to turn the delivery of power on and off. In one embodiment, a USB-PD power source can be configured to draw power from a direct current (DC) power source, and can include a direct current-to-direct current (DC-DC) converter. In other embodiments, a USB-PD power source may be configured to draw power from an alternating current (AC) power adapter or from another AC source. Thus, as part of an alternating current-to-direct current (AC-DC) conversion, some implementations may use a large bulk capacitor on the power source side of the VBUS line in order to remove the AC component of the power signal. Turn-ON and turn-OFF of power switches (also referred to as power FETs) may allow for further circuit protection based on analysis of current and voltage conditions and the detection of faults. In yet another embodiment, the USB-PD power source may be a battery, such as a car battery (e.g., a 12-volt battery used in automobiles and/or other vehicles). FIG.1is a block diagram of various multiport power adapters100configured to distribute power among ports according to one embodiment. The multiport power adapter100includes one master port102and one or more slave ports104. The master port102can be controlled by a master controller112. The slave ports104can be controlled by corresponding slave controllers114. Power converters108convert an input voltage to a different voltage. In the depicted embodiment, power converters108are DC-DC power converters. In one embodiment, the multiport power adapter100is a multiport USB-C automotive rear-seat charger of an automobile. In another embodiment, multiport power adapter100is part of a rear-seat entertainment system of an automobile. A rear-seat entertainment system can include a display system on chip (SoC), and one or more displays, or other power consuming devices, can be connected to the display SoC. In another embodiment, multiport power adapter100is part of a headunit of an automobile. The headunit of the automobile can include a USB hub and a power consuming device can be connected to the USB hub. Power consuming devices can consume power from the same power source as master port102and slave ports104, or power consuming devices can consume power from a different source. In the case where power consuming devices consume power from the same source as master port102and slave ports104, the multiport power adapter100allocate power between each of the master port102, the slave ports104, and the power consuming devices. In other embodiments, multiport power adapter100can be part of a multiport USB-C charger in a vehicle, car, truck, van, boat, plane, building, house, or the like. In other embodiments, multiport power adapter100is a multiport USB-C wall charger, a multiport USB-C power bank, a multiport USB-C power hub, a shared multiport power adapter, or the like. In other embodiments, multiport power adapter100may use ports other than USB-C ports, and is a multiport wall charger, a multiport power hub, a multiport power bank, or the like. In other embodiments, the multiport power adapter100may use ports other than USB-C, such as wall outlets, Micro-USB ports, or the like. In some embodiments, ports of the multiport USB-C power adapter100may not be all the same. For example, the multiport USB-C power adapter may include a number of USB Type-C ports and a number of other ports, such as USB-A, Micro-USB, and USB-A3.0ports. In USB-C/PD systems that are used in automobiles or automotive systems, the vehicle battery (e.g., a power source) may be exposed by a cigarette lighter socket or outlet. For example, a first end of a USB-C cable may fall into an exposed cigarette light outlet. Because the USB-C plug or connector body is the Type-C ground as well as system ground, there is a potential for short circuit when this occurs. Generally, the USB-C/PD system may disconnect the Type-C ground from system ground to prevent damage to the USB-C/PD system and/or the power source. When the Type-C ground is left floating, the USB-C/PD system may not be able to detect whether the short circuit condition is removed without periodically connecting the Type-C ground to system ground. This may cause transients for the power source (e.g., a car battery) and may increase the likelihood of damage to the power source or the USB-C/PD system. Though embodiments described herein relate may refer to short circuit conditions in automotive system or automobiles, the embodiments may be applicable in other conditions, situations, scenarios, systems, etc., where short circuit conditions may occur. For example, the techniques and systems described herein may be applied in aircraft, trains, etc. FIG.2is a diagram illustrating an example portion of a USB-C/PD system200according to one embodiment. The portion of the USB-C/PD system200includes a control circuit210and a ground line220. In one embodiment, the portion of the USB-C/PD system200may be included in a vehicle, such as an automobile or car. For example, the portion of the USB-C/PD system200may be a USB-C automotive charger that is coupled to a USB-C port/connect in the automobile.FIG.2illustrates how existing USB Type-C signals (USB Type-C GND) may be connected to a control circuit210for short circuit recovery. The control circuit210is coupled to the ground line220. The ground line220is coupled to a system ground and a connector225via a resistor222and a ground isolation switch221. The ground isolation switch221may be a field effect transistor (FET), a metal-oxide semiconductor FET (MOSFET), etc. The connector225may be a USB-C connector, which may also include a Type-C ground, as discussed above. The control circuit210includes a current sense amplifier (CSA)211that is coupled to the ground line220before and after the resistor222. The control circuit further includes a control logic219, a driver212, a comparison circuit214, a switch213, and a resistor RINT. The control circuit210may also be coupled one or more voltage sources (not illustrated inFIG.2). The one or more voltage sources may generate a reference voltage VREFthat may be used by the comparison circuit214. The driver212(e.g., a gate driver) may be coupled to a gate of the ground isolation switch221. The driver212may generate, output, provide, etc., a voltage VGto the gate of the ground isolation switch221. In one embodiment, if a first voltage (e.g., a high voltage, a first VG, etc.) is provided to the gate of the ground isolation switch221, the ground isolation switch221may be turned on and a current may be allowed to flow through the ground isolation switch221. The first voltage may be referred to as an activation voltage because driving the gate of the ground isolation switch221to the first voltage may result in turning on the ground isolation switch221. In another embodiment, if a second voltage (e.g., a low voltage, a second VG, etc.) is provided to the gate of the ground isolation switch221, the ground isolation switch221may be turned off and a current may not be allowed to flow through the ground isolation switch221. The second voltage may be referred to as a shut-off voltage because driving the gate of the isolation switch221to the second voltage may result in turning off the ground isolation switch221. In one embodiment, the control circuit210may determine whether a short circuit condition has occurred. For example, the CSA211may determine whether the voltage detected across resistor222on the ground line220is greater than an overvoltage threshold (e.g., a threshold, a first threshold voltage, a voltage level, etc.). If the voltage detected across resistor222on the ground line220is greater than the overvoltage threshold, this may indicate that a short circuit condition has occurred. The CSA211may transmit a signal, data, etc., to the control logic219to indicate that the voltage detected across resistor222on the ground line220is greater than the overvoltage threshold (e.g., to indicate that the short circuit condition has occurred causing a high current to flow through ground line220). In one embodiment, the control circuit210may turn off the ground isolation switch221(e.g., a field effect transistor (FET)) when a short circuit condition has occurred. The control circuit210may control the gate of the ground isolation switch221to turn off the ground isolation switch221and to prevent current from flowing between the system ground (e.g., the ground for the power source of the USB-C/PD system200, such as a 12V car battery, a power outlet, etc.) and the USB-C ground (e.g., Type-C ground) if a short circuit condition occurs. For example, when the control logic219receives a signal from the CSA211indicating that the short circuit condition has occurred, the control logic219may cause or instruct the driver212to generate or provide a second voltage (e.g., a low voltage) to the gate of the ground isolate switch221. This may turn off the ground isolation switch221and a current may not be allowed to flow through the ground isolation switch221(e.g., current may not flow from the Type-C ground to the system ground). When the ground isolation switch221is turned off, this may decouple the connection between the system ground and the USB-C ground via the ground isolation switch221(e.g., may disconnect the connection between the system ground, the ground isolation switch221, and the USB-C ground). The control circuit210may allow the USB-C/PD system (e.g., another controller, another control circuit, etc., that may include the control circuit210) to determine that a short circuit condition is no longer present or occurring. In one embodiment, the control circuit210may float the ground isolation switch221. For example, the output of the ground isolation switch221may be floated. The control logic219may float the ground isolation switch221by causing or instructing the driver212to turn off such that the driver212does not provide a voltage to the gate of the ground isolation switch221. Floating the ground isolation switch221may allow the current to flow from the connector225, through the resistor REXT, and through the resistor RINTto a ground. REXTmay be referred to as an external resistor because REXTmay be separate or external to control circuit210. RINTmay be referred to as an internal resistor because RINTis part of or internal to control circuit210. In one embodiment, the control circuit210may determine whether a short circuit condition is no longer present or occurring based on VREF(e.g., a second threshold voltage). For example, the control logic219may configure, toggle, activate, etc., switch213which may couple one input of the comparison circuit214(e.g., the left input) to a resistor RINT(which in turn is coupled to a ground). By coupling the input of the comparison circuit214to the resistor RINT, the control circuit210may provide a path for the current from the connector225to flow through to a ground. For example, the current may flow from the connector225, through the resistor REXT, and through the resistor RINTto a ground. The control circuit210may use the comparison circuit214to determine whether the voltage on the ground line220less than the voltage VREF. For example, comparison circuit214(e.g., a comparator) may determine whether the voltage detected at the first input (e.g., from the current flowing through resistors REXTand RINT) is less than the voltage VREF. The control circuit210may periodically monitor the output of the comparison circuit214. In another example, the control circuit210may receive an interrupt, signal, data, etc., from the comparison circuit214when the voltage on the ground line220goes low (with removal of short between type-C ground and battery voltage) such that, the resistive divided signal VG(of two resistors REXTand RINT) is less than the voltage VREF. In one embodiment, the control circuit210may turn on the ground isolation switch221in response to determining that the voltage on the ground line220is low enough to cause VGto become lower (e.g., less than) than the voltage VREF(e.g., the second threshold voltage). The control circuit210may control the gate to allow current to flow between the system ground and the USB-C ground. For example, the control logic219may cause or instruct the driver212to provide the first voltage (e.g., a high voltage, an activation voltage, etc.) to the gate of the ground isolation switch221. When the ground isolation switch221is turned on, this may couple the system ground and the USB-C ground via the ground isolation switch221(e.g., may establish a connection between the system ground, the ground isolation switch221, and the USB-C ground). The control circuit210may turn the ground isolation switch221back on because the control circuit210may determine that the short circuit condition is no longer occurring or no longer present. If the voltage on the ground line220decreases to a voltage low enough to cause VGto be less than VREF(e.g., the second threshold voltage), this indicates that the short circuit condition is no longer occurring. For example, a user may remove a first end of the USB-C cable from an exposed cigarette lighter outlet (e.g., an automobile auxiliary power outlet) which may stop the short circuit from occurring. This may indicate to the control circuit210that the ground isolation switch221may be turned on (e.g., current is allowed to flow from the connector225through the ground isolation switch221). In one embodiment, the control circuit210may also configure, toggle, deactivate, etc., switch213to decouple the comparison circuit214(e.g., the left input) from the resistor RINT(e.g., may disconnect the switch213). This may allow the current from the connector225to flow through the ground line220to the system ground, rather than flowing through the resistor RINT. In one embodiment, the control circuit210may perform or initiate one or more error recovery operations after turning on the ground isolation switch221. For example, the control circuit210may initiate USB Type-C error recovery operations. In another example, the control circuit210may initiate a restart or reboot of one or more processing devices/units in the USB-C/PD system200(e.g., may reboot a USB-C/PD controller). In a further example, the control circuit210may erase or reinitialize a memory device (e.g., flash memory) of the USB-C/PD system200. In a further example, the control circuit210may begin communicating data with a USB-enabled device that is coupled to the USB-C/PD system200(e.g., may begin to negotiate power delivery requirements with the device). In one embodiment, the control circuit210may be able to utilize or take advantage of the leaky nature of the control circuit210to determine that the short circuit condition has ended or been removed. As discussed above, when the short circuit condition has ended or been removed (e.g., cable end is removed from a cigarette lighter outlet, cable end is unplugged, etc.) remaining current from the short circuit condition may flow through the resistors REXTand RINTto ground (e.g., may discharge to ground). This allows the control circuit210to determine that the short circuit condition has ended or been removed. In one embodiment, the control circuit210may reduce or minimize transients (e.g., transient conditions) on the power source for the USB-C/PD system200. For example, rather periodically turning on the ground isolation switch221to see if the short circuit condition has ended (which may cause a high voltage to pass through to the power source), the control circuit may determine that the short circuit condition has ended or stopped before turning on the ground isolation switch221. FIG.3is a flow diagram of a method300of recovering from a short circuit in a USB-C/PD system according to one embodiment. The method300may be performed by processing logic that comprises hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software, firmware, or a combination thereof. In one embodiment, the method300may be performed by any of the processing devices described herein. In one embodiment, the method300is performed by processing logic (or a controller) in the USB-C/PD system, such as USB-C controller400illustrated inFIG.4or control circuit210illustrated inFIG.2. In one embodiment, a control circuit (e.g., controller) may execute a firmware-based method that performs the following operations. In another embodiment, an integrated circuit (IC) controller may have embedded code or logic and is configured to execute instructions to perform the following operations. Referring back toFIG.3, the method300begins at block305where the processing logic may determine whether there is a short circuit condition. For example, the processing logic may use a current sense amplifier to determine whether the voltage on a ground line of the USB-C/PD system is greater than an overvoltage threshold. If there is a short circuit condition, the processing logic may turn off a ground isolation switch at block310. For example, the processing logic may control a gate of the ground isolation switch accordingly (e.g., may drive the gate to a shut-off voltage to turn off the ground isolation switch). If there is no short circuit condition, the processing logic may continue to check for short circuit conditions at block305. At block315, the processing logic may couple the gate node to an internal resistor. For example, referring toFIG.2, the processing logic may connect, close, couple, etc., the switch213to couple the resistor RINTto the gate node of the ground isolation switch221. As discussed above, this may allow a current to flow from the connector225, through the resistor REXT, and through the resistor RINTto a ground. At block320, the processing logic may float the ground isolation switch. For example, the processing logic may not apply a voltage to the gate of the ground isolation switch. At block325, the processing logic may determine whether a voltage detected by a comparison circuit (e.g., comparison circuit214illustrated inFIG.2) is less than a threshold voltage (e.g., VREF). If the voltage (detected by the comparison circuit) is not less than the threshold voltage, this may indicate that a short circuit condition is still occurring and the processing logic may continue determining whether the voltage is less than the threshold voltage at block325. If the voltage (detected by the comparison circuit) is less than the threshold voltage, this may indicate that a short circuit condition is no longer occurring (e.g., the short circuit has been removed), and the processing logic may turn on the ground isolation switch at block330. For example, the processing logic may control the gate of the ground isolation switch accordingly (e.g., may drive the gate to an activation voltage to turn on the ground isolation switch). At block340, the processing logic may perform or initiate one or more error recovery operations. For example, the processing logic may reboot one or more processing devices, reset a memory device, etc. FIG.4is a block diagram illustrating an architecture400for a USB device for use in USB power delivery in accordance with some embodiments. In some embodiments, system400may be an integrated circuit (IC) controller. The architecture400may include a peripheral subsystem410including a number of components for use in USB Power Delivery (USB-PD). Peripheral subsystem410may include a peripheral interconnect411including a clocking module, peripheral clock (PCLK)412for providing clock signals to the various components of peripheral subsystem410. Peripheral interconnect411may be a peripheral bus, such as a single-level or multi-level advanced high-performance bus (AHB), and may provide a data and control interface between peripheral subsystem410, CPU subsystem430, and system resources440. Peripheral interconnect411may include control circuits, such as direct memory access (DMA) controllers, which may be programmed to transfer data between peripheral blocks without input by, control of, or burden on CPU subsystem430. The peripheral interconnect411may be used to couple components of peripheral subsystem410to other components of architecture400. Coupled to peripheral interconnect411may be a number of general purpose input/outputs (GPIOs)415for sending and receiving signals. GPIOs415may include circuits configured to implement various functions such as pull-up, pull-down, input threshold select, input and output buffer enabling/disable, single multiplexing, etc. Still other functions may be implemented by GPIOs415. One or more timer/counter/pulse-width modulator (TCPWM)417may also be coupled to the peripheral interconnect and include circuitry for implementing timing circuits (timers), counters, pulse-width modulators (PWMs) decoders, and other digital functions that may operate on I/O signals and provide digital signals to system components of architecture400. Peripheral subsystem410may also include one or more serial communication blocks (SCBs)419for implementation of serial communication interfaces such as I2C, serial peripheral interface (SPI), universal asynchronous receiver/transmitter (UART), controller area network (CAN), clock extension peripheral interface (CXPI), etc. For USB power delivery applications, peripheral subsystem410may include a USB power delivery subsystem420coupled to the peripheral interconnect and comprising a set of USB-PD modules421for use in USB power delivery. USB-PD modules421may be coupled to the peripheral interconnect411through a USB-PD interconnect423. USB-PD modules421may include an analog-to-digital conversion (ADC) module for converting various analog signals to digital signals; an error amplifier (AMP) regulating the output voltage on VBUS line per a PD contract; a high-voltage (HV) regulator for converting the power source voltage to a precise voltage (such as 3.5-5V) to architecture400; a low-side current sense amplifier (LSCSA) for measuring load current accurately, an over voltage protection (OVP) module and an over-current protection (OCP) module for providing over-current and over-voltage protection on the VBUS line with configurable thresholds and response times; one or more gate drivers for external power field effect transistors (FETs) used in USB power delivery in provider and consumer configurations; and a communication channel PHY (CC BB PHY) module for supporting communications on a Type-C communication channel (CC) line. USB-PD modules421may also include a charger detection module for determining that a charging circuit is present and coupled to architecture400and a VBUS discharge module for controlling discharge of voltage on VBUS. The discharge control module may be configured to couple to a power source node on the VBUS line or to an output (power sink) node on the VBUS line and to discharge the voltage on the VBUS line to the desired voltage level (i.e., the voltage level negotiated in the PD contract). USB power delivery subsystem420may also include pads427for external connections and electrostatic discharge (ESD) protection circuitry429, which may be required on a Type-C port. USB-PD modules421may also include a bi-directional communication module for supporting bi-directional communications with another controller, such as between a primary-side controller and a secondary-side controller of a flyback converter. In one embodiment, the control circuit210illustrated inFIG.2may be part of the USB power delivery subsystem420and/or part of the USB-PD modules421. For example, the control circuit may be part of the OVP module. GPIO415, TCPWM417, and SCB419may be coupled to an input/output (I/O) subsystem450, which may include a high-speed (HS) I/O matrix451coupled to a number of GPIOs453. GPIOs415, TCPWM417, and SCB419may be coupled to GPIOs453through HS I/O matrix451. Architecture400may also include a central processing unit (CPU) subsystem430for processing commands, storing program information, and data. CPU subsystem430may include one or more processing units431for executing instructions and reading from and writing to memory locations from a number of memories. Processing unit431may be a processor suitable for operation in an integrated circuit (IC) or a system-on-chip (SOC) device. In some embodiments, processing unit431may be optimized for low-power operation with extensive clock gating. In this embodiment, various internal control circuits may be implemented for processing unit operation in various power states. For example, processing unit431may include a wake-up interrupt controller (WIC) configured to wake the processing unit up from a sleep state, allowing power to be switched off when the IC or SOC is in a sleep state. CPU subsystem430may include one or more memories, including a flash memory433, and static random access memory (SRAM)435, and a read-only memory (ROM)437. Flash memory433may be a non-volatile memory (NAND flash, NOR flash, etc.) configured for storing data, programs, and/or other firmware instructions. Flash memory433may include a read accelerator and may improve access times by integration within CPU subsystem430. SRAM435may be a volatile memory configured for storing data and firmware instructions accessible by processing unit431. ROM437may be configured to store boot-up routines, configuration parameters, and other firmware parameters and settings that do not change during operation of architecture400. SRAM435and ROM437may have associated control circuits. Processing unit431and the memories may be coupled to a system interconnect439to route signals to and from the various components of CPU subsystem430to other blocks or modules of architecture400. System interconnect439may be implemented as a system bus such as a single-level or multi-level AHB. System interconnect439may be configured as an interface to couple the various components of CPU subsystem430to each other. System interconnect439may be coupled to peripheral interconnect411to provide signal paths between the components of CPU subsystem430and peripheral subsystem410. Architecture400may also include a number of system resources440, including a power module441, a clock module443, a reset module445, and a test module447. Power module441may include a sleep control module, a wake-up interrupt control (WIC) module, a power-on-reset (POR) module, a number of voltage references (REF), and a PWRSYS module. In some embodiments, power module441may include circuits that allow architecture400to draw and/or provide power from/to external sources at different voltage and/or current levels and to support controller operation in different power states, such as active, low-power, or sleep. In various embodiments, more power states may be implemented as architecture400throttles back operation to achieve a desired power consumption or output. Clock module443may include a clock control module, a watchdog timer (WDT), an internal low-speed oscillator (ILO), and an internal main oscillator (IMO). Reset module445may include a reset control module and an external reset (XRES) module. Test module447may include a module to control and enter a test mode as well as testing control modules for analog and digital functions (digital test and analog DFT). Architecture400may be implemented in a monolithic (e.g., single) semiconductor die. In other embodiments, various portions or modules of architecture400may in implemented on different semiconductor dies. For example, memory modules of CPU subsystem430may be on-chip or separate. In still other embodiments, separate-die circuits may be packaged into a single multi-chip module, or remain separate and disposed on a circuit board (or in a USB cable connector) as separate elements. Architecture400may be implemented in a number of application contexts to provide USB-PD functionality thereto. In each application context, an IC controller or SOC implementing architecture400may be disposed and configured in an electronic device (e.g., a USB-enabled device) to perform operations in accordance with the techniques described herein. In one example embodiment, an architecture400may be disposed and configured in a vehicle (e.g., a car, truck, automobile, etc.), etc. In another example embodiment, architecture400may be disposed and configured in a power adapter (e.g., a wall charger) for a mobile electronic device (e.g., a smartphone, a tablet, etc.). In another example embodiment, architecture400may be disposed and configured in a wall socket that is configured to provide power over USB Type-A and/or Type-C port(s). In another example embodiment, architecture400may be disposed and configured in a car charger that is configured to provide power over USB Type-A and/or Type-C port(s). In yet another example embodiment, architecture400may be disposed and configured in a power bank that can get charged and then provide power to another electronic device over a USB Type-A or Type-C port. In other embodiments, a system like architecture400may be configured with the power switch gate control circuitry described herein and may be disposed in various other USB-enabled electronic or electro-mechanical devices. It should be understood that an architecture, like architecture400implemented on or as an IC controller may be disposed into different applications, which may differ with respect to the type of power source being used and the direction in which power is being delivered. For example, in the case of a car charger, the power source is a car battery that provides DC power, while in the case of a mobile power adapter the power source is an AC wall socket. Further, in the case of a PC power adapter the flow of power delivery is from a provider device to consumer device, while in the case of a power bank the flow of power delivery may be in both directions depending on whether the power bank is operating as a power provider (e.g., to power another device) or as a power consumer (e.g., to get charged itself). For these reasons, the various applications of architecture400should be regarded in an illustrative rather than a restrictive sense. In the above description, some portions of the detailed description are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as “determining”, “turning,” “turning on,” “turning off,” “configuring,” “reconfiguring,” “charging,” “performing,” or the like, refer to the actions and processes of a computing system, or similar electronic computing device, that manipulates and transforms data represented as physical (e.g., electronic) quantities within the computing system's registers and memories into other data similarly represented as physical quantities within the computing system memories or registers or other such information storage, transmission or display devices. The words “example” or “exemplary” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “example’ or “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words “example” or “exemplary” is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X includes A or B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Moreover, use of the term “an embodiment” or “one embodiment” or “an embodiment” or “one embodiment” throughout is not intended to mean the same embodiment or embodiment unless described as such. Embodiments descried herein may also relate to an apparatus for performing the operations herein. This apparatus may be activated or reconfigured by stored firmware instructions. Such firmware instructions may be stored in a non-transitory computer-readable storage medium, such as, but not limited to, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, flash memory, or any type of media suitable for storing electronic instructions on a IC chip. The term “computer-readable medium” shall also be taken to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the machine and that causes the machine to perform any one or more of the methodologies of the present embodiments. The term “computer-readable storage medium” shall accordingly be taken to include, but not be limited to, solid-state memories, magnetic media, any medium that is capable of storing a set of instructions for execution by the machine and that causes the machine to perform any one or more of the methodologies of the present embodiments. The above description sets forth numerous specific details such as examples of specific systems, components, methods, and so forth, in order to provide a good understanding of several embodiments of the present disclosure. It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. | 44,991 |
11862960 | DETAILED DESCRIPTION The following disclosure provides different embodiments, or examples, for implementing features of the provided subject matter. Specific examples of components, materials, values, steps, arrangements, or the like, are described below to simplify the present disclosure. These are, of course, merely examples and are not limiting. Other components, materials, values, steps, arrangements, or the like, are contemplated. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. In some embodiments, an ESD protection circuit includes a first diode, a second diode and an ESD clamp circuit. The first diode is in a semiconductor wafer, and is coupled to an input output (IO) pad. The second diode is in the semiconductor wafer, and is coupled to the first diode and the IO pad. The ESD clamp circuit is in the semiconductor wafer, and is coupled to the first diode and the second diode. The ESD clamp circuit includes a first signal tap region and a second signal tap region in the semiconductor wafer. The first signal tap region is coupled to a first voltage supply. The second signal tap region is coupled to a second voltage supply different from the first voltage supply. The first diode is coupled to and configured to share the first signal tap region with the ESD clamp circuit. The second diode is coupled to and configured to share the second signal tap region with the ESD clamp circuit. In some embodiments, by the first diode sharing the first signal tap region with the ESD clamp circuit, and by the second diode sharing the second signal tap region with the ESD clamp circuit, the ESD protection circuit of the present disclosure occupies less area than other approaches. In some embodiments, by the first diode sharing the first signal tap region with the ESD clamp circuit, and by the second diode sharing the second signal tap region with the ESD clamp circuit, the ESD protection circuit of the present disclosure has less signal taps than other approaches resulting in the ESD protection circuit of the present disclosure having less resistance than other approaches. In some embodiments, by having less resistance than other approaches, the ESD protection circuit of the present disclosure has a lower clamping voltage and is faster in operation than other approaches. FIG.1is a schematic block diagram of an integrated circuit100, in accordance with some embodiments. Integrated circuit100comprises an internal circuit102, a voltage supply node104, a reference voltage supply node106, an input/output (IO) pad108, a diode D1, a diode D2, an10circuit110and an ESD clamp circuit120. In some embodiments, at least integrated circuit100,200(FIG.2) or300A-300B (FIGS.3A-3B) is incorporated on a single integrated circuit (IC), or on a single semiconductor substrate. In some embodiments, at least integrated circuit100,200(FIG.2) or300A-300B (FIGS.3A-3B) includes one or more ICs incorporated on one or more single semiconductor substrates. Internal circuit102is coupled to the IO circuit110. In some embodiments, internal circuit102is further coupled to IO pad108, diode D1and diode D2. Internal circuit102is configured to receive an IO signal from IO pad108through IO circuit110. In some embodiments, internal circuit102is coupled to voltage supply node104(e.g. VDD) and reference voltage supply node106(e.g., VSS). In some embodiments, internal circuit102is configured to receive a supply voltage VDD from voltage supply node104(e.g. VDD), and a reference supply voltage VSS from reference voltage supply node106(e.g., VSS). Internal circuit102includes circuitry configured to generate or process the IO signal received by or output to IO pad108. In some embodiments, internal circuit102comprises core circuitry configured to operate at a voltage lower than supply voltage VDD of voltage supply node104. In some embodiments, internal circuit102includes at least one n-type or p-type transistor device. In some embodiments, internal circuit102includes at least a logic gate cell. In some embodiments, a logic gate cell includes an AND, OR, NAND, NOR, XOR, INV, AND-OR-Invert (AOI), OR-AND-Invert (OAI), MUX, Flip-flop, BUFF, Latch, delay, or clock cells. In some embodiments, internal circuit102includes at least a memory cell. In some embodiments, the memory cell includes a static random access memory (SRAM), a dynamic RAM (DRAM), a resistive RAM (RRAM), a magnetoresistive RAM (MRAM) or read only memory (ROM). In some embodiments, internal circuit102includes one or more active or passive elements. Examples of active elements include, but are not limited to, transistors and diodes. Examples of transistors include, but are not limited to, metal oxide semiconductor field effect transistors (MOSFET), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJT), high voltage transistors, high frequency transistors, p-channel and/or n-channel field effect transistors (PFETs/NFETs), FinFETs, and planar MOS transistors with raised source/drain. Examples of passive elements include, but are not limited to, capacitors, inductors, fuses, and resistors. Voltage supply node104is coupled to diode D1and ESD clamp circuit120at node Nd1. Reference voltage supply node106is coupled to diode D2and ESD clamp circuit120at node Nd2. Voltage supply node104is configured to receive supply voltage VDD for normal operation of internal circuit102. Similarly, reference voltage supply node106is configured to receive reference supply voltage VSS for normal operation of internal circuit102. In some embodiments, at least voltage supply node104is a voltage supply pad. In some embodiments, at least reference voltage supply node106is a reference voltage supply pad. In some embodiments, a pad is at least a conductive surface, a pin, a node or a bus. Voltage supply node104or reference voltage supply node106is also referred to as a power supply voltage bus or rail. In the example configuration inFIG.1,2or3A-3B, supply voltage VDD is a positive supply voltage, voltage supply node104is a positive power supply voltage, reference supply voltage VSS is a ground supply voltage, and reference voltage supply node106is a ground voltage terminal. Other power supply arrangements are within the scope of the present disclosure. IO pad108is coupled to IO circuit110by a node Nd3. IO pad108is coupled to internal circuit102by IO circuit110. In some embodiments, IO circuit110is not included in integrated circuit100, and IO pad is coupled to internal circuit102directly. IO pad108is configured to receive IO signal from IO circuit110or configured to output IO signal to IO circuit110. IO pad108is at least a pin that is coupled to IO circuit110or internal circuit102. In some embodiments, IO pad108is a node, a bus or a conductive surface that is coupled to IO circuit110or internal circuit102. Diode D1is coupled between voltage supply node104and IO pad108. Diode D1is coupled between node Nd1and node Nd3. An anode of diode D1is coupled to node Nd3, IO circuit110, IO pad108and a cathode of diode D2. A cathode of diode D1is coupled to voltage supply node104, ESD clamp circuit120and node Nd1. In some embodiments, the cathode of diode D1is coupled to ESD clamp circuit120by node Nd1. In some embodiments, diode D1is a pull-up diode or referred to as a p+ diode. For example, in these embodiments, the p+-diode is formed between a p-well region (e.g., well322ofFIGS.3A-3B) and an n-well region (not shown), and the n-well region is connected to VDD (SeeFIGS.3A-3B). In some embodiments, diode D1is a vertical well diode. Other diode types for diode D1are within the scope of the present disclosure. Diode D2is coupled between reference voltage supply node106and IO pad108. Diode D2is coupled between node Nd3and node Nd2. An anode of diode D2is coupled to reference voltage supply node106, ESD clamp circuit120and node Nd2. A cathode of diode D2is coupled to node Nd3, IO circuit110, IO pad108and the anode of diode D1. In some embodiments, diode D2is a pull-down diode or referred to as an n+ diode. For example, in these embodiments, the n+-diode is formed between an n-well region (e.g., well332ofFIGS.3A-3B) and a p-well (not shown), and the P-substrate is connected to ground or VSS. In some embodiments, diode D2is a vertical well diode. Other diode types for diode D2are within the scope of the present disclosure. Diodes D1and D2are configured to have a minimal impact on the normal behavior (e.g., no ESD conditions or events) of internal circuit102or integrated circuit100. In some embodiments, an ESD event occurs when an ESD voltage or current higher than a level of voltage or current expected during the normal operation of internal circuit102is applied to at least voltage supply node104, reference voltage supply node106or IO pad108. When no ESD events occur, diodes D1and D2do not affect the operation of integrated circuit100. During an ESD event, diode D1is configured to transfer voltage or current between voltage supply node104and IO pad108dependent upon whether diode D1is forward biased or reverse biased, and the voltage levels of the voltage supply node104and IO pad108. For example, during a Positive-to-VDD (PD) mode of ESD stress or event, diode D1is forward biased and is configured to transfer voltage or current from IO pad108to voltage supply node104. In PD-mode, a positive ESD stress or ESD voltage (at least greater than supply voltage VDD) is applied to IO pad108, while voltage supply node104(e.g., VDD) is ground and reference voltage supply node106(e.g., VSS) is floating. For example, during a Negative-to-VDD (ND) mode of ESD stress or event, diode D1is reverse biased and is configured to transfer voltage or current from voltage supply node104to IO pad108. In ND-mode, a negative ESD stress is received by IO pad108, while the voltage supply node104(e.g., VDD) is ground and reference voltage supply node106(e.g., VSS) is floating. During an ESD event, diode D2is configured to transfer voltage or current between reference voltage supply node106and IO pad108dependent upon whether diode D2is forward biased or reverse biased, and the voltage levels of the reference voltage supply node106and IO pad108. For example, during a Positive-to-VSS (PS) mode of ESD stress or event, diode D2is reverse biased and is configured to transfer voltage or current from IO pad108to reference voltage supply node106. In PS-mode, a positive ESD stress or ESD voltage (at least greater than reference supply voltage VSS) is applied to IO pad108, while voltage supply node104(e.g., VDD) is floating and reference voltage supply node106(e.g., VSS) is ground. For example, during a Negative-to-VSS (NS) mode of ESD stress or event, diode D2is forward biased and is configured to transfer voltage or current from reference voltage supply node106to IO pad108. In NS-mode, a negative ESD stress is received by IO pad108, while the voltage supply node104(e.g., VDD) is floating and reference voltage supply node106(e.g., VSS) is ground. Other types of diodes, configurations and arrangements of at least diode D1or D2are within the scope of the present disclosure. IO circuit110is coupled to IO pad108, internal circuit102, diodes D1and D2and node Nd3. IO circuit is coupled between node Nd3and internal circuit102. In some embodiments, IO circuit is an IO buffer configured to buffer signals sent to or from internal circuit102. In some embodiments, IO circuit110includes at least the logic gate cell described above. Other types of circuits, configurations and arrangements of IO circuit110are within the scope of the present disclosure. ESD clamp circuit120is coupled between voltage supply node104(e.g. supply voltage VDD) and reference voltage supply node106(e.g., VSS). ESD clamp circuit120is coupled between node Nd1and node Nd2. ESD clamp circuit120is coupled to diode D1by node Nd1. ESD clamp circuit120is coupled to diode D2by node Nd2. When no ESD event occurs, ESD clamp circuit120is turned off. For example, when no ESD event occurs, ESD clamp circuit120is turned off, and is therefore a nonconductive device or circuit during the normal operation of internal circuit102. In other words, ESD clamp circuit120is turned off or is non-conductive in the absence of an ESD event. If an ESD event occurs, ESD clamp circuit120is configured to sense the ESD event, and is configured to turn on and provide a current shunt path between voltage supply node104(e.g. supply voltage VDD) or node Nd1and reference voltage supply node106(e.g., VSS) or node Nd2to thereby discharge the ESD current. For example, when an ESD event occurs, the voltage difference across the ESD clamp circuit120is equal to or greater than a threshold voltage of ESD clamp circuit120, and ESD clamp circuit120is turned on thereby conducting current between voltage supply node104(e.g. VDD) and reference voltage supply node106(e.g., VSS). During an ESD event, ESD clamp circuit120is configured to turn on and discharge an ESD current in a forward ESD direction (e.g., current I1a) from the reference voltage supply node106(e.g., VSS) to the voltage supply node104(e.g. VDD). Current I1ais shown inFIG.1between node Nd2to node Nd1for simplicity, but it is understood that current I1ais from the reference voltage supply node106(e.g., VSS) to the voltage supply node104(e.g. VDD). During an ESD event, ESD clamp circuit120is configured to turn on and discharge an ESD current in a reverse ESD direction (e.g., current I2a) from the voltage supply node104(e.g. VDD) to the reference voltage supply node106(e.g., VSS). Current I2ais shown inFIG.1between node Nd1to node Nd2for simplicity, but it is understood that current I2ais from the voltage supply node104(e.g. VDD) to the reference voltage supply node106(e.g., VSS). During a positive ESD surge on reference voltage supply node106, ESD clamp circuit120is configured to turn on and discharge the ESD current I1ain a forward ESD direction from the reference voltage supply node106(e.g., VSS) to the voltage supply node104(e.g. VDD). In some embodiments, ESD clamp circuit120is configured to turn on, after a PS mode (described above) of ESD, and discharge the ESD current I1in the forward ESD direction from node Nd3to node Nd2, and from node Nd2to the voltage supply node104(e.g. VDD) by node Nd1. During a positive ESD surge on voltage supply node104, ESD clamp circuit120is configured to turn on and discharge the ESD current I2ain a reverse ESD direction from voltage supply node104(e.g. VDD) to reference voltage supply node106(e.g., VSS). In some embodiments, ESD clamp circuit120is configured to turn on, after a PD mode (described above) of ESD, and discharge the ESD current I2in the reverse ESD direction from node Nd3to node Nd1, and from node Nd1to the reference voltage supply node106(e.g., VSS) by node Nd2. In some embodiments, ESD clamp circuit120is a transient clamp. For example, in some embodiments, ESD clamp circuit120is configured to handle transient or ESD events, e.g., rapid changes in voltage and/or current from the ESD event. During the transient or ESD, the ESD clamp circuit120is configured to turn on to provide a shunt path between voltage supply node104(e.g. supply voltage VDD) and reference voltage supply node106(e.g., VSS) before the ESD event can cause damage to one or more elements within integrated circuit100. In some embodiments, ESD clamp circuit120is configured to turn off slower than it turns on. In some embodiments, ESD clamp circuit120is a static clamp. In some embodiments, static clamps are configured to provide a static or steady-state voltage and current response. For example, static clamps are turned-on by a fixed voltage level. In some embodiments, ESD clamp circuit120includes a large NMOS transistor configured to carry the ESD current without entering the avalanche breakdown region of the ESD clamp circuit120. In some embodiments, ESD clamp circuit120is implemented without having avalanching junctions inside ESD clamp circuit120, and is also known as a “non-snapback protection scheme.” Other types of clamp circuits, configurations and arrangements of ESD clamp circuit120are within the scope of the present disclosure. Other configurations or quantities of circuits in integrated circuit100are within the scope of the present disclosure. FIG.2is a schematic block diagram of an integrated circuit200, in accordance with some embodiments. Integrated circuit200is an embodiment of integrated circuit100, and similar detailed description is therefore omitted. For example, integrated circuit200includes at least a portion of integrated circuit100included as part of a substrate202. While integrated circuit200ofFIG.2shows a portion of integrated circuit100, it is understood that integrated circuit200can be modified to include each of the features of integrated circuit100, and similar detailed description is therefore omitted for brevity. Components that are the same or similar to those in one or more ofFIGS.1,2,3A-3B and4(shown below) are given the same reference numbers, and detailed description thereof is thus omitted. Integrated circuit200includes voltage supply node104, reference voltage supply node106, IO pad108, diode D1, diode D2, substrate202and a clamp circuit220. Integrated circuit200is a variation of integrated circuit100ofFIG.1, and similar detailed description is therefore omitted. In comparison with integrated circuit100, ESD clamp circuit220replaces ESD clamp circuit120ofFIG.1, and similar detailed description is therefore omitted. ESD clamp circuit220are formed on substrate202. Substrate202extends in a first direction X. Substrate202has a backside203and a front side205opposite from the backside203in a second direction Y. In some embodiments, the second direction Y is different from the first direction X. In some embodiments, a bulk of substrate202has been removed during wafer thinning. In some embodiments, substrate202is part of a super power rail (SPR) technology or process. In some embodiments, substrate202is a silicon on insulator (SOI) technology or process. In some embodiments, at least diode D1or D2is formed on substrate202. Other types of substrate technology or processes for substrate202are within the scope of the present disclosure. ESD clamp circuit220includes a signal tap250and a signal tap252. In some embodiments, at least signal tap252corresponds to a well tap. In some embodiments, a well tap is an electrically conductive lead that couples a well region (shown inFIG.3A-3B) of substrate202to voltage supply node104(e.g., supply voltage VDD). For example, in some embodiments, the well region includes a heavily doped n-region in an n-type well on a p-type substrate. In some embodiments, the heavily doped n-region is coupled through the well tap to voltage supply node104(e.g., supply voltage VDD) thereby setting the potential of the n-type well to prevent leakage from adjacent source/drain regions into the well. In some embodiments, at least signal tap250corresponds to a substrate tap. In some embodiments, a substrate tap is an electrically conductive lead that couples a region of substrate202to reference voltage supply node106(e.g., reference supply voltage VSS). For example, in some embodiments, the region of substrate202includes a heavily doped p-region which is formed in a p-type substrate. In some embodiments, the heavily doped p-region is coupled through the substrate tap to the reference voltage supply node106(e.g., reference supply voltage VSS) thereby setting the potential of the substrate202to prevent leakage from adjacent source/drain regions. Through the use of signal taps250and252the resistance of substrate202and undesirable positive feedback in integrated circuit200are reduced. In some embodiments, at least signal tap250or252is configured to limit a resistance between power or ground connections to wells (shown inFIGS.3A-3B) of substrate202. In some embodiments, the use of at least signal tap250or252results in less drift in substrate202thereby preventing latch-up effects. Signal tap250is coupled to the voltage supply node104(e.g., voltage VDD) on the backside203of substrate202. Signal tap250is further coupled to the cathode of diode D1. Signal tap252is coupled to the reference voltage supply node106(e.g., voltage VSS) on the backside203of substrate202. Signal tap252is further coupled to the anode of diode D2. IO pad108is on the backside203of substrate202, and is coupled to the anode of diode D1and the cathode of diode D2. In some embodiments, integrated circuit200is electrically connected to one or more other package structures (not shown) on the backside203of substrate202. In some embodiments, diode D1is configured to share signal tap250with ESD clamp circuit220, and diode D2is configured to share signal tap252with ESD clamp circuit220. In some embodiments, by sharing signal tap250with ESD clamp circuit220, diode D1does not include a signal tap resulting in integrated circuit200occupying less area than other approaches. In some embodiments, by sharing signal tap252with ESD clamp circuit220, diode D2does not include a signal tap resulting in integrated circuit200occupying less area than other approaches. By at least diode D1or D2not including corresponding signal taps, integrated circuit200has less resistance since integrated circuit200includes fewer signal taps than other approaches. Other types of clamp circuits, configurations and arrangements of ESD clamp circuit120are within the scope of the present disclosure. Other configurations or quantities of circuits in integrated circuit200are within the scope of the present disclosure. FIG.3Ais a cross-sectional view of an integrated circuit300A, in accordance with some embodiments. Integrated circuit300A is an embodiment of at least integrated circuit100ofFIG.1or integrated circuit200ofFIG.2, and similar detailed description is therefore omitted. WhileFIGS.3A-3Bare described with respect to a portion of integrated circuit100ofFIG.1or integrated circuit200ofFIG.2, the teachings ofFIGS.3A-3Bare also applicable to other portions of integrated circuit100or200(not described with respect to at leastFIGS.3A-3B), and similar detailed description is therefore omitted for brevity. Integrated circuit300A includes a diode302, a diode304, an ESD clamp circuit310and a substrate320. Diode302is an embodiment of diode D1ofFIGS.1-2, diode304is an embodiment of diode D2ofFIGS.1-2, ESD clamp circuit310is an embodiment of ESD clamp circuit120ofFIG.1or210ofFIG.2, and substrate320is an embodiment of substrate202ofFIG.2, and similar detailed description is therefore omitted. At least diode302, diode D2or ESD clamp circuit310is formed on substrate320. In some embodiments, at least diode302, diode D2or ESD clamp circuit310is formed on a front side305of substrate320. Substrate320has a front side305and a backside303opposite from the front side305in a second direction Y. Substrate320has a side326and a side336opposite from side326in the first direction X. In some embodiments, a bulk of substrate320has been removed during wafer thinning. In some embodiments, substrate320is part of a super power rail (SPR) technology or process. In some embodiments, substrate320is a silicon on insulator (SOI) technology or process. In some embodiments, substrate320is also referred to as a wafer. In some embodiments, substrate320includes an insulating layer321. Insulating layer321is between the back-side303and front-side305of substrate320. In some embodiments, the insulating layer321is a non-conducting oxide material. In some embodiments, the insulating layer321is formed on the back-side303of substrate320after wafer thinning and oxide regrowth. In some embodiments, the front-side305and the back-side303are electrically isolated from each other by at least the insulating layer321. In some embodiments, the insulating layer321includes a dielectric material including oxide or another suitable insulating material. Substrate320is a p-type substrate. In some embodiments, substrate320is an n-type substrate. In some embodiments, substrate320includes an elemental semiconductor including silicon or germanium in crystal, polycrystalline, or an amorphous structure; a compound semiconductor including silicon carbide, gallium arsenic, gallium phosphide, indium phosphide, indium arsenide, and indium antimonide; an alloy semiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and GaInAsP; any other suitable material; or combinations thereof. In some embodiments, the alloy semiconductor substrate has a gradient SiGe feature in which the Si and Ge composition change from one ratio at one location to another ratio at another location of the gradient SiGe feature. In some embodiments, the alloy SiGe is formed over a silicon substrate. In some embodiments, substrate320is a strained SiGe substrate. In some embodiments, the semiconductor substrate has a semiconductor on insulator structure, such as a silicon on insulator (SOI) structure. In some embodiments, the semiconductor substrate includes a doped epi layer or a buried layer. In some embodiments, the compound semiconductor substrate has a multilayer structure, or the substrate includes a multilayer compound semiconductor structure. Diode302includes an anode302a, a gate structure302b, a cathode302c, a cathode302d, a channel region302eand a well322. Diode302is a vertical well diode. In some embodiments, diode302is a nanosheet vertical well diode. In some embodiments, diode302is formed on a front side305of substrate320. Other diode types for diode302are within the scope of the present disclosure. Diode302corresponds to diode D1ofFIGS.1-2, and similar detailed description is omitted. Anode302acorresponds to the anode of diode D1ofFIGS.1-2, cathodes302cand302dcorresponds to the cathode of diode D1ofFIGS.1-2, and the channel region302ecorresponds to a channel region of diode D1, and similar detailed description is omitted. Well322is formed in substrate320. Well322has p-type dopant impurities and is referred to as a P-type well. In some embodiments, well322has n-type dopant impurities and is referred to as an N-type well. Well322includes a region324. Region324is embedded in well322. Region324is a heavily doped p-region. In some embodiments, region324is a heavily doped n-region. The anode302aincludes well322and region324. The anode302ais a P-type active region having P-type dopants in well322. The cathode302cis an N-type active region having N-type dopants and is located on well322. The cathode302dis an N-type active region having N-type dopants and is located on well322. In some embodiments, at least cathode302cor302dis a P-type active region having P-type dopants. The cathode302cand the cathode302dare separated from each other in the first direction X. In some embodiments, cathode302cand cathode302dare corresponding cathodes of two diodes coupled together in parallel. Integrated circuits300A-300B are shown with two cathodes (e.g., cathodes302cand302d) and a single anode (e.g., anode302a). Other number of cathodes302cor302dand/or anodes302aare within the scope of the present disclosure. The anode302aand the cathode302ctogether form a PN junction, and the anode302aand the cathode302dtogether form another PN junction. In some embodiments, at least cathode302cor cathode302dextends above substrate320. In some embodiments, at least a top surface of cathode302cor a top surface of cathode302dis flush with the front side305of substrate320. The gate structure302bis at least partially over well322, and in between cathode302cand cathode302d. In some embodiments, the gate structure302bis electrically floating. In some embodiments, the gate structure302bis electrically coupled to cathodes302cand302d. The channel region302ecouples the cathode302cand the cathode302d. In some embodiments, the channel region302eis in well322. In some embodiments, diode302does not include a signal tap region. In some embodiments, diode302is configured to share a signal tap region350with ESD clamp circuit310. For example, in some embodiments, diode302is electrically coupled to the signal tap region350of ESD clamp circuit310by at least a conductive structure390. In some embodiments, by sharing signal tap region350with ESD clamp circuit310, integrated circuit300A or300B occupies less area than other approaches. In some embodiments, by sharing signal tap region350with ESD clamp circuit310, integrated circuit300A or300B has less signal taps than other approaches resulting in integrated circuit300A or300B having less resistance than other approaches, and simpler routing. Other types of circuits, configurations and arrangements of diode302are within the scope of the present disclosure. Diode304includes an anode304a, a gate structure304b, a cathode304c, a cathode304d, a channel region304eand a well332. Diode304is a vertical well diode. In some embodiments, diode304is a nanosheet vertical well diode. In some embodiments, diode304is formed on a front side305of substrate320. Other diode types for diode304are within the scope of the present disclosure. Diode304corresponds to diode D2ofFIGS.1-2, and similar detailed description is omitted. Anode304acorresponds to the anode of diode D2ofFIGS.1-2, cathodes304cand304dcorresponds to the cathode of diode D2ofFIGS.1-2, and the channel region304ecorresponds to a channel region of diode D2, and similar detailed description is omitted. Well332is formed in substrate320. Well332has n-type dopant impurities and is referred to as an N-type well. In some embodiments, well332has p-type dopant impurities and is referred to as a P-type well. Well332includes a region334. Region334is embedded in well332. Region334is a heavily doped n-region. In some embodiments, region334is a heavily doped p-region. The anode304aincludes well332and region334. The anode304ais an N-type active region having N-type dopants in well332. The cathode304cis a P-type active region having P-type dopants and is located on well332. The cathode304dis a P-type active region having P-type dopants and is located on well332. In some embodiments, at least cathode304cor304dis an N-type active region having N-type dopants. The cathode304cand the cathode304dare separated from each other in the first direction X. In some embodiments, cathode304cand cathode304dare corresponding cathodes of two diodes coupled together in parallel. Integrated circuits300A-300B are shown with two cathodes (e.g., cathodes304cand304d) and a single anode (e.g., anode304a). Other number of cathodes304cor304dand/or anodes304aare within the scope of the present disclosure. The anode304aand the cathode304ctogether form a PN junction, and the anode304aand the cathode304dtogether form another PN junction. In some embodiments, at least cathode304cor cathode304dextends above substrate320. In some embodiments, at least a top surface of cathode304cor a top surface of cathode304dis flush with the front side305of substrate320. The gate structure304bis at least partially over well332, and in between cathode304cand cathode304d. In some embodiments, the gate structure304bis electrically floating. In some embodiments, the gate structure304bis electrically coupled to cathodes304cand304d. The channel region304ecouples the cathode304cand the cathode304d. In some embodiments, the channel region304eis in well332. In some embodiments, diode304does not include a signal tap region. In some embodiments, diode304is configured to share a signal tap region352with ESD clamp circuit310. For example, in some embodiments, diode304is electrically coupled to the signal tap region352of ESD clamp circuit310by at least a conductive structure392. In some embodiments, by sharing signal tap region352with ESD clamp circuit310, integrated circuit300A or300B occupies less area than other approaches. In some embodiments, by sharing signal tap region352with ESD clamp circuit310, integrated circuit300A or300B has less signal taps than other approaches resulting in integrated circuit300A or300B having less resistance than other approaches, and simpler routing. Other types of circuits, configurations and arrangements diode304are within the scope of the present disclosure. ESD clamp circuit310includes an N-type Metal Oxide Semiconductor (NMOS) transistor N1, an NMOS transistor N2, signal tap region250and signal tap region252. NMOS transistor N1is coupled in series with NMOS transistor N2. For ease of illustration, NMOS transistor N1and NMOS transistor N2are not shown as being coupled to other elements inFIGS.3A-3B. In some embodiments, at least NMOS transistor N1or N2is a P-type Metal Oxide Semiconductor (PMOS) transistor. NMOS transistor N1includes a drain region310a, a gate structure310b, a source region310c, a channel region310dand a well region360. Well region360is formed in substrate320. Well region360has p-type dopant impurities and is referred to as a P-type well. In some embodiments, well region360has n-type dopant impurities and is referred to as an N-type well. The gate structure310bis over well region360. The drain region310ais an N-type active region having N-type dopants implanted in well region360. The source region310cis an N-type active region having N-type dopants implanted in well region360. In some embodiments, at least source region310cor drain region310aextends above substrate320. The channel region310dis in well region360and couples the drain region310aand the source region310c. NMOS transistor N2includes a drain region312a, a gate structure312b, a source region312c, a channel region312dand a well region362. Well region362is formed in substrate320. Well region362has p-type dopant impurities and is referred to as a P-type well. In some embodiments, well region362has n-type dopant impurities and is referred to as an N-type well. The gate structure312bis over well region362. The drain region312ais an N-type active region having N-type dopants implanted in well region362. The source region312cis an N-type active region having N-type dopants implanted in well region362. In some embodiments, at least source region312cor drain region312aextends above substrate320. The channel region312dis in well region362and couples the drain region312aand the source region312c. The signal tap region350is an embodiment of signal tap region250ofFIG.2, and the signal tap region352is an embodiment of signal tap region252ofFIG.2, and similar detailed description is therefore omitted. The signal tap region350is in well region360. Signal tap region350is coupled to a conductive structure344. Each of signal tap region350and conductive structure344are coupled to node Nd1which corresponds to the voltage supply terminal (e.g., voltage VDD). Signal tap region350is further coupled to cathode302cof diode D1and cathode302dof diode D1by a conductive line390. In some embodiments, the signal tap region350of ESD clamp circuit310is shared with diode302. In some embodiments, signal tap region350is a well tap, and electrically couples well region360of substrate320to voltage supply node104(e.g., supply voltage VDD). In some embodiments, the signal tap region350includes a heavily doped n-region in well region360on substrate320(e.g., P-type). In some embodiments, the heavily doped n-region is coupled through the well tap to voltage supply node104(e.g., supply voltage VDD) thereby setting the potential of the well region360(e.g., N-type) to prevent leakage from adjacent source/drain regions into well region360. In some embodiments, the signal tap region350includes a heavily doped p-region in well region360on substrate320. The signal tap region352is in well region362. In some embodiments, well region362and360are part of a same continuous well. In some embodiments, well region362and360are separate discontinuous wells. Signal tap region352is coupled to a conductive structure346. Each of signal tap region352and conductive structure346are coupled to node Nd2which corresponds to the reference voltage supply terminal (e.g., voltage VSS). Signal tap region352is further coupled to cathode304cof diode D2and cathode304dof diode D2by a conductive line392. In some embodiments, signal tap region352of ESD clamp circuit310is shared with diode304. In some embodiments, signal tap region352is a substrate tap, and electrically couples well region362of substrate320to reference voltage supply node106(e.g., supply voltage VSS). In some embodiments, the signal tap region352includes a heavily doped p-region in well region362on substrate320(e.g., P-type). In some embodiments, the heavily doped p-region is coupled through the substrate tap to reference voltage supply node106(e.g., supply voltage VSS) thereby setting the potential of the substrate320(e.g., P-type) to prevent leakage from adjacent source/drain regions. In some embodiments, the signal tap region352includes a heavily doped n-region in well region362on substrate320. Each of the cathode302cof diode D1, the cathode302dof diode D1, and the signal tap region350are coupled together by conductive line390that corresponds to node Nd1ofFIGS.1-2. Each of the cathode304cof diode D2, the cathode304dof diode D2, and the signal tap region352are coupled together by conductive line392that corresponds to node Nd2ofFIGS.1-2. In some embodiments, the drain region310aand source region310cor the drain region312aand source region312cof ESD clamp circuit310ofFIGS.3A-3Bis referred to as an oxide definition (OD) region which defines the source or drain diffusion regions of NMOS transistor N1or N2ofFIGS.3A-3B. In some embodiments, at least drain region310aor312ais an extended drain region and has a greater size than at least source region310cor312c. In at least one embodiment, a silicide layer (not shown) covers a portion, but not the entirety, of at least drain region310aor312a. Such a partially silicided configuration of drain region310aimproves self-protection of NMOS transistor N1or N2of ESD clamp circuit310from ESD events. In at least one embodiment, at least drain region310aor312ais fully silicided. Gate structure310bis arranged between drain region310aand source region310c. Gate structure312bis arranged between drain region312aand source region312c. In some embodiments, the gate structure310band gate structure312bare electrically coupled together. In some embodiments, at least gate structure302b,304b,310bor312bis a metal gate, and includes a conductive material such as a metal. In some embodiments, at least gate structure302b,304b,310bor312bincludes polysilicon (also referred to herein as “POLY”). In some embodiments, at least channel region302e,304e,310dor312dincludes fins in accordance with fin field-effect transistor (FinFET) complementary metal-oxide-semiconductor (CMOS) technologies. In some embodiments, at least channel region302e,304e,310dor312dincludes nanosheets of nanosheet transistors. In some embodiments, at least channel region302e,304e,310dor312dincludes nanowire of nanowire transistors. In some embodiments, at least channel region302e,304e,310dor312dis free of fins in accordance with planar CMOS technologies. Other types of transistors are within the scope of the present disclosure. Other types of circuits, configurations and arrangements of ESD clamp circuit310are within the scope of the present disclosure. Integrated circuit300A further includes one or more shallow trench isolation (STI) regions328a,328b,328cor328d. STI region328ais adjacent to anode304aof diode304. STI region328bis between diode302and ESD clamp circuit310. STI region328cis between diode304and ESD clamp circuit310. STI region328dis adjacent to cathode302dof diode302. STI region328ais configured to electrically isolate portions of diode304from other portions of integrated circuit300A or300B (not shown). STI region328bis configured to electrically isolate portions of diode304and portions of ESD clamp circuit310from each other. In some embodiments, STI region328cis configured to electrically isolate at least portions of diode302and portions of ESD clamp circuit310from each other. STI region328dis configured to electrically isolate portions of diode302from other portions of integrated circuit300A or300B (not shown). In some embodiments, at least STI region328a,328b,328cor328dis not included in integrated circuit300A or300B. In some embodiments, in at least integrated circuit300A or300B, at least STI region328a,328b,328cor328dis replaced with a corresponding dummy cell. In some embodiments, the dummy cell is a dummy device. In some embodiments, a dummy device is a non-functional transistor or non-functional diode device. In some embodiments, well region322and well region360are part of a same continuous well. In some embodiments, well region322and360are separate discontinuous wells, and STI region328is positioned between them. In some embodiments, well region332and well region362are part of a same continuous well. In some embodiments, well region322and362are separate discontinuous wells, and STI region338is positioned between them. In some embodiments, well region360is positioned between well region362and well region322. In some embodiments, well region360is adjacent to at least well region362or well region322. In some embodiments, a first element is adjacent to a second element corresponds to the first element being directly next to the second element. In some embodiments, the first element is adjacent to the second element corresponds to the first element not being directly next to the second element. In some embodiments, diode302is adjacent to ESD clamp circuit310. In some embodiments, signal tap region350is adjacent to cathode302c. In some embodiments, well region362is positioned between well region360and well region332. In some embodiments, well region362is adjacent to at least well region360or well region332. In some embodiments, diode304is adjacent to ESD clamp circuit310. In some embodiments, signal tap region352is adjacent to cathode304c. Other types of circuits, configurations and arrangements of ESD clamp circuit310are within the scope of the present disclosure. Integrated circuit300A further includes a conductive structure340, a conductive structure342, a conductive structure344and a conductive structure346. Conductive structure340, conductive structure342, conductive structure344and conductive structure346are formed on the backside203of integrated circuits300A-300B. In some embodiments, at least conductive structure340, conductive structure342, conductive structure344or conductive structure346is embedded in substrate320. In some embodiments, at least conductive structure340, conductive structure342, conductive structure344or conductive structure346is configured to provide an electrical connection between one or more circuit elements of integrated circuit300A-300B and other one or more circuit elements of integrated circuit300A-300B or other package structures (not shown). In some embodiments, each of conductive structure340, conductive structure342and conductive structure344and conductive structure346is a corresponding via. In some embodiments, one or more of conductive structure340, conductive structure342and conductive structure344, conductive structure346or signal tap350are used to electrically couple signals from the front-side305to the back-side303of substrate320since the front-side305and the back-side303are electrically isolated from each other by at least the insulating layer321. In some embodiments, at least conductive structure340,342,344or346is directly coupled with corresponding source/drain region310a,310cor312c. In some embodiments, integrated circuit300A is electrically connected to one or more other package structures (not shown) on the backside203of substrate320by at least conductive structure340, conductive structure342, conductive structure344or conductive structure346. In some embodiments, at least conductive structure340, conductive structure342, conductive structure344or conductive structure346corresponds to a copper pillar structure that includes at least a conductive material such as copper, or the like. In some embodiments, at least conductive structure340, conductive structure342, conductive structure344or conductive structure346corresponds to a solder bump structure that includes a conductive material having a low resistivity, such as solder or a solder alloy. In some embodiments, a solder alloy includes Sn, Pb, Ag, Cu, Ni, Bi, or combinations thereof. Other configurations, arrangements and materials of at least conductive structure340, conductive structure342, conductive structure344or conductive structure346are within the contemplated scope of the present disclosure. Conductive structure340is coupled to the anode region302aof diode302. Conductive structure340is coupled to the well region322and region324of diode302. In some embodiments, conductive structure340corresponds to node Nd3ofFIGS.1-2. In some embodiments, conductive structure340is electrically coupled to node Nd3ofFIGS.1-2. In some embodiments, conductive structure340is electrically coupled to IO pad108ofFIGS.1-2. Conductive structure342is coupled to the anode region304aof diode304. Conductive structure342is coupled to the well region332and region334of diode304. In some embodiments, conductive structure342corresponds to node Nd3ofFIGS.1-2. In some embodiments, conductive structure342is electrically coupled to node Nd3ofFIGS.1-2. In some embodiments, conductive structure342is electrically coupled to IO pad108ofFIGS.1-2. In some embodiments, conductive structure340and conductive structure342are coupled to each other. For ease of illustration, conductive structure340and conductive structure342are not shown as being coupled to each other. Conductive structure344is coupled to signal tap region350. Conductive structure344is configured to provide voltage VDD to signal tap region350. In some embodiments, conductive structure344is electrically coupled to voltage supply node104(e.g., voltage VDD) ofFIGS.1-2. In some embodiments, conductive structure344corresponds to node Nd1ofFIGS.1-2. In some embodiments, conductive structure344corresponds to a pad or a pin. In some embodiments, conductive structure344is electrically coupled to node Nd1ofFIGS.1-2. In some embodiments, conductive structure344corresponds to node Nd1ofFIGS.1-2. Conductive structure346is coupled to signal tap region352. Conductive structure346is configured to provide voltage VSS to signal tap region352. In some embodiments, conductive structure346is electrically coupled to reference voltage supply node106(e.g., voltage VSS) ofFIGS.1-2. In some embodiments, conductive structure346corresponds to node Nd2ofFIGS.1-2. In some embodiments, conductive structure346corresponds to a pad or a pin. In some embodiments, conductive structure346is electrically coupled to node Nd2ofFIGS.1-2. In some embodiments, conductive structure346corresponds to node Nd2ofFIGS.1-2. In some embodiments, at least conductive structure340,342,344,346,390or392includes one or more layers of a conductive material. In some embodiments, the conductive material includes Tungsten, Cobalt, Ruthenium, Copper, or the like or combinations thereof. Other configurations, arrangements and materials of at least conductive structure340,342,344,346,390or392are within the contemplated scope of the present disclosure. Other configurations or quantities of circuits in integrated circuit300A are within the scope of the present disclosure. During a PD mode of ESD stress or event, diode302is forward biased and current I2flows through diode302from the anode302ato the cathode302cand cathode302d. Diode302is configured to transfer current I2or ESD voltage from IO pad108(node Nd3) to node Nd1. Current I2flows directly from cathode302cand cathode302dto signal tap region350of ESD clamp circuit302. In response to current I2and ESD voltage at node Nd1, NMOS transistors N1and N2in ESD clamp circuit310are configured to turn on, and discharge the ESD current I2from signal tap region350or node Nd1through channel regions310dand312dto the reference voltage supply node106(e.g., VSS) by signal tap region352and node Nd2. In some embodiments, by sharing signal tap region350with ESD clamp circuit310, integrated circuit300A has less signal taps than other approaches, resulting in current I2flowing through less signal taps than other approaches, and to flow directly from cathode302cand cathode302dto signal tap region350of ESD clamp circuit320thereby reducing the signal tap resistance of integrated circuit300A compared to other approaches. FIG.3Bis a cross-sectional view of an integrated circuit300B, in accordance with some embodiments. Integrated circuit300B is an embodiment of at least ESD clamp circuit120or310, and similar detailed description is therefore omitted. Integrated circuit300B is an embodiment of integrated circuit300B, and similar detailed description is therefore omitted. Integrated circuit300B is an embodiment of at least integrated circuit100ofFIG.1or integrated circuit200ofFIG.2, and similar detailed description is therefore omitted. Integrated circuit300B is a variation of integrated circuit300A ofFIG.3A, and similar detailed description is therefore omitted. In comparison with integrated circuit300A, current I1replaces current I2, and similar detailed description is therefore omitted. In other words, integrated circuit300B is configured to show ESD current flow during a PS mode of ESD stress. During a PS mode of ESD stress or event, diode304is reverse biased and current I1flows through diode304from the anode304ato the cathode304cand cathode304d. Diode304is configured to transfer current I1or ESD voltage from IO pad108(node Nd3) to node Nd2. Current I1flows directly from cathode304cand cathode304dto signal tap region352of ESD clamp circuit302. In response to current I1and ESD voltage at node Nd2, NMOS transistors N2and N1in ESD clamp circuit310are configured to turn on, and discharge the ESD current I1from signal tap region352or node Nd2through channel regions312dand310dto the voltage supply node104(e.g., VDD) by signal tap region350and node Nd1. In some embodiments, by sharing signal tap region352with ESD clamp circuit310, integrated circuit300B has less signal taps than other approaches, resulting in current I1flowing through less signal taps than other approaches, and to flow directly from cathode304cand cathode304dto signal tap region352of ESD clamp circuit320thereby reducing the signal tap resistance of integrated circuit300B compared to other approaches. Other configurations or quantities of circuits in integrated circuit300B are within the scope of the present disclosure. FIG.4is a circuit diagram of an integrated circuit400, in accordance with some embodiments. Integrated circuit400is an embodiment of at least ESD clamp circuit120ofFIG.1, and similar detailed description is therefore omitted. In some embodiments, integrated circuit400is an equivalent circuit for ESD clamp circuit310ofFIGS.3A-3B. In some embodiments, NMOS transistor N1ofFIG.4corresponds to NMOS transistor N1ofFIGS.3A-3B, and NMOS transistor N2ofFIG.4corresponds to NMOS transistor N2ofFIGS.3A-3B. Integrated circuit400includes a resistor R1, a capacitor C1, an inverter I1, an NMOS transistor N1and an NMOS transistor N2. In some embodiments, NMOS transistor N1and NMOS transistor N2are referred to as an ESD discharging circuit that is configured to couple node Nd1and Nd2during an ESD event at node Nd1or node Nd2, thereby providing an ESD discharge path between node Nd1and Nd2. Each of a first end of resistor R1, node Nd1, a first voltage supply node (not labelled) of inverter I1and a drain of NMOS transistor N1are coupled together. Each of a second end of resistor R1, a first end of capacitor C1, an input terminal of inverter I1and a node Nd4are coupled together. Each of a second end of capacitor C1, node Nd2, a source of NMOS transistor N2, a body of NMOS transistor N1, a body of NMOS transistor N2and a second voltage supply node (not labelled) of inverter I1are coupled together. An output terminal of inverter I1is coupled to a gate of NMOS transistor N1and a gate of NMOS transistor N2. In some embodiments, capacitor C1is a transistor-coupled capacitor. For example in some embodiments, capacitor C1is a transistor having a drain and source coupled together thereby forming a transistor-coupled capacitor. Resistor R1and capacitor C1are configured as an RC network. Dependent upon a location of an output of the RC network, the RC network is configured as either a low pass filter or a high pass filter. In some embodiments, inverter I1includes an NMOS transistor (not shown) and a PMOS transistor (not shown) coupled together as an inverter circuit. Thus, a slowly rising voltage at node Nd4will be inverted by inverter I1thereby causing node Nd3to rapidly rise. Furthermore, a rapidly rising voltage at node Nd4will be inverted by inverter I1thereby causing node Nd3to rise slowly. In some embodiments, inverter I1is configured to generate an inverted input signal (not shown) in response to an input signal (not shown). When an ESD event at node Nd1occurs (e.g., ESD current I2ain the reverse ESD direction), the ESD current or voltage at node Nd1rises rapidly causing the voltage of node Nd4(e.g., across capacitor C1) to rise slowly (e.g., slower than rapidly) since the voltage at node Nd4corresponds to an output voltage of a low pass filter (e.g., a voltage across capacitor C1with respect to node Nd2). In other words, capacitor C1is configured as a low pass filter, and the rapidly changing voltage or current from the ESD event is filtered by capacitor C1. In response to the slowly rising voltage at node Nd4, a PMOS transistor (not shown) in inverter I1will turn on thereby coupling node Nd3to node Nd1and causing node Nd3to rapidly rise from the ESD event at node Nd1. Thus, node Nd3and the gate of NMOS transistors N1and N2are charged by the ESD event at node Nd1. In response to being charged by the ESD event at node Nd3, NMOS transistors N1and N2turn on and couple node Nd1to node Nd2. By being turned on and coupling node Nd1to node Nd2, the channels of NMOS transistors N1and N2discharge the ESD current I2ain the reverse ESD direction from node Nd1to Nd2. When an ESD event at node Nd2occurs (e.g., ESD current I1aflows in the forward ESD direction), the ESD current or voltage at node Nd2rises rapidly, causing the voltage of node Nd4(e.g., across capacitor C1) to rise as well. However, a rising voltage at node Nd4will be inverted by inverter I1thereby causing node Nd3to not rise from the ESD event at node Nd2causing NMOS transistors N1and N2to not turn on, and NMOS transistors N1and N2have a minimal effect on an ESD event at node Nd2. Other configurations or quantities of circuits in integrated circuit400are within the scope of the present disclosure. FIG.5is a flowchart of a method500of operating an ESD circuit, in accordance with some embodiments. In some embodiments, the circuit of method500includes at least integrated circuit100,200or300A-300B (FIG.1,2or3A-3B). It is understood that additional operations may be performed before, during, and/or after the method500depicted inFIG.5, and that some other processes may only be briefly described herein. It is understood that method500utilizes features of one or more of integrated circuit100,200or300A-300B. Method500is applicable to at least integrated circuit300A or300B. Method500is initially described with respect to integrated circuit300A and current path I2. However, method500is also applicable to integrated circuit300B and current path I1, and is described below after the description of integrated circuit300A. Other order of operations of method500to integrated circuit300A or300B is within the scope of the present disclosure. At operation502of method500, an ESD voltage of an ESD event is received on a first node. In some embodiments, the ESD voltage is greater than a supply voltage VDD of a voltage supply. In some embodiments, the first node of method500includes node Nd3. In some embodiments, the first node of method500includes at least JO pad108, conductive structure340or conductive structure342. At operation504, a diode is turned on, thereby conducting an ESD current from an anode of the diode to a cathode of the diode. In some embodiments, the diode of method500includes at least diode D1or302. In some embodiments, the anode of method500includes at least the anode of diode D1or anode302a. In some embodiments, the cathode of method500includes at least the cathode of diode D1, cathode302cor302d. In some embodiments, the ESD current of method500includes current I2. At operation506, the ESD current is conducted from the cathode of the diode to a first signal tap of a clamp circuit. In some embodiments, the first signal tap of method500includes at least signal tap250or350. In some embodiments, the clamp circuit of method500includes at least ESD clamp circuit120,220, or310. At operation508, the ESD current of the ESD event is discharged by the ESD clamp circuit. In some embodiments, the ESD current of the ESD event is discharged by a channel of a first transistor or a channel of a second transistor. In some embodiments, the first transistor of method500includes NMOS transistor N1, and the channel includes channel region310d. In some embodiments, the second transistor of method500includes NMOS transistor N2, and the channel includes channel region312d. In some embodiments, operation508includes at least operation510,512,514or516. At operation510, the ESD clamp circuit is turned on in response to the ESD current being received at the first signal tap of the ESD clamp circuit or a second node. In some embodiments, the second node of method500includes node Nd1. In some embodiments, the second node of method500corresponds to conductive structure390. At operation512, the second node is coupled to a third node in response to the ESD clamp circuit turning on. In some embodiments, the third node of method500includes node Nd2. In some embodiments, the third node of method500corresponds to conductive structure392. In some embodiments, the second node is coupled to the third node in response to the NMOS transistor N1and NMOS transistor N2of ESD clamp circuit turning on. At operation514, the ESD current is conducted from the first signal tap or the second node to a second signal tap of the ESD clamp circuit. In some embodiments, the second signal tap of method500includes at least signal tap252or352. At operation516, the ESD current is conducted from the second signal tap of the clamp circuit to a fourth node. In some embodiments, the fourth node of method500includes at least reference voltage supply node106(e.g., voltage VSS) or conductive structure346. While method500was described with respect to integrated circuit300A and current path I2, method500is also applicable to integrated circuit300B and current path I1and is described below with similar operations. For example, at operation502, the ESD voltage of the ESD event is received on the first node. In some embodiments, the ESD voltage is greater than a reference supply voltage VSS of reference voltage supply node106. In some embodiments, the first node of method500includes at least IO pad108or conductive structure342. At operation504, the diode is turned on, thereby conducting the ESD current from the anode of the diode to the cathode of the diode. In some embodiments, the diode of method500includes at least diode D2or304. In some embodiments, the anode of method500includes at least the anode of diode D2or anode304a. In some embodiments, the cathode of method500includes at least the cathode of diode D2, cathode304cor304d. In some embodiments, the ESD current of method500includes current I1. At operation506, the ESD current is conducted from the cathode of the diode to the first signal tap of the clamp circuit. In some embodiments, the first signal tap of method500includes at least signal tap252or352. At operation508, the ESD current of the ESD event is discharged by the ESD clamp circuit. In some embodiments, the SD current of the ESD event is discharged by channel region312dof NMOS transistor N2and channel region310dof NMOS transistor N1. At operation510, the ESD clamp circuit is turned on in response to the ESD current being received at the first signal tap of the ESD clamp circuit or the second node. In some embodiments, the second node of method500includes node Nd2. In some embodiments, the second node of method500corresponds to conductive structure392. At operation512, the second node is coupled to the third node in response to the ESD clamp circuit turning on. In some embodiments, the third node of method500includes node Nd1. In some embodiments, the third node of method500corresponds to conductive structure390. In some embodiments, the second node is coupled to the third node in response to the NMOS transistor N1and NMOS transistor N2of ESD clamp circuit turning on. At operation514, the ESD current is conducted from the first signal tap or the second node to the second signal tap of the ESD clamp circuit. In some embodiments, the second signal tap of method500includes at least signal tap250or350. At operation516, the ESD current is conducted from the second signal tap of the clamp circuit to the fourth node. In some embodiments, the fourth node of method500includes at least voltage supply node104(e.g., voltage VDD) or conductive structure344. In some embodiments, one or more of the operations of method500is not performed. In some embodiments, one or more of the operations of method500is repeated. In some embodiments, method500is repeated. FIG.6is a flow chart of a method of manufacturing an integrated circuit, in accordance with some embodiments. In some embodiments, the method600is usable to manufacture or fabricate at least integrated circuit100,200or300A-300B (FIG.1,2or3A-3B). It is understood that additional operations may be performed before, during, and/or after the method600depicted inFIG.6, and that some other processes may only be briefly described herein. It is understood that method600utilizes features of one or more of integrated circuit100,200or300A-300B. Method600is applicable to at least integrated circuit300A or300B. Method600is described with respect to integrated circuit300A. However, method600is also applicable to integrated circuit300B. Other order of operations of method600to integrated circuit300A or300B is within the scope of the present disclosure. In operation602of method600, a first diode is fabricated on a front-side of a wafer. In some embodiments, the wafer of method600includes substrate320. In some embodiments, the front-side of the wafer of method600includes at least front-side305of substrate320. In some embodiments, the first diode of method600includes at least diode302. In some embodiments, operation602includes at least operation602aor602b. In some embodiments, operation602aincludes depositing an oxide layer704(FIGS.7A-7E) on the front-side305of substrate320and is shown inFIG.7A. In some embodiments, operation602bincludes forming an opening in the oxide layer704, and then filling the opening in the oxide layer with a conductive material thereby forming a via706(FIG.7B), and growing an epitaxial layer708(FIG.7B) in an unfilled portion of the opening and is shown inFIG.7B. In some embodiments, the epitaxial layer708(FIG.7B) corresponds to cathode region302cand302d. In some embodiments, operation602further includes fabricating well322in substrate320, fabricating a heavily doped region324in well322thereby forming anode region302aof the first diode, fabricating cathode region302cand302din well322, and fabricating gate structure302b. In some embodiments, at least well322, well360or362(e.g., ESD clamp circuit310) comprises p-type dopants. In some embodiments, the p-dopants include boron, aluminum or other suitable p-type dopants. In some embodiments, at least well322, well360or362comprises an epi-layer grown over substrate320. In some embodiments, the epi-layer is doped by adding dopants during the epitaxial process. In some embodiments, the epi-layer is doped by ion implantation after the epi-layer is formed. In some embodiments, at least well322, well360or362is formed by doping substrate320. In some embodiments, the doping is performed by ion implantation. In some embodiments, at least well322, well360or362has a dopant concentration ranging from 1×1012atoms/cm3to 1×1014atoms/cm3. In some embodiments, region324is formed by a process similar to the formation of well322. In some embodiments, region324is a heavily doped p-region. In some embodiments, at least fabricating cathode regions302cand302dof operation602or fabricating cathode regions304cand304dof operation604(described below) includes the formation of cathode features in the substrate. In some embodiments, the formation of the cathode features includes removing a portion of the substrate to form recesses at an edge of well322or332, and a filling process is then performed by filling the recesses in the substrate. In some embodiments, the recesses are etched, for example, by a wet etching or a dry etching, after removal of a pad oxide layer or a sacrificial oxide layer. In some embodiments, the etch process is performed to remove a top surface portion of the active region adjacent to an isolation region, such as STI region328a,328b,328cor328d. In some embodiments, the filling process is performed by an epitaxy or epitaxial (epi) process. In some embodiments, the recesses are filled using a growth process which is concurrent with an etch process where a growth rate of the growth process is greater than an etch rate of the etch process. In some embodiments, the recesses are filled using a combination of growth process and etch process. For example, a layer of material is grown in the recess and then the grown material is subjected to an etch process to remove a portion of the material. Then a subsequent growth process is performed on the etched material until a desired thickness of the material in the recess is achieved. In some embodiments, the growth process continues until a top surface of the material is above the top surface of the substrate. In some embodiments, the growth process is continued until the top surface of the material is co-planar with the top surface of the substrate. In some embodiments, a portion of well322or332is removed by an isotropic or an anisotropic etch process. The etch process selectively etches well322or332without etching gate structure302bor304b. In some embodiments, the etch process is performed using a reactive ion etch (RIE), wet etching, or other suitable techniques. In some embodiments, a semiconductor material is deposited in the recesses to form the cathode features similar to source/drain features. In some embodiments, an epi process is performed to deposit the semiconductor material in the recesses. In some embodiments, the epi process includes a selective epitaxy growth (SEG) process, CVD process, molecular beam epitaxy (MBE), other suitable processes, and/or combination thereof. The epi process uses gaseous and/or liquid precursors, which interacts with a composition of substrate320. In some embodiments, the cathode features include epitaxially grown silicon (epi Si), silicon carbide, or silicon germanium. Cathode features of the IC device associated with gate structure302bor304bare in-situ doped or undoped during the epi process in some instances. When cathode features are undoped during the epi process, cathode features are doped during a subsequent process in some instances. The subsequent doping process is achieved by an ion implantation, plasma immersion ion implantation, gas and/or solid source diffusion, other suitable processes, and/or combination thereof. In some embodiments, cathode features are further exposed to annealing processes after forming cathode features and/or after the subsequent doping process. In some embodiments, at least fabricating the gate regions of operation602,604or606(described below) includes performing one or more deposition processes to form one or more dielectric material layers. In some embodiments, a deposition process includes a chemical vapor deposition (CVD), a plasma enhanced CVD (PECVD), an atomic layer deposition (ALD), or other process suitable for depositing one or more material layers. In some embodiments, fabricating the gate regions includes performing one or more deposition processes to form one or more conductive material layers. In some embodiments, fabricating the gate regions includes forming gate electrodes or dummy gate electrodes. In some embodiments, fabricating the gate regions includes depositing or growing at least one dielectric layer, e.g., gate dielectric. In some embodiments, gate regions are formed using a doped or non-doped polycrystalline silicon (or polysilicon). In some embodiments, the gate regions include a metal, such as Al, Cu, W, Ti, Ta, TiN, TaN, NiSi, CoSi, other suitable conductive materials, or combinations thereof. In operation604of method600, a second diode is fabricated on the front-side of the wafer. In some embodiments, the back-side of the wafer of method600includes at least back-side303of substrate320. In some embodiments, the second diode of method600includes at least diode304. In some embodiments, operation604includes at least operation604aor604b. In some embodiments, operation604aincludes depositing oxide layer704(FIGS.7A-7E) on the front-side305of substrate320and is shown inFIG.7A. In some embodiments, operation604bincludes forming an opening in the oxide layer704, and then filling the opening in the oxide layer with a conductive material thereby forming a via706(FIG.7B), and growing an epitaxial layer708(FIG.7B) is grown in an unfilled portion of the opening and is shown inFIG.7B. In some embodiments, the epitaxial layer708(FIG.7B) corresponds to cathode region304cand304d. In some embodiments, operation604further includes fabricating well332in substrate320, fabricating a heavily doped region334in well332thereby forming anode region304aof the second diode, fabricating cathode region304cand304dabove well332, and fabricating gate structure304b. In some embodiments, well332comprises n-type dopants. In some embodiments, the n-type dopants include phosphorus, arsenic or other suitable n-type dopants. In some embodiments, the n-type dopant concentration ranges from about 1×1012atoms/cm3to about 1×1014atoms/cm3. In some embodiments, well332is formed by ion implantation. The power of the ion implantation ranges from about 1500 k electron volts (eV) to about 8000 k eV. In some embodiments, well332is epitaxially grown. In some embodiments, well332comprises an epi-layer grown over the surface. In some embodiments, the epi-layer is doped by adding dopants during the epitaxial process. In some embodiments, the epi-layer is doped by ion implantation after the epi-layer is formed, and has the dopant concentration described above. In some embodiments, region334is formed by a process similar to the formation of well332. In some embodiments, region334is a heavily doped n-region. In operation606of method600, an ESD clamp circuit is fabricated on the front-side of the wafer. In some embodiments, the ESD clamp circuit of method600includes at least ESD clamp circuit310. In some embodiments, operation606includes at least operation606aor606b. In some embodiments, operation606aincludes depositing oxide layer704(FIGS.7A-7E) on the front-side305of substrate320and is shown inFIG.7A. In some embodiments, operation606bincludes forming an opening in the oxide layer704, and then filling the opening in the oxide layer with a conductive material thereby forming a via706(FIG.7B), and growing an epitaxial layer708(FIG.7B) in an unfilled portion of the opening and is shown inFIG.7B. In some embodiments, the epitaxial layer708(FIG.7B) corresponds to source310cor312cand drain310aor312a. In some embodiments, operation606further includes fabricating wells360and362in substrate320, fabricating source/drain regions (e.g., source310cand drain310a) in well360, and fabricating source/drain regions (e.g., source312cand drain312a) in well362, and fabricating gate structures310band312b. In some embodiments, fabricating source/drain regions (e.g., source310cand drain310a) in well360of operation606includes operation608. In some embodiments, fabricating source/drain regions (e.g., source312cand drain312a) in well362of operation606, and fabricating gate structures310band312bincludes operation610. In operation608of method600, a first signal tap region is fabricated on the front-side of the wafer. In some embodiments, the first signal tap region of method600includes at least signal tap region350. In some embodiments, signal tap region350corresponds to drain310aof ESD clamp circuit310. In some embodiments, operation608corresponds to operation606b. In operation610of method600, a second signal tap is fabricated on the front-side of the wafer. In some embodiments, the second signal tap region of method600includes at least signal tap region352. In some embodiments, signal tap region352corresponds to source312cof ESD clamp circuit310. In some embodiments, operation608corresponds to operation606b. In some embodiments, at least signal tap region350or352comprises p-type dopants. In some embodiments, the p-dopants include boron, aluminum or other suitable p-type dopants. In some embodiments, at least signal tap region350or352is formed by a process similar to the formation of corresponding well360or362. In some embodiments, at least signal tap region350or352is a heavily doped p-region. In some embodiments, at least signal tap region350or352comprises n-type dopants. In some embodiments, the n-type dopants include phosphorus, arsenic or other suitable n-type dopants. In some embodiments, the n-type dopant concentration ranges from about 1×1012atoms/cm2 to about 1×1014atoms/cm2. In some embodiments, at least signal tap region350or352is formed by ion implantation. The power of the ion implantation ranges from about 1500 k electron volts (eV) to about 8000 k eV. In some embodiments, at least signal tap region350or352is a heavily doped n-region. In some embodiments, at least signal tap region350or352is epitaxially grown. In some embodiments, at least signal tap region350or352comprises an epi-layer grown over substrate320. In some embodiments, the epi-layer is doped by adding dopants during the epitaxial process. In some embodiments, the epi-layer is doped by ion implantation after the epi-layer is formed. In some embodiments, at least signal tap region350or352is formed by doping substrate320. In some embodiments, the doping is performed by ion implantation. In some embodiments, at least signal tap region350or352has a dopant concentration ranging from 1×1012atoms/cm3 to 1×1014atoms/cm3. In operation612of method600, a first set of conductive structures710(FIG.7C) is fabricated on the front-side305of the wafer320.FIG.7Cis a cross-sectional view of the first set of conductive structures710fabricated on the front-side305of the wafer320following at least operation612, in accordance with one or more embodiments. In some embodiments, operation612includes depositing the first set of conductive structures710on the front-side305of the wafer320. In some embodiments, the first set of conductive structures710of method600includes at least conductive structure390and conductive structure392. In some embodiments, operation612includes depositing an insulating layer712(FIG.7C) on the front-side305of the wafer320, removing portions of the insulating layer712from the front-side305of the wafer320, and depositing the first set of conductive structures710in the removed portions of the insulating layer712on the front-side305of the wafer320. In some embodiments, the first set of conductive structures of method600are formed using a combination of photolithography and material removal processes to form openings in an insulating layer (not shown) over the substrate. In some embodiments, the photolithography process includes patterning a photoresist, such as a positive photoresist or a negative photoresist. In some embodiments, the photolithography process includes forming a hard mask, an antireflective structure, or another suitable photolithography structure. In some embodiments, the material removal process includes a wet etching process, a dry etching process, an RIE process, laser drilling or another suitable etching process. The openings are then filled with conductive material, e.g., copper, aluminum, titanium, nickel, tungsten, or other suitable conductive material. In some embodiments, the openings are filled using CVD, PVD, sputtering, ALD or other suitable formation process. In operation614of method600, wafer thinning is performed on the back-side303of the wafer.FIG.7Dis a cross-sectional view of the wafer320prior to the wafer thinning of operation614, in accordance with one or more embodiments. In some embodiments, operation614includes flipping the wafer320over, and performing a thinning process on the back-side303of the semiconductor wafer or substrate. In some embodiments, the thinning process includes a grinding operation and a polishing operation (such as chemical mechanical polishing (CMP)) or other suitable processes. In some embodiments, after the thinning process, a wet etching operation is performed to remove defects formed on the backside303of the semiconductor wafer320or substrate. In operation616of method600, an insulating layer722(FIG.7E) is deposited on the back-side of the wafer. In some embodiments, the insulating layer722of method600includes insulating layer321. In some embodiments, the insulating layer321includes a dielectric material including oxide or another suitable insulating material. In some embodiments, the insulating layer321is formed by CVD, spin-on polymeric dielectric, atomic layer deposition (ALD), or other processes. In operation618of method600, portions of the insulating layer722are removed from the back-side of the wafer. In some embodiments, operation618of method600uses a combination of photolithography and material removal processes to form openings in an insulating layer722over the wafer320. In some embodiments, the photolithography process includes patterning a photoresist, such as a positive photoresist or a negative photoresist. In some embodiments, the photolithography process includes forming a hard mask, an antireflective structure, or another suitable photolithography structure. In some embodiments, the material removal process includes a wet etching process, a dry etching process, an RIE process, laser drilling or another suitable etching process. In operation620of method600, a second set of conductive structures720(FIG.7E) is deposited in at least the removed portion of the insulating layer.FIG.7Eis a cross-sectional view of the wafer320following at least operation620, in accordance with one or more embodiments. In some embodiments, operation620includes depositing the second set of conductive structures720on the back-side of the wafer. In some embodiments, the second set of conductive structures720of method600includes at least conductive structure340, conductive structure342, conductive structure344or conductive structure346. In some embodiments, operation620includes filling the openings in the insulating layer722with conductive material, e.g., copper, aluminum, titanium, nickel, tungsten, or other suitable conductive material. In some embodiments, the openings are filled using CVD, PVD, sputtering, ALD or other suitable formation process. In some embodiments, one or more of the operations of method600is not performed. In some embodiments, one or more of the operations of method600is repeated. In some embodiments, method600is repeated. FIGS.7A-7Eare cross-sectional views of an integrated circuit, in accordance with one or more embodiments. FIG.7Ais a cross-sectional view of an integrated circuit700A, in accordance with one or more embodiments. In some embodiments, integrated circuit700A corresponds to an integrated circuit, such as integrated circuit300A or300B, following at least operation602a,604aor606a. In some embodiments, integrated circuit700A includes an oxide layer704on substrate320. FIG.7Bis a cross-sectional view of an integrated circuit700B, in accordance with one or more embodiments. In some embodiments, integrated circuit700B corresponds to an integrated circuit, such as integrated circuit300A or300B, following at least operation602b,604bor606b. In some embodiments, integrated circuit700B includes via706formed in an opening of at least the oxide layer704or the substrate320. In some embodiments, integrated circuit700B further includes an epitaxial layer708over via706, the oxide layer704and the substrate320. In some embodiments, the epitaxial layer708is grown in an unfilled portion of the opening of the oxide layer704. FIG.7Cis a cross-sectional view of an integrated circuit700C, in accordance with one or more embodiments. In some embodiments, integrated circuit700C corresponds to an integrated circuit, such as integrated circuit300A or300B, following at least operation612. In some embodiments, integrated circuit700C includes the first set of conductive structures710, insulating layer712and integrated circuit700B. In some embodiments, integrated circuit700C includes the first set of conductive structures710fabricated in removed portions of insulating layer712on the front-side305of the wafer320. FIG.7Dis a cross-sectional view of an integrated circuit700D, in accordance with one or more embodiments. In some embodiments, integrated circuit700D corresponds to an integrated circuit, such as integrated circuit300A or300B, prior to the wafer thinning of operation614. In some embodiments, integrated circuit700D includes integrated circuit700C flipped over. FIG.7Eis a cross-sectional view of an integrated circuit700E, in accordance with one or more embodiments. In some embodiments, integrated circuit700E corresponds to an integrated circuit, such as integrated circuit300A or300B, following at least operation620. In some embodiments, integrated circuit700E includes the second set of conductive structures720, insulating layer722and integrated circuit700D (without the removed portion of wafer320). In some embodiments, integrated circuit700E includes the second set of conductive structures720fabricated in removed portions of insulating layer722of the wafer320. Other diode types or numbers of diodes, or other transistor types or other numbers of transistors in at least integrated circuit100,200and300A-300B of correspondingFIGS.1,2and3A-3Bare within the scope of the present disclosure. Furthermore, various NMOS or PMOS transistors shown inFIGS.3A-3Bare of a particular dopant type (e.g., N-type or P-type) and are for illustration purposes. Embodiments of the disclosure are not limited to a particular transistor type, and one or more of the PMOS or NMOS transistors shown inFIGS.3A-3Bcan be substituted with a corresponding transistor of a different transistor/dopant type. Similarly, the low or high logical value of various signals used in the above description is also used for illustration. Embodiments of the disclosure are not limited to a particular logical value when a signal is activated and/or deactivated. Selecting different logical values is within the scope of various embodiments. Selecting different numbers of PMOS transistors in3A-3B is within the scope of various embodiments. One aspect of this description relates to an ESD protection circuit. The ESD protection circuit includes a first diode in a semiconductor wafer, and being coupled between an input output (IO) pad and a first node. In some embodiments, the ESD protection circuit further includes a second diode in the semiconductor wafer, and being coupled to the first diode and, being coupled between the IO pad and a second node. In some embodiments, the ESD protection circuit further includes an ESD clamp circuit in the semiconductor wafer, being coupled between the first node and the second node, and being further coupled to the first diode and the second diode. In some embodiments, the ESD clamp circuit includes a first signal tap region in the semiconductor wafer. In some embodiments, the first signal tap region being coupled to a first voltage supply. In some embodiments, the first diode being coupled to and configured to share the first signal tap region with the ESD clamp circuit. In some embodiments, the ESD protection circuit further includes a first conductive structure on a backside of the semiconductor wafer, and being coupled to at least the first voltage supply. Another aspect of this description relates to an ESD protection circuit. The ESD protection circuit includes a first diode in a semiconductor wafer, and being coupled to a first pad. In some embodiments, the ESD protection circuit further includes a second diode in the semiconductor wafer, and being coupled to the first diode and the first pad. In some embodiments, the ESD protection circuit further includes an input output (IO) circuit in the semiconductor wafer, being coupled to the first diode, the second diode, and the first pad. In some embodiments, the ESD protection circuit further includes an internal circuit coupled to the IO circuit. In some embodiments, the ESD protection circuit further includes an ESD clamp circuit in the semiconductor wafer, coupled to the first diode by a first node and coupled to the second diode by a second node. In some embodiments, the ESD clamp circuit includes a first signal tap region coupled to a voltage supply, and a second signal tap region coupled to a reference voltage supply. In some embodiments, the first diode is coupled to and configured to share the first signal tap region with the ESD clamp circuit. In some embodiments, the second diode is coupled to and configured to share the second signal tap region with the ESD clamp circuit. Yet another aspect of this description relates to a method of operating an ESD protection circuit. The method includes receiving a first ESD voltage on a first node, the first ESD voltage being greater than a supply voltage of a voltage supply, the first ESD voltage corresponding to a first ESD event. In some embodiments, the method further includes turning on a first diode thereby conducting a first ESD current from a first anode of the first diode to a first cathode of the first diode. In some embodiments, the method further includes conducting the first ESD current from the first cathode of the first diode to a first signal tap of an ESD clamp circuit, wherein the ESD clamp circuit is coupled to the first diode, the first signal tap is coupled to the voltage supply, and the first diode is coupled to and configured to share the first signal tap with the ESD clamp circuit. In some embodiments, the method further includes turning on the ESD clamp circuit in response to the first ESD current being received at the first signal tap of the ESD clamp circuit or a second node. In some embodiments, the method further includes discharging the first ESD current of the first ESD event by the ESD clamp circuit. A number of embodiments have been described. It will nevertheless be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, various transistors being shown as a particular dopant type (e.g., N-type or P-type Metal Oxide Semiconductor (NMOS or PMOS)) are for illustration purposes. Embodiments of the disclosure are not limited to a particular type. Selecting different dopant types for a particular transistor is within the scope of various embodiments. The low or high logical value of various signals used in the above description is also for illustration. Various embodiments are not limited to a particular logical value when a signal is activated and/or deactivated. Selecting different logical values is within the scope of various embodiments. In various embodiments, a transistor functions as a switch. A switching circuit used in place of a transistor is within the scope of various embodiments. In various embodiments, a source of a transistor can be configured as a drain, and a drain can be configured as a source. As such, the term source and drain are used interchangeably. Various signals are generated by corresponding circuits, but, for simplicity, the circuits are not shown. Various figures show capacitive circuits using discrete capacitors for illustration. Equivalent circuitry may be used. For example, a capacitive device, circuitry or network (e.g., a combination of capacitors, capacitive elements, devices, circuitry, or the like) can be used in place of the discrete capacitor. The above illustrations include exemplary steps, but the steps are not necessarily performed in the order shown. Steps may be added, replaced, changed order, and/or eliminated as appropriate, in accordance with the spirit and scope of disclosed embodiments. The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. | 91,251 |
11862961 | Like references are used to designate equivalent or at least functionally equivalent parts in the accompanying drawings. DETAILED DESCRIPTION The detailed description provided below in connection with the appended drawings is intended as a description of the embodiments and is not intended to represent the only forms in which the embodiment may be constructed or utilized. However, the same or equivalent functions and structures may be accomplished by different embodiments. FIG.1shows an example of an electric power network system100(below also “the network system”). The network system100may be part of an electrical grid, e.g. a national or a regional grid, for delivering electricity from producers to consumers. The network system100may comprise a transmission network and/or a distribution network. The network system100may comprise a first network110, such as a high-voltage network or a transmission network. In addition, the network system100may comprise a second network112, such as a medium-voltage network, a distribution network or a low-voltage network. The network system100may further comprise a transformer120, such as a substation primary transformer, for lowering the voltage from the first network110and/or to the second network112. The second network112may be connected to the first network region110through the transformer120. In the following, earth-fault compensation is illustrated in the second network112(below also “the network”). However, it should be understood that the present invention may be used wherever an arc suppression coil, or a Petersen coil, is used. The network112may be an alternating current network, such as a three-phase network. The network112may have an operating frequency, e.g. 50-60 Hz, which may be constant. The network112comprises an arrangement150(below also “the arrangement”) which may be adapted for earth fault compensation in the network112, so that the network112is a compensated network. The arrangement150may be adapted to be located at an electrical substation, such as at the substation between a transmission network and a distribution network. However, the arrangement150may also be adapted to be located together with a distribution transformer, in which case the arrangement150may be adapted for distributed earth fault compensation. Consequently, the arrangement150may be used, for example, not only where high-voltage is converted to medium-voltage but, alternatively or additionally, where medium-voltage is converted to low-voltage. The arrangement150comprises one or more arc suppression coils, adapted to compensate capacitive reactance of the network112during an earth fault. The inductive reactance of the one or more arc suppression coils may substantially correspond to the inductive reactance of the network112so that the inductive reactance of the network112is substantially due to the one or more arc suppression coils. The arrangement150may be directly connected to earth, i.e. to the ground of the network112. The arrangement150may, at least partially, comprise an apparatus, such as a controller, for operating the network112. However, it is noted that the apparatus may also be comprised in a distributed system for controlling the electric power network112. The electric power network112may comprise one or more feeders140, e.g. distribution network feeders, for feeding electricity forward in the network112. A feeder140may be an overhead feeder or an underground feeder. A feeder140may comprise one or more power lines. For example, in a three-phase network a feeder140may comprise three power lines, one for each phase. A feeder140may be protected by one or more relays142, i.e. protective relays, which may adapted to disconnect the one or more power lines of the feeder140during a fault, such as an earth fault. Consequently, the fault current corresponding to an earth fault may be removed by tripping one or more of the one or more relays142. The one or more relays142may be adapted for independent operation, for example in that they measure current and/or voltage in one or more power lines of the feeder140and disconnect the one or more power lines under specified conditions. These measurements may be local, i.e. at the feeder140. A relay142can be adapted to disconnect one or more power lines, e.g. by opening its own breaker, if it finds a fault condition. The one or more relays142may comprise a microprocessor. While the relays142may be adapted for various types of fault situations, it is noted that in typical networks the functioning and reliability of the relays142may be affected by their operating conditions. The apparatus for operating the network112may be adapted to control the one or more arc suppression coils. The apparatus may also be adapted to indirectly control the tripping of the one or more relays142by altering the zero sequence voltage of the network112. The electric power network112may comprise a bus130such as a substation bus. The bus130may be a medium-voltage bus. The bus130may be arranged to connect the arrangement150to the one or more feeders140. Alternatively or additionally, the bus130may be arranged to connect the arrangement150to the transformer120. The arrangement150may be used to provide earth fault compensation to a plurality of feeders140. An earth fault may take place when a power line of a feeder140comes into electric contact with the earth. In principle, a fault location144may be at any point along the length of the feeder140, which may have a length of several kilometers. FIG.2shows an example of operating an electric power network112, which can be the network112described above, e.g. by the apparatus described above. Operating the network112comprises operating an arc suppression coil in the network112. In normal operation200, the arc suppression coil may be operated on-resonance or off-resonance with respect to a normal state resonance point of the network112. The first alternative means that the inductance of the arc suppression coil is adjusted so that the magnitude of the inductive reactance of the network112is substantially equal to the magnitude of the capacitive reactance of the network112, whereas the latter alternative means that the magnitudes of the inductive and the capacitive reactance are substantially different from each other. The arc suppression coil may be operated off-resonance by 5-20 percent, when calculated from the total capacitance of the network112, e.g. from the line-to-earth capacitance. However, the present disclosure allows even larger values, for example up to 50-70 percent. Increasing the departure from resonance allows reducing the zero sequence voltage of the network112, which may in turn reduce power losses in the network112. Operating the arc suppression coil on-resonance or close to the normal state resonance point allows reducing any initial fault current in the occurrence of an earth fault. Normal operation200of the network112is interrupted by the occurrence of an earth fault202in the network112. As a result, a fault current will flow at the fault location144between the faulty feeder140and the earth. Since the arc suppression coil is operated off-resonance, the fault current, which may be over 10 A, e.g. 15-20 A, has both a resistive component and a reactive component, the latter of which may be for example 7-15 A. In response to the earth fault, an indication is received, e.g. by the apparatus, for the occurrence of the earth fault. The occurrence may be determined, for example, based on an increase in a zero sequence voltage of the network112or an indication thereof and/or an increase in the negative sequence current of the network112or an indication thereof. This determination may be based on one or more measurements of current and/or voltage. The measurements may be local, e.g. at a bus130such as a substation bus directly connected to the arrangement150for earth fault compensation. After the indication for the occurrence of the earth fault has been received, the tuning of the arc suppression coil may be changed210, e.g. by the apparatus. Importantly, the tuning may be changed while the earth fault is present in the network112. Tuning the arc suppression coil towards resonance reduces the reactive component of the fault current, thereby reducing the total fault current. This may markedly improve the probability of extinguishing the fault arc, thereby removing the earth fault. Moreover, it allows reducing the risk of damage from dangerously high contact voltage. The arc suppression coil may be tuned directly or sequentially to resonance with respect to the normal state resonance point in an attempt to remove the earth fault. Alternatively or additionally, it is possible to determine a fault state resonance point of the network112or a value indicative thereof, while the earth fault is present in the network112, and tune the arc suppression coil to resonance with respect to this fault state resonance point. This may allow even further reduction in the fault current, when the fault state resonance point has shifted substantially from the normal state resonance point. In typical real-world networks, the fault state resonance point remains close or substantially at the normal state resonance point. This means that any initial change in tuning towards the normal state resonance point corresponds also to a change in tuning towards the fault state resonance point. An initial change in tuning towards the fault state resonance point, which equals a change in tuning towards the normal state resonance point, can therefore be made already before the fault state resonance point or a value indicative thereof has been determined. This allows quick reaction to the occurrence of the earth fault as the tuning may be changed in milliseconds or even less. Naturally, the determination for the fault state resonance point may also be performed before any change in tuning. The change in tuning can be considered as entering into a tracking mode212for attempting to extinguish the fault arc. If the attempt to extinguish the fault arc is successful, the arc suppression coil may be returned214to off-resonance for normal operation200of the network112. The disappearance of the earth fault may be determined based on a decrease in the zero sequence voltage of the network112or an indication thereof and/or on a decrease in the negative sequence current of the network112or an indication thereof. However, the arc suppression coil may also be tuned away from resonance so that the fault current increases. This increase in fault current can be visible to the one or more relays142, which may adapted to trip under conditions indicative of an excessive fault current. This allows using the tuning of the arc suppression coil to trip220the one or more relays142, which in turn allows controllable tripping of the one or more relays142. The tripping220can be performed in response to receiving the indication for the occurrence of the earth fault. It can be performed with or without delay after receiving the indication for the occurrence of the earth fault. For example, the arc suppression coil may be tuned away from resonance to trip220the one or more relays immediately or after a threshold time from the receipt of the indication for the presence of the earth fault. It is also possible to first try attempt to extinguish the fault arc, for example by tuning the arc suppression coil to resonance with respect to a resonance point such as a fault state resonance point of the network112, e.g. by entering into a tracking mode. If, after one or more changes in tuning of the arc suppression coil, the attempt to extinguish the fault arc has not been successful, the arc suppression coil may be tuned away from resonance to trip220the one or more relays142in the network112to disconnect one or more power lines in the feeder140where the earth fault is present. Tuning the arc suppression coil away from resonance to trip220the one or more relays allows the network112and its surroundings to be protected as the fault current can be removed, thereby extinguishing also the fault arc. The tripping220may be performed after a threshold time has passed from the occurrence of the earth fault202, or the receipt of an indication thereof. The threshold time may be as small as, for example, 100-1000 milliseconds but it can also be larger, if appropriate. In particular, the threshold time may be dependent on the magnitude of the fault current so that for small enough levels of fault current it may be even infinite. While such a threshold time may be configured in the relays142, a potential suppression of the fault current during the tracking mode means that the relays142may not necessarily have the correct information regarding the conditions of the earth fault, such as the actual time of occurrence of the earth fault. However, changing the tuning of the arc suppression coil allows flexibly triggering one or more relays142even when they are configured to function independently. The threshold time may also be determined based on one or more regulations pertaining to operation of the network112, allowing flexible compliance with different regulatory regimes. The algorithms of protective relays have typically troubles with low current levels so that tripping the relays by tuning the arc suppression coil allows improved control of the relay operation as well. Moreover, this control can be centralized, e.g. in the apparatus for operating the network112. The control over the one or more relays142is indirect as it takes place by changing the current and/or voltage the one or more relays142are adapted to measure. Indirect control of the relays in the presence of an earth fault can be particularly effective when the arc suppression coil is tuned by adjusting the reluctance of the arc suppression coil, in particular by adjusting the magnitude of a virtual air gap of the arc suppression coil. These methods allow continuous control of the inductance of the arc suppression coil. They may also be operated without generating additional harmonics strengthening the fault arc. Once one or more relays142have been tripped, fault location, isolation and removal (FLIR) operations may be performed222to remove the earth fault. Once the earth fault has been removed, the arc suppression coil may be returned224to off-resonance for normal operation200of the network112. FIG.3aillustrates a general arrangement300for earth fault compensation. The arc suppression coil is operated in the network112, which can be a three-phase network. The general arrangement300comprises an arc suppression coil310adapted to compensate earth faults in the network112. In addition, the general arrangement300comprises an earthing transformer320through which the arc suppression coil320is connected to other parts of the network112, e.g. through the bus130. The general arrangement300is grounded to the earth340and the grounding connection may be made directly from the arc suppression coil310, which is typically mechanically operated, for example so that a motor inside a transformer moves a metallic component, and cannot be adjusted during an earth fault. Consequently, a general arrangement300often comprises means330such as an oil-immersed high-power resistor together with a switch, which may be used during an earth fault to connect the resistor in parallel with the arc suppression coil310. The arrangement150of the present disclosure may be formed in accordance with the general arrangement but with the arc suppression coil being adapted for its inductance to be adjustable during the presence of an earth fault. FIG.3billustrates an arrangement150for earth fault compensation according to an example. While the present disclosure may be used also with a regular arc suppression coil310, such as the one disclosed above, together with means such as inverter, this particle example is illustrated as it allows particularly flexible operation of the arc suppression coil when an earth fault is present in the network112. In the example, the arc suppression coil312is operated in the network112, which can be a three-phase network. The arrangement150comprises an arc suppression coil312adapted to compensate earth faults in the network112. Importantly, the arc suppression coil312is adapted for its inductance to be adjusted while an earth fault is present in the network112. It is therefore enough to use a single arc suppression coil312having an adjustable inductance but naturally the arrangement may also comprise one or more additional arc suppression coils. The arc suppression coil312may even be formed as one monolithic structure functioning both as an earthing transformer and an inductive compensator for the capacitive reactance of the network112. The inductance may be adjusted by adjusting the reluctance of the arc suppression coil312, for example by adjusting the size of a virtual air gap314of the arc suppression coil. No separate earthing transformers and/or parallel resistors are needed, which may allow reduction in both cost and size of the arrangement150. The inductance may be adjusted electrically, allowing notable increase in speed in comparison to mechanical adjustment means. The arc suppression coil320may be directly connected to other parts of the network112, for example directly to the bus130. The arrangement150is grounded to the earth340and the grounding connection may be made directly from the arc suppression coil312. In the absence of the earthing transformer, the arrangement150can be made without a star point, at least as a physical point. Correspondingly, the star point of the arrangement150may be a virtual star point. The zero sequence voltage for the network112or a value indicative thereof may be determined by calculation, e.g. as an average of measured phase voltages350,352,354. The arrangement150can be made with substantially negligible DC (direct current) resistance. The arrangement150may comprise means, such as an actuator, for forming a virtual air gap314in the arc suppression312for adjusting the reluctance of the arc suppression coil312. The arc suppression coil320may be adapted to form a virtual air gap314in a transformer core of the arc suppression coil312, for example at a limb and/or a yoke of the arc suppression coil312. One example for forming a virtual air gap314is given as follows. A virtual air gap314may be formed electrically, for example by at least one winding wound at the arc suppression coil312in a transformer core of the arc suppression coil312. The winding may be wound at a transformer core of the arc suppression coil312, for example partially or fully around a limb316and/or a yoke of the arc suppression coil312, e.g. through the limb316and/or the yoke. For the purpose of forming the virtual air gap314, the arc suppression coil312may comprise a separate path adapted for carrying zero sequence magnetic flux, for example in form of a loop. While the arc suppression coil312may be formed The magnitude of the virtual air gap314may be adapted to be controlled by feeding current, for example DC current, into the winding. The winding(s) may be adapted to locally saturate the magnetic core of the path, when fed with the current, creating an effect similar to an air gap in the path and thereby increasing the reluctance of the path. The winding(s) may be arranged so that there is no induction to the winding circuit from the AC (alternating current) windings of the arc suppression coil312or the arrangement150connected to the phased power lines of the network112. The virtual air gap314allows substantially linear operation of the arc suppression coil312. It also allows very fast tuning, e.g. adjusting inductance of the arc suppression coil between a high and a low value in milliseconds. With electrical control of the reluctance of the arc suppression coil312, no motors and/or moving parts are required, which may allow the size, cost and maintenance requirements of the arrangement150to be reduced. The arc suppression coil312may be formed as a conventional arc suppression coil310with adjustable reluctance and used together with a separate earthing transformer. However, as stated above, the arc suppression coil312may also be formed as one monolithic structure functioning both as an earthing transformer and an inductive compensator for the capacitive reactance of the network112. The arc suppression coil312may, for example, comprise a three-phase reactor for grounding the network112having three limbs and the separate path for zero sequence magnetic flux may be formed between the opposing ends of the three limbs of the three phase reactor, for example through a fourth limb. In an example, the arc suppression coil312comprises four or more limbs316, where the arc suppression coil312is adapted for a path for zero sequence flux to be created through one of the limbs. The arc suppression coil312comprises means for forming a virtual air gap314for adjusting the reluctance of the path. The three other limbs comprise windings and connections for the three phases of a three-phase network112. The path is formed as a return path for flux between the opposite ends of the three limbs. The design of the arc suppression coil312may correspond to that of a traditional reactor. The path with the virtual air gap314provides one example which allows capturing a part of the leakage flux of an arc suppression coil312for controlling the inductance of the arc suppression coil312. FIG.4is a schematic diagram of a system400for operating an electric power network compensated by an arc suppression coil according to an example. The system400is adapted to be electrically connected to the arrangement150for earth fault compensation. Moreover, the system400is adapted to be electrically connected to the network112, for example to the bus130. The network112may be, for example, delta-connected. The system400may be a local system, for example at an electrical substation or at a distribution transformer. The system400comprises an apparatus410, such as a controller, for operating the electric power network, in particular by operating an arc suppression coil of the arrangement150. The apparatus410may be adapted to function as a stand-alone unit but for many typical applications, the apparatus410can be adapted to function as a part of a distributed system430for controlling the network112, e.g. it may be a remote terminal unit (RTU), such as an RTU of a SCADA system. The apparatus410may be adapted to be connected to the network112, e.g. to the bus130, for determining information indicative of the status of the network112, e.g. a resonance point of the network such as a normal state and/or fault state resonance point of the network112. The apparatus410may comprise at least one processor and at least one memory comprising computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, receive an indication for an occurrence of an earth fault in the network112and tune the arc suppression coil of the arrangement150away from resonance with respect to a resonance point of the network112, while the earth fault is present in the network112, to increase fault current in the network112for tripping one or more protective relays in the network112. The at least one memory and the computer program code can be further configured to, with the at least one processor, perform any or all of the functions disclosed herein for operating the arc suppression coil and/or determining information indicative of the state of the network112such as the zero sequence voltage of the network112and/or the negative sequence current of the network112. The apparatus410is electrically connected to the arc suppression coil for operating the arc suppression coil, in particular for adjusting the inductance of the arc suppression coil. Specifically, while the apparatus410is adapted to adjust the inductance of the arc suppression coil during normal operation of the network112, the apparatus410may be adapted to adjust the inductance of the arc suppression coil also while the earth fault is present in the network112. This means that the arc suppression coil can be tuned with respect to the resonance point of the network112both in the absence and presence of an earth fault. For tuning the arc suppression coil, the apparatus410may be adapted to control one or more analog outputs (VCOMP) for controlling the inductance of the arc suppression coil, for example by feeding current, such as DC current, to the one or more windings adapted for forming a virtual air gap314for adjusting the reluctance of the arc suppression coil. Voltage- and/or current-based control may be used. The system400may comprise a converter420, e.g. a DC-DC converter or an AC-DC converter, between the arc suppression coil and the apparatus410. The converter420may have, for example, an analog input of 0-10 V from the apparatus410and/or a current output of 0-30 A to the arrangement150. The apparatus410may be grounded to an earth440, which may be the earth340of the arrangement150for earth fault compensation, for example by a direct connection. The apparatus410may be arranged to function independently for tripping the one or more relays142in the network112. For this purpose, it may use one or more measurements indicative of zero sequence voltage of the network112and/or one or more measurements indicative of negative sequence current voltage of the network112. Alternatively or additionally, other types of measurements may be used. The one or more measurements may be local measurements. The one or more measurements may be performed at the bus130, e.g. at a substation bus. The apparatus410may be adapted to function without separate configuration with respect to the network112. For example, it does not need to know the magnitude of the capacitance of the network112. It is enough to use the measurements indicative of the zero sequence voltage and/or the negative sequence current of the network to operate the arc suppression coil. The zero sequence voltage may be maximized, for example, by dithering. The system400may comprise a gateway432for remote communication with one or more external systems, e.g. with a distributed system430such as a SCADA system. The apparatus410may be adapted to be connected to the one or more external systems430through the gateway432. For example, the gateway432may conform to the standard IEC 61850 and/or IEC 60870, such as IEC 60870-5-104. FIGS.5a,billustrate operating an electric power network112according to an example. In the figures and in the text below, an example development of the zero sequence voltage V0of the network112is illustrated as a function of time. It should be understood that additionally or alternatively to any determination indicative of a voltage, such as the zero sequence voltage of the network, another determination, such as a determination indicative of the fault current in the network e.g. a determination indicative of the negative sequence current of the network, may be used. A threshold for voltage may thereby be replaced by a threshold for current. During normal operation of the network112the zero sequence voltage remains below a first threshold voltage VH. The occurrence of an earth fault can be determined based on an increase of the zero sequence voltage above the first threshold voltage VH. In response, the arc suppression coil may be tuned in one or more attempts to try to remove the earth fault. This corresponds to initiating a tracking mode for attempting to remove the earth fault. If the attempt is successful, a case illustrated inFIG.5a, the zero sequence voltage decreases. The disappearance of the earth fault can be determined based on a decrease of the zero sequence voltage below a second threshold voltage VL. Once it has been determined that the earth fault has disappeared, the arc suppression coil can be returned to off-resonance for normal operation of the network112. If the attempt is not successful or if no attempts are made, a case illustrated inFIG.5b, the zero sequence voltage remains at an elevated level. In this case, the arc suppression coil may be tuned away from resonance to trip one or more relays for protecting the network112and its surroundings. This corresponds to initiating a protection mode for removing current from the faulty feeder. The finite time required for a relay to react has been illustrated in the figure but it should be noted that this is not necessarily in scale and the actual reaction time may be small. Once the current has been removed, the zero sequence voltage decreases. The removal of the fault current can be determined, for example, based on a decrease of the zero sequence voltage below the second threshold voltage VL. Once it has been determined that the fault current has disappeared, fault location, isolation and removal operations may be performed for the network112. The tripping may be performed by tuning the arc suppression coil, for example by tuning the one or more analog outputs of the apparatus410. This may be performed by tuning the arc suppression coil away from resonance until the zero sequence voltage falls below a tuning threshold, which may be a configurable parameter. The tuning threshold may be, for example, determined as a proportion of a maximum zero sequence voltage recorded, whether it is under normal operation or in the presence of the earth fault. Tuning for keeping the zero sequence voltage below the tuning threshold may be maintained until the zero sequence voltage drops below the second threshold voltage VL. The tuning may be maintained as a constant tuning or as a changing tuning moving increasingly away from resonance, e.g. by continuous or sequential increases. It is noted that a first threshold value, such as the first threshold voltage VHor a first threshold current, may be used for determining the occurrence of an earth fault. Also, a second threshold value, such as a second threshold voltage VLor a second threshold current, may be used for determining the disappearance of an earth fault. The first threshold value and/or the second threshold value may be compared, for example by the apparatus410, to the zero sequence voltage of the network or a value indicative thereof and/or to the negative sequence current of the network or a value indicative thereof. The apparatus410may be adapted to bring about measurement of the zero sequence voltage or a value indicative thereof and/or of the negative sequence current of the network or a value indicative thereof, for example from the bus130. The first threshold value and the second threshold value may be the same but they can also be different, for example so that the first threshold value corresponds to a larger value than the second threshold value. This can be used to reduce the occurrence of false positives and/or negatives for determination of the presence of the earth fault. FIGS.6aand6billustrate examples of relay characteristics. These particular examples illustrate angular relay characteristics, where a relay can be configured to operate, e.g. trip, based on a phase difference. Various different relay characteristics, as such, are known to a person skilled in the art for configuring protective relays such as the one or more relays142. The example characteristics are illustrated in a complex plane so that the relation between the zero sequence voltage V0and the sum current I0can be observed. The sum current can be determined as a sum of the phase currents in the network112, e.g. in a feeder. In particular, the phase difference608between the zero sequence voltage and the sum current can be used as basis for tripping the relay, for example as illustrated in the figures. However, various other relay characteristics exist as well, for example where tripping is based on effective or parasitic values of the sum current. In the examples, the relay is in normal operation, i.e. not-tripped, when the phase difference608corresponds to a normal operation region602in the relay characteristics. In addition, there is typically a threshold606for the magnitude of the sum current, below which the relay remains in normal operation. On the other hand, if the phase difference608and/or the magnitude of the sum current correspond to an activation region in the relay characteristics, the relay is configured to trip. The activation region may be defined by one or boundaries604. It may be a complement of the normal operation region602. Typically, relays in compensated networks are configured with the relay characteristics of a compensated network, such as the compensated network angular relay characteristics600illustrated inFIG.6a. In this example, the base angle is zero and the range of variation is, for example, within −88 and +88 degrees. However, it has been noted that the present disclosure may be efficiently utilized when the one or more relays142are configured with relay characteristics of an isolated network, for example as the isolated network angular relay characteristics610illustrated inFIG.6b. For angular relay characteristics, the base angle612may then be 90 degrees. The range of variation may remain substantially within −88 and +88 degrees. The boundaries604of the activation region may thereby be defined substantially at 2 degrees and at 178 degrees, for example at 2 plus/minus 0-1 degrees and at 178 plus/minus 0-1 degrees. The apparatus may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The application logic, software or instruction set may be maintained on any one of various conventional computer-readable media. A “computer-readable medium” may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable medium may comprise a computer-readable storage medium that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. The exemplary embodiments can store information relating to various processes described herein. This information can be stored in one or more memories, such as a hard disk, optical disk, magneto-optical disk, RAM, and the like. One or more databases can store the information used to implement the exemplary embodiments of the present inventions. The databases can be organized using data structures (e.g., records, tables, arrays, fields, graphs, trees, lists, and the like) included in one or more memories or storage devices listed herein. The databases may be located on one or more devices comprising local and/or remote devices such as servers. The processes described with respect to the exemplary embodiments can include appropriate data structures for storing data collected and/or generated by the processes of the devices and subsystems of the exemplary embodiments in one or more databases. All or a portion of the exemplary embodiments can be implemented using one or more general purpose processors, microprocessors, digital signal processors, micro-controllers, and the like, programmed according to the teachings of the exemplary embodiments, as will be appreciated by those skilled in the computer and/or software art(s). Appropriate software can be readily prepared by programmers of ordinary skill based on the teachings of the exemplary embodiments, as will be appreciated by those skilled in the software art. In addition, the exemplary embodiments can be implemented by the preparation of application-specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be appreciated by those skilled in the electrical art(s). Thus, the exemplary embodiments are not limited to any specific combination of hardware and/or software. The different functions discussed herein may be performed in a different order and/or concurrently with each other. Any range or device value given herein may be extended or altered without losing the effect sought, unless indicated otherwise. Also any embodiment may be combined with another embodiment unless explicitly disallowed. Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims. It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to ‘an’ item may refer to one or more of those items. The term ‘comprising’ is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements. It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification. | 38,151 |
11862962 | DETAILED DESCRIPTION The invention can be implemented in numerous ways, including as a process; an apparatus; a system; a composition of matter; a computer program product embodied on a computer readable storage medium; and/or a processor, such as a processor configured to execute instructions stored on and/or provided by a memory coupled to the processor. In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the invention. Unless stated otherwise, a component such as a processor or a memory described as being configured to perform a task may be implemented as a general component that is temporarily configured to perform the task at a given time or a specific component that is manufactured to perform the task. As used herein, the term ‘processor’ refers to one or more devices, circuits, and/or processing cores configured to process data, such as computer program instructions. A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured. FIG.1illustrates an embodiment of a power system. In this example, the main panel (102) distributes electricity from a main feed (e.g., from the meter104) to all of the different circuits of a location such as a home. In this example, grid power comes from the meter. The main panel may include a main circuit breaker106(also referred to herein as a “main breaker”) that disconnects the utility feed from the loads in the house in the event of a thermal fault, high current due to short circuit, etc. In this example, the power system includes an energy storage system (ESS)108. As one example, the energy storage system is a battery storage that is part of an on-site solar-battery power system. In this example, the ESS connects through one of the branch circuits of the main panel in the house. For example, suppose there are 24 circuits in the house, where one goes to a dryer, one goes to a hot water heater, one goes to the living room, one goes to an upstairs bedroom, etc. In this example, one of the circuits goes to the ESS. As one example, the ESS is a part of an onsite power system, such as an onsite solar battery system, that includes a photovoltaic (PV) array that generates solar power, as well as an onsite battery storage system that is coupled to the PV array. In some embodiments, the onsite power system includes an inverter. The inverter converts DC power from the PV array and/or batteries to AC power that can be used to power the loads of the home, such as in conjunction with the grid, or when the home is isolated from the grid (e.g., due to a utility grid blackout). In this example, the ESS, loads, meter, etc. are electrically connected via the bus of the main panel. Thus, if the grid is disconnected by opening the main breaker, then if the ESS is able to provide voltage/power through its connection to the bus, then the ESS can provide power to the entire home, instead of the grid (i.e., forming a microgrid in which the home site is isolated from the utility grid). In existing power systems, when the utility grid goes down, the voltage on the grid drops to zero, causing the house to black out, as the home's voltage is also brought to zero. In order to bring the home back, the home should be disconnected from the failed grid so that the ESS can now supply power to the home. In some cases, this is a certification requirement for backup power sources to be isolated from the grid when supplying backup power. It would be beneficial if, in the event of a grid failure, or in the event of a predicted or anticipated grid failure, or it is detected that the health of the grid is declining, that the home could be quickly disconnected from the grid to allow for operating in a backup power mode (e.g., where the ESS is the power source). In some embodiments, if this disconnect occurs sufficiently quickly (e.g., several 60 Hz cycles), then the operation of digital electronics within the home will not be interrupted. This would also be beneficial in the absence of grid failures, for example when there may be financial benefits to isolating from the grid. One example of implementing a grid disconnect is to include a controllable relay in series with the main breaker. For example, a relay is inserted between the meter and the panel. The entire home may then be disconnected from the grid by opening the relay, allowing the whole home to be powered from the connected ESS. In some cases, the meter is in the main panel, and the two are unable to be separated. In some embodiments, to address this, another panel is installed, where existing circuit breakers are moved from their original panel to the new panel. The new panel is then fed from the old panel, where a relay such as that described above is installed between the two panels. As one example, the new panel (also referred to herein as a “grid interface panel”) includes an integrated relay. In this case, while the loads are still moved from an existing panel to a new one at the time of installation, a separate relay need not be installed between the old panel and in the new panel (as it is integrated in the new panel). There are various challenges with the installation of the new panel boxes described above. One example is the long installation time required to install such boxes. Another issue is load relocation. For example, one installation scenario involves relocating circuits that are in a home's existing main panel, for example by installing a bridge box as a sub-panel, and then rewiring all of the circuits from the existing main panel to the sub-panel. Even installation scenarios that do not involve load relocation can be time consuming. For example, at a minimum, multiple large gauge conductors would still need to be routed into and out of the newly installed box, which is time-consuming and expensive. An alternative embodiment for providing a controllable grid interface mechanism is to replace an existing main breaker with what is referred to herein as an intelligent, or smart, main breaker, where the smart main breaker described herein provides not only the safety functionality of main breakers, but also provides controllable actuation of the main breaker, so that it can effectively operate as a controllable grid interconnect switch as well (e.g., to isolate from, or reconnect to the grid as desired). Further embodiments of a smart main breaker are described below. Described herein are embodiments of a smart main breaker that, in addition to performing the function of a breaker for safety, also provides the function of a microgrid interconnect device. Further, the integrated smart main breaker is packaged in a form factor that is designed to be plugged into the same location as a home's existing main breaker. As will be described herein, the integrated device provides multiple functions in a single package. For example, the integrated device includes breaker functionality to serve the function of overcurrent and thermal safety protection—that is, it provides a safety mechanism for interrupting current in an overcurrent situation. The integrated device is also controllable, allowing actuation of the breaker to disconnect the home site from the grid in scenarios such as brownouts or blackouts. As will also be described in further detail below, the integrated smart main breaker device is programmed so that it can autonomously make decisions on when to close or open the main breaker to connect or disconnect the home from the grid. The intelligent main breaker also includes communications to allow coordination with a power source device (e.g., inverter of a home solar battery system). As will be described in further detail below, the form factor of the controllable main breaker device is selected so that it can be packaged into existing panels, avoiding the need (and associated time and expense) to install a new panel and perform relocating of loads. Embodiments of the smart main breaker device described herein address the aforementioned issues with existing implementations of microgrid interconnect devices. For example, using the smart grid interconnect breaker described herein eliminates the need for installing a new box. Instead, an existing box/panel is utilized. This provides various benefits. For example, installation time is reduced, where this reduction in overhead would allow an electrician to perform more installations in a day. For example, in some embodiments, an existing main breaker is replaced with the controllable main breaker described herein that not only serves the safety purpose of a breaker, but is also controllable so that the circuit can be opened when desired (and not just when there is a fault). The controllable grid interface breaker mechanisms described herein provide various benefits, including simplified installation, as well as simplified manufacturing and certification. Further, combining the microgrid interconnect functionality within a main breaker avoids placing the grid interconnect device in other components such as meters, which would involve certification with utilities. As another example benefit, the use of such an intelligent main breaker does not require coordination with a utility. The following are embodiments of an intelligent main breaker that also provides integrated microgrid interconnect functionality. As will be described in further detail below, the intelligent main breaker provides safety functionality (via the main breaker and overcurrent and thermal triggers), as well as microgrid interconnect functionality (e.g., by intelligent and controllable triggering of the opening and closing of the main breaker). In the following examples, existing main breakers are replaced with a controllable main breaker, or are augmented or otherwise adapted to become controllable to also function as a controllable grid interface relay. In some embodiments, existing breaker functionality is leveraged to connect or disconnect from the meter. The mechanisms described herein provide existing breaker safety functionality, while adding (remote) controllability of the breaker mechanism to allow smart connect/disconnect from the grid. For example, the controllable breakers described herein may be opened very quickly, as well as be closed, while still serving the purpose of a breaker to provide critical safety functions. In some embodiments, the controllable breakers described herein, in addition to providing safety functionality, are also actuatable to function as a controllable relay. Thus, in various embodiments, the controllable grid interface breakers described herein may be used as a home disconnect relay (e.g., for backup purposes). Smart Main Breaker Architecture FIG.2illustrates an embodiment of an architecture of a smart main breaker. As shown in this example, the intelligent main breaker200includes a main breaker202. The main breaker is configured to perform the safety feature of providing thermal or overcurrent protection. The breaker provides a way to disconnect the home from the grid in case of safety issues. For example, when the main breaker is opened, the load side connection204(e.g., to home loads) and grid side connection206(e.g., to the meter/grid) are electrically disconnected from each other. When it is safe again, a user can reset the main breaker, and reconnect the home to the grid. In effect, main breakers provide a way where the home can be disconnected and reconnected to the grid. In some embodiments, the smart main breaker leverages the main breaker mechanism to perform the function of a controllable interconnect switch by providing a controllable actuator that can open and close the breaker as desired (rather than only due to unsafe conditions), where the controllable actuator is controlled via intelligence local to the smart main breaker, and can disconnect or reconnect the grid side from the load side (e.g., home). That is, the resettable main breaker is leveraged to also provide intelligent grid interconnect functionality, where a controllable actuator is included in the smart main breaker so that the main breaker can also be used as a grid interconnect switch. The following are further embodiments of an architecture of a smart main breaker. Main Breaker/Safety Functionality Triggers In some embodiments, to provide existing safety functionality, the smart main breaker architecture includes components such as contacts that may be opened and closed (e.g., to break or close a circuit). In some embodiments, the smart main breaker includes a spring-loaded mechanism that snaps the contacts open when triggered. The opening of the contacts may be triggered in a variety of ways. For example, for thermal safety purposes, the smart main breaker includes a bimetal strip208that warps when heated, causing the trigger mechanism to be actuated when the current is too high for too long (e.g., thermal tripping). In this example, the smart main breaker may also include, for overcurrent safety protection, a coil/solenoid mechanism210, where the current flowing through the coil provides a linear magnetic force on an actuator. When there is a high current through the breaker, the magnetic force increases and triggers the actuator, causing the contacts to quickly open. The smart main breaker may also include arc extinguishing mechanisms (e.g., arc shoots or channels such as metal fins). Controllable Actuators for Opening and Closing the Main Breaker In some embodiments, to provide remote control functionality, the smart main breaker includes controllable mechanisms/actuators212for opening and closing the main breaker. For example, for opening the main breaker, the smart main breaker includes an additional actuator/trigger that is electronically controllable for tripping the breaker on demand. As one example, the additional actuator is a coil/solenoid mechanism that is electronically controllable (rather than, for example, being driven by the primary breaker current). In some embodiments, the solenoid takes power from the voltage on the lines, and when disconnection from the grid is desired, voltage is placed on the coil, which, for example, pushes another coil that pushes the trigger, causing the breaker to open whenever desired. As shown in this example, in addition to two trigger mechanisms for safety, such as the warping bimetal strip for thermal triggering, and a solenoid/coil for high current triggering, the controllable breaker described herein includes an additional trigger mechanism for controlling opening of the main grid interface breaker (to effectively disconnect from the grid). In some embodiments, the additional controllable trigger actuates in response to a command from a microcontroller of the smart main breaker, further details of which are described below. Reset Motor In some embodiments, in order to close the main breaker (e.g., to reconnect the load side and the grid side together), the smart main breaker includes a controllable mechanism such as a controllable motor for closing or resetting the breaker when desired. Electronics for controlling the actuator and the reset mechanism may also be included in the main breaker. For example, a closing motor may be included that, on command, reloads springs for closing the contacts of the controllable breaker. This provides, for example, a controllable spring-loaded triggerable contact that may be opened and closed when desired. In some embodiments, the controllable reset mechanism is controlled by commands from a microcontroller of the smart main breaker, further details of which are described below. Interlocking Mechanism In some embodiments the controllable breaker is configured with logic that detects when the breaker is triggered due to detection of a fault (e.g., a thermal fault or short circuit). In some embodiments, if it is detected that the breaker triggered due to a fault, the breaker is prohibited from being remotely closed via remote control. For example, detection of the breaker being triggered due to the bimetal strip or the high current solenoid/coil prevents the motor mechanism from being allowed to run or operate. This satisfies any requirement for a manual reset in the event of the breaker opening due to a short circuit or thermal fault. For example, the remote control of the motor is disabled until a user manually resets the tripped breaker. The following are examples of interlocking mechanisms. In some embodiments, an interlock mechanism is used to interlock the motor in the event that a fault occurs (e.g., thermal fault or short circuit), as described above. In some embodiments, the interlock is a mechanical interlock. In other embodiments, the interlock is an electronic interlock. The interlock may also be an electromechanical interlock. As one example of a mechanical interlock, the triggers that actuate due to faults (e.g., bimetal strip or high current solenoid/coil described above) are mechanically set up such that if any of those triggers, this also causes the movement of a contact that opens the circuit of the motor (e.g., at the terminals), preventing the motor from operating or running. The interlock mechanism may then be reset when the user resets the breaker mechanism. As one example of electronic interlocking, in some embodiments, sensors are placed on the triggers that actuate due to faults (e.g., bimetal strip or high current solenoid/coil described above). When any of those are actuated, this also causes the motor circuit to be opened to prevent the motor from being able to run. In some embodiments, the breaker does not have a switch. While existing breakers may have a physical input such as a button or lever for the user to actuate, the controllable replacement breaker need not have the same shape or type of existing lever. For example, the controllable breaker need not have a lever. As one example, the controllable breaker may have an indicator such as a status light (e.g., red and green status indicator lights), as well as a reset button (where the reset input need not be a lever even if the existing breaker being replaced included a lever). In some embodiments, when the user presses the reset button, this causes the motor mechanism described above to be automatically used to drive the reset mechanism, resetting the breaker. In other embodiments, the reset switch physically causes resetting. As shown in the above example, even though the existing breaker being replaced may have had a lever, the intelligent main breaker described herein need not have the identical or same type of lever. If the smart main breaker is being implemented in a modular manner (as will be described in further detail below), where there is a standardized core component of a modular controllable breaker, then this standardized core component need not have the identical or same lever. This allows further standardization of the core component so that there need not be core components for different types of levers, switches, reset buttons, lights, indicators, etc. In some embodiments, the breaker components are designed for robustness to allow a high cycle life, as the breaker may be opened many times and have higher cycle time requirements than typical breakers. Microprocessor Intelligence for Controlling the Controllable Actuator As described above, the smart main breaker includes a controllable actuator for opening or closing the main breaker to provide grid interconnect functionality. The inclusion of an additional controllable actuator (e.g., controllable actuators for opening and closing the main breaker) allows the safety function of the main breaker to be maintained, while also providing the ability to control connection to/disconnection from the grid. In some embodiments, the smart main breaker includes a microprocessor214. In some embodiments, the microcontroller is a programmable microcontroller on which intelligence and algorithms can be deployed on (e.g., by programming firmware of the programmable microcontroller). Further details regarding such functionality are described below. In some embodiments, the microprocessor or microcontroller provides onboard intelligence. The onboard intelligence is used to, for example, allow the device to autonomously determine when to turn on or off the connection to the grid (e.g., by sending instructions or commands to the controllable actuators212to open or close the main breaker), as well as other functionality. In some embodiments, by making intelligent decisions on disconnecting from, or reconnecting to the grid, this ensures seamless power transitions for the homeowner, minimal numbers of transitions, as well as adherence to any present or future certification requirements for smart inverters, grid connected devices, backup power sources, and/or microgrid interconnect devices. In some embodiments, the microprocessor includes I/O that is connected, for example, to sensors216, communications218, etc. The microprocessor also includes I/O to communicate internally with the controllable actuators212for opening and closing the main breaker202. This provides an interface by which the microprocessor can command the controllable actuator to open or close the main breaker to effect grid disconnect or reconnect. The microprocessor also communicates with the communications module218so that it can receive information from, and send information to, external devices. In various embodiments, the smart main breaker is powered by the onsite power system and/or the grid. In some embodiments, the smart main breaker includes a battery. In some embodiments, the battery is included to operate the switch when both grid power and backup power are unavailable. As shown in this example, the smart main breaker device may be designed with multiple sources of input power, such as grid side, load side, hardwired, and battery, etc. in order to remain operational in the maximum number of outage conditions. Sensors In this example, the smart main breaker includes sensors216for sensing electrical characteristics such as voltage, current, phase, amplitude, frequency, etc. In some embodiments, the sensors are used to measure both grid side and load side (e.g., home side) electrical characteristics. Communications In this example, the device includes communications module218for communicating with devices external to the device. Examples of communications interfaces include CAN (controller area network) communications, powerline communications (PLC), WiFi, ethernet, or any other wired and/or wireless communications as appropriate. As one example, a communications protocol such as RS485 is used. As shown above, in some embodiments, the smart main breaker includes electronics for controlling the triggering (e.g., opening) of the contacts in the breaker, as well as closing/resetting of the breaker. In some embodiments, the controllable actuator is implemented using a controllable solenoid that is connected via wires to the microprocessor. In some embodiments, the microcontroller then puts voltage on the wires to trigger the actuating mechanisms described above. For example, the controllable breaker includes the additional trigger mechanism, motor (e.g., for resetting the breaker after it is opened), an interlocking mechanism as described above, a mechanism for resetting the interlock, as well as other associated electronics. As described above, in some embodiments, the smart main breaker also includes additional processing logic, communications (e.g., powerline communications, WiFi componentry, etc.), etc. In some embodiments, the mechanisms for controlling the opening/closing of the breaker as a relay are designed to not interfere with the safety functioning of the breaker (e.g., so that the breaker can still open in the event of thermal faults or short circuits). As also described above, in some embodiments, the smart main breaker includes a motor reset mechanism. In some embodiments, the smart main breaker includes a third or additional controllable trigger mechanism (e.g., solenoid), as described above. As one example, the controllable trigger mechanism may act, for example, as a type of push button that behaves as a manual trip. As one example, the replacement breaker includes a button that may be toggled or actuated, such as a push button. A controllable solenoid and motor accessory may then be placed over the button. The controllable motor accessory may then actuate the button on the smart main breaker. Such an implementation may be used in space constrained scenarios. For example, suppose that a manual shutoff button was included in the replacement breaker, but there is not sufficient space to include a solenoid that could actuate the button. In some embodiments, the solenoid is placed externally, and is configured to push that button. Similarly with the motor, if there is insufficient space within the breaker that goes in the slot, a user input or control that a user may toggle or actuate may be included in the breaker that fits within the slot, where the breaker component is augmented with an external motor accessory that actuates the control (e.g., physical button or lever). Smart Main Breaker Intelligence As described above, the intelligent main breaker includes a microprocessor and a controllable actuator for opening and closing the main breaker (e.g., solenoid for opening the main breaker, and a motor for resetting the main breaker, as described above). In some embodiments, the microprocessor is programmable with a layer of firmware. In some embodiments, the microprocessor is configured with logic to determine when to connect to the grid, and when to disconnect from the grid (e.g., isolate the home from the grid). Based on this intelligence, the microprocessor then issues commands to the controllable actuator to open/close the main breaker to cause the disconnection from/reconnection to the grid. For example, the integrated smart main breaker device is programmed with functionality to open due to a brownout or when the grid is down so that the solar battery system can isolate from the grid and allow the microgrid at the home to be stood up. The decision making on how to control opening and closing of the grid interconnect switch is based on a variety of inputs including, without limitation:Sensor measurements (e.g., from sensors216): such as measurements that indicate that the grid is going downMessages: This includes messages communicated from partner devices. For example, an energy management system for the home battery system may send a message indicating that it would like to form a microgrid, and make a request to the integrated breaker and grid interconnect device to open the grid interconnect switch. The following are examples of intelligent functionality supported by the intelligent main breaker described herein. The use of backup devices such as generators often involve transfer switches, because the generators are not to be operated in parallel with the grid, and so the transfer switch determines one power source or the other, but does not allow a connection to both simultaneously. This is in contrast to solar battery systems such as that described herein, which operate both on-grid and off-grid. For example, the intelligent main breaker is configured to enable a power source such as the inverter to be connected in both scenarios. In some embodiments, the intelligent main breaker and onsite power source (e.g., inverter) are configured to communicate with each other. This allows, for example, status information to be passed between the inverter and the integrated breaker/interconnect. The passing of status information allows the integrated breaker interconnect device to make appropriate decisions and not enter an improper state. As one example, suppose that the inverter (example of an onsite power source) is not operational (e.g., because somebody has manually opened an inverter relay). Now suppose that a brownout has occurred. In this case, because the inverter is down, the integrated device should not open, and should stay connected to the grid. This is so that the home will have power as soon as the grid returns. As the inverter is not operational, it would not be beneficial to disconnect from the grid and island or isolate the home from the grid (as there would be no power source to form a microgrid). In some embodiments, the intelligent main breaker uses status information of the inverter as an input to determine whether to open its switch. As another example, suppose that the inverter was operational, and that during a brownout, the smart main breaker device had opened, isolating the home from the grid, where the inverter was the sole power source for the home. Now suppose that the grid is back up (which the intelligent main breaker device determines based on electrical measurements of the grid-side using its sensors). The intelligent main breaker should reconnect the home to the grid in this case. This would also cause the inverter (which may be delivering power) to also be connected to the grid. However, the reconnection should not occur until the inverter is synchronized with the grid (so that the inverter is in grid following mode, where the electrical characteristics of the inverter's power output follow the grid). For example, the grid and inverter power source should align in phase, amplitude, and frequency before reconnection to the grid is performed. In some embodiments, prior to closing of the main breaker of the smart main breaker, the microprocessor is configured to determine characteristics of the grid for synchronization with the onsite power source. This includes measuring phase, amplitude, and frequency of the grid. The smart main breaker then uses its communications module to communicate the measured grid electrical characteristics to the inverter. The inverter then uses the grid characteristic information to adjust its output to match the grid side characteristics. In this example, the smart main breaker measures the power provided by the inverter on one side, and the characteristics of the power from the grid side and the load side. When the smart main breaker determines that both sides are synchronized, the microprocessor instructs the controllable motor to close the main breaker so that the home and the grid are reconnected. As shown in the examples described herein, the onsite power source can operate as grid following or grid forming. When the home is on grid, the power source is to operate in a grid following mode. When the home is off-grid, the power source is to operate in a grid forming mode (e.g., where the home is isolated from the grid, and the home is in an effective island or microgrid state in which the onsite power source is delivering power to the loads at the site). As shown in the above examples, in order to determine when it is appropriate for the onsite power source to enter one mode or the other, communication and coordination with the intelligent main breaker is performed so that status information can be passed between the interconnect device and the inverter onsite power source. The following are further embodiments and examples of such coordination. When the main breaker is open and the onsite power system is disconnected from the grid, then the onsite power system should be in a state where it is capable of forming a microgrid and providing power to the loads of the home. As one example, the inverter is programmed to enter grid-forming mode on the condition that the home is disconnected from the grid. Thus, before switching to grid-forming mode, the inverter checks for the status of the interconnect switch to determine if it is opened or closed. If the smart main breaker/grid interconnect switch is closed, then the inverter is not permitted to enter grid-forming mode. As another example, before the inverter switches state to grid-following mode, the inverter checks with the smart main breaker to determine whether the grid is back up. If so, then the inverter switches to grid-following mode, and also coordinates resynchronization with the grid as described above using, for example, information collected and communicated by the intelligent main breaker device. As shown in this example, in some embodiments, when the main breaker is closed and the onsite power system is connected to the grid, then the onsite power system is to operate in a grid following mode, and the onsite power waveform and the grid power waveform should be synchronized. As shown in the above examples, the smart main breaker for solar and battery systems described herein facilitates communication between the grid interconnect device and the inverter. As described above, in some embodiments, the intelligent and controllable main breaker device includes a microprocessor so that it has local autonomy to determine what actions to take. It also includes communications to allow communication with external intelligent devices (e.g., on site power source), so that information from external devices may also be used as input for the microprocessor. In this way, appropriate actions will only be taken when there are correct signals from both devices, such that they are coordinated. However, if there are some issues with the communication, then the smart main breaker uses its included intelligence so that it can enact secondary or fallback or primary directive plans to perform safe actions in the event of it being unable to communicate with the inverter. As shown in the examples above, in some embodiments, the inverter of the ESS is configured to switch between two operating modes: grid-following mode (when the home is on-grid), and grid-forming mode (when the home is off-grid). The smart main breaker is configured to determine whether to open or close the main breaker (effectively disconnecting or connecting the home from/to the grid). In some embodiments, the state of the inverter (e.g., which operating mode it is in), and the state of the smart main breaker (e.g., whether the main breaker is opened or closed) are based on coordination between the inverter and the smart main breaker. That is, the state of the inverter is based on the state of the smart main breaker, and vice versa. The behavior of the inverter and the smart main breaker is also dependent on a variety of factors that are context specific. The following are further embodiments of intelligently determining whether to open or close the main breaker of the smart main breaker described herein. In some embodiments, the logic for such a determination is implemented in firmware and executed by the microprocessor of the intelligent main breaker. Embodiments of Disconnecting a Site from the Grid In some embodiments, the smart main breaker includes logic for determining the conditions under which disconnect from the grid is permitted (and also the conditions under which the smart main breaker is prohibited from disconnecting from the grid. As one example, suppose that the home is currently connected to the grid. However, the smart main breaker determines, based on its sensors, that the voltage on the grid is beginning to sag. This is an indication to the smart main breaker that the grid may be going down. In this case, the smart main breaker prepares to disconnect from the grid. Prior to opening the main breaker, the smart main breaker is configured to determine a state of the onsite inverter power source. In this example, the smart main breaker first checks to determine whether the inverter is capable of handling the home loads. For example, if the inverter is not capable of handling the home loads, then the smart main breaker does not disconnect the home from the grid, as this may cause the inverter to fault or trigger its own relay if it is unable to support the loads in the home. As another example, suppose that the inverter is not available at all (and is non-operational). In this example, it would be a poor user experience for the customer if the home were disconnected from the grid, as they will then go from a brownout situation to a blackout situation (because the inverter cannot be a power source at all). As such, in some embodiments, the microprocessor of the smart main breaker is programmed such that even if it is determined that there is an indication that the grid is going down (and would be unable to deliver electricity), it does not disconnect from the grid if the inverter power source is determined to be unavailable or incapable of powering the home loads. As shown in the above examples, prior to taking the action of opening the main breaker and disconnecting the home from the grid, the smart main breaker determines whether the onsite power system is in a condition or state to form a microgrid (e.g., is operational, is able to provide sufficient power for the loads of the home, etc.). If so, then the smart main breaker opens the interconnect grid switch, disconnecting the site from the grid. The above are examples of coordination between the smart main breaker and a solar battery system that allows the smart main breaker to determine whether or not to disconnect from the grid. Embodiments of Reconnecting a Site to the Grid Coordination between the smart main breaker and the solar battery system is also performed by the smart main breaker to determine whether or not to close the main breaker and reconnect to the grid. For example, if the grid comes back after a blackout, it is often the case that the grid will reach a nominal voltage, and will then sag again, before coming back. If the smart main breaker were to reconnect once the nominal voltage was reached, and then disconnect once the sagging was detected, and then reconnect once again when the nominal voltage was again reached, it would result in a less than ideal user experience, as the smart main breaker would be quickly toggling back and forth between reconnecting and disconnecting and then reconnecting again to the grid due to the fluctuation in voltage triggering opening/closing of the main breaker. In some embodiments, debounce or hysteresis is accounted for. As another example, suppose that the grid voltage is just at the threshold of the cutoff of when the smart main breaker would disconnect from the grid. That is, the voltage is at a level where it may be appropriate to disconnect from the grid. However, if the voltage is hovering around that level, it would not be ideal for the smart main breaker to connect and then disconnect and then reconnect. Instead, the reconnection logic is configured to be hysteretic. In some embodiments, hysteresis (where the thresholds or conditions for opening/closing the main breaker are different) is implemented by having different sets of detected grid conditions for connecting to and disconnecting from the grid. For example, there are different thresholds or criteria for opening and closing the grid interconnect switch. In some embodiments, the thresholds are coordinated with the inverter, so that the smart main breaker is aware of the inverter state. As one example, if the PV array is producing a large amount of power, and the batteries are full, then the dead band (between the threshold for opening/closing the main breaker, where the state of the main breaker (opened or closed) is not changed while in the dead band) can be broad or large. As the state of the microgrid is strong and can support the home loads stably for a duration of time, there is less urgency to reconnect to the grid, and the threshold level of grid stability before reconnection can be set higher given this inverter state (e.g., wait for the grid to be more stable before reconnection). On the other hand, if the onsite power system will only be able to further support the home for a short amount of time, then the dead band is shrunk, and reconnection to the grid may be performed even pre-emptively so that the home does not enter a state in which it is both disconnected form the grid, and the onsite power system is not operational. For example, if the onsite system is still up, but is close to becoming non-operational, then the system is pre-emptively reconnected to the grid (so that the smart main breaker does not enter into a situation where it does not have enough power to close the main breaker, which could result in the home being unable to be connected to the grid after the grid has come back). As shown in the above examples, in some embodiments, to account for such fluctuation in voltage, the smart main breaker is configured with intelligence to determine the set of conditions by which the home should continue to be islanded until the smart main breaker is confident that the grid is actually back. The following are additional conditions or criteria for determining whether to reconnect to the grid:The amount of reserve battery capacityWhether the sun is shining (and solar power is being generated by the solar panels)The power capacity of the inverter In some embodiments, loads are supported for as long as they can, and the smart main breaker waits until the grid voltage is back closer to nominal in order to reconnect. In some embodiments, resynchronization is performed as part of the reconnection process. For example, suppose that the grid is determined to be stable and that the onsite power system is also determined to be stable. In some embodiments, the smart main breaker uses its sensors to measure the electrical characteristics of the grid. The smart main breaker uses the grid electrical measurements to determine that the grid is in a stable condition. With respect to onsite power stability, in some embodiments, the smart main breaker uses its sensors for measuring the onsite power side, and the microprocessor (which is connected to the sensors via input/output (I/O)) uses the onsite power measurements to determine whether the onsite power system is stable. As another example, the smart main breaker receives status information from the ESS indicating its stability. For example, the smart main breaker queries the onsite power system for its stability status. As another example, the ESS periodically reports or provides such information to the smart main breaker. In order for the onsite power system and the grid to be reconnected, they are required to be synchronized, where the frequency, phase, and amplitude of their voltage must be within a certain tolerance of each other (that may be defined by a standard). At the point of reconnection, they may not be, and it would be unsafe to reconnect the onsite power system and the grid before resynchronization, as it would force onsite power production to stop. In some embodiments, as part of the reconnection process, before the main breaker of the smart main breaker is closed, the smart main breaker is programmed to transmit a signal or message to the inverter or ESS to start changing its power output to match the electrical characteristics of the grid. As one example, the smart main breaker uses its sensors to measure the electrical characteristics of the grid, and provides that sensor data to the ESS. The ESS then uses that information to adjust its output waveform and bring it closer to the grid waveform until they are in sync. Once the grid and ESS waveforms are determined to be in sync, then the action of closing the main breaker to reconnect the grid to the onsite power system is performed. In the above examples, the smart main breaker determines to reconnect to the grid based on detection of the grid returning to a stable condition. The smart main breaker may also be programmed to reconnect the home site to the grid under other conditions as well. As one example, suppose that there has been a blackout, and the home has been disconnected from the grid for a period of time. Suppose also that it has been cloudy, and that there has been minimal solar power produced, where the batteries have been drained. In this situation, there is no power for the inverter to deliver. In this case, based on the onsite power system being unavailable to provide power (but while there is still sufficient power for the smart main breaker to operate), the smart main breaker is configured to pre-emptively reconnect the home to the grid rather than wait for the inverter to come back. In this way, if the grid comes back online in the middle of the night (when there is no sun), the house will be powered by the grid. This is an example of a dark start condition, and in this example, the determination of the condition on which to reconnect to the grid is based on coordination between the inverter and the smart main breaker. In some embodiments, while the smart main breaker is in a disconnected state from the grid, the smart main breaker is configured to monitor the health or status of the ESS, such as its state of charge (SOC), the amount of power being produced by the panels, etc. That is, the state of the microgrid is determined. If the microgrid is determined to be unable to support or power the home loads, then the smart main breaker reconnects the home to the grid. In some embodiments, the onsite power system also includes various intelligence. As one example, the onsite power system is configured with the ability to cause load shedding to reduce the number of loads it needs to support. This can increase the amount of time in which the home can be supported by the onsite power system, and make the onsite power system more stable. As another example, in some embodiments, prior to shutting down power generation, the onsite power system is configured to transmit a signal to the smart main breaker indicating that it will be going offline. After a timeout period, the smart main breaker will perform reconnection to the grid. As described above, the smart main breaker may be powered by either the grid (e.g., via the busbar), the inverter (e.g., via the busbar connection, or a hardwired power and communication cable), and/or a battery (e.g., either manufactured directly into the smart main breaker or via a separately packaged battery connected via a dedicated power connection). If the grid is down, and the onsite power system is up, then the smart main breaker is powered by the onsite power system (e.g., by the inverter). In some embodiments, prior to the inverter going offline, and while it has sufficient power, the inverter transmits the signal to the smart main breaker indicating that it will be going offline, and also provides enough reserve power so that the smart main breaker is able to process the message and then close the interconnect switch so that the home is reconnected to the grid. In other embodiments, the smart main breaker includes a battery, and the smart main breaker reconnects to the grid (by powering the motor to close the main breaker) while it has sufficient power to do so. Commissioning for Smart Main Breaker The following are embodiments of commissioning of the smart main breaker described herein. In some embodiments, the commissioning process described herein minimizes installation and commissioning steps, even in the face of a varied hardware ecosystem. Smart main breaker commissioning is the process by which a smart main breaker is installed into a home. This usually occurs at the same time as the installation of the ESS. One goal for this process is to proceed automatically with as little labor as possible. The smart main breaker microcontroller (e.g., microprocessor described above) may be powered in some or all of the following ways:1. Powered via a battery that is packaged within the smart main breaker2. Derive power from the AC voltage applied at the grid side of the smart main breaker (that is being used as an intelligent, controllable grid relay)3. Derive power from the AC voltage applied to the load side of the smart main breaker4. Powered via a hardwire from the ESS (which in some embodiments is accompanied by a hardwired comms link, such as CAN or ethernet). In some embodiments, when a new smart main breaker is installed, it is configured to:1. Associate with one or more ESS units on site. If communication is wireless, such as over WiFi, it should ensure that it is pairing only with an ESS that is connected to the “Load” side of the relay, and not pair with, for example, an ESS in an adjoining building. This pairing allows for the relay state (e.g., state of the main breaker) to be reflected, for example, in a smartphone app, measure home consumption data, and other user facing features. This may also include an authentication step.2. Exchange information with the ESS, which can include a FW (firmware) version, serial number, etc. for serviceability.3. Boot into an “open” state to ensure that if an ESS is currently connected to the load side, there is not a large inrush current when the device boots.4. In some embodiments, the smart main breaker is programmed for a configurable amperage rating. In some embodiments, unlike a conventional main breaker, the current rating of the intelligent main breaker (e.g., the trip current) may be configured, as it is defined in firmware. If a particular panel requires a 100 A breaker instead of a 200 A breaker, the same device can be used and configured to trip at an overcurrent condition equivalent to a 100 A breaker. In some embodiments, to associate the smart main breaker to the ESS, the device first boots into an “open” mode. If hardwired to the ESS, the association is automatic. If wireless, in some embodiments the smart main breaker connects to a wireless network formed by the ESS. After joining the wireless network, the ESS may then enter a “grid forming” mode whereby it powers the loads in the home (while the smart main breaker is still isolating the home from the grid). The smart main breaker can then measure the voltage on the load side of the breaker and report precise measurements of the frequency and voltage to the ESS. In some embodiments, this measurement is used as a form of authentication. If the ESS and smart main breaker agree on the frequency of the AC voltage, then it is certain that they are connected to the same electrical circuit. If they disagree, then in some embodiments, the ESS removes the smart main breaker from the wireless network. If they agree, then the ESS and the smart main breaker are considered “paired”. The ESS may vary the frequency or amplitude of the AC voltage to ensure agreement. An alternative embodiment of performing the above is to rely on PLC (powerline communications), although PLC may require costly electronics, and may be subject to failure in noisy environments. In some embodiments, after pairing, the smart main breaker then provides phase offset measurements between the measured AC voltage on the grid side and the AC voltage from the inverter. In some embodiments, the smart main breaker provides the phase offset via a message back to the ESS, and the ESS adjusts the phase until they are back in alignment. Smart Main Breaker Form Factor As will be shown in the examples below, embodiments of the smart main breaker herein are designed to accommodate existing breaker slots, so that they can be installed into existing breaker panels, with little to no modification of the existing main panels. As described above, the smart main breaker is designed or sized to fit within an existing panel, and plugs into one or more standard breaker slots of the panel. There is a significant amount of variation in existing main panels that have been installed in homes, with numerous different kinds of makes and models. In order for a main breaker to be used with a main panel, it is often required to be certified to be compatible with that main panel. Typically, the certification of breakers involves panel manufacturers certifying that a given main breaker is compatible with their panel, such that the breaker can be included or listed on their certification directory. In this case, instead of certification with a utility, before being used in a panel, the smart main breaker device described in would have to be certified with OEMs such as breaker OEMs, panel OEMs, etc. The intelligent main breaker described herein is designed or sized or constructed to be certified to be compatible with a large range of existing main panels. For example, the design of the physical shape or the form factor is determined to have the broadest compatibility with existing panels. As one example, an evaluation of panel manufacturers and different main breaker SKUs for the manufacturers for different amperage sizes is performed. For the most common form factors, the ones that also share physical shapes are also determined in order to arrive at a single form factor that has the greatest compatibility across panels (e.g., has the highest compatibility, not just for one panel manufacturer, but across multiple panel manufacturers). For example, all of the form factors for main breakers of different main panel brands, models, and amperage sizes are evaluated. The form factor that is both most common and easiest to manufacture is determined. For example, the most common form factor may not be for the most common panel. As one example, consider larger amperage sizes of 200 A, which is the most common main panel amperage size. Despite such a panel being the most common size, each manufacturer has approached the manufacturing of compatible 200 A breakers in a variety of different shapes. Instead, the most common form factors across all panels include 100 A and 125 A breakers that have conventional form factors of being two pole, one inch per pole, with a standard handle tie. That is, the 100 A to 125 A breaker is the most uniform form factor across panels. In some embodiments, the form factor of the intelligent main breaker is selected based on this analysis of breaker form factors and the panels that they are compatible with. For example, the most common industry standard form factor across all manufacturers that will fit the most panels is selected as one option for the form factor of the smart main breaker. For example, breakers from 15 A to 125 A across the four major breaker OEMs have form factors that are substantially the same. The analysis to determine what is the most compatible breaker form factor can be periodically performed over time, in case form factors for breakers shift. As one example, the smart main breaker is implemented around a design utilizing a one inch per pole, two pole breaker, with a form factor similar to that of a plug-on stab main breaker. In some embodiments, the smart main breaker is a multi-piece assembly, with a core trip assembly, with intelligence wrapped around it in a manner that allows the entire assembly to be fit everywhere that the integrated device is certified. The following is an example of a package or form factor for the smart main breaker described herein. As described above, in addition to including a main breaker for safety functionality, the smart main breaker includes various other componentry, such as controllable actuators, sensors, microcontroller, memory, communications, etc. Existing main breakers are typically quite full. Given the additional componentry of the smart main breaker, the smart main breaker will require more space for all of its components than what is typically found in an existing main breaker form factor. In some embodiments, to house all of the componentry of a smart main breaker, the smart main breaker packaging includes a first portion that has the form factor of an existing main breaker, and also includes a second “backpack” container portion, where the “backpack” container portion has the shell and sizing of an existing branch breaker. This allows the overall package to be plugged into the main breaker slot, as well as the adjacent branch breaker slot/spot. The following are embodiments of a smart main breaker that, while larger than a typical existing main breaker, is still able to be fit or placed into the same location of the existing main breaker being replaced. For example, the form factor of the smart main breaker allows the smart main breaker to be installed on the bus bar with other branch breakers. The smart main breaker is constructed such that in addition to occupying the same space of a typical main breaker, it also consumes an additional breaker slot. For example, the intelligence is packaged into a container that is constructed to fit into a free breaker slot. In this example, the smart main breaker has a package that takes up a main breaker slot and an adjacent branch breaker slot. For example, in some embodiments, for the smart main breaker, the selected breaker form factor is duplicated, where some of the components are piggybacked onto the selected breaker form factor in a “backpack” portion. For example, if a typical hundred-amp breaker is two inches wide, taking up two spaces, then a container is added or attached as part of the overall smart main breaker package that is also an inch wide, with space for the intelligence, communications, etc. This results in a three-inch wide package that takes up three spaces (main breaker slot, which is often two spaces, along with an adjacent branch breaker slot). In this example, the smart main breaker has the form factor of a main breaker with an additional container (aforementioned “backpack”) for all of the additional componentry needed to implement the smart main breaker. FIGS.3and4illustrate embodiments of locations in an existing panel in which embodiments of the smart main breaker described herein may be installed. FIG.3illustrates an example of a location for installation of a smart main breaker. In this example, the portions of a panel that a smart main breaker slots into are shown. For example, suppose that the smart main breaker has the form factor of a standard hundred-amp main breaker form factor, where the form factor is augmented or piggybacked with a container that has a form factor of another branch breaker so that it occupies both the main breaker slot (302), as well as the branch breaker slot (304) adjacent to the main breaker slot. One example of a 100 A or 125 A version of a smart main breaker takes up the existing two slots in the panel for main breakers, with the piggyback container portion occupying the branch breaker slot adjacent to the main breaker slot. A typical panel includes a space for a main breaker, as well as spaces for branch breakers. For example, a standard 125-amp breaker takes up two breaker slots/spaces. In some embodiments, the housing of a smart main breaker is constructed to take up the space of an existing main breaker, as well as an adjacent branch breaker space. For example, the package of the smart main breaker is sized to occupy the main breaker slot and an adjacent branch breaker slot. The smart main breaker packaging includes terminals and fasteners to fit into the main breaker slots and adjacent branch breaker slot. That is, as shown in this example, the smart main breaker is sized to take up the main breaker slot in the panel, as well as consume an adjacent branch breaker slot so that the packaging of the smart main breaker includes sufficient space for all of the componentry to allow the smart main breaker to not only function as a main breaker for safety purposes, but also as a controllable grid interconnect relay, while also being able to plug into the slots of existing panels. FIG.4illustrates an example of a location for installation of a smart main breaker. In this example, installation of a 200 A main breaker is described. As one example, the new smart main breaker plugs into the existing slots402allocated for a 200 A main breaker, where additional space for intelligence would be included in portions of the smart main breaker packaging that fit or slot or plug into adjacent branch breaker slots (e.g., one or both of the adjacent branch breaker spaces404and406—the smart main breaker may also be sized so that it occupies other sets of branch breakers adjacent to the main breaker slot). In some embodiments, a 200 A main breaker is implemented by using two 100 A smart breakers. The example ofFIG.4shows a customer's existing panels, as wired. At404and406are examples of branch breakers, such as 20 A branch breakers. The branch breakers404and406are in the spaces adjacent to the main breaker slot402. In this example, there is a breaker in each of the adjacent 20 A branch breaker slot. During installation, if that slot is not available, an electrician can free up the adjacent breaker space so that the smart main breaker can consume or occupy the existing main breaker space in the panel, as well as the adjacent branch breaker space that is next to the main breaker slot. As one example, a larger 150 A or 200 A version of the smart main breaker includes a portion that takes up four breaker spaces, with a two-space piggyback or “backpack”. In some embodiments, the smart main breaker is implemented as a one-piece design that includes all of the componentry, and that plugs into the breaker panel (e.g., into the main breaker slots and adjacent branch breaker slots) as a single unit. In some embodiments, the smart main breaker is implemented as a plug on breaker. The smart main breaker is installed onto the bus bar stabs of the main panel. When installing, the installer wires the grid connection, as well as the communication connection to the intelligent onsite power source. As described herein, having a smart main breaker that is sized to utilize adjacent breaker slots provides the ability to take an existing form factor and grow it in a dimension that allows the smart main breaker to incorporate the componentry for implementing smart grid interconnect relay functionality, while still being able to be installed in an existing electrical panel. Modular Intelligent Main Breaker As one example, the controllable breaker is modular and may be constructed as multiple pieces. One piece for example is a standardized core component. Other pieces include adapters (e.g., cases) attached to the core component to create breakers of varying sizes and shapes to accommodate different types of breaker slots. This allows variable sized controllable main breakers to be created for various types of situations (where breakers may be of various shapes and sizes, with different amperage ratings). The following is an example of a controllable main breaker that includes a core component. Existing breakers in the United States typically have two input terminals and two output terminals (to break line 1 and line 2 in a 240V system). The modular controllable breaker design described herein may be used or adapted to create a controllable breaker that matches various aspects of the existing breaker that is being replaced, such as matching mounting features (e.g., how the breaker mounts into the breaker panel), shapes, terminal locations, etc. As one example, consider a 200 A controllable main breaker. The controllable main breaker includes a core component, where the core component includes the common functionality used to function as a main breaker as well as to be controllable. For example, the core component includes the componentry of the architecture described in conjunction withFIG.2. The core component may be of a size that fits within the envelope of existing 200 A controllable breakers to be replaced. For example, existing breakers may be overlaid to determine the intersection of common space. This may be used to determine the dimensions of the core component/package (other core component dimensions may be determined by performing similar analysis of existing breakers to be replaced or breaker slots to be filled). In some embodiments, the core component or unit includes terminals, which will be used to attach to adapters to generate particular instances or variations of controllable breakers. For example, to produce an individual version of a controllable main breaker (e.g., to replace a specific existing main breaker), the core component is augmented with an additional piece (e.g., plastic component), where the additional piece makes up the difference between what the overall main breaker form factor should be and what the core is. In some embodiments, the added piece includes terminals that make contact with the input/output terminals of the core component. This results in a modular controllable main breaker design. In some embodiments, a specific variation of a controllable main breaker is generated by coupling an adapter to the core component. As one example, an adaptor piece may be snapped on to a core component, where there are different adapters for different types of desired main breaker forms. As another example, a specific instance of a controllable breaker is generated by adding to molding. For example, different molds may be created around the core component. The modular nature of the controllable main breaker described above provides manufacturing benefits. For example, different cases may be created with different terminals embedded in them that electrically connect to the terminals of the core component. The core component may snap into the case, transforming it into a desired main breaker form factor/implementation. In this example, there is a standardized core that may be transformed into various different types of breakers via adaptors, additional molding, etc. In some embodiments, the cases are designed to match various aspects or features of the existing breakers to be replaced. For example, the case may be designed to fill the slot or receptacle that is normally filled by an existing breaker. Using such a modular controllable main breaker design, a controllable main breaker instance may be created to replace an existing main breaker by simply swapping out the existing main breaker with the new one that has been created to be of the same form. In this way, a controllable main breaker (that can also be used as a grid interconnect relay) can be installed without requiring installation of a new panel (which would involve moving loads over, inserting relays, etc.). The use of a standardized or common core component provides simplicity in certification as well. For example, one aspect of UL certification is failure mode analysis. In this example, as multiple variants of controllable main breakers may be created starting from a base core component, only the standardized core component (which includes the functional components in various embodiments) need be tested or analyzed. Similar efficiencies in thermal testing may also be realized using such a modular controllable main breaker design. In this example, the standardized core component is a single package that includes the same set of electronics or components that is common across the various breaker variations. This allows more efficient and faster (re)certification of controllable main breakers. As shown in these examples, there is a common core component that encompasses common functionality and hardware that may be included in every design variation. In some embodiments, the electronics for controlling the triggering (e.g., opening) of the contacts in the breaker, as well as closing/resetting of the main breaker may be external to the core component/breaker component. For example, wires from the controllable solenoid may come out of the main breaker/core component, which connect to an external controller. The controller may then put voltage on the wires to trigger the actuating mechanisms described above. Such electronics may be placed in the external unit in the event that there is not sufficient space within the portion of the main breaker that goes into a main breaker slot. For example, in some embodiments, the controllable main breaker includes the additional trigger mechanism, motor (e.g., for resetting the breaker after it is opened), an interlocking mechanism as described above, a mechanism for resetting the interlock, as well as other associated electronics. The external unit may then include, for example, additional processing logic, communications (e.g., powerline communications, WiFi componentry, etc.), etc., with a set of wires that go between the controllable main breaker component and the external unit. In some embodiments, the mechanisms for controlling the opening/closing of the main breaker as a grid interconnect relay are designed to not interfere with the safety functioning of the main breaker (e.g., so that the main breaker can still open in the event of thermal faults or short circuits). In some embodiments, the motor for resetting the main breaker on demand is also external to the main breaker core component. As one example, after a replacement main breaker is wired into the breaker panel, and before the door of the main breaker panel is closed, a unit is installed on top of the main breaker or portion of the main breaker in the main breaker slot, where this unit includes the motor reset mechanism. In some embodiments, the third or additional controllable trigger mechanism (e.g., solenoid) may also be external to the main body or core of the main breaker. The controllable trigger mechanism may act, for example, as a type of push button that behaves as a manual trip. As one example, the replacement breaker core may include a button that may be toggled or actuated, such as a push button. A controllable solenoid and motor accessory may then be placed on the outside of the main breaker component, over the button. The controllable external motor accessory may then actuate the button on the breaker core component. Such an implementation may be used in space constrained scenarios. For example, suppose that a manual shutoff button was included in the replacement breaker, but there is not sufficient space to include a solenoid that could actuate the button. In some embodiments, the solenoid is placed in an external unit, where the solenoid is configured to push that button. Similarly with the motor, if there is insufficient space within the main breaker that goes in the slot (or slots), a user input or control that a user may toggle or actuate may be included in the main breaker component that fits within the slot, where the main breaker component is augmented with an external motor accessory that actuates the control (e.g., physical button or lever). Retrofit Robotic Accessory The following are additional embodiments of a controllable main breaker that also functions as a grid interface relay. Existing main breakers are designed to be difficult to sabotage or be defeated by a user. For example, even if a user attempts to hold a lever closed (to keep the circuit closed), if a fault occurs (e.g., due to a thermal fault or high current due to a short circuit event), the main breaker will still open the circuit. That is, regardless of how the user is manipulating an external reset lever or button, the main breaker will trigger in the event of a fault for safety purposes. Further, with existing main breakers, in some cases, after tripping, the lever for the breaker goes to a middle position. If the user pushes on the lever towards the on position, they are not able to turn the breaker on. Rather, the user must first switch the breaker to off and then pull it back on. Even if a person is holding the main breaker lever in the on position, internally, the main breaker will still be able to trigger due to a fault. That is, a person cannot force the main breaker to stay on by jamming the lever to one side. Within the main breaker, the main breaker mechanism will open the contacts regardless of the position of the lever. In some embodiments, the controllable main breaker is implemented by implementing an actuator accessory or unit such as a robotic actuator device that goes over or otherwise augments or manipulates an existing main breaker, where the robotic device is configured, for example, to actuate the existing lever or button of the existing breaker. In this example, the existing breaker is able to maintain safety using the above-mentioned safety mechanisms even if the robotic device is not working properly. For example, even if the robotic device were malfunctioning and attempted to hold the breaker open, the robotic device would not be able to prevent the main breaker from opening due to a fault, as the main breaker will be able to open if needed, even if the robotic device is holding the lever in the on direction. In some embodiments, the robotic device includes a spring-loaded mechanism that is able to snap the lever or push-button mechanism of the main breaker to the off position very quickly (opening the interface to the meter, thereby disconnecting the home from the grid). Turning back on of the main breaker (and allowing current to flow again) need not be as aggressive (e.g., a slower, more motorized action may be used to push a lever on). Here, the robotic device can both turn on and off an existing breaker. By using such a robotic device, controllability may be added to any main breaker, without having to uninstall that existing main breaker. In some embodiments, any additional hardware for introducing controllability is included in the external robotic device, which is placed over an existing main circuit breaker. In some embodiments, the robotic device is low profile so that after installation, the door of the circuit breaker panel can still be closed. As shown in these examples, controllability of the main breaker (to make it into a controllable grid interconnect relay) is added without having to design a new type of main breaker, and UL certification would not need to be performed (or may otherwise be simplified). In some embodiments, the robotic device receives power by connecting the robotic device to wires that run out of the panel (e.g., through a conduit), allowing the robotic device to tap into whatever voltage it needs. In other embodiments, the breaker includes tunnels in the plastic of the breaker, such that wires can be run through the surface of the breaker and end up inside of the box. In other embodiments, rather than having wires that pass through the plastic of the breaker, a replacement breaker may be introduced that includes a plug or receptacle on its face. The robotic device may then plug directly into the connector or terminal or receptacle presented on the front surface of the main breaker. In this way, when plugged in, anything needed by the robotic device may be passed from inside the box, such as line 1 and line 2 voltage. In some embodiments, the main breaker with the receptacle, as well as the robotic actuator, are made touch-safe. Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed embodiments are illustrative and not restrictive. | 76,159 |
11862963 | DETAILED DESCRIPTION The subject matter of embodiments of the present disclosure is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. Certain aspects and examples of the disclosure relate to redundant overvoltage protection systems and methods used to control application of power to a generator excitation field of a power generation system that is used to power an electrical system. The generator excitation field may be a component of a power generator. The power generator may be used to provide power to an electrical system, such as an aircraft electrical system. The redundant overvoltage protection system may be operated to prevent prolonged exposure of the electrical system to an overvoltage event of the generator. For example, the generator may experience an overvoltage fault condition. Upon detection of the overvoltage fault condition, the redundant overvoltage protection system may provide redundant techniques to remove application of overvoltage power to the electrical system. To improve a likelihood that an overvoltage protection system will detect and act on the overvoltage condition of the generator, the redundant overvoltage protection system provides multiple detection and power isolation redundancies. For example, the overvoltage condition may be measured at multiple locations (e.g., at an output of the generator and at a point of regulation of the generator). Further, the redundant overvoltage protection system may disconnect a generator excitation field of the generator from a power source at multiple locations along a path between the power source and the generator excitation field. Such redundancies provide multiple dissimilar protection paths for overvoltage protection of the electrical system. The described embodiments provide a redundant overvoltage protection system that controls a power output of a generator to an electrical system during an overvoltage event. While the redundant overvoltage protection system is discussed generally for use with an aircraft electronics system, it is by no means so limited. Rather, embodiments of the redundant overvoltage protection system may be used with electrical systems of any type or otherwise as desired. FIG.1is a schematic diagram of a redundant overvoltage protection system100used to control application of power to a generator excitation field102. The overvoltage protection system100receives an input signal104from a power source (not shown) and supplies the input signal104to the generator excitation field102of a generator106when a voltage generated by the generator106is less than an overvoltage threshold set by the overvoltage protection system100. For example, the overvoltage protection system100may limit providing power from the input signal104to the generator excitation field102during an overvoltage event of the generator106to limit negative effects on an electrical system108due to the overvoltage event. By not providing power from the input signal104to the generator excitation field102, a voltage output to the electrical system108by the generator106is reduced below the overvoltage threshold because the generator106is no longer generating power due to a lack of excitation at the generator excitation field102. Thus, the overvoltage protection system100may be referred to as a deenergizing circuit due to the removal of a power source (i.e., the input signal104) from the generator excitation field102that results in deenergizing the generator106. As illustrated, the overvoltage protection system100includes two signal disconnect points capable of disconnecting the input signal104from the generator excitation field102. A solid-state switch110, which may be a p channel metal-oxide-semiconductor field-effect transistor (MOSFET) or any other suitable solid-state switch, may provide a first disconnect point between the input signal104and the generator excitation field102. Additionally, a generator excitation field relay112(i.e., the field relay112) may provide a second disconnect point between the input signal104and the generator excitation field102. The field relay112may be any type of electrically operated switch capable of closing during normal operation of the generator106and opening during a detected fault condition. Overvoltage faults may be detected at multiple voltage detection locations. For example, a point of regulation voltage, which may be a voltage received by a generator control unit within the electrical system108or within another electrical system coupled to the generator106, may be detected by a voltage sensor109and used as the voltage detection location to determine an overvoltage fault. In an example, a backup voltage detection location may also be used. The backup voltage detection location may be a voltage measured by a voltage sensor111directly at an output of the generator106. Other voltage detection locations associated with the generator106may also be used to determine an overvoltage event. The backup voltage detection location (e.g., at the output of the generator106) may provide a voltage that is slightly higher than the point of regulation voltage received at the generator control unit (e.g., due to a voltage drop across feeder cables between the generator106and the point of regulation). Accordingly, the overvoltage threshold for a voltage measured at the backup voltage detection location may be a corresponding amount higher than the overvoltage threshold associated with the point of regulation voltage. An overvoltage value detected at either the point of regulation or the backup voltage detection location may result in disconnecting the input signal104from the generator excitation field102. When a signal or other connection is lost between the overvoltage protection system100and the point of regulation, a signal from the backup voltage detection location may still provide an indication of an overvoltage condition at the generator106. Thus, an overvoltage fault provided to the electrical system108may be avoided provided that the overvoltage protection system100receives data associated with a point of regulation voltage signal and a backup voltage detection location voltage signal. The signals from the point of regulation and the backup voltage detection location may be provided to or converted by the overvoltage protection system100into a Boolean value of 0 or 1 depending on whether the signals are below or exceed an overvoltage threshold. Other faults associated with the generator106may also be fed to the overvoltage protection system100. For example, an overheating indication, a short indication, voltage regulation disable condition indications, power supply failure event indications, or any other faults associated with the generator106or the electrical system108may be provided to the overvoltage protection system100to initiate removal of the input signal104to the generator excitation field102. Boolean values associated with the fault indications, both overvoltage faults and otherwise, are provided to fault inputs114,116,118, and120. More or fewer fault inputs114-120are contemplated within the scope of the present disclosure. Two of the fault inputs114and116may be associated with a point of regulation overvoltage determination and a backup voltage detection location overvoltage determination, respectively. The additional fault inputs118and120may be associated with any other detectable faults that may benefit from removal of the input signal104to the generator excitation field102(e.g., temperature of the generator106, other health indicators of the generator106, health indicators of the electrical system108, etc.). The fault inputs114-120may be provided as Boolean values from the generator control unit associated with the generator106. For example, the generator control unit may receive measurements indicative of a fault and convert the measurements to a Boolean value that is provided to the fault inputs114-120. In another example, the overvoltage protection system100may receive data signals representing the point of regulation voltage or the backup voltage detection location voltage and convert the received data to a Boolean value that is provided to the fault inputs114-120. The fault inputs114-120are provided to a NOR logic gate122. The NOR logic gate122provides a high signal to a base123of a solid-state switch124, which may be an NPN bipolar transistor or other solid-state switching device, when the fault inputs114-120are all at a low value (e.g., no fault is present at any of the fault inputs114-120). The high signal provided to the solid-state switch124turns the solid-state switch to an on state, which enables passage of current to ground126. If any or all of the fault inputs114-120have a high value (e.g., indicating that a fault is present), the NOR logic gate122provides a low signal to the base123, and the solid-state switch124transitions to an off state. The off state of the solid-state switch124removes a path for the current to flow to the ground126. While the NOR logic gate122is depicted inFIG.1, other logic gates may also be used in place of the NOR logic gate122. For example, an AND logic gate may be used in place of the NOR logic gate122if signals indicating faults are provided to the fault inputs114-120as low signals. In such an example, any low input, which indicates a fault, to the fault inputs114-120may result in the solid-state switch124transitioning to an off state. The solid-state switch124may control operation of the solid-state switch110. For example, the p-channel MOSFET depicted as the solid-state switch110may enter a saturation mode (i.e., a fully on state) when two conditions are met. The first condition is that a voltage differential between a source128and a gate130of the solid-state switch124is greater than an absolute value of a threshold voltage of the solid-state switch124. The second condition is that a voltage differential between the source128and a drain132of the solid-state switch124is greater than the voltage differential between the source128and the gate130less the absolute value of the threshold voltage of the solid-state switch124. The solid-state switch124in an on state may enable a voltage drop across resistor134that is sufficient to meet the voltage differential between the source128and the gate130of the solid-state switch110for the solid-state switch110to operate in a saturation mode. Operation of the solid-state switch110in the saturation mode may result in the solid-state switch110functioning as a closed switch that enables the input signal104to traverse the solid-state switch110. When the fault inputs114-120all provide a low signal to the NOR logic gate122(i.e., there are no detected faults), the solid-state switch124remains in an on state resulting in the solid-state switch110also remaining in an on state. If one or more of the fault inputs114-120provide a high signal to the NOR logic gate122(i.e., a fault is detected), then the solid-state switch124transitions to an off state. The off state of the solid-state switch124removes a path for current associated with the input signal104to travel to the ground126. Because the path to the ground126is removed, the gate130of the solid-state switch110becomes floating. Therefore, the voltage differential between the source128and the gate130is zero, and the solid-state switch operates in a cut-off mode. The cut-off mode indicates that the solid-state switch110no longer provides a path along which the input signal104is able to traverse. That is, the solid-state switch110functions as an open circuit. Thus, upon any indication of a fault received at the fault inputs114-120, the solid-state switch110will remove application of the input signal104to the generator excitation field102. A bidirectional transient-voltage-suppression (TVS) diode136may be positioned in parallel with the resistor134. The bidirectional TVS diode136may acknowledge an overvoltage condition at the source128of the solid-state switch110by shunting excess current when the overvoltage condition exceeds an avalanche breakdown potential of the bidirectional TVS diode136and thus protecting the gate130of the solid state switch110. The bidirectional TVS diode136may be chosen to correspond with an overvoltage threshold of the electrical system108. That is, the bidirectional TVS diode136may prevent or limit damage to the solid state switch110during the overvoltage condition when the input signal104provided to the generator excitation field102results in an output voltage of the generator106provided to the electrical system108that exceeds the overvoltage threshold of the electrical system108. The bidirectional TVS diode136may respond to the overvoltage condition in a manner quicker than the solid-state switches110and124. However, extended overvoltage events experienced by the bidirectional TVS diode136may result in failure of the bidirectional TVS diode136. Thus, the solid-state switches110and124may react to the overvoltage event prior to failure of the bidirectional TVS diode136. By removing the input signal104from the generator excitation field102with the solid-state switch110, the field relay112may be opened with minimal potential for the field relay112to weld in a closed position due to an arc created during an attempt to open the field relay112. Thus, the field relay112may be opened upon detection of an overvoltage fault after the solid-state switch110transitions to the cut-off mode to provide a redundant disconnect location between the input signal104and the generator excitation field102. When the overvoltage condition lapses, the field relay112and the solid-state switch110may both transition to a conductive state to recommence conducting the input signal104to the generator excitation field102. FIG.2is a schematic diagram of an additional redundant overvoltage protection system200used to control application of power to a generator excitation field. The redundant overvoltage protection system200includes the components of the redundant overvoltage protection system100with an additional layer of redundancy provided by a blocking circuit202. The blocking circuit202is tuned to block provision of the input signal104to the generator excitation field102at a solid-state switch204, which may be a p-channel MOSFET or any other suitable switching device, using analog control when the input signal104induces the generator106to output a voltage to the electrical system108that exceeds an overvoltage threshold of the electrical system108. To accomplish blocking provision of the input signal104to the generator excitation field102, the blocking circuit202includes a solid-state switch206, a diode208, and resistors210and212. The solid-state switch206, which may be a PNP BJT transistor or any other suitable solid-state switch, conducts from an emitter214to a collector216when a signal supplied to a base218of the solid-state switch206is low. Further, the solid-state switch206is a near ideal insulator between the emitter214and the collector216when the signal supplied to the base218is high. That is, when the voltage applied to the base218is too similar to a voltage applied to the emitter214, the solid-state switch206does not transmit current from the emitter214to the collector216(e.g., the solid-state switch206is in an off state). Alternatively, when the voltage applied to the base218is a threshold amount less than the voltage applied to the emitter214, the solid-state switch206conducts current from the emitter214to the collector216(e.g., the solid-state switch206is in an on state). To establish when the solid-state switch206transitions between the on state and the off state, the diode208is positioned between the base218and the ground126. The diode208, which may be a PN junction diode, a Zener diode, or any other type of diode, may have a breakdown voltage or Zener voltage tuned to a voltage level of the input signal104provided to the generator excitation field102that generates an overvoltage condition output by the generator106to the electrical system108. For example, when the overvoltage rating of the electrical system108is 28V, the diode208may be selected based on a breakdown voltage or a Zener voltage of the diode208that is equal to a voltage of the input signal104that induces the overvoltage output at the generator106. When the input signal104has a voltage that is less than the breakdown or Zener voltage of the diode208, the solid-state switch206may be in an off state. Because the solid-state switch206is in an off state, a voltage at the collector216of the solid-state switch206is equal to ground. Accordingly, a voltage applied to a gate220of the solid-state switch204is ground, and the solid-state switch204is conductive from a source222to a drain224of the solid-state switch204. When the input signal104has a voltage that is greater than the breakdown or Zener voltage of the diode208, the solid-state switch206may be in an on state. Because the solid-state switch206is in an on state, a voltage at the collector216of the solid-state switch206is equal to a voltage at the emitter214of the solid-state switch206less a small voltage drop associated with the solid-state switch206. Accordingly, a voltage applied to the gate220of the solid-state switch204is a high signal, and the solid-state switch204blocks conductivity from the source222to the drain224of the solid-state switch204. Thus, the blocking circuit202is able to automatically block provision of the input signal104to the generator excitation field102when the input signal104is likely to induce an overvoltage event at the generator106. Similar to the overvoltage protection system100discussed above with respect toFIG.1, the overvoltage protection system200includes two additional signal disconnect points capable of disconnecting the input signal104from the generator excitation field102. The solid-state switch110may provide the first additional disconnect point between the input signal104and the generator excitation field102. Additionally, the field relay112may provide the second additional disconnect point between the input signal104and the generator excitation field102. The field relay112may be any type of electrically operated switch capable of closing during normal operation of the generator106and opening during a detected fault condition. Overvoltage faults may be detected at multiple voltage detection locations. For example, a point of regulation voltage, which may be a voltage received by a generator control unit within the electrical system108or other electrical system coupled to the generator106, may be detected by the voltage sensor109and used as the voltage detection location to determine an overvoltage fault. In an example, a backup voltage detection location may also be used. The backup voltage detection location may be a voltage detected by the voltage sensor111and measured directly at an output of the generator106. Other voltage detection locations associated with the generator106may also be used to determine an overvoltage event. The backup voltage detection location (e.g., at the output of the generator106) may provide a voltage that is slightly higher than the point of regulation voltage received at the generator control unit (e.g., due to a voltage drop across feeder cables between the generator106and the point of regulation). Accordingly, the overvoltage threshold for a voltage measured at the backup voltage detection location may be a corresponding amount higher than the overvoltage threshold associated with the point of regulation voltage. The signals from the point of regulation and the backup voltage detection location may be provided to or converted by the overvoltage protection system200as a Boolean value of 0 or 1 depending on whether voltages of the signals are below or exceed an overvoltage threshold. Other faults associated with the generator106may also be fed to the overvoltage protection system200. For example, an overheating indication, a short indication, voltage regulation disable condition indications, power supply failure event indications, or any other faults associated with the generator106or the electrical system108may be provided to the overvoltage protection system100to initiate removal of the input signal104to the generator excitation field102. Boolean values associated with the fault indications, both overvoltage faults and otherwise, are provided to the fault inputs114,116,118, and120. More or fewer fault inputs114-120are contemplated within the scope of the present disclosure. Two of the fault inputs114and116may be associated with a point of regulation overvoltage determination and a backup voltage detection location overvoltage determination, respectively. The additional fault inputs118and120may be associated with any other detectable faults that may be resolved or alleviated by removing the input signal104from the generator excitation field102. The fault inputs114-120are provided to the NOR logic gate122. The NOR logic gate122provides a high signal to the base123of the solid-state switch124, which may be an NPN BJT or other solid-state switching device, when the fault inputs114-120are all at a low value (e.g., no fault is present at any of the fault inputs114-120). The high signal provided to the solid-state switch124turns the solid-state switch to an on state, which enables passage of current to the ground126. If any or all of the fault inputs114-120have a high value (e.g., indicating that a fault is present), the NOR logic gate122provides a low signal to the base123, and the solid-state switch124transitions to an off state. The off state of the solid-state switch124removes a path for the current to the ground126. While the NOR logic gate122is depicted inFIG.1, other logic gates may also be used in place of the NOR logic gate122. For example, an AND logic gate may be used in place of the NOR logic gate122if signals indicating faults are provided to the fault inputs114-120as low signals. In such an example, any low input, which indicates a fault, to the fault inputs114-120may result in the solid-state switch124transitioning to an off state. The solid-state switch124may control operation of the solid-state switch110. For example, the p-channel MOSFET depicted as the solid-state switch110may enter a saturation mode (i.e., a fully on state) when two conditions are met. The first condition is that a voltage differential between the source128and the gate130of the solid-state switch124is greater than an absolute value of a threshold voltage of the solid-state switch124. The second condition is that a voltage differential between the source128and the drain132of the solid-state switch124is greater than the voltage differential between the source128and the gate130less the absolute value of the threshold voltage of the solid-state switch124. The solid-state switch124in an on state may enable a voltage drop across the resistor134that is sufficient to meet the voltage differential between the source and the gate of the solid-state switch110for the solid-state switch110to operate in a saturation mode. Operation of the solid-state switch110in the saturation mode may result in the solid-state switch110functioning as a closed switch such that the input signal104is able to traverse the solid-state switch110. Accordingly, when the fault inputs114-120are all providing a low signal to the NOR logic gate122(i.e., there are no detected faults), the solid-state switch110may remain in an on position. If one or more of the fault inputs114-120provide a high signal to the NOR logic gate122(i.e., a fault is detected), then the solid-state switch124transitions to an off state. The off state of the solid-state switch124removes a path for current associated with the input signal104to travel to the ground126. Because the path to the ground126is removed, the gate130of the solid-state switch110becomes floating. Therefore, the voltage differential between the source128and the gate130is zero, and the solid-state switch operates in a cut-off mode. The cut-off mode indicates that the solid-state switch110no longer provides a path along which the input signal104is able to traverse to the generator excitation field102. That is, the solid-state switch110functions as an open circuit. Thus, upon any indication of a fault at the fault inputs114-120, the solid-state switch110will remove application of the input signal104to the generator excitation field102. The bidirectional TVS diode136may be positioned in parallel with the resistor134. In an example, the bidirectional TVS diode136detects an overvoltage condition at the source128of the solid-state switch110by shunting excess current when the overvoltage condition exceeds an avalanche breakdown potential of the bidirectional TVS diode136to protect the gate130of the solid state switch110. The bidirectional TVS diode136may be chosen to correspond with an overvoltage threshold of the electrical system108. That is, the bidirectional TVS diode136may prevent or limit damage to the solid state switch when the input signal104provided to the generator excitation field102results in an output voltage of the generator106that exceeds the overvoltage threshold of the electrical system108. The bidirectional TVS diode136may respond to the overvoltage condition in a manner quicker than the solid-state switches110and124. However, extended overvoltage events experienced by the bidirectional TVS diode136may result in failure of the bidirectional TVS diode136. Thus, the solid-state switches110and124may react to the overvoltage event prior to failure of the bidirectional TVS diode136. By removing the input signal104from the generator excitation field102with the solid-state switches110and204, the field relay112may be opened in a manner that avoids welding the field relay112in a closed position due to creation of an arc during an attempt to open the field relay112. Thus, the field relay112may be opened upon detection of an overvoltage fault after the solid-state switch110, the solid-state switch204, or both transition to the cut-off modes to provide a redundant disconnect location between the input signal104and the generator excitation field102. When the overvoltage condition lapses, the field relay112, the solid-state switch110, and the solid-state switch204may each transition to a conductive state to conduct the input signal104to the generator excitation field102. FIG.3is a flowchart of a process300for controlling the redundant overvoltage protection systems100and200. As discussed above, an overvoltage condition of an output of the generator106to the electrical system108may have negative effects on the operation of the electrical system108. Accordingly, the redundant overvoltage protection systems100and200provide functionality that detect and limit the overvoltage conditions from being generated by the generator106. At block302, the process300involves monitoring a point of regulation voltage that is input to a generator control unit of the electrical system108. As discussed above, the point of regulation voltage may be the voltage output by the generator106and used to power the electrical system108. The electrical system108may experience negative effects when the point of regulation voltage exceeds an overvoltage rating or threshold of the electrical system108. At block304, the process300involves monitoring an output voltage of the generator106. The output voltage of the generator106, which may be referred to as a backup point of regulation voltage, may be slightly higher than the point of regulation voltage because the output voltage of the generator106has not experienced a voltage drop associated with a resistance of power transmission lines from the generator106to the electrical system108. The output voltage of the generator106provides a redundant and dissimilar location for the redundant overvoltage protection systems100and200to monitor the generator106for overvoltage conditions. Other locations associated with the generator106may also be monitored for overvoltage conditions. At block306, the process300involves detecting an overvoltage fault at the point of regulation, at the output of the generator106, or both. Because the voltage at the output of the generator may be slightly greater than the actual voltage received at the electrical system108, the overvoltage measurement at the output of the generator106may take into account the expected slightly elevated voltage levels when determining whether there is an overvoltage condition. If an overvoltage condition is detected, a fault indication may be provided to the fault inputs114-120to control the solid-state switch110to remove the input signal104from the generator excitation field102. At block308, the process300involves opening the solid-state switch110in response to detecting the overvoltage fault. As mentioned above, the fault inputs114-120may provide a positive fault identification to the NOR logic gate122. With the positive fault identification, the solid-state switch124is opened. In opening the solid-state switch124, the solid-state switch110is also opened, which prevents provision of the input signal104to the generator excitation field102. Removal of the input signal104from the generator excitation field102prevents the excitation of the generator excitation field102and ultimately generation of power by the generator106. Accordingly, providing overvoltage power to the electrical system108is avoided. At block310, the process300involves opening the solid-state switch204in response to detecting an input signal104supplied to the generator excitation field102that is likely to induce an overvoltage fault at the point of regulation or the backup point of regulation. As discussed above, the blocking circuit202causes the solid-state switch204to open when a voltage of the input signal104exceeds a breakdown voltage or Zener voltage of the diode208. Accordingly, the diode208may be selected such that the breakdown voltage or the Zener voltage of the diode208is a voltage value provided by the input signal104to the generator excitation field102that induces an overvoltage output by the generator106. When the voltage value of the input signal104exceeds the breakdown voltage or the Zener voltage, the solid-state switch204automatically removes application of the input signal104to the generator excitation field102. It may be appreciated that, in an example, block308may be performed as part of the process300without also performing block310. Likewise, block310may be performed as part of the process300without also performing block308. As used herein, the term “opening,” as it relates to the operation of the solid-state switches110,124,204, and206, may refer to the solid-state switches operating in an off mode or cut-off mode. Similarly, the term “closing,” as it relates to the operation of the solid-state switches110,124,204, and206, may refer to the solid-state switches operating in a fully on state or a saturation mode. At block312, the process300involves opening the generator excitation field relay112in response to detecting the overvoltage fault. In an example, block312may be completed after block308, block310, or both are performed. For example, a possibility of inadvertently welding the field relay112in a closed position with an arc generated when the field relay112attempts to open is avoided by removing application of the input signal104to the generator excitation field102using the solid-state switches110and204. Thus, removing the input signal104prior to attempting to open the field relay112may result in greater reliability of the operation of the field relay112. In another example, the field relay112may be opened at any time upon detection of the overvoltage condition (e.g., before, during, or after opening the solid-state switches110and204). In such an example, the field relay112functions as an additional disconnect location for the application of the input signal104to the generator excitation field102when an overvoltage condition at the generator106is detected. Thus, the combination of the field relay112with the solid-state switches110and204provide multiple redundant disconnect locations to ensure the input signal104is removed from the generator excitation field102upon detection of the overvoltage event. In the following, further examples are described to facilitate the understanding of the subject matter of the present disclosure: As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., “Examples 1-4” is to be understood as “Examples 1, 2, 3, or 4”). Example 1 is a method, comprising: monitoring a point of regulation voltage input to a generator control unit; monitoring a generator output voltage as a backup point of regulation voltage input; detecting an overvoltage fault at the point of regulation voltage input, the backup point of regulation voltage input, or both; opening a first solid-state switch in response to detecting the overvoltage fault to prevent provision of an input signal to a generator excitation field; and opening a generator excitation field relay in response to detecting the overvoltage fault to prevent provision of the input signal to the generator excitation field. Example 2 is the method of example 1, further comprising: opening a second solid-state switch at a blocking circuit using analog control to prevent provision of the input signal to the generator excitation field, wherein the second solid-state switch is opened when a voltage of the input signal is above a voltage threshold that induces the generator output voltage to an overvoltage fault value. Example 3 is the method of example 2, wherein the blocking circuit comprises a diode tuned with a breakdown voltage or a Zener voltage equal to the voltage threshold, and a third solid-state switch is closed when the input signal exceeds the voltage threshold, wherein closing the third solid-state switch results in opening the second solid-state switch. Example 4 is the method of examples 1-3, further comprising: suppressing the input signal at a gate of the first solid-state switch using a transient-voltage-suppression diode when the input signal exceeds an avalanche breakdown potential of the transient-voltage-suppression diode. Example 5 is the method of examples 1-4, further comprising: receiving an indication of the overvoltage fault at a logic gate; and controlling a second solid-state switch to open using an output of the logic gate, wherein controlling the second solid-state switch to open results in the opening of the first solid-state switch. Example 6 is the method of examples 1-5, further comprising: opening the first solid-state switch in response to detecting an overheating fault. Example 7 is the method of examples 1-6, wherein the point of regulation voltage input to the generator control unit comprises a power signal provided to an electrical system of an aircraft. Example 8 is the method of examples 1-7, wherein opening the generator excitation field relay occurs after opening the first solid-state switch. Example 9 is the method of examples 1-8, wherein opening the first solid-state switch, opening the generator excitation field relay, or both result in deenergizing the generator excitation field. Example 10 is a system, comprising: a first voltage sensor configured to monitor a point of regulation voltage; a second voltage sensor configured to monitor a generator output voltage of a generator; a generator excitation field relay electrically coupled between a generator excitation field of the generator and a power source of the generator excitation field, wherein the generator excitation field relay is controllable to open when the first voltage sensor detects an overvoltage condition from the point of regulation voltage, the second voltage sensor detects an overvoltage condition from the generator output voltage, or both; a deenergizing circuit, comprising: a logic gate configured to receive one or more fault indication signals from the first voltage sensor, the second voltage sensor, or both; and a first solid-state switch configured to open when the logic gate receives at least one of the one or more fault indication signals, wherein opening the first solid-state switch results in deenergizing the generator excitation field. Example 11 is the system of example 10, comprising: a voltage blocking circuit configured to block application of a voltage output from the power source to the generator excitation field, wherein the voltage blocking circuit comprises: a second solid-state switch configured to open when the voltage output of the power source is above a voltage threshold that induces the generator output voltage to an overvoltage fault value. Example 12 is the system of example 11, wherein the voltage blocking circuit further comprises: a diode comprising a breakdown voltage or a Zener voltage equal to the voltage threshold; and a third solid-state switch configured to control the second solid-state switch to open when the voltage output of the power source exceeds the voltage threshold. Example 13 is the system of examples 10-12, wherein the logic gate comprises a NOR logic gate, and wherein the deenergizing circuit further comprises: a second solid-state switch controllable by an output of the NOR logic gate, wherein the second solid-state switch causes the first solid-state switch to open when the NOR logic gate receives one of the plurality of fault indication signals. Example 14 is the system of examples 10-13, wherein the deenergizing circuit further comprises a transient-voltage-suppression diode tuned to suppress an overvoltage condition at a source of the first solid-state switch. Example 15 is the system of examples 10-14, wherein the plurality of fault indication signals represent indications of faults associated with overvoltage events, overheating events, voltage regulation disable conditions, or power supply failure events. Example 16 is a method, comprising: monitoring a point of regulation voltage input to a generator control unit; monitoring a generator output voltage as a backup point of regulation voltage input; detecting an overvoltage fault at the point of regulation voltage input, the backup point of regulation voltage input, or both; opening a first solid-state switch at a blocking circuit using analog control to prevent provision of an input signal to a generator excitation field, wherein the first solid-state switch is opened when a voltage of the input signal is above a voltage threshold that induces the generator output voltage to an overvoltage fault value; and opening a generator excitation field relay in response to detecting the overvoltage fault. Example 17 is the method of example 16, wherein opening the first solid-state switch, opening the generator excitation field relay, or both result in deenergizing the generator excitation field. Example 18 is the method of examples 16-17, wherein the blocking circuit comprises a diode tuned with a breakdown voltage or a Zener voltage equal to the voltage threshold, a second solid-state switch is closed when the input signal exceeds the voltage threshold, and closing the second solid-state switch results in opening the first solid-state switch. Example 19 is the method of examples 16-18, wherein opening the generator excitation field relay occurs after opening the first solid-state switch. Example 20 is the method of examples 16-19, wherein the point of regulation voltage input to the generator control unit comprises a power signal provided to an electrical system of an aircraft Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and sub-combinations are useful and may be employed without reference to other features and sub-combinations. Embodiments of the present subject matter have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present disclosure is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications may be made without departing from the scope of the claims below. | 40,983 |
11862964 | DETAILED DESCRIPTION FIG.1is a block diagram of a universal serial bus (USB) device100according to an example embodiment.FIG.2is a block diagram of an example of a USB receptacle110ofFIG.1, according to an example embodiment. Referring toFIG.1, the USB device100may be an arbitrary, i.e., any, device capable of communicating with another device through a USB interface. For example, the USB device100may be a stationary device, e.g., a desktop computer, a server, and the like, or a portable device, e.g., a laptop computer, a mobile phone, a tablet personal computer (PC), and the like. Also, the USB device100may be a component included in the stationary device or the portable device and configured to provide the USB interface. As shown inFIG.1, the USB device100may include a USB receptacle110, a termination circuit120, a port controller130, a power circuit140, and an overvoltage protection (OVP) circuit150. The USB receptacle110may be coupled to a USB cable or a USB plug to be connected to another USB device. The USB receptacle110may include a plurality of exposed pins that transmit and receive signals or transmit power. For example, as shown inFIG.2, the USB receptacle110may include pins to transmit transmission signals TX+ and TX−, receive receiving signals RX+ and RX−, channel configuration (CC) signals CC1and CC2, a VBUS voltage V_BUS, and a ground voltage. In some embodiments, the USB receptacle110may have a USB Type-C pin arrangement as shown inFIG.2. When a conductive foreign material is introduced into the USB receptacle110while the USB plug is not coupled to the USB receptacle110or an electrical short occurs in the USB cable coupled to the USB receptacle110, at least two pins of the USB receptacle110may be electrically connected to each other. The pins that are inappropriately electrically connected to each other may cause leakage currents, which may not only cause a communication failure via the USB interface but also may cause damage to the USB device100or the other USB device. In particular, when the USB device100is a portable device or a component included in the portable device, a conductive material (e.g., water, metal, and the like) may be easily introduced into the USB receptacle110. Thus, excessive power consumption or damage may occur in the USB device100. For example, USB power delivery (PD) may define delivery of a high power (e.g., 20 V and 5 A) via a VBUS pin (e.g., A4ofFIG.2). Also, when the VBUS pin has a short circuit with another pin (e.g., A5ofFIG.2), a high voltage and current of the VBUS pin may be applied to the shorted pin. To protect an internal circuit (e.g., the termination circuit120and the port controller130) of the USB device100from the high voltage and current, the USB device100may include the OVP circuit150. The OVP circuit150may detect an overvoltage occurring at a pin included in the USB receptacle110and may electrically disconnect the pin from the internal circuit of the USB device100when an overvoltage is detected. Also, the OVP circuit150may output an activated detection signal DET when the overvoltage is detected. In some embodiments, the OVP circuit150may not attenuate signals transmitted and received via the pins of the USB receptacle110in a normal state in which an overvoltage does not occur. The OVP circuit150may include a circuit that consumes relatively high power. The USB device100may operate in a normal mode and a low-power mode. The OVP circuit150may reduce power consumption of the USB device100in the low-power mode. Hereinafter, as described below with reference to the drawings, the OVP circuit150may provide reduced power consumption in the low-power mode without causing the attenuation of the signals in the low-power mode. The termination circuit120may be controlled by the port controller130and provide the USB receptacle110with termination in accordance with USB requirements. For example, the termination circuit120may transmit CC signals CC1and CC2from the port controller130to the USB receptacle110or transmit the CC signals CC1and CC2from the USB receptacle110to the port controller130, under control of the port controller130. Also, the termination circuit120may provide a VCONN voltage for providing power for an active cable from the power circuit140to the USB receptacle110under control of the port controller130. The port controller130may communicate with the termination circuit120, control the termination circuit120, and control the USB interface in response to signals received through the termination circuit120. The port controller130may control port power supplied to the outside or received from the outside through the USB receptacle110, and process the CC signals CC1and CC2according to USB requirements. In some embodiments, the port controller130may be a logic block designed by logic synthesis, a software block included in a memory that stores a processor and instructions executed by the processor, or a combination thereof. In some embodiments, the port controller130may be referred to as a power delivery integrated circuit (PDIC). In some embodiments, the termination circuit120and the port controller130may be included in one IC, and the IC may be referred to as a PDIC. The port controller130may output a power control signal PWR for controlling the power circuit140. For example, the port controller130may perform power negotiation with another USB device and control the power circuit140using the power control signal PWR based on the negotiation result. In some embodiments, the port controller130may provide a mode signal MD indicating the normal mode or the low-power mode to the OVP circuit150, and may receive a detection signal DET indicating whether an overvoltage has occurred from the OVP circuit150. The port controller130may switch a mode between the normal mode and the low-power mode based on a user's input to the USB device100or switch a mode between the normal mode and the low-power mode when an entry condition to the normal mode or the low-power mode is satisfied, and generate the mode signal MD indicating a mode. In some embodiments, when an overvoltage occurs, i.e., when an activated detection signal DET is received from the OVP circuit150, the port controller130may control a signal generator (e.g., a speaker, a display, a light-emitting element, a vibration motor, and so forth) to notify occurrence of an overvoltage to the outside of the USB device100, for example, to output a signal that is recognizable, i.e., detectable, by a user of the USB device100. The power circuit140may provide a VBUS voltage V_BUS to the USB receptacle110or receive the VBUS voltage V_BUS from the USB receptacle110. In some embodiments, when the USB device100supports an upload faced port (UFP), the power circuit140may receive the VBUS voltage V_BUS from a power pin (e.g., A4ofFIG.2) of the USB receptacle110and distribute power supplied by the VBUS voltage V_BUS to other components of the USB device100. In some embodiments, when the USB device100supports a download faced port (DFP), the power circuit140may provide the VBUS voltage V_BUS to a power pin (e.g., A4ofFIG.2) of the USB receptacle110. In some embodiments, the USB device100may support a dual role port (DRP) that is switchable between a source (or a host) and a sink (or a device). In some embodiments, the power circuit140may generate a VCONN voltage for providing power for the active cable and provide the VCONN voltage to the termination circuit120. The VCONN voltage may be provided to a CC1pin (e.g., A5ofFIG.2) or a CC2pin (e.g., B5ofFIG.2) of the USB receptacle110due to an operation of the termination circuit120via the control of the port controller130. As used herein, a voltage for transmitting power, such as the VBUS voltage V_BUS and the VCONN voltage, may be referred to as a power supply voltage. Referring toFIG.2, a USB receptacle110′ may have a structure according to USB Type-C. The USB receptacle110′ may have a symmetrical pin arrangement, such that the USB receptacle110′ may be properly coupled with a USB plug regardless of a direction or orientation, e.g., inserted up or down. The USB receptacle110′ may include a TX1+ pin A2, a TX1− pin A3, an RX1+ pin B11, an RX1− pin B10, a TX2+ pin B2, a TX2− pin B3, an Rx2+ pin A11, and an RX2− pin A10as a data bus. The USB receptacle110′ may include VBUS pins A4, A9, B4, and B9, and the CC1pin A5as a power bus and the CC2pin B5may also transmit a VCONN voltage according to a direction in which the USB receptacle110′ is coupled to the USB plug. Also, the USB receptacle110′ may include two sideband use (SBU) pins A8and B8and two channel configuration (CC) pins A5and B5. The CC1pin A5and the CC2pin B5may be referred to collectively as a CC pin. The USB plug coupled to the USB receptacle110′ may include one CC pin CC unlike the USB receptacle110′, and include a dedicated VCOON pin. Finally, the USB receptacle110′ may include four ground (GND) pins A1, A12, B1, and B12in an outer portion thereof. As described above, when a foreign material is introduced into the USB receptacle110′, an electrical short may occur in a USB cable connected to the USB receptacle110′, or pins included in the USB receptacle110′ may be released, such that an electrical short may occur between at least two pins. In particular, when an electrical path is formed between power pins (e.g., the VBUS pins A4, A9, B4, and B9) and other pins, leakage currents may markedly increase. For example, the pins A3, A5, A8, A10, B3, B5, B8, and B10located adjacent to the VBUS pins A3, A9, B4, and B9may easily have a short circuit with the VBUS pins A3, A9, B4, and B9. In some embodiments, the OVP circuit150may protect the USB device100from an overvoltage occurring at an arbitrary pin other than power pins (e.g., the VBUS pins A4, A9, B4, and B9) and ground pins (e.g., the GND pins A1, A12, B1, and B12)) in the USB receptacle110′. Furthermore, in some embodiments, the OVP circuit150ofFIG.1may protect the USB device100from an overvoltage occurring at the pins A3, A5, A8, A10, B3, B5, B8, and B10that are located adjacent to the VBUS pins A4, A9, B4, and B9. Hereinafter, an operation of protecting the USB100from an overvoltage occurring at the CC1pin A5adjacent to the VBUS pin A4will be mainly described. FIG.3is a block diagram of a USB device300according to an example embodiment. Specifically,FIG.3illustrates the USB device300including an OVP circuit350configured to protect the USB device300from an overvoltage occurring at a CC1pin A5. Similar to the USB device100ofFIG.1, the USB device300may include a USB receptacle310, a termination circuit320, a port controller330, and an OVP circuit350. InFIG.3, the same descriptions as with reference toFIG.1will not be repeated. Referring toFIG.3, the OVP circuit350may include an OVP switch351and a switch controller352. The OVP switch351may be coupled to one or more CC pins described above. While the operation of the OVP circuit350is described below with respect to a CC1pin A5, it is understood that the operation may also be performed with respect to a CC2pin B5(and VBUS pin B4). For example, a CC1pin A5of the USB receptacle310, and may be coupled to the termination circuit320to interrupt VCONN. The OVP switch351may electrically connect the CC1pin A5to the termination circuit320or disconnect the CC1pin A5from the termination circuit320in response to a control signal CTR received from the switch controller352. When the CC1pin A5is electrically connected to the termination circuit320by the OVP switch351, the OVP switch351may have an on-resistance Ron. To minimize the distortion of a signal passing through the CC1pin A5, the OVP switch351may have a low on-resistance Ron. In addition, when the CC1pin A5is electrically connected to the termination circuit320by the OVP switch351, the OVP switch351may not limit a swing of the signal passing through the CC1pin A5. Thus, as described below with reference toFIG.5, the OVP switch351may receive a boosted voltage. The switch controller352may be coupled to the CC1pin A5of the USB receptacle310and may detect an overvoltage occurring at the CC1pin A5based on a voltage (i.e., an input voltage V_IN) of the CC1pin A5. For example, as described above with reference toFIG.2, the CC1pin A5may be located adjacent, e.g., immediately next, to the VBUS pin A4in the USB receptacle310. Thus, when the CC1pin A5has a short circuit with the VBUS pin A4, a VBUS voltage V_BUS may be applied to the CC1pin A5. The switch controller352may detect the overvoltage occurring at the CC1pin A5based on a level of the input voltage V_IN, control the OVP switch351using the control signal CTR, and electrically disconnect the CC1pin A5from the termination circuit320. The switch controller352may receive a mode signal MD from the port controller330, and provide a detection signal DET to the port controller330. As described above with reference toFIG.1, the detection signal DET may indicate whether an overvoltage has occurred at the CC1pin A5, and the mode signal MD may indicate a mode (i.e., a normal mode or a low-power mode) of the USB device300. The switch controller352may generate the control signal CTR based on both the input voltage V_IN and the mode signal MD. An example of an operation of the switch controller352will be described below with reference toFIG.4. FIG.4is a flowchart of a method of protecting an overvoltage in a USB interface according to an example embodiment. For example, the method ofFIG.4may be performed by the OVP circuit350ofFIG.3. Hereinafter,FIG.4will be described with reference toFIG.3. In operation S10, an operation of detecting an overvoltage may be performed. For example, the switch controller352may determine whether the overvoltage occurs based on an input voltage V_IN of a CC1pin A5. In some embodiments, an overvoltage may refer to a voltage that deviates from a voltage range defined by a USB standard for the CC1pin A5. For example, the USB standard may define a voltage level between −0.25 V and 1.8 V for a signal passing through the CC1pin A5, and an overvoltage is considered to have occurred when the CC1pin A5has a voltage that deviates from a range between −0.25 V and 1.8 V. In some embodiments, an overvoltage may be determined based on a maximum input voltage of internal circuits of the USB device300. For example, the internal circuits (e.g., the termination circuit320and the port controller330) of the USB device300may receive a voltage of about 3.3 V as a positive supply voltage (e.g., VDD ofFIG.5), and an overvoltage may be considered to have occurred when a detected voltage deviates from range between 0 V and 3.3 V. In some embodiments, the overvoltage may correspond to a voltage that deviates from a voltage range between 0 V and 5 V. In some embodiments, the overvoltage may be considered to have occurred when a detected voltage deviates from a range including a predetermined margin and one of the above-described voltage ranges. As shown inFIG.4, when the overvoltage is not detected, operation S10may be repeatedly performed, whereas when the overvoltage is detected, operation S30may be subsequently performed. In operation S30, an operation of turning off the OVP switch351may be performed. For example, the switch controller352may generate a control signal CTR so that the OVP switch351may electrically disconnect the CC1pin A5from the termination circuit320, i.e., the OVP switch351may be turned off. In operation S50, an operation of determining whether the overvoltage has been eliminated may be performed. For example, the switch controller352may determine whether the overvoltage has been eliminated at the CC1pin A5based on the input voltage V_IN of the CC1pin A5. As shown inFIG.4, when the overvoltage has not been eliminated, operation S50may be repeatedly performed, and the OVP switch351may remain turned off. Otherwise, when the overvoltage has been eliminated, operation S70may be subsequently performed. In operation S70, an operation of determining a mode of the USB device300may be performed. For example, the switch controller352may determine the mode of the USB device300based on a mode signal MOD received from the port controller330. As shown inFIG.4, when the USB device300is in a normal mode, operation S91may be subsequently performed, whereas when the USB device300is in a low-power mode, operation S93may be subsequently performed. When the USB device300is in the normal mode, an operation of setting an on-resistance Ron of the OVP switch351as a first resistance R1may be performed in operation S91. As described above with reference toFIG.3, the first resistance R1may correspond to a relatively low resistance to reduce the distortion of a signal passing through the CC1pin A5. For example, the switch controller352may generate a control signal CTR having a boosted voltage so that the OVP switch351may have the first resistance R1as the on-resistance Ron. As described below with reference toFIG.5, the switch controller352may include a charge pump (e.g.,51ofFIG.5) configured to generate a boosted voltage from positive supply voltages of internal circuits of the USB device300. As used herein, the first resistance R1may refer to a resistance lower than a second resistance R2to be described below. When the USB device300is in the low-power mode, an operation of setting the on-resistance Ron of the OVP switch351as the second resistance R2may be performed in operation S93. The second resistance R2may be higher than the first resistance R1. For example, the switch controller352may generate a control signal CTR having an unboosted voltage such that the OVP switch351has the second resistance R2as the on-resistance Ron, and the charge pump included in the switch controller352may be powered down. Thus, the switch controller352may consume reduced power in the low-power mode. As a result, efficiency of the USB device300may be improved in the low-power mode. FIG.5is a block diagram of a switch controller50according to an example embodiment. For example,FIG.5illustrates an example of the switch controller352ofFIG.3. As described above with reference toFIG.3, the switch controller50ofFIG.5may receive an input voltage V_IN from the CC1pin A5, receive a mode signal MD from the port controller330, and generate a detection signal DET and a control signal CTR. As shown inFIG.5, the switch controller50may include a charge pump51, an overvoltage detector52, and a control circuit53. Hereinafter,FIG.5will be described with reference toFIGS.3and4. The charge pump51may receive a positive supply voltage VDD and generate a boosted voltage (i.e., an output voltage V_OUT) based on the positive supply voltage VDD. The output voltage V_OUT generated by the charge pump51may be provided by the control circuit53to an OVP switch351under certain conditions, described below. The OVP switch351may provide a first resistance R1as an on-resistance Ron in response to the output voltage V_OUT. In some embodiments, the OVP switch351may include an n-channel field-effect transistor (NFET), and the charge pump51may generate an output voltage V_OUT that is higher than the positive supply voltage VDD. In some embodiments, the OVP switch351may include a p-channel FET (PFET), and the charge pump51may generate an output voltage V_OUT that is lower than a ground voltage. The charge pump51may have an arbitrary, i.e., any, configuration that generates an output voltage V_OUT. For example, the charge pump51may include at least one capacitor and at least one switch and receive a clock signal. The charge pump51may operate or be powered down in response to an enable signal ENA received from the control circuit53. For example, the charge pump51may generate a boosted output voltage V_OUT from the positive supply voltage VDD in response to an activated enable signal ENA and may be powered down in response to a deactivated enable signal ENA. The overvoltage detector52may receive an input voltage V_IN from the CC1pin A5and determine whether an overvoltage has occurred at the CC1pin A5based on the input voltage V_IN. For example, the overvoltage detector52may include resistors Ra and Rb that divide the input voltage V_IN and a comparator CMP. The comparator CMP may compare a voltage divided from the input voltage V_IN with a reference voltage V_REF, and output an activated detection signal DET when the divided voltage is higher than the reference voltage V_REF. Alternatively, the overvoltage detector52may have any structure that generates the detection signal DET according to a magnitude of the input voltage V_IN. The control circuit53may generate an enable signal ENA and a control signal CTR based on the detection signal DET received from the overvoltage detector52and the mode signal MD received from the port controller130. For example, in response to the activated detection signal DET, the control circuit53may output a control signal CTR to turn off the OVP switch351. Also, in response to a mode signal MD indicating a low-power mode, the control circuit53may output a deactivated enable signal ENA to power down the charge pump51. As described below with reference toFIG.6, in some embodiments, the control circuit53may include at least one logic gate to receive the detection signal DET and/or the mode signal MD as input signals, and include at least one switch that is turned on/off based on an output signal of the at least one logic gate. Examples of a configuration and an operation of the control circuit53will be described below with reference toFIGS.6,8, and10. FIG.6is a block diagram of a USB device600according to an example embodiment.FIGS.7A and7Bare diagrams of examples of an operation of the USB device600ofFIG.6, according to example embodiments. Specifically,FIG.6illustrates the USB device600including an OVP switch610including an NFET N60and a switch controller620configured to control the OVP switch610, andFIGS.7A and7Billustrate signals of the USB device600ofFIG.6with respect to time. InFIGS.6,7A, and7B, it is assumed that the signals are active high signals. Thus, an activated signal may have a high level, while a deactivated signal may have a low signal. InFIGS.7A and7B, repeated descriptions will not be repeated. Referring toFIG.6, the OVP switch610may include an NFET N60to serve as a switch that is turned on and off based on a control signal CTR. Although only one NFET N60is illustrated inFIG.6, in some embodiments, the OVP switch610may include a plurality of NFETs connected in series that commonly receive the control signal CTR and/or a plurality of NFETs connected in parallel to each other that commonly receive the control signal CTR. The NFET N60may have an on-resistance Ron, which is reduced as a gate voltage (i.e., a voltage of the control signal CTR) increases. The switch controller620may include a charge pump621and a control circuit623. The control circuit623may include a control logic623_1, a first switch623_2, and a second switch623_3. The control logic623_1may receive a detection signal DET and a mode signal MD, and generate a first switch signal SW1and a second switch signal SW2based on the detection signal DET and the mode signal MD. The first switch623_2may connect a gate of the NFET N60to a ground voltage or the second switch623_3based on the first switch signal SW1. The second switch623_3may connect the first switch623_2to a positive supply voltage VDD or the charge pump621based on the second switch signal SW2. States of the first switch623_2and the second switch623_3shown inFIG.6may correspond to states in which the first switch623_2and the second switch623_3receive a deactivated first switch signal SW1and a deactivated second switch signal SW2, i.e., a low-level first switch signal SW1and a low-level second switch signal SW2, respectively. Referring toFIG.7A, the mode signal MD may have a low level in a normal mode until a time point t72, and have a high level in a low-power mode from the time point t72. Alternatively, the mode signal MD may have a high level in the normal mode and a low level in the low-power mode. Until a time point t70, an overvoltage may not be detected at the CC1pin A5and, thus, the detection signal DET may be at a low level. The control logic623_1may generate a high-level enable signal ENA based on a low-level mode signal MD, so that the charge pump621may generate an output voltage V_OUT. Also, the control logic623_1may generate a low-level first switch signal SW1and a low-level second switch signal SW2based on the low-level detection signal DET. As a result, the first switch623_2and the second switch623_3may be in states shown inFIG.6, and the output voltage V_OUT of the charge pump621may be provided as a control signal CTR to the OVP switch610. Thus, the on-resistance Ron of the OVP switch610may correspond to the first resistance R1lower than the second resistance R2. At the time point t70, the overvoltage may occur at the CC1pin A5and, thus, the detection signal DET may transition to a high level. In response to an activated detection signal DET, the control logic623_1may output an activated first switch signal SW1, so that the control signal CTR may have a ground voltage GND due to the first switch623_2. Thus, the NFET N60may and the OVP switch610may be turned off. At a time point t71, the overvoltage may be eliminated at the CC1pin A5and thus, the detection signal DET may transition to a low level. In response to a deactivated detection signal DET, the control logic623_1may output a deactivated first switch signal SW1, so that the control signal CTR may have an output voltage V_OUT. At the time point t72, the USB device600may be switched from the normal mode to the low-power mode and the mode signal MD may transition to a high level. In response to a high-level mode signal MD, the control logic623_1may output a deactivated enable signal ENA and, thus, the charge pump621may be powered down. Also, in response to the high-level mode signal MD, the control logic623_1may output an activated second switch signal SW2, so that a positive supply voltage VDD may be provided as a control signal CTR to the OVP switch610. Thus, the on-resistance Ron of the OVP switch610may correspond to the second resistance R2higher than the first resistance R1. At a time point t73, an overvoltage may occur at the CC1pin A5and, thus, the detection signal DET may transition to a high level. In response to an activated detection signal DET, the control logic623_1may output an activated first switch signal SW1, so that the control signal CTR may have a ground voltage GND due to the first switch623_2. Thus, the NFET N60and the OVP switch610may be turned off. At a time point t74, the overvoltage may be eliminated at the CC1pin A5and, thus, the detection signal DET may transition to a low level. In response to a deactivated detection signal DET, the control logic623_1may output a deactivated first switch signal SW1, so that the control signal CTR may have a positive supply voltage VDD. Referring toFIG.7B, in some embodiments, the charge pump621may be powered down even in the normal mode when an overvoltage is detected. For example, at a time point t70ofFIG.7B, an overvoltage may occur at the CC1pin A5and, thus, the detection signal DET may transition to a high level. In response to an activated detection signal DET, the control logic623_1may output not only an activated first switch signal SW1but also a deactivated enable signal ENA. As a result, the charge pump621may be powered down. Thus, power consumption may be reduced even in the normal mode when the overvoltage is detected. FIG.8is a block diagram of a USB device800according to an example embodiment.FIG.9is a timing diagram of an example of an operation of the USB device800ofFIG.8, according to an example embodiment. Specifically,FIG.8illustrates the USB device800including an OVP switch810including a PFET P80and a switch controller820configured to control the OVP switch810.FIG.9illustrates signals of the USB device800ofFIG.8with respect to time. InFIGS.8and9, it is assumed that the signals are active high signals, and the same descriptions as with reference toFIGS.6,7A, and7Bwill not be repeated. Referring toFIG.8, the OVP switch810may include a PFET P80that serves as a switch that is turned on and off based on a control signal CTR. AlthoughFIG.8illustrates only one PFET P80, in some embodiments, the OVP switch810may include a plurality of PFETs connected in series to each other to commonly receive a control signal CTR, and/or a plurality of PFETs connected in parallel to each other to commonly receive the control signal CTR. The PFET P80may have an on-resistance Ron, which is reduced as a gate voltage (i.e., a voltage of the control signal CTR) is reduced. The switch controller820may include a charge pump821and a control circuit823. Unlike the charge pump621ofFIG.6that generates the output voltage V_OUT higher than the power supply voltage VDD, the charge pump821may generate an output voltage V_OUT lower than a ground voltage. The control circuit823may include a control logic823_1, a first switch823_2, and a second switch823_3. The first switch823_2may connect a gate of the PFET P80to a positive supply voltage VDD or the second switch823_3based on a first switch signal SW1. The second switch823_3may connect the first switch823_2to the ground voltage or the charge pump821based on a second switch signal SW2. States of the first switch823_2and the second switch823_3shown inFIG.8may correspond to a deactivated first switch signal SW1and a deactivated second switch signal SW2, i.e., a low-level first switch signal SW1and a low-level second switch signal SW2, respectively. Referring toFIG.9, similar toFIGS.7A and7B, a mode signal MD may have a low level in a normal mode until a time point t92, and have a high level in a low-power mode from the time point t92. Also, an overvoltage may occur at a CC1pin A5at a time point t90and a time point t93, while the overvoltage may be eliminated at the CC1pin A5at a time point t91and a time point t94. Until the time point t90, a detection signal DET may be at a low level, and the control logic823_1may generate a low-level first switch signal SW1and a low-level second switch signal SW2based on the low-level detection signal DET. Thus, the first switch823_2and the second switch823_3may be in states shown inFIG.8, and an output voltage V_OUT of the charge pump821may be provided as a control signal CTR to the OVP switch810. Thus, an on-resistance Ron of the OVP switch810may correspond to a first resistance R1lower than a second resistance R2. At the time point t90, the detection signal DET may transition to a high level. The control logic823_1may output an activated first switch signal SW1in response to an activated detection signal DET and thus, the control signal CTR may have a positive supply voltage VDD due to the first switch823_2. Thus, the PFET P80and the OVP switch810may be turned off. Next, at the time point t91, the detection signal DET may transition to a low level, so that the control logic823_1may output a deactivated first switch signal SW1in response to a deactivated detection signal DET. As a result, the control signal CTR may have an output voltage V_OUT. In some embodiments, as described above with reference toFIG.7B, the control logic823_1may output a deactivated enable signal ENA unlike shown inFIG.9, so that the charge pump821may be powered down from the time point t90to the time point t91. At the time point t92, the control logic823_1may output a deactivated enable signal ENA in response to the high-level mode signal MD and, thus, the charge pump821may be powered down. Also, the control logic823_1may output an activated second switch signal SW2in response to the high-level mode signal MD, so that a ground voltage GND may be provided as a control signal CTR to the OVP switch810. As a result, the on-resistance Ron of the OVP switch810may correspond to the second resistance R2higher than the first resistance R1. At the time point t93, the detection signal DET may transition to a high level and the control logic823_1may output an activated first switch signal SW1in response to an activated detection signal DET, so that the control signal CTR may have a positive supply voltage VDD due to the first switch823_2. Thus, the PFET P80may be turned off, and the OVP switch810may be turned off. Next, at a time point t94, the detection signal DET may transition to a low level. In response to a deactivated detection signal DET, the control logic823_1may output a deactivated first switch signal SW1and thus, the control signal CTR may have a ground voltage GND. In some embodiments, the OVP switch351ofFIG.3may include an NFET and a PFET connected in parallel and/or in series to each other. Thus, the switch controller352may include a first charge pump that generates a first output voltage higher than the positive supply voltage VDD and a second charge pump that generates a second output voltage lower than the ground voltage GND. The switch controller352may perform the above-described operations with reference toFIGS.7A,7B, and8. Thus, both the first charge pump and the second charge pump may be powered down in the low-power mode. FIG.10is a block diagram of a USB device900according to an example embodiment.FIGS.11A and11Bare diagrams of examples of an operation of the USB device900ofFIG.10, according to example embodiments. Specifically,FIG.10illustrates the USB device900including an OVP switch910including first and second OVP switches connected in parallel, and a switch controller920to control the OVP switch910.FIGS.11A and11Billustrate signals of the USB device900ofFIG.10with respect to time. InFIGS.10,11A, and11B, it is assumed that the signals are active high signals. Although the OVP switch910including NFETs N91and N92as the first and second OVP switches is illustrated inFIGS.10,11A, and11B, it will be understood that embodiments may be also applied to an OVP switch including PFETs as the first and second OVP switches. Hereinafter, the same descriptions as with reference toFIGS.7A and7Bwill not be repeated. Referring toFIG.10, the OVP switch910may include a first NFET N91and a second NFET N92connected in parallel, and that receive different signals, e.g., a first control signal CTR1and a second control signal CTR2, respectively. The first NFET N91may function as a first OVP switch that is turned on and off based on the first control signal CTR1, while the second NFET N92may function as a second OVP switch that is turned on and off based on the second control signal CTR2. The switch controller920may include a charge pump921and a control circuit923. The control circuit923may include a control logic923_1, a first switch923_2, and a second switch923_3. The control logic923_1may receive a detection signal DET and a mode signal MD, and generate a first switch signal SW1and a second switch signal SW2based on the detection signal DET and the mode signal MD. The first switch923_2may connect a gate of the first NFET N91to a ground voltage or the charge pump921based on the first switch signal SW1. The second switch923_3may connect a gate of the second NFET N92to a positive supply voltage VDD or the ground voltage based on the second switch signal SW2. States of the first switch923_2and the second switch923_3shown inFIG.10correspond to a deactivated first switch signal SW1and a deactivated second switch signal SW2, i.e., a low-level first switch signal SW1and a low-level second switch signal SW2, respectively. Referring toFIG.11A, in some embodiments, the switch controller920may turn off the second OVP switch (i.e., the second NFET N92) in a normal mode, and turn off the first OVP switch (i.e., the first NFET N91) in a low-power mode. Thus, an on-resistance Ron of the OVP switch910may be dependent on the first NFET N91in the normal mode, and be dependent on the second NFET N92in the low-power mode. Since the first NFET N91may receive an output voltage V_OUT from the charge pump921, when an overvoltage does not occur at the CC1pin A5, the OVP switch910may have a first resistance R1as the on-resistance Ron in the normal mode, and have a second resistance R2, which is higher than the first resistance R1, in the low-power mode. As shown inFIG.11A, the mode signal MD may have a low level in the normal mode until a time point t12and a high level in the low-power mode from the time point t12. Alternatively, the mode signal MD may have a high level in the normal mode and a low level in the low-power mode. Until a time point t10, an overvoltage may not be detected at the CC1pin A5and thus, the detection signal DET may be at a low level. The control logic923_1may generate a high-level enable signal ENA based on the low-level mode signal MD, so that the charge pump921may generate an output voltage V_OUT. Also, the control logic923_1may generate a low-level first switch signal SW1and a low-level second switch signal SW2based on the low-level detection signal DET. Thus, the first switch923_2and the second switch923_3are in states shown inFIG.10, the output voltage V_OUT of the charge pump921may be provided as a first control signal CTR1to the first NFET N91, and a ground voltage GND may be provided as a second control signal CTR2to the second NFET N92. Thus, the first NFET N91may be turned on, while the second NFET N92may be turned off. Due to the output voltage V_OUT higher than a positive supply voltage VDD, the first NFET N91may provide the first resistance R1lower than the second resistance R2. At the time point t10, an overvoltage may occur at the CC1pin A5and, thus, the detection signal DET may transition to a high level. In response to an activated detection signal DET, the control logic923_1may output an activated first switch signal SW1, so that the first control signal CTR1may have a ground voltage GND due to the first switch923_2. Thus, the first NFET N91may be turned off, and the OVP switch910may be turned off. At a time point t11, the overvoltage may be eliminated at the CC1pin A5and, thus, the detection signal DET may transition to a low level. In response to a deactivated detection signal DET, the control logic923_1may output a deactivated first switch signal SW1, so that the first control signal CTR1may have an output voltage V_OUT. In some embodiments, as described above with reference toFIG.7B, the control logic923_1may output a deactivated enable signal ENA unlike shown inFIG.11Aso that the charge pump921may be powered down from the time point t10to the time point t11. At a time point t12, the USB device900may be switched from the normal mode to the low-power mode and the mode signal MD may transition to a high level. In response to the high-level mode signal MD, the control logic923_1may output a deactivated enable signal ENA and, thus, the charge pump921may be powered down. Also, in response to the high-level mode signal MD, the control logic923_1may output an activated first switch signal SW1, so that the ground voltage GND may be provided as the first control signal CTR1to the first NFET N91. In addition, in response to the high-level mode signal MD, the control logic923_1may output an activated second switch signal SW2, so that the positive supply voltage VDD may be provided as the second control signal CTR2to the second NFET N92. As a result, the first NFET N91may be turned off, and the second NFET N92may be turned on. Thus, an on-resistance Ron of the OVP switch910may correspond to the second resistance R2higher than the first resistance R1. At a time point t13, an overvoltage may occur at the CC1pin A5and, thus, the detection signal DET may transition to a high level. In response to an activated detection signal DET, the control logic923_1may output a deactivated second switch signal SW2, so that the second control signal CTR2may have a ground voltage GND due to the second switch923_3. Thus, the second NFET N92may be turned off, and the OVP switch910may be turned off. At a time point t14, the overvoltage may be eliminated at the CC1pin A5and, thus, the detection signal DET may transition to a low level. In response to a deactivated detection signal DET, the control logic923_1may output an activated second switch signal SW2, so that the second control signal CTR2may have a positive supply voltage VDD. Referring toFIG.11B, in some embodiments, the switch controller920may turn off the first NFET N91in a low-power mode, and simultaneously turn on or off the first NFET N91and the second NFET N92in the normal mode. Thus, the on-resistance Ron of the OVP switch910may be dependent on the first NFET N91and the second NFET N92, which are connected in parallel, in the normal mode, and dependent only on the second NFET N92in the low-power mode. The first NFET N91may receive an output voltage V_OUT from the charge pump921. Since the first NFET N91and the second NFET N92are turned on together, when an overvoltage does not occur at the CC1pin A5, the OVP switch910may have the first resistance R1as the on-resistance Ron in the normal mode and the second resistance R2, higher than the first resistance R1, in the low-power mode. As shown inFIG.11B, until the time point t10, the control logic923_1may output an deactivated first switch signal SW1and output an activated second switch signal SW2in response to a deactivated detection signal DET. Thus, the first control signal CTR1and the second control signal CTR2may have an output voltage V_OUT and a positive supply voltage VDD, respectively, and both the first NFET N91and the second NFET N92may be turned on. FIG.12is a flowchart of a method of protecting an overvoltage in a USB interface according to an example embodiment. Specifically,FIG.12illustrates examples of operation S91and operation S93ofFIG.4. For example, the method ofFIG.12may be performed by the switch controller50ofFIG.5. Hereinafter, the flowchart ofFIG.12will be described with reference toFIGS.4and5. Subsequently to operation S50ofFIG.4, in operation S70′, the switch controller50may determine a mode of a USB device (e.g.,300ofFIG.3) based on a mode signal MD. When the mode signal MD corresponds to a normal mode, operation S91′ may be subsequently performed. When the mode signal MD corresponds to a low-power mode, operation S93′ may be subsequently performed. When the mode signal MD corresponds to the normal mode, in operation S91′, an operation of setting an on-resistance Ron of an OVP switch (e.g.,351ofFIG.3) as a first resistance R1may be performed. As shown inFIG.12, operation S91′ may include operation S91_1. In operation S91_1, an operation of providing an output voltage V_OUT of the charge pump51to the OVP switch may be performed. The output voltage V_OUT may be a voltage boosted by the charge pump51. Thus, the OVP switch may have a relatively low on-resistance Ron, i.e., the first resistance R1. Subsequently to operation S91′, operation S10ofFIG.4may be performed. When the mode signal MD corresponds to the low-power mode, in operation S93′, an operation of setting the on-resistance Ron of the OVP switch (e.g.,351ofFIG.3) as a second resistance R2may be performed. As shown inFIG.12, operation S93′ may include operation S93_1. In operation S93_1, an operation of powering the charge pump51down may be performed. As a result, power consumption may be reduced and efficiency of the low-power mode may be improved. Subsequently to operation S93′, operation S10ofFIG.4may be performed. By way of summation and review, one or more embodiments may provide a circuit and method of protecting an overvoltage. One or more embodiments may provide a circuit and method of reducing power consumption. One or more embodiments may provide a circuit and method of providing different on-resistances in accordance with a mode and/or overcharge detection. Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims. | 44,787 |
11862965 | DETAILED DESCRIPTION Exemplary embodiments are described in detail herein, and examples thereof are represented in the accompanying drawings. When the following descriptions relate to the accompanying drawings, unless otherwise stated, same digitals in different accompanying drawings represent same or similar essential factors. Implementations described in the following exemplary embodiments do not represent all implementations consistent with the present disclosure. On the contrary, the implementations are merely examples of apparatuses and methods that are described in detail in the appended claims and consistent with some aspects of the present disclosure. Those skilled in the art may easily figure out other implementations of the present disclosure after considering the specification and practicing the application disclosed herein. The present disclosure is intended to cover any variations, purposes or applicable changes of the present disclosure. Such variations, purposes or applicable changes follow the general principle of the present disclosure and include common knowledge or conventional technical means in the technical field which is not disclosed in the present disclosure. This specification and embodiments are merely considered as illustrative, and the real scope and spirit of the present disclosure are defined by the appended claims. A latch-up effect means that a parasitic thyristor structure (Silicon Controlled Rectifier, SCR) in a CMOS circuit is triggered and turned on, creating a low resistance path between a power supply (power VDD/VPP) and a ground wire (GND/VSS), and causing the circuit to fail to work properly and even burning a chip. Referring toFIG.1andFIG.2,FIG.1is a schematic cross-sectional view of a semiconductor structure, andFIG.2is an equivalent circuit diagram of a parasitic transistor in the semiconductor structure. InFIG.1, a source-drain region of an NMOS, a P substrate, and an N-well constitute a parasite NPN transistor, and a source-drain region of a PMOS, an N-well, and a P substrate constitute a parasite PNP transistor. For the parasite NPN transistor, the source-drain region of the NMOS constitutes an emission region thereof, the P substrate constitutes a base region thereof, and the N-well constitutes a collector region thereof. For the parasite PNP transistor, the source-drain region of the PMOS constitutes an emission region thereof, the N-well constitutes a base region thereof, and the P substrate constitutes a collector region thereof. In addition, there is a well resistor Rwell between the N-well and the power supply VDD, and there is a substrate resistor Rsub between the P substrate and the ground wire GND. Under normal circumstances, the parasite NPN transistor and the parasite PNP transistor are cut off, and no latch-up effect is caused. However, as shown inFIG.1andFIG.2, when subjected to external interference, a voltage drop of the well resistor Rwell is greater than a turn-on voltage of the parasite PNP transistor, and the parasite PNP transistor is turned on, such that a current flows through the substrate a resistor Rsub, a voltage drop of the substrate resistor Rsub is greater than a turn-on voltage of the parasite NPN transistor, and the parasite NPN transistor is turned on. In this way, a large current flows through the well resistor Rwell, and the voltage drop of the well resistor Rwell is increased, such that the parasite PNP transistor is further turned on, thus forming a positive feedback amplification loop, to amplify the current continuously. Consequently, an extremely large turn-on current is formed between the power supply and the ground wire, burning the chip. The external interference may be, for example, as shown inFIG.3, a case that when the chip starts to work, a parasitic capacitor between the N-well and the P substrate generates enough current due to a change in the power supply VDD, causing a latch-up effect. Further, alternatively, referring toFIG.4, noise coupling under environmental or system interference causes the power supply VDD to overshoot, resulting in triggering of a parasitic transistor. Further, alternatively, referring toFIG.5, during a latch-up test, a relatively large voltage is applied to an ESD protection circuit, causing a small amount of charged carriers in a protection circuit to enter a substrate, resulting in triggering of a parasitic transistor. FIG.6is a circuit diagram of an ESD protection circuit according to an embodiment of the present disclosure.FIG.7is a semiconductor structure diagram of the ESD protection circuit according to the embodiment shown inFIG.6. As shown inFIG.6andFIG.7, a chip includes a first pad VPP and a second pad VSS, and the ESD protection circuit includes a trigger unit101and a discharge transistor M1. The trigger unit101is provided with a trigger terminal NO. The trigger terminal NO of the trigger unit101is connected to a control terminal NO of the discharge transistor M1. The trigger unit101is located between the first pad VPP and the second pad VSS. The discharge transistor M1is further provided with a first terminal, a second terminal, and a substrate terminal. The first terminal of the discharge transistor M1is connected to the first pad VPP, the second terminal of the discharge transistor M1is connected to the second pad VSS, and the substrate terminal of the discharge transistor M1is also connected to the trigger terminal NO. The trigger unit101generates a trigger signal when detecting an electrostatic pulse. The discharge transistor M1is turned on under the trigger of the trigger signal, to discharge an electrostatic charge from the first pad VPP to the second pad VSS. Referring toFIG.7, when the discharge transistor M1is an N-type transistor, the discharge transistor M1also includes a parasite NPN transistor and a parasite PN diode. A base of the parasite NPN transistor is the substrate terminal of the discharge transistor M1. A collector of the parasite NPN transistor is a drain of the discharge transistor M1. An emitter of the parasite NPN transistor is a source of the discharge transistor M1. An anode of the parasite PN diode is the substrate terminal of the discharge transistor M1. A cathode of the parasite PN diode is the source of the discharge transistor M1. For example, during a latching test, a relatively large voltage, for example, a voltage of 1.5 times VPP, is applied to the first pad VPP, such that a drain region undergoes ionization (impact ionization), and a resulting hole enters the substrate and flows into the second pad VSS through the resistor R, thereby raising a potential of the substrate. When the potential of the substrate is high enough to cause the parasite PN diode formed by the substrate and the source to be turned on forward (PN diode forward turn on), a voltage at a base of the parasite NPN transistor is also raised, such that the parasite NPN transistor is turned on, thereby forming a low resistance path between the first pad VPP and the second pad VSS. In addition, because a gate of the discharge transistor M1and the substrate are connected (short), a potential of the gate increases with the increase of the potential of the substrate, which in turn causes the parasite NPN transistor to be turned on. When a holding voltage of the discharge transistor M1is less than VPP, the discharge transistor M1enters a latch-up state, causing an electric leakage. An embodiment of the present disclosure provides an ESD protection circuit, referring toFIG.8toFIG.15, with a chip including a first pad VPP and a second pad VSS. The ESD protection circuit includes a trigger unit101and a discharge transistor M1. The trigger unit101is connected between the first pad VPP and the second pad VSS. The first pad VPP is connected to a first voltage. The second pad VSS is connected to a second voltage. The first voltage is greater than the second voltage, that is, a voltage of the first pad VPP is higher than a voltage of the second pad VSS. The first pad VPP may be connected to an input unit to obtain the first voltage through the input unit. The trigger unit101is provided with a trigger terminal NO. A control terminal NO of the discharge transistor M1is connected to the trigger terminal NO of the trigger unit101. A first terminal of the discharge transistor M1is connected to the first pad VPP. A second terminal of the discharge transistor M1is connected to the second pad VSS. The trigger unit101generates a trigger signal when detecting an electrostatic pulse on the first pad VPP. The discharge transistor M1is turned on under the trigger of the trigger signal, to discharge an electrostatic charge to the second pad VSS, and a voltage at a substrate terminal of the discharge transistor M1is pulled to the first voltage or the second voltage, making it difficult for a parasite NPN transistor in the discharge transistor M1to be turned on, thereby effectively reducing the risk of causing a latch-up effect.FIG.8is a circuit diagram of an ESD protection circuit according to an embodiment of the present disclosure. As shown inFIG.8, the ESD protection circuit provided in this embodiment of the present disclosure includes a trigger unit101and a discharge transistor M1, and the discharge transistor M1is an N-type transistor. The trigger unit101is provided with a trigger terminal NO. The discharge transistor M1is provided with a control terminal NO, a first terminal, a second terminal, and a substrate terminal. The control terminal NO of the discharge transistor M1is connected to the trigger terminal NO of the trigger unit101. The first terminal of the discharge transistor M1is connected to a first pad VPP. The second terminal of the discharge transistor M1is connected to a second pad VSS. The substrate terminal of the discharge transistor M1is connected to the second pad VSS. When there is an electrostatic pulse on the first pad VPP, a voltage at the trigger terminal NO of the trigger unit101is raised, and because the control terminal NO of the discharge transistor M1is connected to the trigger terminal NO of the trigger unit101, a voltage at the control terminal NO of the discharge transistor M1is raised. In this way, the discharge transistor M1is turned on, and discharges an electrostatic charge to the second pad VSS. In addition, because there is an electrostatic pulse on the first pad VPP, an increase in a potential of a substrate easily causes a latch-up effect. The substrate terminal of the discharge transistor M1is connected to the second pad VSS, and therefore, a voltage at the substrate terminal is pulled down to a second voltage. The voltage at the substrate terminal is reduced to reduce a voltage at a base of a parasite NPN transistor, making it difficult for the parasite NPN transistor to be turned on, thereby effectively reducing the risk of causing a latch-up effect. In some embodiments, as shown inFIG.9, the trigger unit101includes a trigger capacitor C and a trigger resistor R. The trigger capacitor C and the trigger resistor R are each provided with a first terminal and a second terminal. The first terminal of the trigger capacitor C is connected to the first pad VPP. The first terminal of the trigger resistor R is connected to the second terminal of the trigger capacitor C to form the trigger terminal NO of the trigger unit101. The second terminal of the trigger resistor R is connected to the second pad VSS. When there is an electrostatic pulse on the first pad VPP, impedance of the trigger capacitor C becomes smaller, a voltage at the trigger terminal NO of the trigger unit101is coupled to a voltage on the first pad VPP, a voltage at the control terminal NO of the discharge transistor M1is also raised, and the discharge transistor M1is turned on to discharge an electrostatic charge to the second pad VSS. FIG.10is a circuit diagram of an ESD protection circuit according to an embodiment of the present disclosure. As shown inFIG.10, the ESD protection circuit provided in this embodiment of the present disclosure includes a trigger unit101and a discharge transistor M1, and the discharge transistor M1is a P-type transistor. A control terminal NO of the discharge transistor M1is connected to a trigger terminal NO of the trigger unit101. A first terminal of the discharge transistor M1is connected to a first pad VPP. A second terminal of the discharge transistor M1is connected to a second pad VSS. A substrate terminal of the discharge transistor M1is connected to the first pad VPP, such that a voltage at the substrate terminal is pulled to a first voltage. When there is an electrostatic pulse on the first pad VPP, a voltage at the trigger terminal NO of the trigger unit101is pulled down. Because the control terminal NO of the discharge transistor M1is connected to the trigger terminal NO of the trigger unit101, a voltage at the control terminal NO of the discharge transistor M1is pulled down, such that the discharge transistor M1is turned on and discharges an electrostatic pulse to the second pad VSS. In addition, because the substrate terminal of the discharge transistor M1is connected to the first pad VPP, the voltage at the substrate terminal is raised to the first voltage. The voltage at the substrate terminal is increased to increase a voltage of a base of a parasite PNP transistor, making it difficult for the parasite PNP transistor to be turned on, thereby effectively reducing the risk of causing a latch-up effect. In some embodiments, as shown inFIG.11, the trigger unit101includes a trigger resistor R and a trigger capacitor C. The trigger resistor R and the trigger capacitor C are each provided with a first terminal and a second terminal. The first terminal of the trigger resistor R is connected to the first pad VPP. The first terminal of the trigger capacitor C is connected to the second terminal of the trigger resistor R to form the trigger terminal NO of the trigger unit101. The second terminal of the trigger capacitor C is connected to the second pad VSS. When there is an electrostatic pulse on the first pad VPP, impedance of the trigger capacitor C becomes smaller, the trigger terminal NO of the trigger unit101is coupled to a voltage on the second pad VSS, a voltage at the trigger terminal NO of the discharge transistor M1is pulled down, and the discharge transistor M1is turned on to discharge an electrostatic charge to the second pad VSS. FIG.12andFIG.14are each a circuit diagram of an ESD protection circuit according to an embodiment of the present disclosure. As shown inFIG.12andFIG.14, the ESD protection circuit provided in this embodiment of the present disclosure includes a trigger unit101, a discharge transistor M1, and a control unit102. The control unit102is provided with a control terminal N1. The control terminal N1of the control unit102is connected to a trigger terminal NO of the trigger unit101. The trigger terminal NO of the trigger unit101is connected to a control terminal NO of the discharge transistor M1. A substrate terminal of the discharge transistor M1is connected to the control terminal NO of the discharge transistor M1. When there is an electrostatic pulse on a first pad VPP, impedance of the trigger capacitor C becomes smaller. Because the trigger terminal NO of the trigger unit101is coupled to a voltage on a second pad VSS, a voltage at the trigger terminal NO of the trigger unit101is raised, and a voltage at the control terminal NO of the discharge transistor M1is raised. In this way, the discharge transistor M1is turned on to discharge an electrostatic charge to the second pad VSS. The control terminal N1of the control unit102is connected to the control terminal NO of the discharge transistor M1. When the discharge transistor M1discharges an electrostatic charge on the first pad VPP to the second pad VSS, the control unit102pulls a voltage at the substrate terminal of the discharge transistor M1to a first voltage or a second voltage, such that the voltage at the control terminal of the discharge transistor M1is lower than a turn-on voltage of the discharge transistor M1. In this way, the discharge transistor M1is turned off quickly, preventing a parasitic transistor in the discharge transistor M1from being turned on, thereby reducing the risk of causing a latch-up effect. In some embodiments, as shown inFIG.13andFIG.15, the control unit102includes a protection transistor M2. A first terminal of the protection transistor M2is connected to the first pad VPP or the second pad VSS. A second terminal of the protection transistor M2is used as the control terminal of the control unit102. When there is an electrostatic pulse on the first pad VPP, impedance of the trigger capacitor C becomes smaller. Because the trigger terminal NO of the trigger unit101is coupled to a voltage on the second pad VSS, a voltage at the trigger terminal NO of the trigger unit101is raised, a voltage at the control terminal NO of the discharge transistor M1is raised, and the discharge transistor M1is turned on to discharge an electrostatic charge to the second pad VSS. Subsequently, the protection transistor M2is controlled to be turned on, and a voltage at the second terminal of the protection transistor M2is pulled to the first voltage or the second voltage, such that the voltage at the control terminal of the discharge transistor M1is pulled to the first voltage or the second voltage, that is, the voltage at the substrate terminal of the discharge transistor M1is pulled to the first voltage or the second voltage. In this way, the voltage at the substrate terminal of the discharge transistor M1is lower than the turn-on voltage of the discharge transistor M1, and therefore, the discharge transistor M1cannot be turned on, thereby reducing the risk of causing a latch-up effect. As shown inFIG.13andFIG.15, the control unit102may further include an inverter103. An input terminal of the inverter103is used as the control terminal of the control unit102and is connected to the second terminal of the protection transistor M2. An output terminal of the inverter103is connected to a control terminal of the protection transistor M2. When there is an electrostatic pulse on the first pad VPP, a voltage at the control terminal NO of the discharge transistor M1is raised, and the discharge transistor M1is turned on to discharge an electrostatic charge to the second pad VSS. Subsequently, the electrostatic pulse on the first pad VPP stops, the inverter103controls the protection transistor M2to be turned on, and the voltage at the second terminal of the protection transistor M2is pulled to the first voltage or the second voltage, such that the voltage at the control terminal of the discharge transistor M1is pulled to the first voltage or the second voltage. Therefore, the voltage at the substrate terminal of the discharge transistor M1is pulled to the first voltage or the second voltage, thereby preventing the discharge transistor M1from being turned on. As shown inFIG.13, an ESD protection circuit provided in an embodiment of the present disclosure includes a trigger unit101, a discharge transistor M1, and a control unit102. The control unit102includes a protection transistor M2and an inverter103. The discharge transistor M1and the protection transistor M2are N-type transistors. A first terminal of the protection transistor M2is connected to a second pad VSS. A second terminal of the protection transistor M2is connected to a trigger terminal NO of the trigger unit101. A control terminal of the protection transistor M2is connected to an output terminal of the inverter103. The trigger terminal NO of the trigger unit101is further connected to a control terminal of the discharge transistor M1. The control terminal of the discharge transistor M1is further connected to a substrate terminal of the discharge transistor M1. A first terminal of the discharge transistor M1is connected to a first pad VPP. A second terminal of the discharge transistor M1is connected to the second pad VSS. When there is an electrostatic pulse on the first pad VPP, a voltage at the trigger terminal NO of the trigger unit101is coupled to a voltage on the first pad VPP, a voltage at the trigger terminal NO of the discharge transistor M1is raised, and the discharge transistor M1is turned on. When the discharge transistor M1discharges the electrostatic pulse on the first pad VPP to the second pad VSS, the inverter103controls the protection transistor M2to be turned on, a voltage at the second terminal of the protection transistor M2is coupled to a voltage on the second pad VSS, and the voltage at the second terminal of the protection transistor M2is pulled down. In this case, the voltage at the control terminal of the discharge transistor M1is pulled down, such that a voltage at the substrate terminal of the discharge transistor M1is pulled down, preventing a parasite NPN transistor in the discharge transistor M1from being turned on, thereby reducing the risk of causing a latch-up effect. In some embodiments, as shown inFIG.13, the inverter103includes a first transistor M3and a second transistor M4. A control terminal of the first transistor M3and a control terminal of the second transistor M4are connected to the trigger terminal NO of the trigger unit101to form an input terminal of the inverter. A first terminal of the first transistor M3is connected to the first pad VPP. A second terminal of the first transistor M3is connected to a first terminal of the second transistor M4to form the output terminal of the inverter103. A second terminal of the second transistor M4is connected to the second pad VSS. The first transistor M3is a P-type transistor. The second transistor M4is an N-type transistor. When there is an electrostatic pulse on the first pad VPP, the voltage at the trigger terminal NO of the trigger unit101is coupled to the voltage on the first pad VPP, the voltage at the trigger terminal NO of the discharge transistor M1is raised, and the discharge transistor M1is turned on. The input terminal of the inverter103is connected to the trigger terminal NO of the trigger unit101. When a voltage at the input terminal of the inverter103is raised, the second transistor M4is turned on, and a voltage at the output terminal of the inverter103is coupled to the voltage on the second pad VSS, that is, the voltage at the control terminal of the protection transistor M2is pulled down. When the voltage at the control terminal of the protection transistor M2is lower than a turn-on voltage of the protection transistor M2, the protection transistor M2is turned off, such that the electrostatic pulse on the first pad VPP is discharged to the second pad VSS through the discharge transistor M1. When the electrostatic pulse on the first pad VPP stops, the voltage at the trigger terminal NO of the trigger unit101is pulled down, the voltage at the input terminal of the inverter103is pulled down, the first transistor M3is turned on, and the voltage at the output terminal of the inverter103is coupled to the voltage on the first pad VPP, that is, the voltage at the control terminal of the protection transistor M2is raised. When the voltage at the control terminal of the protection transistor M2is higher than the turn-on voltage of the protection transistor M2, the protection transistor M2is turned on, the voltage at the second terminal of the protection transistor M2is coupled to the voltage on the second pad VSS, and the voltage at the trigger terminal NO of the discharge transistor M1is pulled down, that is, the voltage at the substrate terminal of the discharge transistor M1is pulled down, preventing the parasite NPN transistor in the discharge transistor M1from being turned on, thereby reducing the risk of causing a latch-up effect. As shown inFIG.15, an ESD protection circuit provided in an embodiment of the present disclosure includes a trigger unit101, a discharge transistor M1, and a control unit102. The control unit102includes a protection transistor M2and an inverter103. The discharge transistor M1and the protection transistor M2are P-type transistors. A first terminal of the protection transistor M2is connected to a first pad VPP. A second terminal of the protection transistor M2is connected to a trigger terminal NO of the trigger unit101. A control terminal of the protection transistor M2is connected to an output terminal of the inverter103. The trigger terminal NO of the trigger unit101is further connected to a control terminal of the discharge transistor M1. The control terminal of the discharge transistor M1is further connected to a substrate terminal of the discharge transistor M1. A first terminal of the discharge transistor M1is connected to the first pad VPP. A second terminal of the discharge transistor M1is connected to a second pad VSS. When there is an electrostatic pulse on the first pad VPP, a voltage at the trigger terminal NO of the trigger unit101is coupled to a voltage on the second pad VSS, a voltage at the trigger terminal NO of the discharge transistor M1is pulled down, and the discharge transistor M1is turned on. When the discharge transistor M1discharges the electrostatic pulse on the first pad VPP to the second pad VSS, the inverter103controls the protection transistor M2to be turned on, a voltage at the second terminal of the protection transistor M2is coupled to a voltage on the first pad VPP, and the voltage at the second terminal of the protection transistor M2is raised. In this case, the voltage at the control terminal of the discharge transistor M1is raised, such that a voltage at the substrate terminal of the discharge transistor M1is raised, preventing a parasite PNP transistor in the discharge transistor M1from being turned on, thereby reducing the risk of causing a latch-up effect. When there is an electrostatic pulse on the first pad VPP, a voltage at the trigger terminal NO of the trigger unit101is coupled to a voltage on the second pad VSS, a voltage at the trigger terminal NO of the discharge transistor M1is pulled down, and the discharge transistor M1is turned on. An input terminal of the inverter103is connected to the trigger terminal NO of the trigger unit101. When a voltage at the input terminal of the inverter103is pulled down, a first transistor M3is turned on, a voltage at the output terminal of the inverter103is coupled to the voltage on the first pad VPP, that is, a voltage at the control terminal of the protection transistor M2is raised, and the protection transistor M2is turned off, such that the electrostatic pulse on the first pad VPP is discharged to the second pad VSS through the discharge transistor M1. When the electrostatic pulse on the first pad VPP stops, the voltage at the trigger terminal NO of the trigger unit101is raised, the voltage at the input terminal of the inverter103is raised, a second transistor M4is turned, and the voltage at the output terminal of the inverter103is coupled to the voltage on the second pad VSS, that is, the voltage at the control terminal of the protection transistor M2is pulled down, and the protection transistor M2is turned on. In this case, the voltage at the second terminal of the protection transistor M2is coupled to the voltage on the first pad VPP, and the voltage at the trigger terminal NO of the discharge transistor M1is raised, that is, the voltage at the substrate terminal of the discharge transistor M1is raised, preventing the parasite PNP transistor in the discharge transistor M1from being turned on, thereby reducing the risk of causing a latch-up effect. An embodiment of the present disclosure further provides an ESD protection circuit. Referring toFIG.16, the ESD protection circuit includes a trigger unit101and a discharge transistor M1. The trigger unit101includes a trigger capacitor C and a trigger resistor RO. A first terminal of the trigger capacitor C is connected to a first pad VPP. A second terminal of the trigger capacitor is connected to a first terminal of the trigger resistor RO to form a trigger terminal NO of the trigger unit101. The trigger terminal NO of the trigger unit101is connected to a control terminal of the discharge transistor M1. The control terminal of the discharge transistor M1is connected to a substrate terminal of the discharge transistor M1. A first terminal of the discharge transistor M1is connected to the first pad VPP. A second terminal of the discharge transistor M1is connected to a second pad VSS. A resistance value of the trigger resistor RO is lower than that of the trigger resistor R in the foregoing other embodiments. For example, RO=1/3R. When the resistance value of the trigger resistor RO decreases, a voltage at the control terminal NO of the discharge transistor M1decreases, such that a voltage at the substrate terminal of the discharge transistor M1decreases, preventing a parasite NPN transistor in the discharge transistor M1from being turned on, thereby reducing the risk of causing a latch-up effect. In the foregoing technical solution, the ESD protection circuit includes a trigger unit and a discharge transistor. The trigger unit is connected between a first pad and a second pad, provided with a trigger terminal, and configured to generate a trigger signal when there is an electrostatic pulse on the first pad. The first pad is connected to a first voltage. The second pad is connected to a second voltage. The first voltage is greater than the second voltage. The discharge transistor has a first terminal connected to the first pad, and a second terminal connected to the second pad, and discharges an electrostatic charge to the second pad when triggered by the trigger signal. When there is an electrostatic pulse on the first pad, a voltage at a substrate terminal of the discharge transistor is also raised. Therefore, the voltage at the substrate terminal of the discharge transistor is pulled to the first voltage or the second voltage, to prevent a parasitic transistor at the substrate terminal of the discharge transistor from being turned on, such that the risk of causing a latch-up effect in the ESD protection circuit is reduced and reliability is higher. | 30,304 |
11862966 | To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially used in other embodiments without specific recitation. DESCRIPTION OF EXAMPLE EMBODIMENTS This disclosure describes a surge protector that uses one or more transistors to protect electrical equipment from electrical surges (e.g., surges caused by lightning strikes). The surge protector includes a capacitor that charges using an input power to the surge protector. When the capacitor is charged to a charge threshold, a switch in the surge protector turns on, which causes the surge protector to output the input power. When a surge occurs, a control transistor in the surge protector turns on, which causes the capacitor to discharge. When the capacitor discharges to below the charge threshold, the switch turns off, which causes the surge protector to stop outputting the input power. As a result, the surge protector prevents the surge from reaching downstream electrical equipment, in certain embodiments. FIG.1illustrates an example system100. As seen inFIG.1, the system100includes a surge protector102and one or more devices104connected to the surge protector102. The surge protector102and the devices104may include electrical equipment that is installed outdoors. As a result, the electrical equipment may be exposed to lightning strikes that cause electrical surges that damage the equipment. The surge protector102protects the electrical equipment from these electrical surges. Specifically, the surge protector102uses one or more transistors that switch on or off to prevent the electrical surge from reaching downstream devices104. Additionally, the surge protector102provides other forms of electrical protection. For example, the surge protector102may provide a polarity guard function and an inrush current limiting function. The surge protector102receives electrical power (e.g., a DC input power) and outputs the electrical power to the connected devices104to power those devices104. The surge protector102includes protection circuitry106that cuts off the electrical power to the connected devices104when an electrical surge occurs over the input, which prevents the electrical surge from reaching the devices104. Specifically, and as shown in subsequent figures, the protection circuitry106includes one or more transistors that operate to cut off the electrical power when the electrical surge occurs. FIG.2Aillustrates an example surge protector102in the system100ofFIG.1. As seen inFIG.2A, the surge protector102includes a front end circuit202and protection circuitry106. The protection circuitry106includes a capacitor204, a switch205, a control transistor210, a resistor212, a Zener diode214, a Zener diode216, a resistor218, a resistor220, a Zener diode222, and a resistor224. In particular embodiments, the protection circuitry106electrically protects downstream devices104. The front end circuit202receives and provides an electrical input power (e.g., a DC input power) to the protection circuitry106. The front end circuit202may include one or more preliminary electrical protection components. For example, the front end circuit202may include an electrical fuse that provides some overcurrent protection. As another example, the front end circuit202may include an electromagnetic compatibility (EMC) filter that protects against electromagnetic disturbance. As yet another example, the front end circuit202may include a surge suppressor that provides some protection against voltage spikes. In some embodiments, the front end circuit202does not offer enough electrical protection for the downstream devices104. For example, the front end circuit202may not offer enough protection against electrical surges caused by lightning strikes. The protection circuitry106provides additional electrical protection to the downstream devices104. The resistor212and the capacitor204are connected to the front end circuit202such that the capacitor204charges through the resistor212when the front end circuit202provides the electrical input power (e.g., the DC input power). The resistance of the resistor212and the capacitance of the capacitor204affect how quickly the capacitor204charges (e.g., 10 milliseconds). Additionally, the Zener diode214is connected to the resistor212in parallel with the capacitor204and limits the voltage to which the capacitor204will charge. As a result, the Zener diode214sets a charge threshold (e.g., 15 volts) beyond which the capacitor204does not charge. The switch205turns on when the capacitor204is charged. Specifically, the switch205includes power switch transistors206and208connected in series with one another. The power switch transistors206and208control an output of the surge protector102. As seen inFIG.2A, the sources of the power switch transistors206and208are connected together. Additionally, the drain of the power switch transistor206is connected to the front end circuit202and the drain of the power switch transistor208is connected to the output of the surge protector102. The gates of the power switch transistors206and208are connected to the resistor212and the capacitor204. As a result, as the capacitor204charges, the power switch transistors206and208gradually turn on. When the capacitor204has not charged to the charge threshold set by the Zener diode214, the power switch transistors206and208are off and do not conduct the electrical input power from the front end circuit202to the output of the surge protector102. When the capacitor204has charged to the charge threshold, the power switch transistors206and208are turned on and conduct the electrical input power from the front end circuit202to the output of the surge protector102. Furthermore, the sources of the power switch transistors206and208are connected together and the gates of the power switch transistors206and208are connected together. As a result, the power switch transistors206and208may turn on and off at the same time. When a voltage surge occurs (e.g., from a lightning strike) the voltage of the electrical input power spikes. The front end circuit202may not be sufficient to prevent the voltage spike from travelling to downstream components. The protection circuitry106prevents the voltage spike from reaching downstream devices104connected to the surge protector102. When the voltage of the electrical input power spikes, the Zener diode216turns on. Stated differently, the Zener diode216sets a voltage threshold, and when the voltage of the electrical input power exceeds the voltage threshold, the Zener diode216begins conducting through the resistor218. As seen inFIG.2A, the gate of the control transistor210is connected to the resistor218. As a result, when the Zener diode216begins to conduct, the control transistor210turns on and begins to discharge the capacitor204through the resistor224that is connected to the drain of the control transistor210. The resistance of the resistor224and the capacitance of the capacitor204affect how quickly the capacitor204discharges. Discharging the capacitor204reduces the voltage across the capacitor204below the charge threshold set by the Zener diode214, which turns off the power switch transistors206and208so that the switch205stops conducting the electrical input power to the output of the surge protector102. The power switch transistors206and208may be selected based on their voltage rating so that the power switch transistors206and208can handle the input surge voltage after the power switch transistors206and208turn off. As a result, the surge protector102prevents the voltage spike on the input from reaching downstream devices104connected to the surge protector102, in particular embodiments. The resistor218, the resistor220, and the Zener diode222are connected to the gate of the control transistor210. In certain embodiments, the resistor218, the resistor220, and/or the Zener diode222increase the impedance of the gate path of the control transistor210. As a result, the resistor218, the resistor220, and/or the Zener diode222limit the gate voltage of the control transistor210(e.g., to 15 volts), which protects the control transistor210from the voltage spike in the input. In some embodiments, the threshold voltage for turning on the control transistor210can be adjusted by adjusting the resistors218and220(e.g., replacing the resistors218and220with resistors with different resistances, or using variable resistors). In certain embodiments, the input impedance of the surge protector102is higher than 1 kiloOhm, which limits the surge current that the transistors206,208, and210experience. This impedance value can be increased if needed. Additionally, the Zener diodes216and222limit the surge voltage that the transistors206,208, and210experience. For example, circuit paths of the surge protector102may have a minimum impedance of 1 kiloOhm, which is high enough to protect the components of the surge protector102. The charge and discharge time constants in the circuit paths are high enough to provide high tolerance to input surge voltage and current. Moreover, because the surge protector102uses discrete components to provide surge protection, it is simple to adjust component values to suit different application requirements. These component values can be adjusted to provide even higher surge protection level if needed. As discussed previously, the surge protector102also provides other forms of electrical protection to downstream devices104connected to the surge protector102. For example, the surge protector102provides a polarity guard function. When the polarity of the electrical input power is reversed, the switch205blocks the input power with the reversed polarity. Specifically, the function of the power switch transistor206may be represented as a body diode226connected between the source and drain of the power switch transistor206, which blocks the reverse polarity input power. As a result, the surge protector102does not output the input power with the reversed polarity, which prevents the input power from reaching downstream devices104connected to the surge protector102. As another example, the surge protector102provides an inrush current limiting function. Because the power switch transistors206and208gradually turn on as the capacitor204charges to the charge threshold, the switch205prevents an inrush current over the input from reaching the output of the surge protector102. In some embodiments, it may take 10 milliseconds to charge the capacitor204, which provides enough time for the inrush current to settle down. As a result, when the power switch transistors206and208have turned on and are conducting the input power to the output of the surge protector102, the input power does not include the inrush current. Stated differently, because the switch205does not conduct the input power to the output of the surge protector102until the capacitor204has charged, the power switch transistors206and208prevent an inrush current over the input from being conducted to the output. In certain embodiments, the surge protector102includes an under voltage lockout (UVLO) circuit that protects downstream devices104from input power with voltages that are too low.FIG.2Billustrates an example UVLO circuit228that may be connected to the surge protector102ofFIG.2A. In the example ofFIG.2B, the input of the UVLO circuit228is connected to the output of the surge protector102shown inFIG.2A. Generally, the UVLO circuit228sets a lower limit for the voltage that the UVLO circuit228will conduct. As a result, if the voltage of the input power to the surge protector102falls below the voltage threshold set by the UVLO circuit228, then the UVLO circuit228blocks the input power and prevents it from reaching downstream devices104. When the voltage of the input power to the surge protector102exceeds the voltage threshold set by the UVLO circuit228, then the UVLO circuit228conducts the input power to downstream devices104. FIG.3is a flowchart of a method300performed in the system100ofFIG.1. In particular embodiments, the surge protector102performs the method300. By performing the method300, the surge protector102provides a polarity guard function that protects downstream devices104from inputs with reversed polarity. In block302, the surge protector102receives an electrical input power with an incorrect polarity. For example, the surge protector102may be configured to receive an electrical power with a certain polarity but instead receives a power with a reversed polarity. In block304, the surge protector102blocks the input power with the incorrect polarity. The surge protector102includes a power switch transistor206that blocks the input power with the incorrect polarity. Specifically, the function of the power switch transistor206is represented as a body diode226connected across the source and drain of the power switch transistor206. The body diode226blocks the input power with the reversed polarity. As a result, the power switch transistor206prevents the input power with the reversed polarity from reaching the output of the surge protector102. FIG.4is a flow chart of an example method400performed in the system100ofFIG.1. In particular embodiments, the surge protector102performs the method400. By performing the method400, the surge protector102provides an inrush current limiting function that protects downstream devices104connected to the surge protector102from inrush currents that occur when electrical power is initially provided to the surge protector102and/or the devices104. Additionally, by performing the method400, the surge protector102transitions from an off state to an on state in which the surge protector102conducts an electrical input power to its output. In block402, the surge protector102receives an electrical input power. A power source may have been recently connected or turned on to provide the input power. As a result, the input power may include an inrush current. In block404, the input power charges a capacitor204in the surge protector102. The capacitor204is connected to the input of the surge protector102by a resistor212. As a result, the capacitor204is charged by the input power through the resistor212. The resistance of the resistor212and the capacitance of the capacitor204affect the rate at which the capacitor204charges. In certain embodiments, the surge protector102includes a Zener diode214connected to the resistor212and the capacitor204. The Zener diode214sets a charge threshold above which the capacitor204does not charge. In some embodiments, it may take at least 10 milliseconds to charge the capacitor204to the charge threshold set by the Zener diode214. In block406, the power switch transistors206and208in the switch205gradually turn on as the capacitor204charges. For example, as the capacitor204charges, the voltage across the capacitor204increases. The gates of the power switch transistors206and208are connected to the capacitor204. As a result, the power switch transistors206and208gradually turn on as the voltage across the capacitor204gradually increases during charging. Thus, the power switch transistors206and208prevent the initial inrush current from being conducted to the output of the surge protector102. When the capacitor204has charged to the charge threshold set by the Zener diode214, the power switch transistors206and208are fully turned on and conduct the input power to the output of the surge protector102in block408. The time it takes for the capacitor204to charge to the charge threshold may provide sufficient time for the inrush current to settle down. As a result, the surge protector102prevents the inrush current from reaching downstream devices104connected to the surge protector102, in particular embodiments. In some embodiments, the sources of the power switch transistors206and208are connected together and the gates of the power switch transistors206and208are connected together, and the power switch transistors206and208turn on at the same time. FIG.5is a flow chart of an example method500performed in the system100ofFIG.1. In particular embodiments, the surge protector102performs the method500. By performing the method500, the surge protector102protects downstream devices104connected to the surge protector102from voltage surges, such as for example, surges caused by the lightning strikes. The method500may be performed after the method400(e.g., after the capacitor204is charged and the transistors206and208are turned on). In block502, the surge protector102receives a high voltage electrical input power. The high voltage input power includes a voltage surge that may damage downstream devices104connected to the surge protector102. For example, the high voltage input power may be caused by a lightning strike. In block504, the high voltage input power turns on a control transistor210. The surge protector102includes a Zener diode216connected to the input of the surge protector102. The Zener diode216sets a voltage threshold that, when exceeded by the voltage of the input power, causes the Zener diode216to conduct the input power to the gate of the control transistor210. As a result, the voltage surge in the high voltage input power is conducted to the gate of the control transistor210and turns on the control transistor210. When the control transistor210is turned on, the capacitor204begins discharging through a resistor224connected to the capacitor204and the drain of the control transistor210in block506. The resistance of the resistor224and the capacitance of the capacitor204affect how quickly the capacitor204discharges. When the capacitor204discharges, the power switch transistors206and208in the switch205, whose gates are connected to the capacitor204, turn off in block508. When the power switch transistors206and208turn off, the switch205stops conducting the high voltage input power to the output of the surge protector102. As a result, the surge protector102blocks the high voltage input power in block510. In this manner, the surge protector102prevents the voltage surge in the input power from reaching downstream devices104connected to the surge protector102. In some embodiments, the power switch transistors206and208turn off at the same time. In summary, a surge protector102uses transistors206,208, and210to protect electrical equipment from electrical surges (e.g., surges caused by lightning strikes). The surge protector102includes a capacitor204that charges using an input power to the surge protector102. When the capacitor204is charged to a charge threshold, the power switch transistors206and208turn on, which causes the surge protector102to output the input power. When a voltage surge occurs, the control transistor210turns on, which causes the capacitor204to discharge. When the capacitor204discharges to below the charge threshold, the power switch transistors206and208turn off, which causes the surge protector102to stop outputting the input power. As a result, the surge protector102prevents the surge from reaching downstream electrical equipment, in certain embodiments. Additionally, the surge protector102may also provide other forms of electrical protection (e.g., a polarity guard function and an inrush current limiting function). In the current disclosure, reference is made to various embodiments. However, the scope of the present disclosure is not limited to specific described embodiments. Instead, any combination of the described features and elements, whether related to different embodiments or not, is contemplated to implement and practice contemplated embodiments. Additionally, when elements of the embodiments are described in the form of “at least one of A and B,” or “at least one of A or B,” it will be understood that embodiments including element A exclusively, including element B exclusively, and including element A and B are each contemplated. Furthermore, although some embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the scope of the present disclosure. Thus, the aspects, features, embodiments and advantages disclosed herein are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the invention” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). In view of the foregoing, the scope of the present disclosure is determined by the claims that follow. | 20,877 |
11862967 | DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It will be understood that when an element is referred to as being “coupled” or “connected” to another element, it can be directly coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly coupled” or “directly connected” to another element, there are no intervening elements present. Like numbers refer to like elements throughout. In addition, spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. As used herein, “monolithic” means an object that is a single, unitary piece formed or composed of a material without joints or seams. Alternatively, a unitary object can be a composition composed of multiple parts or components secured together at joints or seams. As used herein, the term “wafer” means a substrate having a thickness which is relatively small compared to its diameter, length or width dimensions. With reference toFIGS.1-18, a modular overvoltage protection device or modular surge protective device (SPD) assembly module according to embodiments of the present invention is shown therein and designated101. In accordance with some embodiments, the SPD assembly module101is configured be connected to, and in electrical series between, two electrical lines in order to provide overvoltage protection to one of the lines. In some embodiments or applications, the SPD assembly module101is connected to each of an electrical ground PE (e.g., protective earth ground) and a protected electrical line L as represented inFIG.18. In some embodiments or applications, the line L is a voltage line of an electrical power circuit and, in some embodiments, is a voltage line of a multi-phase (e.g., three phase) electrical power circuit. In some embodiments or applications, the line L is a neutral line (N) of an electrical power circuit and, in some embodiments, is a neutral line of a multi-phase (e.g., three phase) electrical power circuit. The line L may be connected to the SPD assembly module101by a cable CL of the line L, and the protective earth PE may be connected to the SPD assembly module101by a cable CPE (FIGS.15-17). The SPD assembly module101and the cables CL, CPE collectively form an SPD installation assembly103A,103B, or103C when connected (FIGS.15-17). As discussed herein, the SPD assembly module101includes an overvoltage protection circuit. The SPD assembly module101and the cables CL, CPE form an overvoltage protected circuit12(FIG.18). In accordance with some embodiments, the SPD assembly module101is configured to be mounted on and secured to a substrate or support S (FIGS.1,5and15-17). The support S may be any suitable support surface, structure or platform. Suitable supports S may include, for example, a wall or shelf of a cabinet, a wall, floor or other structure of a building, or a component of an electrical power generator or electrical power generation station. In some embodiments, the SPD assembly module101is secured to the support S using one or more fasteners108(FIGS.1and5). In some embodiments, the SPD assembly module101is secured to the support S using an adhesive106(FIGS.3and5). In some embodiments, the SPD assembly module101is secured to the support S using one or more fasteners108and an adhesive106(FIG.5). As discussed herein, the SPD assembly module101is configured to provide alternative options for connecting a conductor or cable CL of the line L to the SPD assembly module101. The SPD assembly module101is configured to provide alternative options form affixing the SPD assembly module101to the support S. The SPD assembly module101is also configured to provide alternative options for orienting the SPD assembly module101on the support S. The SPD assembly module101is configured as a unit or module having a heightwise axis H-H (FIG.1), a lengthwise axis L-L perpendicular to the heightwise axis H-H, and a lateral or widthwise axis W-W perpendicular to the lengthwise axis L-L and perpendicular to the heightwise axis H-H. The SPD assembly module101includes an outer enclosure160, an SPD module100disposed and contained in the outer enclosure160, a first electrical terminal TPE, a second electrical terminal T2, a third electrical terminal T3, and a fourth electrical terminal T4(FIGS.1and3). The SPD assembly module101further includes a terminal busbar140(including the terminals T3and T4), a terminal bracket142, a first or PE cable assembly146(including the terminal TPE), a second or L/N cable assembly148(including the terminal T2), an insulator member144, a ground testing terminal assembly149, and a ground test cover168. The SPD module100(FIGS.3-5and10-12) is configured as a unit or module having a heightwise axis HI-HI (FIG.5) that is parallel to the axis H-H. The SPD module100includes a first electrode or housing electrode122, a piston-shaped second or inner electrode124, an end cover or cap126, end cap fasteners (screws)128, an elastomeric insulator member129, a meltable member132, an insulator sleeve134, a varistor member136, and a gas discharge tube (GDT)138. The SPD100may further include an integral fail-safe mechanism, arrangement, feature or system131(FIG.5). The fail-safe system131is adapted to prevent or inhibit overheating or thermal runaway of the overvoltage protection device, as discussed in more detail below. The housing electrode122, the inner electrode124, the end cap126, the end cap screws128, and the elastomeric insulator member129collectively form an SPD housing assembly121(FIG.11) defining an environmentally sealed, enclosed SPD chamber123(FIG.5). The varistor member136and the GDT138are disposed axially between the housing electrode122and the inner electrode124along the heightwise axis H-H, in the enclosed SPD chamber123. The varistor member136, the GDT138, and the meltable member132are contained in the enclosed SPD chamber123. The housing electrode122(FIG.12) has an end electrode wall122A and an integral cylindrical sidewall122B extending from the electrode wall122A. The sidewall122B and the electrode wall122A form a chamber or cavity122C communicating with an opening122D. The electrode wall122A has an inwardly facing, substantially planar contact surface122G. Threaded screw holes122H are defined in the upper end of the sidewall122B. According to some embodiments, the housing electrode122is formed of aluminum. However, any suitable electrically conductive metal may be used. According to some embodiments, the housing electrode122is unitary and, in some embodiments, monolithic. The housing electrode122as illustrated is cylindrically shaped, but may be shaped differently. The inner electrode124(FIG.12) has a head124A disposed in the cavity122C and an integral shaft122B that projects outwardly through the opening122D. The head124A has a substantially planar contact surface124C that faces the contact surface122G of the electrode wall122A. A pair of integral, annular, axially spaced apart flanges124D extend radially outwardly from the shaft124B and define an annular, sidewardly opening groove124E therebetween. A threaded bore124F is formed in the end of the shaft124B to receive a bolt for securing the electrode124to the terminal busbar140. According to some embodiments, the inner electrode124is formed of aluminum. However, any suitable electrically conductive metal may be used. According to some embodiments, the inner electrode124is unitary and, in some embodiments, monolithic. An annular gap is defined radially between the head124A and the nearest adjacent surface of the sidewall122B. According to some embodiments, the gap has a radial width in the range of from about 1 to 15 mm. The end cap126(FIG.12) is substantially plate-shaped and has a profile matching that of the top end of the housing electrode122. A shaft opening126A and screw holes126B are defined in the end cap126. According to some embodiments, the end cap126is formed of an electrically conductive material. In some embodiments, the end cap126is formed of a metal and, in some embodiments, are formed of aluminum. The meltable member132is annular and is mounted on the inner electrode124in the groove124E. The meltable member132is spaced apart from the sidewall122B a distance sufficient to electrically isolate the meltable member132from the sidewall122B. The meltable member132is formed of a heat-meltable, electrically conductive material. According to some embodiments, the meltable member132is formed of metal. According to some embodiments, the meltable member132is formed of an electrically conductive metal alloy. According to some embodiments, the meltable member132is formed of a metal alloy from the group consisting of aluminum alloy, zinc alloy, and/or tin alloy. However, any suitable electrically conductive metal may be used. According to some embodiments, the meltable member132is selected such that its melting point is greater than a prescribed maximum standard operating temperature. The maximum standard operating temperature may be the greatest temperature expected in the meltable member132during normal operation (including handling overvoltage surges within the designed for range of the system) but not during operation which, if left unchecked, would result in thermal runaway. According to some embodiments, the meltable member132is formed of a material having a melting point in the range of from about 80 to 160° C. and, according to some embodiments, in the range of from about 130 to 150° C. According to some embodiments, the melting point of the meltable member132is at least 20° C. less than the melting points of the housing electrode122and the inner electrode124and, according to some embodiments, at least 40° C. less than the melting points of those components. According to some embodiments, the meltable member132has an electrical conductivity in the range of from about 0.5×106Siemens/meter (S/m) to 4×107S/m and, according to some embodiments, in the range of from about 1×106S/m to 3×106S/m. According to some embodiments, the varistor member136is a varistor wafer (i.e., is wafer- or disk-shaped). In some embodiments, the varistor member136is circular in shape and has a substantially uniform thickness. However, the varistor member136may be formed in other shapes. The thickness and the diameter of the varistor member136will depend on the varistor characteristics desired for the particular application. In some embodiments, the SPD module100includes a plurality of the varistor members136axially stacked and captured between the inner electrode head124A and the end wall122A. In some embodiments, the varistor member136has a diameter D1to thickness T1ratio of at least 3. In some embodiments, the thickness T1(FIG.12) of the varistor member136is in the range of from about 0.5 to 15 mm. In some embodiments, the diameter D1(FIG.12) of the varistor member136is in the range of from about 20 to 100 mm. The varistor wafer136(FIG.12) has first and second opposed, substantially planar contact surfaces136U,136L and a peripheral edge136E. The varistor material may be any suitable material conventionally used for varistors, namely, a material exhibiting a nonlinear resistance characteristic with applied voltage. Preferably, the resistance becomes very low when a prescribed voltage is exceeded. The varistor material may be a doped metal oxide or silicon carbide, for example. Suitable metal oxides include zinc oxide compounds. The varistor wafer136may include a wafer of varistor material coated on either side with a conductive coating so that the exposed surfaces of the coatings serve as the contact surfaces136U,136L. The coatings can be metallization formed of aluminum, copper or silver, for example. Alternatively, the bare surfaces of the varistor material may serve as the contact surfaces136U,136L. The GDT138is wafer or disk-shaped and includes a body138A and opposed electrical terminals138B and138C on the major opposed faces of the body138A, and an annular electrical insulator (e.g., ceramic) surrounding the body138A between the terminals138B,138C. The body138A contains an anode, a cathode and a spark gap chamber as is known in the art. In some embodiments and as illustrated, the outer faces of the terminals138B,138C are substantially flat and planar or include a substantially flat or planar circular or annular contact region. According to some embodiments, the ratio of the diameter of the GDT138to its thickness is in the range of from about 4 to 15. According to some embodiments, the thickness of the GDT138is in the range of from about 3 mm to 8 mm. In some embodiments, the diameter of the GDT138is in the range of from about 20 mm to 40 mm. In some embodiments, the body138A includes a hermetically or gas-tight sealed chamber or cell in which a selected gas is contained. The terminals138B,138C are electrically connected to the gas (e.g., by respective electrode portions in fluid contact with the contained gas). Below a prescribed spark over the voltage, the GDT138is electrically insulating between the terminals138B,138C. When an applied voltage across the terminals138B,138C exceeds the prescribed spark over voltage, the contained gas is ionized to cause electrical current to flow through the gas (by the Townsend discharge process) and thereby between the terminals138B,138C. Thus, the GDT138will selectively electrically insulate or conduct, depending on the applied voltage. The voltage required to initiate and sustain electrical conduction (discharge) will depend on the design characteristics of the GDT138(e.g., geometry, gas pressure, and gas composition). In some embodiments, the GDT138has surge current and energy withstand capabilities at least as great as those of the MOV varistor wafer136(combined) used in series with the GDT138. Suitable GDTs may include a flat type GDT with rated voltage from 1000 to 2000 volts. The insulator sleeve134is tubular and generally cylindrical. According to some embodiments, the insulator sleeve134is formed of a high temperature polymer and, in some embodiments, a high temperature thermoplastic. In some embodiments, the insulator sleeve134is formed of polyetherimide (PEI), such as ULTEM™ thermoplastic available from SABIC of Saudi Arabia. In some embodiments, the insulator member134is formed of non-reinforced polyetherimide. According to some embodiments, the insulator sleeve134is formed of a material having a melting point greater than the melting point of the meltable member132. According to some embodiments, the insulator sleeve134is formed of a material having a melting point in the range of from about 120 to 200° C. According to some embodiments, the insulator sleeve134material can withstand a voltage of 25 kV per mm of thickness. According to some embodiments, the insulator sleeve134has a thickness in the range of from about 0.1 to 2 mm. The elastomeric insulator member129(FIGS.5and12) is annular and includes a shaft opening129A. The elastomeric insulator member129includes an annular main body129B, an integral, annular upper flange129C and an integral, annular lower flange129D. The elastomeric insulator member129is formed of an electrically insulating, resilient, elastomeric material. According to some embodiments, the elastomeric insulator member129is formed of a material having a hardness in the range of from about 60 Shore A to 85 Shore A. According to some embodiments, the elastomeric insulator member129is formed of rubber. According to some embodiments, the elastomeric insulator member129is formed of silicone rubber. Suitable materials for the elastomeric insulator member129may include silicone rubber having a Shore hardness 0-10 up to D-0 and, in some embodiments, Shore A50or Shore A60. The main body129B of the elastomeric insulator member129is captured axially between the end cap126and the electrode upper flange124D. The upper flange129C extends through the end cap opening126A and the shaft124B of the electrode124extends through the opening129A, so that the upper flange129C fills the circumferential gap between the shaft124B and the end cap126. The lower flange129D surrounds the electrode flange124D so that the lower flange129D fills the circumferential gap between the electrode flange124D and the electrode sidewall122B. The insulator member129serves to electrically insulate the housing electrode122from the inner electrode124. The compressed insulator member129can also form a seal to constrain or prevent overvoltage event byproducts, such as hot gases and fragments from the varistor wafers of the varistor member136from escaping the enclosed chamber123through the housing electrode opening122D. The main body129B of the elastomeric insulator member129is captured between the end cap126and the electrode upper flange124D and axially compressed (i.e., axially loaded and elastically deformed from its relaxed state) so that the insulator member129serves as a biasing member and applies a persistent axial pressure or load to the inner electrode124and the end cap126. The elastomeric insulator member129thereby persistently biases or loads the electrode head124A and the housing end wall122A against the varistor member136and the GDT138along a load or clamping axis C-C (FIG.12) in convergent directions to ensure firm and uniform engagement between the interfacing contact surfaces of the head124A, the end wall122A, the varistor member136, and the GDT138. This aspect of the SPD module100may be appreciated by considering a method according to the present invention for assembling the SPD module100, as described below. In some embodiments, the clamping axis C-C is substantially coincident with the axis HI-HI. The insulator sleeve134is slid into the housing cavity122C. The varistor member136and the GDT138are placed in the cavity122C such that the terminal138C of the GDT138the contact surface122G of the end wall122A, and engages the contact surface136L of the varistor member136engages the terminal138B of the GDT138. The head124A is inserted into the cavity122C such that the contact surface124C engages the upper contact surface136U of the varistor member136. The elastomeric insulator member129is slid over the shaft124B. The end cap126is then slid over the shaft124B and the elastomeric insulator member129and secured to the housing electrode122by the bolts128. The end cap126axially compresses the elastomeric insulator member129. With reference toFIG.11, the L/N terminal busbar140includes a U-shaped body140A, an integral first or left terminal structure140L, and an integral second or right terminal structure140R. The terminal structures140L,140R are tabs that are rigidly connected to the body140A and project in opposing directions therefrom. The body140A is mechanically and electrically connected to the electrode124by a fastener141. In some embodiments, the body140A is secured in electrical contact with the electrode124by the fastener141. Mount holes140C are provided in the terminal tabs140L,140R. The mount holes140C may be threaded or provided with fixed nuts140E. A threaded connection stud140D is affixed to and projects from the body140A. The L/N terminal busbar140may be formed of any suitable electrically conductive metal. According to some embodiments, the L/N terminal busbar140is formed of aluminum. According to some embodiments, the L/N terminal busbar140is unitary and, in some embodiments, monolithic. With reference toFIG.11, the PE bracket142includes a body142A and a leg142C depending from the body142A. Mount holes142B are provided in the body142A. A threaded connection stud142D is affixed to and projects from the leg142C. The body142A is mechanically and electrically connected to the housing electrode122by fasteners143. In some embodiments, the body140A is secured in electrical contact with the end cap126by the fasteners143. The body140A is thereby electrically connected to the housing electrode122. The PE bracket142may be formed of any suitable electrically conductive metal. According to some embodiments, the PE bracket142is formed of aluminum. According to some embodiments, the PE bracket142is unitary and, in some embodiments, monolithic. With reference toFIG.11, the busbar insulator member144includes a U-shaped body144A and a hole144B sized to receive the end of the electrode shaft124B. The busbar insulator member144is interposed and clamped between the busbar140and the end cap126. The busbar insulator member144thereby electrically insulates or isolates the busbar140from the housing electrode122. The busbar insulator member144may be formed of any suitable rigid, electrically insulating material. According to some embodiments, the busbar insulator member144is formed of polypropylene. With reference toFIG.11, the PE terminal assembly146includes a flexible, electrically insulated electrical cable146A, an inner connector termination146B and an outer connector termination146C. The connector terminations146B,146C may be metal connector lugs. The outer connector termination146C serves as a terminal structure for connecting the SPD module100to a PE line. The ends of the insulation of the cable146A are environmentally sealed about the connector terminations146B,146C by polymeric tubes146D. In some embodiments, the end seals are water-tight. The cable146A may be an electrical cable of any suitable type or construction. As illustrated inFIG.13, the cable146A includes an electrical conductor146K surrounded by a tubular polymeric insulation layer1461. Suitable cables may include silicone rubber-insulated cables, PTFE-insulated cables, cross-linked polyolefic-copolymer-insulated cables, ethylene tetraflouroethylene (ETFE) insulated cables, cross-linked ETFE-insulated cables, and polyimide-insulated cables. The tubes146D may be formed of any suitable material. In some embodiments, the tubes146D are formed of an electrically insulating polymeric material. In some embodiments, the tubes146D are formed of an electrically insulating elastomeric material. In some embodiments, the tubes146D are formed of an electrically insulating heat shrinkable polymer (e.g., elastomer) that has been heat shrunk about the corresponding cable insulation and connector termination. In other embodiments, the tubes146D are cold shrinkable elastomeric tubes. In other embodiments, a sealant or gasket may be used in place of or in addition to the sealing tubes146D. The connector termination146B is electrically and mechanically connected to the PE bracket142by the stud142D and a nut145. The outer connector termination146C is thereby electrically connected to the electrode housing122. With reference toFIG.11, the L/N terminal assembly148includes a flexible, electrically insulated electrical cable148A, an inner connector termination148B and an outer connector termination148C. The connector terminations148B,148C may be metal connector lugs. The outer connector termination148C serves as a terminal structure for connecting the SPD module100to a line L or a neutral line N. The ends of the insulation of the cable148are environmentally sealed about the connector terminations148B,148C by polymeric tubes148D. In some embodiments, the end seals are water-tight. The L/N terminal assembly148may be constructed in the same manner as described above for the PE terminal assembly146. The connector termination148B is electrically and mechanically connected to the L/N terminal busbar140by the stud140D and a nut145. The outer connector termination148C is thereby electrically connected to the inner electrode124. With reference toFIG.11, the ground testing terminal assembly149includes an electrically insulated electrical wire149A, an inner connector termination149B (e.g., a lug connector), and a contact termination149C. The contact termination149C has a contact surface or face149D. The connector termination149B is electrically and mechanically connected to the PE bracket142by a fastener143. The contact termination149C is thereby electrically connected (via the wire149A) to the electrode housing122. With reference toFIGS.1-9,13and14, the enclosure160includes a first or left shell162, a second or right shell164, coupling screws26, and a test cover168. The shells162,164are mated at an environmentally sealed interface167. The shells162,164collectively form an environmentally sealed enclosure chamber166(FIG.4). In some embodiments, the chamber166is sealed water-tight. The shell162(FIG.7) defines a cavity162A and an opening162B. The shell164(FIGS.8and9) defines a cavity164A and an opening164B. Each shell162,164includes a top wall172A, a bottom wall172B, and opposed end walls172C,172D. The shell162further includes a first or left side wall172E. The shell164further includes a second or right side wall172F. Each shell162,164includes integral mount tabs174at its top and bottom and front and rear corners. A pair of vertically stacked and aligned, spaced apart tabs174are thereby provided at each corner of the enclosure. Each mount tab174includes a mount hole174A. Each shell162,164includes integral locator features178protruding into their cavities162A,164A. The locator features178may take any suitable forms, including elongate ribs as illustrated. Screw mounts175are defined in each shell162,164to receive the screws26to clamp the shells162,164together. The shell162includes a circumferential end flange162C that is received in a circumferential end groove164C of the shell164to help form the environmental seal. In some embodiments, the flange162C fits snugly or with an interference fit in the groove164C. The left shell162(FIG.7) includes a termination tab opening P4surrounded by an annular flange162F (FIG.3). The left shell162also includes a test port162G (FIGS.3and14) in which the contact termination149C is mounted such that the contact surface149D is exposed outside the shell162. The interface between the contact termination149C and the test port162G is sealed such that the test port162G is sealed fluid or water tight. For example, the contact termination149C may be secured in the test port162G with adhesive and/or an interference fit. The test cover168is mounted on the shell162to be displaceable relative to the shell162such that it can be selectively moved to expose the contact surface149D. In some embodiments, the test cover168is slidably mounted in a test cover slot162H (FIG.3) of the shell162. The right shell164(FIGS.8and9) includes a termination tab opening P3surrounded by a flange164F, a PE cable opening PPE surrounded by an annular flange164G, and an L/N cable opening P2surrounded by an annular flange164H. The shells162,164may be formed of any suitable material(s). In some embodiments, the shells162,164are formed of an electrically insulating material. In some embodiments, the shells162,164are formed of a polymeric material. The material of the shelles162,164may be selected from the group consisting of polysulphone (PSU), polyethersulphone (PESU), and polyphenylsulphone (PPSU) (e.g., with 5-15% fiber glass or without fiber glass addition). In some embodiments, the shells162,164are formed of a flame retardant polymeric material. In some embodiments, the shells162,164are formed of a polymeric material having a temperature resistance of at least 100 degrees Celsius. The test cover168may be formed of the same material as described for the shells162,164, or another electrically insulating material. Indicia179is provided on the enclosure160to indicate (e.g., for an installer) the purpose of each corresponding terminal TPE, T2, T3, T4. The indicia179may be embossed, printed or otherwise provided on the enclosure160. The SPD module100, the terminal busbar140, the terminal bracket142, the PE cable assembly146, the L/N cable assembly148, the insulator member144, the ground testing terminal assembly149, and the associated fasteners form an electrical subassembly105. The electrical subassembly105is disposed in the enclosure housing160such that the SPD module100is contained in the enclosure chamber166and the terminal tabs140L,140R, the PE cable assembly146, and the L/N cable assembly148extend out of the enclosure160through the openings PPE, P2, P3, P4. More particularly, the terminal tab140L extends through the opening P3, the terminal tab140R extends through the opening P4, the PE cable assembly146extends through the opening PPE, and the L/N cable assembly148extends through the opening P2. With reference toFIGS.2,9and13, the openings PPE and P2are environmentally sealed about the cables146A and148A by polymeric tubes150. In some embodiments, these openings are sealed water-tight by the tubes150. The tubes150may be formed of any suitable material. In some embodiments, the tubes150are formed of an electrically insulating polymeric material. In some embodiments, the tubes150are formed of an electrically insulating elastomeric material. In some embodiments, the tubes150are formed of an electrically insulating heat shrinkable polymer (e.g., elastomer) that has been heat shrunk about the corresponding cable insulation and termination. With reference toFIGS.1-3, the openings P3and P4are environmentally sealed about the terminals T3and T4(e.g., about the terminal tabs140L and140R) by masses of epoxy152. In some embodiments, the openings P3and P4are sealed water-tight by the epoxy152. The epoxy152may be formed of any suitable material. The SPD assembly module101is configured to minimize or prevent movement or vibration of the SPD module100relative to the enclosure160. As shown inFIGS.3and4-9, the SPD module100and other components of the electrical subassembly105are snugly or tightly captured in the enclosure by abutments between those components and the walls172A-172F of the shells162,164and the locator features178of the shells162,164. As shown inFIG.8, the terminals T3and T4are attached to the plastic enclosure160through the openings P3, P4by the epoxy152, which additionally prevents or inhibits movement or vibration of the SPD module100with respect to the enclosure160. The PE termination cable146A and its termination146C serve as the PE terminal TPE. The L/N termination cable148and its termination148C serve as a first L/N terminal T2. The terminal tab140R serves as a second L/N terminal T3. The terminal tab140L serves as a third L/N terminal T4. The terminals TPE, T2, T3, T4are designated by the indicia179. The PE termination cable146A, the L/N termination cable148, and the L/N terminal tab140R extend outward from the right side MR (FIG.6) of the enclosure160generally in a first direction DR. The terminal tab140L extends outward from the opposing left side ML of the enclosure160generally in a second direction DL. Thus, as shown inFIGS.6and15, the L/N terminals T2, T3project outwardly from the same side of the enclosure160, and the L/N terminal T4projects outwardly from the opposite side of the enclosure160. The terminal tabs140L,140R are substantially rigidly mounted on the enclosure160. The L/N termination cable148A is flexible, so that the terminal T2is flexibly mounted on the enclosure160. The SPD assembly module101may be used as follows in accordance with some methods. The SPD assembly module101is secured or affixed to a support S (FIGS.1,5and15-17). In some embodiments, the SPD assembly module101is secured to the support S using fasteners108(e.g. screws, bolts, nuts, and/or rivets) that are inserted through the openings174A and into or through the support S as shown inFIG.5, for example. In some embodiments, the SPD assembly module101is secured to the support S using an adhesive106that is applied between the top or bottom wall172A,172B of the enclosure160and the support S to bond the enclosure160to the support S (as shown inFIG.5, for example). In some embodiments, the SPD assembly module101is secured to the support S using both the fasteners108and the adhesive106(FIG.5). The adhesive106may be any suitable type of adhesive. In some embodiments, the adhesive106is a cyanoacrylate-based adhesive. In some embodiments, the adhesive106is an epoxy. The SPD assembly module101is also configured to provide alternative options for orienting the SPD assembly module101on the support S. The SPD assembly module101can be affixed to the support S with either the top wall172A or the bottom wall172B facing the support S. The SPD assembly module101can be affixed to the support S with the left side ML and the right side MR reversed. The installer will connect the system PE cable CPE to the PE termination cable146A to connect the system PE cable CPE to the housing electrode122of the SPD module100. For example, the installer can secure a connector termination32of the system PE cable CPE to the connector termination146C using a fastener (e.g., bolt) as shown inFIG.15. The installer can choose from multiple alternative options or configurations for terminating the system line or neutral cable CL (hereinafter, the “system L/N cable CL”) to the to the inner electrode124of the SPD module100. In accordance with a first option, an SPD installation assembly103A is assembled in a first configuration as shown inFIG.15. In the first configuration, the installer secures a connector termination34of the system L/N cable CL to the connector termination148C using a fastener (e.g., bolt). In accordance with a second option, an SPD installation assembly103B is assembled in a second configuration as shown inFIG.16. In the second configuration, the installer secures the connector termination34of the system L/N cable CL to the right side termination tab140R using a fastener (e.g., bolt). In accordance with a third option, an SPD installation assembly103C is assembled in a third configuration as shown inFIG.17. In the third configuration, the installer secures the connector termination34of the system L/N cable CL to the left side termination tab140L using a fastener (e.g., bolt). FIG.18illustrates the three alternative electrical circuit configurations formed by the three configurations discussed above. The alternative connections between the line L and the terminals T2, T3, and T4are illustrated with dashed lines. It will be appreciated that these three options and configurations provide the installer with the flexibility to terminate the system L/N cable CL on either the left or right side of the enclosure160. It will be appreciated that these three options and configurations provide the installer with the flexibility to terminate the system L/N cable CL on the same side or the opposite of the enclosure160from the termination of the system PE cable CPE. It will also be appreciated that these three options and configurations provide the installer with the flexibility to terminate the system L/N cable CL to a flexible terminal (i.e., the terminal T2) or to a rigid terminal (i.e., the terminal T3or the terminal T4). In some embodiments, the connection joints between the cable connectors32,34and the terminals146C,148C,140R,140L are also covered and environmentally sealed to prevent exposure of the connection joints to water or contaminants. These connection joints may also be covered with polymeric tubes constructed as described for the tubes150, such as heat shrink tube. The SPD assembly module101can provide a number of advantages in use. The SPD assembly module101may be particularly well-suited for use in applications where it is subjected to harsh environmental conditions such as extreme temperatures, moisture, vibration, impacts, and other mechanical forces. The SPD assembly module101may be particularly well-suited for use in applications in which mounting flexibility and termination flexibility are desirable or necessary. The external plastic housing or enclosure160provides an environmental barrier surrounding the SPD module100and other components and connections of the electrical subassembly105. As described herein, fluid tight seals are provided about each of the shells interface167, the ground test port162G, and the terminal openings PPE, P2, P3, P4. The sealed enclosure160can prevent ingress of humidity, other moisture, and contaminants into the enclosure chamber166. The enclosure160and terminal opening seals prevent or reduce the exposure of the SPD module100and the connections between the SPD module100and the terminal busbar140, the PE bracket142, and the connectors in the enclosure chamber166to moisture or other contaminants. In this way, the enclosure160can prevent or inhibit corrosion of the electrical components enclosed. Also, in this way, the enclosure160can prevent the intrusion of moisture that may undesirably short circuit electrical components of the electrical subassembly105. According to some embodiments, the enclosure chamber166is environmentally sealed in compliance with IP67 rating, version as per the International Electrotechnical Commission (IEC) 60529:1989+AMD1:1999+AMD2:2013. The enclosure160also provides mechanical protection for the SPD module100and the connections. The SPD housing assembly121of the SPD module100is robust and protects the internal components and assembly of the SPD module100from moisture, contaminants, and mechanical damage. The manner in which the terminals TPE, T2, T3, T4are connected to the SPD module100is also robust to resist dislocations from vibration (including multi-axis vibration and random, sinusoidal or shock vibration stress), thermal expansion, and other forces. It will be appreciated that the SPD assembly module101includes an inner sealed SPD housing assembly121containing the varistor136and GDT138, contained within a second, outer enclosure160. This construction can provide two levels of protection against expulsion of varistor failure byproducts from the SPD module100to the environment. The snug fitment between the enclosure160and the electrical subassembly105can prevent or inhibit relative movement or vibration between the enclosure160and the electrical subassembly105. This can reduce the risk of damage or deterioration of the internal components and connections of the SPD assembly module101. When the outer enclosure160and the cable assemblies146,148are formed of materials as described above, the SPD assembly module101may be particularly well-suited to withstand high temperatures (e.g., up to 120 deg Celsius) and very low temperatures (e.g., down to −40 deg Celsius) in prolonged service without failure. As discussed above, the arrangement of the terminals T2, T3, T4provides the installer or installation designer with bilateral termination options. As discussed above, the arrangement of the terminals T2, T3, T4provides the installer or installation designer with the option to choose between connection to a rigid or fixed terminal (i.e., terminal T3or T4) and connection to a flexible cable (i.e., terminal T2). As discussed above, the configuration of the enclosure160enables the use of alternative mounting techniques, including mounting to a support using fasteners, using adhesive, or using both. The installer can select the preferred mounting method(s) depending on the application. The sealed ground test contact149C provides a convenient feature for testing the electrical continuity between the housing electrode122of the SPD module100and the ground or protective earth PE without breaching the sealed chamber166. The slidable cover168shields the ground test contact from inadvertent contact when not in use. In the assembled SPD module100, the large, planar contact surfaces of the components122A,124A,136,138can ensure reliable and consistent electrical contact and connection between the components during an overvoltage or surge current event. The head124A and the end wall122A are mechanically loaded against these components to ensure firm and uniform engagement between the mating contact surfaces. The meltable member132and the electrodes122,124are relatively constructed and configured to form the fail-safe system131. The fail-safe system131provides a safe failure mode for the SPD module100. During use, the varistor wafer136or the GDT138may be damaged by overheating and may generate arcing inside the SPD housing assembly121. The SPD housing assembly121can contain the damage (e.g., debris, gases and immediate heat) within the SPD module100, so that the SPD module100fails safely. In this way, the SPD module100can prevent or reduce any damage to adjacent equipment (e.g., switch gear equipment in the cabinet) and harm to personnel. In this manner, the SPD module100can enhance the safety of equipment and personnel. Additionally, the SPD module100provides a fail-safe mechanism in response to end of life mode in the varistor wafer136. In case of a failure of the varistor wafer136, a fault current will be conducted between the corresponding line and the neutral line. As is well known, a varistor has an innate nominal clamping voltage VNOM (sometimes referred to as the “breakdown voltage” or simply the “varistor voltage”) at which the varistor begins to conduct current. Below the VNOM, the varistor will not pass current. Above the VNOM, the varistor will conduct a current (i.e., a leakage current or a surge current). The VNOM of a varistor is typically specified as the measured voltage across the varistor with a DC current of 1 mA. As is known, a varistor has three modes of operation. In a first normal mode (discussed above), up to a nominal voltage, the varistor is practically an electrical insulator. In a second normal mode (also discussed above), when the varistor is subjected to an overvoltage, the varistor temporarily and reversibly becomes an electrical conductor during the overvoltage condition and returns to the first mode thereafter. In a third mode (the so-called end of life mode), the varistor is effectively depleted and becomes a permanent, non-reversible electrical conductor. The varistor also has an innate clamping voltage VC (sometimes referred to as simply the “clamping voltage”). The clamping voltage VC is defined as the maximum voltage measured across the varistor when a specified current is applied to the varistor over time according to a standard protocol. In the absence of an overvoltage condition, the varistor wafer136provides high resistance such that no current flows through the SPD module100as it appears electrically as an open circuit. That is, ordinarily the varistor passes no current. In the event of an overcurrent surge event (typically transient; e.g., lightning strike) or an overvoltage condition or event (typically longer in duration than an overcurrent surge event) exceeding VNOM, the resistance of the varistor wafer decreases rapidly, allowing current to flow through the SPD module100and create a shunt path for current flow to protect other components of an associated electrical system. Normally, the varistor recovers from these events without significant overheating of the SPD module100. Varistors have multiple failure modes. The failure modes include: 1) the varistor fails as a short circuit; and 2) the varistor fails as a linear resistance. The failure of the varistor to a short circuit or to a linear resistance may be caused by the conduction of a single or multiple surge currents of sufficient magnitude and duration or by a single or multiple continuous overvoltage events that will drive a sufficient current through the varistor. A short circuit failure typically manifests as a localized pinhole or puncture site (herein, “the failure site”) extending through the thickness of the varistor. This failure site creates a path for current flow between the two electrodes of a low resistance, but high enough to generate ohmic losses and cause overheating of the device even at low fault currents. Sufficiently large fault current through the varistor can melt the varistor in the region of the failure site and generate an electric arc. A varistor failure as a linear resistance will cause the conduction of a limited current through the varistor that will result in a buildup of heat. This heat buildup may result in catastrophic thermal runaway and the device temperature may exceed a prescribed maximum temperature. For example, the maximum allowable temperature for the exterior surfaces of the device may be set by code or standard to prevent combustion of adjacent components. If the leakage current is not interrupted at a certain period of time, the overheating will result eventually in the failure of the varistor to a short circuit as defined above. In some cases, the current through the failed varistor could also be limited by the power system itself (e.g., ground resistance in the system or in photo-voltaic (PV) power source applications where the fault current depends on the power generation capability of the system at the time of the failure) resulting in a progressive build up of temperature, even if the varistor failure is a short circuit. There are cases where there is a limited leakage current flow through the varistor due to extended in time overvoltage conditions due to power system failures, for example. These conditions may lead to temperature build up in the device, such as when the varistor has failed as a linear resistance and could possibly lead to the failure of the varistor either as a linear resistance or as a short circuit as described above. As discussed above, in some cases the SPD module100may assume an “end of life” mode in which the varistor wafer136is depleted in full or in part (i.e., in an “end of life” state), leading to an end of life failure. When the varistor reaches its end of life, the SPD module100will become substantially a short circuit with a very low but non-zero ohmic resistance. As a result, in an end of life condition, a fault current will continuously flow through the varistor even in the absence of an overvoltage condition. In this case, the meltable member132can operate as a fail-safe mechanism that by-passes the failed varistor and creates a permanent low-ohmic short circuit between the terminals of the SPD module100in the manner described in U.S. Pat. No. 7,433,169, the disclosure of which is incorporated herein by reference. The meltable member132is adapted and configured to operate as a thermal disconnect to electrically short circuit the current applied to the associated SPD module100around the varistor wafer136to prevent or reduce the generation of heat in the varistors. In this way, the meltable member132can operate as switch to bypass the varistor wafer136and prevent overheating and catastrophic failure as described above. As used herein, a fail-safe system is “triggered” upon occurrence of the conditions necessary to cause the fail-safe system to operate as described to short circuit the electrodes122A,124A. When heated to a threshold temperature, the meltable member132will flow to bridge and electrically connect the electrodes122A,124A. The meltable member132thereby redirects the current applied to the SPD module100to bypass the varistor wafer136so that the current induced heating of the varistor ceases. The meltable member132may thereby serve to prevent or inhibit thermal runaway (caused by or generated in the varistor wafer136) without requiring that the current through the SPD module100be interrupted. More particularly, the meltable member132initially has a first configuration as shown inFIGS.4,5and12such that it does not electrically couple the electrode124and the housing122except through the head124A. Upon the occurrence of a heat buildup event, the electrode124is thereby heated. The meltable member132is also heated directly and/or by the electrode124. During normal operation, the temperature in the meltable member132remains below its melting point so that the meltable member132remains in solid form. However, when the temperature of the meltable member132exceeds its melting point, the meltable member132melts (in full or in part) and flows by force of gravity into a second configuration different from the first configuration. The meltable member132bridges or short circuits the electrode124to the housing122to bypass the varistor wafer136. That is, a new direct flow path or paths are provided from the surface of the electrode124to the surface of the housing sidewall122B through the meltable member132. According to some embodiments, at least some of these flow paths do not include the varistor wafer136. According to some embodiments, the SPD module100is adapted such that when the meltable member132is triggered to short circuit the SPD module100, the conductivity of the SPD module100is at least as great as the conductivity of the feed and exit cables connected to the device. Electrical protection devices according to embodiments of the present invention may provide a number of advantages in addition to those mentioned above. The devices may be formed so to have a relatively compact form factor. The devices may be retrofittable for installation in place of similar type surge protective devices not having circuits as described herein. In particular, the present devices may have the same length dimension as such previous devices. According to some embodiments, the biased electrodes (e.g., the electrodes122and124) apply a load to the varistors along the axis C-C in the range of from 2000 lbf and 26000 lbf depending on its surface area. In alternative embodiments (not shown), the SPD module100may be modified to use biasing or loading means such as metal spring washers and separate sealing means such as elastomeric O-rings. According to some embodiments, the combined thermal mass of the housing (e.g., the housing122) and the electrode (e.g., the electrode124) is substantially greater than the thermal mass of each of the varistors captured therebetween. The greater the ratio between the thermal mass of the housing and electrodes and the thermal mass of the varistors, the better the varistors will be preserved during exposure to surge currents and TOV events and therefore the longer the lifetime of the SPD. As used herein, the term “thermal mass” means the product of the specific heat of the material or materials of the object multiplied by the mass or masses of the material or materials of the object. That is, the thermal mass is the quantity of energy required to raise one gram of the material or materials of the object by one degree centigrade times the mass or masses of the material or materials in the object. According to some embodiments, the thermal mass of at least one of the electrode head and the electrode wall is substantially greater than the thermal mass of the varistor. According to some embodiments, the thermal mass of at least one of the electrode head and the electrode wall is at least two times the thermal mass of the varistor, and, according to some embodiments, at least ten times as great. According to some embodiments, the combined thermal masses of the head and the electrode wall are substantially greater than the thermal mass of the varistor, according to some embodiments at least two times the thermal mass of the varistor and, according to some embodiments, at least ten times as great. While the SPD module100has been shown and described including a varistor wafer136and a GDT138, in other embodiments the GDT138may be omitted. In some embodiments, the ground testing terminal assembly149and the test cover168may be omitted. In some embodiments, the flexible PE cable assembly146and/or the flexible L/N cable assembly148, may be replaced with a rigid busbar including terminal tabs corresponding to the terminal tabs140R,140L and projecting through and out of the enclosure160in the same manner as the terminal tabs140R,140L. Many alterations and modifications may be made by those having ordinary skill in the art, given the benefit of present disclosure, without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of example, and that it should not be taken as limiting the invention as defined by the following claims. The following claims, therefore, are to be read to include not only the combination of elements which are literally set forth but all equivalent elements for performing substantially the same function in substantially the same way to obtain substantially the same result. The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and also what incorporates the essential idea of the invention. | 55,386 |
11862968 | DETAILED DESCRIPTION The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated90degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. The present disclosure provides various embodiments of an ESD protection circuit and method that improve protection of ESD-sensitive circuits. In some embodiments, during an ESD event (e.g., in response to an ESD pulse applied at a pad coupled to a first transistor and a second transistor), a stack of transistors and an ESD clamp coupled to a gate of the first transistor are enabled. In some embodiments, after the stack of transistors and the ESD clamp are enabled, a gate voltage of the first transistor tracks a ground voltage. That is, the stack of transistors and the ESD clamp may cause a voltage of the gate of the first transistor to be a fixed voltage offset from the ground. In some embodiments, during the ESD event, a parasitic negative-positive-negative (NPN) bipolar transistor in the substrate of the first and second transistors turns on and discharges current from the ESD pulse. In some embodiments, the mechanism by which the parasitic NPN transistor discharges current is gate-induced drain leakage (GIDL), which is dependent on the voltage at the gate of the first transistor. In some embodiments, because the gate voltage of first transistor tracks the ground voltage, the voltage of the gate of the first transistor is lower than when the gate voltage of first transistor tracks the pad voltage. This means that, via the GIDL mechanism, the parasitic NPN transistor in the substrate of the first and second transistors can discharge more current than when the gate voltage of the first transistor tracks the pad voltage. Advantageously, embodiments of the disclosed memory circuit, method, and device can achieve several benefits. By discharging more current via the substrate, the ESD protection circuit can reduce a voltage across the pad and the ground during an ESD event, and, ultimately, across ESD-sensitive circuits coupled between the pad and the ground during the ESD event. The reduction in the voltage is with respect to embodiments that lack the stack of transistors and the ESD clamp. Thus, the ESD protection circuit more effectively protects ESD-sensitive circuits compared to embodiments that lack the improvements disclosed herein. FIG.1illustrates an electrostatic discharge (ESD) protection circuit100, in accordance with some embodiments of the present disclosure. The ESD protection circuit100can designed, configured, and operated to improve ESD protection of an ESD-sensitive circuit by reducing a voltage that can be generated across two terminals of the ESD-sensitive circuit during an ESD event. The ESD-sensitive circuit can be a memory circuit, a logic circuit, or any circuit sensitive to an ESD event. The ESD protection circuit100and the ESD-sensitive circuit can be a part of a same integrated circuit (IC), die, three-dimensional die (3D-die), system-on-a-chip (SoC), module, or printed circuit board (PCB) assembly. The ESD protection circuit100includes a transistor N1 coupled to a pad P1. The pad P1can be an input/output (I/O) pad. The transistor N1 can be referred to as a device or transistor device. The pad P1may be referred to as a pad terminal, an I/O terminal, or an I/O node. In some embodiments, the ESD protection circuit100is part of a high voltage tolerant IC design where the ESD protection device is rated higher than process specified operation voltage. In some embodiments, the transistor N1 may be rated for a first voltage, whereas the ESD protection device, as well as other circuits coupled between the pad P1and ground, may be rated for a second voltage that is higher than the first voltage. In other words, an operation voltage of the transistor N1 may be lower than an operational voltage for the pad P1. In some embodiments, a ratio of an operation voltage of the transistor N1 and an operation voltage of the pad P1is 0.85, less than 0.85, 0.7, less than 0.7, 0.5, less than 0.5, or any other value or range between 0 and 1. In some embodiments, the transistor N1 is rated for 1.2V (e.g., N1 is a process specified 1.2V device) and the pad P1is rated for 1.8V. The transistor N1 and the pad P1can be rated for any other voltage values or ranges without departing from the scope of the present disclosure. The transistor N1 can be a metal-oxide semiconductor field-effect transistor (MOSFET), an n-type MOSFET (an NMOS transistor), a p-type MOSFET (a PMOS transistor), a silicon-on-insulate (SOI) MOSFET, a bipolar junction transistor (BJT), or any other transistor suitable for use in memory structures. An NMOS transistor can be chosen for the transistor N1 for applications where speed is a concern because, in some embodiments, read and write operations are faster using an NMOS transistor than using a PMOS transistor. Specifically, in some embodiments, the mobility of electrons, which are carriers in the case of an NMOS transistor, is about two times greater than that of holes, which are the carriers of the PMOS transistor. A PMOS transistor can be chosen for the transistor N1 for applications where variation, cost, or noise is a concern because, in some embodiments, PMOS technology is highly controllable, low-cost process with good yield and high noise immunity as compared to NMOS technology. The transistor N1 can be any of various transistor types while remaining within the scope of the present disclosure. The transistor N1 can have a MOSFET device type of standard threshold voltage (SVT), low threshold voltage (LVT), high threshold voltage (HVT), high voltage (HV), input/output (IO), or any of various other MOS device types. The transistor N1 includes a number of ports. Each of the ports can also be referred to as a terminal. The transistor N1 can include a drain port, a source port, a gate port, and a body port. The drain port of the transistor N1 can be coupled to the pad P1. The source port of the transistor N1 can be coupled to a transistor N2, which is described below. The gate port of the transistor N1 can be coupled to a circuit CKTA, which is described below. The body port of the transistor N1 can be coupled to a ground node VSS, which is described below. The transistor N1 can include a substrate SUB1. The body port of the transistor N1 can be coupled (directly) to the substrate SUB1. The substrate SUB1can be coupled (directly) to the ground node VSS. The ESD protection circuit includes a transistor N2 coupled to the transistor N1. The transistor N2 may be a similar type of transistor as the transistor N1. In some embodiments, the transistor N2 may be rated for a first voltage and other circuits coupled to the pad P1may be rated for a second voltage that is higher than the first voltage. In other words, an operation voltage of the transistor N2 may be lower than an operational voltage for the pad P1. In some embodiments, a ratio of an operation voltage of the transistor N2 and an operation voltage of the pad P1is 0.85, less than 0.85, 0.7, less than 0.7, 0.5, less than 0.5, or any other value or range between 0 and 1. In some embodiments, the transistor N2 is rated for 1.2V (e.g., N2 is a process specified 1.2V device) and the pad P1is rated for 1.8V. The transistor N2 and the pad P1can be rated for any other voltage values or ranges without departing from the scope of the present disclosure. The drain port of the transistor N2 can be coupled to the transistor N1. The source port of the transistor N2 can be coupled to the ground node VSS. The gate port of the transistor N2 can be coupled to the ground node VSS. In some embodiments, the gate port of the transistor N2 is coupled to a tie-low cell. The source port of the transistor N2 and the body port of the transistor N2 can be coupled to the ground node VSS. The transistor N2 can include the substrate SUB1. In other words, the transistor N2 can share the substrate SUB1with the transistor N1. The body port of the transistor N2 can be coupled (directly) to the substrate SUB1. The transistors N1 and N2 may be designed, configured, and operated to protect the ESD-sensitive circuit during an ESD event. In some embodiments, when an ESD pulse is applied to the pad P1, a parasitic negative-positive-negative (NPN) bipolar transistor NPN1 in the substrate SUB1of the transistors N1 and N2 is turned on, creating a discharge path in the substrate SUB1for the ESD pulse. The ESD pulse can be referred to as an ESD signal. The parasitic transistor NPN1 can be turned on when a substrate current (Isub) flows through a well resistance (Rb) to generate a voltage greater than a threshold at a node where NPN1 couples to Rb. The parasitic transistor NPN1 can be referred to as embedded in the transistors N1 and N2 or embedded in the substrate of the transistors N1 and N2. Although NPN1 is an NPN bipolar transistor, the ESD protection circuit100can include a positive-negative-positive (PNP) bipolar transistor while remaining in the scope of the present disclosure. The resulting ESD voltage potential across the pad P1and another terminal (such as a VSS node) can be lower than without the transistors N1 and N2. In some embodiments, the transistors N1 and N2 are a stack of two transistors. In some embodiments, the transistor N1 is a cascode transistor and the transistor N2 is a common source transistor. Although N1 and N2 are a stack of two transistors, N1 and N2 can be a part of a stack of more than two transistors without departing from the scope of the present disclosure. The ESD protection circuit100includes a circuit CKTA coupled on one end to a gate of N1 and on the other end to a node VDD. The VDD node may be referred to as a power rail node or power rail terminal. The node VDD may be (e.g., selectively) coupled to a power rail (e.g., power supply) that provides a supply voltage to the node VDD. The CKTA may be designed, configured, and operated to protect the transistor N1 during a pad-to-power ESD event. A pad-to-power ESD event can be defined as an ESD pulse being applied to the pad P1and causing a discharge path from the pad P1to the node VDD. In some embodiments, during a pad-to-power ESD event, the node VDD is connected to the power rail, ground rail, or any low-impedance source. In some embodiments, during a pad-to-power ESD event, other terminals, such as the node VSS, are floating. The ESD protection circuit100includes a circuit CKTB coupled on one end to the node VDD and on the other end to a node VSS. The node VSS may be referred to as a ground rail node or a ground rail terminal. The node VSS may be (e.g., selectively) coupled to a ground rail that supplies a ground voltage to the node VSS. The CKTB may be designed, configured, and operated to protect the ESD-sensitive circuit during a pad-to-ground ESD event. A pad-to-ground ESD event can be defined as an ESD pulse being applied to the pad P1and causing a discharge path from the pad P1to the node VSS. In some embodiments, during a pad-to-ground ESD event, the node VSS is connected to the ground rail, power rail, or any low-impedance source. In some embodiments, during a pad-to-ground ESD event, other terminals, such as the node VDD, are floating. Disclosed herein is operation of the ESD protection circuit100during a pad-to-power ESD event. In some embodiments, an ESD pulse is applied at the pad P1. In some embodiments, the VSS node is coupled to a ground rail. A voltage at the pad P1may rise. In some embodiments, the VDD node is floating. In some embodiments, the gate voltage of N1 tracks the pad voltage of P1. That is, a voltage of the gate of N1 may maintain a fixed voltage offset from a voltage of the pad P1. Thus, the voltage at the gate of N1 rises. In some embodiments, after the gate of N1 reaches a first voltage level, the circuit CKTA is enabled. In some embodiments, a current from the ESD pulse discharges through CKTA to the VDD node. Discharging a current can be referred to as sinking a current. In some embodiments, after CKTA is enabled, the gate voltage of N1 tracks the VDD node voltage. That is, a voltage of the gate of N1 may maintain a fixed voltage offset from a voltage of the VDD node. In some embodiments, a parasitic transistor NPN1 in the substrate SUB1of the transistors N1 and N2 turns on and discharges current from the ESD pulse. In some embodiments, because the gate voltage of N1 tracks the VDD node voltage, the parasitic transistor NPN1 in the substrate SUB1of the transistors N1 and N2 can discharge more current than when the gate voltage of N1 tracks the pad voltage of P1. This may be because a voltage of the gate of N1 is lower when the gate voltage of N1 tracks the VDD node voltage. The lower voltage of the gate of N1 can cause a greater voltage difference between the drain of N1 and the gate of N1, which can induce a greater substrate current Isub through gate-induced drain leakage (GIDL). By discharging more current via the substrate SUB1, the ESD protection circuit100can reduce a voltage across ESD-sensitive circuits coupled between the pad P1and the VDD node. In some embodiments, coupling CKTA between the VDD node and the gate of N1 is advantageous as compared to directly coupling the VDD node to the gate of N1. In some embodiments, CKTA can prevent the gate-source junction or the gate-drain junction of the N1 transistor from exceeding a voltage breakdown level by absorbing some of the voltage difference between the pad P1and the VDD node. Disclosed herein is operation of the ESD protection circuit100during a pad-to-ground ESD event. In some embodiments, an ESD pulse is applied at the pad P1. In some embodiments, the VSS node is coupled to a ground rail. In some embodiments, the VDD node is floating. In some embodiments, the gate voltage of N1 tracks the pad voltage of P1. That is, a voltage of the gate of N1 may maintain a fixed voltage offset from a voltage of the pad P1. In some embodiments, after the gate of N1 reaches a first voltage level, the circuit CKTA is enabled and CKTB are enabled. In some embodiments, current from the ESD pulse discharges through CKTA and CKTB to the VSS node. In some embodiments, after CKTA and CKTB are enabled, the gate voltage of N1 tracks the VSS node voltage. That is, a voltage of the gate of N1 may maintain a fixed voltage offset from a voltage of the VSS node. In some embodiments, a parasitic NPN transistor in the substrate SUB1of the transistors N1 and N2 turns on and discharges current from the ESD pulse. In some embodiments, because the gate voltage of N1 tracks the VSS node voltage, the parasitic NPN transistor in the substrate SUB1of the transistors N1 and N2 can discharge more current than when the gate voltage of N1 tracks the pad voltage of P1. This may be because a voltage of the gate of N1 is lower when the gate voltage of N1 tracks the VSS node voltage. By discharging more current via the substrate SUB1, the ESD protection circuit100can reduce a voltage across ESD-sensitive circuits coupled between the pad P1and the VSS node. FIG.2illustrates an ESD protection circuit200, in accordance with some embodiments of the present disclosure. In some embodiments, the ESD protection circuit200is an implementation of the ESD protection circuit100ofFIG.1. In some embodiments, CKTA ofFIG.1includes a stack of transistors201. In some embodiments, the stack of transistors201includes transistors N3, N4, and N5, although the stack of transistors201can include greater than or less than three transistors while remaining the scope of the present disclosure. In some embodiments, a drain of the transistor N3 is coupled to the gate of the N1 transistor. In some embodiments, a source of the transistor N3 is coupled to a drain of the transistor N4 and a source of the transistor N4 is coupled to a drain of the transistor N5. In some embodiments, a gate of each of the transistors N3, N4, and N5 are (directly) coupled to the VSS node. In some embodiments, a gate of each of the transistors N3, N4, and N5 are coupled to the VSS node via a respective tie-low cell. In some embodiments, CKTB ofFIG.1includes an ESD clamp202. In some embodiments, the ESD clamp202includes a transistor N6. In some embodiments, a drain of the transistor N6 is coupled to a source of the transistor N5. In some embodiments, a source of the transistor N6 is coupled to the VSS node. In some embodiments, the gate of the transistor N6 is floating. In some embodiments, the gate of the transistor N6 is coupled to the drain of the transistor N6 by a parasitic capacitance. FIG.3illustrates an ESD protection circuit300, in accordance with some embodiments of the present disclosure. The ESD protection circuit300similar to the ESD protection circuit200ofFIG.2except that the ESD clamp302of the ESD protection circuit200includes a capacitor C and a resistor R. Advantageously, the ESD clamp302can selectively turn on based on a resistor-capacitor (RC) time constant associated with the capacitor C and the resistor R. Thus, the ESD clamp302can turn on for a pad-to-ground ESD event but not for non-ESD operation. In some embodiments, the capacitor C and the resistor R are discrete components. In some embodiments, the capacitor C and the resistor R are external to the transistor N6. In other words, in some embodiments, the capacitor C and the resistor R are not a parasitic C and a parasitic R, respectively. In some embodiments, the capacitor C is coupled between the gate of the transistor N6 and the drain of the transistor N6. In some embodiments, the resistor R is coupled between the gate of the transistor N6 and the source of the transistor N6. In some embodiments, the RC time constant of the ESD clamp302is less than an RC time constant of a non-ESD event and greater than an RC time constant of an ESD event such as the pad-to-ground ESD event. In other words, in some embodiments, the RC time constant of the ESD clamp302is less than an RC time constant of a signal associated with a non-ESD event and greater than an RC time constant of a signal associated with an ESD event such as the pad-to-ground ESD event. In some embodiments, the ESD clamp302is enabled when the gate of the transistor N6 receives a signal having an RC time constant that is less than the RC time constant of the ESD clamp302. In some embodiments, the ESD clamp302is remains disabled when the gate of the transistor N6 receives a signal having an RC time constant that is greater than the RC time constant of the ESD clamp302. Although the ESD clamp302is shown as having an RC time constant that can turn on for a pad-to-ground ESD event but not for non-ESD operation, the ESD clamp202ofFIG.2can also have an RC time constant that can turn on for a pad-to-ground ESD event but not for non-ESD operation based on parasitic capacitances and resistances of the ESD clamp202. FIG.4illustrates an ESD protection circuit400, in accordance with some embodiments of the present disclosure. The ESD protection circuit400is similar to the ESD protection circuit100except that the ESD protection circuit100includes switches SWA and SWB at the gates of N1 and N2, respectively. Advantageously, the switches SWA and SWB of the ESD protection circuit400can allow the gates of N1 and N2 to float during a pad-to-ground ESD event, which can further protect ESD-sensitive circuits during such an event. In some embodiments, the switches SWA and SWB can selectively turn off based on a resistor-capacitor (RC) time constant associated with parasitic resistors and parasitic capacitors in the switches SWA and SWB. In some embodiments, the RC time constant of the switches SWA and SWB is less than an RC time constant of a non-ESD event and greater than an RC time constant of an ESD event such as the pad-to-ground ESD event. In other words, in some embodiments, the RC time constant of the switches SWA and SWB is less than an RC time constant of a signal associated with a non-ESD event and greater than an RC time constant of a signal associated with an ESD event such as the pad-to-ground ESD event. In some embodiments, the switches SWA and SWB are disabled when the gate of the transistor N1 and the gate of the transistor N2 receive a signal, such as a signal of an ESD event, having an RC time constant that is less than the RC time constant of the switches SWA and SWB. In some embodiments, the switches SWA and SWB are enabled when the gate of the transistor N1 and the gate of the transistor N2 receive a signal, such as a signal during non-ESD operation, having an RC time constant that is greater than the RC time constant of the switches SWA and SWB. Disclosed herein is operation of the ESD protection circuit100during a pad-to-ground ESD event. In some embodiments, an ESD pulse is applied at the pad P1. In some embodiments, the VSS node is coupled to a ground rail. In some embodiments, the RC time constant of the ESD pulse is lower than the time constant of the switches SWA and SWB. In some embodiments, the gate of the transistor N1 and gate of the transistor N2 receive the ESD pulse. In some embodiments, the switches SWA and SWB are disabled based on the gate of the transistor N1 and gate of the transistor N2 receiving the ESD pulse. In some embodiments, as a result of disabling the switches SWA and SWB, the gate voltage of the transistor N1 and gate voltage of the transistor N2 track the pad voltage of P1. That is, a voltage of the gate of N1 may maintain a first fixed voltage offset from a voltage of the pad P1and voltage of the gate of N2 may maintain a second fixed voltage offset from a voltage of the pad P1. The gate voltage of N1 and the gate voltage of N2 can track the pad voltage of P1because of coupling via parasitic capacitors C1and C2, respectively. The parasitic capacitor C1can be coupled between the gate of N1 and the pad P1, and the parasitic capacitor C2can be coupled between the gate of N2 and the pad P1. In some embodiments, a parasitic NPN transistor in the substrate SUB1of the transistors N1 and N2 turns on and discharges current from the ESD pulse. In some embodiments, because both the gate of the transistor N1 and the gate of transistor N2 track the pad P1, the parasitic NPN transistor in the substrate SUB1of the transistors N1 and N2 can discharge more current than when only the gate voltage of N1 tracks the pad voltage of P1. This may be due to a channel current through N1 and N2, which can cause ionization, which can induce the substrate current Isub. By discharging more current via the substrate SUB1, the ESD protection circuit100can reduce a voltage across ESD-sensitive circuits coupled between the pad P1and the VSS node. FIG.5illustrates an ESD protection circuit500, in accordance with some embodiments of the present disclosure. In some embodiments, the ESD protection circuit500is an implementation of the ESD protection circuit400ofFIG.4. In some embodiments, the switch SWA includes a transistor N7. In some embodiments, the switch SWB includes a transistor N8. The transistors N7 and N8 can be NMOS or PMOS transistors. In some embodiments, the circuit CKTC ofFIG.4includes a stack of transistors501. The stack of transistors501may be similar to the stack of transistors201ofFIG.2. The stack of transistors501can be coupled on one end to the switch SWA and on the other end to the VDD node. In some embodiments, the circuit CKTD ofFIG.4includes a tie-low cell502. The tie-low cell502can include a transistor N9. A drain of the transistor N9 can be coupled to the switch SWB. A source of the transistor N9 can be coupled to the VSS node. A gate of the transistor N9 can be coupled to the VDD node. In some embodiments, the gate of the transistor N9 is directly coupled to the VDD node. In some embodiments, the gate of the transistor N9 is coupled to the VDD node via another transistor. In some embodiments, the transistor N9 is an NMOS transistor. In some embodiments, the other transistor is a diode connected PMOS transistor. FIG.6illustrates a flowchart of a method600to operate the ESD protection circuit100, in accordance with some embodiments of the present disclosure. It is noted that the method600is merely an example and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the method600ofFIG.6, and that some other operations may only be briefly described herein. In some embodiments, the method600is performed by the ESD protection circuit100. At operation610, in some embodiments, an ESD protection circuit (e.g., the ESD protection circuit100ofFIG.1, the ESD protection circuit200ofFIG.2, or the ESD protection circuit300ofFIG.3) receives, at a pad (e.g., pad P1ofFIG.1) coupled to a first transistor (e.g., the transistor N1), an ESD voltage. In some embodiments, the gate voltage of the first transistor tracks the pad voltage. In some embodiments, the first transistor is coupled to a second transistor. In some embodiments, the first and second transistor are a stack of two transistors. In some embodiments, the first transistor is a cascode transistor and the second transistor is a common source transistor. At operation620, in some embodiments, the ESD protection circuit enables a stack of transistors (e.g., the stack of transistors201ofFIG.2) coupled to the first transistor and an ESD clamp (e.g., the ESD clamp202ofFIG.2, the ESD clamp302ofFIG.3) coupled to the stack of transistors. In some embodiments, the stack of transistors are enabled because a voltage at each source of the stack of transistors increases at least until a voltage difference between each source and a corresponding gate in each transistor (e.g., transistors N3, N4, and N5 inFIG.2) of the stack of transistors exceeds a threshold voltage to turn on the corresponding transistor in the stack of transistors. In some embodiments, the ESD clamp is enabled because the gate and drain of the transistor (e.g., the transistor N6 ofFIG.2) increases until a voltage difference between the gate and the source of the transistor in the ESD clamp exceeds a threshold voltage to turn on the transistor in the ESD clamp. At operation630, in some embodiments, the ESD protection circuit discharges a first current associated with the ESD voltage through the stack of transistors and ESD clamp. In some embodiments, the ESD protection circuit causes a gate of the first transistor voltage to track ground voltage (e.g., the voltage of the VSS node ofFIG.1) that is coupled to the ESD clamp. At operation640, in some embodiments, the ESD protection circuit induces a second current (e.g., Isub ofFIG.1) through a substrate (e.g., SUB1ofFIG.1) of the first transistor and a second transistor coupled to the first transistor. In some embodiments, the ESD protection circuit induces the second current via gate induced drain-to-substrate leakage. FIG.7illustrates a flowchart of a method700to operate the ESD protection circuit400, in accordance with some embodiments of the present disclosure. It is noted that the method700is merely an example and is not intended to limit the present disclosure. Accordingly, it is understood that additional operations may be provided before, during, and after the method700ofFIG.7, and that some other operations may only be briefly described herein. In some embodiments, the method700is performed by the ESD protection circuit400. At operation710, in some embodiments, an ESD protection circuit (e.g., the ESD protection circuit400ofFIG.4or the ESD protection circuit500ofFIG.5) receives, at a pad (e.g., pad P1ofFIG.4) coupled to a first transistor (e.g., the transistor N1 ofFIG.4), an ESD voltage. In some embodiments, the first transistor is coupled to a second transistor (e.g., the transistor N2 ofFIG.4). In some embodiments, the first and second transistor are a stack of two transistors. In some embodiments, the first transistor is a cascode transistor and the second transistor is a common source transistor. At operation720, in some embodiments, the ESD protection circuit disables a first switch (e.g., the switch SWA ofFIG.4) coupled to a gate of the first transistor and a second switch (e.g., the switch SWB ofFIG.4) coupled to a gate of the second transistor. In some embodiments, the first switch is disabled because a voltage at the source of the first switch increases at least until a voltage difference between a gate of the first switch and a source of the first switch goes below a threshold voltage. In some embodiments, the second switch is disabled because a voltage at the source of the second switch increases at least until a voltage difference between a gate of the second switch and a source of the second switch goes below a threshold voltage. At operation730, in some embodiments, the ESD protection circuit discharges a first current associated with the ESD voltage through the first transistor and the second transistor. In some embodiments, the ESD protection circuit causes a gate voltage of the first transistor and a gate voltage of the second transistor to track the pad voltage. At operation740, in some embodiments, the ESD protection circuit induces a second current (e.g., Isub ofFIG.1) through a substrate (e.g., SUB1ofFIG.1) of the first transistor and a second transistor coupled to the first transistor. In some embodiments, the ESD protection circuit induces the second current via ionization caused by the first current. FIG.8illustrates a performance comparison plot800, in accordance with some embodiments of the present disclosure. The comparison plot800shows a current-voltage (IV) curve for two different embodiments during an ESD event. The plotted voltage represents the voltage across the pad and the ground. The embodiment plotted on the left is the embodiment ofFIG.1, in which N1 gate tracks VSS. The embodiment plotted on the right is an embodiment that lacks the improvements disclosed herein, which is referred to as “other embodiment,” in which N1 gate tracks the pad (without improvements of the embodiment ofFIG.4). The embodiment ofFIG.1shows a maximum voltage 4.8V and the other embodiment shows a maximum voltage of 6.4V. Thus, the embodiment ofFIG.1improves the voltage across the pad and the ground by 1.6V. The maximum voltage is referred to as “Vt1” in the plot800. In some aspects of the present disclosure, an electrostatic discharge (ESD) protection circuit is disclosed. In some aspects, the ESD protection circuit includes a first transistor coupled to a pad, a second transistor coupled between the first transistor and ground, a stack of transistors coupled to the first transistor, and an ESD clamp coupled between the stack of transistors and the ground. In some embodiments, the ESD clamp has a resistor-capacitor (RC) time constant that is less than an RC time constant of a non-ESD event and greater than an RC time constant of an ESD event. In some embodiments, a ratio of an operation voltage of each of the first and second transistors and an operation voltage of the pad is less than 0.85. In some embodiments, a gate of the second transistor is coupled to the ground. In some embodiments, a gate of the second transistor is coupled to a tie-low circuit. In some embodiments, the stack of transistors includes a third transistor, a fourth transistor, and a fifth transistor, wherein a source of the third transistor is coupled to a drain of the fourth transistor, and wherein a source of the fourth transistor is coupled to a drain of the fifth transistor. In some embodiments, a drain of the stack of transistors is coupled to a gate of the first transistor and a source of the stack of transistors is coupled to the ESD clamp. In some embodiments, each gate of the stack of transistors is coupled to the ground. In some embodiments, the ESD clamp includes a third transistor, wherein a drain of the third transistor is coupled to the stack of transistors and the source of the third transistor is coupled to the ground. In some embodiments, the ESD clamp includes a capacitor coupled between a gate of the third transistor and the drain of the third transistor, and a resistor coupled between the gate of the third transistor and the source of the third transistor. In some embodiments, a node between the stack of transistors and the ESD clamp is coupled to a voltage supply during non-ESD operation and is floating during a pad-to-ground ESD event. In some aspects of the present disclosure, an electrostatic discharge (ESD) protection circuit is disclosed. In some aspects, the ESD protection circuit includes a first transistor coupled to a pad, a second transistor coupled between the first transistor and ground, a first switch coupled to a gate of the first transistor, and a second switch coupled to a gate of the second transistor. In some embodiments, the first switch and the second switch have a resistor-capacitor (RC) time constant that is less than an RC time constant of a non-ESD event and greater than an RC time constant of an ESD event. In some embodiments, the ESD protection circuit further includes a first parasitic capacitance coupled between the gate of the first transistor and the pad, and a second parasitic capacitance coupled between the gate of the second transistor and the pad. In some embodiments, each of the first switch and the second switch is an N-type metal-oxide-semiconductor (NMOS) transistor. In some embodiments, the ESD protection circuit further includes a stack of transistors and an ESD clamp coupled between the first switch and the ground. In some embodiments, the ESD protection circuit further includes a tie-low cell coupled between the second switch and the ground. In some embodiments, the tie-low cell comprises a third transistor, a drain of the third transistor coupled to the second switch, a source of the third transistor coupled to the ground, and a gate of the third transistor coupled to a power rail. In some aspects of the present disclosure, a method for operating an electrostatic discharge (ESD) protection circuit is disclosed. In some aspects, the method includes receiving, at a pad coupled to a first transistor, an ESD voltage, enabling a stack of transistors coupled to the first transistor and an ESD clamp coupled to the stack of transistors, discharging a first current associated with the ESD voltage through the stack of transistors and ESD clamp, and inducing a second current through a substrate of the first transistor and a second transistor coupled to the first transistor. In some embodiments, the method further includes causing a voltage of a gate of the first transistor to track a voltage of a ground. In some embodiments, the ground is coupled to the ESD clamp. The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. | 36,940 |
11862969 | DETAILED DESCRIPTION OF THE EMBODIMENTS In order to facilitate a further understanding of the content, features and effects of the present disclosure, the present disclosure is described in detail below in conjunction with the embodiments and accompanying drawings. As shown inFIGS.1to8, an hybrid energy storage optimal configuration method for a grid-connected wind storage power generation system is provided. According to the present disclosure, a frequency domain decomposition is performed on a historical wind power output, to count a high-frequency component and a low-frequency component of the historical wind power output, and a rated power of the hybrid energy storage is determined based on a probability distribution function; a hybrid energy storage capacity optimization model for a full life cycle of a wind farm is established to minimize a net present value (NPV) of an annual cost and maximize a target satisfaction rate (TSR); a daily typical scenario for the wind power output is extracted based on a clustering algorithm, to count a time proportion of each typical scenario as an input scenario of the hybrid energy storage capacity optimization model for the full life cycle of the wind farm; and the hybrid energy storage capacity optimization model for the full life cycle of the wind farm is solved with a multi-objective optimization algorithm, to obtain an optimal hybrid energy storage capacity configuration scheme for the grid-connected wind storage power generation system. The fluctuation smoothing effect of an optimized target power curve of wind power may be evaluated, parameters in the optimization algorithm may be adjusted according to the evaluation result, and the hybrid energy storage capacity optimization model for the full life cycle of the wind farm may be further solved and optimized. In an embodiment, the frequency domain decomposition on the wind power output may include a wavelet decomposition, a Kalman filtering and/or an empirical mode decomposition (EMD). The wavelet decomposition, the Kalman filtering and the EMD may be corresponding algorithms in the conventional art. In an embodiment, the clustering algorithm may include a K-means clustering method, a hierarchical clustering method and/or a Gaussian mixture model method. The K-means clustering method, the hierarchical clustering method and the Gaussian mixture model method algorithm may be corresponding algorithms in the conventional art. The hybrid energy storage capacity optimization model for the full life cycle of the wind farm includes objective functions, decision variables and constraints. Wherein, the decision variables are energy storage capacities, which may be divided into a power-type energy storage capacity and an energy-type energy storage capacity, i.e., Ck(k=1, 2), in MWh. In an embodiment, an objective function F1is established to minimize the NPV of the annual cost: F1=minimize∑k=12(CIk+∑t=1NkCRk(1+r-I)nk,t), where Nk=[∑j=1JSj,k·pj·L·365dk·Ck·cyk]-1;CRk=α·βn·CIk=α·βn·Ak·Ck; where, CIkis an initial cost of a k-th energy storage device, in CNY; CRkis a replacement cost of the k-th energy storage device, in CNY; Nkis a replacement time of the k-th energy storage device, in hours; r is a discount rate for converting a future fund into a present value; I is an inflation rate; nk,tis a period for a k-th replacement of the energy storage device, in years; a is a ratio of the replacement cost to the initial cost; pn is a cost reduction coefficient of an energy storage material in an n-th year; Sj,kis a stored electric quantity of the k-th energy storage device in a j-th typical scenario, in MWh; pjis a time proportion of the j-th typical scenario; L is an operational lifespan of the wind farm, in years; dkis a discharge depth of the k-th energy storage device; Ckis a capacity of the k-th energy storage device, in MWh; cykis a cycle number of the energy storage device; Akis a unit system cost of the k-th energy storage device, in CNY/MWh. In an embodiment, an objective function F2is established to maximize the TSR of the output: F2=maximize∑j=1Jpj·TSRj, where TSRj=∑i=1Tωi,jT;ωi,j={1Pi,j=Pi,j_0Pi,j≠Pi,j_; where, TSRjis a TSR of a hybrid energy storage system (HESS) in the j-th typical scenario; T is a total running period, in min; ωi,jis a determination coefficient for determining whether a system power output is equal to a target power at an i-th minute of the j-th typical scenario; Pi,jis the system power output at the i-th minute of the j-th typical scenario;Pi,jis the target power at the i-th minute of the j-th typical scenario; J is a total number of the typical scenarios; P, is a time proportion of the j-th typical scenario. In an embodiment, the hybrid energy storage capacity optimization model for the full life cycle of the wind farm has constraints, including: an energy storage charge and discharge power constraint: {Pc,min<Pc,t<Pc,maxPd,min<Pd,t<Pd,max; a power balance constraint: SOCt={SOCt-1+ηcPc,tΔt/SWhSOCt-1-Pd,tΔt/(SWhηd); and an energy storage state of charge (SOC) constraint: SOCmin≤SOCt≤SOCmax. Wherein, all the variables above have non-negative values. Where, Pc,tis an energy storage charge power at time t, in MW; Pd,tis an energy storage discharge power at time t, in MW; Pc,minis a lower limit of the energy storage charge power, in MW; Pd,minis a lower limit of the energy storage discharge power, in MW; Pc,ax is an upper limit of the energy storage charge power, in MW; Pd,maxis an upper limit of the energy storage discharge power, in MW; ηcis an energy storage charge efficiency; ηdis an energy storage discharge efficiency; Δt is a control interval, in min; SWhis a rated capacity of the energy storage, in MW; SOCtis an energy storage at time t; SOCt-1is an energy storage at time t−1; SOCminis a lower limit of the energy storage; SOCmaxis an upper limit of the energy storage. In an embodiment, PRRΔtis set as a smoothing index for a target power curve of wind power; PRRΔtis used to evaluate a fluctuation smoothing effect of the target power curve of the wind power, and PRRΔtis calculated as follows: PRRΔt=Pmax,Δt-Pmin,ΔtPR×100%; where, Pmax,Δtis a maximum wind power output during Δt, in MW; Pmin,Δtis a minimum wind power output during Δt, in MW; PRis a rated power of the wind storage power generation system. In an embodiment, the multi-objective optimization algorithm may include a dynamic programming algorithm or a heuristic algorithm. The dynamic programming algorithm and the heuristic algorithm may be corresponding algorithms in the conventional art. In an embodiment, the heuristic algorithm may include a genetic algorithm (GA), an artificial neural network (ANN) and an ant colony algorithm (ACA). The GA, the ANN and the ACA may be corresponding algorithms in the conventional art. The working principle and workflow of the present disclosure are described below with reference to a preferred embodiment of the present disclosure. This embodiment demonstrates a wind storage power generation system with a total installed capacity of 99 MW and an operating period of 20 years. The energy storage of the wind storage power generation system may include power-type energy storage (type I) and energy-type energy storage (type II), which are divided according to the characteristics of energy storage materials, such as an energy storage discharge rate, an energy density and a power density. According to the flowchart inFIG.1, the method specifically includes the following steps 1-5. Step 1: the wind power output is decomposed with the wavelet decomposition signal processing method based on frequencies and amplitudes of wind power fluctuations; the wind power output data for 1-minute level is decomposed into the high- and low-frequency fluctuation components for the hybrid energy storage for smoothing, in order to obtain a target power curve of the wind storage power generation system that meets a grid-connected requirement, as shown inFIG.2. Step 2: probability distribution functions of the high- and low-frequency fluctuation components of the historical wind power output are calculated, as shown inFIG.3andFIG.4; then cumulative distribution functions of the high- and low-frequency fluctuation components are calculated, and rated powers of the energy-type energy storage and the power-type energy storage are reasonably determined based on a confidence coefficient, as shown inFIG.5andFIG.6. In this embodiment, the rated power of the power-type energy storage is 0.5 MW and the rated power of the energy-type energy storage is 10 MW. Step 3: according to historical operating data of the wind storage power generation system, the power output processes for 1-minute level for four typical scenarios in each season are obtained with the k-means clustering algorithm, as shown inFIG.7; the time proportions of the typical wind power scenarios in each season are calculated as the time proportions of the typical scenarios in each season of a planning year of the wind storage power generation system, as shown in Table 1 below. TABLE 1Proportions of days of each typical scenarioin each seasonTypical scenarioSeasonabcdSpring6.44%8.9%7.95%1.92%Summer4.11%9.32%10.14%1.64%Autumn5.75%5.48%13.29%0.41%Winter8.63%5.34%10.41%0.27% Step 4: it is assumed that the wind storage power generation system runs for 20 years, considering factors such as a establishment cost and an power output stability, the hybrid energy storage capacity optimization model for the full life cycle of the wind farm is established to minimize the NPV of the annual cost and maximize the TSR of the output, where the hybrid energy storage capacity optimization model for the full life cycle of the wind farm includes the objective functions, the decision variables and the constraints. Specifically, a. Objective Functions Objective function F1to minimize the NPV of the total cost in the full life cycle of the hybrid energy storage. Specifically, F1=minimize∑k=12(CIk+∑t=1NkCRk(1+r-I)nk,t)(1) where Nk=[∑j=1JSj,k,·pj·L·365dk·Ck·cyk]-1(2)CRk=α·βn·CIk=α·βn·Ak·Ck(3) where, CIkis an initial cost of a k-th energy storage device, in CNY; CRkis a replacement cost of the k-th energy storage device, in CNY; Nkis a replacement time of the k-th energy storage device, in hours; r is a discount rate for converting a future fund into a present value; I is an inflation rate; nk,tis a period for a k-th replacement of the energy storage device, in years; a is a ratio of the replacement cost to the initial cost; βnis a cost reduction coefficient of an energy storage material in an n-th year; Sj,kis a stored electric quantity of the k-th energy storage device in a j-th typical scenario, in MWh; pjis a time proportion of the j-th typical scenario; L is an operational lifespan of the wind farm, in years; dkis a discharge depth of the k-th energy storage device; Ckis a capacity of the k-th energy storage device, in MWh; cykis a cycle number of the energy storage device; Akis a unit system cost of the k-th energy storage device, in CNY/MWh. Objective function F2: to maximize the TSR of the power output of the system. Specifically, F2=maximize∑j=1Jpj·TSRj(4)TSRj=∑i=1Tωi,jT(5)ωi,j={1Pi,j=Pi,j_0Pi,j≠Pi,j_(6) where, TSRjis a TSR of a hybrid energy storage system (HESS) in the j-th typical scenario; T is a total running period, in min; ωi,jis a determination coefficient for determining whether a system power output is equal to a target power at an i-th minute of the j-th typical scenario; Pi,jis the system power output at the i-th minute of the j-th typical scenario;Pi,jis the target power at the i-th minute of the j-th typical scenario; J is a total number of the typical scenarios; pjis a time proportion of the j-th typical scenario. b. Decision Variables The decision variables are energy storage capacities Ck, in MWh. There are two types of energy storage devices, the power-type energy storage device and the energy-type energy storage device. The decision variables may be divided into the power-type energy storage capacity and the energy-type energy storage capacity. c. Constraints(1) the energy storage charge and discharge power constraint: {Pc,min<Pc,t<Pc,maxPd,min<Pd,t<Pd,max(7)(2) the power balance constraint: SOCf={SOCt-1+ηcPc,tΔt/SWhSOCt-1-Pd,tΔt/(SWhηd)(8)(3) the energy storage SOC constraint: SOCmin≤SOCt≤SOCmax(9)(4) a non-negative constraint: all the variables above have non-negative values. where, Pc,tis an energy storage charge power at time t, in MW; Pd,tis an energy storage discharge power at time t, in MW; Pc,minis a lower limit of the energy storage charge power, in MW; Pd,minis a lower limit of the energy storage discharge power, in MW; Pc,maxis an upper limit of the energy storage charge power, in MW; Pd,maxis an upper limit of the energy storage discharge power, in MW; ηcis an energy storage charge efficiency; ηdis an energy storage discharge efficiency; Δt is a control interval, in min; SWhis a rated capacity of the energy storage, in MW; SOCtis an energy storage at time t; SOCt-1is an energy storage at time t−1; SOCminis a lower limit of the energy storage; SOCmaxis an upper limit of the energy storage. Step 5: the hybrid energy storage capacity configuration of the wind storage power generation system are solved with the multi-objective optimization algorithm, as shown in Table 3. The optimal configuration includes super capacitors (SCs) of 500 kW/93 kWh and vanadium redox flow batteries (VRBs) of 10 MW/7.53 MWh. The target power curves of wind power and high- and low-frequency power fluctuation curves obtained in Step 1, the rated powers of the hybrid energy storage obtained in Step 2, the time proportion of each typical scenario determined in Step 3, and the characteristic parameters of the energy storage materials in Table 2 are taken as inputs, and the optimization results of the wind power output in the typical scenarios are taken as outputs. Then the power output curves of the wind storage power generation system before and after optimization are shown inFIG.8. TABLE 2Characteristic parameters of energy storage materialsFlywheelLithium-ionEnergy storageenergybatteryparametersSCstorageVRB(Li-ion)System cost12000650035002300(in CNY/kWh)Number of cycles10000020 years160005000Conversion efficiency95%85%80%95%Discharge depth100%100%90%95% TABLE 3Optimal hybrid energy storage capacity configurationscheme for the wind storage power generation systemSC +Flywheel energySC +Optimized resultsVRBstorage + VRBLi-ionType I energy storage93313.293capacity (in kWh)Type II energy storage7.537.536.15capacity (in kWh)Objective 1: NPV2747.12839.082776.0(in 10,000 CNY)Objective 2: TSR91.47%91.28%93.26%Replacement times of000type I energy storageReplacement times of003type II energy storage PRRΔtis set as the smoothing index of the target power curve of wind power; PRRΔtis used to evaluate the fluctuation smoothing effect of the power curve of wind power, and PRRΔtis calculated as follows: PRRΔt=Pmax,Δt-Pmin,ΔtPR×100%(10) where, Pmax,Δtis the maximum wind power output during Δt, in MW; Pmin,Δtis the minimum wind power output during Δt, in MW; PRis a rated power of the wind storage power generation system. A lower PRR indicates a better smoothing effect. In this embodiment, Δt was 1 minute and 10 minutes, respectively. The fluctuation amplitude reduction effect of the wind storage power generation system is obvious (see Table 4), and the number of wind power output fluctuations is decreased by 71.25%. Therefore, after the optimization, the amplitude and frequency of the grid-connected power generation system are reduced, and the stability of the grid-connected power supply is improved. TABLE 4Fluctuation effect of the wind storage powergeneration system after optimizationFluctuationIndexamplitude reductionPRR1 minPRR1 0minMaximum fluctuation−74.43%−70.40%Average fluctuation−33.49%−25.24% In order to verify the superiority of the hybrid energy storage solution over a single energy storage solution, the single energy storage solution adopts the VRB for comparison. The results show that, due to the frequent charge and discharge of the single storage battery, the lifespan of the VRB quickly drops to 7.1 years, which is far less than its design life. In addition, the replacement cost of the VRB increases, and the NPV of the total cost increases by 1.046 million. The participation of the hybrid energy storage greatly optimizes the working status of the energy storage system and extends its operational lifespan. The above embodiments are only used to illustrate the technical ideas and features of the present disclosure, such that those skilled in the art may understand the content of the present disclosure and implement the present disclosure accordingly. The scope of the present disclosure is not limited by the above embodiments, that is, any equivalent changes or modifications made under the spirit disclosed by the present disclosure still fall within the scope of the present disclosure. | 17,135 |
11862970 | DETAILED DESCRIPTION OF THE EMBODIMENTS Exemplary embodiments will be described in detail herein, and the examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different accompanying drawings denote the same or similar element. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims. Embodiment 1 In the preferred embodiment 1 of the present disclosure, a DC home power consumption system is provided. Specifically,FIG.1shows an optional structural block diagram of the system, as shown inFIG.1, and the system includes:a home power supply102which is configured to supply power for the home power consumption system;a high-voltage DC bus104which is connected to the home power supply102and configured to supply power for a high-power appliance;a low-voltage DC bus106which is connected to the home power supply102or the high-voltage DC bus104and configured to supply power for a low-power appliance. The high-power appliance is optionally an appliance of which power is greater than the first preset power, and the low-power appliance is optionally an appliance of which power is less than the second preset power. In the above embodiments, a full DC home power consumption system is proposed, which greatly reduces the DC home voltage level, and forms a basic DC home wiring principle according to a concept of high and low voltage partitions and DC appliance application partitions, to ensure safety and reliability of using electricity of the DC home appliances. In a preferred embodiment of the present disclosure, the home power supply is a DC grid or a non-DC grid; the non-DC grid includes at least one of the following: an AC power grid, a new energy resource and an energy storage device. When the home power supply is the DC grid, the high-voltage DC bus is directly connected to the DC grid, and the low-voltage DC bus is connected to the high-voltage DC bus. When the home power supply is the non-DC grid, the high-voltage DC bus is connected to the non-DC grid through an energy router, and the low-voltage DC bus is connected to the energy router or the high-voltage DC bus. When the home power supply is the DC grid, the DC home power consumption system, as shown inFIG.2, is a distributed full DC home system, the home DC power supply is a 360V-400V DC power supply provided by the DC grid directly, and the low-voltage DC bus is connect to the high voltage DC bus through a DC convertor. Further, that the low-voltage DC bus is connected to the energy router or the high-voltage DC bus includes: it is determined that the low-voltage DC bus is connected to the energy router or the high-voltage DC bus according to an output capability of the low-voltage DC bus and/or an output line of the energy router. The output capability of the low-voltage DC bus is a transmission capability of the low-voltage DC bus or a transmission distance of the low-voltage DC bus. The output capability of the low-voltage DC bus includes meeting a low-voltage home requirement or not meeting a low-voltage home requirement. The output line of the energy router includes a high-voltage DC line or a high-voltage DC line and a low-voltage DC line. When the output capability of the low-voltage DC bus meets a low-voltage home requirement, and the output line of the energy router includes the high-voltage DC line and the low-voltage DC line, the low-voltage DC bus is connected to the energy router through the low-voltage DC line. As shown inFIG.3, it is a centralized full DC home system, and the home DC power supply may be an AC grid/a new energy plus an energy router, or a DC grid plus an energy router; when the output capability of the low-voltage DC bus does not meet the low-voltage home requirement, or the output line of the energy router is the high-voltage DC line, the low-voltage DC bus is connected to the high-voltage DC bus; the high-voltage DC bus is connected to the high-voltage DC line. Further, the low-voltage DC bus is divided into different low-voltage bus areas according to a use area, and when the low-voltage DC bus is connected to the high-voltage DC bus, each of the low-voltage bus areas is connected to the high-voltage DC bus through a DC converter. As shown inFIG.4, it is a centralized-distributed full DC home system, and the home DC power supply may be an AC grid/a new energy plus an energy router, or a DC grid and an energy router. The low-voltage DC bus is divided into different low-voltage bus areas according to a use area, and when the low-voltage DC bus is connected to the high-voltage DC bus, each of the low-voltage bus areas is connected to the high-voltage DC bus through a DC converter. Further, the high-voltage DC bus is located in an upper part of the home space, and the low-voltage DC bus is located in a lower part of the home space. Voltages of the high-voltage DC bus and the low-voltage DC bus are determined according to an area where the home power system is located. The basic architecture of the three kinds of full DC home power consumption systems adopts a basic thought of high and low voltage safety isolation. The high voltage has a range from 360V to 400V (according to actual application scenarios or national standards); the safe low voltage has a value 48V/24V (according to actual application scenarios or national standard implementation). The basic architecture reduces the multiple DC voltages of the full DC home power consumption system to a high-voltage and a safe low-voltage. At the same time, according to the architecture and daily application habits of an appliance, it is recommended to locate the high-voltage wiring in a upper part of the home space when wiring for the home; it is convenient to use that the safe low-voltage wiring is located in the lower part of the home space; at the same time, the space isolation of high and low voltage is realized to ensure the safety and reliability of the overall home electricity. Embodiment 2 According to the system provided in the above embodiment 1, a preferred embodiment 2 of the present disclosure also provides a wiring method for home appliances. The wiring method may be directly applied to the system described above. Specifically,FIG.5shows an optional flow chart of the method, and as shown inFIG.5, the method includes the following steps S502-S504:Step502: obtaining electricity parameters of each of the home appliances;Step504: connecting the home appliance to a high-voltage DC bus or a low-voltage DC bus according to the electricity parameters of the home appliance. In the above embodiment, a wiring method for home appliances is proposed, which greatly reduces the DC home voltage level, and forms a basic DC home wiring principle according to a concept of high and low voltage partitions and DC appliance application partitions, to solve safety and reliability of using electricity of the DC home appliances. The electricity parameters at least includes: power, a usage frequency, and a user requirement. A priority of the electricity parameters is: a priority of the power>a priority of the usage frequency>a priority of the user requirement; and the connecting home appliance to a high-voltage DC bus or a low-voltage DC bus according to the electricity parameters of the home appliance, includes: connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the priority of the electricity parameters of the home appliance. Preferably, the connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the priority of the electricity parameters of the home appliance, includes: connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the power of the home appliance, including: connecting the home appliance to the high-voltage DC bus when the power of the home appliance is greater than a first preset power; connecting the home appliance to the low-voltage DC bus when the power of the home appliance is less than a second preset power; and connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the usage frequency of the home appliance when the power of the home appliance is less than or equal to the first preset power and greater than or equal to the second preset power. Further, according to the usage frequency of the home appliance, the home appliance is divided into different using areas, and the using areas include at least one of the following: a bedroom area, a living room area, a study area, a dining area, a bathroom area, and a kitchen area, The bedroom area, the living room area, the study area, and the dining area are frequent activity areas; and the bathroom area and the kitchen area are living functional areas. The connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the usage frequency of the home appliance, includes: connecting the home appliance to the low-voltage DC bus when the home appliance is in a frequent activity area; and connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the use requirement of the home appliance, when the home appliance is in a living function area. Preferably, the connecting the home appliance to the high-voltage DC bus or the low-voltage DC bus according to the use requirement of the home appliance, includes: connecting the home appliance to the high-voltage DC bus when the use requirement is to be located in an upper part of a home environment; and connecting the home appliance to the low-voltage DC bus when the use requirement is to be located in a lower part of the home environment. According to the usage area and habits, the home DC appliances are evaluated from the three dimensions of power, voltage, and usage area, and the distribution diagram of the DC appliances in the full DC home application environment is determined as shown inFIG.6. In frequent activities areas, such as, a bedroom area, a living room area, a study area, a dining area and so on, DC appliances are often configured as low-power, safe low-voltage and removable at any time. Additionally, air conditioners involved in frequent activity areas are installed in the upper part of the home environment according to the installation location and electricity requirements, in order to realize isolated from voltage level and physical space and ensure electricity safety. In living function areas, such as a bathing area and a kitchen area, DC appliances usually have a slightly higher power level, high-voltage DC bus or low-voltage DC bus should be selected reasonably according to the electricity requirements, and wiring design should be carried out according to the principle of high and low voltage partition. Embodiment 3 In a preferred embodiment 3 of the present disclosure, a computer device is provided based on the wiring method for the home appliances provided in the above-mentioned embodiment 2, including: a memory, a processor, and a computer program stored in the memory and run on the processor. The processor executes the computer program to implementing the wiring method for home appliances as described above. In the above embodiments, a wiring method for home appliances is proposed, which greatly reduces the DC home voltage level, and forms a basic DC home wiring principle according to a concept of high and low voltage partitions and DC appliance application partitions, to ensure safety and reliability of using electricity of the DC home appliances. Embodiment 4 In a preferred embodiment 4 of the present disclosure, a storage medium containing computer-executable instructions is provided based on the wiring method for the home appliances provided in the above-mentioned embodiment 2, and the computer-executable instructions are configured to perform the wiring method for the home appliances as described above. In the above embodiments, a wiring method for home appliances is proposed, which greatly reduces the DC home voltage level, and forms a basic DC home wiring principle according to a concept of high and low voltage partitions and DC electrical application partitions, to ensure safety and reliability of using electricity of the DC home appliances. Those skilled in the art can easily implement the rest of embodiments of the present disclosure after considering the detailed description and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptive changes of the present disclosure. These variations, uses, or adaptive changes follow the general principles of the present disclosure and include common knowledge or conventional technical skills in the technical field not invented by the present disclosure. The detailed description and embodiments are merely regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims. It should be understood that the present disclosure is not limited to the precise structure that has been described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is merely limited by the accompanying claims. | 13,633 |
11862971 | Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION The electricity that power plants generate is delivered to customers using the electrical grid including over transmission and distribution power lines. High-voltage transmission lines, like those that hang between tall metal towers, carry electricity over long distances to where consumers need it. Higher voltage electricity is more efficient and less expensive for long-distance electricity transmission. The electrical grid has been build for safety and reliability. However, recently there has been an increased concern that the electric grid is vulnerable to cyber attacks. Using grid telemetry to generate a grid telemetry fingerprint can be used to verify that information provided by entities on the electrical grid is actually coming from entities on the electrical grid and not being transmitted from some other location. FIG.1is a diagram of some elements of an electrical grid100. The electrical grid100is an interconnected network for delivering electricity from producers to consumers. Electricity can be produced from centralized power plants102(including, for example, coal plants, nuclear plants, natural gas plants, hydro-electric plants, wind farms, solar arrays, and geothermal plants). Electricity can also be produced by decentralized facilities, such as solar panels116located on a consumers property (such as a roof). Generally, centralized power plants102are located away from consumers. To transfer electricity from the power plants102to the consumers, the electricity is transferred at very high voltages (for example 155,000 volts or more). A step up transformer104increases the voltage of the electricity from the power plant. The high-voltage electricity is distributed over high voltage wires (represented by the tower106). The high voltage electricity can be provided to substations (for example, substations108,114). Generally, a substation steps down the voltage to distribution voltages (for example, less than 10,000 volts). The electricity is then deliverable to consumer areas (for example, consumer areas112, and120). Before it arrives at a consumer, the electricity may be processed by a transformer (such as transformer110) to further reduce the voltage. During the transmission of the electricity, the transmission characteristics can be measured, with substantially similar results, by any device on the same portion of the transmission path, but cannot be measured by devices not on the same portion of the transmission path. For example, any home within the consumer area120can measure these characteristics and each will measure substantially the same value. However, the same characteristics measured within consumer area112will have different values. Similarly, the substation114will measure the same values for the characteristics along the wire126. While substations108and114measure the same values along with connection from the step up transformer104to the substations108and114. Some of these characteristics can include voltages, phase angle differences, reactive power numbers, changes in grid inertia, etc. Voltage refers to the difference in electric potential between two points. Generally, voltage measurements are used to describe the voltage dropped across an electrical device (such as a resistor). The voltage drop across the device can be the difference between measurements at each terminal of the device with respect to a common reference point (or ground). The voltage drop is the difference between the two readings. Phase angle differences is a measure of the difference in phase between two waves (e.g., of the same frequency) and referenced to the same reference (generally, between 0 and 360 degrees or 0 to 2π radians). In some implementations, time is sometimes used (instead of angle) to express position within the cycle of an oscillation. Reactive power numbers is a measurement of the degree to which currents and voltages at the same frequency are out of phase. Reactive power is required to maintain voltage on motors and transformers and is often employed for the electrical grid. Further, switching power supplies in computers and TVs may draw current only during a part of the cycle, thus creating a net reactive load. A change in grid inertia refers to the delay in power generation or the cease of power generation when a power source comes on line or goes off line, respectively. For example, coal plants use heavy turbines to generate electricity. When the plant is brought off line, it can take a considerable amount of time before the turbine stops spinning, and therefore stops generating electricity. Similarly, when the plant is brought offline it can take a substantial amount of time before the plant reaches full power production. Measuring grid inertia can include, for example, using techniques such as those implemented in GRIDMETRIX by REACTIVE TECHNOLOGIES. When the system describes measuring changes in the measurable values (for example, change in grid inertia), changes may be measured over a predetermined period of time, for example, one second, two seconds, 10 seconds, etc. Using these metrics, a grid telemetry fingerprint can be obtained for each section in the electrical grid. A grid telemetry fingerprint is a relatively short piece of data that can, for all practical purposes, uniquely identify a larger set of data. Grid telemetry fingerprints can be used, for example, as a proxy value for the larger data set, as described further below. Generally, any device within the same section of the power grid can generate the same grid telemetry fingerprint at the same time. For example, the grid telemetry fingerprint124, generated between the step up transformer104and the substation114, is the same as the grid telemetry fingerprint130, generated between the step up transformer104and the substation108. However, the grid telemetry fingerprint128, generated between the substation114and the consumers120, is different than either grid telemetry fingerprint124or grid telemetry fingerprint130. It is also useful to note that the values that make up the grid telemetry fingerprint are not constant, but instead, can fluctuate from moment to moment (for example, changes to the grid inertia, phase angle, reactive power, and voltage may change from time to time). Accordingly, the grid telemetry fingerprint for any given section of a grid is changing frequently. In this manner, an attacker could not just sample the grid, or intercept an earlier grid telemetry fingerprint for reuse. Instead, only devices that are on the section of the grid for which the grid telemetry fingerprint is generated can generate the current grid telemetry fingerprint. In some implementations, the grid telemetry fingerprint may be generated in a secure hardware component on a device. For example, the grid telemetry fingerprint may be generated and stored using cryptographically secured hardware such as a dedicated hardware chip, or as a component of another integrated circuit chip. FIG.2illustrates generating a grid telemetry fingerprint from different metrics. A measured voltage202, phase angle204, reactive power206, and grid inertia208(and/or changes in any of the above as measured across a predetermined period of time) can be provided to a grid telemetry fingerprint algorithm210. The grid telemetry fingerprint algorithm210can accept various combinations of different values in order to generate a grid telemetry fingerprint. The grid telemetry fingerprint algorithm210applies functions to the provided values to produce a signature212. For example, in some implementations, the grid telemetry fingerprint algorithm210may apply one or more hash algorithms in order to transform the values provided into a signature. A hash algorithm is a function that can be used to map input data into a fixed size output. In general, a hash algorithm is deterministic, meaning that the same input into a hash algorithm will produce the same output. One feature of many hash algorithms is that once the output is generated the inputs used to generate the hash cannot be derived from the output. This feature makes it more difficult for a potential attacker to spoof the inputs and therefore the grid telemetry fingerprint. In some implementations, the grid telemetry fingerprinting algorithm may preserve the relative values of the inputs so that a comparison within the margin of error may be performed. For example, two grid telemetry fingerprints generated using the grid telemetry fingerprint algorithm may be considered to be the same if the two grid telemetry fingerprint values are within a margin of error of each other. One area in which the grid telemetry fingerprint may be used is in block chain provisioning. FIG.3depicts a schematic of an example blockchain200, according to implementations of the present disclosure. As shown in the figure, a blockchain300may include any number of blocks302, in this example numbered1through N where N is any number. A block302may include, or be associated with a list of transaction(s)304. The transaction(s)304may include the data stored in the blockchain300, and each block302may store any number of records each indicating when and in what order the transaction(s)304are applied to modify the data stored in the blockchain300. Each block302may also include a pointer306that identifies a previous (e.g., or next) block302in the blockchain300. To provide further context for the present disclosure, a high-level discussion of blockchain technology is provided. In general, a blockchain is a public ledger of all transactions that have ever been executed in one or more. A blockchain constantly grows as completed blocks are added with a new set of transactions. In some examples, a single block is provided from multiple transactions. In general, blocks are added to the blockchain in a linear, chronological order by one or more computing devices in a peer-to-peer network of interconnected computing devices that execute a blockchain protocol. In short, the peer-to-peer network can be described as a plurality of interconnected nodes, each node being a computing device that uses a client to validate and relay transactions (e.g., deposits of checks). Each node maintains a copy of the blockchain, which is automatically downloaded to the node upon joining the peer-to-peer network. The blockchain protocol provides a secure and reliable method of updating the blockchain, copies of which are distributed across the peer-to-peer network, without use of a central authority. Validation of the Blockchain can occur in several different ways, using different algorithms. Because all users need to know all previous transactions to validate a requested transaction, all users must agree on which transactions have actually occurred, and in which order. For example, if two users observe different transaction histories, they will be unable to come to the same conclusion regarding the validity of a transaction. The blockchain enables all users to come to an agreement as to transactions that have already occurred, and in which order. Two common schemes for validating blockchain transaction are referred to as proof of work and proof of stake. In a proof of work validation scheme, a ledger of transactions is agreed to based on the amount of work required to add a transaction to the ledger of transactions (e.g., add a block to the blockchain). In this context, the work is a task that is difficult for any single node (e.g., computing device) in the peer-to-peer network to quickly complete, but is relatively easy for a node (e.g., computing device) to verify. In contrast, a proof of stake validation system relies on a participant in the blockchain to have an interest in the accuracy of the blockchain. The validators have to have a stake in the blockchain itself. In these systems, the right to add transactions to the blockchain is provided to validators based on the amount of currency or tokens that they have stored in the blockchain. Generally, the right to add a transaction to the blockchain is randomly or pseudo randomly assigned based on the size of stake of the validators. Another validation system that can be used may rely on the grid telemetry fingerprint. In some implementations, a proof of participation validation enables any node that is able to produce the current grid telemetry fingerprint is able to act as a validator for that section of the grid. Validators may include a memory that enables the validator to track historical grid telemetry fingerprint for a period of time (for example, at least the length of time it takes to validate an entry on the distributed ledger). In some cases, the distributed ledger system can include one or more sidechains. A sidechain can be described as a blockchain that validates data from other blockchains. In some examples, a sidechain enables ledger assets (e.g., a digital currency) to be transferred between multiple blockchains. In some implementations, a grid telemetry fingerprint may be used to identify which blockchain cluster a particular device should join. FIG.4Aillustrates an example of approving a transaction based on a grid telemetry fingerprint. The validation mechanism may include validating a transaction based on the grid telemetry fingerprints. Accompanying the grid instruction is the grid telemetry fingerprint, as determined by the substation402. Other block chain clients along the same line compare the grid telemetry fingerprint provided by the substation to their own grid telemetry fingerprint. For example, a solar array404, a consumer406and a consumer408each compare the grid telemetry fingerprint to their own calculated grid telemetry fingerprint. In this example, the grid telemetry fingerprints match and the instruction or information is validated and added to the block chain ledger. In this manner, each actor on the part of the grid is capable of validating that the instruction or information came from the same part of the grid. In some implementations, validating the grid telemetry fingerprint may be performed as part of another consensus mechanism of the distributed ledger (such as proof of work, proof or stake, etc.) FIG.4Billustrates an example of rejecting a transaction based on a grid telemetry fingerprint. In this example, a third party410(that is not located in the section of the grid that they are trying to manipulate) issues a grid instruction or information along with the grid telemetry fingerprint. As discussed above, the grid telemetry fingerprint generated by two different parts of the grid will necessarily be different. Accordingly, the substation402, the solar array404, the consumer406, and the consumer408each report that the grid telemetry fingerprint does not match. Accordingly, the grid instruction is rejected. In some implementations, the third-party may be barred from further interactions with the block chain, or may be barred from further actions with the block chain for a predetermined period of time. In this manner, third parties that are not part of the electrical grid are prevented from manipulating the electrical grid by issuing fraudulent instructions or information. Further, and some implementations, the value of the grid telemetry fingerprints change frequently enough that it is practically impossible for a third party to obtain the grid telemetry fingerprint and use it to inject instructions before the grid telemetry fingerprint expires. For example, the grid telemetry fingerprint may use grid telemetry data that can change over time. In some implementations, the grid telemetry fingerprint may be used to verify that data that purports to be from a portion of a grid is actually from that portion of the grid. For example, the signature may be used to secure metrics or other data sent between entities on the grid. In some implementations, each device (for example, the substation402, the solar array404, the consumer406, and the consumer408) may have its own unique or quasi-unique device fingerprint based on the electrical characteristics of the device. For example, each computer chip, even if manufactured in the same plant, has a different consumption signature, load signature, etc. . . . Accordingly, each device may be distinctly identifiable for the purposes of tracking transactions in the distributed ledger. Therefore, a system may be able to determine, after the grid instruction is stored on the distributed ledger that the grid instruction was issued by the substation402based on substation402registering its device fingerprint with the distributed ledger. FIG.5is a flowchart of an exemplary process for verifying a transaction. The process500can be performed by a computer system, or specialized hardware integrated with devices connected to an electric grid. The process500generates502a grid telemetry fingerprint. The grid telemetry fingerprint may be generated using grid telemetry information as described above, for example, using voltage, phase angle differences, reactive power information, and/or changes to grid inertia. In some implementations, the process500may generate the grid telemetry fingerprint in response to an entity attempting to place a transaction on a distributed ledger (for example, a block chain). In some implementations, the grid telemetry fingerprint may be generated periodically so that it is available for use as needed. The process500verifies504a transaction. The transaction may have been applied to a distributed ledger and is associated with the grid telemetry fingerprint. The process500may compare the grid telemetry fingerprint associated with the transaction with the grid telemetry fingerprint generated as part of the process500. In some implementations, if the grid telemetry fingerprint associated with the transaction matches the grid telemetry fingerprint generated as part of the process, the process500approves the transaction. It's useful to note that approval of the transaction by the process500does not necessarily mean that the transaction is approved to be applied to the distributed ledger, instead, approval to add a transaction to the distributed ledger may be determined based off of many systems executing a similar process. In some implementations, if the grid telemetry fingerprint associated with the transaction does not match the grid telemetry fingerprint generated as part of the process, the process rejects the transaction. In some implementations, a single process rejecting the transaction may be sufficient to have the transaction excluded from the distributed ledger. In some implementations, excluding the transaction from the block chain may be determined based on several processes operating on different systems In circumstances where a significant number of systems reject the transaction (for example, one process, two processes, three processes, a majority of the processes, etc.) the system that submitted the transaction may be temporarily or permanently barred from sending future transactions. Alternatively, the systems that submit the transaction may need to be cleared or re-approved before it can submit additional transactions (for example, by a systems administrator, grid operator, etc.) FIG.6depicts an example computing system, according to implementations of the present disclosure. The system600may be used for any of the operations described with respect to the various implementations discussed herein. The system600may include one or more processors610, a memory620, one or more storage devices630, and one or more input/output (I/O) devices650controllable via one or more I/O interfaces640. The various components610,620,630,640, or650may be interconnected via at least one system bus660, which may enable the transfer of data between the various modules and components of the system600. The processor(s)610may be configured to process instructions for execution within the system600. The processor(s)610may include single-threaded processor(s), multi-threaded processor(s), or both. The processor(s)610may be configured to process instructions stored in the memory620or on the storage device(s)630. The processor(s)610may include hardware-based processor(s) each including one or more cores. The processor(s)610may include general purpose processor(s), special purpose processor(s), or both. The memory620may store information within the system600. In some implementations, the memory620includes one or more computer-readable media. The memory620may include any number of volatile memory units, any number of non-volatile memory units, or both volatile and non-volatile memory units. The memory620may include read-only memory, random access memory, or both. In some examples, the memory620may be employed as active or physical memory by one or more executing software modules. The storage device(s)630may be configured to provide (e.g., persistent) mass storage for the system600. In some implementations, the storage device(s)630may include one or more computer-readable media. For example, the storage device(s)630may include a floppy disk device, a hard disk device, an optical disk device, or a tape device. The storage device(s)630may include read-only memory, random access memory, or both. The storage device(s)630may include one or more of an internal hard drive, an external hard drive, or a removable drive. One or both of the memory620or the storage device(s)630may include one or more computer-readable storage media (CRSM). The CRSM may include one or more of an electronic storage medium, a magnetic storage medium, an optical storage medium, a magneto-optical storage medium, a quantum storage medium, a mechanical computer storage medium, and so forth. The CRSM may provide storage of computer-readable instructions describing data structures, processes, applications, programs, other modules, or other data for the operation of the system600. In some implementations, the CRSM may include a data store that provides storage of computer-readable instructions or other information in a non-transitory format. The CRSM may be incorporated into the system600or may be external with respect to the system600. The CRSM may include read-only memory, random access memory, or both. One or more CRSM suitable for tangibly embodying computer program instructions and data may include any type of non-volatile memory, including but not limited to: semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. In some examples, the processor(s)610and the memory620may be supplemented by, or incorporated into, one or more application-specific integrated circuits (ASICs). The system600may include one or more I/O devices650. The I/O device(s)650may include one or more input devices such as a keyboard, a mouse, a pen, a game controller, a touch input device, an audio input device (e.g., a microphone), a gestural input device, a haptic input device, an image or video capture device (e.g., a camera), or other devices. In some examples, the I/O device(s)650may also include one or more output devices such as a display, LED(s), an audio output device (e.g., a speaker), a printer, a haptic output device, and so forth. The I/O device(s)650may be physically incorporated in one or more computing devices of the system600, or may be external with respect to one or more computing devices of the system600. The system600may include one or more I/O interfaces640to enable components or modules of the system600to control, interface with, or otherwise communicate with the I/O device(s)650. The I/O interface(s)640may enable information to be transferred in or out of the system600, or between components of the system600, through serial communication, parallel communication, or other types of communication. For example, the I/O interface(s)640may comply with a version of the RS-232 standard for serial ports, or with a version of the IEEE 1284 standard for parallel ports. As another example, the I/O interface(s)640may be configured to provide a connection over Universal Serial Bus (USB) or Ethernet. In some examples, the I/O interface(s)640may be configured to provide a serial connection that is compliant with a version of the IEEE 1394 standard. The I/O interface(s)640may also include one or more network interfaces that enable communications between computing devices in the system600, or between the system600and other network-connected computing systems. The network interface(s) may include one or more network interface controllers (NICs) or other types of transceiver devices configured to send and receive communications over one or more networks, such as the network(s)110, using any network protocol. Computing devices of the system600may communicate with one another, or with other computing devices, using one or more networks. Such networks may include public networks such as the internet, private networks such as an institutional or personal intranet, or any combination of private and public networks. The networks may include any type of wired or wireless network, including but not limited to local area networks (LANs), wide area networks (WANs), wireless WANs (WWANs), wireless LANs (WLANs), mobile communications networks (e.g., 3G, 4G, Edge, etc.), and so forth. In some implementations, the communications between computing devices may be encrypted or otherwise secured. For example, communications may employ one or more public or private cryptographic keys, ciphers, digital certificates, or other credentials supported by a security protocol, such as any version of the Secure Sockets Layer (SSL) or the Transport Layer Security (TLS) protocol. The system600may include any number of computing devices of any type. The computing device(s) may include, but are not limited to: a personal computer, a smartphone, a tablet computer, a wearable computer, an implanted computer, a mobile gaming device, an electronic book reader, an automotive computer, a desktop computer, a laptop computer, a notebook computer, a game console, a home entertainment device, a network computer, a server computer, a mainframe computer, a distributed computing device (e.g., a cloud computing device), a microcomputer, a system on a chip (SoC), a system in a package (SiP), and so forth. Although examples herein may describe computing device(s) as physical device(s), implementations are not so limited. In some examples, a computing device may include one or more of a virtual computing environment, a hypervisor, an emulation, or a virtual machine executing on one or more physical computing devices. In some examples, two or more computing devices may include a cluster, cloud, farm, or other grouping of multiple devices that coordinate operations to provide load balancing, failover support, parallel processing capabilities, shared storage resources, shared networking capabilities, or other aspects. Implementations and all of the functional operations described in this specification may be realized in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations may be realized as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium may be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more of them. The term “computing system” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus may include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus. A computer program (also known as a program, software, software application, script, or code) may be written in any appropriate form of programming language, including compiled or interpreted languages, and it may be deployed in any appropriate form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program may be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. The processes and logic flows described in this specification may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and apparatus may also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any appropriate kind of digital computer. Generally, a processor may receive instructions and data from a read only memory or a random access memory or both. Elements of a computer can include a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer may also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer may be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio player, a GPS receiver, to name just a few. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry. To provide for interaction with a user, implementations may be realized on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user may provide input to the computer. Other kinds of devices may be used to provide for interaction with a user as well; for example, feedback provided to the user may be any appropriate form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user may be received in any appropriate form, including acoustic, speech, or tactile input. Implementations may be realized in a computing system that includes a back end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front end component, e.g., a client computer having a graphical user interface or a web browser through which a user may interact with an implementation, or any appropriate combination of one or more such back end, middleware, or front end components. The components of the system may be interconnected by any appropriate form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet. The computing system may include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. While this specification contains many specifics, these should not be construed as limitations on the scope of the disclosure or of what may be claimed, but rather as descriptions of features specific to particular implementations. Certain features that are described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some examples be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products. A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, various forms of the flows shown above may be used, with steps re-ordered, added, or removed. Accordingly, other implementations are within the scope of the following claims. | 35,301 |
11862972 | DETAILED DESCRIPTION Technology is provided for a system and method to join distributed energy resources (DER) to achieve common objectives. The present technology organizes and/or aggregates DERs in order to achieve common and/or complex objectives, letting the promoter of the initiative to model and design the program. This technology can be applied to Energy Efficiency (EE), Demand Side Management (DSM) or Distributed Energy Resources Management System (DERMS) processes. A DER program may comprise a series of business rules, agreements and engagement processes to manage and distribute DERs. The technology allows for a program manager or administrator to construct a new DER program through the use of user interfaces and templates. DER resources may include but are not limited to Photo-voltaic (PV) solar, Fuel Cells, Energy Storage Systems, Irrigation Pumps, Smart Thermostats, and the like. In DER communities, a limited amount of data may be known about actual nameplate capacity, technology type, locational value, owner preferences, or contributors' behaviors. In some embodiments, DER contributors also include non-human systems. For example, a DER request may be routed and allocated to a non-human system such as a website, an internet of things device, an external system, or other automated system. The technology allows, if specified in the DER program, for the splitting of a DER request into a series of smaller requests that several contributors can respond to and collect each the responses in order to compose a complete an overall response to the original DER request. The technology provides tools and user interfaces to: (1) model the main request, building a schema of the sub-requests it is composed of the constraints existing between sub-requests, and the characteristics of each sub-request, in order to assign each one to the most appropriate DER; (2) engage, profile and maintain the DER aggregation by managing various communication channels from the system to and from each DER and between DERs, both anonymously or explicitly; (3) run the modeled program against a DER aggregation. starting with the creation and assignment of the sub-requests, the monitoring and validation of single result, the reconciliation and aggregation of responses, the application of different levels of priority to every sub-request if required, the maintaining of statistics of responses done and left to do, and the managing of priorities and time of expiration of sub-requests, data and statistics; and (4) administrate and orchestrate whole-system monitoring of the percentage of requests completed for each program, viewing the aggregated response and related key performance indicators, managing rewarding policies for DERs, managing accounting and billing policies, creating and maintaining security and privacy policies for DERs, and defining and activating communication channels and interfaces for DERs or users of the platform. DER program manager users can leverage existing templates based on previous knowledge bases to create DER programs rather than starting from scratch, thereby saving time and cost. Designing a DER program also requires explicitly defining the characteristics requested of the DER resource contributors. DERs must also be profiled according to defined skill sets. The skill sets allow the system to match the most appropriate contributor to execute each sub-request. The speed, level of quality, and other definable attributes can be associated with each DER contributor's response in order to trace the activities and generate statistics but can also be used to update DERs' scores and characteristics. For example, if a program requests frequency regulation, DERs will likely need skills such as “having an energy storage system” and “response time”. During system operation, after each request and completed response in a series of requests and responses for the program, the system will update a score of each DER and maintain statistics and input for a rewarding component of the system. The statistics allow the system to assign each sub-request to the most appropriate DER contributor and improve the global efficiency of the system. With a large number of DERs, there is also a need for evaluating and scoring each contributor to optimize their engagement and meet the requirements of each request requirement and assure maximum quality of service and flexibility. Once the demand for DER grows, there is a need to manage different types of programs and their requests, split them into sub-requests and aggregate results for performance and reliability optimization. Thus, the technology further provides a routing system (sometimes referred to herein as a “routing algorithm”) to manage DER requests with DER resources. In energy communities that include a large number of DERs which are registered to provide services in DER programs, requests are routed and allocated to the DER contributors or a group of the DER contributors. A DER request may include various requests defined in terms of request types and having request attributes. A DER request may include, for example, a demand response event, a resource adequacy request, a load curtailment, a greenhouse gas emission reduction, new job creation, or the like. To route and allocate DER program requests to DER contributors in an energy community, a request including normalized request attributes is received by a routing system. The normalized request attributes correspond to scoring metrics within a profile of each DER contributor. In accordance with the technology, a supervised learning portion of a neural network calculates an initial value based on the scoring metrics of each DER contributor and the normalized request attributes. The initial value associated with each DER contributor profile is input into an unsupervised learning portion of the neural network having weights. In the unsupervised learning portion, the weights are based on measures of behavior of a DER contributor, expressed quantitatively by performance indicators within the profile of each DER contributor. For each profile, a neural network is generated to calculate a fitness metric. To distribute requests among the DER contributors, a stochastic model is used to select a set of profiles based in part on the fitness metric and in part on the request attributes. The request is then routed to the DER contributors associated with the selected set of profiles and data results are collected, measured, and validated from each individual and the selected DER contributor. FIG.1Ashows overview of the use of the present technology. In one embodiment, a program designer or administrator (i.e. one or more users50) accesses the system100via a web interface over internet connection using a common web browser. It should be recognized that any number of different types of interfaces may be provided, the system100may be a standalone system not connected to a network or be connected to a number of other systems (and the DERs) by a local or other network connection. The interface for the DER program designer and administration allows every registered DER manager user to start, promote, and run a new DER program for a community of available distributed energy resources. By way of example, a program manager can create a new DER program52, by selecting pre-defined templates from a system repository or by starting from scratch. After completing all the required DER program personalization and configuration tasks (i.e. defining business rules, contract and reward policies, DER skills, and escalation process), the DER program manager can start promoting it and building a DER community at54. This includes engaging DER contributors to subscribe to the platform, sign the service enrollment contract, and register their DERs to be contributors56. Once the DER community is formed, with DER contributors subscribed, and their DERs registered, analyzed, and scored, the system is ready to operate at58, and the DER manager can start using the system to provide services, creating requests through the portal that are dispatched downstream to the DER contributors which can use their portal access to monitor their DER operations (i.e. response status, service level, rewards, etc.). FIG.1Bshows an overall architecture of the system100that implements the present technology. The system comprises a program designer component120, a DER evaluation and dispatching component130, a community builder140and a community admin component150. Various mobile and web interfaces102,104,106and108, as well as an internet of things (IoT) interface120may be included in the system. The core of the system is the DER evaluation and dispatching component130which includes the DER routing system described herein. In one aspect, the DER evaluating and dispatching component130includes a DER scoring engine, routing system including a matching algorithm and a set of workflow engines which are able to interpret program schemas, business rules and constraints defined in the DER program. The program designer120comprises a tool to create and edit programs for DERs where business rules, legal contracts, types of resources, assignments, and rewarding policies are defined. These DER programs can be designed from scratch or, starting from a set of program templates, available in a system library. The program designer120is accessible to an administrator (402inFIG.4) via a web interface102or mobile interface104. Program designer120allows program designers and administrators to create or modify programs, interact with available applications, and monitor active community members and processes. After a program is designed and instantiated on the system100the program designer120, the community administrator may create DER users who interact with the program run by system and register distributed energy resources with the program. Users, DERs, business rules, service contracts, workflows and all other data are represented as schemas or data schemas in the system. The community builder140comprises tool to manage the supply side of the DER program, providing a set of programs to engage and subscribe customers, register and analyze available distributed energy resources, collect data from various data sources and external devices, and enable DER sale transactions with technology vendors in a digital marketplace. The Community builder140is accessible to users (404inFIG.4) via a web interface106or mobile interface108. The community administration component150is a tool to manage the system security for user access and identity management, monitor the operations at both program and DER contributors' level and manage rewarding DER contributors. FIG.2shows how various components work together in a networked environment, and how one or more instances of system100may be accessible to various users. One or more instances of the system100a,100b,100cmay be coupled by a network202and can work in parallel, implementing different DER programs based on different business scenarios and orchestrating several DER contributors. The network202may itself be coupled to a wide area network such as the internet204, providing various types of client access including a mobile interface210, web interface220, email interface and messaging interface240. DERs can be connected directly to the system or accessed through the Internet, via cloud access channels or whatever IoT application programming interface (API) channel the application instance integrates over the communication layer. A single application instance has a set of rules determining users' grants of access differentiated per access channel. Users and DER contributors can interact with the system through different access channels. For example, a DER contributor to whom a sub-request has been assigned via an SMS notification can check the details of the request accessed with mobile device interface, and respond via the mobile interface, and/or switch to another interface such as a personal computer to complete the sub-request. User credentials will grant unique access even if performed from different access channels. FIG.3illustrates conceptually how a new DER program is designed and implemented. The system includes a library302including templates for business rules312, contracts314, DER types316, rewards318and routing rules320. To reduce the time and skill required to create a new DER program, an intuitive user interface for users provides access to the library302to allow the user to select and construct a specific DER program350comprising a set of business rules312a, distributed energy resource types316a, contracts314a, rewarding policies318aand routing preferences320a. The administrator or program designer402builds the DER program350by selecting the most appropriate template from a library302of pre-designed programs. Then, the designer can customize or personalize elements such as business rules, reward or contract policies, DER type, etc. to better reflect the specific program requirements. The editing environment may comprise a graphic user interface, allowing the designer to build the DER program without having to deal with low level code. Once such a DER program is created, the solution can obtain the contribution of engaged DER contributors. A request from a DER program may or may not be solved by the DER contributors. Within any defined program (350), a request may or may not converge toward an optimal solution depending on the type of request. A main request can be decomposed into simpler sub-requests and sent to contributors which respond so the main request can have a solution as soon as each sub-request is completed. For example, a typical Energy Storage System (ESS) grid service use case is frequency regulation, which requires high frequency data and quick response time. In this use case, a utility program administrator may need to quickly send a request to regulate frequency in a geographic area where imbalances are increasing. As such, they would send a main request to all the known DER contributors within the geographic area, and the system would decompose the main request to target only those DERs that have an ESS and are able to respond within a certain time period. These ESS DERs would each perform a quick ramp up or ramp down based on the grid request requirement, and in aggregate the overall grid frequency would converge back to nominal rates. In another embodiment a demand/supply matching system allows a multitude of requests to be sent to a multitude of DER contributors. As another example, a resource adequacy request may be sent to DER contributors in an area of high solar PV penetration. As the solar production decreases late in the day, these other DERs (ESS, fuel cell, etc) may be required to ramp up to meet demand, and the main request for X kW in supply would be evenly split among Y contributors, where each contributor is able to supply X/Y kW to the overall request. FIG.4is a more detailed representation of the architecture of the system100and illustrates how various individuals (administrators, managers, designers, DER contributors) interact with the system100. An administrator or program designer402generally interacts with the DER program designer tool120. The program designer120may include a library (such as library302) of business rules122, contract templates124, routing preferences125, skills126and reward policies128. It should be understood that the elements contained in the library are illustrative only and many additional types of templates may be included therein as the needs of DER programs change over time. DER program creation is performed through the DER program designer120. The access to the program designer120is made by a presentation layer which lets administrators and designers402interact through different user interface channels such as, but not limited to, a web interface102and mobile interface104. Changes to a program can be immediately applied or stored for future use. If a change impacts a deployed program, the administrator can determine whether to let the program terminate with the previous behavior or change it immediately. Every applied change modifies the DER program design. DER program modifications include business rules, DER types, contract and rewarding policies, and priority and routing policies. With the program designer120, is possible to change the way the program creates requests, assigns sub-requests, allows the DER contributors interact with the system, rewards or penalizes a contributor, and controls the way a DER contributor subscribes to a contract. It can also monitor DER contributor service performance and service level agreement. The user interface to the DER program designer120also allows access to previews of the DER program before its rollout in the marketplace, giving a final overview for confirmation of what will be run and presented to each DER contributor before deploying it in the marketplace. Also shown inFIG.4are the components of system100generally utilized by a program manager or managers406(who may be the same as or different than the designer/administrator402). Managers406interact with DER evaluation and dispatching component130and the community administration component150. The DER evaluation and dispatching component130includes a scoring component131, a validation component132, a plan component134, a monitoring component135, an escalate component136and a dispatch component138. The DER evaluation and dispatching component130also includes is a workflow engine430which runs each single request made to a DER program, links different DER sub requests, and orchestrates the overall program. The DER scoring facility131tracks profiles and performances of DER contributors of the program in order to optimize the sub request routing and assignment activity. DER evaluation and dispatching plan component130contains the sub-components which a data model containing all information needed to run DER requests according to specific business processes defined for the DER program. The DER evaluation and dispatching component130utilizes workflows to select the DER contributors most appropriate for the specific request. DER monitoring135tracks and DER validation132validates each DERs performance over time allowing for continuous DER scoring updates, along with skill and rewarding management. As discussed below, the plan131, scoring132and dispatching138components may take the form of a routing system which, based on a specific set of DER program goals and a set of available DER profiles, splits a complex DER request into sub-requests, if the DER program required it, then organizes and assigns sub-requests to the available DER contributors, thereby maximizing the result in terms of time, cost, and user satisfaction in the planning and operational dispatch process. Even if a DER program's rules and design do not change until an administrator changes them, the behavior of the system may change over the life of the program because the program may evolve to adapt itself to the program requests and DER contributor skills, availability, and characteristics. The community administration component150includes a member manager152, a reward manager154, a program manager156and a security manager158. As illustrated inFIG.5, a manager406can monitor DER members using manager152, check that rewards are well assigned using the reward manager154, determine whether the DER program is running as expected using manager156, and assess program security using manager158. The reward management component154, is responsible for collecting statistics of usage, and rewarding DER contributors based on such statistics and according to the reward policy defined for the program (i.e. money, fidelity points, grants, score, etc.). Additional components may be added over time to deal with new business requirements and new users' designs. FIG.4also illustrates how end users404(i.e. DER contributors) interact with system100. In general, users404interact with the DER evaluation and dispatching component130and the community builder140. The community builder140includes an owner engagement component142an owner registration component144, a DER registration component145, an analytics component146, a marketplace148and a data collection component149. The users404may be DER contributors, which have been through the DER registration process managed by the community builder registration component145. Users404may be DER technology vendors which join the DER digital marketplace148. Internet of Things devices can exchange data and information with the system via an IoT interface120. As an example of the system/user interaction, a DER program manager402may access the system100and select a DER program though which a request will be submitted to the registered DER contributors via a user interface102/104. The request is stored in the DER evaluation and dispatching component130, taken in charge by workflow engine430, and then analyzed and dispatched to the multitude of DER contributors. The workflow activated by this request will determine the action to be performed. In one example, a DER dispatch request for a demand/response program is created. The system, based on the data of the DER evaluation and dispatching component such as DER skill management data or priority, will determine the set of best DER contributors to participate in the demand response event and complete each sub-request. Once the contributors have been selected by the system, they are notified when to drop their DER load through the preferred or subscribed communication channel stored in their registration profile (i.e. text, email, mobile app, machine to machine, etc.). Selected contributors will then need to respond to, so they individually or through one or more processing devices may access the system in order to respond to the sub-request. If a DER contributor is able to respond, it will drop the load as required using the preferred or configured communication channel, which measured, evaluated and confirmed by the DER evaluation and dispatching component for confirmation and rewarding. The DER program manager will receive notifications and updates on the sub-requests progress, and may access the system to monitor the demand response event status, sub-request failures, system errors, etc. According to these results, the system will update the DER program status, and the DER contributors scoring and profile, and will provide input to the DER rewarding system. Numerous other use scenarios are possible with system100. FIG.5is high-level conceptual diagram of how a program request is sub-divided and addressed by system100. A DER program request is decomposed into several sub requests (DER sub-request1, DER sub-request2. . . DER sub-request n) that can be executed in parallel, in series or in a sequence defined by a set of processing rules. The request produces a set of sub-responses (DER sub-response1, DER sub-response2. . . DER sub-response n) that the system is able to aggregate in order to provide the DER program response to the initial DER program request. The example diagram ofFIG.5represents one specific kind of request. Not every DER program request need be designed in a way to be split and sent to many contributors. Sometimes, for example, a DER program business rule could require sending requests for a specific DER contributor directly, due to location or priority constraints. FIG.6shows a high-level diagram of the application architecture of the present technology. Main application modules and data flows are depicted. DER program rules and policies are stored in the DER routing system database671, which is accessible to all other application modules through the DER routing system interface672. Interface672implements a common set of objects and APIs used to easily access and manipulate data. The workflow engine673(equivalent to engine430inFIG.4) handles all automatic operations in the system, such as state transitions, data transformations and integrity checks, actions, interrupts and notifications. The user interface module674handles the interactions with all users (DER program designers, DER contributors, community administrators, etc.) and manages all manual activities in the system, by interacting with the workflow engine430, the program designer120, and the community builder140. Users can interact with the user interface through the user multimedia access channel module677that ensures accessibility through various channels (seeFIG.1BandFIG.4). The program designer678allows administrators to create a DER program, setting up business rules, policy and reward management679, executed by the workflow engine, and implements the rewarding mechanism for the contributions of DERs. The community builder676allows DER contributors to sign up and register their DER and participate in DER programs; the DER scoring module677analyzes the DER from several standpoints and defines scores and skills to be used by the workflow and exchange with the DER Matching Algorithm. FIG.7shows a high-level diagram of the DER routing system object-oriented data model. (Although the system is illustrated with respect to an object oriented data model, relational database implementations can be also utilized). The data model consists of a number of tables or collections, conceptually grouped by referential consistency, where all static, meta, and dynamic data are stored. The DER Program is modeled by objects, attributes, relations, rules, constraints and DER scores tables. DER program requests are stored in request tables, while DER contributors and DER program workflows are modeled by DER tables, sub-requests, rewards, actions and runtime tables. Interface tables are included to allow intercommunication with external systems (i.e. data warehouse, billing, CRM). FIG.8represents the internal architecture of the DER routing system interface672. All external modules access persistent data through this module, interacting with an Object-Oriented Data Model Engine, responsible for mapping structured data, stored in the database illustrated inFIG.7, to object classes and APIs, reflecting the conceptual data model. FIG.9shows an example flow diagram describing a DER program request lifecycle, in terms of actors, manual and automatic tasks and transitions, and states. At902, a DER program manager selects a DER program from his available list, creates and submits a request to his DER community (through a user interface) at904. At906, the system searches for the best suitable DER contributor or set of DER contributors, and it submits one or many sub-requests to them at908, notifying the contributor at910. The system waits for a DER response at912but if the DER contributor is not able to respond to his sub-request within a defined timeframe at914, then a new DER contributor is selected by the system by looping back to906. If a DER contributor's response is provided at916within the timeout period, it is collected, measured and validated by the system at918. At920if the DER contributor's response is accepted, then the sub-request is closed922(and archived for future use) and aggregated by the system to close the initial DER program request; DER contributor skills are updated at926, and rewards are assigned at928. Otherwise, if the response is not accepted at920, else a new contributor is selected, and conflict is handled between DER program manager and DER contributor at922. Once all DER responses are collected at924, the program request is closed at930. FIG.10is a block diagram of a network device1000that can be used to implement various embodiments of the present technology. Specific network devices may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device. Furthermore, the network device1000may contain multiple instances of a component, such as multiple processing units, processors, memories, transmitters, receivers, etc. The network device1000may include a central processing unit (CPU)1010, a memory1020, a mass storage device1030, and an I/O interface1060connected to a bus1070. The bus1070may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus or the like. The CPU1010may comprise any type of electronic data processor. The memory1020may comprise any type of system memory such as static random-access memory (SRAM), dynamic random-access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), a combination thereof, or the like. In an embodiment, the memory1020may include ROM for use at boot-up, and DRAM for program and data storage for use while executing programs. In embodiments, the memory1020is non-transitory. In one embodiment, the memory1020includes an input module1020A, a profile module1020B, a supervised learning module1020C, an unsupervised learning module1020D, a stochastic module1020E, a scoring module1020F, a feedback module1020G and an output module1020H. Such modules implement a routing system or “matching algorithm” as discussed herein. Any one or more of these elements may be stored as instructions on the mass storage device1030. The instructions may be operable to control the CPU1010to perform the functions described above with respect to these elements. In alternative embodiments, each of the modules may be implanted in hardware, using, for example, programmable logic devices and/or systems. The input module1020A is configured to receive a DER program request including a set of normalized request attributes. Each request attribute includes an identifier of a particular DER skill and a normalized quantifier indicating the importance of the DER skill for providing a response to the request. The mass storage device1030may comprise any type of storage device configured to store data, programs, and other information and to make the data, programs, and other information accessible via the bus1070. The mass storage device1030may comprise, for example, one or more of a solid-state drive, hard disk drive, a magnetic disk drive, an optical disk drive, or the like. The mass storage device may also store the any of the components described as being in or illustrated in memory1020to be read by the CPU and executed in memory1020. The mass storage device may comprise computer-readable non-transitory media which includes all types of computer readable media, including magnetic storage media, optical storage media, and solid-state storage media and specifically excludes signals. It should be understood that the software can be installed in and sold with the network device. Alternatively the software can be obtained and loaded into network device, including obtaining the software via a disc medium or from any manner of network or distribution system, including, for example, from a server owned by the software creator or from a server not owned but used by the software creator. The software can be stored on a server for distribution over the Internet, for example. The network device1000also includes one or more network interfaces1050, which may comprise wired links, such as an Ethernet cable or the like, and/or wireless links to access nodes or one or more networks1080. The network interface1050allows the network device1000to communicate with remote units via the networks1080. For example, the network interface1050may provide wireless communication via one or more transmitters/transmit antennas and one or more receivers/receive antennas. In an embodiment, the network device1000is coupled to a local-area network or a wide-area network1080for data processing and communications with remote devices, such as other processing units, the Internet, remote storage facilities, or the like. As used herein, a request may be specified by a program administrator, utility manager or other entity by submitting, via a user interface, one or more service requests to the DER contributors of the program. Each request may have one or more request attributes, as illustrated inFIG.11. Each request may take the form of a XML or JSON structured object which may be parsed by the system, though the particular format used by the system may vary. Although a request may be generated come from a user interacting with the system via the UI, in other embodiments, the requests may be received by external systems communicating with system100. Referring now toFIG.11, an exemplary request attribute tree1100according to various embodiments is depicted. The request attribute tree1100is an organization of the request attributes and corresponds to the various scoring skills of the available distributed energy resources, for example, DER contributors. In this instance, the request is a demand response program request1102for a distribution system operator. The DER program manager, i.e., DER Program Manager402, initiating the DER program request may identify the request as an ‘Operational’ request1104. Other types of requests may be classified as Economic, Environmental or Financial. Each type of request may have its own set of attributes, not all of which are illustrated inFIG.11The ‘Operational’ request1104is assigned with an intermediate value1106of twenty. If the DER program manager cannot further define the request, the intermediate value is assigned to all the leaves (grid resiliency, facility resiliency, grid load reduction, facility load reduction, feeder line consumption reduction) depending from the ‘Operational’ request1104. In this example, the DER program manager has specified that the ‘Operational’ request1104is a ‘Grid Load reduction’1108having an intermediate value1110of twenty. In this example, the request is further identified as a ‘1h ahead’ request1112. Within the request attribute tree1100, the ‘1h ahead’ request is associated with a DER skill value1114of twenty. The DER skill value1114may be based on a DER program template used to define the request, be specified by the DER program manager, or be based on industry standard criteria, for example. As is apparent to those skilled in the art, the intermediate values1106and1110may have a value other than twenty. Further, the skill value1114may be a different value. Further, the task attribute tree1100is shown for the purposes of illustration only. As will be apparent to those skilled in the art, other data structures can be used to assign DER program request attributes. The request attribute values, once determined, are normalized according to known normalization techniques. Referring back toFIG.10, the profile module1020B is configured to access profiles of DER contributors. For each DER contributor, a profile includes a plurality of scoring metrics and a plurality of performance indicators. In some embodiments, the profile also includes DER metadata information about the owner such as preferences, location, type, nameplate capacity, or the like. The scoring metrics correspond to the particular skills defined by the request attributes and indicate the DER contributor's ability level for each particular DER program request type. The skill metrics are determined based on the DER scoring module206. The data in the profile may be imported from another system or platform. In some embodiments, the DER scoring metrics are also based on whether a previous request sent by the DER program manager was accepted and responded. Referring back toFIG.10, the DER scoring module1020F is configured to continuously process DER contributor's data and metadata, evaluate, generate and update scoring metrics for each DER contributor's profile. The scoring module generates or updates these scoring metrics for each DER contributor based on its set of skills assigned to each at the DER Program Design step. As such, the module performs a variety of types of score calculations at each iteration and is designed to be extendable and flexible to allow other skills and scores to be added in the future. For example, a DER planning request may require the scoring of a set of simulated DER profiles according to operational, financial, economic, and/or environment attributes. Such calculations would require the use of simulated load profiles, estimated financial projections, and industry standard metrics to derive a set of DER contributors to deploy. For example, one of the scores may be the DER Contributor's ability to aid in local grid resilience. The equations to calculate this resilience is DER type-specific and are as follows: BatteryGridResilience=Btime×PBFLDPVGridResilience=PVtime×(PPVremain-FRF×D)FLD where Btime=Available battery discharge time, the average amount of time a battery will be able to discharge at full capacity. The battery discharge time is calculated by determining how long each battery will discharge from its current state of charge to a minimum considering the battery power capacity (kW) and energy capacity (kWh). PB=Battery Power Available, represents the power of a Battery Energy Storage system. It is equal to the battery's power capacity in kW. FLD=Feeder line demand, represents the feeder line load in kW. D=Average facility demand, represents the average facility load in kW. FRF=Facility resilience factor represents the percentage of the DER contributor's owner's desired amount of personal resiliency from their DER. PPVremain=Average PV power output for the remainder of the day's generation, represents the average PV power output for the duration of its daytime production PVtime=Average PV generation duration: represents the average duration after a disturbance that a PV system will be generating. On the other hand, a DER operational request to lower grid consumption by x % may require instantaneous metrics corresponding to real time demand, real time production, real timeline segment impact, pricing signals, etc. The scoring module1120F will use the following equations, which again are DER type-specific, to calculate the DER contributor's potential to participate in such an event: If DER potential power output is less than average facility demand: PotentialLoadReduction=PB+PPVdaytimeavgD Additionally, the potential peak load reduction benefits can be evaluated: PeakLoadReduction=PB+PPVpeakDpeak These equations are used to quantify a DER contributor's ability to cover a facility's load and therefore shed some grid load to serve the event. Such examples show the diversity of the scoring module and its requirement to be flexible and extendable. In general, however, the scoring criteria are divided into categories that pertain to relevant energy stakeholders' objectives: operations (grid impact and DER optimization), finance, environment, and economics. Referring now toFIG.12, a table1250depicting the scoring metrics of DER contributors according to various embodiments is shown. The table1250includes DER scoring metrics1252which correspond to the DER program request attributes of the request attribute tree1200. For the purposes of illustration, the table1250includes the scoring metrics for each request attribute of DER contributor A1254, DER contributor B1256, DER contributor C1258, and DER contributor D1260. The performance indicators within the profile module1020B include behavioral factors of a DER contributor. Typically, the performance indicators are cumulatively calculated as a DER contributor is allocated requests and provides responses to those requests. To illustrate, one performance indicator is “reliability” which is measured by dividing the number of requests that the DER contributor has responded to by the number of requests that the DER contributor has been allocated. Another example is “commitment” which is measured by dividing the number of requests that the DER contributor has accepted from the routing system by the number of requests that the DER contributor has been allocated. Further performance indicators may be measured based on, for example, an amount of time to accept an allocated request or an amount of time to provide a response to the allocated request. Referring back toFIG.10, the supervised learning module1020C is configured to calculate at least one initial value for each DER profile based on the at least one normalized request attribute and the plurality of DER scoring metrics. For each request attribute associated with the request, an initial value is generated based on the value of a corresponding scoring metric within the profile of the DER contributor. The initial value may be zero for a request attribute if the DER contributor has a scoring metric having a zero value or if the DER program manager indicated that request attribute is not relevant to the current request. The unsupervised learning module1020D is configured to calculate a fitness metric for each DER profile based on the initial values. The unsupervised learning module1020D uses a neural network for each DER profile. The initial values for each DER profile are input into the unsupervised learning module1020D. The unsupervised learning module1020D uses a neural network that includes weighting factors that are based on the plurality of performance indicators within the DER profile. Neural networks are generally known to those skilled in the art. Referring now toFIG.13, a diagram of an exemplary neural network1300according to various embodiments is shown. The neural network1300includes a supervised learning portion1302and an unsupervised learning portion1304. The supervised learning portion1302includes normalized DER program request attributes An1306and score metrics Scn1308both as described in connection withFIG.11. The supervised learning portion1302calculates initial values1310according to the formula: In=An*Scn While the calculation of the initial values is shown as part of the neural network, it will be apparent that other techniques may be used. The supervised learning portion1302is implemented by the supervised learning module208. The unsupervised learning portion1304, implemented by the unsupervised learning module1020D, includes a neural network having weights wm1312between nodes. The unsupervised learning portion1304receives the initial values1310and calculates a fitness metric1314. The value at each secondary node of the unsupervised learning portion1304is: Σ=Σ(IN*wm) As is apparent to those skilled in neural networks, at each successive node, the value is calculated in similar fashion. It should be noted that each weight1312may be different from the other weights. From the unsupervised learning portion1304, the fitness metric1314associated with the DER contributor's profile on which the neural network is based is outputted. Returning to the demand response program ‘1h ahead’ request1112example,FIG.14Adepicts a neural network1400associated with the DER contributor A1254ofFIG.12according to various embodiments. In the neural network1400, the normalized request attributes1402for the demand response event as described in connection withFIG.11are input into the supervised learning portion1302. The scoring metrics1404of DER contributor A354as described in connection withFIG.11are also included in the supervised learning portion of the neural network1400. The initial values1406are calculated as discussed in connection withFIG.13. Based on the initial values, an unsupervised learning portion1304of the neural network1400calculates a fitness metric1408of4800for the DER contributor A354. The weights in the neural network1400are all depicted as the value two; however, as will be apparent to one skilled in the art, the weights may vary. FIG.14Bis a depiction of a neural network1430associated with the DER contributor B356ofFIG.13according to various embodiments. The neural network1430receives the same task attributes1402as the neural network1400. The supervised learning portion1302of the neural network1430, however, includes the scoring metrics1432of DER contributor B356. Based on the initial values1434calculated by the neural network1430, the unsupervised learning portion1304of the neural network1430calculates a fitness metric1436of1920for the DER contributor B356. FIG.14Cis a depiction of a neural network1460associated with the DER contributor C358ofFIG.13according to various embodiments. The neural network1460receives the same task attributes1402as the neural network1400. The supervised learning portion1302of the neural network1460, however, includes the scoring metrics1462of DER contributor C358. Based on the initial values1464calculated by the neural network1460, the unsupervised learning portion1304of the neural network1460calculates a fitness value1466of960for the DER contributor C358. FIG.14Dis a depiction of a neural network1490associated with the DER contributor D360ofFIG.13according to various embodiments. The neural network1490receives the same task attributes1402as the neural network1400. The supervised learning portion1302of the neural network1490, however, includes the skill metrics1492of DER contributor D360. Based on the initial values1494calculated by the neural network1490, the unsupervised learning portion1304of the neural network1490calculates a fitness metric1496of480for the DER contributor D360. Returning toFIG.10, the stochastic module1020E receives the fitness metrics calculated by the unsupervised learning module1020D. The stochastic module1020E is configured to select a DER contributor's profile or a set of DER contributor's profiles by implementing a stochastic model using the fitness metric. Because neural networks are designed to select a single best pathway based on feedback, a neural network by itself consistently routes similar requests to the same DER contributor. To avoid allocating too many requests to a single DER contributor and so minimizing program response failure risk, the stochastic module1020E is included in the routing system870. The stochastic module1020E randomly selects profiles associated with a fitness metric in order to distribute program requests among DER contributors who would not otherwise be selected because another DER contributor has a higher fitness metric for a specific request. FIG.15is a depiction of a selection of a DER contributor according to various embodiments. In some embodiments, a list of the DER profile is sorted according to fitness value. To continue the demand response program ‘1h ahead’ request312example, the table1502includes a sorted list of the fitness metric508of DER contributor A354from neural network500as described inFIG.5A, the fitness metric536of DER contributor B356from neural network1430as described inFIG.5B, the fitness metric1466of DER contributor C358from neural network1460as described inFIG.14C, and the fitness metric1496of DER contributor D360from neural network590as described inFIG.5D. In some embodiments, a portion1504of the profiles may be pre-selected based on a threshold fitness metric, including but not limited to, for example, a percentile threshold, or the like. For example, the portion1504is based on a percentile threshold which pre-selects the profiles having a fitness metric within a top 50% percentile of the fitness metrics. The stochastic model1506, implemented by the stochastic module1020E, may select a DER profile based on a Gaussian distribution, a lottery, or the like. In embodiments where the selection is based on a lottery, each DER profile is assigned a range of numbers according to a probability of being selected based on the fitness metric. A random number is generated. The DER profile that is assigned to a range that includes the random number is selected for the program request. Returning to the above demand response program ‘1h ahead’ request1112example, DER contributor A354and DER contributor1456may be pre-selected because both are associated with a fitness metric in the top fiftieth percentile. By normalizing the fitness metrics of both profiles, the profile of DER contributor A354has a 71% chance of being selected and the profile of DER contributor B356has a 29% chance of being selected. Based on these probabilities, the profile of DER contributor A354is assigned a range of numbers from zero to 0.71 and the profile of DER contributor B356is assigned a range of numbers from 0.72 to 1.00. A random number is generated. If the random number is 0.89, the task is allocated to the profile of DER contributor B356even though DER contributor B356has a lower fitness metric than DER contributor A354. The output module1020H is configured to route the request to the DER contributor or the set of DER contributors associated with the selected profiles. The feedback module1020G is configured to collect feedback from at least two sources. The first source of feedback is based on the behavior of the DER contributor in responding to the request. For example, data may be collected based on whether the DER contributor accepts the request, an elapsed amount of time for the selected DER contributor to accept the request, whether the DER contributor provided a response to the request, an elapsed amount of time for the DER contributor to provide a response to the request, a number of times that the DER contributor has responded a previous request, whether the selected DER contributor has accepted a request within a time-out period, whether the selected DER contributor has provided a response to the request within a time-out period, or the like. The second source of feedback is the DER program manager who submitted the request. This feedback includes collecting, measuring, analyzing and validating response data from the DER contributor. Additionally, the output module handles the mapping of the selected DER profiles to actionable requests for each DER contributor to take. For example, if DER contributor B from the previous example is chosen to respond to the ‘1h head’ request, the output module must map this selection to a set of capacity and duration values for the contributor to perform. In this example, the output module may determine that DER contributor B must reduce 10 kW of load for 4 hours of duration. The feedback module1020G is configured to update the profile of the DER contributor in the DER scoring module206based on the feedback. For example, if the response is validated and accepted, the scoring metrics associated with the request attributes may be increased or weights within the neural network may be modified as is discussed in connection withFIG.16. The feedback based on the behavior of the DER contributor may be used to update weights within the neural network according to a learning function. Referring toFIG.16, an updated neural network1600associated with the DER contributor B356according to various embodiments is depicted. To continue the demand response program ‘1h ahead’ request1112example, if the response provided by DER contributor B356is accepted, the scoring metric1602associated with the ‘1h ahead’ skill is increased from the value forty to the value forty-one. The scoring metric may be modified by incrementing the previous score level by a predefined amount for each response provided by the DER contributor that is validated and accepted. Other methods of updating the score metric will be apparent to those skilled in the art. The unsupervised portion1304is updated by modifying the weights and/or the topology of the neural network1600according to known methods. In one embodiment, the weights in the neural network1600are generated according to a learning function such as: wm(new)=wm+s/n where wm(new) is the updated weight between the designated nodes, wm is the previous weight between the designated nodes, s is +1 if the response was validated and accepted and −1 if the response was rejected, and n is the incoming connections on the node. Using this equation, new weights1604,1606, and1608are calculated along one possible path through the neural network. In this example, because each possible path in the neural network530ofFIG.5Bhas equal weights, the selection of the weights that are modified is random. In some embodiments, only the most heavily weighted path is updated. The routing system as described in connection withFIGS.10-17therefore allows DER program requests to be allocated to DER contributors based on known information stored as score metrics and behavioral information stored as performance indicators. As each DER contributor is allocated requests and provides responses to those requests, the neural networks become more refined and are more able to accurately measure fitness values associated with each DER contributor. Further, the stochastic model allows for distribution of the requests to DER contributors who may be able to provide a response to the request but would not have been chosen by merely comparing fitness metrics calculated by the neural networks. FIG.17is a flowchart of a method1700for allocating a request to a DER contributor according to various embodiments. The method1700may be performed by the routing system104. In step1702, a DER program request is received. The request includes at least one normalized score attribute. The step1702may be performed by the input module202. In step1704, DER contributor profiles are accessed. Each profile is associated with a DER contributor and includes score metrics and performance indicators. The step1704may be performed by the profile module204integrating with the DER scoring module206. Initial values for each DER profile are calculated in step1706. The initial values may be calculated by the supervised learning module208. A fitness metric for each DER profile is calculated in step1708. The step1708may be performed by the unsupervised learning module210. In step1710, a DER profile or a set of DER profiles are selected by, for example, the stochastic module1020E. In step1712, the output module maps the selected DER profiles to a set of actionable tasks that each DER contributor is capable of making according to its skill set. In step1714, the request is routed to the DER contributor associated with the selected DER profile or set of DER profiles by, for example, the output module1020H. In an optional step1716, feedback is collected from the DER program manager who initiated the request and/or based on the behavior of the DER contributors associated with the selected DER profiles. The feedback may be collected by the feedback module1020G. While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the following claims and their equivalents. For purposes of this document, it should be noted that the dimensions of the various features depicted in the figures may not necessarily be drawn to scale. For purposes of this document, reference in the specification to “an embodiment,” “one embodiment,” “some embodiments,” or “another embodiment” may be used to describe different embodiments or the same embodiment. For purposes of this document, a connection may be a direct connection or an indirect connection (e.g., via one or more other parts). In some cases, when an element is referred to as being connected or coupled to another element, the element may be directly connected to the other element or indirectly connected to the other element via intervening elements. When an element is referred to as being directly connected to another element, then there are no intervening elements between the element and the other element. Two devices are “in communication” if they are directly or indirectly connected so that they can communicate electronic signals between them. Although the present disclosure has been described with reference to specific features and embodiments thereof, it is evident that various modifications and combinations can be made thereto without departing from scope of the disclosure. The specification and drawings are, accordingly, to be regarded simply as an illustration of the disclosure as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the present disclosure. The foregoing detailed description has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the subject matter claimed herein to the precise form(s) disclosed. Many modifications and variations are possible in light of the above teachings. The described embodiments were chosen in order to best explain the principles of the disclosed technology and its practical application to thereby enable others skilled in the art to best utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope be defined by the claims appended hereto. | 57,274 |
11862973 | DETAILED DESCRIPTION OF THE EMBODIMENTS The technical solutions in the embodiments of the present disclosure will be clearly and completely described herein below with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely part rather than all of the embodiments of the present disclosure. On the basis of the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure. With regard to the above-mentioned problem, the present disclosure provides an optimization method for capacity of a heat pump and power of various sets of energy source equipment in an energy hub, which can directly optimize an original model without performing much processing on a problem model. In order to make the above objective, features, and advantages of the present disclosure more apparent and more comprehensible, the present disclosure is further described in detail below with reference to the accompanying drawings and specific implementation manners. Embodiment 1: FIG.2is a flowchart of an optimization method for capacity of a heat pump and power of various sets of energy source equipment in an energy hub of the embodiments of the present disclosure. The method includes: (1) establishing an energy hub model containing a natural gas boiler, an electric boiler, a cooler, and a heat pump; (2) establishing an upper-layer model of double-layer optimization to solve optimal capacity of the heat pump; (3) establishing a lower-layer model of double-layer optimization to solve optimal power of the various sets of energy source equipment; (4) solving the upper-layer model by using a quadratic function-based binary search algorithm; (5) solving a lower-layer model by using a multi-objective evolutionary algorithm NSGA-II; (6) integrating double layers of optimization models to obtain an optimal solution. Optionally, the energy source equipment includes a natural gas boiler, an electric boiler, a cooler, and a heat pump. Optionally, the step (1) specifically includes: An energy source supply network is established according to energy supply equipment in the energy hub, where the input of the energy hub includes electric energy and natural gas; and the input of the energy hub includes heating load, cooling load, and additional electrical load. Optionally, the step (2) specifically includes that: In the energy hub, the power of various sets of equipment can be optimized only after the capacity of the various sets of equipment is set, which is obviously a problem about master-slave optimization. The double layers of optimization models are commonly used models for solving the master-slave optimization problem. The first objective function of the upper-layer model is to minimize the total annual cost Ctotof an energy hub system: minCtot=CinitHP+(1+i)n-1i(1+i)nCop(1)CinitHP=φHPQHP,max(2) Where, CinitHPis the initial cost of the heat pump, n=10 is the operating years of the energy hub, i is the operation and maintenance growth rate of the energy hub, Cop, is the annual operation cost and is provided by the lower-layer model, φHP1218 yuan/kw is the price per unit heat pump capacity, and QHP,maxis the capacity of the heat pump. The second objective function of the upper-layer model is to minimize the total annual exhaust emission CO2,totof the energy hub system: minCO2,tot=CO2,e+CO2,f(3) Where, CO2,eis the exhaust emission of an electrical device, CO2,fis the exhaust emission of a natural gas device, and CO2,totis provided by the lower-layer model. The heat pump capacity constraint of the upper-layer model is: 0≤QHP,max≤Q_maxHP,max(4) Where, Q_maxHP,maxis the theoretical maximum capacity of the heat pump, i.e., the desirable upper limit when optimizing the capacity of the heat pump, and is provided by the lower-layer model. Optionally, the step (3) specifically includes that: In the double-layer optimization, the upper layer mainly optimizes the capacity of the heat pump, and the lower layer mainly optimizes the power of various sets of equipment. The first objective function of the lower-layer model is to minimize the total annual operation cost Copof the energy hub system: minCop=Cop,e+Cop,f(5) minCop,e={φe,night∑t=1NPe(t)Δt,t∈[19,24)φe,day∑t=1NPe(t)Δt,t∈[0,19)(6)Cop,f=φf∑t=1NPf(t)Δt(7)Pe=Pe,EH+Pe,HP+Pe,CH+Le(8) Where, Cop,eis the total annual operation cost of electricity, Cop,fis the total annual operation cost of natural gas, φf=0.316 is the price per unit natural gas, φe,night=0.4 yuan/kwh is the price per kilowatt-hour in an off-peak period of electricity consumption [19:00 to 24:00), φe,day=0.6 yuan/kwh is the price per kilowatt-hour in a peak period of electricity consumption [00:00 to 19:00], Pf(t) is the total power of natural gas equipment at time t, Pe(t) is the total power of electrical equipment at time t, Δ t=1 is unit time, N=8760 is the total times of a year, Peis the total electric power, Pe,EHis the power of the electric boiler, Pe,HPis the power of the heat pump, Pe,CHis the power of a refrigerator, and Le=1000 kw is additional electric power of a user. The second objective function of the lower-layer model is to minimize the total annual exhaust emission CO2,totof the energy hub system: minCO2,tot=CO2,e+CO2,f(9) CO2,e=λeΣt=1NPe(t) Δt(10) CO2,f=λfΣt=1NPf(t) ≢t(11) Where, the CO2,eis the total annual exhaust emission of electricity, CO2,fis the total annual exhaust emission of natural gas, λe=0.02072 kg/kwh is the exhaust emission per unit electric power, and λf=0.17644 kg/kwh is the exhaust emission per unit natural gas. The load balance constraint of the lower-layer model is: originalconstraint:st.{Lh=ηfhBhPf+ηehEHPe,EH+ηehHPPe,HP(12)Lc=ηecCHPe,CH+(ηehHP-1)Pe,HP(13)looseconstraint:st.{Lh≤ηfhBhPf+ηehEHPe,EH+ηehHPPe,HP(16)Lc≤ηecCHPe,CH+(ηchHP-1)Pe,HP(17)CV.{g1=max(0,1-(ηfBhPfh+ηehEHPe,EH+ηehHPPe,HP)/Lh)(18)g2=max(0,1-(ηecCHPe,CH+(ηchHP-1)Pe,HP)/Lc)(19)Lh=Ah+Ahsin(2πtτy+π2)(20)Lc=Ac+Acsin(2πtτy-π2)(21) Where, Ah=6000 kw is the amplitude of a heating load function, and Ac=6000 kw is the amplitude of a cooling load function. Where, Lhis total heating load, Lcis total cooling load, ηfhB=0.85 is a heating coefficient of the natural gas boiler, which represents the heating capacity per unit natural gas in the natural gas boiler, ηehEH=0.95 is a heating coefficient of the electric boiler, which represents the heating capacity per kilowatt-hour electricity in the electric boiler, ηehHP=6 is a heating coefficient of the heat pump, which represents the heating capacity per kilowatt-hour electricity in the heat pump, and ηecCH=4 is a refrigerating coefficient of the refrigerator, which represents the refrigerating capacity per kilowatt-hour electricity in the refrigerator. The energy source equipment operation constraint of the lower-layer model is: st.{Pe,CH≥0(22)Pe,HP≥0(23)Pe,EH≥0(24)Pf≥0(25)st.{ηecCHPe,CH≤QCH,max(26)(ηehHP-1)Pe,HP≤QHP,max(27)ηehEHPe,EH≤QEH,max(28)ηfhBPf≤QB,max(29)lossfunction:g3=max(0,1-QHP,max/(ηehHP-1)Pe,HP)(30)Pe,HP(t)≤min{Lc(t)ηehHP-1,Lh(t)ηehHP}(31) Where, QCH,max→∞ is the maximum capacity of the refrigerator, QEH,max=2000 is the maximum capacity of the electric boiler, and QB,max♯∞ is the maximum capacity of the natural gas boiler. Based on the working principle of the heat pump, the heat pump can heat and refrigerate simultaneously, and the heating capacity is equal to the refrigerating capacity, so in order not to waste energy, the maximum power of the heat pump does not exceed min{Lc(t)ηehHP-1,Lh(t)ηehHP}. Optionally, the step (4) specifically includes that: (4-1) The binary search algorithm is a computer algorithm with the time complexity of O(logn). A lower limit and an upper limit of the capacity of the heat pump need to be set according to the idea of the binary search algorithm. It can be known from the formula (27) that the value range of the capacity of the heat pump is [lmid,rmid]=[0, (ηehHP−1)Pe,HP]. (4-2) An ending condition of binary search needs to be set according to the idea of a binary algorithm. According to the idea of the multi-objective algorithm, if the length of the value range of the capacity of the heat pump is less than L, then the binary search is ended to enter step (4-7). (4-3) According to the analysis of a heat pump efficiency graph, large or small heat pump capacity is not beneficial to the operation of the whole energy hub. The heat pump efficiency graph which is a quadratic function with an upward opening is obtained. So, we need to take three values for comparing each time when binary search is performed, respectively: mid=(lmid+rmid)/2 (32) lmid=(lmid+mid)/2 (33) rmid=(mid+rmid)/2 (34) (4-4) Optimal total annual operation cost lmidCop, midCop, and rmidCopand optimal total annual exhaust emission lmidCo2tot, midCo2tot, and rmidCo2totcorresponding to the lmid, mid, and rmid are obtained from the lower-layer model, and objective function values, total annual cost Ctotand total annual exhaust emission Co2tot, are calculated by means of objective function formulae (1) and (3), which are respectively: tuplelmid=(lmidCtot, lmidCo2tot) (35) tuplemid=(midCop, midCo2tot) (36) tuplermid=(rmidCop, rmidCo2tot) (37) (4-5) If tuplelmiddominates tuplermid, then the heat pump range is updated to be [lmid, mid], and step (4-2) is re-executed. Otherwise, step (4-6) is executed. (4-6) If tuplermiddominates tuplelmid,then the heat pump range is updated to be [lmid, mid], and step (4-2) is re-executed. Otherwise, the tuplermidand the tuplelmiddo not dominate each other, then step (4-7) is executed. (4-7) Optimization solutions, tuplelmid, tuplemid, and tuplermid, are obtained. The optimization solutions are selected and output according to preference. Optionally, the step (5) specifically includes: (5-1) Heat pump capacity, lmid, mid, and rmid, are obtained from the upper-layer model; the capacity of each heat pump is optimized by operating the lower-layer model, and optimized results are transmitted to the upper-layer model, where t=1 needs to be set every time. (5-2) Algorithm parameters are set corresponding to time t, and gene coding is performed on decision variables, where the used real number encoding manners respectively include: Pe,CH, Pe,HP, P4,EH, Pf. (5-3) A population P is initialized. (5-4) Objective function values, operation cost Cop,tand exhaust emission Co2,tat time t are calculated. (5-5) Crowding distance between individuals in the population P is calculated. (5-6) Selection operation is performed by using a binary tournament selection method. Where, in the binary tournament selection method, a tournament selection strategy is that two individuals are taken out from a population (put back for sampling), and then a better one is selected to enter an offspring population. The operation is repeated until a new population scale reaches the original population scale. (5-7) Crossover operation is performed by using a simulated binary crossover operator (SBX). Step (5-7) specifically includes: x1,jt+1=0.5*[(1+rj)*x1,jt+(1-rj)*x2,jt](38)x2,jt+1=0.5*[(1-rj)*x1,jt+(1+rj)*x2,jt](39)rj={(2uj)1η+1ifuj≤0.512(1-uj)1η+1othersituations(40) Where, uj∈ U(0,1), η=1 is a distribution index. (5-8) Mutation operation is performed by using a polynomial mutation operator PM. Step (5-8) specifically includes: x1,jt+1=x1,jt+Δj(41)Δj={(2uj)1η+1-1ifuj≤0.51-(2(1-uj))1η+1othersituations(42) Where, uj∈ U(0,1), η=1 is a distribution index. (5-9) A parent population P and an offspring population Q are merged into a population R; the population R is sorted according to a constraint violation degree and a non-dominant relationship; the former N individuals of the ranked population are selected to enter the next generation for evolution, where N is the size of the population. Step (5-9) specifically includes: CV=g1+g2+g3(43) The constraints (22), (23), (24), (25), (26), (28), and (29) are ensured to be strictly followed during initialization and evolution. Loss functions, g1, g2, and g3, are calculated according to the formulae (18), (19), and (30), and the constraint violation degree is obtained through a formula (43). The individuals with the constraint violation degree of 0 are selected to enter the population P. If the population P is full, then crossover and mutation are started to be selected; otherwise, if the population P is not full, the individuals with low constraint violation degrees are selected. Front individuals in a non-dominated sorting layer are selected when the constraint violation degrees are the same, and the individuals with large crowing distance are selected when non-dominated sorting layers are the same. (5-10) Whether an algorithm ending condition is satisfied is determined, which specifically includes: the solutions at the time t are stored when continuous N generations of objective function values are converged to a small interval or reaches the maximum number of evolutionary iterations, including the objective function values and decision variables: Cop(t), CO2(t), Pe,EH(t), Pe,HP(t), Pe,CH(t), Pf(t). Step (5-11) is executed; otherwise, step (5-4) is re-executed. (5-11) Whether the solutions at k typical times have been solved or not is determined, which specifically includes that: There are 8760 times in a year, and it can be known from a load function curve that the annual load demands are symmetrical, so the solutions of 4380 times need to be solved. In order to improve the optimization efficiency, the present disclosure only optimizes the solutions of k typical times by using the idea of typical times. If the solutions at k typical times have been solved, step (5-12) is executed, and otherwise, step (5-2) is re-executed. (5-12) The solutions of non-typical times are approached by using a linear fitting method. Step (5-12) specifically includes that: There are many linear fitting methods, where a Lagrange interpolation method and a cubic spline curve are commonly used. The present disclosure approaches the solutions of non-typical times by using the Lagrange interpolation method. Lagrange interpolation is performed between every two typical times to obtain the solutions of all non-typical times. Finally, the solutions of the typical times and the non-typical times are merged. (5-13) Optimal total annual operation cost Copand optimal total annual exhaust emission CO2,totare calculated. Cop=k*ΣCop,t=k*Σ(φfPf(t)+φe,energyPe(t) (44) is obtained according to the formulae (5), (6), (7), and (8). CO2,tot=k*∈(λePe(t)+λfPf(t)) (45) Pe(t)=(Pe,EH(t)+Pe,HP(t)+Pe,CH(t)+Le) (46) are obtained according to the formulae (9), (10), and (11). (5-14) Annual operation plans, optimal total annual operation cost, lmidCop, midCop, rmidCop, and optimal total annual exhaust emission lmidCo2totmidCo2tot, and rmidCo2totof various sets of energy source equipment in the energy hub corresponding to lmid, mid, and rmid can be obtained according to the statistics of the power information and Cop, CO2,totof various sets of energy source equipment of all times. The information is transmitted to the upper-layer model as parameters for subsequent optimization. Optionally, step (6) specifically includes: The integrating double layers of optimization models is to transmit the solutions optimized by the lower-layer model to the upper-layer model, and parameters need to be obtained from the lower-layer model continually when the upper-layer model is optimized. The optimal solutions obtained after the optimization of the upper-layer model is ended are the optimal solutions of problems. The present disclosure discloses an optimization method for capacity of a heat pump and various power of various sets of energy source equipment in an energy hub, which can solve the problem of multi-objective double-layer model without the help of commercial optimization software. A reasonable, efficient, and green planning solution is obtained, so that the total operation cost and the total exhaust emission of the energy hub reach optimal relatively. In this specification, specific examples are used to describe the principle and implementation manners of the present disclosure. The description of the embodiments above is merely intended to help understand the method and core idea of the present disclosure. In addition, those skilled in the art may make modifications based on the idea of the present disclosure with respect to the specific implementation manners and the application scope. In conclusion, the content of the present description shall not be construed as a limitation to the present disclosure. Any other modifications, ornaments, replacements, combinations, and simplifications made under the ideas and principles of the present disclosure should be equivalent replacements, and should be included within the scope of protection of the present disclosure. | 17,266 |
11862974 | Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the inventive concepts presented herein. DETAILED DESCRIPTION As described herein, a grid distribution system aggregates energy resources of multiple distributed energy resources (DERs) and provides service to one or more energy markets with the DERs as a single market resource. The DERs can create data to indicate realtime local demand and local energy capacity of the DERs. Based on DER information and realtime market information, the system can compute how to provide one or more services to the power grid based on an aggregation of DER energy capacity. Power is delivered in a grid system as alternating current (AC) power, which involves sinusoidal current and voltage waveforms, which can be thought of as alternately pushing electricity and then pulling electricity in a periodic cycle. AC energy's capacity to flow in reverse directions and be modulated up or down in realtime by operator-monitored transformers enables its transmission across power lines at high voltage with minimum electric line losses due to heat. AC energy requires continuous, well-balanced control between real power and reactive power as it travels “downstream” from transmission lines, to substation and power lines, and eventually, to the end-user. Power delivered by the grid generally consists of a real power component and a reactive power component. Real power is measured in Watts, and refers to the active energy that does electrical work. Real power is delivered when the voltage waveform and current waveform are perfectly aligned in-phase. For efficient real power delivery, the timing of the demand for the active energy waveforms should match the timing of the delivery of the energy waveforms on the grid. When the timings are not aligned, there is power loss in the transfer of energy. Reactive power is measured in VARs (volt-amperes reactive), and refers to energy that ensures the two timings align, and therefore reduces power loss. Reactive power can be leading or lagging relative to the real power, based on the phase difference between the current and voltage waveforms. Power as seen by a consumer can be understood differently from the energy itself provided to calculate the power. Power is typically represented by W dot h or Watt-hours. Multiplying the Watt-hours by the rate charged by the utility provides the dollar amount owed by the consumer to the utility. But energy can be represented in different ways, and can be measured in multiple different ways. Examples include (VA) or V dot I (voltage vector multiplied by current vector for volt-amps), V dot I dot PF (voltage vector multiplied by current vector times the power factor for Watts), and the square root of W{circumflex over ( )}2 (square root of Watts squared for volt-amps-reactive). The consumer typically sees the power in Watt-hours which gives the cost of the energy delivered to the premises. Utilities have also started to measure and charge for reactive power consumption at the user premises. There has been a significant increase in grid consumers adding renewable sources locally at the consumer locale to produce power. The renewable energy sources tend to be solar power or wind power or a combination, with a very significant number of solar systems being added. One limitation to customer power sources is that they tend to produce power at the same time, they produce only real power, and may cause real power to be pushed or exported back onto the grid (an upward injection of watts). The grid infrastructure is traditionally a one-way system, and the real power pushed back from the customer premises toward the central management and the central power source can create issues of grid voltage control and reactive power instability on the grid. These issues have caused grid operators to limit the amount of renewable energy that can be connected to the grid in some areas. In some cases, additional hardware or grid infrastructure is required at or near the consumer to control the flow of power back onto the grid. In addition to the issues caused by renewable sources, the increase in use of air conditioning units and other loads that draw heavily on reactive power create additional strain for the grid management to keep grid voltages at regulated levels. Increased use of air conditioning has resulted in rolling brownouts and blackouts. Other times there are temporary interruptions on the grid as equipment interfaces are reset to deal with the changes in load when people return home from work and increase power consumption there. Traditionally, the central management must maintain compliance of grid regulations (such as voltage levels). Whenever something connected to the grid enters an overvoltage scenario, it shuts off from the grid, which can then create additional load on surrounding areas, resulting in larger areas of the grid coming down before the central management can restore grid stability. In contrast to the traditional centralized management of the grid, an intelligent grid operating system (iGOS) provides the ability to distribute intelligence throughout the grid. In particular, iGOS can enable the interface with the grid at the point of consumption, such as behind the meter. In one embodiment, the iGOS enables an Aggregated Distributed Energy Resource (ADER) grid. An ADER grid provides virtual and modular components, with communication to offer the full complement of traditional power resources at any point in the system at any time. Grid operators benefit from greater control and oversight, such as being able to directly manage distributed energy generation the same as with traditional generators, which increases energy distribution efficiency. Increased look-ahead forecasting allows better economic modeling. Additionally, by providing energy management at the point of consumption, the ADER grid is much more stable relative to a traditional grid. With the ADER grid, the DERs can generate the reactive power needed to increase grid reliability and stability. The generation of the energy by the DER can be managed in a way to provide services to the grid, instead of ignorantly pushing real power back upstream. In one embodiment, iGOS includes an automatic self-sufficient system that manages realtime data from sensing equipment, realtime data feeds, and measurements of generating resources (renewable, storage, generators, and more), with algorithmic computational devices to collect and analyze the realtime data. Based on the computations, the system can adjust its local operation and inject energy back in a specific proportion in amounts and time with real and reactive power. In one embodiment the iGOS system enables the realtime execution of dispatch and control through secure communication lines. The ADER grid can be enabled by DERs that implement iGOS in addition to an aggregating control center that also implements iGOS. The DERs can dynamic, on demand, generate any combination of real and reactive power on a device-by-device basis. The generation of the reactive power does not come at the expense of the generation of real power, and thus, the system can provide exactly the type of energy needed at the consumer as well as presenting the best interface to the grid for efficient transfer. It will be understood that traditional systems perform power factor correction to adjust a power factor to improve the interface with the grid. However, traditional power factor correction requires routing all power through a load of capacitors or inductors or both to attempt to consume the imbalanced reactive energy to restore the power factor. Such systems only operate by pushing power through an additional load at additional loss of power. In contrast to traditional power factor correction, the DERs described herein can sit in parallel to a node where the energy flows, but instead of passing all power through an additional load, the DERs generate the proportional in timing and amount of real and reactive power needed to bring the voltage and current waveforms back to a desired alignment or desired offset. Such operation may be referred to as reactive power injection. Instead of setting up a reactive power load proportional to the real power load drawn to influence power factor, reactive power injection refers to injecting VARs into the point of common connection to adjust the effective impedance looking into the node. Such capability enables adapting the operation of the grid to evolving energy needs, working with the established infrastructure, and without necessitating an overhaul of the system. In one embodiment, the iGOS can manage energy, capacity, and ancillary services in realtime. Grids are normally designed to be deterministic, where the determinism of available capacity and load demand prediction can inform the financial models needed to operate the grid. Such financial models include the pricing and operation of grid energy distribution. In addition to the load on the infrastructure, traditional renewables at the consumer end disrupt the determinism of the grid operation and management. The grid markets are designed to maintain stability through energy trading and distribution. However, there are certain cases where determinism is more highly valued than stability. The application of iGOS allows a grid to operate deterministically while also providing stability. The iGOS platform enables intelligent control individually at each node of a network of DERs, as well as aggregation for overall network stability. In one embodiment, the iGOS platform includes nodes with sensors and information sources to make operating decisions based on forecasting, price signals, or other information, or a combination of information. The nodes provide iGOS management locally, and can provide realtime information in an aggregated node to a control center that can trade the energy on the markets. One or more groups of nodes connects to a substation, and one or more substations connect to a high voltage line. Energy trading occurs at the grid energy source level, which can be managed by an iGOS aggregation platform that can aggregate and market DER energy production based on management and information from the DERs or nodes. FIG.1is a block diagram of a system to manage distributed energy resources of a power grid. System100represents a grid network, with grid120that includes distribution control122to transmit power along transmission lines. Traditionally, distribution control122managed downstream flow of power from one or more power plants140to various customer124. Customers124represent any one or more groups of consumers, which connect at various locations downstream from power plant140. In one embodiment, at least certain customers124can be referred to as “prosumers,” which are consumers who locally produce power. Traditional local power production in DERs can include power production with “generators,” “backup generators,” “renewable energy sources,” or “on-site power systems.” DERs refer to small-scale energy sources built close to homes or businesses where electricity is consumed. So-called “green power technologies such as solar or photovoltaic (PV) systems (where PV-cell flat panes mounted on rooftops convert sunlight into electricity), or wind systems (where turbines with fan blades positioned atop towers use wind to generate electricity) are among the most popular. Expansion of traditional DERs among customer124can put strain on grid120through the unintelligent injection of watts into the grid. The injection of watts cannot be controlled in realtime like the flow of AC energy. The utilities tends to spread the costs associated with increased VAR requirements due to the injection of watts. In one embodiment, at least some of customers124include smart DERs130. Control center110manages nodes132to aggregate and present the combined capabilities as a single energy resource available on one or more energy markets. It will be understood that nodes132represent DER nodes that each have local energy generation resources. In one embodiment, control center110includes local power112, which can be more like a “traditional” power plant, but with a smaller output capacity. In one embodiment, local power112can provide a base level of power available to aggregate with power from nodes132to trade on the energy market. Trading on the energy market refers to making a bid or an offer for services for one or more different types of energy services required by the grid, such as real power capacity, ancillary services such as voltage or reactive power support, demand/response services, or other services, or a combination. In one embodiment, control center110couples to grid120via PCC (point of common coupling or point of common connection)126. PCC126can represent multiple different connection points, such as connection points for different DER nodes132. Collectively, control center110can provide energy services to grid120via DERs130. In one embodiment, each node132executes iGOS. In one embodiment, control center110executes iGOS. In one embodiment, control center110executes a trading platform. DER nodes132include intelligence to provide realtime control of one or more microinverters or gateway devices, or a combination, which can monitor, analyze, control, aggregate, and predict the watt contributions of DER systems while simultaneously modulating the release of VARs. The monitoring of watts and VARs can provide optimum energy efficiency, which will maximize the consumer's cost-savings while also stabilizing the operations of grid120. In one embodiment, DERs130include an iGOS intelligent platform that leverages realtime telemetry or simultaneous measurements of watt and VARS output to transform a consumer's DER system into a virtual spinning generator. It will be understood that for a DER system to be a virtual spinning generator, the DER needs to do more than simply monitor realtime data, but to analyze and be able to adjust operation in realtime to affect its output operation in response to either the realtime data or external commands from control center110or grid120, or a combination of realtime data and external commands. The DERs as virtual generators can then be deployed via dispatch or local autonomous control to inject accurate amounts of VARs to stabilize grid120. In one embodiment, DERs130or control center110or both perform active modeling to “learn” behavior by recognize past patterns of usage, which can further enable behind-the-meter stabilization to occur independently of utility operators. In one embodiment, each node132includes an intelligent platform that reacts to demand-response situations. A demand-response situation is one where end-users are provided with financial incentives to curtail energy use. In one embodiment, nodes132can signal the local DER system (such as through local generation and storage capabilities) to increase an output of watts to compensate for the energy that would usually derive from grid120. With an appropriate real and reactive power response, the consumer can benefit from cost-savings resulting from use of DER power, as well as receiving a financial reward offered by the utility for decrease of energy loads. In one embodiment, the iGOS system or intelligent platform as operational in DERs130or control center110or both, can provide analytical aggregation of information. For example, system100can collect information related to daily, weekly, weekend, monthly, or seasonal usages, or a combination. In one embodiment, a node132can learn the energy signature and energy behaviors of various appliance loads such as refrigerators, lighting, or others, or a combination. In one embodiment, DER nodes132include secure connection to control center110, or some entity of grid120, or both. The secure connection can include encrypted, firewall-supported channels a network of utility companies or other markets in which the energy resource may participate. For communication, DERs130and control center110include communication hardware, such as routers, hardware network interfaces, network protocol stacks, drivers, software applications, or other components, or a combination. Through the communication links the DERs can provide realtime data to control center110, which can then aggregate information from multiple DERs to bid on the energy markets. FIG.2is a block diagram of an embodiment of a control center to manage distributed energy resources of a power grid. System200provides a representation of a control center that can include an energy trading desk or energy trading platform. Control center210represents a control center in accordance with any embodiment described herein. Control center210includes hardware elements to function, such as network interface212and processor214. Network interface212represents one or more network interface devices or circuits to interconnect with DERs260, and other sources of information, such as realtime market information. Control center210can receive information from DERs and provide commands to them through network interface212. Processor214represents one or more processing resources, and can be or include CPUs, servers, computers, or other computing resources. Processor214enables control center210to perform calculations to determine how to use realtime data and energy resources of DERs260. While not explicitly shown, in one embodiment, processor214executes iGOS or an intelligent computation and control platform. While not specifically illustrated, control center210includes memory or storage or a combination to store data for use and for computations. With the hardware resources, control center210can execute trading platform or trading desk216. In one embodiment, trading platform216includes one or more software programs or software agents that processor214executes to perform trading functionality. Trading platform216enables control center210to determine what market demand is, aggregate and compute an ability to service at least part of the demand, and make a bid to provide the services. Trading platform216allows the aggregation and presentation of some of all of DERs260as a single service provider to provide the service. In one embodiment, system200includes power station250, which can represent energy generation resources local to control center210, and are energy generation resources in addition to those of DERs260. In one embodiment, control center210aggregates and presents energy resources for bidding on an energy market, including those of power station250. Control center210can provide energy distribution or other distributed energy resource management for DERs260based on information from, or to provide service to, one or more of IPP222, ISO224, RTO226, IOU228, or rate payers230, or a combination. IPP (independent power producer)222represents other generators or participants in the energy market. ISO (independent system operator)224represents entities that control and manage grid distribution or transmission resources. ISO224generally represents the energy markets as the entities that accept bids from power producers. RTO (regional transmission operator)226refers to regional transmission controllers such as transformers and substations. IOU (investment owned utility)228represents utility operators. Rate payers230represent the regulators and organizations that set standards for the utility. Control center210can provide any one or all of the following services: forecasting232, realtime (edge) energy market services234, capacity236, ancillary services238, or demand response240, or a combination. Forecasting232represents an ability to participate in markets that look ahead by weeks or days, and commit to providing energy services. Realtime (edge) energy markets234represent short term markets, such as 15 minute markets, and bid services out to such markets. Capacity236can provide or absorb energy to average out operation of the grid. Ancillary services238represents support services to manage, for example, the voltage and power factor of the grid. Demand/response240represents an ability to either reduce energy usage, or increase energy output to reduce an amount of energy demanded of the grid. Other services are possible. DER aggregation is becoming more common. Recent regulations by FERC (Federal Energy Regulation Committee) permits the aggregation and trading of energy from DERs in CAISO (California Independent System Operator) territories. It is anticipated that other markets will follow. With such regulations, aggregation of multiple iGOS nodes provides valuable services to the grid, which can also benefit the system owners for DERs that are capable of aggregation. With the technologies provided herein, rather than creating a stress on the grid, the DERs for renewable energy resources become important market participants to achieve the stability and reliability needed from the power grid. It also opens the energy market to participation by smaller systems that would otherwise likely have to curtail valuable energy generated. While certain examples are provided, it will be understood in general that there is a great deal of interdependent regulatory, infrastructural, and economic planning and preparation that continually go into ensuring that the lights turn on when we flip the switch. The grid already has huge energy generators, transformer towers, and power lines that provide an immense amount of power. With iGOS, rather than having to continue to build that infrastructure out to meet peak demand that is only short-lived, DERs can drop the overall big-scale infrastructure needs by aggregation of small resources. The markets are controlled by laws and regulation, which govern the transmission and distribution of power by utilities. Market participants regularly and simultaneously negotiate “day-ahead” and “peak” prices in multiple markets across the country. These are the day-ahead and spot markets. The day-ahead market conducts sales and purchases of wholesale electricity at a fixed price to meet the forecasted load or demand for the following operating day. Spot markets are held to meet peak energy demands in excess of a given day's forecasted load. Despite this immense system that is in place, prior to the deployment of renewables, for most everyday consumers of electrical energy, the utility companies that send the bill represent the entire grid system. The intelligent platforms described herein enable the continuation of the decentralization that has already begun with renewable adoption. Electrical energy as a commodity is now frequently bought and resold in transactions known as “sales for resale” across utility companies and other retail marketers a number of times between the moment of production and the moment of consumption by end-users. With system200, DERs can participate in that market. System200not only enables participation of DERs260in the energy markets, it really provides a smarter smart grid by distributing intelligence. With participation by DERs260, the energy can be generated and managed for realtime markets and services at the load where it is needed most. In one embodiment, each DER260performs monitoring, protection, and optimization through multiple sensors fed it into multiple algorithms. In one embodiment, information from the realtime market is fed it into algorithms to issue signals for dispatch of energy resources to keep the balance at multiple levels (load, substation, energy transport, demand/respond, time of day, energy to storage, energy from storage, energy to load from solar, energy to load from storage, energy from renewables, or others, or a combination). In one embodiment, control center210and trading platform216can aggregate from a plurality of available DERs260. Thus, control center210may send commands to selected ones of DERs260for services to provide services for an energy market. In one embodiment, control center210attempts to maximize the availability of services, and aggregates from all DERs possible or available for contributing. In response to control signals or commands, the DERs can change operation to provide the services on the grid. In one embodiment, the DERs provide energy for local customers. In one embodiment, iGOS can determine that it is more cost effective to provide a service on an energy market, and purchase power from the grid for a local customer. Thus, in one embodiment, the system provides services to the grid for an energy market, while continuing to service a local customer. In one embodiment, the system provides power to the local customer from the grid, or at least partially from the grid, and uses some or all energy resources to provide a service to an energy market. In one embodiment, trading platform216computes whether a bid can be made to meet demand in a market, based on availability of DERs260and energy resources from the DERs. FIG.3is a block diagram of an embodiment of a distributed grid system. System300includes a grid network, and can be one example of a grid network or system in accordance with an embodiment of system100. System300may be only a segment or portion of one of the previously-described systems. In one embodiment, system300is a grid network that operates without central grid management. In one embodiment, system300is a grid network that operates without a central power plant or other large-scale power source that provides power to the entire grid. In one embodiment, system300is a virtual grid or a modular grid. In one embodiment, system300is a virtual grid that can connect to a traditional grid as an independent segment. In one embodiment, system300can connect to other virtual grid or modular grid segments. System300illustrates neighborhood340and neighborhood360, which represent sub-portions of the grid that can have any number of consumers that do and do not include local energy sources, and can include any number of consumers that do and do not include local control nodes. Neighborhood340couples to control node332. Similarly, neighborhood couples to control node334. Control nodes332and334manage DERs. In one embodiment, a control node can manage multiple DERs. Control nodes332and334are coupled to each other by some infrastructure, which may be the same as a grid infrastructure, or may simply be a power line having sufficient capacity to enable the control nodes to couple to each other and provide electrical support to each other. In one embodiment, control node332can be PCC322and control node334can be PCC324. In one embodiment, control nodes332and334are coupled to control center310, which can aggregate information about the operation of multiple distributed nodes within the grid network of system300. In one embodiment, control center310includes processing and analysis engines that can determine what operation each node should take in response to grid conditions. In one embodiment, control center310is similar to central grid management, but it can be simpler. Whereas central grid management typically controls interconnection or interface of a central power plant to the grid and potentially the operation of a substation, data center can provide information to distributed nodes. The distributed nodes can independently operate within their segment of the grid network to respond to grid conditions. In one embodiment, control center310provides dispatch information to the distributed control nodes. In one embodiment, neighborhood340includes one or more consumers342that do not have local energy sources. In one embodiment, neighborhood340includes one or more consumers350that include local energy source352and DER node354. The energy source and DER node can be in accordance with any embodiment referred to herein. In general, neighborhood340has a total load that represents the power demand within the neighborhood, and a total capacity that represents the power generation within the neighborhood. The load minus the capacity can represent the net power demand, which can be positive or negative. A negative power demand can indicate that neighborhood340generates more energy than will be consumed by its local consumers. It will be understood that power demand fluctuates throughout the day and year as consumers use and generate different amounts of power. Control node332can continuously monitor the net power demand for its associated neighborhood340. In one embodiment, neighborhood360includes one or more consumers362that do not have local energy sources, and one or more consumers370that include local energy source372and DER node374. The description of neighborhood340can apply equally well to neighborhood360. Neighborhood360also has a total load that represents the power demand within the neighborhood, and a total capacity that represents the power generation within the neighborhood, which can be completely different from those of neighborhood340. In one embodiment, either or both of the neighborhoods can include local energy storage. For example, neighborhood340is illustrated with energy store344, and neighborhood360is illustrated with energy store364. In one embodiment, at least one neighborhood does not include energy storage. In one embodiment, all neighborhoods include energy storage. Energy store344and364represent any type of energy storage that can exist within the neighborhoods. Energy store344and364can represent a sum of all local energy storage resources of individual consumers within the neighborhood. In one embodiment, one or more neighborhood includes a neighborhood energy store. The neighborhood energy store can be in addition to or as an alternative to local energy storage at the individual consumers. In one embodiment, energy store344and364can include battery resources, which can include any type of battery. A battery is a device that stores energy via chemical or electrical means or a combination, and the energy can later be accessed. However, energy storage is not limited to batteries. For example, in one embodiment, an energy store, either local to one consumer or shared among multiple consumers or the entire neighborhood, includes a mechanism to perform work to convert active energy into potential energy, which can then later be recovered via conversion back from potential energy to active energy. For example, consider a water storage system as an energy store. When excess capacity exists within a consume and/or within the neighborhood, the system can trigger a pump to operate on the excess power to pump water “uphill,” essentially in any manner to pump against gravity. Recovery of the energy can include allowing the water to flow back downhill with gravity to turn a generator or mini-generator to generate energy. Another alternative can be to use energy to compress air, and then run a generator with the air as it is decompressed. It will be understood that other examples could also be used where energy storage is not limited to traditional battery resources. In one embodiment, system300is a segment of a grid that includes distributed control. In such a scenario, each node within a grid network hierarchy can manage its own conditions at its PCC for compliance with standards or expectations of performance. In one embodiment, each node can also provide electrical support to neighboring segments or PCCs as it sees conditions at the grid network side (upstream from its segment) fall in performance. In one embodiment, each node can provide electrical support to neighboring segments or PCCs in response to receiving information from control center310, from other nodes, or dispatch or control information from a central management. In one embodiment, system300includes one or more power sources312coupled to provide power to the grid network. One or more power sources312can be in addition to local energy sources at consumers. In one embodiment, no single power source312has sufficient capacity to meet consumer power demands. For example, rather than an industrial or utility-scale power plant, one or more power sources312can be included local to a segment of the grid. The segment can be within a neighborhood or shared among multiple neighborhoods. Power sources312can include smaller scale generators that would be smaller than a full utility implementation, but larger than what would typically be used at a consumer or customer premises. Neighborhood-based power sources312can be directly associated with DER nodes (for example, power source312can be coupled to and controlled by DER devices of node332). The control node can manage the output of the power source. In one embodiment, power source312enables control center310to trade energy as an aggregation of DERs for system300. Without a large-scale power plant, or in addition to such a power plant, and with smaller-scale energy generation (e.g., a neighborhood generator, a neighborhood solar installation, a small-scale hydro-electric generator, or other power sources), a grid network can be installed with reduced infrastructure compared to today's grids. Such a modular grid network can enable the building out of a grid based on current needs and then interconnecting to other independent grid network segments. Each segment can continue to operate independently, but can then benefit from being able to better distribute power generation and power demand based on availability to and from neighboring segments. Each interface or interconnection can include one or more control nodes, which can include one or more power converters each, to control the use of power and the presentation of power upstream. Thus, a local grid network can be built, and then later coupled with another local grid network as another layer of grid network hierarchy is added to interface the two independent segments. In one embodiment, consider that neighborhood340has multiple customer premises350that have local energy sources352. Traditionally grids are designed and built to be unidirectional, as they are designed to deliver power from a single large-scale power plant to the consumers. With power generation at customer premises350, neighborhood340and up through a connected grid can effectively become a bidirectional system where power can be delivered from the central power source to the consumers, but then the consumers can also generate excess capacity that is placed back out onto the grid. If the power generation for the neighborhood and neighboring neighborhoods exceeds instant power demand, the generated power will be pushed back up the grid toward to the power plant. Such a condition can challenge the grid infrastructure. Grid operators (e.g., utilities) typically set limits on how much local power generation can be coupled to the grid, to reduce the risk of a scenario where significant amounts of energy get pushed back up the grid to the power plant. Such a limit is often referred to as saturation, where there is a threshold amount of capacity that is permitted to be attached to the grid. If the saturation threshold has been reached, a consumer typically has to pay for additional grid infrastructure (additional equipment) that will enable the utility to selectively disconnect the consumer's power generation from the grid. Such scenarios also put consumers and utilities at odds with each other, as the consumer does not get to see the same levels of cost reduction because the power generation cannot be used by the grid, and so the grid operator does not pay the consumer for it. In one embodiment, system300can provide an alternative mechanism to deal with grid saturation. In one embodiment, the distributed control in system300can provide dynamic control over power demand and power generation as seen at a PCC and/or as seen at a customer premises or anywhere downstream from a control node. In one embodiment, the control node includes a power converter to control real and reactive power demand and real and reactive power generation. More specifically, the control node can adjust operation to affect a real power component of power as seen downstream from the PCC, and a real power component as seen upstream from the PCC. The control node can adjust operation to affect a reactive power component of power as seen downstream from the PCC, and a reactive power component as seen upstream from the PCC. In one embodiment, the control node can include one or more inverters or one or more microinverters as power converters to apply control over demand and generation. In one embodiment, node332includes a grid connector to connect upstream in a grid network. The grid connector can include known connectors and high voltage and low voltage signal lines. Node332is or connects to a PCC (PCC322) for the grid network segment of neighborhood340. Node332includes control logic, such as a controller or microprocessor or other logic to determine how to operate. In one embodiment, node332determines that a saturation threshold has been reached within neighborhood340. Such a determination can be a result of dynamic monitoring to determine that power generation exceeds power demand. Such a determination can be in response to a notification from a data center or central grid management. Such a determination can be in response to data from other distributed control nodes. In one embodiment, each energy source352in neighborhood340is associated with a control node354within the neighborhood. In one embodiment, each control node354is configured with information about the capacity of its associated energy source352. In one embodiment, each local control node354registers with control node332, which can allow node332to know a total capacity for neighborhood340. In one embodiment, node332knows a total peak real power demand for neighborhood340, such as by configuration or dynamic identification via communication with meters or other equipment distributed at the consumers. In one embodiment, there is a threshold percentage of the total peak real power demand that identifies a value of real power, and when real power generation capacity exceeds the value, neighborhood is considered to be in saturation. In response to the saturation condition, in one embodiment, node332dynamically adjusts operation of power converter(s) to adjust an interface between neighborhood340and the grid. In one embodiment, node332adjusts a ratio of real power to reactive power for neighborhood340as seen from upstream from PCC322(e.g., as seen from PCC324or as seen from central grid management or another part of the grid network). In one embodiment, node332receives dispatch information from data center310or central grid management indicating a level of grid saturation for neighborhood340. In one embodiment, node332receives information from downstream such as a via meters and/or node(s)354indicating levels of grid saturation downstream from PCC322. In one embodiment, node332adjusts at least an amount of real power generation with neighborhood340, such as by communicating to downstream control nodes354to adjust their real power output. In one embodiment, node332can communicate downstream to cause control nodes354to change a ratio of reactive to real power output upstream. In one embodiment, node332adjusts real or reactive power generation or demand or a combination at PCC322to adjust the electrical conditions as seen upstream from PCC322. In one embodiment, node332or node(s)354adjust operation to divert at least a portion of real or reactive power to energy store344. FIG.4Ais a block diagram of an embodiment of an aggregated DER grid. Network410illustrates one example of a distribution grid, which can be an ADER grid. Network410includes multiple nodes412, which can include an iGOS platform as described herein. The ADER grid can provide a homeowner-owned utility, or a consumer-based operational grid. Such a grid can also be referred to as a virtual grid. As illustrated in network410, the distributed resource network can be or include a ring network. Network410couples to transmission line414of a power grid through transformer or substation416. The transformers represent substations or other grid sub-divisions. Transmission line414represents a high-voltage grid transmission or distribution line. FIG.4Bis a block diagram of another embodiment of an aggregated DER grid. Network420illustrates one example of a distribution grid, which can be an ADER grid. Network420includes multiple nodes422, which can include an iGOS platform as described herein. The ADER grid can provide a homeowner-owned utility, or a consumer-based operational grid. Such a grid can also be referred to as a virtual grid. As illustrated in network420, the distributed resource network can be or include a star network with central point428. Network420couples to transmission line424of a power grid through transformer or substation426. The transformers represent substations or other grid sub-divisions. Transmission line424represents a high-voltage grid transmission or distribution line. FIG.4Cis a block diagram of another embodiment of an aggregated DER grid. Network430illustrates one example of a distribution grid, which can be an ADER grid. Network430includes multiple nodes432, which can include an iGOS platform as described herein. The ADER grid can provide a homeowner-owned utility, or a consumer-based operational grid. Such a grid can also be referred to as a virtual grid. As illustrated in network430, the distributed resource network can be or include a combination of a star network and a ring network, with central point438. Network430couples to transmission line434of a power grid through transformer or substation436. The transformers represent substations or other grid sub-divisions. Transmission line434represents a high-voltage grid transmission or distribution line. As seen in the fourth network representation, a substation can be a node in a higher-level substation. Thus, any combination of network organization can be applied. FIG.4Dis a block diagram of another embodiment of an aggregated DER grid. Network440illustrates one example of a distribution grid, which can be an ADER grid. Network440includes multiple nodes442, which can include an iGOS platform as described herein. The ADER grid can provide a homeowner-owned utility, or a consumer-based operational grid. Such a grid can also be referred to as a virtual grid. As illustrated in network440, the distributed resource network can be or include a point to point ring network. Network440couples to transmission line444of a power grid through transformer or substation446. The transformers represent substations or other grid sub-divisions. Transmission line444represents a high-voltage grid transmission or distribution line. In one embodiment, a substation can be a node in a higher-level substation, as illustrated by connection448. Thus, any combination of network organization can be applied. As seen in the fourth network representation, a substation can be a node in a higher-level substation. Thus, any combination of network organization can be applied. FIG.5is a block diagram of an embodiment of a system with monitoring and control of DERs among different neighborhoods. System500represents a distribution environment for a utility grid. System500supports DER aggregation in accordance with any embodiment described herein. System500can be considered one example of an ADER grid. System500illustrates that aggregation of nodes, such as iGOS aggregation, can be implemented in parallel with traditional grid hardware. For example, not all customer premises in a neighborhood need to include DERs for the DER aggregation to work. Grid510represents the grid infrastructure, which can include a central generator or power plant managed by utility502, which can perform central grid management. System500illustrates two neighborhoods,520and540, but it will be understood that any number of neighborhoods can be included in system500. Neighborhoods520and540represent any segment or sub-segment of the grid. Neighborhood520couples to grid510via PCC512, while neighborhood540couples to grid510via PCC514. In one embodiment, neighborhoods520and540could couple to grid510through the same PCC. Neighborhood520includes multiple utility customers522-C,524-C,526-C,528-C,532-C,534-C, and536-C. It will be understood that in a typically system there may be dozens or hundreds of customers in a neighborhood. The customers can be any type of power consumer described herein. In one embodiment, a single consumer includes multiple customer premises. In one embodiment, one customer premises includes multiple consumers. In one embodiment, there is a one-to-one relationship between consumers and customer premises. It will be observed that customers526-C,528-C,532-C, and536-C do not have local energy sources or local power generation. Customers522-C,524-C, and534-C include energy sources522-ES,524-ES, and534-ES, respectively. The energy sources represent local power generation. The customers with energy sources include DER nodes or management nodes or intelligent platforms522-N,524-N, and534-N, respectively. In one embodiment, the DER nodes manage the use of locally generated energy locally, and to manage the output of energy back to neighborhood540and ultimately to grid510. Neighborhood540is also illustrated to include multiple consumers, with customers544-C and548-C, respectively, including energy source544-ES and node544-N, and energy source548-ES and node544-N. Customers542-C and546-C do not include local power generation. The neighborhoods can include any number of consumers that do not include local power generation and any number of consumers that do include local power generation, and any combination. System500does not specifically illustrate a control center for DER aggregation, but it will be understood that the DERs with energy generation sources can be aggregated to provide services to grid510. In one embodiment, DERs from the two different neighborhoods can be aggregated for purposes of providing grid services. In one embodiment, only DERs within the same neighborhood will be aggregated for one or more services provided to an energy market. In one embodiment, for aggregation of DERs from different neighborhoods, the DERs must couple to a common PCC. In one embodiment, there is no such restriction for aggregation DERs from different neighborhoods, and as long as the control center can couple communicatively with the DERs and the DERs can provide the agreed services, then the DERs can be aggregated. In one embodiment, the ability to aggregate across neighborhoods depends on the services provided. FIG.6is a block diagram of an embodiment of a gateway device in a distributed grid system. System600represents one embodiment of a grid system, and can be a grid system in accordance with any embodiment described herein. Grid610represents a utility grid network on which DER aggregation is permitted. Meter620represents a grid meter, or a meter used within the grid to measure and charge for power delivered by the grid. In one embodiment, meter620can be considered part of the grid infrastructure and can be referred to as an entrance meter. In one embodiment, meter620is a four-quadrant meter. Meter634of gateway630is understood to be separate from meter620. In one embodiment, meter620monitors power delivered by grid610to PCC622, which represents a PCC in accordance with any embodiment described herein. In one embodiment, system600includes gateway that can be and/or be part of a control node in accordance with any embodiment herein. In one embodiment, gateway630represents “the brains” of a control node or DER node. In one embodiment, gateway includes router632to enable gateway630to communicate with other devices, such as devices outside of the PCC. In one embodiment, router632enables gateway630to communicate with data center680. Data center680can represent a central data location for a distributed grid network or a control center in accordance with any embodiment described herein. In one embodiment, data center680can provide dispatch information from central grid management. Thus, data center680represents a source of grid-based information, such as control, dispatch information, or other data about grid operation, as well as other aggregation information. In one embodiment, router632includes Ethernet connections or other connections that use Internet protocols. In one embodiment, router632includes grid interconnections. In one embodiment, router632includes proprietary connectors. In one embodiment, router632represents a stack or protocol engine within gateway630to generate and process communication in addition to the hardware connectors that provide an interface or connection to the grid. In one embodiment, gateway630includes meter634, which represents a metering device, and can be four-quadrant meter. Meter634enables gateway630to monitor power demand or power generation or both on the consumer side of PCC622. The consumer side of PCC622is the side opposite the grid. The consumer side is the electrical point of contact to the loads or load control for the consumer. Typically the PCC includes some type of fuse system or other disconnection mechanism. The fuse system can be soft fuses (e.g., switches or other mechanisms that can be electrically opened and closed) or hard fuses that must be mechanically or physically reset or replaced. In one embodiment, gateway634performs aggregation based at least in part on data gathered by meter634. Gateway630includes controller636, which represents hardware processing resources to control the operation of the gateway. Controller636can also represent software or firmware logic to control the operations of gateway630. In one embodiment, controller636can be implemented by more than one hardware component. In one embodiment, controller636includes or is an embedded computer system. For example, controller636can include an embedded PC (personal computer) board and/or other hardware logic. Controller636generally controls the operation of gateway630, such as controlling router632and/or meter634. In one embodiment, if gateway630is said to do something, controller636can be considered to execute operations to perform what is said to be done. In one embodiment, system600includes one or more loads640on the consumer side of PCC622. In one embodiment, system600includes one or more energy sources660. Energy source660represents a power generation resource at the consumer or on the consumer side of PCC622. In one embodiment, energy source660is a renewable energy source, such as wind or solar power systems. In one embodiment, energy source660generates real power. In one embodiment, system600includes battery backup670. Battery backup can be any form of energy store or energy storage described herein. In one embodiment, the consumer includes local power converter650. Converter650can be in accordance with any embodiment of a converter described herein. Converter650performs one or more operations to manage or control an interface with the grid. In one embodiment, the interface represents the interconnection of a device to PCC622. In one embodiment, the interface represents the electrical interconnection or electrical coupling of a device to another point. For example, converter650can operate to adjust an interface between PCC622and loads640, such as by changing how power or energy is transferred between the grid and the load. In one embodiment, converter650can operate to adjust an interface between energy source660and load640, for example, to deliver power to the load from a local energy source. In one embodiment, converter650can operate to adjust an interface between energy source660and PCC622, for example, to deliver power from the energy source to the grid. In one embodiment, converter650can operate to adjust an interface between battery backup670and PCC622and/or energy source660, for example, to charge the energy store and/or provide power from the energy store to use for the load or the grid or both. Converter650enables system600to generate any combination of real and reactive power from energy source660. Thus, converter650enables the customer to perform reactive power injection into PCC622to adjust how the customer is seen from the grid side (i.e., from the perspective of meter620. In one embodiment, converter650adjusts operation in response to one or more commands from data center680to adjust a combination of real and reactive power provided by the DER at PCC622. FIG.7is a block diagram of an embodiment of a gateway aggregator system. System700is one embodiment of a gateway device, and can be or be included in a control node or DER node in accordance with any embodiment described herein. Aggregator710represents hardware and software logic to perform aggregation of data. Aggregator710can compute a determination of how to control an interface based on the aggregated information. In one embodiment, system700can be considered part of iGOS. Based on local and network information, aggregator710can determine how to manage energy within a DER node. Aggregation logic720represents logic that enables aggregator710to gather multiple elements of data related to electrical grid conditions. External I/O722represents sources external to a PCC, or on the “other side” of a meter, which can provide grid condition information. Typically such information is provided in light of conditions of the grid as a whole or of specific segments or sections of the grid that are larger than the consumer or neighborhood or portion managed by a control node associated with aggregator710. Examples of external I/O722can include, but are not limited to, dispatch information and grid control signals. Dispatch information can be broadcast to a grid network or can be sent to specific areas in a grid network. Grid control represents specific signals indicating at least one electrical condition the PCC is supposed to comply with and/or address. For example, the PCC can be requested to provide specific output from the PCC. As another example, the PCC can be specifically requested to comply with a regulation based on conditions at another location of the grid network. Sensors724represent sources of data within the PCC, for example, one or more sensors local to a control node or other gateway device or aggregation device. Examples of sensor data can include, but are not limited to, load information, local temperature, light conditions, and/or other information. In one embodiment, load information is gathered or monitored by a meter that determines what loads are drawing power, such as by energy signatures that indicate complex current vectors for the load. In one embodiment, load information can be configured into aggregator710, which can be maximum load capacities allowed for specific load connections (e.g., breakers, outlets, or other connection). In one embodiment, the operation of a local energy source can be affected by temperature, or the temperature can be an indication of expected efficiency or demand for certain loads and/or energy sources. Light condition is specific to solar systems, but other sensors such as wind sensors could alternatively or additionally be used. Each sensor can provide information to be considered when determining how to output power or otherwise control interfaces within the PCC or external to the PCC. In one embodiment, each sensor registers with aggregation logic720. Aggregation logic720can include a sensor control hub to gather and aggregate information from the various sensors. In one embodiment, aggregator710stores aggregation data or raw data in memory742. Memory742can be local to aggregator710and store sensor or grid control information. In one embodiment, aggregation logic720includes weights to provide greater weight to certain data over other data. The weights can change based on time or based on other data received. For example, temperature data can be considered in determining what operations to perform, but can be weighted very low or ignored completely when grid control is received. Countless other examples are possible. In one embodiment, aggregation logic720operates as a type of complex state machine. In one embodiment, each condition output generated by aggregation logic720identifies a state as determined based on the various inputs. For example, aggregation logic720can make determinations based on ranges of data, such as when light conditions are within a given range and the temperature is within a specific range, and when the grid conditions are within certain ranges, then a particular condition output is generated. Other ranges will produce other condition outputs. The condition outputs can indicate what the state of aggregator710is to determine how to control a power converter to operate. In one embodiment, aggregation logic720generates one or more conditions for execution by execution logic750. In one embodiment, aggregator710can include zero or more other logic elements to make changes to the determined conditions. In one embodiment, aggregator710includes either forecast logic730or forward prediction740or both. In one embodiment, all logic blocks within aggregator710can be considered control logic for the aggregator. Thus, reference to the aggregator performing computations or calculations can include operations of aggregation logic720, forecast logic730, forward prediction logic740, execution logic750, or other logic not shown, or a combination. In one embodiment, forecast logic730can receive rate source information732. Rate source information732can include consumer rate or price information or market rate or market price information. In one embodiment, consumer rates will include different rates for real and reactive power. In one embodiment, market rates will include different rates for real and reactive power. Reactive power can generally be delivered to the grid for an “ancillary market” or to provide ancillary services. Thus, reactive power rates can actually include many different rates depending on market conditions and the ancillary market selected. It will be understood that rate information can change throughout the day, or through the season or year. Thus, time of day and time of year can be information considered in computing operations to perform based on rate information. In one embodiment, rate source732is a realtime rate information source, and can provide data related to a deregulated energy market, such as rate contract information, instantaneous rates, or other information, or a combination. In one embodiment, aggregator710couples to rate source732via external I/O722. In one embodiment, forecast logic730makes a determination or calculates an operation to perform based on the condition(s) identified by aggregation logic720and rate information. Forecast logic730can determine one or more actions to take based on combining rate information with condition information. For example, a determined condition as calculated by aggregation logic720can identify a specific state or zone of operation for an interface managed by aggregator710. Aggregator710is associated with a control node that can provide power to local loads and to the grid. Thus, forecast logic730can determine the best use of locally generated energy, for example. Forecast logic730can determine how to best control interfaces based on where the maximum financial reward is for the consumer. For example, in a given day market price might fluctuate between real power and ancillary services, depending on the conditions of the grid network. When real power rates are higher, forecast logic730can determine to cause an associated power converter to generate real power to transmit to the grid. If one or more ancillary market prices then goes higher than real power market rates, forecast logic730can determine to cause the power converter to generate reactive power to transmit to the grid. In another example, consider that the consumer has loads that have load demand. However, because market rates are currently higher than the value of consuming the energy locally, forecast logic730determines to transmit the energy to the grid, and draw power from the grid to power the loads. Similarly, when market rates drop, forecast logic730can determine to redirect more energy to the local load demand. Thus, aggregator710can dynamically monitor and control the interface to the grid from the local PCC to maximize the value of energy for the local consumer and for the grid. In one embodiment, forward prediction740accesses historical information from memory742. The historical information can include one or more conditions with associated operations performed, historical trend information for rates, electrical conditions, power demand, and/or other information. The history or historical information can enable aggregator710to identify trends or patterns based on previous operation. Thus, the longer a control node is operational, the more its historical data can inform operation. In one embodiment, aggregator710includes a period of data gathering prior to using history information. The time of data gathering can be variable for the different uses of an aggregator, but can be a matter of hours, days, weeks, or even months. In one embodiment, such information can be gradually “phased in” by gradually giving more weight to historical data analysis or evaluation or calculation of what operations to perform. In one embodiment, historical data can identify particular states of operation and subsequent states of operation and how long elapsed between them. Thus, for example, forward prediction can determine whether or not to perform a determined action based on historical information indicating whether such a condition or state is likely to persist for long enough for economic benefit. In one embodiment, forward prediction740determines from selected actions or state and historical data what operations should be executed by a control node. In one embodiment, each prediction represents an estimate of what decision to make based on present conditions in light of past data of energy loads, energy prices, weather conditions, rates, or other information. In one embodiment, the historical data can be referred to as operating history or operational data, referring to operations within the monitored/controlled grid node. In one embodiment, execution logic750receives one or more conditions, one or more actions, or one or more predictions, respectively, from aggregation logic720, forecast logic730, and forward prediction logic740. Execution logic750can analyze the input data and compute or calculate one or more operations to perform based on the received data. In one embodiment, collectively, aggregator710can have knowledge of connected local energy sources, entrance meter information, energy store or energy backup system, local or onsite loads, and other information. In one embodiment, all the information gathered within a gateway device such as aggregator710is gathered by a local meter. Logic within aggregator710can receive the data from the multiple sources and make decisions based on the data. The aggregation of data itself is different from previous control nodes. Forecasting or prediction can be added to the aggregator. In one embodiment, execution logic750selectively generates an operation based on computed conditions, actions, and predictions. Consider an example that a meter detects that a refrigeration load has turned on and more reactive power is needed. The meter could make such a determination, for example, by computing or processing different load energy signatures of the loads. For example, consider a composite current that is already present in the system. The addition of another load coming online will change the overall composite current. In one embodiment, the meter can compute a difference between the new composite current and the previous composite current to determine the energy signature of the new load(s). As such, the meter can identify the specific load and determine to effect a change in operation via aggregator710to respond to the power demands of the specific load. It will be understood that such computations could require vector analysis and/or calculations to distinguish specific loads. In one embodiment, aggregator710can keep historical data for one or more energy signatures, and can thus determine how long a given load is expected to be on, based on historical averages. Thus, energy signatures can be used with historical data or other determination data computed in aggregator to determine what operation(s) to execute. Continuing with the example of the refrigeration load coming online, in one embodiment, the meter detects the increased demand for reactive power in the system. In one embodiment, the meter detects the energy signature of the refrigeration load. The gateway can have an attached solar system (local energy source) adjust its phase angle (e.g., via a converter and/or inverter coupled to the solar system) to produce more reactive power to address the refrigeration load. Once the refrigeration load turns off, the gateway can then tell the solar system to use the extra power to charge a battery backup system, or provide support to the grid. Again, the different possible examples are too numerous to address. In one embodiment, execution logic750generates an operation and executes the operation. In one embodiment, execution logic750can generate an operation for local output752or for market output754. Example local outputs can include, but are not limited to, providing real or reactive power or both to a load, providing real or reactive power or both to charge an energy storage device, or providing power to local “capacity,” which can represent one or more load and one or more energy storage devices. Examples of market outputs can include, but are not limited to, providing real power to the grid, or providing ancillary services. The ancillary services can include many different services, which are represented generically, even though not all possible services are illustrated. Ancillary services can include grid support, frequency support, regulation up, regulation down, or blackstart services, or other services, or a combination. Grid support represents any type of voltage support services to boost or reduce the grid voltage condition at the PCC. Regulation up and regulation down refer to specific frequency support services. Regulation up and regulation down can refer to controlling load interfaces to change a load seen at the PCC. Frequency support represents other types of frequency service, and can include changing an interface to change a flow of energy onto the grid to adjust a frequency of the AC power as seen at the PCC. Blackstart service represents operations performed to ramp a grid up to enable a disconnected portion of the grid to reconnect to the grid network. All ancillary services can include providing capacity that responds to a need by the grid as seen from the PCC. In one embodiment, aggregator710provides non-export services, referring to refraining from placing real power (watts) onto the grid. In general, in one embodiment, a DER node can be or include a control node. Typically a control node includes an energy meter and a controller. The controller can be in accordance with aggregator710or other gateway device. The energy meter and the controller are located on the consumer side of the PCC, and perform operations within the PCC to change an interface as seen from the grid via the PCC. The consumer node includes one or more power converters that change their operation in response to commands or controls from the controller or meter. The power converter operation changes the interfaces to the PCC in accordance with decisions made by the controller. Operation by the power converter(s) can change the flow of energy within a grid network at the local node. Thus, the power converter can respond to aggregation information by changing operation in response to a decision by a controller that determines how to operate based on the aggregation information. The aggregation information can include information from one or more sensors, one or more grid-side controllers or data center, and local power demand and local conditions. The decision-making by the controller can include computing based on the gathered local and grid condition information. In one embodiment, the decision-making includes computing based on rate information. In one embodiment, the decision-making includes computing based on historical information. In one embodiment, the decision-making includes computing by execution logic to generate one or more controls for one or more power converters. The power converters change the flow of energy within the PCC or between the PCC and the grid, in accordance with any embodiment described herein. The power converters can control a mix of real and reactive power from a local energy source or from the grid, in accordance with any embodiment described herein. FIG.8is a block diagram of an embodiment of a DER node. System800includes customer premises810. Customer premises810represents a grid consumer, and includes energy generation resources840. Generation resources840can include any type of generator or renewable resource such as solar system842. In one embodiment, generation resources840include storage844, which can store energy for later retrieval. Customer premises810includes load812, which can represent one or more individual loads for the premises, or can represent the entire customer premises. Load812can have a particular harmonic signature. In one embodiment, customer premises810includes iGOS830, which represents an intelligent platform for energy management of energy generated and consumed at customer premises810. iGOS830can be in accordance with any embodiment described herein. In one embodiment, customer premises810interfaces with grid802via meter820. In one embodiment, meter820is a four quadrant meter. As a four quadrant meter, meter820can indicate not only the quantity of real and reactive power, but in what quadrant the operation currently is. More details regarding the four quadrant meter operation are provided below with respect toFIG.11. In one embodiment, solar842provides its power for available use by load812or to export to grid802via converter852. Converter852represents a microinverter that can provide on-demand reactive power from a real power source. Thus, while solar842outputs DC power, converter852can provide AC output with any phase between the output voltage and current, by driving the current based on a reference waveform, and allowing the voltage to follow the current. Converter852has electrical isolation between the input and output, and the electrical isolation allows the device to impedance match both input and output by simply transferring energy between the input and output, instead of regulating a specific voltage or current. Converter854can be the same as converter852, and provides a power interface to storage844. In one embodiment, storage844will include a separate converter to provide DC power to charge the battery. Customer premises810illustrates three components of an intelligent platform for energy management. The first is iGOS830to monitor, analyze, and regulate fluctuations of energy use. The next is a converter to manage and modulate voltages and frequencies, and communicate the information multilaterally to consumers, grid operators, and utilities. The converters are capable of reactive power generation, as has previously been stated. The third includes meter820and iGOS830to perform data collection to aggregate all information from multiple sources in order to increase overall system intelligence and reliability. In one embodiment, the overall aggregated information occurs only at the control center. When operating together, system800can provide the smartest energy decisions for the end-user at any given time, whether it is to increase renewable energy generation, reduce energy consumption, delay use of grid-delivered energy, sell excess energy to the grid, or other decision, or any combination of decisions. FIG.9is a block diagram of an embodiment of a DER node for a distributed power grid. Node900represents a DER node, and can be an example of a DER node or control node in accordance with any embodiment described herein. Node900includes various hardware elements to enable its operation. In general, the hardware can be described as processor910, power distribution hardware920, and power monitoring hardware930. Each of these elements can include specific types and functionality of hardware, some of which can be represented by other elements ofFIG.9. Processor910represents one or more controllers or processors within node900. In one embodiment, node900includes a power meter, a power converter, and control hardware to interface the two elements and couple to the grid. In one embodiment, each separate item includes a controller, such as a controller within the metering device, and a controller within the power converter. The power converter can include a power extractor controller, an inverter controller, and another controller to manage them. Thus, controller910can represent multiple controllers or elements of control logic that enables node900to monitor and distribute power. Processor910manages and controls the operation of hardware within node900, including any hardware mentioned above. Processor910can execute to provide iGOS for node900. In one embodiment, processor910executes logic to provide at least some of the functions described with respect to node910. To the extent that functions described are provided by hardware, processor910can be considered a controller to control the operation of the hardware. In one embodiment, processor910executes a DER node operating system for node900. In one embodiment, the operating system is iGOS. The iGOS platform can provide computing, and general control over the operation of node900. In one embodiment, iGOS enables the node to collect data and make decisions to send data outside the node. In one embodiment, iGOS can use the data to control the local system, such as the local elements coupled to a same side of a PCC. In one embodiment, iGOS also sends data for use by external entities, such as a utility manager or other nodes in the grid network. In one embodiment, iGOS controls dispatch functionality for node900. The dispatching can include providing and receiving data and especially alerts used to determine how to distribute power. In one embodiment, the iGOS can enable autonomous dispatching, which allows the nodes of the grid network to share information among themselves that control the operation of the grid. The autonomous dispatching refers to the fact that a central grid operator does not need to be involved in generating or distributing the dispatch information. In one embodiment, iGOS enables control functionality. The control can be by human, cloud, or automated control logic. In one embodiment, the iGOS enables node900to work independently as an individual node or work in aggregate with other DER nodes in a grid network. The independent operation of each can enable the distributed network to function without a central power plant, or with minimal central grid management. In one embodiment, the iGOS can enable blackstart operation. Blackstart operation is where node900can bring its segment of the grid back up online from an offline state. Such operation can occur autonomously from central grid management, such as by each node900of a grid network independently monitoring conditions upstream and downstream in the grid network. Thus, node900can come online when conditions permit, without having to wait for a grid operator to control distribution of power down to the node. Node900can thus intelligently bring its node segment back up online by controlling flow of power to and from the grid, and can thus, prevent startup issues. In one embodiment, iGOS enables virtual non-export operation. Non-export includes not outputting power onto the grid. However, with the iGOS, node900can convert real power to reactive power, and continue to export power, but not of a type requested by the grid, instead of simply dumping watts onto the grid. In one embodiment, the iGOS enables node900to offer multiple line voltages. In one embodiment, grid interface980, which may be through control logic of processor910, can be configured for multiple different trip point voltages. Each trip point voltage can provide a different control event. Each control event can cause processor910to perform control operations to adjust an interface of the DER node. The interface can be an interface to a load and/or an interface to the grid network. In one embodiment, the iGOS can economize interconnects within the grid network. In one embodiment, node900controls backflow (e.g., through non-export) onto the grid network by limiting the backflow, or adjusting output to change a type of power presented to the grid. In one embodiment, node900provides utility control functions that are traditionally performed by utility grid management that controls flow of power from a central power plant. Node900can provide the grid control functions to enable a distributed power grid. Power distribution hardware920includes power lines, connectors, phase locked loops, error correction loops, interface protection or isolation such as transformers, or other hardware or a combination that enables the DER node to transfer energy from one point to another, to control interfaces to control how power flows throughout the grid, or other operations. In one embodiment, a power converter can be included within the power distribution hardware. A power converter can be a smart inverter or microinverter. Power monitoring hardware930includes connectors, signal lines, sampling hardware, feedback loops, computation hardware, or other hardware that enables the DER node to monitor one or more grid conditions or load conditions or both. The grid conditions can be or include voltage levels, phases, frequencies, and other parameters of the grid operation. The load conditions can be or include voltage, current, phase, frequency, and other parameters of power demand from loads. In one embodiment, node900includes grid control940. Grid control represents hardware and logic (e.g., such as software/firmware logic, configurations) to control an interface to the grid network. In one embodiment, grid interface980represents grid network interfaces. Grid control940can include real power control942and reactive power control944. The real and reactive control can be in accordance with any embodiment described herein. In one embodiment, real power control942includes logic (hardware or software or a combination of hardware and software) to provide real power to the grid. In one embodiment, reactive power control944includes logic to provide reactive power to the grid. Providing power to the grid can include changing an interface to cause power of the type and mix desired to flow to the grid. In one embodiment, node900includes local control950. Local control represents hardware and logic (e.g., such as software/firmware logic, configurations) to control an interface to the load or to items downstream from a PCC coupled to a grid network. Local control950can include real power control952and reactive power control954. The real and reactive control can be in accordance with any embodiment described herein. In one embodiment, real power control952includes logic (hardware or software or a combination of hardware and software) to provide real power to a load. In one embodiment, reactive power control954includes logic to provide reactive power to a load. Providing power to the load can include changing an interface to cause power of the type and mix desired to flow to the load from a local energy source and/or from the grid. It will be understood that a utility power grid has rate structures that are based on not just the amount of use, but the time of use. For example, a utility grid can have tiered rates. In one embodiment, processor910includes rate structure information that enables it to factor in rate structure information when making calculations about how to change an interface with grid control940or with local control950. Factoring in rate structure information can include determining what type of power (real or reactive) has more value in a given circumstance. Thus, processor910can maximize value of energy production or minimize the cost of energy consumption. In an implementation where tiered rate structures exist, processor910can instruct grid control940or local control950based on how to keep consumption to the lowest tier possible, and how to provide power at a highest rate possible. In one embodiment, processor910takes into account utility or grid network requirements when controlling the operation of grid control940or local control950. For example, the grid may have curtailments or other conditions that affect how power should be provided or consumed. In one embodiment, node900can adjust power output as loads dynamically come online and offline. For example, local control950can reduce output when loads go offline, and can increase output when load come online. Metering960represents metering capability of node900, and can include a meter in accordance with any embodiment described herein. In one embodiment, metering960can include load control metering962. Load control962can include logic to monitor load power demand. In one embodiment, metering960can include signature manager964. Signature manager964includes logic to create, store, and use energy signatures in monitoring what is happening with loads. More specifically, signature manager964can manage energy signatures including complex current vectors in accordance with any embodiment described herein. Traditionally, a net energy meter was required to connect to the grid. However, newer regulations may prevent connecting to the grid at all unless certain capabilities are met. Metering960can enable node900to control an inverter or converter to respond to specific loads or to specific energy signatures identified on the line. Based on what metering960detects, node900can provide realtime control over energy production and load consumption. In one embodiment, node900includes data interface970. In one embodiment, data interface970includes data manager972to control data that will be sent to a data center or data management, and data that is received from the data center or data management. Data manager972can gather data by making a request to a data center or comparable source of data. In one embodiment, data interface970includes external manager974, which can manage the interface with a data center, central grid management, other nodes in the grid network, or other data sources. In one embodiment, data manager972receives data in response to data sent from a data source. In one embodiment, external manager974makes a request for data from a data source. The request can be in accordance with any of a number of standard communication protocols or proprietary protocols. The medium for communication can be any medium that communicatively couple node900and the data source. In one embodiment, external manager974communicates with a data source at regular intervals. In one embodiment, external manager974communicates with the data source in response to an event, such as more data becoming available, whether receiving indication of external data becoming available, or whether data manager972indicates that local data is ready to send. Data interface970can enable realtime data for market use. In one embodiment, data interface970provides data collection, which can be used in one embodiment to identify currents for energy signatures. In one embodiment, node900includes grid interface980. In one embodiment, grid interface980includes utility interface982to interface with a utility grid. In one embodiment, grid interface980includes virtual interface984to interface with a distributed grid network. The operation of the grid interface can be referred to as MGI (modern grid intelligence), referring to execution of an MGIOS by processor910. Grid interface980can include any type of interface that couples node900to grid infrastructure, whether traditional utility grid infrastructure or distributed grid networks. In one embodiment, grid interface980can enable node900to know a power direction. In one embodiment, the grid network provides dispatch information, such as provide a signal from a feeder to indicate a power direction. Node900can manage its operation based on the direction of power flow in the grid network. Grid interface980can also dynamically monitor changes in direction of power flow. In one embodiment, the iGOS enables node900to adjust operation of one or more elements connected downstream from a PCC, to scale back operation of the grid. Consider an example of air conditioners coupled downstream from a PCC. In one embodiment, the iGOS can detect that the grid network is experiencing heavy load, and can determine to slow down all air conditioners to relieve the grid for 5 to 10 minutes. Thus, the devices do not need to be stopped, and the grid does not need to shut off power to any segment. Instead, the power can be reduced for a period of time to selected loads to allow the grid can recover itself. Thus, the iGOS can control the load or the sources. Such operation can reduce or prevent brownouts or rolling blackouts, for example, by scaling power demand back instead of completely shutting supply down. It will be understood that node900requires a certain amount of power to operate. The power consumed by node900can be referred to as tare loss, which indicates how much power the controlling devices consume when the node is not generating power. In one embodiment, node900includes a sleep feature to reduce tare loss. For example, a node that controls a metastable energy source such as solar can sleep when there is no sun, and can wake up when the sun comes up. In one embodiment, the node can default to a low power state and awake in response to a signal from a solar detector, power over Ethernet, or some other external signal trigger to wake it up. In one embodiment, a node can wake up during a sleep cycle at night to perform upgrades or perform other ancillary services. FIG.10is a block diagram of an embodiment of an intelligent grid operating system. System1000represents a grid network system in accordance with any embodiment described herein. In one embodiment, iGOS1010is implemented in DER1004. In one embodiment, iGOS1010is implemented in a control center that communicates with intelligence in DER1004. System1000includes grid1002, which represents a utility grid that allows DER aggregation. iGOS1010executes software platform1020, which can include features and services such as market analytics, behavior monitoring and learning, and prediction. In one embodiment, iGOS1010includes cloud computing resources. In one embodiment, the system stores and analyzes historical data, and can report alarms. The system provides a user interface for operation, such as a command user interface that enables the execution of various command functions for associated DERs1004. In one embodiment, iGOS1010includes software that complies with industry standards, such as UL safety standards, DER aggregation standards, or communication protocols. The iGOS platform does more than create power. It also provides necessary management functions built right in. In one embodiment, iGOS1010can be envisioned as having cloud connection and aggregation, software layer(s) of platform1020, and hardware association or control through hardware platform1030. The software and hardware can provide the delivery of services, as well as built-in functionality. In one embodiment, iGOS includes realtime, on demand data and control for: 1. energy management; 2. real-time dispatch and control; 3. revenue grade metering and billing; 4. prediction, modeling, forecasting, and historical data; and, 5. secure node networking with DNP3 and IEEC 61850. In one embodiment, hardware platform1030includes aggregator1032to aggregate information from multiple sources, and potentially from multiple DERs. In one embodiment, hardware platform1030can be considered to include load1034, which represents loads within a managed consumer premises. It will be understood that a load is a dynamic concept, as a user will continually turn loads on and off throughout the day. Hardware platform1030includes inverter1036, which represents a microinverter or power converter in accordance with any embodiment described herein. iGOS1010can control the functions of the hardware elements of hardware platform1030. In one embodiment, hardware platform1030can also integrate the function of third party hardware resources1038, such as storage, meters, air conditioning units, motors, electric vehicles, or other hardware. In one embodiment, iGOS1010factors utilization1070of the grid and of the local hardware resources. In one embodiment, iGOS1010factors production1060of energy by DER1004to determine what actions to take, and what services can be provided to grid1002. iGOS1010can provide any one or a combination of services1040, such as energy, capacity, ancillary services, volt/VAR support, frequency support, regulation up and down, or blackstart. In addition to services, iGOS1010includes built-in functionality1050, such as dynamic total harmonic distortion (THD) control to remove harmonics by adjusting operation relative to an idealized reference waveform, dispatch and control, demand/response, energy output and control, real power output and control, reactive power output and control, apparent power output and control, or non-export. In one embodiment, iGOS1010can service loads at the highest load factor, while dynamically exchanging information with energy resources, such as the utility, ISO dispatched generators, renewable resources, and on site storage. In one embodiment, the software can include the operating system implementation at the node, where multiple nodes are connected via the cloud. Further built-in functionality can include dispatchable control over all aspects of energy production and consumption. FIG.11is a block diagram of an embodiment of a four quadrant meter with an intelligent grid operating system. System1100represents a four quadrant meter system. System1100includes meter1110, which can communicate with iGOS1120. Meter1110reads data out to monitor system1100, which readings it can provide to iGOS1120. In one embodiment, iGOS1120can provide control commands or communication to meter1110. The elements of system1100include iGOS1120, inverter1130, generation1140, and storage1160can be in accordance with any embodiment described herein. Market data1150represents information obtained from an external source to determine what market demand and market prices exist. In one embodiment, market data1150represents a realtime stream of information from one or more sources. As before, generation1140represents the ability to generate energy, and storage1160represents storage capacity. Inverter1130represents a power converter that enables the realtime generation of reactive power and apparent power, and enables reactive power injection into a coupling node monitored by meter1110. Regarding meter1110, real power is represented on the x-axis, and reactive power is represented by they-axis, with positive and negative power directions indicated. Positive power is energy from the grid, and negative energy is power generated locally at the consumer premises or DER. Depending on the quadrant (1, 2, 3, or 4), iGOS1120can control operation of the system at the DER. In one embodiment, iGOS1120dynamically changes the local output (by adjusting real power generation1140, reactive power generation through inverter1130, or both) to adjust the current quadrant of operation. The quadrant is where the apparent power is. Basically, the meter puts apparent power on a unit circle. In one embodiment, iGOS1120executes based on market data1150, and which quadrant the apparent power is in. Generation1140, inverter control1130, and storage1160can all be controlled based on the market and quadrant location. The differences in market price and peak demand can affect the operation to move apparent power into the most valuable quadrant. In one embodiment, the system can couple harmonic control with the four quadrant information. In one embodiment, the DER of system1100may be operating in one quadrant, and based on market data1150, iGOS1120determines that it would be more valuable to more to a different quadrant. iGOS1120can provide control signals to adjust the operation of inverter1130to change power generation output to move the apparent power into a different quadrant. For example, moving from quadrant 4 to quadrant 1 can involve ceasing to generate reactive power. Then real and reactive power would come from the grid. Alternatively, moving from quadrant 2 to quadrant 3 would involve continuing to export real power, but also generating more reactive power to move quadrants. Meter1110can identify a quadrant of operation based on a direction of the flow of energy, and can thus determine quadrants based on inflow or outflow of both real power and reactive power. System1100can adjust the quadrant of operation based on market data, based on local demand (e.g., based on loads, not specifically shown), based on a dispatch or control signal from a control center or from grid control, or for a combination of these. FIG.12Ais a block diagram of an embodiment of an intelligent grid operating system managing grid interconnect of a DER node. System1200represents elements of an iGOS system. System1200includes local information1210, which can be information from local loads, local metering, and local energy generation. Based on this information in realtime, system1200can determine what capabilities the DER system has, and where it can operate with respect to a meter quadrant. iGOS1240represents the iGOS system in accordance with any embodiment described herein. iGOS1240controls output hardware1230to control the operation of the DER. Internal operations1242represent the internal operations determined by iGOS1240based on local information1210. For example, based on availability of local energy generation, and a demand from local loads, iGOS1240may determine how to operate to satisfy the local demands. When local generation is more than local demand, iGOS1240can identify the excess through the metering. Internal operations1242can also include metering to determine efficiency of internal operations. In one embodiment, iGOS1240also factors in grid interface1244. Internal operations1242represent the energy state and management for local load and generation. Grid interface1244, in contrast, represents how the interface with the grid is perceived by the grid. Internal operation1242can be thought of as “inside the meter,” and grid interface1244represents what is presented to the grid “at the meter,” or looking in from the other side of the meter. There are many scenarios where what might make the most sense for internal operations1242is different from what is the best operation when factoring and balancing grid interface1244. The balance can include information from IPPs, ISOs, IOUs, or other grid information1220. Grid information1220represents what is happening at the grid from an operational standpoint (e.g., what is the power factor at the point of connection), as well as from a market standpoint (for example, what market demands currently exist for services). Based on the grid and the energy markets, iGOS1240can cause output hardware1230to adjust operation to present a different interface to the grid. In one embodiment, the results of the internal operations as provided through output hardware1230responsive to control from iGOS1240is the basis of what grid interface will be. Based on grid information1220, iGOS1240can adjust the internal operations, which appears to then generate different results responsive to grid interface feedback. Grid interface1244provide power in and power out to grid1202. Grid1202includes IPPs, IOUs, ISOs, RTOs, end users, and municipalities. iGOS1240can balance the needs of the grid with the capabilities and services available locally from the DER. Thus, it will be understood that there is an overlap of energy metering, load demand, and on-site energy generation. These components can be related in a triangle, as there is a relationship between load needs and on-site generation and energy metering. Such consumer-end demand, energy generation, and metering can be balanced within a grid ecosystem of grid1202, which is informed by the other triangle with IPP, RTO, and IOU. While the triangles are illustrated as balancing against each other, it will be understood that the grid ecosystem of system1200includes components other than just IPP, RTO, and IOU, and load, on-site generation, and metering. Other components can include the end-user, such as the behavior of the user in addition to the consumer-end equipment illustrated on the other side. Also, municipalities and other regulatory organizations. In addition to these, the independent service operators (ISO) also factor into the environment. As described herein, the iGOS system can manage the balance for the consumer-end hardware in the grid ecosystem. FIG.12Bis an embodiment of table data to illustrate grid interconnect management for a DER node. Table1250provides an example of a flow based on realtime monitoring and control. Consider that the categories of results1252, realtime data1254, realtime (RT) power1256, realtime voltage1258, and realtime current1260represent various quantities measured and controlled on a constant basis within a DER by an iGOS system. Assume for the example that the system, either by design as a result of a control command, or because of some condition on the grid or the sudden appearance of or disappearance of certain loads, realtime data1254indicates that there is reactive energy in Q1 (quadrant 1). In one embodiment, the change in reactive power in Q1 at (1) will correspond with a change in reactive power in Phase B (assuming a three-phase system). The Phase B change appears in the realtime power measurements of1256at (2). The change in reactive power in Phase B may cause a change in voltage between Phase A and Phase C, as indicated in realtime voltage measurements1258at (3). The change in voltage can in turn cause a change in the current of Phase A and the current of Phase C, as illustrated in realtime current measurements1260by the arrows. It will be understood that all these values can be constantly monitored, and thus, detected. In one embodiment, as the current and voltage changes occur, the apparent power in at least one phase will change, as illustrated by realtime power measurements1256at (4). In one embodiment, the change in apparent power can cause a real energy change that causes energy to be imported, as shown by the arrow to results1252. Based on the measurements, the system can respond and adjust its operation to compensate for the changes. The initial reaction to the changes may occur quite quickly (within a matter of seconds or less), even though it may take a matter of several seconds for the adjustments to have a complete effect. In one embodiment, in response to the import of energy based on the reactive energy change, the system identifies that one or more harmonics are being caused or introduced, as illustrated in realtime data1254at (5). In response to the harmonics, the iGOS system can provide volt/VAR support and dynamic THD control to adjust for the distortion. Based on the correction as illustrated at (6), the result can be to compensate and then export real energy as shown in results1252. Thus, the system can respond in a way opposite the change to adjust for its effects. FIG.13is a graphical representation of an embodiment of components of a current in a system in which harmonic components of current have angular offsets with respect to a primary current component. Diagram1310provides a complex vector representation of current. A vector has a magnitude and a direction. Instead of simply measuring power as traditionally done, in one embodiment, a meter or a DER node can monitor power as an energy signature including a representation of a complex power vector. In one embodiment, each signature identifies characteristics to define or “name” the signature. Each signature includes a complex vector representation that provides a vector for primary current and a vector for one or more harmonics. Vector1320is the vector for primary current. In typical representation, the x-coordinate is the vector component that extends from left to right across the page. The y-component goes from bottom to top of the page. It will be understood that while not represented here for purposes of simplicity, a vector could have a negative y-component. The x-y coordinates define the end of the vector. Now assume that the x and y coordinates of primary current vector1320define a plane. The most correct way to envision the harmonics, in accordance with research and work done by the inventors, is to represent the harmonics as a three-dimensional vector. Thus, if the x-y coordinates of vector1320define a reference plane, one or more of the harmonics can have an angular offset relative to the plane of the primary current vector. For example, consider the example of diagram1310. The first harmonic is illustrated as having vector1330, which includes an x component and a y component, where the magnitudes of the components can be any magnitude with respect to the primary current components. In addition to the x and y coordinates, first harmonic vector430includes a z coordinate component, which defines angular offset1352of the vector with respect to the reference plane of primary current vector1320. It will be understood that the starting points of the primary current and the harmonics are the same. Thus, the third dimension of the harmonic vectors or the complex vectors is not necessarily an absolute z coordinate component, but an angular offset relative to the primary current. As illustrated, third harmonic vector440also has an x component and a y component, and angular offset1354, which can be different (greater or less than) angular offset1352of first harmonic vector1330. The angular shift of the angular offsets represents a magnetic effect on the current. The inventors have measured noticeable effects on power consumption up to the fortieth harmonic. Thus, the contribution of harmonic offsets should not be understated. The harmonics shift with respect to the angular offset due to the differing resonant effects of magnetic flux when trying to move a current. Primary current vector1320is the current the consumer expects to see. However, the harmonic components can add significant (measurable) power consumption. The offsets of the harmonics can shift the simple expected two-dimensional current vector into a three-dimensional current vector (complex current vector). The traditional power triangle does not fully address the power usage by the consumer, as additional power will be required to overcome the magnetic components represented by the shifted or offset harmonic components. FIG.14is a graphical representation of an embodiment of components of a current in a system in which a current vector is a composite of a primary current component and harmonic current components. Diagrams1410,1420,1430, and1440illustrate component parts of a complex current vector in accordance with an embodiment of diagram1310ofFIG.13. As illustrated, diagram1410represents the primary current vector1412. The primary current includes x and y components, and defines a reference frame for the harmonics. Diagram1420represents first harmonic vector1422, which includes x and y components and angular offset1424. Diagram1430represents third harmonic vector1432, which includes x and y components and angular offset1434. Diagram1440represents fifth harmonic vector1442, which includes x and y components and angular offset1444. Each of the primary current1412and various harmonics (1422,1432,1442) are shown as two-dimensional “power triangle” representations, which is what is traditionally expected for each one. However, as mentioned already, the harmonics are frequently at an angular offset with respect to the primary current component vector, and thus the resulting composite current vector will not be in the same plane as primary current vector1412. Rather, consider the power triangle of the composite current vector as a triangle in a three dimensional box. Diagram1450provides a simple illustration of this concept. It will be observed that primary current vector1412is on a face of the three dimensional box of diagram1450. The harmonics push the triangle for the composite current “into” the box in some way. Composite current vector1452is both larger in magnitude, and offset angularly with respect to primary current vector1412. Offset1454represents the angular offset. It will be understood that primary current vector1412and composite current vector1452define the “shape” of the box. Depending on the amount of harmonic contribution, the box shape will be different. The composite current vector1452can be a signature stored by the metering device. The reference plane of primary current1412can be defined as a plane of the grid power (referring to the power condition as seen at the grid via the PCC. With respect to the noise and harmonics generated, it will be understood that there are regulations on switching power supplies and magnetic resonance in general. Each device is tested for compliance (e.g., UL certification). When each device or load works individually as designed and tested, each one will comply as required per regulations. However, when there are multiple loads or devices coupled together, they tend to create unanticipated resonance. The inventors have measured contributions to the energy triangle from the first up to the 51st harmonic. Thus, there is typically a significant amount of harmonic noise happening on the power lines. Harmonic suppression traditionally includes filters that target specific noise components. However, the noise components can continue to vary as different devices come online and offline, and the electrical resonance structure of the network continually changes. In one embodiment, a meter detects the characteristics of each load or group of loads. The characteristics can be referred to as a signature of the harmonics. In one embodiment, the power meter or energy meter can detect such shifts as the angular offsets of the harmonic current vectors, by measuring energy contributions. The power converter can compensate for the actual composite current by providing the reactive power needed to match the load or PCC to the grid. Thus, the current at the load can be adjusted by the converter to bring the composite current into alignment with the grid, not simply in power factor, but in complex vector. Such operation will naturally eliminate or at least reduce harmonic distortion caused by loading on the grid. In one embodiment, what is described in reference to loading can also be performed with reference to energy generation. In one embodiment, the meter can determine an energy signature at the PCC and compute what current would be needed to offset the grid to a desired offset (if some power factor other than unity is desired) or to match to the grid in a case where unity power factor is desired. The converter can adjust operation to adjust the power output to not only match reactive power needs, but complex current vector shift as well to more efficiently match the interface of the grid with the downstream from the PCC. It will be understood that the energy triangle represented in diagram550can be represented as a mathematical representation of the effect seen when looking at the current component of power drawn by a load or consumer. The effect is wasted energy, which usually manifests itself as heat. The problem traditionally is that systems do not match well, and there are significant noise components. In one embodiment, a DER node matches not just impedance, but matches noise or harmonic correction to provide a specific energy signature connection to the grid. Thus, the DER node can provide a “cleaner” connection to the grid network with respect to the power interface, whether outputting power onto the grid or receiving power from the grid. FIG.15is a block diagram of an embodiment of load factor control. It will be understood that traditional pricing for a consumer is based on peak demand, as illustrated by the 100% mark in diagrams1510and1530. The user pays rates for the availability of the peak demand, even if the peak demand was used for only a small portion of the day. It will be understood that diagrams1510and1530are very simplistic for purposes of illustration, and a real peak demand curve would have a significant number of peaks and valleys. The end result is that the customer pays for the “whole box” from the 100% mark to the entire day's demand. However, it is typical for peak demand to occur for a short period of the day, and to have lower demand for other portions of the day. The “white” space is demand paid for by rate, but not used. Thus, for diagram1510, there is a significant amount of underutilization1516, which is the white space, because peak demand1514places max1512fairly high relative to the average usage. Load factor control by iGOS can eliminate the peak demand by adjusting the operation of the local system. Thus, in diagram1530, peak demand1514is shown as being reduced utility demand1522. The reduced peak demand means that max1532is much lower relative to the average usage, and peak demand1534is significantly different. Underutilization1536is correspondingly much smaller as well. The iGOS includes the use of hardware that can provide any combination of real and reactive power. The iGOS system can also manage use and production to draw energy from the grid in intelligent ways to improve grid operations, as well as to maximize value usage by the node. In one embodiment, iGOS utilizes a four quadrant meter to manage and control load factor. Thus, by intelligent use of the DER energy resource, iGOS can significantly reduce the demands on the grid, offering significant savings to the customer. The utility also benefits, because they do not have to have as much capacity available to satisfy such a high peak demand, but can even out the operation of the grid, which provide stability. The worst-case scenario, which is usually among the dominant design criteria, is a reduced worst case, which increases efficiency of the grid. FIG.16is a block diagram of an embodiment of a system that transfers power from a local source to a grid-tied load with reactive power injection. System1600illustrates a grid-tied converter that couples to an energy source, a load, and a grid. Converter1620of system1600represents a converter for a DER node, which can be in accordance with any embodiment described herein. System1600represents a power system that includes metastable energy source1610, converter1620, load1602, and utility power grid1630. Load1602represents a consumer tied to grid1630. Grid1630can be any embodiment of a grid network described herein. Metastable source1610(e.g., solar cells/array, wind power generator, or other time-varying or green power source) and converter1620are local to load1602, as being on a same side of a PCC, and provide power to the load. In one embodiment, metastable source1610produces a variable/unstable source of DC power. The source may be time-varying and/or change in available power due to environmental conditions. Converter1620represents a dynamic power extractor and inverter apparatus. Source1610is a variable or unstable power source. System1600includes converter1620, which includes DC/DC converter1622, coupled to DC/AC inverter1624, both of which are coupled to and controlled by controller (CPU)1640. Additionally, switching device S1626(e.g., a relay) selectively connects the inverter to load1602and grid1630. Under normal operation, DC power is drawn from source1610, and extracted, inverted, and dynamically treated by converter1620, to dynamically produce maximum AC current relatively free of harmonic distortion and variability, and at a desired phase with respect an AC voltage signal from grid1630. Putting the generated AC current in phase with the grid AC voltage produces AC power with a power factor at or near unity to load1602, meaning that all reactive power drawn by the load comes from grid1630. If source1610produces enough energy to satisfy the real power requirements of load1602, converter can cause the only AC power drawn from grid1630by the load to be exclusively or nearly exclusively reactive power. When source1610is unable to produce DC power sufficient to completely satisfy the power demand from load1602, converter1620can adjust an interface to allow real power to flow from grid1630to load1602. In one embodiment, converter1620can generate AC current intentionally out of phase to a certain extent with respect to the AC voltage signal of the grid. Thus, the single converter1620can deliver power at any desired power factor to compensate for conditions of power on power grid1630. In one embodiment, multiple converters1620can operate in parallel at the same interface, and each can generate power with the same power factor, or each can be dynamically configured to produce different mixes of real and reactive power. When energy source1610generates sufficient power to satisfy load1602, the inverter current and the grid current will flow towards grid1630. In general, power can be given back generally to the grid, and the consumer can be appropriately compensated for power provided to the grid. In one embodiment, a give back scenario can involve providing power to a neighbor consumer, in accordance with any embodiment described herein. In one embodiment, power meter1632represents a meter to measure real power consumed by load1602. In one embodiment, VAR meter1634represents a meter to measure the reactive power consumed by load1602. In one embodiment, power meter1632and VAR meter1634can be combined physically and/or functionally by a meter. The meter can be on the side of grid1630. In one embodiment, the meter (combining meters1632and1634) is located with a PCC to connect to the grid, and is part of a DER node with converter1620. Such a meter can be in accordance with any embodiment described herein. In one embodiment, typically meter1632measures the voltage and current and computes power from those measurements. It will be understood that in the case only reactive power is drawn from grid1630, power meter1632will not measure any power usage by load1602. VAR meter1634can measure and compute the reactive power drawn, such as by measuring the phase of the current and voltage of the grid power at the load, and performing calculations based on the measured values. As discussed, in one embodiment, the power factor delivered by converter1620to load1602is at or near 1.0 relative to grid1630. Thus, converter1620can perform power factor correction. In one embodiment, converter1620can provide harmonic distortion correction. In one embodiment, converter1620provides table-based harmonic distortion correction. Previous harmonic distortion techniques use a hardware-based method or Fast Fourier Transform (FFT). The table-based method implemented on a processor or controller reduces cost per inverter and scales better than typical hardware implementations, and can be in accordance with what is described with reference to system800. Inverter1624of converter1620generates output in accordance with a desired power factor (unity or otherwise). In one embodiment, inverter1634monitors the operating conditions at the point of connection to load1602, and provides maximum power from source1610dynamically and in real time with changes in the energy source and current load. Thus, if the amount of energy generated by source1610changes, converter1620can modify the output based on that source in real time. Additionally, if the resistive conditions of load1602(e.g., an inductive motor such as a vacuum is turned on), converter can automatically generate changes to power output to track the needs of the load. All such changes can occur in realtime as conditions vary. In one embodiment, converter1620can provides output adjustments that provide total harmonic distortion control for harmonic distortion more efficiently than what is required by standards, thus complying with standards and improving performance of the system by dynamically adjusting to variable and unstable power sources, and to a changing load. It will be understood that if the output voltage and current of converter1620are matched in phase with each other and with the voltage on the grid (e.g., through a phase lock loop, or through a power generation sampling and feedback mechanism), any reactive power necessary will be absorbed from the grid. The more real power provided by source1610, the further out of phase the grid voltage and the grid current will be locally at load1602. If all real power is provided locally, the current and voltage of the grid will be 90 degrees out of phase locally at load1602, causing the grid real power contribution to fall to 0 (recall that Preal=(Vmax*Imax/2)cos(Vphase−Iphase)). In one embodiment, DC to DC converter1622of power converter1620includes input and output portions, as represented by the dashed line separating the device into two portions. The portion coupled to source1610can be referred to as an input portion, and the portion coupled to DC to AC inverter1624can be referred to as the output portion. In one embodiment, the operation of converter1622is to vary input impedance and output impedance to transfer energy from source1610to inverter1624. In one embodiment, converter1622can be referred to as a power extractor. Converter1622can impedance match to change an interface on the input to maximize energy transfer from source1610without fixing the voltage or current to specific values. Rather, the input can allow the power to float to whatever voltage is produced by source1610, and the current will match based on whatever total power is produced. Similarly, on the output, converter1622impedance matches to change an output interface to allow the load (in this case, inverter1624) to draw whatever power is needed at whatever voltage the inverter operates at. Thus, the output of converter1622can float to match the voltage of inverter1624, and generate current to match the total power. Converter1622can generate an output current waveform, where the magnitude is determined by how much energy is available, and whatever voltage inverter1624is at. Thus, the output floats to match the load, and is not fixed at current or voltage. An internal node within converter1622can act as an energy reservoir, where the input impedance matching enables the efficient charging of the internal node, and the output impedance matching enables the load to draw energy from the internal node. The input and output both couple to the internal node via inductors and/or transformers to isolate the input and output from each other and from the internal node. Controller1640can monitor the AC current, which moves out of DC/AC inverter1624, and the generated voltage of grid1630, which appears across load1602. Controller1640controls at least one electrical parameter of the interfaces of converter1622to control its operation. Parameters1642and/or1644represent control from controller1640to control the operation of converter1622within converter1620. In one embodiment parameters1642and/or1624may be a duty cycle of a switching signal of the power extraction, which changes input and/or output impedance matching, which in turn controls the charging and drawing from the internal node. The modification of each parameter can be dependent on the quality of the monitored current and voltage. Controller1640further controls switching device S1626to couple the load to power produced (by converter1622and inverter1624from source1610), when suitably conditioned power is available for use by load1602. In one embodiment, converter1620includes tables1650, which provides a table-based method for controlling power factor, to adjust the operation of converter1620to generate reactive power as desired. The tables may include entries that are obtained based on input conditions measured from the system, to achieve a desired mix of real and reactive power. Feedback from the grid-tied node may include voltage zero crossing, voltage amplitude, and current waveform information. With such information, controller1640uses tables1650to adjust the operation of converter1622and/or inverter1624. The tables may include setpoints that provide idealized output signals the system attempts to create. By matching output performance to an idealized representation of the input power, better system performance is possible than simply attempting to filter and adjust the output in traditional ways. In one embodiment, system1600can be applied without a specific energy source1610. For example, converter1620can be coupled to receive power from grid1630, and generate an output to load1602that provides whatever mix of real and reactive power is needed by load1602. In one embodiment, converter1622can be adjusted to receive AC input. In one embodiment, a connection to converter1622can be configured with hardware to generate DC power from the grid, such as an AC to DC converter. However, it will be understood that such conversion cause some inefficiency. In one embodiment, converter1622can be implemented with an input transformer that will enable connection between grid power and the internal node. FIG.17is a block diagram of an embodiment of a consumer node having intelligent local energy storage. System1700represents a consumer node or an area within a PCC in accordance with any embodiment described herein. System1700specifically shows a configuration where local energy storage is combined with local energy generation at a consumer node. System1700can be or include a DER node in accordance with any embodiment described herein. PCC1710represents an interconnection point to a grid network. Grid power represents power drawn from the grid. In one embodiment, system1700includes gateway1720to aggregate information and control operation within system1700based on the aggregation information. Gateway1720can manage the capacity and the demand for system1700. The capacity refers to the ability of system1700to generate power locally. The demand refers to the load demand locally for system1700, which comes from loads (not specifically shown). In one embodiment, system1700generates capacity with one or more local energy sources1760. Local energy source1760can be any type of energy generation system. In one embodiment, the energy generation mechanisms of local energy source1760generate real power. In one embodiment, local energy source1760represents an energy generation mechanism with an associated power converter and/or inverter. When source1760includes a power converter/inverter, it can be referred to as an energy generation system. Solar power systems are commonly used at customer premises, and source1760can be or include a solar power system. System1700includes one or more energy conversion or power converter devices to control the flow of energy within the PCC. In one embodiment, converter1752and inverter1754represent power converter devices for system1700. In one embodiment, each inverter includes a power converter. In one embodiment, a power converter represents an energy conversion device that enables efficient coupling between a source and a load, such as what is described in reference to system1600. Devices1752and/or1754provide control of the interchange of energy within system1700. In one embodiment, each energy source includes an inverter and/or converter. Thus, the devices represented in the dashed box represent devices that can be spread throughout system1700. Each consumer node can include multiple converter devices for the control of energy flow. In one embodiment, each energy storage resource includes an inverter and/or converter. System1700includes one or more energy storage resources. As illustrated, battery backup system1730represents a system of commercial batteries to store energy. Energy store1740represents a non-battery backup or energy storage device or system, but battery backup will be understood as a specific example of energy store. Examples of non-battery backup can include systems that include a pump or other motorized device that convert active power within system1700into kinetic energy. For example, energy store1740can pump water or other liquid against gravity, can compress air or other gas, can lift counterweights again gravity, or perform some other function to convert energy into work to store in a system. The stored energy can be retrieved later by using a reverse force (e.g., gravity or decompression) to operate a generator. Thus, the energy storage system can convert the kinetic energy back into active power for system1700. In one embodiment, converter1752can be used to charge an energy store (e.g.,1730,1740) when it is depleted or partially depleted. In one embodiment, inverter1754can be used to convert energy from the energy store into active power. Gateway1720can intelligently control the use of energy storage1730,1740. For example, gateway1720can monitor grid conditions to know when the least “expensive” time to charge the energy storage is. Sometimes grid power is less expensive and can be converted into stored energy for later use. Sometimes there is excess capacity from energy source1760that can be stored locally in energy storage1730,1740. In general, in one embodiment, system1700includes local energy source1760, and local energy store1730,1740on a consumer side of PCC1710. System1700also includes a local energy conversion device such as converter1752and/or inverter1754to control the flow of energy to and from the energy storage in system1700. The energy conversion enables system1700to access energy from the energy store and/or to charge the energy store. In one embodiment, system1700charges energy store1730,1740from grid power. In one embodiment, system1700charges energy store1730,1740from energy source1760. In one embodiment, system1700powers a local load to meet local power demand from energy in energy store1730,1740. In one embodiment, system1700transfers power to the grid from energy store1730,1740. The use of stored energy can include the conversion of the energy to any mix of real and reactive power needed for the local load and/or the grid, depending on where the energy is being transferred. FIG.18is a flow diagram of an embodiment of a process for aggregating local and grid-based condition information. Process1800for aggregating local and grid-based information to make a decision based on the aggregation of information can be performed by elements of a control node. In one embodiment, the control node includes a gateway device, which can be or include an aggregator. For simplicity, and not by way of limitation, the description of process1800refers to operations by an aggregator. The aggregator can be in accordance with any embodiment of an aggregator described herein. In one embodiment, the aggregation information includes information gathered by a local meter that measures local and/or external grid conditions. In one embodiment, process1800includes monitoring for local sensors and monitoring for grid condition information. In one embodiment, local sensors register with the aggregator,1802. In one embodiment, the aggregator registers the sensors to configure monitoring the data from the sensors, such as frequency of obtaining data from the sensor, and parameters for interconnecting with the sensor. The aggregator can monitor local conditions by data from the sensors,1804. In one embodiment, the aggregator monitors the sensor until updated information is available. If there is not updated data,1806NO branch, the aggregator can continue to monitor the sensor for local conditions,1804. If there is updated data,1806YES branch, in one embodiment, the aggregator records the condition,1808. In one embodiment, the aggregator also configures itself for interfacing with grid I/O (input/output),1810. The grid I/O can enable the aggregator to receive information about grid conditions from outside the local node of which the aggregator is a part. The aggregator can monitor the grid conditions indicated by the grid I/O,1812. If there is not updated data,1814NO branch, the aggregator continues to monitor the grid I/O,1812. If there is updated data available,1814YES branch, in one embodiment, the aggregator determines whether the grid I/O indicates a condition that needs to be addressed immediately. If there is not an immediate need for action,1816NO branch, the aggregator can record the grid conditions indicated from the external I/O,1808. After recording conditions from the grid and from local sensors, the aggregator can determine to adjust operation at the local control node,1818. In one embodiment, the aggregator makes a determination based on a schedule. In one embodiment, the aggregator makes a determination of what action to take on each data event, where a data event can be when updated data is available. In one embodiment, if data received from the grid needs immediate attention,1816YES branch, the aggregator can determine to adjust the operation of a converter of the control node,1818. In one embodiment, the aggregator applies weights to aggregated data and calculates a state or condition,1820. In one embodiment, the weights can be applied to factor one item of data more than another. In one embodiment where grid information is received requiring immediate attention, the “weight” on that data can be to cause the control node to immediately comply with the request. In one embodiment, the aggregator generates one or more operations to be executed at the consumer node,1822. In one embodiment, the calculation of state and/or the generation of an operation to execute can include the execution of a heuristics decision algorithm that searches a best match output scenario based on the input conditions. The operations can be executed by a power converter of the control node, which can be a device of the control node itself, and/or of equipment within the consumer node. In one embodiment, the operations can include one or more of adjusting real power output for the DER,1824, adjusting a reactive power output for the DER,1826, adjusting both real power and reactive power output for the DER,1828, or providing services to the grid,1830. In the case of providing services to the grid, the services provided can be in response to a market demand. In one embodiment, providing the services will require adjusting operation to provide a different output to satisfy the demand. In one embodiment, satisfying the demand can be performed while continuing to satisfy the demands of a local load. In one embodiment, the system will satisfy the demands of the local load with grid power, to be able to use aggregated generated power to provide market services. FIG.19is a flow diagram of an embodiment of a process for managing distributed energy resources in a grid. Process1900for causing a realtime response from a DER based on market data can be performed by an iGOS system. In one embodiment, the system gathers realtime data for the DERs, which can include local customer demand information and local energy generation,1902. The system also receives realtime market demand information for one or more energy markets,1904. Based on the realtime DER information and realtime market information, the system can compute a best operation for the given conditions,1906. These operations could be referred to as generating and analyzing the data, recognizing that the data can be generated by one or more sensors or other monitoring equipment. Based on what the local DER conditions are and what the current market conditions are, the system can determine if one or more DERs should change operation. If there is to be no change in operation,1908NO branch, the system can continue to gather and analyze realtime data,1902. If there is to be a change in operation,1908YES branch, in one embodiment, the system sends commands to adjust the operation of output hardware of one or more DERs to provide different operation,1910. It will be understood that adjustment to the operation can include adjusting a proportion of real and reactive power from a DER. Thus, the operations can be referred to as modifying output and inject a proportionally determined amount of real and reactive power to obtain the desired operation. The desired operation can provide services to satisfy a market demand, or adjust operation to provide more beneficial local operation based on the conditions of the grid and the local DER. In one aspect, a distributed energy resource (DER) node includes: a hardware interface to gather data from one or more sensors that monitor realtime data for the DER node, including local demand information of loads for a customer premises of a power grid, and energy generation for one or more energy sources of the customer premises; a network interface device to couple over a network to a control center, to provide the realtime data for the DER node to the control center; and grid interconnect hardware to adjust apparent power operation for the DER at a point of interconnection to the power grid, including adjusting real power operation or reactive power operation or both real power and reactive power operation of the DER with respect to the power grid, to provide service to the power grid as a participant with a plurality of other DERs as a single energy market resource in response to realtime market demand for the power grid. In one embodiment, the network interface device is to receive a dispatch control from the control center. In one embodiment, the grid interconnect hardware is to adjust apparent power operation to provide the service, including to provide real power, reactive power, or a combination of real and reactive power from the DER to the power grid. In one embodiment, the grid interconnect hardware is to adjust apparent power operation to provide ancillary services or blackstart services. In one embodiment, the grid interconnect hardware is to adjust apparent power operation to provide non-export services. In one embodiment, the grid interconnect hardware is to adjust apparent power operation to provide one or more of voltage support, VAR support, regulation up, regulation down, frequency support, or demand/response services. In one embodiment, the grid interconnect hardware is to adjust apparent power operation to provide an energy response with either local battery resources or local energy generation resources to provide for at least some of a realtime market demand for the power grid. In one embodiment, the grid interconnect hardware is to adjust apparent power operation including to satisfy local demand with power from the power grid and to provide an energy response with either local battery resources or local energy generation resources to provide at least some of the realtime market demand for the power grid. In one embodiment, further comprising: a four-quadrant energy meter to determine a quadrant of apparent power operation for the customer premises based on inflow or outflow of both real power and reactive power. In one embodiment, the grid interconnect hardware is to adjust apparent power operation including to change a quadrant of apparent power operation in realtime based on market demand for the power grid. In one embodiment, the grid interconnect hardware is to adjust apparent power operation including to change a quadrant of apparent power operation in realtime in response to one or more control signals from the control center. In one embodiment, further comprising: a battery to provide local storage, wherein the realtime data for the DER node further includes a storage capacity of the DER. In one aspect, a method for energy distribution in a grid network includes: aggregating realtime data for multiple distributed energy resources (DERs), including customer demand information of local customers of the DERs and energy generation for the DERs; receiving realtime market demand information for one or more energy markets; and providing a service from a plurality of the DERs as a single energy market resource in response to the realtime market demand. In one embodiment, aggregating realtime data further comprises determining a storage capacity of the DERs. In one embodiment, receiving realtime market demand information comprises receiving a dispatch control from a utility grid operator. In one embodiment, providing the service comprises providing real power, reactive power, or a combination of real and reactive power from one or more DERs to a utility grid. In one embodiment, providing the service comprises providing ancillary services or blackstart services. In one embodiment, providing the service comprises providing non-export services. In one embodiment, the plurality of DERs comprises all of the DERs. In one embodiment, providing the service comprises sending control signals to change an operation of the plurality of DERs. In one embodiment, the customers of the DERs are consumers in the one or more energy markets. In one embodiment, providing the service comprises providing an energy response with customer supply based on the combined data to provide for at least some of the realtime market demand for a utility grid. In one embodiment, providing the energy response with customer supply comprises using customer supply to provide the service while satisfying customer demand with power from the utility grid. In one embodiment, further comprising: computing an ability to satisfy the realtime market demand with combined energy generation of the multiple DERs. In one aspect, an apparatus comprising means for performing operations to execute a method for energy distribution in a grid network in accordance with any of the preceding two paragraphs. In one aspect, an article of manufacture comprising a computer readable storage medium having content stored thereon, which when accessed provides instructions to cause a machine to perform operations to execute a method for energy distribution in a grid network in accordance with any of the preceding two paragraphs. In one aspect, a system includes: multiple distributed energy resources (DERs) including local energy generation resources at customer premises; and a control center coupled to the DERs, the control center including communication hardware to couple to the DERs to receive and aggregate realtime data for the DERs, including local customer demand information of local customers of the DERs and energy generation for the DERs; and processing hardware to compute, based on the realtime data for the DERs and on realtime market demand information for one or more energy markets, a bid to provide services to the one or more energy markets based on an aggregation of the local energy generation of the multiple DERs, with a plurality of the DERs as a single energy market resource. Flow diagrams as illustrated herein provide examples of sequences of various process actions. The flow diagrams can indicate operations to be executed by a software or firmware routine, as well as physical operations. In one embodiment, a flow diagram can illustrate the state of a finite state machine (FSM), which can be implemented in hardware, software, or a combination. Although shown in a particular sequence or order, unless otherwise specified, the order of the actions can be modified. Thus, the illustrated embodiments should be understood only as an example, and the process can be performed in a different order, and some actions can be performed in parallel. Additionally, one or more actions can be omitted in various embodiments; thus, not all actions are required in every embodiment. Other process flows are possible. To the extent various operations or functions are described herein, they can be described or defined as software code, instructions, configuration, data, or a combination. The content can be directly executable (“object” or “executable” form), source code, or difference code (“delta” or “patch” code). The software content of the embodiments described herein can be provided via an article of manufacture with the content stored thereon, or via a method of operating a communication interface to send data via the communication interface. A machine readable storage medium can cause a machine to perform the functions or operations described, and includes any mechanism that stores information in a form accessible by a machine (e.g., computing device, electronic system, etc.), such as recordable/non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.). A communication interface includes any mechanism that interfaces to any of a hardwired, wireless, optical, etc., medium to communicate to another device, such as a memory bus interface, a processor bus interface, an Internet connection, a disk controller, etc. The communication interface can be configured by providing configuration parameters or sending signals, or both, to prepare the communication interface to provide a data signal describing the software content. The communication interface can be accessed via one or more commands or signals sent to the communication interface. Various components described herein can be a means for performing the operations or functions described. Each component described herein includes software, hardware, or a combination of these. The components can be implemented as software modules, hardware modules, special-purpose hardware (e.g., application specific hardware, application specific integrated circuits (ASICs), digital signal processors (DSPs), etc.), embedded controllers, hardwired circuitry, etc. Besides what is described herein, various modifications can be made to the disclosed embodiments and implementations of the invention without departing from their scope. Therefore, the illustrations and examples herein should be construed in an illustrative, and not a restrictive sense. The scope of the invention should be measured solely by reference to the claims that follow. | 143,742 |
11862975 | DETAILED DESCRIPTION The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description. According to an aspect of the invention, an embodiment of a method for transfer of power between medium voltage (MV) feeders via a MV direct current (MVDC) link in a power distribution network is presented with reference toFIG.7. The method is performed in a controller1in the power distribution network. In processing block S100an iteration step value is set for each of a set of power reference quantities of the MVDC link, and an initial value of each of the set of power reference quantities is set. In processing blocks S120and S140values of each of the set of power reference quantities is iteratively changed, and one of the changed values of the set of power reference quantities is iteratively selected. In processing block S120a present value of each of the set of power reference quantities is changed, one at a time, with the set iteration step value, respectively, into a new value, and a total active power at a substation of the power distribution network is measured for each of the new value, one at a time. In processing block S140the new value of the one of the set of power reference quantities that provides the lowest measured total active power at the substation is selected. A next iteration is performed with the selected new value as present value for the selected one of the set of power reference quantities and with the present value for the other of the set of power reference quantities. In optional processing block S110, after the processing block S100, an iteration stopping criterion is set for reduction of total active power. In optional processing block S130, when the iteration stopping criterion has been fulfilled, after the processing block S120, a transfer of power is determined between the MV feeders for the present values of the set of power reference quantities. The iteration stopping criterion may be zero reduction. The iterative step values for the set of power reference quantities may have the same absolute value. The power distribution network may comprise two MV feeders, and the total active power may be active power measured at the primary substation for the two MV feeders added together. The total active power may be measured at one or multiple measurement at the primary substation or below the primary substation, which can indicate the total loss reduction or increase with change in power reference quantity values. The set of power reference quantities may comprise two or more of the following: voltage of a point of common coupling, PCC, for the MV feeders, active power injected by the MVDC link in the PCC for the MV feeders, and reactive power injected by the MVDC link in the PCC for the MV feeders. The set of power reference quantities may comprise at least two of: voltage in a first side of a PCC, voltage in a second side of a PCC, active power in a first side of a PCC, active power in a second side of a PCC, reactive power in a first side of a PCC, and reactive power in a second side of a PCC. Details of the presented embodiment is provided hereafter with reference toFIGS.5to9. An MVDC link connected between two MV feeders is presented with reference toFIG.5. The MVDC link is connected between two different feeders, Feeder1and Feeder2. The MVDC link is illustrated with a back-to-back MVDC link connected parallel to a normally open (NO) switch. However, there may not be a parallel NO switch, and the MVDC link may not be a back-to-back link but rather a point-to-point link with a DC cable in-between the converters. The voltage in the primary substation, VPSS, is measured and so are also the active power fed into the top segment of the two feeders, i.e. P1, P2. Further, at each side of the PCC of the MVDC link, AC voltage, active power and reactive power are measured, i.e. VPCC1, PPCC1, QPCC1for Feeder1and VPCC2, PPCC2, QPCC2for Feeder2. In this example, converter1(i.e., the one connected to Feeder1) is configured for active and reactive power control. Converter2(i.e., the one connected to Feeder2) is on DC voltage control and reactive power control. To reduce power loss in the power distribution network reference values PPCC1ref, QPCC1ref, PPCC2ref, QPCC2ref, should be identified that minimizes losses while keeping other quantities (typically AC voltages and currents) within allowed limits. DC side losses are typically minimized by keeping the DC voltage as high as possible. Thus, PPCC1ref, QPCC1ref, PPCC2ref, remain to be determined. The objective function minPPCC1ref,QPCC1ref,PPCC2refP1+P2 should solved such that various (measured) AC quantities remain within limits. The problem to solve is similar to what would be solved in the optimal power flow (OPF) problem described in the background. However, there are two major differences: Instead of minimizing losses, which cannot easily be measured, the total power fed into the two feeders is minimized. Instead of solving the minimization problem mathematically, it is done by actually changing the reference values in a structured fashion and observing the response in terms of the measured total power fed into the two feeders. If the total active power, Ptot=P1−P2, is reduced as PPCC1ref, QPCC1ref, PPCC2ref, are changed there could be two reasons for this. Either the active losses or the active loads have been reduced. The active losses are mainly resistive losses in the transmission, i.e. I2R losses. The active loads may reduce as a consequence of dependence on voltage magnitudes. However, as long as the voltage magnitudes are kept within the stipulated limits, this should not be a problem. In other words, in practice the sum of active power fed into the feeders can be used as a proxy for active losses. However, it follows that in particular the available voltage measurements should be observed to make sure that the voltage profile is kept in the agreed range. Further, also available current/power measurement should be observed to avoid overloading critical cable segments, in particular in situations when some cable segments are disconnected due to faults and some NO switches are closed to serve all customers. FIG.6illustrates where controller1of the process may be implemented. The controller may be implemented in the primary substation control1a, or in the converter control1b. The controller1may yet alternatively be implemented in a distribution management system (DMS) control (not illustrated). In a DMS implementation the procedure can be executed by the operator of the power distribution network, with measurement of P1, P2, VPSS, and VPCCand communicated (e.g., via SCADA) to a control room and that an operator in the control room then has the possibility to change the set-points or power reference quantities and see the response in total power while keeping voltages within a desired range. Measurements of the voltage in a subsidiary substation (Vsss) may further be communicated to the controller. For implementation in a primary substation control1a, measurements in the PCC VPCCand also of VSSSmay be sent through communication to the primary substation, and the primary substation control1ais allowed to change the MVDC link set-points or power references quantities. For implementation in a converter control1b, measurements in the primary substation P1, P2, and VPSS, and also of VSSSmay be sent through communication to the converter control1b. An embodiment of a method is presented with reference toFIG.8, where one-by-one step change in active and reactive power reference quantities are illustrated in detail to check the change in total active power at the primary substation. The details of changing the reference values to reduce Ptotis presented. In processing block S100a fixed step-size for each reference value, i.e. ΔPPCC1ref>0, ΔQPCC1ref>0 and ΔPPCC2ref>0, is determined. In processing block S110an iteration stopping criterion ΔPtotref≤0, is established such that if ΔPtot>ΔPtotstop, then the minimum total active power has been reached (or at least close enough) for the give step size in reference values. In processing block S120athe current operating point is started with the reference values PPCC1ref,0, QPCC1ref,0, PPCC2ref,0and a measured total power Ptot0. In processing block S120ban iteration step PPCC1ref1=PPCC1ref0+PPCC1refis taken and note through measurement and comparison in processing step S120cΔPtot1=Ptot(PPCC1ref,1, QPCC1ref,0, QPCC2ref,0)−Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,0). In processing block S120dreturn to PPCC1ref,0, QPCC1ref,0, QPCC2ref,0. In processing block S120etake an iteration step PPCC1ref2=PPCC1ref0+ΔPPCC1refand note through measurement and comparison in processing step S12f ΔPtot2=Ptot(PPCC1ref,2, QPCC1ref,0, QPCC2ref,0)−Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,0. In processing block S120greturn to PPCC1ref,0, QPCC1ref,0, QPCC2ref,0. Take an iteration block QpCC1ref1=QPCC1ref0+ΔQPCC1refand note through measurement and comparison ΔPtot3=Ptot(PPCC1ref,0, QPCC1ref,1, QPCC2ref,0)−Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,0). Return to PPCC1ref,0, QPCC1ref,0, QPCC1ref,0. In processing block S120h, check if all reference quantities have been processed. When all reference quantities have not been processed, proceed to processing block S120i. Take an iteration step QPCC2ref2=QPCC1ref0+ΔQPCC1refand note through measurement and comparison ΔPtot4=Ptot(PPCC1ref,0, QPCC1ref,2, QPCC2ref,0)−Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,0. Return to PPCC1ref,0, QPCC1ref,0, QPCC2ref,0. Take an iteration step QPCC2ref2=QPCC2ref0+ΔQPCC2refand note through measurement and comparison ΔPtot5=Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,1)−Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,0). Return to PPCC1ref,0, QPCC1ref,0, QPCC2ref,0. Take an iteration step QPCC2ref1=QPCC1ref0+ΔQPCC2refand note through measurement and comparison ΔPtot5=Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,1)−Ptot(PPCC1ref,0, QPCC1ref,0, QPCC2ref,0). Return to PPCC1ref,0, QPCC1ref,0, QPPC2ref,0. In processing block S120h, when all reference quantities have been processed, proceed to processing block S130. In processing block S13o, when all ΔPtot1, ΔPtot2, ΔPtot3, ΔPtot4, ΔPtot5, ΔPtot6>ΔPtotstopstop the process, as the minimum total active power has been reached. Otherwise proceed to processing block S140to select the reference value that resulted in the lowest power and proceed to processing block S120awith the selected reference value as the new starting point. The step size in reference quantities and stopping criteria may be selected based on network structure, substation power, resolution, and accuracy of the measuring units. It may also depend on what can be detected at the substation based on connected load variations and power flow. A large step size may result in significant changes in power flow while a very small step size may require several steps to achieve the desired value. A large stopping criterion may not reach a very suitable loss reduction while a very small stopping criteria can lead to numerous numbers of steps in reference changes. Once the minimum has been reached, no further actions are required, however as the operating conditions may change, due e.g. to changing loads, the algorithm may be restarted with regular intervals (if the changes in operating conditions are small enough, no steps are actually taken). If one or both converters is/are on AC voltage control the corresponding fixed step in reactive power reference ΔQPCCxref>0 should be replaced with a corresponding step in AC voltage reference ΔVPCCxref>0. There may be natural variations in load, making it harder to distinguish between load variations and the effect of a change in reference values. It is advantageous if the change in reference value and measurement of total power are coordinated in time, such that the step in reference value first is executed and then immediately afterwards, the measurement is performed. Typical step values may be ΔPPCC1ref=300 [kW], ΔQPCC1ref=300[kVar], ΔQPCC2ref=300 [kVar], and may be ΔPtotstop=0, i.e. the algorithm will continue if there a reduction is possible. Initially, all references may be zero. According to an aspect, an embodiment of a controller1for transfer of power between MV feeders via an MVDC link in a power distribution network is presented with reference toFIG.9. The controller1is configured to setting an iteration step value for each of a set of power reference quantities, and setting an initial value of each of the set of power reference quantities, iteratively changing values of each of the set of power reference quantities, and selecting one changed value of the set of power reference quantities by: changing a present value of each of the set of power reference quantities, one at a time, with the set iteration step value, respectively, into a new value, and measuring a total active power at a substation of the power distribution network for each of the new value, one at a time, and selecting the new value of the one of the set of power reference quantities that provides the lowest measured total active power at the substation, wherein a next iteration is performed with the selected new value as present value for the one of the set of power reference quantities and with the present value for the other of the set of power reference quantities. FIG.9is a schematic diagram showing some components of the controller1. A processing circuitry10may be provided using any combination of one or more of a suitable central processing unit, CPU, multiprocessing circuitry, microcontroller, digital signal processing circuitry, DSP, application specific integrated circuit etc., capable of executing software instructions of a computer program14stored in a memory12. The memory can thus be considered to be or form part of the computer program product12. The processing circuitry10may be configured to execute methods described herein with reference toFIG.7or8. The memory may be any combination of read and write memory, RAM, and read only memory, ROM. The memory may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. A second computer program product13in the form of a data memory may also be provided, e.g. for reading and/or storing data during execution of software instructions in the processing circuitry10. The data memory can be any combination of read and write memory, RAM, and read only memory, ROM, and may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. The data memory may e.g., hold other software instructions15, to improve functionality for the controller1. The controller1may further comprise an input/output (I/O) interface11including e.g., a user interface. The controller1may further comprise a receiver configured to receive signalling from other nodes, and a transmitter configured to transmit signalling to other nodes. Other components of the controller1are omitted in order not to obscure the concepts presented herein. The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. | 16,085 |
11862976 | DETAILED DESCRIPTION In demand-response (DR) systems, management of electric power usage by end-user customers can be employed to optimize the demand for electric power with the available supply. To avoid a scenario where the demand for power exceeds the available capacity, or scenarios in which the capacity exceeds the demand (e.g., overproduction of renewable sources) various management techniques have been employed. On the one hand, if the capacity is not able to satisfy the demand, current load balancing techniques simply manage the available capacity received from the energy generating source, and share it across the end-users with extreme situations of load shredding (i.e., blackout) when load requirements cannot be satisfied. On the other hand, if unexpected peaks of power are fed into the power grid, either renewable sources are disconnected from the grid, or consumers are incentive to consume more power. However, these techniques fail to predict faults or conditions that can lead to outages and also fail to prevent over or under-consumption of the available energy resources. There may be a need to intelligently predict fault conditions and reduce or increase energy consumption by flexible resources to mitigate the occurrence of power outages. By introducing predictive fault capabilities for outage conditions in the power grid, the techniques described herein provide benefits through its capability to anticipate possible unwanted situations, and in some cases, even avoid that outages or blackouts conditions occur. Indeed, if a faulty condition is predicted, the aggregator is configured to coordinate the available flexible resources in order to cope with the upcoming situation. In this fashion, the overall quality of the power grids will be improved and the number of local outages can be significantly reduced. Referring toFIG.1, there is shown an embodiment of a processing system100for implementing the teachings herein. In this embodiment, the system100has one or more central processing units (processors)101a,101b,101c, etc. (collectively or generically referred to as processor(s)101). In one embodiment, each processor101may include a reduced instruction set computer (RISC) microprocessor. Processors101are coupled to system memory114and various other components via a system bus113. Read-only memory (ROM)102is coupled to the system bus113and may include a basic input/output system (BIOS), which controls certain basic functions of system100. FIG.1further depicts an input/output (I/O) adapter107and a network adapter106coupled to the system bus113. I/O adapter107may be a small computer system interface (SCSI) adapter that communicates with a hard disk103and/or tape storage drive105or any other similar component. I/O adapter107, hard disk103, and tape storage device105are collectively referred to herein as mass storage104. Operating system120for execution on the processing system100may be stored in mass storage104. A network adapter106interconnects bus113with an outside network116enabling data processing system100to communicate with other such systems. A screen (e.g., a display monitor)115is connected to system bus113by display adaptor112, which may include a graphics adapter to improve the performance of graphics intensive applications and a video controller. In other embodiments, one or more components can be implemented in an embedded device, such as in internet-of-things (IoT) devices. In addition, this can be deployed fully local or deployed partially local and enabled with IoT capabilities. Thus, video, graphics, reporting, etc. ca be performed and/or controlled remotely. In one embodiment, adapters107,106, and112may be connected to one or more I/O busses that are connected to system bus113via an intermediate bus bridge (not shown). Suitable I/O buses for connecting peripheral devices such as hard disk controllers, network adapters, and graphics adapters typically include common protocols, such as the Peripheral Component Interconnect (PCI). Additional input/output devices are shown as connected to system bus113via user interface adapter108and display adapter112. A keyboard109, mouse110, and speaker111all interconnected to bus113via user interface adapter108, which may include, for example, a Super I/O chip integrating multiple device adapters into a single integrated circuit. In exemplary embodiments, the processing system100includes a graphics processing unit130. Graphics processing unit130is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display. In general, graphics processing unit130is very efficient at manipulating computer graphics and image processing, and has a highly parallel structure that makes it more effective than general-purpose CPUs for algorithms where processing of large blocks of data is done in parallel. Thus, as configured inFIG.1, the system100includes processing capability in the form of processors101, storage capability including system memory114and mass storage104, input means such as keyboard109and mouse110, and output capability including speaker111and display115. In one embodiment, a portion of system memory114and mass storage104collectively store an operating system to coordinate the functions of the various components shown inFIG.1. Turning now toFIG.2, a system200for generating DR events based on grid operations and faults in accordance with one or more embodiments is shown. The system200can be implemented in one or more elements of the system100provided inFIG.1. As shown inFIG.2, the system200includes an aggregator202that is in communication with a power grid204and one or more energy management systems (EMS)206. The aggregator202is configured to communicate with the power grid204over a network210and multiple EMS206over network220. In addition, the aggregator202is also configured to communicate with other networks/systems230either directly or indirectly over a network (not shown). The aggregator202is configured to communicate with controllers208of each EMS206that manage energy resource consumption and aggregate the data, individually and collectively, for each EMS206and is configured to compare the aggregated usage with the available capacity. The EMS206includes a controller208to manage the resources that consume energy at a particular customer location. In the example case of commercial buildings, the energy consuming resources that are managed by EMS206can include HVAC systems, chiller systems, batteries, supplemental energy sources such as solar and wind. It is to be understood that other types of systems can be managed by the EMS206and are non-limiting in scope. The systems, equipment, and devices controlled by the EMS206can be classified as either a fixed type or a flexible type of resource. An example of fixed resources includes those energy resources that cannot modify their load consumption/production. Alternatively, an example of flexible resources includes those energy resources that are capable of modulating their power consumption/production within certain operational limits. In one or more embodiments, the resources can operate in a fixed/flexible mode based on various factors such as the time of day or current resources consumption. In other embodiments, the resources can have a priority or a percentage of availability that can be configured in a fixed/flexible mode. In some instances, the EMS206is coupled to systems that can supplement the energy supplied by the power grid204. In this case, the EMS206can reduce or increase the energy resources taken from the power grid204to optimally load balance the available energy resources with the other EMS206in the system200. The supplemental local energy sources include solar and wind energy-based sources. In other instances, the supplemental energy sources can include battery power or other stored energy source, on-site energy sources, or any other device that can be operated to generate or produce energy. Turning now toFIG.3, elements and modules associated with an aggregator300for generating DR events based on grid operations and faults in accordance with one or more embodiments is shown. In one or more embodiments, the aggregator300can be the aggregator202ofFIG.2. The aggregator300includes a communication module302that is configured to communicate with a power grid and multiple EMS systems. The communication protocol can include any suitable wired/wireless protocol to communicate either directly or indirectly over a network to the various devices and systems. In one example, the communication protocol can include an open automated demand-response (ADR) protocol. As shown inFIG.3, the aggregator300also includes a profile module304that is configured to store load profile data such as periods of usage for a particular customers, historical trends, flexible resources, etc. In one or more embodiments, the aggregator300and/or system200can include an anonymizer module (not shown) to protect the identity of the customers. As data is collected and stored for each of the customers the anonymizer module is configured to store the data in a manner that hides or masks the identity of each customer. A baseline or threshold limit for energy usage can be averaged over a period of time and compared to current usage for analysis. The aggregator300is configured to combine all of the usage data to predict how much capacity is available from the power grid. Based on the comparison it is determined if the total demand from each of the EMS is likely to exceed the total available capacity and cause a blackout. In this case, the aggregator300can send messages for each EMS to reduce their demand, for example, if the total demand is within 10% of the total capacity. In addition, the aggregator300can consider whether one of the EMS is over-consuming the energy resources compared to its historical usage patterns. In this case, the aggregator can transmit a message to the particular EMS to reduce its energy consumption or at least reduce its flexible consuming resources. In other embodiments, in the event the aggregator300predicts (or it is noticed by the grid) an increase of renewable energy generation or some alternate source of energy, the power consumption for one or more EMS can be increased. The aggregator300can be configured to send messages to each EMS to increase the power consumption to utilize the excess or surplus amounts of power that was generated to avoid energy spikes. The aggregator300also includes a fault detection module306. Faults can include black-out or brown-out conditions where the demand exceeds the power supply. Faults can also include an overproduction of power where the power supply exceeds the demand which can lead to spikes in power generation. For example, renewable resources such as wind farms, which are weather dependent, can suddenly and unexpectedly increase the power that is generated and lead to fault conditions. In a non-limiting example, a fault at the power grid or supplemental energy sources can be communicated to the aggregator300. In other non-limiting examples, the fault can be determined based on performing calculations to determine whether a capacity of the power grid or alternative energy sources has changed or whether an abnormal consumption at a load has occurred. In other embodiments, the fault detection module306is configured to predict whether an outage condition is likely to occur based on the power grid status and EMS status. In addition, the fault detection module306is configured to predict whether an overproduction condition is likely to occur based on renewable energy source status and the EMS/load status. In the event a fault has been detected or predicted, the aggregator300includes a DR module308that is configured to generate a DR event to transmit to a controller at the load. In one or more embodiments, the aggregator300functions as a load manager to optimize the power usage from the grid. The aggregator300can instruct the load either to reduce/increase power consumption or completely stop power consumption for a period of time. In one or more embodiments, the EMS can instruct its high energy consuming loads to reduce its usage before disabling other lower energy consuming loads. In the event of overproduction of power, such as by the renewable energy sources and/or other energy sources, the aggregator300can instruct each EMS to increase their respective energy consumption to avoid spikes leading to fault conditions. In this example, a windfarm manager can be configured to stop all or part of the wind turbines. In one or more embodiments, the load power can be modulated to increase or decrease its demand based on the predicted fault condition. The aggregator300as shown inFIG.3can also include another module(s)310such as additional hardware and/or software components to add functionality to the aggregator. Furthermore, it should be understood that other configurations and arrangements of the aggregator300can be implemented to manage the system such as the system200shown inFIG.2. Turning now toFIG.4, a flowchart of a method400for generating DR events based on grid operations and faults in accordance with one or more embodiments is shown. It should be understood, the method400can be implemented in any of the systems shown inFIGS.1-3. The method400begins at block402and proceeds to block404which provides for communicating with the grid to obtain the grid status. The aggregator is configured to collect status information for the power grid to determine the current operational performance and capacity. At decision block406, the method400determines whether a fault condition has been reported. The power grid can transmit an existing fault to the aggregator such as a failed generator which reduces the overall available capacity of the power grid. The power grid can also transmit an indication to the aggregator indicating a generator is operating at a reduced level which reduces the overall capacity. The power grid can also indicate if maintenance is to be performed taking a generator offline or any other indication that a change in the production rate of power is to occur. In addition, it is to be understood that any type of status information or message can be provided by the power grid can be processed and used in the method400. In the event a fault has been reported and/or determined, block408provides for the generation of the DR event for notification. Responsive to generating the DR event, the indication is transmitted to one or more EMS indicating that the capacity has been impacted and to reduce the consumption. In one or more embodiments, a single EMS may be tasked with reducing its local resource. In another embodiment, the plurality of EMS may be tasked with reducing its energy consumption in a load balancing manner. In some other embodiments, a negotiation phase among the plurality of EMS and the aggregator may be performed to determine which EMS or combination of EMS will be instructed to adjust their power to achieve a certain level of power reduction. Otherwise, at block408, if no fault condition has been reported at block410the method400provides for forecasting flexible resources, load profiles, and grid production. In one or more embodiments, the flexible resources of each EMS can be stored at the aggregator. The aggregator can also track weather information which can indicate if a storm or other condition that can impact the electric power supplied to each EMS. For example, a severe thunderstorm can take down power lines. High or low wind conditions can impact the production of energy using wind turbines. In another example, overcast or cloudy conditions can impact solar based energy production such as PV panels. In addition, the load profiles for each EMS can be stored at the aggregator to track the usage over a period of time. The usage data can be used to identify trends from each EMS which can be further used to identify abnormal usage. The aggregator is also configured to store the current and historical power grid production rates and capacity. At block412, an optimization-based fault detection and identification is performed. In one or more embodiments, the aggregator is configured to analyze the combination of flexible resources, load profiles, and power grid production to determine whether a fault is likely to occur. The method400proceeds to the decision block414to determine whether a fault is predicted. In the event no fault is predicted, then, as shown at block416, no communication is provided to the EMS. Otherwise, if a fault is predicted, block418provides for generating a DR event for notification to one or more EMS to modify its energy consumption. In one or more embodiments, the method400returns to block404and continues to communicate with the power grid to determine the status. The technical effects and benefits include coordinating available flexible resources based on a predicted fault condition. The technical effects and benefits include improving the overall quality of the power grids and significantly reducing the probability of outages occurring due to reduced grid performance or over-consumption at the loads. As described above, embodiments can be in the form of processor-implemented processes and devices for practicing those processes, such as a processor. Embodiments can also be in the form of computer program code containing instructions embodied in tangible media, such as network cloud storage, SD cards, flash drives, floppy diskettes, CD ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes a device for practicing the embodiments. Embodiments can also be in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into an executed by a computer, the computer becomes a device for practicing the embodiments. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. The term “about” is intended to include the degree of error associated with measurement of the particular quantity and/or manufacturing tolerances based upon the equipment available at the time of filing the application. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. Those of skill in the art will appreciate that various example embodiments are shown and described herein, each having certain features in the particular embodiments, but the present disclosure is not thus limited. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions, combinations, sub-combinations, or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description but is only limited by the scope of the appended claims. | 20,284 |
11862977 | DETAILED DESCRIPTIONS An electrical grid is defined as, among other components, an electrical power system network comprised of generating station(s) (a.k.a. power plant), utilities, substations, feeders, consumer(s), etc. Between the ends (i.e. generating station, consumer), electrical power may flow through substations at various voltage levels. Ideally, this is architected so as to minimize the power loss along the generation-transmission-distribution pathway by maintaining a higher voltage whenever possible. An electric utility is a company within the electric power industry (often a public utility) that engages in any of electricity generation, transmission, and/or distribution as pertains to an electric grid. A distribution utility constructs and maintains the distribution wires connecting the transmission system to the final electricity consumer. Within an electrical grid, substations are a key component of the constitutive generation, transmission, and distribution systems comprising the involved grid. The purpose of a distribution substation is to transfer power from the transmission system to the distribution system of an area. In addition to transforming voltage, distribution substations also regulate voltage (although for long distribution lines, i.e., circuits, voltage regulation equipment may also be installed along the circuits) and isolate faults. Several distribution substations (DS) may comprise a distribution utility. “Feeders” represent the power lines through which electricity is transmitted within power systems. A distribution feeder represents one of the circuits emanating from a DS, and it transmits power from a DS to the designated distribution points serving electricity to the consumer. Typically, there are several distribution feeders per DS. A feeder may segue into primary and/or lateral distribution lines which carry medium voltage power to distribution transformers located near the electricity consumer. Distribution lines may include two or three wires which carry, respectively, two or three phases of current. A transformer is an electrical device consisting of two or more coils of wire that transfer electrical energy between two or more circuits by means of a varying magnetic field (a varying current in one coil of the transformer produces a varying magnetic flux, which, in turn, induces a varying electromotive force across a second coil wound around the same core). A distribution transformer provides the final voltage transformation within an electric power distribution system. The electricity consumers are served with single-phase power in the form of secondary distribution lines (SDLs) which carry lower voltage power to the electricity consumer. As used herein, the concept of locality or proximity in an electrical grid may refer to: (1) physical proximity, e.g., the distance between items in the real world; (2) network proximity, e.g., the number of communication links between items and/or the transmission times associated with such communication links; (3) grid proximity, e.g., the number and type(s) of electrical distribution devices between items; and/or (4) combinations thereof. For example, two given secondary lines may be located in close physical proximity (for example on adjacent streets) but be considered to have a larger distance due to an elongated grid proximity if they are supplied by different primary distribution lines or substations. Under a conventional or prototypical HQ C2 Architecture, the substantive portion of data (e.g. Non-Operational Data, Situational Awareness Data) is often not utilized; paradoxically, this information is particularly vital under exigency circumstances. By way of example, data is often classified into various data categories by performance needs: “Non-Operational Data” may be more historical and forensic in nature; “Situational Awareness Data” may be useful for further appraising operational data, but it has not yet been fully integrated with Operational Data; “Operational Data” is indicative in nature and used for decision-making, and may provide the immediate performance expected of quasi-real-time data. For example, the grid may operate a supervisory control and data acquisition (SCADA) system which operates as a conventional C2 network. For example, an electrical utility may utilize phasor measurement unit (PMU) data, weather data, meter data (measuring individual customer usage or aggregated usage in an enclave), electricity market data, SCADA, and Digital Fault Recorder (DFR) data in monitoring the grid, state estimation, event detection, and control operations for distributing electricity throughout the grid. Each of these types of data may be generated and/or received at different frequencies. For example PMU data may be sampled at a distribution point in the grid at 512 times per cycle, which in a typical 50 or 60 Hz AC system (i.e., 50 or 60 cycles per second, respectively), is in the range of about 103Hz-104Hz. At the other extreme, market pricing of electricity may only be generated a few times a day, such as once per hour during business hours, for sampling frequency on the order of 10−4Hz. Other examples include weather data sampling up to about 1 Hz and meter data sampling up to about 10−2Hz (e.g., around 1 sample per minute or two). Evident from these examples is that the volume of data generated from each source over a given time period varies significantly; accordingly, the transfer, storage, and analysis of higher-resolution data (such as PMU data) to a central HQ C2 node may be impractical. Furthermore, the different types of data may not be supplied to and/or generated at each node in the grid. For example and without limitation, pricing may be sampled at a single headquarters node, weather and PMU data sampled at substations, and meter usage sampled at the transformer level. In application, DFR data is construed as non-operational data and can, over time, be used to take corrective action, thus contributing to a historical model. PMU data has the highest resolution, is the most voluminous, and is more predictive and real-time, but is considered situational awareness data because the SCADA system, generally operating at a lower time resolution, is used operationally. Likewise, weather data and sensors can be used as situational awareness data. As described herein, a “state input” or “state data” may refer to the quasi-real-time operational data of an electrical component device or group of devices, or even the entire electrical grid. Under exigency situations, this traditional solitary command network quickly devolves as “partner” nodes are often needed. If the exigency is limited, only one “partner” enclave may be needed. However, if the exigency is large-scale and widespread, the needs may be varied, and, consequently, multi-partner enclaves (MPE) may be needed. Accordingly, during non-exigency situations, the HQ C2 can function in a certain way; yet, during certain exigency situations, the involved HQ C2 architecture must be able to devolve into an MPE structure. Preferably, during non-exigency situations, the partners and/or partner candidates within the network continuously update and tune their internal decision systems as both real-time operational data and the commands and system adjustments from the HQ C2 are received. Thus, over time, the normal operational preferences of the utility operator and/or the HQ C2 node may become embedded in the historical baseline model and the heuristic model implemented at each of the MPE partner nodes. Accordingly, even when the hierarchical command structure devolves into the MPE network, the interests of the original HQ C2 remains prominent in managing each partner's enclave. As discussed herein, the heuristic model is a predilection formed at a hyper-local level in an MPE given an accumulation of Non-Operational Data, Situation Awareness Data, and Operational Data experiences. Based on this repertoire of data at the local level, the ambiguity in any situation may be lowered, providing a quick decision based on the preformed deep beliefs embedded in the model. Referring toFIG.1, an electrical grid100is illustrated which can be represented as a network of nodes, with command node110in communication with at least substation nodes120a,120b, and120c. As illustrated, the substation120asupplies electricity to feeders122a,124a,126a, which be primary distribution lines, lateral distribution lines, or secondary distribution lines, as discussed above, and may include transformer(s) at appropriate locations. Similarly, substation120bsupplies feeders122b,124b,126b, etc., and substation120cmay be similarly arranged (not shown). In some instances, the distribution system may be such that a given feeder may be, directly or indirectly, within the downstream distribution network of two substations, such as feeder128. InFIG.1, each of the substations and feeders may be considered distribution nodes within the domain of the electrical grid. In a prototypical command structure, under non-exigency circumstances, the command node110may have direct interaction with subsidiary nodes such as substations120a,120b,120c, for example via a fiber optic communications network, which may relay commands through preset hierarchical pathways to the nodes and equipment further downstream in the distribution system as in a traditional SCADA system. It is understood that in other embodiments (not shown), the command node may be in direct communication with subsidiary nodes which are not substations, and the non-limiting example inFIG.1is for purposes of illustration only. FIG.2illustrates a multi-partner enclave (MPE) decision system200derived from the structure ofFIG.1. As seen inFIG.2, the command node110is eliminated from control hierarchy, as indicated by the dashed lines. This situation may occur in the event of an outage or other exigency condition. The decision system may be configured to identify localities of distribution nodes such as groups or enclaves230aand230b, shown in dotted lines. The command functions of the system then may devolve to partner nodes elected from each of the enclaves230aand230b. For example, the substations120aand120bmay serve as partner nodes for enclaves230aand230b, respectively. (For ease of illustration, substation120cis omitted fromFIG.2and subsequent drawings.) The system may define new hierarchical communication pathways from each of the partner nodes to its respective locality of distribution nodes. InFIG.3, a substitute command node310is inserted into the variant system300derived from the systems ofFIGS.2and1. As seen inFIG.3, substitute command node310may distribute commands to the node network through former partners of the MPE network (such as, for example, substations120aand120b) and/or be in direct communication with nodes further downstream (such as, for example inFIG.3, feeder126aand its downstream nodes such as feeder128). More specific decision methods implemented within the command and/or partner nodes are illustrated inFIG.4. The decision support engine400counterbalances uncertainty with ambiguity. Under tight time constraints, it accepts higher uncertainty (i.e., sparse data) given the condition of lower ambiguity (this situation occurs before in the historical data). Conversely, if there is higher ambiguity (this situation does not occur historically), the system does not accept higher uncertainty; instead, it uses more data to lower uncertainty. Hence, the Lower Ambiguity, Higher Uncertainty (LAHU) and Higher Ambiguity, Lower Uncertainty (HALU) decision paradigms are embedded in the decision engine. By way of explanation, input data401is ingested by two disparate pathways: (1) uncompressed decision cycles (UDC), and (2) compressed decision cycles (CDC). InFIG.4, up to decision step470, the uncompressed decision cycle path is shown in solid lines, and the compressed decision cycle path is shown in dashed lines. The two paths merge at decision step470. For UDC (solid lines), the data is passed to the Non-Operational Data (e.g. historical baseline) module410as well as a HALU model420(i.e. more data is desired). Accordingly, in the UDC path, a series of state data and/or data from multiple sources may be ingested. In contrast, for CDC (dashed lines), data will be passed to the Deep Belief Heuristics module415and a LAHU module425. The LAHU module425may be a near pass-through algorithm providing for minimum computation time via numerical method accelerants. For the UDC pathway, the historical baseline module410and HALU420pass their votes to a modified Q-Input Voting Algorithm (QIVA) module430, whose output is then optionally passed along to a Quantitative Definiteness or Quantitative Exactitude Algorithm for Fault Tolerant Systems (QEAFTs) variant step450for further processing prior to a decision470being reached. (A Q-Input Voting Algorithm is a variant of various N-Input Voting Algorithms, for example as described in A. Karimi, F. Zarafshan, and A. Ramli, “A Novel N-Input Voting Algorithm for X-by-Wire-Fault-Tolerant Systems,” The Scientific World Journal, October 2014. A QEAFT may be a variant of voting algorithm employing a comparator threshold, for example as described in S. Latif-Shabgahi, “An Integrated Voting Algorithm for Fault Tolerant Systems,” 2011 Intl. Conf. Software and Computer Apps., Intl. Proc. of Comp. Sci. and Inf. Tech., Vol. 9, pp. 1-17, 2011.) For the CDC pathway, the heuristics module415and the LAHU425pass their votes down a fast track pathway that has its own voting module440, and optionally an additional “Lower Ambiguity Accelerant (LAA)” step460comparing to an output of the historical model410. As seen inFIG.4, the QEAFT step450may consider the output of the CDC voter440. A resultant decision470may be selected based on the available decision cycle time, communicated to the network in the sending command step480, and implemented by adjusting an apparatus step490in the electrical grid. FIG.5illustrates a process500for developing an MPE structure for use in the systems and methods described above. The method functions in a domain of nodes within the electrical power grid. As illustrated, the method includes step510of identifying node subsets within the domain. The subsets may be selected based on proximity, including physical and/or grid proximity as discussed above. Preferably, subsets are selected to generally correspond with substations or a proximate group of feeder lines serviced by a single substation. In step520, a partner node is elected for each subset group. Again, such election or selection may be based on proximity to the subset of grouped nodes. In optional step530, key nodes in the domain may be identified. Such key nodes may service a comparably large number of customers, or for example may service particular prioritized types of customers of critical importance, such as hospitals, traffic signals, or airports. In step540, the historical and/or heuristic models are built based on a historical set of non-operational data and/or situational awareness data. In step550, the partner node receives operational data and/or situational awareness data from its node subset. This data is used to update and/or tune the models in a return to step540as well as passed to evaluation step560, which may proceed according to the methods described above in connection withFIG.4to identify an adjustment an electrical property in the subset nodes. In step570, the partner node sends a command to one of the other nodes in the subset. In some embodiments, the command is sent directly to a key node for adjustment of an electrical device at the key node. Optionally, a new headquarters node may be introduced at step580and provide additional commands and/or data to the partner node in step550. In addition to sending the adjustment command, the process can return to receiving operational data and commands in step550, thereby continuously updating the decision models and evaluating the system state for potential adjustments. Performance indices of electricity supply services system reliability include the following: System Average Interruption Frequency Index (SAIFI) (the average number of interruptions that a customer would experience during the measurement period); System Average Interruption Duration Index (SAIDI) (the average duration of interruption for each customer served during the measurement period); Momentary Average Interruption Frequency Index (MAIFI) (the average number of times a customer experiences a momentary interruption during the measurement period); and Customer Average Interruption Duration Index (CAIDI) (the average length of a sustained customer interruption during the measurement period), which may be calculated simply as SAIDI divided by SAIFI. Among the discussed indices used to measure distribution system reliability, the System Average Interruption Frequency Index (SAIFI) can be calculated as shown: SAIFI=∑NiNT where Ni=Total number of customers interrupted for each sustained interruption event and NT=Total number of customers served. Another index is System Average Interruption Duration Index (SAIDI), which can be calculated as shown: SAIDI=∑(ri×Ni)NT where ri=Restoration time (in minutes), Ni=Total number of customers interrupted for each sustained interruption event, and NT=Total number of customers served. Another index is Customer Average Interruption Duration Index (CAIDI), which can be calculated as shown: CAIDI=∑(ri×Ni)∑Ni where ri=Restoration time (in minutes) and Ni=Total number of customers interrupted. As Niplays such an instrumental role with regards to the SAIFI, SAIDI, and CAIDI calculations, it is important to examine the key distribution utility components affecting Ni. The identification of key nodes based on number of customers served is thus a useful metric for selection of key nodes for increased monitoring and management and/or weighting in decision systems and methods. By comparison, in a conventional command structure, the key nodes may be identified by manual input without a rigorous evaluation of the true impacts on performance indices, leaving the entire involved distribution network exposed and perpetuating a misunderstanding of how to best react during an outage or other exigency event. For example, consider an exemplary electrical grid with two distribution substations DS1 and DS2 and six feeders F1-F6 serviced by the substations with the customer counts in Table 1: TABLE 1FeederDS1DS2F1800F25000F3715F48050F51250F63000Total173001515 In Table 1, NT=17300+1515=18815. In a traditional command structure, there is a natural tendency to select the substations as key nodes. However, in the example of Table 1, a failure of DS2 would provide a SAIFI score of 1515/18815=8.05%. On the other hand, failure of feeders F2, F4, or F6 would have SAIFI scores of 56.72%, 42.79%, and 15.94%, respectively, substantially greater than the interruption impact of a failure of substation DS2. Similarly, the feeder F5, although supplied by substation DS1 like the other impactful feeder nodes, supplies a relatively smaller number of customers and has an even lower SAIFI score than DS2 (6.64%). Accordingly, monitoring and prevention resources may be better spent in designating feeders F2, F4, and F6 as key nodes rather than DS1, DS2, or F5. (Of course, as described above, there may be other considerations that would justify designating DS2 and/or F5 as a key node, for example supplying a local hospital or other prioritized infrastructure.) As seen above, the interruption durations rialso affect the SAIDI and CAIDI equations. It should be noted that the example of Table 1 is simplified from a real-world implementation, which may involve dozens or a few hundred of distribution transformers with varying customer counts to service a similar population size, and the key nodes may be selected from multiple levels of the distribution architecture, including substations, feeders, transformers, and/or combinations of components. Additional improvements may be achieved by delegating key node identification to the local partners in an MPE network to select more impactful nodes within given enclaves, and accordingly enhancing the monitoring and control activities directed to such local key nodes. Oscillation events are one of the major issues within a power system which can damage equipment at node sites within an electrical grid, leading to collapse of an entire transmission system in some situations. Oscillations can be in various forms, such as natural oscillations, electromechanical, transient oscillations, and forced oscillations. For example, synchronous machine generation equipment in power plants may introduce harmonics into the power system and cause oscillations, typically in a frequency in ranges around 0.2-4 Hz. On the other hand, subsynchronous oscillation events around the frequency range 10-100 Hz may occur, for example, as the result of interactions between transmission networks and some controllers for renewable energy sources. Traditional PMU equipment may not have sufficient resolution to measure interharmonic phasors to detect some types of oscillation events. For example, a standard PMU device may have a sampling rate of 60 Hz, but for monitoring purposes this equates, at best, to about 30 Hz and often as low as 15-20 Hz due to data errors and filtering algorithms in current equipment. Subsynchronous oscillation detection units (SSODU) may be used instead of or in addition to traditional PMU devices to provide multi-resolution data sources and sampling frequencies. FIG.6shows a block diagram for a method600or high-resolution sampling and detection of harmonic oscillation instabilities. In step605, voltage sampled at a node is mapped against time values on a scale of milliseconds, for example data acquired from a PMU or more preferably an SSODU. Anomaly detection proceeds in step615by comparing the waveforms to expected values of the operating grid (e.g., 60 Hz), waveforms and data acquired from different devices in the grid (e.g., different channels), and/or historical models of the system behavior. In optional step620, an alert message may be provided to system operators or command nodes in parallel to further processing and analysis. For example, an alert may be sent if the anomaly is an abrupt change in operating state even though additional information about the anomaly is not yet available. Once identified, anomaly events can be traced to particular devices and/or grid locations in further processing steps. Optionally, data samples can be provided to analysis engine for updating model in step610even if an anomaly is not detected and subjected to further analysis. In step625, further measurements are captured starting from the first peak of the detected oscillation. For example, the local oscillation may have frequencies around the range of 0.1 Hz to 2 Hz, such that one cycle of the oscillation event can be captured in about 10 seconds (i.e., if the frequency is 0.1 Hz). The captured data may then be subjected to further analysis and processing in step635, which may take a variety of forms. In one embodiment, analysis635includes application and retraining of a deep learning engine based on a convolutional neural network (CNN), which is further discussed in connection with and illustrated inFIG.7. Analysis635may include additional data analysis methods known to those of skill in the art to provide rapid analysis and categorization of a subject analysis event in place of or in addition to the techniques inFIG.7. This rapid response time improves overall grid resiliency. For example, to maintain interoperability of a power generation utility and a distribution utility, the generation utility may need to shed many megawatts of power within one minute of the anomaly in order to prevent successive events caused by the oscillation at the distribution utility, such as equipment failures. The causes or sources of an oscillation event are then reported to a command node or partner node in step645, and these reports can be used for overall system command and control processes as described above in connection withFIGS.1-5. InFIG.7, a detailed view of the modeling process700is shown, which may be applied in step635ofFIG.6alone or in combination with other computational processes. Training dataset710may be time series of data from PMU or SSODU devices and may include additional data types such as weather or other forms of Non-Operational Data, Situation Awareness Data, and Operational Data discussed above. In a forward-propagating step720, the initial training is performed based on the training data input710to produce a model730. Pertinent features of the data can be extracted from the model in step750, which are then used to develop a classifier760. As new data740is received, it is evaluated in relation to the model730and proceeds through feature extraction750and classification760. That result may then be used to update the model730in back propagation step770. Such an analysis/CNN engine may be implemented at an individual node, a partner node supervising a subset of nodes, or even at a command node aggregating data from many nodes and/or enclaves in the grid system. The model730may be continuously updated such that upon detection of an oscillation event, the new event can be rapidly classified according to the pre-built classification760. In a preferred embodiment, model730is a convolutional generative adversarial neural network (CGANN) algorithm. The CGANN is a combination of generative adversarial networks (GAN) and convolutional neural networks (CNN). A GAN model consists of two different neural networks; a generator G is often represented as (z), and a discriminator D is often represented as (x). The generator G is responsible for the generation of data, and the discriminator D functions to ascertain the quality of the generated data and provide feedback to generator G. Through multiple cycles, the generation and discrimination network train each other. D is trained to maximize the probability of assigning the correct label to both training examples and samples from G, and G is trained to minimize log (1−((z))). The GAN approach has a number of advantages, such as the fact that the learning process does not take a great deal of time, as GANs do not require label data, and the generated data is similar to real data; accordingly, there is an inherent ability to learn complicated distribution data (grouping or the density of the observation). The generator network and discriminator network for a GAN can be any of the neural network types. In the preferred implementation of the present disclosure, the CNN is used for a convolutional adversarial neural network (CANN). CNN has shown excellent performance for several applications, such as object detection, medical analysis, and image classification. The basic concept of CNN is to obtain local features from input at higher layers and combine them into more complex features at lower layers. To optimize the network structure and solve the unknown parameters, CNN utilizes the back-propagation algorithm. CNN is usually utilized on visual data, and if CNN is utilized on non-visual data, it is necessary to encode the data in a way that mimics the properties of visual data. CANN networks utilize convolutional layers within the generator network and discriminator network of GAN. A CANN system is a network with convolutional layers, followed by normalization or pooling layers and an activation function. In the CANN, the discriminator network takes the data and downsamples it with the assistance of convolutional and pooling layers and then utilizes a dense classification layer to predict the data. The generator network takes a random noise mechanism, and finally generates the data. A fully convolutional network is a network without fully connected dense layers at the end of the network. Instead, it consists of convolutional layers and can be end-to-end trained, such as that of a convolutional network with fully connected layers. There are no pooling layers in a generator network, while the discriminator network has fully connected layers with a classifier at the end of the layer. The results of the CGANN may be used as a feature extractor750to derive key features from the input data which are then fed into a classifier760. Preferably, classifier is a nonlinear support vector machine (SVM) classifier. SVM is a widely accepted supervised machine learning technique that is used for either classification or regression. SVM has the ability to ascertain the unknown relationship between a set of input variables and the output of the system, can be trained with quadratic programming (QP) and exhibits good learning ability for small samples. SVM can also leverage the structural risk minimization (SRM) principle to minimize the training error. The output from the feature extractor may fed into the nonlinear SVM model as inputs, while the pre-trained CNN is utilized as a starting point for new input data using a nonlinear SVM classifier. Utilizing the pre-trained CNN model, the transfer learning mechanism facilitates enhanced accuracy for new tasks. The CNN and finely tuned SVM amalgam can effectively handle nonlinear complexities and short-term dependencies of the electrical time series data. It will be appreciated by those skilled in the art that the resilient decision systems and methods provided by this disclosure are not limited to the specific grid configurations shown in the figures or described herein, but rather that the inventions may be adapted to provide many additional power grid configurations with enhanced reliability and resiliency. | 29,881 |
11862978 | DESCRIPTION OF EMBODIMENT An exemplary embodiment of the present invention is described below with reference to the drawings. However, the exemplary embodiment described below shows an example of the present invention, and the present invention is not limited to the following example. Further, in the present specification, components shown in the claims are not limited to the components of the exemplary embodiment. In particular, it is not intended to limit the sizes, materials, and shapes of components and relative arrangement between the components, which are described in the exemplary embodiment, to the scope of the present invention unless otherwise specified. The sizes and the like are mere explanation examples. However, the sizes and the positional relation of the components in each drawing are exaggerated for clearing the explanation in some cases. Furthermore, in the following description, the same names or the same reference marks denote the same components or the same types of components, and detailed description is therefore appropriately omitted. Further, regarding the elements constituting the present invention, a plurality of elements may be formed of the same component, and a single component may serve as a plurality of elements. To the contrary, the function of a single component may be realized by a plurality of components in cooperation. Hereinafter, as an example of a power supply system according to an exemplary embodiment of the present invention, an example is described in which the present invention is applied to a large-scale power storage device to be used for a natural energy power plant and the like such as solar power generation and wind-power generation. This power storage device once stores electric power generated by solar power generation or wind-power generation and then supplies the electric power to power system ES. FIG.1is a block diagram showing power supply system1000according to an exemplary embodiment of the present invention. Power supply system1000shown in this drawing includes a plurality of power supply units10and control system100to which these power supply units10are parallel connected. Control system100includes power conditioner140, system controller160, and master controller (M-BMU)120. (Power Supply Unit10) Each power supply unit10includes battery aggregation11, unit controller (BMU)12, and switch14. In each battery aggregation11, a plurality of battery modules1are series and parallel connected. Further, each battery module1is configured with a plurality of series and parallel connected secondary battery cells. (Unit Controller12) Unit controller12is connected to battery aggregation11and acquires battery information relating to electric power at which battery aggregation11can be charged and discharged. Unit controller12is connected to master controller120and outputs the battery information. Here, the battery information represents conditions of battery aggregations11(or battery modules or secondary battery cells constituting battery aggregations11) included in power supply units10, for example, internal resistances, voltages, currents, SOCs, degrees of degradation, temperatures, and the like. (Switch14) Switch14is a component for switching connection and disconnection between each power supply unit10and power conditioner140. In the example ofFIG.1, switch14is disposed between battery aggregation11and power conditioner140and is switched on and off by unit controller12. Switch14may be separately disposed in a charging direction and in a discharging direction. In this case, the switch includes a charge switch and a discharge switch. Then, the power conditioner turns off the charge switch of a power supply unit whose chargeable individual power has become 0, and turns off the discharge switch of a power supply unit whose dischargeable individual power has become 0, among the power supply units. (Control System100) On the other hand, control system100includes power conditioner140, system controller160, and master controller120. Regarding these components, instead of preparing individual components as shownFIG.1, arbitrary components can be integrated into one body. (Power Conditioner140) Power conditioner140is parallel connected to switches14of power supply units10. Further, power conditioner140is connected to a power system. Power conditioner140receives electric power from the power system to charge power supply units10, and conversely receives electric power from power supply units10to discharge the electric power to the power system. (System Controller160) System controller160is a component to communicate to power conditioner140electric power of charging and discharging required to power supply system1000as a power command. System controller160receives a power command value, for example, through communication with a high-order system or an external device. Alternatively, system controller160may be configured to autonomously generate a power command value. (Master Controller120) Master controller120is connected to unit controller12of each power supply unit10to collect information (battery information) about a battery condition of each power supply unit10. Further, master controller120determines a possible total power SOPall at which all power supply units10can be charged and discharged on the basis of the collected battery information. On the basis of the possible total power determined by master controller120, power conditioner140inputs and outputs electric power for charging and discharging, from and to power supply unit10. In this control system100, system controller160communicates a power command to power conditioner140. On the other hand, master controller120sends out the battery information from each of unit controllers12to power conditioner140. Power conditioner140receives this information and determines a possible total power SOPall (hereinafter, also referred to as a “total SOP”) at which all power supply units10can be charged and discharged on the basis of the battery information sent out from master controller120. On the other hand, the power deviation among power supply units10is detected, and a working total power POBall (hereinafter, also referred to as a “total POB”) is determined on the basis of the power deviation, where the working total power POBall is a summation of electric power at which each power supply unit10is charged and discharged, and charging and discharging are then performed on power supply units10at the total POB. Since the charging and discharging are performed at the total POB, a working individual power POBn, which is an individual charging and discharging power for each power supply unit10, is determined (the power deviation will be described later in detail). Note that the possible total power and the possible individual power may be determined by the master controller or the unit controller other than by power conditioner140. For example, the unit controller determines the possible individual power of the power supply unit on the basis of the battery information of the battery aggregation connected to the unit controller. In the example ofFIG.1, unit controllers12of respective power supply units10calculate a possible individual power SOP1 of power supply unit10#1, a possible individual power SOP2 of power supply unit10#2, a possible individual power SOP3 of power supply unit10#3, and a possible individual power SOP4 of power supply unit10#4. On the basis of the thus calculated possible individual power of power supply units10, the possible total power SOP is calculated by master controller120. Further, master controller120and unit controllers12control turning on and off of switches14such that, if the SOP is 0 or abnormality has occurred in one of power supply units10, the one of power supply units10is separated from power conditioner140. By this operation, even if certain power supply unit10stops or the SOPn has become 0, an appropriated power control operation is ensured. (Power Control Method By Power Supply System Relating to Comparative Example) Here, a description is given to electric current control on the power supply unit in a power supply system according to the comparative example. In the power supply system relating to the comparative example, a chargeable and dischargeable maximum power is calculated for each power supply unit. Then, from the SOPn of each power supply unit, the total SOP is calculated and is communicated to the power conditioner. For example, the possible total power SOP can be expressed by the following equation, where a number of the connected power supply units is n. Possible total power SOP=(minimum SOP of SOPn)×(connection number of power supply units being connected to the power conditioner) Equation 1 With this arrangement, even when the possible individual power SOP of a certain power supply unit becomes low, the electric power can be kept to the minimum SOP or smaller. In other words, with respect to each power supply unit, POBn≤SOPn holds. (Power Deviation) Equation 1 holds appropriately when there is no power deviation occurring among the power supply units. However, in practice, the possible individual power of each power supply unit depends on a battery condition and is not necessarily constant. Therefore, among the power supply units, there occurs a variation in a possible individual power, in other words, a power deviation. As a result, in the power control based on the above-described total SOP, POBn≤SOPn may not hold for a certain power supply unit, and a rating or an individual SOP may be exceeded. In this case, there is a concern that the power supply system may stop due to an abnormal current or other causes. To address this issue, in the present exemplary embodiment, charging and discharging control is performed in view of such a power deviation. Here, in order to describe a problem caused by a power deviation, a discussion is made on a power supply system as the power supply system relating to the comparative example, in which four power supply units310#1to310#4are connected to common power conditioner340as shown inFIG.3.FIG.4shows conditions of the battery modules at the time of the power control by which power supply units310are charged and discharged. In this table, among condition numbers 1 to 8, there are differences in the power commands sent from system controller160, and the battery conditions, possible individual power, and the like of the battery modules. In the upper columns ofFIG.4(condition numbers 1 to 4), there is no power deviation occurring among power supply units310#1to310#4, in other words, the columns show the conditions of the battery modules in which a ratio of the possible individual power of power supply units310is 1:1:1:1. On the other hand, in the lower columns ofFIG.4(condition numbers 5 to 8), there are power deviations occurring among power supply units310#1to310#4, and the columns show the conditions of the battery modules in which the current ratio of power supply units310is 5:4:4:3. Note that the power command and the total SOP are made to correspond to one another between condition numbers 1 to 4 and condition number 5 to 8. (Comparative Example: When There is no Power Deviation) InFIG.4, for example, in the case of condition number 1, with respect to the possible individual power SOP1 to SOP4 of power supply units310#1to310#4, a dischargeable individual power SOP representing a dischargeable electric power (hereinafter, also referred to as a“discharging SOP”) and a chargeable individual power SOP (hereinafter, also referred to as a“charging SOP”) representing chargeable electric power are both 60 kW. Therefore, the minimum SOP of SOPn is calculated to be 60 kW according to Equation 1, and a possible total power SOPall for all power supply units310#1to310#4is 60 kW×4=240 kW for both of discharging and charging. In addition, the power command sent from system controller160is 160 kW and is within the possible total power SOPall, and the working total power POBall can be 160 kW, which is the same as the power command. Therefore, this power command can be executed. Further, the working individual power of each power supply unit310is 160 kW×1/4=40 kW. Here, since the possible individual power SOP1 to SOP4 of power supply units310are each 60 kW for both of the discharging SOP and the charging SOP as described above, the working individual power of 40 kW can be dealt with, and POBn≤SOPn thus holds. Similarly, in the case of condition number 2, as is the case with condition number 1, the possible total power SOPall is 60 kW×4=240 kW for both of discharging and charging. In addition, since the power command is 240 kW, the workable electric power POBall is similarly 240 kW, and each working individual power is 60 kW. Here, since the possible individual power of each power supply unit310is 60 kW for both of the discharging SOP and the charging SOP, the working individual power of 60 kW can be dealt with, and POBn≤SOPn thus holds. On the other hand, in the case of condition number 3, the possible individual power SOP of each of power supply units310#2to310#4is 60 kW for both of the charging SOP and the discharging SOP as is the case with condition numbers 1 and 2. In addition, power supply unit310#1is in a fully-charged condition or in a condition in which charging is prohibited for some reason, and the discharging SOP and the charging SOP are respectively 60 kW and 0. Therefore, discharging is possible; however, at the time of charging, switch14is turned off to be separated from power conditioner140, and power supply unit310#1is not charged. In this condition, the possible total power SOPall at the time of charging is 60 kW×3=180 kW. Here, if the power command for charging is 240 kW, the power command is greater than the possible total power SOPall; therefore, the working total power POBall is limited to 180 kW. Further, regarding the working individual power of each power supply unit310, power supply unit310#1is separated from power conditioner140and is thus not an object of charging; the working individual power POB2 to POB4 of power supply units310#2to310#4each are 180 kW×(1/3)=60 kW. Moreover, in the case of condition number 4, regarding possible individual power SOP for each of power supply units310#2to310#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition numbers 1 to 3, but power supply unit310#1is being charged with a constant current or is in a condition in which the charging power is set lower than other power supply units310#2to310#4because of some reason. Thus, the discharging SOP is 60 kW, but the charging SOP is 20 kW. In this condition, since the minimum SOP at the time of charging is 20 kW, the possible total power SOPall is 20 kW×4=80 kW according to Equation 1. Here, if the power command is 240 kW, the power command is greater than the possible total power SOPall, and the working total power POBall is therefore limited to 80 kW. In addition, the working individual power for charging each of power supply units310#1to310#4is 80 kW×1/4=20 kW. On the other hand, regarding the possible individual power of each power supply unit310, the discharging SOP of each power supply unit310is 60 kW, the charging SOP of power supply unit310#1is 20 kW, and the charging SOP of each of power supply units310#2to310#4is 60 kW. Therefore, every power supply unit can deal with working individual power of 20 kW, and POBn SOPn thus holds. Note that when battery aggregation11is in a constant current (CC) charging and discharging region, the charging SOP and the discharging SOP are normally both at their maximums. (Comparative Example: When There is Power Deviation) As described above, in the condition in which there is no power deviation among power supply units310, charging and discharging power control can be appropriately performed in any of the cases of condition numbers 1 to 4. Next, a discussion is made on condition numbers 5 to 8, in which the power deviations among power supply units310#1to310#4are represented by a current ratio of 5:4:4:3. Note that the power command, the total POB, the discharging SOP, and the charging SOP are made to correspond to one another between condition numbers 5 to 8 and condition numbers 1 to 4. First, in the case of condition number 5, regarding the possible individual power SOP of power supply units310#1to310#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition number 1; therefore, the possible total power SOPall, which is a summation of the possible individual power SOP of power supply units310#1to310#4, is calculated to be 60 kW×4=240 kW according to Equation 1. In addition, since the power command is 160 kW and is within the possible total power SOPall, the working total power POBall can be 160 kW, which is the same as the power command. Therefore, this power command can be executed. Further, regarding the working individual power of each of power supply units310, the working total power POBall is distributed based on the power deviation. Here, since the power deviation is 5:4:4:3, when 160 kW is distributed according to this ratio, the working individual power POB1 of power supply unit310#1is 160 kW×(5/16)=50 kW, the working individual power POB2 of power supply unit310#2is 160 kW×(4/16)=40 kW, the working individual power POB3 of power supply unit310#3is 160 kW×(4/16)=40 kW, and the working individual power POB4 of power supply unit310#4is 160 kW×(3/16)=30 kW. Since any working individual power POBn is within the charging SOP and the discharging SOP, POBn≤SOPn holds, and charging and discharging can thus be appropriately performed. Next, in the case of condition number 6, regarding the possible individual power SOP of power supply units310#1to310#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition number 2 and condition number 5; therefore, the possible total power SOPall is 60 kW×4=240 kW. In addition, since the power command is 240 kW and is within the possible total power SOPall, the working total power POBall can be 240 kW, which is the same as the power command. However, when the working individual power of each of power supply units310is distributed according to the power deviation, the working individual power POB1 of power supply unit310#1is 240 kW×(5/16)=75 kW, the working individual power POB2 of power supply unit310#2is 240 kW×(4/16)=60 kW, the working individual power POB3 of power supply unit310#3is 240 kW×(4/16)=60 kW, and the working individual power POB4 of power supply unit310#4is 240 kW×(3/16)=45 kW. In this case, POBn≤SOPn holds for power supply units310#2to310#4, but for power supply unit310#1, the working individual power POB1 is 75 kW and exceeds 60 kW of the possible individual power SOP1; therefore, POBn≤SOPn does not hold, and the rating is exceeded. Further, in the case of condition number 7, regarding the possible individual power SOP of each of power supply units310#2to310#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition number 3. However, power supply unit310#1is in a fully-charged condition or a condition in which charging is prohibited because of some reason; therefore, the discharging SOP is 60 kW, but the charging SOP is 0. Therefore, charging is possible, but power supply unit310#1is separated from the power supply system at the time of charging. Therefore, power supply unit310#1is not charged. In this condition, the possible total power SOPall at the time of charging is 60 kW×3=180 kW. Here, if the power command for charging is 240 kW, the power command exceeds the possible total power SOPall; therefore, the working total power POBall is limited to 180 kW. Further, regarding the working individual power of charging each power supply unit310, since power supply unit310#1does not function because of being separated, the working individual power POB2 of power supply unit310#2is 180 kW×(4/16)=65 kW, the working individual power POB3 of power supply unit310#3is 180 kW×(4/16)=65 kW, and the working individual power POB4 of power supply unit310#4is 180 kW×(3/16)=49 kW. In this case, POBn≤SOPn holds for power supply unit310#4; however, for power supply units310#2and310#3, although each of the possible individual power SOP2 and SOP3 is 60 kW, each of the working individual power POB2 and POB3 is 65 kW. As a result, POBn≤SOPn does not hold at the time of charging, and the rating is exceeded. Further, in the case of condition number 8, regarding possible individual power SOP for each of power supply units310#2to310#4, the charging SOP and the discharging SOP are both 60 kW, but power supply unit310#1is being charged with a constant voltage or is in a condition in which the charging power is set lower than other power supply units310#2to310#4because of some reason. Therefore, the discharging SOP is 60 kW, but the charging SOP is 20 kW. In this condition, the possible total power SOPall at the time of charging is calculated to be 20 kW×4=80 kW according to Equation 1. Here, if the power command is 240 kW, the power command is greater than the possible total power SOPall, and the working total power POBall is therefore limited to 80 kW. Further, regarding the working individual power of charging each power supply unit310, the working individual power POB1 of power supply unit310#1is 80 kW×(5/16)=25 kW, the working individual power POB2 of power supply unit310#2is 80 kW×(4/16)=20 kW, the working individual power POB3 of power supply unit310#3is 80 kW×(4/16)=20 kW, and the working individual power POB4 of power supply unit310#4is 80 kW×(3/16)=15 kW. In this case, POBn≤SOPn holds for power supply units310#2to310#4; however, for power supply units310#1, although the possible individual power SOP1 is 20 kW, the working individual power POB1 is 25 kW. As a result, POBn≤SOPn does not hold at the time of charging, and the rating is exceeded. (Power Control Method According to Exemplary Embodiment) As described above, if there is a power deviation, a problem can occur, for example, the power supply system abnormality stops due to an incident in which the rating is exceeded in a part of power supply units even under the same condition. To address this issue, in the present exemplary embodiment, the working total power POBall is determined on the basis of the power deviation, and then on the basis of the working individual power POBall, charging and discharging of each power supply unit is controlled. Specifically, a chargeable and dischargeable maximum power is calculated for each power supply unit. With this arrangement, the charging SOPn and the discharging SOPn of each power supply unit are calculated. In addition, a measurement is performed at an appropriate time to detect whether there is a power deviation occurring. Specifically, a voltage and a current are continuously measured at an appropriate time to measure POBn/SOPn. Here, as described above, the SOPn is a possible individual power of power supply unit n, and the POBn is a working individual power of power supply unit n. In the above-described manner, the power supply system calculates the total SOP (possible total power SOPall) from the SOPn, the POBn, and the power deviation information measured at an appropriate time, and the power supply system communicates the calculated total SOP to power conditioner140. In the present exemplary embodiment, following Equation 2 is calculated to obtain the total SOP. TotalSOP=Σ(allpowersupplyunitsexceptpowersupplyunitwithSOP=0)(SOPm×DOBn)=SOPm×ΣDOBn=SOPm×Σ(POBn/POBm)=SOPm×Σ(POBn)/POBm=SOPm×(totalPOB)/POBmEquation2 In above Equation 2, DOBn represents a normalized power deviation ratio. DOBn represents the ratio of the electric power of each of the power supply units and is normalized such that the ratio of power supply unit #m with which the above POBn/SOPn is largest is 1. The numeral n for the power supply unit with which the POBn/SOPn is largest is substituted by m. Note that, as described above, power supply unit #n is supposed to be separated from power conditioner140at the time when the SOPn becomes 0. If power supply unit #n is not separated, the total SOP needs to be set to 0. Power conditioner140follows the power command and suppresses electric power such that the charging and discharging power is kept not greater than the total SOP. With this configuration, in a situation in which there is a power deviation occurring, even when a certain power supply unit stops or the SOPn becomes 0, an appropriate electric power suppression can be performed. Further, even when the SOPn of a certain power supply unit decreases, it is possible to keep the electric power of the certain power supply unit not greater than the SOPn. In other words, it is possible to maintain the condition of POBn≤SOPn. As a result, even in a situation in which there is a power deviation occurring, the system does not stop, and an operation of charging and discharging can be continued. Here, a description is given, with reference toFIG.5, on an example in which charging and discharging control is performed, in the conditions corresponding toFIG.4, by a power control method according to the present exemplary embodiment. With reference toFIG.5, the power command, the discharging SOP, and the charging SOP of condition numbers 1 to 8 are made to be identical to the examples represented by condition numbers 1 to 8 ofFIG.4. (Exemplary Embodiment when there is No Power Deviation) Also inFIG.5, the examples represented by condition numbers 1 to 4 show the case in which there is no power deviation occurring among power supply units10#1to10#4as is the case with condition numbers 1 to 4 ofFIG.4and in which the discharging SOP and the charging SOP of power supply units10are each 1:1:1:1. First, in the case of condition number 1, regarding the possible individual power SOP of each of power supply units10#1to10#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition number 1 ofFIG.4, and the total POB (working total power POBall) is 160 kW. Here, with respect to each of power supply units10#1to10#4, power deviation ratio dob_n is calculated. Note that power deviation ratio dob_n is not normalized as the DOBn, and satisfies Σdob_n=1. Regarding power supply unit10#1, dob_1=POB1/(total POB)=40 kW/(40+40+40+40) kW=0.25, regarding power supply unit10#2, dob_2=POB2/(total POB)=40 kW/(40+40+40+40) kW=0.25, regarding power supply unit10#3, dob_3=POB3/(total POB)=40 kW/(40+40+40+40) kW=0.25, and regarding power supply unit10#4, dob_4=POB4/(total POB)=40 kW/(40+40+40+40) kW=0.25. Therefore, power deviation ratios dob_n for power supply units10#1to10#4are the same, and power supply unit10having maximum power deviation ratio dob_n is supposed here to be power supply unit10#1(m=1). Thus, when the total SOP (possible total power SOPall) is calculated according to Equation 2, total SOP=SOPm×(total POB)/POBm=SOP1×(total POB)/POB1=60 kW×160 kW/40 kW=240 kW. Further, regarding the working individual power of each power supply unit10, the working individual power POB1 of power supply unit10#1is 160 kW×dob_1=40 kW, the working individual power POB2 of power supply unit10#2is 160 kW×dob_2=40 kW, the working individual power POB3 of power supply unit10#3is 160 kW×dob_3=40 kW, and the working individual power POB4 of power supply unit10#4is 160 kW×dob_4=40 kW. Here, since the possible individual power SOP1 to SOP4 of power supply units10are each 60 kW for both of the discharging SOP and the charging SOP as described above, the working individual power of 40 kW can be dealt with, and POBn≤SOPn thus holds. As a result, the result is the same as in the case of condition number 1 ofFIG.4. Similarly, in the case of condition number 2, the possible total power SOPall is 60 kW×4=240 kW for both of discharging and charging, and the total POB is 240 kW as is the case with condition number 1. Further, power deviation ratios dob_n for power supply units10#1to10#4are the same, and power supply unit10having maximum power deviation ratio dob_n is also supposed here to be power supply unit10#1(m=1). Thus, the total SOP (possible total power SOPall) is calculated according to Equation 2, as total SOP=SOPm×(total POB)/POBm=SOP1×(total POB)/POB1=60 kW×240 kW/60 kW=240 kW. Further, regarding the working individual power of each power supply unit10, the working individual power POB1 of power supply unit10#1is 240 kW×dob_1=60 kW, the working individual power POB2 of power supply unit10#2is 240 kW×dob_2=60 kW, the working individual power POB3 of power supply unit10#3is 240 kW×dob_3=60 kW, and the working individual power POB4 of power supply unit10#4is 240 kW×dob_4=60 kW. Here, since the possible individual power SOP1 to SOP4 of power supply units10are each 60 kW for both of the discharging SOP and the charging SOP as described above, the working individual power of 60 kW can be dealt with, and POBn≤SOPn thus holds, resulting in the same situation as in the case of condition number 2 ofFIG.4as a result. On the other hand, in the case of condition number 3, the total POB is 180 kW, and the possible individual power SOP of power supply units10#2to10#4are each 60 kW for both of the charging SOP and the discharging SOP as is the case with condition numbers 1 and 2. Further, since power supply unit10#1is fully charged, the discharging SOP is 60 kW, and the charging SOP is 0. Therefore, power supply unit10#1can be discharged but is separated from power conditioner140at the time of charging. Note that power deviation ratios dob_n for power supply units10#2to10#4are the same, and power supply unit10having maximum power deviation ratio dob_n is supposed here to be power supply unit10#2(m=2). In this condition, the possible total power SOPall at the time of charging is calculated according to Equation 2, as total SOP=SOPm×(total POB)/POBm=SOP2×(total POB)/POB2=60 kW×180 kW/60 kW=180 kW. Further, regarding the working individual power of each power supply unit10, power supply unit10#1is separated from power conditioner140and is thus not taken into account, the working individual power POB2 of power supply unit10#2is 180 kW×dob_2=60 kW, the working individual power POB3 of power supply unit10#3is 180 kW×dob_3=60 kW, and the working individual power POB4 of power supply unit10#4is 180 kW×dob_4=60 kW. Any of the working individual power POB2 to POB4can be dealt with by 60 kW of the charging SOP, and POBn≤SOPn thus holds, resulting in the same situation as in the case of condition number 3 ofFIG.4as a result. Further, in the case of condition number 4, the total POB is 80 kW, and the possible individual power SOP of each of power supply units10#2to10#4is 60 kW for both of the charging SOP and the discharging SOP as is the case with condition numbers 1 to 3; however, since power supply unit10#1is being charged by constant voltage charging, the discharging SOP is 60 kW, and the charging SOP is 20 kW. Note that, regarding power supply units10#1to10#4, since power deviation ratios dob_n at the time of charging are the same, and power supply unit10having maximum power deviation ratio dob_n is also supposed here to be power supply unit10#1(m=1). In this condition, the possible total power SOPall is calculated according to Equation 2, as total SOP=SOPm×(total POB)/POBm=SOP1×(total POB)/POB1=20 kW×80 kW/20 kW=80 kW. Further, regarding the working individual power of each power supply unit10, the working individual power POB1 of power supply unit10#1is 80 kW×dob_1=20 kW, the working individual power POB2 of power supply unit10#2is 80 kW×dob_2=20 kW, the working individual power POB3 of power supply unit10#3is 80 kW×dob_3=20 kW, and the working individual power POB4 of power supply unit10#4is 80 kW×dob_4=20 kW. Any of the working individual power can be dealt with by 20 kW and 60 kW of the charging SOP1 to SOP4, and POBn≤SOPn thus holds, resulting in the same situation as in the case of condition number 4 ofFIG.4as a result. (Exemplary Embodiment: When There is Power Deviation) As described above, by the power control method according to the exemplary embodiment, also in the condition in which there is no power deviation among power supply units10, charging and discharging power control can be appropriately performed in any of the cases of condition numbers 1 to 4. Next, a discussion is made on condition numbers 5 to 8 in the case in which the power deviation of power supply units10#1to10#4is a current ratio of 5:4:4:3 as is the case withFIG.5. Note that the power command, the total POB, the discharging SOP, and the charging SOP are made to correspond to one another between condition numbers 5 to 8 and condition numbers 1 to 4. First, in the case of condition number 5, regarding the possible individual power SOP of each of power supply units10#1to10#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition number 1, and the total POB is 160 kW. Further, power deviation ratio dob_n calculated with respect to each of power supply units10#1to10#4is as follows: regarding power supply unit10#1, dob_1=POB1/(total POB)=50 kW/160 kW=0.3125; regarding power supply unit10#2, dob_22=POB2/(total POB)=40 kW/160 kW=0.25; regarding power supply unit10#3, dob_3=POB3/(total POB)=40 kW/160 kW=0.25; and regarding power supply unit10#4, dob_4=POB4/(total POB)=30 kW/160 kW=0.1875. Therefore, power supply unit10having maximum power deviation ratio dob_n is power supply unit10#1(m=1). Thus, when the total SOP (possible total power SOPall) is calculated according to Equation 2, total SOP=SOPm×(total POB)/POBm=SOP1×(total POB)/POB1=60 kW×160 kW/50 kW=192 kW. Further, regarding the working individual power of each power supply unit10, the working individual power POB1 of power supply unit10#1is 160 kW×dob_1=50 kW, the working individual power POB2 of power supply unit10#2is 160 kW×dob_2=40 kW, the working individual power POB3 of power supply unit10#3is 160 kW×dob_3=40 kW, and the working individual power POB4 of power supply unit10#4is 160 kW×dob_4=40 kW. Here, since the possible individual power SOP1 to SOP4 of power supply units10are each 60 kW for both of the discharging SOP and the charging SOP as described above, each working individual power POBn can be dealt with, and POBn≤SOPn thus holds. Next, in the case of condition number 6, regarding the possible individual power SOP of each of power supply units10#1to10#4, the charging and the discharging SOP are both 60 kW as is the case with condition number 2, and the total POB is 192 kW. Further, power deviation ratio dob_n calculated with respect to each of power supply units10#1to10#4is as follows: regarding power supply unit10#1, dob_1=POB1/(total POB)=60 kW/192 kW=0.3125; regarding power supply unit10#2, dob_2=POB2/(total POB)=48 kW/192 kW=0.25; regarding power supply unit10#3, dob_3=POB3/(total POB)=48 kW/192 kW=0.25; and regarding power supply unit10#4, dob_4=POB4/(total POB)=36 kW/192 kW=0.1875. Therefore, power supply unit10having maximum power deviation ratio dob_n is power supply unit10#1(m=1). Thus, when the total SOP is calculated according to Equation 2, total SOP=SOPm×(total POB)/POBm=SOP1×(total POB)/POB1=60 kW×192 kW/60 kW=192 kW. Further, regarding the working individual power of each power supply unit10, the working individual power POB1 of power supply unit10#1is 192 kW×dob_1=60 kW, the working individual power POB2 of power supply unit10#2is 192 kW×dob_2=48 kW, the working individual power POB3 of power supply unit10#3is 192 kW×dob_3=48 kW, and the working individual power POB4 of power supply unit10#4is 192 kW×dob_4=36 kW. Here, since the possible individual power SOP1 to SOP4 of power supply units10are each 60 kW for both of the discharging SOP and the charging SOP as described above, each working individual power POBn can be dealt with, and POBn≤SOPn thus holds. Compared with the same condition inFIG.4, the working individual power of power supply unit10#1is lowered from 75 kW to 60 kW, and it is thus possible to prevent the possible individual power, that is, a maximum rated power from being exceeded, whereby the power supply system can stably operate. Further, in the case of condition number 7, regarding the possible individual power SOP of each of power supply units10#2to10#4, the charging SOP and the discharging SOP are both 60 kW as is the case with condition number 3; however, power supply unit10#1is fully charged, whereby the discharging SOP is 60 kW, and the charging SOP is 0. Therefore, charging is possible, but power supply unit10#1is separated from the power supply system at the time of charging. In addition, the total POB is 165 kW. Here, power deviation ratio dob_n, at the time of charging, calculated with respect to each of power supply units10#2to10#4is as follows: regarding power supply unit10#2, dob_2=POB2/(total POB)=60 kW/165 kW=0.3637; regarding power supply unit10#3, dob_3=POB3/(total POB)=60 kW/165 kW=0.3637; and regarding power supply unit10#4, dob_4=POB4/(total POB)=45 kW/165 kW=0.2728. Therefore, power supply unit10having maximum power deviation ratio dob_n is power supply units10#2and10#3. Here, when the total SOP at the time of charging is calculated according to Equation 2 assuming that power supply unit10having the maximum power deviation is power supply unit10#2(m=2), total SOP=SOPm×(total POB)/POBm=SOP2×(total POB)/POB2=60 kW×165 kW/60 kW=165 kW. Further, regarding the working individual power, at the time of charging, of each power supply unit10, the working individual power POB2 of power supply unit10#2is 165 kW×dob_2=60 kW, the working individual power POB3 of power supply unit10#3is 165 kW×dob_3=60 kW, and the working individual power POB4 of power supply unit10#4is 165 kW×dob_4=45 kW. Here, since the possible individual power SOP2 to SOP4 of each of power supply units10is 60 kW for both of the discharging SOP and the charging SOP as described above, each working individual power POBn can be dealt with, and POBn≤SOPn thus holds. Compared with the same condition inFIG.4, the working individual power of each of power supply units10#2and10#3is lowered from 65 kW to 60 kW, and it is thus possible to prevent the maximum rated power from being exceeded, whereby the power supply system can stably operate. Further, in the case of condition number 8, as is the case with condition number 4, the possible individual power SOP of each of power supply units10#2to10#4is 60 kW for both of the charging SOP and the discharging SOP, power supply unit10#1is being charged by constant voltage charging, the discharging SOP is 60 kW, and the charging SOP is 20 kW. In addition, the total POB is 64 kW. Here, power deviation ratio dob_n, at the time of charging, calculated with respect to each of power supply units10#1to10#4is as follows: regarding power supply unit10#1, dob_1=POB1/(total POB)=20 kW/64 kW=0.3125; regarding power supply unit10#2, dob_2=POB2/(total POB)=16 kW/64 kW=0.25; regarding power supply unit10#3, dob_3=POB3/(total POB)=16 kW/64 kW=0.25; and regarding power supply unit10#4, dob_4=POB4/(total POB)=12 kW/64 kW=0.1875. Therefore, power supply unit10having maximum power deviation ratio dob_n is power supply unit10#1. Thus, when the total SOP at the time of charging is calculated by Equation 2 where m=1, the calculation result is total SOP=SOPm×(total POB)/POBm=SOP1×(total POB)/POB1=20 kW×64 kW/20 kW=64 kW. Further, regarding the working individual power, at the time of charging, of each power supply unit10, the working individual power POB1 of power supply unit10#1is 64 kW×dob_1=20 kW, the working individual power POB2 of power supply unit10#2is 64 kW×dob_2=16 kW, the working individual power POB3 of power supply unit10#3is 64 kW×dob_3=16 kW, and the working individual power POB4 of power supply unit10#4is 64 kW×dob_4=12 kW. Thus, the possible individual power SOP1 to SOP4 of power supply units10can respectively deal with working individual power POB1 to POB4, and POBn≤SOPn thus holds. Compared with the same condition inFIG.4, the working individual power of power supply unit10#1is lowered from 25 kW to 20 kW, and it is thus possible to prevent the maximum rated power from being exceeded, whereby the power supply system can stably operate. By using the above method, it is possible to perform charging and discharging control depending on the power deviation, and an unintended system failure can thus be avoided. Note that the power deviation can be detected at a constant cycle, and the working individual power can be updated on the basis of the detected power deviation. This arrangement enables appropriate adjustment of the charging and discharging power, coping with the battery condition temporally varying from hour to hour. The power deviation is preferably detected on the controller on the unit side and sent out to master controller120. However, the present invention does not limit the timing of detection of the power deviation to a cyclic detection, and the detection can be performed at an arbitrary timing. For example, the detection timing may be varied, for example, the detection may be performed at the time when an issue implying change in the power deviation occurs, or the detection may be performed at long intervals when the power deviation does not often change or at short intervals when the power deviation often changes. Further, the method for measuring the power deviation and the like is not limited to the measurement of a voltage or a current, and other methods can be used appropriately. Further, in the example ofFIG.1, master controller120calculates the power deviation and communicates the power deviation to power conditioner140; however, other than this configuration, the power deviation may be calculated by the system controller or the power conditioner. Alternatively, the function of calculating the power deviation may be provided on the unit controller side. For example, in a power supply system according to a modified example shownFIG.6, unit controller12′ of power supply unit10#1includes the function of calculating the power deviation and plays a role of the master controller. In this case, the master controller does not need to be provided. INDUSTRIAL APPLICABILITY A power supply system and a power conditioner according to the present invention can be suitably used as a large-scale power storage device used in a power plant or the like and as a controller of the power storage device. REFERENCE MARKS IN THE DRAWINGS 1000power supply system1battery module10,10#1to10#4,210,310,310#1to310#4power supply unit11,211,311battery aggregation12,12′,212,312unit controller (BMU)14,214,314switch100control system120master controller (M-BMU)140,240,340power conditioner160system controllerES power system | 42,997 |
11862979 | DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Microgrids and smart grids are gradually evolving from conventional power systems. In microgrids, interconnected sub-grids govern power distribution with high penetration of renewable energy resources and energy storage systems. In a hybrid AC/DC microgrid (HMG) system, operational functionalities of both AC (alternating current) and DC (direct current) currents are made available in order to avoid frequent conversions (i.e., from AC to DC and from DC to AC) so as to minimize energy losses and also to feed DC loads directly. Microgrids typically comprise a combination of distributed energy resources or assets (DER), such as, but not limited to, a combined heat-and-power system, solar panels, wind-generators or turbines, fuels cells, and energy storage (e.g., a battery energy storage system, or BESS). In a microgrid, a battery energy storage system (BESS) is used mainly for peak shaving (i.e., the process of reducing the amount of energy purchased or obtained from a utility company during peak demand hours by using an alternative localized power source), and for minimization of frequency and power fluctuations resulting from solar irradiance variation or wind speed change (for solar or wind-based energy sources). DER are managed by a microgrid controller and a network of auxiliary control devices to help achieve grid resiliency, which generally encompasses reducing and coping with power outages efficiently, lessening the impact of an outage, and regrouping from an outage quickly. In the event of a utility grid outage, the microgrid will safely disconnect to “island” from the grid, support critical loads in the microgrid, and then reconnect when the outage event has been corrected (i.e., grid-connected mode). Improving resiliency and transient stability during large signal disturbances in an “islanded” HMG comprising different DER is a challenging task. Typically, in prior art system, auxiliary control devices such as a series dynamic braking resistor (SDBR), fault current limiters, and the like, are used to improve the transient stability of the HMG system, which incur higher additional costs. In several embodiments, the present invention comprises an improved “3-in-1” BESS that performs three functions: (1) improving the transient stability in the HMG during any fault; (2) improving power quality in the HMG during any sudden load change; and (3) mitigating power and frequency fluctuations due to variations in wind speed and/or solar irradiance in the HMG. The same control and structural design is used for all three functions, and the improved BESS thus is adaptive to the changing operating situations within the HMG, and eliminates the requirement for a number of higher cost auxiliary control devices. The control structure of the improved BESS is simple, so it is easier and cheaper to manufacture, and can be easily implemented in practice, and retro-fit into existing HMGs. An example of a BESS control system100in accordance with the present invention is shown inFIG.1. A BESS power circuit200with control signals is shown inFIG.2. The system includes functionalities of both a droop based control method (a speed control mode used for AC electrical power generators whereby the power output of a generator reduces as the line frequency increases) and a grid-feeding strategy for an inverter interfaced energy storage system. In grid-feeding strategy, the BESS inverter is controlled to inject/absorb active/reactive powers. In this method, by good approximation it is assumed that the inverter output active and reactive power correspond independently to inverter frequency and voltage magnitude, respectively. Therefore, the BESS control system tracks the power references (P*, Q*) applied by the power management system. These references can be constant values defined by the system operator depending on the grid condition or power mismatches between load and generating resources. The droop-based control110is obtained using P-ω and Q-V droops, where ω and V are AC sub-grid voltage and frequency, respectively. The power references are defined as below: Pref=P*-mp(ω-ω*)Qref=Q*-nq(V-V*)(1)mp≥Pmax-Pminω*np≥Vmax-VminV*(2) where * denotes rated set points, and mpand nqare droop gains for power sharing. In order to enable the BESS to contribute in power fluctuation minimization during intermittent renewable generation, the active power reference is made equal to power balance mismatch: P*=PLac−[PDFJG+PDG+PIC] (3) where PLac, PDFJG, PDG, and PDGrepresent the Total Load, DFIG, DG and IC output powers (P), respectively. In this way, the BESS absorbs/injects the amount of power mismatched between load and generation. The reactive power reference Q* depends on the grid voltage control and inverter maximum current limit. The BESS is usually used as an active power device to control the flow of energy. Therefore, Q* is made to be zero. Although the BESS inverter can appropriately be used as a static compensator, the reactive power absorption/injection will limit the active power capability of the inverter. PESand QES120are filtered output powers inFIG.1, and p and q are respectively calculated unfiltered positive sequence output powers from measured signals. PES=ωcs+ωcpQES=ωcs+ωcq(4)p=32[vacdiεSd+vacqiESq]q=32[vacqiESd-vacdiESq](5) The present invention applies a dual loop decoupled control structure with the droop-based concept to recondition active and reactive reference powers. In this strategy, while the system tracks the applied power references, the droop block adaptively regulates references according to current operating conditions of microgrid voltage and frequency. In order to have an independent regulation over active and reactive powers, the control system is implemented in a Stationary Reference Frame (SRF) dq system, where d axis corresponds to active power control and q axis corresponds to reactive power control. In this way two axes are decoupled through the feedforward terms of ωLfwhich is the output inductor's derivative voltage effect appearing when transforming from Natural Reference Frame (NRF) abc system to dq frame. Proportional-Integral (PI) controllers are utilized to regulate power and current components. In order to design PI regulators coefficients (Kp, Ki), in several embodiments the system is linearized around an operating point that ensures the system stability for different operating conditions. It is noteworthy that the designed coefficient set remains unchanged during any type of disturbances. A question may arise about how one set of coefficients works for all three situations. PI parameters are tuned to have the best response in order to track the active and reactive power references in all situations. In these situations, power balances are affected by disturbances. So, the PIs are first designed for the worst case (that is the fault disturbance) and then fine-tuned to adapt to other disruptions. FIG.3shows an exemplary HMG system300in accordance with the present invention. The Medium Voltage (MV) AC sub-grid contains a Doubly Fed Induction Generator (DFIG) based variable speed wind generator310and a Diesel Generator (DG)320, both connected at the point of common coupling (PCC). The wind-diesel generation system in AC sub-grid is collocated with a BESS330to provide peak shaving service during wind speed fluctuations and to enhance resiliency against large signal disturbances. The DC sub-grid comprises Photovoltaic (PV) solar panels340, a peak shaving BESS350for mitigating solar irradiance fluctuations, and constant DC loads360.FIG.4shows the various parameters of the HMG system, including the AC BESS and the DC BESS, used in this exemplary embodiment. The HMG system ofFIG.3, as well as the complete control system, have been simulated in a MATLAB\Simulink environment with detailed switching models for all power electronic devices. The sample time for discrete time simulations is chosen as 5 μs. Therefore, with detailed modeling and very short sample time it is ensured that system dynamics and performance evaluation are reflected with highest accuracy. FIGS.5-10show the responses of various variables of the HMG system with and without the proposed BESS under three major disturbances as described below.FIG.5shows AC sub-grid frequency (F),FIG.6shows AC subgrid voltage RMS value (phase A),FIG.7shows DFIG output power,FIG.8shows DFIG shaft rotational speed,FIG.9shows load active power, andFIG.10shows BESS active power for the system ofFIG.3. From the responses, it has been shown that the proposed BESS can not only perform its typical function of minimization of frequency and power fluctuations during wind speed/solar irradiance change, but also can well maintain the transient stability and enhance the resiliency of the HMG system under fault condition as well as the load change situation. In other words, the BESS can effectively perform three functions in the HMG environment. Disturbance 1—Wind speed variation: Intermittent wind velocity is simulated by two step changes. The nominal velocity is 14 m/s. A disturbance is simulated by wind velocity change to 60% and 140%, each for 2.0 sec duration, at the time of 10.0 sec and 12.0 sec, respectively. Disturbance 2—Fault at AC sub-grid: A 100% three-line-to-ground (3LG) short circuit, which is considered as the severest fault in a power network, is applied at the location F inFIG.3at tf=28.0 sec for a duration of 133 ms (i.e., 8 cycles). Disturbance 3—Dynamic load step change: A step change in dynamic load happens in AC subgrid for a duration of 2.0 sec. This load is a 205 KW variable induction motor that emulates a highly nonlinear and dynamic performance. The nominal mechanical torque of motor is 1100 N-m. A disturbance is simulated by a step change in mechanical torque to 20% and a step change to 120% of nominal torque, each for 1.0 sec duration, at the time of 38 sec and 39 sec, respectively. The present invention comprises significant advantages over the prior art in that the BESS can be utilized for resiliency enhancement during large signal disturbances in an HMG system. In other words, the BESS can maintain the transient stability during any fault conditions as well as any load change situations, in addition to its typical function of minimization of frequency and power fluctuations during wind speed/solar irradiance change. The BESS thus is used to improve the resiliency of the HMG, resulting in a savings from foregoing the cost of putting auxiliary devices in during fault conditions and load change situations. Some aspects of a system in accordance with the present invention may be controlled through computer-implemented systems, hardware, and programs. In order to provide a context for the various computer-implemented aspects of the invention, the following discussion provides a brief, general description of a suitable computing environment in which the various aspects of the present invention may be implemented. A computing system environment is one example of a suitable computing environment, but is not intended to suggest any limitation as to the scope of use or functionality of the invention. A computing environment may contain any one or combination of components discussed below, and may contain additional components, or some of the illustrated components may be absent. Various embodiments of the invention are operational with numerous general purpose or special purpose computing systems, environments or configurations. Examples of computing systems, environments, or configurations that may be suitable for use with various embodiments of the invention include, but are not limited to, personal computers, laptop computers, computer servers, computer notebooks, hand-held devices, microprocessor-based systems, multiprocessor systems, TV set-top boxes and devices, programmable consumer electronics, cell phones, personal digital assistants (PDAs), tablets, smart phones, touch screen devices, smart TV, internet enabled appliances, internet enabled security systems, internet enabled gaming systems, internet enabled watches; internet enabled cars (or transportation), network PCs, minicomputers, mainframe computers, embedded systems, virtual systems, distributed computing environments, streaming environments, volatile environments, and the like. Embodiments of the invention may be implemented in the form of computer-executable instructions, such as program code or program modules, being executed by a computer, virtual computer, or computing device. Program code or modules may include programs, objects, components, data elements and structures, routines, subroutines, functions and the like. These are used to perform or implement particular tasks or functions. Embodiments of the invention also may be implemented in distributed computing environments. In such environments, tasks are performed by remote processing devices linked via a communications network or other data transmission medium, and data and program code or modules may be located in both local and remote computer storage media including memory storage devices such as, but not limited to, hard drives, solid state drives (SSD), flash drives, USB drives, optical drives, and internet-based storage (e.g., “cloud” storage). In one embodiment, a computer system comprises multiple client devices in communication with one or more server devices through or over a network, although in some cases no server device is used. In various embodiments, the network may comprise the Internet, an intranet, Wide Area Network (WAN), or Local Area Network (LAN). It should be noted that many of the methods of the present invention are operable within a single computing device. A client device may be any type of processor-based platform that is connected to a network and that interacts with one or more application programs. The client devices each comprise a computer-readable medium in the form of volatile and/or nonvolatile memory such as read only memory (ROM) and random access memory (RAM) in communication with a processor. The processor executes computer-executable program instructions stored in memory. Examples of such processors include, but are not limited to, microprocessors, ASICs, and the like. Client devices may further comprise computer-readable media in communication with the processor, said media storing program code, modules and instructions that, when executed by the processor, cause the processor to execute the program and perform the steps described herein. Computer readable media can be any available media that can be accessed by computer or computing device and includes both volatile and nonvolatile media, and removable and non-removable media. Computer-readable media may further comprise computer storage media and communication media. Computer storage media comprises media for storage of information, such as computer readable instructions, data, data structures, or program code or modules. Examples of computer-readable media include, but are not limited to, any electronic, optical, magnetic, or other storage or transmission device, a floppy disk, hard disk drive, CD-ROM, DVD, magnetic disk, memory chip, ROM, RAM, EEPROM, flash memory or other memory technology, an ASIC, a configured processor, CDROM, DVD or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium from which a computer processor can read instructions or that can store desired information. Communication media comprises media that may transmit or carry instructions to a computer, including, but not limited to, a router, private or public network, wired network, direct wired connection, wireless network, other wireless media (such as acoustic, RF, infrared, or the like) or other transmission device or channel. This may include computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism. Said transmission may be wired, wireless, or both. Combinations of any of the above should also be included within the scope of computer readable media. The instructions may comprise code from any computer-programming language, including, for example, C, C++, C#, Visual Basic, Java, and the like. Components of a general purpose client or computing device may further include a system bus that connects various system components, including the memory and processor. A system bus may be any of several types of bus structures, including, but not limited to, a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. Such architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus. Computing and client devices also may include a basic input/output system (BIOS), which contains the basic routines that help to transfer information between elements within a computer, such as during start-up. BIOS typically is stored in ROM. In contrast, RAM typically contains data or program code or modules that are accessible to or presently being operated on by processor, such as, but not limited to, the operating system, application program, and data. Client devices also may comprise a variety of other internal or external components, such as a monitor or display, a keyboard, a mouse, a trackball, a pointing device, touch pad, microphone, joystick, satellite dish, scanner, a disk drive, a CD-ROM or DVD drive, or other input or output devices. These and other devices are typically connected to the processor through a user input interface coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, serial port, game port or a universal serial bus (USB). A monitor or other type of display device is typically connected to the system bus via a video interface. In addition to the monitor, client devices may also include other peripheral output devices such as speakers and printer, which may be connected through an output peripheral interface. Client devices may operate on any operating system capable of supporting an application of the type disclosed herein. Client devices also may support a browser or browser-enabled application. Examples of client devices include, but are not limited to, personal computers, laptop computers, personal digital assistants, computer notebooks, hand-held devices, cellular phones, mobile phones, smart phones, pagers, digital tablets, Internet appliances, and other processor-based devices. Users may communicate with each other, and with other systems, networks, and devices, over the network through the respective client devices. Thus, it should be understood that the embodiments and examples described herein have been chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited for particular uses contemplated. Even though specific embodiments of this invention have been described, they are not to be taken as exhaustive. There are several variations that will be apparent to those skilled in the art. | 19,589 |
11862980 | DETAILED DESCRIPTION Embodiments of the present disclosure solve the technical problem of underutilized interconnection infrastructure. Legacy renewable power plants, (LRPPs) often have peak outputs that are much higher than their average output. Interconnection infrastructure, such as a gen-tie, connects an LRPP to a grid, such as a utility grid. The interconnection infrastructure must have a transmission capacity high enough to handle a peak output of the LRPP. The transmission capacity is, however, much higher than an average output of the LRPP. Stated otherwise, the LRPP has a low capacity factor. The transmission capacity is thus under-used most of the time. By adding an add-on renewable power plant (ARPP) to the interconnection infrastructure, the transmission capacity of the interconnection infrastructure can be more fully used more of the time. Adding an ARPP to the interconnection infrastructure also solves the technical problem of reducing interconnection infrastructure requirements for a new power plant. A new interconnection infrastructure requires significant amounts of materials and may involve digging trenches or burying transmission lines for significant distances, often through land owned by third parties. Adding an ARPP to the interconnection infrastructure avoids these issues. FIG.1is an example legacy renewable power plant (LRPP)100, in accordance with one or more embodiments. The LRPP may include a legacy energy management system (LEMS)110. The LEMS110may be a controller. The LEMS110may send and receive signals from an inverter124and a power meter130. The LRPP may include a renewable energy source (RES)122. The RES122may be a solar array. The inverter124may convert DC power from the RES122to AC power. The inverter124may regulate an output of the RES122to control an LRPP output. The LEMS110may control the LRPP inverter124to control the LRPP output. The LEMS110may transmit setpoints to the LRPP inverter124. The setpoints may be voltage setpoints, current setpoints, or real and/or reactive power setpoints. A setpoint is a command to an inverter to generate an output specified in the setpoint. The LRPP power meter130may provide feedback to the LEMS110for controlling the LRPP output. The LRPP may include a transformer140, and an interconnection infrastructure150. The interconnection infrastructure may include a switchyard and local substation, a gen-tie, and a point-of-interconnect (POI) substation. The POI substation may connect to a grid, such as a utility grid. The transformer140may step up a voltage of the LRPP output for transmitting power through the interconnection infrastructure to the grid. The LRPP may have a power output profile which shows how the LRPP output changes over an interval. The LRPP power output profile may be an average of the LRPP output for a plurality of intervals, a representative interval from the plurality of intervals, or a weighted average of the plurality of intervals. For example, the LRPP power output profile may show how the LRPP output changes over the course of a day. If the RES122is a solar array, the LRPP power output profile may show the LRPP output rise in the morning as the LRPP is exposed to more sunlight, peak at noon, and drop off through the afternoon and evening as the sun sets. In some embodiments, a peak LRPP output may be limited by a transmission capacity of the interconnection infrastructure150. In other embodiments, the transmission capacity of the interconnection infrastructure150may be based on the peak LRPP output. In some embodiments, the transmission capacity is no more than 150% of the peak LRPP output. The peak LRPP output is higher than an average LRPP output. The transmission capacity of the interconnection infrastructure150may be underutilized. For example, if the RES122is a solar array, the peak LRPP output at noon may be much higher than the LRPP output in the morning and in the evening, meaning the transmission capacity of the interconnection infrastructure150is only fully used at noon and only partially used in the morning and the evening. FIG.2is an example add-on renewable power plant (ARPP) connected to an LRPP interconnection infrastructure250upstream of an LRPP transformer240, in accordance with one or more embodiments. The LRPP may be the LRPP ofFIG.1. The LRPP may include a legacy energy management system (LEMS)210. The LEMS210may be or include a controller. The LEMS210may send and receive signals from an LRPP inverter224and an LRPP power meter230. The LRPP may include an LRPP renewable energy source (RES)222. The LRPP RES222may be a solar array. The LRPP may include a transformer240, an interconnection infrastructure power meter245, and an LRPP interconnection infrastructure250. In some embodiments, the interconnection infrastructure power meter245may be in a gen-tie of the interconnection infrastructure. The interconnection infrastructure power meter245may be added to the LRPP interconnection infrastructure250when the ARPP is connected to the LRPP interconnection infrastructure250. The LRPP interconnection infrastructure250may include a switchyard and local substation, the gen-tie, and a POI substation. The LEMS210may control the LRPP inverter224to regulate an LRPP output. The LEMS210may transmit LRPP inverter setpoints to the LRPP inverter224. The LRPP inverter setpoints may be voltage setpoints, current setpoints, or power setpoints. The LRPP power meter230may provide feedback to the LEMS210for controlling the LRPP output. The LRPP inverter224may convert DC power from the LRPP RES222to AC power. The ARPP may include an add-on energy management system (AEMS)211. The AEMS211may be a controller. The AEMS may send and receive signals from an RES inverter225, an ARPP power meter231, and an energy storage system (ESS) inverter227. The AEMS211may send and receive signals from the LEMS210. The signals from the LEMS210may include LRPP inverter setpoints for the LRPP inverter224and the LRPP power output, or an indication of the LRPP power output, as measured by the LRPP power meter230. The AEMS211may transmit RES inverter setpoints to the RES inverter225. The RES inverter setpoints may be voltage setpoints, current setpoints, or power setpoints. The AEMS may transmit ESS inverter setpoints to the ESS inverter227. The ESS inverter setpoints may be voltage setpoints, current setpoints, or power setpoints. The ESS inverter227may be a bidirectional inverter. The ARPP may include an energy storage system (ESS)229. The ARPP may include an ARPP RES223. The ARPP RES223may be a solar array, wind farm, or any other type of RES. The ESS229may be a battery energy storage system or any other type of energy storage system. The ESS229may be charged using power received from the ARPP RES223. The ESS229may discharge to provide power to the transformer240through the ARPP power meter231. The ESS inverter227may be configured to regulate a charge/discharge of the ESS229. The ESS inverter227may convert AC power from the RES inverter225to DC power to charge the ESS229. The ESS inverter227may convert DC power from the ESS229to AC power to be sent to the transformer240. The AEMS211may control the RES inverter225and the ESS inverter227to regulate how much power is generated by the ARPP RES223and how much power is charged to the ESS229or discharged from the ESS229in order to control an ARPP output. The AEMS211may control the RES inverter225and the ESS227by adjusting setpoints of the RES inverter225and the ESS227. The ARPP power meter231may measure the ARPP output and provide feedback to the AEMS211for controlling the ARPP output. The feedback to the AEMS211may be used to control the ARPP output in a closed-loop control system such that the measured output power of the ARPP is equal to the lesser of a power level based on a power sale agreement or on profitability based on current and expected market pricing for energy, or the difference between the transmission capacity and the LRPP output. The combined LRPP output and ARPP output may be received by the transformer240. The transformer240may step up the combined output for transmission through the LRPP interconnection infrastructure250. The interconnection infrastructure power meter245may measure an amount of power transmitted through the LRPP interconnection infrastructure250. The LRPP may have a power output profile which shows how the LRPP output changes over a time period. For example, the LRPP power output profile may show how the LRPP output changes over the course of a day. If the LRPP RES222is a solar array, the LRPP power output profile may show the LRPP output rise in the morning as the LRPP is exposed to more sunlight, peak at noon, and drop off through the afternoon and evening as the sun sets. In some embodiments, a peak LRPP output may be limited by a transmission capacity of the LRPP interconnection infrastructure250. In other embodiments, the transmission capacity of the LRPP interconnection infrastructure250may be based on the peak LRPP output. In some embodiments, the transmission capacity is no more than 150% of the peak LRPP output. The peak LRPP output is higher than an average LRPP output. The transmission capacity of the LRPP interconnection infrastructure250may be underutilized. For example, if the RES122is a solar array, the peak LRPP output at noon may be much higher than the LRPP output in the morning and in the evening, meaning the transmission capacity of the LRPP interconnection infrastructure250is only fully used at noon and only partially used in the morning and the evening. In some embodiments, an output capacity of the ARPP RES223may be sized based on an LRPP transmission capacity of the LRPP interconnection infrastructure. In some embodiments, the ARPP RES output capacity may be sized to be equal to the LRPP interconnection infrastructure transmission capacity. In other embodiments, the ARPP RES output capacity may be sized such that the ARPP RES223may output sufficient power to fully utilize the LRPP transmission capacity. In yet other embodiments, the ARPP RES output capacity may be sized such that the ARPP RES223may output sufficient power, when combined with the LRPP RES output and the ESS output, to fully utilize the LRPP transmission capacity. The ARPP RES output capacity may be sized such that the ARPP RES223may output sufficient power, when combined with the LRPP RES output and the ESS output, to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. A storage capacity of the ESS229may be based on the interconnection infrastructure transmission capacity and the LRPP power output profile. For example, the ARPP RES output capacity may be sized and the ESS storage capacity may be sized such that the ARPP RES223outputs sufficient power and the ESS229stores and/or outputs sufficient power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. In another example, The ARPP RES output capacity may be sized and the ESS storage capacity may be sized such that the ARPP RES223outputs sufficient power to complement the LRPP power output profile and charge the ESS229so the ESS229can output sufficient power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. The ESS storage capacity is sized to be able to store the ARPP RES output and provide stored power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. In this example, the ARPP RES223may output sufficient power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity and charge the ESS with sufficient power such that when the ARPP RES223does not output sufficient power to complement the LRPP power output profile, the ESS229may output sufficient power to complement the LRPP power output. In this example, the ARPP RES223may be a solar array which produces power during daylight hours and charges the ESS229. Before and after daylight hours when the ARPP RES223is not producing power, the ESS229may provide stored power to complement the LRPP power output profile. In some embodiments, the ARPP RES223and ESS229are sized together based on the LRPP transmission capacity and the LRPP power output profile. The ARPP RES223and ESS229may be sized such that an ARPP-LRPP combined power output is substantially equal to the LRPP transmission capacity for a target interval. The target interval may be based on the LRPP power output profile. For example, the LRPP power output profile may show the LRPP power output for a day. The target interval may be a portion of the day or the entire day, in which case the ARPP-LRPP combined power output will always be substantially equal to the LRPP transmission capacity. The ARPP RES223may be sized to produce an amount of power equal to the LRPP transmission capacity for the target interval minus an amount of power produced by the LRPP RES222as shown in the LRPP power output profile. The ESS229may be sized to store power generated by the ARPP RES223and output the stored power such that the ARPP-LRPP combined output is substantially equal to the LRPP transmission capacity. In some embodiments, the AEMS221is configured to control the ARPP output such that a variability of the ARPP-LRPP combined output has a lower variability than a variability of the LRPP output. Variability of an output is a measure of how much individual values of the output differ from a moving average of the output or from an expected pattern. In the case of variability of the LRPP output, the pattern may be the LRPP power output profile based on historic LRPP outputs. The pattern may be a pattern of how the LRPP output changes through a day. The AEMS211may control the ARPP RES output and the ESS charge/discharge to control the ARPP output. The AEMS211may track the ARPP power output using the ARPP power meter231and track the LRPP power output using the LRPP power meter230. In some embodiments, the ARPP power meter231and the LRPP power meter230continuously transmit an instantaneous ARPP output and instantaneous LRPP output to the AEMS211. In other embodiments, the AEMS211polls the ARPP power meter231and the LRPP power meter230at periodic intervals for the instantaneous ARPP output and the instantaneous LRPP output. In yet other embodiments, the AEMS211polls the ARPP power meter231and the LRPP power meter230at periodic intervals for a moving average of the ARPP output and a moving average of the LRPP output. The variability of the LRPP output may be determined in real-time and/or based on the LRPP power output profile. In some embodiments, the variability of the LRPP output may be determined by comparing measured LRPP output values to the LRPP power output profile based on historic LRPP outputs. In other embodiments, the variability of the LRPP output may be determined by comparing measured LRPP output values to a moving average of measured LRPP output values. In yet other embodiments, the variability of the LRPP output may be determined by comparing measured LRPP output values to a set of ideal LRPP output values. The set of ideal LRPP output values may be determined based on a representative or ideal irradiance values and the conversion efficiency of the LRPP. The set of ideal LRPP output values may be equal to the LRPP power output profile. The AEMS211may regulate the ARPP output and/or the ESS charge/discharge based on the variability of the LRPP output such that the ARPP-LRPP combined output has a lower variability than a variability of the LRPP output. By lowering the variability of the ARPP-LRPP combined output, the ARPP functions as a firming plant for the LRPP. In some embodiments, the AEMS211is configured to control the ARPP output such that the ARPP-LRPP combined output does not exceed the LRPP transmission capacity. The LRPP output and/or the ARPP-LRPP output may be determined in real time. The AEMS211may regulate the ARPP output and/or the ESS charge/discharge based on the LRPP output such that the ARPP-LRPP combined output does not exceed the LRPP transmission capacity. The AEMS211may track the ARPP power output using the ARPP power meter231and track the LRPP power output using the LRPP power meter230. The AEMS211may track the ARPP-LRPP combined power output using the interconnection infrastructure power meter245. The AEMS211may control the ARPP such that an instantaneous sum of the ARPP output, as measured at the ARPP power meter331, and the LRPP output, as measured at the LRPP power meter330, does not exceed a maximum permitted power flow at the point-of-interconnect (POI) to the grid. The AEMS211may control the ARPP output according to a power sale agreement and/or based on current and expected market pricing for power while ensuring that the ARPP-LRPP combined output does not exceed the LRPP transmission capacity. In some embodiments, the AEMS211may control the ARPP such that a rate of change of the ARPP-LRPP combined power output does not exceed an allowed rate of change at the POI. The AEMS211may calculate a rate of change of the ARPP-LRPP output as change in the ARPP-LRPP output over time. The AEMS211may compare the rate of change of the ARPP-LRPP output and compare it to a maximum ramp-down rate (e.g., a stored maximum ramp-down rate) and a maximum ramp-up rate (e.g., a stored maximum ramp-up rate) of the POI. The AEMS211may control the ARPP output such that a ramp-down rate of the ARPP-LRPP combined power output does not exceed the maximum ramp-down rate and that a ramp-up rate of the ARPP-LRPP combined power output does not exceed the maximum ramp-up rate. Avoiding exceeding the maximum ramp-down and ramp-up rates of the POI avoids causing harm to the grid and violating agreements with the utility organization operating the grid. In some embodiments, the AEMS211and the LEMS210may transmit inverter setpoints of the ARPP and the LRPP to a shared energy management system. The shared energy management system may resolve conflicts arising from independently set inverter setpoints of the ARPP and the LRPP. If the sum of the ARPP output and the LRPP output exceeds the LRPP interconnection infrastructure transmission capacity, the shared energy management system may send a signal to the AEMS211to reduce the ARPP output. The inverter setpoints of the ARPP and the LRPP may be sent to the shared energy management system for approval by the AEMS211and the LEMS210before being applied to inverters of the ARPP and the LRPP. The shared energy management system may compare the ARPP output and the LRPP output such that the ARPP output complements the LRPP output. The shared energy management system may receive inverter setpoints of the ARPP and the LRPP, calculate a combined output based on the received inverter setpoints, compare the combined output to a target output, and adjust the inverter setpoints of the ARPP so the combined output is equal to the target output. The shared energy management system may determine inverter setpoints for inverters of the ARPP and the LRPP based on the transmission capacity, an instantaneous LRPP output, and an instantaneous ARPP output. The shared energy management system may set the ARPP output to be equal to the transmission capacity minus the LRPP output. The shared energy management system controls the ARPP output such that the ARPP output does not exceed the transmission capacity minus the LRPP output. FIG.3is an example add-on renewable power plant (ARPP) connected to an interconnection infrastructure of an LRPP downstream of an LRPP transformer340, in accordance with one or more embodiments. The LRPP may include a legacy energy management system (LEMS)310. The LEMS310may be a controller. The LEMS310may send and receive signals from an LRPP inverter324and an LRPP power meter330. The LRPP may include an LRPP renewable energy source (RES)322. The LRPP RES322may be a solar array. The LRPP may include an LRPP RES inverter324. The LEMS310may adjust setpoints of the LRPP RES inverter324to control an LRPP RES output. A setpoint is a command to an inverter to generate an output specified in the setpoint. The LRPP may include an LRPP transformer340, an interconnection infrastructure power meter345, and an LRPP interconnection infrastructure350. In some embodiments, the interconnection infrastructure power meter345may be in a gen-tie of the interconnection infrastructure. The interconnection infrastructure power meter345may be added to the LRPP interconnection infrastructure350when the ARPP is connected to the LRPP interconnection infrastructure350. The LRPP interconnection infrastructure350may include a switchyard and local substation, the gen-tie, and a POI substation. The ARPP may include an add-on energy management system (AEMS)311. The AEMS311may be a controller. The AEMS may send and receive signals from an RES inverter325, an ARPP power meter331, and an energy storage system (ESS) inverter327. The AEMS311may send and receive signals from the LEMS310. The signals from the LEMS310may include LRPP inverter setpoints for the LRPP inverter324and the LRPP power output, or an indication of the LRPP power output, as measured by the LRPP power meter330. The AEMS311may transmit RES inverter setpoints to the ARPP RES inverter325. The RES inverter setpoints may be voltage setpoints, current setpoints, or power setpoints. The AEMS may transmit ESS inverter setpoints to the ESS inverter327. The ESS inverter setpoints may be voltage setpoints, current setpoints, or power setpoints. The ESS inverter327may be a bidirectional inverter. The ARPP may include an energy storage system (ESS)329. The ARPP may include an ARPP RES323. The ARPP RES323may be a solar array, wind farm, or any other type of RES. The ESS229may be a battery energy storage system or any other type of energy storage system. The LEMS310may control the LRPP inverter324to regulate an LRPP output. The LEMS310may transmit LRPP inverter setpoints to the LRPP inverter324. The LRPP inverter setpoints may be voltage setpoints, current setpoints, or power setpoints. The LRPP power meter330may provide feedback to the LEMS310for controlling the LRPP output. The LRPP inverter324may convert DC power from the LRPP RES322to AC power. The LRPP transformer340may step up the LRPP output for transmission through the LRPP interconnection infrastructure350. The interconnection infrastructure power meter345may measure an amount of power transmitted through the LRPP interconnection infrastructure350. The ESS329may be charged using power received from the ARPP RES323. The ESS329may discharge to provide power to the ARPP transformer341through the ARPP power meter331. The ESS inverter327may be configured to regulate a charge/discharge of the ESS329. The ESS inverter327may convert AC power from the ARPP RES inverter325to DC power to charge the ESS329. The ESS inverter327may convert DC power from the ESS329to AC power to be sent to the ARPP transformer341. The AEMS311may control the ARPP RES inverter325and the ESS inverter327to regulate how much power is generated by the ARPP RES323and how much power is charged to the ESS329or discharged from the ESS329in order to control an ARPP output. The ARPP power meter331may measure the ARPP output and provide feedback to the AEMS311for controlling the ARPP output. The ARPP transformer341may step up the ARPP output for transmission through the LRPP interconnection infrastructure350. The interconnection infrastructure power meter345may measure an amount of power transmitted through the LRPP interconnection infrastructure350. The feedback to the AEMS311may be used to control the ARPP output in a closed-loop control system such that the measured output power of the ARPP remains equal to the lesser of a power level based on a power sale agreement or on profitability based on current and expected market pricing for energy, or the difference between the transmission capacity and the LRPP output. The LRPP may have a power output profile which shows how the LRPP output changes over a time period. For example, the LRPP power output profile may show how the LRPP output changes over the course of a day. If the LRPP RES322is a solar array, the LRPP power output profile may show the LRPP output rise in the morning as the LRPP is exposed to more sunlight, peak at noon, and drop off through the afternoon and evening as the sun sets. In some embodiments, a peak LRPP output may be limited by a transmission capacity of the LRPP interconnection infrastructure350. In other embodiments, the transmission capacity of the LRPP interconnection infrastructure350may be based on the peak LRPP output. In some embodiments, the transmission capacity is no more than 150% of the peak LRPP output. The peak LRPP output is higher than an average LRPP output. The transmission capacity of the LRPP interconnection infrastructure350may be underutilized. For example, if the RES132is a solar array, the peak LRPP output at noon may be much higher than the LRPP output in the morning and in the evening, meaning the transmission capacity of the LRPP interconnection infrastructure350is only fully used at noon and only partially used in the morning and the evening. In some embodiments, an output capacity of the ARPP RES323may be sized based on an LRPP transmission capacity of the LRPP interconnection infrastructure. In some embodiments, the ARPP RES output capacity may be sized to be equal to the LRPP interconnection infrastructure transmission capacity. In other embodiments, the ARPP RES output capacity may be sized such that the ARPP RES323may output sufficient power to fully utilize the LRPP transmission capacity. In yet other embodiments, the ARPP RES output capacity may be sized such that the ARPP RES323may output sufficient power, when combined with the LRPP RES output and the ESS output, to fully utilize the LRPP transmission capacity. The ARPP RES output capacity may be sized such that the ARPP RES323may output sufficient power, when combined with the LRPP RES output and the ESS output, to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. A storage capacity of the ESS329may be based on the interconnection infrastructure transmission capacity and the LRPP power output profile. For example, the ARPP RES output capacity may be sized and the ESS storage capacity may be sized such that the ARPP RES323outputs sufficient power and the ESS329stores and/or outputs sufficient power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. In another example, The ARPP RES output capacity may be sized and the ESS storage capacity may be sized such that the ARPP RES323outputs sufficient power to complement the LRPP power output profile and charge the ESS329so the ESS329can output sufficient power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. The ESS storage capacity is sized to be able to store the ARPP RES output and provide stored power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity. In this example, the ARPP RES323may output sufficient power to complement the LRPP power output profile to fully utilize the LRPP transmission capacity and charge the ESS with sufficient power such that when the ARPP RES323does not output sufficient power to complement the LRPP power output profile, the ESS329may output sufficient power to complement the LRPP power output. In this example, the ARPP RES323may be a solar array which produces power during daylight hours and charges the ESS329. Before and after daylight hours when the ARPP RES323is not producing power, the ESS329may provide stored power to complement the LRPP power output profile. In some embodiments, the ARPP RES323and ESS329are sized together based on the LRPP transmission capacity and the LRPP power output profile. The ARPP RES323and ESS329may be sized such that an ARPP-LRPP combined power output is substantially equal to the LRPP transmission capacity for a target interval. The target interval may be based on the LRPP power output profile. For example, the LRPP power output profile may show the LRPP power output for a day. The target interval may be a portion of the day or the entire day, in which case the ARPP-LRPP combined power output will always be substantially equal to the LRPP transmission capacity. The ARPP RES323may be sized to produce an amount of power equal to the LRPP transmission capacity for the target interval minus an amount of power produced by the LRPP RES322as shown in the LRPP power output profile. The ESS329may be sized to store power generated by the ARPP RES323and output the stored power such that the ARPP-LRPP combined output is substantially equal to the LRPP transmission capacity. In some embodiments, the AEMS321is configured to control the ARPP output such that a variability of the ARPP-LRPP combined output has a lower variability than a variability of the LRPP output. Variability of an output is a measure of how much individual values of the output differ from a moving average of the output or from a pattern associated with the output. The AEMS321may control the ARPP output to counteract the variability of the LRPP output. For example, if the LRPP is a solar array and clouds pass in front of the solar array causing a temporary drop in LRPP output, the AEMS311may raise the ARPP output to adjust for the temporary drop in LRPP output. With the increased ARPP output balancing out the temporary drop in LRPP output, the ARPP-LRPP combined output can remain steady and thus have less variability than the LRPP output. The AEMS311may control the ARPP RES output and the ESS charge/discharge to control the ARPP output. The AEMS311may track the ARPP power output using the ARPP power meter331and track the LRPP power output using the LRPP power meter330. The variability of the LRPP output may be determined in real-time by the LEMS310using the tracked LRPP power output from the LRPP power meter330. In some embodiments, an expected variability of the LRPP output may be determined based on historic LRPP output data and/or the LRPP power output profile, where the LRPP power output profile is an representation of an average LRPP output. The AEMS311may regulate the ARPP output and/or the ESS charge/discharge based on the variability of the LRPP output such that the ARPP-LRPP combined output has a lower variability than a variability of the LRPP output. The AEMS311may adjust inverter setpoints for the ARPP RES inverter325and the ESS inverter327to control the ARPP RES323and the ESS329. The AEMS311may receive feedback from the LRPP power meter330to determine the LRPP output variability and control the ARPP RES323ESS329to counteract the LRPP output variability. The AEMS311may receive feedback from the interconnection infrastructure power meter345to monitor the ARPP-LRPP combined output variability. In some embodiments, the AEMS311is configured to control the ARPP output such that the ARPP-LRPP combined output does not exceed the LRPP interconnection infrastructure transmission capacity. The LRPP output and/or the ARPP-LRPP output may be determined in real time. The AEMS311may regulate the ARPP output and/or the ESS charge/discharge based on the LRPP output such that the ARPP-LRPP combined output does not exceed the LRPP transmission capacity. The AEMS311may track the ARPP power output using the ARPP power meter331and track the LRPP power output using the LRPP power meter330. The AEMS311may track the ARPP-LRPP combined power output using the interconnection infrastructure power meter345. The AEMS311may control the ARPP such that the instantaneous sum of the ARPP output and the LRPP output does not exceed a maximum permitted power flow at the point-of-interconnect (POI) to the grid. The AEMS311may control the ARPP output according to a power sale agreement and/or based on current and expected market pricing for power while ensuring that the ARPP-LRPP combined output does not exceed the LRPP transmission capacity. In some embodiments, the AEMS311may control the ARPP such that a rate of change of the ARPP-LRPP combined power output does not exceed an allowed rate of change at the POI. The AEMS311may control the ARPP such that a ramp-down rate of the ARPP-LRPP combined power output does not exceed a maximum ramp-down rate and that a ramp-up rate of the ARPP-LRPP combined power output does not exceed a maximum ramp-up rate. In some embodiments, the AEMS311and the LEMS310may transmit inverter setpoints of the ARPP and the LRPP to a shared energy management system. The shared energy management system may resolve conflicts arising from independently set inverter setpoints of the ARPP and the LRPP. If the sum of the ARPP output and the LRPP output exceeds the LRPP interconnection infrastructure transmission capacity, the shared energy management system may send a signal to the AEMS311to reduce the ARPP output. The inverter setpoints of the ARPP and the LRPP may be sent to the shared energy management system for approval by the AEMS311and the LEMS310before being applied to inverters of the ARPP and the LRPP. The shared energy management system may compare the ARPP output and the LRPP output such that the ARPP output complements the LRPP output. The shared energy management system may receive inverter setpoints of the ARPP and the LRPP, calculate a combined output based on the received inverter setpoints, compare the combined output to a target output, and adjust the inverter setpoints of the ARPP so the combined output is equal to the target output. The shared energy management system may determine inverter setpoints for inverters of the ARPP and the LRPP based on the transmission capacity, an instantaneous LRPP output, and an instantaneous ARPP output. The shared energy management system may set the ARPP output to be equal to the transmission capacity minus the LRPP output. The shared energy management system may control the ARPP such that the ARPP output does not exceed the transmission capacity minus the LRPP output. FIG.4is an example ARPP connected to an interconnection infrastructure of an LRPP upstream of a transformer of the interconnection infrastructure, where the ARPP is a wind farm, in accordance with one or more embodiments.FIG.4shows the example ARPP ofFIG.2, wherein the LRPP RES422is a wind farm and the ARPP RES is a combination wind/solar farm. AlthoughFIG.2shows the LRPP RES222as a solar array and the ARPP RES223as a solar array, the LRPP RES222and ARPP RES223may be any RES, including, but not limited to, a wind farm, a solar farm, a geothermal plant, a biofuel plant, a tidal force generator, a hydroelectric generator, or any combination of RESs. FIG.5is an example flowchart500illustrating operations for constructing and controlling an ARPP, in accordance with one or more embodiments. Additional, fewer, or different operations may be performed in the method, depending on the embodiment. Further, the operations may be performed in the order shown, concurrently, or in a different order. At510, a transmission capacity of an interconnection infrastructure of a legacy renewable power plant (LRPP) is obtained. The interconnection infrastructure may include a switchyard and local substation, a gen-tie, and a point-of-interconnect (POI) substation. The transmission capacity may be equal to a lowest transmission capacity of transmission capacities of components of the interconnection infrastructure. At520, a power output profile of the LRPP is obtained. In some embodiments, the LRPP power output profile is based on historic data. The LRPP power output profile may be an average of the LRPP output for a plurality of intervals, a representative interval from the plurality of intervals, or a weighted average of the plurality of intervals. For example, the LRPP power output profile may show how the LRPP output changes, on average, over the course of a day. In another example, the LRPP power output profile may show how the LRPP power output has changed historically over the course of a day having certain characteristics, such as time of year, weather forecast, or other characteristics. In other embodiments, the LRPP power output profile is based on a forecast of the LRPP power output. The LRPP power output forecast may be based on irradiance data, weather forecasts, a configuration of the LRPP such as placement of solar arrays, and/or a conversion efficiency of the LRPP. The LRPP power output forecast may be updated based on updated data such as updated forecasts. At530, a renewable energy source (RES) output capacity and an energy storage system (ESS) storage capacity are determined based on the transmission capacity of the LRPP interconnection infrastructure and the power output profile of the LRPP. The RES output capacity and the ESS storage capacity may be determined such that a combined output of the RES, the ESS, and the LRPP are substantially equal to the transmission capacity. The RES output capacity and the ESS storage capacity may be determined such that a combined output of the RES, the ESS, and the LRPP are substantially equal to the transmission capacity for a predetermined interval. For example, the LRPP may be a solar array having a power output profile spanning a day with a maximum output at noon equal to the transmission capacity, but with outputs at other times of day much lower than the transmission capacity. The RES output capacity and the ESS storage capacity may be determined such that the RES can output enough power, and the ESS can store enough power such that the combined power output of the RES, ESS, and LRPP is equal to the transmission capacity all day long. In another example, the RES output capacity and the ESS storage capacity may be determined such that the RES can output enough power, and the ESS can store enough power such that the combined power output of the RES, ESS, and LRPP is equal to the transmission capacity for as long as the LRPP produces power. At540, an add-on renewable power plant (ARPP) is constructed including an RES having the determined RES output capacity and an ESS having the determined ESS storage capacity. The ARPP is added on to the LRPP, such that the ARPP connects to the LRPP interconnection infrastructure. The output of the RES and the ESS may be an ARPP output. The ARPP may be constructed in an added-on state or constructed near the LRPP and then connected when completed. The ARPP may be constructed with safety factors for the RES output capacity and the ESS storage capacity such that the combined output of the ARPP and LRPP is substantially equal to the transmission capacity despite fluctuations in the output of the RES and the LRPP. At550, a controller of the ARPP tracks an ARPP power output and the LRPP output. The ARPP controller may track the ARPP output by tracking an RES output and an ESS charge/discharge or by tracking the ARPP output directly using a meter. The ARPP controller may track the LRPP output using a meter. The ARPP controller may track the RES output, the ESS charge/discharge, and the LRPP output by tracking inverter setpoints of inverters connected to the RES, the ESS, and the LRPP. At560, the ARPP controller controls the ARPP such that an ARPP-LRPP combined power output does not exceed the transmission capacity of the LRPP interconnection infrastructure. Controlling the ARPP may include controlling inverter setpoints of an RES inverter and an ESS inverter. The RES inverter may control the RES output and the ESS inverter may control the ESS charge/discharge. The LRPP may produce an amount of power and the ARPP controller may react to the amount of power such that the ARPP-LRPP combined power output does not exceed the transmission capacity of the LRPP interconnection infrastructure. The ARPP controller may control the ARPP such that the instantaneous sum of the ARPP output and the LRPP output does not exceed a maximum permitted power flow at the point-of-interconnect (POI) to the grid. In some embodiments, the ARPP controller may control the ARPP such that a rate of change of the ARPP-LRPP combined power output does not exceed an allowed rate of change at the POI. The ARPP controller may control the ARPP such that a ramp-down rate of the ARPP-LRPP combined power output does not exceed a maximum ramp-down rate and that a ramp-up rate of the ARPP-LRPP combined power output does not exceed a maximum ramp-up rate. At570, the ARPP controller controls the ARPP such that the ARPP power output complements the LRPP power output. The LRPP may produce an amount of power and the ARPP controller may react to the amount of power to complement the amount of power. For example, if the LRPP power output dips such that an ARPP-LRPP combined power output is no longer equal to the transmission capacity, the ARPP controller may control the ARPP such that the ARPP output increases to make the ARPP-LRPP combined output equal to the transmission capacity. FIG.6is an example flowchart600illustrating operations for connecting an ARPP to an interconnection infrastructure of an LRPP and controlling the ARPP, in accordance with one or more embodiments. Additional, fewer, or different operations may be performed in the method, depending on the embodiment. Further, the operations may be performed in the order shown, concurrently, or in a different order. At610, an ARPP is connected to an LRPP interconnection infrastructure. The ARPP may include an RES and an ESS sized based on the LRPP interconnection infrastructure transmission capacity and the LRPP power output profile, as described herein. The ARPP may be constructed near the LRPP to be connected to the LRPP interconnection infrastructure or may be in a remote location and connected via a transmission line. At620, the ARPP controller controls the ARPP such that a variability of the ARPP-LRPP combined output has a lower variability than the variability of the LRPP output, wherein the ARPP is controlled such that the ARPP-LRPP combined output does not exceed a transmission capacity of the LRPP interconnection infrastructure. The LRPP may produce an amount of power and the ARPP controller may react to the amount of power such that the ARPP-LRPP combined power output does not exceed the transmission capacity of the LRPP interconnection infrastructure. The ARPP controller may react by changing setpoints of the RES inverter and/or the ESS inverter. At630, the ARPP controller tracks the ARPP power output and the LRPP power output. The ARPP controller tracks the ARPP power output and the LRPP power output using meters measuring the power outputs of the ARPP and LRPP and/or by monitoring setpoints of inverters of the ARPP and LRPP. At640, the ARPP controller controls the ARPP such that the ARPP power output complements the LRPP power output. The LRPP may produce an amount of power and the ARPP controller may react to the amount of power to complement the amount of power. For example, if the LRPP power output dips such that an ARPP-LRPP combined power output is no longer equal to the transmission capacity, the ARPP controller may control the ARPP such that the ARPP output increases to make the ARPP-LRPP combined output equal to the transmission capacity. FIG.7is an example output700of an example LRPP, in accordance with one or more embodiments. The “hour” axis may denote hours in a day. The “power” axis may denote output as a percentage of the LRPP interconnection infrastructure transmission capacity. The output700may be a power output profile700of the LRPP. The output700may be an LRPP power output profile showing a weighted average of multiple days of output or a representative day of output. The LRPP may be a solar array. The output700may be zero until sunrise, when the solar array begins to produce power. The output700may rise until it reaches the transmission capacity or an output capacity of the LRPP, at which point it flattens. The output700may fall in the afternoon until it reaches zero around sunset. The output700is zero at night until the following morning. FIG.8is an example combined output800of an example ARPP and an example LRPP, in accordance with one or more embodiments. The “hour” axis may denote hours in a day. The “power” axis may denote output as a percentage of the LRPP interconnection infrastructure transmission capacity. The combined output800may be a combination of an LRPP output810and an ARPP output820. The LRPP output810may be the LRPP output700ofFIG.7.FIG.8may show a combined output900for the ARPP and LRPP ofFIGS.2-4. The ARPP output820may complement the LRPP output810such that the combined output800is consistent and smooth. The ARPP output820may be the output of an ARPP RES and ARPP ESS, where the ARPP ESS is configured to store power produced by the ARPP RES and output the stored power. The ARPP output is the sum of the ARPP RES output and the ARPP ESS charge/discharge. The ARPP RES may be a solar array with an output similar to the LRPP output810. The ARPP ESS may store the ARPP RES output for later use. Around noon, when the LRPP output810is equal to the transmission capacity, the entirety of the ARPP RES output is available to charge the ARPP ESS and the ARPP output820may be zero. The ARPP RES output is either being directed to the grid as ARPP output820, being used to charge the ARPP ESS, split between the grid and the ARPP ESS, or being curtailed. Energy stored in the ARPP ESS may be discharged to the grid as needed. The ARPP RES and ARPP ESS may be tuned to complement the LRPP output810. The ARPP RES and ARPP ESS may be tuned to complement the LRPP output810such that the combined output800provides consistent power for a time interval such as from 4:00 to 21:00. The ARPP RES may be tuned to have an output capacity equal to the LRPP transmission capacity for the time interval minus the LRPP output810for the time interval. The ARPP ESS may be tuned to store the power equal to the ARPP RES output capacity for the time interval minus the ARPP output820for the time interval. The tuned ARPP RES and ARPP ESS may be able to produce and store sufficient power to provide the ARPP output820for the time interval to complement the LRPP output810for the time interval such that the combined output800is consistent for the time interval. FIG.9is another example combined output900of an example ARPP and an example LRPP, in accordance with one or more embodiments.FIG.9may show a combined output900for the ARPP and LRPP ofFIG.8for a day when the LRPP output910is inconsistent.FIG.9may show a combined output900for the ARPP and LRPP ofFIGS.2-4for a day when the LRPP output910is inconsistent. The LRPP output910may be inconsistent due to clouds passing over the solar array of the LRPP, due to maintenance, or other factors. The ARPP output920may be adjusted in real time to complement the LRPP output910, as described herein. The combined output900may not be consistent for the entire time interval of 4:00 to 21:00 as it was inFIG.8. The combined output900may have a priority to maintain consistent output for as long as possible or to maintain consistent output for the time interval as consistently as possible.FIG.9shows the combined output900having a priority to maintain consistent output for as long as possible, maintaining the combined output900at peak output until shortly before 21:00. In an example, afternoon clouds disrupt the LRPP output910between noon and 2:00 pm and between 3:00 pm and 4:00 pm. The ARPP output920may increase to offset the reduced output of the LRPP. The ARPP output920may be able to be increase because the ARPP has greater output capacity than the LRPP and the ARPP includes an ESS having stored energy. The ARPP output920may be reduced due to the clouds as well, meaning that the ESS of the ARPP is fully discharged earlier than it would be if the ARPP output920were not affected by the clouds. However, total power production remains steady through the afternoon and early evening. This is advantageous because a grid operator may be alerted to the reduced ARPP output920and LRPP output910and may plan for additional power output from other sources to be used once the ARPP ESS is fully depleted. FIG.10is another example output1000of an example LRPP, in accordance with one or more embodiments. The LRPP output1000is an output of an LRPP having a solar array incorporating solar trackers. The solar trackers allow the LRPP output1000to rise earlier and reach the peak output earlier in the day, as compared to the output700ofFIG.7. FIG.11is yet another example combined output1100of an example ARPP and an example LRPP, in accordance with one or more embodiments. The combined output1100is a combination of an LRPP output1110and an ARPP output1120. The LRPP output1110may be the LRPP output1000ofFIG.10. The ARPP output1120may complement the LRPP output1110, as described herein. Due to the increased LRPP output1110, the combined output1100may be consistent for longer than the combined output800, about 4:00 to 23:00. In an illustrative embodiment, any of the operations described herein can be implemented at least in part as computer-readable instructions stored on a computer-readable memory. Upon execution of the computer-readable instructions by a processor, the computer-readable instructions can cause a node, such as a computing node or a power plant node, to perform the operations. The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being “operably couplable,” to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components. With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” Further, unless otherwise noted, the use of the words “approximate,” “about,” “around,” “similar,” “substantially,” etc., mean plus or minus ten percent. The foregoing description of illustrative embodiments has been presented for purposes of illustration and of description. It is not intended to be exhaustive or limiting with respect to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents. The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. | 55,750 |
11862981 | DESCRIPTION OF EMBODIMENTS The following describes technical solutions in embodiments of this application with reference to accompanying drawings in embodiments of this application. The following terms “first”, “second”, and the like are merely intended for a purpose of description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by “first”, “second”, or the like may explicitly or implicitly include one or more features. In the descriptions of this application, unless otherwise specified, “a plurality of” means two or more than two. In this application, it should be noted that the term “connection” should be understood in a broad sense unless otherwise expressly specified and limited. For example, the “connection” may be a fixed connection, may be a detachable connection, may be an integral connection; may be a direct connection, or may be an indirect connection implemented by using a medium. In addition, the term “coupled” may be a manner of implementing an electrical connection for signal transmission. The “coupling” may be a direct electrical connection, or may be an indirect electrical connection through an intermediate medium. To enable a person skilled in the art to better understand the technical solutions provided in embodiments of this application, the following first describes an application scenario of the technical solutions with reference to the accompanying drawings. Photovoltaic System Embodiment Embodiments of this application relate to a photovoltaic system. Generally, the photovoltaic system includes an inverter and a plurality of photovoltaic strings. The plurality of photovoltaic strings are connected to an input terminal of the inverter, and the photovoltaic string includes a plurality of photovoltaic modules. To more flexibly configure the photovoltaic modules in the photovoltaic string, a converter may be connected to each photovoltaic module. To be specific, an input terminal of a converter is connected to a corresponding photovoltaic module, and a voltage of the photovoltaic module is an input voltage of the converter. The converter can adjust the input voltage of the converter to adjust the voltage of the photovoltaic module. Generally, the converter is a direct current/direct current DC/DC (Direct Current/Direct Current) converter. The DC/DC converter may include a boost circuit, a buck circuit, or a buck-boost circuit. In this embodiment of this application, an example in which the converter is a buck circuit is used for description. Generally, a converter is also referred to as an optimizer in a photovoltaic system. Working states of the converter are classified into two working modes: a maximum power point tracking (maximum power point tracking, MPPT) mode and an output voltage limiting mode. MPPT mode: In normal cases, the converter only controls the input voltage to work at a maximum power point voltage (Maximum Power Point Voltage, Vmpp) of the photovoltaic module to achieve a maximum output power of the photovoltaic module, and does not control an output voltage. Voltage limiting mode: In some scenarios, for example, the inverter shuts down, an output power of the inverter is limited, or the inverter is not connected to a load, the converter only controls an output voltage to be at a voltage limiting value, and does not control an input voltage. The actual input voltage works at a point that deviates from a Vmpp of the photovoltaic module. It should be understood that the MPPT mode and the voltage limiting mode of the converter are two mutually exclusive working modes. The converter is allowed to switch between the two modes, but the converter can work only in one mode at a time. Because the converter sometimes needs to work in the voltage limiting mode, the converter needs to limit the output voltage, in other words, the output voltage of the converter is set to the voltage limiting value. In the conventional technology, the voltage limiting value is usually set to a fixed value and cannot be changed, and a quantity of converters in the photovoltaic string needs to be set based on the fixed voltage limiting value. For example, a voltage limiting value of each converter is 30 V. If a maximum allowable input voltage of the inverter is 600 V, an upper limit of a quantity of converters connected in series in the photovoltaic string is 600 V/30 V=20. In this case, when the quantity of converters in the photovoltaic string is small, the converters, because of the voltage limiting value, still work in a buck mode, and conversion efficiency is low. In addition, in the conventional technology, a manner in which a voltage limiting value of each converter is set based on a quantity of converters connected in series is further provided. For example, if a quantity of converters in the photovoltaic string is 15, and a maximum allowable input voltage of the inverter is 600 V, the voltage limiting value of each converter is 600 V/15=40 V. However, this manner is applicable to a case in which all the photovoltaic modules in the photovoltaic string are the same model. If the photovoltaic modules in the photovoltaic string include different models, a converter with a high open circuit voltage and a converter with a low open circuit voltage correspond to a same voltage limiting value, and therefore conversion efficiency of the converter with the high open circuit voltage is low. Therefore, in embodiments of this application, to resolve a technical problem in the conventional technology that conversion efficiency of some converters is low because voltage limiting values of all the converters are the same, in the technical solutions provided in embodiments of this application, voltage limiting values of different converters can be set to different values, to make a voltage limiting value of a converter proportional to an open circuit voltage of a photovoltaic module corresponding to the converter. To be specific, when the open circuit voltage of the photovoltaic module connected to the converter is high, a corresponding voltage limiting value is high. When the open circuit voltage of the photovoltaic module connected to the converter is low, a corresponding voltage limiting value is low. The technical solution is applicable not only to a case in which photovoltaic modules in a photovoltaic string have different models, but also to a case in which photovoltaic modules in the photovoltaic string have the same model. In addition, the technical solutions provided in embodiments of this application are applicable not only to a case in which quantities of photovoltaic modules in a plurality of photovoltaic strings are the same, but also to a case in which quantities of photovoltaic modules in a plurality of photovoltaic strings are different. The following describes architectures of a photovoltaic system with reference to accompanying drawings. FIG.1is a schematic diagram of a photovoltaic system according to an embodiment of this application. For ease of description, in this embodiment, an example in which a plurality of photovoltaic strings include at least a first photovoltaic string100and a second photovoltaic string200is used for description. In an actual product, an input terminal of an inverter300may be connected to more photovoltaic strings. The input terminal of the inverter300is not limited to being connected to two photovoltaic strings. It can be seen fromFIG.1that the first photovoltaic string100includes n photovoltaic modules, and the second photovoltaic string200includes m photovoltaic modules. Both m and n are integers greater than or equal to 2, and m and n may be different. To highlight advantages of the technical solutions provided in embodiments of this application, in this embodiment of this application, an example in which m and n are different integers is used for description. In other words, a quantity n of photovoltaic modules included in the first photovoltaic string100and a quantity m of photovoltaic modules included the second photovoltaic string200are different. An input terminal of a converter1-1in the first photovoltaic string100is connected to a photovoltaic module1-1. An input terminal of a converter1-nis connected to a photovoltaic module1-n. An output terminal of the converter1-1to an output terminal of the converter1-nare connected in series and connected to the input terminal of the inverter300. Similarly, an input terminal of a converter2-1in the second photovoltaic string200is connected to a photovoltaic module2-1. An input terminal of a converter2-mis connected to a photovoltaic module2-m. An output terminal of the converter2-1to an output terminal of the converter2-mare connected in series and connected to the input terminal of the inverter300. The inverter300may include two stages, namely, a DC/DC circuit and a direct current/alternating current (DC/AC, Direct Current/Alternating Current) circuit. The inverter300may include a plurality of DC/DC circuits, and the plurality of DC/DC circuits are in a one-to-one correspondence with a plurality of photovoltaic strings. An output terminal of each photovoltaic string is connected to an input terminal of a corresponding DC/DC circuit, and output terminals of a plurality of DC/DC circuits are connected to an input terminal of the DC/AC circuit. In other words, the output terminals of the plurality of DC/DC circuits are connected in parallel and connected to the input terminal of the DC/AC circuit. An output terminal of the inverter300is connected to a power grid400. Generally, the inverter300is a three-phase inverter, and the power grid400is a three-phase alternating current power grid. Alternatively, the inverter300may be a single-phase inverter for household use, and a corresponding power grid400is an alternating current power grid for household use. The following describes a photovoltaic system according to an embodiment of this application with reference toFIG.2. FIG.2is a schematic diagram of another photovoltaic system according to an embodiment of this application. The photovoltaic system provided in this embodiment of this application includes an inverter300, a controller500, and at least two converters. An input terminal of each of the at least two converters is connected to a corresponding photovoltaic module. Output terminals of the at least two converters are connected in series and connected to an input terminal of the inverter. Generally, each photovoltaic string corresponds to at least two converters, each photovoltaic string includes a plurality of photovoltaic strings and a plurality of converters. An input terminal of each converter is connected to a corresponding photovoltaic module. An input terminal of one converter may be connected to one photovoltaic module or a plurality of photovoltaic modules. This is not limited in this embodiment of this application. For ease of description, inFIG.2, an example in which an input terminal of a converter is connected to one photovoltaic module is used for description. It can be seen fromFIG.2that a first photovoltaic string100includes n photovoltaic modules, and a second photovoltaic string200includes m photovoltaic modules. Both m and n are integers greater than or equal to 2, and m and n may be different. To highlight advantages of the technical solutions provided in embodiments of this application, in this embodiment of this application, an example in which m and n are different integers is used for description. In other words, a quantity n of photovoltaic modules included in the first photovoltaic string100and a quantity m of photovoltaic modules included the second photovoltaic string200are different. An input terminal of a converter1-1in the first photovoltaic string100is connected to a photovoltaic module1-1. An input terminal of a converter1-nis connected to a photovoltaic module1-n. An output terminal of the converter1-1to an output terminal of the converter1-nare connected in series and connected to the input terminal of the inverter300. Similarly, an input terminal of a converter2-1in the second photovoltaic string200is connected to a photovoltaic module2-1. An input terminal of a converter2-mis connected to a photovoltaic module2-m. An output terminal of the converter2-1to an output terminal of the converter2-mare connected in series and connected to the input terminal of the inverter300. The controller500sets a voltage limiting value of at least one converter within the at least two converters in one photovoltaic string, so that the at least one converter works based on the voltage limiting value when working in the voltage limiting mode. The voltage limiting value of the at least one converter is proportional to an open circuit voltage of a photovoltaic module connected to the input terminal of the at least one converter, and is inversely proportional to a sum of open circuit voltages of the photovoltaic string in which the converter is located. The sum of open circuit voltages of the photovoltaic string is a sum of open circuit voltages of all photovoltaic modules in the photovoltaic string. For example, for the first photovoltaic string, the sum of open circuit voltages is a sum of open circuit voltages of the n photovoltaic modules1-1to1-n. For example, as shown inFIG.2, a voltage limiting value of the converter1-1is proportional to the open circuit voltage of the photovoltaic module1-1connected to the input terminal of the converter1-1and is inversely proportional to a sum of open circuit voltages of the first photovoltaic string100in which the converter1-1is located. For the converter2-1, a voltage limiting value of the converter2-1is proportional to the open circuit voltage of the photovoltaic module2-1connected to the input terminal of the converter2-1, and is inversely proportional to a sum of open circuit voltages of the second photovoltaic string200in which the converter2-1is located. It is clear that, in the photovoltaic system provided in this embodiment of this application, a voltage limiting value of each converter is no longer restricted to being set to a fixed value. The voltage limiting value of each converter depends on an open circuit voltage of a photovoltaic module connected to the converter, and also depends on a sum of open circuit voltages of a photovoltaic string in which the converter is located. In this way, for the voltage limiting value configured for each converter, the open circuit voltage of the photovoltaic module connected to the converter is fully considered, so that the converter works at high conversion efficiency. For example, for a same photovoltaic string, a photovoltaic module with a high open circuit voltage corresponds to a high voltage limiting value of a converter, and a photovoltaic module with a low open circuit voltage corresponds to a low voltage limiting value of a converter. Voltage limiting values of converters in a same photovoltaic string vary with different parameters of photovoltaic modules. This helps improve conversion efficiency of the converters. The controller in the photovoltaic system provided in this embodiment of this application may be independently disposed, or may be a controller of the inverter. When the controller is the controller of the inverter, the controller may be integrated into a cabinet of the inverter. In addition, each converter has a built-in control function, in other words, each converter may include a processor, and can adjust an input voltage and an output voltage of the converter. The controller may communicate with the converter in a wired manner or a wireless manner, for example, may communicate through power line communication, in other words, power system communication in which a transmission line is used as a transmission medium of a carrier signal. This is cost-effective, secure, and reliable. Embodiments of this application do not limit a manner of controllers and converters in communication. For example, the controller may communicate with each converter, or may communicate with one converter in each photovoltaic string, and then one converter in the photovoltaic string transfers an instruction of the controller to another converter in the same photovoltaic string. The following describes in detail, with reference to accompanying drawings, a detailed process in which a photovoltaic system sets a voltage limiting value for a converter according to an embodiment of this application. FIG.3is a schematic diagram of still another photovoltaic system according to an embodiment of this application. Each photovoltaic string includes at least two converters. In this embodiment of this application, an example in which a first photovoltaic string100includes 16 photovoltaic modules and corresponds to 16 converters is used, and a second photovoltaic string200includes 10 photovoltaic modules and corresponds to 10 converters is used. It is clear that, a quantity of photovoltaic modules included in the first photovoltaic string100and a quantity of photovoltaic modules included in the second photovoltaic string200are different. The technical solution provided in this embodiment may also be applicable to a case in which quantities of photovoltaic modules in the two photovoltaic strings are the same. As shown inFIG.3, in the first photovoltaic string100, an input terminal of a converter1-1is connected to a photovoltaic module1-1, and an input terminal of a converter1-16is connected to a photovoltaic module1-16. In the second photovoltaic string200, an input terminal of a converter2-1is connected to a photovoltaic module2-1, and an input terminal of a converter2-10is connected to a photovoltaic module2-10. The following separately describes parameters of photovoltaic modules in the first photovoltaic string and parameters of photovoltaic modules in the second photovoltaic string. Each of photovoltaic modules1-1to1-8in the first photovoltaic string and photovoltaic modules2-1to2-5in the second photovoltaic string consists of 60 battery units connected in series. Parameters under standard test conditions (STC, Standard Test Conditions) are as follows: Maximum power Pmpp=320 W, maximum power point voltage Vmpp=33.9 V, maximum power point current Impp=9.43 A, open circuit voltage Voc=40.9 V, and short-circuit current Isc=10.02 A. Each of photovoltaic modules1-9to1-16in the first photovoltaic string and photovoltaic modules2-6to2-10in the second photovoltaic string consists of 72 battery units connected in series. Parameters under STC are as follows: Pmpp=400 W, Vmpp=40.6 V, Impp=9.86 A, Voc=49.3 V, and Isc=10.47 A. It can be learned from the foregoing parameters that the first photovoltaic string includes at least a first group of photovoltaic modules (the photovoltaic modules1-1to1-8) and a second group of photovoltaic modules (the photovoltaic modules1-9to1-16). The parameters of the first group of photovoltaic modules are different from the parameters of the second group of photovoltaic modules. The second photovoltaic string includes at least a third group of photovoltaic modules (the photovoltaic modules2-1to2-5) and a fourth group of photovoltaic modules (the photovoltaic modules2-6to2-10). The parameters of the third group of photovoltaic modules are different from the parameters of the fourth group of photovoltaic modules. In this embodiment, to simplify analysis, it is assumed that the system has been split into photovoltaic strings. In other words, an inverter may perform processing on a per-photovoltaic string basis, and conversion efficiency of a converter is 100%. The parameters of the first group of photovoltaic modules are the same as the parameters of the third group of photovoltaic modules, and the parameters of the second group of photovoltaic modules are the same as the parameters of the fourth group of photovoltaic modules. It should be understood that the parameters of the first group of photovoltaic modules may alternatively be different from the parameters of the third group of photovoltaic modules. Similarly, the parameters of the second group of photovoltaic modules may also be different from the parameters of the fourth group of photovoltaic modules. A controller is specifically configured to set a voltage limiting value based on a preset voltage and a sum of open circuit voltages of each photovoltaic string. The preset voltage is less than a maximum allowable input voltage of the inverter. For example, if the maximum allowable input voltage of the inverter is 600 V, the preset voltage may be a value less than but very close to 600 V. A larger value of the preset voltage indicates higher conversion efficiency of a converter. Further, the controller may obtain a limiting proportion of each photovoltaic string by using a ratio of the preset voltage to the sum of open circuit voltages of each photovoltaic string. At least one converter in each photovoltaic string uses a product of an input voltage of the converter and the limiting proportion as the voltage limiting value. An input voltage of each converter can be obtained, and is a voltage of a photovoltaic module connected to an input of the converter. Input voltages of converters vary with different parameters of the converters. Even if limiting proportions of the converters are the same, voltage limiting values corresponding to the converters are different. It should be understood that, in this embodiment of this application, the controller may obtain a voltage limiting value of each converter and send the voltage limiting value of the converter to the converter. However, when there are a large quantity of converters, the number of tasks (task volume) handled by of the controller is excessively large. This affects working efficiency of the controller. The controller may directly send a limiting proportion to a converter, and the converter obtains a voltage limiting value based on the received limiting proportion. Different photovoltaic strings may correspond to different limiting proportions, because the sum of open circuit voltages of each photovoltaic string is different, and a limiting proportion is proportional to a preset voltage, and is inversely proportional to the sum of open circuit voltages of a photovoltaic string. This is expressed by using a formula as follows: Limiting proportion=Preset voltage/Sum of open circuit voltages of a photovoltaic string. For both the photovoltaic strings, the preset voltage is the same, and a difference lies only in the sum of open circuit voltages. For example, the maximum allowable input voltage of the inverter is 600 V, and the preset voltage set by the controller may be 500 V. It should be understood that the preset voltage may alternatively be another value less than 600 V. In this embodiment of this application, 500 V is merely used as an example for description. The following describes two manners of obtaining a sum of open circuit voltages of a photovoltaic string. Manner 1: The controller obtains a sum of open circuit voltages of each photovoltaic string based on a voltage ratio of a plurality of photovoltaic strings and an output voltage of each photovoltaic string. Manner 2: The controller obtains a sum of open circuit voltages of each photovoltaic string based on an open circuit voltage reported by a converter in the photovoltaic string. A specific manner of obtaining a sum of open circuit voltages of a photovoltaic string by a controller is not specifically limited in this embodiment of this application, and another manner other than the foregoing two manners may be used. The following specifically describes the manner 1 of obtaining a sum of open circuit voltages of a photovoltaic string. The controller may send a voltage ratio K1=0.5 to the first photovoltaic string and the second photovoltaic string in a multicast manner, to control output voltages of converters in the first photovoltaic string and the second photovoltaic string. The controller sends the voltage ratio to the first photovoltaic string and the second photovoltaic string in the multicast manner. The inverter directly sends the voltage ratio to the converters in the photovoltaic strings in a multicast manner without obtaining a quantity of converters in each photovoltaic string in advance. This manner of delivering a control instruction is simple and fast. It should be understood that a value of K1 should be less than 1, and a principle of setting K1 is to ensure that overvoltage of an input voltage of the inverter does not occur, to be specific, to ensure that the input voltage of the inverter is less than 600 V, and that the input voltage of the inverter is as high as possible to improve precision of calculating a sum of open circuit voltages of a photovoltaic string. For example, K1 may be 0.5, 0.6, 0.4, 0.3, or the like, and a person skilled in the art can select the value based on an actual requirement. K1 of different photovoltaic strings may be the same or different. In this embodiment, an example in which K1 of the first photovoltaic string and K1 of the second photovoltaic string are the same is used for description. For example, after receiving K1, the converter in the first photovoltaic string100controls an output voltage to be equal to an input voltage*K1. As shown inFIG.3, output voltages of the converters1-1to1-8in the first photovoltaic string100are 40.9 V*0.5=20.45 V. Output voltages of the converters1-9to1-16in the first photovoltaic string200are 49.3 V*0.5=24.65 V. A sum of output voltages of the first photovoltaic string is 20.45 V*8+24.65 V*8=360.8 V. It should be noted that the foregoing only describes the output voltages of the converters by using a calculation process. Because the voltage ratio sent by the controller is 0.5, each converter controls the output voltage of the converter based on the voltage ratio of 0.5. However, a sum of open circuit voltages of the photovoltaic string finally obtained by the controller is not what is obtained through the foregoing calculation of the converters, but the input voltage of the inverter collected by the controller. The converters corresponding to the photovoltaic strings are connected in series to form a converter string. The converter string is connected to the input terminal of the inverter, and the input voltage of the inverter is an output voltage of the converter string. In this case, the system is in an initial state, and the inverter is not connected to the grid for power generation. Therefore, an output power of the photovoltaic module is approximately 0 W, and an output voltage of the photovoltaic module is approximately the open circuit voltage. The open circuit voltage of the photovoltaic module varies with factors such as ambient temperature, irradiation, and the like. In this embodiment, only an open circuit voltage under STC is used for description. Based on a voltage of 360.8 V of the sampled converters 1 to 16 connected in series, the controller may calculate the sum of open circuit voltages of the first photovoltaic string to be the collected input voltage/K1=360.8 V/K1=721.6 V. It is clear that, the sum of open circuit voltages of the first photovoltaic string is 721.6 V, and exceeds the maximum allowable input voltage of the inverter, namely, 600 V. Therefore, the converter of the first photovoltaic string needs to limit the output voltage. Similarly, each converter in the second photovoltaic string controls an output voltage based on the received voltage ratio K1=0.5. The following describes an output voltage of each converter in the second photovoltaic string. As shown inFIG.3, output voltages of the converters2-1to2-5in the second photovoltaic string200are 40.9 V*0.5=20.45 V. Output voltages of the converters2-6to2-10in the second photovoltaic string200are 49.3 V*0.5=24.65 V. A sum of output voltages of the second photovoltaic string is 20.45 V*5+24.65 V*5=225.5 V. The foregoing merely describes, through calculation, that each converter outputs a voltage based on the ratio of K1=0.5. However, similar to the first photovoltaic string, a sum of open circuit voltages of the second photovoltaic string that the controller obtains is obtained by sampling a voltage after the converters of the second photovoltaic string are connected in series, and an obtained sampled voltage is 225.5 V. Based on the sampled input voltage of 225.5 V, the inverter obtains the sum of open circuit voltages of the second photovoltaic string=225.5 V/K1=451 V. The foregoing controller obtains the sum of open circuit voltages of the first photovoltaic string and the sum of open circuit voltages of the second photovoltaic string. The following describes a process in which the inverter obtains a limiting proportion based on the preset voltage and the sum of open circuit voltages of each photovoltaic string. It should be understood that preset voltages corresponding to the first photovoltaic string and the second photovoltaic string are the same, but the sum of open circuit voltages corresponding to the first photovoltaic string and the sum of open circuit voltages corresponding to the second photovoltaic string are different. Therefore, a limiting proportion corresponding to the first photovoltaic string and a limiting proportion corresponding to the second photovoltaic string are different. The converter in each photovoltaic string limits the output voltage based on a limiting proportion corresponding to the converter. The following uses an example in which the preset voltage set by the controller is 500 V for description. The limiting proportion K21 of the first photovoltaic string equals the preset voltage/the sum of open circuit voltages of the first photovoltaic string=500 V/721.6 V=0.6929. The limiting proportion K22 of the second photovoltaic string equals the preset voltage/the sum of open circuit voltages of the second photovoltaic string=500 V/451 V=1.1086. The controller may deliver the limiting proportion corresponding to each photovoltaic string to each converter in a multicast manner. The controller is specifically configured to send the limiting proportion of the first photovoltaic string to at least one converter in the first photovoltaic string through power line communication, and send the limiting proportion of the second photovoltaic string to at least one converter in the second photovoltaic string, so that the at least one converter in the first photovoltaic string sets a corresponding voltage limiting value based on the limiting proportion of the first photovoltaic string, and the at least one converter in the second photovoltaic string sets a corresponding voltage limiting value based on the limiting proportion of the second photovoltaic string. A parameter delivered by the controller to each converter is a limiting proportion, and a voltage limiting value of each converter is obtained based on the limiting proportion and an open circuit voltage of a photovoltaic module connected to the converter. First, the voltage limiting value of each converter in the first photovoltaic string is described. Each converter in the first photovoltaic string receives the limiting proportion K21, and sets an output voltage limiting value to an input voltage*K21. As shown inFIG.4, voltage limiting values of converters1-1to1-8in the first photovoltaic string100are 40.9 V*0.6929=28.34 V. Voltage limiting values of converters1-9to1-16in the first photovoltaic string100are 49.3 V*0.6929=34.16 V. A limiting voltage of the first photovoltaic string is 28.34 V*8+34.16 V*8=500 V. Second, the voltage limiting value of each converter in the second photovoltaic string is described. Each converter in the second photovoltaic string receives the limiting proportion K22, and sets an output voltage limiting value to an input voltage*K22. As shown inFIG.4, voltage limiting values of converters2-1to2-5in the second photovoltaic string200are 40.9 V*1.1086=45.34 V. Voltage limiting values of converters2-6to2-10in the second photovoltaic string200are 49.3 V*1.1086=54.65 V. A limiting voltage of the second photovoltaic string is 45.34 V*5+54.65 V*5=500 V. It can be learned from the foregoing analysis that the limiting proportion is proportional to the preset voltage and inversely proportional to the sum of open circuit voltages of the photovoltaic string. To increase the limiting proportion, the preset voltage may be increased, so that the limiting proportion is increased. In this way, the converter can work at a high step-down ratio. This helps improve conversion efficiency of the converter. In addition, if the voltage limiting value is higher than the input voltage of the converter, it indicates that the voltage limiting value does not work, and the converter works in a direct-through mode. This helps improve conversion efficiency of the converter, and helps improve electric energy conversion efficiency of the photovoltaic system. If the limiting proportion needs to be increased, the preset voltage needs be set as high as possible, and the preset voltage can be very close to the maximum allowable input voltage of the inverter, provided that overvoltage of the input terminal of the inverter does not occur. In the photovoltaic system provided in this embodiment of this application, not only an open circuit voltage of a corresponding photovoltaic module, but also a sum of open circuit voltages of a photovoltaic string in which the converter is located are considered for a voltage limiting value of each converter. Therefore, the voltage limiting value is proportional to the open circuit voltage of the photovoltaic module so that the converter can maximize conversion efficiency, and the voltage limiting value is set to be as large as possible. In addition, the voltage limiting value is inversely proportional to the sum of open circuit voltages of the photovoltaic string, so that the voltage obtained by connecting the converters in series does not exceed the maximum allowable voltage value of the inverter. The photovoltaic system provided in this embodiment of this application may further adjust the voltage limiting value based on a working status of the inverter, specifically, reduce the voltage limiting value. For example, in a possible implementation, the controller sends a modification coefficient to a converter in each photovoltaic string in a multicast manner, and the converter corrects the voltage limiting value based on the modification coefficient, where the modification coefficient is less than 1. In another case, the controller directly corrects the limiting proportion corresponding to each photovoltaic string based on the modification coefficient, sends the corrected limiting proportion to each photovoltaic string in a multicast manner, and after receiving the corrected limiting proportion, the converter in each photovoltaic string recalculates the voltage limiting value. The control output voltage is obtained based on a recalculated voltage limiting value. The foregoing working status of the inverter may be that the inverter works abnormally. For example, a working abnormality is that a temperature of the inverter exceeds a preset threshold. Specifically, a temperature sensor may be disposed inside a cabinet of the inverter. When the temperature measured by the temperature sensor exceeds the preset threshold, the controller may send a modification coefficient to at least one converter in each photovoltaic string in a multicast manner, where the modification coefficient is used for reducing the voltage limiting value. When the inverter is connected to the grid for power generation, and the inverter is derated due to overtemperature because of some reason(s), for example, because an input voltage of the inverter is high, the input voltage of the inverter needs to be reduced so that the inverter is not derated due to overtemperature. An example in which the modification coefficient K3 sent by the controller in the multicast manner is 0.8 is used for description in the following descriptions. The modification coefficient is less than 1, to reduce the voltage limiting value. A smaller modification coefficient indicates a larger decrease in the voltage limiting value. For example, when the temperature of the inverter greatly exceeds the preset threshold, it indicates that the temperature of the inverter is excessively high, and the voltage limiting value needs to be greatly reduced. In this case, a smaller modification coefficient may be set. FIG.5is a schematic diagram of yet another photovoltaic system according to an embodiment of this application. The inverter delivers a control instruction K3=0.8 to the first photovoltaic string in the multicast manner, to adjust the voltage limiting value of the converter in the first photovoltaic string. After receiving K3, each converter in each photovoltaic string reduces the voltage limiting value to 80% of the original voltage limiting value. Voltage limiting values of converters1-1to1-8in the first photovoltaic string100are 28.34 V*0.8=22.67 V. Voltage limiting values of converters1-9to1-16in the first photovoltaic string100are 34.16 V*0.8=27.33 V. After the converter in the first photovoltaic string100adjusts the voltage limiting value, the limiting voltage of the first photovoltaic string100is 22.67 V*8+27.33 V*8=400 V. That the converter in the second photovoltaic string200updates the voltage limiting value is the same as the process of the first photovoltaic string100, and is specifically as follows: Voltage limiting values of converters2-1to2-5in the second photovoltaic string200are 45.34 V*0.8=36.27 V. Voltage limiting values of converters2-6to2-10in the second photovoltaic string200are 54.65 V*0.8=43.72 V. The limiting voltage of the second photovoltaic string200is 36.27 V*5+43.72 V*5=400 V. The foregoing is merely an example in which the modification coefficient K3=0.8. During actual application, the limiting proportion K3 may be adjusted based on an actual step-down, and limiting proportions K3 of different photovoltaic strings may be the same or different. The foregoing descriptions are merely provided by using an example in which the modification coefficients of the photovoltaic strings are the same. It can be learned from the foregoing results that decrease in the voltage limiting value of the converter inevitably leads to decrease in the output voltage of the converter. Therefore, the input voltage of the inverter is decreased, and the inverter is not derated due to overtemperature. The foregoing embodiments describe the manner of setting the voltage limiting value of the converter in the photovoltaic system. That the converter may have two working modes, namely, the voltage limiting mode and the MPPT mode is also described above. Generally, the converter works in the MPPT mode. The following describes how to obtain an output PV curve of the converter on the premise that overvoltage of the input voltage of the inverter does not occur. When the converter includes a buck circuit, in other words, when the converter is a buck converter, the converter controls an output PV curve of the converter based on a PV curve of the connected photovoltaic module and a corresponding voltage limiting value. The following describes the output PV curve of the converter in detail with reference to the accompanying drawings. A specific control policy of the converter is as follows: An output PV curve of the converter is partially similar to an output PV curve of the photovoltaic module, in other words, voltage limiting of the converter is implemented by simulating an output feature of the photovoltaic module, so that the converter can be equivalent to a photovoltaic module. In other words, from a perspective of the inverter, the photovoltaic module and the converter may be considered as a new photovoltaic module, so that an existing MPPT control policy of the inverter can be adapted when the output voltage of the converter is limited, and stability of the photovoltaic system can be ensured. The following continues to use the example of two photovoltaic strings. First, the first photovoltaic string is described. Refer toFIG.6toFIG.8.FIG.6is an output PV curve of the converters1-1to1-8in the first photovoltaic string and a PV curve of the photovoltaic modules1-1to1-8according to an embodiment of this application.FIG.7is a diagram of an output PV curve of the converters1-9to1-16in the first photovoltaic string and a PV curve of the photovoltaic modules1-9to1-16according to an embodiment of this application.FIG.8is a diagram of an output PV curve of the first photovoltaic string according to an embodiment of this application. The curve ABF inFIG.6is the PV curve of the photovoltaic modules1-1to1-8, and the curve CDEF inFIG.6is the output PV curve of the converters1-1to1-8. The curve ABF inFIG.7is the PV curve of the photovoltaic modules1-9to1-16, and the curve CDEF inFIG.7is the output PV curve of the converters1-9to1-16. The curve CDEF inFIG.8may be obtained as the PV curve of the first photovoltaic string by integratingFIG.6andFIG.7. InFIG.6, because the curve ABF is the PV curve of the photovoltaic modules1-1to1-8, the curve is known. The point C is the voltage limiting value of the converters1-1to1-8, and is also known. In this way, the curve CD can be obtained based on the curve AB and the point C: a ratio of a voltage corresponding to the CD curve to a voltage corresponding to the AB curve is the same.FIG.7is similar. Therefore, the output PV curve of the converter is obtained by using the PV curve of the photovoltaic string and the voltage limiting value of the converter, and the PV curve of the entire photovoltaic string can be obtained by superposing output PV curves of all the converters in the photovoltaic string, in other words, the PV curve of the first photovoltaic string shown inFIG.8can be obtained based onFIG.6andFIG.7. The following calculation is continued by using the data provided in the foregoing embodiment. An existing MPPT control policy of the inverter can ensure that the output voltage of the first photovoltaic string is stable at the point D, and the output voltage of the first photovoltaic string is 22.47 V*8+28.13 V*8=404.8 V, and an output current is 14.23 A. A point for stable working of the converters1-1to1-8is as follows: an input voltage/input current is 33.9 V/9.43 A, an output voltage/output current is 22.47 V/14.23 A, the converter works in the buck mode, and a step-down ratio is 0.6628. A point for stable working of the converters1-9to1-16is as follows: an input voltage/input current is 40.6 V/9.86 A, an output voltage/output current is 28.13 V/14.23 A, the converter works in the buck mode, and a step-down ratio is 0.6929. The following describes the PV curve of the second photovoltaic string. Refer toFIG.9toFIG.11.FIG.9is an output PV curve of the converters2-1to2-5in the second photovoltaic string and a PV curve of the photovoltaic modules2-1to2-5according to an embodiment of this application.FIG.10is a diagram of an output PV curve of the converters2-6to2-10in the second photovoltaic string and a PV curve of the photovoltaic modules2-6to2-10according to an embodiment of this application.FIG.11is a diagram of an output PV curve of the second photovoltaic string according to an embodiment of this application. The following calculation is continued by using the data provided in the foregoing embodiment. An existing MPPT control policy of the inverter can ensure that the output voltage of the second photovoltaic string is stable at the point D, and the output voltage of the second photovoltaic string is 32.42 V*5+40.6 V*5=365.1 V, and an output current is 9.86 A. A point for stable working of the converters2-1to2-5is as follows: an input voltage/input current is 33.9 V/9.43 A, an output voltage/output current is 32.42 V/9.86 A, the converter works in the buck mode, and a step-down ratio is 0.9563. A point for stable working of the converters2-6to2-10is as follows: an input voltage/input current is 40.6 V/9.86 A, an output voltage/output current is 40.6 V/9.86 A, the converter works in the direct-through mode, and a step-down ratio is 1.0. In the photovoltaic system provided in this embodiment of this application, the voltage limiting values of the converters may be set differently based on a difference in configurations of photovoltaic modules. This improves conversion efficiency of the converters. Further, the photovoltaic string can be better controlled by using a PV curve obtained based on a differentiated voltage limiting value, to perform maximum power tracking. This can further improve conversion efficiency of the entire photovoltaic string and improve energy conversion efficiency of the photovoltaic system. Method Embodiment According to the photovoltaic system provided in the foregoing embodiments, an embodiment of this application further provides a photovoltaic system control method. The following describes in detail with reference to accompanying drawings. It should be understood that the control method provided in embodiments of this application is applicable to the photovoltaic system provided in the foregoing embodiments, and the photovoltaic system includes an inverter, a controller, and at least two converters. Output terminals of the at least two converters are connected in series and connected to an input terminal of the inverter. Each photovoltaic string corresponds to at least two converters. An input terminal of each of the at least two converters is connected to a corresponding photovoltaic module. Each photovoltaic string corresponds to at least two converters. For example, an example in which there are two photovoltaic strings is used. Refer toFIG.2. Details are not described herein again. The photovoltaic system control method provided in this embodiment includes: setting a voltage limiting value of at least one corresponding converter of the at least two converters, so that the at least one converter works based on the voltage limiting value when working in a voltage limiting mode, where the voltage limiting value of the at least one converter is proportional to an open circuit voltage of a photovoltaic module connected to an input terminal of the converter, and is inversely proportional to a sum of open circuit voltages of a photovoltaic string in which the converter is located. The foregoing control method may be performed by a controller, where the controller may be independently disposed, or may be a controller of the inverter. When the controller is the controller of the inverter, the controller may be disposed inside a cabinet of the inverter. The controller sets the voltage limiting value of the at least one converter of the at least two converters, so that the at least one converter works based on the voltage limiting value when working in the voltage limiting mode. The voltage limiting value of the at least one converter is proportional to the open circuit voltage of the photovoltaic module connected to the input terminal of the at least one converter, and is inversely proportional to the sum of open circuit voltages of the photovoltaic string in which the converter is located. For example, as shown inFIG.2, the voltage limiting value of the converter1-1is proportional to the open circuit voltage of the photovoltaic module1-1connected to the input terminal of the converter1-1and is inversely proportional to the sum of open circuit voltages of the first photovoltaic string100in which the converter1-1is located. For the converter2-1, the voltage limiting value of the converter2-1is proportional to the open circuit voltage of the photovoltaic module2-1connected to the input terminal of the converter2-1, and is inversely proportional to the sum of open circuit voltages of the second photovoltaic string200in which the converter2-1is located. It is clear that, according to the photovoltaic system control method provided in this embodiment of this application, a voltage limiting value of each converter is no longer restricted to being set to a fixed value. The voltage limiting value of each converter depends on an open circuit voltage of a photovoltaic module connected to the converter, and also depends on a sum of open circuit voltages of a photovoltaic string in which the converter is located. In this way, for the voltage limiting value configured for each converter, the open circuit voltage of the photovoltaic module connected to the converter is fully considered, so that the converter works at high conversion efficiency. For example, for a same photovoltaic string, a photovoltaic module with a high open circuit voltage corresponds to a high voltage limiting value of a converter, and a photovoltaic module with a low open circuit voltage corresponds to a low voltage limiting value of a converter. Voltage limiting values of converters in a same photovoltaic string vary with different parameters of photovoltaic modules. This helps improve conversion efficiency of the converters. The following describes in detail, with reference to accompanying drawings, a process of setting a voltage limiting value by using a control method according to an embodiment of this application. FIG.12is a flowchart of a control method according to an embodiment of this application. S1201: Obtain a sum of open circuit voltages of each photovoltaic string based on a voltage ratio of a plurality of photovoltaic strings and an output voltage of each photovoltaic string. The voltage ratio is K1 described in the foregoing photovoltaic system embodiments. Details are not described herein again. An output voltage of each photovoltaic string may be obtained through collection. For example, an inverter collects an output voltage of a photovoltaic string connected to the inverter. Divide the output voltage of each photovoltaic string by the voltage ratio to obtain the sum of open circuit voltages of the photovoltaic string. In addition, in this embodiment of this application, the sum of open circuit voltages of each photovoltaic string may be alternatively obtained based on an open circuit voltage reported by a converter in the photovoltaic string. S1202: Obtain a limiting proportion of each photovoltaic string based on a preset voltage and the sum of open circuit voltages of the photovoltaic string. In one embodiment, the preset voltage needs to be less than a maximum input voltage of the inverter to ensure that overvoltage of an input voltage of the inverter does not occur. A ratio of the preset voltage to the sum of open circuit voltages of the photovoltaic string is the limiting proportion corresponding to the photovoltaic string. It can be learned that the limiting proportion of each photovoltaic string is inversely proportional to the sum of open circuit voltages of the photovoltaic string. S1203: Send the limiting proportion of each photovoltaic string to at least one converter in the photovoltaic string in a multicast manner, so that the at least one converter in each photovoltaic string sets a voltage limiting value based on the limiting proportion of the converter. The voltage limiting value of each converter is obtained by multiplying the limiting proportion of each converter and an open circuit voltage of the photovoltaic string connected to the converter. It should be understood that limiting proportions of different photovoltaic strings may be different, and open circuit voltages corresponding to different converters may be different. That the controller sends the limiting proportion of each photovoltaic string to the photovoltaic string in a multicast manner has an advantage that a quantity of converters in each photovoltaic string does not need to be known in advance. In a specific implementation, each photovoltaic string corresponds to at least two converters. The setting a voltage limiting value of at least one corresponding converter of the at least two converters specifically includes:setting the voltage limiting value based on the preset voltage and the sum of open circuit voltages of each photovoltaic string. In a possible implementation, the limiting proportion of each photovoltaic string may be obtained by using a ratio of the preset voltage to the sum of open circuit voltages of the photovoltaic string. In this way, the limiting proportion of each photovoltaic string can be obtained. The limiting proportion of each photovoltaic string is sent to at least one converter in each photovoltaic string, where the at least one converter in each photovoltaic string uses a product of an input voltage of the converter and the limiting proportion as the voltage limiting value. An input voltage of each converter can be obtained, and is a voltage of a photovoltaic module connected to an input of the converter. Input voltages of converters vary with different parameters of the converters. Even if limiting proportions of the converters are the same, voltage limiting values corresponding to the converters are different. The preset voltage is less than a maximum allowable input voltage of the inverter. In a specific implementation, obtaining a limiting proportion of each photovoltaic string based on a preset voltage and the sum of open circuit voltages of the photovoltaic string, so that at least one converter in each photovoltaic string sets a voltage limiting value based on the limiting proportion of the at least one converter in each photovoltaic string specifically includes: sending the limiting proportion of the first photovoltaic string to at least one converter in the first photovoltaic string through power line communication, and sending the limiting proportion of the second photovoltaic string to at least one converter in the second photovoltaic string, so that the at least one converter in the first photovoltaic string sets a corresponding voltage limiting value based on the limiting proportion of the first photovoltaic string, and the at least one converter in the second photovoltaic string sets a corresponding voltage limiting value based on the limiting proportion of the second photovoltaic string. The photovoltaic system control method provided in this embodiment of this application further includes: when the inverter works abnormally, sending a modification coefficient to at least one converter in each photovoltaic string in a multicast manner, where the modification coefficient is used for reducing the voltage limiting value, and the modification coefficient is less than 1. The foregoing working status of the inverter may be that the inverter works abnormally. For example, a working abnormality is that a temperature of the inverter exceeds a preset threshold. Specifically, a temperature sensor may be disposed inside a cabinet of the inverter. When the temperature measured by the temperature sensor exceeds the preset threshold, the controller may send a modification coefficient to at least one converter in each photovoltaic string in a multicast manner, where the modification coefficient is used for reducing the voltage limiting value. When the inverter is connected to the grid for power generation, and the inverter is derated due to overtemperature because of some reasons, for example, because an input voltage of the inverter is high, the input voltage of the inverter needs to be reduced so that the inverter is not derated due to overtemperature. When the converter includes a buck circuit, in other words, when the converter is a buck converter, the converter controls an output PV curve of the converter based on a PV curve of the connected photovoltaic module and a corresponding voltage limiting value. For details, refer to descriptions inFIG.6toFIG.11. According to the control method provided in this embodiment of this application, the voltage limiting values of the converters may be set differently based on a difference in configurations of photovoltaic modules. This improves conversion efficiency of the converters. Further, the photovoltaic string can be better controlled by using a PV curve obtained based on a differentiated voltage limiting value, to perform maximum power tracking. This can further improve conversion efficiency of the entire photovoltaic string and improve energy conversion efficiency of the photovoltaic system. It should be understood that in this application, “at least one (item)” refers to one or more. The term “and/or” is used to describe an association relationship between associated objects, and indicates that three relationships may exist. For example, “A and/or B” may indicate the following three cases: Only A exists, only B exists, and both A and B exist, where A and B may be singular or plural. The character “/” generally represents an “or” relationship between the associated objects. “At least one of the following items (pieces)” or a similar expression thereof indicates any combination of these items, including a single item (piece) or any combination of a plurality of items (pieces). For example, at least one of a, b, and c may indicate a, b, c, “a and b”, “a and c”, “b and c”, or “a, b, and c”, where a, b, and c may be singular or plural. The foregoing descriptions are merely example embodiments of this application, and are not intended to limit this application in any form. Although the example embodiments of this application are disclosed above, embodiments are not intended to limit this application. By using the method and the technical content disclosed above, any person skilled in the art can make a plurality of possible changes and modifications on the technical solutions of this application, or amend the technical solutions thereof to be embodiments with equal effects through equivalent variations without departing from the technical solutions of this application. Therefore, any amendment, equivalent variation, and modification made on the above embodiments according to the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application. The scope of the inventions herein are determined by the claims taken as a whole. | 58,571 |
11862982 | DETAILED DESCRIPTION The invention will be further described below in conjunction with specific embodiments. The following embodiments are merely used to more clearly explain the technical solutions of the invention, and should not be construed as limiting the protection scope of the invention. As mentioned above, existing methods for primary frequency regulation of new energy power stations have the problems of poor frequency regulation precision, low frequency regulation speed, and low success rate of primary frequency regulation of the new energy power stations due to aging of communication devices of part of the new energy power stations. To solve the aforementioned problems, the invention provides a networked control method for primary frequency regulation of a new energy power station, which starts primary frequency regulation when a system frequency is out of a primary frequency regulation dead zone, so as to maintain the frequency of a power grid stable. The method predicts the primary frequency regulation potential of the new energy power station through a prediction algorithm based on a source-grid-load-storage networked cloud decision control system platform, and designs, by taking into account of generating costs of units of the new energy power station, an online rolling optimization method based on model predictive control to allocate primary frequency regulation power of the power generation units of the new energy power station. FIG.1illustrates a flow diagram of a networked control method for primary frequency regulation of a new energy power station according to one embodiment of the invention. As shown inFIG.1, the networked control method for primary frequency regulation of a new energy power station comprises at least the following steps: Step11, primary frequency regulation predictive values of power generation units of a new energy power station are determined according to historical operating data of the new energy power station. In different embodiments, the primary frequency regulation predictive values of the power generation units may be determined in different specific ways. For example, in one embodiment, the primary frequency regulation potential of the power generation units may be predicted through a least squares support vector machine based on historical operating data of the new energy power station. This specification has no limitation in the specific ways of determining the primary frequency regulation predictive values. In one embodiment, the historical operating data comprises one or more of historical active power data in at least 24 hours, light intensity data in at least 24 hours, and wind velocity data in at least 24 hours. Step12, according to the primary frequency regulation predictive values, optimal control sequences of inverters of the power generation units at different times are determined through an online rolling optimization method based on a pre-established inverter active power model, wherein the optimal control sequences comprise multiple control quantities of active power of the inverters. Specifically, on one embodiment, the units of the new energy power station transmit power to, a busbar through inverters, and to ensure that the power of the inverters is adjustable during primary frequency regulation, the inverters should operate in a PQ mode. In one example, an equivalent mathematical model of the inverters in the PQ mode may be established to obtain operating properties of the units of the new energy power station. As shown inFIG.2, a control loop of the inverters in the PQ mode is composed of an outer power loop and an inner current loop on the dq coordinate axes, and without regard to disturbance on the q coordinate axes, active power and reactive power output by the inverters may be calculated according to formula (1): {Pdg=32uod·iodQdg=-32uod·ioq(1) In formula (1), uodis a d-axis component of output port voltage of the inverters, iodand ioqare d-axis component and q-axis component of output port current of the inverters respectively, and Pdgand Qdgare the active power and reactive power output by the inverters respectively. As shown inFIG.3, a delay from receipt of a control instruction by the inverters to execution of the control instruction by the inverters may be equivalent to a one-order inertia link, and is represented by a time constant Td. Time constants Tinpand Tinqare used to represent dynamic response properties of the inner current loop. So, in one example, an equivalent mathematical model of the active power output by the inverters of the new energy power station in the PQ mode may be expressed as: {ΔPref=11+sTdΔPref*Λiod=11+sTinp(kpp+kipS)(ΔPref-ΔPdg)ΔPdg=3uod2ΔiodΔPint=ΔPref-ΔPdgS(2) In formula (2), ΔPref*is a difference between reference power and present power of the inverters, ΔPrefis a difference between actual reference power and the present power of the inverters, Tdis a delay from receipt of a control instruction by the inverters to execution of the control instruction by the inverters, Δiodis a difference between a d-axis current component at a present time and a d-axis current component at a previous time of the inverters, Tinpis the time constant of the inner current loop of the active power, kppand kipare a proportional coefficient and an integral coefficient of an outer power loop PI controller respectively, uodis the d-axis component of the output port voltage of the inverters, ΔPdgis a difference between output power at the present time and output power at the previous time of the inverters, uodis a d-axis component of output port voltage of the inverters, ΔPintis an integral of a difference between ΔPrefand ΔPdg, and s is a Laplace operator. An equivalent mathematical model of the output reactive power of the inverters in the PQ mode can be obtained in the similar way. Because only the active power needs to be changed when the new energy power station participates in primary frequency regulation, only a model for controlling the active power is established in the invention. A state-space model established according to formula (2) may be as follows: Δ{dot over (x)}cp=AcpΔxcp+BcpΔucp(3) Wherein, Δxcp=[ΔPdgΔPintΔiodΔPref]T,Acp=[0032uod0-1001-kppTinpkipTinp-1TinpkppTinp-1Td000],Bcp=[000-1Td],Δucp=[ΔPref*] Formula (3) is discretized to obtain a mathematical model of the active power output by the inverters in a discrete time: x(k+1)=Ax(k)+Bu(k) (4) In formula (4), x(k)=[ΔPdg(k)ΔPint(k)Δiod(k)ΔPref(k)]T, ΔPdg(k) is a difference between output power at a time k and output power at a previous time of the inverters, Δiod(k) is a difference between a d-axis current component at the time k and the d-axis current component at the previous time of the inverters, ΔPref(k) is a difference between the actual reference power and the power at the time k of the inverters, ΔPint(k) is an integral of a difference between ΔPref(k) and ΔPdg(k), u(k)=[ΔPref*(k)], ΔPref*(k) is a difference between the reference power and the power at the time k of the inverters, A=eAcPTp,B=∫0TpeAcpτBcpdτ, and Tpis a sampling time. In one embodiment, based on the mathematical model of the active power output by the inverters in the PQ mode, a primary frequency regulation power allocation method based on model predictive control is proposed. For example, if primary frequency regulation is started when a system frequency is lower than a rated frequency, an objective function for predictive control may be expressed as: min∑j=1Np∑i=1Nλi(k)Φi(k+j❘"\[LeftBracketingBar]"k)(5) In formula (5), Npis a predictive domain length, N is the number of the power generation units of the new energy power station, λi(k) is a weight coefficient of an ithpower generation unit, Φi(k)=−biΔPi(k),bi={0,1} is a cost function of the ithpower generation unit, and ΔPi(k) is a power variation of the power generation unit at the time k with respect to a time k−1; Φi(k+j|k) represents a Φivalue at a time k+j predicted at the time k. The objective function expressed by formula (5) is constrained by the following conditions: λi(k)=Ci(k)ΔPimaxΔPtotal(6)ΔPtotal=∑i=1NΔPimax(7)∑i=1NPi(k)=ΔP(8)ΔP=KΔf(9)ΔPimin≤ΔPi(k)≤ΔPimax,i=1,2…N(10)x(k+1)=Ax(k)+Bu(k)(11) In formula (6), Ci(k) is a confidence of the ithpower generation unit at the time k, and an initial value of Ci(k) is 1; ΔPimaxand ΔPiminare respectively an upper limit and a lower limit of the primary frequency regulation predictive values calculated in Step11, ΔP is total power required for the new energy power station to participate in primary frequency regulation, ΔPtotalis a total predictive value for the new energy power station to participate in primary frequency regulation, Pi(k) is active power of the ithpower generation unit at the time k, Δf is a system frequency deviation, and K is a primary frequency regulation coefficient of the new energy power station; formula (11) is the mathematical model of the active power output by the inverters and has the same meaning as formula (4). In one embodiment, the optimal control sequences obtained by solving formula (5) are: u*(k)=[ΔPref*(k|k),ΔPref*(k+1|k), . . . , ΔPref*(k+Nc|k)] (12) Wherein, u*(k) is the optimal control sequence at the time k, Nca control domain length, ΔPref*(k+i|k),i=1, 2, . . . Ncis a control quantity at a time k+i of the inverters predicted at the time k, and ΔPref*(k|k) is a control quantity at the time k of the inverters. In practice, the control performance may be affected by the delay of a communication network, so a networked dynamic compensation mechanism for handling the delay of the communication network may be set based on predictive compensation. So, in Step13, the optimal control sequences at the different times are marked with time scales, the optimal control sequences are sent to executing devices of the power generation units at the corresponding times, and the executing devices of the power generation units receive the optimal control sequences and determine whether to store or not store the optimal control sequences according to the time scales. Specifically, on one embodiment, assume a maximum delay of the communication network is not greater than the control domain length Ncin formula (12), the optimal control sequences calculated in Step12are packed, the optimal control sequence packet is marked with a time scale through a time synchronization device and is then issued to the executing devices of the corresponding power generation units to be stored, and time scale comparison will be performed by the executing devices of the corresponding power generation units in the subsequent step. In one embodiment, if the time scales of the optimal control sequences received by the executing devices of the power generation units are less than or equal to the time scales of stored optimal control sequences stored in the executing devices, the received optimal control sequences will not be stored; otherwise, the received optimal control sequences will be stored. Step14, the executing devices of the power generation units determine the control quantities to be executed according to optimal control sequences received and stored in the executing devices and the time scales of the optimal control sequences. In one embodiment, if the time scale of the optimal control sequence received by the executing devices of the power generation units is identical with the time scale of the optimal control sequence stored in the executing devices, it is determined that the communication network is normal, and a first control quantity in the optimal control sequence stored in the executing devices is executed. In another embodiment, if time scale of the optimal control sequence received by the executing devices of the power generation units is not identical with the time scale of the optimal control sequence stored in the executing devices or the executing devices of the power generation units do not receive the optimal control sequence packet, it is determined that the communication network has a delay. So, in one example, if the optimal control sequence packet in Step13is not received at the present time k and assume the optimal control sequence packet stored in the executing device of the ithpower generation unit at this time is: ui*(ki)=[ΔPref,i*(ki|ki),ΔPref,i*(ki+1|ki), . . . , ΔPref,i*(ki+Nc|ki)] (13) A control quantity ΔPref,i*(k|ki) is performed, wherein kiis the time scale of the optimal control sequence packet stored in the executing device in the ithpower generation unit at the present time k. Assume the maximum delay of the communication network is not greater the control domain length Ncin formula (12), the control quantity ΔPref,i*(k|ki) exists when the communication network has a delay. hi another embodiment, if the time scale of the optimal control sequence packet received at the present time k is less than the time scale of the optimal control sequence packet stored in the executing devices and assume kiis the time scale of the optimal control sequence packet stored in the executing device in the ithpower generation unit at the present time k, a control quantity ΔPref,i*(k|ki) is performed. Assume the maximum delay of the communication network is not greater than the control domain length Ncin formula (12), the control quantity ΔPref,i*(k|ki) exists when the communication network has a delay. In another embodiment, if the time scale of the optimal control sequence packet received at the present time k is less than the time scale of the optimal control sequence packet stored in the executing devices and assume kris the time scale of the optimal control sequence packet received by in the executing device of the ithpower generation unit at the present time k, a control quantity ΔPref,i*(k|kr) is performed. Assume the maximum delay of the communication network is not greater than the control domain length Ncin formula (12), the control quantity ΔPref,i*(k|kr) when the communication network has a delay. Through the above steps, online allocation and predictive compensation of primary frequency regulation power of the new energy power station can be realized, but the primary frequency regulation effect will be affected when part of the units in the power station malfunction or the active power is limited. So, according to one embodiment, in Step12, a primary, frequency regulation power allocation result of the power generation units is determined according to the primary frequency regulation predictive values based on the pre-established inverter active power model, the primary frequency regulation power allocation result is adjusted according to a preset confidence function, and the optimal control sequences of the inverters of the power generation units at different times are determined according to the adjusted primary frequency regulation power allocation result. Specifically, in one embodiment, the confidence function may be expressed as: Ci(k+1)=1-ei(k)Pi*(k),i=1,2,…N(14) Wherein, Ci(k+1) is a confidence function at a time k+1, Pi*(k) is a power reference value at a time k of an ithpower generation unit, and ei(k)=|Pi(k)−Pi*(k)|δ is a power deviation function at the time k of the ithpower generation unit, and is defined as: ❘"\[LeftBracketingBar]"Pi(k)-Pi*(k)❘"\[RightBracketingBar]"δ={❘"\[LeftBracketingBar]"Pi(k)-Pi*(k)❘"\[RightBracketingBar]",❘"\[LeftBracketingBar]"Pi(k)-Pi*(k)❘"\[RightBracketingBar]">δ0,❘"\[LeftBracketingBar]"Pi(k)-Pi*(k)❘"\[RightBracketingBar]"<=δ(15) Wherein, δ is a set threshold for preventing a confidence decrease in presence of normal power fluctuations. According to the confidence function shown by formula (14), if the active power Pi(k) of the ithpower generation unit at the time k reaches a set value Pi*(k), the confidence Ci(k+1) of the ithpower generation unit at the time k+1 is 1; if the active power Pi(k) of the ithpower generation unit at the time k does not reach the set value Pi*(k), the confidence of the ithpower generation unit will be decreased, and primary frequency regulation power provided by the ithpower generation unit will also be decreased; if the active power of the ithpower generation unit reaches an upper limit or the power generation unit does not work due to a fault, Ci(k+1) is 0; and as can be known from formula (5), the weight value λi(k+1) of the ithpower generation unit at the time k+1 is 0, so the ithpower generation unit will not provide power for primary frequency regulation at this time. The networked control method for primary frequency regulation of a new energy power station provided by the embodiment in this specification can predict the frequency regulation potential of the new energy power station based on a short-term real-time prediction algorithm, thus solving the problem of poor primary frequency regulation, accuracy caused by uncertainties and fluctuations of the active power of new energy. In addition, during real-time power allocation of the new energy power station participating in primary frequency regulation, a corresponding optimization objective function is designed by taking into account the start-up cost of the power generation units of the new energy power station, so that the problems of low response speed, poor frequency regulation precision and network communication delay of primary frequency regulation in actual projects are solved, and it is ensured that the new energy power station participates in primary frequency regulation economically. Moreover, the output of each power generation unit of the new energy power station for primary frequency regulation is corrected by means of a dynamic weight coefficient based on a confidence function, so the problem of limited power regulation and faults of part of the power generation units of the new energy power station is effectively solved. Although the invention has been disclosed above with reference to preferred embodiments, these embodiments are not used to limit the invention. All technical solutions obtained based on equivalent substation or transformation should fall within the protection scope of the invention. | 18,252 |
11862983 | DRAWINGS—REFERENCE NUMERALS Ref. Numeral Description1Galvanic cell containment apparatus2Flow holes3Handles4Positive electrode5Negative electrode6Fluid containment reservoir plug7Fluid containment reservoir capture8Negative electrode lower edges9Lower bend region of negative electrode10Example electrolyte regions near positive and negative electrodes11Fluid containment reservoir12Alternate fluid containment reservoir13unused14Evacuated region near center of positive electrode15unused16Top edge of negative electrode17unused18unused19Negative electrode upper edges20Upper bend region of negative electrode21Earth22Antenna elevation means23Antenna in horizontal orientation24Antenna in vertical orientation25Antenna in coiled orientation27Earth ground location28unused29unused30Micro-chip, micro-circuits31Copper layer in micro-chip32Bond pad on micro-chip, plurality33Bond pad on micro-chip, plurality34Bond pad on micro-chip, plurality35Encapsulant over bond pad(s), electrically insulating36Bond wire, electrical interconnect37Copper layer, top surface, galvanic cell metal, Vp38Via, plurality, electrical interconnect between micro-chip layers39Via, plurality, electrical interconnect between micro-chip layers40Silicon dioxide insulation between micro-chip layers41Diffusions in substrate or epitaxial layer of semiconductor material42Diffusions in substrate or epitaxial layer of semiconductor material43Diffusions in substrate or epitaxial layer of semiconductor material44Substrate or epitaxial layer of semiconductor material45Encapsulant substantially around semiconductor material46Transistor gate, one of a plurality of transistors47Substrate or epitaxial layer of semiconductor material48Surface of contact between first and second micro-chips, stacked49Encapsulant substantially around stacked micro-chip assembly50Metallic sheet, galvanic metal51Interconnect between Metallic sheet (50) and substrate or epi-layer (47) DRAWINGS—REFERENCE DESIGNATORS Ref. Designator DescriptionAnt Antenna, electrically conductive wiringA Wave RectifierB Wave Rectifier, alternate embodimentC1Polarized capacitor, charge storage elementC2Coupling capacitor, AC coupled wave energyC3Coupling capacitor, AC coupled wave energyC4Capacitor, charge storageC5Capacitor, resonance frequency tuningC6, C7Capacitor, charge storageCN Common node, wave rectifier B arrayD1, D2Diode, light emissionD3Diode, rectificationD4Diode, blocking current from flowing back into the rectifier arrayDN Diode, light emission, pluralityDblock Diode, blocking current from flowing back into pulse generator/oscillatorE Earth ground nodeL1Inductor, coupled with L2L2Inductor, coupled with L1L3, L4, L53 Inductors, Tri-filar wound, coupledLamp Light emitter, gasLOAD Electrical circuit, powered by VoutN NegativeP PositiveU Antenna rectifier array and energy storage circuitU1Opto-couplerU2Voltage Regulator, power management circuitU3Micro-circuits, integrated circuitsUN Plurality of circuit blocksVcell Galvanic cell batteryVp Positive electrode, Galvanic cell batteryVn Negative electrode, Galvanic cell batteryVout Pulse generator output voltage, drives load circuitsVrechargeable Battery, rechargeableVst Voltage, stored, deliverable to a load circuitX An arrayed plurality of wave rectifiers, A or BR1Current limiting resistor, Vcell loadingR2Current setting resistor, U1opto-couplerR3Current setting resistor, Q1pulse generator/oscillatorR4Current limiting resistor, battery chargingR5Current limiting resistor, lamp illuminationR6Current limiting resistor, speaker driveR7Current limiting resistor, Q1base driveRp Photo (light) sensitive resistorSG1, SG2Switch, gas breakdownSW1Switch to disable Rp operationSW2Switch to disable U1operationSW3Switch to disable Q1operationSW4Switch to disable Rp operationSW5Switch to disable current to the LoadSW6Switch to disconnect Vcell from circuitsQ1NPN Transistor, pulse generator/oscillatorY Load circuit, may emit light or soundZin Input node for the LoadZspeaker Speaker impedance (speaker generates sound when driven) DETAILED DESCRIPTION The following detailed descriptions provide substantive instruction regarding how to make and use the numerous embodiments of the present invention. However, the invention may be practiced without some of these specific details.FIGS.1through5depict a plurality of interchangeable features and components. The embodiments and features may be combined or reduced, yielding a plurality of combinations and forms, some simple, and some complex. Embodiments of FIG.1 FIG.1adepicts a side view of a galvanic cell containment vessel (Ref. Numeral1), preferably made from a sturdy and substantially electrically insulating material such as High Density Poly-Ethelyene (HDPE) or similar plastic compounds, and preferably 6 to 24 inches in diameter and 6 to 24 inches in depth. The containment vessel may be visibly transparent, or opaque. It may also be made of glass, cardboard, or paper. Reference numeral3depicts general carry handle locations for picking up, placing, or removing, the containment vessel. Reference numeral2depicts a plurality of lower exit flow hole locations at the bottom of the containment vessel through which fluid, electrolyte, and soil may drain. While the exit flow holes may be located anywhere near the bottom of the device, they have preferably been dispersed in a symmetrical arrangement in the following diagrams, but substantial symmetry is not required in order for exit flow holes to function. Symmetry is aesthetically pleasing and presents uniform exit flow function. In alternate embodiments, a plurality of exit flow holes may be placed in asymmetrical arrangements. Exit flow holes may also be located along the lower sides of the containment vessel in symmetrical or asymmetrical arrangements. FIG.1bdepicts a top view of a general containment vessel (1), once again showing approximate locations for carry handles (3) near the sides, and a general plurality of exit flow holes (2) near the bottom of the containment vessel. In an alternate embodiment, the carry handles may be positioned substantially lower on the containment vessel. FIG.1cdepicts a side view of a substantially spiral-shaped coil, approximately 1 inch to 6 feet in diameter, but preferably about 12 inches in diameter. In a preferred embodiment, the spiral-shaped coil is the positive electrode for a galvanic cell and comprised substantially of copper. The spiral rings of the coil are spaced about % inch to 3 inches apart, but the spacing does not need to be substantially symmetrical or substantially uniform from spiral to spiral. In a preferred embodiment, the spiral ring spacing as approximately 1 inch between spirals. For handling ease and lower cost, it may be preferable to make the spiral coil that is approximately 6 inches to 18 inches in diameter. The spiral coil is preferably formed from approximately 5 to 20 feet in length of substantially hollow copper tubing and possessing substantial exposed surface area both inside and out of the hollow tubing. In an alternate embodiment, the spiral coil may also be formed using solid copper wire or copper mesh. The hollow copper tubing may possess an inside diameter of approximately 1/32 inch to 2 inches, and the thickness of the copper may be approximately 1/32 inch to ½ inch. Preferably the hollow tubing is about 10 feet in length, and has an inside diameter of approximately H inch and a thickness of about 1/16 inch. This may yield a substantially compact and affordable spiral coil embodiment. FIG.1ddepicts a side view of a general galvanic cell system including a general containment vessel (1). Reference numeral5depicts a metallic sheet, preferably the negative electrode. It is preferably comprised substantially of zinc. In an alternate embodiment the metallic sheet may be iron and substantially zinc plated for galvanic function. When formed, the metallic sheet substantially surrounds the spiral coil, but does not contact the spiral coil. The metallic sheet is preferably the negative electrode, but in an alternate embodiment of the galvanic cell, the polarities of the spiral coil and the metallic sheet surrounding the coil may be switched. The general position of the metallic sheet surrounding the spiral coil is depicted inFIG.1e. The metallic sheet may reside about ¼ inch to 12 inches from the spiral electrode. Preferably the metallic sheet is distanced about 1 inch from the spiral coil rings. The spiral coil preferably forms the positive electrode of the galvanic cell, and the metallic sheet surrounding the spiral coil preferably forms the negative electrode. Since the containment vessel is preferably made of HDPE or another form of electrically insulating plastic, the containment vessel is an electrical insulator and does not substantially affect the electrical operation of the electrodes. However, in an alternate embodiment the containment vessel may be substantially comprised of glass, metal, semi-conductor material, carbon, cloth, cardboard, paper, or similar. For ease of assembly, and replacement, it may be preferable that the metallic sheet either contact the containment vessel or reside generally near it as shown. In an alternate embodiment there may be a substantial spacing between the containment vessel and the metallic sheet. This may be necessary1fthe containment vessel is comprised of metal. To utilize the galvanic cell system, the containment vessel is filled with an electrolyte, preferably moistened-soil (reference numeral10) thereby holding the spiral coil near the center region of the containment vessel and also keeping the spiral coil from contacting the metallic sheet surrounding it. It is not necessary that the spiral coil and metallic sheet be completely covered in moistened soil or electrolyte, but it is preferable to cover the two electrodes substantially and as much as is convenient for assembly and also making external electrical connections to the electrodes. Electrical connections to the electrodes may be made by welding, soldering, melting, clip leads, clamps, or similar. The entire galvanic cell system may be covered in soil. It may be substantially buried below ground in whole or in part, or it may be situated fully above ground on a patio, in a yard, on an elevated table, or similar. It is preferable that moistened soil (10) not contain substantial amounts of clay or rocks, as the clay and rocks may reduce the quality of the galvanic cell reactions. While it is preferable to use water moistened soil, wet sand or sea water may also be utilized instead of moistened soil in alternate embodiments. Moistening soil (10) with water initiates electro-chemical reactions between the metals and the damp soil (electrolyte), and over about 1 to 48 hours the galvanic cell will increase in electrical output capability from the electrodes. When using untarnished and new metals, it may be preferable to wait at least 12 hours before using the galvanic cell system. This will yield the largest energy output from the cell. It may be convenient and desirable to use the present invention outdoors where rain and other natural water sources exist. In a preferred embodiment, the fluid utilized in the galvanic cell is environmentally available water. As the containment vessel fills with water over time (due to rain water or other irrigating sources), a plurality of exit flow holes (ref numeral2) near the bottom of the containment vessel serve to drain the galvanic cell system so that it does not become substantially over-saturated with fluid and degrade the galvanic cell electrolyte. The metals in the galvanic cell will accordingly corrode and degrade over many days and months, with the negative electrode sheeting (zinc) suffering a much more catastrophic corrosion and depletion, especially1fsubstantially immersed in water, reactive liquids, or substantial moisture. Zinc is a much more sacrificial metal than copper. For this reason, it is desirable that the zinc sheet or zinc plating have a thickness of about 1/128 inch to 1 inch. Preferably a zinc thickness of greater than 1/32 inch is desirable in order to increase the longevity of the galvanic cell. As the electrical current output and power output from the galvanic cell system wanes over time, the metal components and electrolyte may be replaced or supplemented. The components may be re-used until they are substantially corroded or eaten away or structurally compromised to a point where they are ineffective. In circumstances where lowest cost is desired, thinner metal thicknesses and electrodes may be used. The surface areas of the metals are largely where the electro-chemical reactions take place. Plated electrodes may be useful to reduce cost, but life expectancy may be less as the plated metal disappears from the electrodes and reveals the core material or core metal (such as iron). One may select metal thicknesses and metal platings based upon cost and complexity requirements for the galvanic cell system. It is preferable to use substantially uniform metal components for longevity and simplicity of the galvanic cell system. For example, substantially uniform zinc sheeting, and substantially uniform copper tubing. Metals other than copper and zinc may be alternatively used inasmuch as the galvanic cell voltage generated is usable for the end application. FIG.1eis a general top view for the galvanic cell system depicted inFIG.1d FIG.1fis an alternative embodiment ofFIG.1e. Reference numeral14denotes a general location for a substantially voided region near the center of the spiral electrode. This substantially voided region may be useful to visually observe or monitor fluid or electrolyte level within the containment vessel, or useful to hold auxiliary electrical circuitry and associated connections, or to hold secondary galvanic cells or micro-chips or sensors, or to reduce the amount of soil (electrolyte) required to fill the vessel. This substantially voided region may be useful in any embodiments of the present invention. The voided region may lower the cost, weight, complexity, improve visibility into the fluid and water saturation levels, and make a galvanic cell system more compact with improved utility. In a preferred embodiment, this substantially voided region is substantially cylindrical in shape and comprised of a visibly clear plastic, clear HDPE, or glass. It may also be comprised of cardboard, paper, or similar. The cylinder may be either closed or open on either end. The diameter of the cylinder or tube may be approximately 1 inch up to the diameter (size) of the coil. The cylinder may or may not contact the spiral coil electrode. Preferably a clear plastic cylinder is utilized and approximately 3 inches in diameter and spaced approximately 1 inch from the spiral coil. The cylinder does not need to be visibly clear, but it is preferable in order to view the galvanic cell soil and fluid levels. In this way, the cylinder may or may not fill with water, soil, or electrolyte, depending upon whether the bottom of the cylinder is closed-off or open. While it is preferable that the lower end of the cylinder be closed off, either cylinder construction or configuration may work. In an alternate embodiment the bottom of the cylinder possesses holes in order to let substantial fluid pass into the cylinder but not soil. The cylinder may also serve to electrically isolate any housed electronics, secondary galvanic cell systems within the cylinder, or lighting systems placed within the cylindrical tube. The preferred configuration depends upon the galvanic system constraints and requirements. FIG.1gdepicts a side view of an alternative embodiment with a removable fluid collection apparatus (reference numeral11) at the bottom of the containment vessel. In a preferred embodiment the containment vessel of prior embodiments may be placed on top of this fluid collection apparatus. Fluid, electrolyte, and soil (10) may collect in region7of the fluid collection apparatus. Reference numeral6depicts a general and removable plug location which may be utilized as a pathway for fluid, soil, and electrolyte, or serve as a general out-flow port when fluid levels reach the plug elevation, as the collection apparatus (11) fills over time. For example, this may occur after a rain storm, or general fluid-filling of the galvanic cell system. This embodiment may have utility when using the galvanic cell above ground, or on a substantially flat surface such as a patio area. The embodiment may also be useful when burying the galvanic cell system in whole or in part, as the upper portion of the containment vessel may be lifted off of the fluid collection apparatus. The fluid collection apparatus (11) may be sized sufficiently and effectively large enough to accommodate the exiting of fluid expected to over-flow from the galvanic cell system. In a preferred embodiment the diameter of the fluid collection apparatus is approximately the same as the galvanic cell containment vessel base. In an alternate embodiment it is 1 to 10 times the diameter of the containment vessel base. In another alternate embodiment the fluid collection apparatus is made from visibly clear glass or transparent plastic so that fluid levels within it may be observed. FIG.1his another alternative embodiment. The electrode sheeting surrounding the spiral coil now extends substantially underneath the spiral coil. In a preferred embodiment, the metallic sheeting extends at least 1 inch beyond the spiral coil. In another embodiment the sheeting extends to substantially close-off the bottom region and leave only a small gap near the center region of approximately 1/16 inch in diameter. FIG.1idepicts an embodiment wherein the electrode sheet extends both above and below the spiral coil. The extents of the sheet may be similar toFIG.1h. This embodiment may be useful when pursuing maximum electrical resonance of the structure and maximum electrical current output from the galvanic cell system. Maximum resonance with the load circuit may be achieved when the negative electrode (zinc) substantially encases the positive electrode spiral (copper) at both top and bottom regions. The pulsed electrical output (voltage spikes) from the galvanic cell up-converter circuits (Vout) may increase in magnitude as the negative electrode sheet substantially extends both over and under the spiral electrode. In order to achieve best operation and resonance from various galvanic cell embodiments, some experimentation may be required in order to find optimal configuration and performance for the galvanic cell system and its inter-changeable circuits and components. FIG.1jdepicts an alternate embodiment possessing a substantially conical shaped containment vessel, a substantially conical shaped spiral coil (preferably positive electrode), and substantially conical metallic sheet (preferably negative electrode) surrounding the spiral coil. In an alternate embodiment the positive a negative electrode materials and may be reversed. TheFIG.1kdepicts a general removable overflow apparatus at the bottom of the containment vessel. The electrode sheet extends substantially underneath the conical spiral coil. In the embodiment ofFIG.1lthe electrode sheet extends both above and below the conical spiral coil. In an alternate embodiment the sheet may extend only over the upper portion of the spiral coil. However, it is preferable to extend the sheet substantially over both ends of the spiral coil. The embodiment ofFIG.1mdepicts a general top view for overflow containment regions. The diameters displayed may be varied without departing from the scope of the present invention. A removable plug (ref. numeral6) is depicted, and a containment ring (ref. numeral7) resides inside the overflow containment apparatus (11). General handles for carrying and removal (3) are also depicted. In a preferred embodiment, the galvanic cell system may be placed on top of this overflow containment apparatus. In alternate embodiments, the overflow containment apparatus (11) is either temporarily affixed, or permanently affixed to the galvanic cell containment vessel. The diameter of the overflow containment apparatus may be substantially larger or smaller in diameter than the containment vessel. A larger diameter may serve to better stabilize the galvanic cell system and containment apparatus, and also hold increased fluid overflow. In alternate embodiments the overflow containment apparatus may be substantially comprised of a plastic, such as HDPE, or glass, and may be transparent enough to allow viewing of fluid level within it. This can assist in optimizing the life and operation of the cell by keeping the soil (electrolyte) moist but not over-saturated. FIG.1ndetails an alternate embodiment possessing a simplified removable overflow containment apparatus (12) at the bottom of the device. This embodiment may also possess the variables of the prior embodiment. To simplify the embodiment, there is no drain plug (6). The electrode sheet may also extend substantially beneath the conical spiral coil. In the embodiment ofFIG.1o, the electrode sheet extends substantially both above and below the conical spiral coil. In alternate embodiments the sheet may extend either above, or below, as described in earlier embodiments. The embodiment ofFIG.1pdepicts a top view for a simplified overflow containment apparatus and approximate diameters for implementation. The larger containment region (ref. numeral7) is depicted inside the overflow containment apparatus (12). General handles for carrying and removal (3) are also depicted. Components of the variousFIG.1embodiments shown and described may be mixed and matched without departing from the scope of the present invention. Embodiments of FIG.2 The embodiments shown inFIGS.2a,2b, and2c, depict a general design and method for producing a formed electrode from a metallic sheet (preferably zinc) which generally fits within a containment vessel, or embodiments ofFIGS.1athrough1i. The upper edge of the metallic sheet is denoted as reference numeral16, and possesses a plurality of flaps depicted on the bottom (reference numeral8). In alternate embodiments, the number of flaps may be between 1 and a plurality. FIG.2bdepicts a general side view cut-away (center cut) of the embodiment after forming into cylinder shape. The upper edge of the metallic sheet is denoted by reference numeral16, and the side edge of the formed sheet denoted by reference numeral5. The sheet is formed into a general cylinder shape. The metallic sheet may possess a plurality of flaps which are preferably folded at approximately 90 degrees in order to traverse underneath the spiral center coil ofFIGS.1athrough1i. This folded or bent region is denoted by reference numeral9and may be varied greatly, such as any angle between 0 degrees (unfolded) through 180 degrees (folded back against the cylinder wall). The metallic sheet does not need to completely close-off the bottom of the cylinder formation, and in a preferred embodiment a small gap in the center of about ½ inch diameter allows effective drainage. This can be seen as reference numeral8on the plurality of flaps. This functional gap allows fluid, electrolyte, or soil to pass out the bottom of the device. Without a small gap, fluid, electrolyte, and soil may not drain out the bottom of the containment vessel and standing water or fluid may collect and degrade the performance and longevity of the galvanic cell system. FIG.2cis a top view showing the upper edge of the sheet (16) and bendable flaps at the bottom (ref. numerals9and8). The embodiment shown inFIGS.2d,2e, and2f, depicts an alternate design and method for a formed metallic sheet (preferably zinc) generally fitting a containment vessel, such as depicted in embodiments ofFIGS.1athrough1i. This metallic sheet contains a plurality of flaps both on the top and bottom (reference numerals8,9,20and21), and is formed and bent in a similar fashion and form, with similar extent variances and flexibility. FIG.2edepicts a cut-away side view (center cut) after forming. The upper flaps of the metallic sheet are denoted by reference numerals20and21, and the side edge of the sheet is denoted by reference numeral5. The metallic sheet is generally formed into a cyclinder shape. The metallic sheet possesses flaps (both above and below the spiral coil) which are preferably bent at approximately 90 degrees to traverse both underneath and above the spiral center coil ofFIGS.1athrough1i. These bend regions are denoted by reference numerals9and20and the bend range may be between 0 degrees and 180 degrees similar to the previous embodiment. The metallic sheet may or may not completely close off the bottom or the top of the device. This can be seen as reference numerals8and21on the plurality of flaps. Preferably there remains a functional gap of about ¼ inch to 3 inches allowing fluid, electrolyte, and soil to pass out the bottom of the device, and also a ¼ inch to 3 inch gap at the top providing access to the galvanic cell system through the top region of the containment vessel. It is not necessary that the top and bottom gaps be the same extent or coverage or bend angle. Without a small gap at the bottom of the device, fluid, electrolyte, and soil may not drain out the bottom of the containment vessel and thereby prevent standing water and over-saturation of the cell. The flaps above and below the spiral coil may also help the galvanic cell system achieve more substantial resonance and electrical current output. In another embodiment, it is preferable that the gap be approximately 1 inch diameter at both the top and bottom of the device, providing both access to the top of the galvanic cell system, and drain relief at the bottom. The gap sizes are variable, and depend upon the requirements for the galvanic cell system. They may be different diameters at top and bottom. FIG.2fis a general top view depicting approximately 90 degree bent flaps at both the lower and upper regions (ref. numerals8,9,20and21). Embodiments of FIG.3 FIG.3apresents a general schematic for a multi-featured voltage conversion circuit. In a preferred embodiment, the circuit is attached to a galvanic cell (Vcell) and the circuit up-converts the galvanic cell's low voltage DC to a pulsed AC output of between tens and hundreds of volts. This is desirable since the voltage output of the galvanic cell is generally less than 1 volt DC. It is therefore desirable to up-convert the voltage potential of the galvanic cell in order to do electrical work such as illuminating lights, sounding a speaker, powering a useful circuit block, powering miscellaneous circuits or a micro-chip assembly, charging a battery, transmitting communications, etc. In a preferred embodiment,FIG.3apossesses a light sensitive resistor (Rp) to enable or disable electrical conversion from the galvanic cell. The light sensitive resistor may be activated by sunlight or a light source such as an LED, laser, bulb, gas, or similar light source. The resistance of photo-resistor Rp drops proportionally when light impinges it, thereby causing the pulsed AC output of the circuit to commence when substantial darkness occurs. The preferred operation of the circuit ofFIG.3ais also a function of the switch positions SW1and SW2, and as follows:SW1SW2Voutopen open OFFclosed open OFFopen closed ON (pulsing AC spikes)closed closed ON in substantial darkness (pulsing AC spikes) The switch positions of SW1and SW2allow turning OFF the galvanic cell draw and up-conversion circuits. In a preferred embodiment, resistor R1is approximately 10 ohms but R1may also be between 0 and 1000 ohms in alternate embodiments. Resistor R1allows the circuit to be operated with a wider range of Vcell or general battery voltage levels, so1fthe up-converter circuit ofFIG.3adoes not output pulsed AC spikes, then adjusting the value of R1up or down may help the oscillations commence.FIG.3amay be used with galvanic cell batteries or other types of batteries such as alkaline, nickel cadmium, lead acid, or similar. As such, the circuit may be utilized with or without a galvanic cell, such as with a small 1.5V AA or AAA sized cell. In a preferred embodimentFIG.3ais powered with a galvanic cell. In an alternate embodimentFIG.3ais utilized with Vcell provided by a one or a plurality of sealed batteries or alkaline batteries or rechargeable batteries. Resistor R2sets the bias current through the photo-diode in U1(opto-coupler). R2may be 0 ohms to 100K ohms depending upon Vcell applied to the circuit. In preferred embodiment, R2is approximately 100 ohms but may need adjustment to maintain proper bias of the photo-diode in U1. When light impinges the photo-resistor Rp, the photo-resistor shunts electrical current around the photo-diode in U1, and stops bias of U1thereby disabling the pulsed AC output of the circuit (Vout). This may have utility when the sun comes up, and when the sun sets. Switch SW1can disable the photo-resistor Rp when SW1is opened. Switch SW2can disable the whole circuit when SW2is opened. Coupled inductors L1and L2work in conjunction with transistor Q1to create an oscillator and generate substantial periodic voltage spikes on Vout. L1and L2may be approximately 1 milli-Henry to 1000 milli-Henry in inductance, but preferably about 10 mH to 30 mH. L1and L2are preferably the same type of inductor and substantially same value. It may be preferable that L1and L2are largely unshielded so that they may substantially couple magnetically through the air into one another. Transistor Q1is preferably an NPN bipolar transistor. In alternate embodiments Q1may be selected from the group consisting of 2N2222, 2N3055, 2N3904, 2N5210, or similar in specification and gain. It may be necessary to optimize transistor selection and inductor sizing for largest AC spikes on Vout. Preferably, the oscillating pulse train on Vout should be between 1 KHz to 50 KHz and the voltage spikes on Vout of 50 volts or greater magnitude. This allows operation of a great many circuits and functions (depicted by the circuit block labeled LOAD). As such, Vout is connected to Zin of the LOAD circuit depicted, and also to Vn of the battery (Vcell) powering the circuit. Accordingly, the LOAD circuit must be designed to accept and utilize the spiked AC output on Vout. In an alternate embodiment, a plurality ofFIG.3acircuits may be connected to one or more galvanic cells. In other words, a single galvanic cell may drive a plurality ofFIG.3acircuits. The number ofFIG.3acircuits which may be powered by the galvanic battery (Vcell) are empirically determined. For example, when powering lights, the lights will dim when the loading is too great. In an alternate embodiment, theFIG.3aschematic is simplified wherein R1=0 and both SW1and SW2are shorted, thereby effectively removing R1, SW1, and SW2from theFIG.3acircuit, and simplifying it. In yet another alternate embodiment, U1may comprise an LED shining substantially onto a photo-resistor. As such, U1may be effectively fabricated from a plurality of photo-responsive transistors, LED's, resistors, and similar devices. Depending upon performance needs and cost, one skilled in the art may opt for various alternate embodiments. FIG.3bis an alternate embodiment and operates similarly toFIG.3a. R1, L1, L2, and Q1, ofFIG.3bwork in similar fashions. Switch SW3will disable Vout up-conversion when SW3is opened. Switch SW4will disable light controlled operation and control of photo-resistor Rp. Resistor R3is selected in order to optimize operation of transistor Q1base drive and also perform voltage division with resistor Rp. In a preferred embodiment, resistor R3is approximately 0 ohms to 100K ohms. When resistor Rp is impinged with light from the sun or other desired source, the base of transistor Q1becomes sufficiently un-biased so as to stop oscillation in the Q1, L1, and L2circuit. In yet another alternate embodiment, switches SW3and SW4are shorted and may be removed from the circuit. This simplification can lower the cost of implementation.FIG.3bdepicts a LOAD circuit that in similar fashion and form toFIG.3a, may be attach to Vout. As before, reasonable optimization of circuit resonance and oscillation parameters may be necessary for a particular galvanic cell system.SW3SW4Voutopen open OFFclosed open ON (pulsing AC spikes)open closed OFFclosed closed ON in substantial darkness (pulsing AC spikes) FIG.3cdepicts an approximate physical arrangement of two radial leaded inductors (L1and L2) which may provide preferred and substantial coupling of magnetic fields between L1and12, thereby supporting up-conversion oscillation and substantial voltage spikes on Vout. In a preferred embodiment, radial leaded inductors L1and L2are placed substantially adjacent to one another as depicted. In alternate embodiments, the two inductors L1and L2may be spaced up to an inch a part and still couple enough magnetically to bring oscillation, albeit less. As such, substantial circuit oscillation is usually best achieved when radial leaded inductors L1and L2are placed substantially adjacent one another as depicted inFIG.3c. This positioning of radial leaded L1and L2applies to the circuits in bothFIGS.3aand3b. L1and L2are preferably unshielded radial leaded inductors and between 10 mH and 30 mH in value, but they may be substantially larger or substantially smaller, and of different individual inductances as long as effective oscillation ensues. The values of L1and L2may be empirically selected in order to create largest AC voltage spikes at circuit node Vout. In an alternate embodiment, L1and L2are comprised of general coils of magnet wire wherein the spiral geometries of the two coils are substantially coupled magnetically and the two coils are arranged between 0 to 180 degrees in Y-axis orientation with one another. Placement is effective when oscillation ensues. Preferably coils L1and L2reside in substantially the same orientation. One skilled in the art will appreciate orientations for coupling fields between inductive coils and also empirical adjustments for creating resonance and oscillation in the circuits ofFIGS.3aand3b. FIG.3dpresents a general schematic for a high frequency oscillator circuit. In a preferred embodiment, the circuit is attached to a galvanic cell (Vcell) and the circuit converts the galvanic cell's low voltage DC to a oscillating AC output frequency of between 10 KHz and 100 MHz on Vout. The oscillation may or may not be substantially sinusoidal, and in some embodiments the oscillation may resemble a smoothed saw-tooth wave. Resistor R1serves to limit the current from the battery source Vcell, and also to fine tune circuit oscillation. R1is preferably 0 ohms, but may need to be increased to between 1 ohm and 100 ohms for oscillation to ensue. The value of R1may need to be adjusted versus Vcell battery type. For example, a 1.5V alkaline AA or rechargeable AAA battery may require about 10-20 ohms for R1. A galvanic cell may require 0 ohms for R1. Inductors L3, L4, and L5work in conjunction with transistor Q1to form an oscillator. Q1may be a 2N3055, 2N2222, 2N3904, 2N5210, or similar high gain NPN transistor. In a preferred embodiment, inductors L3, L4, and L5are comprised of a flat-wound tri-filar coil. The flat-wound coil may be fabricated any number of ways, but preferably from insulated 3-conductor Romex wire (12/3 14/3, 16/3, etc.) that is commonly utilized for 117 VAC home wiring, or 117 VAC outdoor wiring. The gauge wire may be between 10 gauge and 20 gauge, but is preferably 12-16 gauge, solid copper wire. A length of Romex of between 25 feet and 200 feet may be used, but 100 feet is preferable. Once the length of Romex has been wound into a flat-wound spiral, looking much like a pancake, the 3 conductors represent inductors L3, L4, and L5, in order. R7represents a current limiting resistor for adjusting the driving of the base of transistor Q1, and may be between 0 ohms and 10K ohms. R7is preferably 0 ohms, but may be adjusted upward1fmore sinusoidal wave shape is desired. R1is adjusted upwards from 0 ohms until oscillation ensues on Vout. Oscillation on Vout may be between 50 KHz-10 MHz, and as such, these frequencies may be used for communications, signal transmissions, notifications, rodent or pest deterrence, dog repulsion, either in the earth or in the air. The oscillations on Vout may also be modulated or chopped by LOAD circuits using common methods. As with the prior embodiments, the circuit ofFIG.3dmay also be modified to include a switch (SW6) in order to turn ON or OFF the circuit operation. For example, a single-pole single-throw switch (SW6), may be placed in series with R1in order to enable or disable current from Vcell into the circuit. Inductors L3, L4, and L5may also be formed from wire other than insulated solid copper wire in Romex, such stranded wire, or tri-filar stranded and insulated copper wire 8 gauge to 40 gauge. Magnet wire may also be used. Romex is preferable due to its low cost, inherent bi-filar or tri-filar configurations, ease of winding into a flat-wound coil, and ability to be easily positioned as an antenna or emitter in the air or in the earth. Preferably the flat-wound coil of Romex is approximately 1-2 feet in diameter. It may be buried, or placed above ground. It may be used to ward off rodents in the ground, repulse dogs, send communication transmissions, alerts, or modulated notifications or communications to others via radio wave transmission. In an alternate embodiment, the AC oscillations may be rectified and converted to DC for similar uses and transformations as earlier embodiments in this specification. One skilled in the art will appreciate the utility and variations. FIG.3erepresents a LOAD circuit which may be attached to theFIG.3a,3b, or3dcircuits. Vout is connected to the Zin node of the LOAD circuit. Vn of the LOAD circuit is connected to the negative electrode of the galvanic cell or battery (Vcell). When switch SW5of the LOAD circuit is closed, the voltage driver output (Vout) ofFIG.3a,3b, or3d, pulses current through the parallel array of diodes which are labeled D1, D2, through DN. DN represents a plurality of diodes. In one embodiment, a plurality of diodes may be Light Emitting Diodes (LED's). As such, when large voltage excursions appear on Vout, this forward biases and illuminates the LED's in a quick burst. Since repetitive bursts may occur at a rate of approximately 1 KHz to 50 KHz and beyond, the individual pulse train is not observable to the human eye. The light emitted appears to be continuous. This LOAD circuit is well suited for using the same type of diode in plurality. For example,1fall diodes are white LED's then this circuit will work well. Laser diodes may also be utilized in another embodiment. Using diodes with substantially different forward bias voltages may be problematic here since the diodes with substantially higher forward bias voltage may not get appreciably biased. The following embodiment ofFIG.3fresolves this shortcoming. FIG.3fpresents an alternative embodiment ofFIG.3ewherein the plurality of diodes D1, D2, through DN, may be stacked in series instead of parallel. The overall affect of voltage excursions on Vout through the diode circuit is the same. A voltage spike through the series diodes creates a burst of light1fthe diodes are LED's. In an alternate embodiment, none, some, or all of the diodes may be LED's, or different color LED's. Laser diodes may also be used in another embodiment. This circuit may be useful when diodes with substantially differing forward bias voltages are used, such as when utilizing multiple colors of LED's, or when driving infrared or ultraviolet LED's at the same time as other color LED's. All colors of LED's may be driven at once without their different forward bias voltages substantially affecting the others. This may be useful for Christmas lights, full spectrum lighting, or colorful light decorations. Ultraviolet LED's may also be useful to kill off micro organisms. Infrared LED's may be useful for creating invisible light beams for communications, trip sensors, or general IR illuminations of organisms or objects. The forward bias voltages of all LED's must not exceed the magnitude of the Vout voltage peak. If so, the LED's may not illuminate substantially, or at all. FIG.3gdepicts an alternate embodiment where the LOAD circuit is comprised of a speaker or plurality of speakers. The speakers may be of ultra-sonic type, or audio type. Since the Vout voltage pulse train from the driver circuits ofFIGS.3a,3b, and3d, may be varied, it is possible to create sonic bursts at between approximately 100 Hz and 50 KHz. Ultra-sonic sound may be useful to ward off pests, or rodents, or dogs. Alternatively, audible sounds may be useful when an infrared light beam has been crossed or broken. As such, multi-toned galvanic cell systems may be utilized to make outdoor motion detection systems. It is possible to combine in series or parallel these numerous LOAD circuit embodiments. It is possible to attach a plurality ofFIGS.3a,3b, and3d, driver circuits to a single galvanic cell or plurality of batteries such as alkaline or nickel cadmium or lead acid. The variations are numerous. FIG.3hdepicts a LOAD circuit which may be useful to refill a rechargeable auxiliary battery. For example, one might trickle charge a 12V car battery over many days using the high voltage spikes from Vout. When switch SW5of the load circuit is closed, the Vout voltage spikes from the driver circuit will pulse current through the blocking diode (Dblock) and through current limiting resistor R4, and into the rechargeable battery. The blocking diode (Dblock) prevents the rechargeable battery from pushing current back into the driver circuit Vout node. In this way, the low voltage DC of the galvanic cell may be up-converted via the Vout voltage spikes of the driver circuit and charge a battery. This circuit may charge a battery of any voltage such as a 1.2V nickel cadmium cell, or a 36V cell, or greater. As long as the voltage spikes on Vout exceed the rechargeable battery voltage then electrical current will flow into the rechargeable battery and charge it, albeit slowly. Once the battery is charged to the appropriate voltage level, it should be removed from the charging circuit. Since the voltage spikes from the driver circuit (Vout) can be in the realm of volts to over a hundred volts, multiple 12V batteries could be stacked in series and charged. Possibilities for the system are again numerous. FIG.3idisplays an embodiment where a gas bulb or gas lamp may be excited (illuminated) by the Vout voltage pulses of the driver circuits inFIGS.3a,3b, and3d. When switch SW5is closed, the voltage pulses on Vout are applied to the gas bulb or gas lamp. A gas such as neon may be useful here, since it breaks down near 80 volts and emits light. Embodiments of FIG.4 FIG.4adepicts an antenna rectifier circuit (A), and an array of them (X) interconnected. To operate the circuit, array (X) is connected to an antenna. The received electricity from the antenna is coupled through capacitor C2to the rectification diodes (D3) and stored across capacitors labeled C1. C2may be a ceramic capacitor of value 0.01 uF to 1 uF, but preferably about 0.1 uF. Alternatively C1may be mylar, poly-propalene, mica, polystyrene, or similar. C1may be an electrolytic capacitor of value between 0.1 uF and 10000 uF, but preferably 10 uF to 100 uF. C1is preferably placed in the circuit in reverse polarity (as shown) to the C1capacitor case marking. The array (X) of rectifiers serves to raise the stored DC voltage since the plurality of C1capacitors of array X are stacked in series. In a preferred embodiment, capacitor C1is electrolytic and installed in circuit A in reverse polarity. This reverse installation is not obvious, and energy (voltage) is stored on the electrolytic capacitor in a polarity opposite to the marking on the capacitor. The amount of voltage stored across capacitor C1is a function of the signal amplitude received and rectified from the antenna. This is why stacking a plurality circuit block A is necessary in order to achieve hundreds of volts DC stored potential on array X. It is preferable to stack circuit A in an array of between 10 to 1000 elements in order to create antenna rectifier block X. If the antenna receives substantial energy upon it, then a smaller array of circuit A may suffice. Illuminating a neon bulb can require approximately 80 volts, so1fthis is the task at hand, then the array (X) will need to be sufficiently numerous in order to create a stored voltage great enough to breakdown the neon gas. It may take array X a plurality of seconds in order to charge up and achieve this magnitude of stored voltage. If the circuit does not appear to be charging sufficiently, it may be necessary to disconnect all loading upon array X while the antenna is charging the array. For example, a digital multi-meter or test probe may problematic and load the array X circuit thereby inhibiting its proper operation and rectification. If array X does not achieve tens or hundreds of volts stored on the C1capacitors, then one may need to either change the antenna orientation or height, or add more antenna element A units to array X, or momentarily remove multi-meter test probes or test circuits loading array X. FIG.4brepresents an alternate embodiment. The coupling capacitor C3leading from the antenna may be a ceramic capacitor of value 0.01 uF to 100 uF. Preferably it is about 1 uF to 10 uF. As with the prior embodiment ofFIG.4a, C3may be poly-propalene, polystyrene, mica, mylar, or similar. A plurality of circuit block B are interconnected to achieve the desired stored DC voltage potential on capacitors C1in array X. FIG.4cpresents a circuit and connections to interface with circuit array X. The antenna is connected to node P, and node E is connected to Earth ground preferably via a copper rod which has been inserted at least a few inches into Earth ground soil. In this configuration, the antenna receives and rectifies the voltage difference between Earth ground and the elevated antenna. Component SG1represents a Switched-Gas such as a neon gas bulb or similar. SG1may also be comprised of a Spark Gap device. When voltage across SG1is high enough, arcs through the gas or across the spark gap ensue, thereby charging capacitor C4in bursts. C4can be comprised of any type of dielectric composition or form, but it is preferably a ceramic, mylar, polypropalene, mica, or polyester, capacitor of value between 1 uF to 1000 uF, and preferably possesses a voltage rating of 300 volts or greater. As the rectifier array of X charges and exceeds the breakdown voltage of the spark gap or switched-gas bulb (SG1), an arc will occur and current will flow from array X through diode D4and into capacitor C4. C4charges in this pulsed fashion. C4may charge to hundreds of volts depending upon the output of array X. It should be noted that in some cases disconnecting diode D4from node P may be necessary in order to get array X to charge substantially. As mentioned previously, array X may not charge substantially unless all digital multi-meter test probes, test loading, or test connections are removed. In an alternative embodiment, the spark gap or gas bulb SG1could be replaced with the switchable load circuits ofFIG.3eor3fwherein when the forward bias voltage of the diode array in the LOAD is exceeded, array X will discharge into capacitor C4and charge it. Capacitor C4may take a substantial amount of time to charge whether utilizing a spark gap, or switched-gas, or diodes, to control the discharge event, especially1fC4is many hundreds of uF in size. Reference designator Vst in the circuit represents the stored voltage on capacitor C4. Circuit block U may be connected to any, some, or all of the embodiments ofFIG.4din order to do useful operations. Circuit block U may also be connected to any, some, or all of the LOAD embodiments ofFIG.3. In an alternative embodiment, the circuits ofFIG.3a,3b, or3d, may be used to drive the antenna node of circuit block U and operate it without an elevated antenna. In this fashion, a low voltage galvanic cell and the voltage spikes (oscillations) on Vout of the up-converter inFIGS.3a,3b, and3d, may drive the antenna node of circuit block U and thereby create up to hundreds of volts stored on capacitor C4. The three embodiments ofFIG.4dmay be connected individually or in parallel to circuit block U. The first embodiment inFIG.4dpossesses a LAMP means (preferably a gas such as neon) and current limiting resistor R5, and can be useful to produce a large and prolonged burst of light. This may be useful for implementing elevated visual notifications, lighted decorations, or warnings. The second embodiment inFIG.4ddisplaying blocks U2, U3and UN, depicts a plurality of micro-circuit blocks which may be used to further rectify or regulate or process the voltage stored on capacitor C4in order to power other micro-circuits such as analog and digital circuits useful to do operative works. The third embodiment ofFIG.4dcomprises a speaker or speakers and capacitor C5which may be utilized to make an audible sonic tone, ultra-sonic tone, tones, or sonic bursts. SG2represents a Spark Gap or Switched Gas acting as a switch, such as neon gas. Upon spark gap arcing or gas breakdown, the flowing electricity excites the speaker with a pulse of electrical current to make sonic tones or notes or acoustic wave transmissions. Connecting all 3 embodiments ofFIG.4din parallel with circuit block U may be useful to perform a plurality of useful operations in parallel. However, when doing so it may be necessary to adjust various circuit values and parameters in order to achieve optimal performance from blocks U and Y. The multiple circuit blocks presented in this disclosure may be connected in series or parallel configurations and orientations. FIG.4edepicts antenna placement with circuit blocks U and Y. If circuit blocks U and Y are elevated, then node E must be electrically routed downward to Earth ground and preferably to a copper rod inserted into the ground at least 3 inches. The antenna (23) is preferably elevated at least 5 feet above ground, but the antenna may be elevated to any height. Higher is generally better. The antenna may be comprised of any electrically conductive wire such as standard coax cable. In a preferred embodiment, simple and inexpensive coax cable may be utilized, wherein either the center copper conductor or the stranded wire shielding of the coax may be utilized as the antenna length. The antenna length may be between 1 and 10000 feet, but preferably the antenna is approximately 50-100 feet long. The antenna may be substantially shorter or substantially longer. FIG.4fdepicts an alternate embodiment wherein the antenna (24) hangs substantially downward and is substantially vertical in orientation. Conversely, in an alternate embodiment the antenna may point up and be raised substantially vertically, as opposed to hanging down. Coax cable may also be utilized in this embodiment, or similarly conductive electrical wire. FIG.4grepresents an alternative embodiment wherein the antenna may be in the form of a substantially helical coil, or a substantially flat-wound coil. For example, 100 feet of coax cable may be wound into a helical coil formation that is approximately 1 foot in diameter. Coax may also be wound into a flat-wound coil configuration. So may Romex cabling of any gauge.FIG.4gdepicts the antenna coil in a substantially vertical orientation, but the coil may alternatively be in a substantially horizontal orientation or any angled variance thereof. In embodiments4e,4f, and4g, substantially elevating the antenna may help yield best operations from the antenna array X. Faster flashing or bursting of the spark gap or gas bulb will make evident that more signal is being received by the antenna and electrical charge stored on array X. Embodiments of FIG.5 FIG.5adepicts a top view of a galvanic powered micro-chip (ref. numeral30). Tungsten, aluminum, and copper are commonly used in micro-chip fabrication processes in order to form the interconnecting metal layers over the semiconductor devices below. Copper is useful as a positive electrode for a galvanic cell, but other metals may be used. In a preferred embodiment, copper or a metal substantially comprised of copper, is utilized to form a metal plate area (ref. numeral31) on the top surface of the micro-chip. The plate area may be relatively small versus the top surface area of the chip, or relatively large versus the top surface area. In a preferred embodiment the normal silicon dioxide and silicon nitride insulating surface layers are removed or substantially un-fabricated, leaving the copper or upper metal layer exposed for use as a galvanic cell electrode. In an alternate embodiment there may be a plurality of surface modifications fabricated in the copper surface or top surface metal plate. These surface modifications may take the form of slots, squares, circles, ovals, or variations thereof. These surface modifications may be done to comply with foundry metal density limitations or rules for wafer fabrication, or to increase exposed surface area for galvanic reaction with electrolytes. The surface modifications may be placed across the entire metal surface area, or just a portion thereof. A plurality of bond pads are depicted with reference numerals32,33, and34. Bond pads may be utilized to electrically connect the micro-chip circuits with external circuits, devices, or systems, including supplemental or primary galvanic metals. An electrically insulating encapsulant such as glue or epoxy or a form of glass, may be applied over the bond pads and also the associated bond wiring interconnects (ref numerals35and36) to electrically isolate and protect portions of the micro-chip and interconnect wires from corrosion or interaction with the galvanic electrolyte. The electrically insulating encapsulant or covering (such as epoxy or glue or a form of glass) may also be applied to cover the semiconductor substrate and epitaxial layer structure (ref. numeral45). The micro-chip assembly may then be substantially impervious to placement in water-moistened soil, sea water, or other effective electrolyte fluid, and only the copper or metal plate (37) will react substantially with the electrolyte fluid, moistened soil, or sea water. In an alternate embodiment, it may also be necessary to similarly encapsulate, coat, or cover metal wiring connecting the micro-chip to other circuits (36) or galvanic metals or devices so as to isolate them from substantial galvanic reactions with dampened soil, sea water, or electrolyte solutions. In an alternate embodiment, an aluminum or tungsten plate is also exposed on the surface of the micro-chip with said aluminum or said tungsten forming the negative electrode for the galvanic cell. Aluminum or tungsten may serve as the negative electrode (Vn) of the galvanic cell, or other like-metals may be used instead. Copper may serve as the positive electrode (Vp) of the galvanic cell, or other like-metals may be used. Having multiple exposed metals on the upper micro-chip layer structure negates the need to have external metallic sheets or external masses of galvanic metals to power the micro-chip. Since copper and aluminum may be fabricated on different layers of the micro-chip, it may be necessary to remove any silicon dioxide or silicon nitride covering these metallic layers in the micro-chip stack so that they may be exposed for galvanic cell use. For example, copper may be the upper most metal layer on the micro-chip, and aluminum may reside in a layer below the copper, therein separated by a silicon dioxide insulation layer. As such, these metallic plates or metal masses may be fabricated substantially adjacent to one another in different layers so that they may both be exposed (37) for galvanic cell use. In an alternate embodiment of the invention, only an aluminum plate is fabricated on the top surface of the micro-chip. As such, an external mass of more positive metal (such as copper) may be needed to act as the positive electrode and electrically connected to a bond pad on the micro-chip for Vp interconnect to the micro-circuits below. In all previously described embodiments, the metals may be comprised wholly or merely substantially of aluminum, tungsten, zinc, copper, and similar. Either the Vp metal may reside exposed on the micro-chip, or the Vn metal may reside exposed. In an alternate embodiment, both metals may lay exposed on the micro-chip (37). One skilled in the art will recognize that not all micro-chip fabrication processes offer copper layers, and this detail may drive where and how Vp and Vn metals are implemented. The micro-chip fabrication processes may also determine whether aluminum or tungsten may be used. Electrolyte reactions with the exposed surface regions of the galvanic metals will determine to a large extent how much electricity may be generated, stored, and used by the micro-chip circuits. That said, external metal sheets or external metal masses may also be connected or supplemented in order to generate more electricity for micro-chip storage and functional operations. External metal sheets or masses may be accordingly connected to the micro-chip bond pads or circuits to provide additional galvanic generated electricity to the micro-chip circuits. The galvanic cell may also be supplemented by a secondary battery type including alkaline, nickel cadmium, lead acid, or similar. Stacking a plurality of micro-chips may present these same trade-offs and features. In an alternative embodiment, a micro-chip possessing copper layers may be stacked on top of a micro-chip possessing aluminum layers, thereby providing exposed aluminum and exposed copper for galvanic reactions on the stacked chip assembly. The chips may be stacked in same physical orientation, or alternate physical orientation, such as face to face, back to back, or back to face. FIG.5bdepicts a side view for a galvanic powered micro-chip assembly. Metallic vias are depicted with reference numerals38and39. They may be comprised of tungsten, or other suitable metal for interconnect. A plurality of vias may be used for interconnect within micro-chips. Vias may be fabricated using tungsten, aluminum, copper, zinc, or other metals available to the interconnection process and fabrication. Vias are a commonly a means to pass electricity and electrical signals between micro-chip layers, and also to pass electricity and electrical signals to a plurality of circuits (ref. numerals41,42, and43) implanted into the semiconductor substrate or epitaxial layer (ref. numeral44). Reference numeral46depicts an example transistor Gate of a CMOS transistor placed accordingly between Drain and Source diffusions or contacts. A plurality of transistors may be fabricated in a micro-chip or in a micro-chip stack. Transistors may be fabricated as Metal Oxide Semiconductor Field Effect Transistors (MOSFET's), Bipolar Junction Transistors (BJT's), Insulated Gate Bipolar Transistors (IGBTs), Junction Field Effect Transistors (JFET's), Fin-shaped Field Effect Transistors (FINFETs), Carbon Nano-tube Transistors (CNT's), and any other known transistor type. They may be mixed in any manner for use on or in the micro-chips. FIG.5cdepicts a block diagram and general circuit flow architecture for a galvanic powered micro-chip. It is merely one example of a circuit flow, and other reasonable flows may also be implemented. In this embodiment, a metal plate (such as copper) near the micro-chip surface (37) may be interconnected below using vias (39) leading to one or a plurality of capacitors (C6) and integrated circuits below. This metal plate is the positive electrode of the galvanic cell (Vp). Conversely, the negative electrode (Vn) may be routed to circuits below using vias (38) and lead to similar capacitor arrangements and quantities, as well as integrated circuits. The negative electrode node may be a metal such as zinc or aluminum or tungsten which is more negative than the Vp metal (such as copper). The Vn metal may or may not be external to the micro-chip. In an alternate embodiment, the aluminum or tungsten or zinc may be affixed to the surface of the micro-chip using epoxy or similar adhesives or eutectic attachment means. Any of the galvanic metals may be perforated or slotted. Metals may be wholly or just substantially copper, zinc, aluminum, tungsten, or similar. In much the same way that the various galvanic cell components ofFIG.1could be formed and utilized, a micro-chip assembly or chip stack may also be placed in water moistened soil, sea water, or functional electrolyte solutions, and surrounded in whole or in part by zinc or aluminum or tungsten sheeting (negative electrode). Copper tubing or copper sheeting may also be placed similarly. A galvanic powered micro-chip may be used in conjunction with the embodiments ofFIG.1through4, or in a derivative form. A containment vessel for a galvanic powered micro-chip or chip stack may have a plurality of similar features as depicted in the embodiments described forFIGS.1through4. The negative electrode surface area may be 1 to 10 times the surface area of the positive electrode (such as copper), but it can also be substantially more or substantially less without departing from the spirit of the invention. Sizing of surface areas boils down to how much electricity is required, the life of the device, the size of the device, the cost of the device, and the complexity of the device. One skilled in the art will appreciate the trade offs. Galvanic cells may be formed from numerous different metals as long as a usable voltage difference exists between them. The relatively small DC voltage difference of a galvanic cell may then be up-converted or down-converted in voltage, and also regulated for appropriate use by electrical circuits. Capacitor C6denotes a storage element or elements either within the micro-chip structure or external to the micro-chip. C6stores electrical charge from the galvanic cell and thereby feeds the up-conversion, down-conversion, or regulation circuits depicted in circuit block U2. These conversion and regulation circuits may be designed into the micro-chip and thereby be connected to a plurality of other circuits in the micro-chip depicted by U3and UN. The voltage and current required to power a micro-chip varies with semiconductor process and circuit architecture. The up-conversion, down-conversion, and regulation circuits are optimized to take the electrical energy stored in C6and create the voltage levels necessary to power the micro-chip and various associated circuits, either on the micro-chip or off of it. FIG.5ddepicts a side view of a galvanic powered micro-chip stacked assembly. The assembly may comprise a plurality of micro-chips in the stack-up. They may be stacked face to face, back to back, or face to face. The face (top) being the upper most metal layer or silicon dioxide layer or silicon nitride layer, and the back (bottom) being the bottom most semiconductor layer. The chips may be fabricated using different semiconductor processes offering metals such as copper, aluminum, tungsten, zinc, or other metals useful. Metallic vias are denoted with reference numerals38and39and depict an example of a plurality of vias which may be utilized to pass electricity and signals between micro-chip stack layers and various circuit blocks. Vias may be fabricated with tungsten or aluminum or copper or zinc or other metals sufficient to form via interconnects between metal layers and chip stacks. Vias may pass electricity and electrical signals to a plurality of circuits (exemplified by ref. numerals41,42, and43) implanted into the semiconductor substrate or epitaxial layer (ref. numeral44). Reference numeral46depicts a transistor gate of a complimentary MOSFET transistor. A plurality of gates and transistors may reside on each micro-chip. Reference numeral46refers to an example of one transistor, but there may be a plurality of transistors on the micro-chips. Transistors may be fabricated as Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), Bipolar Junction Transistors (BJT's), Insulated Gate Bipolar Transistors (IGBTs), Junction Field Effect Transistors (JFETs), Fin-shaped Field Effect Transistors (FINFETs), Carbon Nano-tube Transistors (CNTs), and any other known transistor type. Micro-chips of any type of semiconductor fabrication process may be stacked on top of one another. Reference numeral48depicts an example boundary region or surface of contact between first and second stacked micro-chips. A plurality of stacked chips will accordingly possess boundary regions (48) between stacked chips. As with the embodiments described forFIGS.5aand5b, the stacked micro-chips may also possess multiple exposed surfaces, such as copper, aluminum, tungsten, zinc, or other metals useful for substantial galvanic reactions. Galvanic metals may also reside off-chip or on-chip. The off-chip metals may wholly power the chips, or merely supplement the on-chip galvanic metals. Embodiment selection is accordingly determined by cost, power, size, complexity, longevity, toxicity, and over all performance desires. FIG.5edepicts an example block diagram circuit architecture comprising a plurality of stacked galvanic powered micro-chips. In one embodiment, the top metal plate (such as copper) near the top surface of the micro-chip (37) is interconnected down below using vias (39) and leading to a plurality of capacitors (C6and C7) and integrated circuits below. This node may be the positive electrode of the galvanic cell (Vp). The negative electrode may be routed to circuits below using vias (38) and leading to a plurality of capacitors and integrated circuits. This negative electrode node may ultimately be connected to a metal such as zinc or tungsten or aluminum which is more negative than copper and may be external to the micro-chip stack. A positive electrode metal (such as copper) may also be external to the micro-chip stack. The negative electrode metals may also reside affixed and exposed on the top of the micro-chip stack. As such, a small DC voltage may be locally supplied to some or all of the micro-chip stack circuits using galvanic metals on or substantially near the micro-chips. In much the same way that any of the preceding embodiments were formed, fabricated, placed, structured, or utilized, a stacked micro-chip assembly may also be placed in water moistened soil, sea water, or other effective electrolyte solutions, and surrounded in whole or in part by sheeting or masses of various metal electrodes. A containment vessel or housing for a galvanic powered micro-chip or micro-chip stack may have a plurality of the features described in the preceding figures and descriptions. Further, galvanic powered micro-chips may also be placed inside of any of the embodiments previously described. A plurality of galvanic cell embodiments and implementations may be utilized together, in parallel or series. The metal surface area for a negative electrode is preferably 1 to 10 times the surface area of the positive electrode, but the surface area of either can be substantially more or substantially less. The metals shall be selected in order to achieve product goals, including simplicity, performance, toxicity, longevity, reliability, and cost. In an alternate embodiment, a tungsten or aluminum or zinc or copper mass may also reside exposed or affixed to any surface of the micro-chip stack. Galvanic cells may be formed from numerous different metals as long as a voltage difference exists between them. The relatively small DC voltage difference between the metal electrodes can then be up-converted or down-converted, and regulated for usage with the micro-chip stack. Capacitors C6and C7denote a plurality of electrical storage elements either within the micro-chip stack structure or external to the micro-chip stack. C6and C7store electrical charge from the galvanic reaction and feed up-conversion, down-conversion, or regulation circuits depicted by circuit block U2. These storage and conversion circuits may be designed into the micro-chip stack on any chip in the stack-up, and accordingly be connected to a plurality of other circuits in the micro-chip stack depicted by U3and UN. Signals and electricity may be passed between the micro-chip stack layers and between circuit blocks. Electrical signal connections and communications may be passed within each chip or throughout the chip stack using means such as bond wire connectivity, via connectivity, form-able metals such as lead or similar, capacitor coupling, radio frequency transmission, light emission, magnetic coupling, or RF coupling. The voltage and current required to power circuits in a micro-chip stack may vary with semiconductor fabrication processes and circuit architectures. The galvanic cells are sized accordingly for desired circuit requirements and operations. Up-conversion (DC to AC, or DC to DC conversion), down-conversion (DC to AC, or DC to DC conversion), and voltage regulation circuits are leveraged to take the galvanic cell energy or electrical energy stored in a plurality of capacitors such as C6and C7and create the voltage and current levels necessary to power the plurality of micro-chip circuits in the stack-up. In an alternate embodiment,FIGS.5a,5b,5c,5d, and5e, may make take the form of a water, electrolyte, soil, or moisture sensor. The sensor may be placed near water or electrolyte sources, such as in buildings, near washing machines, sinks, pipes, chemical processes, etc. A water, electrolyte, soil, or moisture sensor may also be placed in boats, homes, basements, or water traveling vessels. When intended substances find their way to the micro-chip sensor, the galvanic reaction may power-up the micro-chip or the micro-chip stack and initiate operations such as sending notification of a sensed problem or reaction via optical, electrical, or RF signaling means. This implementation may negate the need to have conventional sensors or conventional battery cells or power feeds to power micro-chip sensors. Communications or notifications from the micro-chips may be made by visual light, invisible light, audio, ultra-sonic frequency, radio frequency, or digitally communicated or coded means such as a cellular communication, an email notification, text message notification, digital bus communication or flag, or an app notification by way of a phone, computing device, or smart phone, or tablet device. Some exemplary circuits for implementing these features have been generally detailed in the numerous earlier embodiments and figures. One skilled in the art will appreciate the spirit of the invention and the many ways and methods in which these galvanic systems and devices may be formed, connected, fabricated, located, used, and combined. In yet another embodiment, capacitor C6may be substantially large in capacity versus the electrical charge generated by the relatively small metallic surface areas of the galvanic cell. C6may be a super-capacitor with a plurality of Farads in capacity. In this case, capacitor C6may take many minutes, hours, or days to charge-up substantially. After C6has charged sufficiently, a substantial amount of the stored electrical energy may be directed or provided to a micro-chip or micro-chip stack in a quick burst, or momentary usage. C6may therein be used for short burst of radio frequency or optical communications from the micro-chip stack assembly. Or the stored electricity in C6may be used to burst a substantial amount of power into lights or sound emitting devices for data communications or visual notifications. These visual and data notification means may include fiber optics, lasers, light emitting diodes, gaseous bulbs, and the associated driver circuits may reside in the micro-chip design or micro chip stack. In this fashion, the relatively low DC output from a galvanic cell may be overcome by storing substantial charge in capacitors before activating or powering up micro-circuits on the micro-chip or stack. In yet another embodiment, the DC voltage generated by the galvanic cell may be too high for the micro-chip transistors or circuits. This may occur with modern semiconductor or carbon nano-tube processes requiring very low DC voltages for operation. In this case, the micro-chip or micro-chip stack may possess down-conversion circuits such as DC to DC conversion, wherein the DC voltage of the galvanic cell is reduced and regulated to supply the appropriate lower DC voltage levels required by the transistors and circuits within the micro-chip or stack. A plurality of micro-chips may be stacked on top of one another in order to achieve a compact galvanic powered system of micro-chips. The interconnect between the micro-chips may be made using vias, form-able metals such as lead, inherent proximity, or by using bond wires stepping between the plurality chips. In another embodiment, vias, form-able metals, and bond wires may all be used for the interconnects between the chips in the stack. Signals and electricity may also be coupled capacitively, inductively, magnetically, optically, or resistively between the chips. FIG.5fdepicts an embodiment wherein 1 or more micro-chips are stacked on top of a metallic sheet (50) residing affixed to one end of a micro-chip or micro-chip stack. In preferred embodiment, the metallic sheet (50) is comprised substantially of zinc or aluminum or tungsten and resides on one end of the stack. The metallic sheet (50) may be epoxied, glued, or eutectic die attached (51) to the substrate material or epi-layer (47) wherein the negative electrode (such as zinc) provides Vn electrical potential to the chip stack through the epi-layer or substrate. In an alternate embodiment the metallic sheet (50) may be affixed (51) to the epi-layer or substrate (47) with a form-able metal such as lead or similar. The form-able metal interconnect may be substantially electrically conductive, or substantially non-conductive. In any of these embodiments, the metallic sheet (50) may be electrically connected to a bond pad via an interconnect wire so as to provide Vn to the chip-stack through a bond pad interconnect. In yet another embodiment, the metallic sheet (50) may serve as the positive electrode (copper) and be connected to the chip stack accordingly. In this embodiment, the exposed surface metal (37) may alternatively comprise the negative electrode (Vn) and be fabricated from a metal such as aluminum or tungsten or zinc. The embodiment depicted inFIG.5fmay have utility in reducing cost and improving the manufacturability of the galvanic powered chip stack. The chip stack may comprise 1 micro-chip or a plurality of micro-chips. The chips may be stacked in same physical orientation (face to back), or in opposing orientations (back to back, or face to face), or a mixture of both (back to back, or front to back). Reference numeral49generally depicts where an electrically insulating encapsulant may be formed or deposited over the micro-chip assembly excluding the exterior surface of the upper plate (37) and the lower metallic sheet (50) which are substantially exposed for galvanic reactions. In this embodiment, the micro-chip assembly is substantially protected and electrically isolated. The encapsulant such as epoxy or glue may also cover the bond pads, electrically isolating them from galvanic processes and protecting them. Interconnects denoted by reference numeral36may also be encapsulated or coated with teflon or epoxy or plastics or glass so as to inhibit any reactions of the metallic wires with the galvanic cell chemistry. In cases where these interconnect wires would contact the galvanic cell chemistry, they are preferably insulated but in some embodiments the affects may be negligible and protective coatings may not be necessary, still yielding acceptable circuit operations and life expectancy for the systems and devices (e.g. flood monitor, emergency sensor, etc.). For example, in applications where the galvanic assembly is only briefly exposed to electrolyte solutions once in its useful life. FIG.5gpresents an electrical interconnect block diagram for a stacked embodiment ofFIG.5fwhere metallic sheets (37and50) are utilized to substantially power a micro-chip or micro-chips, in whole or in part. In one embodiment, the metallic sheet50may be zinc or tungsten or aluminum and serve as Vn. Metallic sheet37may be copper or similar and serve as Vp. In an alternate embodiment, the galvanic metals may be swapped and metallic sheet37may be comprised of aluminum or tungsten or zinc and serve as Vn, and metallic sheet50may be comprised of copper or similar and serve as Vp. The metal sheets may be placed in a plurality of useful orientations and locations as described in previous embodiments. CONCLUSION, RAMIFICATIONS, AND SCOPE The disclosed embodiments are illustrative, not restrictive. While numerous embodiments of the invention have been described, it is understood that the invention can be appreciated in a variety of environmental circumstances, means, combinations, systems, devices, and methods. Although the present invention has been described in considerable detail with reference to certain versions thereof, other versions and combinations are possible. Therefore, the spirit and scope of the invention and claims should not be limited to the description of the preferred versions contained therein. All features disclosed in this specification (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Each feature disclosed is only one example of a generic series of equivalent or similar features or embodiments. | 78,435 |
11862984 | While the following detailed description will be given with respect to certain illustrative embodiments, it should be understood that the drawings are not necessarily to scale and the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In addition, in certain instances, details which are not necessary for an understanding of the disclosed subject matter or which render other details too difficult to perceive may have been omitted. It should therefore be understood that this disclosure is not limited to the particular embodiments disclosed and illustrated herein, but rather to a fair reading of the entire disclosure and claims, as well as any equivalents thereto. Additional, different, or fewer components and methods may be included in the systems and methods. DETAILED DESCRIPTION In the following description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. Referring now to the drawings and with specific reference toFIG.1, a wireless power transfer system10is illustrated. The wireless power transfer system10provides for the wireless transmission of electrical signals, such as, but not limited to, electrical energy, electrical power, electrical power signals, electromagnetic energy, and electronically transmittable data (“electronic data”). As used herein, the term “electrical power signal” refers to an electrical signal transmitted specifically to provide meaningful electrical energy for charging and/or directly powering a load, whereas the term “electronic data signal” refers to an electrical signal that is utilized to convey data across a medium. The wireless power transfer system10provides for the wireless transmission of electrical signals via near field magnetic coupling. As shown in the embodiment ofFIG.1, the wireless power transfer system10includes one or more wireless transmission systems20and one or more wireless receiver systems30. A wireless receiver system30is configured to receive electrical signals from, at least, a wireless transmission system20. As illustrated, the wireless transmission system(s)20and wireless receiver system(s)30may be configured to transmit electrical signals across, at least, a separation distance or gap17. A separation distance or gap, such as the gap17, in the context of a wireless power transfer system, such as the system10, does not include a physical connection, such as a wired connection. There may be intermediary objects located in a separation distance or gap, such as, but not limited to, air, a counter top, a casing for an electronic device, a plastic filament, an insulator, a mechanical wall, among other things; however, there is no physical, electrical connection at such a separation distance or gap. Thus, the combination of two or more wireless transmission systems20and wireless receiver system30create an electrical connection without the need for a physical connection. As used herein, the term “electrical connection” refers to any facilitation of a transfer of an electrical current, voltage, and/or power from a first location, device, component, and/or source to a second location, device, component, and/or destination. An “electrical connection” may be a physical connection, such as, but not limited to, a wire, a trace, a via, among other physical electrical connections, connecting a first location, device, component, and/or source to a second location, device, component, and/or destination. Additionally or alternatively, an “electrical connection” may be a wireless power and/or data transfer, such as, but not limited to, magnetic, electromagnetic, resonant, and/or inductive field, among other wireless power and/or data transfers, connecting a first location, device, component, and/or source to a second location, device, component, and/or destination. Further, whileFIGS.1-2may depict wireless power signals and wireless data signals transferring only from one antenna (e.g., a transmission antenna21) to another antenna (e.g., a receiver antenna31and/or a transmission antenna21), it is certainly possible that a transmitting antenna21may transfer electrical signals and/or couple with one or more other antennas and transfer, at least in part, components of the output signals or magnetic fields of the transmitting antenna21. Such transmission may include secondary and/or stray coupling or signal transfer to multiple antennas of the system10. In some cases, the gap17may also be referenced as a “Z-Distance,” because, if one considers antennas21,31each to be disposed substantially along respective common X-Y planes, then the distance separating the antennas21,31is the gap in a “Z” or “depth” direction. However, flexible and/or non-planar coils are certainly contemplated by embodiments of the present disclosure and, thus, it is contemplated that the gap17may not be uniform, across an envelope of connection distances between the antennas21,31. It is contemplated that various tunings, configurations, and/or other parameters may alter the possible maximum distance of the gap17, such that electrical transmission from the wireless transmission system20to the wireless receiver system30remains possible. Moreover, in an embodiment, the characteristics of the gap17can change during use, such as by an increase or decrease in distance and/or a change in relative device orientations. The wireless power transfer system10operates when the wireless transmission system20and the wireless receiver system30are coupled. As used herein, the terms “couples,” “coupled,” and “coupling” generally refer to magnetic field coupling, which occurs when a transmitter and/or any components thereof and a receiver and/or any components thereof are coupled to each other through a magnetic field. Such coupling may include coupling, represented by a coupling coefficient (k), that is at least sufficient for an induced electrical power signal, from a transmitter, to be harnessed by a receiver. Coupling of the wireless transmission system20and the wireless receiver system30, in the system10, may be represented by a resonant coupling coefficient of the system10and, for the purposes of wireless power transfer, the coupling coefficient for the system10may be in the range of about 0.01 and 0.9. As illustrated, at least one wireless transmission system20is associated with an input power source12. The input power source12may be operatively associated with a host device, which may be any electrically operated device, circuit board, electronic assembly, dedicated charging device, or any other contemplated electronic device. Example host devices, with which the wireless transmission system20may be associated therewith, include, but are not limited to including, a device that includes an integrated circuit, a portable computing device, storage medium for electronic devices, charging apparatus for one or multiple electronic devices, dedicated electrical charging devices, among other contemplated electronic devices. The input power source12may be or may include one or more electrical storage devices, such as an electrochemical cell, a battery pack, and/or a capacitor, among other storage devices. Additionally or alternatively, the input power source12may be any electrical input source (e.g., any alternating current (AC) or direct current (DC) delivery port) and may include connection apparatus from said electrical input source to the wireless transmission system20(e.g., transformers, regulators, conductive conduits, traces, wires, or equipment, goods, computer, camera, mobile phone, and/or other electrical device connection ports and/or adaptors, such as but not limited to USB ports and/or adaptors, among other contemplated electrical components). Electrical energy received by the wireless transmission system(s)20is then used for at least two purposes: to provide electrical power to internal components of the wireless transmission system20and to provide electrical power to the transmission antenna21. The transmission antenna21is configured to wirelessly transmit the electrical signals conditioned and modified for wireless transmission by the wireless transmission system20via near-field magnetic coupling (NFMC). Near-field magnetic coupling enables the transfer of signals wirelessly through magnetic induction between the transmission antenna21and one or more of receiving antenna31of, or associated with, the wireless receiver system30, another transmission antenna21, or combinations thereof. Near-field magnetic coupling may be and/or be referred to as “inductive coupling,” which, as used herein, is a wireless power transmission technique that utilizes an alternating electromagnetic field to transfer electrical energy between two antennas. Such inductive coupling is the near field wireless transmission of magnetic energy between two magnetically coupled coils that are tuned to resonate at a similar frequency. Accordingly, such near-field magnetic coupling may enable efficient wireless power transmission via resonant transmission of confined magnetic fields. Further, such near-field magnetic coupling may provide connection via “mutual inductance,” which, as defined herein is the production of an electromotive force in a circuit by a change in current in a second circuit magnetically coupled to the first. In one or more embodiments, the inductor coils of either the transmission antenna21or the receiver antenna31are strategically positioned to facilitate reception and/or transmission of wirelessly transferred electrical signals through near field magnetic induction. Antenna operating frequencies may comprise relatively high operating frequency ranges, examples of which may include, but are not limited to, 6.78 MHz (e.g., in accordance with the Rezence and/or Airfuel interface standard and/or any other proprietary interface standard operating at a frequency of 6.78 MHz), 13.56 MHz (e.g., in accordance with the NFC standard, defined by ISO/IEC standard 18092), 27 MHz, and/or an operating frequency of another proprietary operating mode. The operating frequencies of the antennas21,31may be operating frequencies designated by the International Telecommunications Union (ITU) in the Industrial, Scientific, and Medical (ISM) frequency bands, including not limited to 6.78 MHz, 13.56 MHz, and 27 MHz, which are designated for use in wireless power transfer. The transmitting antenna and the receiving antenna of the present disclosure may be configured to transmit and/or receive electrical power having a magnitude that ranges from about 10 milliwatts (mW) to about 500 watts (W). In one or more embodiments the inductor coil of the transmitting antenna21is configured to resonate at a transmitting antenna resonant frequency or within a transmitting antenna resonant frequency band. A “coil” of a wireless power antenna (e.g., the transmission antenna21, the receiver antenna31), as defined herein, is any conductor, wire, or other current carrying material, configured to resonate for the purposes of wireless power transfer and optional wireless data transfer. As known to those skilled in the art, a “resonant frequency” or “resonant frequency band” refers a frequency or frequencies wherein amplitude response of the antenna is at a relative maximum, or, additionally or alternatively, the frequency or frequency band where the capacitive reactance has a magnitude substantially similar to the magnitude of the inductive reactance. In one or more embodiments, the transmitting antenna resonant frequency is at a high frequency, as known to those in the art of wireless power transfer. The wireless receiver system30may be associated with at least one electronic device14, wherein the electronic device14may be any device that requires electrical power for any function and/or for power storage (e.g., via a battery and/or capacitor). Additionally, the electronic device14may be any device capable of receipt of electronically transmissible data. For example, the device may be, but is not limited to being, a handheld computing device, a mobile device, a portable appliance, a computer peripheral, an integrated circuit, an identifiable tag, a kitchen utility device, an electronic tool, an electric vehicle, a game console, a robotic device, a wearable electronic device (e.g., an electronic watch, electronically modified glasses, altered-reality (AR) glasses, virtual reality (VR) glasses, among other things), a portable scanning device, a portable identifying device, a sporting good, an embedded sensor, an Internet of Things (IoT) sensor, IoT enabled clothing, IoT enabled recreational equipment, industrial equipment, medical equipment, a medical device a tablet computing device, a portable control device, a remote controller for an electronic device, a gaming controller, among other things. For the purposes of illustrating the features and characteristics of the disclosed embodiments ofFIGS.1-10, arrow-ended lines are utilized to illustrate transferrable and/or communicative signals and various patterns are used to illustrate electrical signals that are intended for power transmission and electrical signals that are intended for the transmission of data and/or control instructions. Solid lines indicate signal transmission of electrical energy over a physical and/or wireless power transfer, in the form of power signals that are, ultimately, utilized in wireless power transmission from the wireless transmission system20to the wireless receiver system30. Further, dotted lines are utilized to illustrate electronically transmittable data signals, which ultimately may be wirelessly transmitted from the wireless transmission system20to the wireless receiver system30. While the systems and methods herein illustrate the transmission of wirelessly transmitted energy, wireless power signals, wirelessly transmitted power, wirelessly transmitted electromagnetic energy, and/or electronically transmittable data, it is certainly contemplated that the systems, methods, and apparatus disclosed herein may be utilized in the transmission of only one signal, various combinations of two signals, or more than two signals and, further, it is contemplated that the systems, method, and apparatus disclosed herein may be utilized for wireless transmission of other electrical signals in addition to or uniquely in combination with one or more of the above mentioned signals. In some examples, the signal paths of solid or dotted lines may represent a functional signal path, whereas, in practical application, the actual signal is routed through additional components en route to its indicated destination. For example, it may be indicated that a data signal routes from a communications apparatus to another communications apparatus; however, in practical application, the data signal may be routed through an amplifier, then through a transmission antenna, to a receiver antenna, where, on the receiver end, the data signal is decoded by a respective communications device of the receiver. Turning now toFIGS.2-3, the wireless power transfer system10is illustrated as a block diagram including example sub-systems of both the wireless transmission systems20and the wireless receiver systems30. The wireless transmission systems20may include, at least, a power conditioning system40, a transmission control system26, a demodulation circuit70, a transmission tuning system24, and the transmission antenna21. A first portion of the electrical energy input from the input power source12may be configured to electrically power components of the wireless transmission system20such as, but not limited to, the transmission control system26. A second portion of the electrical energy input from the input power source12is conditioned and/or modified for wireless power transmission, to the wireless receiver system30, via the transmission antenna21. Accordingly, the second portion of the input energy is modified and/or conditioned by the power conditioning system40. While not illustrated, it is certainly contemplated that one or both of the first and second portions of the input electrical energy may be modified, conditioned, altered, and/or otherwise changed prior to receipt by the power conditioning system40and/or transmission control system26, by further contemplated subsystems (e.g., a voltage regulator, a current regulator, switching systems, fault systems, safety regulators, among other things). Referring more specifically now toFIG.3, with continued reference toFIGS.1and2, subcomponents and/or systems of the transmission control system26are illustrated. The transmission control system26may include a sensing system50, a transmission controller28, a driver48, a memory27and a demodulation circuit70. The transmission controller28may be any electronic controller or computing system that includes, at least, a processor which performs operations, executes control algorithms, stores data, retrieves data, gathers data, controls and/or provides communication with other components and/or subsystems associated with the wireless transmission system20, and/or performs any other computing or controlling task desired. The transmission controller28may be a single controller or may include more than one controller disposed to control various functions and/or features of the wireless transmission system20. Functionality of the transmission controller28may be implemented in hardware and/or software and may rely on one or more data maps relating to the operation of the wireless transmission system20. To that end, the transmission controller28may be operatively associated with the memory27. The memory may include one or more of internal memory, external memory, and/or remote memory (e.g., a database and/or server operatively connected to the transmission controller28via a network, such as, but not limited to, the Internet). The internal memory and/or external memory may include, but are not limited to including, one or more of a read only memory (ROM), including programmable read-only memory (PROM), erasable programmable read-only memory (EPROM or sometimes but rarely labelled EROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDR SDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data rate synchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5, a flash memory, a portable memory, and the like. Such memory media are examples of nontransitory machine readable and/or computer readable memory media. While particular elements of the transmission control system26are illustrated as independent components and/or circuits (e.g., the driver48, the memory27, the sensing system50, among other contemplated elements) of the transmission control system26, such components may be integrated with the transmission controller28. In some examples, the transmission controller28may be an integrated circuit configured to include functional elements of one or both of the transmission controller28and the wireless transmission system20, generally. As illustrated, the transmission controller28is in operative association, for the purposes of data transmission, receipt, and/or communication, with, at least, the memory27, the power conditioning system40, the driver48, and the sensing system50. The driver48may be implemented to control, at least in part, the operation of the power conditioning system40. In some examples, the driver48may receive instructions from the transmission controller28to generate and/or output a generated pulse width modulation (PWM) signal to the power conditioning system40. In some such examples, the PWM signal may be configured to drive the power conditioning system40to output electrical power as an alternating current signal, having an operating frequency defined by the PWM signal. In some examples, PWM signal may be configured to generate a duty cycle for the AC power signal output by the power conditioning system40. In some such examples, the duty cycle may be configured to be about 50% of a given period of the AC power signal. The sensing system may include one or more sensors, wherein each sensor may be operatively associated with one or more components of the wireless transmission system20and configured to provide information and/or data. The term “sensor” is used in its broadest interpretation to define one or more components operatively associated with the wireless transmission system20that operate to sense functions, conditions, electrical characteristics, operations, and/or operating characteristics of one or more of the wireless transmission system20, the wireless receiving system30, the input power source12, the host device11, the transmission antenna21, the receiver antenna31, along with any other components and/or subcomponents thereof. As illustrated in the embodiment ofFIG.4, the sensing system50may include, but is not limited to including, a thermal sensing system52, an object sensing system54, a receiver sensing system56, a current sensor57, and/or any other sensor(s)58. Within these systems, there may exist even more specific optional additional or alternative sensing systems addressing particular sensing aspects required by an application, such as, but not limited to: a condition-based maintenance sensing system, a performance optimization sensing system, a state-of-charge sensing system, a temperature management sensing system, a component heating sensing system, an IoT sensing system, an energy and/or power management sensing system, an impact detection sensing system, an electrical status sensing system, a speed detection sensing system, a device health sensing system, among others. The object sensing system54, may be a foreign object detection (FOD) system. Each of the thermal sensing system52, the object sensing system54, the receiver sensing system56, the current sensor57and/or the other sensor(s)58, including the optional additional or alternative systems, are operatively and/or communicatively connected to the transmission controller28. The thermal sensing system52is configured to monitor ambient and/or component temperatures within the wireless transmission system20or other elements nearby the wireless transmission system20. The thermal sensing system52may be configured to detect a temperature within the wireless transmission system20and, if the detected temperature exceeds a threshold temperature, the transmission controller28prevents the wireless transmission system20from operating. Such a threshold temperature may be configured for safety considerations, operational considerations, efficiency considerations, and/or any combinations thereof. In a non-limiting example, if, via input from the thermal sensing system52, the transmission controller28determines that the temperature within the wireless transmission system20has increased from an acceptable operating temperature to an undesired operating temperature (e.g., in a non-limiting example, the internal temperature increasing from about 200 Celsius (C) to about 50° C., the transmission controller28prevents the operation of the wireless transmission system20and/or reduces levels of power output from the wireless transmission system20. In some non-limiting examples, the thermal sensing system52may include one or more of a thermocouple, a thermistor, a negative temperature coefficient (NTC) resistor, a resistance temperature detector (RTD), and/or any combinations thereof. As depicted inFIG.4, the transmission sensing system50may include the object sensing system54. The object sensing system54may be configured to detect one or more of the wireless receiver system30and/or the receiver antenna31, thus indicating to the transmission controller28that the receiver system30is proximate to the wireless transmission system20. Additionally or alternatively, the object sensing system54may be configured to detect presence of unwanted objects in contact with or proximate to the wireless transmission system20. In some examples, the object sensing system54is configured to detect the presence of an undesired object. In some such examples, if the transmission controller28, via information provided by the object sensing system54, detects the presence of an undesired object, then the transmission controller28prevents or otherwise modifies operation of the wireless transmission system20. In some examples, the object sensing system54utilizes an impedance change detection scheme, in which the transmission controller28analyzes a change in electrical impedance observed by the transmission antenna20against a known, acceptable electrical impedance value or range of electrical impedance values. Additionally or alternatively, the object sensing system54may utilize a quality factor (Q) change detection scheme, in which the transmission controller28analyzes a change from a known quality factor value or range of quality factor values of the object being detected, such as the receiver antenna31. The “quality factor” or “Q” of an inductor can be defined as (frequency (Hz)×inductance (H))/resistance (ohms), where frequency is the operational frequency of the circuit, inductance is the inductance output of the inductor and resistance is the combination of the radiative and reactive resistances that are internal to the inductor. “Quality factor,” as defined herein, is generally accepted as an index (figure of measure) that measures the efficiency of an apparatus like an antenna, a circuit, or a resonator. In some examples, the object sensing system54may include one or more of an optical sensor, an electro-optical sensor, a Hall Effect sensor, a proximity sensor, and/or any combinations thereof. In some examples, the quality factor measurements, described above, may be performed when the wireless power transfer system10is performing in band communications. The receiver sensing system56is any sensor, circuit, and/or combinations thereof configured to detect a presence of any wireless receiving system that may be couplable with the wireless transmission system20. In some examples, the receiver sensing system56and the object sensing system54may be combined, may share components, and/or may be embodied by one or more common components. In some examples, if the presence of any such wireless receiving system is detected, wireless transmission of electrical energy, electrical power, electromagnetic energy, and/or data by the wireless transmission system20to said wireless receiving system is enabled. In some examples, if the presence of a wireless receiver system is not detected, continued wireless transmission of electrical energy, electrical power, electromagnetic energy, and/or data is prevented from occurring. Accordingly, the receiver sensing system56may include one or more sensors and/or may be operatively associated with one or more sensors that are configured to analyze electrical characteristics within an environment of or proximate to the wireless transmission system20and, based on the electrical characteristics, determine presence of a wireless receiver system30. The current sensor57may be any sensor configured to determine electrical information from an electrical signal, such as a voltage or a current, based on a current reading at the current sensor57. Components of an example current sensor57are further illustrated inFIG.5, which is a block diagram for the current sensor57. The current sensor57may include a transformer51, a rectifier53, and/or a low pass filter55, to process the AC wireless signals, transferred via coupling between the wireless receiver system(s)20and wireless transmission system(s)30, to determine or provide information to derive a current (ITx) or voltage (VTx) at the transmission antenna21. The transformer51may receive the AC wireless signals and either step up or step down the voltage of the AC wireless signal, such that it can properly be processed by the current sensor. The rectifier53may receive the transformed AC wireless signal and rectify the signal, such that any negative voltages remaining in the transformed AC wireless signal are either eliminated or converted to opposite positive voltages, to generate a rectified AC wireless signal. The low pass filter55is configured to receive the rectified AC wireless signal and filter out AC components (e.g., the operating or carrier frequency of the AC wireless signal) of the rectified AC wireless signal, such that a DC voltage is output for the current (ITx) and/or voltage (VTx) at the transmission antenna21. FIG.6is a block diagram for a demodulation circuit70for the wireless transmission system(s)20, which is used by the wireless transmission system20to simplify or decode components of wireless data signals of an alternating current (AC) wireless signal, prior to transmission of the wireless data signal to the transmission controller28. The demodulation circuit includes, at least, a slope detector72and a comparator74. In some examples, the demodulation circuit70includes a set/reset (SR) latch76. In some examples, the demodulation circuit70may be an analog circuit comprised of one or more passive components (e.g., resistors, capacitors, inductors, diodes, among other passive components) and/or one or more active components (e.g., operational amplifiers, logic gates, among other active components). Alternatively, it is contemplated that the demodulation circuit70and some or all of its components may be implemented as an integrated circuit (IC). In either an analog circuit or IC, it is contemplated that the demodulation circuit may be external of the transmission controller28and is configured to provide information associated with wireless data signals transmitted from the wireless receiver system30to the wireless transmission system20. The demodulation circuit70is configured to receive electrical information (e.g., ITx, VTx) from at least one sensor (e.g., a sensor of the sensing system50), detect a change in such electrical information, determine if the change in the electrical information meets or exceeds one of a rise threshold or a fall threshold. If the change exceeds one of the rise threshold or the fall threshold, the demodulation circuit70generates an output signal and also generates and outputs one or more data alerts. Such data alerts are received by the transmitter controller28and decoded by the transmitter controller28to determine the wireless data signals. In other words, in an embodiment, the demodulation circuit70is configured to monitor the slope of an electrical signal (e.g., slope of a voltage signal at the power conditioning system32of a wireless receiver system30) and to output an indication when said slope exceeds a maximum slope threshold or undershoots a minimum slope threshold. Such slope monitoring and/or slope detection by the communications system70is particularly useful when detecting or decoding an amplitude shift keying (ASK) signal that encodes the wireless data signals in-band of the wireless power signal (which is oscillating at the operating frequency). In an ASK signal, as noted above, the wireless data signals are encoded by damping the voltage of the magnetic field between the wireless transmission system20and the wireless receiver system30. Such damping and subsequent re-rising of the voltage in the field is performed based on an underlying encoding scheme for the wireless data signals (e.g., binary coding, Manchester coding, pulse-width modulated coding, among other known or novel coding systems and methods). The receiver of the wireless data signals (e.g., the wireless transmission system20in this example) can then detect rising and falling edges of the voltage of the field and decode said rising and falling edges to demodulate the wireless data signals. Ideally, an ASK signal would rise and fall instantaneously, with no discernable slope between the high voltage and the low voltage for ASK modulation; however, in reality, there is a finite amount of time that passes when the ASK signal transitions from the “high” voltage to the “low” voltage and vice versa. Thus, the voltage or current signal to be sensed by the demodulation circuit70will have some slope or rate of change in voltage when transitioning. By configuring the demodulation circuit70to determine when said slope meets, overshoots and/or undershoots such rise and fall thresholds, established based on the known maximum/minimum slope of the carrier signal at the operating frequency, the demodulation circuit can accurately detect rising and falling edges of the ASK signal. Thus, a relatively inexpensive and/or simplified circuit may be utilized to at least partially decode ASK signals down to notifications or alerts for rising and falling slope instances. As long as the transmission controller28is programmed to understand the coding schema of the ASK modulation, the transmission controller28will expend far less computational resources than would have been needed to decode the leading and falling edges directly from an input current or voltage sense signal from the sensing system50. To that end, as the computational resources required by the transmission controller28to decode the wireless data signals are significantly decreased due to the inclusion of the demodulation circuit70, the demodulation circuit70may significantly reduce BOM of the wireless transmission system20, by allowing usage of cheaper, less computationally capable processor(s) for or with the transmission controller28. The demodulation circuit70may be particularly useful in reducing the computational burden for decoding data signals, at the transmitter controller28, when the ASK wireless data signals are encoded/decoded utilizing a pulse-width encoded ASK signals, in-band of the wireless power signals. A pulse-width encoded ASK signal is a signal wherein the data is encoded as a percentage of a period of a signal. For example, a two-bit pulse width encoded signal may encode a start bit as 20% of a period between high edges of the signal, encode “1” as 40% of a period between high edges of the signal, and encode “0” as 60% of a period between high edges of the signal, to generate a binary encoding format in the pulse width encoding scheme. Thus, as the pulse width encoding relies solely on monitoring rising and falling edges of the ASK signal, the periods between rising times need not be constant and the data signals may be asynchronous or “unclocked.” Examples of pulse width encoding and systems and methods to perform such pulse width encoding are explained in greater detail in U.S. patent application Ser. No. 16/735,342 titled “Systems and Methods for Wireless Power Transfer Including Pulse Width Encoded Data Communications,” to Michael Katz, which is commonly owned by the owner of the instant application and is hereby incorporated by reference in its entirety, for all that it teaches without exclusion of any part thereof. As noted above, slope detection, and hence in-band transfer of data, may become ineffective or inefficient when the signal strength varies from the parameters relied upon during design. For example, when the relative positions of the data sender and data receiver vary significantly during use of the system, the electromagnetic coupling between sender and receiver coils or antennas will also vary. Data detection and decoding are optimized for a particular coupling may fail or underperform at other couplings. As such, a high sensitivity non-saturating detection system is needed to allow the system to operate in environments wherein coupling changes dynamically. For example, referring toFIGS.7, the signal created by the high pass filter71of the slope detector72, prior to being amplified by OPSD, will vary as a result of varying coupling (as will the power signal, but, for the purposes of the discussion of in-band data, it has now been filtered out at this point). Thus, the difference in magnitude of the amplified signals will vary by even more. At the upper end, substantially improved coupling may cause saturation of OPSD, at said upper end, if the system is tuned for small signal detection. Similarly, substantially degraded coupling may result in an undetectable signal if the system is tuned for high, good, and/or fair coupling. Moreover, a pre-amp signal with a positive offset may result in clipped (e.g., saturated) positive signals, post-amplification, unless gain is reduced; however, the reduced gain may in turn render negative signals undetectable. Additionally, a varying load at the receiver may affect the signal, necessitating the amplification of the data signal at the slope detector72. As such, instability in coupling is generally not well-tolerated by inductive charging systems, since it causes the filtered and amplified signal to vary too greatly. For example, a phone placed into a fitted dock will stay in a specific location relative to the dock, and any coupling therebetween will remain relatively constant. However, a phone placed on a desktop with an inductive charging station under the desktop may not maintain a fixed relative location, nor a fixed relative orientation and, thus, the range of coupling between the transmitter and the receiver of the phone may vary during the charging process. Further, consider a wireless power system configured for directly powering and/or charging a medical device, while the medical device resides within a human body. Due to natural displacement and/or internal movement of organic elements of the human body, the medical device may not maintain constant location, relative to the body and/or an associated charger positioned outside of the body, and, thus, the transmitter and receiver may couple at a wide range of high, good, fair, low, and/or insufficient coupling levels. Further still, consider a computer peripheral being charged by a charging mat on a user's desk. It may be desired to charge said peripheral, such as a mouse or other input device, during use of the device; such use of the peripheral will necessarily alter coupling during use, as it will be moved regularly, with respect to positioning of the transmitting charging mat. The effect caused by a difference in the coupling coefficient k can be illustrated by a few non-limiting examples. Consider a case wherein k=0.041, representing fairly strong coupling. In this case, the induced voltage delta (Vdelta) may be about 160 mV, with the corresponding amplified signal running between a peak of 3.15V and a nadir of 0.45V, for a swing of about 2.70V around a DC offset of 1.86V (i.e., 1.35V above and below the DC offset value). Now consider a case in the same system wherein a coupling value of 0.01 is exhibited, representing fairly weak coupling. This weakening could happen due to relative movement, intervening materials, or other circumstance. Now Vdeltamay be about 15 mV, with the corresponding amplified signal running between a peak of 1.94V and a nadir of 1.77V, for a swing of about 140 mV around a DC offset of 1.86V (i.e., about 70 mV above and below the DC offset value). As can be seen from this example, while the strongly coupled case yields robust signals, the weakly coupled case yields very small signals atop a fairly large offset. While perhaps generally detectable, these signal level present a significant risk of data errors and consequently lowered throughput. Moreover, while there is room for increased amplification, the level of amplification, especially given the DC offset, is constrained by the saturation level of the available economical operational amplifier circuits, which, in some examples may be about 4.0V. However, in an embodiment, automatic gain control in amplification is combined with a voltage offset in slope detection to allow the system to adapt to varying degrees of coupling. This is especially helpful in situations where the physical locations of the coupled devices are not tightly constrained during coupling. Continuing with the example ofFIG.7, in the illustrated circuit72, the bias voltage V′Biasfor slope detection is provided by a voltage divider77(including linked resistors RB1, RB2, RB3), which provides a voltage between Vinand ground based on a control voltage VHB. Given the control voltage VHB, the bias voltage V′Biasis set by adjusting a resistance in the voltage divider. In this connection, one of the resistors, e.g., RB3, may be a variable resistor, such as a digitally adjustable potentiometer, with the specific resistance being generated via an adaptive bias and gain protocol to be described below, e.g., Rbias. Similarly, in the illustrated circuit72, the output voltage VSDprovided to the next stage, comparator74, is first amplified at a level set by a voltage divider80(including linked resistors RA1, RA2, RA3), based on the control voltage VHAto generate V′SD(slope detection signal). The amplification of VSDto generate V′SD(amplified slope detection signal) is similarly set via a variable potentiometer in the voltage divider, e.g., RA1, being set to a specific value, e.g., Rgaingenerated via an adaptive bias and gain protocol to be described later below. With respect to the aforementioned, non-limiting example, with automatic gain and bias in slope detection, the circuit is configured to accommodate a Vamp slope deltaof between 400 mv and 2.2V, and a Vamp DCoffset of between 1.8V and 2.2V. In order to determine appropriate offsets and gains, the system may employ a beaconing sequence state. The beaconing sequence ensures that the transmitter is generally able to detect the receiver at all possible allowed coupling positions and orientations. Referring still toFIGS.7, the slope detector72includes a high pass filter71and an optional stabilizing circuit73. The high pass filter71is configured to monitor for higher frequency components of the AC wireless signals and may include, at least, a filter capacitor (CHF) and a filter resistor (RHF). The values for CHFand RHFare selected and/or tuned for a desired cutoff frequency for the high pass filter71. In some examples, the cutoff frequency for the high pass filter71may be selected as a value greater than or equal to about 1-2 kHz, to ensure adequately fast slope detection by the slope detector72, when the operating frequency of the system10is on the order of MHz (e.g., an operating frequency of about 6.78 MHz). In some examples, the high pass filter71is configured such that harmonic components of the detected slope are unfiltered. In view of the current sensor57ofFIG.5, the high pass filter71and the low pass filter55, in combination, may function as a bandpass filter for the demodulation circuit70. OPSDis any operational amplifier having an adequate bandwidth for proper signal response, for outputting the slope of VTx, but low enough to attenuate components of the signal that are based on the operating frequency and/or harmonics of the operating frequency. Additionally or alternatively, OPSDmay be selected to have a small input voltage range for VTx, such that OPSDmay avoid unnecessary error or clipping during large changes in voltage at VTx. Further, an input bias voltage (VBias) for OPSDmay be selected based on values that ensure OPSDwill not saturate under boundary conditions (e.g., steepest slopes, largest changes in VTx). It is to be noted, and is illustrated in Plot B ofFIG.8, that when no slope is detected, the output of the slope detector72will be VBias. As the passive components of the slope detector72will set the terminals and zeroes for a transfer function of the slope detector72, such passive components must be selected to ensure stability. To that end, if the desired and/or available components selected for CHFand RHFdo not adequately set the terminals and zeros for the transfer function, additional, optional stability capacitor(s) CSTmay be placed in parallel with RHFand stability resistor RSTmay be placed in the input path to OPSD. Output of the slope detector72(Plot B representing VSD) may approximate the following equation: VSD=-RHFCHFdVdt+VBias Thus, VSDwill approximate to VBias, when no change in voltage (slope) is detected, and Output VSDof the slope detector72is represented in Plot B. As can be seen, the value of VSDapproximates VBiaswhen no change in voltage (slope) is detected, whereas VSDwill output the change in voltage (dV/dt), as scaled by the high pass filter71, when VTxrises and falls between the high voltage and the low voltage of the ASK modulation. The output of the slope detector72, as illustrated in Plot B, may be a pulse, showing slope of VTxrise and fall. VSDis output to the comparator circuit(s)74, which is configured to receive VSD, compare VSDto a rising rate of change for the voltage (VSUp) and a falling rate of change for the voltage (VSLo). If VSDexceeds or meets VSUp, then the comparator circuit will determine that the change in VTxmeets the rise threshold and indicates a rising edge in the ASK modulation. If VSDgoes below or meets VSLow, then the comparator circuit will determine that the change in VTxmeets the fall threshold and indicates a falling edge of the ASK modulation. It is to be noted that VSUpand VSLomay be selected to ensure a symmetrical triggering. FIG.8is an exemplary timing diagram illustrating signal shape or waveform at various stages or sub-circuits of the demodulation circuit70. The input signal to the demodulation circuit70is illustrated inFIG.8as Plot A, showing rising and falling edges from a “high” voltage (VHigh) perturbation on the transmission antenna21to a “low” voltage (VLow) perturbation on the transmission antenna21. The voltage signal of Plot A may be derived from, for example, a current (ITx) sensed at the transmission antenna21by one or more sensors of the sensing system50. Such rises and falls from VHighto VLowmay be caused by load modulation, performed at the wireless receiver system(s)30, to modulate the wireless power signals to include the wireless data signals via ASK modulation. As illustrated, the voltage of Plot A does not cleanly rise and fall when the ASK modulation is performed; rather, a slope or slopes, indicating rate(s) of change, occur during the transitions from VHighto VLowand vice versa. As illustrated inFIG.7, the slope detector72includes a high pass filter71, an operation amplifier (OpAmp) OPSD, and an optional stabilizing circuit73. The high pass filter71is configured to monitor for higher frequency components of the AC wireless signals and may include, at least, a filter capacitor (CHF) and a filter resistor (RHF). The values for CHFand RHFare selected and/or tuned for a desired cutoff frequency for the high pass filter71. In some examples, the cutoff frequency for the high pass filter71may be selected as a value greater than or equal to about 1-2 kHz, to ensure adequately fast slope detection by the slope detector72, when the operating frequency of the system10is on the order of MHz (e.g., an operating frequency of about 6.78 MHz). In some examples, the high pass filter71is configured such that harmonic components of the detected slope are unfiltered. In view of the current sensor57ofFIG.5, the high pass filter71and the low pass filter55, in combination, may function as a bandpass filter for the demodulation circuit70. OPSDis any operational amplifier having an adequate bandwidth for proper signal response, for outputting the slope of VTx, but low enough to attenuate components of the signal that are based on the operating frequency and/or harmonics of the operating frequency. Additionally or alternatively, OPSDmay be selected to have a small input voltage range for VTx, such that OPSDmay avoid unnecessary error or clipping during large changes in voltage at VTx. Further, an input bias voltage (VBias) for OPSDmay be selected based on values that ensure OPSDwill not saturate under boundary conditions (e.g., steepest slopes, largest changes in VTx). It is to be noted, and is illustrated in Plot B ofFIG.8, that when no slope is detected, the output of the slope detector72will be VBias. As the passive components of the slope detector72will set the terminals and zeroes for a transfer function of the slope detector72, such passive components must be selected to ensure stability. To that end, if the desired and/or available components selected for CHFand RHFdo not adequately set the terminals and zeros for the transfer function, additional, optional stability capacitor(s) CSTmay be placed in parallel with RHFand stability resistor RSTmay be placed in the input path to OPSD. Output of the slope detector72(Plot B representing VSD) may approximate the following equation: VSD=-RHFCHFdVdt+VBias Thus, VSDwill approximate to VBias, when no change in voltage (slope) is detected, and output VSDof the slope detector72is represented in Plot B. As can be seen, the value of VSDapproximates VBiaswhen no change in voltage (slope) is detected, whereas VSDwill output the change in voltage (dV/dt), as scaled by the high pass filter71, when VTxrises and falls between the high voltage and the low voltage of the ASK modulation. The output of the slope detector72, as illustrated in Plot B, may be a pulse, showing slope of VTxrise and fall. VSDis output to the comparator circuit(s)74, which is configured to receive VSD, compare VSDto a rising rate of change for the voltage (VSUp) and a falling rate of change for the voltage (VSLo). If VSDexceeds or meets VSUp, then the comparator circuit will determine that the change in VTxmeets the rise threshold and indicates a rising edge in the ASK modulation. If VSDgoes below or meets VSLow, then the comparator circuit will determine that the change in VTxmeets the fall threshold and indicates a falling edge of the ASK modulation. It is to be noted that VSUpand VSLomay be selected to ensure a symmetrical triggering. In some examples, such as the comparator circuit74illustrated inFIG.6, the comparator circuit74may comprise a window comparator circuit. In such examples, the VSUpand VSLomay be set as a fraction of the power supply determined by resistor values of the comparator circuit74. In some such examples, resistor values in the comparator circuit may be configured such that VSup=Vin[RU2RU1+RU2]VSLo=Vin[RL2RL1+RL2] where Vin is a power supply determined by the comparator circuit74. When VSDexceeds the set limits for VSUpor VSLo, the comparator circuit74triggers and pulls the output (VCout) low. Further, while the output of the comparator circuit74could be output to the transmission controller28and utilized to decode the wireless data signals by signaling the rising and falling edges of the ASK modulation, in some examples, the SR latch76may be included to add noise reduction and/or a filtering mechanism for the slope detector72. The SR latch76may be configured to latch the signal (Plot C) in a steady state to be read by the transmitter controller28, until a reset is performed. In some examples, the SR latch76may perform functions of latching the comparator signal and serve as an inverter to create an active high alert out signal. Accordingly, the SR latch76may be any SR latch known in the art configured to sequentially excite when the system detects a slope or other modulation excitation. As illustrated, the SR latch76may include NOR gates, wherein such NOR gates may be configured to have an adequate propagation delay for the signal. For example, the SR latch76may include two NOR gates (NORUp, NORLo), each NOR gate operatively associated with the upper voltage output78of the comparator74and the lower voltage output79of the comparator74. In some examples, such as those illustrated in Plot C, a reset of the SR latch76is triggered when the comparator circuit74outputs detection of VSUp(solid plot on Plot C) and a set of the SR latch76is triggered when the comparator circuit74outputs VSLo(dashed plot on Plot C). Thus, the reset of the SR latch76indicates a falling edge of the ASK modulation and the set of the SR latch76indicates a rising edge of the ASK modulation. Accordingly, as illustrated in Plot D, the rising and falling edges, indicated by the demodulation circuit70, are input to the transmission controller28as alerts, which are decoded to determine the received wireless data signal transmitted, via the ASK modulation, from the wireless receiver system(s)30. The incoming signal VTX exemplified in the plots ofFIG.8does not lead to excess bias or saturation because the values of VBIASand VGare at appropriate levels, but the coupling environment may change (e.g., from strong to weak coupling), such that the existing VBIASand VGare no longer appropriate and would no longer allow accurate signal detection. However, automatic gain and bias routines are applied as described herein to continually evaluate the system behavior and set VBIASand VGsuch that accurate signal detection is provided throughout the range of allowable coupling strengths. Referring now toFIG.9, and with continued reference toFIGS.1-4, a block diagram illustrating an embodiment of the power conditioning system40is illustrated. At the power conditioning system40, electrical power is received, generally, as a DC power source, via the input power source12itself or an intervening power converter, converting an AC source to a DC source (not shown). A voltage regulator46receives the electrical power from the input power source12and is configured to provide electrical power for transmission by the antenna21and provide electrical power for powering components of the wireless transmission system21. Accordingly, the voltage regulator46is configured to convert the received electrical power into at least two electrical power signals, each at a proper voltage for operation of the respective downstream components: a first electrical power signal to electrically power any components of the wireless transmission system20and a second portion conditioned and modified for wireless transmission to the wireless receiver system30. As illustrated inFIG.3, such a first portion is transmitted to, at least, the sensing system50, the transmission controller28, and the communications system29; however, the first portion is not limited to transmission to just these components and can be transmitted to any electrical components of the wireless transmission system20. The second portion of the electrical power is provided to an amplifier42of the power conditioning system40, which is configured to condition the electrical power for wireless transmission by the antenna21. The amplifier may function as an inverter, which receives an input DC power signal from the voltage regulator46and generates an AC as output, based, at least in part, on PWM input from the transmission control system26. The amplifier42may be or include, for example, a power stage invertor, such as a single field effect transistor (FET), a dual field effect transistor power stage invertor or a quadruple field effect transistor power stage invertor. The use of the amplifier42within the power conditioning system40and, in turn, the wireless transmission system20enables wireless transmission of electrical signals having much greater amplitudes than if transmitted without such an amplifier. For example, the addition of the amplifier42may enable the wireless transmission system20to transmit electrical energy as an electrical power signal having electrical power from about 10 mW to about 500 W. In some examples, the amplifier42may be or may include one or more class-E power amplifiers. Class-E power amplifiers are efficiently tuned switching power amplifiers designed for use at high frequencies (e.g., frequencies from about 1 MHz to about 1 GHz). Generally, a single-ended class-E amplifier employs a single-terminal switching element and a tuned reactive network between the switch and an output load (e.g., the antenna21). Class E amplifiers may achieve high efficiency at high frequencies by only operating the switching element at points of zero current (e.g., on-to-off switching) or zero voltage (off to on switching). Such switching characteristics may minimize power lost in the switch, even when the switching time of the device is long compared to the frequency of operation. However, the amplifier42is certainly not limited to being a class-E power amplifier and may be or may include one or more of a class D amplifier, a class EF amplifier, an H invertor amplifier, and/or a push-pull invertor, among other amplifiers that could be included as part of the amplifier42. Turning now toFIG.10and with continued reference to, at least,FIGS.1and2, the wireless receiver system30is illustrated in further detail. The wireless receiver system30is configured to receive, at least, electrical energy, electrical power, electromagnetic energy, and/or electrically transmittable data via near field magnetic coupling from the wireless transmission system20, via the transmission antenna21. As illustrated inFIG.9, the wireless receiver system30includes, at least, the receiver antenna31, a receiver tuning and filtering system34, a power conditioning system32, a receiver control system36, and a voltage isolation circuit70. The receiver tuning and filtering system34may be configured to substantially match the electrical impedance of the wireless transmission system20. In some examples, the receiver tuning and filtering system34may be configured to dynamically adjust and substantially match the electrical impedance of the receiver antenna31to a characteristic impedance of the power generator or the load at a driving frequency of the transmission antenna20. As illustrated, the power conditioning system32includes a rectifier33and a voltage regulator35. In some examples, the rectifier33is in electrical connection with the receiver tuning and filtering system34. The rectifier33is configured to modify the received electrical energy from an alternating current electrical energy signal to a direct current electrical energy signal. In some examples, the rectifier33is comprised of at least one diode. Some non-limiting example configurations for the rectifier33include, but are not limited to including, a full wave rectifier, including a center tapped full wave rectifier and a full wave rectifier with filter, a half wave rectifier, including a half wave rectifier with filter, a bridge rectifier, including a bridge rectifier with filter, a split supply rectifier, a single phase rectifier, a three phase rectifier, a voltage doubler, a synchronous voltage rectifier, a controlled rectifier, an uncontrolled rectifier, and a half controlled rectifier. As electronic devices may be sensitive to voltage, additional protection of the electronic device may be provided by clipper circuits or devices. In this respect, the rectifier33may further include a clipper circuit or a clipper device, which is a circuit or device that removes either the positive half (top half), the negative half (bottom half), or both the positive and the negative halves of an input AC signal. In other words, a clipper is a circuit or device that limits the positive amplitude, the negative amplitude, or both the positive and the negative amplitudes of the input AC signal. Some non-limiting examples of a voltage regulator35include, but are not limited to, including a series linear voltage regulator, a buck convertor, a low dropout (LDO) regulator, a shunt linear voltage regulator, a step up switching voltage regulator, a step down switching voltage regulator, an inverter voltage regulator, a Zener controlled transistor series voltage regulator, a charge pump regulator, and an emitter follower voltage regulator. The voltage regulator35may further include a voltage multiplier, which is as an electronic circuit or device that delivers an output voltage having an amplitude (peak value) that is two, three, or more times greater than the amplitude (peak value) of the input voltage. The voltage regulator35is in electrical connection with the rectifier33and configured to adjust the amplitude of the electrical voltage of the wirelessly received electrical energy signal, after conversion to AC by the rectifier33. In some examples, the voltage regulator35may an LDO linear voltage regulator; however, other voltage regulation circuits and/or systems are contemplated. As illustrated, the direct current electrical energy signal output by the voltage regulator35is received at the load16of the electronic device14. In some examples, a portion of the direct current electrical power signal may be utilized to power the receiver control system36and any components thereof; however, it is certainly possible that the receiver control system36, and any components thereof, may be powered and/or receive signals from the load16(e.g., when the load16is a battery and/or other power source) and/or other components of the electronic device14. The receiver control system36may include, but is not limited to including, a receiver controller38, a communications system39and a memory37. The receiver controller38may be any electronic controller or computing system that includes, at least, a processor which performs operations, executes control algorithms, stores data, retrieves data, gathers data, controls and/or provides communication with other components and/or subsystems associated with the wireless receiver system30. The receiver controller38may be a single controller or may include more than one controller disposed to control various functions and/or features of the wireless receiver system30. Functionality of the receiver controller38may be implemented in hardware and/or software and may rely on one or more data maps relating to the operation of the wireless receiver system30. To that end, the receiver controller38may be operatively associated with the memory37. The memory may include one or both of internal memory, external memory, and/or remote memory (e.g., a database and/or server operatively connected to the receiver controller38via a network, such as, but not limited to, the Internet). The internal memory and/or external memory may include, but are not limited to including, one or more of a read only memory (ROM), including programmable read-only memory (PROM), erasable programmable read-only memory (EPROM or sometimes but rarely labelled EROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDR SDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data rate synchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5), a flash memory, a portable memory, and the like. Such memory media are examples of nontransitory computer readable memory media. Further, while particular elements of the receiver control system36are illustrated as subcomponents and/or circuits (e.g., the memory37, the communications system39, among other contemplated elements) of the receiver control system36, such components may be external of the receiver controller38. In some examples, the receiver controller38may be and/or include one or more integrated circuits configured to include functional elements of one or both of the receiver controller38and the wireless receiver system30, generally. As used herein, the term “integrated circuits” generally refers to a circuit in which all or some of the circuit elements are inseparably associated and electrically interconnected so that it is considered to be indivisible for the purposes of construction and commerce. Such integrated circuits may include, but are not limited to including, thin-film transistors, thick-film technologies, and/or hybrid integrated circuits. In some examples, the wireless power transmission system20may be configured to transmit power over a large charge area, within which the wireless power receiver system30may receive said power. A “charge area” may be an area associated with and proximate to a wireless power transmission system20and/or a transmission antenna21and within said area a wireless power receiver30is capable of coupling with the transmission system20or transmission antenna21at a plurality of points within the charge area. To that end, it is advantageous, both for functionality and user experience, that the plurality of points for coupling within a charge area include as many points as possible and with as much of a consistent ability to couple with a receiver system30, within the given charge area. In some examples, a “large charge area” may be a charge area wherein the X-Y axis spatial freedom is within an area bounded by a width (across the area, or in an “X” axis direction) of about 150 mm to about 500 mm and bounded by a length (height of the area, or in an “Y” axis direction) of about 50 mm to about 350 mm. While the following antennas21disclosed are applicable to “large area” or “large charge area” wireless power transmission antennas, the teachings disclosed herein may also be applicable to transmission or receiver antennas having smaller or larger charge areas, then those discussed above. It is advantageous for large area power transmitters to be designed with maximum uniformity of power transmission in mind. Thus, it may be advantageous to design such transmission antennas21with uniformity ratio in mind. “Uniformity ratio,” as defined herein, refers to the ratio of a maximum coupling, between a wireless transmission system20and wireless receiver system30, to a minimum coupling between said systems20,30, wherein said coupling values are determined by measuring or determining a coupling between the systems20,30at a plurality of points at which the wireless receiver system30and/or antenna31are placed within the charge area of the transmission antenna21. In other words, the uniformity ratio is a ratio between the coupling when the receiver antenna31is positioned at a point, relative to the transmission antenna21area, that provides the highest coupling (CMAX) versus the coupling when the receiver antenna31is positioned at a point, relative to the charge area of the transmission antenna21, that provides for the lowest coupling (CMIN). Thus, uniformity ratio for a charge area (UAREA) may be defined as: UAREA=CMAX/CMIN. To that end, a perfectly uniform charge area would have a uniformity ratio of 1, as CMAX=CMINfor a fully uniform charge area. Further, while uniformity ratio can be enhanced by using more turns, coils, and/or other resonant bodies within an antenna, increasing such use of more conductive metals to maximize uniformity ratio may give rise to cost concerns, bill of material concerns, environmental concerns, and/or sustainability concerns, among other known drawbacks from inclusion of more conductive materials. To that end, the following transmission antennas21may be designed by balancing uniformity ratio considerations with cost, environmental, and/or sustainability considerations. In other words, the following transmission antennas21may be configured to achieve an increased (e.g., maximized) uniformity ratio, while reducing (e.g., minimizing) the use or the length of conductive wires and/or traces. Further, while the following antennas21may be embodied by PCB or flex PCB antennas, in some examples, the following antennas21may be wire wound antennas that eschew the use of any standard PCB substrate. By reducing or perhaps even eliminating the use of PCB substrate, cost and or environmental concerns associated with PCB substrates may be reduced and/or eliminated. Turning now toFIG.11, an example of a wireless power transmission antenna921A, which may be utilized as the transmission antenna21, for transmitting wireless power to a receiver system30over a large charge area, is illustrated. The antenna921A may be utilized as the transmission antenna21in any of the aforementioned wireless transmission systems20. The transmission antenna(s)925include multiple transmission coils925, wherein at least one transmission coil is a source coil925A and at least one transmission coil925is an internal repeater coil925B. The source coil925A is comprised of a first continuous conductive wire924A and includes a first outer turn953A and a first inner turn951A. While illustrated with only one first outer turn953A and one first inner turn951A, it is certainly contemplated that the antenna921A may include multiple outer turns953A and inner turns951A. The source coil925A is configured to connect to one or more electronic components120of the wireless transmission system20. The first conductive wire begins at a first source terminal926, which leads to or is part of the beginning of the first outer turn951A, and ends at a second source terminal, which is associated or is part of the ending928of the first inner turn951A. The internal repeater coil925B may take a similar shape to that of the source coil925A, but is not directly, electrically connected to the one or more electrical components120of the wireless transmission system20. Rather, the internal repeater coil925B is a repeater configured to have a repeater current induced in it by the source coil925A. As defined herein, a “repeater” is an antenna or coil that is configured to relay magnetic fields emanating between a transmission antenna (e.g., the source coil925A) and one or both of a receiver antenna31and one or more other antennas or coils, when such subsequent coils or antennas are configured as repeaters. Thus, the internal repeater coil925B may be configured to relay electrical energy and/or data via NMFC from the initial transmitting antenna (e.g., the source coil925A) to a receiver antenna31or to another repeating antenna or coil. In one or more embodiments, such repeating coils or antennas (e.g., the repeater coil925B) comprise an inductor coil capable of resonating at a frequency that is about the same as the resonating frequency of the initial transmitting antenna (e.g. the source coil925A) and the receiver antenna31. Further, it is certainly possible that an initial transmitting antenna may transfer electrical signals and/or couple with one or more other antennas (repeaters or receivers) and transfer, at least in part, components of the output signals or magnetic fields of the transmitting antenna. Such transmission may include secondary and/or stray coupling or signal transfer to multiple antennas of the system(s)10,20,30. As mentioned, the coil925B is referred to as an “internal repeater” to either the transmission antenna921,21and/or the wireless transmission system20, as it is contained as part of a common system20or antenna921,21. An “internal repeater” as defined herein is a repeater coil or antenna that is utilized as part of a unitary antenna, rather than as a repeater outside the bounds of the overall system. For example, a user of the wireless power transmission system20would not know the difference between a system20with an internal repeater and one in which all coils are wired to the electrical components120, so long as both systems are housed in an opaque mechanical housing (e.g., a mechanical housing960). Internal repeaters may be beneficial for use in unitary wireless transmission antennas because they allow for longer wires for coils, without introducing electromagnetic interference (EMI) that are associated with longer wires connected to a common wired signal source. Additionally or alternatively, use of internal repeaters may be beneficial in improving metal resiliency and/or uniformity ratio for the wireless transmission antenna(s)21. Configuration of the inner turns951and outer turns953, with respect to one another, of the coils925is designed for controlling a direction of current flow through each of the coils925. Current flow direction is illustrated by the dotted lines inFIG.11. As illustrated, the current may enter the source coil925A, from the one or more electrical components120, at the first source terminal at the beginning of the first outer turn953A and then flow through the first outer turn in a first source coil direction. Said source coil direction may be, for example, a clockwise direction, as illustrated. Then, at the end of the first outer turn953A, where the first outer turn953A turns into the first inner turn951A, the current will change directions to a second source direction, which is substantially opposite of the first source direction. In some examples and as illustrated, the second source direction may be a counter-clockwise direction, which is substantially opposite of the clockwise direction of the current flow through the first outer turn953A. The internal repeater coil925B is configured such that a current is induced in it by the source coil925A and direction(s) of the current induced in the internal repeater coil925B is/are illustrated by the dotted lines inFIG.11. The induced current of the internal repeater coil925B may have a first repeater direction, flowing through the second outer turn953B of the internal repeater coil925B. The first repeater direction may be, for example and as illustrated, a counter-clockwise direction. Then, at the end of the second outer turn953B, where the second outer turn953B turns into the second inner turn951B, the current will change directions to a second repeater direction, which is substantially opposite of the first repeater direction, In some examples and as illustrated, the second source direction may be a clockwise direction, which is substantially opposite of the counter-clockwise direction of the current flow through the second outer turn953B. As illustrated and described, the first repeater direction (counter-clockwise) may be substantially opposite of the first source direction (clockwise). Thus, as one views the antenna921both from left-to-right and from top-to-bottom, the current direction reverses from turn to turn. By reversing current directions from turn-to-turn both laterally (side to side) and from top-to-bottom, optimal field uniformity may be maintained. By reversing current directions amongst inner and outer turns951,953, both laterally and top-to-bottom, a receiver antenna31travelling across the charge area of the antenna921will more often be positioned more closer-to-perpendicular with the magnetic field emanating from the antenna921. Thus, as a receiver antenna31will best couple with the transmission antenna921at points of perpendicularity with the magnetic field, the charge area generated by the antenna921will have greater uniformity than if all of the turns951,953carried the current in a common direction. As illustrated, the source coil925A and the internal repeater coil925B may be configured to be housed in a common, unitary housing960. By utilizing the internal repeater coil925B, rather than one larger source coil, EMI benefits may be seen, as a shorter wire connected to the source may reduce EMI issues. Additionally, by utilizing the internal repeater coil925B, the aforementioned reversals of current direction may be better achieved, which enhances uniformity and metal resilience in the transmission antenna921. In some examples, while the internal repeater coil925B may be a “passive” inductor (e.g., not connected directly, by wired means, to a power source), it still may be connected to one or more components of a repeater tuning system923A. The repeater tuning system923A may include one or more components, such as a tuning capacitor, configured to tune the internal repeater coil925B to operate at an operating frequency similar to that of the source coil925A and/or any receiver antenna(s)31, to which the repeater coil925B intends to transfer wireless power. The repeater tuning system923A may be positioned, in a signal path of the internal repeater coil925B, connecting the beginning of the second outer turn953B and the ending of the second inner turn951B, as illustrated. One or more of the source coil925A, the internal repeater coil925B, and combinations thereof may form or combine to form a substantially rectangular shape, as illustrated. In some examples, such substantially rectangular shape(s) of one or more of the source coil925A, the internal repeater coil925B, and combinations thereof may additionally have rounded edges, as illustrated inFIG.11. FIG.12illustrates an example, non-limiting embodiment of the receiver antenna31that may be used with any of the systems, methods, and/or apparatus disclosed herein. In the illustrated embodiment, the antenna31, is a flat spiral coil configuration. Non-limiting examples can be found in U.S. Pat. Nos. 9,941,743, 9,960,628, 9,941,743 all to Peralta et al.; U.S. Pat. No. 9,948,129, 10,063,100 to Singh et al.; U.S. Pat. No. 9,941,590 to Luzinski; U.S. Pat. No. 9,960,629 to Rajagopalan et al.; and U.S. Patent App. Nos. 2017/0040107, 2017/0040105, 2017/0040688 to Peralta et al.; all of which are assigned to the assignee of the present application and incorporated fully herein by reference. In addition, the antenna31may be constructed having a multi-layer-multi-turn (MLMT) construction in which at least one insulator is positioned between a plurality of conductors. Non-limiting examples of antennas having an MLMT construction that may be incorporated within the wireless transmission system(s)20and/or the wireless receiver system(s)30may be found in U.S. Pat. Nos. 8,610,530, 8,653,927, 8,680,960, 8,692,641, 8,692,642, 8,698,590, 8,698,591, 8,707,546, 8,710,948, 8,803,649, 8,823,481, 8,823,482, 8,855,786, 8,898,885, 9,208,942, 9,232,893, and 9,300,046 to Singh et al., all of which are assigned to the assignee of the present application are incorporated fully herein. These are merely exemplary antenna examples; however, it is contemplated that the antennas31may be any antenna capable of the aforementioned higher power, high frequency wireless power transfer. Turning now toFIG.13, an example wireless power receiver antenna131, which may be utilized as the receiver antenna31, is illustrated in a side cross-sectional view. As illustrated, the receiver antenna131includes a receiver coil133A and an internal repeater135. A top view of an example for the receiver coil133is illustrated inFIG.13Cand top views of the internal repeater coil135are illustrated inFIGS.13D,13E. The internal repeater coil135is provided as a passive mechanism for boosting or enhancing the power harvesting capabilities of the receiver coil133. The receiver coil133is directly electrically connected to one or more electrical components130of the wireless receiver system30, which may include, but are not limited to including, the receiver tuning system34, the power conditioning system32, the rectifier33, the voltage regulator35, the receiver control system36, the receiver controller38, among other electrical components. The internal repeater coil135is not directly connected to the one or more electrical components130, but rather receives wireless power signals from the wireless transmission system and transmits or repeats said signals to the receiver coil as repeated wireless power signals. In some examples, the receiver coil133may receive both the wireless power signals, from the wireless transmission system20, and the repeated wireless power signals from the internal repeater coil135; thus, the repeated wireless power signals may boost power harvesting or enhance wireless power signals, when compared to receipt by the receiver coil133, alone. As illustrated inFIG.13A, an insulator132A may be positioned between the receiver coil133A and the internal repeater coil135; thus, the coils133,135may be manufactured as a multi-layer structure, such as a multi-layer PCB or flexible PCB. The internal repeater coil135and the receiver coil133may be separated by a repeater separation gap138. In some examples, the repeater separation gap may be in a range of about 0.5 millimeters (mm) to about 3 mm. In some examples, such as the example repeaters ofFIGS.13D,13E, the repeater may be a simple one-turn coil, which affords the benefits of the repeater with reduced cost for manufacturing a one turn coil. Further, as illustrated, the internal repeater coil135may include a repeater tuning system134, which is configured to tune the repeater coil135to resonate at a similar or same operating frequency as that of the wireless power transmission system20and/or the wireless receiver system30. In some examples, such as the example illustrated inFIG.13E, the transmission tuning system134may be disposed within the turn of the internal repeater coil135. As illustrated in the example of the antenna131B ofFIG.13B, the repeater coil133B may be a multi-layer, multi-turn (MLMT) coil, like those discussed above with respect toFIG.12. Such an MLMT repeater coil133B may include, at least, a first layer136and a second layer137. The layers136,137may be separated by a second insulator132B and may be connected, in electrical parallel, at a via138. The automatic gain and bias control described herein may significantly reduce the BOM for the demodulation circuit, and the wireless transmission system as a whole, by allowing usage of cheaper, less computationally capable processor(s) for or with the transmission controller. The throughput and accuracy of an edge-detection coding scheme depends in large part upon the system's ability to quickly and accurately detect signal slope changes. These constraints may be better met in environments wherein the distance between, and orientations of, the sender and receiver change dynamically, or the magnitude of the received power signal and embedded data signal may change dynamically, via the disclosed automatic gain and bias control. This may allow reading of faint signals via appropriate gain, for example, while also avoiding saturation with respect to larger signals. The systems, methods, and apparatus disclosed herein are designed to operate in an efficient, stable and reliable manner to satisfy a variety of operating and environmental conditions. The systems, methods, and/or apparatus disclosed herein are designed to operate in a wide range of thermal and mechanical stress environments so that data and/or electrical energy is transmitted efficiently and with minimal loss. In addition, the system10may be designed with a small form factor using a fabrication technology that allows for scalability, and at a cost that is amenable to developers and adopters. In addition, the systems, methods, and apparatus disclosed herein may be designed to operate over a wide range of frequencies to meet the requirements of a wide range of applications. While illustrated as individual blocks and/or components of the wireless transmission system20, one or more of the components of the wireless transmission system20may combined and/or integrated with one another as an integrated circuit (IC), a system-on-a-chip (SoC), among other contemplated integrated components. To that end, one or more of the transmission control system26, the power conditioning system40, the sensing system50, the transmitter coil21, and/or any combinations thereof may be combined as integrated components for one or more of the wireless transmission system20, the wireless power transfer system10, and components thereof. Further, any operations, components, and/or functions discussed with respect to the wireless transmission system20and/or components thereof may be functionally embodied by hardware, software, and/or firmware of the wireless transmission system20. Similarly, while illustrated as individual blocks and/or components of the wireless receiver system30, one or more of the components of the wireless receiver system30may combined and/or integrated with one another as an IC, a SoC, among other contemplated integrated components. To that end, one or more of the components of the wireless receiver system30and/or any combinations thereof may be combined as integrated components for one or more of the wireless receiver system30, the wireless power transfer system10, and components thereof. Further, any operations, components, and/or functions discussed with respect to the wireless receiver system30and/or components thereof may be functionally embodied by hardware, software, and/or firmware of the wireless receiver system30. In an embodiment, a ferrite shield may be incorporated within the antenna structure to improve antenna performance. Selection of the ferrite shield material may be dependent on the operating frequency as the complex magnetic permeability (μ=μ′−j*μ″) is frequency dependent. The material may be a polymer, a sintered flexible ferrite sheet, a rigid shield, or a hybrid shield, wherein the hybrid shield comprises a rigid portion and a flexible portion. Additionally, the magnetic shield may be composed of varying material compositions. Examples of materials may include, but are not limited to, zinc comprising ferrite materials such as manganese-zinc, nickel-zinc, copper-zinc, magnesium-zinc, and combinations thereof. As used herein, the phrase “at least one of” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” does not require selection of at least one of each item listed; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. The predicate words “configured to”, “operable to”, and “programmed to” do not imply any particular tangible or intangible modification of a subject, but, rather, are intended to be used interchangeably. In one or more embodiments, a processor configured to monitor and control an operation or a component may also mean the processor being programmed to monitor and control the operation or the processor being operable to monitor and control the operation. Likewise, a processor configured to execute code can be construed as a processor programmed to execute code or operable to execute code. A phrase such as “an aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples of the disclosure. A phrase such as an “aspect” may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples of the disclosure. A phrase such an “embodiment” may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples of the disclosure. A phrase such as a “configuration” may refer to one or more configurations and vice versa. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” or as an “example” is not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the subject disclosure. While this specification contains many specifics, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of particular implementations of the subject matter. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub combination or variation of a sub combination. | 91,119 |
11862985 | DETAILED DESCRIPTION A wireless power system includes electronic devices such as wrist watches, cellular telephones, tablet computers, laptop computers, removable cases, electronic device accessories, wireless charging mats, wireless charging pucks, and/or other electronic equipment. These electronic devices have wireless power circuitry. For example, an electronic device may have a wireless power coil. Some devices use wireless power coils for transmitting wireless power signals. Other devices use wireless power coils for receiving transmitted wireless power signals. If desired, some of the devices in a wireless power system may have both the ability to transmit wireless signals and to receive wireless signals. A cellular telephone or other portable electronic device may, as an example, have a coil that can be used to receive wireless power signals from a charging puck or other wireless transmitting device and that can also be used to transmit wireless power to another wireless power device (e.g., another cellular telephone). A device with one or more wireless power coils that is used for transmitting and/or receiving wireless power signals may be referred to as a wireless power device. Devices with power transmitting capabilities may sometimes be referred to as wireless power transmitting devices or wireless power devices. Devices with power receiving capabilities may sometimes be referred to as wireless power receiving devices or wireless power devices. A wireless power system containing two or more wireless power devices is shown inFIG.1. As shown inFIG.1, wireless power system8may include wireless power devices10. Each wireless power device in system8may include a housing containing one or more components such as power source12, control circuitry14, wireless power circuitry16, input-output devices18, and alignment magnets20. The housing may be formed from polymer, metal, glass, ceramic, other materials, and/or combinations of these materials. Power source12may include an alternating-current-to-direct-current power adapter that converts wall power (mains power) from an alternating-current source to direct-current power to power the circuitry of device10and/or may include a source of direct-current power such as a battery. If desired, devices with batteries can be wirelessly charged by receiving wireless power signals from a wireless power transmitting device. Control circuitry14in each device10of system8is used in controlling the operation of system8. This control circuitry may include processing circuitry associated with microprocessors, power management units, baseband processors, digital signal processors, microcontrollers, system(s) on chips (SoCs), and/or application-specific integrated circuits with processing circuits. The processing circuitry implements desired control and communications features in devices10. For example, the processing circuitry may be used in processing user input, handling negotiations between devices10, sending and receiving in-band and out-of-band data, making measurements, estimating power losses, determining power transmission levels, and otherwise controlling the operation of system8. Control circuitry14in system8may be configured to perform operations in system8using hardware (e.g., dedicated hardware or circuitry), firmware and/or software. Software code for performing operations in system8and other data is stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) in control circuitry8. The software code may sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory (NVRAM), one or more hard drives (e.g., magnetic drives or solid state drives), one or more removable flash drives or other removable media, or the like. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of control circuitry14. The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, a central processing unit (CPU) or other processing circuitry. Devices10use wireless power circuitry16to transmit and/or receive wireless power signals22between devices10. Wireless power circuitry16of each device10may include one or more coils. Configurations in which each device10has a single coil may sometimes be described herein as an example. Each device10in system10may have optional input-output devices18. Input-output devices18may include input devices for gathering user input and/or making environmental measurements and may include output devices for providing a user with output. As an example, input-output devices18may include a display for creating visual output, a speaker for presenting output as audio signals, light-emitting diode status indicator lights and other light-emitting components for emitting light that provides a user with status information and/or other information, haptic devices for generating vibrations and other haptic output, and/or other output devices. Input-output devices18may also include sensors for gathering input from a user and/or for making measurements of the surroundings of system8. Illustrative sensors that may be included in input-output devices18include three-dimensional sensors (e.g., three-dimensional image sensors such as structured light sensors that emit beams of light and that use two-dimensional digital image sensors to gather image data for three-dimensional images from light spots that are produced when a target is illuminated by the beams of light, binocular three-dimensional image sensors that gather three-dimensional images using two or more cameras in a binocular imaging arrangement, three-dimensional lidar (light detection and ranging) sensors, three-dimensional radio-frequency sensors, or other sensors that gather three-dimensional image data), cameras (e.g., infrared and/or visible cameras with respective infrared and/or visible digital image sensors and/or ultraviolet light cameras), gaze tracking sensors (e.g., a gaze tracking system based on an image sensor and, if desired, a light source that emits one or more beams of light that are tracked using the image sensor after reflecting from a user's eyes), touch sensors, buttons, capacitive proximity sensors, light-based (optical) proximity sensors such as infrared proximity sensors, other proximity sensors, force sensors, sensors such as contact sensors based on switches, gas sensors, pressure sensors, moisture sensors, magnetic sensors, audio sensors (microphones), ambient light sensors, optical sensors for making spectral measurements and other measurements on target objects (e.g., by emitting light and measuring reflected light), microphones for gathering voice commands and other audio input, distance sensors, motion, position, and/or orientation sensors that are configured to gather information on motion, position, and/or orientation (e.g., accelerometers, gyroscopes, compasses, and/or inertial measurement units that include all of these sensors or a subset of one or two of these sensors), sensors such as buttons that detect button press input, joysticks with sensors that detect joystick movement, keyboards, and/or other sensors. Each device10may omit some or all of devices18or may include one or more of devices18. Input-output devices18may also include wireless communications circuitry such as radio-frequency (RF) communications circuitry and near-field communications (NFC) circuitry. Data conveyed using these NFC components may be considered out-of-band signals and may be radiated using a separate NFC antenna within each device. NFC circuitry may include circuitry that operates as an NFC reader (sometimes referred to as a proximity coupling device or PCD) and/or as an NFC tag (sometimes referred to as a proximity inductive coupling card or PICC). An NFC tag may be active or passive. An active NFC tag can actively transmit a signal to the NFC reader, whereas a passive NFC tag modulates the carrier waveform transmitted by the NFC reader. Exemplary NFC communications operate at 13.56 MHz. In some embodiments, NFC communications may employ millimeter/centimeter wave technologies at 10 GHz or above (to about 300 GHz). Devices10in system8have alignment magnets20to facilitate magnetic attachment and alignment of a pair of devices10to each other. For example, each device10may have magnets20that help align that device10to another device so that the coils in each respective device overlap and are positioned for wireless power transfer. The use of magnets20for coil alignment allows power to be transferred satisfactorily between devices10. As shown inFIG.2, wireless power circuitry16may include wireless power coils36coupled to corresponding power and communications circuitry26. There may be one or more coils36in each device10. For example, devices10may each include a single coil and/or one or more devices10in system8may include multiple coils36. In arrangements in which devices10have more than one coil36, coils36may be arranged in a two-dimensional array (e.g., a two-dimensional array of overlapping coils that cover a charging surface) and/or may be stacked on top of each other (e.g., to allow wireless signals to be transmitted and/or received on opposing sides of a device). To facilitate transmission of wireless power between a first device and a second device, the coils of the first and second devices may be placed adjacent to each other (e.g., a coil in the first device may overlap and be aligned with a corresponding coil in a second device). Power and communications circuitry26may include inverters28and rectifiers30. Circuitry26may also include communications circuitry such as transmitters32and receivers34. When it is desired to transmit power wirelessly, the inverter28in a transmitting device may provide alternating-current signals (currents) to a corresponding coil36in the transmitting device. These alternating-current signals may have frequencies of 50 kHz to 1 MHz, 100-250 kHz at least 100 kHz, less than 500 kHz, or other suitable frequency. As alternating-current signals flow through the coil36in the transmitting device, alternating-current electromagnetic signals (e.g., magnetic field or magnetic flux signals) are generated and are received by an adjacent coil36in a receiving device. This induces alternating-current signals (currents) in the coil36of the receiving device that are rectified into direct-current power by a corresponding rectifier30in the receiving device. Rectifier30can provide the direct-current power to a load (e.g., a battery) or other electronic components within device10. In arrangements in which devices10have both inverters and rectifiers, bidirectional power transfer is possible. Each device can transmit power using its inverter28or may receive power using its rectifier30. Transmitters32and receivers34may be used for wireless communications. In some embodiments, out-of-band communications (e.g., Bluetooth® communications and/or other wireless communications using radio-frequency antennas in one or more radio-frequency communications bands may be supported). In other embodiments, coils36may be used to transmit and/or receive in-band communications data. Any suitable modulation scheme may be used to support in-band communications, including analog modulation, frequency-shift keying (FSK), amplitude-shift keying (ASK), and/or phase-shift keying (PSK). In an illustrative embodiment, FSK communications and ASK communications are used in transmitting in-band communications traffic between devices10in system8. A wireless power transmitting device may, as an example, use its transmitter32to impose frequency shifts onto the alternating-current signals being supplied by its inverter28to its coil36during wireless power transfer operations and a wireless power receiving device may use its coil36and its receiver34to receive these FSK signals. The receiving device in this scenario may use its transmitter32to modulate the impedance of its coil36, thereby creating corresponding changes in the current flowing through the wireless power transmitting device coil that are detected and demodulated using the receiver34in the wireless power transmitting device. In this way, the transmitter32in the wireless power receiving device can use ASK communications to transmit in-band data to the receiver34in the wireless power transmitting device while wireless power is being conveyed from the wireless power transmitting device to the wireless power receiving device. In some embodiments, some devices10have both transmitters32and receivers34and other devices10have only transmitters32or have only receivers34. It is desirable for devices10to be able to communicate information such as received power, battery states of charge, power measurements, and so forth, to control wireless power transfer. The present technology contemplates avoidance of the transmission of personally identifiable information in order to provide wireless power transfer functions. Out of an abundance of caution, it is noted that to the extent that any implementation of this charging technology involves the use of personally identifiable information, for example during authentication, that implementers should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. To ensure satisfactory wireless power transfer and in-band communications, devices10may have alignment magnets20. The housings of devices10may be formed from metal, polymer, glass, and/or other materials through which direct-current magnetic fields from permanent magnets such as alignment magnets20may pass. Alignment magnets20can be used to help ensure alignment between coils36in paired (mated) devices. Magnets20may have ring shapes, or other suitable shapes, and may each include one more permanent magnet elements with magnetic pole pairs in locations that facilitate alignment and attachment of devices10to each other. As an example, magnets20may be configured so that when the magnet20in a first device is magnetically attached to a corresponding magnet20in a second device, coil36of the first device will be overlapped by and aligned with coil36of the second device. It may sometimes be desired to transfer power between two devices of the same type (e.g., first and second cellular telephones of the same model). Each device may have a coil mounted within the housing of the device. The coil may be mounted adjacent to the rear wall (back wall) of the housing and may be configured to transmit and receive wireless signals through the rear wall. The rear wall may, in an illustrative arrangement, be formed from a dielectric such as glass or polymer. When it is desired to transfer power between first and second devices, the second device may be placed on top of the first device in a back-to-back arrangement of the type shown inFIG.3. As shown in the example ofFIG.3, first electronic device10A has a front face (front) FA and an opposing rear face (rear or back) RA. Second electronic device10B, which is resting on top of first device10A in the orientation ofFIG.2, has a front face (front) FB and has an opposing rear face (rear or back) RB. Devices10A and10B each has a display at its front face. When placed back-to-back to align the respective coils of devices10A and10B, rear faces RA and RB face each other as shown inFIG.3. Rear faces RA and RB may, for example, contact each other when devices10A and10B are mated. FIG.4Ais a top (front) view of electronic device alignment magnet20viewed from the front face of a device. As shown inFIG.4A, magnet20has one or more permanent magnet elements20C whose magnetic pole pairs are oriented in the X-Y plane such that magnetic poles common to each element are located in concentric inner and outer ring areas with opposite magnetic poles, where the inner ring area IR has a first magnetic polarity (south in the example ofFIG.4A) and the outer ring area OR has a second magnetic polarity (north in the example ofFIG.4A). The designations of N (to represent north poles) and S (to represent south poles) inFIGS.4A and4Band the other drawings are illustrative. It will be appreciated that throughout this description these designations can be reversed with no loss of generality (e.g., in any given embodiment S can be swapped for N and vice versa). This alignment magnet polarity pattern allows a device containing magnet20to magnetically attach to another device having a corresponding ring-shaped alignment magnet20′ with poles of opposite polarity (see, e.g., magnet20′ ofFIG.5A, in which inner and outer sets of vertical magnets are arranged in concentric circles so that inner ring area IR has an exposed pole of north polarity and outer ring area OR has an exposed pole of south polarity). Magnet20configured in this way is sometimes referred to as a ring-shaped magnet array. FIG.4Bis a cross-sectional side view of magnet20ofFIG.4Ataken along line42ofFIG.4Aand viewed in direction44. As shown inFIG.4B, magnets20produce a magnetic flux that is illustrated by magnetic field lines45originating from the north (N) pole to the south (S) pole. Magnetic field lines45emanating from the north pole may bend upward (or downward) in the Z direction and extend radially towards the center40of magnet20before bending downward (or upward) to terminate at the south pole. FIG.5Ais a top (front) view of an alignment magnet20′ in a wireless charging puck. As shown inFIG.5A, magnet20′ has concentric inner and outer magnet ring areas with opposite magnetic poles, where the inner ring area IR has a first magnetic polarity (north in the example ofFIG.5A) and the outer ring area OR has a second magnetic polarity (south in the example ofFIG.5A). This alignment magnet polarity pattern allows a device containing magnet20′ to magnetically attach to another device having a corresponding ring-shaped alignment magnet20of the type shown inFIGS.4A and4B. FIG.5Bis a cross-sectional side view of magnets20′ ofFIG.5Ataken along line46ofFIG.5Aand viewed in direction48. As shown inFIG.5B, magnet20′ of the charging puck may have one or more permanent magnet elements20C that each consist of two vertically oriented (i.e. in the z-axis) magnet pole pairs that may exist in one homogeneous material or as two separate materials mounted together, each pole pair having a first pole stacked vertically (in the z-axis) on top of a second opposite pole such that the poles located at the uppermost surface in the z-axis (i.e. most positive z-axis value) are common to each permanent magnet element and determine the polarity of the corresponding outer ring area OR and inner ring area IR. The two vertically oriented magnet pole pairs in each magnet element20C can be separated by a non-magnetized zone51. This causes magnetic flux from magnets20′ to be oriented vertically at the uppermost surface in the z-axis (i.e. most positive z-axis value). Ferrite50helps confine magnetic flux at the bottoms of magnets20′ and may be composed of any magnetically soft material such as iron or an alloy of iron. Although the arrangement ofFIGS.4A,4B,5A, and5Ballows an electronic device having magnet20to mate with a charging puck having magnet20′, first and second electronic devices with magnets20of the type shown inFIGS.4A and4Bcannot mate with each other, because when the first and second electronic devices are placed back to back in an attempt to align magnets20, the outer ring area OR consisting of north poles of the first electronic device will repel the corresponding outer ring area OR of north poles of the second electronic device. The south poles of the first and second devices will also repel each other when overlapping. As a result, two devices having identical magnets20may not be properly aligned for wireless charging between peer devices. Turning toFIG.6A, devices10of system8may overcome this challenge by inserting a device with a soft magnetic ring between two devices having magnets20that would otherwise repel each other when placed in the back-to-back configuration. As shown inFIG.6A, a first electronic device10A may be oriented face down, a second electronic device10B (i.e., an electronic device of the same type or model as device10A) may be oriented face up, and a third device10C may be interposed between devices10A and10B oriented in a back-to-back configuration. Devices10A and10B may each include a wireless power coil36(sometimes referred to as a wireless charging coil), a near-field communications (NFC) antenna60surrounding the wireless charging coil36, and magnet20(see, e.g., magnet20of the type shown inFIGS.4A and4B) surrounding the near-field communications antenna60. Coil36, NFC antenna60, and magnet20may be concentric annular (ring-like) structures. NFC antenna60may be used to transmit and/or receive out-of-band information between devices10. The example ofFIG.6Ain which NFC antenna60is disposed between coil36and magnet20within devices10A and10B is merely illustrative. As another example, the position of magnet20and NFC antenna60can be swapped such that magnet20is interposed between coil36and antenna60. As another example, the position of coil36and NFC antenna60can be swapped such that coil36is interposed between antenna60and magnet20. As another example, coil36may surround magnet20while the NFC antenna60surrounds coil36such that magnet20runs along an inner peripheral edge of coil36. As another example, the position of coil36and magnet20can be swapped such that coil36runs along an outer peripheral edge of NFC antenna60. As yet another example, magnet20may surround NFC antenna60while coil36surrounds magnet20such that magnet20is interposed between an outer peripheral edge of NFC antenna60and an inner peripheral edge of coil36. If desired, other non-concentric arrangements can also be used. Device10C may be a removable battery case (sometimes referred to as an external accessory or accessory device). Device10C has a housing with a recess R and/or other structures configured to receive device10B. In this way, a user may removably attach device10B to device10C so that devices10B and10C may be used together as a portable unit. Device10C may provide supplemental power to device10B while protecting device10B from damage due to stress-producing events such as drop events when device10B is installed on device10C. This example in which device10C has a protruding lip portion68shaped to receive the rear face of device10B is merely illustrative. In other embodiments, device10C may lack protruding portion68and may magnetically attach to device10B using soft magnetic ring70. Device10C may include two wireless power coils such as coils62and64. During a bypass mode of operation, coils62and64are shorted together. Electrical components such as battery66may be interposed between coils62and64. The shorting of coils62and64allows internal device components such as battery18to be effectively bypassed when wireless power is being conveyed between devices10A and10B. Devices10A and10B may transmit power and/or may receive wireless power (e.g., devices10A and10B may support bidirectional charging when placed in the back-to-back configuration). As an example, during a first wireless charging mode when device10A is transmitting wireless power to device10B, alternating current electromagnetic signals that are transmitted by coil36in device10A are received by coil62. Since coil64is shorted to coil62in this mode of operation, coil64emits electromagnetic signals that are received by coil36in device10B. As another example, during a second wireless charging mode when device10B is transmitting wireless power to device10A, alternating current electromagnetic signals that are transmitted by coil36in device10B are received by coil64. Since coil64is shorted to coil62in this mode of operation, coil62emits electromagnetic signals that are received by coil36in device10A. Device10C may include a near-field communications (NFC) antenna60surrounding coils62and64. NFC antenna60may be used to convey information about device10C to device10B and/or device10A. For example, antenna60may be configured to convey a device type (e.g., whether device10C is a removable case or a wireless charging puck, etc.), a physical characteristic of the device such as the actual color of the device, a function of the device, or other information associated with that device. In accordance with an embodiment, device10C may further include a ring of soft magnetic material (see, e.g., ring70) surrounding NFC antenna60. Ring70may be formed from “soft” magnetic material(s), which are defined as magnetic materials that are easily magnetized and demagnetized. Unlike “hard” (permanent) magnets, which retain their magnetism and have poles that can attract opposite polarities and repel like polarities, soft magnetic materials only become magnetized (i.e. have a magnetic flux) when an external magnetic field is applied but do not retain their magnetism when the external magnetic field is removed. Ring70(sometimes referred to as a soft magnetic ring or a ring-like soft magnetic structure) is not a permanent magnet per se and does not have static poles, so it will not repel other magnets. Soft magnetic materials are characterized by a high relative permeability (e.g., a relative permeability of at least 500, 500-1000, at least 1000, at least 10,000 or at least 100,000 or more), which measures how readily a material conducts magnetic flux due to an applied magnetic field. Ring70should also be formed from soft magnetic material with sufficient saturation flux density (e.g., a saturation flux density of at least 0.5 T, 0.5-1 T, 1-2 T, or more than 2 T), which measures the point at which the magnetic material cannot contain any more magnetic flux. As examples, ring70may be formed from soft magnetic materials such as soft ferromagnetic (iron-based metal alloy) and/or soft ferrimagnetic (iron-based ceramic) materials, which may include pure iron annealed in hydrogen (which has a relative permeability of 200,000 and a saturation flux density of 2 T), pure iron without annealing (which has a relative permeability of 5,000 and a saturation flux density of 2.2 T), nickel (which has a relative permeability of 100-600 and a saturation flux density that is greater than ceramic ferrites), cobalt (which has a relative permeability of 18,000 and a saturation flux density of 1.2-1.8 T), nickel-plated steel, soft ferrite, steel, silicon steel (e.g., an iron alloy with 3-4% silicon), low carbon steel (e.g., an iron alloy with 0.2-0.4% carbon with a relatively permeability of 1000-3000 and a saturation density of 2.2 T), soft nanocrystalline ferrite material (which has a relative permeability of 10,000-100,000 or more and a saturation flux density of 1-2 T), Mu-metal ferromagnetic alloy (which has a relative permeability of 300,000-400,000 and a saturation flux density of 0.8-1.6 T), permalloy ferromagnetic alloy (which has a relative permeability of 10,000-100,000 or more and a saturation flux density of 0.6-1.2 T), some combination of these materials, and/or other suitable soft magnetic material with high relatively permeability and high saturation flux density. Ring70formed using soft magnetic material(s) with high relative permeability and high saturation flux density enables ring70to block and short out (shunt) magnetic flux emanating from nearby magnets while providing magnetic/mechanical attraction forces between ring70and the nearby magnets.FIG.6Bis a cross-sectional side view showing how soft magnetic ring70in device10C is used to shunt magnetic flux from magnets20within electronic devices10A and10B when placed in the back-to-back configuration. Operated in this way, the wireless charging coil in device10A will be properly aligned with the wireless charging coil in device10B. Soft magnetic ring70may therefore sometimes be referred to as a magnetic flux shunting (shorting) structure or a magnetic field shunting (shorting) structure. As shown inFIG.6B, magnetic fields72from magnet20in device10A will be shorted (shunted) by soft magnetic ring70(e.g., magnetic field line72originating from the north pole of magnet20travels upward towards an outer peripheral edge of ring70, travels along the width of ring70towards the center of the device before exiting an inner peripheral edge of ring70, and then travels downward towards the south pole of magnet20). Similarly, magnetic fields72′ from magnet20in device10B will also be shorted (shunted) by soft magnetic ring70(e.g., magnetic field line72′ originating from the north pole of magnet20travels downward towards an outer peripheral edge of ring70, travels along the width of ring70towards the center of the device before exiting an inner peripheral edge of ring70, and then travels upwards toward the south pole of magnet20). If ring70had not been interposed between magnets20, the magnetic field72A emanating from magnet20in device10A would repel the magnetic field72B emanating from magnet20in device10B, which would cause devices10A and10B to be misaligned. Ring70has a thickness T. Ring70that is thicker can hold more magnetic flux and is thus better at shielding and shunting magnetic fields from nearby magnets. Thickness T may, for example, be at least 0.5 mm, less than 0.5 mm, 0.5-1 mm, or greater than 1 mm. FIG.6Cis a top (front) view showing wireless charging coil64, NFC antenna60, and soft magnetic ring70in an illustrative device10C. Coil64may be ring-shaped (sometimes referred to as an annular coil or circular coil) and may have a central opening with one or more magnetic cores optionally formed in the central opening. Ring-shaped NFC antenna60may laterally surround coil64. NFC antenna60may sometimes be described as annular or circular. Soft magnetic ring70may laterally surround NFC antenna60. Ring70may also sometimes be described as annular or circular. InFIG.6C, coil64, antenna60, and soft magnetic ring70are concentric (e.g., each structure64,60, and70has a center coinciding at point C). Antenna60runs along a peripheral (outer) edge of wireless charging coil64. Ring70runs along a peripheral (outer) edge of NFC antenna60. Ring70may have a width W that is similar to the width of magnets20within devices10A and10B. The example ofFIG.6Cin which NFC antenna60is disposed between coil64and ring70within device10C is merely illustrative. As another example, the position of ring70and NFC antenna60can be swapped such that ring70is interposed between coil64and antenna60. As another example, the position of coil64and NFC antenna60can be swapped such that coil64is interposed between antenna60and ring70. As another example, coil64may surround ring70while the NFC antenna60surrounds coil64such that ring70runs along an inner peripheral edge of coil64. As another example, the position of coil36and magnet20can be swapped such that coil36runs along an outer peripheral edge of NFC antenna60. As yet another example, ring70may surround NFC antenna60while coil64surrounds ring70such that ring70is interposed between an outer peripheral edge of NFC antenna60and an inner peripheral edge of coil64. If desired, other non-concentric arrangements can also be used. In other suitable embodiments, the wireless charging coil, NFC antenna structure, and the soft magnetic flux shunting ring structure may be oval, triangular, rectangular, pentagonal, hexagonal, octagonal, or have another polygonal footprint. The example ofFIGS.6A-6Cin which a removable battery case10B is interposed between devices10A and10B to prevent magnets20from repelling one another is merely illustrative. In accordance with another embodiment, a device such as accessory10D can also include a soft magnetic ring70surrounding an NFC antenna60. Accessory10D may be a removable case that does not include any wireless charging coil or battery. Device10D has a housing with a recess R and/or other structures configured to receive an electronic device10. A user may removably attach a device10to accessory10D so that devices10and10D are used together as a portable unit. This example in which device10D has a protruding lip portion69shaped to receive the rear face of a device10is merely illustrative. In other embodiments, device10D may lack protruding portion69and may magnetically attach to device10using soft magnetic ring70. A device10that is attached to accessory10D having ring70can be mated with another device10in a back-to-back configuration to perform bidirectional wireless charging operations. FIG.8is a cross-sectional side view showing device10B attached to an accessory (e.g., accessory10C of the type shown inFIG.6Aor accessory10D of the type shown inFIG.7) to form a portable unit, which is placed on device10E (e.g., a wireless charging puck or mat). Device10B may include magnet20of the type described in connection withFIGS.4A and4B, which has an outer ring area OR with north polarity and an inner ring area IR with south polarity. Device10E may include magnet20′ of the type described in connection withFIGS.5A and5B, which has an outer ring area OR with an exposed pole of south polarity and an inner ring area IR with an exposed pole of north polarity. The accessory (e.g., device10C or10D) stacked between devices10B and10E includes ring70formed using soft magnetic material(s) with high relative permeability and high saturation flux density, which enables ring70to block and short out (shunt) magnetic flux emanating from magnets20and20′ while providing magnetic/mechanical attraction forces between ring70and magnets20and20′. As shown inFIG.8, ring70in the interposing accessory device is used to shunt magnetic flux from magnet20within device10B and from magnet20′ within device10E. Operated in this way, the wireless charging coil in device10B will be properly aligned with the wireless charging coil in device10E so that device10E can transmit wireless power to device10B with optimal efficiency. Soft magnetic ring70may therefore sometimes be referred to as a magnetic flux shunting (shorting) structure or a magnetic field shunting (shorting) structure. Magnetic fields74from magnet20in device10B will be shorted (shunted) by soft magnetic ring70(e.g., magnetic field line74originating from the north pole of magnet20travels downward towards an outer peripheral edge of ring70, travels along the width of ring70towards the center of the accessory before exiting an inner peripheral edge of ring70, and then travels upward towards the south pole of magnet20). Similarly, magnetic fields76from magnet20′ in device10E will also be shorted (shunted) by soft magnetic ring70(e.g., magnetic field line76originating from the exposed north pole of magnet20′ travels upward towards the inner peripheral edge of ring70, travels along the width of ring70away from the center of the accessory before exiting the outer peripheral edge of ring70, and then travels downwards toward the exposed south pole of magnet20′). The embodiments ofFIG.6-8in which soft magnetic ring70is formed within an accessory that can be interposed between two devices10that each include a permanent (hard) magnet is merely illustrative.FIG.9shows another suitable embodiment in which devices10A and10B (e.g., cellular telephones of the same type or model) each include a soft magnetic ring70instead of magnet20of the type shown inFIGS.4A and4Band are stacked in a back-to-back configuration. As shown inFIG.9, device10A has a rear face RA facing the rear face RB of device10B. Similar to ring70described in connection withFIGS.6-8, rings70within devices10A and10B are formed from soft magnetic materials characterized by a high relative permeability (e.g., a relative permeability of 500 or more, 500-1000, more than 1000, more than 10,000, or more than 100,000) and high saturation flux density (e.g., a saturation flux density of at least 0.5 T, 0.5-1 T, 1-2 T, or more than 2 T). As examples, ring70may be formed from soft ferromagnetic and/or soft ferrimagnetic materials, which may include pure iron annealed in hydrogen, pure iron without annealing, nickel, cobalt, nickel-plated steel, soft ferrite, steel, silicon steel (e.g., an iron alloy with 3-4% silicon), low carbon steel (e.g., an iron alloy with 0.2-0.4% carbon, soft nanocrystalline material, mu-metal, permalloy, some combination of these materials, and/or other suitable soft magnetic material with high relatively permeability and high saturation flux density. Since ring70of device10A and ring70of device10B are both soft magnetic structures that do not retain any magnetism in the absence of applied magnetic fields from a DC magnet, rings70will not repel each other when devices10A and10B are stacked in the back-to-back configuration. Since rings70are demagnetized in this state, there will be no magnetic attraction forces between devices10A and10B, and the user will need to manually align devices10A and10B to ensure that the wireless charging coils36are aligned for optimal wireless power transfer. Wireless charging coil36, NFC antenna60, and soft magnetic ring70within each of devices10A and10B may be concentric (annular) structures. The example ofFIG.9in which NFC antenna60is disposed between coil36and ring70within devices10A and10B is merely illustrative. As another example, the position of ring70and NFC antenna60can be swapped such that ring70is interposed between coil36and antenna60. As another example, the position of coil36and NFC antenna60can be swapped such that coil36is interposed between antenna60and ring70. As another example, coil36may surround ring70while the NFC antenna60surrounds coil36such that ring70runs along an inner peripheral edge of coil36. As another example, the position of coil36and ring70can be swapped such that coil36runs along an outer peripheral edge of NFC antenna60. As yet another example, ring70may surround NFC antenna60while coil36surrounds ring70such that ring70is interposed between an outer peripheral edge of NFC antenna60and an inner peripheral edge of coil36. If desired, other non-concentric arrangements can also be used. In other suitable embodiments, coil36, NFC antenna60, and ring70may be oval, triangular, rectangular, pentagonal, hexagonal, octagonal, or have another polygonal footprint. Device10B with a soft magnetic ring70is compatible with power transmitting devices or even accessories with magnets.FIG.10Ashows device10B (e.g., a cellular telephone) with a soft magnetic ring70mounted on device10E (e.g., a wireless charging puck). As shown inFIG.10A, device10B has a rear face RB that is placed on the top charging surface of device10E. Device10E includes magnet20′ (see, e.g., magnet20′ of the type described in connection withFIGS.5A and5B). When device10B is mounted on top of device10E, magnet20′ will emit magnetic flux that magnetizes ring70. As a result, ring70will be magnetically attracted to magnet20′ to align wireless charging coils36of devices10E and10B while power transmitting device10E is conveying wireless power to power receiving device10B. FIG.10Bis a cross-sectional side view showing how soft magnetic ring70in device10B is used to shunt magnetic flux from magnet20′ within electronic device10E when device10B is mounted on top of device10E. Operated in this way, the wireless charging coil in device10B will be properly aligned with the wireless charging coil in device10E during wireless charging operations. As shown inFIG.10B, magnetic fields78from magnet20′ will be shorted (shunted) by soft magnetic ring70(e.g., magnetic field line78originating from the exposed north pole of magnet20′ travels upward towards an inner peripheral edge of ring70, travels along the width of ring70away from the center of device10B before exiting an outer peripheral edge of ring70, and then travels downward towards the exposed south pole of magnet20′). In general, soft magnetic ring70may be incorporated into any device with a wireless charging coil, any device with a battery, or any accessory with or without a battery so that ring70can be used to shunt magnetic flux from a nearby magnet while providing magnetic attraction forces to properly aligned two mating devices or accessories. The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination. | 40,903 |
11862986 | DETAILED DESCRIPTION Before explaining one or more embodiments of the disclosure in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description or illustrated in the drawings. In the following detailed description of embodiments, numerous specific details may be set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art having the benefit of the instant disclosure that the embodiments disclosed herein may be practiced without some of these specific details. In other instances, well-known features may not be described in detail to avoid unnecessarily complicating the instant disclosure. As used herein a letter following a reference numeral is intended to reference an embodiment of the feature or element that may be similar, but not necessarily identical, to a previously described element or feature bearing the same reference numeral (e.g., 1, 1a, 1b). Such shorthand notations are used for purposes of convenience only and should not be construed to limit the disclosure in any way unless expressly stated to the contrary. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). In addition, use of “a” or “an” may be employed to describe elements and components of embodiments disclosed herein. This is done merely for convenience and “a” and “an” are intended to include “one” or “at least one,” and the singular also includes the plural unless it is obvious that it is meant otherwise. It is to be understood that depicted architectures are merely exemplary and that many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality, common goal, objective, and/or result is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality, common goal, objective, and/or result is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “connected,” or “coupled,” to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being “couplable,” to each other to achieve the desired functionality (e.g., “operatively coupled” or “electrically coupled”) Additionally, unless otherwise indicated, a description indicating that one component is “connected to” another component or “between” two components indicates that such components are functionally connected and does not necessarily indicate that such components are physically in contact. Rather, such components may be in physical contact or may alternatively include intervening elements. Similarly, descriptions that a particular component is “fabricated over” another component (alternatively “located on,” “disposed on,” or the like) indicates a relative position of such components but does not necessarily indicate that such components are physically in contact. Such components may be in physical contact or may alternatively include intervening elements. Finally, as used herein any reference to “one embodiment” or “some embodiments” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment disclosed herein. The appearances of the phrase “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment, and embodiments may include one or more of the features expressly described or inherently present herein, or any combination of sub-combination of two or more such features, along with any other features which may not necessarily be expressly described or inherently present in the instant disclosure. A wireless power transfer (WPT) receiving circuit is disclosed. The WPT receiving circuit includes wireless power receiving circuitry (e.g., coils), rectifying circuitry, and field effect transistor (FET)-containing circuitry that can effectively buck the voltage of an incoming power signal. The FET-containing circuitry allows the WPT receiving circuit to reduce incoming voltage under overvoltage conditions without shutting down the charging process, and without interrupting communication between the charging device and the device to be charged. In particular, the bucking process is accomplished by dynamically changing the impedance of an input via the FET. FIG.1is a block diagram of an environment90for a user device100(e.g., first apparatus), in accordance with one or more embodiments of the disclosure. The user device100may be configured as any type of electrically powered device. For example, the user device100may be configured as a mobile communication device including but not limited to a smart phone, cell phone, or tablet. In another example, the user device100may be configured as a media device (e.g., media playing and/or recording device). For instance, the user device100may include an audio device such as an audio recorder, an audio converter, an audio player, or a speaker (e.g., a Bluetooth-enabled speaker). In another instance, the user device100may include a video device such as a video display, a video recorder, a camera, or other video device. In another example, the user device100may be configured as, a driver assistance module in a vehicle, an emergency transponder, a pager, a watch, a satellite television receiver, a stereo receiver, a computer system, music player, laptop or tablet computer, home appliance, or virtually any other device. In another example, the user device100may be configured as a computer (e.g., a laptop computer). In another example, the user device100may be configured as a computing/entertainment device for a vehicle. The user device100may communicate with a network controller, such as an enhanced Node B (eNB) or other base station. For example, the network controller may establish communication channels such as a control channel and a data channel, and exchange data via these channels. The user device100may be exposed to many other sources of wireless signals as well, (e.g., from a wireless charging pad), and wireless signals may be harvested in conjunction with the WPT and techniques described below. The user device100may also support one or more Subscriber Identity Modules (SIMs). The user device100may include a user interface102and a rechargeable battery104that powers electronic componentry within the user device100. The battery104is configured to be charged via a wireless charger108(e.g., a second apparatus). For example, the wireless charger108may be plugged into a power receptacle112, wherein electrical power is received by power receiving circuitry116within the wireless charger108, and outputted as a wireless power signal120via a wireless power transmitter124. The wireless power transmitter124includes at least one wire coil, and transmits the wireless power signal120by magnetic fields using inductive coupling to a receiving coil on a wireless power receiver128(e.g., a first receiver) of the user device100. Once received, the power received from the wireless power signal120may be referred to herein as a wireless power input. The wireless power input received by the wireless power receiver128is then rectified to an electrical current (e.g., a DC current) by rectifying circuitry132as required by the user device100and/or battery104, with a portion of the power used to charge the battery104. In general, rectification is the conversion of an AC current, which periodically reverses direction, to a DC current, which flows in only one direction. In a general example, a rectifier may receive an input of an AC current at 120 volts from an electrical outlet, and rectify the AC current to produce an output DC current at 5 volts. In another general example, a rectifying circuit may receive an AC input current at 5 volts to produce an output DC current at 5 volts. As described herein the rectification of the input AC current may be either a rectification of a directly received AC input (e.g., from an AC source), or may be a rectification of an indirectly receive AC input that has been modified (e.g., a signal based on the AC input). For example, componentry within the user device100may modify the AC input from the power receiving circuitry116, with then modified AC input, or signal, then rectified by the rectifying circuitry132. Power reception and modulation by the wireless power receiver128and the rectifying circuitry132are controlled by rectifier control circuitry136(e.g., a first controller). The rectifier control circuitry136performs the processive functions required for wireless power reception and battery charging. The user device100may utilize power directly from the wireless charger108or the battery104for operation. The user device100further includes a system controller140that includes one or more processors144, memory148, and a communication interface152. The one or more processors144may include any processor or processing element known in the art. For the purposes of the present disclosure, the term “processor” or “processing element” may be broadly defined to encompass any device having one or more processing or logic elements (e.g., one or more micro-processor devices, one or more application specific integrated circuit (ASIC) devices, one or more field programmable gate arrays (FPGAs), one or more digital signal processors (DSPs), or a state device). In this sense, the one or more processors144may include any device configured to execute algorithms and/or instructions (e.g., program instructions stored in memory148). The memory148may include any storage medium known in the art suitable for storing the one or more sets of program instructions executable by the associated one or more processors144. For example, the memory148may include a non-transitory memory medium. For instance, the memory148may include, but is not limited to, a read-only memory (ROM), a random-access memory (RAM), a magnetic or optical memory device (e.g., disk), a magnetic tape, a solid-state drive, and the like. The memory148may be configured to provide information to the system controller140, or other components of the user device100. In addition, the memory148may be configured to store user input. The memory148may be housed in a common controller housing with the one or more processors144. The memory148may, alternatively or in addition, be located remotely with respect to the spatial location of the processors144, or the system controller140. For example, the one or more processors144and/or the system controller140may access a remote memory148accessible through a network (e.g., wireless, and the like) via one or more communication interfaces152. The one or more communication interfaces152may be operatively configured to communicate with components of the system controller140or any other componentry within the user device100. For example, the one or more communication interfaces152may be configured to retrieve data from the one or more processors144or other devices, transmit data for storage in the memory148, retrieve data from storage in the memory148, and so forth. The one or more communication interfaces152may also be communicatively coupled with the one or more processors144to facilitate data transfer between components of the system controller140, and the user device100, including the rectifying circuitry13and/or rectifier control circuitry136. It should be noted that while the one or more communication interfaces152are described as a component of the system controller140, one or more components of the one or more communication interfaces152may be implemented as external components communicatively coupled to the system controller140via a wired and/or wireless connection. It should also be noted that the rectifier control circuitry136may also include one or more processors114, memory,148, and communication interfaces152to perform the functions described herein. In embodiments, the user device is configured to communicate unidirectionally and/or bidirectionally with the wireless charger108via a wireless communication signal156(e.g., controlled by the system controller140or the rectifier control circuitry136). The wireless communication signal156may be communicated (e.g., transmitted) via induction of the coils of the wireless charger108and/or the user device100, or through other wireless signaling methods including but not limited to Bluetooth, WIFI, and ZigBee. Communication from the user device100to the wireless charger108creates a feedback loop wherein the user device100can transmit to the wireless charger108an instruction to change the current state of the wireless power transmitter124(e.g., to reduce the wireless power signal120due to an overvoltage). For example, the wireless power receiver128may be configured to transmit a signal (e.g., an amplitude shift keying (ASK) signal, a frequency shift keying (FSK) signal, or other modulation-based signal) to the wireless power transmitter124, and the wireless power transmitter may be configured to receive and process the signal. The wireless power receiver128may also configured to receive and process a communication signal (e.g., ASK, FSK, or another modulated signal). FIG.2Ais a circuit diagram illustrating a rectifier circuit200(e.g., a first circuit), in accordance with one or more embodiments of the disclosure. The rectifier circuit200may include some or all componentry of the wireless power receiver128, the rectifying circuitry132, and the rectifier control circuitry136. The rectifier circuit200may harvest wireless power from any wireless power source. For example, the rectifier circuit200may harvest 6.78 MHz Alliance for Wireless Power (A4WP, also referred to as AirFuel) power transmissions. The rectifier circuit200facilitates efficiency improvements in receiving the transmitted energy and delivering it (e.g., as the rectified Direct Current (DC) voltage Vrect) to subsequent energy consuming stages in the device, such as to the battery104via Vout204. Wireless power transmission suffers from efficiency losses at several stages, such as from converting a power source into a radio frequency (RF) wireless power signal transmission, receiving the RF flux of the wireless power signal120, and converting the RF flux into a usable DC voltage in the receiving device. The wireless power receiver128may employ magnetic resonance achieved through matching the inductance and capacitance to the transmitter system to obtain a high Q receiver that is very responsive to a fundamental frequency (e.g., 6.78 MHz) of the wireless power signal120. In that regard, the inductance may be provided by a receiving coil208that receives the flux of the wireless power signal. The inductance may also be, for example, one or more turns of a conductor on a printed circuit board, or another type of antenna. The inductance202produces an Alternating Current (AC) current and a first capacitor212may be tuned with respect to the receiving coil208to achieve the resonance that results in substantial responsiveness to the wireless power signal120. The wireless power receiver128provides the AC current into the rectifier circuit200via the AC positive conductor216and the AC negative conductor220(e.g., collectively referred to as a first conductor224). The rectifier circuit200rectifies the AC current into a DC voltage, Vrect. Vrect may provide energy for any subsequent processing circuitry. In one implementation, the rectifier circuit200is wholly or partially integrated into an integrated circuit chip268. The integrated circuit chip268may also be referred to as a “device”. In other implementations, discrete components may be used. A switch network228receives power from the first conductor224and includes a plurality of switches (e.g., switches230,232,234, and236) arranged to rectify the wireless power input and generate a rectified voltage. The switches230-236may be Metal Oxide Semiconductor FETs (MOSFETs), for example, or other types of transistors or other types of switches. The rectifier control circuitry136is in communication with the switch network228. For example, the rectifier control circuitry136may control the ON and OFF states of the switches230-236to rectify the wireless power input using switching control outputs. The rectified wireless power input162, Vrect, once generated, comprises a full-wave rectified version of the wireless power input. The rectifier control circuitry136may include a processing unit (e.g., state machine240containing one or more processors144), an analog-digital converter (ADC242) and a control loop mechanism, such as a proportional-integral-derivative (PID) controller244(e.g., analog or digital). Other control loop mechanisms may be utilized. The state machine may include any finite state processor including but not limited to a central processing unit (CPU) or an application specific integrated circuit (ASIC). The rectifier circuit200further includes a plurality of pinouts246,248,250,252,254,256,258,260,262,264that may be accessible to the rectifier control circuitry136. For example, the rectifier control circuitry136may detect a state (e.g., current, voltage, oscillation) of power via one or more pinouts246-264and may be affect the state of the power (e.g., by injection) at one or more pinouts. For example, the rectifier control circuitry136may be in communication with the switch network228, controlling switches230,232to by delivering power at pinouts250,252, respectively (e.g., the power amplified via gate drivers266). The pinouts246-264may be arranged on the integrated circuit chip268, (represented by dotted square). The rectifier circuit may also include current sensing circuitry270and voltage regulating circuitry272. In embodiments, the rectifier circuit200further includes a bucking switch configured to control (e.g., buck) incoming voltage (e.g., incoming power from the coil208). For example, the switch may be configured as, or include, a first field effect transistor (e.g., a first FET274). The first FET274may be incorporated in one of several places within the rectifier circuit200. The first FET274may handle high power inputs that may be deleterious to the integrated circuit chip268and may therefore be disposed outside of the integrated circuit chip268(e.g., as an external FET274). For example, the first FET may be configured as an eternal FET that can effectively handle 115 volts or a maximum VDS of 117 volts. However, in some embodiments, the first FET274may be incorporated into the integrated circuit chip268. The first FET may be configured as an insulated gate FET (MOSFET), a junction FET (JET) or a metal-semiconductor FET (MESFET). In operating as a buck converter, the first FET274operates to facilitate a step down a voltage from the input (e.g., a portion of the wireless power input) to an output that is controlled by an input signal to the gate of the first FET274. Utilizing the first FET274, the rectifier circuit200can regulate output voltage continuously, or only when the voltage rises above a threshold limit (e.g., semi-continuously). In embodiments, the drain of the first FET274is coupled to the AC positive conductor216via a drain conductor276(e.g., the drain conductor276is configured as an electrically conductive element) and the source of the first FET274is coupled to the AC positive conductor216via a source conductor278(e.g., the source conductor278is configured as an electrically conductive element). A second capacitor280is disposed within the drain conductor276. This arrangement forms a FET loop282(e.g., the arrangement forms a first loop) with parallel capacitors (e.g., the first capacitor212and the second capacitor280). The gate of the first FET274is coupled to a pinout254that is accessible to the rectifier control circuitry136. In this arrangement, the first FET274/FET loop282acts as a dynamic capacitive switch to modulate the network reactance magnitude that is controllable by the control loop mechanism (e.g., PID controller244) and state machine240. For example, the PID controller244may receive a Vrect value and a Vrect threshold value, or predetermined Vrect threshold value (e.g., a Vrect threshold value set before instant operation of the rectifier circuit200, such as during construction/programming of the rectifier control circuitry136). If the Vrect value is above the predetermined Vrect threshold value, the PID controller244may transmit a pulse width modulation (PWM) instruction to the state machine240, which then applies a PWM signal (e.g., a gate input) to the first FET274via pinout254, The PWM signal may be synchronized with the power running through the AC positive conductor216(e.g., AC positive and/or AC negative waveforms) such that the first FET274is controlled by the PWM. For example, the state machine240may alter the period of the PWM signal or other PWM signal characteristic based on the power input received from the first conductor224, effectively synchronizing the PWM signal to the wireless power input. The ability of the first FET274to buck an input voltage is based on the ability of the first FET274to dynamically modulate an impedance that is generated by power flowing through the field coil208and the first capacitor212along the first conductor224to the switch network228(e.g., the first FET274receiving a portion of the AC input as a derived signal). For example, if the impedance of a signal along the first conductor224increases, the output signal, Vrect, drops for a given load, and the rectifier control circuitry136may then send a control signal to the gate of the first FET274to open or close the first FET274accordingly so that Vrectis retained at a normal level. Besides synchronizing the PWM signal to AC waveforms, other methods for controlling the first FET274are possible. For example, the first FET274may be controlled by hysteretic switching (e.g., with or without synchronization). For example, the rectifier circuit200may employ a hysteresis comparator to generate an input signal at the gate of the first FET274, wherein the hysteresis comparator compares Vrectto a threshold or reference voltage during operation. In another example, the rectifier circuit200may employ static control, where the first FET274is turned off when the input voltage is high, or near an overvoltage protection (OVP) threshold. The rectifier circuit200may then perform fine regulation using voltage collapse control or may dynamically adjust the load ballast to provide fine output voltage control. In another example, the signals to the gate of the first FET274may be controlled via a set/reset latch (e.g., an SR latch) or a hysteretic on/off control. In some embodiments, the rectifier control circuitry136controls the operation of the first FET274via the use of current limitation values (iLIM) (e.g., current thresholds, such as the rectifier turn-off threshold). Adjusting this threshold may control the rectifier input impedance. For example, when the threshold is negative current, the rectifier input capacitance increases. Controlling the input capacitance is one method to buck regulate as long as the coil network impedance is capacitive, which may be assured with switching via the first FET274. In another example, the PID controller244may provide an iLIMinput to the state machine240, wherein the state machine compares the iLIMto an average measured current iDC(e.g., subtracts the iDCfrom the iLM) to determine a set current limitation value iLIMthat is used to generate the gate input to the gate of the first FET274causing a negative phase shift, effectively regulating Vrect. The rectifier circuit200is able to use iLIMthresholds in bucking wed voltage because the rectifier circuit200is capacitive and the switch network228modulates the capacitance. For example, by using the state machine240, the input capacitance can be modulated using negative phase shifting (e.g., by using negative iLIMthresholds). However, the rectifier circuit200may also buck Vrectif the rectifier circuit200is inductive and the rectifier modulates the input inductance. For example, using a revised state machine240, the input inductance can be modulated using positive phase shifting (e.g., by using positive iLIMthresholds). The state machine240may also be able to buck Vrectif the rectifier circuit200includes true isolated switch functionality and the duty cycle throttles the current to Crect, or if the rectifier circuit200is detuned to control the total reactance in adjusting Vrect(e.g., the greater the reactance, the greater the voltage drop). The ability of an external first FET274to rectify an input voltage is shown in graphs288,290ofFIGS.2B-C, in accordance of one or more embodiments of the disclosure. Graph288illustrates a Vrect(e.g., in volts) over time (ms) plot created from plot data derived from testing of the rectifier circuit200ofFIG.2A(e.g., where PWM was synchronized with AC waveforms) and demonstrates that the buck switches in variable series capacitance using a PID control with PWM signaling to the first FET274. Graphed line292represents a normal system Vrectwithout any buck circuitry or control. The bump at 1 ms is a result of the test system operating through an ASK modulation load pulse. Graphed line293represents the buck system Vrectwhich is being controlled by the control voltage to the PID controller, represented by graphed line294. As shown, in graph188, the application of an overvoltage at time zero (e.g., 25 volts via the ramped control input) causes an immediate spike in the Vrectof the tested circuit (e.g., graphed line293). The rectifying circuit200prevents Vrectfrom reaching an over voltage state, plateauing at approximately 17 volts. When the test input is ramped downward to approximately 7.5 volts, the Vrectof the rectifying circuit200tracks to the ramped voltage. A similar result is seen in graph290ofFIG.2B, which uses plot data derived from testing of the rectifier circuit200wherein the PID controller244modulates the input capacitance using negative phase shifting (e.g., by using negative iLIMthresholds). Here, the external FET is statically turned on to ensure the network is capacitive and then the iLIMthresholds are adjusted to lower the voltage (e.g., changes to the iLIMthresholds adjust the rectifier input capacitance). Therefore, the external first FET274is capable of bucking an input voltage using different control signal schemes. Subcomponents or subcircuits of the rectifier circuit200may have more than one possible arrangement. For example, the rectifier circuit200may include one of two or more possible arrangements FET loop282a-bas shown inFIG.2D, in accordance with one or more embodiments of the disclosure. For instance, FET loop282a, similar to the FET loop282as shown inFIG.2Ais shown with the second capacitor280positioned in-line between the external first FET274and a junction296that leads to the field coil208and the AC positive conductor216. In another instance, the FET loop282bshows the second capacitor280positioned in line between the junction296and the field coil208. This second arrangement of the FET loop282bfor switching series capacitance demonstrates an improved, lower breakdown voltage than FET loop282b. In some embodiments, the First FET274may be disposed internally within the switch network228(e.g., an internal FET). For example, the first FET274may be coupled at the gate to the gate driver266and operably coupled at the source and drain to switches230,232, as shown inFIG.3A. In another example, the source and drain of the first FET274may be operably coupled to switches232,236, as shown inFIG.3B. Other configurations are possible. The placement of the first FET274within the switch network stops current conduction for part of the duty cycle during operation. The PID controller244may then send signals to regulate the duty cycle, which then is synchronized to the AC waveforms via the state machine240. The rectifier circuit200ofFIG.3Awas further tested for the ability of rectify a voltage, as shown in Graph302ofFIG.3C. Similar to the result of the testing of the rectifier circuit200in graphs288,290, graph302also shows the ability of the internal-FET274to rectify an over voltage, and maintain a steady-state Vrectvoltage of approximately 16 volts, with Vrectdecreasing as the ramped control input (e.g., line294) falls below 15 volts. During start-up, the rectifier circuit200requires a voltage to turn on the first FET274. In some embodiments, the first capacitor212carries enough current to support start-up conditions in order for the rectifier circuit200to get enough voltage to then turn on the first FET274. However, if the parallel capacitor is too large (e.g., has too high a capacitance), then a higher load on Vrectis needed to maintain buck regulation. If the load is too weak, then there may be difficulty in turning on the first FET274. However, there are several potential solutions for turning on the first FET274. For example, the rectifier circuit200may utilize a backup voltage system to turn on the first FET274, as shown inFIG.4A. For instance, the battery104may be electrically couplable to a battery input400and supply a battery voltage (vbat402) that provides a positive gate voltage when the rest of the integrated circuit chip268is powered down. For example, the battery104may supply a small load of approximately one μA. Upon powerup of the integrated circuit chip268, the gate of the first FET274may then be controlled via a gate input transmitted by the rectifier control circuitry136or another processor144(e.g., CPU). Charge rails404used for the high side rectifier FETs (e.g., switches230,232) may also be used to drive the first FET274when system power is up. In another example, the first FET274is turned on at startup via a bootstrapping scheme as illustrated inFIG.4B, which represents a portion of the rectifier circuit200. For example, a diode408and a third capacitor412may be coupled to the drain conductor276leading to the first FET274and to the gate driver266. This diode-capacitor subcircuit generates a bootstrap voltage and transmits a bootstrap voltage signal to the gate driver266. The gate driver266then transmits a gate input to the first FET274based on the boot strap voltage that operates until the rectifier circuit200is up and running. The first FET274may be configured to operate in depletion mode FET, (wherein the FET is normally closed (ON) allowing current to pass, but is triggered to open (OFF) to impede current. In some embodiments, first FET274may be configured to operate in enhancement mode, wherein the transistor is normally open (OFF), but is triggered to close (ON). The ability of the First FET274to buck voltage without causing intermittent shutdown of the charging scheme allows the user device100to converse back and forth with the wireless charger108(e.g., via ASK/FSK) without interruption. This constant communication allows the user device100to quickly convey to the wireless charger108if the power coming from the wireless charger108is at risk or causing an over voltage event (e.g., the first FET274can communicate during an over voltage condition). For example, the user device100may send a request (e.g., a modulated wireless signal, such as a signal generated by the coil208) to the wireless charger108that the wireless charger modify/reduce the power that it is transmitting. The rectifier circuit200may operate under a tightly-coupled wireless power transfer scheme (e.g., having a receiving coil208matched to a specific/similar transmitting coil), but may also be able to operate under loosely-coupled arrangements (e.g., where the receiver coil208is matches with a typically larger transmitting coil). Transistor switching, such as the switching on and off of the first FET274can lead to noise/EMI that can be disruptive to communication with the wireless charger108. Noise can be controlled by adjusting the ratio of capacitors (e.g., 10-20 nano-farads to 700 nano-farads). Problems with noise may also be mitigated by switching at a high-enough frequency that is out of band for communication between the user device100and the wireless charger108. Noise may also be mitigated through modulating the control frequency or PWM frequency via dithering. The rectifier circuit200may be designed to work with any chipset, and may be used in a user device100that uses multiple coils208, or a device that uses multiband charging schemes (e.g., a single coil with tuning for frequency). For example, the rectifier circuit200may utilize multiple first FETs274that can receive different wireless power input from multiple coils208, or a tunable coil208. The rectifier circuit200may include two or more coils208, with multiple first FETs274and/or sets or switch networks228that are matched to a specific coil208, or to a specific set of coils208. For example, the rectifier circuit200may include two or more coils208arranged in parallel or in series. Each coil208may have different operational characteristics where specific coils208are more suited for receiving power from specific wireless chargers108that transmit power with specific wireless power characteristics (e.g., frequencies). The rectifier circuit200may also have multiple sets (e.g., or a plurality) of switch networks228and/or first FETs274, each operating with a specific coil208or a specific set of coils to in performing the rectification based on the wireless power characteristic of the wireless power unit, such as carrier frequency. For example, the rectifier circuit200may include two coils208, a high frequency coil and a low frequency coil capable of receiving high frequency wireless power input signals (e.g., 205 kHz) and low frequency wireless input power input signals (e.g., 110 kHz), respectively. The rectifier circuit200may then include two first FETs274and/or two switch networks228that are designed to engage specifically the high frequency coil and the low frequency coil, creating two matched sets of coils208to FETs274/switch networks228. These matched sets of coils208and FETs274/switch networks228ensure efficient reception and rectification of the incoming wireless power input signal. It is to be understood that embodiments of the methods disclosed herein may include one or more of the steps described herein. Further, such steps may be carried out in any desired order and two or more of the steps may be carried out simultaneously with one another. Two or more of the steps disclosed herein may be combined in a single step, and in some embodiments, one or more of the steps may be carried out as two or more sub-steps. Further, other steps or sub-steps may be carried in addition to, or as substitutes to one or more of the steps disclosed herein. Although inventive concepts have been described with reference to the embodiments illustrated in the attached drawing figures, equivalents may be employed and substitutions made herein without departing from the scope of the claims. Components illustrated and described herein are merely examples of a system/device and components that may be used to implement embodiments of the inventive concepts and may be replaced with other devices and components without departing from the scope of the claims. Furthermore, any dimensions, degrees, and/or numerical ranges provided herein are to be understood as non-limiting examples unless otherwise specified in the claims. | 36,173 |
11862987 | DETAILED DESCRIPTION OF ILLUSTRATIVE CONFIGURATIONS Sample configurations will be described with respect toFIGS.1-15for use in charging electrically powered vehicles, although those skilled in the art will appreciate that the teachings provided herein may be used in other non-vehicular resonant magnetic induction wireless power transfer systems. Such configurations are intended to be within the scope of the present disclosure. The contactless replaceable (swappable) battery unit described herein employs magnetic inductive coupling to accomplish charging of, discharging from, and communication between system elements to allow for a contactless battery unit that is permanently sealed in a rugged, dust-proof and water-resistant container. Without physical contacts, the battery is inherently safe since voltage and current are not available to the touch. The lack of conductive material also means that contact wear is eliminated. The case of the contactless replaceable battery provides the standoff distance between wireless resonance couplers. The battery modules also have the benefit of inherent galvanic isolation due to the contactless nature of the system. While circuit breakers, interrupts, or fuses may be incorporated within the battery unit housing, the use of wireless power transfer prevents shorts and ground faults in handling even in a conductive atmosphere or in submerged fresh or seawater applications. The sealed aspect of the battery unit prevents water and dust infiltration allowing for battery use in wet, dusty or explosive atmosphere environments. The sealed aspect also allows the deployment of internal (to the case) intrusion detection systems, both physical and electronic. The intrusion detection can be used to detect improper attempts at battery changes or attacks on the electronics containing the usage and charging records in an attempt to increase the battery unit's value on the secondary life battery market. In the near term, large scale (multi-kilowatt hour (kWh)) vehicle and ground site deployments are foreseen for the sealed contactless battery unit and charging stations. However, as electronics continue to miniaturize, inclusion of sealed contactless battery units into most or all replaceable battery applications will become possible. FIG.1 FIG.1illustrates an example of a sealed, contactless battery unit101in a sample configuration. A rugged sealed case102protects the interior components of the battery unit101. The material of the sealed case102may be a non-conductive material (e.g., fiberglass, Kevlar® composite) or metal. If the case is metal, the areas covering the wireless power transmission (WPT) couplings103and105and a surrounding guard band104and106must be non-conductive. Note that inFIG.1, an additional two wireless power transmission couplers are not shown on other sides of the battery unit101. Dependent on the voltage, current, or power the battery unit101is intended to supply, the number of WPT couplings103can vary from 1-to-n*m, where n is the number of flat sides of the sealed case102and m is the number of coupler installations per flat side (based on the ratio of available flat side area to coupler area). The geometry of the battery unit101may be varied with each additional flat side allowing additional WPT coupler installations. The size the battery unit101also may be varied depending on use, thus also allowing additional coupler installations on the available area of each flat surface. The size of the magnetic inductive couplers and coupler surface area may also be varied to obtain the desired number of couplers per battery unit101. Each coupler includes one or more flat coil assemblies with associated circuitry (e.g., filter(s), rectifier, voltage converter, voltage regulator) protected under the non-conducting charging surface portion of the battery case. The coupler is bidirectional in that it may be alternately used for charging when recharging and discharging when supplying power. A holding element107is included on each lateral corner of the sealed case102of the battery unit101as shown inFIG.1. The holding element107serves to both assist replacement (insertion and removal) and to hold the battery unit101firmly to minimize lateral vibration while in use or during charging. Although shown in theFIG.1example as corner mounted slides to fit the socket receptacle provided slots, other powered or unpowered mechanical elements (e.g. slides, rails, rollers, linear ball and roller bearings (either recirculating and non-recirculating), rack-and-pinon, roller bearing plates, threaded and un-threaded rods) and placement on (or integrated into) the case frame are envisioned to provide easy battery unit replacement and to hold the battery unit101in a sufficiently vibration-damped grasp. A locking retention element108may be included on the posterior end(s) of the battery unit101. The locking retention element108secures the battery unit101in position for use and charging. The locking retention element108also serves as a deterrent to inadvertent or malicious battery unit101removal. Portrayed in this example as a modified lock rod assembly, other mechanical, magnetic hydraulic, electromagnetic, and electro-mechanical holding element enabled or actuated constructions are feasible to provide or enable the retention and locking functions. An environmental control element109is shown on a posterior end of the battery unit101. The environmental control element109provides a connectionless interface for internal cooling and/or heating elements of the battery unit101to external cooling and/or heating elements available when in use or charging. Note that additional thermally conductive surfaces can be emplaced anywhere on the case not occupied by another element (e.g., the charging surface of the WPT coupler). In this configuration, the magnetic loop antenna for transmission and reception of inductive duplex communications between the battery unit101and a charging or discharging cradle (not shown) share the non-conductive surface areas with the wireless power transmission (WPT) couplers103and105. Dedicated non-conductive surfaces may also be used if differing antenna placement is desired. FIG.2 FIG.2illustrates the internal functional subsystems of the sealed contactless battery unit201(which may include the battery unit101fromFIG.1) as well as a discharge station202. The battery unit201is inserted or otherwise held in place adjacent to the discharge station202. The gap205between battery unit coupler206and the discharge station coupler204may be regulated by the case thickness or the combined case thickness and discharge station covering. Additional air gap205between couplings204and206may be imposed using standoffs or the holding elements107of the battery unit201. The discharge station202connects with the battery unit201using magnetic resonant inductance. In addition to the magnetic discharging signal, an inductively coupled communications system signal also may be present. The electrical power connection212conveys the electricity generated by the discharge station coupling204and is conditioned by the power management system203. The discharge coupling204is comprised of one or more flat coil electromagnet(s) and associated circuitry (e.g., filter(s), rectifier, voltage converter-regulator). The duplex communications link interface214between the discharge station202and the power station (e.g., a vehicle, a charging cradle, a power storage depot, or a business or residential emplacement) conveys digital information both to and from the battery unit201via the inductive communications link215to the discharge station202. The environmental control connection213supplies the desired cooling or heating media to the discharge station202. Since the battery unit101is sealed, radiative surface areas211of the battery unit201may interface with the supplied heating or cooling via conduction or convective heat transfer. Internal to the battery unit201is an environmental control system210that serves to manage and distribute the internal coolant resources (e.g., air, liquid coolant, phase change material). The environmental control system210provides heating or cooling throughout the battery array209and onboard electronics207and208. The battery array209consists of distinct cells, each connecting to the power management system208and the battery management system207and the environmental control system210. The distinct cells may be chemical cells, capacitive cells (e.g., ultracapacitors), reversable fuel cells or a mixture thereof, creating a hybrid array. The battery unit communications controller216is a gateway router with firewall security, preventing access to the internal network of the battery unit201without the appropriate key provided by the discharge station's202communication controller217. The battery unit communications controller216also serves to conceal the internal configuration of the battery unit201from external probing. Externally available information (e.g., electronic serial number, state of charge, quality score, summarized or publicly available sections of the usage log information) would be retained locally to the battery unit communications controller216. The discharge station communications controller217is the bridge router between all external networks and the internal WPT enabled communications network. In one configuration, secure internet communications protocols (e.g., Transport Layer Security) are required for any external network connection. Within the internet virtual private networking ‘tunnel,’ additional authentication and access control using data encryption may be required to access both the discharge station202and the battery unit201. As illustrated inFIG.2, the power management system208contains a mechanically hardened hardware security module (HSM)218and secure memory for logging219. The secure, encrypted non-volatile memory219is used for logging of the secured permanent record of all sensors embedded in the battery unit201. These sensors include time, temperatures, voltages, currents, pressures, and accelerations. The power management system208also serves to limit access to the cryptographic key vault held by the HSM218. The power management system208may record all communication sessions, physical intrusions, and software access/attack attempts. The power management subsystem208includes a communications processor (not shown) that interfaces only to the internal, encrypted secure network of the battery unit201. All data transferred over the power control subsystem208communications link both internal to the battery unit201and to and from external sources through the battery unit communications controller216is screened by an internal (to the power management system208) firewall. Since the battery unit201is intended to be permanently sealed, maintenance on the internals of the battery unit201is intended to be difficult. Provision for manufacturer-level maintenance (for instance replacement of a malfunctioning battery cell in the battery array209) is made in that the replacement event will be logged. Logging of manufacturer-level maintenance of the contactless battery unit will be enabled by the use of cryptographic keys embedded in the key vault. Use of a key will assure that a trusted facility has performed the maintenance. Both symmetric keys and asymmetric (public key) storage may be held in the HSM218. The power management system208has a battery backup, sized to allow for recording of sensor data before shutdown in the cases of a catastrophic failure like an external software or physical attack or an internal system failure of the battery unit201. FIG.3 FIG.3illustrates a sample configuration of the contactless battery unit201in a charging cradle. One benefit of the replaceable sealed, contactless battery unit201is that it can be charged offsite or while out of the electric vehicle, depending on the use. The offsite location allows access to power and cooling that allows for optimal controllable charging conditions. The charging station301in this example includes a surrounding enclosure302that shields and decouples the charging points202from the weather. The charging station301is supplied with power connections212and environmental control (e.g., coolant) connections213for each of the charging points202. This example uses four charging points202that connect wirelessly to the battery unit201. Each of the charging points202is independently controllable to optimize the charging voltages. In the charging station configuration ofFIG.3, the external communications link interface214is only needed at one charging point202for conducting the magnetically coupled duplex communications215. Additional communications links may be provided for redundancy; otherwise, internal connectivity may be provided to control the various sections. Since the wired power connections212, wireless power connections(s)214and wireless communications link(s)215are bi-directional, a charging station301can be used operationally as the discharge station202shown inFIG.2. Since battery units201can be charged at any charging station, potentially owned by different parties, the cryptographic services provided by the battery unit's HSM218can be used for data confidentiality, communications integrity, payment non-repudiation, owner identification and charging station301and battery unit201authentication. The battery unit201may be charged while mounted in the vehicle or at another, off-vehicle site. In one configuration, the charger slowly charges using low voltages so as to lower the cooling and power demands. In the case of high-power, short duration charging, the charging station301, however comprised, can supply power and cooling. The power and cooling needs may be generated from the historical, lifetime charging history supplied over the inductive communications system to the charging station301. When removed from the vehicle and emplaced into the charging station301, full or partial submergence in cooling liquid may be used both to regulate the case temperature (and thus the internal battery temperature) but also may be used as an electrical connection to earth ground in architectures where an earth ground is required by the wireless power transfer system and where a section of the sealed battery case may act as a ground contact with the liquid. The permanently sealed case prevents dust and water incursion to meet (or in excess) of NEMA 6 or IP67 requirements. For non-vehicle primary use, the same charging scenarios (e.g., charging in situ, or removing for off-site charging) apply. FIG.4 FIG.4illustrates an exemplary horizontal stack of replaceable sealed, contactless battery units401in a sample configuration. The battery units402,403, and404are independently swappable and would commonly be deployed in an n+1 array to maintain power levels during replacement. On the other hand, there may be scenarios where all batteries get replaced while the unit is not functional. In the example ofFIG.4, the discharge station is integral to the bottom tray405which also serves to hold the battery units402,403, and404in place assuring alignment of the bottom coupling units (not shown). In a horizontal arrangement, the side-mounted couplings412(note: only one can be seen in theFIG.4viewpoint) may be active, distributing power so as to even the power load or capacity of each battery unit402,403, and404. In deployments with vibration or lateral loads (e.g., vehicle movements, earthquakes), the horizontal array401may be equipped with vertical supports406. These vertical supports406could also be used to support and stabilize additional rows of battery units401. Additional rows could interface with lower rows and supply (or be supplied) with power and communications via the aligned bottom to top coupling emplacements. The locking and retention components407hold each battery unit402,403, and404in place on the tray405. In the portrayed configuration inFIG.4, a common environmental control interface411supplies the battery units402,403, and404with the needed heating or cooling while a single communications interface410provides the connection for exterior communications. A single power connection409is used to supply or deliver power depending on the use case. Additional environmental, communication, and power interfaces are deployable as needed (e.g., for cooling, bandwidth, or load respectively). The common environmental exchange component408allows for independent connectivity to allow replacement of individual battery units402,403, and404. In some deployments, individual cooling or heating connections to the battery unit402,403, and404also may be used. FIG.5 FIG.5illustrates an exemplary vertical battery unit array501in a sample configuration. The vertical battery unit array501shown inFIG.5is an example of an interconnected, stacked cluster of independent replaceable sealed, contactless battery units502,503, and504. The battery unit array501rests on a bottom tray505which provides links to exterior connections for power513, communications515, and environmental control514. A mechanical support system511holds the battery units502,503, and504in place and in proper alignment while a mechanical retention and locking system512allows ease of replacement and provides additional mechanical support against movement. An environmental exchange system510interfaces with each of the battery units502,503, and504and allows individual replacement of each battery unit502,503, or504as well as an exterior environmental connection514. The wireless coupling assemblies (not shown) on the tops and bottoms of the lowest battery units503and504(internal to battery case) allow for communication and power transfer. The topmost battery unit502uses its bottom mounted wireless coupling assembly (not shown) for communication and power transfer while its upper wireless coupling assembly509is unused and unpowered in this example installation. The right side-mounted wireless coupling assemblies506,507, and508are available for interconnection to another vertical stack if desired as are the left side-mounted wireless coupling assemblies (not shown). All wireless coupling assemblies not interconnected will remain unpowered. FIG.6a FIG.6aillustrates a vehicle application of a cluster of independent replaceable sealed, contactless battery units in an electrically powered construction vehicle601. The construction vehicle601may be a chemical/electrical hybrid. As illustrated, a battery unit socket array602is installed on the vehicle (e.g., a dump truck)601allowing easy access for loading and unloading of battery units201. Eight individual sockets603are available for insertion of a battery unit in this illustrative example. One or more WPT coupling assemblies may be constructed on each flat side of the socket array602. In case of a mismatch in assemblies per side on the vehicle socket and the battery unit, only those couplings in geometrical alignment with other battery units or wireless transmission couplers on the vehicle601will be enabled for wireless power transfer. FIG.6b FIG.6billustrates a sample configuration of a construction vehicle, such as the exemplary dump truck601fromFIG.6a, refueling using contactless battery units in a sample configuration. As illustrated, the replacement battery unit604has one or more coupling assemblies605installed on the flat side(s) of the battery unit604for communication of power and data. Environmental interfaces606are installed at each end of the replacement battery unit604(those not occupied by a wireless coupling assembly). The battery unit socket array602allows easy access to the battery unit socket. In this example, the battery unit socket array602is equipped with a secondary access607. By inserting at608a replacement battery unit604, the previously installed, presumably depleted battery unit is pushed out of the battery socket(s) at609via the secondary access607. The environmental interface in this example relies on ambient air cooling or connections in the hatches of the battery unit socket array602. FIG.7 FIG.7illustrates a sample configuration of a contactless battery unit configured for handling.FIG.7illustrates the customization potential of the sealed contactless battery unit101. In this example, the battery unit101has been equipped with vias701and702in the body of the battery unit101that allow for carriage and installation by lightly modified, conventional handling equipment (e.g., a forklift). The parallel tubular construction through the battery unit's center of mass of the vias701and702allows for positioning for insertion into a socket without tipping or rolling. Once installed, the vias through the battery unit also may be reused, providing additional conduction cooling, augmenting other installed environmental control interfaces109. FIG.8 FIG.8graphically illustrates an example of a battery life versus use model in sample configurations. Illustrative examples of battery quality models are shown inFIG.8. The x-axis803depicts time while the y-axis801shows battery quality802as determined from correlation with a detailed, multi-variant model of battery quality. The simplified linear battery life models are shown to illustrate the variables in determining battery quality in a graphical form. A quality threshold811is drawn to show the value for which a replaceable sealed battery unit of a particular design becomes valueless. Other thresholds can exist, for instance, where the battery quality becomes unfit for a vehicle-based application. All illustrative examples depict linear relationships over time; however, more accurate models can include differing linear segments (i.e., changes in slope) over time to better match the impact to capacity variance over time. The simplest case of estimating battery quality is shown for the charged, stored battery unit. Here the temperature of the storage facility is the main determinant of quality with a cooler facility yielding a higher quality estimate804than that of a battery unit stored at a higher temperature quality estimate805. For simplified models for a normal operating profile (regular, periodic charging without fast charging (overvoltage) or deep discharge), the estimate806shows a higher quality due to discharge cycle from 80% state of charge to 20% state of charge while the estimate807shows the relative impact of a discharge cycle from 90% to 10% state of charge. A catastrophic event's effect on a quality model810is shown. With this model, a linear decrease in battery quality over time until an event (e.g., internal short circuit, internal open circuit, internal coolant depressurization, high acceleration (impact)) damages the battery unit, leading to an immediate drop in quality. Quality models showing the effects of fast charging and/or deep depletion are shown by models808and809. The battery unit yielding the model808is periodically driven into deep (e.g., <2% current state of charge capacity) and then is charged overnight. The battery unit generating the model809is periodically driven into deep (e.g., <2% current state of charge capacity) and then is charged using a fast charger. The relative quality levels show the impact of both the deep depletion and the fast charging effects on the battery array. Battery Thermal Management The battery unit101supports an internal thermal management system coupled to the sealed exterior case102. The sealed exterior case102may then be in contact with the elements of the vehicle601or charging station301that supply cooling or heating without penetration of the sealed battery case102. The battery unit101also may have an internal electrical heating system for pre-heating the internal battery array. Sensors and History The sealed permanent nature of the battery unit101allows for deployment of permanent internal sensors for voltage, current, temperature and kinetic accelerometer(s) that may be used to generate a historical profile of battery use. Information on temperature, voltage levels, current levels, and 3-axis acceleration(s) to the individual cell level can be generated and retained. This historical profile allows predictions to be made regarding the future capabilities of the battery unit101. These predictions allow for formulation of a valuation on the secondary market for batteries similar to the mileage (odometer reading) of an automobile for used cars. The permanently sealed contactless battery unit101with wireless connections has a lifetime history of storage, charging and discharging events by having instrumentation (voltage, current, internal and exterior temperature(s), acceleration) built permanently into the battery array and the sealed compartment. A historical usage profile (charging, discharging, voltages, temperatures, storage, accelerations) may be made for each battery unit101. Acceleration loads that detect rough handling are also considered. This lifetime profile allows a battery unit quality measurement to be formulated. The full history also would be available, including the creation of an “at-a-glance” single numerical figure for quality (similar to the odometer on a used car). The chronicled information acquired by the battery unit's sensors and stored by the battery back controller can be used to produce a correlation to a charged-once, unused, un-stored, undischarged battery model. A battery with a perfect charging history (e.g., freshly produced, ready for first use) would have a correlation of 1 Daga (note: a new unit of measurement). As the battery unit is cycled over time, the value decreases giving the user/owner an estimate of the battery life and the value to the 2nd and 3rd life markets. For an example, a battery with, for example, a rating of 600 millidagas (md) would be moved from the fleet usage pool to a 2nd life application (such as grid augmentation). The 600 md (or 0.600 D) threshold for vehicular use is an example and could vary with market desire, owner preference, and regulatory requirements. Obviously, overcharging, overheating, and fast discharging that damage a battery would be accounted for in a lower Daga score as a deviation from the model. Accelerometers measuring shock would also contribute to the Daga score. Casement intrusion detection would also contribute to the Daga score computation as would detection of cyber-attacks versus the battery unit controller. As an item of value, the Daga score would be kept in secure storage in the battery unit101and could be uploaded to a network (e.g., internet attached server based) storage when charging in a charging cradle. Since the battery unit sensor data can be uploaded, it is possible that the usage profile or updates to the usage profile may be generated by aggregating data from a population of deployed battery units rather than by estimation or lab testing. It is noted that different quality models versus usage can exist for each specific rechargeable battery chemistry (e.g. Lead-acid, Nickle-Cadmium (NiCd or Ni-Cad), Nickel-metal hydride (NiMH), Alkaline (predominately Zinc (Zn) and Manganese dioxide (MnO2) based) and the Lithium Ion, Lithium-Sulfur, and Lithium-Polymers (e.g. Li-nickel manganese cobalt oxide (NMC), Li-nickel cobalt aluminum (NCA), Li-iron phosphate (LFP) and Li-titanate (LTO))), solid-state battery, and battery analog (ultracapacitor, reversable fuel cell) and for each hybrid energy storage system where two or more technologies or chemistries are used. Use of the Daga quality metric could also be used in the place of load testing of a battery unit to generate a snapshot of the battery unit's state of health. Communications and Control Magnetic inductive communications (as detailed, for example, in U.S. Pat. No. 10,135,496, entitled “Near field, full duplex data link for use in static and dynamic resonant induction wireless charging” and in U.S. patent application Ser. No. 16/570,801, filed Sep. 13, 2019, also entitled “Near field, full duplex data link for use in static and dynamic resonant induction wireless charging”) allow secure and sophisticated communications enabling battery status, state of charge, and historical charging, discharging data to be exchanged as well as closed loop control of the charging signal. The descriptions of these patent documents are hereby incorporated by reference. Use of alternate or supplemental communications means by the addition to the battery unit of a short-range transceiver (e.g., RFID, Bluetooth, Wi-Fi, or Zigbee) also may be useful in certain deployment configurations or to meet customer or regulatory requirements. Use of longer-range communications means such as cellular radio could also be used if added to the battery unit101or discharge cradle202for those same reasons. Bi-Directional Use The battery's wireless charging unit may be capable of bi-directional use, supporting both charging and discharging of the battery. The wireless charging system may consist of one of more wireless couplers and be reused for discharge. Optionally, separate wireless inductive couplings may be used for charging and discharging with each sized for the expected power transfer rate. FIG.9 FIG.9shows an exemplary high-level functional diagram for power flow through and conversion by a bidirectional wireless power transfer system in a sample configuration. While certain components are by nature bi-directional and symmetric in operation (e.g., the resonant induction circuit also known as an the open core transformer) and can be shared, the forward (charging) and reverse (discharging) power transmission paths will depend on divergent simplex architectures, requiring switches909, control logic (not shown), and communications link (also not shown) to activate and complete the power transmission paths for each of the forward (charging) and reverse (discharging) use scenarios. In the forward direction, power is nominally delivered from the utility grid901. Dependent on the grid connection, the power may be single phase alternating current (AC), direct current (DC), or multi-phase alternating current. The utility grid901includes any transformers needed to step down voltages from high voltage transmission lines. In this example, single phase AC is delivered by the utility grid901, where a sufficient capacitance exists so that the power factor is adjusted to approximately 1 (unity). The AC power may be converted to DC by the AC/DC902converter. This function can be achieved by an active (switch-based) or passive (diode-based) rectifier. The DC/AC converter903takes the input DC power and converts it to a high frequency AC (nominally 85 kHz in this configuration) sinusoidal signal. The DC/AC conversion operation by the DC/AC converter903can be accomplished using an inverter. The AC power signal may be passed to the coupling, a resonant air core transformer904, with its primary and secondary coils. The AC power is converted to magnetic flux in the primary which is inductively coupled with the secondary. The secondary coil converts the received magnetic flux into an AC power signal. The AC power signal is passed to an AC/DC converter905. The AC/DC conversion function can be achieved by an active (switch-based) or passive (diode-based) rectifier. The resultant DC signal is used to charge the energy storage device906, nominally a rechargeable chemical battery, but also could be a one or more of a capacitor bank, reversable fuel cell, solid state battery or a hybrid combination of the aforementioned. The DC signal can also be used to power an electrical device directly. Being bidirectional, the energy storage device906can output stored power as direct current to the reverse transmission path. The DC power is converted by the DC/AC inverter907to the necessary AC power signal. This AC power signal is input into the resonant induction circuit904. In this reverse path scenario, the coils are reversed in operation from the forward path. The AC power is converted to magnetic flux in the primary coil of the open core transformer904which is inductively coupled with the secondary coil. The secondary coil converts the received magnetic flux into an AC power signal. The resultant AC power is adjusted in frequency by the AC/AC converter908. In one configuration, an AC/DC/AC converter is used as the AC/AC converter908, where the AC/AC frequency adjustment operation is accomplished using an AC/DC rectifier and then converted from DC to AC at the required frequency by an inverter circuit. The utility grid901in this example includes the necessary transformers to translate the AC power to the desired voltage and AC/DC conversion, if necessary, for interfacing with utility supplied power. FIG.10 FIG.10is a block diagram illustrating circuitry for performing methods and implementing processing features according to example configurations. For example, the processing circuitry ofFIG.10may be used to implement the cryptographic processing functions of the communications controller, the thermal and power management functions, the intrusion detection functions, and the management of the historical usage profiles and quality models. All components need not be used in various configurations. FIG.10illustrates one example of a computing device in the form of a computer1000that may include a processing unit1002, memory1004, removable storage1006, and non-removable storage1008. Although the example computing device is illustrated and described as computer1000, the computing device may be in different forms in different configurations. For example, the computing device may instead be a smartphone, a tablet, smartwatch, or other computing device including the same or similar elements as illustrated and described with regard toFIG.10. Devices, such as smartphones, tablets, and smartwatches, are generally collectively referred to as mobile devices or user equipment. Further, although the various data storage elements are illustrated as part of the computer1000, the storage may also or alternatively include cloud-based storage accessible via a network, such as the Internet or server-based storage. Memory1004may include volatile memory1010and non-volatile memory1012. Computer1000also may include, or have access to a computing environment that includes, a variety of computer-readable media, such as volatile memory1010and non-volatile memory1012, removable storage1006and non-removable storage1008. Computer storage includes random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM) or electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD ROM), Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium capable of storing computer-readable instructions. Computer1000may further include or have access to a computing environment that includes input interface1014, output interface1016, and a communication interface1018. Output interface1016may include a display device, such as a touchscreen, that also may serve as an input device. The input interface1014may include one or more of a touchscreen, touchpad, mouse, keyboard, camera, one or more device-specific buttons, one or more sensors integrated within or coupled via wired or wireless data connections to the computer1000, and other input devices. The computer1000may operate in a networked environment using communication interface1018to connect to one or more remote computers. The remote computer may include a personal computer (PC), server, router, network PC, a peer device or other common network switch, or the like. The communication connection accessed via communication interface1018may include a Local Area Network (LAN), a Wide Area Network (WAN), cellular, Wi-Fi, Bluetooth, Zigbee, or other networks. According to one configuration, the various components of computer1000are connected with a system bus1020. Computer-readable instructions stored on a computer-readable medium are executable by the processing unit1002of the computer1000, such as a program1022. The program1022in some configurations comprises software that, when executed by the processing unit1002, performs operations according to any of the configurations included herein. A hard drive, CD-ROM, and RAM are some examples of articles including a non-transitory computer-readable medium, such as a storage device. The terms computer-readable medium and storage device do not include carrier waves to the extent carrier waves are deemed too transitory. Storage can also include networked storage, such as a storage area network (SAN). Computer program1022may be used to cause processing unit1002to perform one or more methods or functions described herein. It should be further understood that software including one or more computer-executable instructions that facilitate processing and operations as described above with reference to any one or all of steps of the disclosure may be installed in and sold with one or more of the battery units or discharge units described herein. Alternatively, the software may be obtained and loaded into one or more battery units or discharge units in a manner consistent with the disclosure, including obtaining the software through physical medium or distribution system, including, for example, from a server owned by the software creator or from a server not owned but used by the software creator. The software may be stored on a server for distribution over the Internet, for example. Also, it will be understood by one skilled in the art that this disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the above description or illustrated in the drawings. The configurations herein are capable of other configurations, and capable of being practiced or carried out in various ways. Also, it will be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The components of the illustrative devices, systems and methods employed in accordance with the illustrated configurations may be implemented, at least in part, in digital electronic circuitry, analog electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. These components also may be implemented, for example, as a computer program product such as a computer program, program code or computer instructions tangibly embodied in an information carrier, or in a machine-readable storage device, for execution by, or to control the operation of, data processing apparatus such as a programmable processor, a computer, or multiple computers. A computer program may be written in any form of programming language, including compiled or interpreted languages, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. Also, functional programs, codes, and code segments for accomplishing the systems and methods described herein may be easily construed as within the scope of the disclosure by programmers skilled in the art to which the present disclosure pertains. Method steps associated with the illustrative configurations may be performed by one or more programmable processors executing a computer program, code or instructions to perform functions (e.g., by operating on input data and generating an output). Method steps may also be performed by, and apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC, for example. The various illustrative logical blocks, modules, and circuits described in connection with the configurations disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an ASIC, a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random-access memory or both. The elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example, semiconductor memory devices, e.g., electrically programmable read-only memory or ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory devices, and data storage disks (e.g., magnetic disks, internal hard disks, or removable disks, magneto-optical disks, compact disc ROM (CD-ROM), or digital versatile disc ROM (DVD-ROM). The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry. Those of skill in the art understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. Those skilled in the art may further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the configurations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. A software module may reside in random access memory (RAM), flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A sample storage medium is coupled to the processor such the processor may read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. In other words, the processor and the storage medium may reside in an integrated circuit or be implemented as discrete components. As used herein, “machine-readable medium” means a device able to store instructions and data temporarily or permanently and may include, but is not limited to, random-access memory (RAM), read-only memory (ROM), buffer memory, flash memory, optical media, magnetic media, cache memory, other types of storage (e.g., EEPROM), and any suitable combination thereof. The term “machine-readable medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, or associated caches and servers) able to store processor instructions. The term “machine-readable medium” shall also be taken to include any medium, or combination of multiple media, which is capable of storing instructions for execution by one or more processors, such that the instructions, when executed by one or more processors cause the one or more processors to perform any one or more of the methodologies described herein. Accordingly, a “machine-readable medium” refers to a single storage apparatus or device, as well as “cloud-based” storage systems or storage networks that include multiple storage apparatus or devices. The term “machine-readable medium” as used herein excludes signals per se. Alternative Configurations External Cooling/Heating Supply Depending on the power load, charging load, external ambient temperature and/or battery chemistry, environmental couplers may need to be added to the contactless battery unit for the use of forced air or liquid coolants from an external supply. While the sealed case provides contact surfaces for cooling by conduction and convective means, connection ports allowing limited access to the battery pack may be needed. While this installation type complicates the replacement of a battery unit, the segregation of the battery unit's internal cooling system would limit access to the rest of the sealed battery unit. The environmental control electronics with its temperature sensor network would be supplemented with the addition of pressure sensors in those contactless battery units designed to allow the ingress and egress of coolants via air or liquid valved connection ports. In some deployments, external heating of contactless battery units via use of heated forced air or liquid coolants would be similarly equipped and monitored. Fuel Cell Use The contactless replaceable battery unit101described herein could be used with fuel cells in place of chemical batteries. Offboard fueling would provide the same warehousing and safe charging of potentially hazardous fuels and oxidizers. The contactless design would provide the same lack of electrical contacts. The fuel and oxidizer inputs would by necessity compromise the sealed case but would be opened for replenishment. The replenishment facility could be sited away from the use site, granting more protection to the driver and passengers when used in a vehicle or for those nearby in non-vehicle use. Supplied Voltage FIG.11 FIGS.11A,11B,11C, and11Dall show the high-level construction of a contactless battery pack with differing options. FIG.11Aillustrates the simplest design with the contactless battery case1101, the battery payload1102, the WPT inductive coil assembly1103, the battery pack controller1104, the inductive receiver antenna1105and the inductive transmission antenna1106. The contactless battery case1101serves to galvanically isolate and protect the electronics and batteries within. The battery payload1102, in this example, is an arrangement of serial cells in a fixed number of parallel banks to deliver a set voltage and current capacity. FIG.11Billustrates an example of a contactless swappable battery capable of sharing current capacity through a second WPT inductive power transfer coil1108. A second transmission antenna1107and a second receiver antenna1109are also included in this design. FIG.11Cillustrates an example of a contactless battery pack with two coil assemblies1103and1108each with transmission antenna1106and1107and reception antenna1105and1109. In this example, battery cells are wired serially to produce banks1110,1111,1112, and1113which then can be joined in serial or parallel fashion using the switching matrix circuitry1114. FIG.11Dillustrates an example of a contactless battery pack with a single inductive coil assembly1103that is used for power transfer with a single set of inductive receiver antenna1105and transmitter antenna1106. The battery cells are connected serially in banks1110,1111,1112, and1113which can be combined using the switch matrix1114. A DC/DC converter1115allows output voltage level adjustment from the switched battery banks. Battery Pack Management System (BPMS) FIG.12 FIG.12illustrates a high-level view of an installation1201of contactless swappable battery packs under control of the Battery Pack Management System (BPMS)1202which communicates with the Battery Management System1203of the served vehicle, building, or other electrically powered equipment. In theFIG.12example, the installation1201comprises a battery pack rack that holds slots (discharge cradles) for 5 contactless swappable battery packs1204,1205,1206, and1208. Each slot has electrical bus and cooling connections which are not shown for the purposes of clarity. Each slot is equipped with an inductive communications transmit and receive antenna that communicates with corresponding antenna of the contactless swappable battery pack. Using the inductive communications interface1209, the BPMS1202can communicate bidirectionally with each (if present) contactless swappable battery pack1204,1205,1206,1207, and1208. In this example, an inactive communications interface1210is present due to the empty battery pack slot1207. In this example configuration, the BPMS1202communicates bidirectionally with the battery management system1203over a wired link to control the charging operation, although a wireless link also could be used. Configuration Information Flow FIG.13 FIG.13illustrates the information flows between the major subsystems of a contactless swappable power system. In some configurations, these information flows may be adapted from, or extensions to, existing standardized messaging for corded or wireless charger systems (e.g., ISO 15118, SAE J2847). The control and coordination of multiple contactless swappable battery packs requires extensive additions in function to a conventional battery management system (BMS)1301. In theFIG.13configuration, these additional functions and capabilities are shown concentrated in the Battery Pack Management System (BPMS)1302which bridges the information flow between the vehicle's BMS1301and the Contactless Swappable Battery (CSB) pack array1303. In theFIG.13configuration, the CSB array1303contains a first CSB1304and a second CSB1305. The CSB array1303may include battery packs sufficient for delivery of the intended power and duration and may also include additional standby CSBs for handling of unexpected power needs, to maintain power levels during swapping (hot swapping), or as a backup. Some CSB array1303slots may on occasion be left empty. As a periodic background task1306, when a CSB is added to the array1303, or as commanded, the BPMS1302will initiate and exchange interrogation messaging1306. During interrogation1306, the BPMS1302will initiate a query1307to the second CSB1305and second query1308to the first CSB1304. The first query1307may include an identity request, an authentication challenge, and a health, status, and capabilities request as may the second query1308. These query requests can occur in any order and at any time. Alarming (where the CSB1304and1305or the CSB array1303updates its status without a BPMS1302request), heartbeat, and time synchronization messages are not shown. A queried CSB1304or1305may respond at1312with stored values, calculated values (e.g., a cryptographic challenge response), or initiate a built-in test to determine the health of the battery cells and the performance capabilities of the first CSB1304and second CSB1305in the CSB array1303. The responses1310and1311may occur in any order. When the BMS1301requests at1313that a power (i.e., voltage and current) level be delivered, that information is passed to the BPMS1302which then commands at1314and1315the individual CSBs1304and1305present in the CSB array1303to configure (or reconfigure) to deliver their portion of the commanded power level. Each CSB1304and1305will respond at1316and1317when power levels are set. The BPMS1302will collect all responses1316and1317and will signal the BMS1301when power is available using a response1318to the original power request1313. The response1318may also include a state-of-charge (SoC), run-time estimate, or power capacity (e.g., kilowatts per hour) estimates. Supported Illustrative Scenarios SCENARIO 1: Initialization, capacity, use, and drain compensation In an exemplary scenario, a single CSB contains 100 lithium-ion cells at 2000 milliamp-hours per cell. The lithium-ion battery can range from 4.2 volts per cell to 3.0 volts at cutoff. 10 CSBs are equipped in this example. The Battery Pack Management Controller (BPMC) receives a request for 100 volts at 10 amps. Under control of the BPMS, the individual CSB switch matrix (e.g., switch matrix1114inFIGS.11C and11D) may reconfigure the series/parallel relationships of series and parallel banks of cells within the CSB. In this example, the BPMS polls the individual CSBs to find the state of charge (SoC) in the configuration. Battery cell age and temperature also are also considered. Using an SoC of 3.5 volts per cell, the CSBs are arranged in banks of 3 with 33 parallel banks for an output voltage of 10.5 volts. Each parallel bank of cells can supply 6 Amp-Hours. At 10 Amps, each bank must supply 303 milliamps. The DC/DC converter of each CSB may be used to level the output voltage to 10 volts. Efficiency of the DC/DC converter is assumed to be 80%, so the expected current draw is factored to expect 12A, or 363 milliamps per bank. The efficiency of the 1:1 open core transformer at resonance is assumed to be 95%, raising the current needed to 12.6 Amps. This efficiency includes the inverter and rectification stages. Since 10 independent CSBs supply the current, 1.26 A will need to be supplied by each CSB. With each CSB having 33 banks of 3 cells each, 382 milliamps will be required per bank. Using this calculation, the BPMC can report 5 hours of power available. As operation continues, the voltage supplied by each cell will decrease. The DC/DC conversion will be adjusted to return the CSB output to 10 volts. Alternately, as described in the commonly owned U.S. Pat. No. 9,754,717, issued Sep. 5, 2017, the WPT system can supply the needed voltage adjustment using a reactance generator to adjust the amplitude of the generated magnetic wave and thus the output power. SCENARIO 2: Battery Pack Failure. Battery Pack failure calls for immediate replacement. In a multi-pack environment, the additional remaining packs may optionally provide uniform voltage (Vout) albeit at a lower current. For example, it is assumed that a 3-pack system has a catastrophic failure of one pack. In one option, the remaining two packs will continue to supply Vout giving the load 2/3 the total current via their own inductive links. The failed battery pack is galvanically isolated by the disabled inductive power link. Alternately, if both current and voltage levels need to be maintained, the remaining battery packs can boost output using the inter-battery pack communications to coordinate outputs to maintain total output power. Here, additional limitations may exist to prevent side-effects, such as thermal damage or battery-lifespan depletion (for instance through excessive current draw and thermal effects). Thresholds and rules for abiding these limitations are kept by the Battery Pack Management Controller (BPMC)1302. SCENARIO 3: Battery Cell Failure in One Battery Pack This scenario assumes successful isolation of the failed battery cell within the battery pack, otherwise scenario 2 applies. In this case, the battery pack DC/DC converter is reconfigured to continue to send the same voltage to the inductive coil allowing the battery pack to continue to supply power to match its peer packs (in a multipack system) or required power load. The battery pack can then be exchanged at a depot. It may be repaired or decommissioned. Alternately, the battery pack can be derated, recharged and offered for lower capacity or lower voltage uses. The derating may include a slower recharge rate with limits on charging voltage, charging current, or both. SCENARIO 4: Mid-Life Capacity Drop As battery packs age, the capacity decreases and can be measured by the discharge voltage drop from fully charged to threshold (both the fully charged and threshold levels vary by battery chemistry) at operating temperature. The battery pack charge and discharge history (which includes all past charging and discharging events with parameters such as battery cell temperature, charge voltage, discharge current and age since construction for the battery pack and each cell) is known and stored in each battery pack's persistent memory as information aggregated from prior uploads received during charging sessions at the administration center. The aging battery pack Daga score is compared to a threshold each charging session. If the Daga score falls below a first threshold value, the battery pack may be derated and offered for lower capacity or lower voltage uses. The derating may include a recharge rate ceiling. If the Daga score falls below a second threshold, the battery pack is decommissioned for safety purposes. Until a derating threshold is reached, the battery pack will compensate for cell voltage declines using the internal mechanisms which include, battery cell reconfiguration, DC/DC conversion, and/or adjustable reactance. SCENARIO 5: Battery Charge Depletion In normal use, a battery cell output voltage will decrease as the cell's electron reserve is depleted. For instance, an example Lithium battery cell's output voltage fades from a maximum, fully charged, voltage of 4.2 volts to a floor of 3.0 volts before being taken offline by the Battery Pack Management Controller (BPMC)1302. Using the contactless swappable battery pack, the output voltage may be controlled at a steady 3.5 volts throughout the period of use or before the 3.0 volt-per-cell voltage safety floor is reached. Logistics Chain for Fulfillment FIG.14 FIG.14illustrates an exemplary distribution network for the transport, production, warehousing, pre-positioning, storage, charging, exchange, and replenishing of a delivery system for contactless swappable battery units. Production1401allows new contactless swappable battery packs to enter the market. Production1401also may include the refurbishment and repair of existing contactless swappable battery packs to bring them back to the marketplace. Uncharged battery packs may be shipped to a charging facility1402, where they are stored in a warehouse1403charged or uncharged, or moved uncharged to a warehouse with charging capability1404to prepare the battery pack for use. Production1401may be a single facility or multiple facilities. Charging facilities1402allow the charging of a contactless swappable battery packs. Charging facilities1402may be located at the production sites, within warehouses, within transport depots, or at sites where electrical power is cheap and/or plentiful. Alternately, charging facilities1402may be located where adequate power is available and the combination of electricity costs and transport costs are low. Charging facilities1402associated with particular power generation (e.g., windfarms, hydro-electric power) may allow for battery packs to be labeled with electrical load origin. Warehousing1403can be used to store charged, uncharged or partially charged battery packs. Power Warehouses with charging facilities1404can be used to keep battery packs ready for deployment via charge level monitoring and topping off either periodically or immediately prior to release. Transport of new and refurbished battery packs between non geographically co-located sites in the distribution network1405is accomplished via a shipping network1406. The distribution network1405and shipping network1406coexist with and supply the in-use segment1407of the servicing network1408. The servicing network1408contains the depots for charging, storage, testing and loading capabilities. The in-use segment1407contains the battery packs currently installed in vehicles, factories, hospitals, off-grid installations, and other battery powered equipment. A full depot1409can store battery packs, charge them, and exchange deplete packs for fresh packs using handling equipment. In some cases, the full depot may be fully automated with robotic handling equipment. A management unit (MU) with wired/wireless network interconnection is expected for each full depot1409. The full depot1409can be sited anywhere, but preferentially near transport nexus where plentiful power is available. An exchange depot1405acts as an exchange point for depleted battery packs. Warehousing and loading and unloading equipment is available at an exchange depot1405. The exchange depot1405relies on transport of charged battery packs (for instance via barge, rail, or roadway) and backhauling of depleted battery packs for replenishment of the local warehouse. A charging station1407allows in-situ recharging of battery packs without the dismounting and replacement of the depleted battery packs. Charging stations may be co-located with full depots1409. Specialized mobile or portable charging cradles allow for contactless charging. System for Distribution, Planning, and Recharging The Management Unit (MU) is a specialized Assets Management System (ASM), for instance one based on the IBM Maximo Enterprise Management System customized for the multi-dimensional aspects of the Contactless Swappable Battery (CSB) system (which include not only serial number asset tracking, but also the current location and use of the CSB, but also the state of charge and battery pack health) with added security, multi-party access control, redundant databases and Geographical Information Systems (GIS). The MU may be offered as a hosted (cloud-based) system or as an on-premise hardware and software system, based on generic high-availability computing platforms sized to fit processing and storage needs. The MU may be used to provide logistic management and control functions for the warehousing, transportation management, and shipping to the past, current, and planned locations for individual (or groupings) of contactless swappable battery packs. The MU provides a platform for storage and analysis of battery pack information such as battery pack model and serial numbers, current charge state, power storage and delivery capability rating, cooling setup available, voltage and current capability, age, and estimated service lifespan. The MU also contains charger information including wait times, usage rate, in-use indicator, charging power level, physical sizes, and cooling arrangement. The MU may also contain the source of electrical power for each charger, for instance the customer may desire all power from renewable or ‘carbon-neutral’ sources so battery packs may be so charged and labeled both in the MU and in internal memory. The MU may be located at the warehouse or depot level, or deployed to serve a regional, national, or continental area in an administration center. MUs can be configured in distributed clusters or in hierarchal fashion to cover broadening geographic service area or high-use service areas. The MU, or an MU cluster, may further contain a programmable expert system that uses machine learning techniques. The expert system may be used for pre-positioning, optimization of battery pack distribution, daily, monthly, seasonal or annual trending, out-of-stock predictions, out-of-stock warnings, out-of-stock redirection corrections, price of electricity and transport arbitrage, contracted delivery levels, partial charge evaluation versus charging time based on available charging resources (e.g., number of charging cradles at a depot or in a geographic area, availability of warehoused partially charged units, units available for shipment with time-of-arrival forecasting). Customers of the battery service may connect to the MU to see inventory and place reservations for battery packs along intended routes. Fully automated vehicles can also make use of this service offered by the MU. Designated Management Unit(s) provide the source and change control for encryption, authentication, and access controls via the data network. The designated MU collects telemetry and alarm data from battery packs under its oversight from communications equipped charging cradles, discharging cradles, recharging stations, or from the battery pack itself if equipped with long-range communications (e.g., via a commercial cellular wireless network). The MU is also the control access point for battery pack diagnostics and performs the collection, display and storage of battery pack or charging cradle alarming. The MU may be used for controlling power distribution with the addition of accounting logic, transport costs, and pricing costs. Using electrical prices, transportation costs, inventory of battery packs and trend data (including contracted service levels and reservations), the MU allows for control and analysis of the operations for charging, transport and re-positioning of battery inventory to take advantage of local or regional electricity costs. FIG.15 FIG.15illustrates an exemplary network for the monitoring and control of physical and informational assets in a battery exchange network. In particular,FIG.15illustrates a charging and exchange network using a hierarchal architecture for the command and control of contactless swappable battery related (e.g., battery units, chargers) physical assets and battery related data and battery generated telemetry data. As illustrated inFIG.15, the administration center1501contains the MU software implemented on distinct hardware platforms for the purposes of illustration. Actual MU data storage and software could be run on distributed cloud networks or redundant computing hardware systems. The administration center1501can be implemented by each owner, or by each production center and may be implemented as a single site operation or distributed among multiple redundant sites. In the administration center1501, staff1502manage the flow of information via consoles1503. In this configuration, all information storage is accomplished by a database1504. This contactless swappable battery packs database1504contains partitioned information on the users, owners, current or last-known geographic location, current or last-known state-of-charge, battery pack health, and encryption keys. Billing may be done by the administration center1501or locally with prompt reporting to the administration center1501to manage inventories. The database1504also contains the geographic locations of every charger, power generation facilities, and warehouse depots as well as generic geographic mapping information and transport network information. In this configuration, the administration center1501uses a secure internal local area data network1505to protect user, battery pack, and owner information. The telemetry server1506processes information about the use and health of the battery pack stored in the database1504. Use and health information is developed by the sensors on and within the battery pack and reported as telemetry nominally when the battery pack is charging, and data connectivity is performed through the battery pack charger/charging cradle. The location, condition, usage, and cryptographic identity for each charger is also uploaded to the database1504via the telemetry server1506. The security server1507generates and maintains the encryption keys necessary to secure and authenticate each battery pack and battery charger under control of the administration center1501. The inventory server1508not only keeps track of all battery packs under management of the administration center1501, both in use and warehoused, but also enables user reservation and forecasting of need. This forecast can be used to pre-position battery units for individual users, but also determine trends based on seasonal, calendar, or time-of-day battery unit exchanges and use from both the battery pack perspective as well as the user's or user's groups perspectives. The inventory server1508contains a Geographic Information Server (GIS) used to store, visualize, analyze, and interpret geographic data related to inventory as stored as geospatial data in the database1504. In this example, a wired datalink1509provides data interconnection via encrypted virtual private networking (VPN) between the administration center1501and all other sites using a packet data network1510(e.g., the internet). Connected sites1514may include a local secure LAN1515. Connected sites1514will nominally house a local inventory server1516and may include an operator terminal1517for local queries and data entry and a local (store and forward) telemetry server1518. From the packet data network1510(and using VPN tunneling for security) a wired datalink1511may be used to access wide-area wireless terrestrial communication networks1512(e.g., a cellular network). Also using a data interconnection1513to the public or private data switching network (e.g., the internet)1510, the connected MU site1514may reside at a depot, warehouse, repair facility, or exchange site. At these connected MU sites1514, both the local inventory server1516and local telemetry server1518may exchange information with the administration center1501via the secure (VPN) data channel over the local wired connection1513. Workers at operator terminal1517using the secure local network1515may communicate with both the internal resources and external administration center1501. The secure local area network1515also may be used to provide data access to the local associated chargers or storage facilities as needed. A remote site1519can be emplaced at facilities without sufficient wired data capability. In such an environment, a long-range wireless connection1520(e.g., a wireless system such as point-to-point microwave or a public (or private) cellular data network) provides connectivity a via secure internal network1521to the local administration system1522as well as to (in this example) the combined inventory and telemetry server1523. A local wireless LAN1524provides local connectivity between the secure local network1521and dismounted battery packs (not shown) held in storage at the remote site1519. One example of such a remote site1519is at an exchange-only depot with no (or insufficient, or expensive) charging power available, and thus no charge cradles are equipped at the site. Inventory information on the supply of ready stocks of battery packs, warehoused depleted battery packs, as well as arrival times of recharged or new battery pack stocks at the remote site1519will be maintained by a local inventory server1522. A secure wireless local area network1525may be used for connection to mobile devices1535requesting local inventory or status information. In addition, wireless remote management terminals1526may connect to the administration center1501via secure wired connections1528and radio messaging1530and via satellite ground stations1527and orbital satellites1529. Depending on permission levels, these remote management terminals1526may request recharging service, request inventory levels at allowed sites, reserve and pre-provision battery packs. The remote management terminals1526also may be used to determine the location of any battery pack or charger in the network via the administration center database1504and GIS capabilities. A secured wired connection1528is supplied to support on-route and mobile terminals that communicate with a continental or global satellite dish network1527. Using a wired datalink connection1528with a continental or global satellite dish network1527with satellite constellation1529, radio messaging1530can be used to connect with a variety of devices including truck Mobile Data Terminals1531, satellite uplink mobiles1532, data tablets1533and satellite radio equipped computers1534. As with the wired management terminal1526, these devices can request services and battery pack status (dependent on permission levels). CONCLUSION Those skilled in the art will appreciate that while the disclosure contained herein pertains to the provision of electrical power to vehicles, it should be understood that this is only one of many possible applications, and other configurations including non-vehicular applications are possible. For example, those skilled in the art will appreciate that there are numerous applications of providing batteries in non-vehicle inductive charging applications such as portable consumer electronic device chargers, such as those (e.g., PowerMat™) used to charge toothbrushes, cellular telephones, and other devices. Large capacity, but still portable, contactless swappable battery packs can be moved, by rail for example, to areas hit by a natural or manmade disaster for crucial electrically powered services. Accordingly, these and other such applications are included within the scope of the following claims. | 74,026 |
11862988 | DETAILED DESCRIPTION In the ensuing description, one or more specific details are illustrated, aimed at providing an in-depth understanding of examples of embodiments of this description. The embodiments may be obtained without one or more of the specific details, or with other methods, components, materials, etc. In other cases, known structures, materials, or operations are not illustrated or described in detail so that certain aspects of embodiments will not be obscured. Reference to “an embodiment” or “one embodiment” in the framework of the present description is intended to indicate that a particular configuration, structure, or characteristic described in relation to the embodiment is comprised in at least one embodiment. Hence, phrases such as “in an embodiment” or “in one embodiment” that may be present in one or more points of the present description do not necessarily refer to one and the same embodiment. Moreover, particular conformations, structures, or characteristics may be combined in any adequate way in one or more embodiments. The references used herein are provided merely for convenience and hence do not define the extent of protection or the scope of the embodiments. The drawings are in simplified form and are not to precise scale. For the sake of simplicity, directional (up/down, etc.) or motional (forward/back, etc.) terms may be used with respect to the drawings. The term “couple” and similar terms do not necessarily denote direct and immediate connections, but also include connections through intermediate elements or devices. One or more embodiments may exploit electromagnetic waves as a power source. For instance, one or more embodiments may be applied to a Radiofrequency (briefly, RF) energy harvester circuit. An RF harvester as exemplified herein may rely on power extracted from RF radio waves as transmitted by a hub or base-station, for instance thanks to a converter circuit. An energy harvester as exemplified herein may thus act as a so-called Radiofrequency-to-Direct-Current (briefly, RF-to-DC) converter. Using RF energy harvesters may be facilitated by the capability of working with (very) low power levels so as to obtain a high operating distance (r) from the power emitting source. Propagation of RF energy may be modelled by means of the Friis equation, which results in power in free space decreasing as r2: PR=PTGTGR(λ/4πr)2PR=PTGTGR(λ/4πr)2 where PRis the power available at the input of the receiving antenna, PTis the output power of the transmitting antenna, GTand GRare the transmitting and receiving antenna gains, respectively, and λ is the wavelength. The lowest RF input power permitting the circuit to convert RF energy into DC is called sensitivity, which is a figure of merit of such circuits. Another performance parameter is the power conversion efficiency (PCE) or simply efficiency, which is a measure of how much of the RF input power Pin is transformed into DC output power Pout, that is: PCE=Pout/Pin. Designing energy harvesters may thus involve: improving sensitivity with the aim of increasing the operating distance; and increasing PCE so that the output power Poutfor a same input power Pinmay be increased. In power generation systems such as RF energy harvesters, RF-to-DC (conversion) efficiency may reach a “best” energy transfer point leading to a highest (maximum) power generation point. The ability to adjust (quickly and precisely) the electrical operation point of the system to maximize efficient power generation may be of interest. Circuit simplicity may be an advantageous feature of a circuit for (ultra) low-power energy harvesting, so that the energy absorbed may be reduced to a level low enough to achieve a positive balance between energy saved and energy taken in a performance improvement function. Throughout the figures, Vin denotes an input line to an energy harvester10adapted to receive an input voltage Vin(t) from an energy source—not visible in the figures. Such an energy source may be, for instance, a radiofrequency source, for instance a radiofrequency (RF) signal having a frequency of 868 MHz, which may be sensed via a receiving antenna RX. The input voltage Vin(t) may be expressed as: Vin(t)=VAsin(ωt) where VAis the amplitude of the ac input signal, co is the angular frequency given by ω=2πf and f is the operating frequency. In one or more embodiments as exemplified inFIG.2, a matching network11may facilitate coupling the antenna RX to the harvester circuit10, facilitating to provide the sensed signal Vin at an input node Vin of the energy harvester. As exemplified inFIG.2, such an energy harvester circuit10may comprise two circuit portions: a power converter circuit section12comprising a first radiofrequency-to-direct-current, RF-to-DC, converter circuit12coupled to the input node Vin and configured to receive the input signal Vin therefrom and to apply RF-to-DC conversion processing thereto, producing a converted signal at an output node Vout; and an energy storage circuit section Cscoupled to the output node Vout of the first RF-to-DC converter circuit12and configured to be supplied with the converted signal Vout therefrom, for instance a capacitor Csconfigured to store energy harvested by the harvester circuit10; and a sensing circuit section14comprising a second RF-to-DC converter circuit14comprising a down-sized replica of the first circuit section12, wherein the second RF-to-DC converter circuit14is configured to receive the first signal at the input node Vin and to produce, at a sensing node Vocs, a scaled converted signal indicative of an open-circuit voltage of the first RF-to-DC circuit section12. One or more embodiments of such an energy harvesting circuit10are discussed in U.S. application for patent Ser. No. 16/849,370 (based on Italian Patent Application n. 102019000006086 filed on Apr. 18, 2019), incorporated by reference. In one or more embodiments, the Voc (open circuit voltage) sensing section14may correspond to a sort of “miniaturized” scaled-down replica of the power section12and provide a measure proportional to the open-circuit voltage Voc (e.g., referred to as Vocs) at a corresponding output node Vocs. In one or more embodiments, the power section12may take the higher percentage of the volume/area of the whole device10and act as the energy generator. For instance, the sensing section14may be a sort of a scaled version, e.g., shrunk in area, of the power section12and which is devoted to measuring the open-circuit voltage Voc. One or more embodiments may use the second RF-to-DC section14as a small “dummy” RF-to-DC cell configured to reproduce the behavior of the “main” RF-to-DC system, with the dummy cell capable of providing, e.g., a measure of the open circuit voltage of the main system which in turn can be used to perform a dynamical system efficiency improvement function. Consequently, the volume/area of the sensing section14may be (much) smaller and almost negligible with respect to the volume/area of the power section12. In the case of a power section12dimensioned to provide 1 μA, this would result in a 1/10 area ratio, that is a scaling factor equal to 10. In one or more embodiments, the ratio of the volume/area of the sensing section14to the volume/area of the power section12will be the (only) source of power inefficiency of the arrangement. For instance, with a proper design of the device10, this inefficiency can be reduced to a minimum, (well) below inefficiency level of conventional solutions. A further increase in energy efficiency may derive from the continuous flow of energy from the device10to the converter, e.g., due to the possibility of avoiding disconnection in order to measure the Voc voltage. Also, the possibility of reducing the size of the system as a whole (system miniaturization) will have a synergistic effect insofar as the additional volume/area taken by the device14will be (largely) compensated by the increase in energy efficiency. In one or more embodiments, as a result, a Volume/Area ratio of the second portion14circuitry may be much lower or better negligible with respect to a Volume/Area ratio of the power section12. In one or more embodiments as exemplified inFIG.2: the first RF-to-DC of the power section12may comprise a first set of N (voltage) converter circuit sub-stages, for instance a set of N multiplier stages, providing a first (for instance, maximum) conversion factor N, for instance N=4, wherein a number of stages Ns in the first converter circuit sub-stages N may be selectively activatable, for instance to provide a certain conversion factor, as discussed in the following; and the second RF-to-DC in the sensing section14may comprise a second set of M (voltage) converter circuit sub-stages, for instance a set of M=N/2 multiplier stages, providing a second (for instance, scaled) conversion factor M, for instance M=N/2=2 when N=4. In one or more embodiments, the ratio between the first multiplication factor and the second multiplication factor may advantageously be of one half, hence providing a reference of half of the open-voltage Voc, e.g., Vocs=Voc/M=Voc/2. The power delivered to a generic load by a Radiofrequency-to-Direct Current (briefly, RF-to-DC) energy converter is dependent on its internal impedance. In particular, Maximum Power Transfer happens if there is a matching between an internal electrical resistance Rs of a RF-to-DC device and a load Rs. RF-to-DC converter circuits convert RF energy into DC electricity proportionally to the (input) power received at the antenna. For instance, the (output) power provided may be expressed as: Pout=(−Vout2+Vout*Voc)/Rs where: Voc is the open circuit output voltage of the RF-to-DC circuit, and Rs is the internal electric resistance of the RF-to-DC. Output power provided by the RF-to-DC circuit versus the output voltage is a parabola having a maximum at the output voltage Vout=Voc/2 which is in turn the same condition obtained by having Rs=RL. This poses a relevant issue during the design phase. The RF-to-DC internal impedance Rs depends on the received power. Hence, in the design phase the power transfer can solely be optimized for a single predefined received power and load condition. Such a condition hardly matches with a real-life situation: in fact, for a defined transmitted power and frequency, in a Wireless Power Transfer, the received power depends very much on the environmental conditions and the distance between the power receiver and transmitter. In general, the received power at the input of the RF-to-DC circuit cannot be considered fixed, as well the load condition is very variable during the power transfer. The system may hence lose efficiency while the relative distance between Power Transmitter and Power Receiver varies or if the environmental conditions changes, as usually happens in practice. FIG.3comprises diagrams exemplary of principles underlying embodiments of the energy harvesting circuit10as exemplified inFIG.2. In one or more embodiments, an open-circuit voltage Voc of the first RF-to-DC section12of the circuit10may vary with respect to input power Pin sensed via at least one antenna RX in an almost linearly growing way, as represented in as exemplified in portion a) ofFIG.3. For instance, a trend of such a quasi-linear curve may be proportional to a number N of sub-stages in the first RF-to-DC circuit section12. In such a considered example: when the input power level Pin has a first power value P1, the open-circuit voltage level Voc has a first voltage value Voc1, wherein such values are coordinate value of such a first operating point of the first RF-to-DC circuit section12in the Voc-Pin diagram as exemplified in portion a) ofFIG.3; and when the input power level Pin has a second power value P2higher than the first power value P1, the open-circuit voltage level Voc has a second voltage value Voc2higher than the first voltage value Voc1, wherein such values are coordinate value of such a second operating point of the first RF-to-DC circuit section12in the Voc-Pin diagram as exemplified in portion a) ofFIG.3. In one or more embodiments as exemplified in portion b) ofFIG.3, an output power Pout vs. output voltage Vout relationship exhibits a substantially (inverted; concave, downwardly facing concavity) parabolic trend with a peak value at Vout=Voc/2, wherein an operative voltage value Vop at which the circuit10is optimized to operate in the design stage is often equal to such a peak value Vout in the expected working conditions, for instance Vout=Voc1/2. In the example considered, following from what discussed with respect to portion a) ofFIG.3, it follows that, as exemplified in portion b) ofFIG.3: when the input power level Pin has a first power value P1, the peak output voltage value is equal to the operative voltage Vop and the circuit has a first efficiency value η1; and when the input power level Pin has a second power value P2higher than the first power value P1, the operative voltage value may be far from the peak output voltage value, as exemplified in portion b) ofFIG.3, leading to the circuit having a second efficiency value η2lower than the first efficiency value η1. A solution according to the present disclosure, provides a method to reconfigure the number of converting sub-stages Ns which may be activated to operate the RF-to-DC conversion in the first RF-to-DC section12so as to solve the problem of loss of efficiency. This may facilitate to avoid wasting positive variations of input power which may arise, for instance, by a reduction of distance between the RF energy source and the sensing antenna RX. This suggests that, in order to facilitate achieving an optimum power transfer, the RF-to-DC cell should desirably be conditioned in order to operate within a voltage range arranged in the vicinity of Voc/2. Facilitating measuring the open-circuit voltage value Voc may hence be helpful. FIG.4comprises diagrams exemplary of principles underlying embodiments of the energy harvesting circuit10as exemplified inFIG.2. In the following, unless otherwise specified, like references may be used to indicate like elements. In one or more embodiments as exemplified inFIG.4, it is observed that the dependency of the trend of the curve between open-circuit voltage Voc of the first RF-to-DC section12of the circuit10and the input power Pin sensed via the at least one antenna RX from the number of activated sub-stages Ns in the set of N sub-stages of the first RF-to-DC section12of the circuit10may be exploited to improve system efficiency. For instance, consider the following scenario in which: until the input power has a first power value P1, all N sub-stages of the first RF-to-DC section12of the circuit10operate the conversion of the received signal Vin to the converted signal Vout, wherein the circuit section12with all N sub-stages activated has an first open-circuit voltage Voc1(detectable thanks to the second RF-to-DC converter14); and when the input power increases, reaching a second power value P2higher than the first power value P1, a reduced number Ns, for instance Ns=N/2, of all N sub-stages of the first RF-to-DC section12are selectively activated, wherein as a result of the number of active substages being Ns, wherein the second open circuit voltage Voc2(detectable thanks to the second RF-to-DC converter14) may be equal to the first open-circuit voltage Voc1as a result as exemplified in portion a) ofFIG.4. In such a considered example: when the input power level Pin has a first power value P1, the open-circuit voltage level Voc has a first voltage value Voc1, wherein such values are coordinate value of such a first operating point of the first RF-to-DC circuit section12in the Voc-Pin diagram as exemplified in portion a) ofFIG.4; and when the input power level Pin has a second power value P2higher than the first power value P1, the open-circuit voltage level Voc has a second voltage value Voc2equal to the first voltage value Voc1, wherein such values are coordinate value of such a second operating point of the first RF-to-DC circuit section12in the Voc-Pin diagram as exemplified in portion a) ofFIG.4. In one or more embodiments as exemplified in portion b) ofFIG.4, the peak value at Vout=Voc/2 remains constant throughout different input-power value ranges, so that the operative voltage value Vop at which the circuit10is optimized to operate in the design stage remains the one of the working conditions expected by design, for instance Vout=Voc1/2=Voc2/2=Vop. In the example considered, following from what discussed with respect to portion a) ofFIG.4, it follows that, as exemplified in portion b) ofFIG.4: when the input power level Pin has the first power value P1, the peak output voltage value is equal to the operative voltage Vop and the circuit has a first efficiency value111as exemplified in portion b) ofFIG.3; and when the input power level Pin has a second power value P2higher than the first power value P1, the operative voltage value remains close or equal to the peak output voltage value Vop. As a result, the circuit10operated in such a way shows an improved performance, adjustability and flexibility, without loss of efficiency in terms of energy conversion. FIG.5is a further exemplary diagram of principles underlying embodiments, wherein the number of active stages may be varied in a plurality of operating conditions, for instance: until the input power has a first power value P1, all N sub-stages of the first RF-to-DC section12of the circuit10operate the conversion of the received signal Vin to the converted signal Vout, wherein the circuit section12with all N sub-stages activated has an first open-circuit voltage Voc1(detectable thanks to the second RF-to-DC converter14); when the input power increases, reaching a second power value P2higher than the first power value P1, a reduced number Ns, for instance Ns=N/2, of all N sub-stages of the first RF-to-DC section12are selectively activated, wherein as a result of the number of active substages being Ns, wherein the second open circuit voltage Voc2(detectable thanks to the second RF-to-DC converter14) may be equal to the first open-circuit voltage Voc1as a result; and when the input power further increases, reaching a third power value P3higher than both the first power value P1and the second power value P2, a further reduced number, for instance N/3, of all N sub-stages of the first RF-to-DC section12are selectively activated, wherein as a result of the number of active substages being reduced to N/3, a third open circuit voltage Voc3=Voc1=Voc2(detectable thanks to the second RF-to-DC converter14) may be equal to the first open-circuit voltage Voc1. In one or more embodiments as exemplified inFIG.6, a configurable energy harvesting circuit100as per the present disclosure may comprise: a harvester circuit10, as discussed in the foregoing. The circuit100also includes a driver circuitry20coupled to said first and second RF-to-DC sections12,14, the driver circuitry comprising a voltage reference (Vref) circuit section200and configured to receive said sensing signal Vocs from said second RF-to-DC section14and to selectively activate/deactivate a number Ns of sub-stages in the set of sub-stages of the first RF-to-DC section12. A load stage ZLcomprising a load impedance element is coupled between the first voltage node Vout of the first RF-to-DC converter and ground GND. In one or more embodiments, the driver circuitry20may comprise: the voltage reference section200formed, for instance, by a voltage reference generator, for instance a low-dropout (LDO) voltage regulator, the generator200configured to provide a voltage operative level at a respective voltage reference node Vop, for instance the voltage operative level at which the operation of the first RF-to-DC is designed to optimally function. The driver circuitry20further includes a window comparator stage202,204configured to determine whether the open-circuit voltage sensed Vocs at the sensing node Vocs of the second RF-to-DC is above or below the reference voltage level threshold, wherein the comparator202,204is configured to output at a respective first node Up a first binary signal Up which may have a first value, for instance a “logical high” or “1”, if Vocs is greater than a threshold value, e.g. Vocs>Vop, or a second value, for instance a “logical low” or “0”, if Vocs is lower or equal than the threshold value, e.g. Vocs<Vop, and, at a respective second node Dn, a second binary signal Dn which may have a first value, for instance a “logical high” or “1”, if Vocs is lower than a threshold value, e.g. Vocs>>Vop, or a second value, for instance a “logical low” or “0”, if Vocs is greater or equal than the threshold value, e.g. Vocs<Vop. A finite state machine (FSM) stage21, preferably an asynchronous FSM, is coupled to said window comparator and configured to receive the first and second binary signals Up, Dn and to apply FSM processing thereto, producing a control signal cbs (for instance, a control bit sequence) which may be provided to the first RF-to-DC conversion stage, wherein the control signal cbs is configured to selectively activate/deactivate the set of sub-stages Ns in all N substages of the first RF-to-DC section12. In one or more embodiments, employing an asynchronous FSM21may facilitate reducing power losses with respect to employing a synchronous FSM21, the first advantageously avoiding the employ of a power consuming clock generator. In one or more embodiments, as discussed in the following, the control signal cbs may be a two-bit (or n-bit) signal whose value may be a function of an operational state of the FSM stage21and of the binary signals Up, Dn input thereto, for instance cbs may be computed as a summation of binary signals Up, Dn. In one or more embodiments, the window comparator202,204may comprise: i) a first “over-voltage” comparator circuit202, e.g. a hysteresis comparator, having a first “positive” input node coupled to the sensing node Vocs of the second RF-to-DC section12and configured to receive the (scaled) sensed open-circuit voltage level Vocs therefrom, the first comparator stage202having a second “negative” input node coupled to the reference voltage node Vop and configured to receive the voltage reference level Vop therefrom; and ii) a second “under-voltage” comparator circuit204, e.g. a hysteresis comparator, having a first “negative” input node coupled to the sensing node Vocs of the second RF-to-DC section12and configured to receive the (scaled) sensed open-circuit voltage level Vocs therefrom, the first comparator stage202having a second “positive” input node coupled to the reference voltage node Vop and configured to receive the voltage reference level Vop therefrom. Each of the first and second comparator circuits202,204detects the common input voltage Vocs against reference voltages ±Vocs as upper and lower limits. In one or more embodiments, the driver circuitry21may comprise a power on reset (POR) circuit section207coupled to the FSM circuit21and configured to reset an operational state of the FSM, as discussed in the following. One or more embodiments may optionally comprise a further comparator circuit208having a first “positive” node coupled to the output node of the first RF-to-DC section12and configured to receive the first output voltage Vout therefrom and having a second “negative” input node coupled to the reference generator200and configured to receive the voltage reference level Vop therefrom, the further comparator208being coupled to the load stage ZLand configured to control the load ZL, for instance controlling an activation status of the load as a function of the output voltage being proportional to the operative voltage Vop. In one or more embodiments, the further comparator208may comprise a simple (low-cost) ultra-low-power comparator which may condition the voltage stored at CLin order to facilitate its average to approximate the operative voltage value Vop voltage in various environmental conditions, as discussed in the following (see, for instance,FIG.8). FIG.7is an exemplary state diagram of possible functioning of the FSM circuit21in one or more embodiments. Considering an exemplary scenario, wherein the first RF-to-DC section12comprises a number of N=6 sub-stages and wherein the second RF-to-DC section14comprises M=N/2=3 sub-stages, as exemplified inFIG.7, for instance: a POR signal may be sent by the POR stage207to the FSM stage21, initializing it to a start state212. In the start state212, as long as the open-circuit voltage Vocs sensed at the sensing node Vocs of the second RF-to-DC section14is within a first interval ±Vop, which may be indicative of the input power level condition Pin=P1, the control signal cbs may have a start value, for instance cbs=“00” which may selectively activate the maximum number Ns of substages in the first RF-to-DC section12, for instance Ns=N=6. The FSM21may envisage a first transition from the start state212to a first state214, wherein the first transition may be triggered as a result of an increase of the value of the open-circuit voltage Vocs sensed at the sensing node Vocs of the second RF-to-DC section14, for instance Vocs=Voc2>Vop, wherein such an increase condition may be detected as a result of the comparator212,214outputting a signal Up having the first value, for instance when Up=“1”, which may be indicative of the input power level condition Pin=P2. In the first state214, the control signal cbs may have a first value, for instance cbs=“01”, and a reduced (for instance, halved) number of substages may be activated/deactivated as a result, for instance Ns=N/2=3. The FSM21may further have a second transition from the first state214to a second state216, wherein the second transition may be triggered as a result of a further increase of the value of the open-circuit voltage Vocs sensed at the sensing node Vocs of the second RF-to-DC section14, for instance Vocs=Voc3>Vop, wherein such an increase condition may be detected as a result of the comparator212,214outputting a signal Up having the first value, for instance when Up=“1”, while the system is in the first state214, which may be indicative of the input power level condition Pin=P3. In the second state216, the control signal cbs may have a second value, for instance cbs=“10”, and a reduced (for instance, one-third of the total) number of substages Ns may be activated/deactivated as a result, for instance Ns=N/3=2. The FSM21may further transition from the second state216to a third state218, wherein the further transition may be triggered as a result of another increase of the value of the open-circuit voltage Vocs sensed at the sensing node Vocs of the second RF-to-DC section14, wherein such an increase condition may be detected as a result of the comparator212,214outputting another signal Up having the first value, for instance when Up=“1”, while the system is in the third state216, which may be indicative of the input power level condition Pin>P3. In the third state218, the control signal cbs may have a third value, for instance cbs=“11”, and a reduced (for instance, one-sixth of the total) number of substages Ns may be activated/deactivated as a result, for instance Ns=N/6=1. In one or more embodiments, while in any of the states212,214,216,218, the FSM21may envisage opposed transitions going in an opposite direction with respect to what discussed in the foregoing, as a result of the comparator212,214outputting a signal Dn having the first value, for instance when Dn=“1”, while the system is any of the state212,214,216,218, causing a change in the control signal value, for instance from cbs=“11” to cbs=“10”, which may be indicative of the input power level condition Pin<=P3. In one or more embodiments as exemplified inFIG.8, for instance in a steady-state condition, the voltage Vout provided by the first RF-to-DC section12and stored on the element CLmay toggle between two voltages Vh and Vl. For instance, as a result of Vout reaching an (upper) voltage Vh, a transfer mechanism of the energy stored at16can be activated towards a load ZL(see the right-hand side ofFIG.6), which per se may be distinct from the embodiments, e.g., an IoT node, with the load ZLcoupled to an output node18cof the third comparator208. In one or more embodiments as exemplified inFIG.2, energy transfer towards the load ZLmay be, e.g., via a DC-DC converter (which per se may be of a conventional, simplified design) controlled via a signal output by the third comparator208. As a result of energy being transferred to the load, the voltage Vout may drop from an upper value Vh (see again the diagram ofFIG.8) to a lower value Vl, with the DC-DC converter turned off (energy transfer discontinued), thereby facilitating renewed storage of energy until the upper value Vh is reached again. As mentioned, in one or more embodiments voltage drop from Vh to Vl may be limited, e.g., in such a way that the average of voltage Vout may approximate the “desired” operative voltage Vop, advantageously providing dynamically improved energy conversion efficiency. As exemplified inFIG.8, the system may alternate between a charge phase and a discharge phase with a frequency proportional to the input power. For instance, the higher the input power, the shorter the charge phase period, leading to a higher commutation frequency. In battery-free sensor applications, for instance such as BLE radio, data is transmitted whenever a discharge phase is initiated, the higher the commutation frequency between charge/discharge phases, the higher the data transmission rate may advantageously be increased. One or more embodiments may advantageously increase the amount of data which may be transmitted, for a given amount of input power, by a sensor powered with a harvester as per the present disclosure, facilitating approximating real-time systems data rates. For instance, for a given circuit10, Vh and Vl can be selected so that Vh=Voc/2+ΔV and Vl=Voc/2−ΔV with (Vh+Vl)/2=Voc, with ΔV selected in such a way that power loss with respect to the highest value is maintained within a desired range (e.g., 90%). In one or more embodiments as exemplified inFIG.6, the FSM stage21may be coupled to the voltage reference source200and may be configured for controllably varying its value in order to compensate for possible non-linearities which may arise in Pout-Vout curves of the circuit10with very high levels of input power Pin. FIG.9is an exemplary diagram of such non-linearities. For instance, when the input power Pin is much higher than P3, it may be convenient to raise or lower the value of Vop to facilitate selecting a condition which may lead to conserving a possibly highest efficiency value, e.g., a first Vop′ may be set for Ns′=6, respectively, Ns″=6, without varying the reference voltage generator level if the input power Pin is average or much higher than P3, respectively. For instance, when the input power Pin is much higher than P3, it may be convenient to further scale down also the down-sized version14of the first RF-to-DC converter, in order to facilitate selecting a condition which may lead to conserving a possibly highest efficiency value. In one or more embodiments, a limited range of power values may be set for the system to operate within. For instance, the range may comprise an upper and a lower limiting values, wherein the lower value may be determined as a function of the maximum number N of sub-stages, which may contribute to improving device sensitivity, while the upper limit may be determined as a function of a “minimum” number of substages which may be active at the same time. In one or more embodiments, an electrically powered system, optionally battery-less electrically powered system (e.g., a mobile RF terminal or a wireless sensor comprising at least one RF sensing antenna RX) may include an energy harvester circuit10as exemplified herein, for instance as a source of electrical power supply. As exemplified herein, an energy harvester circuit (for instance,100) may comprise: a first radiofrequency-to-direct current, RF-to-DC, circuit section (for instance,12) configured to receive a first signal from at least one radiofrequency sensing antenna (for instance, RX) at a first node (for instance, Vin) and to produce a first converted signal at a second node (for instance, Vout); an energy storage circuit section (for instance, CO coupled to the first RF-to-DC section and supplied with the converted signal therefrom; a second RF-to-DC circuit section (for instance,14) comprising a down-scaled replica of the first RF-to-DC section and configured to receive said first converted signal at said input node and to produce, at a sensing node (for instance, Vocs), a second converted signal indicative of an open-circuit voltage of the first RF-to-DC circuit section; driver circuitry (for instance,20) comprising a voltage reference generator (for instance,200) configured to provide a voltage reference signal (for instance, Vop) and coupled to said first and second RF-to-DC converter circuits (for instance,12,14); wherein said first RF-to-DC section comprises a number N of integer sub-stages, at least one sub-set of integer sub-stages in said number N of integer sub-stages being selectively deactivatable/activatable (for instance, Ns). The driver circuitry is configured to: i) perform a comparison (for instance,212,214) between said second converted signal and said voltage reference signal, wherein said comparison produces a first signal (for instance, Up) and a second signal (for instance, Dn), the first signal (Up) having a first value when said second converted signal is higher than said voltage reference signal and the second signal having a first value when said second converted signal is lower said voltage reference signal in order to check whether the second converted signal is within a range of values (for instance, Up, Dn) proportional to said voltage reference signal and ii) selectively deactivate (for instance,21, cbs), respectively activate, a sub-set of integer sub-stages (for instance, Ns) in said number N of integer sub-stages of said first RF-to-DC section when said performed comparison has a first result, respectively a second result. As exemplified herein, the first RF-to-DC circuit section may comprise a first voltage multiplier comprising a plurality of multiplication sub-stages (for instance, Ns), the first voltage multiplier having a unitary minimum multiplication factor and a maximum multiplication factor of N, wherein the multiplication factor may be varies selectively as a function of the integer number of multiplication substages activated in the range between unity and N. As exemplified herein, said down-scaled replica of the first RF-to-DC section of the second RF-to-DC circuit section may have a scaling factor equal to two, providing a half-scaled replica of the first RF-to-DC section. As exemplified herein, the driver circuitry may comprise a window comparator (for instance,212,214) coupled to the voltage reference generator and to the second RF-to-DC circuit section, the comparator being sensitive to the voltage reference signal received from the generator (200) and to the second signal from the second RF-to-DC circuit section. As exemplified herein, the comparator may comprise a first (for instance,212) and a second (for instance,214) hysteresis comparators configured to change state at an upper end and a lower end of a hysteresis interval around said voltage reference signal, respectively. As exemplified herein, said driver circuitry may comprise a finite state machine, FSM, circuit (for instance,21) configured to receive said first signal and said second signal, the FSM circuit configured to produce and provide to said first RF-to-DC section12a control signal (for instance, cbs) configured to selectively activate, respectively deactivate, said sub-set of integer sub-stages in said number N of integer sub-stages of said first RF-to-DC section when said performed comparison has a first result, respectively a second result, the FSM circuit preferably comprising an asynchronous FSM circuit. As exemplified herein, a system may comprise: at least one radiofrequency antenna (for instance, RX) configured to sense a RF signal (for instance, Vin); at least one circuit (for instance,100) as exemplified herein, the circuit having said first RF-to-DC circuit section and said second RF-to-DC circuit section coupled (for instance,11) to said at least one radiofrequency antenna to receive therefrom said first signal; and an electrical load (for instance, ZL) coupled to the output node of the circuit (for instance,10) to be supplied thereby. As exemplified herein, the system may comprise a matching network (for instance,11) configured to adaptively couple at least one radiofrequency antenna with said first RF-to-DC circuit section and said second RF-to-DC circuit section. As exemplified herein, said electrical load may be an electrically powered sensor device. As exemplified herein, a method (for instance,21) of operating a circuit (100), comprises: performing a comparison (for instance,212,214) between said second converted signal (for instance, Vocs) and said voltage reference signal (for instance, Vop), wherein said comparison produces a first signal (for instance, Up) and a second signal (for instance, Dn), the first signal having a first value when said second converted signal is higher than said voltage reference signal and the second signal having a first value when said second converted signal is lower than said voltage reference signal in order to check whether the second converted signal is within a range of values (for instance, Up, Dn) proportional to said voltage reference signal; and selectively deactivating (for instance,21, cbs), respectively activating, a sub-set of integer sub-stages (for instance, Ns) in said number N of integer sub-stages of said first RF-to-DC section when said performed comparison has a first result, respectively a second result. It will be otherwise understood that the various individual implementing options exemplified throughout the figures accompanying this description are not necessarily intended to be adopted in the same combinations exemplified in the figures. One or more embodiments may thus adopt these (otherwise non-mandatory) options individually and/or in different combinations with respect to the combination exemplified in the accompanying figures. The claims are an integral part of the technical teaching provided herein with reference to the embodiments. Without prejudice to the underlying principles, the details and embodiments may vary, even significantly, with respect to what has been described by way of example only, without departing from the extent of protection. The extent of protection is defined by the annexed claims. | 39,149 |
11862989 | DETAILED DESCRIPTION Detailed embodiments of the claimed structures and methods are disclosed herein; however, it can be understood that the disclosed embodiments are merely illustrative of the claimed structures and methods that may be embodied in various forms. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments. Embodiments of the present invention relate to the field of computing, and more particularly to a computerized method for solar power utilization and management. The following described exemplary embodiments provide a system, method, and program product to, among other things, enable solar power recharging of a mobile device when a direct source of the solar power is obstructed due to weather or other physical conditions. Therefore, the present embodiment has the capacity to improve the technical field of managing power of mobile devices by enabling solar charging when a direct solar source is obstructed. As previously described, shifting from fossil fuels to electrical power systems are accelerating worldwide. Many mobile devices such as vehicles, ships and drones utilize electrical operation based on solar battery sources. Power optimization is essential for long running battery-operated devices. In many cases, mobile devices lack frequent access points for charging. The lack of charging locations is even more pronounced for flying mobile devices such as drones. Due to changing weather, or other physical obstacles, battery recharging or operation under solar energy may be impinged when there are obstructions affecting a solar charging or operation-equipped device. For example, due to cloud formations, a drone may have little or no direct sunlight available for a solar cell and, thus, unable to adequately replenish expended battery energy. In addition, when the drone is above a body of water, the drone cannot perform an emergency landing in the event of full battery depletion. As such, it may be advantageous to, among other things, implement a system capable of recharging depleted battery energy by focusing equipped solar cells toward objects with low diffusion, such a body of water, in order to more effectively optimize available solar energy for battery recharging. In at least one other embodiment, the system may utilize an ad hoc network of one or more unmanned vehicles within a preconfigured radius to reflect available solar rays toward the device, thus enable recharging or continuous operation of the mobile device, such as unmanned aerial vehicle (UAV), when direct solar energy is unavailable. Typically, reflection ratio of solar radiation from a surface is a function of surface smoothness and angle of sunlight. Specular reflection occurs when solar light falls on the surface and reflects off in a single outgoing direction. A mirror presents an example of reflecting light in a single direction. On the other hand, when light rays are reflected in multiple directions, then diffuse, reflection occurs resulting in the reflected solar radiation being unusable. The smoothness of a body that reflects solar radiation, such as a water surface, may be affected by environmental factors, such as wind speed and wind direction. For example, high wind speed may cause more disturbances on water and, therefore, may reduce the smoothness of the surface. This results in higher diffusion rate of a solar radiation. According to one embodiment, a device may determine that power level of a battery may be below a threshold level and requires immediate, and possibly emergency, recharging through equipped solar panels. Captured weather, geolocation, and environmental data may be analyzed and, after identifying one or more nearby objects with low diffusion, utilizing the light emission from the one or more objects that may be reflected, either directly or indirectly, using other mobile devices in order to maximize the recharging energy of the mobile device requiring a recharge. The present invention may be a system, a method, and/or a computer program product at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. These computer readable program instructions may be provided to a processor of a computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. The following described exemplary embodiments provide a system, method, and program product to enable recharging of a mobile device using solar energy when a direct source (i.e., the sun) is obstructed. Referring toFIG.1, an exemplary networked computer environment100is depicted, according to at least one embodiment. The networked computer environment100may include mobile device102and a server112interconnected via a communication network114. According to at least one implementation, the networked computer environment100may include a plurality of mobile devices102and servers112, of which only one of each is shown for illustrative brevity. The communication network114may include various types of communication networks, such as a wide area network (WAN), local area network (LAN), a telecommunication network, a wireless network, a public switched network and/or a satellite network. The communication network114may include connections, such as wire, wireless communication links, or fiber optic cables. It may be appreciated thatFIG.1provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements. Mobile device102may include a processor104and a data storage device106that are connected or attached to a geolocation device122, imaging device124, solar cell126and light reflecting device128and is enabled to host and run a software program108and a solar power management (SPM) program110A and communicate with the server112via the communication network114, in accordance with one embodiment of the invention. Mobile device102may be, for example, a mobile device, a mobile telephone, a personal digital assistant, a netbook, a laptop computer, a tablet computer, a drone, an electrical moving device, or any type of computing device capable of hosting and controlling one or more of the geolocation device122, imaging device124, solar cell126and light reflecting device128while running a program and accessing a network. As will be discussed with reference toFIG.4, the mobile device102may include internal components402aand external components404a, respectively. For example, mobile device102may be a mobile phone that has a solar cell122that may receive a light reflected from a light reflecting device of a drone in order to charge the battery. According to an example embodiment, the geolocation device122may be a Global Positioning System (GPS) device that is based on a global navigation satellite system, or any other device that may receive a radio signal and determine a location of the mobile device using triangulation. The imaging device124, may be a camera or other image capturing device that may capture a photograph of a surrounding space in order to analyze the surface for determination of light sources or light reflecting objects. The solar cell126may be any type of device that is capable of transforming solar radiation, such as light, into an electrical current for charging an onboard battery installed on mobile device102or operating the mobile device102. According to an example embodiment, the solar cell126may incorporate one or more servo engines or other devices capable of angling, rotating and/or otherwise positioning a solar cell126placed on any directional surface of the mobile device102in order to maximize the transformation of the solar energy into the electrical current. The light reflecting device128may be a movable light reflector, such as a mirror or any other device capable of reflecting and focusing the solar energy into a specific direction. The light reflecting device128, may be a standalone device, a part of the solar cell126or integrated into the solar cell126. For example, the solar cell126may have a partially reflecting surface thus allowing it to convert part of the light into electricity and reflecting the rest to the requested direction. The server112may be a laptop computer, netbook computer, personal computer (PC), a desktop computer, or any programmable electronic device or any network of programmable electronic devices capable of hosting and running a solar power management (SPM) program110B and a storage device116with geolocation data118and environmental data120. The server112is communicating with the mobile device102via the communication network114, in accordance with embodiments of the invention. As will be discussed with reference toFIG.4, the server112may include internal components402band external components404b, respectively. The server112may also operate in a cloud computing service model, such as Software as a Service (SaaS), Platform as a Service (PaaS), or Infrastructure as a Service (IaaS). The server112may also be located in a cloud computing deployment model, such as a private cloud, community cloud, public cloud, or hybrid cloud. The geolocation data118may store all of the current locations of the one or more mobile devices, such as mobile device102, that are received from geolocation device122via communication network114. The one or more mobile devices utilized to provide recharging assistance through the SPM program110A,110B may be owned and operated as part of a vehicle fleet with a common owner or have opted in to the SPM program110A,110B through a user opt-in procedure. The environmental data120may include weather conditions in the space area of the mobile device102, such as clouds, wind speed, and wind direction, water bodies and other light-emitting and reflecting objects, such as glass buildings or reflecting roofs. According to an example embodiment, the environmental data120may be limited in the area while the space area may be determined as a sphere or a hemisphere having a radius not more than a visibility range at the location of the mobile device102. According to the present embodiment, the SPM program110A,110B may be a program capable of identifying an object with low diffusion that may be used directly or through other mobile devices in order to transmit the solar energy from the object to a solar panel of the mobile device in order to recharge or operate the mobile device. The solar power management method is explained in further detail below with respect toFIG.2. Referring now toFIG.2, an operational flowchart illustrating a solar power management process200is depicted according to at least one embodiment. At202, the SPM program110A,110B determines a mobile device requires a solar energy. According to an example embodiment, the SPM program110A,110B may monitor battery levels of all the mobile devices connected to the service and, when one of the mobile devices, such as mobile device102, transmits a signal over the network that the battery level is low, determine that the mobile device requires a recharging. In another embodiment, SPM program110A,110B may determine that the mobile device requires recharging when the mobile device102is unable to use direct solar power after directing solar cell126to a source, such as the sun. For example, the SPM program110A,110B may use imaging device124to capture images and determine that the mobile device102requires a recharging when the power is below a predetermined threshold and no solar power source is identified when analyzing the images from imaging device124. Next, at204, the SPM program110A,110B identifies objects with low diffusion rate. As previously mentioned, diffusion rate may be related to a smoothness of a body or a surface of an area that reflects solar energy, such as a water surface. The diffusion rate of the water surface may be affected by environmental factors, such as wind speed and wind direction. The wind may generate waves on the surface of the water that increase dissipation of the solar light thus having a higher diffusion rate that may not be useful for recharging a mobile device. According to an example embodiment, SPM program110A,110B may receive images from the imaging device124and, using a visual recognition method, identify one or more objects that reflect light from a source or have a low diffusion rate. In another embodiment, SPM program110A,110B may access and search the environmental data120for objects in the space area. In a further embodiment, SPM program110A,110B may use a trained deep neural network to analyze the received images and the environmental data120to identify objects with a low diffusion rate. For example, if the surface area incorporates several water surfaces and buildings having glass panes, the SPM program110A,110B may direct the solar cell126to a light reflection from each of the identified objects to determine a highest electricity generating source. Then, at206, the SPM program110A,110B determines whether the mobile device can recharge directly from the identified objects. According to an example embodiment, when a mobile device102is below the clouds and cannot identify any solar energy reflecting or generating source or a solar energy the mobile device receives using a solar cell126that is directed to the source is below a minimum threshold required for recharging, the SPM program110A,110B determines it cannot recharge directly from the identified objects. For example, if SPM program110A,110B identifies a reflection of the light from the received image after visual recognition processing then the mobile device may charge directly from one or more identified objects. If the SPM program110A,110B can directly recharge from the identified object (step206, “YES” branch), the SPM program110A,110B may continue to step212to recharge the mobile device102. If the SPM program110A,110B determines the mobile device102cannot charge directly from the identified objects (step212, “NO” branch), the SPM program110A,110B may continue to step208to identify other mobile devices in the surface area of the mobile device. Next, at208, in response to determining the mobile device102cannot recharge directly from the identified object, the SPM program110A,110B identifies other mobile devices within a threshold distance of the mobile device. According to an example embodiment, SPM program110A,110B may set a preconfigured spherical distance around the mobile device having a radius equal to the visibility distance acquired from environmental data120. In another embodiment, the SPM program110A,110B may determine a distance based on the imaging device124resolution and/or solar cell126aiming capabilities. For example, if a resolution of the imaging device124does not allow to identify objects further than several miles, the radius will not exceed the maximum resolution limitation. Similarly if a solar sell126has limitations on its movement and aiming, such as servo engines having angling incrementations of two degrees, it may affect aiming of the solar panel to a specific source. In another embodiment, the area may be of any shape or form predetermined by a user, such as cubical or hemispherical. Then, the SPM program110A,110B may identify and control all the mobile devices that were identified in the area and flag them as other mobile devices in the area in the geolocation data118in order to assist with recharging of the mobile device102. Then, at210, the SPM program110A,110B arranges the identified mobile device to reflect the solar energy to the mobile device. According to an example embodiment, the SPM program110A,110B may team together all the identified mobile devices in the area of the mobile device by causing the identified mobile devices to relocate to a position that resembles a chain in order to reflect the solar energy from the object with low diffusion rate, through an associated light reflecting device128associated with each identified mobile device, to the mobile device that requires a recharging, as depicted inFIG.3. For example, the SPM program110A,110B may arrange the plurality of other mobile devices in the space to reflect the solar radiation by positioning the plurality of other mobile devices in a chain structure that reflects the solar radiation from the identified object using the light reflecting device of a first mobile device towards the light reflecting device of a second mobile device which in turn reflects the solar radiation to the solar cell of the mobile device. The optimal distance between the mobile devices and their relative location may be determined using a trained neural network that receives, as inputs, a voltage generated by the solar cells and location of each of the identified mobile devices. For example, if mobile devices are drones and one of the drones is under clouds and cannot directly charge from the sunlight, other drones that are in the area may arrange in a chain and, by reflecting and refocusing light from a water source, provide the requested solar power to the drone that requested recharging. In further embodiments, the distance between the identified mobile devices in the chain may be determined based on most efficient solar energy transfer when the maximum distance between each of two mobile devices may be determined based on a surface area of the solar cell126and an area of the reflected light that may be determined using imaging device124, such as that all the reflected light will be within the most efficient range of the solar cell. In another embodiment, the SPM program110A,110B may control the identified mobile devices reflect the solar energy to the mobile device that requires recharging using a solar energy generator that is incorporated in that device. Next, at212, the SPM program110A,110B recharges the mobile device. According to an example embodiment, the SPM program110A,110B may instruct the mobile device that requires a recharge to align the solar cell126to the solar energy source such as either to the closest identified mobile device or to the closest object having a low emission rate. According to an example embodiment, the SPM program110A,110B may maintain the recharging of the mobile device until a battery of the mobile device reaches a threshold. The threshold for recharging may be determined by a user or based on determination what is a minimum battery charge for the mobile device102to reach a recharging location. In further embodiment, the SPM program110A,110B may charge the mobile device102until the batteries are fully charged. FIG.3depicting an operation of the solar power management process according to at least one embodiment. The mobile device102, according to an example embodiment, is in need of a battery charge through solar cell126but sufficient solar radiation is obstructed by clouds306and a direct charge using solar radiation304is unavailable. In this scenario, SPM program110A,110B may utilizing objects with low diffusion coefficient, such as a body of water308, and other unmanned aerial vehicles302in order to deliver solar radiation for recharging of mobile device102. It may be appreciated thatFIGS.2and3provide only an illustration of one implementation and do not imply any limitations with regard to how different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements. According to one embodiment, in response to the SPM program110A,110B determining that the mobile device102can recharge directly without needing other mobile devices and multiple identified objects are present, the SPM program110A,110B may calculate a position at which an optimal amount of reflected light is received by the solar cell126. For example, if the SPM program110A,110B identifies three objects, such as nearby bodies of water, with satisfactory diffusion rates, the SPM program110A,110B may position the solar cell at an angle and direction toward all three bodies of water so that the light received is most optimal for recharging even though optimal light from any single body of water may not be received at that position. In another embodiment, if one of the identified mobile devices have a light source, the SPM program110A,110B may cause the light source of the identified mobile device to emit the light on a solar cell126of the mobile device102to recharge it when no other solar radiation is available. FIG.3depicting an operation of the solar power management process according to at least one embodiment. The mobile device102, according to an example embodiment, is in need of a battery charge through solar cell126but sufficient solar radiation is obstructed by clouds306and a direct charge using solar energy304is unavailable. In this scenario, SPM program110A,110B may utilizing objects with low diffusion coefficient, such as a body of water308, and other unmanned aerial vehicles302in order to deliver solar energy for recharging of mobile device102. FIG.4is a block diagram400of internal and external components of the mobile device102and the server112depicted inFIG.1in accordance with an embodiment of the present invention. It should be appreciated thatFIG.4provide only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements. The data processing system402,404is representative of any electronic device capable of executing machine-readable program instructions. The data processing system402,404may be representative of a smart phone, a computer system, PDA, or other electronic devices. Examples of computing systems, environments, and/or configurations that may represented by the data processing system402,404include, but are not limited to, personal computer systems, server systems, thin clients, thick clients, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, network PCs, minicomputer systems, and distributed cloud computing environments that include any of the above systems or devices. The mobile device102and the server112may include respective sets of internal components402a,b and external components404a,b illustrated inFIG.4. Each of the sets of internal components402include one or more processors420, one or more computer-readable RAMs422, and one or more computer-readable ROMs424on one or more buses426, and one or more operating systems428and one or more computer-readable tangible storage devices430. The one or more operating systems428, the software program108and the SPM program110A in the mobile device102, and the SPM program110B in the server112are stored on one or more of the respective computer-readable tangible storage devices430for execution by one or more of the respective processors420via one or more of the respective RAMs422(which typically include cache memory). In the embodiment illustrated inFIG.4, each of the computer-readable tangible storage devices430is a magnetic disk storage device of an internal hard drive. Alternatively, each of the computer-readable tangible storage devices430is a semiconductor storage device such as ROM424, EPROM, flash memory or any other computer-readable tangible storage device that can store a computer program and digital information. Each set of internal components402a,b also includes a R/W drive or interface432to read from and write to one or more portable computer-readable tangible storage devices438such as a CD-ROM, DVD, memory stick, magnetic tape, magnetic disk, optical disk or semiconductor storage device. A software program, such as the SPM110A,110B, can be stored on one or more of the respective portable computer-readable tangible storage devices438, read via the respective R/W drive or interface432, and loaded into the respective hard drive430. Each set of internal components402a,b also includes network adapters or interfaces436such as a TCP/IP adapter cards, wireless Wi-Fi interface cards, or 3G or 4G wireless interface cards or other wired or wireless communication links. The software program108and the SPM program110A in the mobile device102and the SPM program110B in the server112can be downloaded to the mobile device102and the server112from an external computer via a network (for example, the Internet, a local area network or other, wide area network) and respective network adapters or interfaces436. From the network adapters or interfaces436, the software program108and the SPM program110A in the mobile device102and the SPM program110B in the server112are loaded into the respective hard drive430. The network may comprise copper wires, optical fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. Each of the sets of external components404a,b can include a computer display monitor444, a keyboard442, and a computer mouse434. External components404a,b can also include touch screens, virtual keyboards, touch pads, pointing devices, and other human interface devices. Each of the sets of internal components402a,b also includes device drivers440to interface to computer display monitor444, keyboard442, and computer mouse434. The device drivers440, R/W drive or interface432, and network adapter or interface436comprise hardware and software (stored in storage device430and/or ROM424). It is understood in advance that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed. Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models. Characteristics are as follows: On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service's provider. Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs). Resource pooling: the provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time. Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported providing transparency for both the provider and consumer of the utilized service. Service Models are as follows: Software as a Service (SaaS): the capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based e-mail). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings. Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations. Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls). Deployment Models are as follows: Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises. Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises. Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services. Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds). A cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure comprising a network of interconnected nodes. Referring now toFIG.5, illustrative cloud computing environment50is depicted. As shown, cloud computing environment50comprises one or more cloud computing nodes100with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone54A, desktop computer54B, laptop computer54C, and/or automobile computer system54N may communicate. Nodes100may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment50to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices54A-N shown inFIG.5are intended to be illustrative only and that computing nodes100and cloud computing environment50can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser). Referring now toFIG.6, a set of functional abstraction layers500provided by cloud computing environment50is shown. It should be understood in advance that the components, layers, and functions shown inFIG.5are intended to be illustrative only and embodiments of the invention are not limited thereto. As depicted, the following layers and corresponding functions are provided: Hardware and software layer60includes hardware and software components. Examples of hardware components include: mainframes61; RISC (Reduced Instruction Set Computer) architecture based servers62; servers63; blade servers64; storage devices65; and networks and networking components66. In some embodiments, software components include network application server software67and database software68. Virtualization layer70provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers71; virtual storage72; virtual networks73, including virtual private networks; virtual applications and operating systems74; and virtual clients75. In one example, management layer80may provide the functions described below. Resource provisioning81provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and Pricing82provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may comprise application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. User portal83provides access to the cloud computing environment for consumers and system administrators. Service level management84provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment85provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA. Workloads layer90provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation91; software development and lifecycle management92; virtual classroom education delivery93; data analytics processing94; transaction processing95; and solar power management96. Solar power management96may relate to enabling recharging of a mobile device by transmitting solar energy using other mobile devices from an object that reflects the solar energy in the instances when the mobile device is unable to charge directly from the source of the solar energy due to obstacles. The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. | 42,569 |
11862990 | DETAILED DESCRIPTION Hereinafter, various embodiments of the disclosure will be described in detail with reference to the accompanying drawings. FIG.1is a block diagram illustrating an electronic device101in a network environment100according to certain embodiments. Referring toFIG.1, the electronic device101in the network environment100may communicate with an electronic device102via a first network198(e.g., a short-range wireless communication network), or an electronic device104or a server108via a second network199(e.g., a long-range wireless communication network). According to an embodiment, the electronic device101may communicate with the electronic device104via the server108. According to an embodiment, the electronic device101may include a processor120, memory130, an input device150, a sound output device155, a display device160, an audio module170, a sensor module176, an interface177, a haptic module179, a camera module180, a power management module188, a battery189, a communication module190, a subscriber identification module (SIM)196, or an antenna module197. In some embodiments, at least one (e.g., the display device160or the camera module180) of the components may be omitted from the electronic device101, or one or more other components may be added in the electronic device101. In some embodiments, some of the components may be implemented as single integrated circuitry. For example, the sensor module176(e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) may be implemented as embedded in the display device160(e.g., a display). The processor120may execute, for example, software (e.g., a program140) to control at least one other component (e.g., a hardware or software component) of the electronic device101coupled with the processor120, and may perform certain data processing or computation. According to an embodiment, as at least part of the data processing or computation, the processor120may load a command or data received from another component (e.g., the sensor module176or the communication module190) in volatile memory132, process the command or the data stored in the volatile memory132, and store resulting data in non-volatile memory134. According to an embodiment, the processor120may include a main processor121(e.g., a central processing unit (CPU) or an application processor (AP)), and an auxiliary processor123(e.g., a graphics processing unit (GPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with, the main processor121. Additionally or alternatively, the auxiliary processor123may be adapted to consume less power than the main processor121, or to be specific to a specified function. The auxiliary processor123may be implemented as separate from, or as part of the main processor121. The auxiliary processor123may control at least some of functions or states related to at least one component (e.g., the display device160, the sensor module176, or the communication module190) among the components of the electronic device101, instead of the main processor121while the main processor121is in an inactive (e.g., sleep) state, or together with the main processor121while the main processor121is in an active state (e.g., executing an application). According to an embodiment, the auxiliary processor123(e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., the camera module180or the communication module190) functionally related to the auxiliary processor123. The memory130may store certain data used by at least one component (e.g., the processor120or the sensor module176) of the electronic device101. The certain data may include, for example, software (e.g., the program140) and input data or output data for a command related thereto. The memory130may include the volatile memory132or the non-volatile memory134. The program140may be stored in the memory130as software, and may include, for example, an operating system (OS)142, middleware144, or an application146. The input device150may receive a command or data to be used by other component (e.g., the processor120) of the electronic device101, from the outside (e.g., a user) of the electronic device101. The input device150may include, for example, a microphone, a mouse, or a keyboard. The sound output device155may output sound signals to the outside of the electronic device101. The sound output device155may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing record, and the receiver may be used for an incoming calls. According to an embodiment, the receiver may be implemented as separate from, or as part of the speaker. The display device160may visually provide information to the outside (e.g., a user) of the electronic device101. The display device160may include, for example, a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector. According to an embodiment, the display device160may include touch circuitry adapted to detect a touch, or sensor circuitry (e.g., a pressure sensor) adapted to measure the intensity of force incurred by the touch. The audio module170may convert a sound into an electrical signal and vice versa. According to an embodiment, the audio module170may obtain the sound via the input device150, or output the sound via the sound output device155or a headphone of an external electronic device (e.g., an electronic device102) directly (e.g., wiredly) or wirelessly coupled with the electronic device101. The sensor module176may detect an operational state (e.g., power or temperature) of the electronic device101or an environmental state (e.g., a state of a user) external to the electronic device101, and then generate an electrical signal or data value corresponding to the detected state. According to an embodiment, the sensor module176may include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor. The interface177may support one or more specified protocols to be used for the electronic device101to be coupled with the external electronic device (e.g., the electronic device102) directly (e.g., wiredly) or wirelessly. According to an embodiment, the interface177may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface. A connecting terminal178may include a connector via which the electronic device101may be physically connected with the external electronic device (e.g., the electronic device102). According to an embodiment, the connecting terminal178may include, for example, a HDMI connector, a USB connector, a SD card connector, or an audio connector (e.g., a headphone connector). The haptic module179may convert an electrical signal into a mechanical stimulus (e.g., a vibration or a movement) or electrical stimulus which may be recognized by a user via his tactile sensation or kinesthetic sensation. According to an embodiment, the haptic module179may include, for example, a motor, a piezoelectric element, or an electric stimulator. The camera module180may capture a still image or moving images. According to an embodiment, the camera module180may include one or more lenses, image sensors, image signal processors, or flashes. The power management module188may manage power supplied to the electronic device101. According to an embodiment, the power management module188may be implemented as at least part of, for example, a power management integrated circuit (PMIC). The battery189may supply power to at least one component of the electronic device101. According to an embodiment, the battery189may include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell. The communication module190may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device101and the external electronic device (e.g., the electronic device102, the electronic device104, or the server108) and performing communication via the established communication channel. The communication module190may include one or more communication processors that are operable independently from the processor120(e.g., the application processor (AP)) and supports a direct (e.g., wired) communication or a wireless communication. According to an embodiment, the communication module190may include a wireless communication module192(e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module194(e.g., a local area network (LAN) communication module or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device via the first network198(e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network199(e.g., a long-range communication network, such as a cellular network, the Internet, or a computer network (e.g., LAN or wide area network (WAN)). These certain types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module192may identify and authenticate the electronic device101in a communication network, such as the first network198or the second network199, using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the subscriber identification module196. The antenna module197may transmit/receive a signal or power to/from an external entity (e.g., an external electronic device). According to some embodiments, the antenna module197may be formed of a conductor or a conductive pattern and may further include any other component (e.g., RFIC). According to an embodiment, the antenna module197may include one or more antennas, which may be selected to be suitable for a communication scheme used in a specific communication network, such as the first network198or the second network199by, for example, the communication module190. Through the selected at least one antenna, a signal or power may be transmitted or received between the communication module190and the external electronic device. At least some of the above-described components may be coupled mutually and communicate signals (e.g., commands or data) therebetween via an inter-peripheral communication scheme (e.g., a bus, general purpose input and output (GPIO), serial peripheral interface (SPI), or mobile industry processor interface (MIPI)). According to an embodiment, commands or data may be transmitted or received between the electronic device101and the external electronic device104via the server108coupled with the second network199. Each of the electronic devices102and104may be a device of a same type as, or a different type, from the electronic device101. According to an embodiment, all or some of operations to be executed at the electronic device101may be executed at one or more of the external electronic devices102,104, or108. For example, if the electronic device101should perform a function or a service automatically, or in response to a request from a user or another device, the electronic device101, instead of, or in addition to, executing the function or the service, may request the one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and transfer an outcome of the performing to the electronic device101. The electronic device101may provide the outcome, with or without further processing of the outcome, as at least part of a reply to the request. To that end, a cloud computing, distributed computing, or client-server computing technology may be used, for example. FIG.2is a block diagram200illustrating the power management module188and the battery189according to various embodiments. Referring toFIG.2, the power management module188may include charging circuitry210, a power adjuster220, or a power gauge230. The charging circuitry210may charge the battery189by using power supplied from an external power source outside the electronic device101. According to an embodiment, the charging circuitry210may select a charging scheme (e.g., normal charging or quick charging) based at least in part on a type of the external power source (e.g., a power outlet, a USB, or wireless charging), magnitude of power suppliable from the external power source (e.g., about 20 Watt or more), or an attribute of the battery189, and may charge the battery189using the selected charging scheme. The external power source may be connected with the electronic device101, for example, directly via the connecting terminal178or wirelessly via the antenna module197. The power adjuster220may generate a plurality of powers having different voltage levels or different current levels by adjusting a voltage level or a current level of the power supplied from the external power source or the battery189. The power adjuster220may adjust the voltage level or the current level of the power supplied from the external power source or the battery189into a different voltage level or current level appropriate for each of some of the components included in the electronic device101. According to an embodiment, the power adjuster220may be implemented in the form of a low drop out (LDO) regulator or a switching regulator. The power gauge230may measure use state information about the battery189(e.g., a capacity, a number of times of charging or discharging, a voltage, or a temperature of the battery189). The power management module188may determine, using, for example, the charging circuitry210, the power adjuster220, or the power gauge230, charging state information (e.g., lifetime, over voltage, low voltage, over current, over charge, over discharge, overheat, short, or swelling) related to the charging of the battery189based at least in part on the measured use state information about the battery189. The power management module188may determine whether the state of the battery189is normal or abnormal based at least in part on the determined charging state information. If the state of the battery189is determined to abnormal, the power management module188may adjust the charging of the battery189(e.g., reduce the charging current or voltage, or stop the charging). According to an embodiment, at least some of the functions of the power management module188may be performed by an external control device (e.g., the processor120). The battery189, according to an embodiment, may include a protection circuit module (PCM)240. The PCM240may perform one or more of various functions (e.g., a pre-cutoff function) to prevent a performance deterioration of, or a damage to, the battery189. The PCM240, additionally or alternatively, may be configured as at least part of a battery management system (BMS) capable of performing various functions including cell balancing, measurement of battery capacity, count of a number of charging or discharging, measurement of temperature, or measurement of voltage. According to an embodiment, at least part of the charging state information or use state information regarding the battery189may be measured using a corresponding sensor (e.g., a temperature sensor) of the sensor module176, the power gauge230, or the power management module188. According to an embodiment, the corresponding sensor (e.g., a temperature sensor) of the sensor module176may be included as part of the PCM240, or may be disposed near the battery189as a separate device. The electronic device according to certain embodiments may be one of certain types of electronic devices. The electronic devices may include, for example, a portable communication device (e.g., a smart phone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. According to an embodiment of the disclosure, the electronic devices are not limited to those described above. It should be appreciated that certain embodiments of the present disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include certain changes, equivalents, or replacements for a corresponding embodiment. With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements. It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise. As used herein, each of such phrases as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C,” may include all possible combinations of the items enumerated together in a corresponding one of the phrases. As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element. As used herein, the term “module” may include a unit implemented in hardware, software, or firmware, and may interchangeably be used with other terms, for example, “logic,” “logic block,” “part,” or “circuitry”. A module may be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, according to an embodiment, the module may be implemented in a form of an application-specific integrated circuit (ASIC). Certain embodiments as set forth herein may be implemented as software (e.g., the program140) including one or more instructions that are stored in a storage medium (e.g., internal memory136or external memory138) that is readable by a machine (e.g., the electronic device101). For example, a processor (e.g., the processor120) of the machine (e.g., the electronic device101) may invoke at least one of the one or more instructions stored in the storage medium, and execute it, with or without using one or more other components under the control of the processor. This allows the machine to be operated to perform at least one function according to the at least one instruction invoked. The one or more instructions may include a code generated by a complier or a code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Wherein, the term “non-transitory” simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. A method according to certain embodiments of the disclosure may be included and provided in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., Play Store™), or between two user devices (e.g., smart phones) directly. If distributed online, at least part of the computer program product may be temporarily generated or at least temporarily stored in the machine-readable storage medium, such as memory of the manufacturer's server, a server of the application store, or a relay server. According to certain embodiments, each component (e.g., a module or a program) of the above-described components may include a single entity or multiple entities. According to certain embodiments, one or more of the above-described components may be omitted, or one or more other components may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, according to certain embodiments, the integrated component may still perform one or more functions of each of the plurality of components in the same or similar manner as they are performed by a corresponding one of the plurality of components before the integration. According to certain embodiments, operations performed by the module, the program, or another component may be carried out sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order or omitted, or one or more other operations may be added. According to various embodiments of the disclosure, connecting an inverter to each of coil groups provided in different layers and charging an electronic device by using a plurality of coils disposed in different layers can improve a charging speed and charging efficiency. FIG.3Ais a diagram schematically illustrating a wireless charging device and an electronic device, according to an embodiment. Referring toFIG.3A, a wireless charging device301(i.e., a wireless charging transmitter) is capable of charging an electronic device302(i.e., a wireless charging receiver) by transmitting power wirelessly. For example, when a battery189of the electronic device302is in a discharged state or has a low level of power, the wireless charging device301may transmit power wirelessly to the electronic device302to charge the battery189. The electronic device302ofFIG.3Amay include the electronic device101shown inFIG.1. The electronic device302may include at least one of a smart phone, a wearable device (e.g., a watch), or a wireless earphone. The wireless charging device301may be identical with or similar to the electronic device302. The wireless charging device301may include at least one of the electronic devices101,102, and104shown inFIG.1. The wireless charging device301may determine the proximity or contact of the electronic device302while waiting for charging of the electronic device302. For example, the wireless charging device301may transmit a ping signal to the electronic device302and thereby determine whether the electronic device302is adjacent to or in contact with the wireless charging device301. In response to the ping signal received from the wireless charging device301, the electronic device302may transmit a feedback signal (e.g., a response signal, identification information, configuration information, and/or a signal strength packet (SSP) signal) to the wireless charging device301. Based on the ping signal used for determining the proximity or contact of the electronic device302, the wireless charging device301may determine whether there is an object (e.g., metal) placed on a housing304of the wireless charging device301. For example, the wireless charging device301may identify a change in electric energy (e.g., current or voltage) measured when transmitting the ping signal and, based on the identified change in electric energy, determine the existence or not of the electronic device302. When the electronic device302exists, the wireless charging device301may adjust at least some of a plurality of parameters related to the ping signal. Above the housing304of the wireless charging device301, a guide (e.g., an indicator) for a position (e.g., a coil position or a chargeable position) in which the electronic device302should be disposed may be displayed. FIG.3Bis a block diagram illustrating a wireless charging environment300of a wireless charging device (i.e., a wireless charging transmitter) and an electronic device (i.e., a wireless charging receiver), according to an embodiment. A wireless charging device301ofFIG.3Bmay be the wireless charging device301shown inFIG.3A. In addition, an electronic device302ofFIG.3Bmay be the electronic device101shown inFIG.1or the electronic device302shown inFIG.3A. When the electronic device302is disposed on a housing304of the wireless charging device301, the wireless charging device301may transmit power wirelessly to the electronic device302to charge a battery321e. The wireless charging device301may include a power transmitter311, a control circuit312, a communication circuit313, and/or a sensing circuit314. The power transmitter311may receive power from an external power source (e.g., a commercial power source, an auxiliary battery device, a laptop computer, a desktop computer, or a smart phone). The power transmitter311may include a power adapter311a, a power generation circuit311b, a matching circuit311c, and a power transmission coil311k. The power adapter311amay convert a voltage of power inputted from an external power source (e.g., a travel adapter (TA)). The power generation circuit311bmay generate power required for power transmission from the converted voltage. The matching circuit311cmay maximize efficiency between the power transmission coil311kand a power reception coil321kof the electronic device302. In case of transmitting power wirelessly to a plurality of electronic devices302, the power transmitter311may include a plurality of power adapters311a, a plurality of power generation circuits311b, a plurality of matching circuits311c, and/or a plurality of power transmission coils311k. The power transmission coil311kmay include a plurality of coils grouped and disposed in different layers. Using the plurality of coils, the wireless charging device301may charge the electronic device302. The control circuit312may perform overall control for transmitting power through the wireless charging device301. The control circuit312may be operatively connected to the power transmitter311, the communication circuit313, and the sensing circuit314. The control circuit312may generate various messages required for wireless power transmission and transmit them to the communication circuit313. The control circuit312may calculate power (or amount of power) to be transmitted to the electronic device302, based on information received from the electronic device302through the communication circuit313. The control circuit312may control the power transmitter311to transmit the calculated power to the electronic device302through the power transmission coil311k. The communication circuit313(e.g., the communication module190inFIG.1) may include at least one of a first communication circuit313aand a second communication circuit313b. The first communication circuit313amay perform communication (e.g., in-band type communication of transmitting a power signal or a communication signal by using the power transmission coil311k) with a first communication circuit323aof the electronic device302, using the same frequency as, or a frequency of a band adjacent to, a frequency used for wireless power transmission by the power transmission coil311k. The second communication circuit313bmay perform communication (e.g., out-band type communication of transmitting a communication signal by using the antenna module197inFIG.1) with a second communication circuit323bof the electronic device302, using a frequency different from a frequency used for wireless power transmission by the power transmission coil311k. The second communication circuit313bmay receive, from the second communication circuit323bof the electronic device302, information, such as information about a rectified voltage (Vrec), information about a current (Iout) flowing in the rectifying circuit, various packets, or messages, about a charging state of the electronic device302by using at least one of, for example, Bluetooth™, Bluetooth™ low energy, Wi-Fi, or near field communication (NFC). The sensing circuit314may include at least one sensor and detect at least one state related to the wireless charging device301by using the at least one sensor. For example, the sensing circuit314may include at least one of a temperature sensor, a motion sensor, a proximity sensor, or a current (or voltage) sensor. The temperature sensor may detect a temperature state of the wireless charging device301. The motion sensor may detect a motion state of the wireless charging device301. The proximity sensor may detect an object (e.g., the electronic device302) in proximity to an upper surface of the housing304of the wireless charging device301. The current (or voltage) sensor may detect an output signal state (e.g., at least one of a current level, a voltage level, or a power level) of the wireless charging device301. The current (or voltage) sensor may measure a signal for the power transmitter311. For example, the current (or voltage) sensor may measure a signal for at least a portion of the matching circuit311cand the power generation circuit311b. The current (or voltage) sensor may include a circuit for measuring a signal for a front end of the power transmission coil311k. The sensing circuit314may detect an external object (e.g., metal) existing between the wireless charging device301and the electronic device302. When the wireless charging device301is a mobile terminal (e.g., a smart phone), the wireless charging device301may include a display160. The wireless charging device301may display, on the display, various kinds of information related to wireless charging, such as information about a charging state of the wireless charging device301, information about a charging state of the electronic device302, information about detection of the electronic device302, or information about detection of an external object (e.g., metal). InFIG.3B, when the electronic device302is disposed above the housing304of the wireless charging device301, the electronic device302may receive power wirelessly from the wireless charging device301. The electronic device302may include at least one of a power receiver321, a control circuit322, a communication circuit323, at least one sensor324, and a display325. In describing components of the electronic device302, the description of components corresponding to those of the wireless charging device301may be omitted. The power receiver321may include at least one of a power reception coil321kfor receiving power wirelessly from the wireless charging device301(especially, from the power transmission coil311k), a matching circuit321a, a rectifying circuit321bfor rectifying received AC power to DC power, an adjusting circuit321cfor adjusting a charging voltage, a switching circuit321d, and/or a battery321e. The control circuit322may perform overall control related to wireless power reception (or wireless charging) of the electronic device302. The control circuit322may generate various kinds of messages related to wireless charging and transmit them to the communication circuit323. The communication circuit323(e.g., the communication module190inFIG.1) may include at least one of a first communication circuit323aand a second communication circuit323b. The first communication circuit323amay perform communication with the first communication circuit313aof the wireless charging device301by using the power reception coil321k. The second communication circuit323bmay perform communication with the second communication circuit313bof the wireless charging device301by using at least one of Bluetooth™, Bluetooth™ low energy, Wi-Fi, or near field communication (NFC). The sensor(s)324may include at least one of a current (or voltage) sensor, a temperature sensor, a proximity sensor, an illuminance sensor, or an acceleration sensor. The display325may display various kinds of information related to wireless power reception (or wireless charging). FIG.3Cis a diagram illustrating operations of a wireless charging device (e.g., a wireless charging transmitter) to detect an object (e.g., metal) of an electronic device (e.g., a wireless charging receiver) according to an embodiment. Referring toFIG.3C, the wireless charging device301may perform a function (e.g., a Tx function) of wirelessly transmitting power to the electronic device302. When the electronic device302is disposed above the housing304shown inFIG.3A, the wireless charging device301may detect and identify the electronic device302and then wirelessly transmit power to the electronic device302. The wireless charging device301may perform a ping operation303, an identification and configuration operation305, and a power transfer operation307. In addition, the wireless charging device301may transmit and receive at least one signal or data by using the ping operation303, the identification and configuration operation305, and the power transfer operation307. Using the ping operation303, a control circuit312of the wireless charging device301may transmit a ping signal in a digital or analog form to the electronic device302. The wireless charging device301may receive a feedback signal (e.g., a response signal, identification information, configuration information, and/or SSP signal) in response to the ping signal from the electronic device302, and detect whether the electronic device302exists. In the ping operation303, the control circuit312of the wireless charging device301may set a plurality of parameters related to transmission of the ping signal. For example, the control circuit312of the wireless charging device301may set a plurality of parameters related to at least one of a frequency of the ping signal, a voltage applied to a power transmission circuit (e.g., the power transmitter311or the power transmission coil311k) to transmit the ping signal, or a transmission period of the ping signal. The plurality of parameters may be provided as default values in the initial setting of the wireless charging device301. In the ping operation303, the control circuit312of the wireless charging device301may determine whether there is an object (e.g., metal) above the wireless charging device301. The control circuit312of the wireless charging device301may transmit a ping signal based on a plurality of parameters related to transmission of the ping signal during an operation period (or a wireless charging standby state) related to the ping operation303, and identify electric energy (e.g., at least one of current and voltage) measured by the power transmitter311(or the power transmission coil311k) in response to the ping signal transmission. The control circuit312of the wireless charging device301may identify at least one of a relationship between a voltage measured by the power transmitter311(or the power transmission coil311k) in response to the ping signal transmission and a predetermined threshold voltage or a relationship between a current measured by the power transmitter311(or the power transmission coil311k) and a predetermined threshold current, and determine the existence or not of an object above the wireless charging device301, based on the identifying result. The control circuit312of the wireless charging device301may detect a state of an object (e.g., the type of the object, the size of the object, or the arrangement of the object), or a change in such a state, existing above the wireless charging device301, based on a change in electric energy (e.g., at least one of current and voltage) measured by the power transmitter311(or the power transmission coil311k) in response to the ping signal transmission. When there is an object (e.g., metal) above the wireless charging device301, the control circuit312of the wireless charging device301may change or adjust at least some of the plurality of parameters related to transmission of the ping signal so as to suppress noise due to the object (e.g., vibration of the object and/or noise in the audible frequency band due to such vibration), heat generation of the object, or the deterioration of the wireless charging device301caused by the object (e.g., heat generation of the wireless charging device301caused by induction heating from the object). The control circuit312of the wireless charging device301may output a specified notification (e.g., light emission, vibration, or sound) in order to provide a notification about the existence of the object. Upon detecting the electronic device302(i.e., a wireless charging receiver), the control circuit312of the wireless charging device301may receive identification information and configuration information of the electronic device302in the identification and configuration operation305. The identification information may include at least one kind of information (e.g., a wireless communication ID of the electronic device302) for identifying the electronic device302. When the identification information is identical with information (e.g., a wireless communication ID of the electronic device302for which wireless power sharing with the wireless charging device301is authenticated) previously stored in a memory130, the control circuit312of the wireless charging device301may determine the detected electronic device302as a valid device. The configuration information may include various kinds of information required for the electronic device302to receive power wirelessly from the wireless charging device301. As the electronic device302is authenticated based on the identification information and the configuration information, the control circuit312of the wireless charging device301may wirelessly transmit power to the electronic device302in the power transfer operation307. In the power transfer operation307, the control circuit312of the wireless charging device301may receive, from the electronic device302, at least one control error packet (CEP) signal having notification information about power (or amount of power) required by the electronic device302for charging, and/or a received power packet (RPP) signal having size information about power (or amount of power) received by the electronic device302. The control circuit312of the wireless charging device301may adjust power wirelessly transmitted to the electronic device302, based on the at least one CEP signal and/or the RPP signal. According to an embodiment, the electronic device302may transmit the at least one CEP signal and/or the RPP signal at regular time intervals or when a specific event (e.g., a state change of the electronic device302) occurs. The at least one CEP signal and the RRP signal may be transmitted at different time intervals. FIG.4is a diagram illustrating a configuration of a plurality of coils provided in a wireless charging device according to an embodiment. Referring toFIG.4, a wireless charging device301(i.e., a wireless charging transmitter) may include a first group of coils401(hereinafter, a first coil group), a second group of coils402(hereinafter, a second coil group), and/or a third group of coils403(hereinafter, a third coil group) within a housing304. Each of the first coil group401, the second coil group402, and the third coil group403may include the power transmission coil311kshown inFIG.3B. The first coil group401, the second coil group402, and the third coil group403may be disposed in different layers. Each of the first coil group401, the second coil group402, and the third coil group403may be formed of one layer. Alternatively, each of the first coil group401, the second coil group402, and the third coil group403may be formed of a plurality of layers instead of one layer. The first coil group401may be disposed in a first layer (e.g., an upper layer) above the second coil group402. The first coil group401may include a plurality of coils. For example, the first coil group401may include a first coil411and a second coil413. The first coil411and the second coil413may be disposed in the same layer or different layers. The second coil group402may be disposed in a second layer (e.g., an intermediate layer) under the first coil group401. The second coil group402may include a plurality of coils. The second coil group402may include a third coil421, a fourth coil423, a fifth coil425, and a sixth coil427. The third coil421, the fourth coil423, the fifth coil425, and the sixth coil427may be disposed in the same layer or different layers. The third coil group403may be disposed in a third layer (e.g., a lower layer) under the second coil group403. The third coil group403may include a plurality of coils. The third coil group403may include a seventh coil431, an eighth coil433, a ninth coil435, and a tenth coil437. The seventh coil431, the eighth coil433, the ninth coil435, and the tenth coil437may be disposed in the same layer or different layers. A central axis of each of the first coil411and the second coil413in the first coil group401disposed in the first layer may not coincide with a central axis of each of the third coil421, the fourth coil423, the fifth coil425, and the sixth coil427in the second coil group402disposed in the second layer. A central axis of each of the third coil421, the fourth coil423, the fifth coil425, and the sixth coil427in the second coil group402disposed in the second layer may not coincide with a central axis of each of the seventh coil431, the eighth coil433, the ninth coil435, and the tenth coil437in the third coil group403disposed in the third layer. A central axis of each of the first coil411and the second coil413in the first coil group401disposed in the first layer may not coincide with a central axis of each of the seventh coil431, the eighth coil433, the ninth coil435, and the tenth coil437in the third coil group403disposed in the third layer. Although coil grouping is described using the first coil group401to the third coil group403respectively formed in the first layer to the third layer, this is only an example and is not to be construed as a limitation. In one example, a grouping may be formed with coils included in the first coil group401disposed in the first layer. In another example, a grouping may be formed with coils included in the second coil group402and the third coil group403respectively disposed in the second layer and the third layer. That is, in the wireless charging device301as shown inFIG.4, the number of coil groups, the number of layers for coil grouping, and the number of coils included in each coil group are not limited to the examples described herein. FIG.5is a circuit diagram schematically illustrating a configuration of a wireless charging device, according to an embodiment. The wireless charging device501may include a first converter510, a first inverter512, a first switch514, a first coil group401, a first resonant element516, a second converter520, a second inverter522, a second switch524, a second coil group402, a second resonant element526, a third converter530, a third inverter532, a third switch534, a third coil group403, a third resonant element536, and/or a processor540. Referring toFIG.5, the wireless charging device501may receive power from a power supplier505(also referred to as a power supply or power source) that resides outside. The wireless charging device501may be the wireless charging device301described above and shown inFIGS.3A,3B,3C, and/or4. The power supplier505may supply power to the wireless charging device501through a travel adapter (TA) or a universal serial bus (USB). The power supplier505may supply power by converting alternating current (AC) power into direct current (DC) power. The first converter510(e.g., the power adapter311ainFIG.3B) may be electrically connected to the power supplier505. The first converter510may convert DC power, inputted from the power supplier505, into predetermined power. For example, the first converter510may convert a voltage so that an output voltage becomes about 5V. The first inverter512(e.g., the power generation circuit311binFIG.3B) may be electrically connected to the first converter510. The first inverter512may convert a DC voltage, inputted from the first converter510, into an AC voltage. The first inverter512may include an amplifier. When the voltage inputted from the first converter510is less than a predetermined gain, the first inverter512may amplify the voltage to the predetermined gain by using the amplifier. The first switch514may be electrically connected to the first inverter512. The first switch514may form contacts between the first inverter512and the first coil group401. The first switch514may selectively connect the first coil411or the second coil413in the first coil group401to the first inverter512under the control of the processor540. In addition, the first switch514may switch between an on-state and an off-state under the control of the processor540. The first coil group401including the first coil411and the second coil413may be connected to the first inverter512through the first switch514. That is, one of the first coil411and the second coil413may be selectively connected to the first inverter512under the control of the processor540and the ON or OFF operation of the first switch514. One of the first coil411and the second coil413may form an electromagnetic field by AC signals transmitted through the first inverter512under the control of the processor540, thereby transmitting power wirelessly to the electronic device302(i.e., a wireless charging receiver). The first resonant element516may be provided between the first inverter512and the first coil group401. The first resonant element516may comprise a capacitor. The first resonant element516may maximize the efficiency of the first coil group401. The first resonant element516may perform a function of causing a voltage outputted to the electronic device302through the first coil group401to be high voltage with high efficiency. The second converter520(e.g., the power adapter311ainFIG.3B) may be electrically connected to the power supplier505. The second converter520may convert DC power, inputted from the power supplier505, into predetermined power. For example, the second converter520may convert a voltage so that an output voltage becomes about 5V. The second inverter522(e.g., the power generation circuit311binFIG.3B) may be electrically connected to the second converter520. The second inverter522may convert a DC voltage, inputted from the second converter520, into an AC voltage. The second inverter522may include an amplifier. When the voltage inputted from the second converter520is less than a predetermined gain, the second inverter522may amplify the voltage to the predetermined gain by using the amplifier. The second switch524may be electrically connected to the second inverter522. The second switch524may form contacts between the second inverter522and the second coil group402. The second switch524may selectively connect the third coil421, the fourth coil423, the fifth coil425, or the sixth coil427in the second coil group402to the second inverter522under the control of the processor540. In addition, the second switch524may switch between an on-state and an off-state under the control of the processor540. The second coil group402including the third coil421, the fourth coil423, the fifth coil425, and the sixth coil427may be connected to the second inverter522through the second switch524. That is, one of the third coil421, the fourth coil423, the fifth coil425, and the sixth coil427may be selectively connected to the second inverter522under the control of the processor540and the ON or OFF operation of the second switch524. One of the third coil421, the fourth coil423, the fifth coil425, and the sixth coil427may form an electromagnetic field by AC signals transmitted through the second inverter522under the control of the processor540, thereby transmitting power wirelessly to the electronic device302(i.e., a wireless charging receiver). The second resonant element526may be provided between the second inverter522and the second coil group402. The second resonant element526may comprise a capacitor. The second resonant element526may maximize the efficiency of the second coil group402. The second resonant element526may perform a function of causing a voltage outputted to the electronic device302through the second coil group402to be high voltage with high efficiency. The third converter530(e.g., the power adapter311ainFIG.3B) may be electrically connected to the power supplier505. The third converter530may convert DC power, inputted from the power supplier505, into predetermined power. For example, the third converter530may convert a voltage so that an output voltage becomes about 5V. The third inverter532(e.g., the power generation circuit311binFIG.3B) may be electrically connected to the third converter530. The third inverter532may convert a DC voltage, inputted from the third converter530, into an AC voltage. The third inverter532may include an amplifier. When the voltage inputted from the third converter530is less than a predetermined gain, the third inverter532may amplify the voltage to the predetermined gain by using the amplifier. The third switch534may be electrically connected to the third inverter532. The third switch534may form contacts between the third inverter532and the third coil group403. The third switch534may selectively connect the seventh coil431, the eighth coil433, the ninth coil435, or the tenth coil437in the third coil group403to the third inverter532under the control of the processor540. In addition, the third switch534may switch between an on-state and an off-state under the control of the processor540. The third coil group403including the seventh coil431, the eighth coil433, the ninth coil435, and the tenth coil437may be connected to the third inverter532through the third switch534. That is, one of the seventh coil431, the eighth coil433, the ninth coil435, and the tenth coil437may be selectively connected to the third inverter532under the control of the processor540and the ON or OFF operation of the third switch524. One of the seventh coil431, the eighth coil433, the ninth coil435, and the tenth coil437may form an electromagnetic field by AC signals transmitted through the third inverter532under the control of the processor540, thereby transmitting power wirelessly to the electronic device302(i.e., a wireless charging receiver). The third resonant element536may be provided between the third inverter532and the third coil group403. The third resonant element536may comprise a capacitor. The third resonant element536may maximize the efficiency of the third coil group403. The third resonant element536may perform a function of causing a voltage outputted to the electronic device302through the third coil group403to be high voltage with high efficiency. The processor540(e.g., the control circuit312inFIG.3B) may be operatively connected to the first converter510, the first inverter512, the first switch514, the first coil group401, the first resonant element516, the second converter520, the second inverter522, the second switch524, the second coil group402, the second resonant element526, the third converter530, the third inverter532, the third switch534, the third coil group403, and/or the third resonant element536. The processor540may perform overall control of the wireless charging device501. When the electronic device302is adjacent to or in contact with an upper surface of a housing304of the wireless charging device501, the processor540may charge the electronic device302through two coil groups selected from among the first coil group401, the second coil group402, and the third coil group403. When the electronic device302is disposed above (i.e., adjacent to or in contact with) the housing304of the wireless charging device501, the processor540may charge the electronic device302by using one coil (e.g., the first coil411or the second coil413) in the first coil group401and one coil (e.g., the third coil421, the fourth coil423, the fifth coil425, or the sixth coil427) in the second coil group402. When the electronic device302is disposed above (i.e., adjacent to or in contact with) the housing304of the wireless charging device501, the processor540may charge the electronic device302by using one coil (e.g., the first coil411or the second coil413) in the first coil group401, one coil (e.g., the third coil421, the fourth coil423, the fifth coil425, or the sixth coil427) in the second coil group402, and one coil (e.g., the seventh coil431, the eighth coil433, the ninth coil435, or the tenth coil437) in the third coil group403. The processor540may generate various kinds of messages required to wirelessly transmit power to the electronic device302. In addition, the processor540may calculate power or an amount of power to be transmitted to the electronic device302. When the electronic device302is adjacent to or in contact with the wireless charging device501, the processor540may transmit a ping signal to the electronic device302through each of the first coil group401, the second coil group402, and the third coil group403. Then, upon receiving a feedback signal (e.g., signal strength packet (SSP)) returned through each of the first coil group401, the second coil group402, and the third coil group403, the processor540may identify the position of the electronic device302. In order to detect that the electronic device302is adjacent to or in contact with the upper surface of the housing304of the wireless charging device501, the wireless charging device501may measure an impedance change amount of each of the first coil group401, the second coil group402, and the third coil group403in a predetermined time period or in a predetermined measuring pattern. The ping signal may be periodically transmitted to the electronic device302with a certain strength for a certain time. The SSP may contain a predetermined signal having information about voltage strength. The processor540may selectively turn on the first switch514connected to the first inverter512, the second switch524connected to the second inverter522, and/or the third switch534connected to the third inverter532, based on a feedback signal returned from the electronic device302, and also select coils to be operated from among a plurality of coils disposed in respective layers. For example, the plurality of coils may include one coil in the first coil group401disposed in a first layer (e.g., an upper layer), one coil in the second coil group402disposed in a second layer (e.g., an intermediate layer), and one coil in the third coil group403disposed in a third layer (e.g., a lower layer). Based on the feedback signal (e.g., SSP), the processor540may select, as an operating coil, a coil having the largest value from among SSP values. In addition, the processor540may further determine the operating coil in consideration of a ratio of SSP value of each remaining coil to the largest SSP value. The processor540may determine operating voltages of the first inverter512, the second inverter522, and the third inverter532respectively connected to one operating coil in the first coil group401, one operating coil in the second coil group402, and one operating coil in the third coil group403through the first switch514, the second switch524, and the third switch534. The processor540may control pulse width modulation (PWM) signals of the first inverter512, the second inverter522, and the third inverter532to be synchronized with each other or operated independently. The processor540may operate, in the same phase or in different phases, the first inverter512, the second inverter522, and the third inverter532respectively connected to one coil in the first coil group401, one coil in the second coil group402, and one coil in the third coil group403through the first switch514, the second switch524, and the third switch534. The processor540may control the first inverter512, the second inverter522, and/or the third inverter532to generate signals in different frequency bands. In addition, the processor540may control the first coil group401, the second coil group402, and/or the third coil group403to wirelessly transmit different levels of power to the electronic device302. The processor540may control to supply the same voltage or different voltages to the first inverter512, the second inverter522, and the third inverter532. In addition, the processor540may reset the ratio or offset of voltages respectively supplied to the first inverter512, the second inverter522, and the third inverter532, based on the values of currents supplied to the respective inverters. Based on the feedback signal (e.g., SSP), the processor540may set parameters (e.g., at least one of frequency, phase, and voltage) respectively applied to the first coil group401, the second coil group402, and the third coil group403differently through the first inverter512, the second inverter522, and the third inverter532. The first coil group401(e.g., the first coil411and/or the second coil413), the second coil group402(e.g., the third coil421, the fourth coil423, the fifth coil425, and/or the sixth coil427), and the third coil group403(e.g., the seventh coil431, the eighth coil433, the ninth coil435, and/or the tenth coil437) may have the same characteristics or have at least one different characteristic. For example, the characteristics of the coil may include a diameter (e.g., an inner diameter or an outer diameter), a thickness, the number of turns, the number of layers, and/or a coil wound direction. According to an embodiment, a wireless charging device (i.e., a wireless charging transmitter) may include a first inverter, a first switch electrically connected to the first inverter, a second inverter, a second switch electrically connected to the second inverter, a first coil group connected to the first inverter through the first switch, a second coil group connected to the second inverter through the second switch, and a processor operatively connected to the first inverter, the first switch, the second inverter, the second switch, the first coil group, and the second coil group. The processor may be configured to detect an electronic device disposed above the wireless charging device through at least one coil in the first coil group or the second coil group, and to wirelessly transmit power to the electronic device by using one coil (e.g., a first coil or a second coil) in the first coil group and one coil (e.g., one of a third coil, a fourth coil, a fifth coil, and a sixth coil) in the second coil group. The first coil group and the second coil group may be disposed in different layers. A central axis of each of a plurality of coils included in the first coil group may not coincide with a central axis of each of a plurality of coils included in the second coil group. The wireless charging device may further include a first converter for supplying direct current (DC) power to the first inverter, and a second converter for supplying DC power to the second inverter. The wireless charging device501may further include a first resonant element provided between the first inverter and the first coil group, and a second resonant element provided between the second inverter and the second coil group. The wireless charging device may further include a third inverter, a third switch electrically connected to the third inverter, and a third coil group connected to the third inverter through the third switch, and the processor may be configured to detect the electronic device disposed above the wireless charging device through at least one coil in the first coil group, the second coil group, or the third coil group, and to wirelessly transmit power to the electronic device by using one coil in the first coil group, one coil in the second coil group, and one coil in the third coil group. The processor may be configured to transmit a ping signal to the electronic device through each of the first coil group and the second coil group when the electronic device is detected, and to identify a position of the electronic device through a feedback signal (e.g., an SSP signal) returned from the electronic device. The feedback signal may include a signal strength packet (SSP) signal, and the processor may be configured to select, as operating coils, a coil having a largest value of the SSP signal in the first coil group and a coil having a largest value of the SSP signal in the second coil group. The processor may be configured to supply a same voltage or different voltages to the first inverter connected to the first coil group and the second inverter connected to the second coil group. The processor may be configured to control the first inverter connected to the first coil group and the second inverter connected to the second coil group to operate in a same phase or in different phases. FIG.6is a diagram illustrating a charging operation when an electronic device (e.g., a smart phone) is disposed above a wireless charging device, according to an embodiment. Referring toFIG.6, for charging, the electronic device302(i.e., a wireless charging receiver) may be disposed above a housing304of the wireless charging device501(i.e., a wireless charging transmitter). The electronic device302may comprise a smart phone. As shown, the electronic device302may be disposed above the first coil411of the first coil group401disposed in the first layer (e.g., an upper layer) of the wireless charging device501, above the third coil421of the second coil group402disposed in the second layer (e.g., an intermediate layer), and above the eighth coil433of the third coil group403disposed in the third layer (e.g., a lower layer). The processor540of the wireless charging device501may transmit a ping signal to the electronic device302through each of the first coil group401, the second coil group402, and the third coil group403. The processor540of the wireless charging device501may identify the position of the electronic device302, based on a feedback signal (e.g., signal strength packet (SSP)) received through each of the first coil group401, the second coil group402, and the third coil group403. For example, the processor540of the wireless charging device501may receive the feedback signal (e.g., SSP) having a predetermined value or more through the first coil411of the first coil group401, the third coil421of the second coil group402, and the eighth coil433of the third coil group403above which the electronic device302is disposed. Then, based on the received feedback signal, the processor540may identify the position of the electronic device302. The processor540of the wireless charging device501may connect the first inverter512and the first coil411of the first coil group401through the first switch514, connect the second inverter522and the third coil421of the second coil group402through the second switch524, and connect the third inverter532and the eighth coil433of the third coil group403through the third switch534. Using the first coil411of the first coil group401, the third coil421of the second coil group402, and the eighth coil433of the third coil group403, the processor540of the wireless charging device501may output a charging voltage to the electronic device302and thereby perform wireless charging. FIG.7is a diagram illustrating a charging operation when an electronic device (e.g., a watch) is disposed above a wireless charging device according to an embodiment. Referring toFIG.7, for charging, the electronic device302(i.e., a wireless charging receiver) may be disposed above a housing304of the wireless charging device501(i.e., a wireless charging transmitter). The electronic device302may comprise a watch (or a wireless earphone). As shown, the electronic device302may be disposed above the first coil411of the first coil group401disposed in the first layer (e.g., an upper layer) of the wireless charging device501and above the third coil421of the second coil group402disposed in the second layer (e.g., an intermediate layer). The processor540of the wireless charging device501may transmit a ping signal to the electronic device302through each of the first coil group401and the second coil group402. The processor540of the wireless charging device501may receive the feedback signal (e.g., SSP) through the first coil411of the first coil group401and the third coil421of the second coil group402above which the electronic device302is disposed. Then, based on the received feedback signal, the processor540may identify the position of the electronic device302. The processor540of the wireless charging device501may connect the first inverter512and the first coil411of the first coil group401through the first switch514, and connect the second inverter522and the third coil421of the second coil group402through the second switch524. Using the first coil411of the first coil group401and the third coil421of the second coil group402, the processor540of the wireless charging device501may output a charging voltage to the electronic device302and thereby perform wireless charging. FIG.8is a flow diagram illustrating a method for charging an electronic device (i.e., a wireless charging receiver) by using a wireless charging device501(i.e., a wireless charging transmitter), according to an embodiment. The descriptions ofFIG.8are provided for example only, and may include the contents of various embodiments previously described inFIGS.3A to7. At step810, the processor540of the wireless charging device501may detect the electronic device301disposed above the housing304of the wireless charging device. For example, based on a change in impedance of at least one coil (e.g., the first coil401to the tenth coil437), the processor540may detect that an object (e.g., the electronic device301) is disposed above the wireless charging device501. At step820, the processor540of the wireless charging device501may transmit a ping signal to the electronic device302through each of the first coil group401, the second coil group402, and the third coil group403. For example, the processor540may transmit the ping signals through the first to tenth coils401to437. At step830, the processor540of the wireless charging device501may receive a feedback signal (e.g., a signal strength packet (SSP)) for the ping signal from the electronic device302, and thereby identify the position of the electronic device302. For example, the electronic device302may transmit different feedback signals for the ping signals respectively received from the first to tenth coils401to437. At step840, based on the position of the electronic device302, the processor540of the wireless charging device501may connect at least one coil (e.g., the first coil411to the tenth coil437) included in at least one coil group (e.g., the first coil group401, the second coil group402, and the third coil group403) to the first inverters512to the third inverters532by using the first switch514to the third switch534. For example, the processor540of the wireless charging device501may connect one coil (e.g., the first coil411) in the first coil group401to the first inverter512through the first switch514, and connect one coil (e.g., the third coil421) in the second coil group402to the second inverter522through the second switch524. At step850, the processor540of the wireless charging device501may output a charging voltage to the electronic device302by using one coil (e.g., the first coil411) in the first coil group401and one coil (e.g., the third coil421) in the second coil group402), and thereby perform wireless charging. According to an embodiment, a method for charging an electronic device by using a wireless charging device (i.e., a wireless charging transmitter) may include, at a processor of the wireless charging device, detecting the electronic device through at least one coil in a first coil group or a second coil group; at the processor, transmitting a ping signal to the electronic device through each of the first coil group and the second coil group; at the processor, identifying a position of the electronic device upon receiving a feedback signal for the ping signal from the electronic device; at the processor, connecting a first inverter and one coil in the first coil group through a first switch and connecting a second inverter and one coil in the second coil group through a second switch; and at the processor, wirelessly transmitting power to the electronic device by using the one coil in the first coil group and the one coil in the second coil group. The first coil group and the second coil group may be disposed in different layers. A central axis of each of a plurality of coils included in the first coil group may not coincide with a central axis of each of a plurality of coils included in the second coil group. The wireless charging device may include a first converter for supplying direct current (DC) power to the first inverter, and a second converter for supplying DC power to the second inverter. The wireless charging device may include a first resonant element provided between the first inverter and the first coil group, and a second resonant element provided between the second inverter and the second coil group. The wireless charging device may include a third inverter, a third switch electrically connected to the third inverter, and a third coil group connected to the third inverter through the third switch, and when the electronic device is detected, an output voltage may be outputted to the electronic device by using one coil in the first coil group, one coil in the second coil group, and one coil in the third coil group. The wireless charging device may include a third resonant element provided between the third inverter and the third coil group. The feedback signal may include a signal strength packet (SSP) signal, and a coil having a largest value of the SSP signal in the first coil group and a coil having a largest value of the SSP signal in the second coil group may be selected as operating coils. A same voltage or different voltages may be supplied to the first inverter connected to the first coil group and the second inverter connected to the second coil group. The first inverter connected to the first coil group and the second inverter connected to the second coil group may operate in a same phase or in different phases. While the disclosure has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the subject matter as defined by the appended claims. | 71,660 |
11862991 | While the following detailed description will be given with respect to certain illustrative embodiments, it should be understood that the drawings are not necessarily to scale and the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In addition, in certain instances, details which are not necessary for an understanding of the disclosed subject matter or which render other details too difficult to perceive may have been omitted. It should therefore be understood that this disclosure is not limited to the particular embodiments disclosed and illustrated herein, but rather to a fair reading of the entire disclosure and claims, as well as any equivalents thereto. Additional, different, or fewer components and methods may be included in the systems and methods. DETAILED DESCRIPTION In the following description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. Referring now to the drawings and with specific reference toFIG.1, a wireless power transfer system10is illustrated. The wireless power transfer system10provides for the wireless transmission of electrical signals, such as, but not limited to, electrical energy, electrical power, electrical power signals, electromagnetic energy, and electronically transmittable data (“electronic data”). As used herein, the term “electrical power signal” refers to an electrical signal transmitted specifically to provide meaningful electrical energy for charging and/or directly powering a load, whereas the term “electronic data signal” refers to an electrical signal that is utilized to convey data across a medium. The wireless power transfer system10provides for the wireless transmission of electrical signals via near field magnetic coupling. As shown in the embodiment ofFIG.1, the wireless power transfer system10includes one or more wireless transmission systems20and one or more wireless receiver systems30. A wireless receiver system30is configured to receive electrical signals from, at least, a wireless transmission system20. As illustrated, the wireless transmission system(s)20and wireless receiver system(s)30may be configured to transmit electrical signals across, at least, a separation distance or gap17. A separation distance or gap, such as the gap17, in the context of a wireless power transfer system, such as the system10, does not include a physical connection, such as a wired connection. There may be intermediary objects located in a separation distance or gap, such as, but not limited to, air, a counter top, a casing for an electronic device, a plastic filament, an insulator, a mechanical wall, among other things; however, there is no physical, electrical connection at such a separation distance or gap. Thus, the combination of two or more wireless transmission systems20and wireless receiver system30create an electrical connection without the need for a physical connection. As used herein, the term “electrical connection” refers to any facilitation of a transfer of an electrical current, voltage, and/or power from a first location, device, component, and/or source to a second location, device, component, and/or destination. An “electrical connection” may be a physical connection, such as, but not limited to, a wire, a trace, a via, among other physical electrical connections, connecting a first location, device, component, and/or source to a second location, device, component, and/or destination. Additionally or alternatively, an “electrical connection” may be a wireless power and/or data transfer, such as, but not limited to, magnetic, electromagnetic, resonant, and/or inductive field, among other wireless power and/or data transfers, connecting a first location, device, component, and/or source to a second location, device, component, and/or destination. Further, whileFIGS.1-2may depict wireless power signals and wireless data signals transferring only from one antenna (e.g., a transmission antenna21) to another antenna (e.g., a receiver antenna31and/or a transmission antenna21), it is certainly possible that a transmitting antenna21may transfer electrical signals and/or couple with one or more other antennas and transfer, at least in part, components of the output signals or magnetic fields of the transmitting antenna21. Such transmission may include secondary and/or stray coupling or signal transfer to multiple antennas of the system10. In some cases, the gap17may also be referenced as a “Z-Distance,” because, if one considers antennas21,31each to be disposed substantially along respective common X-Y planes, then the distance separating the antennas21,31is the gap in a “Z” or “depth” direction. However, flexible and/or non-planar coils are certainly contemplated by embodiments of the present disclosure and, thus, it is contemplated that the gap17may not be uniform, across an envelope of connection distances between the antennas21,31. It is contemplated that various tunings, configurations, and/or other parameters may alter the possible maximum distance of the gap17, such that electrical transmission from the wireless transmission system20to the wireless receiver system30remains possible. Moreover, in an embodiment, the characteristics of the gap17can change during use, such as by an increase or decrease in distance and/or a change in relative device orientations. The wireless power transfer system10operates when the wireless transmission system20and the wireless receiver system30are coupled. As used herein, the terms “couples,” “coupled,” and “coupling” generally refer to magnetic field coupling, which occurs when a transmitter and/or any components thereof and a receiver and/or any components thereof are coupled to each other through a magnetic field. Such coupling may include coupling, represented by a coupling coefficient (k), that is at least sufficient for an induced electrical power signal, from a transmitter, to be harnessed by a receiver. Coupling of the wireless transmission system20and the wireless receiver system30, in the system10, may be represented by a resonant coupling coefficient of the system10and, for the purposes of wireless power transfer, the coupling coefficient for the system10may be in the range of about 0.01 and 0.9. As illustrated, at least one wireless transmission system20is associated with an input power source12. The input power source12may be operatively associated with a host device, which may be any electrically operated device, circuit board, electronic assembly, dedicated charging device, or any other contemplated electronic device. Example host devices, with which the wireless transmission system20may be associated therewith, include, but are not limited to including, a device that includes an integrated circuit, a portable computing device, storage medium for electronic devices, charging apparatus for one or multiple electronic devices, dedicated electrical charging devices, among other contemplated electronic devices. The input power source12may be or may include one or more electrical storage devices, such as an electrochemical cell, a battery pack, and/or a capacitor, among other storage devices. Additionally or alternatively, the input power source12may be any electrical input source (e.g., any alternating current (AC) or direct current (DC) delivery port) and may include connection apparatus from said electrical input source to the wireless transmission system20(e.g., transformers, regulators, conductive conduits, traces, wires, or equipment, goods, computer, camera, mobile phone, and/or other electrical device connection ports and/or adaptors, such as but not limited to USB ports and/or adaptors, among other contemplated electrical components). Electrical energy received by the wireless transmission system(s)20is then used for at least two purposes: to provide electrical power to internal components of the wireless transmission system20and to provide electrical power to the transmission antenna21. The transmission antenna21is configured to wirelessly transmit the electrical signals conditioned and modified for wireless transmission by the wireless transmission system20via near-field magnetic coupling (NFMC). Near-field magnetic coupling enables the transfer of signals wirelessly through magnetic induction between the transmission antenna21and one or more of receiving antenna31of, or associated with, the wireless receiver system30, another transmission antenna21, or combinations thereof. Near-field magnetic coupling may be and/or be referred to as “inductive coupling,” which, as used herein, is a wireless power transmission technique that utilizes an alternating electromagnetic field to transfer electrical energy between two antennas. Such inductive coupling is the near field wireless transmission of magnetic energy between two magnetically coupled coils that are tuned to resonate at a similar frequency. Accordingly, such near-field magnetic coupling may enable efficient wireless power transmission via resonant transmission of confined magnetic fields. Further, such near-field magnetic coupling may provide connection via “mutual inductance,” which, as defined herein is the production of an electromotive force in a circuit by a change in current in a second circuit magnetically coupled to the first. In one or more embodiments, the inductor coils of either the transmission antenna21or the receiver antenna31are strategically positioned to facilitate reception and/or transmission of wirelessly transferred electrical signals through near field magnetic induction. Antenna operating frequencies may comprise relatively high operating frequency ranges, examples of which may include, but are not limited to, 6.78 MHz (e.g., in accordance with the Rezence and/or Airfuel interface standard and/or any other proprietary interface standard operating at a frequency of 6.78 MHz), 13.56 MHz (e.g., in accordance with the NFC standard, defined by ISO/IEC standard 18092), 27 MHz, and/or an operating frequency of another proprietary operating mode. The operating frequencies of the antennas21,31may be operating frequencies designated by the International Telecommunications Union (ITU) in the Industrial, Scientific, and Medical (ISM) frequency bands, including not limited to 6.78 MHz, 13.56 MHz, and 27 MHz, which are designated for use in wireless power transfer. The transmitting antenna and the receiving antenna of the present disclosure may be configured to transmit and/or receive electrical power having a magnitude that ranges from about 10 milliwatts (mW) to about 500 watts (W). In one or more embodiments the inductor coil of the transmitting antenna21is configured to resonate at a transmitting antenna resonant frequency or within a transmitting antenna resonant frequency band. A “coil” of a wireless power antenna (e.g., the transmission antenna21, the receiver antenna31), as defined herein, is any conductor, wire, or other current carrying material, configured to resonate for the purposes of wireless power transfer and optional wireless data transfer. As known to those skilled in the art, a “resonant frequency” or “resonant frequency band” refers a frequency or frequencies wherein amplitude response of the antenna is at a relative maximum, or, additionally or alternatively, the frequency or frequency band where the capacitive reactance has a magnitude substantially similar to the magnitude of the inductive reactance. In one or more embodiments, the transmitting antenna resonant frequency is at a high frequency, as known to those in the art of wireless power transfer. The wireless receiver system30may be associated with at least one electronic device14, wherein the electronic device14may be any device that requires electrical power for any function and/or for power storage (e.g., via a battery and/or capacitor). Additionally, the electronic device14may be any device capable of receipt of electronically transmissible data. For example, the device may be, but is not limited to being, a handheld computing device, a mobile device, a portable appliance, a computer peripheral, an integrated circuit, an identifiable tag, a kitchen utility device, an electronic tool, an electric vehicle, a game console, a robotic device, a wearable electronic device (e.g., an electronic watch, electronically modified glasses, altered-reality (AR) glasses, virtual reality (VR) glasses, among other things), a portable scanning device, a portable identifying device, a sporting good, an embedded sensor, an Internet of Things (IoT) sensor, IoT enabled clothing, IoT enabled recreational equipment, industrial equipment, medical equipment, a medical device a tablet computing device, a portable control device, a remote controller for an electronic device, a gaming controller, among other things. For the purposes of illustrating the features and characteristics of the disclosed embodiments ofFIGS.1-10, arrow-ended lines are utilized to illustrate transferrable and/or communicative signals and various patterns are used to illustrate electrical signals that are intended for power transmission and electrical signals that are intended for the transmission of data and/or control instructions. Solid lines indicate signal transmission of electrical energy over a physical and/or wireless power transfer, in the form of power signals that are, ultimately, utilized in wireless power transmission from the wireless transmission system20to the wireless receiver system30. Further, dotted lines are utilized to illustrate electronically transmittable data signals, which ultimately may be wirelessly transmitted from the wireless transmission system20to the wireless receiver system30. While the systems and methods herein illustrate the transmission of wirelessly transmitted energy, wireless power signals, wirelessly transmitted power, wirelessly transmitted electromagnetic energy, and/or electronically transmittable data, it is certainly contemplated that the systems, methods, and apparatus disclosed herein may be utilized in the transmission of only one signal, various combinations of two signals, or more than two signals and, further, it is contemplated that the systems, method, and apparatus disclosed herein may be utilized for wireless transmission of other electrical signals in addition to or uniquely in combination with one or more of the above mentioned signals. In some examples, the signal paths of solid or dotted lines may represent a functional signal path, whereas, in practical application, the actual signal is routed through additional components en route to its indicated destination. For example, it may be indicated that a data signal routes from a communications apparatus to another communications apparatus; however, in practical application, the data signal may be routed through an amplifier, then through a transmission antenna, to a receiver antenna, where, on the receiver end, the data signal is decoded by a respective communications device of the receiver. Turning now toFIGS.2-3, the wireless power transfer system10is illustrated as a block diagram including example sub-systems of both the wireless transmission systems20and the wireless receiver systems30. The wireless transmission systems20may include, at least, a power conditioning system40, a transmission control system26, a demodulation circuit70, a transmission tuning system24, and the transmission antenna21. A first portion of the electrical energy input from the input power source12may be configured to electrically power components of the wireless transmission system20such as, but not limited to, the transmission control system26. A second portion of the electrical energy input from the input power source12is conditioned and/or modified for wireless power transmission, to the wireless receiver system30, via the transmission antenna21. Accordingly, the second portion of the input energy is modified and/or conditioned by the power conditioning system40. While not illustrated, it is certainly contemplated that one or both of the first and second portions of the input electrical energy may be modified, conditioned, altered, and/or otherwise changed prior to receipt by the power conditioning system40and/or transmission control system26, by further contemplated subsystems (e.g., a voltage regulator, a current regulator, switching systems, fault systems, safety regulators, among other things). Referring more specifically now toFIG.3, with continued reference toFIGS.1and2, subcomponents and/or systems of the transmission control system26are illustrated. The transmission control system26may include a sensing system50, a transmission controller28, a driver48, a memory27and a demodulation circuit70. The transmission controller28may be any electronic controller or computing system that includes, at least, a processor which performs operations, executes control algorithms, stores data, retrieves data, gathers data, controls and/or provides communication with other components and/or subsystems associated with the wireless transmission system20, and/or performs any other computing or controlling task desired. The transmission controller28may be a single controller or may include more than one controller disposed to control various functions and/or features of the wireless transmission system20. Functionality of the transmission controller28may be implemented in hardware and/or software and may rely on one or more data maps relating to the operation of the wireless transmission system20. To that end, the transmission controller28may be operatively associated with the memory27. The memory may include one or more of internal memory, external memory, and/or remote memory (e.g., a database and/or server operatively connected to the transmission controller28via a network, such as, but not limited to, the Internet). The internal memory and/or external memory may include, but are not limited to including, one or more of a read only memory (ROM), including programmable read-only memory (PROM), erasable programmable read-only memory (EPROM or sometimes but rarely labelled EROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDR SDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data rate synchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5, a flash memory, a portable memory, and the like. Such memory media are examples of nontransitory machine readable and/or computer readable memory media. While particular elements of the transmission control system26are illustrated as independent components and/or circuits (e.g., the driver48, the memory27, the sensing system50, among other contemplated elements) of the transmission control system26, such components may be integrated with the transmission controller28. In some examples, the transmission controller28may be an integrated circuit configured to include functional elements of one or both of the transmission controller28and the wireless transmission system20, generally. As illustrated, the transmission controller28is in operative association, for the purposes of data transmission, receipt, and/or communication, with, at least, the memory27, the power conditioning system40, the driver48, and the sensing system50. The driver48may be implemented to control, at least in part, the operation of the power conditioning system40. In some examples, the driver48may receive instructions from the transmission controller28to generate and/or output a generated pulse width modulation (PWM) signal to the power conditioning system40. In some such examples, the PWM signal may be configured to drive the power conditioning system40to output electrical power as an alternating current signal, having an operating frequency defined by the PWM signal. In some examples, PWM signal may be configured to generate a duty cycle for the AC power signal output by the power conditioning system40. In some such examples, the duty cycle may be configured to be about 50% of a given period of the AC power signal. The sensing system may include one or more sensors, wherein each sensor may be operatively associated with one or more components of the wireless transmission system20and configured to provide information and/or data. The term “sensor” is used in its broadest interpretation to define one or more components operatively associated with the wireless transmission system20that operate to sense functions, conditions, electrical characteristics, operations, and/or operating characteristics of one or more of the wireless transmission system20, the wireless receiving system30, the input power source12, the host device11, the transmission antenna21, the receiver antenna31, along with any other components and/or subcomponents thereof. As illustrated in the embodiment ofFIG.4, the sensing system50may include, but is not limited to including, a thermal sensing system52, an object sensing system54, a receiver sensing system56, a current sensor57, and/or any other sensor(s)58. Within these systems, there may exist even more specific optional additional or alternative sensing systems addressing particular sensing aspects required by an application, such as, but not limited to: a condition-based maintenance sensing system, a performance optimization sensing system, a state-of-charge sensing system, a temperature management sensing system, a component heating sensing system, an IoT sensing system, an energy and/or power management sensing system, an impact detection sensing system, an electrical status sensing system, a speed detection sensing system, a device health sensing system, among others. The object sensing system54, may be a foreign object detection (FOD) system. Each of the thermal sensing system52, the object sensing system54, the receiver sensing system56, the current sensor57and/or the other sensor(s)58, including the optional additional or alternative systems, are operatively and/or communicatively connected to the transmission controller28. The thermal sensing system52is configured to monitor ambient and/or component temperatures within the wireless transmission system20or other elements nearby the wireless transmission system20. The thermal sensing system52may be configured to detect a temperature within the wireless transmission system20and, if the detected temperature exceeds a threshold temperature, the transmission controller28prevents the wireless transmission system20from operating. Such a threshold temperature may be configured for safety considerations, operational considerations, efficiency considerations, and/or any combinations thereof. In a non-limiting example, if, via input from the thermal sensing system52, the transmission controller28determines that the temperature within the wireless transmission system20has increased from an acceptable operating temperature to an undesired operating temperature (e.g., in a non-limiting example, the internal temperature increasing from about 20° Celsius (C) to about 50° C., the transmission controller28prevents the operation of the wireless transmission system20and/or reduces levels of power output from the wireless transmission system20. In some non-limiting examples, the thermal sensing system52may include one or more of a thermocouple, a thermistor, a negative temperature coefficient (NTC) resistor, a resistance temperature detector (RTD), and/or any combinations thereof. As depicted inFIG.4, the transmission sensing system50may include the object sensing system54. The object sensing system54may be configured to detect one or more of the wireless receiver system30and/or the receiver antenna31, thus indicating to the transmission controller28that the receiver system30is proximate to the wireless transmission system20. Additionally or alternatively, the object sensing system54may be configured to detect presence of unwanted objects in contact with or proximate to the wireless transmission system20. In some examples, the object sensing system54is configured to detect the presence of an undesired object. In some such examples, if the transmission controller28, via information provided by the object sensing system54, detects the presence of an undesired object, then the transmission controller28prevents or otherwise modifies operation of the wireless transmission system20. In some examples, the object sensing system54utilizes an impedance change detection scheme, in which the transmission controller28analyzes a change in electrical impedance observed by the transmission antenna20against a known, acceptable electrical impedance value or range of electrical impedance values. Additionally or alternatively, the object sensing system54may utilize a quality factor (Q) change detection scheme, in which the transmission controller28analyzes a change from a known quality factor value or range of quality factor values of the object being detected, such as the receiver antenna31. The “quality factor” or “Q” of an inductor can be defined as (frequency (Hz)×inductance (H))/resistance (ohms), where frequency is the operational frequency of the circuit, inductance is the inductance output of the inductor and resistance is the combination of the radiative and reactive resistances that are internal to the inductor. “Quality factor,” as defined herein, is generally accepted as an index (figure of measure) that measures the efficiency of an apparatus like an antenna, a circuit, or a resonator. In some examples, the object sensing system54may include one or more of an optical sensor, an electro-optical sensor, a Hall Effect sensor, a proximity sensor, and/or any combinations thereof. In some examples, the quality factor measurements, described above, may be performed when the wireless power transfer system10is performing in band communications. The receiver sensing system56is any sensor, circuit, and/or combinations thereof configured to detect a presence of any wireless receiving system that may be couplable with the wireless transmission system20. In some examples, the receiver sensing system56and the object sensing system54may be combined, may share components, and/or may be embodied by one or more common components. In some examples, if the presence of any such wireless receiving system is detected, wireless transmission of electrical energy, electrical power, electromagnetic energy, and/or data by the wireless transmission system20to said wireless receiving system is enabled. In some examples, if the presence of a wireless receiver system is not detected, continued wireless transmission of electrical energy, electrical power, electromagnetic energy, and/or data is prevented from occurring. Accordingly, the receiver sensing system56may include one or more sensors and/or may be operatively associated with one or more sensors that are configured to analyze electrical characteristics within an environment of or proximate to the wireless transmission system20and, based on the electrical characteristics, determine presence of a wireless receiver system30. The current sensor57may be any sensor configured to determine electrical information from an electrical signal, such as a voltage or a current, based on a current reading at the current sensor57. Components of an example current sensor57are further illustrated inFIG.5, which is a block diagram for the current sensor57. The current sensor57may include a transformer51, a rectifier53, and/or a low pass filter55, to process the AC wireless signals, transferred via coupling between the wireless receiver system(s)20and wireless transmission system(s)30, to determine or provide information to derive a current (ITx) or voltage (VTx) at the transmission antenna21. The transformer51may receive the AC wireless signals and either step up or step down the voltage of the AC wireless signal, such that it can properly be processed by the current sensor. The rectifier53may receive the transformed AC wireless signal and rectify the signal, such that any negative voltages remaining in the transformed AC wireless signal are either eliminated or converted to opposite positive voltages, to generate a rectified AC wireless signal. The low pass filter55is configured to receive the rectified AC wireless signal and filter out AC components (e.g., the operating or carrier frequency of the AC wireless signal) of the rectified AC wireless signal, such that a DC voltage is output for the current (ITx) and/or voltage (VTx) at the transmission antenna21. FIG.6is a block diagram for a demodulation circuit70for the wireless transmission system(s)20, which is used by the wireless transmission system20to simplify or decode components of wireless data signals of an alternating current (AC) wireless signal, prior to transmission of the wireless data signal to the transmission controller28. The demodulation circuit includes, at least, a slope detector72and a comparator74. In some examples, the demodulation circuit70includes a set/reset (SR) latch76. In some examples, the demodulation circuit70may be an analog circuit comprised of one or more passive components (e.g., resistors, capacitors, inductors, diodes, among other passive components) and/or one or more active components (e.g., operational amplifiers, logic gates, among other active components). Alternatively, it is contemplated that the demodulation circuit70and some or all of its components may be implemented as an integrated circuit (IC). In either an analog circuit or IC, it is contemplated that the demodulation circuit may be external of the transmission controller28and is configured to provide information associated with wireless data signals transmitted from the wireless receiver system30to the wireless transmission system20. The demodulation circuit70is configured to receive electrical information (e.g., ITx, VTx) from at least one sensor (e.g., a sensor of the sensing system50), detect a change in such electrical information, determine if the change in the electrical information meets or exceeds one of a rise threshold or a fall threshold. If the change exceeds one of the rise threshold or the fall threshold, the demodulation circuit70generates an output signal and also generates and outputs one or more data alerts. Such data alerts are received by the transmitter controller28and decoded by the transmitter controller28to determine the wireless data signals. In other words, in an embodiment, the demodulation circuit70is configured to monitor the slope of an electrical signal (e.g., slope of a voltage signal at the power conditioning system32of a wireless receiver system30) and to output an indication when said slope exceeds a maximum slope threshold or undershoots a minimum slope threshold. Such slope monitoring and/or slope detection by the communications system70is particularly useful when detecting or decoding an amplitude shift keying (ASK) signal that encodes the wireless data signals in-band of the wireless power signal (which is oscillating at the operating frequency). In an ASK signal, as noted above, the wireless data signals are encoded by damping the voltage of the magnetic field between the wireless transmission system20and the wireless receiver system30. Such damping and subsequent re-rising of the voltage in the field is performed based on an underlying encoding scheme for the wireless data signals (e.g., binary coding, Manchester coding, pulse-width modulated coding, among other known or novel coding systems and methods). The receiver of the wireless data signals (e.g., the wireless transmission system20in this example) can then detect rising and falling edges of the voltage of the field and decode said rising and falling edges to demodulate the wireless data signals. Ideally, an ASK signal would rise and fall instantaneously, with no discernable slope between the high voltage and the low voltage for ASK modulation; however, in reality, there is a finite amount of time that passes when the ASK signal transitions from the “high” voltage to the “low” voltage and vice versa. Thus, the voltage or current signal to be sensed by the demodulation circuit70will have some slope or rate of change in voltage when transitioning. By configuring the demodulation circuit70to determine when said slope meets, overshoots and/or undershoots such rise and fall thresholds, established based on the known maximum/minimum slope of the carrier signal at the operating frequency, the demodulation circuit can accurately detect rising and falling edges of the ASK signal. Thus, a relatively inexpensive and/or simplified circuit may be utilized to at least partially decode ASK signals down to notifications or alerts for rising and falling slope instances. As long as the transmission controller28is programmed to understand the coding schema of the ASK modulation, the transmission controller28will expend far less computational resources than would have been needed to decode the leading and falling edges directly from an input current or voltage sense signal from the sensing system50. To that end, as the computational resources required by the transmission controller28to decode the wireless data signals are significantly decreased due to the inclusion of the demodulation circuit70, the demodulation circuit70may significantly reduce BOM of the wireless transmission system20, by allowing usage of cheaper, less computationally capable processor(s) for or with the transmission controller28. The demodulation circuit70may be particularly useful in reducing the computational burden for decoding data signals, at the transmitter controller28, when the ASK wireless data signals are encoded/decoded utilizing a pulse-width encoded ASK signals, in-band of the wireless power signals. A pulse-width encoded ASK signal is a signal wherein the data is encoded as a percentage of a period of a signal. For example, a two-bit pulse width encoded signal may encode a start bit as 20% of a period between high edges of the signal, encode “1” as 40% of a period between high edges of the signal, and encode “0” as 60% of a period between high edges of the signal, to generate a binary encoding format in the pulse width encoding scheme. Thus, as the pulse width encoding relies solely on monitoring rising and falling edges of the ASK signal, the periods between rising times need not be constant and the data signals may be asynchronous or “unclocked.” Examples of pulse width encoding and systems and methods to perform such pulse width encoding are explained in greater detail in U.S. patent application Ser. No. 16/735,342 titled “Systems and Methods for Wireless Power Transfer Including Pulse Width Encoded Data Communications,” to Michael Katz, which is commonly owned by the owner of the instant application and is hereby incorporated by reference in its entirety, for all that it teaches without exclusion of any part thereof. As noted above, slope detection, and hence in-band transfer of data, may become ineffective or inefficient when the signal strength varies from the parameters relied upon during design. For example, when the relative positions of the data sender and data receiver vary significantly during use of the system, the electromagnetic coupling between sender and receiver coils or antennas will also vary. Data detection and decoding are optimized for a particular coupling may fail or underperform at other couplings. As such, a high sensitivity non-saturating detection system is needed to allow the system to operate in environments wherein coupling changes dynamically. For example, referring toFIGS.7, the signal created by the high pass filter71of the slope detector72, prior to being amplified by OPSD, will vary as a result of varying coupling (as will the power signal, but, for the purposes of the discussion of in-band data, it has now been filtered out at this point). Thus, the difference in magnitude of the amplified signals will vary by even more. At the upper end, substantially improved coupling may cause saturation of OPSD, at said upper end, if the system is tuned for small signal detection. Similarly, substantially degraded coupling may result in an undetectable signal if the system is tuned for high, good, and/or fair coupling. Moreover, a pre-amp signal with a positive offset may result in clipped (e.g., saturated) positive signals, post-amplification, unless gain is reduced; however, the reduced gain may in turn render negative signals undetectable. Additionally, a varying load at the receiver may affect the signal, necessitating the amplification of the data signal at the slope detector72. As such, instability in coupling is generally not well-tolerated by inductive charging systems, since it causes the filtered and amplified signal to vary too greatly. For example, a phone placed into a fitted dock will stay in a specific location relative to the dock, and any coupling therebetween will remain relatively constant. However, a phone placed on a desktop with an inductive charging station under the desktop may not maintain a fixed relative location, nor a fixed relative orientation and, thus, the range of coupling between the transmitter and the receiver of the phone may vary during the charging process. Further, consider a wireless power system configured for directly powering and/or charging a medical device, while the medical device resides within a human body. Due to natural displacement and/or internal movement of organic elements of the human body, the medical device may not maintain constant location, relative to the body and/or an associated charger positioned outside of the body, and, thus, the transmitter and receiver may couple at a wide range of high, good, fair, low, and/or insufficient coupling levels. Further still, consider a computer peripheral being charged by a charging mat on a user's desk. It may be desired to charge said peripheral, such as a mouse or other input device, during use of the device; such use of the peripheral will necessarily alter coupling during use, as it will be moved regularly, with respect to positioning of the transmitting charging mat. The effect caused by a difference in the coupling coefficient k can be illustrated by a few non-limiting examples. Consider a case wherein k=0.041, representing fairly strong coupling. In this case, the induced voltage delta (Vdelta) may be about 160 mV, with the corresponding amplified signal running between a peak of 3.15V and a nadir of 0.45V, for a swing of about 2.70V around a DC offset of 1.86V (i.e., 1.35V above and below the DC offset value). Now consider a case in the same system wherein a coupling value of 0.01 is exhibited, representing fairly weak coupling. This weakening could happen due to relative movement, intervening materials, or other circumstance. Now Vdeltamay be about 15 mV, with the corresponding amplified signal running between a peak of 1.94V and a nadir of 1.77V, for a swing of about 140 mV around a DC offset of 1.86V (i.e., about 70 mV above and below the DC offset value). As can be seen from this example, while the strongly coupled case yields robust signals, the weakly coupled case yields very small signals atop a fairly large offset. While perhaps generally detectable, these signal level present a significant risk of data errors and consequently lowered throughput. Moreover, while there is room for increased amplification, the level of amplification, especially given the DC offset, is constrained by the saturation level of the available economical operational amplifier circuits, which, in some examples may be about 4.0V. However, in an embodiment, automatic gain control in amplification is combined with a voltage offset in slope detection to allow the system to adapt to varying degrees of coupling. This is especially helpful in situations where the physical locations of the coupled devices are not tightly constrained during coupling. Continuing with the example ofFIG.7, in the illustrated circuit72, the bias voltage V′Biasfor slope detection is provided by a voltage divider77(including linked resistors RB1, RB2, RB3), which provides a voltage between Vinand ground based on a control voltage VHB. Given the control voltage VHB, the bias voltage V′Biasis set by adjusting a resistance in the voltage divider. In this connection, one of the resistors, e.g., RB3, may be a variable resistor, such as a digitally adjustable potentiometer, with the specific resistance being generated via an adaptive bias and gain protocol to be described below, e.g., Rbias. Similarly, in the illustrated circuit72, the output voltage VSDprovided to the next stage, comparator74, is first amplified at a level set by a voltage divider80(including linked resistors RA1, RA2, RA3), based on the control voltage VHAto generate V′SD(slope detection signal). The amplification of VSDto generate V′SD(amplified slope detection signal) is similarly set via a variable potentiometer in the voltage divider, e.g., RA1, being set to a specific value, e.g., Rgaingenerated via an adaptive bias and gain protocol to be described later below. With respect to the aforementioned, non-limiting example, with automatic gain and bias in slope detection, the circuit is configured to accommodate a Vamp slope deltaof between 400 mv and 2.2V, and a Vamp DCoffset of between 1.8V and 2.2V. In order to determine appropriate offsets and gains, the system may employ a beaconing sequence state. The beaconing sequence ensures that the transmitter is generally able to detect the receiver at all possible allowed coupling positions and orientations. Referring still toFIGS.7, the slope detector72includes a high pass filter71and an optional stabilizing circuit73. The high pass filter71is configured to monitor for higher frequency components of the AC wireless signals and may include, at least, a filter capacitor (CHF) and a filter resistor (RHF). The values for CHFand RHFare selected and/or tuned for a desired cutoff frequency for the high pass filter71. In some examples, the cutoff frequency for the high pass filter71may be selected as a value greater than or equal to about 1-2 kHz, to ensure adequately fast slope detection by the slope detector72, when the operating frequency of the system10is on the order of MHz (e.g., an operating frequency of about 6.78 MHz). In some examples, the high pass filter71is configured such that harmonic components of the detected slope are unfiltered. In view of the current sensor57ofFIG.5, the high pass filter71and the low pass filter55, in combination, may function as a bandpass filter for the demodulation circuit70. OPSDis any operational amplifier having an adequate bandwidth for proper signal response, for outputting the slope of VTx, but low enough to attenuate components of the signal that are based on the operating frequency and/or harmonics of the operating frequency. Additionally or alternatively, OPSDmay be selected to have a small input voltage range for VTx, such that OPSDmay avoid unnecessary error or clipping during large changes in voltage at VTx. Further, an input bias voltage (VBias) for OPSDmay be selected based on values that ensure OPSDwill not saturate under boundary conditions (e.g., steepest slopes, largest changes in VTx). It is to be noted, and is illustrated in Plot B ofFIG.8, that when no slope is detected, the output of the slope detector72will be VBias. As the passive components of the slope detector72will set the terminals and zeroes for a transfer function of the slope detector72, such passive components must be selected to ensure stability. To that end, if the desired and/or available components selected for CHFand RHFdo not adequately set the terminals and zeros for the transfer function, additional, optional stability capacitor(s) CSTmay be placed in parallel with RHFand stability resistor RSTmay be placed in the input path to OPSD. Output of the slope detector72(Plot B representing VSD) may approximate the following equation: VSD=-RHFCHFdVdt+VBias Thus, VSDwill approximate to VBias, when no change in voltage (slope) is detected, and Output VSDof the slope detector72is represented in Plot B. As can be seen, the value of VSDapproximates VBiaswhen no change in voltage (slope) is detected, whereas VSDwill output the change in voltage (dV/dt), as scaled by the high pass filter71, when VTxrises and falls between the high voltage and the low voltage of the ASK modulation. The output of the slope detector72, as illustrated in Plot B, may be a pulse, showing slope of VTxrise and fall. VSDis output to the comparator circuit(s)74, which is configured to receive VSD, compare VSDto a rising rate of change for the voltage (VSUp) and a falling rate of change for the voltage (VSLo). If VSDexceeds or meets VSUp, then the comparator circuit will determine that the change in VTxmeets the rise threshold and indicates a rising edge in the ASK modulation. If VSDgoes below or meets VSLow, then the comparator circuit will determine that the change in VTxmeets the fall threshold and indicates a falling edge of the ASK modulation. It is to be noted that VSUpand VSLomay be selected to ensure a symmetrical triggering. FIG.8is an exemplary timing diagram illustrating signal shape or waveform at various stages or sub-circuits of the demodulation circuit70. The input signal to the demodulation circuit70is illustrated inFIG.8as Plot A, showing rising and falling edges from a “high” voltage (VHigh) perturbation on the transmission antenna21to a “low” voltage (VLow) perturbation on the transmission antenna21. The voltage signal of Plot A may be derived from, for example, a current (ITx) sensed at the transmission antenna21by one or more sensors of the sensing system50. Such rises and falls from VHighto VLowmay be caused by load modulation, performed at the wireless receiver system(s)30, to modulate the wireless power signals to include the wireless data signals via ASK modulation. As illustrated, the voltage of Plot A does not cleanly rise and fall when the ASK modulation is performed; rather, a slope or slopes, indicating rate(s) of change, occur during the transitions from VHighto VLowand vice versa. As illustrated inFIG.7, the slope detector72includes a high pass filter71, an operation amplifier (OpAmp) OPSD, and an optional stabilizing circuit73. The high pass filter71is configured to monitor for higher frequency components of the AC wireless signals and may include, at least, a filter capacitor (CHF) and a filter resistor (RHF). The values for CHFand RHFare selected and/or tuned for a desired cutoff frequency for the high pass filter71. In some examples, the cutoff frequency for the high pass filter71may be selected as a value greater than or equal to about 1-2 kHz, to ensure adequately fast slope detection by the slope detector72, when the operating frequency of the system10is on the order of MHz (e.g., an operating frequency of about 6.78 MHz). In some examples, the high pass filter71is configured such that harmonic components of the detected slope are unfiltered. In view of the current sensor57ofFIG.5, the high pass filter71and the low pass filter55, in combination, may function as a bandpass filter for the demodulation circuit70. OPSDis any operational amplifier having an adequate bandwidth for proper signal response, for outputting the slope of VTx, but low enough to attenuate components of the signal that are based on the operating frequency and/or harmonics of the operating frequency. Additionally or alternatively, OPSDmay be selected to have a small input voltage range for VTx, such that OPSDmay avoid unnecessary error or clipping during large changes in voltage at VTx. Further, an input bias voltage (VBias) for OPSDmay be selected based on values that ensure OPSDwill not saturate under boundary conditions (e.g., steepest slopes, largest changes in VTx). It is to be noted, and is illustrated in Plot B ofFIG.8, that when no slope is detected, the output of the slope detector72will be VBias. As the passive components of the slope detector72will set the terminals and zeroes for a transfer function of the slope detector72, such passive components must be selected to ensure stability. To that end, if the desired and/or available components selected for CHFand RHFdo not adequately set the terminals and zeros for the transfer function, additional, optional stability capacitor(s) CSTmay be placed in parallel with RHFand stability resistor RSTmay be placed in the input path to OPSD. Output of the slope detector72(Plot B representing VSD) may approximate the following equation: VSD=-RHFCHFdVdt+VBias Thus, VSDwill approximate to VBias, when no change in voltage (slope) is detected, and output VSDof the slope detector72is represented in Plot B. As can be seen, the value of VSDapproximates VBiaswhen no change in voltage (slope) is detected, whereas VSDwill output the change in voltage (dV/dt), as scaled by the high pass filter71, when VTxrises and falls between the high voltage and the low voltage of the ASK modulation. The output of the slope detector72, as illustrated in Plot B, may be a pulse, showing slope of VTxrise and fall. VSDis output to the comparator circuit(s)74, which is configured to receive VSD, compare VSDto a rising rate of change for the voltage (VSUp) and a falling rate of change for the voltage (VSLo). If VSDexceeds or meets VSUp, then the comparator circuit will determine that the change in VTxmeets the rise threshold and indicates a rising edge in the ASK modulation. If VSDgoes below or meets VSLow, then the comparator circuit will determine that the change in VTxmeets the fall threshold and indicates a falling edge of the ASK modulation. It is to be noted that VSUpand VSLomay be selected to ensure a symmetrical triggering. In some examples, such as the comparator circuit74illustrated inFIG.6, the comparator circuit74may comprise a window comparator circuit. In such examples, the VSUpand VSLomay be set as a fraction of the power supply determined by resistor values of the comparator circuit74. In some such examples, resistor values in the comparator circuit may be configured such that VSup=Vin[RU2RU1+RU2]VSLo=Vin[RL2RL1+RL2] where Vin is a power supply determined by the comparator circuit74. When VSDexceeds the set limits for VSupor VSLo, the comparator circuit74triggers and pulls the output (VCout) low. Further, while the output of the comparator circuit74could be output to the transmission controller28and utilized to decode the wireless data signals by signaling the rising and falling edges of the ASK modulation, in some examples, the SR latch76may be included to add noise reduction and/or a filtering mechanism for the slope detector72. The SR latch76may be configured to latch the signal (Plot C) in a steady state to be read by the transmitter controller28, until a reset is performed. In some examples, the SR latch76may perform functions of latching the comparator signal and serve as an inverter to create an active high alert out signal. Accordingly, the SR latch76may be any SR latch known in the art configured to sequentially excite when the system detects a slope or other modulation excitation. As illustrated, the SR latch76may include NOR gates, wherein such NOR gates may be configured to have an adequate propagation delay for the signal. For example, the SR latch76may include two NOR gates (NORUp, NORLo), each NOR gate operatively associated with the upper voltage output78of the comparator74and the lower voltage output79of the comparator74. In some examples, such as those illustrated in Plot C, a reset of the SR latch76is triggered when the comparator circuit74outputs detection of VSUp(solid plot on Plot C) and a set of the SR latch76is triggered when the comparator circuit74outputs VSLo(dashed plot on Plot C). Thus, the reset of the SR latch76indicates a falling edge of the ASK modulation and the set of the SR latch76indicates a rising edge of the ASK modulation. Accordingly, as illustrated in Plot D, the rising and falling edges, indicated by the demodulation circuit70, are input to the transmission controller28as alerts, which are decoded to determine the received wireless data signal transmitted, via the ASK modulation, from the wireless receiver system(s)30. The incoming signal VTX exemplified in the plots ofFIG.8does not lead to excess bias or saturation because the values of VBIASand VGare at appropriate levels, but the coupling environment may change (e.g., from strong to weak coupling), such that the existing VBIASand VGare no longer appropriate and would no longer allow accurate signal detection. However, automatic gain and bias routines are applied as described herein to continually evaluate the system behavior and set VBIASand VGsuch that accurate signal detection is provided throughout the range of allowable coupling strengths. Referring now toFIG.9, and with continued reference toFIGS.1-4, a block diagram illustrating an embodiment of the power conditioning system40is illustrated. At the power conditioning system40, electrical power is received, generally, as a DC power source, via the input power source12itself or an intervening power converter, converting an AC source to a DC source (not shown). A voltage regulator46receives the electrical power from the input power source12and is configured to provide electrical power for transmission by the antenna21and provide electrical power for powering components of the wireless transmission system21. Accordingly, the voltage regulator46is configured to convert the received electrical power into at least two electrical power signals, each at a proper voltage for operation of the respective downstream components: a first electrical power signal to electrically power any components of the wireless transmission system20and a second portion conditioned and modified for wireless transmission to the wireless receiver system30. As illustrated inFIG.3, such a first portion is transmitted to, at least, the sensing system50, the transmission controller28, and the communications system29; however, the first portion is not limited to transmission to just these components and can be transmitted to any electrical components of the wireless transmission system20. The second portion of the electrical power is provided to an amplifier42of the power conditioning system40, which is configured to condition the electrical power for wireless transmission by the antenna21. The amplifier may function as an inverter, which receives an input DC power signal from the voltage regulator46and generates an AC as output, based, at least in part, on PWM input from the transmission control system26. The amplifier42may be or include, for example, a power stage invertor, such as a single field effect transistor (FET), a dual field effect transistor power stage invertor or a quadruple field effect transistor power stage invertor. The use of the amplifier42within the power conditioning system40and, in turn, the wireless transmission system20enables wireless transmission of electrical signals having much greater amplitudes than if transmitted without such an amplifier. For example, the addition of the amplifier42may enable the wireless transmission system20to transmit electrical energy as an electrical power signal having electrical power from about 10 mW to about 500 W. In some examples, the amplifier42may be or may include one or more class-E power amplifiers. Class-E power amplifiers are efficiently tuned switching power amplifiers designed for use at high frequencies (e.g., frequencies from about 1 MHz to about 1 GHz). Generally, a single-ended class-E amplifier employs a single-terminal switching element and a tuned reactive network between the switch and an output load (e.g., the antenna21). Class E amplifiers may achieve high efficiency at high frequencies by only operating the switching element at points of zero current (e.g., on-to-off switching) or zero voltage (off to on switching). Such switching characteristics may minimize power lost in the switch, even when the switching time of the device is long compared to the frequency of operation. However, the amplifier42is certainly not limited to being a class-E power amplifier and may be or may include one or more of a class D amplifier, a class EF amplifier, an H invertor amplifier, and/or a push-pull invertor, among other amplifiers that could be included as part of the amplifier42. Turning now toFIG.10and with continued reference to, at least,FIGS.1and2, the wireless receiver system30is illustrated in further detail. The wireless receiver system30is configured to receive, at least, electrical energy, electrical power, electromagnetic energy, and/or electrically transmittable data via near field magnetic coupling from the wireless transmission system20, via the transmission antenna21. As illustrated inFIG.9, the wireless receiver system30includes, at least, the receiver antenna31, a receiver tuning and filtering system34, a power conditioning system32, a receiver control system36, and a voltage isolation circuit70. The receiver tuning and filtering system34may be configured to substantially match the electrical impedance of the wireless transmission system20. In some examples, the receiver tuning and filtering system34may be configured to dynamically adjust and substantially match the electrical impedance of the receiver antenna31to a characteristic impedance of the power generator or the load at a driving frequency of the transmission antenna20. As illustrated, the power conditioning system32includes a rectifier33and a voltage regulator35. In some examples, the rectifier33is in electrical connection with the receiver tuning and filtering system34. The rectifier33is configured to modify the received electrical energy from an alternating current electrical energy signal to a direct current electrical energy signal. In some examples, the rectifier33is comprised of at least one diode. Some non-limiting example configurations for the rectifier33include, but are not limited to including, a full wave rectifier, including a center tapped full wave rectifier and a full wave rectifier with filter, a half wave rectifier, including a half wave rectifier with filter, a bridge rectifier, including a bridge rectifier with filter, a split supply rectifier, a single phase rectifier, a three phase rectifier, a voltage doubler, a synchronous voltage rectifier, a controlled rectifier, an uncontrolled rectifier, and a half controlled rectifier. As electronic devices may be sensitive to voltage, additional protection of the electronic device may be provided by clipper circuits or devices. In this respect, the rectifier33may further include a clipper circuit or a clipper device, which is a circuit or device that removes either the positive half (top half), the negative half (bottom half), or both the positive and the negative halves of an input AC signal. In other words, a clipper is a circuit or device that limits the positive amplitude, the negative amplitude, or both the positive and the negative amplitudes of the input AC signal. Some non-limiting examples of a voltage regulator35include, but are not limited to, including a series linear voltage regulator, a buck convertor, a low dropout (LDO) regulator, a shunt linear voltage regulator, a step up switching voltage regulator, a step down switching voltage regulator, an inverter voltage regulator, a Zener controlled transistor series voltage regulator, a charge pump regulator, and an emitter follower voltage regulator. The voltage regulator35may further include a voltage multiplier, which is as an electronic circuit or device that delivers an output voltage having an amplitude (peak value) that is two, three, or more times greater than the amplitude (peak value) of the input voltage. The voltage regulator35is in electrical connection with the rectifier33and configured to adjust the amplitude of the electrical voltage of the wirelessly received electrical energy signal, after conversion to AC by the rectifier33. In some examples, the voltage regulator35may an LDO linear voltage regulator; however, other voltage regulation circuits and/or systems are contemplated. As illustrated, the direct current electrical energy signal output by the voltage regulator35is received at the load16of the electronic device14. In some examples, a portion of the direct current electrical power signal may be utilized to power the receiver control system36and any components thereof; however, it is certainly possible that the receiver control system36, and any components thereof, may be powered and/or receive signals from the load16(e.g., when the load16is a battery and/or other power source) and/or other components of the electronic device14. The receiver control system36may include, but is not limited to including, a receiver controller38, a communications system39and a memory37. The receiver controller38may be any electronic controller or computing system that includes, at least, a processor which performs operations, executes control algorithms, stores data, retrieves data, gathers data, controls and/or provides communication with other components and/or subsystems associated with the wireless receiver system30. The receiver controller38may be a single controller or may include more than one controller disposed to control various functions and/or features of the wireless receiver system30. Functionality of the receiver controller38may be implemented in hardware and/or software and may rely on one or more data maps relating to the operation of the wireless receiver system30. To that end, the receiver controller38may be operatively associated with the memory37. The memory may include one or both of internal memory, external memory, and/or remote memory (e.g., a database and/or server operatively connected to the receiver controller38via a network, such as, but not limited to, the Internet). The internal memory and/or external memory may include, but are not limited to including, one or more of a read only memory (ROM), including programmable read-only memory (PROM), erasable programmable read-only memory (EPROM or sometimes but rarely labelled EROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDR SDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data rate synchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5), a flash memory, a portable memory, and the like. Such memory media are examples of nontransitory computer readable memory media. Further, while particular elements of the receiver control system36are illustrated as subcomponents and/or circuits (e.g., the memory37, the communications system39, among other contemplated elements) of the receiver control system36, such components may be external of the receiver controller38. In some examples, the receiver controller38may be and/or include one or more integrated circuits configured to include functional elements of one or both of the receiver controller38and the wireless receiver system30, generally. As used herein, the term “integrated circuits” generally refers to a circuit in which all or some of the circuit elements are inseparably associated and electrically interconnected so that it is considered to be indivisible for the purposes of construction and commerce. Such integrated circuits may include, but are not limited to including, thin-film transistors, thick-film technologies, and/or hybrid integrated circuits. In some examples, the wireless power transmission system20may be configured to transmit power over a large charge area, within which the wireless power receiver system30may receive said power. A “charge area” may be an area associated with and proximate to a wireless power transmission system20and/or a transmission antenna21and within said area a wireless power receiver30is capable of coupling with the transmission system20or transmission antenna21at a plurality of points within the charge area. To that end, it is advantageous, both for functionality and user experience, that the plurality of points for coupling within a charge area include as many points as possible and with as much of a consistent ability to couple with a receiver system30, within the given charge area. In some examples, a “large charge area” may be a charge area wherein the X-Y axis spatial freedom is within an area bounded by a width (across the area, or in an “X” axis direction) of about 150 mm to about 500 mm and bounded by a length (height of the area, or in an “Y” axis direction) of about 50 mm to about 350 mm. While the following antennas21disclosed are applicable to “large area” or “large charge area” wireless power transmission antennas, the teachings disclosed herein may also be applicable to transmission or receiver antennas having smaller or larger charge areas, then those discussed above. It is advantageous for large area power transmitters to be designed with maximum uniformity of power transmission in mind. Thus, it may be advantageous to design such transmission antennas21with uniformity ratio in mind. “Uniformity ratio,” as defined herein, refers to the ratio of a maximum coupling, between a wireless transmission system20and wireless receiver system30, to a minimum coupling between said systems20,30, wherein said coupling values are determined by measuring or determining a coupling between the systems20,30at a plurality of points at which the wireless receiver system30and/or antenna31are placed within the charge area of the transmission antenna21. In other words, the uniformity ratio is a ratio between the coupling when the receiver antenna31is positioned at a point, relative to the transmission antenna21area, that provides the highest coupling (CMAX) versus the coupling when the receiver antenna31is positioned at a point, relative to the charge area of the transmission antenna21, that provides for the lowest coupling (CMIN). Thus, uniformity ratio for a charge area (UAREA) may be defined as: UAREA=CMAX/CMIN. To that end, a perfectly uniform charge area would have a uniformity ratio of 1, as CMAX=CMINfor a fully uniform charge area. Further, while uniformity ratio can be enhanced by using more turns, coils, and/or other resonant bodies within an antenna, increasing such use of more conductive metals to maximize uniformity ratio may give rise to cost concerns, bill of material concerns, environmental concerns, and/or sustainability concerns, among other known drawbacks from inclusion of more conductive materials. To that end, the following transmission antennas21may be designed by balancing uniformity ratio considerations with cost, environmental, and/or sustainability considerations. In other words, the following transmission antennas21may be configured to achieve an increased (e.g., maximized) uniformity ratio, while reducing (e.g., minimizing) the use or the length of conductive wires and/or traces. Further, while the following antennas21may be embodied by PCB or flex PCB antennas, in some examples, the following antennas21may be wire wound antennas that eschew the use of any standard PCB substrate. By reducing or perhaps even eliminating the use of PCB substrate, cost and or environmental concerns associated with PCB substrates may be reduced and/or eliminated. Turning now toFIG.11A, another example of a wireless power transmission antenna921A, for transmitting wireless power to a receiver system30over a large charge area, is illustrated. The antenna921A may be utilized as the transmission antenna21in any of the aforementioned wireless transmission systems20. The transmission antenna(s)925include multiple transmission coils925, wherein at least one transmission coil is a source coil925A and at least one transmission coil925is an internal repeater coil925B. The source coil925A is comprised of a first continuous conductive wire924A and includes a first outer turn953A and a first inner turn951A. While illustrated with only one first outer turn953A and one first inner turn951A, it is certainly contemplated that the antenna921A may include multiple outer turns953A and inner turns951A. The source coil925A is configured to connect to one or more electronic components120of the wireless transmission system20. The first conductive wire begins at a first source terminal926, which leads to or is part of the beginning of the first outer turn951A, and ends at a second source terminal, which is associated or is part of the ending928of the first inner turn951A. The internal repeater coil925B may take a similar shape to that of the source coil925A, but is not directly, electrically connected to the one or more electrical components120of the wireless transmission system20. Rather, the internal repeater coil925B is a repeater configured to have a repeater current induced in it by the source coil925A. As defined herein, a “repeater” is an antenna or coil that is configured to relay magnetic fields emanating between a transmission antenna (e.g., the source coil925A) and one or both of a receiver antenna31and one or more other antennas or coils, when such subsequent coils or antennas are configured as repeaters. Thus, the internal repeater coil925B may be configured to relay electrical energy and/or data via NMFC from the initial transmitting antenna (e.g., the source coil925A) to a receiver antenna31or to another repeating antenna or coil. In one or more embodiments, such repeating coils or antennas (e.g., the repeater coil925B) comprise an inductor coil capable of resonating at a frequency that is about the same as the resonating frequency of the initial transmitting antenna (e.g. the source coil925A) and the receiver antenna31. Further, it is certainly possible that an initial transmitting antenna may transfer electrical signals and/or couple with one or more other antennas (repeaters or receivers) and transfer, at least in part, components of the output signals or magnetic fields of the transmitting antenna. Such transmission may include secondary and/or stray coupling or signal transfer to multiple antennas of the system(s)10,20,30. As mentioned, the coil925B is referred to as an “internal repeater” to either the transmission antenna921,21and/or the wireless transmission system20, as it is contained as part of a common system20or antenna921,21. An “internal repeater” as defined herein is a repeater coil or antenna that is utilized as part of a unitary antenna, rather than as a repeater outside the bounds of the overall system. For example, a user of the wireless power transmission system20would not know the difference between a system20with an internal repeater and one in which all coils are wired to the electrical components120, so long as both systems are housed in an opaque mechanical housing (e.g., a mechanical housing960). Internal repeaters may be beneficial for use in unitary wireless transmission antennas because they allow for longer wires for coils, without introducing electromagnetic interference (EMI) that are associated with longer wires connected to a common wired signal source. Additionally or alternatively, use of internal repeaters may be beneficial in improving metal resiliency and/or uniformity ratio for the wireless transmission antenna(s)21. Configuration of the inner turns951and outer turns953, with respect to one another, of the coils925is designed for controlling a direction of current flow through each of the coils925. Current flow direction is illustrated by the dotted lines inFIG.11A. As illustrated, the current may enter the source coil925A, from the one or more electrical components120, at the first source terminal at the beginning of the first outer turn953A and then flow through the first outer turn in a first source coil direction. Said source coil direction may be, for example, a clockwise direction, as illustrated. Then, at the end of the first outer turn953A, where the first outer turn953A turns into the first inner turn951A, the current will change directions to a second source direction, which is substantially opposite of the first source direction. In some examples and as illustrated, the second source direction may be a counter-clockwise direction, which is substantially opposite of the clockwise direction of the current flow through the first outer turn953A. The internal repeater coil925B is configured such that a current is induced in it by the source coil925A and direction(s) of the current induced in the internal repeater coil925B is/are illustrated by the dotted lines inFIG.11A. The induced current of the internal repeater coil925B may have a first repeater direction, flowing through the second outer turn953B of the internal repeater coil925B. The first repeater direction may be, for example and as illustrated, a counter-clockwise direction. Then, at the end of the second outer turn953B, where the second outer turn953B turns into the second inner turn951B, the current will change directions to a second repeater direction, which is substantially opposite of the first repeater direction, In some examples and as illustrated, the second source direction may be a clockwise direction, which is substantially opposite of the counter-clockwise direction of the current flow through the second outer turn953B. As illustrated and described, the first repeater direction (counter-clockwise) may be substantially opposite of the first source direction (clockwise). Thus, as one views the antenna921both from left-to-right and from top-to-bottom, the current direction reverses from turn to turn. By reversing current directions from turn-to-turn both laterally (side to side) and from top-to-bottom, optimal field uniformity may be maintained. By reversing current directions amongst inner and outer turns951,953, both laterally and top-to-bottom, a receiver antenna31travelling across the charge area of the antenna921will more often be positioned more closer-to-perpendicular with the magnetic field emanating from the antenna921. Thus, as a receiver antenna31will best couple with the transmission antenna921at points of perpendicularity with the magnetic field, the charge area generated by the antenna921will have greater uniformity than if all of the turns951,953carried the current in a common direction. As illustrated, the source coil925A and the internal repeater coil925B may be configured to be housed in a common, unitary housing960. By utilizing the internal repeater coil925B, rather than one larger source coil, EMI benefits may be seen, as a shorter wire connected to the source may reduce EMI issues. Additionally, by utilizing the internal repeater coil925B, the aforementioned reversals of current direction may be better achieved, which enhances uniformity and metal resilience in the transmission antenna921. In some examples, while the internal repeater coil925B may be a “passive” inductor (e.g., not connected directly, by wired means, to a power source), it still may be connected to one or more components of a repeater tuning system923A. The repeater tuning system923A may include one or more components, such as a tuning capacitor, configured to tune the internal repeater coil925B to operate at an operating frequency similar to that of the source coil925A and/or any receiver antenna(s)31, to which the repeater coil925B intends to transfer wireless power. The repeater tuning system923A may be positioned, in a signal path of the internal repeater coil925B, connecting the beginning of the second outer turn953B and the ending of the second inner turn951B, as illustrated. One or more of the source coil925A, the internal repeater coil925B, and combinations thereof may form or combine to form a substantially rectangular shape, as illustrated. In some examples, such substantially rectangular shape(s) of one or more of the source coil925A, the internal repeater coil925B, and combinations thereof may additionally have rounded edges, as illustrated inFIG.11A. In some such examples, shape of the coils925A,925B may both be oriented in a “column” type rectangular formation, wherein, when viewed in a top view perspective, the coils925A,B are arranged from top to bottom in a singular row. Alternatively, as illustrated inFIG.11Band including like and/or similar elements to those ofFIG.11Aas indicated by like reference numbers, the coils925C, D ofFIG.11Bmay be arranged in a “row” type formation, where the coils925C, D are arranged next to one another in a “side-to-side” lateral fashion. Any of the subsequently discussed antennas921having a source-internal repeater configuration may have either a “row formation” or a “column formation.” FIG.11Cis another example of a transmission antenna921C that has a source-internal repeater configuration, similar to those ofFIGS.11A,11Band, thus, including like or similar elements to those ofFIGS.11A,11B, which share common reference numbers and descriptions herein. The antenna921C includes a repeater tuning system923B, which is functionally equivalent to the repeater tuning system923A ofFIGS.11A,11B, but is disposed within the bounds of the inner repeater coil925B. For example, the repeater tuning system923B may be disposed on a substrate962that is independent of the one or more electrical components120of the wireless transmission system20. In such examples, the substrate962and/or the tuning system923B absent a substrate may be positioned radially inward of the second outer turn953B, as illustrated inFIG.11C. Alternatively, as illustrated in an antenna921D ofFIG.11D, which includes like or similar elements to those ofFIGS.11A-Cwhich share common reference numbers and descriptions herein, the tuning system923B may be similarly connected to the outer and inner turns953B,951B, but the tuning system923B and/or the associated substrate962may be positioned radially inward of the second inner turn951B. In some examples wherein the repeater tuning system923B is disposed radially inward of the second outer turn953B, one or more capacitors of the repeater tuning system923B may be interdigitated capacitors. An interdigitated capacitor is an element for producing capacitor-like characteristics by using microstrip lines, which can be disposed as conductive materials on a substrate or other surface. To that end, capacitors of the repeater tuning system923B may be interdigitated capacitors disposed on the substrate962. Additionally or alternatively, interdigitated capacitors of the repeater tuning system923B may be disposed on another surface, such as a dielectric surface of the housing960. By disposing the repeater tuning system within or in close proximity to the internal repeater coil925B, long wires extending to a circuit board, such as one associated with the one or more components120, may be omitted. By omitting such long wires, complexity of manufacture may be reduced. Additionally or alternatively, by shortening the connection to the tuning system923B by keeping it close by the internal repeater coil925B, EMI concerns related to long connecting wires may be mitigated. Turning now toFIG.11E, another antenna921E is illustrated, having a source coil925E and repeater coil925F configuration and, thus, including like or similar elements to those ofFIGS.11A-D, which share common reference numbers and descriptions herein. The antenna921E includes a first plurality of outer turns953E, a first plurality of inner turns951E, a second plurality of outer turns953F, and a second plurality of inner turns951F. The source coil925E is connected to the one or more electrical components via a first source terminal proximate to a beginning of the first plurality of outer turns953E and a second source terminal proximate to an ending of the first plurality of inner turns951E. The internal repeater coil925F may be connected to a repeater tuning system923via a first repeater terminal proximate to a beginning of the second plurality of outer turns953F and a second repeater terminal proximate to an ending of the second plurality of inner turns951F. Inter-turn capacitors may957be connected in between the first plurality of outer turns953E and the first plurality of inner turns951E and in between the second plurality of outer turns953F and the second plurality of inner turns951F In some examples, the first and second plurality of outer turns953E,953F may include about 2 turns and the first and second plurality of inner turns951E,951F may include about 3 turns. FIG.12illustrates an example, non-limiting embodiment of the receiver antenna31that may be used with any of the systems, methods, and/or apparatus disclosed herein. In the illustrated embodiment, the antenna31, is a flat spiral coil configuration. Non-limiting examples can be found in U.S. Pat. Nos. 9,941,743, 9,960,628, 9,941,743 all to Peralta et al.; 9,948,129, 10,063,100 to Singh et al.; U.S. Pat. No. 9,941,590 to Luzinski; U.S. Pat. No. 9,960,629 to Rajagopalan et al.; and U.S. Patent App. Nos. 2017/0040107, 2017/0040105, 2017/0040688 to Peralta et al.; all of which are assigned to the assignee of the present application and incorporated fully herein by reference. In addition, the antenna31may be constructed having a multi-layer-multi-turn (MLMT) construction in which at least one insulator is positioned between a plurality of conductors. Non-limiting examples of antennas having an MLMT construction that may be incorporated within the wireless transmission system(s)20and/or the wireless receiver system(s)30may be found in U.S. Pat. Nos. 8,610,530, 8,653,927, 8,680,960, 8,692,641, 8,692,642, 8,698,590, 8,698,591, 8,707,546, 8,710,948, 8,803,649, 8,823,481, 8,823,482, 8,855,786, 8,898,885, 9,208,942, 9,232,893, and 9,300,046 to Singh et al., all of which are assigned to the assignee of the present application are incorporated fully herein. These are merely exemplary antenna examples; however, it is contemplated that the antennas31may be any antenna capable of the aforementioned higher power, high frequency wireless power transfer. The automatic gain and bias control described herein may significantly reduce the BOM for the demodulation circuit, and the wireless transmission system as a whole, by allowing usage of cheaper, less computationally capable processor(s) for or with the transmission controller. The throughput and accuracy of an edge-detection coding scheme depends in large part upon the system's ability to quickly and accurately detect signal slope changes. These constraints may be better met in environments wherein the distance between, and orientations of, the sender and receiver change dynamically, or the magnitude of the received power signal and embedded data signal may change dynamically, via the disclosed automatic gain and bias control. This may allow reading of faint signals via appropriate gain, for example, while also avoiding saturation with respect to larger signals. The systems, methods, and apparatus disclosed herein are designed to operate in an efficient, stable and reliable manner to satisfy a variety of operating and environmental conditions. The systems, methods, and/or apparatus disclosed herein are designed to operate in a wide range of thermal and mechanical stress environments so that data and/or electrical energy is transmitted efficiently and with minimal loss. In addition, the system10may be designed with a small form factor using a fabrication technology that allows for scalability, and at a cost that is amenable to developers and adopters. In addition, the systems, methods, and apparatus disclosed herein may be designed to operate over a wide range of frequencies to meet the requirements of a wide range of applications. While illustrated as individual blocks and/or components of the wireless transmission system20, one or more of the components of the wireless transmission system20may combined and/or integrated with one another as an integrated circuit (IC), a system-on-a-chip (SoC), among other contemplated integrated components. To that end, one or more of the transmission control system26, the power conditioning system40, the sensing system50, the transmitter coil21, and/or any combinations thereof may be combined as integrated components for one or more of the wireless transmission system20, the wireless power transfer system10, and components thereof. Further, any operations, components, and/or functions discussed with respect to the wireless transmission system20and/or components thereof may be functionally embodied by hardware, software, and/or firmware of the wireless transmission system20. Similarly, while illustrated as individual blocks and/or components of the wireless receiver system30, one or more of the components of the wireless receiver system30may combined and/or integrated with one another as an IC, a SoC, among other contemplated integrated components. To that end, one or more of the components of the wireless receiver system30and/or any combinations thereof may be combined as integrated components for one or more of the wireless receiver system30, the wireless power transfer system10, and components thereof. Further, any operations, components, and/or functions discussed with respect to the wireless receiver system30and/or components thereof may be functionally embodied by hardware, software, and/or firmware of the wireless receiver system30. In an embodiment, a ferrite shield may be incorporated within the antenna structure to improve antenna performance. Selection of the ferrite shield material may be dependent on the operating frequency as the complex magnetic permeability (μ=μ′−j*μ″) is frequency dependent. The material may be a polymer, a sintered flexible ferrite sheet, a rigid shield, or a hybrid shield, wherein the hybrid shield comprises a rigid portion and a flexible portion. Additionally, the magnetic shield may be composed of varying material compositions. Examples of materials may include, but are not limited to, zinc comprising ferrite materials such as manganese-zinc, nickel-zinc, copper-zinc, magnesium-zinc, and combinations thereof. As used herein, the phrase “at least one of” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” does not require selection of at least one of each item listed; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. The predicate words “configured to”, “operable to”, and “programmed to” do not imply any particular tangible or intangible modification of a subject, but, rather, are intended to be used interchangeably. In one or more embodiments, a processor configured to monitor and control an operation or a component may also mean the processor being programmed to monitor and control the operation or the processor being operable to monitor and control the operation. Likewise, a processor configured to execute code can be construed as a processor programmed to execute code or operable to execute code. A phrase such as “an aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples of the disclosure. A phrase such as an “aspect” may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples of the disclosure. A phrase such an “embodiment” may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples of the disclosure. A phrase such as a “configuration” may refer to one or more configurations and vice versa. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” or as an “example” is not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the subject disclosure. While this specification contains many specifics, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of particular implementations of the subject matter. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub combination or variation of a sub combination. | 92,482 |
11862992 | DETAILED DESCRIPTION According to an embodiment, a power transmission device performs power transmission without contact with a power reception device. The power transmission device includes a power transmission coil, a power transmission circuit, a current detection circuit, and a control circuit. The power transmission circuit generates transmission power and supplies the generated transmission power to the power transmission coil. The current detection circuit measures a current value input to the power transmission circuit. The control circuit measures, using the current detection circuit, a standby current in a standby state in which the power transmission to the power reception device is not performed, to obtain the measured current value as a reference value. The control circuit sets, as a foreign matter detection threshold, a value obtained by adding a constant value to the reference value or a value obtained by adding a constant ratio to the reference value. Further, the control circuit determines, in the standby state, when the current value detected by the current detection circuit is equal to or larger than the foreign matter detection threshold, that there is a foreign matter on the power transmission coil. Hereinafter, a power supply system1and a power transmission device35according to a first embodiment will be described with reference toFIGS.1to8. In the drawings, the same reference symbols represent the same or similar portions.FIG.1is a perspective view showing a configuration of the power supply system1according to the first embodiment, andFIG.2is a perspective view of a cart2of the power supply system1.FIG.3is a block diagram showing a configuration of a control system of the power supply system1.FIG.4is a perspective view showing configurations of a power reception device23and the power transmission device35.FIG.5is a flowchart showing an example of power transmission processing performed by the power transmission device35, andFIG.6is a flowchart showing processing of setting a foreign matter detection threshold T in the power transmission processing performed by the power transmission device35.FIG.7is a diagram for describing an example of a change in transmission current by the power transmission device35, andFIG.8is diagram for describing an example of a change in transmission current by each power transmission device35. As shown inFIGS.1and3, the power supply system1includes the power reception device23and the power transmission device35. The power reception device23is provided to, for example, the cart2. For example, a plurality of power transmission devices35are provided to a cart base3that houses a plurality of carts2. In the following description of the embodiment, an example in which the power reception device23and the power transmission device35are respectively applied to the cart2and the cart base3in the power supply system1will be described. As shown inFIG.1, the power supply system1includes the cart2including the power reception device23, and the cart base3in which the carts2are installed and which includes the plurality of power transmission devices35. In the power supply system1, in the cart base3in which the plurality of power transmission devices35are disposed side by side in one direction, the plurality of carts2each including the power reception device23are housed side by side in one direction, and the plurality of power transmission devices35and the plurality of power reception devices23are disposed to face each other at predetermined intervals. The cart2shown inFIG.2is a moving object and is a shopping cart, for example. The cart2includes a frame11, a basket portion12, front and rear casters151and152, an electronic device21, a battery box223in which a battery22(object to be supplied with power) is provided, and the power reception device23. The frame11is formed by assembling a plurality of frame members extending in different directions. The frame11supports the basket portion12, the plurality of casters151and152, various electronic devices21, and the power reception device23at predetermined positions. The frame11includes, for example, a pair of right and left vertical frame portions111, a lower frame portion112, a horizontal frame portion113, a handle portion114, and a mounting frame115. The vertical frame portions111, the lower frame portion112, and the horizontal frame portion113extend in directions intersecting with each other. The vertical frame portions111include a pair of main frames1111extending upward from the rear wheel casters152, a pair of sub-frames1112provided on the rear side of the main frames1111, and a pair of sub-frames1113provided on the front side of the main frames1111. The vertical frame portions111extend in the vertical direction behind the basket portion12, and the rear wheel casters152are disposed at the lower end portions of the vertical frame portions111. The lower frame portion112includes a plurality of frame members disposed along the floor surface. The lower frame portion112includes, for example, a pair of main frames1121, a support frame1123, a front coupling portion1124, and an mounting portion1125provided below the support frame1123. The main frames1121extend forward from the rear wheel casters152toward the front wheel casters151. The support frame1123is a frame member that extends downward from the horizontal frame portion113, bends forward at a predetermined height, extends forward, and bends upward at a front end portion. The support frame1123is formed of, for example, a U-shaped frame member bent and folded back on the front side. The support frame1123extends along a plane parallel to the floor surface on the inward side of the main frame1121. The support frame1123forms a place for a basket on the upper side thereof. The front coupling portion1124extends in the width direction at the front end portion of the lower end of the cart2, and couples the front ends of the pair of main frames1121. An upper end portion of the mounting portion1125is fixed to a predetermined position of the support frame1123. The mounting portion1125extends downward from the support frame1123, bends backward at a predetermined height, and extends backward. The mounting portion1125is a frame member on which the power reception device23is mounted. The mounting portion1125extends along a plane parallel to the floor surface on the inward side of the main frame1121, and forms a support surface that supports the power reception device23below the support frame1123. For example, the mounting portion1125is set to have a dimension, in which the power transmission device35provided on the cart base3and the power reception device23provided on the mounting portion1125are disposed to face each other with a predetermined interval therebetween when the cart2is installed in the cart base3. The horizontal frame portion113includes a plurality of link frames1131,1132, and1133that are bridged between the right and left vertical frame portions111and extend in the width direction. The handle portion114is disposed at the upper rear end portion of the cart2. The handle portion114is disposed to be continuous with the upper end portions of the vertical frame portions111. As an example, the handle portion114extends in the width direction. The mounting frame115is connected to the vertical frame portion111. For example, the mounting frame115extends upward at one of the vertical frame portions111and supports the various electronic devices21. In the frame11, the basket portion12is supported by the vertical frame portions111. The front wheel casters151and the rear wheel casters152are respectively provided at the front end portions and the rear end portions of the lower frame portion112disposed below the basket portion12. Further, in the frame11, the power reception device23is provided on the mounting portion1125, of the lower frame portion112, which is a frame member disposed along the floor surface. In addition, the battery box223is provided to the vertical frame portions111. For example, the battery box223is supported by the pair of sub-frames1112of the vertical frame portions111. Further, in the lower frame portion112, the pair of main frames1121extend in a forward direction obliquely toward the center such that the distance therebetween in the width direction on the front side is narrowed. Therefore, the frame11is formed to have a narrow front-side width and a wide rear-side width in the direction of forward movement of the cart2. The basket portion12is formed in a box shape that is open upward by, for example, a perforated panel member or a mesh-shaped wire member. The basket portion12is formed to be capable of housing commodities or to be capable of placing a shopping basket for housing commodities. The basket portion12is disposed at a height spaced upward from the floor surface in front of the vertical frame portions111. The right and left sides of the rear end portion of the basket portion12are supported by the vertical frame portions111. The front wheel casters151and the rear wheel casters152each have a wheel153that rotates in the moving direction, and a bracket portion154that rotatably supports the wheel153. The bracket portion154is rotatably mounted to the frame11. As the wheels153of the casters151and152rotate on the floor surface, the cart2moves. Further, the traveling direction of the cart2can be changed by the rotation of the bracket portions154of the casters151and152. As in the case of the shapes of the frame11and the basket portion12, the front wheel casters151on the front side are disposed so as to have a narrower width therebetween than the width between the rear wheel casters152on the rear side. Therefore, for example, when the plurality of carts2are connected before and behind to be housed in the cart base3in series (seeFIG.1), the frame11of a cart2on the rear side can be housed so as to overlap along the frame11of a cart2on the front side. The electronic device21is an information terminal such as a tablet terminal for providing information to a user, or a commodity reader for acquiring information on a commodity selected by the user. The electronic device21is connected to, for example, the battery22. The electronic device21is driven by the power supplied from the battery22. The electronic device21may be, for example, a charger for charging an electronic device of a portable terminal owned by a user, such as a mobile phone, a smartphone, or a digital camera, with the power supplied from the battery22. In this embodiment, for example, the electronic device21includes a tablet terminal211and a commodity reader212. The tablet terminal211is a computer including a display unit provided with a touch panel. The tablet terminal211is installed with the display unit facing a user who is close to the handle portion114. The tablet terminal211displays, for example, information of a commodity read by the commodity reader212. Further, the tablet terminal211may perform checkout processing of the commodity read by the commodity reader212. The commodity reader212is a device that reads information of a commodity. Further, the commodity reader212may include a display unit that displays information of the read commodity. The commodity reader212is, for example, a radio-frequency identification (RFID) tag reader that reads an RFID tag or the like attached to a commodity to be taken in and out of the basket portion12. Further, the commodity reader212may be a scanner that reads commodity identification information such as a bar code attached to a commodity. Note that the electronic device21may be an interface device for connecting a portable terminal (a smartphone, a tablet terminal, or the like) owned by a user in place of the tablet terminal211. The portable terminal connected to the interface device serving as the electronic device21may perform processing similar to that of the tablet terminal211described above. Further, the interface device serving as the electronic device21may charge a battery included in the portable terminal. Note that the interface device serving as the electronic device21may include a built-in battery22or may be connected to a battery22separately provided. The battery box223is provided to the frame11. The battery box223is fixed to and supported by, for example, the pair of sub-frames1112disposed below an opening and closing panel121of the basket portion12. The battery22is a power supply device that supplies power to the electronic device21mounted on the cart2, and includes a charging circuit221and a secondary battery222as shown inFIG.3. The battery22is connected to the power reception device23and is charged by the power reception device23. The charging circuit221supplies the power, which is supplied from a switching circuit2324of the power reception device23to the secondary battery222, as power for charging (charging power). For example, the charging circuit221converts the power supplied from the switching circuit2324into a direct current (charging power) to be used for charging the secondary battery222. In other words, the charging circuit221converts the power supplied from the switching circuit2324into the charging power having a predetermined current value and a predetermined voltage value for charging the secondary battery222, and supplies the charging power to the secondary battery222. The charging circuit221charges the secondary battery222by the power supplied from the power reception device23. The secondary battery222is charged by the charging power supplied from the charging circuit221. Further, the secondary battery222is connected to the electronic device21and supplies power to the electronic device21. The power reception device23receives power transmitted in a non-contact manner, and supplies the received power to the electronic device21or the battery22. Note that the power reception device23may be configured to include an output terminal that supplies power to the electronic device21. In this case, the battery22may be configured to be charged by the power supplied through the electronic device21. The power reception device23is provided at the lower portion of the cart2. The power reception device23is disposed below the lower frame portion112, for example. When the cart2is kept (housed) in the cart base3, the power reception device23faces any one of the plurality of power transmission devices35provided in the cart base3(seeFIG.1). As shown inFIG.4, the power reception device23includes, for example, a casing230, a power reception coil231, and a power reception substrate. The casing230is, for example, a rectangular casing and houses the power reception coil231and the power reception substrate therein. The casing230is provided below the lower frame portion112, for example. As a specific example, the casing230is fixed to the mounting portion1125of the lower frame portion112. The lower surface of the casing230is disposed on the cart2at a posture along the floor surface on which the cart2travels. The casing230has a shape that does not overlap with the casings230of power reception devices23of carts2adjacent before and behind in the direction of the forward movement of the cart2when the plurality of carts2are stacked and kept in the cart base3in series (seeFIG.1). Further, the casing230is disposed at a position that does not overlap with or interfere with the power reception devices23of carts2adjacent before and behind in the direction of the forward movement of the cart2when the plurality of carts2are stacked and kept in the cart base3in series. The power reception coil231is disposed in the casing230. The power reception coil231is, for example, a planar coil formed by winding a litz wire. Alternatively, the power reception coil231is a planar coil obtained by forming a winding wire as a coil pattern on a printed circuit board. The power reception coil231has, for example, a flat power reception surface for receiving power. The power reception surface of the power reception coil231is disposed so as to face the floor surface on which the cart2travels. Note that the power reception coil231is not limited to the planar coil as long as it can perform power transmission with the power transmission device35. The power reception coil231is electromagnetically coupled to a power transmission coil351when the power reception device23faces the power transmission device35. The power reception coil231generates an induced current by the magnetic field output from the power transmission coil351of the power transmission device35. The power reception coil231constitutes, for example, a power reception resonance circuit (resonance element). Here, the power reception resonance circuit functions as, for example, an alternating current (AC) power supply that supplies AC power to a rectifier circuit2322connected to the power reception resonance circuit. For example, when a magnetic field resonance method is used for power transmission, it is desirable that the resonance frequency of the power reception resonance circuit be the same as or substantially the same as the resonance frequency of a power transmission resonance circuit constituted by the power transmission coil351, which will be described later, of the power transmission device35. This improves the power transmission efficiency when the power reception resonance circuit and the power transmission resonance circuit are electromagnetically coupled to each other. Note that the power reception resonance circuit may be configured to use an electromagnetic induction method for power transmission. As shown inFIG.3, the power reception substrate of the power reception device23includes the rectifier circuit2322, voltage conversion circuits2323, a switching circuit2324, and a control circuit2326. The power reception substrate mounts, for example, electronic components and wiring patterns, thus constituting various processing circuits including the rectifier circuit2322, the voltage conversion circuits2323, the switching circuit2324, the control circuit2326, and the like. The rectifier circuit2322rectifies the AC power supplied from the power reception resonance circuit constituted by the power reception coil231, and converts the AC power into direct current (DC) power. The rectifier circuit2322includes, for example, a rectifier bridge formed of a plurality of diodes. A pair of input terminals of the rectifier bridge is connected to the power reception resonance circuit. The rectifier circuit2322performs full-wave rectification of the AC power supplied from the power reception resonance circuit to output DC power from a pair of output terminals. The rectifier circuit2322supplies the DC power to the voltage conversion circuits2323. The voltage conversion circuit2323converts a DC voltage output from the rectifier circuit2322into a desired DC voltage. For example, two voltage conversion circuits2323are provided. Description will be given on one voltage conversion circuit2323referred to as a voltage conversion circuit23231and the other voltage conversion circuit2323referred to as a voltage conversion circuit23232. The one voltage conversion circuit23231is connected to, for example, the rectifier circuit2322and the switching circuit2324. The one voltage conversion circuit23231converts the DC power supplied from the rectifier circuit2322into DC power having a voltage suitable for the charging processing. The other voltage conversion circuit23232is connected to the rectifier circuit2322and the control circuit2326. The other voltage conversion circuit23232converts the DC power supplied from the rectifier circuit2322into the DC power suitable for the voltage for operating the control circuit2326. The switching circuit2324switches connection and disconnection between the voltage conversion circuit23231and the charging circuit221. The switching circuit2324switches connection and disconnection between the voltage conversion circuit23231and the charging circuit221on the basis of, for example, a signal from the control circuit2326. The control circuit2326controls the operation of the switching circuit2324. The control circuit2326is a processing circuit. The control circuit2326includes, for example, a processor and a memory. The processor executes arithmetic processing. The processor performs various types of processing on the basis of, for example, programs stored in the memory and data used in the programs. The memory stores programs, data used in the programs, and the like. The control circuit2326may include a microcomputer, an oscillation circuit, and/or the like. As shown inFIGS.1and2, the cart2is housed in the cart base3provided at a predetermined housing position. InFIGS.1and2, the plurality of carts2are housed in the cart base3in a nested manner. As shown inFIG.1, the cart base3as a housing apparatus for housing the carts2includes a guide base31as a base portion, a cart gate32, and the plurality of power transmission devices35supported by the guide base31. The guide base31includes a plate-shaped support base311that is laid at a predetermined housing position. The support base311includes, on its upper surface, a plurality of guide rails312extending in one direction and guide grooves313formed between the plurality of guide rails312. Further, the support base311includes projections and grooves for guiding the plurality of carts2to the housing position. The guide base31guides the travel of the cart2on the support base311by restricting the movement of the front and rear wheels153of the cart2by the guide rails312and the guide grooves313. Further, the guide base31supports the plurality of power transmission devices35at regular intervals. The cart gate32includes a pair of poles322vertically provided from both side portions of the guide base31, and side bars323disposed at predetermined heights at both side edges of the guide base31and extending in one direction. For example, the plurality of power transmission devices35are provided between the pair of guide grooves313of the guide base31, in which the pair of front wheels153of the cart2is guided. The plurality of power transmission devices35are disposed side by side in the extending direction of the pair of guide grooves313of the guide base31. Here, the extending direction of the guide grooves313is a traveling direction of the cart2in the guide base31. In other words, the extending direction of the guide grooves313is a stacking direction of the plurality of carts2in the guide base31. The plurality of power transmission devices35face the power reception devices23of the plurality of carts2stacked and kept in the cart base3. The power transmission device35transmits power to the power reception device23of the cart2opposed thereto in a non-contact manner. As shown inFIG.4, the power transmission device35includes, for example, a casing350, the power transmission coil351, a power transmission substrate, and an AC adaptor354(seeFIG.3). The casing350is formed in a rectangular box shape, for example. The casing350houses the power transmission coil351and the power transmission substrate therein. The casing350faces the power reception device23of the cart2housed in the cart base3with a predetermined interval therebetween. The distance between the casing350and the casing230of the power reception device23is several mm, as a specific example, 1 mm to 10 mm. The power transmission coil351is, for example, a planar coil formed by winding a litz wire. Alternatively, the power transmission coil351is a planar coil obtained by forming a winding wire as a coil pattern on a printed circuit board. The power transmission coil351has, for example, a flat power transmission surface for transmitting power. The power transmission surface of the power transmission coil351is disposed along the floor surface on which the cart2travels. Further, the power transmission surface of the power transmission coil351extends along the power reception surface of the power reception coil231provided to the opposed cart2housed in the cart base3. The power transmission coils351of the plurality of power transmission devices35are provided at positions facing the power reception coils231of the power reception devices23of the plurality of carts2housed in the cart base3. When the power reception device23and the power transmission device35face each other, the power transmission coil351is electromagnetically coupled to the power reception coil231. The power transmission coil351constitutes, for example, a power transmission resonance circuit (resonance element) as a power transmission unit. Here, it is desirable that the resonance frequency of the power transmission resonance circuit constituted by the power transmission coil351be the same as or substantially the same as the oscillation frequency of an oscillation circuit of a control circuit3528. This improves the power transmission efficiency when the power reception resonance circuit and the power transmission resonance circuit are electromagnetically coupled to each other. Note that the power transmission resonance circuit may use an electromagnetic induction method for power transmission. The power transmission substrate includes a power transmission circuit3522, a voltage conversion circuit3523, a switching circuit3524, a current sensor3526, a current detection circuit3527, and the control circuit3528. The power transmission substrate mounts, for example, electronic components and wiring patterns, thus constituting various processing circuits including the power transmission circuit3522, the voltage conversion circuit3523, the switching circuit3524, the current sensor3526, the current detection circuit3527, the control circuit3528, and the like. The power transmission circuit3522generates transmission power and supplies the generated transmission power to the power transmission coil351. For example, the power transmission circuit3522generates AC power as transmission power by switching the DC power supplied via the AC adaptor354or the like under the control of the control circuit3528. The power transmission coil351outputs power, which can be received by the power reception device23, in accordance with the transmission power supplied from the power transmission circuit3522. The power transmission circuit3522generates AC power having the same or substantially the same frequency as the resonance frequency of the power transmission resonance circuit. The power transmission circuit3522includes a switching element such as a field-effect transistor (FET). The power transmission circuit3522switches on and off by the output of the oscillation circuit of the control circuit3528. The power output from the power transmission circuit3522is transmitted to the power reception device23by using electromagnetic coupling such as electromagnetic induction or magnetic field resonance between the power transmission coil351and the power reception coil231. The voltage conversion circuit3523converts, for example, a voltage of a DC power supply, which is supplied via the AC adaptor354or the like connected to a commercial power supply, into a desired DC voltage. As a specific example, the voltage conversion circuit3523generates power for operating the control circuit3528and supplies the power to the control circuit3528. The switching circuit3524switches connection and disconnection between the AC adaptor354and the power transmission circuit3522. The switching circuit3524switches the state of power supply from the power transmission device35to the power reception device23by connecting or disconnecting the AC adaptor354and the power transmission circuit3522on the basis of the control signal from the control circuit3528. For example, the switching circuit3524supplies either the DC power of the voltage supplied from an external DC power source or the DC power of the voltage obtained by stepping down the DC power supplied from the external DC power source by the voltage conversion circuit3523to the power transmission circuit3522. The switching circuit3524switches the DC power to be supplied to the power transmission circuit3522under the control of the control circuit3528. The current sensor3526detects a direct current input to the power transmission circuit3522. The current sensor3526is a minute resistance connected between the switching circuit3524and the power transmission circuit3522. The current sensor3526generates a potential (current detection signal) corresponding to the current transmitted from the switching circuit3524to the power transmission circuit3522. The current detection circuit3527amplifies the minute signal detected by the current sensor3526and outputs the amplified minute signal to the control circuit3528. The current detection circuit3527measures a current value input to the power transmission circuit3522, for example. Note that the current value input to the power transmission circuit3522may be measured by the current sensor3526or by the current sensor3526and the current detection circuit3527. The control circuit3528controls the operation of the power transmission circuit3522. The control circuit3528is a processing circuit. The control circuit3528includes, for example, a processor and a memory. The processor executes arithmetic processing. The processor performs various types of processing on the basis of, for example, programs stored in the memory and data used in the programs. The memory stores programs, data used in the programs, and the like. The control circuit3528may include a microcomputer, an oscillation circuit, and/or the like. For example, the control circuit3528controls the frequency of the AC power output from the power transmission circuit3522and controls ON and OFF of the operation of the power transmission circuit3522. For example, the control circuit3528controls the switching circuit3524to switch between a state in which a magnetic field is generated in the power transmission coil351(power transmission state) and a state in which a magnetic field is not generated in the power transmission coil351(standby state). Further, the control circuit3528may control the power transmission coil351to intermittently generate a magnetic field to change the timing of power transmission. When power is supplied from the AC adaptor354and is turned on, the control circuit3528measures a standby current in the standby state (at the standby time) of the power transmission unit after the power is turned on by the current sensor3526and/or the current detection circuit3527, and sets the measured current value as a reference value A. Alternatively, the control circuit3528measures a standby current in the standby state after stopping the power transmission to the power reception device23by the current sensor3526and/or the current detection circuit3527, and sets the measured current value as a reference value A. For example, the processor of the control circuit3528stores the set reference value A in the memory. As a specific example, the control circuit3528operates the power transmission unit at the same power supply voltage as that in the standby state, measures the transmission current by a predetermined number of times n at predetermined intervals s, calculates an average value thereof, and sets the average value as a reference value A. For example, as shown in the diagram for describing the relationship between the time and the transmission current (power) inFIG.7, when the power transmission device35is turned on and is in the standby state, the standby current, which is a current equivalent to the reference value A, flows through the power transmission circuit3522. At that time, since the current value of the standby current fluctuates within a predetermined range, the control circuit3528estimates a reference value A by measuring the current value by a predetermined number of times n at predetermined intervals s and calculating an average value thereof. Further, as shown in the diagram for describing the relationship between the time and the transmission current (power) inFIG.8, the standby current (reference value A) of each power transmission device35differs, as indicated by the solid lines (1) to (3), depending on the variations in the characteristics of the power transmission devices35and the installation environments of the power transmission devices35. Therefore, the reference value A is obtained for each power transmission device35. Here, (1) to (3) inFIG.8are used for convenience to identify three different power transmission devices35. Further, (1)A to (3)A inFIG.8represent the current values (standby currents, reference values A) of the respective power transmission devices35in the standby state, and (1)T to (3)T represent foreign matter detection thresholds of the respective power transmission devices35. Note that the memory of the control circuit3528stores the predetermined intervals s and number of times n, which have been preset. Here, an example of the predetermined intervals s is 0.5 seconds, and the predetermined number of times n is a plurality of times, for example, ten times. In this example, the control circuit3528measures the standby current ten times at intervals of 0.5 seconds, calculates an average value A of those measured current values, and stores the calculated average value A as a reference value A in the memory. Further, when the power reception device23faces the power transmission device35, the control circuit3528performs authentication processing of confirming whether or not the power reception device23is a regular power reception device23. Further, the control circuit3528performs foreign matter detection processing of detecting a metal foreign matter located between the power transmission device35and the power reception device23. Here, the metal foreign matter is one, at least a part or all of which is formed of a metal material. Further, the metal foreign matter is present between the power reception device23and the power transmission device35and present on the power transmission coil351, and generates heat when the power transmission coil351transmits power. Examples of the metal foreign matter include various kinds of foreign matters such as coins, metal pieces, paper pieces or resin films including a metal film of aluminum or the like, clips, and hairpins. For example, the memory of the control circuit3528stores a threshold U, which is a predetermined value for determining whether or not the calculated reference value A is normal. If the reference value A is within the range of the threshold U, the control circuit3528determines that the reference value A is normal, and if the reference value A is larger than the threshold U, the control circuit3528determines that the reference value A is abnormal. Further, the control circuit3528sets a foreign matter detection threshold T, which is a value larger than the reference value A and is assumed to be generated when a metal foreign matter is present on the power transmission device35, on the basis of the calculated reference value A. The processing of setting the foreign matter detection threshold T by the control circuit3528is performed during the standby state, for example, after the power is turned on and before the power transmission to the power reception device23is started. Note thatFIG.7shows an example of the foreign matter detection threshold T by a broken line. As first processing of setting the foreign matter detection threshold T, the control circuit3528sets the foreign matter detection threshold T based on the reference value (average value) A, for example, when it is determined that the reference value A is normal. Further, as indicated by (1)A to (3)A inFIG.8, the reference value A is different for each power transmission device35. Hence, as indicated by (1)T to (3)T inFIG.8, the control circuit3528of each power transmission device35sets a foreign matter detection threshold T on the basis of the reference value A of each power transmission device35, that is, on the basis of the reference value A actually measured for each power transmission device35. As a specific example, the control circuit3528sets a current value A+α obtained by adding a constant value a to the reference value A as the foreign matter detection threshold T, and stores it in the memory. Further, as another specific example, the control circuit3528stores a current value obtained by adding a constant ratio β to the reference value A as the foreign matter detection threshold T in the memory. Here, the current value obtained by adding a constant ratio β to the reference value A is a value (A+A·β), which is obtained by adding a value obtained by multiplying the reference value A by a constant ratio β to the reference value A, and when the constant ratio β is 10% (0.1), the foreign matter detection threshold T is A×1.1. Note that the memory of the control circuit3528stores the constant value a and/or the constant ratio β for setting the foreign matter detection threshold T on the basis of the reference value A. Further, for example, as second processing of setting the foreign matter detection threshold T, if the reference value A is determined to be abnormal, the control circuit3528sets a fixed value C, which is a predetermined value of a preset current value, as the foreign matter detection threshold T, and stores the fixed value C in the memory. Here, the fixed value C is a current value larger than the reference value A and is assumed to be generated when a metal foreign matter of a predetermined size is present on the power transmission device35. Here, examples of the metal foreign matter having a predetermined size include an iron piece having a size of 20 mm square, but the metal foreign matter is not limited to this example. The current value set as a fixed value C is appropriately set on the basis of the size and type of the metal foreign matter to be detected. As an example, the fixed value C is set to a value in which variations in the standby current caused by variations of the power transmission device35, installation conditions, and the like are assumed, that is, a value with which a metal foreign matter can be determined by any of the power transmission devices35. In the example ofFIG.8, the fixed value C is set to, for example, a current value of (1)T such that a foreign matter can be detected by the power transmission device35having the highest current value (inFIG.8, (1)A) of the standby current (reference value A) among the assumed power transmission devices35. Such a fixed value C is then used for all the power transmission devices35. As described above, as the processing of setting the foreign matter detection threshold T, the control circuit3528sets the foreign matter detection threshold T on the basis of the reference value A calculated for each power transmission device35or sets a preset fixed value C if the reference value A cannot be used due to abnormality. As the foreign matter detection processing, the control circuit3528compares the foreign matter detection threshold T set in the first setting processing or the second setting processing with the current value detected by the current sensor3526and/or the current detection circuit3527, and detects the foreign matter. For example, as indicated by a dashed-dotted line inFIG.7, when a metal foreign matter is disposed on the power transmission device35, the current value fluctuates with a fluctuation value larger than the standby current. When the current value detected by the current sensor3526and/or the current detection circuit3527exceeds the foreign matter detection threshold T and is different from a normal current value, such as when the power reception device23is not authenticated, the control circuit3528determines that a metal foreign matter has been detected. When determining that the metal foreign matter is detected, the control circuit3528controls the switching circuit3524to enter a power transmission stop state in which a magnetic field is not generated in the power transmission coil351, and prevents overheating of the metal foreign matter. Further, when the metal foreign matter is not detected and the power reception device23is authenticated, the control circuit3528controls the switching circuit3524to generate a magnetic field corresponding to the transmission power in the power transmission coil351and to transmit power to the power reception device23. Note that, as shown inFIG.7, when no foreign matter is detected after the authentication of the power reception device23is established, the control circuit3528transmits power from the power transmission device35to the power reception device23and transfers to the charging operation. As in those examples, the control circuit3528controls each configuration and performs various types of processing on the basis of information such as various programs and parameters stored in the memory. The AC adaptor354is disposed outside the casing350, for example, and is connected to the power transmission substrate. Next, an example of the method of controlling the power transmission device35of the power supply system1according to this embodiment will be described with reference toFIGS.5and6.FIG.5is a flowchart showing a series of processing relating to the power transmission by the power transmission device35.FIG.6is a flowchart showing processing relating to setting of a foreign matter detection threshold. Note that, in this embodiment, an example is provided in which the authentication processing and the foreign matter detection processing are performed with the standby current, but the current for authentication and the current for foreign matter detection may have different current values. As shown inFIG.5, when the power transmission device35is turned on, in ACT1, the control circuit3528first performs the setting processing of setting the foreign matter detection threshold T. As shown inFIG.6, the control circuit3528performs processing of ACT11to ACT14as the processing of setting the foreign matter detection threshold T. First, in ACT11shown inFIG.6, the control circuit3528takes in a current value. The control circuit3528then calculates a reference value A as an average value. As a specific example, the control circuit3528measures the current value by a predetermined number of times n at predetermined intervals s, which are stored in the memory. The control circuit3528calculates the average value A from the measured current values. The control circuit3528sets the average value A as the reference value A and stores the average value A in the memory. Next, in ACT12, the control circuit3528compares the calculated reference value A with the threshold U stored in the memory. The control circuit3528then determines whether or not the reference value A is normal as the current value of the standby current. When the reference value A is normal (Yes in ACT12), the processing of the control circuit3528proceeds to ACT13. In ACT13, the control circuit3528sets a current value (A+α) obtained by adding a constant value a to the reference value A as the foreign matter detection threshold T or sets a current value (A+A·β) obtained by adding a constant ratio β to the reference value A as the foreign matter detection threshold T, and stores it in the memory. When the reference value A is abnormal (No in ACT12), the processing of the control circuit3528proceeds to ACT14. In ACT14, the control circuit3528sets the fixed value C stored in the memory as the foreign matter detection threshold T and stores it in the memory. Through the processing of ACT11to ACT14, the control circuit3528sets the foreign matter detection threshold T as ACT1. Next, in ACT2, the control circuit3528keeps the standby state until the authentication processing is performed, and then performs the foreign matter detection processing. For example, as the standby state, the control circuit3528continues power transmission from the power transmission coil351with the standby current. Further, during the standby state, as the foreign matter detection processing, the control circuit3528compares the current value detected by the current sensor3526and/or the current detection circuit3527with the set foreign matter detection threshold T. If the current value detected by the current sensor3526and/or the current detection circuit3527does not exceed the foreign matter detection threshold T, the control circuit3528continues the standby state by determining that a metal foreign matter is not detected. Note that if the current value detected by the current sensor3526and/or the current detection circuit3527exceeds the foreign matter detection threshold T, the control circuit3528determines that a metal foreign matter is detected, and stops power transmission, for example. Next, in ACT3, when the power reception device23faces the power transmission device35, the control circuit3528performs the authentication processing for confirming whether or not the power reception device23is a normal power reception device23. For example, the control circuit3528performs, as a load modulation method, a load modulation corresponding to the ID in the power reception unit, and detects the change in the current corresponding to the ID on the power transmission side, thus performing the authentication. Note that the control circuit3528may perform authentication determination by inquiring and answering the ID between the power transmission device and the power reception device by using a wireless communication means such as wireless communication or infrared communication. Next, in ACT4, it is determined whether or not the power reception device23facing the power transmission device35is a normal power reception device as a result of the confirmation in the authentication processing. If it is determined that the power reception device23is a normal power reception device (Yes in ACT4), the processing of the control circuit3528proceeds to ACT5. In ACT5, the control circuit3528performs normal power transmission to the power reception device23, and starts to charge the secondary battery222. Specifically, the control circuit3528transmits power for a predetermined period of time at a current value for charging. On the other hand, if it is determined that the power reception device23is not a normal power reception device (No in ACT4), the control circuit3528does not start normal power transmission (charging) processing. The processing of the control circuit3528returns to the standby state of ACT2. After the charging is started in ACT5, the processing of the control circuit3528proceeds to ACT6. In ACT6, the control circuit3528determines whether or not a charging termination condition is satisfied. If it is determined that the charging termination condition is satisfied (Yes in ACT6), the processing of the control circuit3528processes to ACT7. In ACT7, the control circuit3528stops the power transmission by determining the termination of charging. After the power transmission is stopped, the processing of the control circuit3528returns to the standby state of ACT2. On the other hand, if it is determined that the charging termination condition is not satisfied (No in ACT6), the control circuit3528continues the charging processing. Here, the charging termination condition includes a case where the secondary battery222is fully charged or the power reception device23moves and is not present on the power transmission device35. According to the power transmission device35and the power supply system1configured as described above, the foreign matter detection threshold T for detecting the metal foreign matter can be set on the basis of the reference value A obtained by measuring the standby current after power is turned on, for example. Here, for example, the foreign matter detection threshold T is a value obtained by adding the constant value a to the reference value A or a value obtained by adding the constant ratio β to the reference value A. Thus, the power transmission device35can set, as the foreign matter detection threshold T, a slightly larger current value than the standby current in a state in which there is no metal foreign matter in the standby state for each power transmission device35. Therefore, regardless of variations in performance and characteristics of each power transmission device35or the environment in which each power transmission device35is installed, the power transmission device35can detect a foreign matter with high sensitivity and can suppress erroneous detection of a metal foreign matter. The standby current fluctuates depending on variations in characteristics of components (e.g., electronic components, coils, and the like) constituting the power transmission device35and the surrounding environment in which the power transmission device35is installed. Here, the surrounding environment of the place where the power transmission device35is installed is, for example, the material (iron, aluminum, wood, or the like) of the cart base3in which the power transmission device35is installed, the floor, or the like. However, since the power transmission device35uses the foreign matter detection threshold T in the foreign matter detection processing by using the reference value A obtained from the actual measurement value during the standby state, e.g., after the power-on of each installed power transmission device35, it is possible to detect a foreign matter with high sensitivity and to suppress erroneous detection of a metal foreign matter. Further, setting, as the reference value A, the average value A calculated from the current values detected by the predetermined number of times n at the predetermined intervals s also makes it possible to suppress the variations of the reference value A due to the fluctuating standby current. In other words, by setting the average value A as the reference value A on the assumption that the standby current fluctuates during the standby state, it is not necessary to set the foreign matter detection threshold with a certain margin in order to avoid erroneous detection of a foreign matter. Therefore, the power transmission device35can also detect a metal foreign matter having a small change in current, such as a metal foreign matter with a small size, without sacrificing the foreign matter detection sensitivity. Further, the power transmission device35compares the obtained reference value A with the threshold U to determine whether or not the reference value is normal, and sets the fixed value C as the foreign matter detection threshold T when the reference value is determined to be abnormal. Thus, the power transmission device35can prevent the foreign matter detection threshold T from being set on the basis of the reference value A, which is a higher current value than the normal current value due to the metal foreign matter when the metal foreign matter is present on the power transmission device35. According to the power transmission device35and the power supply system1of the embodiment described above, it is possible to achieve both highly sensitive foreign matter detection and suppression of erroneous detection by using the foreign matter detection threshold T, which is set on the basis of the reference value A obtained from the standby current, in the foreign matter detection processing. Note that the power transmission device35and the power supply system1are not limited to those exemplified in the embodiment described above. Next, a power transmission device35A and a power supply system1according to a second embodiment will be described with reference toFIGS.9and10. Note that, in the power transmission device35A and the power supply system1according to the second embodiment, the components similar to those of the power transmission device35and the power supply system1according to the first embodiment described above will be denoted by the same reference numerals, and detailed description thereof will be omitted. FIG.9is a perspective view showing the configurations of a power reception device23and the power transmission device35A of the power supply system1according to the second embodiment.FIG.10is a block diagram showing the configuration of a control system of the power supply system1according to the second embodiment. As shown inFIG.9, the power supply system1includes the power reception device23and the power transmission device35A. For example, a plurality of power transmission devices35A are provided in a cart base3that houses a plurality of carts2. For example, the plurality of power transmission devices35A are provided between a pair of guide grooves313of a guide base31, in which a pair of front wheels153of the cart2is guided. The plurality of power transmission devices35A are disposed side by side in the extending direction of the pair of guide grooves313of the guide base31. The plurality of power transmission devices35A face the power reception devices23of the plurality of carts2stacked and kept in the cart base3. The power transmission device35A transmits power to the power reception device23of the cart2opposed thereto in a non-contact manner. As shown inFIG.9, the power transmission device35A includes, for example, a casing350, a power transmission coil351, a power transmission substrate, an AC adaptor354, and a switch355. The switch355is an external trigger. As shown inFIG.9, the switch355is exposed to the outer surface side of the casing350and is provided to be operable from the outside. The switch355outputs information of the operation, as a signal, to a control circuit3528. The switch355is, for example, a push switch that outputs a signal to the control circuit3528by a pressing operation. The control circuit3528then performs setting processing of setting a foreign matter detection threshold T when receiving the signal indicating that the switch355is operated. Note that when the switch355is operated, the operator confirms that there is no metal foreign matter on the casing350and then operates the switch355. In other words, when the operator operates the switch355, the control circuit3528determines that the operator has confirmed that there is no metal foreign matter on the casing350of the power transmission device35A. The control circuit3528then sets the foreign matter detection threshold T on the basis of the calculated reference value A. Thus, if the foreign matter detection threshold T is set with the operation of the switch355as an external trigger, the control circuit3528does not perform the above processing of determining whether or not the reference value A is normal in ACT12and of setting the fixed value C to the foreign matter detection threshold T in ACT14. After calculating the reference value A (ACT11), the control circuit3528only needs to set the foreign matter detection threshold T on the basis of the reference value A (ACT13). With such a configuration, the power transmission device35A can perform the processing of setting the foreign matter detection threshold T after confirming that the power reception device23does not face the power transmission device35A and that there is no metal foreign matter on the power transmission device35A, with the operation of the switch355as a trigger for starting to set the foreign matter detection threshold T. This makes it possible for the power transmission device35A to set the foreign matter detection threshold T on the basis of a normal reference value A. As a result, the power transmission device35A can perform reliable threshold setting in addition to achieving both highly sensitive foreign matter detection and suppression of erroneous detection as in the first embodiment described above. Note that the power transmission device35A performs the processing of setting the foreign matter detection threshold in ACT11to ACT14of the first embodiment if the switch355is not operated for a predetermined period of time after the power is turned on or after the power transmission to the power reception device23is stopped. Further, the power transmission device35A may perform the processing of setting the foreign matter detection threshold in ACT11and ACT13of the second embodiment if the switch355is operated within a predetermined period of time. Next, a power transmission device35B and a power supply system1according to a third embodiment will be described with reference toFIGS.11to13. Note that, in the power transmission device35B and the power supply system1according to the third embodiment, components similar to those of the power transmission device35and the power supply system1according to the first embodiment and the power transmission device35A and the power supply system1according to the second embodiment described above will be denoted by the same reference numerals, and detailed description thereof will be omitted. FIG.11is a perspective view showing a configuration of the power transmission device35B of the power supply system1according to the third embodiment.FIG.12is a block diagram showing a configuration of a control system of the power supply system1according to the third embodiment.FIG.13is a flowchart showing an example of processing of setting a foreign matter detection threshold in the power supply system1according to the third embodiment. As shown inFIG.11, the power supply system1includes a power reception device23and the power transmission device35B. The power reception device23is provided in, for example, a cart2. For example, a plurality of power transmission devices35B are provided in a cart base3that houses the plurality of carts2. For example, the plurality of power transmission devices35B are provided between a pair of guide grooves313of a guide base31, in which a pair of front wheels153of the cart2is guided. The plurality of power transmission devices35B are disposed side by side in the extending direction of the pair of guide grooves313of the guide base31. The plurality of power transmission devices35B face the power reception devices23of the plurality of carts2stacked and kept in the cart base3. The power transmission device35B transmits power to the power reception device23of the cart2opposed thereto in a non-contact manner. As shown inFIGS.11and12, the power transmission device35B includes, for example, a casing350, a power transmission coil351, a power transmission substrate, an AC adaptor354, a switch355, and a display device356. As shown inFIG.11, the casing350includes a guide portion3501on a part of a region, which is the outer surface and in which the power transmission coil351is provided. The guide portion3501is a mark for indicating a specific location by printing, unevenness, a seal, or the like. The guide portion3501indicates a position where a metal test piece90for obtaining a foreign matter detection threshold T is disposed in the processing of setting the foreign matter detection threshold T by the control circuit3528. The switch355is an external trigger. As shown inFIG.11, the switch355is exposed to the outer surface side of the casing350and is provided to be operable from the outside. The switch355outputs information of the operation, as a signal, to a control circuit3528. The switch355is, for example, a push switch that outputs a signal to the control circuit3528by a pressing operation. The display device356displays or notifies information to the outside. As shown inFIG.11, the display device356is a display unit that is exposed to a part of the outer surface of the casing350to provide information in a manner visually recognizable from the outside of the casing350. As shown inFIG.12, the display device356is connected to the control circuit3528and performs specific display or notification on the basis of a command from the control circuit3528. The display device356is, for example, an LED. The display device356can emit light in a plurality of different colors. The display device356displays different types of information according to a display method such as a color to be displayed, lighting, turning off, and/or blinking. Note that the display device356is not limited to the LED and may be a display, a segment, or the like. The control circuit3528performs setting processing of setting the foreign matter detection threshold T as ACT1if receiving the signal indicating that the switch355is operated. In performing the processing of setting the foreign matter detection threshold T, the control circuit3528detects a current value that is increased more than the standby current due to the metal test piece90artificially disposed on the guide portion3501, for example, with the operation of the switch355as a trigger. The control circuit3528then sets the detected current value or a current value lower than the detected current value and higher than the standby current as the foreign matter detection threshold T. Such procedure of the operation of the switch355and the arrangement of the metal test piece90in the processing of setting the foreign matter detection threshold T is appropriately determined by the method of controlling the control circuit3528. For example, the following control may be performed, in which the metal test piece90is disposed on the guide portion3501when the operator operates the switch355or within a predetermined period of time after the operator operates the switch355. Further, for example, the operator may confirm that the processing of setting the foreign matter detection threshold T is being performed on the basis of the display of the display device356, and then operate the switch355after placing the metal test piece90on the guide portion3501. Next, an example of the processing of setting the foreign matter detection threshold (ACT1) by the power transmission device35B configured as described above will be described with reference to the flowchart ofFIG.13. When the power supply is turned on, the control circuit3528starts to set the foreign matter detection threshold T (ACT1). As a specific example, as shown inFIG.13, the control circuit3528first takes in a current value in ACT21as the processing of setting the foreign matter detection threshold T. The control circuit3528then calculates a reference value A that is an average value. As a specific example, the control circuit3528measures a current value that is a standby current by a predetermined number of times n at predetermined intervals s, which are stored in the memory. The control circuit3528calculates an average value A from the measured current values. The control circuit3528sets the average value A as the reference value A, and stores it in the memory. Next, in ACT22, the control circuit3528controls the display device356to turn on or blink the LED in a predetermined color, for example. Thus, the control circuit3528notifies the outside of the fact that the foreign matter detection threshold T is being set. Note that the operator who performs the processing of setting the foreign matter detection threshold T disposes the metal test piece90on the guide portion3501and operates the switch355. In ACT23, upon receiving a signal from the switch355, the control circuit3528determines that the installation of the metal test piece90has been completed. The control circuit3528then measures the current by a current sensor3526and/or a current detection circuit3527, and detects a current value D that becomes the foreign matter detection threshold T. Here, the current value D is the maximum value of the current detected within a predetermined period of time t, or an average value calculated from the current values detected by the predetermined number of times n at the predetermined intervals s. Note that the memory of the control circuit3528stores the predetermined period of time t, the predetermined intervals s, and/or the predetermined number of times n, which are preset. Further, the predetermined intervals s and the predetermined number of times n of this embodiment may be the same as or different from the predetermined intervals s and the predetermined number of times n for determining the reference value A. In addition, in ACT24, the control circuit3528sets the obtained current value D to the foreign matter detection threshold T. Subsequently, in ACT25, the control circuit3528then controls the display device356to notify the outside of the fact that the setting of the foreign matter detection threshold T has been completed. Note that, here, the control circuit3528notifies the outside of the completion of the setting of the foreign matter detection threshold T, in a manner different from the display method for the display device356in ACT22. For example, in ACT25, the control circuit3528may turn off the LED or change the color of the LED. The control circuit3528then performs ACT2and subsequent processing. With such a configuration, the power transmission device35B can set the foreign matter detection threshold T on the basis of the metal test piece90for each power transmission device35B, so that both highly sensitive foreign matter detection and suppression of erroneous detection can be achieved. Since the target value of the foreign matter detection threshold T can be set depending on the shape or material of the metal test piece90, the power transmission device35B can set the foreign matter detection threshold T in consideration of the size or the like of the metal foreign matter to be detected. Note that, depending on the shape or the like of the power transmission coil351, the amount of heat generated by the metal foreign matter may vary with the position of the metal foreign matter on the power transmission coil351even if the same metal foreign matter is used. In other words, the current flowing in the power transmission coil351may differ depending on the relative positions of the metal foreign matter and the power transmission coil351. Hence, if the position on the casing350on which the guide portion3501is displayed is set on the basis of the current value of the current flowing by the metal foreign matter, it is possible to manage the threshold when the metal test piece90is disposed in the guide portion3501. Accordingly, the sensitivity can be set to be high or low depending on the position where the guide portion3501is provided. Note that the position where the guide portion3501is provided may be the center of the power transmission coil351or a position deviated from the center. Specifically, the position may be a position deviated from the center of the power transmission coil351and directly above the coil copper wire. Further, the following configuration may be adopted, in which the guide portions3501are provided at a plurality of locations where the amount of heat generation of the metal foreign matter differs, to select a position where the metal test piece90is to be disposed on the basis of the foreign matter detection thresholds T to be set by the plurality of guide portions3501. Note that, for example, the power transmission device35B may obtain the reference value A (ACT21) as the processing of setting the foreign matter detection threshold T (ACT1), and then determine whether or not the reference value A is normal to be the current value of the standby current as shown in ACT12. In such a configuration, the control circuit3528only needs to perform the processing of ACT22and subsequent processing when it is determined that the reference value A is normal, and to set the fixed value C to the foreign matter detection threshold T as shown in ACT14when it is determined that the current value is abnormal. Further, for example, the power transmission device35B performs the processing of setting the foreign matter detection threshold in ACT11to ACT14of the first embodiment when the switch355is not operated for a predetermined period of time after the power is turned on or after the power transmission to the power reception device23is stopped. Further, the power transmission device35B may perform the processing of setting the foreign matter detection threshold T using the metal test piece90when the switch355is operated within a predetermined period of time. Further, for example, when the display device356is displaying the information indicating that the foreign matter detection threshold T is being set, the power transmission device35B may be able to select either the processing of setting the foreign matter detection threshold T using the metal test piece90or the processing of setting the foreign matter detection threshold T in the second embodiment described above on the basis of the signal input by the different operation methods for the switch355. For example, if a signal corresponding to one short operation of the switch355is input, the control circuit3528determines that the processing of setting the foreign matter detection threshold T using the metal test piece90in the third embodiment has been selected. If a signal corresponding to two short operations of the switch355is input, the control circuit3528determines that the processing of setting the foreign matter detection threshold T in the second embodiment has been selected. Subsequently, the control circuit3528may perform the selected processing of setting the selected foreign matter detection threshold T. In other words, the power transmission device according to the embodiment may perform any processing of setting the foreign matter detection threshold T according to the embodiments described above or may selectively perform all types of the setting processing. Further, in the examples of the embodiments described above, a shopping cart has been described as an example, in which the power reception device23of the power supply system1that supplies power in a non-contact manner is used in the cart2. However, the cart2equipped with the power reception device23is not limited to a shopping cart, and may be, for example, a picking cart used in a warehouse or the like. Further, the power reception device23and the power transmission device35can also be applied to configurations other than the cart2and the cart base3as long as the power supply system1performs non-contact power supply. According to the power transmission device and the power supply system of at least one embodiment described above, setting the foreign matter detection threshold T on the basis of the reference value A obtained from the standby current makes it possible to achieve both highly sensitive foreign matter detection and suppression of erroneous detection. While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. | 71,240 |
11862993 | DETAILED DESCRIPTION Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise. Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. As used herein, a list with a conjunction of “and/or” includes any single item in the list or a combination of items in the list. For example, a list of A, B and/or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one or more of” includes any single item in the list or a combination of items in the list. For example, one or more of A, B and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one of” includes one and only one of any single item in the list. For example, “one of A, B and C” includes only A, only B or only C and excludes combinations of A, B and C. An apparatus for a high-power reflexive field containment circuit topology for dynamic wireless power transfer systems is disclosed. A wireless power transfer (“WPT”) charging apparatus includes an inverter configured to connect with a direct current (“DC”) source on an input side and one or more WPT charging branches. Each WPT charging branch includes a WPT charging pad circuit with a WPT charging pad connected in series with a first series charging capacitor, a parallel charging capacitor connected in parallel with the WPT charging pad circuit, and a series charging impedance connected in series between an output of the inverter and a connection between the WPT charging pad circuit and the parallel charging capacitor. The series charging impedance includes a second series charging capacitor and/or a series charging inductor. In some embodiments, the WPT charging apparatus also includes a WPT receiver apparatus that includes a rectification section with an output configured to connect to a load and a WPT receiver branch. The WPT receiver branch includes a WPT receiver pad connected in series with a first series receiver capacitor, a parallel receiver capacitor connected in parallel with a branch that includes the WPT receiver and first series receiver capacitor, and a second series receiver capacitor connected in series between a connection to the WPT receiver branch and an input of the rectification section. In some embodiments, the series charging impedance, the first series charging capacitor, the parallel charging capacitor, the first series receiver capacitor, the parallel receiver capacitor, and the second series receiver capacitor are related by a buck-boost factor n1relating the series charging impedance with the parallel charging capacitor, and by: n2=Cr,pCr,sb+1(n2>1)n3=Cr,pCr,sa+1(n3>1) where n1is a buck-boost factor of an equivalent input voltage at the output of the inverter, Cr,pis the parallel receiver capacitor, Cr,sbis the first series receiver capacitor, Cr,sais the second series receiver capacitor, n2is a ratio relating the parallel receiver capacitor to the first series receiver capacitor, and n3is a ratio relating the parallel receiver capacitor to the second series receiver capacitor. In other embodiments, the series charging impedance is the first series charging capacitor without the series charging inductor and where: n1=C1,pC1,sa+1(n1>0) where C1,pis the parallel charging capacitor, and C1,sais the second series charging capacitor. In other embodiments, the series charging impedance comprises the first series charging capacitor and the series charging inductor and where: n1=C1,pC1,sa′+1(n1>0) where: C1,sa′=C1,sa1+ω2L1,saC1,sa and where C1,sais second series charging capacitor, ω is an angular switching frequency of the inverter, C1,pis the parallel receiver capacitor, and L1,sais the series charging inductance. In other embodiments, the series charging impedance is the series charging inductor without the first series charging capacitor, and where: n1=−ω2L1,saC1,p+1(n1>0) where ω is an angular switching frequency of the inverter, C1,pis the parallel charging capacitor, and L1,sais the series charging inductance. In some embodiments, the buck-boost factor n1is less than 0.9 or greater than 1.1. In other embodiments, n3is greater than 1.1. In other embodiments, each of the one or more WPT charging branches includes an inductance of the WPT charging pad, capacitance of the first series charging capacitor, capacitance of the parallel charging capacitor selected to operate at resonance at a switching frequency of the inverter in response to the WPT receiver pad being uncoupled with the WPT charging pad. In other embodiments, the one or more WPT charging branches include two or more WPT charging branches and the WPT receiver pad of the WPT receiver apparatus moves across the WPT charging pads of the WPT charging branches in a direction perpendicular to a plane comprising the WPT charging pads. In other embodiments, the rectifier circuit includes a low pass filter. In other embodiments, the rectifier circuit includes an active rectifier circuit comprising switches. In other embodiments, the WPT charging pad and the WPT receiver pad are configured to transmit and receive power wirelessly. In other embodiments, the inverter includes a bandpass filter connected between an output of a switching section of the inverter and the output of the inverter. The bandpass filter includes a bandpass inductor in series with a bandpass capacitor where the bandpass filter is designed to pass a switching frequency of the inverter. A system for a high-power reflexive field containment circuit topology for dynamic wireless power transfer systems includes a WPT charging apparatus that includes an inverter configured to connect with a DC source on an input side, and a plurality of WPT charging branches. Each WPT charging branch includes a WPT charging pad circuit with a WPT charging pad connected in series with a first series charging capacitor, a parallel charging capacitor connected in parallel with the WPT charging pad circuit, and a series charging impedance connected in series between an output of the inverter and a connection between the WPT charging pad circuit and the parallel charging capacitor. The series charging impedance includes a second series charging capacitor and/or a series charging inductor. The system includes a WPT receiver apparatus with a rectification section that includes an output configured to connect to a load and a WPT receiver branch. The WPT receiver branch includes a WPT receiver pad connected in series with a first series receiver capacitor, a parallel receiver capacitor connected in parallel with a branch comprising the WPT receiver and first series receiver capacitor, and a second series receiver capacitor connected in series between a connection to the WPT receiver branch and an input of the rectification section. The WPT receiver pad is mobile with respect to each of the one or more the WPT charging pads. In some embodiments, the series charging impedance, the first series charging capacitor, the parallel charging capacitor, the first series receiver capacitor, the parallel receiver capacitor, and the second series receiver capacitor are related by a buck-boost factor n1relating the series charging impedance with the parallel charging capacitor, and by: n2=Cr,pCr,sb+1(n2>1)n3=Cr,pCr,sa+1(n3>1) where n1is a buck-boost factor of an equivalent input voltage at the output of the inverter, Cr,pis the parallel receiver capacitor, Cr,sbis the first series receiver capacitor, Cr,sais the second series receiver capacitor, n2is a ratio relating the parallel receiver capacitor to the first series receiver capacitor, and n3is a ratio relating the parallel receiver capacitor to the second series receiver capacitor. In some embodiments, the series charging impedance is the first series charging capacitor without the series charging inductor and where: n1=C1,pC1,sa+1(n1>0) where C1,pis the parallel charging capacitor, and C1,sais the second series charging capacitor. In other embodiments, the series charging impedance includes the first series charging capacitor and the series charging inductor and where: n1=C1,pC1,sa′+1(n1>0) where: C1,sa′=C1,sa1+ω2L1,saC1,sa and where C1,sais second series charging capacitor, ω is an angular switching frequency of the inverter, C1,pis the parallel receiver capacitor, and L1,sais the series charging inductance. In other embodiments, the series charging impedance is the series charging inductor without the first series charging capacitor and where: n1=−ω2L1,saC1,p+1(n1>0) where ω is an angular switching frequency of the inverter, C1,pis the parallel charging capacitor, and L1,sais the series charging inductance. In some embodiments, the buck-boost factor n1is less than 0.9 or greater than 1.1, and/or wherein the n3is greater than 1.1. In other embodiments, the inverter includes a bandpass filter connected between an output of a switching section of the inverter and the output of the inverter. The bandpass filter includes a bandpass inductor in series with a bandpass capacitor where the bandpass filter is designed to pass a switching frequency of the inverter. Another system for a high-power reflexive field containment circuit topology for dynamic wireless power transfer systems includes a WPT charging apparatus. The WPT charging apparatus includes an inverter configured to connect with a DC source on an input side and a plurality of WPT charging branches. Each WPT charging branch includes a WPT charging pad circuit with a WPT charging pad connected in series with a first series charging capacitor, a parallel charging capacitor connected in parallel with the WPT charging pad circuit, and a series charging impedance connected in series between an output of the inverter and a connection between the WPT charging pad circuit and the parallel charging capacitor. The series charging impedance includes a second series charging capacitor and a series charging inductor and a WPT receiver apparatus. The WPT receiver apparatus includes a rectification section with an output configured to connect to a load and a WPT receiver branch. The WPT receiver branch includes a WPT receiver pad connected in series with a first series receiver capacitor, a parallel receiver capacitor connected in parallel with a branch with the WPT receiver and first series receiver capacitor, and a second series receiver capacitor connected in series between a connection to the WPT receiver branch and an input of the rectification section. In the system, the WPT receiver pad is mobile with respect to each of the one or more the WPT charging pads, and n1=C1,pC1,sa′+1(n1>0)C1,sa′=C1,sa1+ω2L1,saC1,san2=Cr,pCr,sb+1(n2>1),n3=Cr,pCr,sb+1(n3>1) where C1,sais second series charging capacitor, ω is an angular switching frequency of the inverter, C1,pis the parallel receiver capacitor, L1,sais the series charging inductance, Cr,pis the parallel receiver capacitor, Cr,sbis the first series receiver capacitor, Cr,sais the second series receiver capacitor, n1is a buck-boost factor of an equivalent input voltage at the output of the inverter, n2is a ratio relating the parallel receiver capacitor to the first series receiver capacitor, and n3is a ratio relating the parallel receiver capacitor to the second series receiver capacitor. Reflexive field containment type switches resonated transmitter coils utilizing reflected impedance.FIG.1shows a concept of the reflexive field containment approach. The vehicle includes a WPT receiver apparatus with a WPT receiver coil mounted on the bottom of the vehicle. Typically, the WPT receiver apparatus is connected to a load of a battery, but the load could also include a motor, electronics, etc. This system has a common inverter and segmented transmitter coils. Each transmitter coil is connected to a resonator circuit which is detuned when a vehicle is not present. As a result, a low current will flow through the coils when no secondary circuit is present. However, when a vehicle is on top of the transmitter coil, the reflected impedance from the secondary side will tune the transmitter resonator circuit, allowing a large current to flow through the transmitter coils and therefore transfer power to the vehicle. As a result, the system can change the amplitude of the current in each transmitter coil automatically, even though all the transmitter coils are being excited by the same inverter. However, existing reflexive field containment circuits do not allow both the power output and gain of the transmitter coil to be designed simultaneously. Hence, it is difficult to achieve high output power while maintaining the desired gain of transmitter current. A new reflexive field containment circuit is discussed herein with more degrees of freedom is proposed for high-power dynamic wireless power transfer systems, such as automotive applications. I. PROPOSED REFLEXIVE FIELD CONTAINMENT TOPOLOGY The conventional reflexive field containment circuit topology is shown inFIG.2. The conventional circuit includes a bandpass filter formed by bandpass inductor Lfand bandpass capacitor Cfon the inverter side. The purpose of the bandpass filter is to reduce switching loss due to harmonics in the inverter current from the uncoupled transmitter coil branches. Each branch has a parallel compensation capacitor C1,p(also referred to herein as a “parallel charging capacitor”) and a series compensation capacitor C1,s(also referred to herein as a first series charging capacitor and with C2,pand C2,sin the second branch, . . . Cn,pand Cn,sin the nthbranch). On the receiver side, a series compensation capacitor Cr,s(also referred to herein as a “parallel receiver capacitor”) and a parallel compensation capacitor Cr,pare attached (also referred to herein as a “first series receiver capacitor”). The conventional circuit includes an output inductor Ldcbetween the secondary compensation circuit and the output voltage Vbat, since the parallel compensation capacitor Cr,pon the receiver can be assumed as a voltage source and switching action of the diode rectifier typically creates large current spikes if the output inductor Ldcis not attached between the parallel compensation capacitor Cr,pand the output voltage Vbatof the receiver. FIG.3Ais a circuit diagram illustrating a proposed reflexive field containment circuit topology with a series charging impedance with an inductor and a capacitor, according to various embodiments. The system ofFIG.3Aincludes a WPT charging apparatus on the left, which includes a DC source VDCconnected to an inverter, a bandpass filter that includes a bandpass inductor Lfand a bandpass capacitor Cf, and one or more WPT charging branches. In some embodiments, the WPT charging apparatus includes a rectifier and is connected to an alternating current (“AC”) source where the AC source is rectified to provide a DC voltage to the inverter. In the embodiment, the rectifier may be a full-bridge rectifier or a half-bridge rectifier and may be followed by a lowpass filter. In some embodiments, the WPT charging apparatus does not include the bandpass filter. Each WPT charging branch includes a WPT charging pad represented by L1, L2, . . . Ln, a first series charging capacitor C1,sb, C2,sb, . . . Cn,sb, a parallel charging capacitor C1,p, C2,p, . . . Cn,p, and a series charging impedance that includes a second series charging capacitor C1,sa, C2,sa, . . . Cn,saand a series charging inductor L1,sa, L2,sa, . . . Ln,sa. The inverter, in some embodiments, includes switches, such as metal-oxide-semiconductor field-effect transistors (“MOSFETs”). In some embodiments, the switches are in a full-bridge configuration. The inverter may also include a capacitor in parallel with the input terminals and may include other components, such as a lowpass filter. In some embodiments, the WPT charging apparatus includes one or more transformers, snubbers, zero-voltage switching controls and components, and the like. One of skill in the art will recognize other components compatible with the WPT charging apparatus. The system includes a WPT receiver apparatus that includes a compensation section connected to a rectification section, which connects to a load (not shown). The load is typically a battery of a vehicle, but may connect to a motor, electronics, controls, etc. The compensation section includes a WPT receiver pad, represented by inductor Lr, a first series receiver capacitor Cr,sb, a parallel receiver capacitor Cr,p, and a second series receiver capacitor Cr,sa. The rectification circuit, in some embodiments, includes a diode rectifier. In other embodiments, the rectification circuit includes active switches instead of diodes where the system has power flow that is bidirectional. In some embodiments, the rectification circuit includes a lowpass filter with a DC inductor LDCand a DC capacitor CDC. In other embodiments, the rectification section includes other components, such as snubbers, more components in the lowpass filter, an active converter section, a transformer, or the like. One of skill in the art will recognize other components compatible with the WPT receiver apparatus. The WPT charging pad and the WPT receiver pad are configured to have a gap between the pads. In some embodiments, the gap is at least partially air. In other embodiments, a portion of the gap is asphalt, resin, or other covering for the WPT charging pads, which are typically stationary and may be mounted in a roadway. Compared to the conventional circuit ofFIG.2, each branch has an additional series charging impedance with a compensation capacitor C1,sa(also referred to herein as a “second series charging capacitor”) and inductor L1,sa(also referred to herein as a “series charging inductor”) on the transmitter side, and an additional series compensation capacitor Cr,sa(also referred to as a “second series receiver capacitor”) at the receiver side. The purpose of the series compensation capacitor C1,saand inductor L1,saon the transmitter side is to decrease or increase an equivalent input voltage to the transmitter coils. By decreasing or increasing the equivalent input voltage, the proposed circuit can balance the current and voltage between the transmitter side and the receiver side components. As a result, the proposed circuit can achieve higher output power and higher efficiency compared to the conventional reflexive field containment circuit ofFIG.2. FIG.3Bis a circuit diagram illustrating a proposed reflexive field containment circuit topology with a series charging impedance with a capacitor, according to various embodiments. The series charging impedance includes the series compensation capacitor C1,sawithout an inductor. The circuit ofFIG.3Bis able to decrease the input equivalent voltage and decrease current in the WPT receiver pad.FIG.3Cis a circuit diagram illustrating a proposed reflexive field containment circuit topology with a series charging impedance with an inductor, according to various embodiments. The series charging impedance includes the inductor L1,sawithout a capacitor. The circuit ofFIG.3Cis able to increase the input equivalent voltage and to lower the WPT charging pad current. The series compensation capacitor Cr,saon the receiver side can increase the reflected impedance utilized for the reflexive field containment function. The additional series compensation capacitor Cr,sasolves the problem that the conventional reflexive field containment circuit needs to design output power and reflected impedance by only the ratio of Cr,pand Cr,sb. The proposed circuits ofFIGS.3A-3Chave more degrees of freedom in its design because of the additional series compensation inductors and capacitors in the transmitter and receiver sides. The benefit of the proposed reflexive field containment topology is that a higher power design can be achieved while maintaining uncoupled currents at the same level compared to the conventional circuit by selecting proper input equivalent voltage and reflected impedance utilizing the additional compensation components. II. THEORETICAL ANALYSIS OF THE PROPOSED CIRCUIT In this section, the equations of output power and other aspects of the proposed reflexive field containment circuit are derived. Additionally, the Pareto fronts of the proposed and conventional reflexive field containment circuits are analyzed. A. Fundamental Harmonic Analysis FIG.4is a circuit diagram illustrating an equivalent circuit during general conditions, according to various embodiments. The equivalent circuit is derived fromFIG.3Ais shown inFIG.4. For simplicity, only the first transmitter coil is considered in this analysis. To derive the relationship between the reflected impedance Zrefand compensation inductors and capacitors, circuit equations can be written in a matrix form as follows: [1jωC1,sa′+1jωC1,p-1jωC1,p-1jωC1,pjωL1′+1jωC1,p]·[i1,ai1,b]=[vin-vref](1)[1jωCr,p+1-jωCr,sa+Rload-1jωCr,p-1jωCr,pjωLr′+1jωCr,p]·[ir,air,b]=[voc0](2) where ω is the angular switching frequency of the inverter, vinis the equivalent input voltage, vrefis the reflected voltage, vocis the induced voltage, Rloadis the equivalent load resistance. C′1,sa, L′1, and L′rare represented by C1,sa′=C1,sa1-ω2L1,saC1,sa,(3)L1′=L1-1ω2C1,sb,(4)Lr′=Lr-1ω2Cr,sb.(5) The reflected voltage vrefand the induced voltage vocare depicted by the diamond mark since they are dependent voltage sources, and represented by: vref=−jωM1,rir,b(6) voc=jωM1,ri1,b(7) where M1,r=k1,r√{square root over (L1Lr)}. (8) M1,ris the mutual inductance between the WPT charging pad and the WPT receiver pad. The fundamental harmonic of the inverter voltage vinand the rectifier voltage voutare represented in phasor notation as: vin=4Vdcπejωt,(9)vout=4vbatπejωt.(10) Lfand Cfare tuned as a bandpass filter for the inverter switching frequency fswto reduce the switching loss at the inverter in the uncoupled condition. Lfand Cfcan be designed by: fsw=12πLfCf.(11) For the circuit ofFIG.3A, to reduce the number of design parameters in the proposed circuit, n1, n2, and n3are defined as follows. On the transmitter side, the ratio of C1,pand C′1,sais defined by: n1=C1,pC1,sa′+1(n1>0).(12) For the circuit ofFIG.3Bwhere the series charging impedance is the second series charging capacitor C1,sa, n1becomes: n1=C1,pC1,sa+1(n1>0).(12.1) For the circuit ofFIG.3Cwhere the series charging impedance is the second series charging inductor L1,sa, n1becomes: n1=−ω2L1,saC1,p+1(n1>0). (12.2) On the receiver side, the ratio of Cr,pand Cr,sbis defined by: n2=Cr,pCr,sb+1(n2>1).(13) The ratio of Cr,pand Cr,sais defined by n3=Cr,pCr,sa+1(n3>1).(14) Note that when n1=n3=1, the proposed circuit is identical to the conventional circuit. For the equations above, the reflected impedance by Zrefis represented by: Zref=vrefi1,b=-jωM1,rir,bi1,b.(15) At the receiver side, the resonant equation in the current loop ir,bshown inFIG.4is represented by: 1jωCr,p+jωLr′=0(16) From equations (13), (14), and (16), all the compensation parameters at the receiver side Cr,sb, Cr,p, Cr,saare represented by: Cr,sb=n2Lrω2(n2-1)(17)Cr,p=n2Lrω2(18)Cr,sa=n2Lrω2(n3-1)(19) From equations (1), (2), (15), (7), (17), (18), and (19), the reflected impedance Zrefis represented by: Zref=Rref-jXref=k1,r2L1Reqn22Lr-jωk1,r2L1n2n3.(20) From equation (20), we can see the imaginary part of the reflected impedance Zrefcan be designed by n2and n3. Since the resonant status of the transmitter coil (e.g., WPT charging pad) is changed according to the imaginary part of the reflected impedance, the current gain of the transmitter coil can be designed using n2and n3. FIG.5includes circuit diagrams illustrating conversions of equivalent circuits of a WPT charging apparatus during an uncoupled condition, according to various embodiments.FIG.5shows the equivalent circuit when inductance of the primary coil L1is uncoupled (k1,r=0), for example, when the WPT receiver pad is not close to the WPT charger pad.FIG.5(a)shows the resonant loop in the uncoupled condition. The reflected impedance Zrefis zero since k1,ris zero. To reduce the inverter loss from the uncoupled transmitter coil, the loop is designed to be at resonance. Hence, the circuit equation is written as by: jωL1′+1jωC1,p=0.(21) The total impedance Z of the parallel connection of by parallel capacitance C1,pand inductance L′1can be assumed as infinite. The equivalent circuit in the uncoupled condition can be redrawn as shown inFIG.5(b). Since the equivalent impedance Z=∞, the inverter current i1,sabecomes zero. Hence, the inverter losses due to uncoupled transmitter coil branches are negligible if the harmonic component of the inverter current is small enough due to the attenuation provided by the band pass filter. The equivalent circuits of the transmitter side when the primary coil L1is coupled and the primary tuning circuit is perfectly tuned (k1,r=kpeak) is shown inFIG.6.FIG.6includes circuit diagrams illustrating conversions of equivalent circuits of the WPT transmitter apparatus during a coupled condition, according to various embodiments.FIG.6(a)is a simplified equivalent circuit of the transmitter side converted fromFIG.4. Using Norton's theorem, the voltage source is converted to the equivalent current source and the equivalent circuitFIG.6(a)can be converted toFIG.6(b). The equivalent current source iinis represented by: iin=jωC′1,savin(22) Using Thevenin's theorem, the equivalent current source is converted to the equivalent voltage source andFIG.6(b)can be converted toFIG.6(c). The equivalent input voltage vinis represented by: vin′=C1,sa′C1,sa′+C1,pvin=vinn1(23) The following equation is satisfied since the equivalent circuit is in the fully resonated condition. 1jω(C1,p+C1,sa′)+jωL1′-jXref=0.(24) From the final equivalent circuit inFIG.6(d), We can see that v′incan be decreased or increased by n1to achieve proper voltage for the reflected resistance Rref. From equations (12), (21), and (24), C′1,sa, C1,sb, and C1,pare derived as: C1,sa′=1ω2kpeak2L1n1(n1-1)n2n3(25)C1,sb=1ω2L1(1-kpeak2n1n2n3),(26)C1,p=1ω2kpeak2n1n2n3.(27) From the equations above, loop currents i1,a, i1,b, ir,a, and ir,bcan be written as: i1,a=k1,r2(ωLrn3+jRloadn2)ωkpeak2L1n12n2n3{k1,r2Rloadn2+jωLr(kpeak2-k1,r2)n3}vin(28)i1,b=LrL1n1n2{k1,r2Rloadn2+jω(kpeak2-k1,r2)Lrn3}vin(29)ir,a=Lrk1,rL1n1{k1,r2Rloadn2+jω(kpeak2-k1,r2)Lrn3}vin(30)ir,b=k1,r(ωLrn3+jRloadn2)L1Lrn1{k1,r2Rloadn2+jω(kpeak2-k1,r2)Lrn3}vin.(31) The loop current in the fully coupled condition can be written as: i1,a❘"\[RightBracketingBar]"k1,r=kpeak=ωLrn3+jRloadn2ωL1kpeak2n12n22n3Rloadvin(32)i1,b❘"\[RightBracketingBar]"k1,r=kpeak=Lrkpeak2L1Rloadn1n22vin(33)ir,a❘"\[RightBracketingBar]"k1,r=kpeak=LrkpeakL1Rloadn1n2vin(34)ir,b❘"\[RightBracketingBar]"k1,r=kpeak=ωLrn3+jRloadn2ωkpeakL1LrRloadn1n2vin.(35) The inverter current i1,aand the transmitter current i1,bin uncoupled conditions can be calculated by substituting k1,r=0 to equations (30) and (31) as shown below. i1,a|k1,r=0=0(36)i1,b|k1,r=0=vinjωkpeak2L1n1n2n3.(37) Output equivalent resistance Rloadcan be represented as: Rload=Voutir,a(38) From equations (30) and (38), the equivalent load resistance Rloadcan be rewritten as: Rload=ωL1Lr(kpeak2-k1,r2)n1n3voutk1,rLrvin2-k1,r2L1n12n22vout2.(39) Finally, from equations (30) and (39), output power Poutcan be calculated by: Pout=ir,a·ir,a*·Rload2=k1,r2LrRloadvin22L1n12{k1,r4Rload2n22+ω2(kpeak2-k1,r2)2Lr2n32).(40) The output power in the fully coupled condition can be written as: Pout|k1,r=kpeak=Lrvin22kpeak2L1Rloadn12n22.(41) Using the equation of i1,band Pout, the transmitter current gain and output power can be designed simultaneously. Also, system efficiency can be estimated and designed by the equations of the loop current. By applying n1=n3=1, the derived equations can be used for the conventional circuit as well. In some embodiments, n1is in the range of 0 to 0.9 or greater than 1.1, which provides separation from the conventional circuit ofFIG.2. In other embodiments, n1is in the range of 0 to 0.8 or greater than 1.2 to provide even more separation and advantages. In other embodiments, n3is greater than 1.1. In other embodiments, n3is greater than 1.2 to provide more separation and greater advantages over the conventional circuit ofFIG.2. B. Comparison of the Pareto Fronts of the Proposed and Conventional Reflexive Field Containment Circuit To compare between the conventional and the proposed circuit designs, design points are plotted on the surface of coil efficiency versus output power Poutas shown inFIG.7.FIG.7is a diagram illustrating Pareto fronts of the proposed circuit design and the conventional circuit showing efficiency versus output power Pout, according to various embodiments. Poutis calculated by equation (40). Efficiency is calculated by equations (28), (29), (30), and (31). As the fixed design requirements, the following values are used for both designs: L1=L2=18.42 microhenries (“μH”), Lr=43.85 μH, k1,r=0˜0.120, kpeak=0.124˜0.130, QL=400, QC=800. The low voltage (50 volts (“V”)) was used for input and output voltage to facilitate the experiment. In the proposed reflexive field containment circuit design plots, n1, n2, and n3are randomly selected from 0<n1<1, 1<n2<10, and 1<n3<10. In the conventional reflexive field containment circuit design plots, n1, n2, and n3are randomly selected from n1=1, 1<n2<10, and n3=1. The two lines show the Pareto fronts of the proposed and conventional circuits. Because the conventional circuit needs to design its function by only n2, the maximum output power is much lower than the proposed circuit. From the graph, we can see that the proposed circuit has an advantage in the high output power area over approximately 1.6 kW in this design requirement case. III. PROTOTYPE DESIGN To show the advantage of the proposed converter over the conventional reflexive field containment circuit, both the designs are simulated under the same operating conditions. TABLE IDesign specifications for the proposed circuitParameterVariableValueInput voltageVdc50VOutput voltageVbat50VAir gapzgap250mmSwitching frequencyfsw85kHzCoupling factor between L1and Lrk1,r0.0~0.12Coupling factor between L1and L2k1,3−0.04Transmitter coil inductanceL1& L218.42μHReceiver coil inductanceLr43.85μHBandpass filter inductorLf5.05μHBandpass filter capacitorCf0.71μCOutput DC inductorLdc10.33μHParasitic inductance of wiresLpara,wire0.10μHParasitic inductance of capacitorsLpara,C0.10μHQuality factor of wireless coils andQL400inductorsQuality factor of capacitorsQC800Number of turns of the transmitterNL1& LL23coilsNumber of turns of the receiver coilNLr5 The design requirements are shown in TABLE I. The input voltage Vdcand output voltage Vbatare set at 50 V. A frequency of 85 kHz is selected as the transmission frequency fswfor the prototype designed to follow the Society of Automotive Engineers (“SAE”) standard. The coupling factor between the transmitter coil and the receiver coil k1,rvaries from 0 to 0.12, according to the position of the receiver coil due to longitudinal misalignment. The range of coupling factor k1,rwas extracted from Maxwell-simulations. The quality factors of coils and capacitors QLand QCare defined as: QL=ωLRLandQc=1ωCRC(42) where RLand RCare the equivalent series resistance of L and C respectively. The parasitic inductance of wires between each components is defined as Lpara,wire, and the parasitic inductance of capacitor banks is defined as Lpara,C. The designed parameters of the proposed and the conventional circuit are shown in TABLE II. Circuits were designed such that the amplitude of the uncoupled transmitter current IL1,uncoupledis 37 A in both the cases. n2is set to the same value (n2=8.93) between the two circuits to compare in the same design condition. n1and n3are set to 1 in the conventional circuit since the conventional circuit does not have C1,sa, L1,sa, and Cr,sa. TABLE IIDesign conditions for the proposed and conventional circuitsParameterProposedConventionaln11.281.00n28.938.93n31.461.00Series charging inductor L1,sa1.14μH—Series charging capacitor C1,sa1.60μH—Series charging capacitor C2,sa239μF236μFParallel charging capacitor C1,p1.02μF0.99μFSeries charging capacitor Cr,sa1.54μF—Series charging capacitor Cr,sa90μF90μFParallel charging capacitor Cr,p711μF711μF FIG.8illustrates circuit simulation results for the coupled condition and the uncoupled condition, according to various embodiments. LTspice simulation results of the proposed circuit are shown inFIG.8. LTspice® is a circuit simulation program.FIG.8(a)shows waveforms in a coupled condition (k1,r=kpeak). The transmitter current becomes maximum, and the amplitude is 96 amperes (“A”). As the inverter current inn is lagging the inverter voltage vin, the inverter current iinmaintains a soft-switching condition. Output power at the coupled condition is 2,022 W.FIG.8(b)shows waveforms in an uncoupled condition (k1,r=0). The amplitude of the transmitter current iL1is minimum and its values is 37 A. The inverter current iinis close to zero since the impedance of the compensation circuit from the inverter side can be assumed as infinite in the uncoupled condition. FIG.9illustrates circuit simulation results comparing current amplitude in the WPT transmission pad for the proposed and conventional reflexive field containment circuits, according to various embodiments. Sweep results of current amplitude IL1with respect to coupling factor k1,rfrom 0 to 0.12 are shown inFIG.9. The line with the diamond is the proposed circuit and the solid line is the conventional circuit. In the uncoupled condition (k1,r=0), the current amplitudes of both circuit are the same (IL1,uncoupled=37 A). In the coupled condition (k1,r=kpeak=0.12), current amplitude of the proposed one is 53% higher than the conventional one. FIG.10illustrates circuit simulation results comparing power output for the proposed and conventional reflexive field containment circuits, according to various embodiments. Sweep results of output power Poutwith respect to coupling factor k1,rfrom 0 to 0.12 are shown inFIG.10. In the coupled condition (k1,r=kpeak), the output power of the proposed solution is 102% higher than the conventional case. IV. EXPERIMENTAL VALIDATION An experiment was conducted to validate the design of the proposed circuit ofFIG.3A. A prototype of the proposed circuit was constructed with the coil parameters and the compensation parameters in TABLE I and TABLE II. An aluminum backplate of 750 mm×850 mm used for shielding is placed in a bottom layer, and a ferrite plate of 650 mm×850 mm is placed in a middle layer and centered on the aluminum plate. A transmitter coil embedded in a coil former is placed on a top layer. The horizontal spacing between the transmitter coils is kept small (45 mm) to mitigate the decrease in the output power in the region between the coils due to lower coupling. The receiver coil structure is similar to the transmitter coil, but an aluminum plate of the receiver is 725 mm×725 mm and a ferrite plate is 675 mm×675 mm. The ferrite plate dimensions are larger than the winding to increase the coupling, and the aluminum plate dimensions are larger than the ferrite plate to decrease the stray field. The thickness of the ferrite plates is 5 mm and that of the aluminum plates is 2 mm. The transmitter plates are separated by the receiver plate by 250 mm. The coils are 7 mm diameter Litz wires. Coil formers are made of high-density polyethylene (HDPE) sheets and the Litz wires are embedded into them. The prototype consists of two transmitter coils connected to compensation circuits, an inverter, a receiver coil, and a diode rectifier. To create a similar environment that replicates the intended application, adjacent coils are placed next to the transmitter coil L1and L2, respectively. This simulates the application of a DWPT system on the road. Magnetic stray field are measured at the observation point shown inFIG.14(a)using a field analyzer (model EHP-200 A/AC). The output power and transmitter current are measured as the receiver coil is moved from the center of the transmitter coil L1to the center of the transmitter coil L2in the longitudinal direction. FIG.11is a circuit diagram illustrating an experimental setup for the proposed reflexive field containment circuit topology, according to various embodiments. The diagram of the test setup with power feedback at the dc link is shown inFIG.11. The series compensation inductor L1,sais added in series at C1,sato cancel the effect of the parasitic inductance along the transmitter lines. In a practical system, these individual transmitter coils may be several meters away and each line to connect each transmitter coil and inverter has different lengths of wires. Then the inductance of the lines connecting to the resonators can significantly detune and unbalance the system. The added series inductors are utilized to adjust and compensate the unbalance of inductance. The power feedback via a dc wire allows circulating the transferred power within the system, instead of dissipating the power in a resistive load. While the transferred power is circulated, total losses are drawn from the external dc supply. Therefore, the DC current Ilossand the dc supply voltage Vdccan be measured to calculate the total power losses. The transferred power is calculated using the measured feedback current Ifb. All wireless coils and inductors were made from 2325-strand American Wire Gauge (“AWG”) 38 Litz-wire. Because of the small core loss and the large saturation flux density, Manganese-Zinc (“MnZn”) ferrite core (material PC95) by TDK® was used for the magnetic material of the wireless coils and inductors. A general-purpose full-bridge inverter is used on the primary side to provide the ac excitation. It contains two silicon carbide (“SiC”) half-bridge MOSFET module (model number CAS325M12HM2) with a rating voltage of 1.2 kV. The same SiC MOSFET modules are used as the diode rectifier as well. FIG.12illustrates experimental waveforms in the coupled condition and uncoupled condition, according to various embodiments. The voltage of the inverter vinand the current of the transmitter coil iL1are shown inFIG.12.FIG.12(a)shows the waveforms when the receiver coil is at the center of the transmitter coil L1. The measured amplitude of the current is 92 A and the output power is 1,952 W.FIG.12(b)shows the waveforms in uncoupled conditions. The output power is 0 W, and the amplitude of the current is 37 A. Therefore, the amplitude of the transmitter current in the coupled case is 2.5 times that of the uncoupled case. FIG.13illustrates a comparison of simulated results and experimental results for output power as receiver position changes from the center of a first WPT transmission pad to the center of a second WPT transmission pad, according to various embodiments. To verify the reflexive field containment capability of the system, the transmitter current and output power are measured as the receiver coil moves along the track.FIG.13shows the measured output power and DC-DC efficiency of the proposed circuit as the receiver coil moves with respect to the transmitter coils.FIG.13(a)shows the measured output power versus receiver position yr. At yr=0 mm, the measured output power matches well with the simulation value, which is calculated by the LTspice simulation described above. However, the measured output power at yr=895 mm is 14% less than the measured value at yr=0 mm because of an unbalance in the length of wires and compensation circuit between the inverter and transmitter coils.FIG.13(b)shows the measured DC-DC efficiency of the proposed circuit versus receiver position yr. The measured efficiencies is 74.9% at yr=0 mm when output power is 1,952 W and matches well with the simulation values along with all ranges of the receiver position. FIG.14illustrates a comparison of simulated results and experimental results for WPT transmission pad current for the first WPT transmission pad and the second WPT transmission pad as receiver position changes from the center of the first WPT transmission pad to the center of the second WPT transmission pad, according to various embodiments. The measured amplitude of the transmitter current at different receiver positions is shown inFIGS.14(a) and (b). As seen fromFIG.13andFIG.14, the experimental results match with the simulation results. FIG.15illustrates experimental results for WPT transmission pad current for the first WPT transmission pad and the second WPT transmission pad as receiver position changes from the center of the first WPT transmission pad to the center of the second WPT transmission pad for different alignment conditions, according to various embodiments. To verify the tolerance of the proposed circuit to misalignment in the lateral direction, transmitter current and output power have been measured with 100 mm misalignment in the lateral direction (xr=−100 mm).FIG.15shows the measured transmitter coil current with 100 mm misalignment.FIG.15(a)shows the current amplitude of the transmitter coil L1with respect to the receiver position at 100 mm misalignment. At yr=0 mm, the amplitude is 72 A. The current gain of transmitter coil L1is reduced by 22%.FIG.15(b)shows the current amplitude of transmitter coil L2with respect to receiver position at 100 mm misalignment. In the same way, at yr=0 mm, the amplitude is 64 A. The current gain of transmitter coil L1is reduced by 28%. FIG.16illustrates experimental results for output power Poutas receiver position changes from the center of the first WPT transmission pad to the center of the second WPT transmission pad for different alignment conditions, according to various embodiments. The output power versus the receiver position at 100 mm misalignment are shown inFIG.16. At yr=0 mm, the output power is 1082 W. Compared to the aligned case, the output power is decreased by 45%. To improve the tolerance to misalignment, larger ferrite plates are required for the transmitter and the receiver coils. FIG.17is a diagram illustrating measured magnetic field at the uncoupled condition for the conventional constant current topology and the proposed reflexive field containment topology, according to various embodiments. The measured magnetic field of the proposed circuit and the constant current circuit topology are shown inFIG.17. In the measurement, a double-sided LCC compensation circuit ofFIG.3Bin an uncoupled condition was used. The amplitude of the transmitter current is 92 A with the constant current circuit topology since the transmitter current is constant in both the coupled and uncoupled conditions. The measured maximum stray field of the constant current circuit is 13.3 μT (0-peak) at 85 kHz. On the other hand, the amplitude of the transmitter current created by the proposed circuit is 37 A in the uncoupled condition since the proposed circuit creates maximum current (=92 A) in only the coupled condition. The comparison of the measured and simulated results of the stray magnetic field in the uncoupled condition are shown in TABLE III. The experimental results and simulation results match well with a maximum error is 13.0%. From the results, the validity of the simulation results are shown. TABLE IIIComparison of the measured and simulation results of the straymagnetic field in the uncoupled conditionConventional constantDescriptionProposed circuitcurrent circuitExperiment5.4 μT (0-peak)13.3 μT (0-peak)Simulation4.7 μT (0-peak)12.2 μT (0-peak)Error−13%−8.3% Using the LTspice simulator described in above, the power loss in each component can be estimated, as shown inFIG.18. The all parameters used in the simulation are the same as the values listed in TABLE I. The transmitter coil L1and the receiver coil Lrconsume the highest power of all the components because the coil pads are not optimized for the proposed circuit. The system efficiency can be improved by using wider diameter Litz wires for the low voltage and high current system. Also, if the input voltage and output voltage are changed from 50 V to 400 V, which is the most common input and output dc voltage in vehicle applications, the system efficiency will improve as the low current and high voltage system can decrease conduction losses. If the system is designed for 50 kW, 400 V system with the same current gain of 2.5, the expected dc-dc efficiency is around 88% to 90% according to our simulation results. V. CONCLUSION As described herein, a reflexive field containment dynamic wireless power transfer (“DWPT”) system is proposed (e.g.,FIGS.3A-3C) that utilizes a reflected impedance to allow a single inverter to drive multiple transmitter coils. The validity of the proposed circuit has been demonstrated through circuit simulation and experimental results. The reflexive field containment approach can change the amplitude of the current in the transmitter coil automatically utilizing the reflected impedance. Hence, this approach can reduce the number of inverters and receiver-position sensors. The proposed circuit topology can achieve a higher output power and higher current gain of the transmitter coil compared to the conventional circuit. The proposed circuit and the conventional circuit have been designed, and the simulation result shows that the proposed circuit can increase the amplitude of the transmitter current by 53%, and the output power by 102% compared to the conventional circuit. A 2.0 kW prototype was constructed to validate the design of the proposed circuit. The experimental results show that the prototype matches well with the simulation results and that the circuit can amplify the transmitter current coil 2.5 times higher in the coupled condition than that of the uncoupled condition. The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. | 48,553 |
11862994 | While the following detailed description will be given with respect to certain illustrative embodiments, it should be understood that the drawings are not necessarily to scale and the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In addition, in certain instances, details which are not necessary for an understanding of the disclosed subject matter or which render other details too difficult to perceive may have been omitted. It should therefore be understood that this disclosure is not limited to the particular embodiments disclosed and illustrated herein, but rather to a fair reading of the entire disclosure and claims, as well as any equivalents thereto. Additional, different, or fewer components and methods may be included in the systems and methods. DETAILED DESCRIPTION In the following description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. Referring now to the drawings and with specific reference toFIG.1, a wireless power transfer system10is illustrated. The wireless power transfer system10provides for the wireless transmission of electrical signals, such as, but not limited to, electrical energy, electrical power, electrical power signals, electromagnetic energy, and electronically transmittable data (“electronic data”). As used herein, the term “electrical power signal” refers to an electrical signal transmitted specifically to provide meaningful electrical energy for charging and/or directly powering a load, whereas the term “electronic data signal” refers to an electrical signal that is utilized to convey data across a medium. The wireless power transfer system10provides for the wireless transmission of electrical signals via near field magnetic coupling. As shown in the embodiment ofFIG.1, the wireless power transfer system10includes one or more wireless transmission systems20and one or more wireless receiver systems30. A wireless receiver system30is configured to receive electrical signals from, at least, a wireless transmission system20. As illustrated, the wireless transmission system(s)20and wireless receiver system(s)30may be configured to transmit electrical signals across, at least, a separation distance or gap17. A separation distance or gap, such as the gap17, in the context of a wireless power transfer system, such as the system10, does not include a physical connection, such as a wired connection. There may be intermediary objects located in a separation distance or gap, such as, but not limited to, air, a counter top, a casing for an electronic device, a plastic filament, an insulator, a mechanical wall, among other things; however, there is no physical, electrical connection at such a separation distance or gap. Thus, the combination of two or more wireless transmission systems20and wireless receiver system30create an electrical connection without the need for a physical connection. As used herein, the term “electrical connection” refers to any facilitation of a transfer of an electrical current, voltage, and/or power from a first location, device, component, and/or source to a second location, device, component, and/or destination. An “electrical connection” may be a physical connection, such as, but not limited to, a wire, a trace, a via, among other physical electrical connections, connecting a first location, device, component, and/or source to a second location, device, component, and/or destination. Additionally or alternatively, an “electrical connection” may be a wireless power and/or data transfer, such as, but not limited to, magnetic, electromagnetic, resonant, and/or inductive field, among other wireless power and/or data transfers, connecting a first location, device, component, and/or source to a second location, device, component, and/or destination. Further, whileFIGS.1-2may depict wireless power signals and wireless data signals transferring only from one antenna (e.g., a transmission antenna21) to another antenna (e.g., a receiver antenna31and/or a transmission antenna21), it is certainly possible that a transmitting antenna21may transfer electrical signals and/or couple with one or more other antennas and transfer, at least in part, components of the output signals or magnetic fields of the transmitting antenna21. Such transmission may include secondary and/or stray coupling or signal transfer to multiple antennas of the system10. In some cases, the gap17may also be referenced as a “Z-Distance,” because, if one considers an antenna21,31each to be disposed substantially along respective common X-Y planes, then the distance separating the antennas21,31is the gap in a “Z” or “depth” direction. However, flexible and/or non-planar coils are certainly contemplated by embodiments of the present disclosure and, thus, it is contemplated that the gap17may not be uniform, across an envelope of connection distances between the antennas21,31. It is contemplated that various tunings, configurations, and/or other parameters may alter the possible maximum distance of the gap17, such that electrical transmission from the wireless transmission system20to the wireless receiver system30remains possible. The wireless power transfer system10operates when the wireless transmission system20and the wireless receiver system30are coupled. As used herein, the terms “couples,” “coupled,” and “coupling” generally refer to magnetic field coupling, which occurs when a transmitter and/or any components thereof and a receiver and/or any components thereof are coupled to each other through a magnetic field. Such coupling may include coupling, represented by a coupling coefficient (k), that is at least sufficient for an induced electrical power signal, from a transmitter, to be harnessed by a receiver. Coupling of the wireless transmission system20and the wireless receiver system30, in the system10, may be represented by a resonant coupling coefficient of the system10and, for the purposes of wireless power transfer, the coupling coefficient for the system10may be in the range of about 0.01 and 0.9. As illustrated, at least one wireless transmission system20is associated with an input power source12. The input power source12may be operatively associated with a host device, which may be any electrically operated device, circuit board, electronic assembly, dedicated charging device, or any other contemplated electronic device. Example host devices, with which the wireless transmission system20may be associated therewith, include, but are not limited to including, a device that includes an integrated circuit, a portable computing device, storage medium for electronic devices, charging apparatus for one or multiple electronic devices, dedicated electrical charging devices, among other contemplated electronic devices. The input power source12may be or may include one or more electrical storage devices, such as an electrochemical cell, a battery pack, and/or a capacitor, among other storage devices. Additionally or alternatively, the input power source12may be any electrical input source (e.g., any alternating current (AC) or direct current (DC) delivery port) and may include connection apparatus from said electrical input source to the wireless transmission system20(e.g., transformers, regulators, conductive conduits, traces, wires, or equipment, goods, computer, camera, mobile phone, and/or other electrical device connection ports and/or adaptors, such as but not limited to USB ports and/or adaptors, among other contemplated electrical components). Electrical energy received by the wireless transmission system(s)20is then used for at least two purposes: to provide electrical power to internal components of the wireless transmission system20and to provide electrical power to the transmission antenna21. The transmission antenna21is configured to wirelessly transmit the electrical signals conditioned and modified for wireless transmission by the wireless transmission system20via near-field magnetic coupling (NFMC). Near-field magnetic coupling enables the transfer of signals wirelessly through magnetic induction between the transmission antenna21and one or more of receiving antenna31of, or associated with, the wireless receiver system30, another transmission antenna21, or combinations thereof. Near-field magnetic coupling may be and/or be referred to as “inductive coupling,” which, as used herein, is a wireless power transmission technique that utilizes an alternating electromagnetic field to transfer electrical energy between two antennas. Such inductive coupling is the near field wireless transmission of magnetic energy between two magnetically coupled coils that are tuned to resonate at a similar frequency. Accordingly, such near-field magnetic coupling may enable efficient wireless power transmission via resonant transmission of confined magnetic fields. Further, such near-field magnetic coupling may provide connection via “mutual inductance,” which, as defined herein is the production of an electromotive force in a circuit by a change in current in a second circuit magnetically coupled to the first. In one or more embodiments, the inductor coils of either the transmission antenna21or the receiver antenna31are strategically positioned to facilitate reception and/or transmission of wirelessly transferred electrical signals through near field magnetic induction. Antenna operating frequencies may comprise relatively high operating frequency ranges, examples of which may include, but are not limited to, 6.78 MHz (e.g., in accordance with the Rezence and/or Airfuel interface standard and/or any other proprietary interface standard operating at a frequency of 6.78 MHz), 13.56 MHz (e.g., in accordance with the NFC standard, defined by ISO/IEC standard 18092), 27 MHz, and/or an operating frequency of another proprietary operating mode. The operating frequencies of the antennas21,31may be operating frequencies designated by the International Telecommunications Union (ITU) in the Industrial, Scientific, and Medical (ISM) frequency bands, including not limited to 6.78 MHz, 13.56 MHz, and 27 MHz, which are designated for use in wireless power transfer. The transmitting antenna and the receiving antenna of the present disclosure may be configured to transmit and/or receive electrical power having a magnitude that ranges from about 10 milliwatts (mW) to about 500 watts (W). In one or more embodiments the inductor coil of the transmitting antenna21is configured to resonate at a transmitting antenna resonant frequency or within a transmitting antenna resonant frequency band. As known to those skilled in the art, a “resonant frequency” or “resonant frequency band” refers a frequency or frequencies wherein amplitude response of the antenna is at a relative maximum, or, additionally or alternatively, the frequency or frequency band where the capacitive reactance has a magnitude substantially similar to the magnitude of the inductive reactance. In one or more embodiments, the transmitting antenna resonant frequency is at a high frequency, as known to those in the art of wireless power transfer. The wireless receiver system30may be associated with at least one electronic device14, wherein the electronic device14may be any device that requires electrical power for any function and/or for power storage (e.g., via a battery and/or capacitor). Additionally, the electronic device14may be any device capable of receipt of electronically transmissible data. For example, the device may be, but is not limited to being, a handheld computing device, a mobile device, a portable appliance, a computer peripheral, an integrated circuit, an identifiable tag, a kitchen utility device, an electronic tool, an electric vehicle, a game console, a robotic device, a wearable electronic device (e.g., an electronic watch, electronically modified glasses, altered-reality (AR) glasses, virtual reality (VR) glasses, among other things), a portable scanning device, a portable identifying device, a sporting good, an embedded sensor, an Internet of Things (IoT) sensor, IoT enabled clothing, IoT enabled recreational equipment, industrial equipment, medical equipment, a medical device a tablet computing device, a portable control device, a remote controller for an electronic device, a gaming controller, among other things. For the purposes of illustrating the features and characteristics of the disclosed embodiments, arrow-ended lines are utilized to illustrate transferrable and/or communicative signals and various patterns are used to illustrate electrical signals that are intended for power transmission and electrical signals that are intended for the transmission of data and/or control instructions. Solid lines indicate signal transmission of electrical energy over a physical and/or wireless power transfer, in the form of power signals that are, ultimately, utilized in wireless power transmission from the wireless transmission system20to the wireless receiver system30. Further, dotted lines are utilized to illustrate electronically transmittable data signals, which ultimately may be wirelessly transmitted from the wireless transmission system20to the wireless receiver system30. While the systems and methods herein illustrate the transmission of wirelessly transmitted energy, wireless power signals, wirelessly transmitted power, wirelessly transmitted electromagnetic energy, and/or electronically transmittable data, it is certainly contemplated that the systems, methods, and apparatus disclosed herein may be utilized in the transmission of only one signal, various combinations of two signals, or more than two signals and, further, it is contemplated that the systems, method, and apparatus disclosed herein may be utilized for wireless transmission of other electrical signals in addition to or uniquely in combination with one or more of the above mentioned signals. In some examples, the signal paths of solid or dotted lines may represent a functional signal path, whereas, in practical application, the actual signal is routed through additional components en route to its indicated destination. For example, it may be indicated that a data signal routes from a communications apparatus to another communications apparatus; however, in practical application, the data signal may be routed through an amplifier, then through a transmission antenna, to a receiver antenna, where, on the receiver end, the data signal is decoded by a respective communications device of the receiver. Turning now toFIG.2, the wireless power transfer system10is illustrated as a block diagram including example sub-systems of both the wireless transmission systems20and the wireless receiver systems30. The wireless transmission systems20may include, at least, a power conditioning system40, a transmission control system26, a demodulation circuit70, a transmission tuning system24, and the transmission antenna21. A first portion of the electrical energy input from the input power source12may be configured to electrically power components of the wireless transmission system20such as, but not limited to, the transmission control system26. A second portion of the electrical energy input from the input power source12is conditioned and/or modified for wireless power transmission, to the wireless receiver system30, via the transmission antenna21. Accordingly, the second portion of the input energy is modified and/or conditioned by the power conditioning system40. While not illustrated, it is certainly contemplated that one or both of the first and second portions of the input electrical energy may be modified, conditioned, altered, and/or otherwise changed prior to receipt by the power conditioning system40and/or transmission control system26, by further contemplated subsystems (e.g., a voltage regulator, a current regulator, switching systems, fault systems, safety regulators, among other things). Referring now toFIG.3, with continued reference toFIGS.1and2, subcomponents and/or systems of the transmission control system26are illustrated. The transmission control system26may include a sensing system50, a transmission controller28, a communications system29, a driver48, and a memory27. The transmission controller28may be any electronic controller or computing system that includes, at least, a processor which performs operations, executes control algorithms, stores data, retrieves data, gathers data, controls and/or provides communication with other components and/or subsystems associated with the wireless transmission system and/or performs any other computing or controlling task desired. The transmission controller28may be a single controller or may include more than one controller disposed to control various functions and/or features of the wireless transmission system20. Functionality of the transmission controller28may be implemented in hardware and/or software and may rely on one or more data maps relating to the operation of the wireless transmission system20. To that end, the transmission controller28may be operatively associated with the memory27. The memory may include one or more of internal memory, external memory, and/or remote memory (e.g., a database and/or server operatively connected to the transmission controller28via a network, such as, but not limited to, the Internet). The internal memory and/or external memory may include, but are not limited to including, one or more of a read only memory (ROM), including programmable read-only memory (PROM), erasable programmable read-only memory (EPROM or sometimes but rarely labelled EROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDR SDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data rate synchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5, a flash memory, a portable memory, and the like. Such memory media are examples of nontransitory machine readable and/or computer readable memory media. While particular elements of the transmission control system26are illustrated as independent components and/or circuits (e.g., the driver48, the memory27, the communications system29, the sensing system50, among other contemplated elements) of the transmission control system26, such components may be integrated with the transmission controller28. In some examples, the transmission controller28may be an integrated circuit configured to include functional elements of one or both of the transmission controller28and the wireless transmission system20, generally. As illustrated, the transmission controller28is in operative association, for the purposes of data transmission, receipt, and/or communication, with, at least, the memory27, the communications system29, the power conditioning system40, the driver48, and the sensing system50. The driver48may be implemented to control, at least in part, the operation of the power conditioning system40. In some examples, the driver48may receive instructions from the transmission controller28to generate and/or output a generated pulse width modulation (PWM) signal to the power conditioning system40. In some such examples, the PWM signal may be configured to drive the power conditioning system40to output electrical power as an alternating current signal, having an operating frequency defined by the PWM signal. In some examples, PWM signal may be configured to generate a duty cycle for the AC power signal output by the power conditioning system40. In some such examples, the duty cycle may be configured to be about 50% of a given period of the AC power signal. The sensing system may include one or more sensors, wherein each sensor may be operatively associated with one or more components of the wireless transmission system20and configured to provide information and/or data. The term “sensor” is used in its broadest interpretation to define one or more components operatively associated with the wireless transmission system20that operate to sense functions, conditions, electrical characteristics, operations, and/or operating characteristics of one or more of the wireless transmission system20, the wireless receiving system30, the input power source12, the host device11, the transmission antenna21, the receiver antenna31, along with any other components and/or subcomponents thereof. As illustrated in the embodiment ofFIG.4, the sensing system50may include, but is not limited to including, a thermal sensing system52, an object sensing system54, a receiver sensing system56, a current sensor57, and/or any other sensor(s)58. Within these systems, there may exist even more specific optional additional or alternative sensing systems addressing particular sensing aspects required by an application, such as, but not limited to: a condition-based maintenance sensing system, a performance optimization sensing system, a state-of-charge sensing system, a temperature management sensing system, a component heating sensing system, an IoT sensing system, an energy and/or power management sensing system, an impact detection sensing system, an electrical status sensing system, a speed detection sensing system, a device health sensing system, among others. The object sensing system54, may be a foreign object detection (FOD) system. Each of the thermal sensing system52, the object sensing system54, the receiver sensing system56, the current sensor57and/or the other sensor(s)58, including the optional additional or alternative systems, are operatively and/or communicatively connected to the transmission controller28. The thermal sensing system52is configured to monitor ambient and/or component temperatures within the wireless transmission system20or other elements nearby the wireless transmission system20. The thermal sensing system52may be configured to detect a temperature within the wireless transmission system20and, if the detected temperature exceeds a threshold temperature, the transmission controller28prevents the wireless transmission system20from operating. Such a threshold temperature may be configured for safety considerations, operational considerations, efficiency considerations, and/or any combinations thereof. In a non-limiting example, if, via input from the thermal sensing system52, the transmission controller28determines that the temperature within the wireless transmission system20has increased from an acceptable operating temperature to an undesired operating temperature (e.g., in a non-limiting example, the internal temperature increasing from about 20° Celsius (C) to about 50° C., the transmission controller28prevents the operation of the wireless transmission system20and/or reduces levels of power output from the wireless transmission system20. In some non-limiting examples, the thermal sensing system52may include one or more of a thermocouple, a thermistor, a negative temperature coefficient (NTC) resistor, a resistance temperature detector (RTD), and/or any combinations thereof. As depicted inFIG.4, the transmission sensing system50may include the object sensing system54. The object sensing system54may be configured to detect one or more of the wireless receiver system30and/or the receiver antenna31, thus indicating to the transmission controller28that the receiver system30is proximate to the wireless transmission system20. Additionally or alternatively, the object sensing system54may be configured to detect presence of unwanted objects in contact with or proximate to the wireless transmission system20. In some examples, the object sensing system54is configured to detect the presence of an undesired object. In some such examples, if the transmission controller28, via information provided by the object sensing system54, detects the presence of an undesired object, then the transmission controller28prevents or otherwise modifies operation of the wireless transmission system20. In some examples, the object sensing system54utilizes an impedance change detection scheme, in which the transmission controller28analyzes a change in electrical impedance observed by the transmission antenna20against a known, acceptable electrical impedance value or range of electrical impedance values. Additionally or alternatively, the object sensing system54may utilize a quality factor (Q) change detection scheme, in which the transmission controller28analyzes a change from a known quality factor value or range of quality factor values of the object being detected, such as the receiver antenna31. The “quality factor” or “Q” of an inductor can be defined as (frequency (Hz)×inductance (H))/resistance (ohms), where frequency is the operational frequency of the circuit, inductance is the inductance output of the inductor and resistance is the combination of the radiative and reactive resistances that are internal to the inductor. “Quality factor,” as defined herein, is generally accepted as an index (figure of measure) that measures the efficiency of an apparatus like an antenna, a circuit, or a resonator. In some examples, the object sensing system54may include one or more of an optical sensor, an electro-optical sensor, a Hall effect sensor, a proximity sensor, and/or any combinations thereof. In some examples, the quality factor measurements, described above, may be performed when the wireless power transfer system10is performing in band communications. The receiver sensing system56is any sensor, circuit, and/or combinations thereof configured to detect presence of any wireless receiving system that may be couplable with the wireless transmission system20. In some examples, the receiver sensing system56and the object sensing system54may be combined, may share components, and/or may be embodied by one or more common components. In some examples, if the presence of any such wireless receiving system is detected, wireless transmission of electrical energy, electrical power, electromagnetic energy, and/or data by the wireless transmission system20to said wireless receiving system is enabled. In some examples, if the presence of a wireless receiver system is not detected, continued wireless transmission of electrical energy, electrical power, electromagnetic energy, and/or data is prevented from occurring. Accordingly, the receiver sensing system56may include one or more sensors and/or may be operatively associated with one or more sensors that are configured to analyze electrical characteristics within an environment of or proximate to the wireless transmission system20and, based on the electrical characteristics, determine presence of a wireless receiver system30. The current sensor57may be any sensor configured to determine electrical information from an electrical signal, such as a voltage or a current, based on a current reading at the current sensor57. Components of an example current sensor57are further illustrated inFIG.5, which is a block diagram for the current sensor57. The current sensor57may include a transformer51, a rectifier53, and/or a low pass filter55, to process the AC wireless signals, transferred via coupling between the wireless receiver system(s)20and wireless transmission system(s)30, to determine or provide information to derive a current (ITx) or voltage (VTx) at the transmission antenna21. The transformer51may receive the AC wireless signals and either step up or step down the voltage of the AC wireless signal, such that it can properly be processed by the current sensor. The rectifier53may receive the transformed AC wireless signal and rectify the signal, such that any negative remaining in the transformed AC wireless signal are either eliminated or converted to opposite positive voltages, to generate a rectified AC wireless signal. The low pass filter55is configured to receive the rectified AC wireless signal and filter out AC components (e.g., the operating or carrier frequency of the AC wireless signal) of the rectified AC wireless signal, such that a DC voltage is output for the current (ITx) and/or voltage (VTx) at the transmission antenna21. FIG.6is a block diagram for a demodulation circuit70for the wireless transmission system(s)20, which is used by the wireless transmission system20to simplify or decode components of wireless data signals of an alternating current (AC) wireless signal, prior to transmission of the wireless data signal to the transmission controller28. The demodulation circuit includes, at least, a slope detector72and a comparator74. In some examples, the demodulation circuit70includes a set/reset (SR) latch76. In some examples, the demodulation circuit70may be an analog circuit comprised of one or more passive components (e.g., resistors, capacitors, inductors, diodes, among other passive components) and/or one or more active components (e.g., operational amplifiers, logic gates, among other active components). Alternatively, it is contemplated that the demodulation circuit70and some or all of its components may be implemented as an integrated circuit (IC). In either an analog circuit or IC, it is contemplated that the demodulation circuit may be external of the transmission controller28and is configured to provide information associated with wireless data signals transmitted from the wireless receiver system30to the wireless transmission system20. The demodulation circuit70is configured to receive electrical information (e.g., ITx, VTx) from at least one sensor (e.g., a sensor of the sensing system50), detect a change in such electrical information, determine if the change in the electrical information meets or exceeds one of a rise threshold or a fall threshold. If the change exceeds one of the rise threshold or the fall threshold, the demodulation circuit70generates an alert, and, outputs a plurality of data alerts. Such data alerts are received by the transmitter controller28and decoded by the transmitter controller28to determine the wireless data signals. In other words, the demodulation circuit70is configured to monitor the slope of an electrical signal (e.g., slope of a voltage at the power conditioning system32of a wireless receiver system30) and output an alert if said slope exceeds a maximum slope threshold or undershoots a minimum slope threshold. Such slope monitoring and/or slope detection by the communications system70is particularly useful when detecting or decoding an amplitude shift keying (ASK) signal that encodes the wireless data signals in-band of the wireless power signal at the operating frequency. In an ASK signal, the wireless data signals are encoded by damping the voltage of the magnetic field between the wireless transmission system20and the wireless receiver system30. Such damping and subsequent re-rising of the voltage in the field is performed based on an encoding scheme for the wireless data signals (e.g., binary coding, Manchester coding, pulse-width modulated coding, among other known or novel coding systems and methods). The receiver of the wireless data signals (e.g., the wireless transmission system20) must then detect rising and falling edges of the voltage of the field and decode said rising and falling edges to receive the wireless data signals. While in a theoretical, ideal scenario, an ASK signal will rise and fall instantaneously, with no slope between the high voltage and the low voltage for ASK modulation; however, in physical reality, there is some time that passes when the ASK signal transitions from the “high” voltage to the “low” voltage. Thus, the voltage or current signal sensed by the demodulation circuit70will have some, knowable slope or rate of change in voltage when transitioning from the high ASK voltage to the low ASK voltage. By configuring the demodulation circuit70to determine when said slope meets, overshoots and/or undershoots such rise and fall thresholds, known for the slope when operating in the system10, the demodulation circuit can accurately detect rising and falling edges of the ASK signal. Thus, a relatively inexpensive and/or simplified circuit may be utilized to, at least partially, decode ASK signals down to alerts for rising and falling instances. So long as the transmission controller28is programmed to understand the coding schema of the ASK modulation, the transmission controller28will expend far less computational resources than it would if it had to decode the leading and falling edges directly from an input current or voltage sense signal from the sensing system50. To that end, as the computational resources required by the transmission controller28to decode the wireless data signals are significantly decreased due to the inclusion of the demodulation circuit70, the demodulation circuit70may significantly reduce BOM of the wireless transmission system20, by allowing usage of cheaper, less computationally capable processor(s) for or with the transmission controller28. The demodulation circuit70may be particularly useful in reducing the computational burden for decoding data signals, at the transmitter controller28, when the ASK wireless data signals are encoded/decoded utilizing a pulse-width encoded ASK signals, in-band of the wireless power signals. A pulse-width encoded ASK signal refers to a signal wherein the data is encoded as a percentage of a period of a signal. For example, a two-bit pulse width encoded signal may encode a start bit as 20% of a period between high edges of the signal, encode “1” as 40% of a period between high edges of the signal, and encode “0” as 60% of a period between high edges of the signal, to generate a binary encoding format in the pulse width encoding scheme. Thus, as the pulse width encoding relies solely on monitoring rising and falling edges of the ASK signal, the periods between rising times need not be constant and the data signals may be asynchronous or “unclocked.” Examples of pulse width encoding and systems and methods to perform such pulse width encoding are explained in greater detail in U.S. patent application Ser. No. 16/735,342 titled “Systems and Methods for Wireless Power Transfer Including Pulse Width Encoded Data Communications,” to Michael Katz, which is commonly owned by the owner of the instant application and is hereby incorporated by reference. Turning now toFIG.7, with continued reference toFIG.6, an electrical schematic diagram for the demodulation circuit70is illustrated. Additionally, reference will be made toFIG.8, which is an exemplary timing diagram illustrating signal shape or waveform at various stages or sub-circuits of the demodulation circuit70. The input signal to the demodulation circuit70is illustrated inFIG.7as Plot A, showing rising and falling edges from a “high” voltage (VHigh) on the transmission antenna21to a “low” voltage (VLow) on the transmission antenna21. The voltage signal of Plot A may be derived from, for example, a current (ITx) sensed at the transmission antenna21by one or more sensors of the sensing system50. Such rises and falls from VHighto VLowmay be caused by load modulation, performed at the wireless receiver system(s)30, to modulate the wireless power signals to include the wireless data signals via ASK modulation. As illustrated, the voltage of Plot A does not cleanly rise and fall when the ASK modulation is performed; rather, a slope or slopes, indicating rate(s) of change, occur during the transitions from VHighto VLowand vice versa. As illustrated inFIG.7, the slope detector72includes a high pass filter71, an operation amplifier (OpAmp) OPSD, and an optional stabilizing circuit73. The high pass filter71is configured to monitor for higher frequency components of the AC wireless signals and may include, at least, a filter capacitor (CHF) and a filter resistor (RHF). The values for CHFand RHFare selected and/or tuned for a desired cutoff frequency for the high pass filter71. In some examples, the cutoff frequency for the high pass filter71may be selected as a value greater than or equal to about 1-2 kHz, to ensure adequately fast slope detection by the slope detector72, when the operating frequency of the system10is on the order of MHz (e.g., an operating frequency of about 6.78 MHz). In some examples, the high pass filter71is configured such that harmonic components of the detected slope are unfiltered. In view of the current sensor57ofFIG.5, the high pass filter71and the low pass filter55, in combination, may function as a bandpass filter for the demodulation circuit70. OPSDis any operational amplifier having an adequate bandwidth for proper signal response, for outputting the slope of VTx, but low enough to attenuate components of the signal that are based on the operating frequency and/or harmonics of the operating frequency. Additionally or alternatively, OPSDmay be selected to have a small input voltage range for VTx, such that OPSDmay avoid unnecessary error or clipping during large changes in voltage at VTx. Further, an input bias voltage (VBias) for OPSDmay be selected based on values that ensure OPSDwill not saturate under boundary conditions (e.g., steepest slopes, largest changes in VTx). It is to be noted, and is illustrated in Plot B ofFIG.8, that when no slope is detected, the output of the slope detector72will be VBias. As the passive components of the slope detector72will set the terminals and zeroes for a transfer function of the slope detector72, such passive components must be selected to ensure stability. To that end, if the desired and/or available components selected for CHFand RHFdo not adequately set the terminals and zeros for the transfer function, additional, optional stability capacitor(s) CST may be placed in parallel with RHFand stability resistor RST may be placed in the input path to OPSD. Output of the slope detector72(Plot B representing VSD) may approximate the following equation: VSD=-RHFCHFdVdt+VBias Thus, VSDwill approximate to VBias, when no change in voltage (slope) is detected, and VSDwill output the change in voltage (dV/dt), as scaled by the high pass filter71, when VTxrises and falls between the high voltage and the low voltage of the ASK modulation. The output of the slope detector72, as illustrated in Plot B, may be a pulse, showing slope of VTxrise and fall. VSDis output to the comparator circuit(s)74, which is configured to receive VSD, compare VSDto a rising rate of change for the voltage (VSUp) and a falling rate of change for the voltage (VSLo). If VSDexceeds or meets VSUp, then the comparator circuit will determine that the change in VTxmeets the rise threshold and indicates a rising edge in the ASK modulation. If VSDgoes below or meets VSLow, then the comparator circuit will determine that the change in VTxmeets the fall threshold and indicates a falling edge of the ASK modulation. It is to be noted that VSUpand VSLomay be selected to ensure a symmetrical triggering. In some examples, such as the comparator circuit74illustrated inFIG.6, the comparator circuit74may comprise a window comparator circuit. In such examples, the VSUpand VSLomay be set as a fraction of the power supply determined by resistor values of the comparator circuit74. In some such examples, resistor values in the comparator circuit may be configured such that VSup=Vin[RU2RU1+RU2]VSLo=Vin[RL2RL1+RL2]where Vin is a power supply determined by the comparator circuit74. When VSDexceeds the set limits for VSupor VSLo, the comparator circuit74triggers and pulls the output (VCout) low. Further, while the output of the comparator circuit74could be output to the transmission controller28and utilized to decode the wireless data signals by signaling the rising and falling edges of the ASK modulation, in some examples, the SR latch76may be included to add noise reduction and/or a filtering mechanism for the slope detector72. The SR latch76may be configured to latch the signal (Plot C) in a steady state to be read by the transmitter controller28, until a reset is performed. In some examples, the SR latch76may perform functions of latching the comparator signal and serve as an inverter to create an active high alert out signal. Accordingly, the SR latch76may be any SR latch known in the art configured to sequentially excite when the system detects a slope or other modulation excitation. As illustrated, the SR latch76may include NOR gates, wherein such NOR gates may be configured to have an adequate propagation delay for the signal. For example, the SR latch76may include two NOR gates (NORUp, NORLo), each NOR gate operatively associated with the upper voltage output78of the comparator74and the lower voltage output79of the comparator74. In some examples, such as those illustrated in Plot C, a reset of the SR latch76is triggered when the comparator circuit74outputs detection of VSUp(solid plot on Plot C) and a set of the SR latch76is triggered when the comparator circuit74outputs VSLo(dashed plot on Plot C). Thus, the reset of the SR latch76indicates a falling edge of the ASK modulation and the set of the SR latch76indicates a rising edge of the ASK modulation. Accordingly, as illustrated in Plot D, the rising and falling edges, indicated by the demodulation circuit70, are input to the transmission controller28as alerts, which are decoded to determine the received wireless data signal transmitted, via the ASK modulation, from the wireless receiver system(s)30. Referring now toFIG.9, and with continued reference toFIGS.1-4, a block diagram illustrating an embodiment of the power conditioning system40is illustrated. At the power conditioning system40, electrical power is received, generally, as a DC power source, via the input power source12itself or an intervening power converter, converting an AC source to a DC source (not shown). A voltage regulator46receives the electrical power from the input power source12and is configured to provide electrical power for transmission by the antenna21and provide electrical power for powering components of the wireless transmission system21. Accordingly, the voltage regulator46is configured to convert the received electrical power into at least two electrical power signals, each at a proper voltage for operation of the respective downstream components: a first electrical power signal to electrically power any components of the wireless transmission system20and a second portion conditioned and modified for wireless transmission to the wireless receiver system30. As illustrated inFIG.3, such a first portion is transmitted to, at least, the sensing system the transmission controller28, and the communications system29; however, the first portion is not limited to transmission to just these components and can be transmitted to any electrical components of the wireless transmission system20. The second portion of the electrical power is provided to an amplifier42of the power conditioning system40, which is configured to condition the electrical power for wireless transmission by the antenna21. The amplifier may function as an invertor, which receives an input DC power signal from the voltage regulator46and generates an AC as output, based, at least in part, on PWM input from the transmission control system26. The amplifier42may be or include, for example, a power stage invertor, such as a single field effect transistor (FET), a dual field effect transistor power stage invertor or a quadruple field effect transistor power stage invertor. The use of the amplifier42within the power conditioning system40and, in turn, the wireless transmission system20enables wireless transmission of electrical signals having much greater amplitudes than if transmitted without such an amplifier. For example, the addition of the amplifier42may enable the wireless transmission system20to transmit electrical energy as an electrical power signal having electrical power from about 10 mW to about 500 W. In some examples, the amplifier42may be or may include one or more class-E power amplifiers. Class-E power amplifiers are efficiently tuned switching power amplifiers designed for use at high frequencies (e.g., frequencies from about 1 MHz to about 1 GHz). Generally, a single-ended class-E amplifier employs a single-terminal switching element and a tuned reactive network between the switch and an output load (e.g., the antenna21). Class E amplifiers may achieve high efficiency at high frequencies by only operating the switching element at points of zero current (e.g., on-to-off switching) or zero voltage (off to on switching). Such switching characteristics may minimize power lost in the switch, even when the switching time of the device is long compared to the frequency of operation. However, the amplifier42is certainly not limited to being a class-E power amplifier and may be or may include one or more of a class D amplifier, a class EF amplifier, an H invertor amplifier, and/or a push-pull invertor, among other amplifiers that could be included as part of the amplifier42. Turning now toFIG.10and with continued reference to, at least,FIGS.1and2, the wireless receiver system30is illustrated in further detail. The wireless receiver system30is configured to receive, at least, electrical energy, electrical power, electromagnetic energy, and/or electrically transmittable data via near field magnetic coupling from the wireless transmission system20, via the transmission antenna21. As illustrated inFIG.9, the wireless receiver system30includes, at least, the receiver antenna31, a receiver tuning and filtering system34, a power conditioning system32, a receiver control system36, and a voltage isolation circuit70. The receiver tuning and filtering system34may be configured to substantially match the electrical impedance of the wireless transmission system20. In some examples, the receiver tuning and filtering system34may be configured to dynamically adjust and substantially match the electrical impedance of the receiver antenna31to a characteristic impedance of the power generator or the load at a driving frequency of the transmission antenna20. As illustrated, the power conditioning system32includes a rectifier33and a voltage regulator35. In some examples, the rectifier33is in electrical connection with the receiver tuning and filtering system34. The rectifier33is configured to modify the received electrical energy from an alternating current electrical energy signal to a direct current electrical energy signal. In some examples, the rectifier33is comprised of at least one diode. Some non-limiting example configurations for the rectifier33include, but are not limited to including, a full wave rectifier, including a center tapped full wave rectifier and a full wave rectifier with filter, a half wave rectifier, including a half wave rectifier with filter, a bridge rectifier, including a bridge rectifier with filter, a split supply rectifier, a single phase rectifier, a three phase rectifier, a voltage doubler, a synchronous voltage rectifier, a controlled rectifier, an uncontrolled rectifier, and a half controlled rectifier. As electronic devices may be sensitive to voltage, additional protection of the electronic device may be provided by clipper circuits or devices. In this respect, the rectifier33may further include a clipper circuit or a clipper device, which is a circuit or device that removes either the positive half (top half), the negative half (bottom half), or both the positive and the negative halves of an input AC signal. In other words, a clipper is a circuit or device that limits the positive amplitude, the negative amplitude, or both the positive and the negative amplitudes of the input AC signal. Some non-limiting examples of a voltage regulator35include, but are not limited to, including a series linear voltage regulator, a buck convertor, a low dropout (LDO) regulator, a shunt linear voltage regulator, a step up switching voltage regulator, a step down switching voltage regulator, an invertor voltage regulator, a Zener controlled transistor series voltage regulator, a charge pump regulator, and an emitter follower voltage regulator. The voltage regulator35may further include a voltage multiplier, which is as an electronic circuit or device that delivers an output voltage having an amplitude (peak value) that is two, three, or more times greater than the amplitude (peak value) of the input voltage. The voltage regulator35is in electrical connection with the rectifier33and configured to adjust the amplitude of the electrical voltage of the wirelessly received electrical energy signal, after conversion to AC by the rectifier33. In some examples, the voltage regulator35may an LDO linear voltage regulator; however, other voltage regulation circuits and/or systems are contemplated. As illustrated, the direct current electrical energy signal output by the voltage regulator35is received at the load16of the electronic device14. In some examples, a portion of the direct current electrical power signal may be utilized to power the receiver control system36and any components thereof; however, it is certainly possible that the receiver control system36, and any components thereof, may be powered and/or receive signals from the load16(e.g., when the load16is a battery and/or other power source) and/or other components of the electronic device14. The receiver control system36may include, but is not limited to including, a receiver controller38, a communications system39and a memory37. The receiver controller38may be any electronic controller or computing system that includes, at least, a processor which performs operations, executes control algorithms, stores data, retrieves data, gathers data, controls and/or provides communication with other components and/or subsystems associated with the wireless receiver system30. The receiver controller38may be a single controller or may include more than one controller disposed to control various functions and/or features of the wireless receiver system30. Functionality of the receiver controller38may be implemented in hardware and/or software and may rely on one or more data maps relating to the operation of the wireless receiver system30. To that end, the receiver controller38may be operatively associated with the memory37. The memory may include one or both of internal memory, external memory, and/or remote memory (e.g., a database and/or server operatively connected to the receiver controller38via a network, such as, but not limited to, the Internet). The internal memory and/or external memory may include, but are not limited to including, one or more of a read only memory (ROM), including programmable read-only memory (PROM), erasable programmable read-only memory (EPROM or sometimes but rarely labelled EROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDR SDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data rate synchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5), a flash memory, a portable memory, and the like. Such memory media are examples of nontransitory computer readable memory media. Further, while particular elements of the receiver control system36are illustrated as subcomponents and/or circuits (e.g., the memory37, the communications system39, among other contemplated elements) of the receiver control system36, such components may be external of the receiver controller38. In some examples, the receiver controller38may be and/or include one or more integrated circuits configured to include functional elements of one or both of the receiver controller38and the wireless receiver system30, generally. As used herein, the term “integrated circuits” generally refers to a circuit in which all or some of the circuit elements are inseparably associated and electrically interconnected so that it is considered to be indivisible for the purposes of construction and commerce. Such integrated circuits may include, but are not limited to including, thin-film transistors, thick-film technologies, and/or hybrid integrated circuits. FIG.11illustrates an example, non-limiting embodiment of one or both of the transmitter antenna21and/or the receiver antenna31that may be used with any of the systems, methods, and/or apparatus disclosed herein. In the illustrated embodiment, the antenna21,31, is a flat spiral coil configuration. Non-limiting examples can be found in U.S. Pat. Nos. 9,941,743, 9,960,628, 9,941,743 all to Peralta et al.; 9,948,129, 10,063,100 to Singh et al.; U.S. Pat. No. 9,941,590 to Luzinski; U.S. Pat. No. 9,960,629 to Rajagopalan et al.; and U.S. Patent App. Nos. 2017/0040107, 2017/0040105, 2017/0040688 to Peralta et al.; all of which are assigned to the assignee of the present application and incorporated fully herein by reference. In addition, the antenna21,31may be constructed having a multi-layer-multi-turn (MLMT) construction in which at least one insulator is positioned between a plurality of conductors. Non-limiting examples of antennas having an MLMT construction that may be incorporated within the wireless transmission system(s)20and/or the wireless receiver system(s)30may be found in U.S. Pat. Nos. 8,610,530, 8,653,927, 8,680,960, 8,692,641, 8,692,642, 8,698,590, 8,698,591, 8,707,546, 8,710,948, 8,803,649, 8,823,481, 8,823,482, 8,855,786, 8,898,885, 9,208,942, 9,232,893, and 9,300,046 to Singh et al., all of which are assigned to the assignee of the present application are incorporated fully herein. These are merely exemplary antenna examples; however, it is contemplated that the antennas31may be any antenna capable of the aforementioned higher power, high frequency wireless power transfer. FIG.12is an example block diagram for a method1000of designing a system for wirelessly transferring one or more of electrical energy, electrical power, electromagnetic energy, and electronic data, in accordance with the systems, methods, and apparatus of the present disclosure. To that end, the method1000may be utilized to design a system in accordance with any disclosed embodiments of the system10and any components thereof. At block1200, the method1000includes designing a wireless transmission system for use in the system10. The wireless transmission system designed at block1200may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless transmission system20, in whole or in part and, optionally, including any components thereof. Block1200may be implemented as a method1200for designing a wireless transmission system. Turning now toFIG.13and with continued reference to the method1000ofFIG.12, an example block diagram for the method1200for designing a wireless transmission system is illustrated. The wireless transmission system designed by the method1200may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless transmission system20in whole or in part and, optionally, including any components thereof. The method1200includes designing and/or selecting a transmission antenna for the wireless transmission system, as illustrated in block1210. The designed and/or selected transmission antenna may be designed and/or selected in accordance with one or more of the aforementioned and disclosed embodiments of the transmission antenna21, in whole or in part and including any components thereof. The method1200also includes designing and/or tuning a transmission tuning system for the wireless transmission system, as illustrated in block1220. Such designing and/or tuning may be utilized for, but not limited to being utilized for, impedance matching, as discussed in more detail above. The designed and/or tuned transmission tuning system may be designed and/or tuned in accordance with one or more of the aforementioned and disclosed embodiments of wireless transmission system20, in whole or in part and, optionally, including any components thereof. The method1200further includes designing a power conditioning system for the wireless transmission system20,120, as illustrated in block1230. The power conditioning system designed may be designed with any of a plurality of power output characteristic considerations, such as, but not limited to, power transfer efficiency, maximizing a transmission gap (e.g., the gap17), increasing output voltage to a receiver, mitigating power losses during wireless power transfer, increasing power output without degrading fidelity for data communications, optimizing power output for multiple coils receiving power from a common circuit and/or amplifier, among other contemplated power output characteristic considerations. The power conditioning system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the power conditioning system40, in whole or in part and, optionally, including any components thereof. Further, at block1240, the method1200may involve determining and/or optimizing a connection, and any associated connection components, between the input power source12and the power conditioning system that is designed at block1230. Such determining and/or optimizing may include selecting and implementing protection mechanisms and/or apparatus, selecting and/or implementing voltage protection mechanisms, among other things. The method1200further includes designing and/or programing a transmission control system of the wireless transmission system of the method1000, as illustrated in block1250. The designed transmission control system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the transmission control system26, in whole or in part and, optionally, including any components thereof. Such components thereof include, but are not limited to including, the sensing system50, the driver41, the transmission controller28, the memory27, the communications system29, the thermal sensing system52, the object sensing system54, the receiver sensing system56, the other sensor(s)58, the gate voltage regulator43, the PWM generator41, the frequency generator348, in whole or in part and, optionally, including any components thereof. Returning now toFIG.12, at block1300, the method1000includes designing a wireless receiver system for use in the system10. The wireless transmission system designed at block1300may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless receiver system30in whole or in part and, optionally, including any components thereof. Block1300may be implemented as a method1300for designing a wireless receiver system. Turning now toFIG.14and with continued reference to the method1000ofFIG.12, an example block diagram for the method1300for designing a wireless receiver system is illustrated. The wireless receiver system designed by the method1300may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless receiver system30in whole or in part and, optionally, including any components thereof. The method1300includes designing and/or selecting a receiver antenna for the wireless receiver system, as illustrated in block1310. The designed and/or selected receiver antenna may be designed and/or selected in accordance with one or more of the aforementioned and disclosed embodiments of the receiver antenna31, in whole or in part and including any components thereof. The method1300includes designing and/or tuning a receiver tuning system for the wireless receiver system, as illustrated in block1320. Such designing and/or tuning may be utilized for, but not limited to being utilized for, impedance matching, as discussed in more detail above. The designed and/or tuned receiver tuning system may be designed and/or tuned in accordance with one or more of the aforementioned and disclosed embodiments of the receiver tuning and filtering system34in whole or in part and/or, optionally, including any components thereof. The method1300further includes designing a power conditioning system for the wireless receiver system, as illustrated in block1330. The power conditioning system may be designed with any of a plurality of power output characteristic considerations, such as, but not limited to, power transfer efficiency, maximizing a transmission gap (e.g., the gap17), increasing output voltage to a receiver, mitigating power losses during wireless power transfer, increasing power output without degrading fidelity for data communications, optimizing power output for multiple coils receiving power from a common circuit and/or amplifier, among other contemplated power output characteristic considerations. The power conditioning system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the power conditioning system32in whole or in part and, optionally, including any components thereof. Further, at block1340, the method1300may involve determining and/or optimizing a connection, and any associated connection components, between the load16and the power conditioning system of block1330. Such determining may include selecting and implementing protection mechanisms and/or apparatus, selecting and/or implementing voltage protection mechanisms, among other things. The method1300further includes designing and/or programing a receiver control system of the wireless receiver system of the method1300, as illustrated in block1350. The designed receiver control system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the receiver control system36in whole or in part and, optionally, including any components thereof. Such components thereof include, but are not limited to including, the receiver controller38, the memory37, and the communications system39, in whole or in part and, optionally, including any components thereof. Returning now to the method1000ofFIG.12, the method1000further includes, at block1400, optimizing and/or tuning both the wireless transmission system and the wireless receiver system for wireless power transfer. Such optimizing and/or tuning includes, but is not limited to including, controlling and/or tuning parameters of system components to match impedance, optimize and/or set voltage and/or power levels of an output power signal, among other things and in accordance with any of the disclosed systems, methods, and apparatus herein. Further, the method1000includes optimizing and/or tuning one or both of the wireless transmission system and the wireless receiver system for data communications, in view of system characteristics necessary for wireless power transfer. Such optimizing and/or tuning includes, but is not limited to including, optimizing power characteristics for concurrent transmission of electrical power signals and electrical data signals, tuning quality factors of antennas for different transmission schemes, among other things and in accordance with any of the disclosed systems, methods, and apparatus herein. FIG.15is an example block diagram for a method2000for manufacturing a system for wirelessly transferring one or both of electrical power signals and electrical data signals, in accordance with the systems, methods, and apparatus of the present disclosure. To that end, the method2000may be utilized to manufacture a system in accordance with any disclosed embodiments of the system10and any components thereof. At block2200, the method2000includes manufacturing a wireless transmission system for use in the system10. The wireless transmission system manufactured at block2200may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless transmission system20in whole or in part and, optionally, including any components thereof. Block2200may be implemented as a method2200for manufacturing a wireless transmission system. Turning now toFIG.16and with continued reference to the method2000ofFIG.15, an example block diagram for the method2200for manufacturing a wireless transmission system is illustrated. The wireless transmission system manufactured by the method2200may be manufactured in accordance with one or more of the aforementioned and disclosed embodiments of the wireless transmission system20in whole or in part and, optionally, including any components thereof. The method2200includes manufacturing a transmission antenna for the wireless transmission system, as illustrated in block2210. The manufactured transmission system may be built and/or tuned in accordance with one or more of the aforementioned and disclosed embodiments of the transmission antenna21, in whole or in part and including any components thereof. The method2200also includes building and/or tuning a transmission tuning system for the wireless transmission system, as illustrated in block2220. Such building and/or tuning may be utilized for, but not limited to being utilized for, impedance matching, as discussed in more detail above. The built and/or tuned transmission tuning system may be designed and/or tuned in accordance with one or more of the aforementioned and disclosed embodiments of the transmission tuning system24, in whole or in part and, optionally, including any components thereof. The method2200further includes selecting and/or connecting a power conditioning system for the wireless transmission system, as illustrated in block2230. The power conditioning system manufactured may be designed with any of a plurality of power output characteristic considerations, such as, but not limited to, power transfer efficiency, maximizing a transmission gap (e.g., the gap17), increasing output voltage to a receiver, mitigating power losses during wireless power transfer, increasing power output without degrading fidelity for data communications, optimizing power output for multiple coils receiving power from a common circuit and/or amplifier, among other contemplated power output characteristic considerations. The power conditioning system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the power conditioning system40in whole or in part and, optionally, including any components thereof. Further, at block2240, the method2200involve determining and/or optimizing a connection, and any associated connection components, between the input power source12and the power conditioning system of block2230. Such determining may include selecting and implementing protection mechanisms and/or apparatus, selecting and/or implementing voltage protection mechanisms, among other things. The method2200further includes assembling and/or programing a transmission control system of the wireless transmission system of the method2000, as illustrated in block2250. The assembled transmission control system may be assembled and/or programmed in accordance with one or more of the aforementioned and disclosed embodiments of the transmission control system26in whole or in part and, optionally, including any components thereof. Such components thereof include, but are not limited to including, the sensing system the driver41, the transmission controller28, the memory27, the communications system29, the thermal sensing system52, the object sensing system54, the receiver sensing system56, the other sensor(s)58, the gate voltage regulator43, the PWM generator41, the frequency generator348, in whole or in part and, optionally, including any components thereof. Returning now toFIG.15, at block2300, the method2000includes manufacturing a wireless receiver system for use in the system10. The wireless transmission system manufactured at block2300may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless receiver system30in whole or in part and, optionally, including any components thereof. Block2300may be implemented as a method2300for manufacturing a wireless receiver system. Turning now toFIG.17and with continued reference to the method2000ofFIG.14, an example block diagram for the method2300for manufacturing a wireless receiver system is illustrated. The wireless receiver system manufactured by the method2300may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the wireless receiver system30in whole or in part and, optionally, including any components thereof. The method2300includes manufacturing a receiver antenna for the wireless receiver system, as illustrated in block2310. The manufactured receiver antenna may be manufactured, designed, and/or selected in accordance with one or more of the aforementioned and disclosed embodiments of the receiver antenna31in whole or in part and including any components thereof. The method2300includes building and/or tuning a receiver tuning system for the wireless receiver system, as illustrated in block2320. Such building and/or tuning may be utilized for, but not limited to being utilized for, impedance matching, as discussed in more detail above. The built and/or tuned receiver tuning system may be designed and/or tuned in accordance with one or more of the aforementioned and disclosed embodiments of the receiver tuning and filtering system34in whole or in part and, optionally, including any components thereof. The method2300further includes selecting and/or connecting a power conditioning system for the wireless receiver system, as illustrated in block2330. The power conditioning system designed may be designed with any of a plurality of power output characteristic considerations, such as, but not limited to, power transfer efficiency, maximizing a transmission gap (e.g., the gap17), increasing output voltage to a receiver, mitigating power losses during wireless power transfer, increasing power output without degrading fidelity for data communications, optimizing power output for multiple coils receiving power from a common circuit and/or amplifier, among other contemplated power output characteristic considerations. The power conditioning system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the power conditioning system32in whole or in part and, optionally, including any components thereof. Further, at block2340, the method2300may involve determining and/or optimizing a connection, and any associated connection components, between the load16and the power conditioning system of block2330. Such determining may include selecting and implementing protection mechanisms and/or apparatus, selecting and/or implementing voltage protection mechanisms, among other things. The method2300further includes assembling and/or programing a receiver control system of the wireless receiver system of the method2300, as illustrated in block2350. The assembled receiver control system may be designed in accordance with one or more of the aforementioned and disclosed embodiments of the receiver control system36in whole or in part and, optionally, including any components thereof. Such components thereof include, but are not limited to including, the receiver controller38, the memory37, and the communications system39, in whole or in part and, optionally, including any components thereof. Returning now to the method2000ofFIG.15, the method2000further includes, at block2400, optimizing and/or tuning both the wireless transmission system and the wireless receiver system for wireless power transfer. Such optimizing and/or tuning includes, but is not limited to including, controlling and/or tuning parameters of system components to match impedance, optimize and/or configure voltage and/or power levels of an output power signal, among other things and in accordance with any of the disclosed systems, methods, and apparatus herein. Further, the method2000includes optimizing and/or tuning one or both of the wireless transmission system and the wireless receiver system for data communications, in view of system characteristics necessary for wireless power transfer, as illustrated at block2500. Such optimizing and/or tuning includes, but is not limited to including, optimizing power characteristics for concurrent transmission of electrical power signals and electrical data signals, tuning quality factors of antennas for different transmission schemes, among other things and in accordance with any of the disclosed systems, methods, and apparatus herein. The systems, methods, and apparatus disclosed herein are designed to operate in an efficient, stable and reliable manner to satisfy a variety of operating and environmental conditions. The systems, methods, and/or apparatus disclosed herein are designed to operate in a wide range of thermal and mechanical stress environments so that data and/or electrical energy is transmitted efficiently and with minimal loss. In addition, the system10may be designed with a small form factor using a fabrication technology that allows for scalability, and at a cost that is amenable to developers and adopters. In addition, the systems, methods, and apparatus disclosed herein may be designed to operate over a wide range of frequencies to meet the requirements of a wide range of applications. In an embodiment, a ferrite shield may be incorporated within the antenna structure to improve antenna performance. Selection of the ferrite shield material may be dependent on the operating frequency as the complex magnetic permeability (μ=μ′−j*μ″) is frequency dependent. The material may be a polymer, a sintered flexible ferrite sheet, a rigid shield, or a hybrid shield, wherein the hybrid shield comprises a rigid portion and a flexible portion. Additionally, the magnetic shield may be composed of varying material compositions. Examples of materials may include, but are not limited to, zinc comprising ferrite materials such as manganese-zinc, nickel-zinc, copper-zinc, magnesium-zinc, and combinations thereof. As used herein, the phrase “at least one of” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” does not require selection of at least one of each item listed; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. The predicate words “configured to”, “operable to”, and “programmed to” do not imply any particular tangible or intangible modification of a subject, but, rather, are intended to be used interchangeably. In one or more embodiments, a processor configured to monitor and control an operation or a component may also mean the processor being programmed to monitor and control the operation or the processor being operable to monitor and control the operation. Likewise, a processor configured to execute code can be construed as a processor programmed to execute code or operable to execute code. A phrase such as “an aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples of the disclosure. A phrase such as an “aspect” may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples of the disclosure. A phrase such an “embodiment” may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples of the disclosure. A phrase such as a “configuration” may refer to one or more configurations and vice versa. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” or as an “example” is not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the subject disclosure. While this specification contains many specifics, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of particular implementations of the subject matter. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub combination or variation of a sub combination. | 80,219 |
11862995 | DETAILED DESCRIPTION The terms used in the disclosure are used to describe various example embodiments, and are not intended to limit the disclosure. A singular expression may include a plural expression unless they are clearly different in context. All terms used herein, including technical and scientific terms, have the same meaning as those commonly understood by a person skilled in the art to which the disclosure pertains. Such terms as those defined in a generally used dictionary may be interpreted to have the meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the disclosure. In some cases, even where the term is defined in the disclosure, it should not be interpreted to exclude embodiments of the disclosure. FIG.1is a block diagram illustrating an example wireless power transmission device and an electronic device according to various embodiments. Referring toFIG.1, a wireless power transmission device100according to various embodiments may wirelessly transmit power161to an electronic device150. The wireless power transmission device100may transmit the power161to the electronic device150according to various charging schemes. For example, the wireless power transmission device100may transmit the power161according to an induction scheme. However, it will be understood that the disclosure is not limited thereto. When the wireless power transmission device100is based on the induction scheme, the wireless power transmission device100may include, for example, a power source, a DC-AC converting circuit, an amplification circuit, an impedance matching circuit, at least one capacitor, at least one coil, a communication modulation/demodulation circuit, and the like. At least one capacitor may configure a resonance circuit with at least one coil. The wireless power transmission device100may, for example, and without limitation, be implemented in a manner defined in the Wireless Power Consortium (WPC) standard (or Qi standard). For example, the wireless power transmission device100may transmit the power161according, for example, and without limitation, to a resonance scheme. According to the resonance scheme, the wireless power transmission device100may include, for example, a power source, a DC-AC converting circuit, an amplification circuit, an impedance matching circuit, at least one capacitor, at least one coil, an out-band communication circuit (for example, a Bluetooth Low Energy (BLE) communication circuit), and the like. At least one capacitor and at least one coil may configure a resonance circuit. The wireless power transmission device100may be implemented, for example, and without limitation, in a manner defined in the Alliance for Wireless Power (A4WP) standard (or Air Fuel Alliance (AFA)). The wireless power transmission device100may include a coil that can generate an induced magnetic field when the current flows according to the resonance scheme or the induction scheme. A process in which the wireless power transmission device100generates the induced magnetic field may be expressed as wireless transmission of the power161by the wireless power transmission device100. Further, the electronic device150may include a coil for generating an induced electromotive force by a magnetic field formed therearound, of which the magnitude is changed according to the time. A process in which the electronic device150generates the induced electromotive force through the coil may be expressed as wireless reception of the power161by the electronic device150. For example, the wireless power transmission device100may transmit the power161according, for example, and without limitation, to an electromagnetic scheme. When the wireless power transmission device100is based on the electromagnetic scheme, the wireless power transmission device100may include, for example, a power source, a DC-AC converting circuit, an amplification circuit, a distribution circuit, a phase shifter, a power transmission antenna array including a plurality of patch antennas, an out-band communication circuit (for example, a BLE communication module), and the like. Each of the plurality of patch antennas may form Radio Frequency (RF) waves (for example, electromagnetic waves). The electronic device150may include a patch antenna capable of outputting the current using the RF waves formed therearound. A process in which the wireless power transmission device100forms the RF waves may be expressed as wireless transmission of the power161by the wireless power transmission device100. A process in which the electronic device150outputs the current from the patch antenna using the RF waves may be expressed as wireless reception of the power161by the electronic device150. The wireless power transmission device100according to various embodiments may communicate with the electronic device150. For example, the wireless power transmission device100may communication with the electronic device150according to an in-band scheme. The wireless power transmission device100or the electronic device150may change a load (or impedance) of data to be transmitted according to, for example, an on/off keying modulation scheme. The wireless power transmission device100or the electronic device150may measure a load change (or impedance change) on the basis of a change in the magnitude of the current, voltage, or power of the coil, to determine data transmitted by a counterpart device. For example, the wireless power transmission device100may communicate with the electronic device150according to an out-band scheme. The wireless power transmission device100or the electronic device150may transmit and receive data using a communication circuit (for example, a BLE communication module) separated from the coil or the patch antenna. In the disclosure, the performance of a specific operation by the wireless power transmission device100, the electronic device150, or another electronic device may refer, for example, to the performance of the specific operation by various hardware devices included in the wireless power transmission device100, the electronic device150, or another electronic device, for example, a control circuit such as a processor, a coil, a patch antenna, or the like. The the performance of a specific operation by the wireless power transmission device100, the electronic device150, or another electronic device may refer, for example, to the processor controlling another hardware device to perform the specific operation. The performance of a specific operation by the wireless power transmission device100, the electronic device150, or another electronic device may refer, for example, to instructions stored in a storage circuit (for example, a memory) of the wireless power transmission device100, the electronic device150, or another electronic device to perform the specific operation causing the processor or another hardware device to perform the specific operation when the instruction is executed. FIG.2is a block diagram illustrating an example wireless power transmission device and an electronic device according to various embodiments. The wireless power transmission device100according to various embodiments may include a power transmission circuit109, a control circuit102, a communication circuit103, a memory105, and a power source106. The electronic device150according to various embodiments may include a power reception circuit159, a control circuit152, a communication circuit153, a memory156, a charger154, a battery155, a Power Management Integrated Circuit (PMIC)158, and a load157. The power transmission circuit109according to various embodiments may wirelessly transmit power to the power reception circuit159according, for example, and without limitation, to at least one of the induction scheme, the resonance scheme, or the electromagnetic scheme. Example configurations of the power transmission circuit109and the power reception circuit159are described in greater detail below with reference toFIGS.3A and3B. The control circuit102may control the magnitude of power transmitted by the power transmission circuit109. For example, the control circuit102may control the magnitude of power output from the power source106or control an amplitude gain of a power amplifier included in the power transmission circuit109, to control the magnitude of the power transmitted by the power transmission circuit109. The control circuit102may adjust the magnitude of the power output from the power source106by controlling a duty cycle or a frequency of the power output from the power source106. The power source106may include, for example, a power interface which can be connected to a wall power source and may receive AC power having a voltage configured for each country from the wall power source and transmit the same to the power transmission circuit109. The control circuit102may control the magnitude of power applied to the power transmission circuit109by controlling the magnitude of a bias voltage of the power amplifier. The control circuit102or the control circuit152may be implemented as any of various processing circuitry, such as, for example, and without limitation, a general-purpose processor like a CPU, a dedicated processor, a mini computer, a microprocessor, a Micro Controlling Unit (MCU), a Field-Programmable Gate Array (FPGA) that may perform calculations, and the like but there is no limitation as to the type thereof. The power reception circuit159according to various embodiments may wirelessly receive power from the power transmission circuit109according, for example, and without limitation, to at least one of the induction scheme, the resonance scheme, or the electromagnetic scheme. For example, the power reception circuit159may include a power reception antenna for wirelessly receiving a power signal. The power reception circuit159may rectify received AC waveform power to DC waveform power, convert a voltage, or process power by regulating the power. According to various embodiments, the power reception circuit159may include at least one impedance matching circuit. According to an embodiment, the power reception circuit159may include a fixed impedance matching circuit configured to match impedance of power reception antennas. Further, the power reception circuit159may further include a variable adaptive impedance matching circuit connected to an output terminal of the fixed impedance matching circuit. For example, the adaptive impedance matching circuit may be configured to match impedance for power signals using one of a plurality of impedance values. According to various embodiments, the fixed impedance matching circuit may be implemented between the adaptive impedance matching circuit and the antenna, but may be omitted as necessary. Example configurations of the fixed impedance matching circuit and the adaptive impedance matching circuit are described in greater detail below with reference toFIG.4. The charger154may charge the battery155of the electronic device150. The charger154may charge the battery155in, for example, and without limitation, a Constant Voltage (CV) mode, a Constant Current (CC) mode, or the like, but there is no limitation as to the charging mode. The PMIC158may adjust a voltage or current suitable for the connected load157and provide the voltage or current to the load157. The control circuit152may control the overall operation of the electronic device150, and at least one processor may replace the control circuit152. The memory156may store instructions for performing the overall operation of the electronic device150. The memory105may store instructions for performing the operation of the wireless power transmission device100. The memory105or the memory156may be implemented in various forms such as, for example, and without limitation, a Read Only Memory (ROM), a Random Access Memory (RAM), a flash memory, and the like, but there is no limitation as to the implementation form thereof. According to various embodiments, the memory105may store instructions which, when executed, cause the at least one processor to perform control to change an impedance value of the impedance matching circuit to an impedance value learned using an impedance matching network model in accordance with a power and a frequency of the impedance-matched power signal. According to an embodiment, the impedance matching network model may be configured to sequentially acquire second impedance-matched power signals using the plurality of impedance values, identify a maximum power signal among the second impedance-matched power signals on the basis of comparison between powers of the second impedance-matched power signals, and change an impedance value of the second impedance matching circuit to the learned impedance value which is an impedance value corresponding to the maximum power signal among the plurality of impedance values. According to an embodiment, the impedance value leaned using the impedance matching network model may include an impedance value causing a maximum power of another power signal for a detected frequency and power among the plurality of impedance values on the basis of detection of a power and the frequency of the another power signal output from the impedance matching circuit. According to an embodiment, the impedance matching circuit may include a plurality of circuits corresponding to the plurality of impedance values, and the plurality of circuits may include at least one capacitor and at least one switch configured to switch a short circuit of the at least one capacitor. According to various embodiments, the electronic device150may include a power conversion circuit configured to convert the impedance-matched power signal in an AC form into a power in a DC form for a battery according to the changed impedance value. According to an embodiment, the power conversion circuit may be included in the power reception circuit159. According to various embodiments, the instructions may be configured to cause the at least one processor to detect an input power between an output terminal of the second impedance matching circuit and an input terminal of the power conversion circuit and an output power in an output terminal of the power conversion circuit and detect a frequency between the output terminal of the second impedance matching circuit and the input terminal of the power conversion circuit. According to various embodiments, the instructions may be configured to cause the at least one processor to compare the input power and the output power and store a learning result that matches an impedance value causing maximum power of a power signal output from the impedance matching circuit with the detected frequency on the basis of the comparison result. FIG.3Ais a block diagram illustrating an example power transmission circuit and a power reception circuit based on an induction scheme or a resonance scheme according to various embodiments. According to various embodiments, the power transmission circuit109may include a power generation circuit312and a coil313. The power generation circuit312may first rectify AC power received from the outside, invert the rectified power, and provide the power to the coil. Through the inverting operation, a maximum voltage or a value of 0 may be alternately applied to the coil313according to a preset period, and accordingly a magnetic field may be generated from the coil313. An inverting frequency, for example, a frequency in an AC waveform applied to the coil313, may be configured, for example, as 100 to 205 kHz or 6.78 MHz, and the like according to the standard, but there is no limitation thereto. When power is applied to the coil313, an induced magnetic field, of which the magnitude is changed according to the time, may be formed by the coil313, and accordingly power may be wirelessly transmitted. Although not illustrated, capacitors configuring the resonance circuit with the coil313may be further included in the power transmission circuit109. In the coil321of the power reception circuit159, an induced electromotive force may be generated by the magnetic field formed therearound of which the magnitude is changed according to the time, and accordingly the power reception circuit159may wirelessly receive power. The rectification circuit322may rectify the received AC waveform power. A converting circuit323may adjust a voltage of the rectified power and transfer the voltage to hardware. The power reception circuit159may further include a regulator, or the converting circuit323may be replaced with the regulator. FIG.3Bis a block diagram illustrating an example power transmission circuit and a power reception circuit based on an electromagnetic scheme according to various embodiments. According to various embodiments, the power transmission circuit109may include an amplification circuit331, a distribution circuit332, a phase shifter (e.g., including phase shifting circuitry)333, and a power transmission antenna array334. In various embodiments, the power reception circuit159may include a power reception antenna341, a rectification circuit342, and a converting circuit343. The amplification circuit331may amplify power received from the power source106and provide the power to the distribution circuit332. The amplification circuit331may be implemented as various amplifiers such as, for example, a Drive Amplifier (DA), a High Power Amplifier (HPA), a Gain Block Amplifier (GBA), and the like, or a combination thereof, but there is no limitation as to an implementation example thereof. The distribution circuit332may distribute power output from the amplification circuit331to a plurality of paths. Any circuit capable of distributing input power or signal to a plurality of paths can be the distribution circuit332. For example, the distribution circuit332may distribute power to paths corresponding to the number of patch antennas included in the power transmission antenna array334. The phase shifter333may include various phase shifting circuitry and shift a phase (or delay) of each of a plurality of AC powers provided from the distribution circuit332. The number of phase shifters333may be plural, and may correspond to the number of patch antennas included in the power transmission antenna array334. For example, and without limitation, a hardware element such as HMC642, HMC1113, or the like may be used as the phase shifter333. Each shift degree by the phase shifter333may be controlled by the control circuit102. The control circuit102may determine the location of the electronic device150and shift a phase of each of a plurality of AC powers in order to allow RF waves to constructively interfere, for example, to be beamformed at the location of the electronic device150(or the location of the power reception antenna341of the electronic device150). Each of the plurality of patch antennas included in the power transmission antenna array334may generate sub RF waves on the basis of received power. RF waves interfered by the sub RF waves may be converted to the current, voltage, or power by the power reception antenna341and then output. The power reception antenna341may include a plurality of patch antennas and generate the current, voltage, or power of the AC waveform using the RF waves formed therearound, that is, electromagnetic waves, which may be named received power. The rectification circuit342may rectify the received power in the DC waveform. The converting circuit343may increase or decrease a voltage of the power in the DC waveform to a preset value and output the same to the PMIC158. At least one of the power transmission circuit109or the power reception circuit159according to various embodiments may include all of a hardware device based on the induction scheme or the resonance scheme ofFIG.3Aand a hardware device based on the electromagnetic scheme ofFIG.3B. In this case, the control circuit102or the control circuit152may select a charging scheme according to various conditions and control hardware corresponding to the selected charging scheme to be driven. The control circuit102or the control circuit152may use all of the induction scheme or the resonance scheme, and the electromagnetic scheme, and may drive all of the included hardware devices to transmit and receive power. The coil321for outputting AC power using a magnetic field therearound or the power reception antenna341for outputting AC power using RF waves therearound may be named a reception circuit. According to various embodiments, the power reception circuit159ofFIG.2may be implemented as the power reception circuit according to the induction scheme or the resonance scheme as illustrated inFIG.3Aor implemented as the power reception circuit according to the electromagnetic scheme as illustrated inFIG.3B, and such a power reception circuit159may be referred to as an energy harvesting circuit (circuitry) (or an energy harvesting module). The energy harvesting circuit according to various embodiments may include at least one energy conversion module capable of converting energy therearound into electrical energy and include a module for various energy conversions such as the induction scheme, the resonance scheme, or the electromagnetic scheme, but it may be easily understood by those skilled in the art that there is no limitation as to the type of the energy conversion module. The energy harvesting circuit may be applied to various electronic devices which need power, and impedance matching may be important to maximize efficiency of energy harvesting from various energy sources. In general, the impedance matching circuit is implemented as one matching end optimized for a single input, and the impedance matching is to apply maximum and/or improved power. The energy harvesting technology receives energy such as RF waves in the air, uses the energy as power of the electronic device, and thus secures energy without a separate energy supply, but may need each impedance matching end and an individual array antenna in order to secure energy of RF signals in various frequency bands and also it is cumbersome to manually control impedance matching one by one. Hereinafter, an example embodiment of tracking an impedance matching value optimized for various energy sources, for example, input power in various frequency bands and changing the same using an automatically stored impedance matching value is described in greater detail below with reference toFIG.4. FIG.4is a block diagram illustrating an example electronic device for adaptive impedance matching according to various embodiments. Referring toFIG.4, an electronic device400(for example, the electronic device150ofFIG.1) may include an antenna401, a first impedance matching circuit (circuitry)402, a second impedance matching circuit403, a control circuit404, a power conversion circuit405, and a battery408. According to various embodiments, a configuration including the second impedance matching circuit403, the control circuit404, and the power conversion circuit405may be referred to as an energy harvesting circuit410. According to various embodiments, the energy harvesting circuit410may include at least one energy conversion module capable of converting energy therearound into electrical energy. According to an embodiment, the second impedance matching circuit403, the control circuit404, and the power conversion circuit405may be independently included in the electronic device400or included in the electronic device400in the form of an Integrated Chip (IC). The antenna401may be a power reception antenna circuit (wireless power antenna circuitry) and may output AC power using RF waves formed therearound. The antenna401may be connected to the first impedance matching circuit402to be operable. The antenna401may output the wirelessly received AC power to an input terminal of the first impedance matching circuit402. The first impedance matching circuit402may include at least one of at least one capacitor or at least one coil. The first impedance matching circuit402may perform impedance matching between the electronic device400and the wireless power transmission device100. The first impedance matching circuit402may be configured to match impedance (or load) connected to the antenna401. The first impedance matching circuit402may be a fixed impedance matching circuit connected to the antenna401to be operable. For example, the first impedance matching circuit402may be configured to match impedance (for example, 50Ω) of the wireless power transmission device100with the antenna401. According to an embodiment, the first impedance matching circuit402may be referred to as a fixed impedance matching circuit. According to an embodiment, since impedance matching is performed by the second impedance matching circuit403, the first impedance matching circuit402may be omitted. However, when the environment is changed according to the lapse of time, impedance matching efficiency through fixed impedance matching may be reduced. In order to compensate for the change, the adjustable second impedance matching circuit403may be used. The second impedance matching circuit403may output a signal which is closest to input power, that is, a maximum power signal having no loss by outputting a signal which is more precisely adjusted for an input frequency, that is, an additional impedance matching signal. The control circuit404according to various embodiments may determine when and how to control impedance matching of the second impedance matching circuit403. To this end, the control circuit404may control the second impedance matching circuit403for corresponding impedance on the basis of a frequency of a signal transmitted through the second impedance matching circuit403and the magnitude of power. Alternatively, the control circuit404may control the second impedance matching circuit403to perform specific impedance matching selected on the basis of the frequency of the signal transmitted through the antenna401or the first impedance matching circuit402and the magnitude of power of the signal transmitted through the second impedance matching circuit403. Further, the control circuit404may control the second impedance matching circuit403with reference to not only the frequency of the signal transmitted through the second impedance matching circuit403and the magnitude of power but also the magnitude of power of a signal output from the power conversion circuit405or an RF-DC converter406of the power conversion circuit405. According to various embodiments, the control circuit404may determine when and how much the second impedance matching circuit403is adjusted using a matching network model. A control signal (or command) indicating which impedance matching of the second impedance matching circuit403is performed may be determined using a learning model learned through an artificial intelligence algorithm. The artificial intelligence algorithm may be referred to as an impedance matching network model, and the impedance matching network model may be a model learned using an algorithm technology for classifying/learning characteristics of detected power signals by itself such as machine learning. Hereinafter, the case in which an output terminal of the first impedance matching circuit402is connected to an input terminal of the second impedance matching circuit403is described by way of example. According to various embodiments, the energy harvesting circuit410may be configured to perform additional impedance matching in order to provide maximum efficiency for power received through the first impedance matching circuit402. To this end, the energy harvesting circuit410may include the second impedance matching circuit403, the control circuit404, and the power conversion circuit405. According to various embodiments, the second impedance matching circuit403may perform impedance matching for a power signal from the output terminal of the first impedance matching circuit402. The second impedance matching circuit403may perform impedance matching to maximize power measured at the output terminal of the power conversion module405or the output terminal of the second impedance matching circuit403. To this end, the second impedance matching circuit403may perform impedance matching using one of a plurality of impedance values for a power signal received from the first impedance matching circuit402under the control of the control circuit404. According to various embodiments, the second impedance matching circuit403may include a plurality of circuits corresponding to a plurality of impedance values. According to an embodiment, the plurality of circuits may include at least one capacitor and at least one switch, and the switch may switch a short circuit of the at least one capacitor. As the control circuit404controls a switching element of the second impedance matching circuit403, the output terminal of the first impedance matching circuit402may be connected to one capacitor of the second impedance matching circuit403and an impedance matching power signal may be input into an input terminal of the power conversion module405through the connected capacitor. As described above, the second impedance matching circuit403may include adaptive impedance matching elements having impedance values changed according to a control signal of the control circuit404. According to an embodiment, the second impedance matching circuit403may be referred to as an adaptive impedance matching circuit. According to various embodiments, when impedance matching is primarily performed through the first impedance matching circuit402, secondary impedance matching may be performed through the second impedance matching circuit403in order to output maximum and/or improved efficiency of the primarily impedance-matched power signal. At this time, the control of the second impedance matching circuit403may be performed by the control circuit404, and the control circuit404may control the second impedance matching circuit403through an impedance matching configuration identified by an input frequency (or a reception frequency) and input power (or received power), thereby performing impedance matching having the maximum efficiency. According to various embodiments, the energy harvesting circuit410may adjust an impedance matching value to obtain maximum power using an electrical characteristic of a source, for example, a frequency and the magnitude of power. According to various embodiments, even though the number of sources is plural and the sources have a multi-connection structure in which the sources are connected, impedance matching to obtain the maximum power can be performed. According to various embodiments, the control circuit404may sequentially acquire the magnitude of power and a frequency of a power signal output from the second impedance matching circuit403, compare powers of second impedance-matched power signals, identify a maximum power signal among the second impedance-matched power signals on the basis of the comparison result, and update an impedance value corresponding to the maximum power signal to an impedance value learned for the detected frequency. Accordingly, the control circuit404may output a control signal that allows the impedance value corresponding to the maximum power signal among a plurality of impedance values of the second impedance matching circuit403, which can be combined, to be the impedance value of the second impedance matching circuit403. Further, when the impedance matching network model is learned, the control circuit404may use power signals output through the power conversion module405as well as power signals output from the second impedance matching circuit403. For example, power magnitudes and frequencies of power signals output from the second impedance matching circuit403and power signals output through the power conversion module405may be compared each other, and a control signal for controlling the second impedance matching circuit403using an impedance matching network model on the basis of the comparison result may be output. According to an embodiment, the control circuit404may control on/off of at least one switch within the second impedance matching circuit403by a control signal, output maximum power through impedance matching changed by the control signal, and charge the battery408with the maximum power. According to an embodiment, the control circuit404may correspond to the control circuit152ofFIG.2for controlling the overall operation of the electronic device400. The control circuit404may be a control circuit implemented for the purpose of controlling only the second impedance matching circuit403. For example, the control circuit404may control an on/off state of each or a combination of at least one switching element within the second impedance matching circuit403. According to various embodiments, the change in the impedance matching value corresponding to the frequency of received power and detected power may be performed by a control circuit in real time on the basis of an adjustable impedance matching network model. The control circuit404may adjust the second impedance matching circuit403in real time on the basis of how impedance matching is performed through the second impedance matching circuit403. According to various embodiments, the control circuit404may perform control to make the change to the learned impedance matching value in real time in accordance with the frequency of received power and detected power. According to an embodiment, when the change (variation) in at least one of the frequency of received power and the magnitude of power is detected, the impedance matching value may be controlled to be changed to the learned impedance matching value corresponding to the detected power and frequency. The control circuit404may continuously monitor the frequency of received power and the power when there is no change (variation) in at least one of the frequency of received power and the magnitude of power rather than changing the impedance matching value whenever the frequency of received power and the power are detected, and may not output a control signal for changing the impedance value to the second impedance matching circuit403during the continuous monitoring. According to an embodiment, when the detected change in the frequency is larger than or equal to a frequency threshold or when the detected change in the power is larger than or equal to a power threshold, a control signal for changing the impedance value may be output to the second impedance matching circuit403. For example, when the frequency is changed or output power, that is, detected power is reduced by a threshold or more, the control circuit404may change the impedance value to a default value and then perform again the operation of detecting the output frequency and power of the second impedance matching circuit403. Subsequently, the control circuit404may load an impedance value which may cause maximum power in accordance with the output frequency and power detected after the change to the default value and control the second impedance matching circuit403to perform impedance matching with the loaded impedance value. According to various embodiments, the control circuit404may control the second impedance matching circuit403through the adjustable impedance matching network model and thus reduce a time spent for finding the impedance matching value, thereby implementing a fast energy harvesting system having the maximum efficiency. According to various embodiments, the power conversion circuit405may convert the received power signal into charging power of the battery (or load)408. The power conversion circuit405may include at least one of the RF-DC converter406and the regulator407. According to various embodiments, the power signal output through impedance matching by the second impedance matching circuit403is a signal in the AC form, and thus the power conversion circuit405may include the RF-DC converter406configured to rectify the AC signal to DC power by the output voltage. As described above, the RF-DC converter406may convert the AC power to the DC form and may be replaced with a regulator for primarily rectifying AC power. The RF-DC converter406may include elements such as, for example, and without limitation, a partial or complete regulator, a bridge, and a switching converter. Further, the power conversion circuit405may include the regulator407configured to convert the rectified power signal into an energy potential (for example, voltage) compatible with the battery408, and the regulator407may be replaced with a DC-DC converter. The regulator407may serve to secondarily rectify the DC power primarily rectified by the RF-DC converter406. For example, the regulator407may convert the voltage of the rectified DC power to a desired level and output the voltage and, when the voltage value of the rectified DC power is larger or smaller than a voltage value desired for charging the battery408or driving the electronic device400, change the voltage of the rectified DC power into a desired voltage. The battery408may be connected to the energy harvesting circuit410to be operable. The battery408may store energy using power output from the regulator407. AlthoughFIG.4illustrates the battery408, a driving circuit or load for performing various operations of the load or the electronic device400may be included instead of the battery408. According to various embodiments, the electronic device400may include a first impedance matching circuit402configured to perform first impedance matching on a power signal wirelessly received from a wireless power transmission device100, a second impedance matching circuit403configured to perform second impedance matching on the first impedance-matched power signal using one of a plurality of impedance values, a control circuit404configured to perform control to change an impedance value of the second impedance matching circuit to an impedance value learned using an impedance matching network model in accordance with a power and a frequency of the second impedance-matched power signal, and a power conversion circuit405configured to convert the second impedance-matched power signal in an AC form into a power in a DC form for a battery according to the changed impedance value. According to various embodiments, the impedance matching network model may be configured to sequentially acquire second impedance-matched power signals using the plurality of impedance values, identify a maximum power signal among the second impedance-matched power signals on the basis of a comparison between powers of the second impedance-matched power signals, and change the impedance value of the second impedance matching circuit to the learned impedance value, which is an impedance value corresponding to the maximum power signal, among the plurality of impedance values. According to various embodiments, the second impedance matching circuit403may include a plurality of circuits corresponding to the plurality of respective impedance values, and the plurality of circuits may include at least one capacitor and at least one switch configured to switch a short circuit of the at least one capacitor. According to various embodiments, the impedance value learned using the impedance matching network model may include an impedance value causing a maximum power of another power signal for a detected frequency among the plurality of impedance values on the basis of detection of a power and the frequency of the another power signal output from the second impedance matching circuit403. According to various embodiments, the control circuit404may be configured to perform control to detect power and a frequency of the second impedance-matched power signal in an input terminal of the power conversion circuit405, identify an impedance value corresponding to the detected power and frequency using the impedance matching network mode, and change the impedance value of the second impedance matching circuit403to the identified impedance value. According to various embodiments, the control circuit404may include a power detection circuit configured to detect an input power between an output terminal of the second impedance matching circuit403and an input terminal of the power conversion circuit405and an output power in an output terminal of the power conversion circuit405, and a frequency detection circuit configured to detect a frequency between the output terminal of the second impedance matching circuit403and the input terminal of the power conversion circuit. According to various embodiments, the control circuit404may be configured to compare the input power and the output power and update a learning result learned to match an impedance value causing a maximum power of a power signal output from the second impedance matching circuit403to the detected frequency on the basis of the comparison result. According to various embodiments, the power conversion circuit405may include an RF-DC converter406configured to convert a second impedance-matched power signal in an AC form to a DC form according to the changed impedance value. According to various embodiments, the power conversion circuit405may further include a regulator407configured to rectify the power signal in the DC form output from the RF-DC converter406to a voltage for the battery. FIG.5is a block diagram illustrating an example configuration of an energy harvesting circuit according to various embodiments. Referring toFIG.5, the energy harvesting circuit410may include the second impedance matching circuit403, the control circuit404, and the RF-DC converter406. Further, the energy harvesting circuit410may include a power detection circuit510and a frequency detection circuit520, and may further include the regulator407for converting a voltage required for charging the battery408. The power detection circuit510and the frequency detection circuit520may be implemented as one detector (or detection module). According to various embodiments, an RF input may be transferred to the second impedance matching circuit403. For example, the RF input may be a fixed impedance value for a power signal wirelessly received from the wireless power transmission device and may be an impedance-matched power signal. Accordingly, the primarily impedance-matched power signal may be input into the second impedance matching circuit403. According to various embodiments, the power signal impedance-matched through the second impedance matching circuit403is a power signal in the AC form (for example, RF-DCIN) and may be input into an input terminal of the RF-DC converter406. The input terminal of the RF-DC converter406may be connected to an output terminal of the second impedance matching circuit403, and an input terminal of the regulator407may be connected to an output terminal of the RF-DC converter406. Accordingly, the impedance-matched power signal in the AC form from the output terminal of the RF-DC converter406may be converted into a power signal in the DC form and input into the input terminal of the regulator407, and the regulator407may rectify the power signal in the DC form to charging power (for example, voltage) for the battery408and output the same. For example, in the energy harvesting circuit410, the regulator407may be directly connected to the RF-DC converter406for performing conversion to electrical energy. Alternatively, a DC-DC converter may be directly connected to the RF-DC converter406instead of the regulator407. The regulator407or the DC-DC converter may convert electrical energy received from the RF-DC converter406, for example, a voltage of the power in the DC form into a voltage required for charging the battery408. As illustrated inFIG.5, the second impedance matching circuit403may include at least one capacitor and at least one switching element. For example, when a first switching element is in an on state, impedance matching may be performed using a first capacitor connected to the first switching element. When a second switching element is in an on state, impedance matching may be performed using a second capacitor connected to the second switching element. When the second switching element is in an on state, impedance matching may be performed using a third capacitor connected to the third switching element. As described above, the impedance value may be changed by turning on or off each switching element, but the impedance value may be changed by controlling on/off of a combination of a plurality of switching elements. A combination of a plurality of switching elements which can be connected will be described in greater detail below with reference toFIG.6. As described above, it is possible to acquire and use higher efficiency power through impedance matching according to an input frequency and input power using a plurality of capacitors and switching elements between the power reception antenna and the power conversion circuit as the adaptive impedance matching circuit. In this case, the second impedance matching circuit403may output power having the magnitude of A through impedance matching by the connection of the first switching element, and when the power having the magnitude of A is compared with power of the output terminal of the RF-DC converter406, efficiency may be a. The efficiency a may be a ratio of the magnitude of input power (for example, PAI_IN) to the magnitude of output power (for example, PAI_OUT). Further, the second impedance matching circuit403may output power having the magnitude of B through impedance matching by the connection of the second switching element, efficiency may be b when the power having the magnitude of B is compared with power of the output terminal of the RF-DC converter406, and efficiency may be c when power having the magnitude of C is output. When power having the relatively stable magnitude is provided, the second impedance matching circuit403may perform impedance matching with relatively high efficiency. However, in an environment in which the magnitude of the input power or the frequency is changed, impedance matching may be performed with relatively low efficiency according to the change in efficiency by impedance matching of the second impedance matching circuit403, but impedance matching with maximum efficiency may be performed according to various embodiments even through the magnitude of the input power or the frequency is changed. To this end, the control circuit404may control in real time the second impedance matching circuit403to change the impedance value into the impedance value corresponding to the changed frequency on the basis of matching information learned for correlation of the impedance value which may cause maximum power in accordance with each frequency. As described above, the control circuit404may transfer a control signal for controlling the second impedance matching circuit403to the second impedance matching circuit403on the basis of matching information learned using the impedance matching network model. According to various embodiments, the energy harvesting circuit410may include the power detection circuit510for detecting power of the output terminal of the second impedance matching circuit403and the frequency detection circuit520for detecting the frequency of the output terminal of the second impedance matching circuit403. AlthoughFIG.4illustrates that the control circuit404detects the power and the frequency in the output terminal of the second impedance matching circuit403, the power detection circuit510and the frequency detection circuit520may be separately configured between the second impedance matching circuit403and the control circuit404independently from the control circuit404. According to various embodiments, the power detection circuit510may detect the magnitude of power between the output terminal of the second impedance matching circuit403and the input terminal of the RF-DC converter406. Further, the power detection circuit510may detect the magnitude of power (for example, PAI_OUT) in the output terminal of the RF-DC converter406. For example, the power detection circuit510may include a voltmeter capable of detecting the magnitude of the voltage (for example, PAI_IN) applied to the input terminal of the RF-DC converter406and the magnitude of the voltage (for example, PAI_OUT) in the output terminal of the RF-DC converter406, and the power detection circuit510may be implemented in various forms. Accordingly, information on the magnitude of the power, for example, the voltage detected by the power detection circuit510may be provided to the control circuit404. For example, the power detection circuit510may serve to find a value which may cause maximum power for the detected frequency (or input frequency) using a circuit for detecting a peak such as a peak detection circuit. According to various embodiments, the frequency detection circuit520may detect the frequency (for example, FAI) between the output terminal of the second impedance matching circuit403and the input terminal of the RF-DC converter406. For example, in the case of an RF input, the frequency is fast because of a frequency characteristic, and thus the frequency detection circuit520may divide the frequency through a 1/N divider and detect a frequency value. For example, the frequency detection circuit520may detect how many GHz the input frequency is. According to various embodiments, the control circuit404may be implemented using a Static Random-Access Memory (SRAM) array. For example, the control circuit404may be implemented using a 6T SRAM Cell. The control circuit404may include a power decoder531for decoding the magnitude of the voltage (for example, PAI_INT) applied to the input terminal of the RF-DC converter406and the magnitude of the voltage (for example, PAI_OUT) in the output terminal of the RF-DC converter406, detected by the power detection circuit510, and a frequency decoder532for decoding the frequency (for example, FAI) between the output terminal of the second impedance matching circuit403and the input terminal of the RF-DC converter406. The power decoder531may decode power information (for example, PAI_IN) in the input terminal of the RF-DC converter406in units determined per second in the detected frequency. Further, the power decoder531may decode power information (for example, PAI_OUT) in the output terminal of the RF-DC converter406in units determined per second in the detected frequency. In addition, the frequency decoder532also may decode the detected frequency in units determined per second. When learning for the impedance matching network model is completed, for example, when the magnitudes of power and the frequencies for power signals sequentially collected for all impedance combinations of the second impedance matching circuit403are detected and compared, and learning for the impedance value which may cause maximum power among the power signals is completed on the basis of the comparison result, a matching network driver533of the control circuit404may transfer a control signal (for example, CMN) for changing the impedance value of the second impedance matching circuit403to the learned impedance value corresponding to the detected frequency (for example, FAI) to the second impedance matching circuit403. When learning for the impedance matching network model is not completed, in order to find the impedance value which may cause the maximum power in accordance with the detected frequency (for example, FAI), the control circuit404may perform control to sequentially detect power and frequencies for all combinations of the second impedance matching circuit403. The control circuit404may perform control to selectively change impedance values of the second impedance matching circuit403in order to obtain the maximum output power during a learning mode. When the 6T SRAM Cell is used, the control circuit404operating as described above may be implemented as illustrated inFIG.6. FIG.6is a block diagram illustrating the control circuit404according to various embodiments. Referring toFIG.6, various switching combinations in the second impedance matching circuit403may be stored in the mapping form for the frequency using each memory cell (for example, 6T CELL), and the matching network driver533may find the impedance value which may cause the maximum power at a fast speed in accordance with the input frequency (or detected frequency). For example, the control circuit404may acquire information on the frequency detected by the frequency detection circuit520for the input RF input. There may be no impedance matching value pre-stored for the detected frequency (for example, frequency #1) at the beginning of learning, and thus the second impedance matching circuit403may be set to an initial state (for example, N=0) to find the impedance matching value which may cause the maximum power and then the operation of detecting the magnitude of the power for the power signal through the power detection circuit510may be performed. To this end, control signal #0 (for example CMN(0)) may be transferred to the second impedance matching circuit403, and the magnitude of power and the frequency for power signal #0 in the output terminal of the second impedance matching circuit403may be performed in accordance with control signal #0 (for example, CMN(0)). Accordingly, the magnitude of power for power signal #0 output through the power detection circuit510may be detected. Subsequently, the next control signal, for example, control signal #1 (for example, CMN(1)) may be transferred to the second impedance matching circuit403, and the magnitude of power and the frequency for power signal #1 in the output terminal of the second impedance matching circuit403may be detected in accordance with control signal #1 (for example, CMN(1)). Through the sequential scheme as described above, the last control signal, for example, control signal #N (for example, CMN(N)) may be transferred to the second impedance matching circuit403, and the magnitude of power and the frequency for power signal #N in the output terminal of the second impedance matching circuit403may be detected in accordance with control signal #N (for example, CMN(N)). As described above, when the operation of detecting the magnitude of power and the frequency is completed sequentially N+1 times (for example, 0 to N) for N switching combinations, a control signal which draws a power signal having the maximum power among power signals #0 to #N in accordance with the detected frequency may be stored as matching information corresponding to the detected frequency. For example, among all power signals, for example, power signal #0 to power signal #N, the maximum power signal may be identified, and a learning result having the impedance value which allows the maximum power signal among the plurality of impedance values to be output as the learned impedance value may be updated. The control signal may be a signal for controlling on/off of at least one switch of the second impedance matching circuit403and a combination of the switches to perform impedance matching with one of a plurality of impedance values. Accordingly, when there is matching information corresponding to the detected frequency, the control circuit404may provide the control signal (for example, CMN(N)) corresponding to the matching information to the second impedance matching circuit403, so that the second impedance matching circuit403may perform impedance matching for the next power signal with the impedance value changed according to the matching information. Therefore, the power signal having the maximum magnitude may be output from the output terminal of the second impedance matching circuit403. As described above, when the impedance value which allows the power signal having the maximum power to be output is acquired among the plurality of power signals #0 to #N, the learning result may be updated to correlate the control signal (for example, CMN(i)) corresponding to the impedance value with the detected frequency (for example, frequency #1). Further, in the learning mode, with respect to another frequency (for example, frequency #2), the learning result may be updated to correlate the control signal (for example, CMN(j)) corresponding to the impedance value for allowing the power signal having the maximum power to be output with the other frequency (for example, frequency #2). In such a way, it is possible to update the learning result to match the impedance value which may cause the maximum power with each frequency by repeating the same procedure while changing the configuration of the second impedance matching circuit403for each of a plurality of frequencies. FIG.7Ais a flowchart illustrating an example operation of an electronic device in an operation mode according to various embodiments.FIG.7Aillustrates the operation for performing an adaptive impedance matching method, and the operation method may include operations705to725. Each step/operation in the operation method may be performed by at least one of the electronic devices (for example, the electronic device150ofFIGS.1and2) or at least one processor of the electronic device (for example, the control circuit152ofFIG.1and the control circuit404ofFIG.4). In an embodiment, at least one of operations705to725may be omitted, the sequence of some operations may be changed, or other operations may be added. Hereinafter, the operation of the electronic device400is described by way of example. In operation705, for the wirelessly received power signal, the electronic device400may perform first impedance matching through the first impedance matching circuit402. In operation710, for the first impedance-matched power signal, the electronic device400may perform second impedance matching through the second impedance matching circuit403using one of a plurality of impedance values. The second impedance matching circuit403may include a plurality of circuits corresponding to the plurality of impedance values, and the plurality of circuits may include at least one capacitor and at least one switching element. When initial charging starts (or when wireless power is received), at least one capacitor may be connected to the output terminal of the first impedance matching circuit402and the input terminal of the power conversion circuit405(for example, RF-CD converter406) by the default value. In operation715, the electronic device400may determine whether the impedance matching network model is available. When the impedance matching network model is available, the electronic device400may perform control to change the impedance value of the second impedance matching circuit403into an impedance value learned using the impedance matching network model in accordance with power and the frequency of the second impedance-matched power signal in operation720. According to an embodiment, the impedance matching network model may be configured to sequentially acquire second impedance-matched power signals using the plurality of impedance values, identify a maximum power signal among the second impedance-matched power signals on the basis of comparison between powers of the second impedance-matched power signals, and change an impedance value of the second impedance matching circuit to the learned impedance value which is an impedance value corresponding to the maximum power signal among the plurality of impedance values. According to an embodiment, on the basis of detection of power and a frequency of another power signal output from the second impedance matching circuit, the impedance value learned using the impedance matching network model may include an impedance value causing maximum power of the other power signal for the detected frequency among the plurality of impedance values. In order to know values of the power and the frequency of the second impedance-matched power signal, detection for the magnitude of the power and a frequency value (or a frequency channel) may be performed by a power detection circuit or a frequency detection circuit. According to an embodiment, an input power between the output terminal of the second impedance matching circuit403and the input terminal of the power conversion circuit405and an output power in the output terminal of the power conversion circuit405may be detected. According to an embodiment, a frequency between the output terminal of the second impedance matching circuit403and the input terminal of the power conversion circuit405may be detected. When the impedance matching network model is available, the electronic device400may perform control to change the impedance value of the second impedance matching circuit403to the impedance value using the impedance matching network model in accordance with the power and the frequency of the second impedance-matched power signal in operation720. The operation of changing the impedance value of the second impedance matching circuit403may include an operation of controlling at least one switch for switching a short circuit of at least one capacitor included in the second impedance matching circuit403. For example, when matching information (for example, CMN(N)) is stored as matching information corresponding to the power (for example, PAI_IN(N)) and the frequency (for example, FAI(N)) of the second impedance-matched power signal, the pre-stored matching information (for example, CMN(N)) may correspond to the impedance matching value which may cause the maximum power for the frequency (for example, FAI(N)). Accordingly, if the frequency400is aware of the frequency (for example, FAI(N)) in the output terminal of the second impedance matching circuit403, the electronic device400may identify how to change the impedance value of the second impedance matching circuit403in accordance with the frequency. Accordingly, if the impedance value of the second impedance matching circuit403is changed on the basis of the learned matching information (for example, CMN(N)), a power signal having maximum power may be output from the output terminal of the second impedance matching circuit403thereafter. In operation725, the electronic device400may convert the second impedance-matched power signal in the AC form into power in the DC form for the battery408according to the changed impedance value. Since the impedance value for controlling the second impedance matching circuit403can be known at once on the basis of the learned matching information, maximum efficiency power, that is, maximum power through optimal impedance matching may be automatically acquired. Accordingly, the maximum efficiency power signal also may be output from the output terminal of the RF-DC converter406, and it is possible to acquire maximum efficiency in conversion into charging power for the battery408. As described above, if the second impedance matching circuit403is continuously controlled to have the impedance value causing the maximum power, it is possible to accurately acquire maximum power at a high speed. According to various embodiments, in subsequent charging, the learned matching information may be loaded and used for impedance matching directly without an additional tracking operation for impedance matching in the case of an input frequency corresponding to frequency stored in accordance with matching information, and thus energy harvesting may be performed with maximum efficiency for input power in a wide range and a total system efficiency may increase. Further, matching information learned through an update is used, and thus a time spent for finding an impedance matching value for maximum efficiency may be reduced. FIG.7Bis a flowchart illustrating example operation of an electronic device in a learning mode according to various embodiments.FIG.7Bis a drawing connected toFIG.7A, and “A” may be used to indicate the connection relation between operation715ofFIG.7Aand operation730ofFIG.7B.FIG.7Billustrates an advance preparation operation for learning matching information on the basis of detection information from the second impedance matching circuit403, for example, each of the frequency and the power magnitude, when the impedance matching network model is not available, and an operation method may include operations730to740. Each step/operation of the operation method may be performed in the learning mode. Referring toFIG.7B, when the impedance matching network model is not available in operation715ofFIG.7A, for example, when there is no matching information learned using the impedance matching network model in accordance with the power and the frequency of the second impedance-matched power signal, the electronic device400may detect power and a frequency of a power signal output from the second impedance matching circuit in operation730. In operation735, the electronic device400may determine whether detection of powers and frequencies of power signals according to all combinations of the second impedance matching circuit403is completed. For example, the operation of finding an impedance value which may cause maximum power among N combinations (or impedance values) of the second impedance matching circuit403may be repeatedly (or sequentially) performed for the detected frequencies and power magnitudes. As described above, the operation of monitoring values detected from output signals of the second impedance matching circuit403, learning matching information corresponding to the detected frequencies and power magnitudes on the basis of the monitoring result, and updating the matching information to matching information causing maximum power may be referred to as an operation of learning the impedance matching network model. In operation740, the electronic device400may acquire an impedance value causing maximum power of the power signal for the detected frequency among the plurality of impedance values and update the learning result. Accordingly, the updated learning result may be stored. For example, power signals according to a plurality of impedance values may be detected for the detected frequency, and the impedance matching network model may be updated such that an impedance value when a power signal having maximum power appears among the power signals may be correlated to the detected frequency. FIG.8is a diagram illustrating example operation of a power detection circuit and a frequency detection circuit according to various embodiments. Referring toFIG.8, since the frequency is high because of a frequency characteristic for an RF input, the frequency detection circuit520may divide the input frequency (for example, frequency #1 (Freq #1)) through a 1/N divider. In accordance with this, the power detection circuit510may detect powers having different magnitudes such as impedance matching value #1, impedance matching value #2, and impedance matching value #3 for frequency #1. As illustrated inFIG.8, in the case of impedance matching value #2 among impedance matching value #1, impedance matching value #2, and impedance matching value #3, power having the largest magnitude may be output. Accordingly, the learning result may be updated such that impedance matching value #2 generated when power having the largest magnitude among a plurality of powers detected by the power detection circuit510appears is correlated to matching information for frequency #1. As described above, the power detection circuit510may perform the operation of finding the impedance matching value making maximum power for the RF input appear. Accordingly, when the input frequency is received in the form of a frequency having the value of frequency #1, impedance matching value #2 stored in accordance with frequency #1 may be directly loaded and applied to control the second impedance matching circuit403, and thus optimal impedance matching at a high speed can be performed without a complex tracking process. Power of the power signal from the output terminal of the RF-DC converter406may be continuously detected and compared with the power signal from the output terminal of the second impedance matching circuit403. When the power signal has a difference larger than or equal to a threshold on the basis of the comparison with the power signal from the output terminal of the second impedance matching circuit403, an error in the RF-DC converter406may be detected. Alternatively, when the power signal from the output terminal of the RF-DC converter406is continuously detected and there is a difference larger than or equal to a threshold, the operation for finding other matching information may be performed. FIG.9is a circuit diagram403illustrating an example configuration of an adaptive impedance matching circuit according to various embodiments. According to various embodiments, the second impedance matching circuit403may include a plurality of circuits corresponding to a plurality of impedance values (for example, CMN(0), . . . , CMN(N)) as illustrated inFIG.9, and the plurality of circuits may be configured in parallel900, in series910, or by a combination thereof, and may be provided in other various forms.FIG.9illustrates a case in which capacitors are connected in series or in parallel, but is not limited thereto. For example, the second impedance matching circuit403may turn on/off at least some of the plurality of circuits in accordance with an impedance value according to a control signal of the control circuit404. According to various embodiments described above, impedance may be changed according to a change in a capacitance value of at least one capacitor within the second impedance matching circuit403. Accordingly, through a change in the connection of a capacitance value of a capacitor through a switching element based on a control signal, adaptive RF signal matching can be performed without addition of a separate element. FIG.10is a diagram illustrating an example of switching combinations for adaptive impedance matching according to various embodiments. FIG.10illustrates an example of available combinations in the second impedance matching circuit403. According to an embodiment, the control of adaptive impedance matching may be performed on the basis of a convolutional neural network. Since the convolutional neural network processes infinitely many combinations in parallel, a processing speed thereof may be 100 to 1000 times or more than the conventional series processing speed. Accordingly, the convolutional neural network scheme may be useful for rapidly finding an optimal value for various combinations which may be generated according to the series type, the parallel type, or a combination thereof for adaptive impedance matching. As described above, through the convolutional neural network scheme, input frequency information (for example, FAI) and power information (for example, PAI_INand PAI_OUT) may be configured in various combinations, and an impedance matching value (for example, one of CMX(0), . . . , CMX(N)) may be correlated to each combination. FIG.11is a flowchart1100illustrating an example operation of an electronic device according to various embodiments.FIG.11illustrates an example operation for performing an adaptive impedance matching method, and an operation method may include operations1105to1195. Each step/operation in the operation method may be performed by at least one of the electronic devices (for example, the electronic device150ofFIGS.1and2) or at least one processor of the electronic device (for example, the control circuit152ofFIG.1and the control circuit404ofFIG.4). In an embodiment, at least one of operations1105to1195may be omitted, the sequence of some operations may be changed, or other operations may be added. Hereinafter, the operation of the electronic device400is described by way of example. In operation1105, when power is initially turned on or charging is initially started, an impedance value of the second impedance matching circuit403may be configured as a default value by a control signal (for example, CMN). For example, an impedance value within the second impedance matching circuit403may be set as a default value. The operation of setting the default value may be referred to as an initialization operation. In operation1110, the electronic device400may select whether to operate in a learning mode for acquiring matching information for each frequency or an operation mode using learned matching information. For example, when an impedance matching network model using the learned matching information exists, it may be selected that the electronic device starts in the operation mode automatically or by a user selection. Accordingly, the electronic device400may determine whether to operate in the operation mode or the learning mode in operation1115. In the case of the operation mode, the electronic device400may detect a frequency in operation1120. In operation1125, the electronic device400may determine whether the detected frequency (for example, FAI) is between a minimum frequency (for example, Fmin) and a maximum frequency (for example, Fmax). For example, it may be determined whether the detected frequency is a normal frequency within an error range. If the detected frequency (for example, FAI) is between the minimum frequency (for example, Fmin) and the maximum frequency (for example, Fmax), the electronic device400may select a frequency channel in operation1130. For example, the electronic device may identify a frequency range which the detected frequency (for example, FAI) is in, and select an operation frequency range, that is, a frequency channel. In operation1135, the electronic device400may provide a control signal (for example, CMN(FAI)) corresponding to the detected frequency (for example, FAT) to the second impedance matching circuit403. Since the impedance value is changed in accordance with the control signal (for example, CMN(FAI), the next power signal may be adjusted to have maximum power and output from the output terminal of the second impedance matching circuit403. Accordingly, in operation1140, the electronic device400may continuously monitor power (for example, PAI_IN) and the frequency (for example, FAI) in the output terminal of the second impedance matching circuit403and power (for example, PAI_OUT) in the output terminal of the RF-DC converter406. In operation1145, when the frequency (for example, FAI) in the output terminal of the second impedance matching circuit403is changed on the basis of the monitoring result in operation1145, operations1125to1145for finding the matching information corresponding to the changed frequency in operation1120and changing impedance matching may be repeatedly performed. As described above, the electronic device400may continuously (or sequentially) monitor the input frequency, the input power, and the output power and, when the frequency is changed or the output power is rapidly reduced, may perform an operation of loading again the control signal causing maximum power by returning to the operation of changing the control signal (CMN) to the default value and detecting the frequency once again. In the case of the learning mode, the electronic device400may detect the frequency in operation1150. Since operations1150to1160are the same as or similar to operations1120to1130in the learning mode, a detailed description thereof may not be repeated. However, in operation1160, the value for the frequency channel may be primarily set (e.g., allocated) in the learning mode. For example, the control signal may be configured as the value of CMN(0) for the input frequency (for example, Freq #1). Subsequently, in operation1165, the electronic device400may detect power (for example, PAI_IN(n)) in the output terminal of the second impedance matching circuit403. In operation1170, it may be determined whether power (for example, for PAI_IN(n)) in the output terminal of the second impedance matching circuit403is larger than previous power (PAI_IN(n−1)). When the power is larger than the previous power, the power and current control signal may be maintained in operation1175. When the power is not larger than the previous power (PAI_IN(n−1)), it may be determined whether the current control signal (for example, CMN(n)) is smaller than a maximum control signal (for example, CMN(max)) in operation1180. Operation1180may be an operation for determining whether the process of comparing the power magnitudes for all switching combinations is completed. When the current control signal (for example, CMN(n)) is smaller than the maximum control signal (for example CMN(max)), the value of the current control signal (for example, CMN(n)) may be increased to compare the power magnitude corresponding to the next impedance value in operation1185. Accordingly, the control signal, that is, the impedance value may be sequentially changed one by one. As described above, the impedance value may be changed until the series type, the parallel type, or a combination thereof for the second impedance matching circuit403are all satisfied. Thereafter, when the current control signal (for example, CMN(n)) is not smaller than the maximum control signal (for example, CMN(max) in operation1180, that is, when the power magnitude comparison operation for all switch combinations is performed, the electronic device400may update the learning result by correlating the detected frequency (for example, FAI), the detected power (for example, PAI_IN(n)), and the control signal (or impedance value) (for example, CMN(n)) for the current frequency channel in operation1190. For example, the impedance value which may cause the maximum power for the detected frequency may be correlated to correspond to the control signal to be applied to the second impedance matching circuit403. On the basis of the learning result, the impedance matching value and the optimal values for the corresponding power and frequency may be learned, and the learning mode may end in accordance with the completion of storage in operation1195. FIG.12is a diagram illustrating example images for a matching point changed through adaptive impedance matching according to various embodiments. According to various embodiments, it may be noted through simulation that S11(refer toFIG.13) can move to a point corresponding to an optimal point as illustrated inFIG.12when impedance matching is performed. When a point value at a starting point A is initially S11as indicated by reference numeral1205, the point A may move to a point B along the circle if a series capacitance value increases from1210to1225on the basis of the point value. Further, when a parallel capacitance value increases at the point B, the point value may reach a final matching point C along the circle. FIG.13is a graph illustrating an example frequency characteristic according to adaptive impedance matching according to various embodiments. FIG.13illustrates a frequency characteristic when an impedance matching value which may cause maximum power is found in power signals in a band of 5.8 GHz corresponding to a wireless power reception frequency.FIG.13shows a characteristic when a value of S11corresponding to a reflection coefficient is changed to a log scale in each matching point ofFIG.12. The reflection coefficient of S11in the case in which impedance matching is performed at the central point of a Smith chart is lowest as indicated by reference number1310, and it may be noted that the largest power for an input is applied to the corresponding part. The electronic device according to various embodiments may be one of various types of electronic devices. The electronic devices may include, for example, a portable communication device (e.g., a smart phone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, a home appliance, or the like. The electronic device according to embodiments of the disclosure is not limited to those described above. It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, and/or alternatives for a corresponding embodiment. With regard to the description of the drawings, similar reference numerals may be used to designate similar or relevant elements. It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise. As used herein, each of such phrases as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C,” may include all possible combinations of the items enumerated together in a corresponding one of the phrases. As used herein, such terms as “a first”, “a second”, “the first”, and “the second” may be used to simply distinguish a corresponding element from another, and does not limit the elements in other aspect (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element. As used herein, the term “module” may include a unit implemented in hardware, software, or firmware, or any combination thereof, and may be interchangeably used with other terms, for example, “logic,” “logic block,” “component,” or “circuit”. The “module” may be a minimum unit of a single integrated component adapted to perform one or more functions, or a part thereof. For example, according to an embodiment, the “module” may be implemented in the form of an application-specific integrated circuit (ASIC). Various embodiments as set forth herein may be implemented as software (e.g., the program140) including one or more instructions that are stored in a storage medium (e.g., the internal memory136or external memory138) that is readable by a machine (e.g., the electronic device101). For example, a processor (e.g., the processor120) of the machine (e.g., the electronic device101) may invoke at least one of the one or more instructions stored in the storage medium, and execute it, with or without using one or more other components under the control of the processor. This allows the machine to be operated to perform at least one function according to the at least one instruction invoked. The one or more instructions may include a code generated by a complier or a code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Wherein, the “non-transitory” storage medium is a tangible device, and may not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. According to an embodiment, a method according to various embodiments of the disclosure may be included and provided in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., Play Store™), or between two user devices (e.g., smart phones) directly. If distributed online, at least part of the computer program product may be temporarily generated or at least temporarily stored in the machine-readable storage medium, such as memory of the manufacturer's server, a server of the application store, or a relay server. According to various embodiments, each element (e.g., a module or a program) of the above-described elements may include a single entity or multiple entities. According to various embodiments, one or more of the above-described elements may be omitted, or one or more other elements may be added. Alternatively or additionally, a plurality of elements (e.g., modules or programs) may be integrated into a single element. In such a case, according to various embodiments, the integrated element may still perform one or more functions of each of the plurality of elements in the same or similar manner as they are performed by a corresponding one of the plurality of elements before the integration. According to various embodiments, operations performed by the module, the program, or another element may be carried out sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order or omitted, or one or more other operations may be added. According to various embodiments, a storage medium storing instructions is provided. The instructions are configured to cause at least one circuit to perform at least one operation when executed by the at least one circuit. The at least one operation may performing second impedance matching on the first impedance-matched power signal through a second impedance matching circuit using one of a plurality of impedance values, performing control to change an impedance value of the second impedance matching circuit to an impedance value learned using an impedance matching network model in accordance with a power and a frequency of the second impedance-matched power signal, and converting a second impedance-matched power signal in an AC form to a charging power for a battery according to the changed impedance value. The various example embodiments of the disclosure described and shown in the disclosure and the drawings have been presented to explain the technical contents of the disclosure and help understanding of the disclosure, and are not intended to limit the scope of embodiments of the disclosure. Therefore, the scope of the disclosure should be understood to include, in addition to the embodiments disclosed herein, all changes and modifications derived on the basis of the technical idea of the disclosure. | 86,814 |
11862996 | DETAILED DESCRIPTION Certain embodiments of the present invention relate to half bridge power conversion circuits that employ one or more gallium nitride (GaN) devices. While the present invention can be useful for a wide variety of half bridge circuits, some embodiments of the invention are particularly useful for half bridge circuits designed to operate at high frequencies and/or high efficiencies with integrated driver circuits, integrated level shift circuits, integrated bootstrap capacitor charging circuits, integrated startup circuits and/or hybrid solutions using GaN and silicon devices, as described in more detail below. Half Bridge Circuit #1 Now referring toFIG.1, in some embodiments circuit100may include a pair of complementary power transistors (also referred to herein as switches) that are controlled by one or more control circuits configured to regulate power delivered to a load. In some embodiments a high side power transistor is disposed on a high side device along with a portion of the control circuit and a low side power transistor is disposed on a low side device along with a portion of the control circuit, as described in more detail below. The integrated half bridge power conversion circuit100illustrated inFIG.1includes a low side GaN device103, a high side GaN device105a load107, a bootstrap capacitor110and other circuit elements, as illustrated and discussed in more detail below. Some embodiments may also have an external controller (not shown inFIG.1) providing one or more inputs to circuit100to regulate the operation of the circuit. Circuit100is for illustrative purposes only and other variants and configurations are within the scope of this disclosure. In one embodiment, low side GaN device103may have a GaN-based low side circuit104that includes a low side power transistor115having a low side control gate117. Low side circuit104may further include an integrated low side transistor driver120having an output123connected to low side transistor control gate117. In another embodiment high, side GaN device105may have a GaN-based high side circuit106that includes a high side power transistor125having a high side control gate127. High side circuit106may further include an integrated high side transistor driver130having an output133connected to high side transistor control gate127. A voltage source135(also known as a rail voltage) may be connected to a drain137of high side transistor125, and the high side transistor may be used to control power input into power conversion circuit100. High side transistor125may further have a source140that is coupled to a drain143of low side transistor115, forming a switch node145. Low side transistor115may have a source147connected to ground. In one embodiment, low side transistor115and high side transistor125may be GaN-based enhancement-mode field effect transistors. In other embodiments low side transistor115and high side transistor125may be any other type of device including, but not limited to, GaN-based depletion-mode transistors, GaN-based depletion-mode transistors connected in series with silicon based enhancement-mode field-effect transistors having the gate of the depletion-mode transistor connected to the source of the silicon-based enhancement-mode transistor, silicon carbide based transistors or silicon-based transistors. In some embodiments high side device105and low side device103may be made from a GaN-based material. In one embodiment the GaN-based material may include a layer of GaN on a layer of silicon. In further embodiments the GaN based material may include, but not limited to, a layer of GaN on a layer of silicon carbide, sapphire or aluminum nitride. In one embodiment the GaN based layer may include, but not limited to, a composite stack of other III nitrides such as aluminum nitride and indium nitride and III nitride alloys such as AlGaN and InGaN. In further embodiments, GaN-based low side circuit104and GaN-based high side circuit106may be disposed on a monolithic GaN-based device. In other embodiments GaN-based low side circuit104may be disposed on a first GaN-based device and GaN-based high side circuit106may be disposed on a second GaN-based device. In yet further embodiments GaN-based low side circuit104and GaN-based high side circuit106may be disposed on more than two GaN-based devices. In one embodiment, GaN-based low side circuit104and GaN-based high side circuit106may contain any number of active or passive circuit elements arranged in any configuration. Low Side Device Low side device103may include numerous circuits used for the control and operation of the low side device and high side device105. In some embodiments, low side device103may include logic, control and level shift circuits (low side control circuit)150that controls the switching of low side transistor115and high side transistor125along with other functions, as discussed in more detail below. Low side device103may also include a startup circuit155, a bootstrap capacitor charging circuit157and a shield capacitor160, as also discussed in more detail below. Now referring toFIG.2, the circuits within low side control circuit150are functionally illustrated. Each circuit within low side control circuit150is discussed below, and in some cases is shown in more detail inFIGS.3-14. In one embodiment the primary function of low side control circuit150may be to receive one or more input signals, such as a PWM signal from a controller, and control the operation of low side transistor115, and high side transistor125. In one embodiment, first and a second level shift transistors203,205, respectively, may be employed to communicate with high side logic and control circuit153(seeFIG.1). In some embodiments, first level shift transistor203may be a high voltage enhancement-mode GaN transistor. In further embodiments, first level shift transistor203may be similar to low side transistor115(seeFIG.1) and high side transistor125, except it may be much smaller in size (e.g., first level shift transistor may be tens of microns in gate width with minimum channel length). In other embodiments first level shift transistor203may experience high voltage and high current at the same time (i.e. the device may operate at the high power portion of the device Safe Operating Area) for as long as high side transistor125(seeFIG.1) is on. Such conditions may cause relatively high power dissipation, thus some embodiments may involve design and device reliability considerations in the design of first level shift transistor203, as discussed in more detail below. In further embodiments, a first level shift resistor207may be added in series with a source210of first level shift transistor203to limit gate213to source210voltage and consequently the maximum current through the first level shift transistor. Other methods may be employed to limit the current through first level shift transistor203, and are within the scope of this disclosure. Drain215of first level shift transistor203may be coupled to high side logic and control circuit153(seeFIG.1), as discussed in more detail below. In one embodiment, first level shift transistor203may comprise a portion of an inverter circuit having a first input and a first output and configured to receive a first input logic signal at the first input terminal and in response, provide a first inverted output logic signal at the first output terminal, as discussed in more detail below. In further embodiments the first input and the first inverted output logic signals can be referenced to different voltage potentials. In some embodiments, first level shift resistor207may be capable of operating with the first inverted output logic signal referenced to a voltage that is more than 13 volts higher than a reference voltage for the first input logic signal. In other embodiments it may be capable of operating with the first inverted output logic signal referenced to a voltage that is more than 20 volts higher than a reference voltage for the first input logic signal, while in other embodiments it may be between 80-400 volts higher. In other embodiments, first level shift resistor207may be replaced by any form of a current sink. For example, in one embodiment, source210of first level shift transistor203may be connected to a gate to source shorted depletion-mode device. In a further embodiment, the depletion-mode device may be fabricated by replacing the enhancement-mode gate stack with a high voltage field plate metal superimposed on top of the field dielectric layers. The thickness of the field dielectric and the work function of the metal may be used to determine the pinch-off voltage of the stack. In other embodiments first level shift resistor207may be replaced by a current sink. The current sink may use a reference current (Iref) that may be generated by startup circuit155(illustrated inFIG.1and discussed in more detail below). Both the depletion-mode transistor and current sink embodiments may result in a significant device area reduction compared to the resistor embodiment (i.e., because a relatively small depletion-mode transistor would suffice and Iref is already available from startup circuit155). Second level shift transistor205may be designed similar to first level shift transistor203(e.g., in terms of voltage capability, current handling capability, thermal resistance, etc.). Second level shift transistor205may also be built with either an active current sink or a resistor, similar to first level shift transistor203. In one embodiment the primary difference with second level shift transistor205may be in its operation. In some embodiments the primary purpose of second level shift transistor205may be to prevent false triggering of high side transistor125(seeFIG.1) when low side transistor115turns off. In one embodiment, for example, false triggering can occur in a boost operation when low side transistor115turn off results in the load current flowing through high side transistor125while the transistor is operating in the third quadrant with its gate shorted to its source (i.e., in synchronous rectification mode). This condition may introduce a dv/dt condition at switch node (Vsw)145since the switch node was at a voltage close to ground when low side transistor115was on and then transitions to rail voltage135over a relatively short time period. The resultant parasitic C*dv/dt current (i.e., where C=Coss of first level shift transistor203plus any other capacitance to ground) can cause first level shift node305(seeFIG.3) to get pulled low which will then turn on high side transistor125. In some embodiments this condition may not be desirable because there may be no dead time control, and shoot through may occur from high side transistor125and low side transistor115being in a conductive state simultaneously. FIG.3illustrates one embodiment showing how first level shift transistor203may be electrically coupled to high side device105. First level shift transistor203, located on low side device103, is illustrated along with a pull up resistor303that may be located on high side device105(seeFIG.1). In some embodiments, first level shift transistor203may operate as a pull down transistor in a resistor pull up inverter. In further embodiments, when level shift driver circuit217(seeFIG.2) supplies a high gate signal (L1_DR) to first level shift transistor203, a first level shift node305gets pulled low which is inverted by high side logic and control circuit153(seeFIG.1). The inverted signal appears as a high state signal that turns on high side transistor137(seeFIG.1) which then pulls the voltage at switch node (Vsw)145close to rail voltage135. Conversely, when level shift driver circuit217(seeFIG.2) supplies a low gate signal to first level shift transistor203, a first level shift node305gets pulled to a high logic state which is inverted by high side logic and control circuit153(seeFIG.1). The inverted signal appears as a low logic state signal that turns off high side transistor125. This scheme may result in a non-inverted gate signal to high side transistor125. In further embodiments, first level shift transistor203may be designed large enough to be able to pull down on first level shift node305, but not so large that its drain to source and drain to substrate (i.e., the semiconductor substrate) capacitances induce false triggering of high side logic and control circuit153. In some embodiments pull up resistor303may instead be an enhancement-mode transistor, a depletion-mode transistor or a reference current source element. In further embodiments pull up resistor303may be coupled between the drain and the positive terminal of a floating supply (e.g., a bootstrap capacitor, discussed in more detail below) that is referenced to a different voltage rail than ground. In yet further embodiments there may be a first capacitance between the first output terminal (LS NODE)305and switch node (Vsw)145(seeFIG.1) and a second capacitance between the first output terminal and ground, where the first capacitance is greater than the second capacitance. The first capacitance may be designed such that in response to a high dv/dt signal at switch node (Vsw)145(seeFIG.1), a large portion of the C*dv/dt current is allowed to conduct through the first capacitance ensuring that the voltage at first output terminal305tracks the voltage at the switch node (Vsw). In some embodiments shield capacitor160(seeFIG.1) may be designed to act as the first capacitor as described above. In further embodiments shield capacitor160(seeFIG.1) may be used to create capacitance between first output terminal305and switch node (Vsw)145(seeFIG.1) in half bridge power conversion circuit100. In yet further embodiments, shield capacitor160(seeFIG.1) may also be used to minimize a capacitance between first output terminal305and substrate (i.e., the semiconductor substrate). More specifically, in some embodiments shield capacitor160may be created by adding a conductive shield layer to the device and coupling the layer to switch node (Vsw)145. This structure may effectively create two capacitors. One capacitor is coupled between output terminal305and switch node (Vsw)145, and the other is coupled between the switch node and the substrate. The capacitance between output terminal305and the substrate is thereby practically eliminated. In further embodiments shield capacitor160(seeFIG.1) may be constructed on the low side chip103. Logic, control and level shifting circuit150(seeFIG.2) may have other functions and circuits such as, but not limited to, a level shift driver circuit217, a low side transistor drive circuit120, a blanking pulse generator223, a bootstrap transistor drive circuit225and an under voltage lock out (UVLO) circuit227, as explained in separate figures with more detail below. Now referring toFIG.4, level shift driver circuit217is shown in greater detail. In one embodiment level shift driver circuit217may include a first inverter405and a second inverter410in a sequential chain. In further embodiments, since level shift driver circuit217may be driving a small gate width first level shift transistor203, there may be no need for a buffer stage. In one embodiment, level shift driver circuit217is driven directly by the pulse-width modulated high side signal (PWM_HS) from the controller (not shown). In some embodiments the (PWM_HS) signal may be supplied by an external control circuit. In one embodiment the external control circuit may be an external controller that is in the same package with high side device105, low side device103, both devices, or packaged on its own. In further embodiments, level shift driver circuit217may also include logic that controls when the level shift driver circuit communicates with first level shift transistor203(seeFIG.3). In one embodiment an optional low side under voltage lock out signal (LS_UVLO) may be generated by an under voltage lock out circuit within level shift driver circuit217. The low side under voltage lock out circuit can be used to turn off level shift driver circuit217if either (Vcc) or (Vdd) for the low side (Vdd_LS) go below a certain reference voltage, or a fraction of the reference voltage. In further embodiments level shift driver circuit217may generate a shoot through protection signal for the low side transistor (STP_LS) that is used to prevent shoot through arising from overlapping gate signals on low side transistor115and high side transistor125. The function of the (STP_LS) signal may be to ensure that low side driver circuit120(seeFIG.2) only communicates with the gate terminal of the low side transistor115when the gate signal to high side transistor125is low. In other embodiments, the output of first inverter405may be used to generate the shoot through protection signal (STP_LS) for the low side transistor115. In further embodiments, logic for UVLO and shoot-through protection may implemented by adding a multiple input NAND gate to first inverter405, where the inputs to the NAND gate are the (PWM_HS), (LS_UVLO) and (STP_HS) signals. In yet further embodiments, first inverter405may only respond to the (PWM_HS) signal if both (STP_HS) and (LS_UVLO) signals are high. In further embodiments, the STP_HS signal may be generated from the low side gate driver block120, as explained in separate figures with more detail. Now referring toFIG.5, blanking pulse generator223may be used to generate a pulse signal that corresponds to the turn off transient of low side transistor115. This pulse signal may then turn on second level shift transistor205for the duration of the pulse, which triggers a control circuit on high side device105(seeFIG.1) to prevent false pull down of first level shift node305voltage. FIG.5illustrates a schematic of one embodiment of blanking pulse generator223. In some embodiments a low side transistor115gate signal (LS_GATE) is fed as an input to blanking pulse generator223. The (LS_GATE) signal is inverted by a first stage inverter505, then sent through an RC pulse generator510to generate a positive pulse. In some embodiments an inverted signal may be needed because the pulse corresponds to the falling edge of the (LS_GATE) signal. A capacitor515in RC pulse generator510circuit may be used as a high pass filter allowing the dv/dt at its input to appear across resistor520. Once the dv/dt vanishes at the input to the RC pulse generator510, capacitor515may charge slowly through resistor520, resulting in a slow decaying voltage waveform across the resistor. The pulse may then be sent through a second inverter525, a third inverter530and a buffer535to generate a square wave pulse for the blanking pulse (B_PULSE) signal. The duration of the pulse may be determined by the value of capacitor515and resistor520in RC pulse generator510. In some embodiments, capacitor515may be constructed using a drain to source shorted enhancement-mode GaN transistor. Now referring toFIG.6, example waveforms600within blanking pulse generator223are illustrated for one embodiment. Trace605shows a falling edge of the low side gate pulse (LS_GATE). Trace610shows the rising edge of first stage inverter505output. Trace615shows the output of RC pulse generator510and trace620shows the resulting blanking pulse (B_PULSE) signal that is an output of blanking pulse generator223. Now referring toFIG.7, bootstrap transistor drive circuit225is illustrated in greater detail. Bootstrap transistor drive circuit225includes inverter730, first buffer735and second buffer745. Bootstrap transistor drive circuit225may receive the (BOOTFET_DR_IN) signal from low side driver circuit120. The (BOOTFET_DR_IN) signal may be inverted with respect to the LS_GATE signal. Bootstrap transistor drive circuit225may be configured to provide a gate drive signal called (BOOTFET_DR) to a bootstrap transistor in bootstrap charging circuit157(seeFIG.1), discussed in more detail below. The (BOOTFET_DR) gate drive signal may be timed to turn on the bootstrap transistor when low side transistor115is turned on. Also, since bootstrap transistor drive circuit225is driven by (Vcc), the output of this circuit may have a voltage that goes from 0 volts in a low state to (Vcc)+6 volts in a high state. In one embodiment the bootstrap transistor is turned on after low side transistor115is turned on, and the bootstrap transistor is turned off before the low side transistor is turned off. In some embodiments, the turn on transient of the (BOOTFET_DR) signal may be delayed by the introduction of a series delay resistor705to the input of second buffer745, that may be a gate of a transistor in a final buffer stage. In further embodiments, the turn off transient of low side transistor115(seeFIG.1) may be delayed by the addition of a series resistor to a gate of a final pull down transistor in low side drive circuit120. In one embodiment, one or more capacitors may be used in bootstrap transistor drive circuit225, and support voltages of the order of (Vcc) which, for example, could be 20 volts, depending on the end user requirements and the design of the circuit. In some embodiments the one or more capacitors may be made with a field dielectric to GaN capacitor instead of a drain to source shorted enhancement-mode transistor. Now referring toFIG.8a block diagram for low side transistor drive circuit120is illustrated. Low side transistor drive circuit120may have a first inverter805, a buffer810, a second inverter815, a second buffer820and a third buffer825. Third buffer825may provide the (LS_GATE) signal to low side transistor115(seeFIG.1). In some embodiments two inverter/buffer stages may be used because the input to the gate of low side transistor115(seeFIG.1) may be synchronous with (Vin). Thus, (Vin) in a high state may correspond to (Vgate) of low side transistor115in a high state and vice versa. In further embodiments, certain portions of low side drive circuit120may have an asymmetric hysteresis. Some embodiments may include asymmetric hysteresis using a resistor divider840with a transistor pull down850. Further embodiments may have multiple input NAND gates for the (STP_LS) signal (shoot through protection on low side transistor115). In one embodiment, low side drive circuit120may receive the shoot through protection signal (STP_LS) from level shift driver circuit217. The purpose of the (STP_LS) signal may be similar to the (STP_HS) signal described previously. The (STP_LS) signal may ensure that low side transistor drive circuit120does not communicate with gate117(seeFIG.1) of low side transistor115when level shift driver circuit217output is at a high state. In other embodiments, the output of the first inverter stage805may be used as the (STP_HS) signal for level shift drive circuit217and the (BOOTFET_DR_IN) signal for bootstrap transistor drive circuit225. In some embodiments, low side transistor drive circuit120may employ multiple input NAND gates for the (LS_UVLO) signal received from UVLO circuit227(seeFIG.2). Further embodiments may employ a turn off delay resistor that may be in series with a gate of a final pull down transistor in final buffer stage825. The delay resistor may be used in some embodiments to make sure the bootstrap transistor is turned off before low side transistor115turns off. Now referring toFIG.9, startup circuit155is illustrated in greater detail. Startup circuit155may be designed to have a multitude of functionalities as discussed in more detail below. Primarily, startup circuit155may be used to provide an internal voltage (in this case START_Vcc) and provide enough current to support the circuits that are being driven by (Vcc). This voltage may remain on to support the circuits until (Vcc) is charged up to the required voltage externally from rail voltage135(V+). Startup circuit155may also provide a reference voltage (Vref) that may be independent of the startup voltage, and a reference current sink (Iref). In one embodiment, a depletion-mode transistor905may act as the primary current source in the circuit. In further embodiments depletion-mode transistor905may be formed by a metal layer disposed over a passivation layer. In some embodiments, depletion-mode transistor905may use a high voltage field plate (typically intrinsic to any high-voltage GaN technology) as the gate metal. In further embodiments a field dielectric may act as the gate insulator. The resultant gated transistor may be a depletion-mode device with a high channel pinch-off voltage (Vpinch) (i.e., pinch-off voltage is proportional to the field dielectric thickness). Depletion-mode transistor905may be designed to block relatively high voltages between its drain (connected to V+) and its source. Such a connection may be known as a source follower connection. Depletion-mode transistor905may have a gate906coupled to ground, a source907coupled to a first node911and a drain909coupled to voltage source135. In further embodiments a series of identical diode connected enhancement-mode low-voltage transistors910may be in series with depletion-mode transistor905. Series of identical diode connected enhancement-mode low-voltage transistors910may be connected in series between a first node911and a second node912. One or more intermediate nodes913may be disposed between each of series of identical diode connected enhancement-mode low-voltage transistors910. The width to length ratio of the transistors may set the current drawn from (V+) as well as the voltage across each diode. To remove threshold voltage and process variation sensitivity, series of identical diode connected enhancement-mode low-voltage transistors910may be designed as large channel length devices. In some embodiments, series of identical diode connected enhancement-mode low-voltage transistors910may be replaced with one or more high value resistors. In further embodiments, at the bottom end of series of identical diode connected enhancement-mode low-voltage transistors910, a current mirror915may be constructed from two enhancement-mode low-voltage transistors and used to generate a reference current sink (Iref). First current mirror transistor920may be diode connected and second current mirror transistor925may have a gate connected to the gate of the first current mirror transistor. The sources of first and second current mirror transistors920,925, respectively may be coupled and tied to ground. A drain terminal of first current mirror transistor920may be coupled to second junction912and a source terminal of second current mirror transistor925may be used as a current sink terminal. This stack of current mirror915and series of identical diode connected enhancement-mode low-voltage transistors910may form what is known as a “source follower load” to depletion-mode transistor905. In other embodiments, when gate906of depletion-mode transistor905is tied to ground, source907of the depletion-mode transistor may assume a voltage close to (Vpinch) when current is supplied to the “source follower load”. At the same time the voltage drop across diode connected transistor920in current mirror915may be close to the threshold voltage of the transistor (Vth). This condition implies that the voltage drop across each of series of identical diode connected enhancement-mode low-voltage transistors910may be equal to (Vpinch−Vth)/n where ‘n’ is the number of diode connected enhancement-mode transistors between current mirror915and depletion-mode transistor905. For example, if the gate of a startup transistor930is connected to the third identical diode connected enhancement-mode low-voltage transistor from the bottom, the gate voltage of the startup transistor may be 3*(Vpinch−Vth)/n+Vth. Therefore, the startup voltage may be 3*(Vpinch−Vth)/n+Vth−Vth=3*(Vpinch−Vth)/n. As a more specific example, in one embodiment where (Vpinch)=40 volts, (Vth)=2 volts where n=6 and (Vstartup)=19 volts. In other embodiments, startup circuit155may generate a reference voltage signal (Vref). In one embodiment, the circuit that generates (Vref) may be similar to the startup voltage generation circuit discussed above. A reference voltage transistor955may be connected between two transistors in series of identical diode connected enhancement-mode low-voltage transistors910. In one embodiment (Vref)=(Vpinch−Vth)/n. In further embodiments, a disable pull down transistor935may be connected across the gate to source of startup transistor930. When the disable signal is high, startup transistor930will be disabled. A pull down resistor940may be connected to the gate of disable transistor935to prevent false turn on of the disable transistor. In other embodiments a diode clamp945may be connected between the gate and the source terminals of startup transistor930to ensure that the gate to source voltage capabilities of the startup transistor are not violated during circuit operation (i.e., configured as gate overvoltage protection devices). In some embodiments, diode clamp945may be made with a series of diode connected GaN-based enhancement-mode transistors1050, as illustrated inFIG.10. Now referring toFIG.11, UVLO circuit227is illustrated in greater detail. In some embodiments, UVLO circuit227may have a differential comparator1105, a down level shifter1110and an inverter1115. In further embodiments, UVLO circuit227may use (Vref) and (Iref) generated by startup circuit155(seeFIG.9) in a differential comparator/down level shifter circuit to generate the (LS_UVLO) signal that feeds into level shift driver circuit217(seeFIG.2) and low side transistor driver circuit120. In some embodiments UVLO circuit227can also be designed to have asymmetric hysteresis. In further embodiments the output of UVLO circuit227may be independent of threshold voltage. This may be accomplished by choosing a differential comparator with a relatively high gain. In one embodiment the gain can be increased by increasing the value of the current source and the pull up resistors in the differential comparator. In some embodiments the limit on the current and resistor may be set by (Vref). In other embodiments voltages (VA) and (VB),1120and1125, respectively, may be proportional to (Vcc) or (Vdd_LS) and (Vref) as dictated by the resistor divider ratio on each input. When (VA)1120>(VB)1125the output of the inverting terminal goes to a low state. In one specific embodiment, the low state=(Vth) since the current source creates a source follower configuration. Similarly when (VA)1120<(VB)1125the output goes to a high state (Vref). In some embodiments down level shifter1110may be needed because the low voltage needs to be shifted down by one threshold voltage to ensure that the low input to the next stage is below (Vth). The down shifted output may be inverted by a simple resistor pull up inverter1115. The output of inverter1115is the (LS_UVLO) signal. Now referring toFIG.12, bootstrap capacitor charging circuit157is illustrated in greater detail. In one embodiment, bootstrap diode and transistor circuit157may include a parallel connection of a high voltage diode connected enhancement-mode transistor1205and a high voltage bootstrap transistor1210. In further embodiments, high voltage diode connected enhancement-mode transistor1205and high voltage bootstrap transistor1210can be designed to share the same drain finger. In some embodiments the (BOOTFET_DR) signal may be derived from bootstrap transistor drive circuit225(seeFIG.2). As discussed above, high voltage bootstrap transistor1210may be turned on coincident with the turn on of low side transistor115(seeFIG.1). Now referring toFIG.13, an alternative bootstrap diode and transistor circuit1300may be used in place of bootstrap diode and transistor circuit157discussed above inFIG.12. In the embodiment illustrated inFIG.13, a depletion-mode device1305cascoded by an enhancement-mode low voltage GaN device1310may be connected as illustrated in schematic1300. In another embodiment, a gate of depletion-mode device1305can be connected to ground to reduce the voltage stress on cascoded enhancement-mode device1310, depending upon the pinch-off voltage of the depletion-mode device. High Side Device Now referring toFIG.14, high side logic and control circuit153is illustrated in greater detail. In one embodiment, high side driver130receives inputs from first level shift receiver1410and high side UVLO circuit1415and sends a (HS_GATE) signal to high side transistor125(seeFIG.1). In yet further embodiments, a pull up trigger circuit1425is configured to receive the (LSHIFT_1) signal and control pull up transistor1435. In some embodiments, second level shift receiver circuit1420is configured to control blanking transistor1440. Both the pull up transistor1435and blanking transistor1440may be connected in parallel with pull up resistor1430. Each circuit within high side logic and control circuit153is discussed below, and in some cases is shown in more detail inFIGS.16-20. Now referring toFIG.15, first level shift receiver1410is illustrated in greater detail. In some embodiments, first level shift receiver1410may convert the (L_SHIFT1) signal to an (LS_HSG) signal that can be processed by high side transistor driver130(seeFIG.14) to drive high side transistor125(seeFIG.1). In further embodiments, first level shift receiver1410may have three enhancement-mode transistors1505,1510,1515employed in a multiple level down shifter and a plurality of diode connected transistors1520acting as a diode clamp, as discussed in more detail below. In one embodiment, first level shift receiver1410may down shift the (L_SHIFT1) signal by 3*Vth (e.g., each enhancement-mode transistor1505,1510,1515may have a gate to source voltage close to Vth). In some embodiments the last source follower transistor (e.g., in this case transistor1515) may have a three diode connected transistor clamp1520across its gate to source. In further embodiments this arrangement may be used because its source voltage can only be as high as (Vdd_HS) (i.e., because its drain is connected to Vdd_HS) while its gate voltage can be as high as V (L_SHIFT1)−2*Vth. Thus, in some embodiments the maximum gate to source voltage on last source follower transistor1515may be greater than the maximum rated gate to source voltage of the device technology. The output of final source follower transistor1515is the input to high side transistor drive130(seeFIG.1), (i.e., the output is the LS_HSG signal). In further embodiments fewer or more than three source follower transistors may be used. In yet further embodiments, fewer or more than three diode connected transistors may be used in clamp1520. Now referring toFIG.16, second level shift receiver1420is illustrated in greater detail. In one embodiment, second level shift receiver1420may have a down level shift circuit1605and an inverter circuit1610. In some embodiments second level shift receiver1420may be constructed in a similar manner as first level shift receiver1410(seeFIG.15), except the second level shift receiver may have only one down level shifting circuit (e.g., enhancement-mode transistor1615) and a follow on inverter circuit1610. In one embodiment, down level shift circuit1605may receive the (L_SHIFT2) signal from second level shift transistor205(seeFIG.2). In one embodiment, inverter circuit1610may be driven by the (Vboot) signal, and the gate voltage of the pull up transistor of the inverter may be used as the (BLANK_FET) signal driving blanking transistor1440(seeFIG.14). In some embodiments the voltage may go from 0 volts in a low state to (Vboot+0.5*(Vboot−Vth)) in a high state. Similar to first level shift receiver1410, second level shift receiver1420may have a diode connected transistor clamp1620across the gate to source of source follower transistor1615. In other embodiments, clamp1620may include fewer or more than three diode connected transistors. Now referring toFIG.17, pull up trigger circuit1425is illustrated in greater detail. In one embodiment, pull up trigger circuit1425may have a first inverter1705, a second inverter1710, an RC pulse generator1715and a gate to source clamp1720. In some embodiments pull up trigger circuit1425may receive the (L_SHIFT1) signal as an input, and in response, generate a pulse as soon as the (L_SHIFT1) voltage transitions to approximately the input threshold of first inverter1705. The generated pulse may be used as the (PULLUP_FET) signal that drives pull up transistor1435(seeFIG.14). Second inverter1710may be driven by (Vboot) instead of (Vdd_HS) because pull up transistor1435gate voltage may need to be larger than the (L_SHIFT1) signal voltage. Now referring toFIG.18, high side UVLO circuit1415is illustrated in greater detail. In one embodiment, high side UVLO circuit1415may have down level shifter1805, a resistor pull up inverter with asymmetric hysteresis1810and a gate to source clamp1815. In further embodiments, the (HS_UVLO) signal generated by high side UVLO circuit1415may aid in preventing circuit failure by turning off the (HS_GATE) signal generated by high side drive circuit130(seeFIG.14) when bootstrap capacitor110voltage goes below a certain threshold. In some embodiments, bootstrap capacitor110voltage (Vboot) (i.e., a floating power supply voltage) is measured, and in response, a logic signal is generated and combined with the output signal (LS_HSG) from first level shift receiver1410which is then used as the input to the high side gate drive circuit130. More specifically, in this embodiment, for example, the UVLO circuit is designed to engage when (Vboot) reduces to less than 4*Vth above switch node (Vsw) 145 voltage. In other embodiments a different threshold level may be used. In further embodiments, high side UVLO circuit1415may down shift (Vboot) in down level shifter1805and transfer the signal to inverter with asymmetric hysteresis1810. The output of inverter with asymmetric hysteresis1810may generate the (HS_UVLO) signal which is logically combined with the output from the first level shift receiver1410to turn off high side transistor125(seeFIG.1). In some embodiments the hysteresis may be used to reduce the number of self-triggered turn on and turn off events of high side transistor125(seeFIG.1), that may be detrimental to the overall performance of half bridge circuit100. Now referring toFIG.19, high side transistor driver130is illustrated in greater detail. High side transistor driver130may have a first inverter stage1905followed by a high side drive stage1910. First inverter stage1905may invert the down shifted (LS_HSG) signal received from level shift1receiver1410(seeFIG.15). The downshifted signal may then be sent through high side drive stage1910. High side drive stage1910may generate the (HS_GATE) signal to drive high side transistor125(seeFIG.1). In further embodiments first inverter stage1905may contain a two input NOR gate that may ensure high side transistor125(seeFIG.1) is turned off when the (HS_UVLO) signal is in a high state. Now referring toFIG.20, a reference voltage generation circuit2000may be used, to generate a high side reference voltage from a supply rail. Such a circuit maybe placed on the high side GaN device105for generating internal power supplies which are referenced to the switch node voltage145. In some embodiments, circuit2000may be similar to startup circuit155inFIG.9. One difference in circuit2000may be the addition of a source follower capacitor2010connected between first node2011and second node2012. In some embodiments, source follower capacitor2010may be needed to ensure that a well regulated voltage, which does not fluctuate with dv/dt appearing at the switch node (Vsw)145, develops between the first node2011and the second node2012. In other embodiments a reference voltage capacitor2015may be connected between a source of reference voltage transistor2055and second node2012. In some embodiments the drain of the reference voltage transistor2055may be connected to the (Vboot) node. In some embodiments, reference voltage capacitor2015may be needed to ensure that (Vref) is well regulated and does not respond to high dv/dt conditions at switch node (Vsw)145(seeFIG.1). In yet further embodiments, another difference in circuit2000may be that second node2012may be coupled to a constantly varying voltage, such as switch node (Vsw)145(seeFIG.1), rather than a ground connection through a current sink circuit915(seeFIG.9). In yet further embodiments (Vref) can be used as (Vdd_HS) in the half bridge circuit100. Another difference in circuit2000may be the addition of a high-voltage diode connected transistor2025(i.e., the gate of the transistor is coupled to the source of the transistor) coupled between depletion-mode transistor2005and series of identical diode connected enhancement-mode low-voltage transistors2020. More specifically, high-voltage diode connected transistor2025may have source coupled to the source of depletion-mode transistor2005, a drain coupled to first node2011and a gate coupled to its source. High-voltage diode connected transistor2025may be used to ensure that source follower capacitor2010does not discharge when the voltage at the top plate of the source follower capacitor rises above (V+). In further embodiments source follower capacitor2010may be relatively small and may be integrated on a semiconductor substrate or within an electronic package. Also shown inFIG.21is bootstrap capacitor110that may be added externally in a half bridge circuit. In some embodiments, shield capacitor160(seeFIG.1) may be connected from first level shift node305(seeFIG.3) and second level shift node (not shown) to switch node145to assist in reducing the false triggering discussed above. In some embodiments, the larger the value of shield capacitor160, the more immune the circuit will be to false triggering effects due to the parasitic capacitance to ground. However, during high side transistor125turn off, shield capacitor160may be discharged through pull up resistor303(seeFIG.3) connected to first level shift node305. This may significantly slow down high side transistor125turn off process. In some embodiments this consideration may be used to set an upper limit on the value of shield capacitor160. In further embodiments, an overvoltage condition on first level shift node305(seeFIG.3) may be prevented by the use of a clamp circuit161(seeFIG.1) between the first level shift node and switch node145. In some embodiments, clamp circuit161maybe composed of a diode connected transistor where a drain of the transistor is connected to first level shift node305(seeFIG.3) and a gate and a source are connected to switch node (Vsw)145(seeFIG.1). In further embodiments, a second shield capacitor and a second clamp circuit may be placed between the second level shift node and switch node (Vsw)145(seeFIG.1). Half Bridge Circuit #1Operation The following operation sequence for half-bridge circuit100is for example only and other sequences may be used without departing from the invention. Reference will now be made simultaneously toFIGS.1,2and14. In one embodiment, when the (PWM_LS) signal from the controller is high, low side logic, control and level shift circuit150sends a high signal to low side transistor driver120. Low side transistor driver120then communicates through the (LS_GATE) signal to low side transistor115to turn it on. This will set the switch node voltage (Vsw)145close to 0 volts. When low side transistor115turns on, it provides a path for bootstrap capacitor110to become charged through bootstrap charging circuit157which may be connected between (Vcc) and (Vboot). The charging path has a parallel combination of a high voltage bootstrap diode1205(seeFIG.12) and transistor1210. The (BOOTFET_DR) signal provides a drive signal to bootstrap transistor1210(seeFIG.12) that provides a low resistance path for charging bootstrap capacitor110. Bootstrap diode1205(seeFIG.12) may be used to ensure that there is a path for charging bootstrap capacitor110during startup when there is no low side transistor115gate drive signal (LS_GATE). During this time the (PWM_HS) signal should be low. If the (PWM_HS) signal is inadvertently turned on (i.e., in a high state) during this time the (STP_HS) signal generated from low side transistor driver120will prevent high side transistor125from turning on. If the (PWM_LS) signal is turned on while the (PWM_HS) signal is on, the (STP_LS) signal generated from level shift driver circuit217will prevent low side transistor115from turning on. Also, in some embodiments the (LS_UVLO) signal may prevent low side transistor115and high side transistor125from turning on when either (Vcc) or (Vdd_LS) goes below a preset threshold voltage level. In further embodiments, when the (PWM_LS) signal is low, low side gate signal (LS_GATE) to low side transistor115is also low. During the dead time between the (PWM_LS) signal low state to the (PWM_HS) high state transition, an inductive load will force either high side transistor125or low side transistor115to turn on in the synchronous rectifier mode, depending on direction of power flow. If high side transistor125turns on during the dead time (e.g., during boost mode operation), switch node (Vsw) 145 voltage may rise close to (V+)135(rail voltage). In some embodiments, a dv/dt condition on switch node145(Vsw) may tend to pull first level shift node (LSHIFT_1)305(seeFIG.3) to a low state relative to switch node (Vsw)145, due to capacitive coupling to ground. This may turn on high side gate drive circuit130causing unintended triggering of high side transistor125. In one embodiment, this may result in no dead time which may harm half bridge circuit100with a shoot through condition. In further embodiments, to prevent this condition from occurring, blanking pulse generator223may sense the turn off transient of low side transistor115and send a pulse to turn on second level shift transistor205. This may pull the (L_SHIFT2) signal voltage to a low state which then communicates with second level shift receiver1420to generate a blanking pulse signal (B_PULSE) to drive blanking transistor1440. Blanking transistor1440may then act as a pull up to prevent first level shift node (LSHIFT_1)305(seeFIG.3) from going to a low state relative to switch node (Vsw)145. In further embodiments, after the dead time, when the (PWM_HS) signal goes to a high state, level shift driver circuit217may send a high signal to the gate of first level shift transistor203(via the L1_DR signal from level shift driver circuit217). The high signal will pull first level shift node (LSHIFT_1)305(seeFIG.3) low relative to switch node (Vsw)145which will result in a high signal at the input of high side transistor125, turning on high side transistor125. Switch node voltage (Vsw)145will remain close to (V+)135. In one embodiment, during this time, bootstrap capacitor110may discharge through first level shift transistor203(which is in an on state during this time). If high side transistor125stays on for a relatively long time (i.e., a large duty cycle) bootstrap capacitor110voltage will go down to a low enough voltage that it will prevent high side transistor125from turning off when the (PWM_HS) signal goes low. In some embodiments this may occur because the maximum voltage the (L_SHIFT1) signal can reach is (Vboot) which may be too low to turn off high side transistor125. In some embodiments, this situation may be prevented by high side UVLO circuit1415that forcibly turns off high side transistor125by sending a high input to high side gate drive circuit130when (Vboot) goes below a certain level. In yet further embodiments, when the (PWM_HS) signal goes low, first level shift transistor203will also turn off (via the L1_DR signal from the level shift driver circuit217). This will pull first level shift node (LSHIFT_1)305(seeFIG.3) to a high state. However, in some embodiments this process may be relatively slow because the high value pull up resistor303(seeFIG.3) (used to reduce power consumption in some embodiments) needs to charge all the capacitances attached to first level shift node (L_SHIFT1)305(seeFIG.3) including the output capacitance (Coss) of first level shift transistor213and shield capacitor160. This may increase the turn off delay of high side transistor125. In order to reduce high side transistor125turn off delay, pull up trigger circuit1425may be used to sense when first level shift node (L_SHIFT1)305(seeFIG.3) goes above (Vth). This condition may generate a (PULLUP_FET) signal that is applied to pull up transistor1435which, acting in parallel with pull up resistor1430, may considerably speed up the pull up of first level shift node (L_SHIFT1)305(seeFIG.3) voltage, hastening the turn off process. Half Bridge Circuit #2 Now referring toFIG.21, a second embodiment of a half bridge circuit2100is disclosed. Half bridge circuit2100may have the same block diagram as circuit100illustrated inFIG.1, however the level shift transistors in circuit2100may operate with pulsed inputs, rather than a continuous signal, as described in more detail below. In some embodiments, pulsed inputs may result in lower power dissipation, reduced stress on the level shift transistors and reduced switching time, as discussed in more detail below. Continuing to refer toFIG.21, one embodiment includes an integrated half bridge power conversion circuit2100employing a low side GaN device2103, a high side GaN device2105, a load2107, a bootstrap capacitor2110and other circuit elements, as discussed in more detail below. Some embodiments may also have an external controller (not shown inFIG.21) providing one or more inputs to circuit2100to regulate the operation of the circuit. Circuit2100is for illustrative purposes only and other variants and configurations are within the scope of this disclosure. As further illustrated inFIG.21, in one embodiment, integrated half bridge power conversion circuit2100may include a low side circuit disposed on low side GaN device2103that includes a low side transistor2115having a low side control gate2117. The low side circuit may further include an integrated low side transistor driver2120having an output2123connected to a low side transistor control gate2117. In another embodiment there may be a high side circuit disposed on high side GaN device2105that includes a high side transistor2125having a high side control gate2127. The high side circuit may further include an integrated high side transistor driver2130having an output2133connected to high side transistor control gate2127. High side transistor2125may be used to control the power input into power conversion circuit2100and have a voltage source (V+)2135(sometimes called a rail voltage) connected to a drain2137of the high side transistor. High side transistor2125may further have a source2140that is coupled to a drain2143of low side transistor2115, forming a switch node (Vsw)2145. Low side transistor2115may have a source2147connected to ground. In one embodiment, low side transistor2115and high side transistor2125may be enhancement-mode field-effect transistors. In other embodiments low side transistor2115and high side transistor2125may be any other type of device including, but not limited to, GaN-based depletion-mode transistors, GaN-based depletion-mode transistors connected in series with silicon based enhancement-mode field-effect transistors having the gate of the depletion-mode transistor connected to the source of the silicon-based enhancement-mode transistor, silicon carbide based transistors or silicon-based transistors. In some embodiments high side device2105and low side device2103may be made from a GaN-based material. In one embodiment the GaN-based material may include a layer of GaN on a layer of silicon. In further embodiments the GaN based material may include, but not limited to, a layer of GaN on a layer of silicon carbide, sapphire or aluminum nitride. In one embodiment the GaN based layer may include, but not limited to, a composite stack of other III nitrides such as aluminum nitride and indium nitride and III nitride alloys such as AlGaN and InGaN Low Side Device Low side device2103may have numerous circuits used for the control and operation of the low side device and high side device2105. In some embodiments, low side device2103may include a low side logic, control and level shift circuit (low side control circuit)2150that controls the switching of low side transistor2115and high side transistor2125along with other functions, as discussed in more detail below. Low side device2103may also include a startup circuit2155, a bootstrap capacitor charging circuit2157and a shield capacitor2160, as also discussed in more detail below. Now referring toFIG.22, the circuits within low side control circuit2150are functionally illustrated. Each circuit within low side control circuit2150is discussed below, and in some cases is shown in more detail inFIGS.23-28. In one embodiment the primary function of low side control circuit2150may be to receive one or more input signals, such as a PWM signal from a controller, and control the operation of low side transistor2115, and high side transistor2125. First level shift transistor2203, may be an “on” pulse level shift transistor, while second level shift transistor2215may be an “off” pulse level shift transistor. In one embodiment, a pulse width modulated high side (PWM_HS) signal from a controller (not shown) may be processed by inverter/buffer2250and sent on to an on pulse generator2260and an off pulse generator2270. On pulse generator2260may generate a pulse that corresponds to a low state to high state transient of the (PWM_HS) signal, thus turning on first level shift transistor2203during the duration of the pulse. Off pulse generator2270may similarly generate a pulse that corresponds to the high state to low state transition of the (PWM_HS) signal, thus turning on second level shift transistor2205for the duration of the off pulse. First and second level shift transistors2203,2205, respectively, may operate as pull down transistors in resistor pull up inverter circuits. More specifically, turning on may mean the respective level shift node voltages get pulled low relative to switch node (Vsw)2145voltage, and turning off may result in the respective level shift nodes assuming the (Vboot) voltage. Since first and second level shift transistors2203,2215, respectively, are “on” only for the duration of the pulse, the power dissipation and stress level on these two devices may be less than half bridge circuit100illustrated inFIG.1. First and second resistors2207,2208, respectively, may be added in series with the sources of first and second level shift transistors2203,2215, respectively to limit the gate to source voltage and consequently the maximum current through the transistors. First and second resistors2207,2208, respectively, could be smaller than the source follower resistors in half bridge circuit100illustrated inFIG.1, which may help make the pull down action of first and second level shift transistors2203,2215faster, reducing the propagation delays to high side transistor2125. In further embodiments, first and second resistors2207,2208, respectively, could be replaced by any form of a current sink. One embodiment may connect the source of first and second level shift transistors2203,2205, respectively to a gate to source shorted depletion-mode device. One embodiment of a depletion-mode transistor formed in a high-voltage GaN technology may be to replace the enhancement-mode gate stack with one of the high-voltage field plate metals superimposed on top of the field dielectric layers. The thickness of the field dielectric and the work function of the metal may control the pinch-off voltage of the stack. In further embodiments, first and second resistors2207,2208, respectively may be replaced by a current sink. In one embodiment a reference current (Iref) that is generated by startup circuit2155(seeFIG.21) may be used. Both the depletion-mode transistor and current sink embodiments may result in a significant die area reduction compared to the resistor option (i.e., because a small depletion transistor would suffice and Iref is already available). Bootstrap transistor drive circuit2225may be similar to bootstrap transistor drive circuit225illustrated inFIG.2above. Bootstrap transistor drive circuit2225may receive input from low side drive circuit2220(seeFIG.22) and provide a gate drive signal called (BOOTFET_DR) to the bootstrap transistor in bootstrap capacitor charging circuit2157(seeFIG.21), as discussed in more detail above. Now referring toFIG.23, first level shift transistor2203is illustrated along with a pull up resistor2303that may be located in high side device2105. In some embodiments, first level shift transistor2203may operate as a pull down transistor in a resistor pull up inverter similar to first level shift transistor203illustrated inFIG.3. As discussed above, pull up resistor2303may be disposed in high side device2105(seeFIG.21). Second level shift transistor2215may have a similar configuration. In some embodiments there may be a first capacitance between the first output terminal (LS NODE)2305and switch node (Vsw)2145(seeFIG.21), and a second capacitance between a first output terminal2305and ground, where the first capacitance is greater than the second capacitance. The first capacitance may be designed such that in response to a high dv/dt signal at the switch node (Vsw)2145(seeFIG.21), a large portion of the C*dv/dt current is allowed to conduct through the first capacitance ensuring that the voltage at first output terminal2305tracks the voltage at the switch node (Vsw). A shield capacitor2160(seeFIG.21) may be configured to act as the first capacitor as described above. In further embodiments shield capacitor2160(seeFIG.21) may be used to create capacitance between first output terminal2305and switch node (Vsw)2145(seeFIG.21) in the half bridge power conversion circuit2100. Shield capacitor2160may also be used to minimize the capacitance between first output terminal2305and a substrate of the semiconductor device. In further embodiments shield capacitor2160may be constructed on low side GaN device2103. Now referring toFIG.24, inverter/buffer circuit2250is illustrated in greater detail. In one embodiment inverter/buffer circuit2250may have a first inverter stage2405and a first buffer stage2410. In further embodiments, inverter/buffer circuit2250may be driven directly by the (PWM_HS) signal from the controller (not shown). The output of first inverter stage2405may be the input signal (PULSE_ON) to on pulse generator2260(seeFIG.22) while the output of first buffer stage2410may be an input signal (PULSE_OFF) to off pulse generator2270. In some embodiments, an optional (LS_UVLO) signal may be generated by sending a signal generated by UVLO circuit2227(seeFIG.22) in to a NAND gate disposed in first inverter stage2405. This circuit may be used to turn off the level shift operation if either (Vcc) or (Vdd_LS) go below a certain reference voltage (or a fraction of the reference voltage). In further embodiments, inverter/buffer circuit2250may also generate a shoot through protection signal (STP_LS1) for low side transistor2115(seeFIG.21) that may be applied to low side transistor gate drive circuit2120. This may turn off low side transistor gate drive circuit2120(seeFIG.21) when the (PWM_HS) signal is high, preventing shoot through. Now referring toFIG.25, on pulse generator2260is illustrated in greater detail. In one embodiment on pulse generator2260may have a first inverter stage2505, a first buffer stage2510, an RC pulse generator2515, a second inverter stage2520a third inverter stage2525and a third buffer stage2530. In further embodiments the (PULSE_ON) signal input from inverter/buffer circuit2250(seeFIG.22) may be first inverted and then transformed into an on pulse by RC pulse generator2515and a square wave generator. The result of this operation is the gate drive signal (LI_DR) that is transmitted to first level shift transistor2203(seeFIG.22). In further embodiments, on pulse generator2260may comprise one or more logic functions, such as for example, a binary or combinatorial function. In one embodiment, on pulse generator2260may have a multiple input NOR gate for the (STP_HS) signal. The (STP_HS) signal may have the same polarity as the (LS_GATE) signal. Therefore, if the (STP_HS) signal is high (corresponding to LS_GATE signal being high) the on pulse may not be generated because first inverter circuit2505inFIG.25will be pulled low which will deactivate pulse generator2515. In further embodiments, RC pulse generator2515may include a clamp diode (not shown). The clamp diode may be added to ensure that RC pulse generator2515works for very small duty cycles for the (PWM_LS) signal. In some embodiments, on pulse generator2260may be configured to receive input pulses in a range of 2 nanoseconds to 20 microseconds and to transmit pulses of substantially constant duration within the range. In one embodiment the clamp diode may turn on and short out a resistor in RC pulse generator2515(providing a very small capacitor discharge time) if the voltage across the clamp diode becomes larger than (Vth). This may significantly improve the maximum duty cycle of operation (with respect to the PWM_HS signal) of pulse generator circuit2260. Now referring toFIG.26, off pulse generator2270is illustrated in greater detail. In one embodiment off pulse generator2270may have an RC pulse generator2603, a first inverter stage2605, a second inverter stage2610and a first buffer stage2615. In further embodiments, off pulse generator2270may receive an input signal (PULSE_OFF) from inverter/buffer circuit2250(seeFIG.22) that may be subsequently communicated to RC pulse generator2603. In further embodiments the pulse from RC pulse generator2603is sent through first inverter stage2605, second inverter stage2610and buffer stage2615. The pulse may then be sent as the (L2_DR) signal to second level shift transistor2215(seeFIG.22). A clamp diode may also be included in off pulse generator2270. In some embodiments, the operating principle may be similar to the operating principle discussed above with regard to on pulse generator2260(seeFIG.25). Such operating principles may ensure that off pulse generator2270operates for very low on times of high side transistor2125(seeFIG.21) (i.e. the circuit will operate for relatively small duty cycles). In some embodiments, off pulse generator2270may be configured to receive input pulses in a range of 2 nanoseconds to 20 microseconds and to transmit pulses of substantially constant duration within the range. In further embodiments an off level shift pulse can be shortened by an on input pulse to enable an off time of less than 50 nanoseconds on high side transistor2125. In some embodiments, RC pulse generator2603may include a capacitor connected with a resistor divider network. The output from the resistor may be a signal (INV) that is sent to an inverter2275(seeFIG.22) that generates a shoot through protection signal (STP_LS2) transmitted to low side driver circuit2220. In further embodiments, off pulse generator2270may comprise one or more logic functions, such as for example, a binary or combinatorial function. In one embodiment the (STP_LS2) signal is sent to a NAND logic circuit within low side driver circuit2220, similar to the (STP_LS1) signal. In some embodiments, these signals may be used to ensure that during the duration of the off pulse signal (PULSE_OFF), low side transistor2115(seeFIG.21) does not turn on (i.e., because high side transistor2125turns off during the off pulse). In some embodiments this methodology may be useful to compensate for a turn off propagation delay (i.e., the PULSE_OFF signal may enable shoot through protection), ensuring that low side transistor2115will only turn on after high side transistor2125gate completely turns off. In further embodiments, a blanking pulse can be level shifted to high side device2105using second level shift transistor2215. To accomplish this, a blanking pulse may be sent into a NOR input into first inverter stage2605. The blanking pulse may be used to inhibit false triggering due to high dv/dt conditions at switch node Vsw2145(seeFIG.20). In some embodiments no blanking pulse may be used to filter dv/dt induced or other unwanted level shift output pulses. Now referring toFIG.27, blanking pulse generator2223is illustrated in greater detail. In one embodiment, blanking pulse generator2223may be a more simple design than used in half bridge circuit100illustrated inFIG.1because the square wave pulse generator is already part of off pulse generator2270. In one embodiment the (LS_GATE) signal is fed as the input to blanking pulse generator2223from low side gate drive circuit2220(seeFIG.22). This signal may be inverted and then sent through an RC pulse generator to generate a positive going pulse. In some embodiments, an inverted signal may be used because the pulse needs to correspond to the falling edge of the (LS_GATE) signal. The output of this may be used as the blanking pulse input (B_PULSE) to off pulse generator2270. Now referring toFIG.28, low side transistor drive circuit2220is illustrated in greater detail. In one embodiment low side transistor drive circuit2220may have a first inverter stage2805, a first buffer stage2810, a second inverter stage2815, a second buffer stage2820and a third buffer stage2825. In some embodiments two inverter/buffer stages may be used because the input to the gate of low side transistor2115is synchronous with the (PWM_LS) signal. Thus, in some embodiments a (PWM_LS) high state may correspond to a (LS_GATE) high state and vice versa. In further embodiments, low side transistor drive circuit2220may also include an asymmetric hysteresis using a resistor divider with a transistor pull down similar to the scheme described in120(seeFIG.8). In one embodiment low side transistor drive circuit2220includes multiple input NAND gates for the (STP_LS1) and (STP_LS2) (shoot through prevention on low side transistor2115) signals. The (STP_LS1) and (STP_LS2) signals may ensure that low side transistor drive circuit2220(seeFIG.22) does not communicate with low side transistor2115(seeFIG.21) when high side transistor2125is on. This technique may be used to avoid the possibility of shoot-through. Other embodiments may include NAND gates (similar to the ones employed above inFIG.28) for the (LS_UVLO) signal. One embodiment may include a turn off delay resistor in series with the gate of the final pull down transistor. This may be used to ensure the bootstrap transistor is turned off before low side transistor2115turns off. In further embodiments, low side device2103(seeFIG.21) may also include a startup circuit2155, bootstrap capacitor charging circuit2157, a shield capacitor2160, and a UVLO circuit2227that may be similar to startup circuit155, bootstrap capacitor charging circuit157, shield capacitor160and UVLO circuit227, respectively, as discussed above. High Side Device Now referring toFIG.29, high side logic and control circuit2153and how it interacts with high side transistor driver2130is illustrated in greater detail. In some embodiments, high side logic and control circuit2153may operate in similar ways as high side logic and control circuit153, discussed above inFIG.15. In further embodiments, high side logic and control circuit2153may operate in different ways, as discussed in more detail below. In one embodiment, level shift1receiver circuit2910receives an (L_SHIFT1) signal from first level shift transistor2203(seeFIG.22) that receives an on pulse at the low state to high state transition of the (PWM_HS) signal, as discussed above. In response, level shift1receiver circuit2910drives a gate of pull up transistor2960(e.g., in some embodiments a low-voltage enhancement-mode GaN transistor). In further embodiments, pull up transistor2960may then pull up a state storing capacitor2955voltage to a value close to (Vdd_HS) with respect to switch node (Vsw)2145voltage. The voltage on a state storing capacitor2955may then be transferred to high side transistor driver2130and on to the gate of high side transistor gate2127(seeFIG.21) to turn on high side transistor2125. In some embodiments state storing capacitor2955may be a latching storage logic circuit configured to change state in response to a first pulsed input signal and to change state in response to a second pulsed input signal. In further embodiments, state storing capacitor2955may be replaced by any type of a latching circuit such as, but not limited to an RS flip-flop. In further embodiments, during this time, level shift2receiver circuit2920may maintain pull down transistor2965(e.g., in some embodiments a low-voltage enhancement-mode GaN transistor) in an off state. This may cut off any discharge path for state storing capacitor2955. Thus, in some embodiments, state storing capacitor2955may have a relatively small charging time constant and a relatively large discharge time constant. Similarly, level shift2receiver2920may receive an (L_SHIFT2) signal from second level shift transistor2215(seeFIG.22) that receives an off pulse at the high state to low state transition of the (PWM_HS) signal, as discussed above. In response, level shift2receiver circuit2920drives a gate of pull down transistor2965(e.g., in some embodiments a low-voltage enhancement-mode GaN transistor). In further embodiments, pull down transistor2965may then pull down (i.e., discharge) state storing capacitor2955voltage to a value close to switch node (Vsw)2145, that may consequently turn off high side transistor2125through high side transistor driver2130. Continuing to refer toFIG.29, first and second shield capacitors2970,2975, respectively, may be connected from (L_SHIFT1) and (L_SHIFT2) nodes to help prevent false triggering during high dv/dt conditions at switch node (Vsw)2145(seeFIG.21). In further embodiments there may also be a clamp diode between the (L_SHIFT1) and (L_SHIFT2) nodes and the switch node (Vsw)2145(seeFIG.21). This may ensure that the potential difference between switch node (Vsw)2145(seeFIG.21) and the (L_SHIFT1) and (L_SHIFT2) nodes never goes above (Vth). This may be used to create a relatively fast turn on and turn off for high side transistor2125(seeFIG.21). Now referring toFIG.30, level shift1receiver2910is illustrated in greater detail. In one embodiment level shift1receiver2910may include a down level shifter3005, a first inverter3010, a second inverter3015, a first buffer3020, a third inverter3025, a second buffer3030and a third buffer3135. In some embodiments, level shift1receiver2910down shifts (i.e., modulates) the (L_SHIFT1) signal by a voltage of 3*Vth (e.g., using three enhancement-mode transistors where each may have a gate to source voltage close to Vth). In other embodiments a fewer or more downshift transistors may be used. In further embodiments, the last source follower transistor may have a three diode connected transistor clamp across its gate to its source. In some embodiments this configuration may be used because its source voltage can only be as high as (Vdd_HS) (i.e., because its drain is connected to Vdd_HS) while its gate voltage can be as high as V (L_SHIFT1)−2*Vth. Thus, in some embodiments the maximum gate to source voltage on the final source follower transistor can be greater than the maximum rated gate to source voltage in the technology. In further embodiments, first inverter3010may also have a NOR Gate for the high side under voltage lock out using the (UV_LS1) signal generated by high side UVLO circuit2915. In one embodiment, an output of level shift1receiver2910(seeFIG.29) may be a (PU_FET) signal that is communicated to a gate of pull up transistor2960(seeFIG.29). This signal may have a voltage that goes from 0 volts in a low state to (Vdd_HS)+(Vdd_HS−Vth) in a high state. This voltage may remain on for the duration of the on pulse. Now referring toFIG.31, level shift2receiver2920is illustrated in greater detail. In one embodiment level shift2receiver2920may be similar to level shift1receiver2910discussed above. In further embodiments level shift2receiver2920may include a blanking pulse generator3105, a down level shifter3110, a first inverter3115, a second inverter3120, a first buffer3125, an third inverter3130, a second buffer3135and a third buffer3140. In one embodiment, blanking pulse generator3105may be used in addition to a 3*Vth down level shifter3110and multiple inverter/buffer stages. In other embodiments different configurations may be used. In some embodiments, this particular configuration may be useful when level shift2receiver2920doubles as a high side transistor2125(seeFIG.21) turn off as well as a blanking transistor2940(seeFIG.29) drive for better dv/dt immunity. In some embodiments, blanking pulse generator3105may be identical to level shift2receiver1520illustrated inFIG.17. In one embodiment level shift2receiver2920(seeFIG.29) may receive (L_SHIFT2) and (UV_LS2) signals and in response, transmit a (PD_FET) signal to pull down transistor2965. In further embodiments, first inverter3115may have a two input NAND gate for the (UV_LS2) signal from high side UVLO circuit2915(seeFIG.29). Now referring toFIG.32, high side UVLO circuit2915is illustrated in greater detail. In one embodiment high side UVLO circuit2915may include a down level shifter3205and a resistor pull up inverter stage3210. In some embodiments, high side UVLO circuit2915may be configured to prevent circuit failure by turning off the (HS_GATE) signal to high side transistor2125(seeFIG.21) when bootstrap capacitor2110voltage goes below a certain threshold. In one example embodiment high side UVLO circuit2915is designed to engage when (Vboot) reduces to a value less than 4*Vth below switch node (Vsw)2145voltage. In another embodiment the output of down level shifter3205may be a (UV_LS2) signal transmitted to second level shift receiver2920and the output of resistor pull up inverter stage3210may be an (UV_LS1) signal that is transmitted to first level shift receiver2910. As discussed below, in some embodiments high side UVLO circuit2915may be different from high side UVLO circuit1415for half bridge circuit100discussed above inFIGS.14and18, respectively. In one embodiment, the (Vboot) signal may be down shifted by 3*Vth and transferred to resistor pull up inverter stage3210. In further embodiments, since level shift2receiver circuit2920(seeFIG.29) controls the turn off process based on high side transistor2125(seeFIG.21), directly applying a 3*Vth down shifted output to the NAND gate at the input of level shift2receiver circuit2920will engage the under voltage lock out. However, in some embodiments, because the bootstrap voltage may be too low this may also keep pull up transistor2960(seeFIG.29) on. In some embodiments, this may result in a conflict. While level shift2receiver circuit2920(seeFIG.29) tries to keep high side transistor2125(seeFIG.21) off, level shift1receiver circuit2910may try to turn the high side transistor on. In order to avoid this situation, some embodiments may invert the output of the 3*Vth down shifted signal from high side UVLO circuit2915(seeFIG.29) and send it to a NOR input on level shift1receiver circuit2910. This may ensure that level shift1receiver circuit2910does not interfere with the UVLO induced turn off process. Now referring toFIG.33, high side transistor driver2130is illustrated in greater detail. In one embodiment high side transistor driver2130may include a first inverter3305, a first buffer3310, a second inverter3315, a second buffer3320and a third buffer3325. In some embodiments high side transistor driver2130may be a more basic design than high side transistor driver130employed in half bridge circuit100illustrated inFIG.1. In one embodiment, high side transistor driver2130receives an (S CAP) signal from state storage capacitor2955(seeFIG.29) and delivers a corresponding drive (HS_GATE) signal to high side transistor2125(seeFIG.21). More specifically, when the (S CAP) signal is in a high state, the (HS_GATE) signal is in a high state and vice versa. Half Bridge Circuit #2Operation The following operation sequence for half-bridge circuit2100(seeFIG.21) is for example only and other sequences may be used without departing from the invention. Reference will now be made simultaneously toFIGS.21,22and29. In one embodiment, when the (PWM_LS) signal is in a high state, low side logic, control and level shift circuit2150may send a high signal to low side transistor driver2120which then communicates that signal to low side transistor2115to turn it on. This may set switch node (Vsw)2145voltage close to 0 volts. In further embodiments, when low side transistor2115turns on it may provide a path for bootstrap capacitor2110to charge. The charging path may have a parallel combination of a high-voltage bootstrap diode and transistor. In some embodiments, bootstrap transistor drive circuit2225may provide a drive signal (BOOTFET_DR) to the bootstrap transistor that provides a low resistance path for charging bootstrap capacitor2110. In one embodiment, the bootstrap diode may ensure that there is a path for charging bootstrap capacitor2110during startup when there is no low side gate drive signal (LS_GATE). During this time the (PWM_HS) signal should be in a low state. If the (PWM_HS) signal is inadvertently turned on during this time, the (STP_HS) signal generated from low side driver circuit2220may prevent high side transistor2125from turning on. If the (PWM_LS) signal is turned on while the (PWM_HS) signal is on, then the (STP_LS1) and (STP_LS2) signals generated from inverter/buffer2250and inverter2275, respectively will prevent low side transistor2115from turning on. In addition, in some embodiments the (LS_UVLO) signal may prevent low side gate2117and high side gate2127from turning on when either (Vcc) or (Vdd_LS) go below a predetermined voltage level. Conversely, in some embodiments when the (PWM_LS) signal is in a low state, the (LS_GATE) signal to low side transistor2115may also be in a low state. In some embodiments, during the dead time between the (PWM_LS) low signal and the (PWM_HS) high signal transition, the inductive load may force either high side transistor2125or low side transistor2115to turn on in the synchronous rectifier mode, depending on the direction of power flow. If high side transistor2125turns on during the dead time (e.g., in a boost mode), switch node (Vsw)2145voltage may rise close to (V+)2135(i.e., the rail voltage). This dv/dt condition on switch node (Vsw)2145may tend to pull the (L_SHIFT1) node to a low state relative to the switch node (i.e., because of capacitive coupling to ground) which may turn on high side transistor driver2130causing unintended conduction of high side transistor2125. This condition may negate the dead time, causing shoot through. In some embodiments this condition may be prevented by using blanking pulse generator2223to sense the turn off transient of low side transistor2115and send a pulse to turn on second level shift transistor2205. This may pull the (L_SHIFT2) signal to a low state which may then communicate with level shift2receiver circuit2920to generate a blanking pulse to drive blanking transistor2940. In one embodiment, blanking transistor2940may act as a pull up to prevent the (L_SHIFT1) signal from going to a low state relative to switch node (Vsw)2145. In further embodiments, after the dead time when the (PWM_HS) signal transitions from a low state to a high state, an on pulse may be generated by on pulse generator2260. This may pull the (L_SHIFT1) node voltage low for a brief period of time. In further embodiments this signal may be inverted by level shift1receiver circuit2910and a brief high signal will be sent to pull up transistor2960that will charge state storage capacitor2955to a high state. This may result in a corresponding high signal at the input of high side transistor driver2130which will turn on high side transistor2125. Switch node (Vsw)2145voltage may remain close to (V+)2135(i.e., the rail voltage). State storing capacitor2955voltage may remain at a high state during this time because there is no discharge path. In yet further embodiments, during the on pulse, bootstrap capacitor2110may discharge through first level shift transistor2203. However, since the time period is relatively short, bootstrap capacitor2110may not discharge as much as it would if first level shift transistor2203was on during the entire duration of the (PWM_HS) signal (as was the case in half bridge circuit100inFIG.1). More specifically, in some embodiments this may result in the switching frequency at which the UVLO engages to be a relatively lower value than in half bridge circuit100inFIG.1. In some embodiments, when the (PWM_HS) signal transitions from a high state to a low state, an off pulse may be generated by off pulse generator2270. This may pull the (L_SHIFT2) node voltage low for a brief period of time. This signal may be inverted by level shift2receiver circuit2920and a brief high state signal may be sent to pull down transistor2965that will discharge state storing capacitor2955to a low state. This will result in a low signal at the input of high side transistor driver2130that will turn off high side transistor2125. In further embodiments, state storing capacitor2955voltage may remain at a low state during this time because it has no discharge path. In one embodiment, since the turn off process in circuit2100does not involve charging level shift node capacitors through a high value pull up resistor, the turn off times may be relatively shorter than in half bridge circuit100inFIG.1. In further embodiments, high side transistor2125turn on and turn off processes may be controlled by the turn on of substantially similar level shift transistors2203,2205, therefore the turn on and turn off propagation delays may be substantially similar. This may result in embodiments that have no need for a pull up trigger circuit and/or a pull up transistor as were both used in half bridge circuit100inFIG.1. ESD Circuits Now referring toFIG.34, in some embodiments, one or more pins (i.e., connections from a semiconductor device within an electronic package to an external terminal on the electronic package) may employ an electro-static discharge (ESD) clamp circuit to protect the circuit. The following embodiments illustrate ESD clamp circuits that may be used on one or more pins in one or more embodiments disclosed herein, as well as other embodiments that may require ESD protection. In further embodiments, the ESD clamp circuits disclosed herein may be employed on GaN-based devices. One embodiment of an electro-static discharge (ESD) clamp circuit3400is illustrated. ESD clamp circuit3400may have a configuration employing one or more source follower stages3405made from enhancement-mode transistors. Each source follower stage3405may have a gate3406connected to a source3407of an adjacent source follower stage. In the embodiment illustrated inFIG.34, four source follower stages3405are employed, however in other embodiments fewer or more may be used. Resistors3410are coupled to sources3407of source follower stages3405. An ESD transistor3415is coupled to one or more source follower stages3405and may be configured to conduct a current greater than 500 mA when exposed to an overvoltage pulse, as discussed below. Resistors3410are disposed between source3420of ESD transistor3415and each source3407of source follower stages3405. Drains3408of source follower stages3405are connected to drain3425of ESD transistor3415. Source3407of the last source follower stage is coupled to gate3430of ESD transistor3415. In one embodiment, a turn on voltage of ESD clamp circuit3400can be set by the total number of source follower stages3405. However, since the last source follower stage is a transistor with a certain drain3408to source3407voltage and gate3406to source voltage the current through the final resistor3410may be relatively large and may result in a larger gate3430to source3420voltage across ESD transistor3415. This condition may result in a relatively large ESD current capability and in some embodiments an improved leakage performance compared to other ESD circuit configurations. In further embodiments, ESD clamp circuit3400may have a plurality of degrees of freedom with regard to transistor sizes and resistor values. In some embodiments ESD clamp circuit3400may be able to be made smaller than other ESD circuit configurations. In other embodiments, the performance of ESD clamp circuit3400may be improved by incrementally increasing the size of source follower stages3405as they get closer to ESD transistor3415. In further embodiments, resistors3410can be replaced by depletion-mode transistors, reference current sinks or reference current sources, for example. Now referring toFIG.35an embodiment similar to ESD clamp circuit3400inFIG.34is illustrated, however ESD clamp circuit3500may have resistors in a different configuration, as discussed in more detail below. ESD clamp circuit3500may have a configuration employing one or more source follower stages3505made from one or more enhancement-mode transistors. Each source follower stage3505may have a gate3506connected to a source3507of an adjacent source follower stage. In the embodiment illustrated inFIG.35, four source follower stages3505are employed, however in other embodiments fewer or more may be used. Resistors3510are coupled between sources3507of adjacent source follower stages3505. An ESD transistor3515is coupled to source follower stages3505with resistor3510disposed between source3520of ESD transistor3515and source3507of a source follower stage3505. Drains3508of source follower stages3505may be coupled together and to drain3525of ESD transistor3515. Electronic Packaging Now referring toFIGS.36and37, in some embodiments, one or more semiconductor devices may be disposed in one or more electronic packages. Myriad packaging configurations and types of electronic packages are available and are within the scope of this disclosure.FIG.36illustrates one example of what is known as a quad-flat no-lead electronic package with two semiconductor devices within it. Electronic package3600may have a package base3610that has one or more die pads3615surrounded by one or more terminals3620. In some embodiments package base3610may comprise a leadframe while in other embodiments it may comprise an organic printed circuit board, a ceramic circuit or another material. In the embodiment depicted inFIG.36, a first device3620is mounted to a first die pad3615and a second device3625is mounted to a second die pad3627. In another embodiment one or more of first and second devices3620,3625, respectively may be mounted on an insulator (not shown) that is mounted to package base3610. In one embodiment the insulator may be a ceramic or other non-electrically conductive material. First and second devices3620,3625, respectively are electrically coupled to terminals3640with wire bonds3630or any other type of electrical interconnect such as, for example, flip-chip bumps or columns that may be used in a flip-chip application. Wirebonds3630may extend between device bond pads3635to terminals3640, and in some cases to die pads3615,3627and in other cases to device bond pads3635on an adjacent device. Now referring toFIG.37, an isometric view of electronic package3600is shown. Terminals3640and die attach pads3615and3627may be disposed on an external surface and configured to attach to a printed circuit board or other device. In further embodiments, terminals3640and die attach pads3615and3627may only be accessible within the inside of electronic package3600and other connections may be disposed on the outside of the electronic package. More specifically, some embodiments may have internal electrical routing and there may not be a one to one correlation between internal and external connections. In further embodiments first and second devices3620,3625, respectively (seeFIG.36) and a top surface of package base3610may be encapsulated by a non-electrically conductive material, such as for example, a molding compound. Myriad other electronic packages may be used such as, but not limited to, SOIC's, DIPS, MCM's and others. Further, in some embodiments each device may be in a separate electronic package while other embodiments may have two or more electronic devices within a single package. Other embodiments may have one or more passive devices within one or more electronic packages. In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indicator of the scope of the invention, and what is intended by the applicants to be the scope of the invention, is the literal and equivalent scope of the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. | 89,646 |
11862997 | DESCRIPTION OF EMBODIMENTS Hereinafter, a power supply unit for an aerosol inhaler according to an embodiment of the present invention will be described. First of all, the aerosol inhaler equipped with the power supply unit will be described with reference toFIG.1andFIG.2. (Aerosol Inhaler) An aerosol inhaler1is a device for inhaling an aerosol containing a flavor added without combustion, and has a rod shape extending along a certain direction (hereinafter, referred to as the longitudinal direction A). The aerosol inhaler1includes a power supply unit10, a first cartridge20, and a second cartridge30which are arranged in the order along the longitudinal direction A. The first cartridge20can be attached to and detached from the power supply unit10. The second cartridge30can be attached to and detached from the first cartridge20. In other words, the first cartridge20and the second cartridge30can be individually replaced. (Power Supply Unit) The power supply unit10of the present embodiment includes a power supply12, a charging IC55, an MCU50, a switch19, a voltage sensor16, various sensors, and so on in a cylindrical power supply unit case11, as shown inFIG.3,FIG.4, andFIG.6. The power supply12is a chargeable secondary battery, an electric double-layer capacitor, or the like, and is preferably a lithium-ion battery. On a top part11aof the power supply unit case11positioned on one end side in the longitudinal direction A (the first cartridge (20) side), a discharging terminal41is provided. The discharging terminal41is provided so as to protrude from the top surface of the top part11atoward the first cartridge20, and is configured to be able to be electrically connected to a load21of the first cartridge20. Further, on a part of the top surface of the top part11ain the vicinity of the discharging terminal41, an air supply part42for supplying air to the load21of the first cartridge20is provided. On a bottom part11bof the power supply unit10positioned on the other end side in the longitudinal direction A (the opposite side to the first cartridge20), a charging terminal43able to be electrically connected to an external power supply60(seeFIG.6) capable of charging the power supply12is provided. The charging terminal43is provided on the side surface of the bottom part11b, such that, for example, at least one of USB terminals, micro USB terminals, and Lightning terminals can be connected thereto. However, the charging terminal43may be a power receiving part able to receive power from the external power supply60in a non-contact manner. In this case, the charging terminal43(the power receiving part) may be composed of a power receiving coil. The wireless power transfer system may be an electromagnetic induction type, or may be a magnetic resonance type. Also, the charging terminal43may be a power receiving part able to receive power from the external power supply60without any contact point. As another example, the charging terminal43may be configured such that at least one of USB terminals, micro USB terminals, and Lightning terminals can be connected thereto and the above-mentioned power receiving part is included therein. On the side surface of the top part11aof the power supply unit case11, an operation unit14which the user can operate is provided so as to face the opposite side to the charging terminal43. More specifically, the operation unit14and the charging terminal43are symmetric with respect to the point of intersection of a straight line connecting the operation unit14and the charging terminal43and the center line of the power supply unit10in the longitudinal direction A. The operation unit14is composed of a button type switch, a touch panel, or the like. In the vicinity of the operation unit14, an inhalation sensor15for detecting a puff action are provided. The charging IC55is disposed close to the charging terminal43, and performs control on charging of the power supply12with power which is input from the charging terminal43. The charging IC55includes a converter for converting direct current, which is applied from an inverter61or the like provided for converting alternating current into direct current on a charging cable which is connected to the charging terminal, into direct current having a different parameter, a voltmeter for measuring charging voltage VCHGwhich is supplied from the converter to the power supply12, an ammeter for measuring charging current ICHGwhich is supplied from the converter to the power supply12, a processor for controlling them, and so on. In this specification, the processor is more specifically an electric circuit configured by combining circuit elements such as semiconductor elements. The charging IC55selectively performs constant current charging (CC charging) for charging the power supply12by performing control such that the charging current ICHGbecomes constant, and constant voltage charging (CV charging) for charging the power supply12by performing control such that the charging voltage VCHGbecomes constant. The charging IC55charges the power supply12by CC charging, in the state where power-supply voltage VBattcorresponding to the amount of power stored in the power supply12is lower than a predetermined CV switch voltage, and charges the power supply12by CV charging, in the state where the power-supply voltage VBattis equal to or higher than the above-mentioned CV switch voltage. The MCU50is connected to various sensor devices, such as the inhalation sensor15for detecting a puff (inhaling) action, a voltage sensor16for measuring the power-supply voltage VBattof the power supply12, and a temperature sensor17for measuring the temperature of the power supply12, the operation unit14, a notifying unit45(to be described below), and a memory18for storing the number of puff actions, the time for which power has been applied to the load21, as shown inFIG.5, and performs a variety of control on the aerosol inhaler1. The MCU50is specifically a processor. Also, in the power supply unit case11, an air intake (not shown in the drawings) for taking in air is formed. The air intake may be formed around the operation unit14, or may be formed around the charging terminal43. (First Cartridge) As shown inFIG.3, the first cartridge20includes a reservoir23for storing an aerosol source22, the electric load21for atomizing the aerosol source22, a wick24for drawing the aerosol source from the reservoir23toward the load21, an aerosol channel25for an aerosol generated by atomizing the aerosol source22to flow toward the second cartridge30, an end cap26for storing a part of the second cartridge30. The reservoir23is formed so as to surround the aerosol channel25, and holds the aerosol source22. In the reservoir23, a porous member such as a resin web or cotton may be stored, and the porous member may be impregnated with the aerosol source22. The aerosol source22includes a liquid such as glycerin, propylene glycol, or water. The wick24is a liquid holding member for drawing the aerosol source22toward the load21using capillarity, and is configured with, for example, glass fiber, a porous ceramic, or the like. The load21atomizes the aerosol source22without combustion by power which is supplied from the power supply12through the discharging terminal41. The load21is configured with a heating wire wound with a predetermined pitch (a coil). However, the load21needs only to be an element capable of atomizing the aerosol source22, thereby generating an aerosol, and is, for example, a heating element or an ultrasonic wave generator. Examples of the heating element include a heating resistor, a ceramic heater, an induction heating type heater, and so on. The aerosol channel25is provided on the downstream side of the load21on the center line L of the power supply unit10. The end cap26includes a cartridge storage part26afor storing a part of the second cartridge30, and a connecting passage26bfor connecting the aerosol channel25and the cartridge storage part26a. (Second Cartridge) The second cartridge30holds a flavor source31. The end part of the second cartridge30on the first cartridge (20) side is stored in the cartridge storage part26aprovided in the end cap26of the first cartridge20, so as to be able to be removed. The end part of the second cartridge30on the opposite side to the first cartridge (20) side is configured as an inhalation port32for the user. However, the inhalation port32does not necessarily need to be configured integrally with the second cartridge30so as not to be separable from the second cartridge, and may be configured to be able to be attached to and detached from the second cartridge30. If the inhalation port32is configured separately from the power supply unit10and the first cartridge20as described above, it is possible to keep the inhalation port32sanitary. The second cartridge30adds a flavor to the aerosol generated by atomizing the aerosol source22by the load21, by passing the aerosol through the flavor source31. As a raw material piece which constitutes the flavor source, a compact made by forming shredded tobacco or a tobacco raw material into a grain shape can be used. The flavor source31may be configured with a plant (such as mint or a herbal medicine, or a herb) other than tobacco. To the flavor source31, a flavoring agent such as menthol may be added. The aerosol inhaler1of the present embodiment can generate an aerosol containing the flavor by the aerosol source22, the flavor source31, and the load21. In other words, the aerosol source22and the flavor source31constitute an aerosol generation source for generating an aerosol. The aerosol generation source in the aerosol inhaler1is a part which the user can replace to use. For this part, for example, one first cartridge20and one or more (for example, five) second cartridges30can be provided as one set to the user. The configuration of the aerosol generation source which can be used in the aerosol inhaler1is not limited to the configuration in which the aerosol source22and the flavor source31are configured separately, and may be a configuration in which the aerosol source22and the flavor source31are formed integrally, a configuration in which the flavor source31is omitted and the aerosol source22contains a substance which can be contained in the flavor source31, a configuration in which the aerosol source22contains a medical substance or the like instead of the flavor source31, or the like. For an aerosol inhaler1including an aerosol generation source configured by integrally forming an aerosol source22and a flavor source31, for example, one or more (for example, 20) aerosol generation sources may be provided as one set to the user. In the case of an aerosol inhaler1including only an aerosol source22as an aerosol generation source, for example, one or more (for example, 20) aerosol generation sources may be provided as one set to the user. In the aerosol inhaler1configured as described above, as shown by an arrow B inFIG.3, air entering from the intake (not shown in the drawings) formed in the power supply unit case11passes through the air supply part42, and passes near the load21of the first cartridge20. The load21atomizes the aerosol source22drawn from the reservoir23by the wick24. The aerosol generated by atomizing flows through the aerosol channel25together with the air entering from the intake, and is supplied to the second cartridge30through the connecting passage26b. The aerosol supplied to the second cartridge30passes through the flavor source31, whereby the flavor is added, and is supplied to the inhalation port32. Also, in the aerosol inhaler1, a notifying unit45for notifying a variety of information is provided (seeFIG.5). The notifying unit45may be configured with a light emitting element, or may be configured with a vibrating element, or may be configured with a sound output element. The notifying unit45may be a combination of two or more elements of light emitting elements, vibrating elements, and sound output elements. The notifying unit45may be provided in any one of the power supply unit10, the first cartridge20, and the second cartridge30; however, it is preferable that the notifying unit be provided in the power supply unit10. For example, the area around the operation unit14is configured to have translucency to permit light which is emitted by a light emitting element such as an LED to pass through. (Electronic Circuit) Now, the details of the electric circuit of the power supply unit10will be described with reference toFIG.6. The power supply unit10includes the power supply12, a positive electrode side discharging terminal41aand a negative electrode side discharging terminal41bwhich constitute the discharging terminal41, a positive electrode side charging terminal43aand a negative electrode side charging terminal43bwhich constitute the charging terminal43, the MCU (Micro Controller Unit)50which is connected between the positive electrode side of the power supply12and the positive electrode side discharging terminal41aand between the negative electrode side of the power supply12and the negative electrode side discharging terminal41b, the charging IC55which is disposed on the power transmission path between the charging terminal43and the power supply12, and a switch19which is disposed on the power transmission path between the power supply12and the discharging terminal41. The switch19is configured with, for example, a semiconductor element such as a MOSFET, and is opened and closed by control of the MCU50. The MCU50has a function of detecting that the external power supply60is connected to the charging terminal43, on the basis of variation in the voltage between the MCU and the charging terminal43. In the electric circuit of the power supply unit10shown inFIG.6, the switch19is provided between the positive electrode side of the power supply12and the positive electrode side discharging terminal41a. Instead of this so-called plus control type, the switch19may be a minus control type which is provided between the negative electrode side discharging terminal41band the negative electrode side of the power supply12. (MCU) Now, the configuration of the MCU50will be described in more detail. As shown inFIG.5, the MCU50includes an aerosol generation request detecting unit51, an operation detecting unit52, a power control unit53, and a notification control unit54as functional blocks which are implemented by executing a program. The aerosol generation request detecting unit51detects a request for aerosol generation on the basis of the output result of the inhalation sensor15. The inhalation sensor15is configured to output the value of a variation in the pressure in the power supply unit10(the internal pressure) caused by inhalation of the user through the inhalation port32. The inhalation sensor15is, for example, a pressure sensor for outputting an output value (for example, a voltage value or a current value) according to the internal pressure which varies according to the flow rate of air which is sucked from the intake (not shown in the drawings) toward the inhalation port32(i.e. a puff action of the user). The inhalation sensor15may be configured with a capacitor microphone or the like. The operation detecting unit52detects an operation which is performed on the operation unit14by the user. The notification control unit54controls the notifying unit45such that the notifying unit notifies a variety of information. For example, the notification control unit54controls the notifying unit45in response to detection of a timing to replace the second cartridge30, such that the notifying unit notifies the timing to replace the second cartridge30. The notification control unit54detects and notifies a timing to replace the second cartridge30, on the basis of the number of puff actions and the cumulative time for which power has been supplied to the load21, stored in the memory18. The notification control unit54is not limited to notification of a timing to replace the second cartridge30, and may notify a timing to replace the first cartridge20, a timing to replace the power supply12, a timing to charge the power supply12, and so on. In the state where one unused second cartridge30is set, if a predetermined number of puff actions are performed, or if the cumulative time for which power has been applied to the load21due to puff actions reaches a predetermined value (for example, 120 seconds), the notification control unit54determines that the second cartridge30is used up (i.e. the remaining amount is zero or the second cartridge is empty), and notifies the timing to replace the second cartridge30. Also, in the case of determining that all of the second cartridges30included in one set are used up, the notification control unit54may determine that one first cartridge20included in the single set is used up (i.e. the remaining amount is zero or the first cartridge is empty), and notify the timing to replace the first cartridge20. Also, the notification control unit54calculates the state of charge (SOC) indicating the ratio of the amount of power stored in the power supply12(the amount of stored power) to the capacity (full charge capacity) of the power supply12(in percentages), as a numerical index indicating the state of charge of the power supply12, and controls the notifying unit45such that the notifying unit notifies the calculated SOC. The notification control unit54determines, for example, which of a first range equal to or larger than 0% and smaller than 33%, a second range equal to or larger than 33% and smaller than 66%, and a third range equal to or larger than 66% and smaller than 100% the SOC belongs to. Further, depending on the case where the SOC is in the first range, the case where the SOC is in the second range, and the case where the SOC is in the third range, the notification control unit54performs control, for example, turning on or flashing light emitting elements included in the notifying unit45in different colors, turning on or flashing light emitting elements included in the notifying unit45in different patterns, changing the number of light emitting elements to be turned on or flashed, of a plurality of light emitting elements included in the notifying unit45, changing the output sound of a sound output element of the notifying unit45, or changing the vibration pattern of a vibrating element of the notifying unit45. Therefore, the user of the aerosol inhaler1can intuitively the magnitude of the SOC of the power supply12by sound, color, or vibration, not by characters or an image which is displayed on a display or the like. If the notification control unit54notifies the SOC in the above-mentioned way, even if charging stop control to be described below is performed, as compared to the case of directly displaying the value of the SOC, it is possible to effectively reduce a feeling of strangeness which the user feels. The power control unit53controls discharging of the power supply12through the discharging terminal41by switching on and off the switch19if the aerosol generation request detecting unit51detects the request for aerosol generation. The power control unit53performs control such that the amount of aerosol which is generated by atomizing the aerosol source by the load21falls in a desired range, i.e. such that the amount of power which is supplied from the power supply12to the load21falls in a predetermined range. Specifically, the power control unit53controls switching on and off of the switch19by, for example, PWM (Pulse Width Modulation) control. Alternatively, the power control unit53may control switching on and off of the switch19by PFM (Pulse Frequency Modulation) control. The power control unit53stops supply of power from the power supply12to the load21if a predetermined period passes after start of supply of power to the load21. In other words, even while the user is actually performing a puff action, if the puff period exceeds a certain period, the power control unit53stops supply of power from the power supply12to the load21. The certain period is determined to suppress variation in user's puff period. By control of the power control unit53, the current which flows in the load21during one puff action becomes substantially a constant value which is determined according to substantially constant effective voltage which is supplied to the load21by PWM control, and the resistance values of the discharging terminal41and the load21. In the aerosol inhaler1of the present embodiment, when the user inhales an aerosol using one unused second cartridge30, the cumulative time for which power can be supplied to the load21is controlled to a maximum of, for example, 120 seconds. Therefore, in the case where one first cartridge20and five second cartridges30constitute one set, it is possible to obtain the maximum amount of power required to empty (use up) the single set, in advance. Also, the power control unit53detects an electric connection between the charging terminal43and the external power supply60. Then, in the state where charging of the power supply12is being performed by the charging IC55, the power control unit53performs control for stopping charging of the power supply12if the SOC of the power supply12becomes a value smaller than 100% (for example, an arbitrary value equal to or smaller than 95% or 90%), such that the power supply12does not become the fully charged state. By this control, the power supply12is maintained in the state where it is unlikely to deteriorate. In the case of using a lithium-ion secondary battery or the like as the power supply12, the SOC value when the power supply12is left as it is exerts an influence on deterioration of the power supply12. This influence on deterioration increases as the SOC gets closer to 100% or 0%. Meanwhile, this influence on deterioration becomes minimum when the SOC is between 30% and 70%. Therefore, if the SOC of the power supply12is maintained at a value smaller than 100%, it is possible to maintain the state where the power supply12is unlikely to deteriorate. Also, the power control unit53performs charging stop control on the power supply12, such that power more than the amount of power required to be supplied to the load21in order to empty one unused set or a plurality of unused sets (hereinafter, two sets are assumed) which are provided to the user is stored in the power supply12. This makes it possible to use up one set or two sets of aerosol generation sources even if charging of the power supply12is completed before the power supply becomes the fully charged state. In other words, it is possible to achieve both of suppression of deterioration of the power supply12and improvement of user convenience. Hereinafter, the amount of power required to be supplied to the load21in order to empty one set of unused aerosol generation sources will be referred to as the amount of necessary power for one set, and the amount of power required to be supplied to the load21in order to empty two sets of unused aerosol generation sources will be referred to as the amount of necessary power for two sets. (Charging Stop Control on Power Supply) In this control, during discharging control for discharging power from the power supply12to the load21, the MCU50stops discharging (in other words, the MCU prohibits discharging) when the SOC of the power supply12becomes 0%, and notifies the timing to charge the power supply12by the notifying unit45. Meanwhile, the MCU50determines an upper-limit-side arbitrary range (for example, a range between 90% and 95%) of an SOC range in which the power supply12is unlikely to deteriorate, in advance, and controls the charging IC55such that the charging IC completes charging of the power supply12, if the SOC of the power supply12reaches a specific value in that range in the course of charging of the power supply12by the charging IC55. Hereinafter, the SOC of the power supply12when the MCU50completes charging of the power supply12will be referred to as the charging stop SOC. As the power supply12, a high-capacity power supply is used such that the amount of stored power corresponding to the minimum value (90%) of the SOC in the above-mentioned arbitrary range is equal to or larger than the amount of necessary power for two sets. As a result, in the state where deterioration of the power supply12is less, even if control for stopping charging of the power supply12in the state where the SOC is 90% is performed, discharging for using up two sets of aerosol generation sources is possible. Therefore, even though the power supply12is not charged to the fully charged state (in which the SOC is 100%), user convenience is not damaged. FIG.7,FIG.8, andFIG.9are views illustrating examples of the relation between the full charge capacity of the power supply12in each of the cases different in the health state of the power supply12and the amount of power stored in the power supply when charging is completed. Hereinafter, as a numerical index indicating the healthy state of the power supply12, the state of health (SOH) will be described. The SOH is a numeric value which is obtained by dividing the full charge capacity of the power supply12when it is in a deteriorated state by the full charge capacity of the power supply12when it is brand new and multiplying the quotient by 100, and its unit is %. In other words, in the case where the SOH is a numerical index indicating the healthy state of the power supply12, a larger SOH value means that the state of the power supply12is closer to that of a brand new, and a smaller SOH value means deterioration of the power supply12has progressed more. The SOH can be measured or estimated by various methods. Also, the SOH can be defined as a numeric value which is obtained by dividing the internal resistance value of the power supply12when it is in a deteriorated state by the internal resistance value of the power supply12when it is brand new and multiplying the quotient by 100. In this case, the SOH is a numerical index indicating the deteriorated state of the power supply12. In the case where the SOH is a numerical index indicating the deteriorated state of the power supply12, a larger SOH value means that deterioration of the power supply12has progressed more, and a smaller SOH value means that the state of the power supply12is closer to that of a brand new. Hereinafter, the case where the SOH is a numerical index indicating the healthy state of the power supply12will be described as an example. Those skilled in the art could understand that even in the case where the SOH is a numerical index indicating the deteriorated state of the power supply12, similarly, the relation between the full charge capacity of the power supply12and the amount of power stored in the power supply12when charging is completed can be defined. InFIG.7, an example of the full charge capacity in the state where the SOH is 100%, i.e. the power supply12is brand new and the amount of stored power when charging is completed is shown. As described above, in the state where the SOH is 100%, capacity which is 90% of the full charge capacity of the power supply12is equal to or larger than the amount of necessary power for two sets. For this reason, in this state, the MCU50sets the charging stop SOC to 90% which is such a lower limit value that deterioration of the power supply12is suppressed, and completes charging when the SOC of the power supply12reaches 90%. InFIG.8, a state where the SOH is equal to or smaller than a threshold TH1smaller than 100% is shown. In other words, inFIG.8, a state where deterioration of the power supply12has further progressed as compared to the example ofFIG.7is shown. In the example ofFIG.8, capacity which is 90% of the full charge capacity of the power supply12is smaller than the amount of necessary power for two sets. In this state, the MCU50may set the charging stop SOC to, for example, 93% larger than 90%, such that when charging is completed, the amount of necessary power for two sets is secured as the amount of power stored in the power supply12, and complete charging when the SOC of the power supply12reaches 93%. In this case, even if the SOH slightly decreases, when charging is completed, sufficient power to empty two sets of aerosol generation sources is secured. InFIG.9, a state where the SOH is equal to or smaller than a threshold TH2smaller than the threshold TH1is shown. In other words, inFIG.9, a state where deterioration of the power supply12has further progressed as compared to the example ofFIG.8is shown. In the example ofFIG.9, the full charge capacity of the power supply12is equal to or smaller than the amount of necessary power for two sets. In this state, the MCU50sets the charging stop SOC to any one value between 90% and 95%, such that when charging is completed, the amount of necessary power for one set is secured as the amount of power stored in the power supply12, and completes charging when the SOC of the power supply12reaches the set value. In this case, even if the SOH significantly decreases, when charging is completed, sufficient power to empty one set of aerosol generation sources is secured. Also, the MCU50may detect deterioration of the power supply12in response to change of the SOH to a value equal to or smaller than the threshold TH2, and notify that the power supply12has deteriorated, by the notifying unit45. Alternatively, the MCU50may start the above-mentioned charging stop control on the power supply12in response to change of the SOH to a value equal to or smaller than the threshold TH2. In this way, it is possible to suppress further deterioration of the deteriorated power supply12. Also, until deterioration of the power supply12is detected, or until the charging stop control on the power supply12is started, in the power supply12, sufficient power to empty one set of aerosol generation sources is secured. Therefore, user convenience further improves. Hereinafter, the charging stop control which the MCU50performs will be described specifically. First of all, the MCU50measures or estimates the SOH, and estimates the full charge capacity of the power supply12from the SOH. In measuring or estimating the SOH, the internal resistance of the power supply12, the integrated value of power stored and discharged, and so on may be used. Specifically, by multiplying the known full charge capacity of the power supply12when it is brand new by the SOH, the current full charge capacity is estimated. In the case where the value obtained by multiplying the estimated full charge capacity by the lower limit value (90%) for the charging stop SOC is equal to or larger than the amount of necessary power for two sets (the case ofFIG.7), the MCU50sets the charging stop SOC to 90% which is the lower limit value. In this way, in the state where deterioration of the power supply12is less, it is possible to secure power for consume two sets by performing charging once while effectively suppressing deterioration of the power supply12. In the case where the value obtained by multiplying the estimated full charge capacity by the lower limit value (90%) for the charging stop SOC becomes smaller than the amount of necessary power for two sets, and the value obtained by multiplying the estimated full charge capacity by the upper limit value (95%) for the charging stop SOC becomes equal to or larger than the amount of necessary power for two sets (the case ofFIG.8), the MCU50sets such an SOC value (a value larger than 90%) that when charging is completed, the amount of necessary power for two sets can be secured as the amount of power stored in the power supply12, as the charging stop SOC. Even in this case, since the power supply does not become the fully charged state, it is possible to secure power for consume two sets while suppressing deterioration. In the case where each of the values obtained by multiplying the estimated full charge capacity by the lower limit value (90%) and upper limit value (95%) for the charging stop SOC is smaller than the amount of necessary power for two sets, the MCU50determines such charging stop SOC that the amount of stored power when charging is stopped, the amount of necessary power for one set or more can be secured as the amount of stored power, from the range between 90% and 95%. As a result, it is possible to secure power for consuming one set while suppressing deterioration of the power supply12. In the case where the value obtained by multiplying the estimated full charge capacity by the upper limit value (95%) for the charging stop SOC is smaller than the amount of necessary power for one set, the MCU50controls the notifying unit45such that the notifying unit notifies the user that the timing has come to replace the power supply12. When the amount of stored charge which is obtained by subtracting the amount of power stored in the power source12when discharging of the power supply12is prohibited (when SOC is 0%) from the amount of power stored in the power source12when charging is completed is defined as a discharging permission power amount, by the above-described control of the MCU50, it is possible to set an amount equal to or larger than the amount of necessary power for one set or two sets, as the discharging permission power amount. Therefore, not only in the state where the power supply12is brand new but also in the state where deterioration has progressed, it is possible to consume at least one set of aerosol generation sources. Therefore, it is possible to improve convenience. Also, since the power supply12does not become the fully charged state, it is possible to suppress deterioration. In the above-described embodiment, the MCU50determines the charging stop SOC with reference to the amount of necessary power for two sets. Alternatively, the MCU50may determine the charging stop SOC with reference to the amount of necessary power for one set. In this case, in any deteriorated (healthy) state, the charging stop SOC is set to the lower limit value (90%). Also, it should be noted that the lower limit value (90%) and upper limit value (95%) for the charging stop SOC described in the above embodiment are merely an example. Since they are values depending on each power supply12which is used, it is preferable that they be obtained by experiments on individual power supplies12, and so on. (First Modification of Charging Stop Control on Power Supply) In this control, during charging of the power supply12, the MCU50completes charging when the SOC of the power supply12becomes 100%. Meanwhile, the MCU50determines a lower-limit-side arbitrary range (for example, a range between 10% and 5%) of an SOC range in which the power supply12is unlikely to deteriorate, in advance, and stops discharging of power from the power supply12to the load21(in other words, the MCU prohibits discharging) in the case where the SOC of the power supply12reaches a specific value in the determined range in the course of discharging of power from the power supply12to the load21, and notifies the timing to charge the power supply12by the notifying unit45. Hereinafter, the SOC of the power supply12when the MCU50prohibits discharging of the power supply12will be referred to as the discharging prohibition SOC. As the power supply12, a high-capacity power supply is used such that capacity obtained by subtracting the amount of stored power corresponding to the maximum value (which is 10%) for the SOC in the arbitrary range from the full charge capacity becomes equal to or larger than t the amount of necessary power for two sets (in other words, the capacity which is 90% of the full charge capacity of the power supply12becomes equal to or larger than the amount of necessary power for two sets). As a result, in the state where deterioration of the power supply12is less, even if control for prohibiting discharging of the power supply12in the state where the SOC is 10% is performed, discharging for emptying two sets of aerosol generation sources is possible. FIG.10,FIG.11, andFIG.12are views illustrating examples of the relation between the full charge capacity of the power supply12in each of the cases different in the healthy state of the power supply12and the amount of power stored in the power supply12when discharging is prohibited. InFIG.10, an example of the full charge capacity in the state where the SOH is 100%, i.e. the power supply12is brand new and the amount of stored power when discharging is prohibited is shown. As described above, in the state where the SOH is 100%, the capacity which is 90% of the full charge capacity of the power supply12becomes equal to or larger than the amount of necessary power for two sets. For this reason, in this state, the MCU50sets the discharging prohibition SOC to 10% of the upper limit value at which deterioration of the power supply12is minimized, and prohibits discharging when the SOC of the power supply12reaches 10%. InFIG.11, a state where the SOH is equal to or smaller than the threshold TH1smaller than 100% is shown. In other words, inFIG.11, the state where deterioration of the power supply12has further progressed as compared to the example ofFIG.10is shown. In the example ofFIG.11, the capacity which is 90% of the full charge capacity of the power supply12becomes smaller than the amount of necessary power for two sets. In this state, the MCU sets the discharging prohibition SOC to, for example, 7% smaller than 10% such that the difference between the full charge capacity and the amount of power stored in the power supply12when discharging is stopped becomes the amount of necessary power for two sets, and prohibits discharging of the power supply12when the SOC of the power supply12reaches 7%. In this case, even if the SOH slightly decreases, when charging is completed, sufficient power to empty two sets of aerosol generation sources is secured. InFIG.12, a state where the SOH is equal to or smaller than the threshold TH2smaller than the threshold TH1is shown. In other words, inFIG.12, a state where deterioration of the power supply12has further progressed as compared to the example ofFIG.11is shown. In the example ofFIG.12, the full charge capacity of the power supply12is equal to or smaller than the amount of necessary power for two sets. In this state, the MCU50sets the discharging prohibition SOC to any one value between 10% and 5% such that the difference between the full charge capacity and the amount of power stored in the power supply12when discharging is stopped becomes equal to or larger than the amount of necessary power for one set, and prohibits discharging when the SOC of the power supply12reaches the set value. In this case, even if the SOH significantly decreases, when charging is completed, sufficient power to empty one set of aerosol generation sources is secured. Also, the MCU50may detect deterioration of the power supply12in response to change of the SOH to a value equal to or smaller than the threshold TH2, and notify that the power supply12has deteriorated, by the notifying unit45. Alternatively, the MCU50may start the above-mentioned discharging stop control on the power supply12in response to change of the SOH to a value equal to or smaller than the threshold TH2. In this way, it is possible to suppress further deterioration of the deteriorated power supply12. Also, until deterioration of the power supply12is detected, or until the discharging stop control on the power supply12is started, in the power supply12, sufficient power to empty one set of aerosol generation sources is secured. Therefore, user convenience further improves. Hereinafter, the discharging stop control which the MCU50performs will be described specifically. First of all, the MCU50measures or estimates the SOH, and estimates the full charge capacity of the power supply12from the SOH. In measuring or estimating the SOH, the internal resistance of the power supply12, the integrated value of power stored and discharged, and so on may be used. Specifically, by multiplying the known full charge capacity of the power supply12when it is brand new by the SOH, the current full charge capacity is estimated. In the case where capacity which is obtained by multiplying the full charge capacity estimated in the above-mentioned way by the upper limit value (10%) for the discharging prohibition SOC and subtracting the result value from the estimated full charge capacity is equal to or larger than the amount of necessary power for two sets (the case ofFIG.10), the MCU50sets the discharging prohibition SOC to 10% which the upper limit value. In this way, in the state where deterioration of the power supply12is less, it is possible to secure power for consume two sets by performing charging once while effectively suppressing deterioration of the power supply12. In the case where the capacity which is obtained by multiplying the estimated full charge capacity by the lower limit value (5%) for the discharging prohibition SOC and subtracting the result value from the estimated full charge capacity becomes equal to or larger than the amount of necessary power for two sets, and the capacity which is obtained by multiplying the estimated full charge capacity by the upper limit value (10%) for the discharging prohibition SOC and subtracting the result value from the estimated full charge capacity becomes smaller than the amount of necessary power for two sets (the case ofFIG.11), the MCU sets such an SOC value (a value smaller than 10%) that capacity which is obtained by subtracting the amount of power stored in the power supply12when discharging is prohibited from the full charge capacity becomes the amount of necessary power for two sets, as the discharging prohibition SOC. Even in this case, since the power supply does not become the discharging termination state, it is possible to secure power for consume two sets while suppressing deterioration. In the case where each of the capacity which is obtained by multiplying the estimated full charge capacity by the lower limit value (5%) for the discharging prohibition SOC and subtracting the result value from the estimated full charge capacity, and the capacity which is obtained by multiplying the estimated full charge capacity by the upper limit value (10%) the discharging prohibition SOC and subtracting the result value from the estimated full charge capacity becomes smaller than the amount of necessary power for two sets (the case ofFIG.12), the MCU determines such a value that the capability which is obtained by subtracting the amount of power stored in the power supply12when discharging is prohibited from the full charge capacity becomes the amount of necessary power for one set, as the discharging prohibition SOC from the range between 10% and 5%. As a result, it is possible to secure power for consuming one set while suppressing deterioration of the power supply12. In the case where the capacity which is obtained by multiplying the estimated full charge capacity by the lower limit value (5%) for the discharging prohibition SOC and subtracting the result value from the estimated full charge capacity becomes smaller than the amount of necessary power for one set, the MCU50controls the notifying unit45such that the notifying unit notifies the user that the timing has come to replace the power supply12. When the amount of stored power obtained by subtracting the amount of power stored in the power source12when discharging of the power supply12is prohibited from the amount of power stored in the power source12when charging is completed is defined as the discharging permission power amount, by the above-described discharging stop control of the MCU50, it is possible to set an amount equal to or larger than the amount of necessary power for one set or two sets, as the discharging permission power amount. Therefore, not only in the state where the power supply12is brand new but also in the state where deterioration has progressed, it is possible to consume at least one set of aerosol generation sources. Therefore, it is possible to improve convenience. Also, since the power supply12does not become the discharging termination state, it is possible to suppress deterioration. In the above-described embodiment, the MCU50determines the discharging prohibition SOC with reference to the amount of necessary power for two sets. Alternatively, the MCU50may determine the discharging prohibition SOC with reference to the amount of necessary power for one set. In this case, in any deteriorated (healthy) state, the discharging prohibition SOC is set to the upper limit value (10%). Also, it should be noted that the lower limit value (5%) and upper limit value (10%) for the discharging prohibition SOC described in the above embodiment are merely an example. Since they are values depending on each power supply12which is used, it is preferable that they are obtained by experiments on individual power supplies12, and so on. (Second Modification of Charging Stop Control on Power Supply) The MCU50may perform control for completing charging when the SOC of the power supply12becomes the specific value in the upper-limit-side arbitrary range, in the course of charging of the power supply12, and prohibiting discharging when the SOC of the power supply12becomes the specific value in the lower-limit-side arbitrary range, in the course of discharging of the power supply12. In other words, the MCU50may control each of charging and discharging of the power supply12such that the power supply12does not become any of the fully charged state and the discharging termination state. When the amount of stored power which is obtained by subtracting the amount of power stored in the power source12when discharging of the power supply12is prohibited from the amount of power stored in the power source12when charging is completed is defined as the discharging permission power amount, the MCU50sets each of the charging stop SOC and the discharging prohibition SOC, such that the discharging permission power amount becomes the amount of necessary power for one set or two sets. In this case, not only in the state where the power supply12is brand new but also in the state where deterioration has progressed, it becomes possible to consume at least one set of aerosol generation sources. Therefore, it is possible to improve convenience. Also, since the power supply12does not become any of the fully charged state and the discharging termination state, it is possible to further suppress deterioration. (Third Modification of Charging Stop Control on Power Supply) Charging stop control which is performed in the case where one set composed of one first cartridge20and a plurality of (for example, five) second cartridges30is provided as aerosol generation sources to the user will be described below. In this case, in order to empty one brand new (unused) first cartridge20, it is required to empty five brand new (unused) second cartridges30. The amount of necessary power may be set on the basis of the amount of power required to consume one brand new (unused) first cartridge20, or may be set on the basis of the amount of power required to consume one brand new (unused) second cartridge30. In the case of setting the amount of necessary power on the basis of the amount of power required to consume one brand new (unused) first cartridge20, the power supply12has sufficient power to consume one set. Therefore, it is possible to prevent the frequency of charging of the power supply12from excessively increasing while suppressing deterioration of the power supply12. In the case of setting the amount of necessary power on the basis of the amount of power required to consume one brand new (unused) second cartridge30, it is possible to reduce the size, weight, and cost of the power supply12. In the above description, the MCU50controls at least one of the charging stop SOC and the discharging prohibition SOC. However, of this control, the control on the charging stop SOC may be performed by the charging IC55. In this specification, at least the following inventions (1) to (14) are disclosed. (1) A power supply unit for an aerosol inhaler comprising: a power supply that is able to discharge power to a load for generating an aerosol from an aerosol generation source; and a control unit that is configured to control at least one of charging and discharging of the power supply such that the power supply does not become one or both of a fully charged state and a discharging termination state. According to (1), since the power supply is controlled such that the power supply does not become one or both of the fully charged state and the discharging termination state, it is possible to suppress deterioration of the power supply. Especially, in devices which can be frequently used and be charged and discharged, like aerosol inhalers, by performing such control, it is possible to suppress deterioration of their power supplies, thereby extending the lives of the devices. In addition, it is possible to obtain energy saving effect. (2) The power supply unit according to (1), wherein a remainder which is obtained by subtracting an amount of power stored in the power supply to cause the discharging to be prohibited from an amount of power stored in the power supply in a state where the charging is completed is defined as a discharging permission power amount, and the control unit controls at least one of the charging and the discharging of the power supply such that the discharging permission power amount becomes equal to or larger than an amount of power required to be supplied to the load in order to empty the aerosol generation source which is unused. According to (2), in the state where the charging of the power supply is completed, it becomes possible to consume the unused aerosol generation source by the aerosol inhaler. Therefore, it is possible to prevent a situation in which it becomes impossible to generate an aerosol in the state where there is the remaining amount of the aerosol generation source, and it is possible to prevent frequent charging of the power supply, thereby suppressing deterioration of the power supply. In other words, it is possible to achieve both of suppression of deterioration of the power supply and improvement of user convenience. (3) The power supply unit according to (2), wherein the aerosol generation source includes a first unit containing a medium to be atomized by the load, and a second unit containing a flavor source to add a flavor to the atomized medium, and the control unit controls at least one of the charging and the discharging of the power supply such that the discharging permission power amount becomes equal to or larger than an amount of power required to be supplied to the load in order to empty a predetermined number, which is one or more, of the first unit. According to (3), in the state where the charging of the power supply is completed, it becomes possible to consume the predetermined number of the first unit by the aerosol inhaler. For example, in the case where a plurality of second units can be used by one first unit, it becomes possible to consume many second units by performing charging once. Therefore, it is possible to prevent frequent charging of the power supply, thereby suppressing deterioration of the power supply. (4) The power supply unit according to (2), wherein the aerosol generation source includes a first unit containing a medium to be atomized by the load, and a second unit containing a flavor source to add a flavor to the atomized medium, and the control unit controls at least one of the charging and the discharging of the power supply such that the discharging permission power amount becomes equal to or larger than an amount of power required to be supplied to the load in order to empty a predetermined number, which is one or more, of the second unit. According to (4), in the state where the charging of the power supply is completed, it becomes possible to consume the predetermined number of the second unit by the aerosol inhaler. For example, a configuration in which the discharging permission power amount of the power supply becomes equal to or larger than the amount of power required to empty a plurality of second units can be made to make it possible to consume many second units by performing charging once. In this case, it is possible to prevent frequent charging of the power supply, thereby suppressing deterioration of the power supply. Also, by making a configuration in which the discharging permission power amount of the power supply becomes equal to or larger than the amount of power required to empty, for example, one second unit, it is possible to reduce the capacity of the power supply, and it is possible to reduce the size, weight, and cost of the aerosol inhaler. Also, since it is possible to make the amount of power for consuming one second unit smaller than the amount of power for consuming one first unit, it is possible to reduce the capacity of the power supply, and it is possible to reduce the size, weight, and cost of the aerosol inhaler. (5) An aerosol inhaler comprising: the power supply unit according to (3) or (4); the first unit; and the second unit that is emptied more quickly than the first unit which is unused if discharging of power to the load is performed when the second unit is unused. (6) The power supply unit according to (1), wherein a remainder which is obtained by subtracting an amount of power stored in the power supply to cause the discharging to be prohibited from an amount of power stored in the power supply in a state where the charging is completed is defined as a discharging permission power amount, and the control unit controls at least one of the charging and the discharging of the power supply such that the discharging permission power amount in a first state where a numerical index indicating a state where the charging of the power supply is completed and a deteriorated state of the power supply is smaller than a threshold or a numerical index indicating a healthy state of the power supply is equal to or larger than a threshold becomes equal to or larger than an amount of power required to be supplied to the load in order to empty the aerosol generation source which is unused. According to (5), in the state where deterioration of the power supply has not progressed, the discharging permission power amount equal to or larger than the amount of power required to be supplied to the load in order to empty the aerosol generation source unused is secured. Therefore, even if the deterioration of the power supply progresses, it is possible to secure sufficient power to empty the unused aerosol generation source. Also, by reducing the discharging permission power amount in the above-mentioned state, it is possible to reduce the capacity of the power supply, and it is possible to reduce the size, weight, and cost of the aerosol inhaler. (7) The power supply unit according to (6), wherein the first state is a state of the power supply which is brand new. (8) The power supply unit according to (1), (6), or (7), wherein a remainder which is obtained by subtracting an amount of power stored in the power supply to cause the discharging to be prohibited from an amount of power stored in the power supply in a state where the charging is completed is defined as a discharging permission power amount, and the control unit controls at least one of the charging and the discharging of the power supply such that the discharging permission power amount in a second state where a numerical index indicating a state where charging of the power supply is completed and a deteriorated state of the power supply is equal to or larger than a threshold or a numerical index indicating a healthy state of the power supply is smaller than a threshold becomes equal to or larger than an amount of power required to be supplied to the load in order to empty the aerosol generation source which is unused. According to (8), even if deterioration of the power supply progresses, whereby the full charge capacity of the power supply decreases, the discharging permission power amount equal to or larger than the amount of power required to be supplied to the load in order to empty the unused aerosol generation source is secured. Therefore, it becomes possible to use up the unused aerosol generation source. Also, by reducing the discharging permission power amount in the above-mentioned state, it becomes possible to reduce the capacity of the power supply, and it is possible to reduce the size, weight, and cost of the aerosol inhaler. (9) The power supply unit according to (8), wherein the second state is a state where the control unit detects deterioration of the power supply or suppresses the charging and the discharging of the power supply. (10) The power supply unit according to any one of (1) to (9), wherein the control unit performs the charging of the power supply such that the power supply does not become the fully charged state. According to (10), it is possible to shorten the time required for completing the charging of the power supply. (11) The power supply unit according to (10), wherein the control unit performs the charging of the power supply such that an upper limit value for SOC indicating a ratio of an amount of power stored in the power supply to a full charge capacity of the power supply becomes equal to or smaller than 95%. According to (11), the capacity of the power supply is set to be large such that it is possible to supply power more than power required to empty the aerosol generation source to the load in a state where the SOC is 95%. Therefore, even if deterioration of the power supply progresses, whereby the capacity decreases, it is possible to secure power for consuming the aerosol generation source, and it is possible to extend the life of the aerosol inhaler. (12) The power supply unit according to (11), wherein the control unit performs the charging of the power supply such that the upper limit value for SOC indicating the ratio of the amount of power stored in the power supply to the full charge capacity of the power supply becomes equal to or smaller than 90%. According to (12), the capacity of the power supply is set to be large such that it is possible to supply power more than power required to empty the aerosol generation source to the load in a state where the SOC is 90%. Therefore, even if deterioration of the power supply progresses, whereby the capacity decreases, it is possible to secure power for consuming the aerosol generation source, and it is possible to extend the life of the aerosol inhaler. (13) A power supply control method of an aerosol inhaler, the aerosol inhaler including a power supply that is able to discharge power to a load for generating an aerosol from an aerosol generation source, the power supply control method comprising: a control step of controlling at least one of charging and discharging of the power supply such that the power supply does not become one or both of a fully charged state and a discharging termination state. (14) A power supply control program of an aerosol inhaler, the aerosol inhaler including a power supply that is able to discharge power to a load for generating an aerosol from an aerosol generation source, the power supply control program making a computer execute: a control step of controlling at least one of charging and discharging of the power supply such that the power supply does not become one or both of a fully charged state and a discharging termination state. According to (13) and (14), since the power supply is controlled such that the power supply does not become one or both of the fully charged state and the discharging termination state, it is possible to suppress deterioration of the power supply. Especially, in devices which can be frequently used and be charged and discharged, like aerosol inhalers, by performing such control, it is possible to suppress deterioration of their power supplies, thereby extending the lives of the devices. In addition, it is possible to obtain energy saving effect. According to (1), (13), and (14), since the power supply is controlled such that the power supply does not become one or any one of the fully charged state and the discharging termination state, it is possible to suppress deterioration of the power supply. Especially, in devices which can be frequently used and be charged and discharged, like aerosol inhalers, by performing such control, it is possible to suppress deterioration of their power supplies, thereby extending the lives of the devices. Therefore, there is energy saving effect in which it is possible to use the power supply for a long time without replacing with a brand new one. According to the present invention, it is possible to suppress deterioration in the performance of the power supply. | 61,321 |
11862998 | DESCRIPTION OF EMBODIMENTS First Embodiment FIG.1is a diagram illustrating a configuration of a battery management device according to a first embodiment of the present invention. The battery management device1illustrated inFIG.1manages m battery cells2connected in series, and is connected to the battery cells2and a lead storage battery7. Each battery cell2is configured by using a chargeable/dischargeable secondary battery, for example, a lithium ion battery. InFIG.1, the m battery cells2are represented by BC1to BCm, respectively, and lines connecting between the battery management device1and positive and negative electrodes of each battery cell2are represented by DO to Lm. The battery management device1includes a control unit3, cell controllers (hereinafter, abbreviated as “cell cons”)41and42, and an insulating means5. The cell cons41and42are respectively connected to a plurality of battery cells2, and have a function of measuring a voltage of each battery cell2and a function of controlling a discharge of each battery cell2and performing balancing to adjust the voltage of each battery cell2. Note that inFIG.1, the cell con42is connected to the battery cells2of BC1and BC2, the cell con41is connected to the battery cells2of BCm−1 and BCm, and a cell con connected to other battery cells2is not illustrated. However, in reality, the number of cell cons provided in the battery management device1or the number of battery cells2connected to each cell con is not limited to the example ofFIG.1and can be set arbitrarily. The control unit3has a function of acquiring cell voltage information regarding the voltage of each battery cell2measured by the cell cons41and42from the cell cons41and42, and controlling the cell cons41and42based on the acquired cell voltage information. Specifically, for example, the control unit3determines whether or not a voltage variation of each battery cell2is a predetermined value or more based on the cell voltage information. As a result, when it is determined that the voltage variation is the predetermined value or more, the control unit3sets a discharge time according to a voltage difference between the battery cell2having a relatively high voltage and other battery cells2, and instructs the cell cons41and42to discharge the battery cell2for the discharge time. According to the discharge instruction from the control unit3, the cell cons41and42perform balancing by performing discharge control of each battery cell2so that a specified battery cell2is discharged for a specified discharge time to reduce the voltage variation of each battery cell2. Further, the control unit3sets a balancing time instructing an execution time of balancing in the cell cons41and42, and transmits information on the set balancing time to the cell cons41and42together with the discharge instruction. When the balancing time instructed by the control unit3elapses, the cell cons41and42end balancing and automatically stop. The control unit3is connected to the lead storage battery7and operates by receiving power supply from the lead storage battery7. On the other hand, the cell cons41and42are not connected to the lead storage battery7and operate by receiving power supply from the battery cell2. The insulating means5is a means for insulating communication signals between the control unit3and the cell cons41and42. As the insulating means5, a well-known insulating method such as, for example, a photo coupler, a photo MOS relay, a pulse transformer, a digital isolator, a capacitor, and radio communication can be applied. The battery management device1can separate the lead storage battery7which is a power source of the control unit3and the battery cell2which is a power source of the cell cons41and42by having the insulating means5between the control unit3and the cell cons41and42. The cell cons41and42each include a start and stop circuit411, a main timer412, and a stop management unit413. Power for operating these is supplied from the battery cell2that supplies power to the cell cons41and42, and is power different from the lead storage battery7that supplies power to the control unit3. Note that since the cell cons41and42have the same function and configuration, the function and configuration of the cell con41will be described below, and the description of the cell con42will be omitted. The start and stop circuit411is a circuit that controls the start and stop of the cell con41. The main timer412measures an elapsed time after the cell con41starts balancing, and instructs the start and stop circuit411to stop the cell con41when a measurement result of the elapsed time reaches the balancing time instructed by the control unit3. That is, when the balancing is started in the cell con41, the main timer412measures the elapsed time for stopping the cell con41accordingly. The stop management unit413stops the cell con41and ends the balancing even when the main timer412cannot operate normally by instructing the start and stop circuit411to stop the cell con41when the main timer412is abnormal. The details of the stop management unit413will be described later. In the following, the operations of the control unit3and the cell con41when performing balancing when the battery management device1and the battery cell2are mounted on a vehicle such as a hybrid electric vehicle (HEV) or an electric vehicle (EV), and the vehicle is stopped will be described. Note that since the operation of the cell con42is the same as that of the cell con41, the description thereof will be omitted. When performing balancing, the control unit3transmits information for setting a balancing time to the main timer412to the cell con41together with a balancing instruction while the vehicle is stopped (key off), and then stops. By stopping the control unit3after setting the balancing time, the power consumption of the lead storage battery7during balancing is suppressed. However, at this time, the control unit3may not be completely stopped, and may continue to operate in a standby state so that it can be started immediately upon receiving a signal from the cell cons41and42or a host controller (not illustrated). That is, the control unit3has a normal operation mode in which power is supplied from the lead storage battery7and performs an operation such as setting of the balancing time, and a low power consumption mode in which power consumption is lower than the normal operation mode, and can selectively use these two modes according to the situation. When the balancing time is set by the control unit3together with the balancing instruction, the cell con41performs an operation such as balancing during the set balancing time, and then stops. At this time, the start and stop circuit411stops the cell con41according to an instruction from the main timer412or an instruction from the stop management unit413when the main timer412is abnormal. By stopping the cell con41after the balancing is performed in this way, the power consumption of the battery cell2after the balancing is suppressed. However, at this time, the cell con41may not be completely stopped like the control unit3and may continue to operate in a standby state so that it can be started immediately upon receiving a signal from the control unit3. In the battery management device1, since the control unit3and the cell cons41and42perform the operations described above, respectively, it is possible to perform balancing while the vehicle is stopped. Here, if it is attempted to perform balancing only while the vehicle is running, since it is not possible to secure a sufficient discharge time for equalizing the variation of each battery cell2within a limited time while the vehicle is running, balancing with a large current is required. However, in recent years, the capacity of the battery cell2has been increasing toward an increase of a mileage of the vehicle, and accordingly, a balancing current needs to be further increased. Since heat generation of the battery management device1increases as the balancing current increases, an appropriate heat dissipation structure or cooling structure is required. As a result, the convenience of the vehicle may be reduced due to an increase in size of the vehicle, or an electricity cost may be reduced due to an increase of a vehicle weight. On the other hand, according to the battery management device1of the present embodiment, since the balancing is possible even when the vehicle is stopped, it is possible to reduce the balancing current. Therefore, it is possible to solve the above-mentioned problems that occur during balancing while the vehicle is running. Note that in the present embodiment, the control unit3and the cell cons41and42are configured in the form illustrated inFIG.1so that the cell cons41and42can perform balancing both when the vehicle is running and when the vehicle is stopped. While the vehicle is running (key on), the control unit3may manage an execution time of balancing by transmitting a balancing ON command and a balancing OFF command to the cell cons41and42. In addition, the start and stop circuit411can stop the operation of the cell con41according to an instruction from the stop management unit413when the main timer412is abnormal. By doing so, even if the main timer412cannot operate normally due to a failure or the like, the cell con41can be stopped after the balancing is performed. Here, if the cell con41does not include the stop management unit413, since the cell con41cannot be stopped when the main timer412fails, the power consumption of the battery cell2is continued even after the balancing is performed. In the battery management device1of the present embodiment, by disposing the stop management unit413in the cell con41, it becomes possible to solve such a problem. Next, details of the cell con41including the stop management unit413will be described with reference toFIG.2.FIG.2is a diagram illustrating a configuration of the cell con41according to the first embodiment of the present invention. Although the configuration of the cell con41is illustrated inFIG.2, the cell con42has the same configuration as described above. As illustrated inFIG.2, the cell con41of the present embodiment includes a cell con IC410and a cell interface circuit417. The cell con IC410, which is a semiconductor integrated circuit, further includes a balancing timer414, a power supply circuit415, a communication circuit416, a balancing switch418, and a switch control circuit419, in addition to the start and stop circuit411, the main timer412, and the stop management unit413described above. Note that inFIG.2, each of these components was realized as a circuit inside the cell con IC410, but may be realized as a circuit separate from the cell con IC410. Alternatively, the cell con IC410may be configured using a plurality of semiconductor integrated circuits, and these components may be arranged in each semiconductor integrated circuit of the cell con IC410in an arbitrary distribution. The communication circuit416is connected to the control unit3ofFIG.1via a communication terminal Tcom, receives a communication signal transmitted from the control unit3, and outputs the communication signal to the start and stop circuit411and the switch control circuit419. The communication signal includes the above-mentioned balancing instruction or balancing time information transmitted from the control unit3when performing balancing. In addition, the communication circuit416acquires a voltage measurement result of each battery cell2measured by a voltage measurement circuit (not illustrated) and transmits the voltage measurement result to the control unit3. The power supply circuit415uses a voltage input from the battery cell2via a power supply terminal Tvcc to generate operating power of the cell con IC410. The start and stop circuit411can stop the entire cell con41by stopping the operation of the power supply circuit415after performing the balancing. The cell interface circuit417is a circuit that connects between each of the n battery cells2corresponding to the cell con41and the cell con IC410, and includes n+1 sets of balancing paths and voltage measurement paths connected to the positive electrode and the negative electrode of each battery cell2, respectively. That is, the cell interface circuit417includes n+1 balancing paths SW0to SWn, which are paths for balancing each battery cell2, and n+1 voltage measurement paths SL0to SLn, which are paths for measuring the voltage of each battery cell2. Note that, a ground line GND indicating a reference potential in the cell con41is connected in parallel to the balancing path SW0and the voltage measurement path SL0connected to the negative electrode of the battery cell2on the lowest potential side among the n battery cells2. The ground line GND is connected to a ground terminal Tg of the cell con IC410. Resistors RC and capacitors CC, which form an RC filter for removing noise, are arranged on the voltage measurement paths SL0to SLn, respectively. The positive electrode and the negative electrode of each battery cell2are connected to a voltage measurement circuit (not illustrated) included in the cell con IC410via the voltage measurement paths SL0to SLn and a voltage measurement terminal Ta of the cell con IC410. The voltage measurement circuit is configured using, for example, an AD converter, and can acquire a voltage measurement result between the positive and negative electrodes of each battery cell2as a digital value. The voltage measurement result acquired by the voltage measurement circuit is reported to the control unit3via the communication circuit416as described above. The control unit3can manage a state of each battery cell2by using a voltage value of each battery cell2represented by the voltage measurement result. Resistors RB and capacitors CB for adjusting the balancing current are arranged on the balancing paths SW0to SWn, respectively. The positive electrode and the negative electrode of each battery cell2can be connected to each other via the balancing paths SW0to SWn, a balancing terminal Tb and the balancing switch418of the cell con IC410. At the time of performing balancing, a balancing current flows from the positive electrode to the negative electrode of each battery cell2through the balancing paths SW0to SWn, so that each battery cell2is discharged. The balancing switch418is configured with n switches BSW1to BSWn corresponding to each battery cell2. The switches BSW1to BSWn are connected to the balancing paths SW0to SWn of the cell interface circuit417via the balancing terminals Tb, respectively. The switch control circuit419controls the balancing switch418according to the balancing instruction from the control unit3to discharge the battery cell2designated as a discharge target in the balancing instruction. Specifically, the switch control circuit419perform controls to turn on a switch corresponding to the battery cell2designated as the discharge target by the control unit3among the switches BSW1to BSWn in the balancing switch418. As a result, a balancing current flows through the resistor RB, the battery cell2is discharged, and the balancing is performed. Note that at this time, the plurality of battery cells2may be discharged. In addition, the switch control circuit419may have a function of turning off all the balancing switches418in response to a balancing OFF command from the control unit3while the vehicle is running. The balancing timer414measures an elapsed time from the start of balancing, controls the balancing switch418when the elapsed time reaches a discharge time included in the discharge instruction from the control unit3, and ends the balancing. Specifically, when the elapsed time reaches the set discharge time, the switch control circuit419performs control to turn off the turned-on switch among the switches BSW1to BSWn in the balancing switch418. As a result, the discharging of the battery cells2that are being discharged is stopped, and the balancing ends. Note that in the balancing timer414, instead of setting the discharge time according to the discharge instruction from the control unit3, the discharge time may be set to a predetermined value set in advance. In addition, when the plurality of battery cells2are being discharged, the same discharging time may be set for all the battery cells2being discharged. Alternatively, the balancing timer414may have n timers, which are the same as the number of battery cells2, so that the discharge time can be set individually for each battery cell2. By doing so, even while the control unit3is stopped, an individual discharge time can be set for each battery cell2, and thus more precise balancing can be performed. Here, the balancing current flowing at the time of balancing is generally larger than a current consumption of the cell con IC410. Therefore, the priority of the current to be stopped when the cell con41fails is higher for the balancing current than for the current consumption of the cell con IC410. In the battery management device1of the present embodiment, since the balancing timer414is arranged in the cell con41, even if the main timer412and the stop management unit413fail at the same time, the balancing current can be stopped by the balancing timer414to reduce the power consumption of the battery cell2. However, in this case, since the operation of the cell con IC410is continuing, the power of the battery cell2is consumed by the current consumption of the cell con IC410though the current consumption is smaller than the balancing current. In the present embodiment, the stop management unit413includes a sub-timer4130. The sub-timer4130is a timer provided separately from the main timer412, and measures the elapsed time after the cell con41starts the balancing like the main timer412. Then, when the measured elapsed time reaches a predetermined stop time, the start and stop circuit411is instructed to stop the cell con41. A stop time in the sub-timer4130is preferably longer than the balancing time, and may be a preset fixed value or a value dynamically set according to the balancing time. As a result, even when the main timer412cannot operate normally due to a failure or the like, the stop management unit413can stop the cell con41to end the balancing and suppress the power consumption of the battery cells2. According to the first embodiment of the present invention described above, the following operational effects are exhibited. (1) The battery management device1includes the cell cons41and42that perform the balancing for adjusting the voltages of the plurality of battery cells2that are secondary batteries, and the control unit3that controls the cell cons41and42. The cell con41includes the main timer412that measures the elapsed time for stopping the cell con41, and the stop management unit413that stops the cell con41when the main timer412is abnormal. In the battery management device1, the first power supply that supplies power to the main timer412and the stop management unit413, that is, the battery cell2, and the second power supply that supplies power to the control unit3, that is, the lead storage battery7are power supplies different from each other. Since this is done, it is possible to improve reliability in balancing while suppressing power consumption during balancing. (2) The control unit3has the normal operation mode in which power is supplied from the lead storage battery7to operate, and the low power consumption mode in which power consumption is lower than that in the normal operation mode. The control unit3performs a balancing instruction for the cell cons41and42during the operation in the normal operation mode, and then shifts to the low power consumption mode. The cell cons41and42perform balancing when the control unit3is operating in the low power consumption mode. Since this is done, the power consumption of the lead storage battery7during balancing can be suppressed. (3) The cell con41has the balancing timer414that ends the balancing when the elapsed time from the start of the balancing reaches a predetermined discharge time. Since this is done, even if the main timer412and the stop management unit413fail at the same time, it is possible to reduce the power consumption of the battery cell2. (4) The stop management unit413has the sub-timer4130that is provided separately from the main timer412and measures the elapsed time. When the elapsed time measured by the main timer412reaches the balancing time set by the control unit3, or when the elapsed time measured by the sub-timer4130reaches a predetermined stop time longer than the balancing time, the cell con41stops. Since this is done, even if the main timer412is abnormal, the power consumption of the battery cell2can be suppressed by stopping the cell con41and ending the balancing. Second Embodiment Next, a second embodiment of the present invention will be described. In the present embodiment, an example will be described in which the stop management units413in the cell cons41and42are realized by means different from that described in the first embodiment. Note that a configuration of a battery management device according to the present embodiment is the same as that of the battery management device1ofFIG.1described in the first embodiment, and thus a description thereof will be omitted. In addition, as in the first embodiment, since the cell cons41and42have the same configuration, only the cell con41will be described below, and the description of the cell con42will be omitted. FIG.3is a diagram illustrating a configuration of a cell con41according to a second embodiment of the present invention. As illustrated inFIG.3, in the cell con41of the present embodiment, the stop management unit413includes a sub-timer4130and a comparison unit4131. In addition, in other respects, the cell con41has the same configuration as that of the first embodiment illustrated inFIG.2. Similarly to the one described in the first embodiment, the sub-timer4130is a timer provided separately from the main timer412, and measures the elapsed time after the cell con41starts balancing, that is, the elapsed time for stopping the cell con41. The comparison unit4131compares the elapsed time measured by the main timer412with the elapsed time measured by the sub-timer4130. As a result, when a difference between these comparison times is a predetermined value or more, it is determined that a time lag has occurred between the main timer412and the sub-timer4130, and the start and stop circuit411is instructed to stop the cell con41. As a result, similarly to the first embodiment, even when the main timer412cannot operate normally due to a failure or the like, the stop management unit413can stop the cell con41to end the balancing and suppress the power consumption of the battery cells2. Further, in this case, the failure of the main timer412may be notified from the cell con41to the control unit3. By doing so, it becomes possible for the control unit3to grasp a location of the failure. According to the second embodiment of the present invention described above, in addition to (1) to (3) described in the first embodiment, the following operational effects are further exhibited. (5) The stop management unit413includes the sub-timer4130provided separately from the main timer412for measuring the elapsed time, and the comparison unit4131that compares the elapsed time measured by the main timer412with the elapsed time measured by the sub-timer4130. When the elapsed time measured by the main timer412reaches the balancing time set by the control unit3, or when the difference between the elapsed times compared by the comparison unit4131is a predetermined value or more, the cell con41stops. Since this is done, even if the main timer412is abnormal, the power consumption of the battery cell2can be suppressed by stopping the cell con41and ending the balancing. Third Embodiment Next, a third embodiment of the present invention will be described. In the present embodiment, an example in which the stop management units413in the cell cons41and42are realized by an analog circuit will be described. Note that a configuration of a battery management device according to the present embodiment is the same as that of the battery management device1ofFIG.1described in the first embodiment, and thus a description thereof will be omitted. In addition, as in the first embodiment, since the cell cons41and42have the same configuration, only the cell con41will be described below, and the description of the cell con42will be omitted. FIG.4is a diagram illustrating a configuration of a cell con41according to a third embodiment of the present invention. As illustrated inFIG.4, in the cell con41according to the present embodiment, the stop management unit413has an RC filter including a resistor RS and a capacitor Cs. In addition, in other respects, the cell con41has the same configuration as the first and second embodiments illustrated inFIGS.2and3, respectively. In the cell con41illustrated inFIG.4, the stop management unit413configured by an RC filter is provided outside the cell con IC410and is connected to the start and stop circuit411in the cell con IC410via a signal input terminal Tws. The stop management unit413may be arranged inside the cell con IC410. In the stop management unit413, every time a communication signal from the control unit3is input to the cell con IC410via a communication terminal Tcom, the capacitor Cs in the RC filter is charged. When the control unit3stops and the communication signal is not input after the balancing instruction, a voltage signal whose voltage monotonically decreases at a rate according to a time constant of the RC filter is applied from the RC filter to the signal input terminal Tws by using the charge charged in the capacitor Cs. That is, in the stop management unit413, the RC filter functions as a voltage signal output circuit that outputs a voltage signal whose voltage monotonously changes according to the elapsed time after the cell con41starts the balancing. Note that the voltage signal output from the stop management unit413may have a voltage that monotonously changes according to the elapsed time from the start of balancing. For example, the stop management unit413may output a voltage signal that monotonically increases according to the elapsed time. The start and stop circuit411monitors the voltage signal input from the stop management unit413via the signal input terminal Tws, and maintains the operation of the cell con IC410when the voltage signal is a predetermined operating voltage V or more, while stops the cell con IC410when the voltage signal is less than the operating voltage V. The operating voltage V is determined according to the time constant of the RC filter included in the stop management unit413and the balancing time set for the main timer412. Specifically, when the time during which the voltage signal of the stop management unit413is held at the operating voltage V or more after the start of balancing is a voltage holding time, the operating voltage V is determined so that the voltage holding time is longer than at least the balancing time. That is, the RC filter of the stop management unit413holds the voltage of the voltage signal output to the start and stop circuit411within the range of the operating voltage V or more during the voltage holding time longer than the balancing time set by the control unit3. As a result, similarly to the first and second embodiments, even when the main timer412cannot operate normally due to a failure or the like, the stop management unit413can stop the cell con41to end the balancing and suppress the power consumption of the battery cells2. According to the third embodiment of the present invention described above, in addition to (1) to (3) described in the first embodiment, the following operational effects are further exhibited. (6) The stop management unit413has the RC filter that functions as the voltage signal output circuit that outputs the voltage signal whose voltage monotonously changes according to the elapsed time. The RC filter holds the voltage of the voltage signal within a predetermined operating voltage range for a predetermined voltage holding time longer than the balancing time set by the control unit3. When the elapsed time measured by the main timer412reaches the balancing time, or when the voltage of the voltage signal output from the RC filter falls outside the operating voltage range, the cell con41stops. Since this is done, even if the main timer412is abnormal, the power consumption of the battery cell2can be suppressed by stopping the cell con41and ending the balancing. Fourth Embodiment Next, a fourth embodiment of the present invention will be described. In the present embodiment, an example will be described in which the stop management units413in the cell cons41and42are realized in association with a specific failure mode of the main timer412. Note that a configuration of a battery management device according to the present embodiment is the same as that of the battery management device1ofFIG.1described in the first embodiment, and thus a description thereof will be omitted. In addition, as in the first embodiment, since the cell cons41and42have the same configuration, only the cell con41will be described below, and the description of the cell con42will be omitted. The purpose of arranging the stop management unit413in the cell con41in the battery management device1is to suppress the power consumption of the battery cells2by stopping the cell con41after the balancing is performed even if the main timer412fails. Therefore, it is not necessary to be able to handle all the failure modes assumed in the main timer412, and the stop management unit413that is capable of handling only the failure mode in which the cell con41cannot be stopped may be used. That is, the stop management unit413does not necessarily have to detect all failures of the main timer412. In the present embodiment, an example of such a stop management unit413will be described. FIG.5is a diagram illustrating a configuration of a cell con41according to a fourth embodiment of the present invention. As illustrated inFIG.5, in the cell con41according to the present embodiment, the main timer412has a timer IC4120and a voltage dividing circuit configured with resistors RP and RM connected to a signal output terminal Set of the cell con IC410. In addition, the stop management unit413has a resistor RS connected between the resistor RP and the resistor RM. Note that in other respects, the cell con41has the same configuration as that of the first to third embodiments illustrated inFIGS.2to4, respectively. In the cell con41illustrated inFIG.5, the main timer412is provided outside the cell con IC410. Note that the main timer412may be arranged inside the cell con IC410. The timer IC4120of the main timer412is connected to the start and stop circuit411in the cell con IC410via the signal input terminal Tws. A capacitor Cs is connected between the signal input terminal Tws and the timer IC4120, and the capacitor Cs is charged every time a communication signal from the control unit3is input to the cell con IC410via the communication terminal Tcom. The timer IC4120has a start signal output terminal WAKE and a set signal input terminal Tset. The start signal output terminal WAKE is connected to the signal input terminal Tws of the cell con IC410, and the set signal input terminal TSet is connected between the resistors RP and RM of the voltage dividing circuit. When the balancing time is set by the control unit3, the cell con IC410outputs a voltage from the signal output terminal Set to the voltage dividing circuit of the main timer412according to a set balancing time. The timer IC4120reads a voltage applied to the set signal input terminal Tset at a predetermined voltage division ratio from the voltage dividing circuit according to the voltage of the signal output terminal Set, and sets a start time of the cell con IC410based on the voltage. At this time, for example, the higher the voltage of the set signal input terminal Tset, the longer the start time is set. Then, during the set start time, the start signal output terminal WAKE outputs a start signal of a predetermined voltage or more to the signal input terminal Tws of the cell con IC410. Note that as the voltage of the start signal output from the timer IC4120, a voltage equal to or higher than the operating voltage V described in the third embodiment is set. When the set start time has elapsed, the timer IC4120stops outputting the start signal and sets the voltage applied to the signal input terminal Tws to less than the operating voltage V. The start and stop circuit411monitors the start signal input from the timer IC4120via the signal input terminal Tws, and maintains the operation of the cell con IC410when the start signal is a predetermined operating voltage V or more, while stops the cell con IC410when the voltage signal is less than the operating voltage V. By such an operation of the start and stop circuit411, the main timer412can stop the cell con41when the start time corresponding to the balancing time has elapsed. Here, as a failure mode that is likely to occur in the main timer412, a failure in which the resistor RP or the resistor RM of the voltage dividing circuit is in an open state can be considered. When the resistor RP is in the open state, the voltage applied to the signal input terminal Tset in the timer IC4120becomes 0 V regardless of the voltage of the signal output terminal Set. Therefore, in this case, since the start time set in the timer IC4120becomes shorter than usual, the power consumption of the battery cell2does not continue without stopping the cell con41after the end of balancing. However, on the other hand, when the resistor RM is in the open state, the voltage applied to the set signal input terminal Tset becomes higher than usual. Therefore, in this case, since the start time set in the timer IC4120becomes longer than usual, the power consumption of the battery cell2continues without stopping the cell con41after the end of balancing. As described above, in the configuration of the main timer412as in the present embodiment, unless any measures are taken, a situation occurs that the power consumption of the battery cell2cannot be suppressed depending on the failure mode of the main timer412. However, in the present embodiment, since the stop management unit413is configured by using the resistor RS connected between the resistor RP and the resistor RM, it is possible to prevent the above situation from occurring. Specifically, even when the resistor RM is in the open state, the set signal input terminal Tset of the timer IC4120is grounded via the resistor RS of the stop management unit413. Therefore, the voltage applied to the set signal input terminal Tset does not become so large as compared with a normal time, and it is possible to set the start time that is allowable in the system and stop the cell con41. That is, the stop management unit413can shorten the start time when the start time becomes abnormally long in the main timer412. As a result, similarly to the first to third embodiments, even when the main timer412cannot operate normally due to a failure or the like, the stop management unit413can stop the cell con41to end the balancing and suppress the power consumption of the battery cells2. According to the fourth embodiment of the present invention described above, in addition to (1) to (3) described in the first embodiment, the following operational effects are further exhibited. (7) The main timer412sets the start time for the cell con41according to the balancing time set by the control unit3. The cell con41stops when the elapsed time from the start of balancing reaches the start time. The stop management unit413shortens the start time when the start time becomes abnormally long in the main timer412. Since this is done, even if the main timer412is abnormal, the power consumption of the battery cell2can be suppressed by stopping the cell con41and ending the balancing. Fifth Embodiment Next, a fifth embodiment of the present invention will be described. In the present embodiment, an example will be described in which a timer for switching the operation mode of the control unit3is further provided. FIG.6is a diagram illustrating a configuration of a battery management device according to a fifth embodiment of the present invention. The battery management device1illustrated inFIG.6further includes a control-side timer8in addition to the components of the first embodiment described inFIG.1. The control-side timer8measures a time after the control unit3stops an operation thereof when performing balancing, and starts the control unit3when the measured time reaches the balancing time to restart the operation thereof. The configurations other than the control-side timer8are the same as those inFIG.1, and the description thereof will be omitted. In addition, the cell cons41and42can have any of the configurations ofFIGS.2to5described in the first to fourth embodiments, respectively. In the present embodiment, the control unit3sets a balancing time for the main timer412when performing balancing, and also sets the balancing time for the control-side timer8, and then enters a stop or standby state and shifts to the low power consumption mode. Note that at this time, the control unit3may further set the discharge time or the stop time to the balancing timer414or the sub-timer4130in the stop management unit413. The control-side timer8measures a time after the control unit3shifts to the low power consumption mode, and restarts the control unit3when the time reaches the set balancing time to shift to the normal mode. Then, the control unit3sets the balancing time for the main timer412and the control-side timer8and then enters the stop or standby state again. Even in this case, the discharge time or the stop time may be set to the balancing timer414or the sub-timer4130in the stop management unit413. In the battery management device1of the present embodiment, such an operation is repeated while the vehicle is stopped. Note that if the time is longer than the balancing time, a time different from the balancing time may be set for the control-side timer8. According to the battery management device1of the present embodiment, by performing the above-mentioned operation using the control-side timer8, the balancing can be performed in several steps while the vehicle is stopped. Generally, since the voltage of the battery cell2immediately after the vehicle is stopped is unstable, there is a problem that error becomes large if the balancing control is performed using the voltage immediately before or after the vehicle is stopped. However, in the battery management device1of the present embodiment, the balancing control can be performed using a stable voltage of the battery cell2when a certain amount of time has passed after the vehicle is stopped. Therefore, it is possible to perform precise balancing. In addition, when individually setting the balancing time for each battery cell2to perform the balancing, it is generally necessary that the balancing timer414has the same number of timers as the number of battery cells2as described above. However, in the battery management device1of the present embodiment, it is not necessary for the balancing timer414to have a plurality of timers by dividing and balancing as described above. That is, the balancing time is set for one battery cell2during one balancing time, and by repeating such a setting for the number of battery cells2, it is possible to discharge all the battery cells2in individual balancing times. As a result, the balancing timer414can be realized with only one timer, and the circuit of the cell con41can be simplified. In particular, when a large number of battery cells2are monitored by the battery management device1, an effect of miniaturization and cost reduction by simplifying the circuit is increased. Note that the control-side timer8may be used to further monitor the main timer412. In this case, by setting a time longer than the balancing time set in the main timer412for the control-side timer8and checking whether or not the main timer412is stopped when the control unit3is restarted, it is possible to diagnose the main timer412. However, in the case in which the vehicle is transported, since the power supply from the lead storage battery7is cut off, the main timer412cannot be diagnosed using the control-side timer8. Therefore, in this case, a function of stopping the cell con41by the stop management unit413is required so that the cell con41can be stopped and the power consumption of the battery cell2can be suppressed even if the main timer412fails. According to the fifth embodiment of the present invention described above, in addition to (1) to (7) described in the first to fourth embodiments, the following operational effects are further exhibited. (8) The battery management device1includes the control-side timer8that measures the time after the control unit3shifts to the low power consumption mode. The control unit3shifts from the low power consumption mode to the normal operation mode based on the time measured by the control-side timer8. Since this is done, it is possible to perform precise balancing while reducing a circuit scale. Note that the embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the characteristics of the invention are impaired. In addition, although various embodiments or modifications have been described above, the present invention is not limited to these contents. Other modes considered within the scope of the technical idea of the present invention are also included in the scope of the present invention. REFERENCE SIGNS LIST 1battery management device2battery cell3control unit5insulating means7lead storage battery8control-side timer41cell controller (cell con)42cell controller (cell con)410cell con IC411start and stop circuit412main timer413stop management unit414balancing timer415power supply circuit416communication circuit417cell interface circuit418balancing switch419switch control circuit | 42,510 |
11862999 | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Referring toFIG.1,FIG.2, andFIG.3,FIG.1is a structural schematic view of the online reconfigurable battery system with SPM according to the present invention;FIG.2is a schematic view of the operation modes of the EBM of the online reconfigurable battery system with SPM according to the present invention;FIG.3is a schematic view of the operation modes of the SPM of the online reconfigurable battery system with SPM according to the present invention. As shown inFIGS.1-3, the online reconfigurable battery system with SPM of the present invention includes: a plurality of battery module strings connected in parallel, each battery module string further comprising: a surge protection module (SPM)101, and a plurality of enable/bypass modules (EBM)102connected in series, the plurality of enable/bypass modules102connected in series are serially connected to the SPM101. Wherein, the EBM102further comprises: a battery, a first switch S1, and a second switch S2; the first switch S1and the battery module are connected in series, and then connected in parallel with the second switch S2to form a battery module with enable or bypass function. Moreover, the SPM102further comprises: a variable resistor Rv, a third switch S3, and a fourth switch S4; the third switch S3and the variable resistor Rv are connected in series, and then connected in parallel with the fourth switch S4to control the buffering of the surge current. As shown inFIG.2, the EBM102has three operation modes: (a) enable mode, (b) bypass mode, and (c) disable mode. Specifically, when the first switch S1is on and the second switch S2is off, the EBM102is in the enable mode, in other words, the battery is ON. When the first switch S1is off and the second switch S2is on, the EMB102is in the bypass mode. In other words, the battery is OFF and is not connected in series to the other battery modules of the battery system, and the current flows through a bypass path201connected in parallel with the battery. When the first switch S1is off and the second switch S2is off, the EBM102is in the disable mode, in other words, the entire EBM102is disconnected from the battery module string. It is worth noting that in the bypass mode, the EBM102is still in series with the other EBMs102in the battery module string to which it belongs. The battery is bypassed. On the other hand, in the disable mode, the EBM does not maintain a serial connection with other EBMs102in the battery module string. As shown inFIG.3, the SPM101also has three operation modes: (a) resistor mode, (b) connect mode, and (c) disconnect mode. Specifically, when the third switch S3is on and the fourth switch S4is off, the SPM101is in the resistor mode, and the current of the SPM101will flow through the variable resistance Rv. When the third switch S3is off and the fourth switch S4is on, the SPM101is in the connect mode, and the current of the SPM101does not flow through the variable resistor Rv, instead, the current flows through the connection path301on the side. When the third switch S3is off and the fourth switch S4is off, the SPM101is in the disconnect mode, and no current flows through the SPM101. It is worth noting that, in a preferred embodiment, when the third switch S3and the fourth switch S4of the SPM101are on at the same time, the SPM101is also in the connect mode. The following describes the operation modes of the SPM101of the present invention in a finite-state machine (FSM) manner.FIG.4is a schematic view of the finite state machine corresponding to the operation modes of the SPM101according to the present invention. As shown inFIG.4, the finite state machine of the SPM includes the following five states: fault-testing state (fault-testing), read new GPIO control signal state (new_GPIO), disconnect mode state (disconnect), connect mode state (connect), and resistor mode and then fade out state (R-mode, Fade-out). When the battery system is powered on, the SPM first enters the fault-testing state; when a system error is detected, the SPM enters the disconnect mode (disconnect) until the SPM receives a reset command from the system, and then returns to the fault-testing state; otherwise, as a system error is not detected, the SPM enters the read the new GPIO control signal state (New_GPIO). In the New_GPIO state, if the setting of the received new GPIO control signal is (H, H) or (L, L), the SPM will enter the disconnect mode state until a reset command is received; otherwise, if the new setting of the GPIO control signal is different from the old setting, it enters the resistor mode and then gradually fades out of the resistor mode (R-mode, Fade-out); on the contrary, if the new setting of the GPIO control signal is the same as the old setting, the SPM enters the connect mode state. In the state after the resistor mode is faded out, the current value is measured, and if the current is higher than a current threshold, the disconnect mode state is entered until a reset command is received; otherwise, the connect mode state is entered. In the connect mode state, if an overcurrent condition is detected, that is, a surge current occurs, the SPM will return to the resistor mode again, and then gradually fade out of the resistor mode; on the other hand, if the SPM receives a new GPIO control signal setting command, the SPM enters the state of reading the new GPIO control signal (new_GPIO), and then operates according to the new setting of the received GPIO control signal. Specifically, the aforementioned new setting command of the GPIO control signal refers to the control setting signal of the third switch S3and the fourth switch S4of the SPM; wherein, (H, H) and (L, L) both represent that the third switch S3and the fourth switch S4are turned off at the same time. It is worth noting that when the value of the GPIO control signal is (H, H) or (L, L), both combinations correspond to the mode in which the third switch S3and the fourth switch S4are turned off at the same time; on the other hand, the switching between (H, L) and (L, H) corresponds to switching from the resistor mode to the connect mode. It is worth noting that the reset command and the new setting command of the GPIO control signal are all issued by the control process of the battery system that can be reconfigured in real time, i.e., online. The time when the reconfigurable battery system capable of real-time reconfiguration issues the reset command and the new setting command of the GPIO control signal can be booting, after repairing and replacing the battery, or detecting the need for reconfiguration. In other words, when the online reconfigurable battery system is turned on, repaired and replaced, or is detected to be reconfigured, a reset command can be issued to trigger the SPM in the disconnect mode to return to the fault-testing state and re-examine the faulty condition of the SPM. On the other hand, the online reconfigurable battery system can also be in the connect mode when the new setting command of the GPIO control signal is issued after the battery is repaired and replaced, or when the reconfiguration is detected. After receiving the new setting command of the GPIO control signal, each SPM enters the disconnect mode, the resistor mode (and then fades out), or stays in the connect mode according to the new setting command of the GPIO control signal. As such, it can be ensured that each SPM of the present invention can be activated when the battery system is turned on, repaired and replaced, or is detected to be reconfigured, and carry out the necessary surge detection to achieve the effect of protecting the battery module string when the surge occurs. It should be further explained that the aforementioned so-called resistor mode and then gradually fade out state means that the resistance value of the variable resistor Rv gradually decreases from a first resistance value to a second resistance value within a preset time, for example, in 50 ms from 20Ω to 0.2Ω. By entering the resistor mode and then gradually fading out (that is, reducing the resistance value), the impact of the surge can be buffered. For example, during the operation, when the battery system needs to be reconfigured at a certain time point T, after issuing a new setting command of the GPIO control signal, each SPM enters the resistor mode and then gradually fades out. When the SPM is gradually reducing the resistance value, for example, after 5 ms, each EBM in each battery module string in the battery system is based on the new settings issued by the battery system. When the resistance value of the variable resistor Rv is reduced to a very small resistance value, it can be determined whether the SPM should enter the connect mode or the disconnect mode according to whether the current exceeds the threshold value. In summary, the SPM of the present invention can be activated when the online reconfigurable battery system is about to be reconfigured, or when an overcurrent condition is detected, and an activation method is performed to ensure that the SPM can buffer the impact of the instantaneous current surge. Specifically, the disconnect mode of the SPM of the present invention can be regarded as adding another layer of protection to the disable mode of each EBM to increase the ability and flexibility of partial operation of the battery system. In other words, by disconnecting individual battery module strings or battery modules in a distributed manner, the present invention can more effectively isolate individual faulty battery module strings or battery modules while still providing partial operation of the battery system. For example, if a battery module fails, the battery module string can be disconnected for isolation for maintenance, while other battery module strings can still be used for partial operations. On the other hand, if the battery module or battery module string needs to be hot-plugged, the battery module string and the battery module are isolated to provide double protection. FIG.5shows the corresponding activation method of the SPM of the present invention. As shown inFIG.5, the activation method includes the following steps:Step S501: Start the battery system and perform initialization;Step S502: Check each SPM; if a fault is detected in the SPM, go to step S503; otherwise, go to step S505;Step S503: Set the old setting (old_GPIO) of the SPM to the third switch and the fourth switch to be off (L, L) at the same time;Step S504: The SPM enters the disconnect mode until a reset command is received; when the reset command is received, return to step S502;Step S505: Read a new setting (new_GPIO) command;Step S506: If the new setting is (H, H) or (L, L), perform step S507;Step S507: Store the new setting (new_GPIO) into the old setting (old_GPIO); then return to step S504;Step S508: If the new setting (new_GPIO) is different from the old setting (old_GPIO), go to step S509; otherwise, go to step S512;Step S509: The new setting (new_GPIO) is stored in the old setting (old_GPIO); the SPM enters the resistor mode, and then gradually fades out of the resistor mode;Step S510: if the current is higher than a threshold value, go to step S511; otherwise, go to step S512;Step S511: Set the old setting (old_GPIO) to (H, H); then return to step S504;Step S512: The SPM enters the connection mode, and then waits until receiving a new setting command (new_GPIO) or detects an overcurrent condition, that is, surge current;Step S513: If the surge current is detected, return to step S509; otherwise, return to step S505. Specifically, the fade-out of the resistor mode in step S509means that the resistance value of the variable resistor Rv gradually decreases from a first resistance value to a second resistance value within a predetermined time. For example, in a preferred embodiment, the predetermined time is in the range of 5 ms-1 s, or preferably, 50 ms; furthermore, the first resistance value and the second resistance value are both greater than the resistance value of the battery module string during normal operation, i.e., connect mode. For example, the first resistance value and the second resistance value are 20Ω and 0.2Ω, respectively. It is worth noting that the aforementioned overcurrent condition means that when the battery module string is in operation, the current exceeds the threshold; as such, the SPM enters the resistor mode, which is equivalent to receiving a reconfiguration signal from the battery system. Specifically, the condition for SPM to enter the connect mode from the resistor mode is: in the resistor mode, when the current value is less than the threshold value (Ithreshold), the threshold value can be calculated by the following method: Ithreshold=Iconnect-max*(Rconnect/RR-mode), where Iconnectis the total resistance value of the battery module string in connect mode, and RR-modeis the resistance value of the variable resistor and Rconnectis the total resistance value of the battery module string in the connect mode, and Iconnect-maxis the maximum allowable current value. The Ithresholdcalculated in this way is the current threshold value for the SPM to enter the connect mode from the resistor mode. The current threshold value can be between 10 A-1000 A, depending on the application. For example, for electric locomotives, the threshold value can be set to 10 A, while for grid-connected ESS container, the value can be set to 1000 A. In a preferred embodiment, the current threshold is 300 A. For example, during the transition period of 50 ms reconfiguration, the fading out of the resistor mode of the SPM will change the resistance value from 20Ω to 0.2Ω, both of which are greater than the normal serial resistance (for example, about 45 mΩ). The current decay ratio in resistor mode is between 0.045/20 and 0.045/0.2. At the end of 50 ms, the SPM will determine to disconnect or resume normal connection by comparing its own current (in resistor mode) with the threshold value (67.5 A=300 A*(0.045/0.2)). In summary, the online reconfigurable battery system with surge protection modules (SPM) of the present invention and the related activation method, by arranging the SPM in series with the battery module string, can be used when the battery system is started or reset, so that the surge is smoothed to prevent the battery module and the battery module string from being impacted and causing short circuit damage. Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. | 15,129 |
11863000 | DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION FIG.1shows a perspective view of a vehicle100according to an example embodiment of the sixth aspect of the invention. The vehicle as shown is a heavy-duty truck comprising an energy storage system1(not shown) according to an example embodiment of the invention, such as the energy storage system shown inFIG.2. Accordingly, the truck100may be a fully electric vehicle, comprising one or more electric motors (not shown) for propelling the truck100. As mentioned in the above, the vehicle100may also for instance be a hybrid vehicle, comprising also e.g. an internal combustion engine (not shown). As also mentioned in the above, the present invention is applicable to many different kinds of vehicles, including but not limited to other types of trucks, buses, construction equipment, such as wheel loaders, excavators etc., passenger cars and also marine vessels. FIG.2shows a schematic view of an energy storage system1according to an example embodiment of the present invention. The energy storage system1comprises one or more battery units11for storing electrical energy. The one or more battery units11may be any kind/s of battery unit/s, and may for example comprise one or more battery cells11′ connected electrically in series. The battery cells11′ may for example be lithium ion battery cells, but may of course be of any other kind known to the skilled person, as long as they are capable of storing electrical energy. The energy storage system1further comprises at least one high voltage switch12′,12″,12″ for connection and disconnection of the one or more battery units11to at least one load20, such as an electrical machine. In the shown embodiment there are three high voltage switches, i.e.12′,12″ and12′″. The switches12′,12″,12″ may be of any kind known to the skilled person, such as an electromechanical switch. In addition, in the shown embodiment there are two loads20connected electrically to the battery unit11. The loads20may as mentioned be electric motors for propulsion of the vehicle100as shown in e.g.FIG.1. The one or more loads20may of course be any other kind of load which consumes electrical power, such as a fan, an air conditioning system etc. In case the load20is not configured to be connected directly to a high voltage system, it may be connected thereto via a transformer (not shown) which reduces the voltage level to a suitable level. In the shown embodiment, the high voltage switch12″ is part of a pre-charge circuit16of the battery unit11, being represented by a box with dashed lines. The pre-charge circuit16may be used to pre-charge the energy storage system1at start up, such as when starting up the energy storage system1in the vehicle100. The pre-charge circuit16comprises at least one resistor R connected in series with the high voltage switch12″. During pre-charge, the high voltage switch12′″ is closed, i.e. it provides an electrical connection, while the high voltage switch12″ is open, i.e. disconnected. The high voltage switch12′ is also closed. Thereby the system1is in a connected and powered state. The high voltage switch12″ may be closed after a predetermined time period, and/or when a certain condition has been fulfilled, indicative of that the energy storage system1is ready to be used for powering the load(s)20with sufficient power to drive the load(s)20. The energy storage system1further comprises a fuse13for disconnection of the one or more battery units11when the energy storage system1experiences an overcurrent being above a predetermined overcurrent value. The fuse13is here a pyrotechnic fuse, even though any other type may be used, as mentioned in the above. The fuse13is here provided between the battery cell(s)11′ and the high voltage switches12″ and12′″. It shall be noted that the energy storage system1may in an alternative embodiment comprise more than one fuse, which are e.g. electrically connected in series and/or in parallel. The energy storage system1is configured to:during use, identify if a condition has occurred which requires immediate shutdown of the energy storage system1; and if it is identified that immediate shutdown is required, the energy storage system1is further configured to:measure a value indicative of current in the energy storage system1;if the measured value indicative of current is equal to or below a level at which it is safe to open the at least one high voltage switch12′,12″,12′″, the energy storage system1is configured to immediately shut down the energy storage system1by opening the at least one high voltage switch12′,12″,12′″, andif the measured value indicative of current is above the level at which it is safe to open the at least one high voltage switch12′,12″,12′″, but lower than the predetermined overcurrent value, the energy storage system1is configured to immediately shut down the energy storage system1by actively triggering the fuse13. In the shown example, current is measured by use of a current sensor17which is provided proximate the battery cell(s)11′. Of course, current in the system1may be measured in any other way known to the skilled person. Further, in the shown example, in order to shut down the energy storage system1by one or more of the high voltage switches12′,12″,12′″, only the switch12′ may be opened, and/or the switches12″ and12′″ may both be opened. According to an embodiment, the fuse13may be actively triggered when the following condition is fulfilled: IFuse>Iactual<IBreak connector wherein IBreak connectoris a maximum level at which it is safe to open the at least one high voltage switch12′,12″,12′″, IActualis the current measured by e.g. the current sensor17, and IFuseis the predetermined overcurrent value. This range may in one embodiment be defined as a “limbo range” in which the fuse13will not be automatically triggered and where also the at least one high voltage switch12′,12″,12′″ may be damaged, or not possible to open due to a too high current. However, when the current IActualis lower than IBreak connector, the at least one switch12′,12″,12′″ can be used, implying no need to actively trigger the fuse13. Thereby, the energy storage system1can still in such a situation be shut down without consuming the fuse13. Furthermore, at least one of the level at which it is safe to open the at least one high voltage switch12′,12″,12′″ and the predetermined overcurrent value may be adjustable. Accordingly, the above-mentioned range may be adjustable, implying an increased flexibility. For example, the battery unit11may be reused in another system, such as moved from the truck100inFIG.1to another application. In the other application, other limit values for the above-mentioned range may be required, and by having adjustable levels, a more flexible energy storage system1is achieved. The energy storage system1may further be configured to automatically adjust the at least one of the level at which it is safe to open the at least one high voltage switch12′,12″,12′″ and the predetermined overcurrent value in dependence on a changed vehicle state, such as when changing from a charging state to a driving state, or vice versa. The energy storage system may further be configured to identify if the at least one high voltage switch12′,12″,12′″ is unable to be disconnected, and if the at least one high voltage switch12′,12″,12′″ is unable to be disconnected, the energy storage system1may further be configured to actively trigger the fuse13when it also has been identified that immediate shutdown is required. The condition which requires immediate shutdown may correspond to at least one of the following conditions: an accident of the vehicle100, an emergency stop signal, such as a signal generated when pressing an emergency button, and a short circuit fault. The energy storage system1may as shown further comprise a dedicated hardware device14, wherein the dedicated hardware device14is configured to obtain the measured value indicative of current in the energy storage system1, in this case a value from the current sensor17, and further configured to open the at least one high voltage switch12′,12″,12′″ or actively trigger the fuse13in dependence on the measured value indicative of current in the energy storage system1. The communication channel between the current sensor17and the dedicated hardware14is here indicated by an arrow with a dashed line. The communication may be performed in any suitable manner, such as by a wired and/or wireless connection. The energy storage system1may further comprise a second hardware device15, preferably separate from the dedicated hardware device14, which is configured to monitor if the condition has occurred which requires immediate shutdown of the energy storage system1, and wherein the second hardware device15is further configured to issue a signal to the dedicated hardware device14when the condition has occurred. The signal communicated to the dedicated hardware device14is represented by the arrow with the dashed line provided therebetween. Further, the second hardware device may obtain signals indicative of that the condition has occurred which requires immediate shut down. This is indicated by another arrow with a dashed line inFIG.2. Such signal may for example be a signal indicating that an airbag has been triggered, an accident has occurred or any other signal. As mentioned in the above, the hardware devices14,15are preferably electronic control units. The electronic control units14,15may comprise hardware, and/or hardware and software. As such, the electronic control units may comprise a computer program as disclosed herein. With respect toFIG.3, a flowchart of an embodiment of a method according to the second aspect of the invention is shown. The method may for example be used for the energy storage system1as shown inFIG.2. The method comprises:S1: during use of the energy storage system, identifying if a condition has occurred which requires immediate shutdown of the energy storage system1;S2: measuring a value indicative of current in the energy storage system1when it is identified that immediate shutdown is required;S3: immediately shutting down the energy storage system1by opening the at least one high voltage switch12′,12″,12′″ if the measured value indicative of current is equal to or below a level at which it is safe to open the at least one high voltage switch12′,12″,12′″; andS4: immediately shutting down the energy storage system1by actively triggering the fuse13if the measured value indicative of current is above the level at which it is safe to open the at least one high voltage switch12but lower than the predetermined overcurrent value. The method may comprise further steps as e.g. mentioned in the above. Further, the steps S1-S4 may not necessarily be performed in the above mentioned order, but may be performed in any other order recognized by the skilled person. It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims. | 11,229 |
11863001 | In accordance with common practice, the various features illustrated in the drawings may not be drawn to scale. Accordingly, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. In addition, some of the drawings may not depict all of the components of a given system, method or device. Finally, like reference numerals may be used to denote like features throughout the specification and figures. DESCRIPTION OF EMBODIMENTS Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. FIG.1Ais a block diagram of an RF wireless power transmission system in accordance with some embodiments. In some embodiments, the RF wireless power transmission system150includes a RF charging pad100(also referred to herein as a near-field (NF) charging pad100or RF charging pad100). In some embodiments, the RF charging pad100includes an RF power transmitter integrated circuit160(described in more detail below). In some embodiments, the RF charging pad100includes one or more communications components204(e.g., wireless communication components, such as WI-FI or BLUETOOTH radios), discussed in more detail below with reference toFIG.2A. In some embodiments, the RF charging pad100also connects to one or more power amplifier units108-1, . . .108-nto control operation of the one or more power amplifier units when they drive an external TX antenna array210. In some embodiments, RF power is controlled and modulated at the RF charging pad100via switch circuitry as to enable the RF wireless power transmission system to send RF power to one or more wireless receiving devices via the TX antenna array210. Example power amplifier units are discussed in further detail below with reference toFIG.3A. In some embodiments, the communication component(s)204enable communication between the RF charging pad100and one or more communication networks. In some embodiments, the communication component(s)204are capable of data communications using any of a variety of custom or standard wireless protocols (e.g., IEEE 802.15.4, Wi-Fi, ZigBee, 6LoWPAN, Thread, Z-Wave, Bluetooth Smart, ISA100.11a, WirelessHART, MiWi, etc.) custom or standard wired protocols (e.g., Ethernet, HomePlug, etc.), and/or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. FIG.1Bis a block diagram of the RF power transmitter integrated circuit160(the “integrated circuit”) in accordance with some embodiments. In some embodiments, the integrated circuit160includes a CPU subsystem170, an external device control interface, an RF subsection for DC to RF power conversion, and analog and digital control interfaces interconnected via an interconnection component, such as a bus or interconnection fabric block171. In some embodiments, the CPU subsystem170includes a microprocessor unit (CPU)202with related Read-Only-Memory (ROM)172for device program booting via a digital control interface, e.g. an I2C port, to an external FLASH containing the CPU executable code to be loaded into the CPU Subsystem Random Access Memory (RAM)174(e.g., memory206,FIG.2A) or executed directly from FLASH. In some embodiments, the CPU subsystem170also includes an encryption module or block176to authenticate and secure communication exchanges with external devices, such as wireless power receivers that attempt to receive wirelessly delivered power from the RF charging pad100. In some embodiments, executable instructions running on the CPU (such as those shown in the memory206inFIG.2Aand described below) are used to manage operation of the RF charging pad100and to control external devices through a control interface, e.g., SPI control interface175, and the other analog and digital interfaces included in the RF power transmitter integrated circuit160. In some embodiments, the CPU subsystem also manages operation of the RF subsection of the RF power transmitter integrated circuit160, which includes an RF local oscillator (LO)177and an RF transmitter (TX)178. In some embodiments, the RF LO177is adjusted based on instructions from the CPU subsystem170and is thereby set to different desired frequencies of operation, while the RF TX converts, amplifies, modulates the RF output as desired to generate a viable RF power level. In some embodiments, the RF power transmitter integrated circuit160provides the viable RF power level (e.g., via the RF TX178) to an optional beamforming integrated circuit (IC)109, which then provides phase-shifted signals to one or more power amplifiers108. In some embodiments, the beamforming IC109is used to ensure that power transmission signals sent using two or more antennas210(e.g., each antenna210may be associated with a different antenna zones290or may each belong to a single antenna zone290) to a particular wireless power receiver are transmitted with appropriate characteristics (e.g., phases) to ensure that power transmitted to the particular wireless power receiver is maximized (e.g., the power transmission signals arrive in phase at the particular wireless power receiver). In some embodiments, the beamforming IC109forms part of the RF power transmitter IC160. In some embodiments, the RF power transmitter integrated circuit160provides the viable RF power level (e.g., via the RF TX178) directly to the one or more power amplifiers108and does not use the beamforming IC109(or bypasses the beamforming IC if phase-shifting is not required, such as when only a single antenna210is used to transmit power transmission signals to a wireless power receiver). In some embodiments, the one or more power amplifiers108then provide RF signals to the antenna zones290for transmission to wireless power receivers that are authorized to receive wirelessly delivered power from the RF charging pad100. In some embodiments, each antenna zone290is coupled with a respective PA108(e.g., antenna zone290-1is coupled with PA108-1and antenna zone290-N is coupled with PA108-N). In some embodiments, multiple antenna zones are each coupled with a same set of PAs108(e.g., all PAs108are coupled with each antenna zone290). Various arrangements and couplings of PAs108to antenna zones290allow the RF charging pad100to sequentially or selectively activate different antenna zones in order to determine the most efficient antenna zone290to use for transmitting wireless power to a wireless power receiver (as explained in more detail below in reference toFIGS.9A-9B,10, and11A-11E). In some embodiments, the one or more power amplifiers108are also in communication with the CPU subsystem170to allow the CPU202to measure output power provided by the PAs108to the antenna zones of the RF charging pad100. FIG.1Balso shows that, in some embodiments, the antenna zones290of the RF charging pad100may include one or more antennas210A-N. In some embodiments, each antenna zones of the plurality of antenna zones includes one or more antennas210(e.g., antenna zone290-1includes one antenna210-A and antenna zones290-N includes multiple antennas210). In some embodiments, a number of antennas included in each of the antenna zones is dynamically defined based on various parameters, such as a location of a wireless power receiver on the RF charging pad100. In some embodiments, the antenna zones may include one or more of the meandering line antennas described in more detail below. In some embodiments, each antenna zone290may include antennas of different types (e.g., a meandering line antenna and a loop antenna), while in other embodiments each antenna zone290may include a single antenna of a same type (e.g., all antenna zones290include one meandering line antenna), while in still other embodiments, the antennas zones may include some antenna zones that include a single antenna of a same type and some antenna zones that include antennas of different types. Antenna zones are also described in further detail below. In some embodiments, the RF charging pad100may also include a temperature monitoring circuit that is in communication with the CPU subsystem170to ensure that the RF charging pad100remains within an acceptable temperature range. For example, if a determination is made that the RF charging pad100has reached a threshold temperature, then operation of the RF charging pad100may be temporarily suspended until the RF charging pad100falls below the threshold temperature. By including the components shown for RF power transmitter circuit160(FIG.1B) on a single chip, such integrated circuits are able to manage operations at the integrated circuits more efficiently and quickly (and with lower latency), thereby helping to improve user satisfaction with the charging pads that are managed by these integrated circuits. For example, the RF power transmitter circuit160is cheaper to construct, has a smaller physical footprint, and is simpler to install. Furthermore, and as explained in more detail below in reference toFIG.2A, the RF power transmitter circuit160may also include a secure element module234(e.g., included in the encryption block176shown inFIG.1B) that is used in conjunction with a secure element module282(FIG.2B) or a receiver104to ensure that only authorized receivers are able to receive wirelessly delivered power from the RF charging pad100(FIG.1B). FIG.1Cis a block diagram of a charging pad294in accordance with some embodiments. The charging pad294is an example of the charging pad100(FIG.1A), however, one or more components included in the charging pad100are not included in the charging pad294for ease of discussion and illustration. The charging pad294includes an RF power transmitter integrated circuit160, one or more power amplifiers108, and a transmitter antenna array290having multiple antenna zones. Each of these components is described in detail above with reference toFIGS.1A and1B. Additionally, the charging pad294includes a switch295, positioned between the power amplifiers108and the antenna array290, having a plurality of switches297-A,297-B, . . .297-N. The switch295is configured to switchably connect one or more power amplifiers108with one or more antenna zones of the antenna array290in response to control signals provided by the RF power transmitter integrated circuit160. To accomplish the above, each switch297is coupled with (e.g., provides a signal pathway to) a different antenna zone of the antenna array290. For example, switch297-A may be coupled with a first antenna zone290-1(FIG.1B) of the antenna array290, switch297-B may be coupled with a second antenna zone290-2of the antenna array290, and so on. Each of the plurality of switches297-A,297-B, . . .297-N, once closed, creates a unique pathway between a respective power amplifier108(or multiple power amplifiers108) and a respective antenna zone of the antenna array290. Each unique pathway through the switch295is used to selectively provide RF signals to specific antenna zones of the antenna array290. It is noted that two or more of the plurality of switches297-A,297-B, . . .297-N may be closed at the same time, thereby creating multiple unique pathways to the antenna array290that may be used simultaneously. In some embodiments, the RF power transmitter integrated circuit160is coupled to the switch295and is configured to control operation of the plurality of switches297-A,297-B, . . .297-N (illustrated as a “control out” signal inFIGS.1A and1C). For example, the RF power transmitter integrated circuit160may close a first switch297-A while keeping the other switches open. In another example, the RF power transmitter integrated circuit160may close a first switch297-A and a second switch297-B, and keep the other switches open (various other combinations and configuration are possible). Moreover, the RF power transmitter integrated circuit160is coupled to the one or more power amplifiers108and is configured to generate a suitable RF signal (e.g., the “RF Out” signal) and provide the RF signal to the one or more power amplifiers108. The one or more power amplifiers108, in turn, are configured to provide the RF signal to one or more antenna zones of the antenna array290via the switch295, depending on which switches297in the switch295are closed by the RF power transmitter integrated circuit160. To further illustrate, as described in some embodiments below, the charging pad is configured to transmit test power transmission signals and/or regular power transmission signals using different antenna zones, e.g., depending on a location of a receiver on the charging pad. Accordingly, when a particular antenna zone is selected for transmitting test signals or regular power signals, a control signal is sent to the switch295from the RF power transmitter integrated circuit160to cause at least one switch297to close. In doing so, an RF signal from at least one power amplifier108can be provided to the particular antenna zone using a unique pathway created by the now-closed at least one switch297. In some embodiments, the switch295may be part of (e.g., internal to) the antenna array290. Alternatively, in some embodiments, the switch295is separate from the antenna array290(e.g., the switch295may be a distinct component, or may be part of another component, such as the power amplifier(s)108). It is noted that any switch design capable of accomplishing the above may be used, and the design of the switch295illustrated inFIG.1Cis merely one example. FIG.2Ais a block diagram illustrating certain components of an RF charging pad100in accordance with some embodiments. In some embodiments, the RF charging pad100includes an RF power transmitter IC160(and the components included therein, such as those described above in reference toFIGS.1A-1B), memory206(which may be included as part of the RF power transmitter IC160, such as nonvolatile memory206that is part of the CPU subsystem170), and one or more communication buses208for interconnecting these components (sometimes called a chipset). In some embodiments, the RF charging pad100includes one or more sensor(s)212(discussed below). In some embodiments, the RF charging pad100includes one or more output devices such as one or more indicator lights, a sound card, a speaker, a small display for displaying textual information and error codes, etc. In some embodiments, the RF charging pad100includes a location detection device, such as a GPS (global positioning satellite) or other geo-location receiver, for determining the location of the RF charging pad100. In some embodiments, the one or more sensor(s)212include one or more thermal radiation sensors, ambient temperature sensors, humidity sensors, IR sensors, occupancy sensors (e.g., RFID sensors), ambient light sensors, motion detectors, accelerometers, and/or gyroscopes. The memory206includes high-speed random access memory, such as DRAM, SRAM, DDR SRAM, or other random access solid state memory devices; and, optionally, includes non-volatile memory, such as one or more magnetic disk storage devices, one or more optical disk storage devices, one or more flash memory devices, or one or more other non-volatile solid state storage devices. The memory206, or alternatively the nonvolatile memory within memory206, includes a non-transitory computer-readable storage medium. In some embodiments, the memory206, or the non-transitory computer-readable storage medium of the memory206, stores the following programs, modules, and data structures, or a subset or superset thereof:Operating logic216including procedures for handling various basic system services and for performing hardware dependent tasks;Communication module218for coupling to and/or communicating with remote devices (e.g., remote sensors, transmitters, receivers, servers, mapping memories, etc.) in conjunction with wireless communication component(s)204;Sensor module220for obtaining and processing sensor data (e.g., in conjunction with sensor(s)212) to, for example, determine the presence, velocity, and/or positioning of object in the vicinity of the RF charging pad100;Power-wave generating module222for generating and transmitting power transmission signals (e.g., in conjunction with antenna zones290and the antennas210respectively included therein), including but not limited to, forming pocket(s) of energy at given locations. Power-wave generating module222may also be used to modify transmission characteristics used to transmit power transmission signals by individual antenna zones; andDatabase224, including but not limited to:Sensor information226for storing and managing data received, detected, and/or transmitted by one or more sensors (e.g., sensors212and/or one or more remote sensors);Device settings228for storing operational settings for the RF charging pad100and/or one or more remote devices;Communication protocol information230for storing and managing protocol information for one or more protocols (e.g., custom or standard wireless protocols, such as ZigBee, Z-Wave, etc., and/or custom or standard wired protocols, such as Ethernet); andMapping data232for storing and managing mapping data (e.g., mapping one or more transmission fields);a secure element module234for determining whether a wireless power receiver is authorized to receive wirelessly delivered power from the RF charging pad100; andan antenna zone selecting and tuning module237for coordinating a process of transmitting test power transmission signals with various antenna zones to determine which antenna zone or zones should be used to wirelessly deliver power to various wireless power receivers (as is explained in more detail below in reference toFIGS.9A-9B,100, and11A-11E). Each of the above-identified elements (e.g., modules stored in memory206of the RF charging pad100) is optionally stored in one or more of the previously mentioned memory devices, and corresponds to a set of instructions for performing the function(s) described above. The above identified modules or programs (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are optionally combined or otherwise rearranged in various embodiments. In some embodiments, the memory206, optionally, stores a subset of the modules and data structures identified above. FIG.2Bis a block diagram illustrating a representative receiver device104(also sometimes called a receiver, power receiver, or wireless power receiver) in accordance with some embodiments. In some embodiments, the receiver device104includes one or more processing units (e.g., CPUs, ASICs, FPGAs, microprocessors, and the like)252, one or more communication components254, memory256, antenna(s)260, power harvesting circuitry259, and one or more communication buses258for interconnecting these components (sometimes called a chipset). In some embodiments, the receiver device104includes one or more sensor(s)262such as the one or sensors212described above with reference toFIG.2A. In some embodiments, the receiver device104includes an energy storage device261for storing energy harvested via the power harvesting circuitry259. In various embodiments, the energy storage device261includes one or more batteries, one or more capacitors, one or more inductors, and the like. In some embodiments, the power harvesting circuitry259includes one or more rectifying circuits and/or one or more power converters. In some embodiments, the power harvesting circuitry259includes one or more components (e.g., a power converter) configured to convert energy from power waves and/or energy pockets to electrical energy (e.g., electricity). In some embodiments, the power harvesting circuitry259is further configured to supply power to a coupled electronic device, such as a laptop or phone. In some embodiments, supplying power to a coupled electronic device include translating electrical energy from an AC form to a DC form (e.g., usable by the electronic device). In some embodiments, the antenna(s)260include one or more of the meandering line antennas that are described in further detail below. In some embodiments, the receiver device104includes one or more output devices such as one or more indicator lights, a sound card, a speaker, a small display for displaying textual information and error codes, etc. In some embodiments, the receiver device104includes a location detection device, such as a GPS (global positioning satellite) or other geo-location receiver, for determining the location of the receiver device103. In various embodiments, the one or more sensor(s)262include one or more thermal radiation sensors, ambient temperature sensors, humidity sensors, IR sensors, occupancy sensors (e.g., RFID sensors), ambient light sensors, motion detectors, accelerometers, and/or gyroscopes. The communication component(s)254enable communication between the receiver104and one or more communication networks. In some embodiments, the communication component(s)254are capable of data communications using any of a variety of custom or standard wireless protocols (e.g., IEEE 802.15.4, Wi-Fi, ZigBee, 6LoWPAN, Thread, Z-Wave, Bluetooth Smart, ISA100.11a, WirelessHART, MiWi, etc.) custom or standard wired protocols (e.g., Ethernet, HomePlug, etc.), and/or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. The communication component(s)254include, for example, hardware capable of data communications using any of a variety of custom or standard wireless protocols (e.g., IEEE 802.15.4, Wi-Fi, ZigBee, 6LoWPAN, Thread, Z-Wave, Bluetooth Smart, ISA100.11a, WirelessHART, MiWi, etc.) and/or any of a variety of custom or standard wired protocols (e.g., Ethernet, HomePlug, etc.), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. The memory256includes high-speed random access memory, such as DRAM, SRAM, DDR SRAM, or other random access solid state memory devices; and, optionally, includes non-volatile memory, such as one or more magnetic disk storage devices, one or more optical disk storage devices, one or more flash memory devices, or one or more other non-volatile solid state storage devices. The memory256, or alternatively the nonvolatile memory within memory256, includes a non-transitory computer-readable storage medium. In some embodiments, the memory256, or the non-transitory computer-readable storage medium of the memory256, stores the following programs, modules, and data structures, or a subset or superset thereof:Operating logic266including procedures for handling various basic system services and for performing hardware dependent tasks;Communication module268for coupling to and/or communicating with remote devices (e.g., remote sensors, transmitters, receivers, servers, mapping memories, etc.) in conjunction with communication component(s)254;Sensor module270for obtaining and processing sensor data (e.g., in conjunction with sensor(s)262) to, for example, determine the presence, velocity, and/or positioning of the receiver103, a RF charging pad100, or an object in the vicinity of the receiver103;Wireless power-receiving module272for receiving (e.g., in conjunction with antenna(s)260and/or power harvesting circuitry259) energy from power waves and/or energy pockets; optionally converting (e.g., in conjunction with power harvesting circuitry259) the energy (e.g., to direct current); transferring the energy to a coupled electronic device; and optionally storing the energy (e.g., in conjunction with energy storage device261); andDatabase274, including but not limited to:Sensor information276for storing and managing data received, detected, and/or transmitted by one or more sensors (e.g., sensors262and/or one or more remote sensors);Device settings278for storing operational settings for the receiver103, a coupled electronic device, and/or one or more remote devices; andCommunication protocol information280for storing and managing protocol information for one or more protocols (e.g., custom or standard wireless protocols, such as ZigBee, Z-Wave, etc., and/or custom or standard wired protocols, such as Ethernet); anda secure element module282for providing identification information to the RF charging pad100(e.g., the RF charging pad100uses the identification information to determine if the wireless power receiver104is authorized to receive wirelessly delivered power). Each of the above-identified elements (e.g., modules stored in memory256of the receiver104) is optionally stored in one or more of the previously mentioned memory devices, and corresponds to a set of instructions for performing the function(s) described above. The above identified modules or programs (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are optionally combined or otherwise rearranged in various embodiments. In some embodiments, the memory256, optionally, stores a subset of the modules and data structures identified above. Furthermore, the memory256, optionally, stores additional modules and data structures not described above, such as an identifying module for identifying a device type of a connected device (e.g., a device type for an electronic device that is coupled with the receiver104). Turning now toFIGS.3A through8, embodiments of the RF charging pad100are shown that include a component for modifying impedance values (e.g., a load pick) at various antennas of the RF charging pad100, and descriptions of antennas that include a conductive line forming a meandering line pattern are also provided in reference to these figures. As shown inFIG.3A, some embodiments include an RF charging pad100that includes a load pick106to allow for modifying impedance values at various antennas of the RF charging pad100. In some embodiments, the RF charging pad100includes one or more antenna elements that are each powered/fed by a respective power amplifier switch circuit103at a first end and a respective adaptive load terminal102at a second end (additional details and descriptions of the one or more antenna elements are provided below in reference toFIGS.3B-3C). In some embodiments, the RF charging pad100also includes (or is in communication with) a central processing unit110(also referred to here as processor110). In some embodiments, the processor110is a component of a single integrated circuit that is responsible for managing operations of the RF charging pad100, such as the CPU202illustrated inFIG.1Band included as a component of the RF power transmitter integrated circuit160. In some embodiments, the processor110is configured to control RF signal frequencies and to control impedance values at each of the adaptive load terminals102(e.g., by communicating with the load pick or adaptive load106, which may be an application-specific integrated circuit (ASIC), or a variable resister, to generate various impedance values). In some embodiments, the load pick106is an electromechanical switch that is placed in either an open or shorted state. In some embodiments, an electronic device (e.g., a device that includes a receiver104as an internally or externally connected component, such as a remote that is placed on top of a charging pad100that may be integrated within a housing of a streaming media device or a projector) and uses energy transferred from one or more RF antenna elements of the charging pad100to the receiver104to charge a battery and/or to directly power the electronic device. In some embodiments, the RF charging pad100is configured with more than one input terminal for receiving power (from power amplifier (PA)108,FIG.3A) and more than one output or adaptive load terminal102. In some embodiments, the adaptive load terminals102at a particular zone of the RF charging pad100(e.g., a zone that includes antenna elements located underneath a position at which an electronic device (with an internally or externally connected RF receiver104) to be charged is placed on the charging pad) are optimized in order to maximize power received by the receiver104. For example, the CPU110upon receiving an indication that an electronic device with an internally or externally connected RF receiver104has been placed on the pad100in a particular zone105(the zone105includes a set of antenna elements) may adapt the set of antenna elements to maximize power transferred to the RF receiver104. Adapting the set of antenna elements may include the CPU110commanding load pick106to try various impedance values for adaptive load terminals102that are associated with the set of antenna elements. For example, the impedance value for a particular conductive line at an antenna element is given by the complex value of Z=A+jB (where A is the real part of the impedance value and B is the imaginary part, e.g., 0+j0, 1000+j0, 0+50j, or 25+j75, etc.), and the load pick adjusts the impedance value to maximize the amount of energy transferred from the set of antenna elements to the RF receiver104. In some embodiments, adapting the set of antenna elements also or alternatively includes the CPU110causing the set of antenna elements to transmit RF signals at various frequencies until a frequency is found at which a maximum amount of energy is transferred to the RF receiver104. In some embodiments, adjusting the impedance value and/or the frequencies at which the set of antenna elements transmits causes changes to the amount of energy transferred to the RF receiver104. In this way, the amount of energy transferred to the RF receiver104is maximized (e.g., to transfer at least 75% of the energy transmitted by antenna elements of the pad100to the receiver104, and in some embodiments, adjusting the impedance value and/frequencies may allow up to 98% of the energy transmitted to be received by the receiver104) may be received at any particular point on the pad100at which the RF receiver104might be placed. In some embodiments, the input circuit that includes the power amplifier108can additionally include a device that can change frequencies of the input signal, or a device that can operate at multiple frequencies at the same time, such as an oscillator or a frequency modulator. In some embodiments, the CPU110determines that a maximum amount of energy is being transferred to the RF receiver104when the amount of energy transferred to the RF receiver104crosses a predetermined threshold (e.g., 75% or more of transmitted energy is received, such as up to 98%) or by testing transmissions with a number of impedance and/or frequency values and then selecting the combination of impedance and frequency that results in maximum energy being transferred to the RF receiver104(as described in reference to the adaptation scheme below). In some embodiments, an adaptation scheme is employed to adaptively adjust the impedance values and/or frequencies of the RF signal(s) emitted from the RF antenna(s)120of the charging pad100, in order to determine which combinations of frequency and impedance result in maximum energy transfer to the RF receiver104. For example, the processor110that is connected to the charging pad100tries different frequencies (i.e., in the allowed operating frequency range or ranges) at a given location of the RF charging pad100(e.g., a zone or area of the RF charging pad100that includes one or more RF antenna elements for transmitting RF signals, such as zone105ofFIG.3A) to attempt to adaptively optimize for better performance. For example, a simple optimization either opens/disconnects or closes/shorts each load terminal to ground (in embodiments in which a relay is used to switch between these states), and may also cause RF antennas within the zone to transmit at various frequencies. In some embodiments, for each combination of relay state (open or shorted) and frequency, the energy transferred to the receiver104is monitored and compared to energy transferred when using other combinations. The combination that results in maximum energy transfer to the receiver104is selected and used to continue to transmitting the one or more RF signals to the receiver104. In some embodiments, the adaptation scheme described above is performed as a part of the methods described below in reference toFIGS.9A-9B,10, and11A-11Eto help maximize an amount of energy transferred by the RF charging pad100to the receiver104. As another example, if five frequencies in the ISM band are utilized by the pad100for transmitting radio frequency waves and the load pick106is an electromechanical relay for switching between open and shorted states, then employing the adaptation scheme would involve trying10combinations of frequencies and impedance values for each antenna element120or for a zone of antenna elements120and selecting the combination that results in best performance (i.e., results in most power received at receiver104, or most power transferred from the pad100to the RF receiver104). The industrial, scientific, and medical radio bands (ISM bands) refers to a group of radio bands or parts of the radio spectrum that are internationally reserved for the use of radio frequency (RF) energy intended for scientific, medical and industrial requirements rather than for communications. In some embodiments, all ISM bands (e.g., 40 MHz, 900 MHz, 2.4 GHz, 5.8 GHz, 24 GHz, 60 GHz, 122 GHz, and 245 GHz) may be employed as part of the adaptation scheme. As one specific example, if the charging pad100is operating in the 5.8 GHz band, then employing the adaptation scheme would include transmitting RF signals and then adjusting the frequency at predetermined increments (e.g., 50 MHz increments, so frequencies of 5.75 GHz, 5.755 GHz, 5.76 GHz, and so on). In some embodiments, the predetermined increments may be 5, 10 15, 20, 50 MHz increments, or any other suitable increment. In some embodiments, the antenna elements120of the pad100may be configured to operate in two distinct frequency bands, e.g., a first frequency band with a center frequency of 915 MHz and a second frequency band with a center frequency of 5.8 GHz. In these embodiments, employing the adaptation scheme may include transmitting RF signals and then adjusting the frequency at first predetermined increments until a first threshold value is reached for the first frequency band and then adjusting the frequency at second predetermined increments (which may or may not be the same as the first predetermined increments) until a second threshold value is reached for the second frequency band. For example, the antenna elements120may be configured to transmit at 902 MHz, 915 MHz, 928 MHZ (in the first frequency band) and then at 5.795 GHz, 5.8 GHz, and 5.805 GHz (in the second frequency band). Additional details regarding antenna elements that are capable of operating at multiple frequencies are provided below in reference toFIGS.14A-14D and15. Turning now toFIGS.3B-3C, high-level block diagrams showing a portion of an RF charging pad are illustrated, in accordance with some embodiments. FIG.3Bshows a schematic of a single TX antenna120(which may be a part of an antenna zone that includes one or an array of such antennas120, all forming the charging pad100that is shown inFIG.3A). In some embodiments, the TX antenna120is also referred to as a TX antenna element120. In some circumstances, an RF receiving unit/antenna (RX) (or a device that includes the receiving unit104as an internally or externally connected component) is placed on top of a portion of the pad100that includes the TX antenna120(which includes a conductive line that forms a meandered line arrangement, as shown inFIG.3B). In some embodiments, the receiver104has no direct contact to a metallic conductive line of the single TX antenna120and is just coupled (i.e. in near-field zone) to the TX antenna120. In some embodiments, the TX antenna120has two or more terminals (or ports) that are labeled as121(which may be a respective one of the terminals102ofFIG.3A) and123(which may be connected to a respective one of the PA switch circuits103ofFIG.3A) inFIG.3B. In some embodiments, the source of power (from the power amplifier or PA) is connected to terminal123and an adaptive load (e.g., an electromechanical switch or ASIC) is connected to terminal121. In some embodiments, the adaptive load is formed generally as a complex impedance which may have both real and imaginary parts (i.e., a complex adaptive load can be formed using active devices (e.g., integrated circuits or chips made of transistors) or passive devices formed by inductors/capacitors and resistors). In some embodiments, the complex impedance is given by the formula Z=A+jB (e.g., 0+j0, 100+j0, 0+50j, and etc.), as discussed above. In some embodiments, the receiver104may also be considered as a third terminal. To eliminate wasted energy, the receiver104should be configured to absorb a maximum amount (e.g., 75% or more, such as 98%) of the induced power that travels from terminal123and towards terminal121. In some embodiments, processor110is connected to the receiver104through a feedback loop (e.g., by exchanging messages using a short-range communication protocol, such by BLUETOOTH low energy (BLE) to exchange messages). In some alternative embodiments, the feedback loop from the receiver back to the CPU at the transmitter may utilize a same frequency band as the power transmission signals transmitted by the pad100, rather than using a separate communication protocol and/or a different frequency band. In some embodiments, the feedback loop and messages exchanged may be used to indicate an amount of energy received or alternatively or additionally may indicate an increase or decrease in the amount of energy received as compared to previous measurements. In some embodiments, the processor110monitors the amount of energy received by the receiver104at certain points in time and controls/optimizes the adaptive load to maximize the power transferred from terminal123to terminal121. In some embodiments, monitoring the amount of energy transferred includes one or both of (i) receiving information from the receiver104(or a component of an electronic device in which the receiver104is located) that indicates an amount of energy received by the receiver104at a certain point in time and (ii) monitoring an amount of energy that remains in the conductive line at terminal121(instead of having been absorbed by the receiver104). In some embodiments, both of these monitoring techniques are utilized while, in other embodiments, one or the other of these monitoring techniques is utilized. In some embodiments, the receiver104(i.e., an electronic device that includes the receiver104as an internally or externally connected component) may be placed anywhere on top of the charging pad100(i.e., partially or fully covering the conductive line that forms a meandered pattern on a respective antenna element120) and the processor110will continue to monitor the amount of energy transferred and make needed adjustments (e.g., to impedance and/or frequency) to maximize the energy transferred to the receiver104. To help illustrate operation of the charging pad100and the antenna elements120included therein, the transmitting antenna element120shown inFIG.3Bis divided into two sections: 1) section125starts at the terminal123of the antenna element120and extends to an edge of the receiver104; and 2) section127is formed by the rest of the transmitting antenna element120and the terminal121. The blocks are described in more detail below with respect toFIG.3C. It should be understood that sections125and127are functional representations used for illustrative purposes, and they are not intended to designate a specific implementation that partitions an antenna element into separate sections. Turning now toFIG.3C, a block diagram of the TX antenna120is shown. In some embodiments, an effective impedance value (Zeffective), starting from a point that divides sections125and127and ending at the TX antenna120's connection to the adaptive load106(e.g., terminal121) will change based on location of the receiver104on the TX antenna120and based on a selected load provided by adaptive load106at the terminal121. In some embodiments, the selected load is optimized by the adaptive load106(in conjunction with the processor110,FIG.3A) to tune Zeffective in such a way that the energy transferred between terminal123and the receiver104reaches a maximum (e.g., 75% or more of energy transmitted by antenna elements of the pad100is received by the RF receiver104, such as 98%), while energy transfer may also stay at a minimum from terminal123to terminal121(e.g., less than 25% of energy transmitted by antenna elements of the pad100is not received by the RF receiver104and ends up reaching terminal121or ends up being reflected back, including as little as 2%). In embodiments in which an electromechanical switch (e.g., a mechanical relay) is used to switch between open and shorted states, moving the switch from the open to the shorted state (e.g., shorted to a ground plane) for a particular antenna element120causes the impedance value, Zeffective, at a respective terminal121for that particular antenna element120to drop to a value close to 0 (alternatively, switching from the shorted to the open state causes the impedance value to jump close to a value close to infinity). In some embodiments, the frequency adaptation scheme discussed above in reference toFIG.3Ais employed to test various combinations of impedance values and RF signal frequencies, in order to maximize energy transferred to an RF receiver (e.g., receiver104,FIGS.3A-3C). In some embodiments, an integrated circuit (IC or chip) may be used instead of an electromechanical switch as the adaptive load106. In such embodiments, the adaptive load106is configured to adjust the impedance value along a range of values, such as between 0 and infinity. In some embodiments, the IC may be formed by adaptive/reconfigurable RF active and/or passive elements (e.g., transistors and transmission lines) that are controlled by firmware of the IC (and/or firmware executing on the CPU110that controls operation of the IC). In some embodiments, the impedance produced by the IC, and controlled through firmware and based on information from the feedback loop (discussed above in reference toFIG.3A), may be changed to cover any load values selected from a Smith Chart (or the IC may be designed to produce certain loads covering a portion of values form the Smith Chart). In some embodiments, this IC is distinct from the RF power transmitter integrated circuit160(FIG.1B) that is used to manage overall operation of the pad100, and this other IC is also in communication with the RF power transmitter integrated circuit160to allow the circuit160to control adjustments to impedance values. A Smith Chart may be sampled and stored in a memory (e.g., as a lookup table) that is accessible by the processor110, and the processor110may perform lookups using the stored Smith Chart to determine various impedance values to test. For example, the integrated circuit may be configured to select a predetermined number of complex values (e.g., 5j to 10j, 100+0j, or 0+50j, etc.) for the impedance value to test in combination with various RF transmission frequencies, in order to locate a combination of values that optimizes energy transferred to the receiver104(examples of maximized energy transfer are discussed above). In some other embodiments, a transmitter or charging pad with more than one antenna elements120ofFIG.1Bwith one adaptive load106may be configured to operate in two or more distinct frequency bands respectively at the same time. For example, a first antenna element operates at a first frequency or frequency band, a second antenna element operates at a second frequency or frequency band, and a third antenna element operates at a third frequency or frequency band, and a fourth antenna element operates at a fourth frequency or frequency band, and the four frequency bands are distinct from each other. A transmitter with two or more antenna elements120therefore can be used as a multi-band transmitter. FIG.3Dis a block diagram of a simplified circuit that illustrates energy flow within sections of an antenna element that is transmitting an RF signal, in accordance with some embodiments. The references to part′ and part2inFIG.3Drefer to sections illustrated inFIGS.3B and3C, in particular, part′ corresponds to section125and part2corresponds to section127. As shown inFIG.3D, the effective impedance (Zeffective) for a transmitting antenna element120is formed by the portion of the conductive line that is after the receiver104(which, in some embodiments, forms a meandered line pattern as discussed in more detail below) and the adaptive load (labelled to as section127inFIGS.3B and3C). In some embodiments, by optimizing, the load Zeffectivewill be tuned so the energy transferred from PA to the receiver104is maximized; and, the energy remaining in the conductive line by the time it reaches the adaptive load is minimized (as discussed above). FIG.4is a schematic of an antenna element with two terminals, in accordance with some embodiments. As shown inFIG.4, an input or first terminal of the antenna element120(also described as terminal123in reference toFIGS.3B-3Dabove) is connected with a power amplifier108and an output or second terminal (also described as terminal121in reference toFIGS.3B-3Dabove) is connected with a load pick106that allows for configuring an adaptive load. Stated another way, in some embodiments, the antenna element120is fed by the power amplifier108from the first terminal and the antenna element120is also terminated at a second terminal at an adaptive load (for example, the mechanical relay that switches between shorted and open states). In some embodiments, the charging pad100(FIG.3A) is made of single-layer or multi-layer copper antenna elements120with conductive lines that form a meandered line pattern. In some embodiments, each of these layers has a solid ground plane as one of its layers (e.g., a bottom layer). One example of a solid ground plane is shown and labelled for the transmitting antenna element shown inFIG.4. In some embodiments, the RF charging pad100(and individual antenna elements120included therein) is embedded in a consumer electronic device, such as a projector, a laptop, or a digital media player (such as a networked streaming media player, e.g. a ROKU device, that is connected to a television for viewing streaming television shows and other content). For example, by embedding the RF charging pad100in a consumer electronic device, a user is able to simply place a peripheral device, such as a remote for a projector or a streaming media player (e.g., the remote for the projector or streaming media player includes a respective receiver104, such as the example structures for a receiver104shown inFIGS.7A-7D), on top of the projector or the streaming media player and the charging pad100included therein will be able to transmit energy to a receiver104that is internally or externally connected to the remote, which energy is then harvested by the receiver104for charging of the remote. In some embodiments, the RF charging pad100may be included in a USB dongle as a standalone charging device on which a device to be charged is placed. In some embodiments, the antenna elements120may be placed near a top surface, side surfaces, and/or a bottom surface of the USB dongle, so that a device to be charged may be placed at various positions that contact the USB dongle (e.g., a headphone that is being charged might sit on top of, underneath, or hang over the USB dongle and would still be able to receive RF transmissions from the embedded RF charging pad100). In some embodiments, the RF charging pad100is integrated into furniture, such as desks, chairs, countertops, etc., thus allowing users to easily charge their devices (e.g., devices that includes respective receivers104as internally or externally connected components) by simply placing them on top of a surface that includes an integrated RF charging pad100. Turning now toFIG.5, a flowchart of a method500of charging an electronic device through radio frequency (RF) power transmission is provided. Initially, a transmitter is provided502that includes at least one RF antenna (e.g., antenna element120,FIGS.3B-3D and4) for transmitting one or more RF signals or waves, i.e., an antenna designed to and capable of transmitting RF electromagnetic waves. In some embodiments, an array of RF antenna elements120are arranged adjacent to one another in a single plane, in a stack, or in a combination of thereof, thus forming an RF charging pad100. In some embodiments, the RF antenna elements120each include an antenna input terminal (e.g., the first terminal123discussed above in reference toFIG.4) and an antenna output terminal (e.g., the second terminal121discussed above in reference toFIG.4). In some embodiments, a receiver (e.g., receiver104,FIGS.3A-3D) is also provided504. The receiver also includes one or more RF antennas for receiving RF signals310. In some embodiments, the receiver includes at least one rectenna that converts318the one or more RF signals into usable power to charge a device that includes the receiver104as an internally or externally connected component. In use, the receiver104is placed506within a near-field radio frequency distance to the at least one antenna. For example, the receiver may be placed on top of the at least one RF antenna or on top of a surface that is adjacent to the at least one RF antenna, such as a surface of a charging pad100. One or more RF signals are then transmitted508via at the least one RF antenna. The system is then monitored512/514to determine the amount of energy that is transferred via the one or more RF signals from the at least one antenna to a RF receiver (as is also discussed above). In some embodiments, this monitoring512occurs at the transmitter, while in other embodiments the monitoring514occurs at the receiver which sends data back to the transmitter via a back channel (e.g., over a wireless data connection using WIFI or BLUETOOTH). In some embodiments, the transmitter and the receiver exchange messages via the back channel, and these messages may indicate energy transmitted and/or received, in order to inform the adjustments made at step516. In some embodiments, a characteristic of the transmitter is adaptively adjusted at step516to attempt to optimize the amount of energy that is transferred from the at least one RF antenna to the receiver. In some embodiments, this characteristic is a frequency of the one or more RF signals and/or an impedance of the transmitter. In some embodiments, the impedance of the transmitter is the impedance of the adjustable load. Also in some embodiments, the at least one processor is also configured to control the impedance of the adaptive load. Additional details and examples regarding impedance and frequency adjustments are provided above. In some embodiments, the transmitter includes a power input configured to be electrically coupled to a power source, and at least one processor (e.g., processor110,FIGS.3A-3B) configured to control at least one electrical signal sent to the antenna. In some embodiments, the at least one processor is also configured to control the frequency of the at least one signal sent to the antenna. In some embodiments, the transmitter further comprises a power amplifier electrically coupled between the power input and the antenna input terminal (e.g., PA108,FIGS.3A,3B,3D, and4). Some embodiments also include an adaptive load electrically coupled to the antenna output terminal (e.g., terminal121,FIGS.3A-3C and4). In some embodiments, the at least one processor dynamically adjusts the impedance of the adaptive load based on the monitored amount of energy that is transferred from the at least one antenna to the RF receiver. In some embodiments, the at least one processor simultaneously controls the frequency of the at least one signal sent to the antenna. In some embodiments, each RF antenna of the transmitter includes: a conductive line forming a meandered line pattern, a first terminal (e.g., terminal123) at a first end of the conductive line for receiving current that flows through the conductive line at a frequency controlled by one or more processors, and a second terminal (e.g., terminal121), distinct from the first terminal, at a second end of the conductive line, the second terminal coupled to a component (e.g., adaptive load106) controlled by the one or more processors and that allows for modifying an impedance value of the conductive line. In some embodiments, the conductive line is disposed on or within a first antenna layer of a multi-layered substrate. Also in some embodiments, a second antenna is disposed on or within a second antenna layer of the multi-layered substrate. Finally, some embodiments also provide a ground plane disposed on or within a ground plane layer of the multi-layered substrate. In some embodiments, the method described above in reference toFIG.5is performed in conjunction with the methods described below in reference toFIGS.9A-9B,10, and11A-11E. For example, the operations of modifying/adjusting impedance values are performed after determining which antenna zones (the “determined antenna zones”) to use for transmitting wireless power to a receiver, and then impedance values at the determined antenna zones are adjusted to ensure that a maximum amount of power is transferred wirelessly to the receiver by antennas within the determined antenna zones. FIGS.6A-6Eare schematics showing various configurations for individual antenna elements within an RF charging pad, in accordance with some embodiments. As shown inFIGS.6A-6E, an RF charging pad100(FIG.3A) may include antenna elements120that are made using different structures. For example,FIGS.6A-6Bshow examples of structures for an antenna element120that includes multiple layers that each include conductive lines formed into meandered line patterns. The conductive lines at each respective layer may have the same (FIG.6B) or different (FIG.6A) widths (or lengths, or trace gauges, or patterns, spaces between each trace, etc.) relative to other conductive lines within a multi-layer antenna element120. In some embodiments, the meandered line patterns may be designed with variable lengths and/or widths at different locations of the pad100(or an individual antenna element120), and the meandered line patterns may be printed on more than one substrate of an individual antenna element120or of the pad100. These configurations of meandered line patterns allow for more degrees of freedom and, therefore, more complex antenna structures may be built that allow for wider operating bandwidths and/or coupling ranges of individual antenna elements120and the RF charging pad100. Additional example structures are provided inFIGS.6C-6E:FIG.6Cshows an example of a structure for an antenna element120that includes multiple layers of conductive lines forming meandered line patterns that also have sliding coverage (in some embodiments, respective meandered line patterns may be placed in different substrates with just a portion of a first meandered line pattern of a respective substrate overlapping the a second meandered line pattern of a different substrate (i.e., sliding coverage), and this configuration helps to extend coverage throughout width of the antenna structure);FIG.6Dshows an example of a structure for an antenna element120that includes a conductive line having different lengths at each turn within the meandered line pattern (in some embodiments, using different lengths at each turn helps to extend coupling range of the antenna element120and/or helps add to the operating bandwidth of the RF charging pad100); andFIG.6Eshows an example of a structure for an antenna element120that includes a conductive line that forms two adjacent meandered line patterns (in some embodiments, having a conductive line that forms two adjacent meandered line patterns helps to extend width of the antenna element120). All of these examples are non-limiting and any number of combinations and multi-layered structures are possible using the example structures described above. FIGS.7A-7Dare schematics of an antenna element for an RF receiver, in accordance with some embodiments. In particularFIGS.7A-7Dshow examples of structures for RF receivers (e.g., receiver104,FIGS.3A-3D and4), including: (i) a receiver with a conductive line that forms meandered line patterns (the conductive line may or may not be backed by solid ground plane or reflector), as shown inFIGS.7A(single-polarity receiver) and7B (dual-polarity receiver).FIGS.7C-7Dshow additional examples of structures for an RF receiver with dual-polarity and a conductive line that forms a meandered line pattern. Each of the structures shown inFIGS.7A-7Dmay be used to provide different coupling ranges, coupling orientations, and/or bandwidth for a respective RF receiver. As a non-limiting example, when the antenna element shown inFIG.7Ais used in a receiver, very small receivers may be designed/built that only couple to the pad100in one direction. As another non-limiting example, when the antenna elements shown inFIGS.7B-7Dare used in a receiver, the receiver is then able to couple to the pad100in any orientation. Other examples and descriptions of meandered line patterns for antenna elements are provided below.FIG.8is a schematic of an RF charging pad with a plurality of transmitting antenna elements (unit cells) that form a larger RF charging/transmitting pad, in accordance with some embodiments. In some embodiments, the RF charging pad100is formed as an array of adjacent antenna elements120(the distance between cells may be optimized for the best coverage). In some embodiments, when a receiver is placed in an area/gap that is between adjacent antenna elements120, attempts to optimize energy transfer (e.g., in accordance with the adaptation scheme discussed above in reference toFIG.3A) may not result in increased energy transfer above an acceptable threshold level (e.g., 75% or more). As such, in these circumstances, adjacent antenna elements may both be configured to transmit RF waves at full power at the same time to transfer additional energy to a receiver that is placed on a surface of the RF charging pad, and at a location that is between adjacent antenna elements120. As one possible configuration in accordance with some embodiments, port (or terminal) group #1(FIG.8) supplies power, port (or terminal) groups #2and #3provide adaptive loads (e.g., an electromechanical relay moving between short-circuit and open-circuit states). As another example of a suitable configuration, port (or terminal) groups #1, #2and #3may also be used to supply power via a power amplifier to the charging pad100(at the same time or with one group at a time being switched when necessary). In some embodiments, each transmitting antenna element120of the RF charging pad100forms a separate antenna zone which is controlled by a feeding (PA) terminal and one or more terminals to support adaptive load(s), as explained in detail above. In some embodiments, feedback from the receiver helps determine the antenna zone on top of which the receiver is placed, and this determination activates that zone (e.g., using the switch295,FIG.1C). In circumstances in which the receiver is placed between two or more zones (e.g., at an area/gap that is between adjacent antenna elements120), additional adjacent zones might be activated to ensure sufficient transfer of energy to the receiver. Additional details regarding determining zones to use for transmitting wireless power to the receiver are provided below in reference toFIGS.9A-9B,10, and11A-11E. FIGS.9A-9Bare flow diagrams showing a method900of selectively activating one or more antenna zones (e.g., activating the antennas associated therewith) in a near-field charging pad, in accordance with some embodiments. Operations of the method900are performed by a near-field charging pad (e.g. RF charging pad100,FIGS.1B and2A) or by one or more components thereof (e.g., those described above with reference toFIGS.1A-1B and2A). In some embodiments, the method900corresponds to instructions stored in a computer memory or computer-readable storage medium (e.g., memory206of the RF charging pad100,FIG.2A). The near-field charging pad includes one or more processors (e.g., CPU202,FIG.1B), a wireless communication component (e.g., communication component(s)204,FIGS.1A and2A), and a plurality of antenna zones (e.g., antenna zones290-1and290-N,FIG.1B) that each respectively include at least one antenna element (e.g., one of antennas210, which may be one of the antennas120described in reference toFIGS.3A-6E) (902). In some embodiments, the near-field charging pad includes distinct antennas (or unit cells including antennas, also referred to herein as antenna elements) that are each included in respective antenna zones. For example, as shown inFIG.1B, an antenna zone290-1includes an antenna210-A. In another example, as is also shown inFIG.1B, an antenna zone290-N includes multiple antennas. The antenna zones may also be referred to as antenna groups, such that the near-field charging pad includes a plurality of antenna zones or groups, and each respective zone/group includes at least one of the distinct antenna elements (e.g., at least one antenna210). It should be noted that an antenna zone can include any number of antennas, and that the numbers of antennas associated with a particular antenna zone may be modified or adjusted (e.g., the CPU subsystem170of RF power transmitter integrated circuit160responsible for managing operations of the near-field charging pad100dynamically defines each antenna zone at various points in time, as is discussed in more detail below). In some embodiments, each antenna zone includes a same number of antennas. In some embodiments, the one or more processors are a component of a single integrated circuit (e.g., RF power transmitter integrated circuit160,FIG.1B) that is used to control operation of the near-field charging pad. In some embodiments, the one or more processors and/or the wireless communication component of the near-field charging pad is/are external to the near-field charging pad, such as one or more processors of a device in which the near-field charging pad is embedded. In some embodiments, the wireless communication component is a radio transceiver (e.g., a BLUETOOTH radio, WI-FI radio, or the like for exchanging communication signals with wireless power receivers). In some embodiments, the method includes establishing (904) one or more device detection thresholds during a calibration process for the near-field charging pad. In some instances, the calibration process is performed after manufacturing the near-field charging pad and includes placing devices of various types (e.g., smartphones, tablets, laptops, connected devices, etc.) on the near-field charging pad and then measuring a minimum amount of reflected power detected at an antenna zone while transmitting test power transmission signals to the devices of various types. In some instances, a first device-specific threshold is established at a value corresponding to 5% or less of the minimum amount of reflected power. In some embodiments, a second device-specific threshold is also established so that if no one antenna zone is able to satisfy the first threshold (e.g., because the wireless power receiver is located at a border between antenna zones), then the second, higher threshold may be used to locate more than one antenna zone to use for transmitting power to the wireless power receiver (as discussed in more detail below). In some embodiments, multiple first and second device-specific detection thresholds are established for each type of device of the various types, and these multiple first and second device-specific detection thresholds may be stored in a memory associated with the RF power transmitter integrated circuit160(e.g., memory206,FIG.2A). The method900also includes detecting (906), via the wireless communication component, that a wireless power receiver is within a threshold distance of the near-field charging pad. In some instances, the detecting may occur after the near-field charging pad is turned on (e.g., powered up). In these instances, the near-field charging pad scans an area around the near-field charging pad (e.g., to scan for wireless power receivers that are located within the threshold distance, e.g., within 1-1.5 meters, away from the NF charging pad100) to determine whether any wireless power receivers are within the threshold distance of the NF charging pad100. The near-field charging pad may use the wireless communication component (e.g., communication component(s)204,FIG.2A, such as a Bluetooth radio) to conduct the scanning for signals broadcasted by wireless communication components associated with wireless power receivers (e.g., communication component254,FIG.2B). In some embodiments, the device detection threshold is selected (from among the multiple first and second device detection threshold discussed above) by the one or more processors after detecting the wireless power receiver within the threshold distance of the near-field charging pad. For example, a wireless communication component of the wireless power receiver is used to provide information to the near-field charging pad that identifies the type of device, such as a BLUETOOTH or BLUETOOTH low energy advertisement signal that includes this information. In some embodiments, to save energy and prolong life of the near-field charging pad and its components, no wireless power is transmitted (and the device detection and antenna selection algorithms discussion herein are not initiated) until a wireless power receiver is detected within the threshold distance of the near-field charging pad. In some embodiments, the detecting906also includes performing an authorization handshake (e.g., using the secure element modules234and282,FIGS.2A and2B) to ensure that the wireless power receiver is authorized to receive wirelessly delivered power from the near-field charging pad and the method only proceeds to operation908if it is determined that the wireless power receiver is so authorized. In this way, the near-field charging pad ensures that only authorized wireless power receivers are able to receive wirelessly delivered power and that no device is able to leech power that is transmitted by the near-field charging pad. The method900further includes, in response to detecting that the wireless power receiver is within the threshold distance of the near-field charging pad, determining (912) whether the wireless power receiver has been placed on the near-field charging pad. In some embodiments, this is accomplished by transmitting (908) test power transmission signals using each of the plurality of antenna zones and monitoring (910) an amount of reflected power at the near-field charging pad while transmitting the test power transmission signals. In some embodiments, if the amount of reflected power does not satisfy the device detection threshold (e.g., the amount of reflected power is greater than 20% of power transmitted with the test power transmission signals), then a determination is made that the wireless power receiver has not been placed on the surface of the near-field charging pad (912—No). In accordance with this determination, the near-field charging pad continues to transmit test power transmission signals using each of the plurality of antenna zones at step914(i.e., proceed to step908). In some embodiments, the operations at908and910are performed until it is determined that the device detection threshold has been satisfied. In some embodiments, the amount of reflected power is measured at each antenna zone of the plurality of antenna zones (e.g., each antenna zone may be associated with a respective ADC/DAC/Power Detector, such as the one shown inFIG.1B) while, in other embodiments, the amount of reflected power may be measured using a single component of the RF power transmitter integrated circuit160(e.g., the ADC/DAC/Power Detector). When the amount of reflected power satisfies the device detection threshold (912—Yes), the wireless power receiver is determined to have been placed on the near-field charging pad. For example, the amount of reflected power may satisfy the device detection threshold when the amount of reflected power is 20% or less than amount of power transmitted with the test power transmission signals. Such a result indicates that a sufficient amount of the power transmitted with the test power transmission signals was absorbed/captured by the wireless power receiver. In some embodiments, other types of sensors (e.g., sensors212,FIG.2A) are included in or in communication with the near-field charging pad to help determine when the wireless power receiver has been placed on the near-field charging pad. For example, in some embodiments, one or more optical sensors (e.g., when light is blocked from a part of the pad, then this may provide an indication that the wireless power receiver has been placed on the pad), one or more vibration sensors (e.g., when a vibration is detected at the pad, then this may provide an indication that the wireless power receiver has been placed on the pad), one or more strain gauges (e.g., when a strain level at a surface of the pad increases, this may provide an indication that the wireless power receiver has been placed on the surface), one or more thermal sensors (e.g., when a temperature at a surface of the pad increases, this may provide an indication that the wireless power receiver has been placed on the surface), and/or one or more weighing sensors (e.g., when an amount of weight measured on the surface of the pad increases, then this may provide an indication that the wireless power receiver has been placed on the surface) are utilized to help make this determination. In some embodiments, before transmitting the test power transmission signals, the method includes determining that the wireless power receiver is authorized to receive wirelessly delivered power from the near-field charging pad. For example, as shown inFIGS.2A-2B, the wireless power receiver104and the near-field charging pad100may include secure element modules282and234, respectively, which are used to perform this authorization process, thereby ensuring that only authorized receivers are able to receive wirelessly delivered power from the near-field charging pad. The method900further includes, in accordance with determining that the wireless power receiver has been placed on the near-field charging pad, selectively transmitting (916), by respective antenna elements included in the plurality of antenna zones, respective test power transmission signals with a first set of transmission characteristics. In some embodiments, the selectively or sequentially transmitting is performed using each antenna zone of the plurality of antenna zones (918). Selectively or sequentially transmitting refers to a process of selectively activating antenna zones one at a time to cause one or more antennas associated with individual antenna zones to transmit test power transmission signals (e.g., the RF power transmitter integrated circuit160provides one or more control signals to the switch295to selectively activate different antenna zones). Referring now toFIG.9B, the method900further includes determining (920) whether a particular power-delivery parameter associated with transmission of a respective test power transmission signal (during the sequential or selective transmission operation at916and/or918) by at least one particular antenna zone of the plurality of antenna zones satisfies power-delivery criteria (e.g., whether the particular power-delivery parameter indicates that more than a threshold amount of power is transferred to the wireless power receiver by the at least one particular antenna zone). In some embodiments, each respective power-delivery parameter corresponds to an amount of power received by the wireless power receiver based on transmission of a respective test power transmission signal by a respective antenna group of the plurality of antenna groups. Upon determining, by the one or more processors, that the particular power-delivery parameter satisfies the power-delivery criteria (920—Yes), the method further includes transmitting (922) a plurality of additional power transmission signals to the wireless power receiver using the at least one particular antenna zone, where each additional power transmission signal of the plurality is transmitted with a second set of transmission characteristics, distinct from the first set. In some embodiments, the second set of transmission characteristics is determined by adjusting at least one characteristic in the first set of transmission characteristics to increase an amount of power that is transferred by the particular antenna group to the wireless power receiver. Moreover, in some embodiments, the at least one adjusted characteristic is a frequency or impedance value (and the frequency and impedance value may be adjusted using the adaptation scheme discussed above). The test power transmission signals discussed above are used to help determine which antenna zones to use for delivering wireless power to the wireless power receiver. In some embodiments, these test power transmission signals are not used by the wireless power receiver to provide power or charge to the wireless power receiver, or a device associated therewith. Instead, the plurality of additional power transmission signals is used to provide power or charge to the wireless power receiver. In this way, the near-field charging pad is able to preserve resources during a device detection stage (e.g., while transmitting the test power transmission signals) until a suitable antenna zone is located for transmitting the plurality of additional power transmission signals. As such, the method900is able to locate a position of the wireless power receiver using test signals (i.e., the test power transmission signals with the first set of transmission characteristics) and then transmit using antenna from an antenna zone that is best-suited to provide power transmission signals given the position of the wireless power receiver on the near-field charging pad. As discussed in more detail below with reference toFIG.10, this process may include a coarse search for antenna zones (e.g., the coarse search may include the operations908-918) and a finer search for antenna zones (e.g., the finer search may include operations920-934). In some embodiments, a power control process (FIG.11E) is also used to help optimize a level of power delivered to the wireless power receiver using the selected antenna zones (e.g., power control may be performed after operations922,930, or934to tune transmission of wireless power using the antenna zones that were selected during the method900). As a part of the power control process, the near-field charging pad may, while transmitting the additional plurality of power transmission signals, adjust at least one characteristic in the second set of transmission characteristics based on information, received from the wireless power receiver, which is used to determine a level of power that is wirelessly delivered to the wireless power receiver by the near-field charging pad. Returning back to operation920, in response to determining that none of the power-delivery parameters associated with transmission of the test power transmission signals during the sequential or selective transmission operation(s) at916(and optionally918) satisfy the power-delivery criteria (920—No), the method900further includes selecting (924) two or more antenna zones (also referred to interchangeably herein as two+ antenna zones) based on their associated respective power-delivery parameters. This may arise when the wireless power receiver is not centered over any particular antenna zone (e.g., the receiver may be over more than one antenna zone). For example, the two or more antenna zones that transferred the highest amount of power to the wireless power receiver during the sequential or selective transmission operation at916(and optionally918) based on their respective power-delivery parameters are selected at operation924. In this way, in some embodiments, a finer search for the most efficient antenna zone is started by selecting the two or more antenna zones that most efficiently transmitted power to the wireless power receiver during the operations at916/918based on their respective association with power-delivery parameters that is higher than the power-delivery parameters for other antenna zones. In these embodiments, a respective power-delivery parameter may be monitored (in conjunction with operations916/918) for each antenna zone and these power-delivery parameters are then compared to determine which of the plurality of antenna zones to select as the two or more antenna zones to use for transmission of wireless power. After selecting the two or more antenna zones, the method further includes: (i) updating the test power transmission signals by modifying at least one characteristic of the test power transmission signals (e.g., frequency, impedance, amplitude, phase, gain, etc.), based on the previous transmissions (e.g., based on feedback received from the wireless power receiver regarding a level of power receive by the wireless power receiver or based on an amount of reflected power measured at each antenna group after the transmission), and (ii) transmitting (926) the updated test power transmission signals using each of the two or more antenna zones (e.g., the RF power transmitter integrated circuit160may provide one or more control signals to the switch295to activate the two or more antenna zones). The method900further includes determining (928) whether a particular power-delivery parameter associated with transmission of an updated respective test power transmission signal by a zone of the two or more antenna zones satisfies power-delivery criteria. In response to determining that the particular power-delivery parameter associated with transmission of the updated respective test power transmission signal by the zone of the two or more antenna zones satisfies the power-delivery criteria (928—Yes), the method900further includes transmitting (930) a plurality of additional power transmission signals to the wireless power receiver using the zone of the two or more antenna zones, where each additional power transmission signal of the plurality is transmitted with a second set of transmission characteristics, distinct from the first set (e.g., the RF power transmitter integrated circuit160may provide a control signal to the switch295). The plurality of additional power transmission signals is used to wirelessly deliver power to the wireless power receiver (or an electronic device coupled with the wireless power receiver). In some embodiments, the determination that the particular power-delivery parameter satisfies the power-delivery criteria at operations920and928may include determining that respective power-delivery parameters (associated with the at least one particular zone and/or the zone of the two or more antenna zones) indicates that a first threshold amount of power is transferred to the wireless power receiver. If such a determination is made at operation928, this indicates that the zone is the only antenna zone of the two or more antenna zones having a respective power-delivery parameter that indicates that the first threshold amount of power is transferred to the wireless power receiver by the zone in conjunction with operation926. In some embodiments, the first threshold amount of power corresponds to an amount of power received by the wireless power receiver (in some circumstances, the first threshold amount of power could alternatively correspond to an amount of reflected power detected at the near-field charging pad). As discussed above, in some embodiments, a calibration process is performed after manufacturing the near-field charging pad and includes placing devices of various types (e.g., smartphones, tablets, laptops, connected devices, etc., that are each coupled with wireless power receivers) on the near-field charging pad and then measuring a maximum amount of power received at the receiver (or device coupled thereto) after transmission of the test signal by an antenna group to the devices of various types. In some instances, the first threshold is established at a value corresponding to a percentage of the maximum amount of received power (e.g., approximately 85% or more of power transmitted by a particular antenna zone is received by the receiver). As explained above, during embodiments of the calibration process, a second threshold is also established so that if no one antenna zone is able to satisfy the first threshold (e.g., because the wireless power receiver may be located at a border between antenna groups) then the second threshold may be utilized to locate more than one antenna zone to transmit wireless power to the wireless power receiver (as discussed below). This second threshold may be another percentage of the maximum amount of reflected power that is measured during the calibration process (e.g., 65%). In some embodiments, the first and second thresholds are determined as respective device-specific first and second thresholds for each of the devices undergoing the calibration process. In some embodiments, the method900includes determining (928—No) that (i) no antenna zone of the two or more antenna zones is transferring the first threshold amount of power to the wireless power receiver and (ii) an additional power-delivery parameter associated with an additional antenna zone of the two or more antenna zones satisfies the power-delivery criteria. For example, a respective power-delivery parameter indicates that a first amount of power transferred to the wireless power receiver by the zone of the two or more zones is above a second threshold amount of power and below the first threshold amount of power, and the additional power-delivery parameter also indicates that a second amount of power transferred to the wireless power receiver by the additional antenna zone is above the second threshold amount of power and below the first threshold amount of power. In other words, if no antenna zone of the two or more antenna zones is able to transfer enough power to the wireless power receiver to satisfy the first threshold amount of power, then the method proceeds to determine whether two of the antenna groups transferred enough power to the wireless power receiver to satisfy a second, lower threshold amount of power. For example, the wireless power receiver may be located at a border between two antenna groups, so no one antenna group is able to satisfy the first threshold, but these two antenna groups may be able to each individually satisfy the second threshold amount of power. Upon determining, by the one or more processors of the near-field charging pad, that the power-delivery parameters associated with transmission of the updated test power transmission signals by the two or more antennas zones satisfy the power-delivery criteria (932—Yes), the method further includes transmitting (934) a plurality of additional power transmission signals to the wireless power receiver using the two or more antenna zones. Such a situation may arise when the wireless power receiver is placed between two adjacent antenna zones. In some embodiments, the two or more antenna zones each simultaneously transmit the additional plurality of power transmission signals to provide power to the wireless power receiver. As is also shown inFIG.9B, if the two or more zones do not have power-delivery parameters that satisfy the power-delivery criteria (932—No), then the method900returns to operation906to start searching for the receiver (or a different receiver again), as no antenna zones were located that could efficiently transfer wireless power to the receiver. In some embodiments, the method900may alternatively return to operation924to begin transmitting test power transmission signals with different characteristics to determine if those characteristics are able to then allow the two or more antenna zones to deliver enough wireless power to the receiver to satisfy the power-delivery criteria. In some embodiments, the method900returns to operation924a predetermined number of times (e.g., 2) and, if the two or more zones still do not have power-delivery parameters that satisfy the power-delivery criteria, then the method at that point returns to operation906to begin searching for new receivers. In some embodiments, after the method900successfully locates antenna zones to use for wirelessly delivering power to the receiver (e.g., at operations922,930, and934) then the method900returns to operation906to being search for new receivers. The near-field charging pad, in some embodiments, is capable of simultaneously delivering wireless power to multiple receivers at any particular point in time and, therefore, iterating through the method900again allows the near-field charging pad to appropriately determine which antenna zones to use for transmission of wireless power to each of these multiple receivers. In some embodiments, information used to determine respective power-delivery parameters for each of the antenna zones of the near-field charging pad is provided to the near-field charging pad by the wireless power receiver via the wireless communication component of the near-field charging pad (e.g., the receiver transmits information that is used to determine an amount of power received by the receiver from the test power transmission signals discussed above). In some embodiments, this information is sent via a connection between the wireless communication component of the near-field charging pad and the wireless power receiver, and the connection is established upon determining that the wireless power receiver has been placed on the near-field charging pad. Additionally, in some embodiments, the near-field charging pad dynamically creates or defines antenna zones. For example, with reference toFIG.1B, the near-field charging pad may define a first antenna zone290-1to include a single antenna210-A and may define another antenna zone290-N to include more than one antenna210. In some embodiments, at various phases of the method900discussed above, antenna zones may be redefined. For example, in accordance with the determination that the two or more antenna zones do not have power-delivery parameters that satisfy the power-delivery criteria (932—No), the near-field charging pad may redefine the antenna zones to each include multiple antennas (instead of having each antenna zone include a single antenna). In this way, the method900is able to dynamically define antenna zones to help ensure that an appropriate antenna zone is located that may be used to transmit wireless power to a receiver that has been placed on the near-field charging pad. FIG.10is an overview showing a process1000of selectively activating one or more antenna groups in a near-field charging pad, in accordance with some embodiments. Some of the operations in process1000correspond to or supplement the operations describe above in reference to method900ofFIGS.9A-9B. As shown inFIG.10, the process1000begins with a near-field charging pad (e.g., RF charging pad100,FIGS.1A-1B and2A) detecting (1002) a wireless power receiver (e.g., wireless power receiver104,FIG.12B) in range and subsequently on the near-field charging pad (operation1002corresponds to operations906to912—Yes inFIG.9A). The process1000further includes performing (1004) a coarse search, performing (1006) a fine search, and executing (1008) a power control routine. Each step in the process1000is described in further detail below with reference toFIGS.11A-11E. It should be noted that the process1000, in some embodiments, begins with the near-field charging pad detecting (1002) a wireless power receiver on the near-field charging pad and subsequently in range of the near-field charging pad. FIG.11Ais a flowchart detailing a process1002for detecting a wireless power receiver in range and subsequently on the near-field charging pad (or in some embodiments, on the near-field charging pad and subsequently in range of the near-field charging pad). The process1002includes enabling the near-field charging pad (1102), i.e., powering on the near-field charging pad. Thereafter, the near-field charging pad scans (1104) for wireless power receivers and detects (1106) a wireless power receiver in range based, at least in part, on a received signal strength indicator (RSSI). To obtain the RSSI, the near-field charging pad may use a wireless communication component (e.g., communication component(s)204,FIG.2A, such as a Bluetooth radio) to scan for signals broadcasted by wireless communication components associated with wireless power receivers (e.g., a Bluetooth advertisement signal). Detecting a wireless power receiver in range of the near-field charging pad is discussed in further detail above with reference to operation906of the method900. Next, the near-field charging pad detects (1108) a wireless power receiver on the near-field charging pad. In some embodiments, the near-field charging pad establishes that the wireless power receiver is on the near-field charging pad using the processes discussed above in reference to operations908-914until it is determined that the wireless power receiver has been placed on the near-field charging pad. In some embodiments, operation (1108) occurs before operation (1102). Continuing, the near-field charging pad establishes (1110) a communication channel with the wireless power receiver in response to detecting the wireless power receiver on the near-field charging pad. Turning now toFIG.11B, the method proceeds to process1004in which the near-field charging pad performs a coarse search (1004). In performing the coarse search1004, the near-field charging pad begins by enabling (1122) power for an antenna zone (e.g., antenna zone290-1,FIG.1B). In some embodiments, enabling power for the antenna zone includes transmitting, by an antenna element included in the antenna zone (e.g., after the RF power transmitter integrated circuit160provides one or more control signals to the switch295to activate the antenna zone), test power transmission signals with a first set of transmission characteristics (e.g., phase, gain, direction, amplitude, polarization, and/or frequency). Transmitting test power transmission signals is discussed in further detail above with reference to steps916-918of the method900. Continuing with the coarse search1004, the near-field charging pad records (1124) an amount of power received by the wireless power receiver (the “reported power”). In some embodiments, the reported power is communicated to the near-field charging pad by the wireless power receiver via the communication channel that was established at operation1110. The near-field charging pad repeats (1126) steps (1122) and (1124) above for all antenna zones that have been defined for the near-field charging pad (e.g., RF power transmitter integrated circuit160provides one or more control signals to the switch295to selectively activate all the antenna zones). Thereafter, in some embodiments, the near-field charging pad selects (1128) a set of antenna zones based on the reported power (e.g., 2 or 3 zones, or some greater or lesser number, depending on the circumstances) and a configured threshold (e.g., power-delivery criteria). For ease of discussion, each antenna zone in the set includes a single antenna210(e.g., antenna zone290-1,FIG.1B). However, it should be understood that instead of selecting a set of antenna zones, the near-field charging pad could also select a single antenna zone that includes multiple antennas210. For example, as shown inFIG.1B, the antenna zone290-N includes multiple antennas210. In addition, each antenna zone in the set could also include multiple antennas, depending on the circumstances. Turning now toFIG.11C, after selecting the set of antenna zones based on the reported power, the near-field charging pad performs the fine search process (1006). In some embodiments, the fine search1006is used to determine which antenna zone(s) is/are best suited to wirelessly delivery power to the wireless power receiver, based on a location of the wireless power receiver on the near-field charging pad. In performing the fine search (1006), the near-field charging pad selects (1132) at least one antenna zone from the set of antenna zones selected using the coarse search, and for the at least one antenna zone, the near-field charging pad sweeps (1134) across available frequencies and/or impedances (i.e., tunes transmission of power transmission signals by the at least one antenna zone). Thereafter, the near-field charging pad records (1136) those characteristics that result in maximizing an amount of received power reported by the wireless power receiver. In some embodiments, operations1134and1136are repeated for each antenna zone in the set of antenna zones (1138) and the near-field charging pad selects (1140) an antenna zone (Z1) that delivers a maximum amount of power to the wireless power receiver. In addition, the near-field charging pad also records the frequency (and other transmission characteristics) and a relay position by antenna zone Z1to achieve the delivery of the maximum amount of power to the wireless power receiver. In some circumstances or situations, the amount of power delivered to the wireless power receiver by the antenna zone Z1does not meet a threshold amount of power. In these circumstances or situations, the near-field charging pad performs an adjacent zone search (1007), which is illustrated inFIG.11D. In some embodiments, the adjacent zone search1007is used to identify one or more adjacent zones to the selected antenna zone Z1that may be activated (e.g., the RF power transmitter integrated circuit160provides one or more control signals to the switch295) in order to increase an amount of power delivered to the wireless power receiver. For example, this may occur when the wireless power receiver is located at a border between adjacent antenna zones of the near-field charging pad (e.g., located at an intersection between two antenna zones, three antenna zones, or four antenna zones). In performing the adjacent zone search1007, the near-field charging pad identifies (1142) adjacent antenna zones (ZAs) to the selected antenna zone Z1. In some embodiments, identifying adjacent zones (ZAs) includes identifying up to five adjacent zones. Next, the near-field charging pad pairs (1144) the selected antenna zone Z1with each identified adjacent zone and sweeps (1146) across all antenna tuning combinations and sweeps (1148) across all available frequencies (and perhaps other transmission characteristics). Thereafter, the near-field charging pad selects (1150) a combination of antenna zones from among the adjacent zones (ZAs). For example, the near-field charging pad may determine that the selected antenna zone Z1deliver a higher amount of power to the wireless power receiver than either of these antenna zones is individually able to deliver to the wireless power receiver. In another example, the near-field charging pad may determine that the selected antenna zone Z1and two (or three) other adjacent zones deliver a maximum amount of power to the wireless power receiver. When selecting the desired combination of antenna zones, the near-field charging pad records the transmission characteristics used to produce the maximum amount of power delivered to the wireless power receiver. Performing the fine search and the adjacent zone search are also discussed in more detail above with reference to steps924-932of the method900. After performing the fine search1006(and the adjacent zone search1007if needed), the near-field charging pad executes (1008) a power control routine, an example of which is illustrated inFIG.11E. In some embodiments, the power control routine allows both the wireless power receiver and the near-field charging pad to continually monitor an amount of power being delivered to the wireless power receiver. In this way, adjustments to the wireless power transmission can be made based on feedback received from the wireless power receiver. For example, if the delivered power is below a configured threshold, then the wireless power receiver may request a power increase from the near-field charging pad.FIG.11Eillustrates various operations that may be used to allow the receiver to request an increase or a decrease in an amount of wireless power delivered to the receiver, and also illustrates a process executed by the near-field charging pad to determine when to increase or decrease the amount of wireless power delivered to the receiver in response to the receiver's requests for increases or decreases in the amount of wireless power delivered. The antenna elements120described above (e.g., in reference toFIG.1B) may also be configured to have multiple adaptive load terminals (e.g., multiple adaptive load terminals121) that are coupled to at different positions along a respective antenna element120. An example of an antenna element120with multiple adaptive load terminals is provided below in reference toFIG.12.FIG.12is a schematic showing a transmitting antenna element (unit cell) with a plurality of adaptive loads (which may be a part of an array of such antennas, as described above in reference toFIGS.3-8) of an RF charging pad, in accordance with some embodiments. In some embodiments, the RF charging pad1200includes one or more antenna elements1201(which may be any of the antenna elements as shown inFIGS.3B,4,6A-6E,7A-7D, and8). Each antenna element1201is powered/fed by a respective power amplifier (PA) switch circuit1208(which may be a respective one of the PA switch circuits103ofFIG.3A) that may be connected to a respective power amplifier1208or a source of power at a first end of the antenna element1201. In some embodiments, the input circuit that includes the power amplifier1208may additionally include a device that can change frequencies of the input signal or a device that can operate at multiple frequencies at the same time, such as an oscillator or a frequency modulator. In some embodiments, each antenna element1201of the RF charging pad1200includes a plurality of respective adaptive load terminals1202, for example,1202a,1202b,1202c, . . .1202n, at a plurality of positions within a respective antenna element1201. In some embodiments, the antenna element1201includes a conductive line forming a meandered line pattern (as discussed above in reference toFIGS.3,4, and6-8). In some embodiments, each adaptive load terminals of the plurality of adaptive load terminals1202for the antenna element1201is located at different positions on the conductive meandered line of the antenna element1201as shown inFIG.12. In some embodiments, a meandered line antenna element1201includes a conductive line with multiple turns in one plane. In some embodiments, the multiple turns may be square turns as shown for the antenna element1201inFIG.12. In some embodiments, the multiple turns may be round-edged turns. The conductive line may also have segments of varying widths, for example, a segment1206having a first width, and short-length segment1207that has a second width that is less than the first width. In some embodiments, at least one of the adaptive load terminals1202ais positioned at one of the short-length segments (e.g., short-length segment1207) and another adaptive load terminal is positioned anywhere at one of the segments1206having the first width. In some embodiments, at least one of the adaptive load terminals1202is positioned or connected anywhere on a width segment, for example, at the middle of a width segment of the meandered line antenna element1201. In some embodiments, the last adaptive load terminal1202nis positioned at a second end of the conductive line (opposite to a first end at the input terminal1203of the antenna element1201described above in reference toFIGS.3,4, and6-8). In some embodiments, in certain design and optimization, an adaptive load terminal is not necessarily positioned at a second end of the meandered line antenna element1201but can be positioned at any location of the antenna element1201. In some embodiments, the RF charging pad1200also includes (or is in communication with) a central processing unit1210(also referred to here as processor1210). In some embodiments, the processor1210is configured to control RF signal frequencies and to control impedance values at each of the adaptive load terminals1202, e.g., by communicating with a plurality of the load picks or adaptive loads1212, for example,1212a,1212b,1212c, . . .1212n, for each of the adaptive load terminals1202(as discussed above in reference to load pick or adaptive load106inFIGS.3A and3B). In some embodiments, an electronic device (e.g., a device that includes a receiver1204as an internally or externally connected component, such as a remote that is placed on top of a charging pad1200that may be integrated within a housing of a streaming media device or a projector) and uses energy transferred from one or more RF antenna elements1201of the charging pad1200to the receiver1204to charge a battery and/or to directly power the electronic device. In some embodiments, the adaptive load terminals1202at a particular zone or selected positions of the antenna element1201(e.g., a zone on the antenna element1201located underneath a position at which an electronic device (with an internally or externally connected RF receiver1204) to be charged is placed on the charging pad) are optimized in order to maximize power received by the receiver1204. For example, the CPU1210upon receiving an indication that an electronic device with an internally or externally connected RF receiver1204has been placed on the pad1200in a particular zone on the antenna element1201may adapt the plurality of adaptive loads1212, for example, adaptive loads1212a,1212b,1212c, . . .1212n, that are respectively coupled to the adaptive terminals1202, in order to maximize power transferred to the RF receiver1204. Adapting the set of adaptive loads1212may include the CPU1210commanding one or more of the adaptive loads to try various impedance values for one or more of the adaptive load terminals1202that are coupled to different positions of the antenna element1201. Additional details regarding adapting adaptive loads were provided above, and, for the sake of brevity, are not repeated here. The effective impedance value (Zeffective) at a particular position/portion of the conductive line of the antenna element1201is affected by a number of variables and may be manipulated by adjusting configurations of the adaptive load terminals1212that are coupled to various positions on the antenna element1201. In some embodiments, an effective impedance value (Zeffective), starting from a point that divides sections1225(which starts at the terminal1203of the antenna element1201and extends to an edge of the receiver1204) and1227(which is formed by the rest of the transmitting antenna element1201and the terminal1202n) and ending at the TX antenna1201's connection to the adaptive load1212n(e.g., terminal1202n) will change based on location of the receiver1204on the TX antenna1201and based on a set of selected loads provided by adaptive loads1212at various positions within section1227. In some embodiments, the selected loads are optimized by the adaptive loads1212(in conjunction with the processor1210) to tune Zeffectivein such a way that the energy transferred between terminal1203and the receiver1204reaches a maximum (e.g., 75% or more of energy transmitted by antenna elements of the pad1200is received by the RF receiver1204, such as 98%), while energy transfer may also stay at a minimum from terminal1203to terminal1202n(e.g., less than 25% of energy transmitted by antenna elements of the pad1200is not received by the RF receiver1204and ends up reaching terminals positioned within section1227or ends up being reflected back, including as little as 2%). In some embodiments, a selected several adaptive loads1212of the plurality of adaptive loads1212are used (by the processor1210) on the antenna element1201to adjust the impedance and/or frequency of the antenna element1201. In one example, with reference toFIG.12, only adaptive load terminals1202aand1202care connected at a particular point in time to adaptive loads1212aand1212crespectively, while adaptive load terminals1202band1202nare disconnected at the particular point in time. In another example, with reference toFIG.12, only adaptive load terminals1202aand1202nare connected at a particular point in time to adaptive loads1212aand1212n, respectively, while adaptive load terminals1202band1202care disconnected at the particular point in time. In some embodiments, all of the adaptive load terminals1202are connected at a particular point in time to their respective adaptive loads1212. In some embodiments, none of the adaptive load terminals1202are connected at a particular point in time to their respective adaptive loads1212. In some embodiments, the impedance value of each of the adaptive loads1212connected to a selected adaptive load terminal1212is adjusted individually to optimize the energy transfer. In embodiments in which a meandered line antenna has been optimized for the multi-band operation, the multiple adaptive load configuration within a single antenna element also enables a broader frequency band adjustment compared with a single adaptive load configuration within a single antenna element as described inFIG.3Babove. The multiple adaptive load configuration within a single antenna element further enhances multiple frequency band operation on a single antenna element. For example, a single antenna element1201with multiple adaptive load terminals is capable of operating at a wider frequency band than a corresponding antenna element that is configured with one adaptive load terminal. In some embodiments, adapting the set of adaptive loads1212also or alternatively includes the CPU1210causing the set of antenna elements to transmit RF signals at various frequencies until a frequency is found at which a maximum amount of energy is transferred to the RF receiver1204. In some embodiments, for example, one of the antenna elements transmits RF signals at a first frequency, and another one of the antenna elements transmits RF signals at a second frequency that is different from the first frequency. In some embodiments, adjusting the impedance value and/or the frequencies at which the set of antenna elements transmits causes changes to the amount of energy transferred to the RF receiver1204. In this way, the amount of energy transferred to the RF receiver1204that is maximized (e.g., to transfer at least 75% of the energy transmitted by antenna elements of the pad1200to the receiver1204, and in some embodiments, adjusting the impedance value and/frequencies may allow up to 98% of the energy transmitted to be received by the receiver1204) may be received at any particular point on the pad1200at which the RF receiver1204might be placed. In some embodiments, the CPU1210determines that a maximum amount of energy is being transferred to the RF receiver1204when the amount of energy transferred to the RF receiver1204crosses a predetermined threshold (e.g., 75% or more of transmitted energy is received, such as up to 98%) or by testing transmissions with a number of impedance and/or frequency values and then selecting the combination of impedance and frequency that results in maximum energy being transferred to the RF receiver1204(also as described in reference to the adaptation scheme inFIGS.3A-3Dabove). In some embodiments, processor1210is connected to the receiver1204through a feedback loop (e.g. by exchanging messages using a wireless communication protocol, such as BLUETOOTH low energy (BLE), WIFI, ZIGBEE, infrared beam, near-field transmission, etc, to exchange messages). In some embodiments, the adaptation scheme is employed to test various combinations of impedance values of the adaptive impedance loads1212and RF frequencies, in order to maximize energy transferred to an RF receiver1204. In such embodiments, each of the adaptive load1212is configured to adjust the impedance value along a range of values, such as between 0 and infinity. In some embodiments, the adaptation scheme is employed when one or more RF receivers are placed on top of one of the antenna element1201. In some embodiments, an adaptation scheme is employed to adaptively adjust the impedance values and/or frequencies of the RF signal(s) emitted from the RF antenna(s)1201of the charging pad1200, in order to determine which combinations of frequency and impedance result in maximum energy transfer to the RF receiver1204. For example, the processor1210that is connected to the charging pad1200tries different frequencies (i.e., in the allowed operating frequency range or ranges) by using different selected sets of adaptive loads1212at different locations of the antenna element1201, e.g. enabling or disabling certain adaptive loads1212, to attempt to adaptively optimize for better performance. For example, a simple optimization either opens/disconnects or closes/shorts each load terminal to ground (in embodiments in which a relay is used to switch between these states), and may also cause RF antenna element1201to transmit at various frequencies. In some embodiments, for each combination of relay state (open or shorted) and frequency, the energy transferred to the receiver1204is monitored and compared to energy transferred when using other combinations. The combination that results in maximum energy transfer to the receiver1204is selected and used to continue to transmitting the one or more RF signals using one or more antenna elements1201to the receiver1204. In some embodiments, the single antenna element1201with multiple adaptive loads1212of the pad1200may be configured to operate in two or more distinct frequency bands (such as the ISM bands described above), e.g., a first frequency band with a center frequency of 915 MHz and a second frequency band with a center frequency of 5.8 GHz. In these embodiments, employing the adaptation scheme may include transmitting RF signals and then adjusting the frequency at first predetermined increments until a first threshold value is reached for the first frequency band and then adjusting the frequency at second predetermined increments (which may or may not be the same as the first predetermined increments) until a second threshold value is reached for the second frequency band. In some embodiments, a single antenna element can operate at multiple different frequencies within one or more frequency bands. For example, the single antenna element1201may be configured to transmit at 902 MHz, 915 MHz, 928 MHZ (in the first frequency band) and then at 5.795 GHz, 5.8 GHz, and 5.805 GHz (in the second frequency band). The single antenna element1201can operate at more than one frequency bands as a multi-band antenna. A transmitter with at least one antenna element1201can be used as a multi-band transmitter. In some embodiments, multiple antenna elements1201each with multiple adaptive loads1212may be configured within a particular transmission pad to allow the particular transmission pad to operate in two or more distinct frequency bands respectively at the same time. For example, a first antenna element1201of the particular transmission pad operates at a first frequency or frequency band, a second antenna element1201of the particular transmission pad operates at a second frequency or frequency band, and a third antenna element1201of the particular transmission pad operates at a third frequency or frequency band, and a fourth antenna element1201of the particular transmission pad operates at a fourth frequency or frequency band, and the four frequency bands are distinct from each other. In this way, the particular transmission pad is configured to operate at multiple different frequency bands. In some embodiments, the transmitter described herein can transmit wireless power in one frequency or frequency band, and transmit and exchange data with a receiver in another frequency or frequency band. Different antenna elements operating at different frequencies can maximize energy transfer efficiency when a smaller device is charged with higher frequencies and a larger device is charged with lower frequencies on the same charging pad. For example, devices that require a higher amount of power, such as mobile phones, may also have more space to include larger antennas, thus making a lower frequency of 900 MHz a suitable frequency band. As a comparison, a smaller device, such as an earbud, may require a small amount of power and may also have less space available for longer antennas, thus making a higher frequency of 2.4 or 5.8 GHz a suitable frequency band. This configuration enables more flexibility in the types and sizes of antennas that are included in receiving devices. Turning now toFIG.13, in accordance with some embodiments, a flow chart of a method1300of charging an electronic device through radio frequency (RF) power transmission by using at least one RF antenna with a plurality of adaptive loads is provided. Initially, a charging pad including a transmitter is provided in step1302that includes at least one RF antenna (e.g., antenna element1201, as described with respect toFIG.12above which further includesFIGS.3-8) for transmitting one or more RF signals or waves, i.e., an antenna designed to and capable of transmitting RF electromagnetic waves. In some embodiments, an array of RF antenna elements1201are arranged adjacent to one another in a single plane, in a stack, or in a combination of thereof, thus forming an RF charging pad1200(as described in reference toFIGS.6A-6E,7A-7D and8). In some embodiments, the RF antenna elements1201each include an antenna input terminal (e.g., the first terminal1203discussed above in reference toFIG.12) and a plurality of antenna output terminals (e.g., the plurality of adaptive load terminals1202discussed above in reference toFIG.12). In some embodiments, the antenna element1201includes a conductive line that forms a meandered line arrangement (as shown inFIGS.3-4, and6-12). The plurality of adaptive load terminals1202are positioned at different locations of the conductive line of the antenna element1201. In some embodiments, the transmitter further comprises a power amplifier electrically coupled between the power input and the antenna input terminal (e.g., PA1208inFIG.12). Some embodiments also include respective adaptive loads1212a,1212b,1212c, . . .1212nelectrically coupled to the plurality of antenna output terminals (e.g., adaptive load terminals1202inFIG.12). In some embodiments, the transmitter includes a power input configured to be electrically coupled to a power source, and at least one processor (e.g., processor1210inFIG.12, and processor110inFIGS.3A-3B) configured to control at least one electrical signal sent to the antenna. In some embodiments, the at least one processor is also configured to control the frequency and/or amplitude of the at least one signal sent to the antenna. In some embodiments, each RF antenna of the transmitter includes: a conductive line forming a meandered line pattern, a first terminal (e.g., terminal1203) at a first end of the conductive line for receiving current that flows through the conductive line at a frequency controlled by one or more processors, and a plurality of adaptive load terminals (e.g., terminals1202), distinct from the first terminal, at a plurality of positions of the conductive line, the plurality of adaptive load terminals coupled to a respective component (e.g., adaptive loads1212inFIG.12) controlled by the one or more processors and that allows for modifying an impedance value of the conductive line. In some embodiments, the conductive line is disposed on or within a first antenna layer of a multi-layered substrate. Also in some embodiments, a second antenna is disposed on or within a second antenna layer of the multi-layered substrate. Finally, some embodiments also provide a ground plane disposed on or within a ground plane layer of the multi-layered substrate. In some embodiments, a receiver (e.g., receiver1204in reference toFIG.12) is also provided (also as described in reference toFIG.3). The receiver also includes one or more RF antennas for receiving RF signals. In some embodiments, the receiver includes at least one rectenna that converts the one or more RF signals into usable power to charge a device that includes the receiver1204as an internally or externally connected component (see also steps504,506,510,514and518in reference toFIG.5). In use, the receiver1204is placed within a near-field radio frequency distance to the at least one antenna of the transmitter or the charging pad. For example, the receiver may be placed on top of the at least one RF antenna1201or on top of a surface that is adjacent to the at least one RF antenna1201, such as a surface of a charging pad1200. In step1304, one or more RF signals are then transmitted via at the least one RF antenna1201. The system is then monitored in step1306to determine the amount of energy that is transferred via the one or more RF signals from the at least one antenna1201to one or more RF receivers (as is also discussed above). In some embodiments, this monitoring1306occurs at the transmitter, while in other embodiments the monitoring1306occurs at the receiver which sends data back to the transmitter via a back channel (e.g., over a wireless data connection using WIFI or BLUETOOTH). In some embodiments, the transmitter and the receiver exchange messages via the back channel, and these messages may indicate energy transmitted and/or received, in order to inform the adjustments made at step1308. In some embodiments, in step1308, a characteristic of the transmitter is adaptively adjusted to attempt to optimize the amount of energy that is transferred from the at least one RF antenna1201to the receiver. In some embodiments, this characteristic is a frequency of the one or more RF signals and/or an impedance of the transmitter. In some embodiments, the impedance of the transmitter is the impedance of the adjustable loads. Also in some embodiments, the at least one processor is also configured to control the impedance of the selected set of the plurality of adaptive loads1212. Additional details and examples regarding impedance and frequency adjustments are provided above. In some embodiments, the at least one processor (e.g. CPU1210inFIG.12) dynamically adjusts the impedance of the adaptive load based on the monitored amount of energy that is transferred from the at least one antenna1201to the RF receiver. In some embodiments, the at least one processor simultaneously controls the frequency of the at least one signal sent to the antenna. In some embodiments, the single antenna element1201with multiple adaptive loads1212of the pad1200may be dynamically adjusted by the one or more processors to operate in two or more distinct frequency bands (such as the ISM bands described above) at the same time or at different times, e.g., a first frequency band with a center frequency of 915 MHz and a second frequency band with a center frequency of 5.8 GHz. In these embodiments, employing the adaptation scheme may include transmitting RF signals and then adjusting the frequency at first predetermined increments until a first threshold value is reached for the first frequency band and then adjusting the frequency at second predetermined increments (which may or may not be the same as the first predetermined increments) until a second threshold value is reached for the second frequency band. For example, the single antenna element1201may be configured to transmit at 902 MHz, 915 MHz, 928 MHZ (in the first frequency band) and then at 5.795 GHz, 5.8 GHz, and 5.805 GHz (in the second frequency band). The single antenna element1201can operate at more than one frequency bands as a multi-band antenna. A transmitter with at least one antenna element1201can be used as a multi-band transmitter. In some embodiments, a charging pad or transmitter may include one or more of the antenna element1201with a plurality of adaptive loads as described inFIG.12and one or more antenna element120with one adaptive load as described inFIG.3A-3D. FIGS.14A-14Dare schematics showing various configurations for individual antenna elements that can operate at multiple frequencies or frequency bands within an RF charging pad, in accordance with some embodiments. As shown inFIGS.14A-14D, an RF charging pad100(FIGS.3A-3B) or an RF charging pad1200(FIG.12) may include antenna elements120(FIG.3B) or1201(FIG.12) that configured to have conductive line elements that have varying physical dimensions. For example,FIGS.14A-14Dshow examples of structures for an antenna element that each include a conductive line formed into different meandered line patterns at different portions of the element. The conductive lines at different portions or positions of the element may have different geometric dimensions (such as widths, or lengths, or trace gauges, or patterns, spaces between each trace, etc.) relative to other conductive lines within an antenna element. In some embodiments, the meandered line patterns may be designed with variable lengths and/or widths at different locations of the pad (or an individual antenna element). These configurations of meandered line patterns allow for more degrees of freedom and, therefore, more complex antenna structures may be built that allow for wider operating bandwidths and/or coupling ranges of individual antenna elements and the RF charging pad. In some embodiments, the antennas elements120and1201described herein may have any of the shapes illustrated inFIGS.14A-14D. In some embodiments, each of the antenna elements shown inFIGS.14A-14Dhas an input terminal (123inFIG.1B or1203inFIG.12) at one end of the conductive line and at least one adaptive load terminals (121inFIG.1B or1202a-ninFIG.12) with adaptive loads (106inFIG.1B or1212a-ninFIG.12) as described above at another end or a plurality of positions of the conductive line. In some embodiments, each of the antenna elements shown inFIGS.14A-14Dcan operate at two or more different frequencies or two or more different frequency bands. For example, a single antenna element can operate at a first frequency band with a center frequency of 915 MHz at a first point in time and a second frequency band with a center frequency of 5.8 GHz at a second point in time, depending on which frequency is provided at an input terminal of each of the antenna elements. Moreover, the shapes of the meandered line patterns shown inFIGS.14A-14Dare optimized to allow the antenna elements to operate efficiently at multiple different frequencies. In some embodiments, each of the antenna elements shown inFIGS.14A-14Dcan operate at two or more different frequencies or two or more different frequency bands at the same time when the input terminal is supplied with more than two distinct frequencies that can be superimposed. For example, a single antenna element can operate at a first frequency band with a center frequency of 915 MHz and a second frequency band with a center frequency of 5.8 GHz at the same time when both frequency bands with a first center frequency of 915 MHz and a second center frequency of 5.8 GHz are supplied at the input terminal of the conductive line. In yet another example, a single antenna element can operate at multiple different frequencies within one or more frequency bands. In some embodiments, the operating frequencies of the antenna elements can be adaptively adjusted by one or more processors (110inFIGS.3A-3B or1210inFIG.12) as described above according to the receiver antenna dimension, frequency, or the receiver loads and the adaptive loads on the charging pad. In some embodiments, each of the antenna elements shown inFIGS.14A-14Dwith different meandered patterns at different portions of the conductive line can operate more efficiently at multiple frequencies compared with the more symmetrical meandered line structures (For example,FIG.3B,4,6A-6B, or8). For example, energy transfer efficiency at different operating frequencies of the antenna elements shown inFIGS.14A-14Dwith different meandered patterns at different portions of the conductive line can be improved by about at least 5%, and in some instance at least 60%, more than the more symmetrical meandered line structure elements. For example, the more symmetrical meandered line structure antenna element may be able to transfer no more than 60% of transmitted energy to a receiving device while operating at a new frequency other than a frequency for which the more symmetrical meandered line structure antenna element has been designed (e.g., if the more symmetrical meandered line structure antenna element is designed to operate at 900 MHz, if it then transmits a signal having a frequency of 5.8 GHz it may only be able to achieve an energy transfer efficiency of 60%). In contrast, the antenna element with different meandered patterns (e.g., those shown inFIGS.14A-14D) may be able to achieve an energy transfer efficiency of 80% or more while operating at various frequencies. In this way, the designs for antenna elements shown inFIGS.14A-14Densure that a single antenna element is able to achieve a more efficient operation at various different frequencies. FIG.15is schematic showing an example configuration for an individual antenna element that can operate at multiple frequencies or frequency bands by adjusting the length of the antenna element, in accordance with some embodiments. In some embodiments as shown inFIG.15, at least one transmitting antenna element1502(as described inFIGS.3-8and13-14) of the one or more transmitting antenna elements of an RF charging pad1500has a first conductive segment1504(a first portion of a meandered conductive line, such as any of those described above for antenna elements120and1201) and a second conductive segment1506(a second portion of the meandered conductive line, such as any of those described above for antenna elements120and1201). In some embodiments, the first conductive segment includes an input terminal (123inFIG.3B or1203inFIG.12). In some embodiments, the at least one transmitting antenna element1502is configured to operate at a first frequency (e.g., 2.4 GHz) while the first conductive segment1504is not coupled with the second conductive segment1506. In some embodiments, the at least one transmitting antenna element1502is configured to operate at a second frequency (e.g., 900 MHz) which is different from the first frequency while the first conductive segment is coupled with the second conductive segment. In some embodiments, one or more processors (110inFIGS.3A-3B or1210inFIG.12) are configured to cause coupling of the first segment with the second segment in conjunction with instructing a feeding element (as described as108inFIGS.3A-3B and1208inFIG.12) to generate current with a second frequency (e.g., 900 MHz) that is distinct from the first frequency (e.g., 2.4 GHz), thereby allowing the antenna element1502to more efficiently operate at the second frequency. The one or more processor may also be configured to cause de-coupling of the second conductive segment from the first conductive segment in conjunction with instructing the feeding element to generate current with the first frequency instead of the second frequency, thereby allowing the antenna element1502to more efficiently operate at the first frequency again. In some embodiments, the one or more processors are configured to determine whether to causing the coupling (or de-coupling) of these conductive segments based on information received from a receiver (e.g., RX104or1204) that identifies a frequency at which the receiver is configured to operate (e.g., for larger devices with longer receiving antennas, this frequency may be 900 MHz, while for smaller devices with small receiving antennas, this frequency may be 2.4 GHz). [In some embodiments, the coupling described here inFIG.15can be implemented by directly connecting two different segments of a single antenna element1502while bypassing the conductive line located in-between the two connection points or the two different segments. In some embodiments, coupling can be implemented between more than two different segments of the antenna element1502. The coupling of the different portions or segments of a single meandered line antenna element1502can effectively change the size or length of the conductive line of the antenna element1502, and therefore enable the single antenna element1502to operate at different frequencies. The single antenna element1502may also operate at more than one frequency bands as a multi-band antenna. FIG.16Ashows a top perspective view of a schematic drawing of an exemplary near-field power transfer system1600.FIG.16Bshows a bottom perspective view of a schematic drawing of an exemplary near-field power transfer system1600. The power transfer system1600may comprise a top surface1601, a bottom surface1602, and sidewalls1603. In some embodiments, a housing containing components of the power transfer system1600may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface1601may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls1603may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. The power transfer system1600may radiate RF energy and thus transfer power when the power transfer system1600is adjacent to a second power transfer system (not shown). As such, a power transfer system1600may be on a “transmit side,” so as to function as a power transmitter, or the power transfer system1600may be on a “receive side,” so as to function as a power receiver. In some embodiments, where the power transfer system1600is associated with a transmitter, the power transfer system1600(or subcomponents of the power transfer system1600) may be integrated into the transmitter device, or may be externally wired to the transmitter. Likewise, in some embodiments, where the power transfer system1600is associated with a receiver, the power transfer system1600(or subcomponents of the power transfer system1600) may be integrated into the receiver device, or may be externally wired to the receiver. A substrate1607may be disposed within a space defined between the top surface1601, sidewalls1603, and the bottom surface1602. In some embodiments, the power transfer system1600may not include a housing and the substrate1607may include the top surface1601, sidewalls1603, and the bottom surface1602. The substrate1607may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may generate radiation, and may act as thin reflectors. An antenna1604may be constructed on or below the top surface1601. When the power transfer system1600is associated with a power transmitter, the antenna1604may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system1600is associated with a power receiver, the antenna1604may be used for receiving electromagnetic waves. In some embodiments, the power transfer system1600may operate as a transceiver and the antenna1604may both transmit and receive electromagnetic waves. The antenna1604may be constructed from materials such as metals, alloys, metamaterials and composites. For example, the antenna1604may be made of copper or copper alloys. The antenna1604may be constructed to have different shapes based on the power transfer requirements. In the exemplary system1600shown inFIG.16AandFIG.16B, the antenna1604is constructed in a shape of a spiral including antenna segments1610that are disposed close to each other. The currents flowing through the antenna segments1610may be in opposite directions. For example, if the current in the antenna segment1610bis flowing from left to right ofFIG.16A, the current each of the antenna segments1610a,1610cmay be flowing from right to left. The opposite flow of the current results in mutual cancellation of the electromagnetic radiation the far field of the power transfer system1600. In other words, the far field electromagnetic radiation generated by one or more antenna segments1610left of an imaginary line1615is cancelled out by the far field electromagnetic radiation generated by one or more antenna segments1610right of the line1615. Therefore, there may be no leakage of power in the far field of the power transfer system1600. Such cancellation, however, may not occur in a near-field active zone of the power transfer system1600, where the transfer of power may occur. The power transfer system1600may include a ground plane1606at or above the bottom surface1602. The ground plane1606may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane1606may be formed by copper or a copper alloy. In some embodiments, the ground plane1606may be constructed of a solid sheet of material. In other embodiments, the ground plane1606may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. A via1605carrying a power feed line (not shown) to the antenna may pass through the ground plane1606. The power feed line may supply current to the antenna1604. In some embodiments, the ground plane1606may be electrically connected to the antenna1604. In some embodiments, the ground plane1606may not be electrically connected to the antenna1604. For such implementations, an insulation area1608to insulate the via1605from the ground plane1606may be constructed between the via1605and the ground plane1606. In some embodiments, the ground plane1606may act as a reflector of the electromagnetic waves generated by the antenna1604. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system1600by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna1604from or towards the top surface1601. Therefore, there may be no leakage of electromagnetic power from the bottom surface1602. Therefore, as a result of the antenna1604and the ground plane1606, the electromagnetic waves transmitted or received by the power transfer system1600accumulate in the near field of the system1600. The leakage to the far field of the system1600is minimized. FIG.17Aschematically illustrates a top perspective view of an exemplary near-field power transfer system1700, according to an embodiment of the disclosure. In some embodiments, the power transfer system1700may be a part of or associated with a power transmitter. In other embodiments, the power transfer system1700may be a part of or associated with a power receiver. The power transfer system1700may comprise a housing defined by a top surface1701, a bottom surface (not shown), and sidewalls1703. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface1701may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls1703may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate1707may be disposed within a space defined between the top surface1701, sidewalls1703, and the bottom surface1702. In some embodiments, the power transfer system1700may not include a housing and the substrate1707may include the top surface1701, sidewalls1703, and the bottom surface1702. The substrate1707may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may generate radiation, and may act as thin reflectors. An antenna1704may be constructed on or below the top surface1701. When the power transfer system1700is a part of or associated with a power transmitter, the antenna1704may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system1700is a part of or associated with a power receiver, the antenna1704may be used for receiving electromagnetic waves. In some embodiments, the power transfer system1700may operate as a transceiver and the antenna1704may both transmit and receive electromagnetic waves. The antenna1704may be constructed from materials such as metals, alloys, metamaterials, and composites. For example, the antenna1704may be made of copper or copper alloys. The antenna1704may be constructed to have different shapes based on the power transfer requirements. In the exemplary system1700shown inFIG.17Athe antenna1704is constructed in a shape of a spiral including antenna segments which are disposed close to each other. A signal feed line (not shown) may be connected to the antenna1704through a via1705. FIG.17Bschematically illustrates a side view of the exemplary power transmission system1700. As shown, an upper metal layer may form the antenna1704, and a lower metal layer may form the ground plane1706. The substrate1707may be disposed in between the upper and lower metal layer. The substrate1707may include materials such as FR4, metamaterials, or any other materials known in the art. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may have to be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or generate radiation, and may act as thin reflectors. FIG.17Cschematically illustrates a top perspective view of antenna1704. The antenna1704comprises a connection point1709for a feed line (not shown) coming through the via1705.FIG.17Dschematically illustrates a side perspective view of the ground plane1706. In an embodiment, the ground plane1706comprises a solid metal layer. In other embodiments, the ground plane1706may include structures such as stripes, meshes, and lattices and may not be completely solid. The ground plane1706may also comprise a socket1709for the via1705to pass through. Around the socket1709, the ground plane1706may also include an insulating region1710to insulate the socket1709from the rest of the ground plane1706. In some embodiments, the ground plane may have an electrical connection to a line coming through the via, and the insulating region1710may not be required. FIG.18schematically illustrates a top perspective view of an exemplary near-field power transfer system1800, according to an embodiment of the disclosure. In some embodiments, the power transfer system1800may be a part of or associated with a power transmitter. In other embodiments, the power transfer system1800may be a part of or associated with a power receiver. The power transfer system1800may comprise a housing defined by a top surface1801, a bottom surface (not shown), and sidewalls1803. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface1801may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls1803may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate1807may be disposed within a space defined between the top surface1801, sidewalls1803, and the bottom surface1802. In some embodiments, the power transfer system1800may not include a housing and the substrate1807may include the top surface1801, sidewalls1803, and the bottom surface1802. The substrate1807may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may transmit radiation, and may act as thinreflectors. An antenna1804may be constructed on or below the top surface. When the power transfer system1800is a part of or associated with a power transmitter, the antenna1804may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system1800is a part of or associated with a power receiver, the antenna1804may be used for receiving electromagnetic waves. In some embodiments, the power transfer system1800may operate as a transceiver and the antenna1804may both transmit and receive electromagnetic waves. The antenna1804may be constructed from materials such as metals, alloys, metamaterials and composites. For example, the antenna1804may be made of copper or copper alloys. The antenna1804may be constructed to have different shapes based on the power transfer requirements. In the exemplary system1800shown inFIG.18, the antenna1804is constructed in a shape of a dipole including a first meandered pole1809aand a second meandered pole1809b. A first power feed line (not shown) to the first meandered pole1809amay be carried by a first via1805aand a second power feed line (not shown) to the second meandered pole1809bmay be carried by a second via1805b. The first power feed line may supply current to the first meandered pole1809aand the second power feed line may supply current to the second meandered pole1809b. The first meandered pole1809aincludes antenna segments1810which are disposed close to each other and the second meandered pole1809bincludes antenna segments1811also disposed close to each other. The currents flowing through the neighboring antenna segments1810,1811may be in opposite directions. For example, if the current in an antenna segment1810bis flowing from left to right ofFIG.18, the current in each of the antenna segments1810a,1810cmay be flowing from right to left. The opposite flow of the current across any number of antenna segments1810of the power transfer system1800results in mutual cancellation of the far field electromagnetic radiation generated by the power transfer system1800. Additionally or alternatively, the far field electromagnetic radiation generated by the antenna segments1810of the first pole1809amay be cancelled by the electromagnetic radiation generated by antenna segments1811of the second pole1809b. It should be appreciated that the far field cancellation may occur across any number of segments1810,1811and/or across any number of poles1809. Therefore, there may be no leakage of power in the far field of the power transfer system1800. Such cancellation, however, may not occur in a near-field active zone of the power transfer system1800, where the transfer of power may occur. The power transfer system1800may include a ground plane (not shown) at or above the bottom surface. The ground plane may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane may be formed by copper or a copper alloy. In some embodiments, the ground plane may be constructed of a solid sheet of material. In other embodiments, the ground plane may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The vias1805carrying the power feed lines to the antenna may pass through the ground plane. In some embodiments, the ground plane may be electrically connected to the antenna. In some embodiments, the ground plane may not be electrically connected to the antenna1804. For such implementations, an insulation area to insulate the vias1805from the ground plane may be constructed between the vias1805and the ground plane. In some embodiments, the ground plane may act as a reflector of the electromagnetic waves generated by the antenna1804. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system1800by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna1804from or towards the top surface1801. Therefore, there may be no leakage of electromagnetic power from the bottom surface. FIG.19schematically illustrates a top perspective view of an exemplary near-field power transfer system1900, according to an embodiment of the disclosure. In some embodiments, the power transfer system1900may be a part of or associated with a power transmitter. In other embodiments, the power transfer system1900may be a part of or associated with a power receiver. The power transfer system1900may comprise a housing defined by a top surface1901, a bottom surface (not shown), and sidewalls1903. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface1901may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls1903may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate1907may be disposed within a space defined between the top surface1901, sidewalls1903, and the bottom surface1902. In some embodiments, the power transfer system1900may not include a housing and the substrate1907may include the top surface1901, sidewalls1903, and the bottom surface1902. The substrate1907may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may generate radiation, and may act as thinreflectors. An antenna1904may be constructed on or below the top surface1901. When the power transfer system1900is a part of or associated with a power transmitter, the antenna1904may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system1900is a part of or associated with a power receiver, the antenna1904may be used for receiving electromagnetic waves. In some embodiments, the power transfer system1900may operate as a transceiver and the antenna1904may both transmit and receive electromagnetic waves. The antenna1904may be constructed from materials such as metals, alloys, and composites. For example, the antenna1904may be made of copper or copper alloys. The antenna1904may be constructed to have different shapes based on the power transfer requirements. In the exemplary system1900shown inFIG.19, the antenna1904is constructed in a shape of a loop including loop segments1910which are disposed close to each other. The currents flowing through the neighboring loop segments1910may be in opposite directions. For example, if the current in a first loop segment1910ais flowing from left to right ofFIG.19, the current in a second loop segment1910bmay be flowing from right to left. The opposite flow of the current results in mutual cancellation of the electromagnetic radiation the far field of the power transfer system1900. Therefore, there may be no leakage of power in the far field of the power transfer system1900. Such cancellation, however, may not occur in a near-field active zone of the power transfer system1900, where the transfer of power may occur. The power transfer system1900may include a ground plane (not shown) at or above the bottom surface. The ground plane may be formed by materials such as metal, alloys, metamaterials, and composites. In an embodiment, the ground plane may be formed by copper or a copper alloy. In some embodiments, the ground plane may be constructed of a solid sheet of material. In other embodiments, the ground plane may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The vias1905carrying the power feed lines (not shown) to the antenna may pass through the ground plane. The power feed lines may provide current to the antenna1904. In some embodiments, the ground plane106may be electrically connected to the antenna. In some embodiments, the ground plane may not be electrically connected to the antenna1904. For such implementations, an insulation area to insulate the vias1905from the ground plane may be constructed between the vias305and the ground plane. In some embodiments, the ground plane may act as a reflector of the electromagnetic waves generated by the antenna1904. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system300by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna1904from or towards the top surface1901. Therefore, there may be no leakage of electromagnetic power from the bottom surface. FIG.20schematically illustrates a top perspective view of an exemplary near-field power transfer system2000, according to an embodiment of the disclosure. In some embodiments, the power transfer system2000may be a part of or associated with a power transmitter. In other embodiments, the power transfer system2000may be a part of or associated with a power receiver. In other embodiments, the power transfer system2000may be a part of or associated with a transceiver. The power transfer system2000may comprise a housing defined by a top surface2001, a bottom surface (not shown), and sidewalls2003. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface2001may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls2003may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate2007may be disposed within a space defined between the top surface2001, sidewalls2003, and the bottom surface2002. In some embodiments, the power transfer system2000may not include a housing and the substrate2007may include the top surface2001, sidewalls2003, and the bottom surface2002. The substrate2007may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting cmTent, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may transmit radiation, and may act as thinreflectors. An antenna2004may be constructed on or below the top surface2001. When the power transfer system2000is a part of or associated with a power transmitter, the antenna2004may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system2000is a part of or associated with a power receiver, the antenna2004may be used for receiving electromagnetic waves. In some embodiments, the power transfer system2000may operate as a transceiver and the antenna2004may both transmit and receive electromagnetic waves. The power feed lines (not shown) to the antenna2004may be carried by the vias2005. The power feed lines may provide current to the antenna2004. The antenna2004may be constructed from materials such as metals, alloys, metamaterials, and composites. For example, the antenna2004may be made of copper or copper alloys. The antenna2004may be constructed to have different shapes based on the power transfer requirements. In the exemplary system2000shown inFIG.20, the antenna2004is constructed in a shape of concentric loops including antenna segments2010which are disposed close to each other. As shown inFIG.20, a single concentric loop may include two of the antenna segments2010. For example, the innermost loop may include a first antenna segment2010cto the right of an imaginary line2012roughly dividing the loops into two halves, and a corresponding second antenna segment2010c′ to the left of the imaginary line2012. The currents flowing through the neighboring antenna segments2010may be in opposite directions. For example, if the current in the antenna segments2010a′,2010b′,2010c′ is flowing from left to right ofFIG.20, the current in each of the antenna segments2010a,2010b,2010cmay be flowing from right to left. The opposite flow of the current results in mutual cancellation of the electromagnetic radiation at the far field of the power transfer system2000. Therefore, there may be no transfer of power to the far field of the power transfer system2000. Such cancellation, however, may not occur in a near-field active zone of the power transfer system2000, where the transfer of power may occur. One ordinarily skilled in the art will appreciate the cancellation of electromagnetic radiation in the far field and absence of such cancellation in the near-field is dictated by one or more solutions of Maxwell's equations for time-varying electric and magnetic fields generated by the currents flowing in opposite directions. One ordinarily skilled in the art should further appreciate the near field active zone is defined by the presence of electromagnetic power in the immediate vicinity of the power transfer system2000. The power transfer system2000may include a ground plane (not shown) at or above the bottom surface. The ground plane may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane may be formed by copper or a copper alloy. In some embodiments, the ground plane may be constructed of a solid sheet of material. In other embodiments, the ground plane may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The vias2005carrying the power feed lines to the antenna may pass through the ground plane. In some embodiments, the ground plane may be electrically connected to the antenna. In some embodiments, the ground plane may not be electrically connected to the antenna2004. For such implementations, an insulation area to insulate the vias2005from the ground plane may be constructed between the vias2005and the ground plane. In some embodiments, the ground plane may act as a reflector of the electromagnetic waves generated by the antenna2004. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system2000by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna2004from or towards the top surface2001. Therefore, there may be no leakage of electromagnetic power from the bottom surface. FIG.21schematically illustrates a top perspective view of an exemplary near-field power transfer system2100, according to an embodiment of the disclosure. In some embodiments, the power transfer system2100may be a part of or associated with a power transmitter. In other embodiments, the power transfer system2100may be a part of or associated with a power receiver. The power transfer system2100may comprise a housing defined by a top surface2101, a bottom surface (not shown), and sidewalls2103. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface2101may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls2103may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate2107may be disposed within a space defined between the top surface2101, sidewalls2103, and the bottom surface2102. In some embodiments, the power transfer system2100may not include a housing and the substrate2107may include the top surface2101, sidewalls2103, and the bottom surface2102. The substrate2107may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may transmit radiation, and may act as thin reflectors. An antenna2104may be constructed on or below the top surface2101. When the power transfer system2100is a part of or associated with a power transmitter, the antenna2104may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system2100is a part of or associated with a power receiver, the antenna2104may be used for receiving electromagnetic waves. In some embodiments, the power transfer system2100may operate as a transceiver and the antenna2104may both transmit and receive electromagnetic waves. The antenna2104may be constructed from materials such as metals, alloys, and composites. For example, the antenna2104may be made of copper or copper alloys. The antenna2104may be constructed to have different shapes based on the power transfer requirements. In the exemplary system2100shown inFIG.21, the antenna2104is constructed in a shape of a monopole. A via2105may carry a power feed line (not shown) to the antenna2104. The power feed line may provide current to the antenna2104. The power transfer system2100may include a ground plane (not shown) at or above the bottom surface. The ground plane may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane may be formed by copper or a copper alloy. In some embodiments, the ground plane may be constructed of a solid sheet of material. In other embodiments, the ground plane may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The via2105carrying the power feed line to the antenna2104may pass through the ground plane. In some embodiments, the ground plane may be electrically connected to the antenna. In some embodiments, the ground plane may not be electrically connected to the antenna2104. For such implementations, an insulation area to insulate the via2105from the ground plane may be constructed between the via2105and the ground plane. In some embodiments, the ground plane may act as a reflector of the electromagnetic waves generated by the antenna2104. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system2100by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna2104from or towards the top surface2101. Therefore, there may be no leakage of electromagnetic power from the bottom surface. FIG.22schematically illustrates a top perspective view of an exemplary near-field power transfer system2200, according to an embodiment of the disclosure. In some embodiments, the power transfer system2200may be a part of or associated with a power transmitter. In other embodiments, the power transfer system2200may be a part of or associated with a power receiver. The power transfer system2200may comprise a housing defined by a top surface2201, a bottom surface (not shown), and sidewalls2203. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface2201may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls2203may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate2207may be disposed within a space defined between the top surface2201, sidewalls2203, and the bottom surface2202. In some embodiments, the power transfer system2200may not include a housing and the substrate2207may include the top surface2201, sidewalls2203, and the bottom surface2202. The substrate2207may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may transmit radiation, and may act as thin reflectors. An antenna2204may be constructed on or below the top surface2201. When the power transfer system2200is a part of or associated with a power transmitter, the antenna2204may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system2200is a part of or associated with a power receiver, the antenna2204may be used for receiving electromagnetic waves. In some embodiments, the power transfer system2200may operate as a transceiver and the antenna2204may both transmit and receive electromagnetic waves. The antenna2204may be constructed from materials such as metals, alloys, and composites. For example, the antenna2204may be made of copper or copper alloys. A via2205may carry a power feed line (not shown) to the antenna. The power feed line may provide current to the antenna2204. The antenna2204may be constructed to have different shapes based on the power transfer requirements. In the exemplary system2200shown inFIG.22, the antenna2204is constructed in a shape of a monopole including antenna segments2210placed close to each other. The currents flowing through the neighboring antenna segments2210may be in opposite directions. For example, if the current in the antenna segment2210bis flowing from left to right ofFIG.22, the current each of the antenna segments2210a,2210cmay be flowing from right to left. The opposite flow of the current results in mutual cancellation of the electromagnetic radiation in the far field of the power transfer system2200. Therefore, there may be no transfer of power in the far field of the power transfer system2200. Such cancellation, however, may not occur in a near-field active zone of the power transfer system2200, where the transfer of power may occur. One ordinarily skilled in the art will appreciate the cancellation of electromagnetic radiation in the far field and absence of such cancellation in the near-field is dictated by one or more solutions of Maxwell's equations for time-varying electric and magnetic fields generated by the currents flowing in opposite directions. One ordinarily skilled in the art should further appreciate the near field active zone is defined by the presence of electromagnetic power in the immediate vicinity of the power transfer system2200. The power transfer system2200may include a ground plane (not shown) at or above the bottom surface. The ground plane may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane may be formed by copper or a copper alloy. In some embodiments, the ground plane may be constructed of a solid sheet of material. In other embodiments, the ground plane may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The via2205carrying the power feed line to the antenna2204may pass through the ground plane. In some embodiments, the ground plane may be electrically connected to the antenna. In some embodiments, the ground plane may not be electrically connected to the antenna2204. For such implementations, an insulation area to insulate the via2205from the ground plane may be constructed between the via2205and the ground plane. In some embodiments, the ground plane may act as a reflector of the electromagnetic waves generated by the antenna2204. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system2200by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna2204from or towards the top surface2201. Therefore, there may be no leakage of electromagnetic power from the bottom surface. FIG.23schematically illustrates a top perspective view of an exemplary near-field power transfer system2300, according to an embodiment of the disclosure. In some embodiments, the power transfer system2300may be a part of or associated with a power transmitter. In other embodiments, the power transfer system2300may be a part of or associated with a power receiver. The power transfer system2300may comprise a housing defined by a top surface2301, a bottom surface (not shown), and sidewalls2303. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface2301may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls2303may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate2307may be disposed within a space defined between the top surface2301, sidewalls2303, and the bottom surface2302. In some embodiments, the power transfer system2300may not include a housing and the substrate2307may include the top surface2301, sidewalls2303, and the bottom surface2302. The substrate2307may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may transmit radiation, and may act as thin reflectors. An antenna2304may be constructed on or below the top surface2301. When the power transfer system2300is a part of or associated with a power transmitter, the antenna2304may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system2300is a part of or associated with a power receiver, the antenna2304may be used for receiving electromagnetic waves. In some embodiments, the power transfer system2300may operate as a transceiver and the antenna2304may both transmit and receive electromagnetic waves. The antenna2304may be constructed from materials such as metals, alloys, and composites. For example, the antenna2304may be made of copper or copper alloys. The antenna2304may be constructed to have different shapes based on the power transfer requirements. In the exemplary system2300shown inFIG.23, the antenna2304is constructed as a hybrid dipoles comprising a first spiral pole2320aand a second spiral pole2320b. A first power feed line supplying current to the first spiral pole2320amay be provided through a first via2305aand a second power feed supplying current the second spiral pole2320bmay be provided through a second via2305b. The antenna segments in each of the spiral poles2320may mutually cancel the electromagnetic radiation in the far field generated by the spiral dipoles2320thereby reducing the transfer of power to the far field. For example, the antenna segments in the first spiral pole2320amay cancel the far field electromagnetic radiation generated by each other. Additionally, or in the alternative, the far field radiation generated by one or more antenna segments of the first spiral pole2320amay be cancelled by the far field radiation generated by one or more antenna segments of the second spiral pole2320b. One ordinarily skilled in the art will appreciate the cancellation of electromagnetic radiation in the far field and absence of such cancellation in the near-field is dictated by one or more solutions of Maxwell's equations for time-varying electric and magnetic fields generated by the currents flowing in opposite directions. The power transfer system2300may include a ground plane (not shown) at or above the bottom surface. The ground plane may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane may be formed by copper or a copper alloy. In some embodiments, the ground plane may be constructed of a solid sheet of material. In other embodiments, the ground plane may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The vias2305carrying the power feed lines to the antenna may pass through the ground plane. In some embodiments, the ground plane may be electrically connected to the antenna. In some embodiments, the ground plane may not be electrically connected to the antenna2304. For such implementations, an insulation area to insulate the vias2305from the ground plane may be constructed between the vias2305and the ground plane. In some embodiments, the ground plane may act as a reflector of the electromagnetic waves generated by the antenna2304. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system2300by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antenna2304from or towards the top surface2301. Therefore, there may be no leakage of electromagnetic power from the bottom surface. The hybrid antenna2304may be required for wideband and/or multiband designs. For example, a non-hybrid structure may be highly efficient at a first frequency and at a first distance between the transmitter and the receiver, but may be at inefficient other frequencies and distances. Incorporating more complex structure such as a hybrid antenna2304may allow for higher efficiencies along a range of frequencies and distances. FIG.24AandFIG.24Bschematically illustrate a top perspective view and a side perspective view respectively of an exemplary near-field power transfer system2400, according to an embodiment of the disclosure. In some embodiments, the power transfer system2400may be a part of or associated with a power transmitter. In other embodiments, the power transfer system100may be a part of or associated with a power receiver. The power transfer system2400may comprise a housing defined by a top surface2401, a bottom surface2402, and sidewalls2403. In some embodiments, the housing may be constructed of a material creating minimal obstructions for electromagnetic waves to pass through. In other embodiments, different portions of the housing may be constructed with materials having different electromagnetic properties such as permeability and permittivity. For example, the top surface2401may allow electromagnetic waves to pass through with minimal obstruction while the sidewalls2403may obstruct electromagnetic waves by attenuation, absorption, reflection, or other techniques known in the art. A substrate2407may be disposed within a space defined between the top surface2401, sidewalls2403, and the bottom surface2402. In some embodiments, the power transfer system2400may not include a housing and the substrate2407may include the top surface2401, sidewalls2403, and the bottom surface2402. The substrate2407may comprise any material capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. The metamaterials may be a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. The metamaterials disclosed herein may receive radiation or may transmit radiation, and may act as thin reflectors. The power transfer system may include hierarchical antennas2404that may be constructed on or below the top surface2401. When the power transfer system2400is a part of or associated with a power transmitter, the antennas2404may be used for transmitting electromagnetic waves. Alternatively, when the power transfer system2400is a part of or associated with a power receiver, the antennas2404may be used for receiving electromagnetic waves. In some embodiments, the power transfer system2400may operate as a transceiver and the antennas2404may both transmit and receive electromagnetic waves. The antennas2404may be constructed from materials such as metals, alloys, and composites. For example, the antennas2404may be made of copper or copper alloys. The antennas2404may be constructed to have different shapes based on the power transfer requirements. In the exemplary system2400shown inFIG.24AandFIG.24B, the antennas2404are constructed in a hierarchical spiral structure with a level zero hierarchical antenna2404aand a level one hierarchical antenna2404b. Each of the hierarchical antennas2404may include antenna segments, wherein antenna segments have currents flowing in the opposite directions to cancel out the far field radiations. For example, the antenna segments in the level zero hierarchical antenna2404amay cancel the far field electromagnetic radiation generated by each other. Additionally, or in the alternative, the far field radiation generated by one or more antenna segments of the level_zero hierarchical antenna2404amay be cancelled by the far field radiation generated by one or more antenna segments of the level_one hierarchical antenna2404b. A power feed line (not shown) to the antennas is carried through a via2405. The power feed line may supply current to the antenna2404. The power transfer system2400may include a ground plane2406at or above the bottom surface2402. The ground plane2406may be formed by materials such as metal, alloys, and composites. In an embodiment, the ground plane2406may be formed by copper or a copper alloy. In some embodiments, the ground plane2406may be constructed of a solid sheet of material. In other embodiments, the ground plane2406may be constructed using material strips arranged in shapes such as loops, spirals, and meshes. The via2405carrying a power feed line to the antenna may pass through the ground plane2406. In some embodiments, the ground plane2406may be electrically connected to one or more of the antennas2404. In some embodiments, the ground plane2406may not be electrically connected to the antennas2404. For such implementations, an insulation area2408to insulate the via2405from the ground plane2406may be constructed between the via2405and the ground plane2406. In some embodiments, the ground plane2406may act as a reflector of the electromagnetic waves generated by the antennas2404. In other words, the ground plane may not allow electromagnetic transmission beyond the bottom surface of the power transfer system2400by cancelling and/or reflecting the transmission image formed beyond the bottom surface. Reflecting the electromagnetic waves by the ground plane may reinforce the electromagnetic waves transmitted by the antennas2404from or towards the top surface2401. Therefore, there may be no leakage of electromagnetic power from the bottom surface2402. In some embodiments, there may be multiple ground planes, with a ground plane for each of the hierarchical antennas2404. In some embodiments, the hierarchical antennas have different power feed lines carried through multiple vias. The hierarchical antennas2404may be required for wideband and/or multiband designs. For example, a non-hierarchical structure may be highly efficient at a first frequency and at a first distance between the transmitter and the receiver, but may be inefficient at other frequencies and distances. Incorporating more complex structures, such as hierarchical antennas2404, may allow for higher efficiencies along a range of frequencies and distances. FIGS.25A-25Hillustrate various views of a representative near-field antenna2500in accordance with some embodiments. It is noted that the representative near-field antenna2500, and its various components, may not be drawn to scale. Moreover, while some example features are illustrated, various other features have not been illustrated for the sake of brevity and so as not to obscure pertinent aspects of the example implementations disclosed herein. In some instances, the near-field antenna2500is referred to as a “quad-pol antenna element.” In some embodiments, the near-field antenna2500is part of the charging pad100, e.g., one or more of the near-field antennas2500are included in each of the antenna zones290(FIG.1B). In some embodiments, the near-field antennas2500are the only antennas included in each of the antenna zones while, in other embodiments, the near-field antennas2500can be included in respective antenna zones along with other antennas described herein. In still other embodiments, the near-field antennas2500can be included as the only antennas in certain of the antenna zones, while other antenna zones may include only other types of antennas that are described herein. FIG.25Ashows an isometric view of the near-field antenna2500in accordance with some embodiments. As shown, the near-field antenna2500includes a substrate2506offset from a reflector2504(e.g., offset along the z-axis), and thus a gap is formed between the reflector2504and substrate2506. In such an arrangement, the reflector2504defines a first plane (e.g., a first horizontal plane: the bottom surface) and the substrate2506defines a second plane (e.g., a second horizontal plane: the top surface) that is offset from the first plane. In some embodiments, the substrate2506is made from a dielectric, while in other embodiments the substrate2506is made from other materials capable of insulating, reflecting, absorbing, or otherwise housing electrical lines conducting current, such as metamaterials. Metamaterials are a broad class of synthetic materials that are engineered to yield desirable magnetic permeability and electrical permittivity. At least one of the magnetic permeability and electrical permittivity may be based upon power-transfer requirements, and/or compliance constraints for government regulations. In various embodiments, the metamaterials disclosed herein can be used to receive radiation, transmit radiation, and/or as reflectors. In some embodiments, the reflector2504is a metal sheet (e.g., copper, copper alloy, or the like) while in other embodiments the reflector2504is a metamaterial. The reflector2504is configured to reflect some electromagnetic signals radiated by the near-field antenna2500. In other words, the reflector2504may not allow electromagnetic transmission beyond the bottom surface of the near-field antenna2500by reflecting the electromagnetic signals radiated by the near-field antenna2500. Additionally, reflecting the electromagnetic signals by the reflector2504can redirect some of the electromagnetic signals transmitted by antenna elements of the near-field antenna2500from or towards the substrate2506. In some instances, the reflector2504reduces far-field gain of the near-field antenna2500. In some embodiments, the reflector2504also cancels some electromagnetic signals radiated by the near-field antenna2500. The substrate2506further includes four distinct coplanar antenna elements (also referred to herein as “radiating elements”), where each of the four distinct antenna elements follows a respective meandering pattern. The four distinct coplanar antenna elements may each occupy a distinct quadrant of the substrate. The coplanar antenna elements may be embedded in the substrate2506, such that respective first surfaces of the coplanar antenna elements are coplanar with a top surface of the substrate2506, and respective second surfaces, opposite the respective first surfaces, of the coplanar antenna elements are coplanar with a bottom surface of the substrate2506. The respective meandering patterns are used to increase an effective length of each of the four distinct coplanar antenna elements, thus resulting in a lower resonant frequency of the antenna2500while reducing an overall size of the antenna2500. In some embodiments, the respective meandering patterns are all the same while, in other embodiments, one or more of the respective meandering patterns differ. Each of the four distinct coplanar antenna elements includes a plurality of continuous (and/or contiguous) segments, which are discussed below with reference toFIG.25F. In some embodiments (not shown), a shape of each segment in the plurality of segments is substantially the same (e.g., each is rectangular or some other shape). Alternatively, in some other embodiments, a shape of at least one segment in the plurality of segments differs from shapes of other segments in the plurality of segments. It is noted that various combinations of shapes can be used to form the segments of a respective antenna element, and the shapes shown inFIG.25Aare merely illustrative examples. Further, in some embodiments, the substrate2506is not included and the four distinct coplanar antenna elements are made from stamped metal (i.e., the radiating elements are sitting in open space above the reflector2504). The four distinct coplanar antenna elements are shown inFIG.25Aas a first radiating element2502-A, a second radiating element2502-B, a third radiating element2502C, and a fourth radiating element2502-D. The first radiating element2502-A and the second radiating element2502-B together compose (i.e., form) a first dipole antenna2501-A positioned along (e.g., center on) a first axis (e.g., the X-axis). In other words, the first radiating element2502-A is a first pole of the first dipole antenna2501-A and the second radiating element2502-B is a second pole of the first dipole antenna2501-A. The first dipole antenna2501-A is indicated by the dashed line. In addition, the third radiating element2502-C and the fourth radiating element2502-D together compose (i.e., form) a second dipole antenna2501-B positioned along a second axis (e.g., the Y-axis) perpendicular to the first axis. In other words, the third radiating element2502-C is a first pole of the second dipole antenna2501-B and the fourth radiating element2502-D is a second pole of the second dipole antenna2501-B. The second dipole antenna2501-B is indicated by the dashed-dotted line. FIG.25Bshows another isometric view (e.g., isometric underneath view) of the near-field antenna2500in accordance with some embodiments. For ease of illustration, the reflector2504is not shown inFIG.25B. As shown, the near-field antenna2500further includes a first feed2508-A and a second feed2508-B attached to a central region of the substrate2504. The first feed2508A is connected to the first and second radiating elements2502-A,2502-B forming the first dipole antenna2501-A. More specifically, the first feed2508-A is connected to the second radiating element2502-B via a connector2512-A (FIG.25C) and to the first radiating element2502-A via an intra-dipole connector2510-A. The first feed2508-A is configured to supply electromagnetic signals that originate from a power amplifier (e.g., power amplifier108,FIG.26) to the first and second radiating elements2502-A,2502-B. The second feed2508-B is connected to the third and fourth radiating elements2502-C,2502-D forming the second dipole antenna2501-B. More specifically, the second feed2508-B is connected to the fourth radiating element2502-D via a connector2512-B (FIG.25C) and to the third radiating element2502-C via an intra-dipole connector2510-B. The second feed2508-B is configured to supply electromagnetic signals that originate from the power amplifier to the third and fourth radiating elements2502-C,2502-D. The four radiating elements are configured to radiate the provided electromagnetic signals (e.g., radio frequency power waves), which are used to power or charge a wireless-power-receiving device. In some embodiments, as explained below in detail, the four radiating elements do not radiate at the same time. Instead, based on information about a wireless-power receiving device, either the first dipole antenna2501-A is supplied the electromagnetic signals or the second dipole antenna2501-B is supplied electromagnetic signals. The electromagnetic signals radiated by the first dipole antenna2501-A have a first polarization and the electromagnetic signals radiated by the second dipole antenna2501B have a second polarization perpendicular to the first polarization. The differences in polarization are attributable, at least in part, to the orientations of the first and second dipole antennas2501-A,2501-B. For example, the first dipole antenna2501-A is positioned along the first axis (e.g., the X-axis) and the second dipole antenna2501-B is positioned along the second axis (e.g., the Y-axis), which is perpendicular to the first axis. Thus, in some instances, the electromagnetic signals are fed to the dipole antenna whose polarization matches a polarization of a power-receiving-antenna of a wireless-power-receiving device. A process for selectively coupling one of the dipole antennas to an electromagnetic signals feeding source (i.e., a power amplifier108) is described below in method3000(FIG.30). For ease of discussion below, the substrate2506and the radiating elements2502-A-2502-D are referred to collectively as the “radiator2507” when appropriate. FIGS.25C-25Dshow different side views of the near-field antenna2500, where the side view inFIG.25Dis rotated 90 degrees relative to the side view inFIG.25C. In certain embodiments or circumstances, the first feed2508-A is connected to the second radiating element2502-B by the connector2512-A and to the first radiating element2502-A by the intra-dipole connector2510-A (FIG.25Balso shows the intra-dipole connector2510-A). In certain embodiments or circumstances, the second feed2508-B is connected to the fourth radiating element2502-B by the connector2512-B and to the third radiating element2502-C by the intra-dipole connector2510-B (FIG.25Balso shows the intra-dipole connector2510-B). FIG.25Eshows another side view of the near-field antenna2500in accordance with some embodiments. As shown, the first and second feeds2508-A,2508-B are substantially perpendicular to the radiator2507. For example, each of the feeds2508-A,2508-B is disposed along a respective vertical axis while the antenna2507is disposed along a horizontal axis/plane. Further, the first and second feeds2508-A,2508-B are connected at a first end to the antenna2507, and are connected at a second end, opposite the first end, to a printed circuit board2514and a ground plane2516. In some embodiments, the printed circuit board2514and the ground plate2516compose the reflector2504. Alternatively, in some embodiments, the reflector2504is a distinct component, which is offset from the printed circuit board2514and the ground plane2516(e.g., positioned between the antenna2507and the printed circuit board2514). In this arrangement, the reflector2504may define openings (not shown), and the first and second feeds2508-A,2508-B may pass through said openings. As shown in the magnified view2520, the first feed2508-A includes a feedline2524-A (e.g., a conductive metal line) housed (i.e., surrounded) by a shield2522-A. The feedline2524-A is connected to metal traces (e.g., communication buses208,FIG.26) of the printed circuit board2514by a metal deposit2526-A. Further, the shield2522-A contacts the ground plane2516, thereby grounding the first dipole2501-A. Similarly, the second feed2508-B includes a feedline2524-B housed by a shield2522-B. The feedline2524-B is connected to metal traces (not shown) of the printed circuit board2514by a metal deposit2526-B. Further, the shield2522-B contacts the ground plane2516, thereby grounding the second dipole2501-B. As explained below with reference toFIG.26, the metal traces of the printed circuit board2514may be connected to one or more additional components (not shown inFIGS.25A-25H) of the near-field antenna2500, including one or more power amplifiers108, an impedance-adjusting component2620, and a switch2630(also referred to herein as “switch circuitry”). Although not shown inFIG.25E, a dielectric may separate the feedline from the shield in each feed (e.g., electrically isolate the two components). Additionally, another dielectric can surround the shield in each feed to protect the shield (i.e., the first and second feeds2508-A,2508-B may be coaxial cables). It is also noted that the particular shapes of the metal deposits2526-A,2526-B can vary in certain embodiments, and the shapes shown inFIG.25Eare examples used for ease of illustration. FIG.25Fshows a representative radiating element2550following a meandering pattern in accordance with some embodiments. As shown, the representative radiating element2550includes: (i) a first plurality of segments2560-A-2560-D, and (ii) a second plurality of segments2562-A-2562-C interspersed between the first plurality of segments2560-A-2560-D (separated by dashed lines). In some embodiments, the first plurality of segments2560-A-2560-D and the second plurality of segments2562-A-2562C are continuous segments. Alternatively, in some other embodiments, the first plurality of segments2560-A-2560-D and the second plurality of segments2562-A-2562-C are contiguous segments (e.g., ends of neighboring segments abut one another). The illustrated boundaries (e.g., the dashed lines) separating the segments inFIG.25Fare merely one example set of boundaries that is used for illustrative purposes only, and one of skill in the art will appreciate (upon reading this disclosure) that other boundaries (and segment delineations) are within the scope of this disclosure. As shown, lengths of segments in the first plurality of segments2560-A-2560-D increase from a first end portion2564of the radiating element2550to a second end portion2566of the radiating element2550. In some embodiments, while not shown, lengths of segments in the second plurality of segments2562-A-2562-C increase from the first end portion2564of the radiating element2550to the second end portion2566of the radiating element2550. Alternatively, in some other embodiments, lengths of segments in the second plurality of segments2562-A-2562-C remain substantially the same from the first end portion2564of the radiating element2550to the second end portion2566of the radiating element2550. In the illustrated embodiment, the lengths of the first plurality of segments2560-A-2560-D are different from the lengths of the second plurality of segments2562-A-2562-C. Further, the lengths of the first plurality of segments2560-A-2560-D toward the second end portion2566of the radiating element2550are greater than the lengths of the second plurality of segments2562-A-2562-C toward the second end portion2566of the radiating element2550. In some embodiments, the shape of the radiating element provides certain important advantages. For example, the specific shape of the representative radiating element2550shown inFIG.25Fprovides the following advantages: (i) the shape allows two perpendicularly-positioned dipoles to fit in a small area and occupy four quadrants of the substrate2506where each pair of quadrants is perpendicular to each other, and (ii) the width and gaps between segments of neighboring radiating elements (i.e., spacing between quadrants) can be varied to tune the near-field antenna2500to a desired frequency, while still maintaining the radiating elements' miniaturized form-factor. To illustrate numeral (i), with reference toFIG.25A, the first and second radiating elements2502-A,2502-B occupy a first pair of quadrants that include sides of the near-field antenna that are along the Y-axis. Further, the third and fourth radiating elements2502-C,2502-D occupy a second pair of quadrants that include sides of the near-field antenna that are along the X-axis. Accordingly, the first and second pairs of quadrants of the substrate2506include sides of the NF antenna that are perpendicular to each other (e.g., this feature is facilitated, in part, by a width of each radiating element increasing from a central portion of the near-field antenna2500to a respective side of the near-field antenna2500). FIG.25Gshows a top view of the representative near-field antenna2500in accordance with some embodiments. Dimensions of the near-field antenna2500can effect an operating frequency of the near-field antenna2500, radiation efficiency of the near-field antenna2500, and a resulting radiation pattern (e.g., radiation pattern2800,FIG.28A) produced by the near-field antenna2500, among other characteristics of the NF antenna2500. As one example, the near-field antenna2500, when operating at approximately 918 MHz has the following dimensions (approximately): D1=9.3 mm, D2=12.7 mm, D3=23.7 mm, D4=27 mm, D5=32 mm, D6=37.5 mm, D7=10.6 mm, D8=5.1 mm, D9=10.6 mm, D10=5.5 mm, D11=2.1 mm, and D12=28 mm. Further, the reflector2504may have a width of 65 mm, a height of 65 mm, and a thickness of 0.25 mm. FIG.25Hshows another top view of the representative near-field antenna2500in accordance with some embodiments. As shown, the four distinct coplanar antenna elements each occupy a distinct quadrant of the substrate2506(e.g., occupy one of the quadrants2570-A through2570-D, demarcated by the dash-dotted lines). Further, (i) a first end portion2564of the respective meandering pattern followed by each of the four distinct antenna elements borders a central portion2574(dotted line) of the near-field antenna2500, and (ii) a second end portion2566of the respective meandering pattern followed by each of the four distinct antenna elements borders one of the edges2572-A-2572-D of the near-field antenna2500. In such an arrangement, a longest dimension of the respective meandering pattern followed by each of the four distinct antenna elements (e.g., segment2560-D) is closer to a distinct edge2572of the near-field antenna than to the central portion2574of the near-field antenna2500. Moreover, a shortest dimension of the respective meandering pattern followed by each of the four distinct antenna elements is closer to the central portion2574of the near-field antenna2500than a distinct edge2572of the near-field antenna2500. Thus, a width of each of the four distinct antenna elements increases, in a meandering fashion, from the central portion2574of the near-field antenna2500to a respective edge2572of the near-field antenna2500. Furthermore, in some embodiments, the longest dimension of the respective meandering pattern parallels the distinct edge2572. As shown inFIG.27, the near-field antenna2500(when it includes a reflector) creates substantially uniform radiation pattern2700that has minimal far-field gain. The dimensions provided above are merely used for illustrative purposes, and a person of skill in the art (upon reading this disclosure) will appreciate that various other dimensions could be used to obtain acceptable radiation properties, depending on the circumstances. FIG.26is a block diagram of a control system2600used for controlling operation of certain components of the near-field antenna2500in accordance with some embodiments. The control system2600may be an example of the charging pad100(FIG.1A), however, one or more components included in the charging pad100are not included in the control system2600for ease of discussion and illustration. The control system2600includes an RF power transmitter integrated circuit160, one or more power amplifiers108, an impedance-adjusting component2620, and the near-field antenna2500, which includes the first and second dipole antennas2501-A,2501B. Each of these components is described in detail above, and the impedance-adjusting component2620is described in more detail below. The impedance-adjusting component2620may be an RF termination or load, and is configured to adjust an impedance of at least one of the first and second dipole antennas2501-A,2501-B. Put another way, the impedance-adjusting component2620is configured to change an impedance one of the dipole antennas, thereby creating an impedance mismatch between the two dipole antennas. By creating an impedance mismatch between the two dipole antenna, mutual coupling between the two dipole antennas is substantially reduced. It is noted that the impedance-adjusting component2620is one example of an antenna-adjusting component. Various other antenna-adjusting components might be used (e.g., to change an effective length of any of the radiating elements) to adjust various other characteristics of the antenna (e.g., such as length of the respective antenna elements of each dipole), in order to ensure that one of the two dipoles is not tuned to a transmission frequency of the other dipole. The control system2600also includes a switch2630(also referred to herein as “switch circuitry”) having one or more switches therein (not shown). The switch2630is configured to switchably couple the first and second dipole antennas2501-A,2501-B to the impedance-adjusting component2620and at least one power amplifier108, respectively (or vice versa), in response to receiving one or more instructions in the form of electrical signals (e.g., the “Control Out” signal) from the RF power transmitter integrated circuit160. For example, the switch2630may couple, via one or more switches, the first dipole antenna2501-A with the impedance-adjusting component2620and the second dipole antenna2501B with at least one power amplifier108, or vice versa. To accomplish the switching discussed above, the switch2630provides distinct signal pathways (e.g., via the one or more switches therein) to the first and second dipole antennas2501-A,2501-B. Each of the switches, once closed, creates a unique pathway between either: (i) a respective power amplifier108(or multiple power amplifiers108) and a respective dipole antenna, or (ii) the impedance-adjusting component2620and a respective dipole antenna. Put another way, some of the unique pathways through the switch2630are used to selectively provide RF signals to one of the dipole antennas2501-A,2501-B while some of the unique pathways through the switch2630are used to adjust an impedance of one of the dipole antennas2501-A,2501-B (i.e., detune the dipole antennas2501-A,2501B). It is noted that two or more switches of the switch circuitry may be closed at the same time, thereby creating multiple unique pathways to the near-field antenna2500that may be used simultaneously. As shown, the RF power transmitter integrated circuit160is coupled to the switch2630via busing208. The integrated circuit160is configured to control operation of the one or more switches therein (illustrated as the “Control Out” signal inFIGS.1A,1C, and26). For example, the RF power transmitter integrated circuit160may close a first switch in the switch2630, which connects a respective power amplifier108with the first dipole antenna2501-A, and may close a second switch in the switch2630that connects the impedance-adjusting component2620with the second dipole antenna2501-B, or vice versa. Moreover, the RF power transmitter integrated circuit160is coupled to the one or more power amplifiers108and is configured to cause generation of a suitable RF signal (e.g., the “RF Out” signal) and cause provision of the RF signal to the one or more power amplifiers108. The one or more power amplifiers108, in turn, are configured to provide the RF signal (e.g., based on an instruction received from the RF power transmitter integrated circuit160) to one of the dipole antennas via the switch2630, depending on which switch (or switches) in the switch circuitry2630is (are) closed. In some embodiments, the RF power transmitter integrated circuit160controller is configured to control operation of the switch2630and the one or more power amplifiers108based on one or more of: (i) a location of a wireless-power-receiving device near (or on) the near-field antenna2500, (ii) a polarization of a power-receiving-antenna of the wireless-power-receiving device, and (iii) a spatial orientation of the wireless-power-receiving device. In some embodiments, the RF power transmitter integrated circuit160receives information that allows the circuit160to determine (i) the location of the wireless-power-receiving device, (ii) the polarization of the power-receiving-antenna of the wireless-power-receiving device, and (iii) the spatial orientation of the wireless-power-receiving device from the wireless-power-receiving device. For example, the wireless-power-receiving device can send one or more communications signals to a communication radio of the near-field antenna2500indicating each of the above (e.g., data in the one or more communications signals indicates the location, polarization, and/or orientation of the wireless-power-receiving device). Further, as shown inFIG.1A, the wireless communication component204(i.e., the communication radio of the near-field antenna2500) is connected to the RF power transmitter integrated circuit160. Thus, the data received by the wireless communication component204can be conveyed to the RF power transmitter integrated circuit160. In some embodiments, the first dipole antenna2501-A may be configured to radiate electromagnetic signals having a first polarization (e.g., horizontally polarized electromagnetic signals) and the second dipole antenna2501-B may be configured to radiate electromagnetic signals having a second polarization (e.g., vertically polarized electromagnetic signals) (or vice versa). Further, if the power-receiving-antenna of the wireless-power-receiving device is configured to receive electromagnetic signals having the first polarization, then the RF power transmitter integrated circuit160will connect the first dipole antenna2501-A to the one or more power amplifiers108and will connect the impedance-adjusting component2620with the second dipole antenna2501-B, via the switch2630. In this way, the electromagnetic signals radiated by the near-field antenna2500will have a polarization that matches the polarization of the target device, thereby increasing an efficiency of energy transferred to the wireless-power-receiving device. In some embodiments, the switch2630may be part of (e.g., internal to) the near-field antenna2500. Alternatively, in some embodiments, the switch2630is separate from the near-field antenna2500(e.g., the switch2630may be a distinct component, or may be part of another component, such as the power amplifier(s)108). It is noted that any switch design capable of accomplishing the above may be used. FIG.27shows a radiation pattern2700generated by the near-field antenna2500when it does include the back reflector2504(i.e., the radiating antenna elements are “backed” by the metallic reflector). The illustrated radiation pattern2700is generated by the near-field antenna2500when (i) the first dipole antenna2501-A is fed electromagnetic signals by the one or more power amplifiers108, and (ii) the near-field antenna2500includes the reflector2504. As shown, the radiation pattern2700has a higher concentration of EM energy produced along the X-axis and Y-axis (and has a radiation null along the Z-axis) and forms an overall torus shape. As such, the electromagnetic field concentration stays closer to the NF antenna2500and far-field gain is minimized (e.g., the EM field concentration stays closer to the radiator2507and the reflector2504,FIG.25E). Although not shown, the radiation pattern2700is polarized in a direction that is aligned with the X-axis. Thus, by incorporating the reflector2504, the radiation pattern2700is rotated 90 degrees about the X-axis relative to the radiation pattern2800(FIG.28A, discussed below). Additionally, by incorporating the reflector2504, a radiation null is formed along the Z-axis, which substantially reduces far-field gain, and energy radiated by the near-field antenna2500is concentrated within a near-field distance from the near-field antenna2500. Again, the second dipole antenna2501-B may be connected to the impedance-adjusting component2620when the first dipole antenna2501-A is fed the electromagnetic signals. FIG.28AtoFIG.28Cshow various radiation patterns generated by an embodiment of the near-field antenna2500that does not include the reflector2504. The radiation pattern2800illustrated inFIG.28Ais generated by the near-field antenna2500when the first dipole antenna2501-A is fed electromagnetic signals by the one or more power amplifiers108. As shown, the radiation pattern2800has a higher concentration of EM energy produced along the Z-axis and the X-axis (and has a radiation null along the Y-axis) and forms an overall torus shape. This pattern2800shows that an antenna element, without the reflector, radiates outward/perpendicular to the near-field antenna2500. Although not shown, the radiation pattern2800is polarized in a first direction (e.g., aligned with the X-axis). Furthermore, the second dipole antenna2501-B may be connected to the impedance-adjusting component2620when the first dipole antenna2501-A is fed the electromagnetic signals by the one or more power amplifiers108. The radiation pattern2810illustrated inFIG.28Bis generated by the near-field antenna2500when the second dipole antenna2501-B is fed electromagnetic signals by the one or more power amplifiers108(i.e., the first dipole antenna2501-A is not fed electromagnetic signals and instead may be connected to the impedance-adjusting component2620).FIG.28Bshows that the radiation pattern2810that has a higher concentration of EM energy produced along the Z-axis and the Y-axis (and has a radiation null along the X-axis), which also forms an overall torus shape. Although not shown, the radiation pattern2810is polarized in a second direction (e.g., aligned with the Y-axis). Accordingly, the first dipole antenna2501-A is configured to generate a radiation pattern2800polarized in the first direction while the second dipole antenna2501-B is configured to generate a radiation pattern2810polarized in the second direction perpendicular to the first direction. In this way, the first dipole antenna2501-A is fed when the polarization of the electromagnetic signals generated by the first dipole antenna2501-A match a polarization of a power-receiving antenna of a wireless-power-receiving device. Alternatively, the second dipole antenna2501-D is fed when the polarization of the electromagnetic signals generated by the second dipole antenna2501-B match a polarization of a power-receiving antenna of a wireless-power-receiving device. FIG.28Cshows a radiation pattern2820generated when both the first and second dipole antennas are fed electromagnetic signals by the one or more power amplifiers108, and neither dipole antenna is connected to the impedance-adjusting component2620. As shown, the radiation pattern2820has higher concentrations of EM energy produced along the Z-axis, X-axis and the Y-axis (and a radiation null is formed between the X-axis and the Y-axis) and forms an overall torus shape. FIGS.29A and29Bshow concentrations of energy radiated and absorbed by dipole antennas of the near-field antenna2500in accordance with some embodiments. In particular,FIG.29Ashows the resulting concentrations of energy radiated and absorbed by the dipole antennas2501-A,2501-B when an impedance of the first dipole antenna2501-A substantially matches an impedance of the second dipole antenna2501-B.FIG.29Bshows the resulting concentrations of energy radiated and absorbed by the dipole antennas2501-A,2501-B of the near-field antenna2500when an impedance of the first dipole antenna2501-A differs from an impedance of the second dipole antenna2501-B, which is achieved by connecting one of the dipole antennas to the impedance-adjusting component2620. Put another way, the first and second dipole antennas2501-A,2501-B are intentionally detuned as a result of one of the dipole antennas being connected to the impedance-adjusting component2620. An absence of impedance mismatch between neighboring antenna elements leads to substantial mutual coupling between neighboring antenna elements. “Mutual coupling” refers to energy being absorbed by one antenna element (or one antenna dipole) when another nearby antenna element (or antenna dipole) is radiating. Antennas (or antenna arrays) with closely spaced antenna elements typically suffer from undesired mutual coupling between neighboring antenna elements, which limits the antenna's ability to radiated efficiency (this problem is particularly acute when the antenna elements are placed close together and when the antenna elements are miniaturized). For example, with reference toFIG.29A, the second dipole antenna2501-B is fed electromagnetic signals by the one or more power amplifiers108, and the coloring along the second dipole antenna2501-B represents different concentrations of energy radiated by the second dipole antenna2501-B, with reds corresponding to high concentrations, greens corresponding to medium concentrations, and blues corresponding to low concentrations. The first dipole antenna2501-A inFIG.29Ais not independently radiating, however, certain amounts of the energy radiated by the second dipole antenna2501-B is absorbed at the first dipole antenna2501-A as a result of the mutual coupling between the two dipole antennas. Because of this mutual coupling, a radiation efficiency of the near-field antenna2500is not optimized (e.g., the NF antenna2500may only be able to transfer 50% or less of the energy it attempts to transmit). In contrast, with reference toFIG.29B, the second dipole antenna2501-B is fed electromagnetic signals by the one or more power amplifiers108. Additionally, the first dipole antenna2501-A is coupled to the impedance-adjusting component2620, thereby creating an intentional impedance mismatch between the two dipole antennas. In such a configuration, the first dipole antenna2501-A inFIG.29Bis absorbing far less energy radiated by the second dipole antenna2501-B compared to an amount of the energy that the first dipole antenna2501-A was absorbing inFIG.29A. Accordingly, a radiation efficiency of the near-field antenna2500inFIG.29Bis higher (e.g., the NF antenna2500may now be able to radiate 90% or greater of the energy it attempts to transmit) than the radiation efficiency of the near-field antenna2500inFIG.29A. Method of Operation FIG.30is a flow diagram showing a method3000of wireless power transmission in accordance with some embodiments. Operations (e.g., steps) of the method3000may be performed by a controller (e.g., RF power transmitter integrated circuit160,FIGS.1A and26) associated with a near-field antenna (e.g., near-field antenna2500,FIG.25A). At least some of the operations shown inFIG.30correspond to instructions stored in a computer memory or computer-readable storage medium (e.g., memory206of the charging pad100,FIG.2A). The method3000includes providing (3002) a near-field antenna that includes a reflector (e.g., reflector2504,FIG.25A) and four distinct coplanar antenna elements (e.g., radiating elements2502-A to2502-D,FIG.25A) offset from the reflector. The four distinct antenna elements follow respective meandering patterns, such as the meandering pattern shown inFIG.25F. Furthermore, (i) two antenna elements of the four coplanar antenna elements form a first dipole antenna (e.g., dipole antenna2501-A,FIG.25A) aligned with a first axis (e.g., X-axis,FIG.25A), and (ii) another two antenna elements (e.g., dipole antenna2501-B,FIG.25A) of the four coplanar antenna elements form a second dipole antenna aligned with a second axis (e.g., Y-axis,FIG.25A) perpendicular to the first axis. In some embodiments, the respective meandering patterns are all the same. In some embodiments, a first antenna element (e.g., first radiating element2502-A) of the four distinct coplanar antenna elements is a first pole of the first dipole antenna and a second antenna element (e.g., second radiating element2502-B) of the four distinct coplanar antenna elements is a second pole of the first dipole antenna. Furthermore, a third antenna element (e.g., third radiating element2502-C) of the four distinct coplanar antenna elements may be a first pole of the second dipole antenna and a fourth antenna element (e.g., fourth radiating element2502-D) of the four distinct coplanar antenna elements may be a second pole of the second dipole antenna. The two antenna elements that form the first dipole antenna can each include two segments that are perpendicular to the first axis, and the other two antenna elements that form the second dipole antenna can each include two segments that parallel the first axis. For example, with reference toFIG.25A, the first and second radiating elements2502-A,2502-B each includes two segments (e.g., segments2560C and2560-D,FIG.25F) that are perpendicular to the X-axis, and the third and fourth radiating elements2502-C,2502-D each includes two segments (e.g., segments2560-C and2560-D,FIG.25F) that are parallel to the X-axis. In such an arrangement, the two antenna elements that form the first dipole antenna are configured to radiate electromagnetic signals having a first polarization, and the two antenna elements that form the second dipole antenna are configured to radiate electromagnetic signals having a second polarization perpendicular to the first polarization. In some embodiments, each of the four distinct antenna elements includes: (i) a first plurality of segments, and (ii) a second plurality of segments interspersed between each of the first plurality of segments. For example, with reference toFIG.25G, the second plurality of segments2562-A-2562-C are interspersed between the first plurality of segments2560-A-2560-D. In such embodiments, first lengths of segments in the first plurality of segments increase from a first end portion of the antenna element to a second end portion of the antenna element, as shown inFIGS.25F and25G. It is noted that the “first end portion” of each antenna element corresponds to the first end portion2564illustrated inFIG.25F, and the first end portion of each antenna element is near a central portion2574(FIG.25H) of the near-field antenna2500. Furthermore, the “second end portion” of each antenna element corresponds to the second end portion2566illustrated inFIG.25F, and the second end portion2566of each antenna element extends towards an edge2572(FIG.25H) of the near-field antenna2500. Thus, put simply, a width of each of the four distinct antenna elements increases, in a meandering fashion, from a central portion of the near-field antenna2500to a respective edge of the near-field antenna2500. In some embodiments, second lengths of segments in the second plurality of segments also increase from the first end portion of the antenna element to the second end portion of the antenna element, while in other embodiments the second lengths of the segments in the second plurality of segments remain substantially the same, as shown inFIG.25F. Additionally, the first lengths of one or more segments in the first plurality of segments are different from the second lengths of the segments in the second plurality of segments. In some embodiments, the first lengths of the first plurality of segments toward the second end portion of the antenna element are greater than the second lengths of the second plurality of segments toward the second end portion of the antenna element. For example, the lengths of segments2560-C and2560-D are substantially longer than the lengths of segments2562-B and2562-C. Segments of the radiating elements are discussed in further detail above with reference toFIGS.25F and25G. In some embodiments, a first end portion of the respective meandering pattern followed by each of the four distinct antenna elements borders a same central portion (e.g., central portion2574,FIG.25H) of the near-field antenna, and a second end portion of the respective meandering pattern followed by each of the four distinct antenna elements borders a distinct edge (e.g., one of the edges2572,FIG.25H) of the near-field antenna. Further, a longest dimension of the respective meandering pattern followed by each of the four distinct antenna elements may be closer to the distinct edge of the near-field antenna than to the same central portion of the near-field antenna. In addition, a shortest dimension of the respective meandering pattern followed by each of the four distinct antenna elements may be closer to the same central portion of the near-field antenna than the distinct edge of the near-field antenna. In some embodiments, the four distinct coplanar antenna elements are formed on or within a substrate. For example, as shown inFIGS.25A and25B, opposing first and second surfaces of the four distinct coplanar antenna elements are exposed and coplanar with opposing first and second surfaces of the substrate2506. It is noted that a dielectric (e.g., thermoplastic or thermosetting polymer) can be deposited over the four distinct coplanar antenna elements so that the antenna elements are protected (may or may not be visible depending on the properties of the dielectric). In some embodiments, the substrate may include a metamaterial of a predetermined magnetic permeability or electrical permittivity. The metamaterial substrate can increase the performance of the near-field antenna as a whole (e.g., increase radiation efficient when compared to a substrate made from a common dielectric). The near-field antenna further includes switch circuitry (e.g., switch2630,FIG.26) coupled to at least two of the four coplanar antenna elements. For example, the near-field antenna may include a first feed (e.g., feed2508-A) with opposing first and second ends, where the first end of the first feed is connected to a first of the two antenna elements composing the first dipole antenna and the second end of the first feed is connected to the switch circuitry, e.g., via metal traces deposited on a printed circuit board2514(FIG.25E). In addition, the near-field antenna may include a second feed (e.g., feed2508-B) with opposing first and second ends, where the first end of the second feed is connected to a first of the two antenna elements composing the second dipole antenna and the second end of the second feed is connected to the switch circuitry, e.g., via metal traces (e.g., busing208) deposited on the printed circuit board2514. The feeds and the printed circuit board are discussed in further detail above with reference toFIG.25E. The near-field antenna also includes a power amplifier (e.g., power amplifier(s)108,FIG.26) coupled to the switch circuitry (e.g., via the metal traces), and an impedance-adjusting component (e.g., component2520,FIG.26) coupled to the switch circuitry (e.g., via the metal traces). The near-field antenna may also include a controller (e.g., RF power transmitter integrated circuit160,FIGS.1A and26) configured to control operation of the switch circuitry and the power amplifier. The controller may be connected to the switch circuitry and the power amplifier via the metal traces. The power amplifier, the impedance-adjusting component, and the controller are discussed in further detail above with reference toFIG.26. The method3000further includes instructing (3004) the switch circuitry to couple: (i) the first dipole antenna to the power amplifier, and (ii) the second dipole antenna to the impedance-adjusting component (or vice versa). For example, with reference toFIG.26, the integrated circuit160may send the “Control Out” signal to the switch circuitry2630, which causes one or more first switches in the switch circuitry2630to close and connect a respective power amplifier108with the first dipole antenna2501-A. The “Control Out” signal also causes one or more second switches in the switch circuitry2630to close and connect the impedance-adjusting component2620with the second dipole antenna2501-B. It is noted that, in some embodiments, the switch circuitry2630includes first and second switch circuits. In such embodiments, the first switch circuit is closed to connect the first dipole antenna to the power amplifier and the second dipole antenna to the impedance-adjusting component. Further, the second switch circuit is closed to connect the first dipole antenna to the impedance-adjusting component and the second dipole antenna to the power amplifier. Controlling operation of the switch circuitry2630is discussed in further detail above with reference toFIG.26. The one or more signals generated and provided by the controller may be based on information received from a wireless-power-receiving device (e.g., receiver104,FIG.2B). For example, the controller may receive location information for the wireless-power-receiving device, (ii) polarization information for a power-receiving-antenna of the wireless-power-receiving device, and/or (iii) orientation information for the wireless-power-receiving device, each of which may be received from the wireless-power-receiving device. Further, the one or more electrical signals may be based on this received information. Put another way, the controller may be configured to control operation of the switch circuitry and the power amplifier based on one or more of: (i) a location of a wireless-power-receiving device (as indicated by the location information), (ii) a polarization of a power-receiving-antenna of the wireless-power-receiving device (as indicated by the polarization information), and (iii) an orientation of the wireless-power-receiving device (as indicated by the orientation information). As explained above with reference toFIG.26, the switch circuitry is configured to switchably couple the first and second dipole antennas2501-A,2501-B to the impedance-adjusting component2620and the power amplifier108, respectively (or vice versa), in response to receiving one or more electrical signals from the RF power transmitter integrated circuit160(e.g., the “Control Out” signal). Further, in some embodiments, the switch circuitry may be configured to switchably couple the first dipole antenna to the power amplifier and the second dipole antenna to the impedance-adjusting component when the near-field antenna is in a first operation mode. Moreover, the switch circuitry may be configured to switchably couple the second dipole antenna to the power amplifier and the first dipole antenna to the impedance-adjusting component when the near-field antenna is in a second operation mode distinct from the first operation mode. The method3000further includes instructing (3006) the power amplifier to feed electromagnetic signals to the first dipole antenna via the switch circuitry. For example, with reference toFIG.26, the integrated circuit160sends the “RF Out” signal to the power amplifier. The power amplifier may, in turn, amplify (if needed) the received “RF Out” signal, and then provide the amplified RF signal to the first dipole antenna via the switch circuitry. The electromagnetic signals, when fed to the first dipole antenna, cause the first dipole antenna to radiate electromagnetic signals to be received by the wireless-power-receiving device, which is located within a threshold distance from the near-field antenna. The wireless-power-receiving device can use energy from the radiated electromagnetic signals, once received, to power or charge an electronic device coupled with the wireless-power-receiving device. Additionally, because the second dipole antenna is connected to the impedance-adjusting component and the first dipole antenna is not, an impedance of the second dipole antenna is adjusted (by the impedance-adjusting component) so that the impedance of the second dipole antenna differs from an impedance of the first dipole antenna. In such an arrangement, the first dipole antenna and the second dipole antenna are detuned (e.g., an operating frequency of the first dipole antenna differs from an operating frequency of the second dipole antenna). In some embodiments, the method3000further includes reflecting, by the reflector, at least a portion of the electromagnetic signals radiated by the first dipole antenna. In addition, in some embodiments, the method3000further includes cancelling, by the reflector, at least a portion of the electromagnetic signals radiated by the first dipole antenna. All of these examples are non-limiting and any number of combinations and multi-layered structures are possible using the example structures described above. Further embodiments also include various subsets of the above embodiments including embodiments inFIGS.1-30combined or otherwise re-arranged in various embodiments, as one of skill in the art will readily appreciate while reading this disclosure. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof It will also be understood that, although the terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first region could be termed a second region, and, similarly, a second region could be termed a first region, without changing the meaning of the description, so long as all occurrences of the “first region” are renamed consistently and all occurrences of the “second region” are renamed consistently. The first region and the second region are both regions, but they are not the same region. The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. | 232,740 |
11863002 | DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative implementations described in the detailed description, drawings, and claims are not meant to be limiting. Other implementations may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. Turning toFIG.1, depicted therein is an exploded left top front perspective view of holder assembly10. Depicted implementation of holder assembly10is shown to include container assembly12, curvilinearly formed semi-rigid sheet assembly14, side assembly16, and side assembly18. Depicted implementation of container assembly12(e.g. box assembly) is shown to include side portion12a, side portion12b, side portion12c, side portion12d, and base portion12eshown to in part bound an interior area with each of their interior surface portions. In implementations, side portion12aand side portion12care opposingly spaced from one another and side portion12band side portion12dare opposingly spaced from one another. As shown side portion12a, side portion12b, side portion12c, side portion12dhave exterior surface portions facing away from the interior area. As depicted, base portion12eis being planarly formed to include an interior surface portion occupying a portion of a plane. Implementations of one or more portions of container assembly12can include at least one of the following materials: rigid plastic, polycarbonate, acrylonitrile butadiene styrene, thermoplastic polymer, thermoplastic polyurethane, polyethylene terephthalate, and nylon. Depicted implementation of side portion12ais shown to include edge12a1, edge12a2, protrusion12a3with aperture12a3a, and protrusion12a4with aperture12a4a. As shown, protrusion12a3and protrusion12a4have top surface portions and bottom surface portions (in implementations depicted as flat), in which the top surface portion are positioned at a first elevation value with respect to when the interior surface portion of the base portion is being horizontally positioned, the bottom surface portion being positioned at a second elevation value with respect to when the interior surface portion of the base portion is being horizontally positioned, the first elevation value of the top surface portion being greater than the second elevation value of the bottom surface portion. Depicted implementation of side portion12bis shown to include protrusion12b1a, corner12b1b, and corner12b1c. Depicted implementation of side portion12bis shown to include curvilinear slot12b2with end portion12b2aand with mid portion12b2b. Depicted implementation of side portion12bis shown to include hook12b3, edge12b4a, edge12b4b, aperture12b5, and aperture12b6. Depicted implementation of side portion12cis shown to include edge12c1, protrusion12c3with aperture12c3a, protrusion12c4with aperture12c4a, and edge12c5. As shown, protrusion12c3and protrusion12c4have top surface portions and bottom surface portions (in implementations depicted as flat), in which the top surface portion are positioned at a first elevation value with respect to when the interior surface portion of the base portion is being horizontally positioned, the bottom surface portion being positioned at a second elevation value with respect to when the interior surface portion of the base portion is being horizontally positioned, the first elevation value of the top surface portion being greater than the second elevation value of the bottom surface portion. Depicted implementation of side portion12dis shown to include protrusion12d1a, corner12d1bwith corner12d1c, and corner12d1d. Depicted implementation of side portion12dis shown to further include curvilinear slot12d2with end portion12d2a, mid portion12d2b, end portion12d2c, and is further shown to include hook12d3. Both curvilinear slot12b2and curvilinear slot12d2are shown to each include being one continuous curve of varying radius of curvature including a first radius of curvature closer to a first end (e.g., end portion12d2a) than a second end (e.g., end portion12d2c), and a second radius of curvature closer to the second end (e.g., end portion12d2c) wherein the first radius of curvature being smaller than the second radius of curvature. Depicted implementation of side portion12dis further shown to include edge12d4a, edge12d4b, edge12d4c, and edge12d4d. Depicted implementation of side portion12dis further shown to include aperture12d5, aperture12d6and coupler12d7, with stem12d7a, aperture12d7b, and stem12d7c, and is shown to further include protrusion12d8and corner12d1d. Depicted implementation of base portion12eis shown to include device interface rear12e1, device interface front12e2, edge12e3, and notch12e4. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is shown to include corner aperture14a1, corner aperture14a2, corner aperture14a3, and corner aperture14a4. In implementations curvilinearly formed semi-rigid sheet assembly14is coupled with container assembly12to include shown a first axis of rotation including through corner aperture14a1and corner aperture14a4about curvilinear slot12d2and curvilinear slot12b2, respectively wherein curvilinear slot12d2and curvilinear slot12b2are shown as opposingly spaced from one another and curvilinearly formed semi-rigid sheet assembly14is shown to be movably couplable to curvilinear slot12d2and curvilinear slot12b2. In implementations curvilinearly formed semi-rigid sheet assembly14is coupled with container assembly12to include a second axis of rotation including through corner aperture14a2and corner aperture14a3about aperture12d6and aperture12b6, respectively. In implementations curvilinearly formed semi-rigid sheet assembly14is coupled with container assembly12to include an axis of translation including through corner aperture14a1and corner aperture14a4about curvilinear slot12d2and curvilinear slot12b2. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is further shown to include member14b1, member14b2, member14b3, and member14b4. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is further shown to include side14c1, side14c2, side14c3, and side14c4. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is further shown to include rear upper surface portion14d1, and front upper surface portion14d2. Depicted implementation of side assembly16is shown to include semi-rigid member16a, spring16b, corner aperture14a3, and coupler assembly16c. Depicted implementation of semi-rigid member16ais shown to include coupler16a1(e.g., threaded member such as screw or bolt), edge16a2, angled portion16a3, coupling portion16a4, aperture16a5, aperture16a6, and aperture16a7. Depicted implementation of spring16bis shown to include coil body16b1, end16b2, and end16b3. Depicted implementation of coupler assembly16cis shown to include coupler16c1with head16c1a, pin portion16c1b, and coupler portion16c1c. Depicted implementation of coupler assembly16cis further shown to include coupler16c2with head16c2a, pin portion16c2b, and coupler portion16c2c. Depicted implementation of side assembly18is shown to include semi-rigid member18a, semi-rigid member18a, and coupler assembly18c. Depicted implementation of semi-rigid member18ais shown to include coupler18a1(e.g. threaded member such as screw, bolt, etc), edge18a2, angled portion18a3, coupling portion18a4, aperture18a5, and aperture18a6, and aperture18a7. Depicted implementation of spring18bis shown to include spring18bwith coil body18b1, end18b2, and end18b3. Depicted implementation of coupler assembly18cis shown to include coupler18c1, with head18c1a, pin portion18c1b, and coupler portion18c1c, and shown to include coupler18c2with head18c2a, pin portion18c2b, and coupler portion18c2c. Turning toFIG.2, depicted therein is a left top front perspective view of holder assembly10. Depicted implementation of base portion12eof container assembly12is shown to include device interface front12e2. As depicted, side portion12ais shown opposingly spaced from curvilinearly formed semi-rigid sheet assembly14. Turning toFIG.3, depicted therein is a left top front perspective view of holder assembly10including spring16b. Turning toFIG.4, depicted therein is an enlarged view of a portion of holder assembly10taken along the dashed rectangle labeled “4” ofFIG.3. Turning toFIG.5, depicted therein is a side elevational view of holder assembly10. As shown, protrusion12a3and protrusion12a4have an elevation value greater than protrusion12c3and protrusion12c4by at least the thickness of protrusion12a3and protrusion12a4. In implementations the bottom surfaces of protrusion12a3and protrusion12a4have an elevation value greater than the top surfaces of protrusion12c3and protrusion12c4. Turning toFIG.6, depicted therein is a top plan view of holder assembly10. Depicted implementation of holder assembly10is shown to include width dimension W1between semi-rigid member16aand semi-rigid member18awhich changes as semi-rigid member16aand semi-rigid member18aadjust to accommodate with a device being held. Depicted implementation of device interface front12e2of base portion12eof container assembly12is shown to include contact12e2a, contact12e2b, and contact12e2c. In implementations the center of aperture12a3aof protrusion12a3is similarly distanced from side portion12aas the center of aperture12a4aof protrusion12a4, which applies similarly to the pair of protrusion12c3and protrusion12c4with respect to distancing from side portion12c. In implementations distancing between aperture centers of protrusion12a3and protrusion12a4are similar or equal to distancing between aperture centers of protrusion12c3and protrusion12c4. Turning toFIG.7, depicted therein is a side-elevational cross-sectional view of holder assembly10taken along the7-7ofFIG.6. As shown, base portion12eincludes a portion that extends past the plane that occupies side portion12cand also past how far the center of aperture12c4aof protrusion12c4extends from side portion12c. Turning toFIG.8, depicted therein is a right top front perspective view of holder assembly10. Depicted implementation of curvilinear slot12b2of side portion12bof container assembly12is shown to include end portion12b2c. Depicted implementation of side portion12bof container assembly12is shown to include edge12b4cand edge12b4d. Depicted implementation of side portion12bof container assembly12is shown to include coupler12b7, and protrusion12b8. Turning toFIG.9, depicted therein is a left bottom front perspective view of holder assembly10. Turning toFIG.10, depicted therein is a right top rear perspective view of holder assembly10. Depicted implementation of base portion12eof container assembly12is shown to include notch12e5. As depicted in implementations, a portion of notch12e5is in vertical alignment (when base portion12eis horizontally oriented) with the center of aperture12c4aof protrusion12c4. Turning toFIG.11, depicted therein is a left bottom rear perspective view of holder assembly10. Turning toFIG.12, depicted therein is a left top front perspective view of housing Depicted implementation of housing20is shown to include side20a, side20b, side20c, side20d, aperture20e, and upper surface20f. Turning toFIG.13, depicted therein is a left top front perspective view of housing containing a plurality of holder assembly10with the plurality of holder assembly10each including curvilinearly formed semi-rigid sheet assembly14in a first position. Turning toFIG.14, depicted therein is a left top front perspective view of housing containing a plurality of holder assembly10with the plurality of holder assembly10one including one curvilinearly formed semi-rigid sheet assembly14in the first position ofFIG.13and other curvilinearly formed semi-rigid sheet assembly14in a various other positions. Turning toFIG.15A, depicted therein is a top plan view of housing20containing a plurality of holder assembly10with curvilinearly formed semi-rigid sheet assembly14in the various positions. Turning toFIG.15B, depicted therein is a top plan view of housing20containing a plurality of holder assembly10with curvilinearly formed semi-rigid sheet assembly14in the various positions. Turning toFIG.15C, depicted therein is a top plan view of housing20containing a plurality of holder assembly10with curvilinearly formed semi-rigid sheet assembly14in the various positions. Turning toFIG.16, depicted therein is a side elevational cross-sectional view of a rear portion of housing20with curvilinearly formed semi-rigid sheet assembly14in the first position ofFIG.13taken along the16-16cutline ofFIG.15A. Depicted implementation of housing20is shown to include base portion20g. Turning toFIG.17, depicted therein is a side elevational cross-sectional view of a front portion of housing20with curvilinearly formed semi-rigid sheet assembly14in a second position taken along the17-17cutline ofFIG.15B. Turning toFIG.18, depicted therein is a side elevational cross-sectional view of a mid portion of housing20with curvilinearly formed semi-rigid sheet assembly14in a third position taken along the18-18cutline ofFIG.15C. As shown inFIGS.16-18, different portions of curvilinearly formed semi-rigid sheet assembly14are closest to side portion12aas the closest distance from curvilinearly formed semi-rigid sheet assembly14to side portion12achange. Turning toFIG.19, depicted therein is a left top front perspective of housing20being coupled with a plurality of device100, each being coupled with device backs110of various thicknesses. Depicted implementations of device backs110are shown to include device back110a, device back110b, device back110c, device back110d, device back110e, and device back110f. Consequently, various curvilinearly formed semi-rigid sheet assembly14of holder assembly10coupled in housing20are depicted as positioned accordingly to which version of device100coupled with a particular device backs110of particular dimension. Turning toFIG.20A, depicted therein is a top plan view of housing20being coupled with a plurality of device100, each being coupled with device backs110of various thicknesses. Turning toFIG.20B, depicted therein is a top plan view of housing20being coupled with a plurality of device100, each being coupled with device backs110of various thicknesses. Turning toFIG.20C, depicted therein is a top plan view of housing20being coupled with a plurality of device100, each being coupled with device backs110of various thicknesses. Turning toFIG.21, depicted therein is a side elevational cross-sectional view of a rear portion of housing20with curvilinearly formed semi-rigid sheet assembly14of holder assembly10holding device back110aincluding back surface110a1combined to have thickness dimension T1. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is shown in the first position ofFIG.13accordingly taken along the21-21cutline ofFIG.20A. Turning toFIG.22, depicted therein is a top plan view of the rear portion shown inFIG.21of housing20coupled with the with one of the plurality of device100with width dimension W2accommodated by side assembly16and side assembly18of holder assembly10and including device back110acombined to have thickness dimension T1with curvilinearly formed semi-rigid sheet assembly14in the first position ofFIG.13to accommodate thickness dimension T1. Turning toFIG.23, depicted therein is a side elevational cross-sectional view of a front portion of housing20with curvilinearly formed semi-rigid sheet assembly14of holder assembly10holding device back110fincluding device backs110combined to have thickness dimension T2. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is shown in the second position ofFIG.17to accommodate thickness dimension T2taken along the23-23cutline ofFIG.20B. Turning toFIG.24, depicted therein is a side elevational cross-sectional view of a mid portion of housing20with curvilinearly formed semi-rigid sheet assembly14of holder assembly10holding device back110bincluding device backs110combined to have thickness dimension T3. Depicted implementation of curvilinearly formed semi-rigid sheet assembly14is shown in the third position ofFIG.18to accommodate thickness dimension T3taken along the24-24cutline ofFIG.20C. Turning toFIG.25, depicted therein is a left bottom rear perspective view of multiple instances of holder assembly10being uncoupled. As depicted, side portion12cof container assembly12includes threaded fastener12c3band threaded fastener12c4b. Turning toFIG.26, depicted therein is a left top front perspective view of multiple instances of holder assembly10being uncoupled. Turning toFIG.27, depicted therein is a left top front perspective view multiple instances of holder assembly10being uncoupled. Turning toFIG.28, depicted therein is a side elevational view of multiple instances of holder assembly10ofFIG.1. Turning toFIG.29, depicted therein is a left top front perspective exploded view of housing20with multiple instances of holder assembly10. As depicted, base portion20gof housing20includes side20g1, side20g2, side20g3, side20g4, aperture20g5, fastener cover20g7, and electronics20g8. Turning toFIG.30, depicted therein is a left bottom rear perspective exploded view of housing20with multiple instances of holder assembly10. As depicted, upper surface20fof housing20includes aperture20f1. Turning toFIG.31, depicted therein is a bottom plan view of housing20coupled with multiple instances of holder assembly10and with base portion20gremoved. Turning toFIG.32, depicted therein is a left bottom rear perspective view of housing20coupled with multiple instances of holder assembly10and with base portion20gremoved. Turning toFIG.33, depicted therein is a left bottom rear perspective exploded view of housing20including base portion20g. Turning toFIG.34, depicted therein is a bottom plan view of holder assembly and housing20with base portion20g. Turning toFIG.35, depicted therein is a left top front perspective view of housing20as also shown inFIG.12. Turning toFIG.36, depicted therein is a left top front perspective view of holder assembly10and housing20with base portion20g. Turning toFIG.37, depicted therein is a bottom plan view of housing20. Turning toFIG.38, depicted therein is a cross-sectional side elevational view of multiple of holder assembly10uncoupled from rear portion of housing20. Turning toFIG.39, depicted therein is a cross-sectional side elevational view of multiple instances of holder assembly10uncoupled from rear portion of housing20. Turning toFIG.40, depicted therein is a cross-sectional side elevational view of multiple instances of holder assembly10coupled from rear portion of housing20. As shown protrusion apertures of side portion12aand side portion12cbeing aligned with apertures of housing20in which protrusion apertures of side portion12aare also aligned with protrusion apertures of side portion12cwhen multiple instances of holder assembly10are coupled with housing20. In other implementations, other types of location points of multiple instances of holder assembly10and of housing20could be used instead of apertures. Turning toFIG.41, depicted therein is a cross-sectional side perspective view of multiple instances of holder assembly10coupled from rear portion of housing20. While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.” With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise. | 24,070 |
11863003 | DETAILED DESCRIPTION Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. However, the present disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Meanwhile, in the following description, with respect to constituent elements used in the following description, the suffixes “module” and “unit” are used or combined with each other only in consideration of ease in preparation of the specification, and do not have or indicate mutually different meanings. Accordingly, the suffixes “module” and “unit” may be used interchangeably. FIG.1is a view showing a power converting system according to an embodiment of the present disclosure. Referring to the drawings, a power converting system10according to an embodiment of the present disclosure may include at least one power generation device30, an energy storage apparatus100, and the like. The power converting system10according to an embodiment of the present disclosure may further include one or more of a load70or a grid90that receive power from the energy storage apparatus100. The load70is a device or component that consumes power of the power converting system10and may be located relatively close to the power converting system10(e.g., in the same building). For example, the load70may include a refrigerator, a washing machine, an air conditioner, a TV, a robot cleaner, a home appliance such as a robot, or a mobile electronic device such as a vehicle or a drone. The power generation device30may include, for example, a photovoltaic (PV) device that outputs DC voltage that is generated using solar power. However, the power converting system10may include a different type of power generation device30or may include multiple different types of power generation devices30. For example, power generation device30may be at least one of the PV device, a wind power generation device (or windmill) that outputs DC voltage using wind power, a hydraulic power generation device that outputs DC voltage using water movement, a tidal power generation device that outputs DC voltage using tidal flow, or a thermal power generation device that outputs DC voltage using heat such as geothermal heat. Hereinafter, the power generation device30is mainly described as a photovoltaic device for convenience of explanation. The energy storage apparatus100may store external power, such as to a battery or other power storage device, and then output power to the outside (e.g., to load70and/or grid90). For example, the energy storage apparatus100may receive DC voltage or alternating current (AC) voltage from the outside, store it in a battery, etc., and then output DC voltage or AC voltage to the outside. Meanwhile, since the battery205mainly stores DC voltage, the energy storage apparatus100mainly may receive DC voltage from at least one DC voltage source, store it in the battery205, and convert the stored DC voltage in the battery205into AC voltage and supply to the grid90or the load70. At this time, the power converting device200in the energy storage apparatus100may receive DC voltage from the outside or DC voltage from the battery205, perform power conversion, and charge the battery205or supply DC voltage stored in the battery205to the grid90or the load70, according to the power conversion. In particular, when DC voltage is input from a plurality of DC voltage sources to the power converting device200in the energy storage apparatus100, if a separate switching module in the power converting device is used for each power conversion, there may be problems such as an increase in the size and cost of the power converting device. Accordingly, the present disclosure provides a power converting device200that can commonly operate in a power generation mode of the power generation device30, a charging mode of the battery205, and the like using a single switching module. To this end, the power converting device200may include a first input terminal T1configured to receive a first DC voltage from the battery205, and a second input terminal T2configured to receive a second DC voltage from the power generation device30. The power converting device200may further include a switching module (also referred to herein as insulated bipolar transistors or IBT) that includes a plurality of upper arm switching elements (or first switches) Qa, Qb and a plurality of lower arm switching elements (or second switches) Q′a, Q′b, and outputs direct current (DC) power to the DC link (a-b terminal) (or DC terminal) by switching the first or second direct current power and a DC link capacitor C disposed at the DC link (a-b terminal). At least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may operate in a power generation mode of receiving power from the power generation device30, and at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT may operate in a charging mode of the battery205. Accordingly, it is possible to operate the common switching module IBT even for a plurality of DC voltage sources. In addition, it is possible to implement the compact power converting device200in a plurality of DC voltage sources. Meanwhile, the switching module IBT may further operate in the power generation mode of the power generation device30, in the charging mode of the battery205, in the discharging mode of the battery205, or in the grid charging mode. Accordingly, since the common switching module IBT may be operated even for a plurality of DC voltage sources, a compact power converting device200can be implemented. FIGS.2A and2Bare views showing a power converting device related to the present disclosure. Referring to the drawings, a power converting device200xrelated to the present disclosure may receive DC voltage from the battery205or DC voltage from the power generation device30(such as a PV device). That is, DC voltage may be respectively input into power converting device200xfrom two DC voltage sources. The power converting device200xincludes a first switching module IBTa for power conversion of the DC voltage from the battery205, and a second switching module IBTb for power conversion of the DC voltage from the power generation device30. For example, the first switching module IBTa operates in the discharging mode or charging mode of the battery205, and the second switching module IBTb operates in the power generation mode of the power generation device30. In addition, the first switching module IBTa operates in the grid charging mode in which power is output from power converting device200x. FIG.2Bis a schematic view of the size of the power converting device ofFIG.2A. Referring to the drawing, since the circuit board PCBx of the power converting device200xincludes a first switching module IBTa, a second switching module IBTb, and an inverter540, the width is approximately wx (reflecting a combination of a first width of the first switching module IBTa, a second width of the second switching module IBTb and the third width of the inverter540), and the height is approximately hx. In this way, when the power converting device200xis provided with the first switching module IBTa and the second switching module IBTb corresponding to the number of input DC voltage sources, the size of the power converting device200xbecomes large, and a failure of any one of the switching modules module IBTa and IBTb causes the entire power converting device to not operate, resulting in a deterioration in durability. Accordingly, the present disclosure proposes a power converting device200that may commonly operate in a power generation mode of the power generation device30, a charging mode of the battery205, and the like using one switching module. This power converting device configuration will be described with reference toFIG.3A. FIG.3Ais a view showing a power converting device according to an embodiment of the present disclosure. First, referring toFIG.3A, a power converting device200according to an embodiment of the present disclosure includes a first input terminal T1configured to receive a first DC voltage from a battery205and a second input terminal T2configured to receive a second DC voltage of a power generation device30, a switching module IBT including a plurality of upper arm switching elements (or first switching elements) Qa, Qb and a plurality of lower arm switching elements (or second switching elements) Q′a, Q′b, and configured to switch between the first DC voltage or the second DC voltage, to output DC voltage to the DC link (a-b terminal), and a DC link capacitor C disposed at the DC link (a-b terminal). In the power converting device200according to the embodiment of the present disclosure, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may operate in the power generation mode of the power generation device30, and at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT may operate in the charging mode of the battery205. Accordingly, it is possible to operate the common switching module IBT even for a plurality of DC voltage sources. In addition, it is possible to implement the compact power converting device200in a plurality of DC voltage sources. Meanwhile, the power converting device200according to an embodiment of the present disclosure may further include a first relay element (or first relay switch) R1disposed between the first input terminal T1and the switching module IBT, and a second relay element (or second relay switch) R2disposed between second input terminal T2and the switching module IBT. While the drawings show a single battery205connected to the power converting device200, it is should be appreciated that multiple batteries205may be connected to the power converting device200, and the power converting device200may include multiple first input terminals T1electrically coupled to respective first relay elements R1. Similarly, while the drawings show a single power generation device30connected to the power converting device200, it is should be appreciated that multiple power generation devices30may be connected to the power converting device200, and the power converting device200may include multiple second input terminals T2electrically coupled to respective second relay elements R2. Meanwhile, the switching module IBT may include first and second upper arm switching elements Qa and Qb connected in parallel between a first node n1and a second node n2, and first and second lower arm switching elements Q′a and Q′b connected in parallel between a third node n3and a fourth nodes n4. The operations of first and second upper arm switching elements Qa and Qb and first and second lower arm switching elements Q′a and Q′b with respect to first-fourth nodes n1-n4are discussed in greater detail below. One end of the first and second relay elements R2may be commonly connected to a third node n3in the switching module IBT. Meanwhile, the power converting device200according to an embodiment of the present disclosure may further include a first inductor L1disposed between the first input terminal T1and the second node n2, and a second inductor L2disposed between a second input terminal T2and the third node n3. The power converting device200may further include a first diode D1disposed between the second node n2and ground GND, and a second diode D2disposed between a third node n3and one end of the DC link capacitor C. Meanwhile, the power converting device200according to an embodiment of the present disclosure may further include a bidirectional inverter (also referred as a DC/AC inverter)540configured to convert the DC voltage of the DC link (a-b terminal) into AC voltage and output the converted AC voltage. The inverter540may further convert external AC voltage into DC voltage, such as to provide charging power to the battery205. Meanwhile, the power converting device200according to an embodiment of the present disclosure may further include a controller570configured to control a switching module IBT and/or the bidirectional inverter540. For example, the controller570may further control the first relay element R1and the second relay element R2. Meanwhile, when controller570causes the first relay element R1to be turned off and the second relay element R2to be turned on, the DC voltage converted through the second relay element R2and the third node n3output to the DC link capacitor C, or the DC voltage stored in the DC link capacitor C is charged into the battery205through the first node n1. Accordingly, it is possible to perform a discharging mode or a charging mode of the battery205by using the compact power converting device200. Meanwhile, the controller570may control at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT to operate in the power generation mode of the power generation device30, and at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT to operate in the charging mode of the battery205. For example, the controller570may control at least some of the plurality of upper arm switching elements Qa, Qb of the switching module IBT or at least some of a plurality of lower arm switching elements Q′a, Q′b of the switching module IBT to operate in the discharging mode of the battery205. Accordingly, it is possible to operate the common switching module IBT even for a plurality of DC voltage sources. The controller570may similarly control at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT to operate in the grid charging mode or the charging mode of the battery205. Meanwhile, the controller570may control the switching module IBT to be operated in the power generation mode of the power generation device30, the charging mode of the battery205, the discharging mode of the battery205, or the grid charging mode. Accordingly, since the common switching module IBT may be operated even for a plurality of DC voltage sources, a compact power converting device200can be implemented. FIG.3Bis a view schematically showing the size of the power converting device ofFIG.3A. Referring to the drawings, in contrast theFIG.2A, a circuit board PCB of the power converting device200includes only one switching module IBT. That is, the circuit board PCB of the power converting device200includes one switching module IBT and an inverter540. Accordingly, the width is approximately wa (reflecting, for example, a combination of a first width of the IBT200and a second width of the DC/AC inverter5400, and the height is approximately ha. That is, the width Wa of the circuit board PCB of the power converting device200ofFIG.3Bmay be smaller than the width wx ofFIG.2B. Therefore, it is possible to implement a compact power converting device. FIGS.4to10are views referenced for description of the power converting device ofFIG.3A. First,FIG.4is a table showing a different operation modes of the power converting device200according to the operation of the first relay element R1and the second relay element R2. The operation modes may include a power generation mode, a charging mode, a discharging mode, a disable mode, and the like, and these modes will be described in more detail with reference toFIG.6below. Referring to the drawings, when the controller570causes the first relay element R1and the second relay element R2to both be turned off concurrently, a standby mode is performed. The standby mode is described in greater detail below. Next, when the first relay element R1is turned off and the second relay element R2is turned on, DC voltage from the power generation device30is input to the switching module IBT, and accordingly, a power generation (or PV) mode or a charging mode may be performed. That is, when the power generation device30is electrically connected via the second relay element R2to the switching module IBT, the DC voltage from the power generation device30may be directed through the third node n3in the switching module IBT, and may be stored in the DC link capacitor C. In the power generation mode, the inverter540operates in the forward direction to convert stored power from the DC link capacitor C, and the converted power may be outputted, through the inverter540, to load70or the grid90. Meanwhile, when the inverter540is not operated while the first relay element R1is turned off and the second relay element R2is turned on, a battery charging mode may be performed, and in the battery charging mode, the voltage stored in the DC link capacitor C (e.g., from the power generation device30) is directed to the battery205through the first node n1in the switching module IBT. Next, when the first relay element R1is turned on and the second relay element R2is turned off, a battery discharging mode is performed, in which the battery205is electrically connected via the first relay element R1to the switching module IBT so that the voltage stored in the battery205is output through the third node n3in the switching module IBT to the DC link capacitor C. The inverter540may then operate to convert stored power from the DC link capacitor C, and the converted power may be outputted to load70or the grid90. Meanwhile, if both the first relay element R1and the second relay element R2are concurrently turned on by the controller570, there is a possibility of a short occurring between the battery205and the power generation device30(e.g., such that power bypasses the switching module IBT). In this condition, the power device200should enter a disabled state. FIG.5is a flow chart illustrating a method of operating a power converting device according to an embodiment of the present disclosure. Referring to the drawings, the first relay element R1in the power converting device200is turned off, and the second relay element R2is turned off (S510). Accordingly, the standby mode is performed. At this time, the power converting device200detects the level of the DC voltage from the power generation device30(S515). For example, a voltage detector in the power converting device200may be disposed between the second input terminal T2(e.g., a terminal between the power converting device200and the power generation device30) and the second inductor L2ofFIG.3A. Meanwhile, the voltage detected by the voltage detector (not shown) in the power converting device200may be input to the controller570. In another example, the power converting device200may be configured to provide an electrical path from a point between the second input terminal T2and the second inductor L2to the controller570, and the controller570may evaluate a voltage via this path. The controller570determines whether the voltage from the power generation device30is within a predetermined range (S520). Here, the predetermined range may correspond to a normal operating range of the power generation device30(e.g., the power generation device30is operating to generate a desired range of DC voltages). Meanwhile, when the voltage from the power generation device30is within the predetermined range, the controller570turns off the first relay element R1and turns on the second relay element R2so that the power generation mode and/or the charging mode is performed (S525). In one example, when performing the power generation mode, the controller570may further control, in addition to turning off the first relay element R1and turning on the second relay element R2, the lower arm switching of the switching module IBT such that at least some of the elements Q′a and Q′b to operate to direct DC power from the power generation device30to the DC link capacitor C. Accordingly, the second DC voltage from the power generation device30is boosted, so that the boosted DC voltage may be output to the DC link capacitor C. Meanwhile, when the voltage detected by the voltage detector (not shown) is out of a predetermined range in step S520(e.g., insufficient power is generated by the power generation device30of a PV device when light from the sun is blocked), the controller570may control the first relay element R1to be turned on and the second relay element R2to be turned off so that the discharging mode, etc. is performed (S530). Accordingly, the battery discharging mode is performed, and the voltage stored in the battery205may be output to the DC link capacitor C through the third node n3in the switching module IBT. FIGS.6to10are views referred to for explanation of various modes of the power converting device. First,FIG.6is a view showing an initial charging mode of a DC link capacitor of the power converting device200. Referring to the drawing, the controller570may control the first relay element R1to be turned on and the second relay element R2to be turned off (e.g., the discharging mode). When the first relay element R1is turned on and the second relay element R2is turned off, the first DC voltage of the battery205is transferred to the DC link capacitor C through the first inductor L1, the first relay element R1, the third node n3, and the second diode D2according to the current path of Ipath1. Therefore, initial charging of the DC link capacitor C may be performed via power received from the battery230. In this case, the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may not operate. Thus, path Ipath1may bypass the lower arm switching elements Q′a and Q′b. Alternatively, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may perform switching operations (turn-on and turn-off operations). In this case, the first inductor L1, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT, and the second diode D2may operate as a boost converter. For example, DC power from the battery230may be directed in a boost path via lower arm switching elements Q′a and Q′b. Accordingly, the boosted voltage from the battery230and the lower arm switching elements Q′a and Q′b may be transferred to the DC link capacitor C. Next,FIG.7is a view showing a power generation mode of the power converting device200. Referring to the drawing, the controller570may control the first relay element R1to be turned off and the second relay element R2to be turned on. When the first relay element R1is turned off and the second relay element R2is turned on, the second DC voltage of the power generation device30is transmitted to the DC link capacitor C through the second inductor L2, the second relay element R2, the third node n3, and the second diode D2, according to the current path of Ipath2. In this case, when the inverter540operates in the forward direction, the DC voltage of the DC link capacitor C may be converted to AC voltage and supplied to the grid90or the load70. That is, according to the power generation mode of the power generation device30, the DC voltage of the power generation device30may be converted by the power converting device200, and the converted power may be output to the outside through the DC link capacitor C and the inverter540. Meanwhile, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may perform switching operations (turn-on and turn-off operations) in a state in which the first relay element R1is turned off and the second relay element R2is turned on (e.g., in the power generation mode). In this case, the second inductor L2, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT, and the second diode D2may operate as a boost converter. Accordingly, the boosted voltage from power generation device30may be transferred to the DC link capacitor C. Next,FIG.8is a view illustrating a battery charging mode of the power converting device200. Referring to the drawing, the controller570may control the first relay element R1to be turned off and the second relay element R2to be turned on. As previously described with respect toFIG.7, when the first relay element R1is turned off and the second relay element R2is turned on, in accordance with the current path of Ipath2, the second DC voltage the power generation device30is transmitted to the DC link capacitor C through the second inductor L2, the second relay element R2, the third node n3, and the second diode D2. In this case, when the inverter540operates in the forward direction, the DC voltage of the DC link capacitor C may be converted to AC voltage and supplied to the grid90or the load70. That is, according to the power generation mode of the power generation device30, the DC voltage of the power generation device30may be converted by the power converting device200and outputted through the DC link capacitor C and the inverter540. Meanwhile, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may perform switching operations (turn-on and turn-off operations) in a state in which the first relay element R1is turned off and the second relay element R2is turned on (e.g., power from power generation device30is provided to the DC link capacitor C). In this case, the second inductor L2, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT, and the second diode D2may operate as a boost converter. Accordingly, the boosted voltage from power generation device30may be transferred to the DC link capacitor C. Meanwhile, when the first relay element R1is turned off and the second relay element R2is turned on, the DC voltage stored in the DC link capacitor C may also be supplied to the battery205through the first node n1of the switching module IBT and the first inductor L1, according to the current path of Ipath3during the charging mode. For example, at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT are performing switching operations (e.g., turn-on and turn-off operations) while the first relay element R1is turned off and the second relay element R2is turned on. In this case, at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT, the first inductor L1, and the first diode D1may operate as a buck converter, and accordingly, a stepped down voltage may be supplied to the battery205. Next,FIG.9is a view illustrating a battery discharging mode of the power converting device200. Referring to the drawing, the controller570may control the first relay element R1to be turned on and the second relay element R2to be turned off. When the inverter540operates in the forward direction in a state in which the first relay element R1is turned on and the second relay element R2is turned off, the first DC voltage of the battery205is converted to AC voltage through the first inductor L1, the first relay element R1, the third node n3, the second diode D2, the DC link capacitor C, and the inverter450according to the current path of Ipath4, the converted power may be supplied to the grid90or the load70. That is, according to the discharging mode of the battery205, the DC voltage of the battery205may be converted by the power converter200, and may be output to the outside through the DC link capacitor C and the inverter540. Meanwhile, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT may perform switching operations (turn-on and turn-off operations) in a state in which the first relay element R1is turned on and the second relay element R2is turned off. In this case, the second inductor L2, at least some of the plurality of lower arm switching elements Q′a and Q′b of the switching module IBT, and the second diode D2may operate as a boost converter. Accordingly, the boosted voltage may be transferred to the DC link capacitor C. Next,FIG.10is a view showing a grid charging mode of the power converting device200(e.g., AC power from the grid90is received and converted by the power converting device200to charge the battery205). Referring to the drawings, the controller570may control the inverter540to operate in a reverse direction in a state in which the first relay element R1is turned off and the second relay element R2is turned off (e.g., similar to the standby mode). For example, the controller570may control the grid charging mode to be performed when the voltage of the battery205is less than a reference value or in an emergency situation or when a voltage from power generation device30is less than a threshold value. When the inverter540operates in the reverse direction in a state in which the first relay element R1is turned off and the second relay element R2is turned off, the converted DC voltage from the grid90may be supplied to the battery205through the inverter540, the DC link capacitor C, the first node n1of the switching module IBT, and the first inductor L1according to the current path of Ipath5. That is, the AC voltage of the grid90is converted to DC voltage by the reverse operation of the inverter540, and the converted DC voltage may be supplied to the battery205through the DC link (a-b), the first node n1of the switching module IBT the first inductor L1. At this time, at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT may perform switching operations (turn-on and turn-off operations). In this case, at least some of the plurality of upper arm switching elements Qa and Qb of the switching module IBT, the first inductor L1, and the first diode D1may operate as a buck converter to step-down the DC link voltage, and accordingly, the stepped down voltage may be supplied to the battery205. As a result, comprehensively referring toFIGS.6to10, when the first relay element R1is turned off and the second relay element R2is turned on, the DC voltage converted through the second relay element R2, and the third node n3may be output to the DC link capacitor C, or the DC voltage stored in the DC link capacitor C may be charged into the battery205through the first node n1. Accordingly, it is possible to perform a discharging mode or a charging mode of the battery205by using the compact power converting device200. Meanwhile, when the first relay element R1is turned on and the second relay element R2is turned off, the DC voltage converted through the first relay element R1and the third node n3may be output to the DC link capacitor C. Accordingly, it is possible to operate the common switching module IBT even for a plurality of DC voltage sources. Meanwhile, when the first and second lower arm switching elements Q′a and Q′b respectively perform switching in a state in which the first relay element R1is turned on and the second relay element R2is turned off, the first DC voltage is boosted and the boosted voltage is output to the DC link capacitor C. Accordingly, it is possible to perform the discharging mode of the battery205by using the compact power converting device200. Meanwhile, when the first and second lower arm switching elements Q′a and Q′b respectively perform switching in a state in which the first relay element R1is turned off and the second relay element R2is turned on, the second DC voltage is boosted and the boosted voltage is output to the DC link capacitor C. Accordingly, it is possible to perform the power generation mode of the power generation device30by using the compact power converting device200. Meanwhile, when the first and second lower arm switching elements Q′a and Q′b are turned on, respectively, while the first relay element R1is turned off and the second relay element R2is turned on, energy is stored in the second inductor L2, and when the first and second lower arm switching elements Q′a and Q′b are turned off, respectively, the boosted voltage boosted based on the second DC voltage and the second the energy stored in inductor L2is output to the DC link capacitor C. Accordingly, it is possible to perform the power generation mode of the power generation device30by using the compact power converting device200. Meanwhile, when the first and second upper arm switching elements Qa and Qb respectively perform switching in a state in which the first relay element R1is turned off and the second relay element R2is turned on, the DC voltage stored in the DC link capacitor C is converted, and the converted DC voltage is output to the battery205. Accordingly, it is possible to perform the charging mode of the battery205by using the compact power converting device200. Meanwhile, when the first and second upper arm switching elements Qa and Qb are turned on, respectively, in a state in which the first relay element R1is turned off and the second relay element R2is turned on, energy is stored in the first inductor L1, and when the first and second upper arm switching elements Qa and Qb are turned off, respectively, a stepped down voltage based on the energy stored in the first inductor L1is transferred to the battery205is output. Accordingly, it is possible to perform the charging mode of the battery205by using the compact power converting device200. Meanwhile, when the first relay element R1is turned off, the second relay element R2is turned on, and the first and second upper arm switching elements Qa and Qb are turned on, respectively, in a state in which the bidirectional inverter540operates, the AC voltage from the external grid90is converted and the converted DC voltage is stored in the DC link (a-b terminal), energy is stored in the first inductor L1, and when the two upper arm switching elements Qa and Qb are turned off, respectively, a voltage reduced based on the energy stored in the first inductor L1is output to the battery205. Accordingly, it is possible to perform the grid charging mode by using the compact power converting device200. Meanwhile, the switching module IBT may all operate in the power generation mode of the power generation device30, in the charging mode of the battery205, in the discharging mode of the battery205, or in the grid charging mode. Accordingly, since the common switching module IBT may be operated even for a plurality of DC voltage sources, a compact power converting device200may be implemented. A power converting device and energy storage apparatus according to an embodiment of the present disclosure comprises a first input terminal configured to receive a first DC voltage from a battery, a second input terminal configured to receive a second DC voltage from a power generation device, a switching module including a plurality of upper arm switching elements and a plurality of lower arm switching elements, and configured to output DC voltage to a DC link by switching the first DC voltage or the second DC voltage, and a DC link capacitor disposed at the DC link, wherein at least some of the plurality of lower arm switching elements of the switching module operate in a power generation mode of the power generation device, and at least some of the plurality of upper arm switching elements of the switching module operate in a charging mode of the battery. Accordingly, a common switching module may be operated even for a plurality of DC voltage sources. In addition, it is possible to implement a compact power converting device for a plurality of DC voltage sources. Meanwhile, at least some of the plurality of upper arm switching elements of the switching module, or at least some of the plurality of lower arm switching elements of the switching module operate in a discharging mode of the battery. Accordingly, a common switching module may be operated even for a plurality of DC voltage sources. Meanwhile, a power converting device and energy storage apparatus according to an embodiment of the present disclosure further comprises a first relay element disposed between the first input terminal and the switching module, a second relay element disposed between the second input terminal and the switching module. Accordingly, a common switching module may be operated even for a plurality of DC voltage sources. Meanwhile, the switching module comprises first and second upper arm switching elements connected in parallel between a first node and a second node, first and second lower arm switching elements connected in parallel between a third node and a fourth node, and one ends of the first and second relay elements are commonly connected to the third node in the switching module, when the first relay element is turned off and the second relay element is turned on, a DC voltage converted through the second relay element and the third node is output to the DC link capacitor, or a DC voltage stored in the DC link capacitor, through the first node, charges the battery. Accordingly, it is possible to perform a discharging mode or a charging mode of the battery using a compact power converting device. Meanwhile, when the first relay element is turned on and the second relay element is turned off, a DC voltage converted through the first relay element and the third node is output to the DC link capacitor. Accordingly, a common switching module may be operated even for a plurality of DC voltage sources. Meanwhile, a power converting device and energy storage apparatus according to an embodiment of the present disclosure further comprises a first inductor disposed between the first input terminal and the second node, a second inductor disposed between the second input terminal and the third node, a first diode disposed between the second node and a ground; and a second diode disposed between the third node and one end of the DC link capacitor. Accordingly, a common switching module may be operated even for a plurality of DC voltage sources. Meanwhile, when the first and second lower arm switching elements each perform switching in a state in which the first relay element is turned on and the second relay element is turned off, a voltage boosted by boosting the first DC voltage is output to the DC link capacitor. Accordingly, a common switching module may be operated even for a plurality of DC voltage sources. Meanwhile, when the first and second lower arm switching elements each perform switching in a state in which the first relay element is turned off and the second relay element is turned on, a voltage boosted by boosting the second DC voltage is output to the DC link capacitor. Accordingly, it is possible to perform a power generation mode of a power generation device using a compact power converting device. Meanwhile, when the first and second lower arm switching elements are turned on and the second relay element is turned on in a state in which the first relay element is turned off respectively, energy is stored in the second inductor, and when the first and second lower arm switching elements are turned off respectively, a boosted voltage by boosting based on the second DC voltage and energy stored in the second inductor is output to the DC link capacitor. Accordingly, it is possible to perform a power generation mode of a power generation device using a compact power converting device. Meanwhile, when the first and second upper arm switching elements each perform switching in a state in which the first relay element is turned off and the second relay element is turned on, DC voltage stored in the DC link capacitor is converted, and the converted DC voltage is output to the battery. Accordingly, it is possible to perform a charging mode of the battery using a compact power converting device. Meanwhile, when the first and second upper arm switching elements are turned on and the second relay element is turned on in a state in which the first relay element is turned off respectively, energy is stored in the first inductor, and when the first and second upper arm switching elements are turned off respectively, a voltage stepped down based on energy stored in the first inductor is output to the battery. Accordingly, it is possible to perform a charging mode of the battery using a compact power converting device. Meanwhile, a power converting device and energy storage apparatus according to an embodiment of the present disclosure further comprises a bidirectional inverter configured to convert and output the DC voltage of the DC link into AC voltage or to convert external AC voltage to DC voltage. Accordingly, since a common switching module may be operated even for a plurality of DC voltage sources, it is possible to implement a compact power converting device. Meanwhile, at least some of the plurality of upper arm switching elements of the switching module are operated in a grid charging mode or the charging mode of the battery. Accordingly, since a common switching module may be operated even for a plurality of DC voltage sources, it is possible to implement a compact power converting device. Meanwhile, in a state in which the bidirectional inverter is operated, AC voltage from an external grid is converted and the converted DC voltage is stored in the DC terminal, the first relay element is turned off, and the second relay element is turned on, when the first and second upper arm switching elements are turned on respectively, energy is stored in the first inductor, and when the first and second upper arm switching elements are turned off respectively, a voltage stepped down based on energy stored in the first inductor is output to the battery. Accordingly, it is possible to perform a grid discharging mode or a charging mode of the battery using a compact power converting device. Meanwhile, the switching modules are operated in the power generation mode of the power generation device, in the charging mode of the battery, in a discharging mode of the battery, or in a grid charging mode. Accordingly, since a common switching module may be operated even for a plurality of DC voltage sources, it is possible to implement a compact power converting device. A power converting device according to another embodiment of the present disclosure comprises a first input terminal configured to receive a first DC voltage from the battery, a second input terminal configured to receive a second DC voltage from a power generation device, a switching module including a plurality of upper arm switching elements and a plurality of lower arm switching elements, and configured to output DC voltage to a DC link by switching the first DC voltage or the second DC voltage, and, a DC link capacitor disposed at the DC link, wherein at least some of the plurality of upper arm switching elements of the switching module operate in a grid charging mode. Accordingly, since a common switching module may be operated even for a plurality of DC voltage sources, it is possible to implement a compact power converting device. The power converting device and the energy storage apparatus including the same according to an embodiment of the present disclosure are not limited to the configuration and method of the embodiments described above, but the above embodiments may be configured by selectively combining all or part of each of the embodiments so that various modifications can be achieved. As aspect of the present disclosure provides a power converting device capable of operating a common switching module even for multiple DC voltage sources, and energy storage apparatus including the same. Another aspect of the present disclosure provides a compact power converting device for a plurality of DC voltage sources, and energy storage apparatus including the same. A power converting device and energy storage apparatus according to an embodiment of the present disclosure comprises a first input terminal configured to receive a first DC voltage from a battery, a second input terminal configured to receive a second DC voltage from a power generation device, a switching module including a plurality of upper arm switching elements and a plurality of lower arm switching elements, and configured to output DC voltage to a DC link by switching the first DC voltage or the second DC voltage, and, a DC link capacitor disposed at the DC link, wherein at least some of the plurality of lower arm switching elements of the switching module operate in a power generation mode of the power generation device, and at least some of the plurality of upper arm switching elements of the switching module operate in a charging mode of the battery. Meanwhile, at least some of the plurality of upper arm switching elements of the switching module, or at least some of the plurality of lower arm switching elements of the switching module operate in a discharging mode of the battery. Meanwhile, a power converting device and energy storage apparatus according to an embodiment of the present disclosure further comprises a first relay element disposed between the first input terminal and the switching module, a second relay element disposed between the second input terminal and the switching module. Meanwhile, the switching module comprises first and second upper arm switching elements connected in parallel between a first node and a second node, first and second lower arm switching elements connected in parallel between a third node and a fourth node, and one ends of the first and second relay elements are commonly connected to the third node in the switching module, when the first relay element is turned off and the second relay element is turned on, a DC voltage converted through the second relay element and the third node is output to the DC link capacitor, or a DC voltage stored in the DC link capacitor, through the first node, charges the battery. Meanwhile, when the first relay element is turned on and the second relay element is turned off, a DC voltage converted through the first relay element and the third node is output to the DC link capacitor. Meanwhile, a power converting device and energy storage apparatus according to an embodiment of the present disclosure further comprises a first inductor disposed between the first input terminal and the second node, a second inductor disposed between the second input terminal and the third node, a first diode disposed between the second node and a ground; and a second diode disposed between the third node and one end of the DC link capacitor. Meanwhile, when the first and second lower arm switching elements each perform switching in a state in which the first relay element is turned on and the second relay element is turned off, a voltage boosted by boosting the first DC voltage is output to the DC link capacitor. Meanwhile, when the first and second lower arm switching elements each perform switching in a state in which the first relay element is turned off and the second relay element is turned on, a voltage boosted by boosting the second DC voltage is output to the DC link capacitor. Meanwhile, when the first and second lower arm switching elements are turned on and the second relay element is turned on in a state in which the first relay element is turned off respectively, energy is stored in the second inductor, and when the first and second lower arm switching elements are turned off respectively, a boosted voltage by boosting based on the second DC voltage and energy stored in the second inductor is output to the DC link capacitor. Meanwhile, when the first and second upper arm switching elements each perform switching in a state in which the first relay element is turned off and the second relay element is turned on, DC voltage stored in the DC link capacitor is converted, and the converted DC voltage is output to the battery. Meanwhile, when the first and second upper arm switching elements are turned on and the second relay element is turned on in a state in which the first relay element is turned off respectively, energy is stored in the first inductor, and when the first and second upper arm switching elements are turned off respectively, a voltage stepped down based on energy stored in the first inductor is output to the battery. Meanwhile, a power converting device and energy storage apparatus according to an embodiment of the present disclosure further comprises a bidirectional inverter configured to convert and output the DC voltage of the DC link into AC voltage, or converts external AC voltage to DC voltage. Meanwhile, at least some of the plurality of upper arm switching elements of the switching module are operated in a grid charging mode or the charging mode of the battery. Meanwhile, in a state in which the bidirectional inverter is operated, AC voltage from an external grid is converted and the converted DC voltage is stored in the DC terminal, the first relay element is turned off, and the second relay element is turned on, when the first and second upper arm switching elements are turned on respectively, energy is stored in the first inductor, and when the first and second upper arm switching elements are turned off respectively, a voltage stepped down based on energy stored in the first inductor is output to the battery. Meanwhile, the switching modules are operated in the power generation mode of the power generation device, in the charging mode of the battery, in a discharging mode of the battery, or in a grid charging mode. A power converting device according to another embodiment of the present disclosure comprises a first input terminal configured to receive a first DC voltage from the battery, a second input terminal configured to receive a second DC voltage from a power generation device, a switching module including a plurality of upper arm switching elements and a plurality of lower arm switching elements, and configured to output DC voltage to a DC link by switching the first DC voltage or the second DC voltage, and a DC link capacitor disposed at the DC link, wherein at least some of the plurality of upper arm switching elements of the switching module operate in a grid charging mode. It will be understood that when an element or layer is referred to as being “on” another element or layer, the element or layer can be directly on another element or layer or intervening elements or layers. In contrast, when an element is referred to as being “directly on” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. Spatially relative terms, such as “lower”, “upper” and the like, may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “lower” relative to other elements or features would then be oriented “upper” relative to the other elements or features. Thus, the exemplary term “lower” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Embodiments of the disclosure are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the disclosure. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the disclosure should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. | 55,246 |
11863004 | The appended drawings are not necessarily to scale, and may present a somewhat simplified representation of various preferred features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes. Details associated with such features will be determined in part by the particular intended application and use environment. DETAILED DESCRIPTION The present disclosure is susceptible of embodiment in many different forms. Representative examples of the disclosure are shown in the drawings and described herein in detail as non-limiting examples of the disclosed principles. To that end, elements and limitations described in the Abstract, Introduction, Summary, and Detailed Description sections, but not explicitly set forth in the claims, should not be incorporated into the claims, singly or collectively, by implication, inference, or otherwise. For purposes of the present description, unless specifically disclaimed, use of the singular includes the plural and vice versa, the terms “and” and “or” shall be both conjunctive and disjunctive, and the words “including”, “containing”, “comprising”, “having”, and the like shall mean “including without limitation”. Moreover, words of approximation such as “about”, “almost”, “substantially”, “generally”, “approximately”, etc., may be used herein in the sense of “at, near, or nearly at”, or “within 0-5% of”, or “within acceptable manufacturing tolerances”, or logical combinations thereof. As used herein, a component that is “configured to” perform a specified function is capable of performing the specified function without alteration, rather than merely having potential to perform the specified function after further modification. In other words, the described hardware, when expressly configured to perform the specified function, is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the specified function. Referring to the drawings, wherein like reference numbers refer to like features throughout the several views,FIG.1depicts an electrified powertrain system10having a split-phase bidirectional onboard charger (OBC)25constructed in accordance with the present disclosure. An exemplary embodiment of the OBC25is depicted inFIG.2and described in further detail below with reference toFIGS.2and3. Use of the described OBC25allows for the selective delivery of a split-phase alternating current (AC) voltage output during vehicle-to-load (V2L) or vehicle-to-grid (V2G) operations—collectively referred to as vehicle-to-anything (V2X)—while at the same time retaining the capability of providing a single-phase AC voltage output. The solutions set forth herein are intended to provide such capabilities with a corresponding reduction in mass and required packaging space, thus facilitating integration with the electrified powertrain system10ofFIG.1, and with its particular host system. With respect to such a host system, the electrified powertrain system10may be used as part of a motor vehicle11or another mobile system. As shown, the motor vehicle11exemplified inFIG.1(also see the motor vehicle11A ofFIG.4) may be equipped as a battery electric vehicle, with the present teachings also being extendable to plug-in hybrid electric vehicles. Alternatively, the electrified powertrain system10may be used as part of another mobile system such as but not limited to a rail vehicle, aircraft, marine vessel, robot, farm equipment, etc. Likewise, the electrified powertrain system10may be stationary, such as in the case of a powerplant, hoist, drive belt, or conveyor system. Therefore, the electrified powertrain system10in the representative vehicular embodiment ofFIGS.1and4is intended to be illustrative of the present teachings and not limiting thereof. The motor vehicle11shown inFIG.1includes a vehicle body12and road wheels14F and14R, with “F” and “R” indicating the respective front and rear positions. The road wheels14F and14R rotate about respective axes15and150, with the road wheels14F, the road wheels14R, or both being powered by output torque (arrow TO) from a rotary electric machine (ME)16of the electrified powertrain system10as indicated by arrow [14]. The road wheels14F an14R thus represent a mechanical load in this embodiment, with other possible mechanical loads being possible in different host systems. To that end, the electrified powertrain system10includes a power inverter module (PIM)18and a high-voltage battery pack (BHV)20, e.g., a multi-cell lithium-ion propulsion battery or a battery having another application-suitable chemistry, both of which are arranged on a high-voltage DC bus22. As appreciated in the art, the PIM18includes a DC side180and an alternating current (AC) side280, with the latter being connected to individual phase windings (not shown) of the rotary electric machine16when the rotary electric machine16is configured as a polyphase rotary electric machine in the form of a propulsion or traction motor as shown. The battery pack20in turn is connected to the DC side180of the PIM18as shown, such that a battery voltage from the battery pack20is provided to the PIM18during propulsion modes of the motor vehicle11. The PIM18, or more precisely a set of semiconductor switches (not shown) residing therein, are controlled via pulse width modulation, pulse density modulation, or other suitable switching control techniques to invert a DC input voltage on the DC bus22into an AC output voltage suitable for energizing a high-voltage AC bus220. High-speed switching of the resident semiconductor switches of the PIM18thus ultimately energizes the rotary electric machine16to thereby cause the rotary electric machine16to deliver the output torque (arrow TO) as a motor drive torque to one or more of the road wheels14F and/or14R in the illustrated embodiment ofFIG.1, or to another coupled mechanical load in other implementations. Electrical components of the electrified powertrain system10may also include an accessory power module (APM)24and an auxiliary battery (BAUX)26. The APM24is configured as a DC-DC converter that is connected to the DC bus22, as appreciated in the art. In operation, the APM24is capable, via internal switching and voltage transformation, of reducing a voltage level on the DC bus22to a lower level suitable for charging the auxiliary battery26and/or supplying low-voltage power to one or more accessories (not shown) such as lights, displays, etc. Thus, “high-voltage” refers to voltage levels well in excess of typical 12-15 V low/auxiliary voltage levels, with 400 V or more being an exemplary high-voltage level in some embodiments of the battery pack20. The OBC25shown inFIG.1is selectively connectable to an offboard charging station28via input/output (I/O) coupling points29during a charging mode during which the battery pack20is recharged by an AC charging voltage (VCH) from the offboard charging station28. The I/O coupling points29may include an output connector(s)290A that is electrically connected to the switchgear block30and connectable to the external AC electrical load140during the discharging mode of the OBC25. Additionally, the I/O outlets29may include an input connector(s)290B electrically connected to the switchgear block30and connectable to a charging port13. For instance, a charging cable28C may be connected to the charging port13located on the vehicle body12, e.g., via an SAE J1772 connection. The input connector290B in such an embodiment is thus configured to receive AC power from a corresponding J1772 charging plug (not shown). The electrified powertrain system10may also be configured to selectively receive a DC charging voltage in one or more embodiments as appreciated in the art, in which case the OBC25would be selectively bypassed using circuitry (not shown) that is not otherwise germane to the present disclosure. For the purposes of the present disclosure, the OBC25operates in different modes: (1) a charging mode during which the OBC25receives the AC charging voltage (VCH) from the offboard charging station28to recharge the battery pack20, and (2) a discharging mode, represented by arrow V2X, during which the OBC25offloads power from the battery pack20to an external AC electrical load (L)140. In this manner, the OBC25is bidirectional in its function and, as noted above, capable of providing a split-phase output and a single-phase output. Still referring toFIG.1, the electrified powertrain system10may also include an electronic control unit (ECU)50. The ECU50is operable for regulating ongoing operation of the electrified powertrain system10via transmission of electronic control signals (arrow CCO) to the OBC25and possibly other components or elements of the electrified powertrain system10as needed. The ECU50does so in response to electronic input signals (arrow CCI). For the purposes of the present disclosure, the electronic input signals (arrow CCI) may include communications and/or voltage signals from the offboard charging station28during the above-noted charging mode, requested offloading of power to the external AC electrical load140during V2X operations, etc. During the discharging mode, the electronic input signals (arrow CCI) are indicative of the particular type of AC device or devices forming part of the external AC electrical load140. Such input signals (arrow CCI) may be actively communicated or passively detected in different embodiments, such that the ECU50is operable for determining a particular mode of operation. In response, the ECU50controls operation of the electrified powertrain system10, in particular an internal state of the OBC25as set forth below with reference toFIG.2. To that end, the ECU50shown inFIG.1is equipped with one or more processors (P)52, e.g., logic circuits, combinational logic circuit(s), Application Specific Integrated Circuit(s) (ASIC), electronic circuit(s), central processing unit(s), semiconductor IC devices, etc., as well as input/output (I/O) circuit(s)54, appropriate signal conditioning and buffer circuitry, and other components such as a high-speed clock to provide the described functionality. The ECU50also includes an associated computer-readable storage medium, i.e., memory (M)56inclusive of read only, programmable read only, random access, a hard drive, etc., whether resident, remote or a combination of both. Control routines are executed by the processor52to monitor relevant inputs from sensing devices and other networked control modules (not shown), and to execute control and diagnostic routines to govern operation of the OBC25and possibly other components of the electrified powertrain system10. Referring toFIG.2, the OBC25as contemplated herein includes the I/O coupling points29and a switchgear block30connected thereto. Additionally, the OBC25includes respective first and second DC-AC converters34and134as well as a DC-DC converter36. The first DC-AC converter34and the second DC-AC converter134may each have a respective power capability that is about half of a power capability of the DC-DC converter36as described below. As part of the present approach, the DC-DC converter36operates in two different modes: (1) a voltage mode during which the OBC25ultimately provides the charging voltage to the DC bus22, and (2) a current mode during which the OBC25provides an electrical current to the DC bus22. The OBC25can provide a fixed voltage at its output during mode (1) during limited situations, such as when the battery pack20is not yet connected or the battery voltage needs to be tightly regulated at the end of a charge cycle. Achieving a DC link voltage (VL) in a predetermined range is thus a prerequisite for operating the DC-DC converter36, as appreciated in the art. Presentation of the I/O coupling points29on an outer surface of a waterproof housing125allows the OBC25to be connected to external power for charging operations, and to the external AC electrical load140ofFIG.1during V2X discharging operations. Although omitted fromFIG.2for illustrative clarity and simplicity, those skilled in the art will appreciate that intervening electrical cables and other connection hardware would connect to the I/O coupling points29and extend to the charging port13ofFIG.1for charging, and to a power outlet box46for V2X discharging, with the power outlet box46shown inFIG.4and described below. In this manner, the OBC25is bidirectional in terms of its power flow capability as indicated by respective output and input arrows ACOand ACI. A ground fault circuit interrupter (GFCI)32may be connected between the I/O coupling points29and the switchgear block30in some embodiments for further protection from ground faults during a V2X event. The switchgear block30as illustrated may include three switches31A,31B, and31C. The first DC-AC converter34in this embodiment is connected to a first pair of the three switches, i.e., switches31A and31B, while the second DC-AC converter134is connected to a second pair of the three switches, i.e., switches31B and31C, such that the first DC-AC converter34and the second DC-AC converter134share one of the three switches31A,31B, and31C in common, in this case the switch31B. The three switches31A,31B, and31C may be optionally embodied as mechanical relays or contactors, with solid-state switches being an alternative embodiment. Electrical connections to the charging station28may be established via several voltage pins or terminals (“lines”), including voltage lines L1and a tied neutral (N)/line L2connection, as appreciated in the art. For instance, one may connect an SAE J1772 connector or another suitable connector type to the charging port13ofFIG.1to feed the charging voltage VCHas AC power (arrow ACI) into the OBC25during the charging mode. When discharging the battery pack20ofFIG.1to the external AC electrical load140during V2X operations, additional outlets arranged at a convenient location aboard the motor vehicle11ofFIG.1or the motor vehicle11A ofFIG.4may enable the external AC electrical load140to be connected to a suitable voltage level of the split-phase output. The DC bus22for its part includes respective positive and negative voltage rails, i.e., HVDC+ and HVDC−. For illustrative clarity, the first and second DC-AC converters34and134are labeled with a double-headed arrow and corresponding AC and DC symbols, i.e., ˜ and =, respectively, with the double-headed arrow indicating bidirectional powerflow. Similarly the DC-DC converter36is labeled with the bidirectional powerflow and corresponding DC symbol to indicate the DC conversion process. With respect to the operation of the OBC25, during the charging mode the first DC-AC converter34and the second DC-AC converter134are configured to output the DC link voltage (VL) to the DC-DC converter36. The DC-DC converter36in turn is configured to output a DC charging voltage to the DC bus22when the DC link voltage (VL) reaches a predetermined value, e.g., a variable value based on the factors including the present state of charge of the battery pack20. During the discharging mode, i.e., when powerflow is in the DC-to-AC direction, i.e., right-to-left as one viewFIG.2, the first DC-AC converter34and the second DC-AC converter134are configured to receive a DC discharging voltage or current from the DC-DC converter36and together selectively output a split-phase AC voltage to the switchgear block30. Operation of the switches31A,31B, and31C thereby provides power to the external AC electrical load140ofFIG.1. Referring briefly toFIG.3, a representative split-phase output waveform40is shown in which voltage waveforms42and44of an equal amplitude are 180° out-of-phase relative to one another. Root-mean-square (RMS) values of the illustrated voltage waveforms42and44with peaks of 170 V correspond to an RMS voltage of 120 VRMS, i.e., 170peak2≅120VRMS, with such a value being representative and non-limiting. For simplicity, the RMS subscript is omitted below for 120 V and 240 V example voltages. In such an example, a user may connect a 120 V embodiment of the external AC electrical load140ofFIG.1to an outlet presenting L1(or L2) and N, thus providing a single-phase 120 V output to the external AC electrical load140. Alternatively, a 240 V split-phase load could be connected to a plug presenting lines L1, L2, and N to provide 240 V (between L1and L2) and 120 V (between L1and N or L2and N) power to the external AC electrical load140. Using an SAE J1772 charging plug as an example, such a plug ties together neutral (N) and voltage line L2, with this combination represented inFIG.2as N/L2. Along with voltage line L1, the SAE J1772 connection thus uses two wires for conducting powerflow during charging of the battery pack20via the offboard charging station28ofFIG.1. When discharging to the external split-phase AC electrical load140, however, a third wire is needed, and thus requires the three-wire connector L1, L2, and N as shown inFIG.2. The I/O coupling points29ofFIG.2therefore allow for connection of lines L1, L2, N, and N/L2as shown. Referring to the motor vehicle11A ofFIG.4, existing V2X operations using the OBC25are typically performed by plugging an accessory with an outlet or power strip into the charging port13ofFIG.1to extract AC power from the vehicle. Detection of the power strip in such an implementation is a prerequisite for commencing V2X power offloading through the charging port13. Supplying an AC voltage to terminals of the AC charging port13could pose a shock hazard if the terminals are accessible. The accessory effectively blocks the conductive pins or terminals of the charging port13from the touch hazard. When this accessory is plugged into the charging port13, the vehicle is disabled from driving. In contrast, the present teachings may be implemented by connecting the power outlet box46to the motor vehicle11A at a conveniently accessible location inside and/or outside of the motor vehicle11A. Furthermore, the motor vehicle110A can drive while power is supplied to the power outlet box46. For example, the power outlet box46could be secured within a forward and/or aft storage compartment17and/or19, respectively, or within a passenger compartment of the motor vehicle11A in different embodiments. When the motor vehicle11A is configured as an electric pickup truck as shown, the forward storage compartment17may be used as a front trunk (“frunk”) for transporting cargo, with the power outlet box46possibly mounted therewithin, perhaps flush with a wall to minimize protrusion into volume of the forward storage compartment17. Similarly, the power outlet box46could be mounted within the aft storage compartment19, in this example an open or enclosed truck bed, but possibly a trunk in other embodiments. Other possible locations could be used in other configurations of the motor vehicle11A, or when the host system is an entirely different type of vehicle such as a boat, aircraft, train, etc., and therefore the representative locations ofFIG.4are intended to be illustrative of just two possibilities. In an exemplary implementation, the power outlet box46having power outlets48A and48B at respective first and second voltage levels V1and V2and corresponding receptacle configurations could be presented to a user as V2X power options when powering the external AC electrical load140shown inFIG.1. Optionally, a user could depress a switch (not shown) located outside of the OBC25to selectively energize the power outlets48A and48B when desired. As an illustrative use example, an oven may have a nominal 240 V heating element, an auxiliary power board, and indicator lights, with the latter two features being powered by nominal 120 V power as appreciated in the art. Such an appliance could be connected to the OBC25ofFIG.1by plugging into the aforementioned power outlet48A and powered via the split-phase output described herein. Alternatively, one or more of the power outlets48B could provide single phase power outlet from one of the DC-AC converters34or134, e.g., when powering a radio or lights. The number and placement of the power outlets48A and48B could vary with the particular application. Although the foregoing disclosure has been specified in terms of the representative electrified powertrain system10ofFIG.1and the possible host systems of the motor vehicles11and11A ofFIGS.1and4, respectively, those skilled in the art will appreciate that the described architecture lends itself to performance of a related method for controlling the split-phase bidirectional OBC25having the noted charging and discharging modes. Such a method may proceed as follows. During the charging mode, the method may include controlling, via the ECU50ofFIG.1, the first DC-AC converter and the second DC-AC converter to output the DC link voltage (VL) to the DC-DC converter36. The method may additionally include controlling the DC-DC converter36via the ECU50to output a DC charging voltage or current to the DC bus22when the DC link voltage (VL) reaches a predetermined value. During the discharging mode, the method may include providing a DC discharging voltage or current from the DC-DC converter36to the first DC-AC converter34and the second DC-AC converter134, as well as controlling the first and second DC-AC converters34and134via the ECU50to selectively output a split-phase AC voltage to a switchgear block30ofFIG.2, and to thereby power the external AC electrical load140. Such a method may include receiving AC power via the input connector290B of the switchgear box30during the charging mode, with the input connector290B having the aforementioned L1voltage terminal and the combined L2/N voltage terminal. Also as described above, during the discharging mode the method may include selectively outputting a single-phase AC voltage via the switchgear block30to thereby power the external AC electrical load140with a single-phase AC waveform. In this manner, the split-phase bidirectional OBC25ofFIG.2may be used to provide a wider range of power outputs, with a corresponding reduction in packaging size and mass. These and other attendant benefits will be appreciated by those skilled in the art in view of the forgoing disclosure. The detailed description and the drawings or figures are supportive and descriptive of the present teachings, but the scope of the present teachings is defined solely by the claims. While some of the best modes and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments exist for practicing the present teachings defined in the appended claims. Moreover, this disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below. | 22,859 |
11863005 | DETAILED DESCRIPTION A battery energy storage system (BESS) may include a hierarchical collection of battery cells and may be used to store energy, for example, generated by an associated power plant. For example, a BESS may be used to store energy generated by a photovoltaic power plant (e.g., a so-called “solar farm”), so that such energy may be delivered to a power grid or other load on an as-needed or otherwise as-desired basis. A BESS may include any quantity of battery systems, where a battery system may refer to a collection of battery strings. A battery system may alternatively be referred to as a battery block or battery box, among other possibilities. A battery string may in turn refer to a collection of interconnected battery modules. The battery modules within a battery string may be interconnected in series, but a battery string as described herein may broadly refer to any collection of interconnected battery modules (e.g., battery modules of a battery string may additionally or alternatively be interconnected in parallel). A battery string may alternatively be referred to as a battery rack, among other possibilities. In some cases, battery strings within a battery system may be interconnected with one another in parallel (e.g., each battery string may have a respective input or output node, and for the battery strings of a battery system, such nodes may be coupled with one another). A battery module may in turn refer to a collection of one or more interconnected battery cells, where each battery cell may be configured to store a respective portion of the energy stored by the BESS. A battery cell may alternatively be referred to as a battery, among other possibilities. Battery cells within a battery module may be interconnected in series, in parallel, or in any combination thereof. In some systems, battery management functions may be implemented at different hierarchical levels according to the overall BESS architecture. A component or collection of components configured to implement battery management functions may be referred to as a battery management system (BMS), and a BMS may provide battery management functions for a corresponding storage entity (e.g., a corresponding battery module, a corresponding battery string, or a corresponding battery system). For example, within a BESS, some BMSs may operate at the module level (e.g., Level 1) and be referred to as module BMSs, some BMSs may operate at the string level (e.g., Level 2) and be referred to as string BMSs, and some BMSs may operate at the system level (e.g., Level 3) and be referred to as system BMSs. As described elsewhere herein, in general, a BMS may monitor and control aspects of the corresponding storage entity to support desired operation of the corresponding storage entity. As one such example, a module BMS may ensure that battery cells within the battery module are balanced (e.g., equal or nearly equal) in terms of voltage, current, and capacity levels, such as by charging undercharged battery cells while bypassing overcharged battery cells or by withdrawing from overcharged battery cells while bypassing undercharged battery cells). A BMS thus may measure, monitor, or control various operational aspects (e.g., voltages, currents, states of charge, states of health, temperatures, or the like) for the corresponding storage entity. A BMS at one level of the hierarchy may communicate with and in some cases at least partially manage or be managed by a BMS at another level of the hierarchy. For example, each module BMS may communicate with a string BMS for the battery string that includes the corresponding battery module. In some systems, each string BMS may in turn communicate with a system BMS for the battery system that includes the battery string. Further, in some systems, each system BMS may in turn communicate with an energy management system (EMS), which may coordinate the acceptance of power by the BESS from a power plant (e.g., a photovoltaic power plant) or the delivery of power from the BESS to a power grid (e.g., a utility grid) or other load. A BESS may also include any quantity of circuit protection devices (e.g., fuses, circuit breakers, current transducers, or the like) to provide circuit protection for the components of the BESS. In some systems, circuit protection and one or more other aspects related to electrical operation of the BESS, such as power conversion between different aspects of the BESS that may operate at different voltage levels, may be divorced (e.g., operate independently of, without intercommunication or information exchange) from battery manage aspects of the BESS. For example, a BMS may not monitor or have any awareness of one or more other aspects of BESS operation, such as circuit protection or power conversion functionalities. As described herein, however, one or more power electronics-based (PE-based) BMSs may be introduced into a BESS, which may provide improved efficiency, eliminate or otherwise reduce a quantity of redundant components, or reduced complexity, among other benefits as may be appreciated by one of ordinary skill in the art. For example, a PE-based BMS may be introduced for each battery string (or for pairs of battery strings, as another example) and may provide string-level (e.g., Level-2) BMS functions for the at least one corresponding battery string. A power converter may also be introduced for each battery string (or for pairs of battery strings, as another example) and may convert between a string voltage (e.g., a voltage at which a battery string operates) and some other voltage at which another aspect of the BESS is configured to operate. Such a power converter may be, for example, a direct current (DC) to DC converter or a DC to alternating current (AC) converter. Along with providing one or more battery management functions (e.g., for a battery string), a PE-based BMS as may control or monitor one or more aspects of power converter operation (e.g., for a power converter for the battery string). Further, as a power converter may include various circuit protection components or capabilities, introduction of power converters at the string level within a BESS may allow the elimination of one or more other circuit protection components. Additionally or alternatively, a PE-based BMS as described herein may provide one or more BMS functions conventionally performed by a system BMS and may support the elimination of system BMSs. A PE-based BMS may include, for example, one or more controllers that implement BMS functionalities as described herein and also control a corresponding power converter, or one or more controllers that implement BMS functionalities and communicate or otherwise coordinate with one or more other controllers that control a corresponding power converter and thereby monitor the corresponding power converter. As used herein, a controller may refer to a processor, a microprocessor, a microcontroller, a central processing unit (CPU), application-specific integrated circuit (ASIC), digital signal processor (DSP), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, any collection or combination thereof, or any other circuitry designed to perform the functions ascribed herein to a controller. Additionally or alternatively, a PE-based BMS may include any firmware, software, or algorithm that may be executable (e.g., by one or more controllers) to perform the functions ascribed herein to a PE-based BMS. Aspects of the disclosure are initially described in the context of battery energy storage systems. Aspects of the disclosure are then further described with respect to apparatus diagrams, system diagrams, and flowcharts that relate to PE-based BMSs. FIG.1illustrates an example of a BESS100in accordance with aspects of the present disclosure. The BESS100may include any quantity of battery cells130, battery modules120, and battery strings115, which may be collected into one or more battery systems, along with corresponding module BMSs125, string BMSs105, and system BMSs135. A BESS100may further include an EMS140. Each battery cell130may be configured to store energy and may be configured to operate at a corresponding voltage, which may be referred to as a cell voltage. Each battery module120may include one or more battery cells130. The battery cells130within a battery module120may be interconnected in series, parallel, or any combination thereof. Collectively, the battery cells130within a battery module120may operate at a voltage that may be referred to as a module voltage, which be the same as or different than the cell voltage. For example, if some quantity of the battery cells130within the battery module120are interconnected in series, the module voltage may be greater than the cell voltage. A battery module120may include or otherwise be coupled with a corresponding module BMS125, which may provide various battery management functions for the battery module120(e.g., to control and monitor the battery cells130of the battery module120). For example, a battery module120may include or be coupled with one or more sensors, and a module BMS125may receive and monitor information provided by such sensors (e.g., voltage, current, state of charge, capacity, headroom, state of health, or temperature information for the battery cells130of the battery module120). As another example, a module BMS125may manage the battery module120to balance (e.g., align, maintain as equal or nearly equal) the battery cells130within the battery module120with respect to voltage, current, capacity, charge (e.g., state of charge), headroom levels, among other possible metrics. As another example, a module BMS125may provide circuit protection or other forms of protection for the battery cells130within the battery module120. For instance, a battery module120may include one or more switches (e.g., transistors), and a module BMS125may control the operation of such switches to charge one or more undercharged battery cells130while bypassing one or more overcharged battery cells130or discharge one or more overcharged battery cells130while bypassing one or more undercharged battery cells130, or to disable or isolate one or more defective or at-risk (e.g., overheated) battery cells130, among other possibilities. Battery management functions provided by a module BMS125may in some cases be referred to as Level 1 battery management functions. A module BMS125may include a controller to implement or manage the functionalities ascribed herein to a module BMS125. Each battery string115may include some quantity of battery modules120. The battery modules120within a battery string115may be interconnected in series, parallel, or any combination thereof. Collectively, the battery modules120within a battery string115may operate at a voltage that may be referred to as a string voltage, which be the same as or different than the module voltage. For example, in cases where some quantity of the battery modules120within the battery string115are interconnected in series, the string voltage may be greater than the module voltage. A battery string115may include or otherwise be coupled with a corresponding string BMS105, which may provide various battery management functions for the battery string115(e.g., to control and monitor the battery modules120of the battery string115). For example, a string BMS105may provide like functionalities as described herein for a module BMS125, but with respect to the battery modules120of a battery string115rather than the battery cells130of a battery module120. Further, a string BMS105for a battery string115may communicate with (e.g., exchange information with) each module BMS125for the battery string115. For example, a string BMS105may receive information from a module BMS125such as status information for the corresponding battery module120(e.g., data regarding a voltage, current, charge, capacity, temperature or the like for the battery module120). Battery management functions provided by a string BMS105may in some cases be referred to as Level 2 battery management functions. A module BMS125may include a controller to implement or manage the functionalities ascribed herein to a module BMS125. In some cases, a BESS100may further include a respective switchgear110for each battery string115. A switchgear110may provide an electrical interface for the corresponding battery string115(e.g., to support coupling of the battery string115with one or more other components) along with one or more circuit protection functions for the corresponding battery string115. For example, a switchgear110may include any quantity of fuses, circuit breakers, current transducers, current sensors or other circuit protection circuitry. In some cases, a switchgear110may monitor a string voltage for a battery string115, or the current to or from the battery string115, or both and may isolate the battery string115(e.g., disconnect the battery string115from other aspects of the BESS100) if the voltage or current is excessive or for some other reason (e.g., maintenance). In some cases, a switchgear110for a battery string115may include the string BMS105for the battery string115. A collection of battery strings115may in some cases be referred to as a battery system, or alternatively as a battery block or battery box, among other possibilities. For example, battery strings115-a,115-b, and115-c—possibly along with any quantity of additional battery strings115—may be included in a same battery box. In some cases, a battery system may correspond to (e.g., include or be included in) an enclosure that includes the battery strings115of the battery system. The enclosure may be, for example, a building, a container, or any other type of enclosure. A battery system may include or otherwise be coupled with a corresponding system BMS135, which may provide various battery management functions for the battery system (e.g., to control and monitor the battery strings115of the battery system). For example, a string BMS105may provide like functionalities as described herein for a module BMS125, but with respect to the battery strings115of a battery system rather than the battery cells130of a battery module120. For example, a system BMS135may manage the battery system to balance (e.g., align, maintain as equal or nearly equal) the battery strings115within the battery module120with respect to voltage, current, capacity, charge (e.g., state of charge), headroom levels, among other possible metrics. As another example, a system BMS135may control the operation of the switchgears110or other switching components within the battery system to isolate any defective or deactivated battery string115. Further, a system BMS135for a battery system may communicate with (e.g., exchange information with) each string BMS105for the battery system. For example, a system BMS135may receive information from a string BMS105such as status information for the corresponding battery string115(e.g., data regarding a voltage, current, charge, capacity, temperature or the like for the battery string115). A system BMS135may also receive information from module BMSs125within the battery system (e.g., as relayed to the system BMS135by the string BMSs105), such as status information for the corresponding battery modules120. Battery management functions provided by a system BMS135may in some cases be referred to as Level 3 battery management functions. A system BMS135may include a controller to implement or manage the functionalities ascribed herein to a system BMS135. A BESS100may include any quantity of battery systems, and thus any quantity of system BMSs135. Each system BMS135within the BESS may communicate with the EMS140. The EMS may coordinate the acceptance of power by the BESS from a power plant (e.g., a photovoltaic power plant) or the delivery of power from the BESS to a power grid (e.g., a utility grid) or other load. In some cases, a BESS100may include a central power converter (not shown), such as a DC-to-DC or DC-to-AC converter for example, to convert between a voltage output by one or more battery systems (e.g., the string voltage of the battery strings115within the battery system) and a voltage of the power grid or other load, or to convert between a voltage output by the power plant and a voltage input to the one or more battery systems (e.g., the string voltage of the battery strings115within the battery system). FIG.2illustrates an example of a BESS200in accordance with aspects of the present disclosure. The BESS200may include any quantity of battery cells230and battery modules220, along with corresponding module BMSs225, which may be examples of battery cells130, battery modules120, and module BMSs125as described herein. Battery modules220may be grouped into battery strings215. Each battery string215may include some quantity of battery modules220, which may be interconnected in series, parallel, or any combination thereof. Collectively, the battery modules220within a battery string215may operate at a voltage that may be referred to as a module voltage, which be the same as or different than the cell voltage of the battery cells230. For example, in cases where some quantity of the battery modules220within the battery string215are interconnected in series, the string voltage may be greater than the module voltage. Each battery string215may include or otherwise be coupled with both a respective power converter210and a corresponding PE-based BMS205. The power converter210may include various power electronics circuitry (e.g., one or more power switches such as power metal-oxide-semiconductor field-effect transistors (MOSFETs) or other types of switches such as other types of transistors, one or more capacitors, one or more inductors) and may be configured to convert between the string voltage of the corresponding battery string215and some other voltage. The other voltage may have a magnitude that is the same as, lower than, or higher than the string voltage. The string voltage may be a DC voltage, and the other voltage may be either a DC or an AC voltage—that is, the power converter210may be a DC-to-DC converter or a DC-to-AC converter (e.g., an inverter). In some cases, the power converter210may be a switch-mode power converter and may operate one or more switching components according to one or more duty cycles, in accordance with a pulse-width modulation algorithm, or any combination thereof in order to covert between the string voltage and the other voltage. The power converter210may also be a bidirectional power converter, and currently be able to flow into or out of the battery string215through the power converter210. The power converter210may also include one or more electronic (e.g., overcurrent or overvoltage) protection components, such as circuit breakers, current transducers, isolation switches, fuses, or the like. Additionally or alternatively, in some cases, one or more aspects of the power electronics circuitry within the power converter210may be operable to provide a power conversion function along with an circuit protection function. For example, one or more switches (e.g., power switches) within the power converter210may be operable to isolate the corresponding battery string215from other aspects of the BESS200. Accordingly, the BESS200may not include any switchgears110as described with reference toFIG.1, which may reduce a presence of redundant components, reduce complexity of the BESS200, or improve the efficiency of the BESS200, among other possible benefits that may be appreciated by one of ordinary skill in the art. The PE-Based BMS205for a battery string215may implement one or more battery management functions for the battery string215(e.g., to control and monitor the battery modules220of the battery string215). For example, the PE-Based BMS205may implement any one or more Level 2 (e.g., string level) battery management functions described elsewhere herein (e.g., any functions ascribed herein to a string BMS105as descried with reference toFIG.1). Additionally, in some cases the PE-Based BMS205may implement any one or more Level 3 (e.g., system level) battery management functions described elsewhere herein (e.g., any functions ascribed herein to a system BMS135as descried with reference toFIG.1). Accordingly, the BESS200may not include any system BMSs135as described with reference toFIG.1. Thus, BESS200may have a two-tier hierarchy with respect to battery management, as opposed to, for example, a three-tier hierarch as described with reference toFIG.1, which may reduce a presence of redundant components, reduce complexity of the BESS200, or improve the efficiency of the BESS200, among other possible benefits that may be appreciated by one of ordinary skill in the art. For example, a PE-based BMS205may communicate with each module BMS225within the corresponding battery string215as well as an energy management system240(which may be an example of an energy management system140as described with reference toFIG.1). For example, a battery string215or the battery modules220therein may include or be coupled with one or more sensors, and a PE-Based BMS205may receive and monitor information provided by such sensors (e.g., voltage, current, state of charge, capacity, headroom, state of health, or temperature information for the battery modules220or the battery cells230therein). Additionally or alternatively, a PE-Based BMS205may receive and monitor information provided by such sensors for the battery string215as a whole (e.g., voltage, current, state of charge, capacity, headroom, state of health, or temperature information for the battery string215). In some cases, a PE-Based BMS205may transmit one or more aspects of string-level, module-level, or cell-level information (e.g., status information) as described herein to the EMS240. A PE-Based BMS205may receive information (e.g., control signals) from the EMS240(e.g., requests for status information or other aspects of string-level, module-level, or cell-level information as described herein) and transmit information or commands to the module BMSs225of the corresponding battery string215. A PE-based BMS205may manage the battery string215to balance (e.g., align, maintain as equal or nearly equal) the battery modules220within the battery string215with respect to voltage, current, capacity, charge (e.g., state of charge), headroom levels, among other possible metrics. Additionally or alternatively, a PE-based BMS205may provide circuit protection or other forms of protection for the battery modules220within the battery string215. For instance, a battery string215or battery modules220therein may include one or more switches (e.g., transistors), and a PE-based BMS205may control the operation of such switches to charge one or more undercharged battery modules220while bypassing one or more overcharged battery modules220or discharge one or more overcharged battery modules220while bypassing one or more undercharged battery modules220, or to disable or isolate one or more defective or at-risk (e.g., overheated) battery modules220, among other possibilities. Additionally or alternatively, a PE-based BMS205may provide circuit protection or other forms of protection for the battery string215as a whole. For example, a PE-based BMS205may control the operation of the power converter210or one or more other switching components within the corresponding battery string215or the battery system to isolate the battery string215(e.g., if the battery string215becomes defective or at-risk of becoming overcharged or otherwise damaged such as by an excessive input or output current or excessive string voltage, or based on signaling from the EMS240). Along with providing one or more battery management functions for a corresponding battery string215, a PE-based BMS205may monitor, control, or both one or more aspects of the operation of the power converter210for the corresponding battery string215. For example, a PE-based BMS205may monitor or control the operation of one or more aspects of the power electronics circuitry within the corresponding power converter210. As one such example, a PE-based BMS205may monitor or control the operation of one or more switches (e.g., power switches) within the corresponding power converter210, such as the duty cycle of one more switches, to achieve conversion between the string voltage (which may be an input or output voltage of the power converter210) and some other voltage (which may correspondingly be another output or input voltage of the power converter210). For example, the PE-based BMS205may monitor or control the operation of one or more switches in accordance with a pulse-width modulation algorithm to achieve conversion between the string voltage and the other voltage. In some cases, the PE-based BMS205may monitor and receive information from one or more sensors associated with the power converter210or the corresponding battery string215, such as information regarding the string voltage or string current (e.g., current into or out of the string) or a target string voltage or string current, or information regarding the other input or output voltage or current of the power converter210or a target value thereof. The PE-based BMS205may control the operation of one or more aspects of the power converter210(e.g., one or more switches thereof) based on such information. In some cases, the PE-based BMS205may comprise a single controller (e.g., fabricated on a single semiconductor die). In other cases, the PE-based BMS205may comprise two or more controllers (e.g., fabricated on two or more semiconductor dies) that are communicatively coupled with one another. For example, one or more controllers may control operation of the power converter210, and one or more other controllers may provide battery management functionalities as ascribed herein to a PE-based BMS, and such controllers may exchange information to coordinate such functionalities (e.g., manage the operation of the battery modules220of the battery string215based on operational information for the power converter210, or manage operation of the power converter210based on operational information for the battery string215or battery modules220therein). FIG.3illustrates an example of aspects of a BESS300in accordance with aspects of the present disclosure. In some cases, the BESS300may include or be included in aspects of the BESS200described with reference toFIG.2. For example,FIG.2may illustrate communicative connections between one or more components of a BESS in accordance with aspects of the present disclosure, whileFIG.3may illustrate electrical connections between one or more components of the BESS. BESS300may include a set of battery strings305and respective sets of battery modules315, which may be examples of battery strings215and battery modules220as described with reference toFIG.2. Each battery string305may also include a PE-based BMS310, which may be an example of PE-based BMS205as described with respect toFIG.2. The set of battery strings305and corresponding PE-based BMSs310may be connected to additional connections345. Example options for additional connections345may be further described elsewhere herein, including with respect toFIG.4. PE-based BMSs310and battery strings305may be connected to the additional connections345via a battery combiner box340. Battery combiner box340may include switch355, which may be operable to selectively connect the battery combiner box340to or disconnect the battery combiner box from the additional connections345. Additionally or alternatively, the battery combiner box340may include one or more other circuit protection components335(e.g., circuit breakers, fuses, current transducers, or the like). For example, battery string305-aand PE-based BMS310-amay be connected to circuit protection component335-a. The battery combiner box340may include a common node to which each of the battery strings305may be coupled (e.g., through the circuit protection components335), such as the node of the BESS300between the circuit protection components335and the switch355. Current may flow into or out of the battery strings305through the battery combiner box340. In some cases, the battery strings305and battery combiner box340of the BESS300may all be included in a battery system as described herein. In other cases, the battery combiner box340may be outside of a battery system as described herein, and the battery strings305may be distributed across any quantity (e.g., one or more) of battery systems as described herein. The PE-based BMSs310may each include a respective set of components to perform the functions ascribed herein to a PE-based BMS. For example, each PE-based BMS310may include one or more switches350(e.g., isolation switches), contactors320, power converters330, and current transducers325, along with one or more controllers that may control the operation of such components. A power converter330may be an example of a power converter210as described with reference toFIG.2. Current transducers325may in some cases comprise shunt resistors, such as high-accuracy shunt resistors. A PE-based BMS310thus may integrate one or more circuit protection components (e.g., switches350-aand350-b, current transducers325, or other overcurrent or overvoltage protection devices, which may eliminate the inclusion of a switchgear for each battery string305. Additionally or alternatively, as described herein, a power converter330may include or otherwise provide various circuit protection functionalities, such as one or more circuit breakers, one or more current transducers, or one or more switches that may be operable to selectively isolate the corresponding battery string305(or at least other aspects thereof) from other aspects of the BESS300(e.g., from the battery combiner box340). Thus, a PE-based BMS310may reduce or eliminate the presence of otherwise duplicative circuit protection components, such as switchgears. Further, the inclusion of multiple string-level power converters330(e.g., a power converter330for each battery string) may eliminate the need for one or more other more centralized power converters to which multiple of the battery strings305may otherwise be coupled in other systems (e.g., a more centralized power converter that may otherwise be included in the additional connections345). FIGS.4A and4Billustrate examples of systems401and402that support PE-based BMS in accordance with aspects of the present disclosure. In some examples, systems401and402may be coupled with aspects of a BESS as described herein, such as BESS200or BESS300. Each system401and402may include aspects of the additional connections345described with respect toFIG.3. For example, the battery storage connections415-aof system401or the battery storage connections415-bof system402may each include any quantity of battery combiner boxes340as shown inFIG.3(e.g., the additional connections345of BESS300may include either the battery storage connections415-aof system401or the battery storage connections415-bof system402). Referring toFIG.4A, system401may include a transformer405-aand circuit breaker410-a. Battery storage connections415-amay output or take as an input a first AC voltage. For example, battery storage connections415-amay represent or be coupled with any quantity of battery combiner boxes340as described herein, which may in turn be coupled with power converters330that are DC-to-AC converters and convert between corresponding DC string voltages and the first AC voltage. Transformer405-amay convert between the first AC voltage and a second AC voltage for connection to another component. For example, transformer405-amay transform the first AC voltage to a higher or otherwise different AC voltage in order to connect a BESS (by way of battery storage connections415-a) to an electrical power grid or other AC load or source. Referring toFIG.4B, system402may be an example of a system that connects battery storage to a grid, and also connects energy production to battery storage. Battery storage connections415-bmay represent or be coupled with any quantity of battery combiner boxes340as described herein, which may in turn be coupled with power converters330that are DC-to-DC converters and convert between corresponding DC string voltages and some other DC voltage. Power plant connections420may represent the output of a power plant, such as a photovoltaic power plant (e.g., solar farm). Battery storage connections415-bmay be connected to a first circuit protection box425, which may include one or more circuit protection components (e.g., circuit breakers, fuses, current transducers, or the like). Power plant connections420may connect to a second circuit protection box430, which may include one or more circuit protection components (e.g., circuit breakers, fuses, current transducers, or the like). Second circuit protection box430may further include or alternatively be coupled with a switch435, which may be operable to selectively couple or decouple power plant connections420(and thus the associated power plant) from node440(and thus from battery storage connections415-band the associated BESS, and also thus from power conversion box445). Power conversion box445may include one or more circuit protection components, such as current transducer442and circuit breaker410-b, along with a power converter450. The power converter450may be a DC-to-AC converter and may convert (e.g., bidirectionally) between a DC voltage at node440(which may be supplied by the power plant connections420or the battery storage connections415-b, or which may be supplied to the battery storage connections415-b) and a first AC voltage input to or output by the transformer405-b. Transformer405-amay convert between the first AC voltage and a second AC voltage, which may be supplied to or provided by an electrical power grid or other AC load or source. WhileFIGS.4A and4Billustrate example topologies for connecting a BESS as described herein with a one or more other power sources or loads, one of ordinary skill in the art will appreciate that other topologies may be used in conjunction with a BESS as described herein and further that aspects of the example topologies ofFIGS.4A and4Bmay be combined. FIG.5illustrates an example of aspects of a BESS500in accordance with aspects of the present disclosure. In some examples, BESS500may include or be included in aspects of BESS200or BESS300as described herein. BESS500may include battery modules515, which may be examples of battery modules220and315as described herein. Battery modules515may include or otherwise be coupled with respective module BMSs520, which may be example of module BMSs225as described herein. The modules515illustrated inFIG.5may be interconnected as part of a battery string525, which may be an example of a battery string115or215as described herein. The battery string525may be coupled with circuitry550. Circuitry550may include, for example, a switch530-a(e.g., an isolation switch) in series with a contactor535, a current transducer540, a power converter545, and an additional switch530-b(e.g., an isolation switch). The power converter545may be an example of a power converter210as described herein and may, for example, be a DC-to-DC or DC-to-AC converter and a unidirectional or bidirectional power converter. In some cases, the power converter545may be a switch mode power converter and may include one or more switches555. Circuitry550may further include one or more sensors510. Sensors510may monitor one or more operational characteristics of the power converter545or other aspects of circuitry550and output indications thereof. For example, sensors510may include one or more voltage sensors and may monitor an input voltage of the power converter545, an output voltage of the power converter545, or both, either of which may correspond to a string voltage of the battery string525in some cases. As another example, sensors510may include one or more current sensors and may monitor an input or output current of the power converter545, or both, either of which may correspond to an input or output current of the battery string525in some cases. In some cases, current transducer540may be included in or coupled with sensors510, and current transducer540may generate a signal indicative of the input or output current of the power converter545. The BESS500may include one or more controllers505, which may implement the functions ascribed herein to a PE-based BMS as described herein. For example, the module BMSs520of the battery string525may be communicatively coupled with controller505-a. Controller505-amay implement one or more battery management functions ascribed herein to a PE-based BMS based on information exchanged with the module BMSs520. For example, controller505-amay receive and monitor information regarding the battery modules515(e.g., voltage, current, state of charge, capacity, headroom, state of health, or temperature information for the battery modules515or the battery cells therein) from the module BMSs520. Additionally or alternatively, controller505-amay receive and monitor information for the battery string525as a whole (e.g., voltage, current, state of charge, capacity, headroom, state of health, or temperature information for the battery string525). Controller505-amay transmit one or more aspects of string-level, module-level, or cell-level information (e.g. status information) as described herein to the EMS560, which may be an example of an EMS240as described herein. Controller505-amay receive information from the EMS560and transmit information or commands to the module BMSs520of the corresponding battery string525. In some cases, controller505-amay control one or more operational aspects of the circuitry550as described herein with reference to a PE-based BMS (e.g., with reference to a PE-based BMS205), including the power converter545, one or more circuit protection components (e.g., switches530), and sensors510. For example, controller505-amay receive voltage information, current information, or other information from sensors510and control one or more operational aspects of the circuitry550and the power converter545based upon such information. In some cases, functions ascribed herein to a PE-based BMS may be performed by two or more controllers that may be communicatively coupled and exchange information and commands with one another. For example, BESS500may include controller505-b, which may be communicatively coupled and exchange information and commands with controller505-a. For example, controller505-bmay receive voltage information, current information, or other information from sensors510and control one or more operational aspects of the circuitry550and the power converter545based upon such information, and controller505-bmay provide related status or other information to controller505-a, which may manage battery string525based upon such information as received from controller505-b. In some cases, controller505-amay transmit one or more aspects of status information regarding the power converter545or other aspects of the circuitry550to the EMS560. The inclusion in BESS500of a PE-based BMS that includes one or more controllers505and power converter545may replace the use of separate string level and system level BMSs, circuit protection components such as switchgears, a more centralized power converter responsible for converting the string voltages of multiple battery strings, or any combination thereof that may be present in other systems. This may provide reliability, simplicity, efficiency, and other benefits as may be appreciated by one of ordinary skill in the art. FIG.6illustrates an examples of aspects of system600in accordance with aspects of the present disclosure. In some examples, system600may include or be included in aspects of BESS200, BESS300, or BESS500. System600may represent an example of a topology in which one PE-based BMS605corresponds to one or more battery strings610. In some cases, the one PE-based BMS605may corresponds to one battery string610-a. In other cases, the one PE-based BMS605may correspond to two battery strings610-aand610-b. Each battery string610may be an example of a battery string215as described herein and may include any quantity of battery modules615and corresponding module BMSs620, which may be examples of battery modules220module BMSs225as described herein. PE-based BMS605may be an example of a PE-based BMS as described elsewhere herein and may perform battery management functions for the battery string610-aor for battery strings610-aand610-b. PE-based BMS605-amay also monitor or control power converter635, which may be an example of a power converter210as described herein. PE-based BMS605may also monitor or control one or more other circuit protection components and sensors, such as switches645, contactor625, potential transducers (PTs)650, and current transducers (CTs)630. In some cases, PE-based BMS605, power converter635, and such circuit protection components and sensors may be included in a PE-Based BMS unit660. PTs650may be examples of voltage sensors. PT650-amay measure a first voltage, which may be an input or output voltage for power converter635(e.g., a voltage before or after voltage conversion by power converter635). The first voltage may be a DC voltage at which the one or more battery strings610receive or output power. PT650-amay indicate the measured first voltage to PE-based BMS605. PT650-bmay measure a second voltage, which may be a corresponding output or input voltage for power converter635(e.g., a voltage after or before conversion by power converter635). The second voltage may be a DC or AC voltage at which the power converter635receives or outputs power. PT650-bmay indicate the measured second voltage to PE-based BMS605. CTs630may be examples of current sensors. CT630-amay measure a first current, which may be an input or output current for power converter635(e.g., a current before or after voltage conversion by power converter635). The first current may correspondingly be an output or input current for the one or more battery strings610and may be a DC current. CT630-amay indicate the measured first voltage to PE-based BMS605. CT630-bmay measure a second current, which may be a corresponding output or input current for power converter635(e.g., a current after or before conversion by power converter635) and may be a DC or AC current. CT630-bmay indicate the measured second current to PE-based BMS605. PE-Based BMS605may monitor operational aspects of the one or more battery strings610and power converter635based on the voltage and current information received by PE-Based BMS605from the PTs650and CTs630, including making related energy and power determinations. Switches645may be examples of any component operable to selectively couple or electrically isolate two or more nodes, such as, for example, isolation switches, circuit breakers, or additional circuit protection devices (e.g., fuses), either alone or in any combination. Switch645-amay be operable to selectively couple or decouple the one or more battery strings610from other aspects of the system600(e.g., from power converter635) and thereby may provide circuit protection (e.g., protection from excessive voltages or currents) for the one or more battery strings610. Switch645-bmay be operable to selectively couple or decouple power converter635from a source or load for the power converter635(not shown) and thereby may provide circuit protection for power converter635along with any components coupled with the other side of power converter635(e.g., battery strings610). PE-based BMS605may control whether switches645are closed or open (e.g., whether two or more nodes coupled with a switch645are coupled with each other or electrically isolated from each other). For example, PE-based BMS605may control whether switches645are closed or open based on information from one or more PTs650, one or more CTs630, or any combination thereof (e.g., PE-based BMS605may open a switch645if a sensed voltage or current exceeds a corresponding threshold). In some cases, a switch645may transmit feedback signaling to PE-based BMS605, including to indicate a state of the switch645—e.g., whether the switch645is on or off (open or closed) or faulted. Power converter635may an example of a power converter210as described herein and may include one or more switches (e.g., semiconductor switches, such as MOSFETs, bipolar junction transistors (BJTs), or any other type of semiconductor switch). In some examples, PE-Based BMS605may directly control the operation of one or more switches within power converter635. For example, PE-Based BMS605may send control signals to power converter635to activate or deactivate one or more individual switches therein, to implement a related pulse-width modulation algorithm, control a duty cycle for the one or more switches, or otherwise cause the one or more switches to operate so as to achieve a desired performance of the power converter635(e.g., a desired magnitude or phase of an output voltage, a desired magnitude or phase of an output current, a desired magnitude or angle of an output power, or the like). In other examples, PE-Based BMS605may send signals to supplemental controller665indicating one or more such desired performance metrics for the power converter635, and supplemental controller665may directly control the operation of one or more switches within power converter635(e.g., may implement a pulse-width modulation algorithm, may achieve a target duty cycle, or any combination thereof) in order to achieve the performance requested by PE-Based BMS605. Supplemental controller665may be anywhere communicatively between PE-Based BMS605and the one or more switches of power converter635and, though illustrated in the example ofFIG.6as separate from PE-Based BMS605and power converter635, may in other examples be included within (e.g., integrated into) PE-Based BMS605or power converter635. In some cases, PE-Based BMS605may be an example of a controller505-a, and supplemental controller665may be an example of a controller505-bas described with reference toFIG.5. Power converter635(and, if present, supplemental controller665may communicate status information for the power converter635(and, if present, supplemental controller665) back to PE-based BMS605. PE-based BMS605may also control (e.g., send control signals to) and receive status or other feedback information from conditioning circuit655. As part of initiating system600, conditioning circuit655may be configured to precharge one or more other components of the system600(e.g., power converter635, switches645) to be at voltage levels within ranges or otherwise at levels suitable for such components to begin normal operation. Such precharging may, for example, avoid inrush currents or other phenomena that could cause damage to various components of system600by adjusting related voltages to be at suitable levels in a controlled fashion (e.g., relatively gradually). PE-based BMS605may cause (e.g., instruct, command) conditioning circuit655to precharge one or more other components of system600and may receive status information from conditioning circuit655indicating whether such components have been successfully precharged. PE-based BMS605may also control whether contactor625is open or closed, and in some cases PE-based BMS605may send a signal to close contactor625may based on an indication from conditioning circuit655indicating that one or more other components of the system600(e.g., power converter635) have been successfully precharged. PE-based BMS605may in some cases also receive status information from contactor625(e.g., indicating whether contactor625is open or closed). PE-Based BMS605may control any of the one or more battery strings610, power converter635, switches645, and contactor625based on commands from EMS670and may send to EMS670status information for any component from which PE-Based BMS605receives status information. In some cases, for example, EMS670may send a charge command to PE-Based BMS605, which may indicate a power level and duration for charging the one or more battery strings610, and PE-Based BMS605may control the one or more battery strings610, power converter635, switches645, contactor625, or any combination to charge the one or more battery strings610in accordance with the charge command. Similarly, as another example, EMS670may send a discharge command to PE-Based BMS605, which may indicate a power level and duration for discharging the one or more battery strings610, and PE-Based BMS605may control the one or more battery strings610, power converter635, switches645, contactor625, or any combination to discharge the one or more battery strings610(e.g., to output power from the one or more battery strings610) in accordance with the discharge command. Other examples of commands or other information that may be received by a PE-Based BMS605from the EMS670may include reactive power set points for power converter635, on/off commands for the PE-Based BMS605or any component controlled by PE-Based BMS605, an emergency shutoff command for a battery string610controlled by PE-Based BMS605, voltage or frequency ride through set points for a power source or load for power converter635, a ramp rate set point for power converter635, or a battery pre-charge command for a battery string610, or any combination thereof. In some cases, examples of information that a PE-Based BMS605may send to EMS670may include status information for a battery string610, power converter635, or component thereof, such as input or output voltages, currents, or power levels for power converter635; voltage, current, temperature, state of charge, or state of health information for a battery string610, battery module615, or battery cell; status information for one or more circuit protection devices such as switches645or contactor625; or fault information for the PE-based BMS605or any component controlled by PE-based BMS605; or any combination thereof. Additionally or alternatively, in some cases, EMS670and PE-Based BMS605may exchange signaling related to a firmware update or diagnostic procedure for PE-Based BMS605or any component controlled by PE-based BMS605. It is to be understood that any BESS described herein may be adapted to include a topology such as shown inFIG.6. FIG.7shows a block diagram700of a controller720that supports power electronics based battery management system in accordance with aspects of the present disclosure. The controller720, or various components thereof, may be an example of a PE-based BMS or other means for performing various aspects of PE-based battery management as described herein. For example, the controller720may include a power control component725, a circuitry control component730, a battery management component735, a voltage monitor component740, a current monitor component745, a charge monitor component750, a capacity monitor component755, a temperature monitor component760, a balancing component765, a module control component770, a communication component775, or any combination thereof. Each of these components may communicate, directly or indirectly, with one another (e.g., via one or more buses). The power control component725may be configured as or otherwise support a means for controlling a power converter, the power converter configured to convert between a first voltage and a second voltage different than the first voltage. The battery management component735may be configured as or otherwise support a means for exchanging signaling with each battery module of a set of battery modules, wherein the set of battery modules is configured to receive power from or output power to the power converter. The battery management component735may be configured as or otherwise support a means for implementing a set of battery management functions for the set of battery modules based at least in part on exchanging the signaling with each battery module of the set of battery modules. In some examples, the controller may be implemented on a single semiconductor die. In some examples, the controller may be implemented on a plurality of semiconductor dies. In some examples, to control the power converter, the power control component725may be configured as or otherwise support a means for selectively activating and deactivating one or more switches of the power converter, selectively the. In some examples, based at least in part on selectively activating and deactivating at least one switch of the one or more switches of the power converter, the power control component725may be configured as or otherwise support a means for controlling a duty cycle of the at least one switch. In some examples, based at least in part on selectively activating and deactivating at least one switch of the one or more switches of the power converter, the power control component725may be configured as or otherwise support a means for operating the at least one switch according to a pulse-width modulation algorithm. In some examples, the current monitor component745may be configured as or otherwise support a means for receiving signaling indicating a magnitude of an input current for the power converter, signaling indicating a magnitude of an output current for the power converter, or both, and the power control component725may be configured as or otherwise support a means for controlling the power converter based at least in part on the receiving the signaling indicating the magnitude of the input current for the power converter, the signaling indicating the magnitude of the output current for the power converter, or both. In some examples, the voltage monitor component740may be configured as or otherwise support a means for receiving signaling indicating a magnitude of an input voltage for the power converter, signaling indicating a magnitude of an output voltage for the power converter, or both, and the power control component725may be configured as or otherwise support a means for controlling the power converter based at least in part on the receiving the signaling indicating the magnitude of the input voltage for the power converter, the signaling indicating the magnitude of the output voltage for the power converter, or both. In some examples, the circuitry control component730may be configured as or otherwise support a means for selectively activating and deactivating a first switch configured to selectively couple a first node of the power converter with the set of battery modules, and selectively activating and deactivating a second switch configured to selectively couple a second node the power converter with a load or power source. In some examples, the circuitry control component730may be configured as or otherwise support a means for controlling a contactor configured to selectively couple a first node of the power converter with the set of battery modules. In some examples, the circuitry control component730may be configured as or otherwise support a means for controlling a conditioning circuit to precharge an input voltage the power converter, an output voltage of the power converter, or both, coupling a first node of the power converter with the set of battery modules after precharging the input voltage the power converter, the output voltage of the power converter, or both, and coupling a second node of the power converter with a load or power source after precharging the input voltage the power converter, the output voltage of the power converter, or both. In some examples, the power control component725may be configured as or otherwise support a means for monitoring one or more operating characteristics of the power converter, and control the power converter based at least in part on the monitoring. In some examples, to implement the set of battery management functions for the set of battery modules, voltage monitor component740may be configured as or otherwise support a means for monitoring a voltage output by each battery module of the set of battery modules. In some examples, to implement the set of battery management functions for the set of battery modules, current monitor component745may be configured as or otherwise support a means for monitoring a current output by each battery module of the set of battery modules. In some examples, to implement the set of battery management functions for the set of battery modules, charge monitor component750may be configured as or otherwise support a means for monitoring an extent of charge for each battery module of the set of battery modules. In some examples, to implement the set of battery management functions for the set of battery modules, capacity monitor component755may be configured as or otherwise support a means for monitoring a capacity of each battery module of the set of battery modules. In some examples, to implement the set of battery management functions for the set of battery modules, temperature monitor component760may be configured as or otherwise support a means for monitoring a temperature of the set of battery modules. In some examples, to implement the set of battery management functions for the set of battery modules, balancing component765may be configured as or otherwise support a means for balancing respective voltages, respective currents, or any combination thereof across a plurality of battery modules within the set of battery modules. In some examples, to implement the set of battery management functions for the set of battery modules, module control component770may be configured as or otherwise support a means for selectively enabling or disabling a battery module of the set of battery modules. In some examples, communication component775may be configured as or otherwise support a means for communicating status information for the set of battery modules with an energy management system. In some examples, power control component725may be configured as or otherwise support a means for controlling the power converter based at least in part on signaling received from the energy management system. In some examples, battery management component735may be configured as or otherwise support a means for controlling the set of battery modules based at least in part on signaling received from the energy management system. FIG.8shows a flowchart illustrating a method800in accordance with various aspects of the present disclosure. The operations of the method800may be implemented by a PE-based BMS or its components as described herein. For example, the operations of the method800may be performed by a PE-based BMS as described with reference toFIGS.2through6. In some examples, a PE-based BMS may execute a set of instructions (e.g., firmware or software as may be stored on one or more computer-readable media) to perform the described functions. Additionally or alternatively, the PE-based BMS may perform aspects of the described functions using special-purpose hardware. At805, the method may include performing an initialization routine. For example, as part of performing the initialization routine, the PE-based BMS may establish and verify communications with an EMS and any quantity of module BMSs included in a battery string controlled by the PE-based BMS. As another example, as part of performing the initialization routine, the PE-based BMS may send initialization signals to one or more other components coupled with the PE-based BMS (e.g., battery strings or components thereof, a power converter, switches or other circuit protection components), which may cause the one or more other components to each perform a respective initialization routine. Additionally or alternatively, example, as part of performing the initialization routine, the PE-based BMS may check the status (e.g., state of health) of any components coupled with the PE-based BMS to verity that the component is in a suitable condition to begin operating. At810, which in some cases may occur after performing the initialization routine at805, the PE-based BMS may precondition a power converter controlled by the PE-based BMS. For example, the PE-based BMS may configure one or more operating parameters for the power converter (e.g., voltage, current, or power set points). As another example, the PE-based BMS may cause a conditioning circuit such as conditioning circuit655described with reference toFIG.6to precharge the power converter or one or more other components coupled with the power converter. Based on preconditioning the power converter, for example, the PE-based BMS may ensure one or more voltages associated with the power converter (e.g., voltages at input or output nodes of the power converter) are within ranges such that the power converter can safely being operating. At815, which in some cases may occur after performing the initialization routine at805, the PE-based BMS may precondition a battery string (e.g., one battery string or two battery strings) controlled by the PE-based BMS. In some cases, preconditioning a battery string at815may occur at least partially concurrently with preconditioning a power converter at810. As one example, preconditioning a battery string may include obtaining state of charge, temperature, voltage, state of health, or other status information for the battery modules within the battery string, balancing the battery modules within the battery string, or any combination thereof. Based on preconditioning the battery string, for example, the PE-based BMS may ensure the battery string is in a condition to begin discharging or charging. At820, which in some cases may occur after one or more operations described with reference to810or815, the PE-based BMS may begin operating the power converter and battery string. For example, the PE-based BMS may close a contactor and begin operating one or more switches of the power converter as described herein (e.g., either directly or by way of a supplemental controller665as described with reference toFIG.6), so that power may flow through the power converter to charge or discharge a battery string, and so that the power converter may convert between an input voltage and an output voltage. At825, which in some cases may occur after beginning to operate the power converter at820, the PE-based BMS may continue operating the power converter and battery string in accordance with commands (e.g., charge or discharge commands) that may be received from an EMS. The PE-based BMS may also exchange any other signaling (e.g., send any status information) to the EMS as described herein. It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined. Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed by a controller, which may for example and without limitation refer to a processor, a microprocessor, a microcontroller, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform one or more of the related functions described herein. A controller may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). The functions described herein may be implemented in hardware, software executed by a controller, firmware executed by a controller, or any combination thereof. If implemented in software or firmware executed by a controller, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a controller, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label. The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples. The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein. | 67,751 |
11863006 | DETAILED DESCRIPTION Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings indicate the same or similar elements unless otherwise indicated. The following described exemplary embodiments do not represent all embodiments consistent with the present disclosure. Rather, they are merely examples of devices consistent with some aspects of the disclosure as detailed in the appended claims. In embodiments of the disclosure, provided is a method for determining a charging circuit. The method is applicable for a scenario of designing a charging circuit in an electronic device. FIG.1illustrates a flowchart of a method for determining a charging circuit according to some embodiments. The method for determining a charging circuit includes action11to action15. In action11, a preset equivalent circuit model is acquired. The equivalent circuit model includes a predetermined number of charging paths, and one or more of the preset number of charging paths includes a controllable device. In the embodiment, a preset equivalent circuit model may be stored in the electronic device. The equivalent circuit model may cover charging circuits of various usage scenarios. In an example, the equivalent circuit model includes two 2:1 charge pump circuits and a power management integrated circuit (PMIC). The two 2:1 charge pump circuits are a master charge pump circuit and a slave charge pump circuit respectively. In the related art, two 2:1 charge pump circuits and a PMIC may be arranged as follows: (1) A structure including a mainboard and a secondary board. The PMIC and the master charge pump circuit are provided on the mainboard and the slave charge pump circuit is provided on the secondary board. In the related art, an equivalent circuit model needs to be built for such a circuit structure, as illustrated inFIG.2. (2) An L-shaped structure. The PMIC, the master charge pump circuit, and the slave charge pump circuit are all provided on the mainboard, and the master charge pump circuit and the slave charge pump circuit share an over-voltage protection (OVP) circuit. In the related art, an equivalent circuit model needs to be built for such a circuit structure, as illustrated inFIG.3. (3) An L-shaped structure. The PMIC circuit, the master charge pump circuit, and the slave charge pump circuit are all provided on the mainboard, and each of the PMIC circuit, the master charge pump circuit, and the slave charge pump circuit is provided with a respective OVP circuit. In the related art, an equivalent circuit model needs to be built for such a circuit structure, as illustrated inFIG.4. Described here are merely three equivalent circuit models corresponding to the case where two charge pump circuits are used in the related art. Through analysis of the above circuits, it can be seen that it is very cumbersome to obtain the above three equivalent circuit models, and the calculation amount is large. Therefore, the above equivalent circuit models are normalized in the embodiment to obtain one preset equivalent circuit model, as illustrated inFIG.5. It is to be noted that equivalent devices inFIG.2andFIG.3may correspond to devices in actual circuits. For example, Z1denotes path impedance. Z2denotes equivalent impedance of a slave charge pump, impedance of a slave flexible printed circuit (FPC) of a battery and impedance of a battery connector. Z3denotes path impedance. Z4denotes equivalent impedance of a master charge pump and path impedance. Z5denotes equivalent impedance of a PMIC. Z6denotes impedance of a field effect transistor (FET) and path impedance. Z7denotes impedance of a master FPC of the battery and impedance of the battery connector. Z8denotes path impedance and impedance of an OVP circuit. Z9denotes impedance of a controllable device. Z10denotes impedance of a controllable device. Z11denotes path impedance, impedance of an OVP circuit and impedance of an FPC. Z12denotes TYPE-C interface impedance, path impedance, connection impedance, FPC impedance and connector impedance. Z13denotes impedance of a pulse code modulation (PCM) board of the battery. It will be appreciated that the equivalent devices Z1˜Z14are illustrative only and may be adjusted accordingly with the actual circuit layout of the electronic device. As illustrated inFIG.5, on the basis of the equivalent circuit model illustrated inFIG.2, an equivalent device Z9is added between the equivalent device Z1and the equivalent device Z3in the embodiment. Here, equivalent devices Z9and Z10are provided as controllable devices, such as controllable switches or controllable resistors. In the embodiment, the electronic device may control an operating state of each controllable device. The operating state may include an ON state and an OFF state. In the ON state, the controllable device may be a non-zero resistor. In the OFF state, the resistance of the controllable device is infinite. In this example, by controlling the controllable device, the equivalent circuit model can be formed into initial equivalent circuits each containing different charging paths. For example, by assigning infinity (e.g., 9999999999) to the resistance value of the controllable resistor Z9, which may be understood as removing the controllable resistor Z9inFIG.5, a first initial equivalent circuit may be obtained. The first initial equivalent circuit may be as illustrated inFIG.2. That is, the first initial equivalent circuit refers to an equivalent circuit corresponding to the case where the PMIC and the master charge pump circuit are provided on the mainboard and the slave charge pump circuit is provided on the secondary board. For another example, by assigning infinity (e.g., 9999999999) to the resistance value of the controllable resistor Z10, which may be understood as removing the controllable resistor Z10inFIG.5, a second initial equivalent circuit may be obtained. The second initial equivalent circuit may be as illustrated inFIG.3. That is, the second initial equivalent circuit refers to an equivalent circuit corresponding to the case where the PMIC, the master charge pump circuit, and the slave charge pump circuit are all provided on the mainboard and the master charge pump circuit and the slave charge pump circuit share an OVP circuit. For another example, by assigning infinity (e.g., 9999999999) to the resistance values of the controllable resistors Z9and Z10, a third initial equivalent circuit may be obtained. The third initial equivalent circuit may be as illustrated inFIG.4. That is, the third initial equivalent circuit refers to an equivalent circuit corresponding to the case where the PMIC, the master charge pump circuit, and the slave charge pump circuit are all provided on the mainboard, and each of the PMIC, the master charge pump circuit, and the slave charge pump circuit is provided with a respective OVP circuit. In the embodiment, by controlling the controllable devices in the equivalent circuit model, the equivalent circuit model is enabled to generate different initial equivalent circuits, which can cover different circuit structures in the related art. That is, initial equivalent circuits corresponding to different circuit structures can be obtained by one modeling process in the embodiment. The time taken for scheme designing is reduced, and the calculation amount of equivalent models can be reduced. It should be noted that, a scenario where two charge pump circuits are provided is illustrated as an example in the aboveFIG.5and the embodiments thereof. In practical application, an equivalent circuit model and an equivalent device serving as a controllable device in the equivalent circuit model may be adjusted according to the number of charge pump circuits, to achieve the effect that the equivalent circuit model can be adjusted by the controllable device. A phase change scheme falls within the protection scope of the present disclosure. It should be noted that, considering the operation principle of the 2:1 charge pump circuit, preset transformation is performed on each 2:1 charge pump circuit in the equivalent circuit model in the embodiment. The preset transformation includes the following: A voltage of the pre-stage circuit of the charge pump circuit is transformed to be 50% of that before the preset transformation is performed. A current of the pre-stage circuit of the charge pump circuit is transformed to be twice of that before the preset transformation is performed. A resistance of the pre-stage circuit of the charge pump circuit is transformed to be 25% of that before the preset transformation is performed. Referring toFIG.6andFIG.7,FIG.6illustrates a 2:1 charge pump circuit, a pre-stage circuit and a post-stage circuit, andFIG.7illustrates preset transformation of the 2:1 charge pump circuit to obtain an equivalent circuit of the pre-stage circuit on the post-stage. By comparingFIG.6toFIG.7, it can be seen that after the preset transformation, in the equivalent circuit of the 2:1 charge pump circuit, the input voltage Uin becomes 0.5Uin, the input current Iin becomes 2Iin, and the resistance Zin of the pre-stage circuit becomes 0.25Zin. It should be noted that the 2:1 charge pump circuit is considered to be an ideal device having no heat loss during the preset transformation. In practical applications, the 2:1 charge pump circuit has heat loss. With continued reference toFIG.6andFIG.7, it is assumed that Iin=1 amps, Iout=2 amps, Zin=4 ohms, Zout=1 ohms. Before the preset transformation, the input voltage and the input current of the pre-stage circuit are 13.2V and 1A respectively, and the output voltage and the output current of the pre-stage circuit are 9.2V and 1A respectively. The input voltage and input current of the 2:1 charge pump circuit are 9.2V and 1A respectively, and the output voltage and output current of the 2:1 charge pump circuit are 4.5V and 2A respectively. The input voltage and input current of the post-stage circuit are 4.5V and 2A respectively, and the output voltage and output current of the post-stage circuit are 2.5V and 2A respectively. After the preset transformation, the input voltage and the input current of the pre-stage circuit are 6.6V and 2A respectively, and the output voltage and the output current of the pre-stage circuit are 4.6V and 2A respectively. The input voltage and input current of the 2:1 charge pump circuit are 4.6V and 2A respectively, and the output voltage and output current of the 2:1 charge pump circuit are 4.5V and 2A respectively. The input voltage and input current of the post-stage circuit are 4.5V and 2A respectively, and the output voltage and output current of the post-stage circuit are 2.5V and 2A respectively. The calculation procedure is as follows: The resistance value of the pre-stage circuit is: Zin′=(6.6V−4.6V)/2A=1 ohm=0.25Zin. The resistance of the equivalent circuit of the 2:1 charge pump is Zeq=(4.6V−4.5V)/2A=0.05 ohm. Before the preset transformation: Iin=0.5*Iout=1A. Uin=(Uout+Iout*Zeq)*2=(4.5V+2*0.05V)*2=9.6V. Uusb=Uin+Iin*Zin=9.6V+1*4V=13.6V. After the preset transformation: Iin′=2Iin=2*0.5*Iout=Iout=2A, that is, the current before and after the resistance is equal. Uin′=0.5*Uin=0.5*(Uout+Iout*Zeq)*2=Uout+Iout*Zeq=4.6V. Zin′=(Uusb′−Uin′)/Iin′=0.5*(Uusb−Uin)/2*Iin=0.25Zin. As can be seen from the above calculation, the circuit parameters before the transformation are equivalent to the circuit parameters after the transformation in the embodiment. That is, the preset transformation is correct. In action12, an operating state of each controllable device is controlled to obtain initial equivalent circuits. Each of the initial equivalent circuits includes respective different charging paths. Description is continued with the example that 2 charge pumps are provided. In the embodiment, the first initial equivalent circuit, the second initial equivalent circuit, and the third initial equivalent circuit can be obtained respectively by controlling the controllable devices Z9and Z10. For a specific method of control, reference may be made to the contents in action11, and details will not be described herein. In action13, a charging current in each charging path of each of the initial equivalent circuits in a charging state is acquired. In the embodiment, the electronic device can acquire the charging current in each charging path of each initial equivalent circuit in the charging state. In this case, the PMIC in the initial equivalent circuit operates in a BUCK mode. With the example of solving the charging currents of the first initial equivalent circuit, MATLAB software is used to make calculation: >>syms Z1Z2Z3Z4Z5Z6Z7Z8Z9Z10Z11VBATIb Is I1I2I3I4IBAT; >>eqns3=[Z1*(I3+Ib)+Z2*I3==Z3*(I2+Ib)+Z4*I2+Z7*(I1+I2)+Z9*I6, Z3*(I2+Ib)+Z4*I2+Z10*I5==Z5*(I1+Is)+Z6*I1, Z8*(I3+Ib+I4)+Z9*I6==Z11*(I1+I5+Is)+Z10*I5, IBAT==I1+I2+I3];//Z9 is infinite; >>vars=[I1I2I3I4]; where Ib is the leakage current of the charger, and Is is the current corresponding to system power consumption. With the example of solving the charging currents of the first initial equivalent circuit, MATLAB software is used to make calculation: Z3*(I2+Ib)+Z4*I2+Z10*I5==Z5*(I1+Is)+Z6*I1″, replaced with (VBAT+DU)*I6*EQ==VBAT*(I1+Is);//EQ is the buck working efficiency and is a known variable. In this way, the charging current in each charging path, or the current at the input terminal and the output terminal of each equivalent device can be obtained in the embodiment. In action14, for each of the initial equivalent circuits, a heat loss value of the initial equivalent circuit is acquired based on the charging current in each charging path of the initial equivalent circuit and a resistance value of each equivalent device in the equivalent circuit model. In the embodiment, the electronic device may acquire the resistance value of each equivalent device in the equivalent circuit model. Then, for each equivalent device, the electronic device may calculate the heat loss value according to the input current of the equivalent device, thereby obtaining the heat loss value of each initial equivalent circuit. It should be noted that each equivalent device in the equivalent circuit model has been equivalent to a resistance in the embodiment, and therefore the operation loss value of each equivalent device can be calculated according to the formula: Q=I2*R In action15, one of the initial equivalent circuits having a minimum heat loss value under a same condition is determined as a target charging circuit. In the embodiment, a judgment condition may be preset in the electronic device. Thus, based on the judgment condition, an initial equivalent circuit may be selected from multiple initial equivalent circuits. In this example, the judgment condition may be that the output current Ibat (for charging the battery) is the same. That is, under the condition that the input current of the battery is the same, the initial equivalent circuit with the minimum heat loss value is determined as the target charging circuit. It may be understood that the target charging circuit determined in the embodiment can be used as the charging circuit of the designed electronic device, or that a charging circuit is selected from multiple initial equivalent circuits as the charging circuit of the designed electronic device. In one or more embodiments, after determining the target charging circuit, the electronic device may be further provided with a heat dissipation device. Referring toFIG.8, in action81, the electronic device may acquire the mounting position and the locating area of each equivalent device in the target charging circuit. The locating area may include a mainboard area or a secondary board area. In action82, the electronic device may acquire heat loss values of all equivalent devices in each locating area in the target charging circuit. In combination with the method of acquiring the heat loss value in action14, the heat loss value of each equivalent device can be obtained. Heat loss values of all equivalent devices in each locating area are then acquired to obtain corresponding heat loss values in the locating area. In action83, the electronic device may sort the heat loss values corresponding to the locating areas, and determine the locating area corresponding to a maximum heat loss value as the area where the heat dissipation device is to be mounted. To this end, in the embodiments of the disclosure, the operation state of each controllable device in the preset equivalent circuit model can be controlled so that the equivalent circuit model can obtain initial equivalent circuits including different charging paths. Then, the charging current in each charging path of each initial equivalent circuit in a charging state can be acquired. After that, the heat loss value of each initial equivalent circuit can be acquired according to the charging current in each charging path and the resistance value of each equivalent device in the equivalent circuit model. Finally, an initial equivalent circuit having a minimum heat loss value under the same condition may be determined as a target charging circuit. In this way, the target charging circuit can be determined by only one equivalent circuit model establishment process in the embodiment, so that the number of times of equivalent circuit model establishment and the calculation amount can be reduced. The modeling time can be shortened, and the efficiency in designing the charging circuit can be improved. On the basis of the above method for determining a charging circuit, an apparatus for determining a charging circuit is also provided in embodiments of the disclosure. As illustrated inFIG.9, the apparatus includes: a circuit model acquisition module91, an initial circuit acquisition module92, a charging current acquisition module93, a heat loss value acquisition module94and a target circuit acquisition module95. The circuit model acquisition module91is configured to acquire a preset equivalent circuit model including a preset number of charging paths. One or more of the preset number of charging paths includes a controllable device. The initial circuit acquisition module92is configured to control an operating state of each controllable device to form or obtain initial equivalent circuits. Each of the initial equivalent circuits includes respective different charging paths. The charging current acquisition module93is configured to acquire a charging current in each charging path of each of the initial equivalent circuits in a charging state. The heat loss value acquisition module94is configured to: for each of the initial equivalent circuits, acquire a heat loss value of the initial equivalent circuit based on the charging current in each charging path of the initial equivalent circuit and a resistance value of each equivalent device in the equivalent circuit model. The target circuit acquisition module95is configured to determine one of the initial equivalent circuits having a minimum heat loss value under a same condition as a target charging circuit. In one or more embodiments, the equivalent circuit model includes an equivalent circuit of a charge pump, and in the equivalent circuit model, preset transformation is performed on a pre-stage circuit of the charge pump circuit. The preset transformation includes the following: a voltage of the pre-stage circuit of the charge pump circuit is transformed to be 50% of that before the preset transformation is performed, a current of the pre-stage circuit of the charge pump circuit is transformed to be twice of that before the preset transformation is performed, and a resistance of the pre-stage circuit of the charge pump circuit is transformed to be 25% of that before the preset transformation is performed. In one or more embodiments, the equivalent circuit model includes a master charge pump circuit and a slave charge pump circuit, and further includes a power management integrated circuit (PMIC). The initial equivalent circuits include at least one of a first initial equivalent circuit, a second initial equivalent circuit, or a third initial equivalent circuit. The first initial equivalent circuit corresponds to that the PMIC and the master charge pump circuit are provided on a mainboard and the slave charge pump circuit is provided on a secondary board. The second initial equivalent circuit corresponds to that the PMIC, the master charge pump circuit and the slave charge pump circuit are all provided on the mainboard and the master charge pump circuit and the slave charge pump circuit share an OVP circuit. The third initial equivalent circuit corresponds to that the PMIC, the master charge pump circuit and the slave charge pump circuit are all provided on the mainboard, and each of the PMIC, the master charge pump circuit and the slave charge pump circuit is provided with a respective OVP circuit. In one or more embodiments, the apparatus further includes a mounting area acquisition module. The mounting area acquisition module includes: a locating area acquisition unit, a heat loss value acquisition unit, and a mounting area acquisition unit. The locating area acquisition unit is configured to acquire a mounting position and a locating area of each equivalent device in the target charging circuit. The heat loss value acquisition unit is configured to acquire a heat loss value of all equivalent devices in each locating area in the target charging circuit. The mounting area acquisition unit is configured to determine a corresponding area with a maximum heat loss value as an area for mounting a heat dissipation device. In one or more embodiments, the controllable device is a controllable resistor. When the controllable device is in a conductive state, the controllable resistor is a non-zero resistor; or when the controllable device is in an off state, a resistance value of the controllable resistor is infinite. It will be appreciated that the apparatus provided in the embodiments of the present disclosure corresponds to the above-described method. For details, reference may be made to the contents of the various embodiments of the method, and details are will not be described herein. The technical solution provided by the embodiments of the disclosure may include the following beneficial effects: As can be seen from the above embodiments, in the embodiments of the disclosure, the operation state of each controllable device in the preset equivalent circuit model can be controlled so that the equivalent circuit model can form or obtain initial equivalent circuits including different charging paths. Then, the charging current in each charging path of each initial equivalent circuit in a charging state can be acquired. After that, the heat loss value of each initial equivalent circuit can be acquired according to the charging current in each charging path and the resistance value of each equivalent device in the equivalent circuit model. Finally, an initial equivalent circuit having a minimum heat loss value under the same condition may be determined as a target charging circuit. In this way, the target charging circuit can be determined by only one equivalent circuit model establishment process in the embodiment, so that the number of times of equivalent circuit model establishment and the calculation amount can be reduced. The modeling time can be shortened, and the efficiency in designing the charging circuit can be improved. FIG.10illustrates a block diagram of an electronic device according to some embodiments. For example, the electronic device1000may be a smartphone, a computer, a digital broadcast terminal, a tablet, a medical device, exercise equipment, a personal digital assistant, or the like. Referring toFIG.10, an electronic device1000may include one or more of: a processing component1002, a memory1004, a power component1006, a multimedia component1008, an audio component1010, an input/output (I/O) interface1012, a sensor component1014, a communication component1016, and an image acquisition component1018. The processing component1002generally controls the overall operation of the electronic device1000, such as operations associated with displays, telephone calls, data communications, camera operations, and recording operations. The processing component1002may include one or more processors1020to execute a computer program. In addition, the processing component1002may include one or more modules to facilitate interaction between the processing component1002and other components. For example, the processing component1002may include a multimedia module to facilitate interaction between a multimedia component1008and the processing component1002. The memory1004is configured to store various types of data to support operation at the electronic device1000. Examples of such data include computer programs for any application or method operating on electronic device1000, contact data, phone book data, messages, pictures, video, and the like. Memory1004may be implemented by any type of volatile or non-volatile storage device or combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, a magnetic disk, or an optical disk. The power component1006provides power to various components of electronic device1000. The power component1006may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power for electronic device1000. The power component1006may include a power chip, and the controller may communicate with the power chip to control the power chip to turn on or off the switching device so that the battery may or may not supply power to the mainboard circuit. The multimedia component1008includes a screen providing an output interface between the electronic device1000and the target object. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the target object. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundary of the touch or slide action, but also detect the duration and pressure associated with the touch or slide action. The audio component1010is configured to output and/or input audio signals. For example, the audio component1010includes a microphone (MIC) configured to receive external audio signals when electronic device1000is in an operating mode, such as a call mode, a recording mode, and a speech recognition mode. The received audio signal may be further stored in the memory1004or transmitted via the communication component1016. In some embodiments, the audio component1010further includes a speaker for outputting an audio signal. The I/O interface1012provides an interface between the processing component1002and a peripheral interface module which may be a keyboard, a click wheel, a button, or the like. The sensor component1014includes one or more sensors for providing state assessment of various aspects of the electronic device1000. For example, the sensor component1014may detect an on/off state of the electronic device1000, and a relative positioning of the components, such as a display screen and a keypad of the electronic device1000. The sensor component1014may also detect a change in position of the electronic device1000or one of the components, the presence or absence of a target object in contact with the electronic device1000, an orientation or acceleration/deceleration of the electronic device1000, and a change in temperature of the electronic device1000. The communication component1016is configured to facilitate wired or wireless communication between the electronic device1000and other devices. The electronic device1000may access a communication specification based wireless network, such as WiFi, 2G, 3G, 4G, 5G, or a combination thereof. In one exemplary embodiment, the communication component1016receives broadcast signals or broadcast-related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, the communication component1016also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on Radio Frequency Identification (RFID) technology, Infrared Data Association (IrDA) technology, Ultra Wideband (UWB) technology, Bluetooth (BT) technology, and other technologies. In an exemplary embodiment, the electronic device1000may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPD), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components. In an exemplary embodiment, there is also provided a non-transitory readable storage medium including an executable computer program, such as a memory1004including instructions. The executable computer program may be executed by a processor. The readable storage medium may be a ROM, a random access memory (RAM), a compact disc read-only memory (CD-ROM), a magnetic tape, a floppy disk, an optical data storage device, or the like. Other embodiments of the disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, usages, or adaptations that follow the general principles of the disclosure and include common general knowledge or customary technical means in the art not disclosed here. The specification and embodiments are to be regarded as exemplary only, and the true scope and spirit of the disclosure subjects to only the following claims. In the description of the present disclosure, the terms “one embodiment,” “some embodiments,” “example,” “specific example,” or “some examples,” and the like can indicate a specific feature described in connection with the embodiment or example, a structure, a material or feature included in at least one embodiment or example. In the present disclosure, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, can be combined and reorganized. Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), an inter-network (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks). While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any claims, but rather as descriptions of features specific to particular implementations. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a subcombination or variation of a subcombination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. It is to be understood that the disclosure is not limited to the precise structures already described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from the scope of the disclosure. The scope of the disclosure is limited only by the appended claims. | 34,116 |
11863007 | DETAILED DESCRIPTION Inventory systems are utilized by many entities for storing and managing inventory. For example, some retailers may utilize a warehouse of racks that store inventory items in various bins. When an order for a specific inventory item needs to be filled by the retailer, an associate typically retrieves the inventory item from the bin where the inventory item is stored. Inventory systems according to one embodiment described herein may utilize hand-propelled (or manual-propelled) transport vehicles (e.g., utility carts, wheel carts, maintenance carts, etc.) to aid in transporting items to different locations within a facility. As used herein, a hand-propelled transport vehicle may be referred to herein as a transport vehicle or cart. In some example operations, the items may be retrieved from inventory, placed on a transport vehicle, and transported to a storage area in preparation for delivery. In some inventory systems, the transport vehicles may be equipped with one or more electronic devices to aid in managing inventory. For example, the transport vehicles within a facility can be equipped with light sources (e.g., light-emitting diode (LED) lights), a wireless smart controller, wireless communication devices, barcode readers/scanners, etc. These devices can be stored on the transport vehicles and used by associates (e.g., for processing) when items (or packages) are being transported via the transport vehicles. For example, an associate can use handheld or fixed barcode readers located on the transport vehicles to scan items placed on the transport vehicles for identifying information (e.g., destination ID, shipment ID, etc.). In another example, the inventory system can remotely control the light sources on a given transport vehicle via the wireless smart controller on the transport vehicle to emit different color lights, depending on an operating status of the transport vehicle. In some operations, for instance, an inventory system can use different sets of light sources on each transport vehicle to indicate a level of priority associated with the transport vehicle. For example, the inventory system can turn on the “red” light sources on a first set of transport vehicles to indicate that the first set of transport vehicles are high priority transport vehicles (e.g., the first set of transport vehicles may contain items that are due to be shipped within a first threshold amount of time). In another example, the inventory system can turn on the “yellow” light sources on a second set of transport vehicles to indicate that the second set of transport vehicles are medium priority transport vehicles (e.g., the second set of transport vehicles may contain items that are due to be shipped within a second threshold amount of time). In yet another example, the inventory system can turn on the “green” light sources on a third set of transport vehicles to indicate that the third set of transport vehicles are low priority transport vehicles (e.g., the third set of transport vehicles may contain items that are due to be shipped within a third threshold amount of time). Note, however, that this is merely an example of how an inventory system can use lighting sources on transport vehicles to aid in processing customer orders. The electronic devices on a transport vehicle are generally battery powered devices, and thus, may have to be recharged depending on, e.g., the amount of use, time since a last recharge, environmental conditions, etc. One conventional technique that is often used to recharge electronic devices involves moving the transport vehicle and/or the electronic devices to a charging station (or location) within the facility dedicated for recharging. In many situations, however, this conventional technique may not be feasible for facilities with a large number of transport vehicles and/or electronic devices (e.g., the number of available charging stations may be limited in the facility). Another conventional technique involves replacing the batteries of electronic device(s) with new (or charged) batteries. However, replacing batteries in this manner can be significantly time consuming and inefficient. Accordingly, embodiments herein describe a wheel-based generator assembly for charging electronic devices on a transport vehicle, such as a cart. In one particular embodiment described in more detail below, the wheel-based generator assembly can include an omni-directional wheel (also referred to herein as “omni wheel”), a mounting assembly/structure, a gear motor (e.g., a generator), and a voltage regulator (e.g., an alternating current (AC)/direct current (DC) to DC converter). When installed on a cart, the wheel-based generator assembly is configured to convert the mechanical motion of the cart (e.g., as it is being pushed throughout the facility) into electrical energy, which can be used to charge one or more electronic devices on the cart. By charging electronic devices in this manner, embodiments can significantly reduce the amount of time and complexity associated with conventional charging techniques. Note that while many of the following embodiments use utility carts within a fulfillment center as a reference example of a transport device in a facility in which the wheel-based charging system described herein could be implemented, embodiments are not limited to such utility carts or facilities. For example, the wheel-based charging system described herein can be used for other types of transport devices (e.g., shopping carts, grocery carts, etc.) in other types of facilities (e.g., retail stores, grocery stores, etc.). FIG.1illustrates an example inventory system100with multiple regions and carts used to transition items about the regions, according to one embodiment. The inventory system100may be arranged in a facility or warehouse (e.g., distribution facility, fulfillment center, etc.) that is logically organized into areas or regions associated with various functions. In this depicted example, the facility includes a storage region102and a pick station104. Note, however, that depending upon the size of the inventory system100, the facility may hold more than one of the storage region102and the pick station104, or the facility may be configured without the storage region102or the pick station104. Other examples of suitable facility operations may include staging at loading zones, transporting to different areas in the facility, loading off vehicles, and so forth. The inventory system100includes one or more inventory holders106and one or more (manual or hand-propelled) carts130within the storage region102and the pick station104. Note that only some of the inventory holders106are shown referenced with the number106for ease of illustration. Each inventory holder106may be implemented as a physical structure to hold various inventory items. The inventory holder106has a physical length, width, and height that may be standardized or varied within the inventory system100. In general, the inventory holders106may be configured to hold essentially any type or size of item or be used for any number of purposes, including, but not limited to, carrying pallets, storing shipping supplies, holding garbage, supporting empty boxes, supporting filled boxes with items once orders are fulfilled, and so on. Additionally, as used herein, inventory holders106can include holders for other types of products or items and hence include order holders. The pick station104is designed with multiple locations120to accommodate one or more inventory holders106. In the depicted example, a line of three pick locations120is shown next to a set of inventory holders106. Here, items from one or more of the pick locations120may be transferred into one of the inventory holders106, and vice versa. In another example, items from one or more of the pick locations120and/or the inventory holders106can be transferred onto the cart130, and vice versa. Note, however, the depicted storage region102and pick station104are merely representative, and that the storage region102and/or the pick station104may have a different configuration and/or different number of inventory holders106. The carts130are manual or hand-propelled transport devices that can move about the facility, e.g., under the direction of an associate. The carts130may be used at various times to transport items from the inventory holders106around the facility among the regions. For example, one or more carts130can be used to transport items from inventory holders106between the storage region102and the pick station104. As shown inFIG.1, four carts130are located in the storage region102, two of which are being pushed down aisles between sets of inventory holders106and another two of which are stationary. Similarly, as shown inFIG.1, a single cart130is being pushed within the pick station104. Each cart130includes a set of wheels134, one or more (electronic) cart devices136, and one or more batteries146(e.g., for the cart devices136). Each cart130can be used to transport one or more items132throughout a facility. For example, each cart130includes a cart frame that provides one or more surface layers/levels for holding/storing various items132. The set of wheels134generally allow the cart device136to be pushed or moved in any direction. In one embodiment, for example, the set of wheels134can include a set of swivel caster wheels, which allow the cart130to move in all directions. The cart130can include any number of wheels134(e.g., one, two, three, four, etc.). The cart devices136are representative of a variety of electronic devices, which can be used to aid management of operations in the inventory system100. Examples of such devices136can include, but are not limited to, communication devices (e.g., smartphones, tablets, laptops, etc.), wireless controllers, light sources (e.g., LEDs), barcode readers/scanners, etc. In one embodiment, the cart devices136can include a smart (wireless) controller that interacts with and communicates with the management system110to control other cart devices136on the cart130. For example, the smart controller can receive commands from the management system110to turn on/off electronic devices, exchange data with the management system110, and the like. Additionally or alternatively, in some embodiments, the cart devices136can include different sets of light sources (e.g., different sets/colors of LED lights). In this embodiment, the smart controller can be configured to control the different sets of light sources, based on commands/instructions received via the management system110. For example, the smart controller on a cart130may be configured to turn on a set of “green” LEDs on the cart130to indicate that the cart130has a low priority status, turn on a set of “yellow” LEDs on the cart130to indicate that the cart130has a medium priority status, turn on a set of “red” LEDs on the cart130to indicate that the cart130has a high priority status, and so on. Apart from indicating a priority status, the smart controller can be configured to generate and send electronic notifications to the management system110to indicate, e.g., that assistance with the cart130is needed, a malfunction has occurred, etc. Each cart device136can be powered by one or more rechargeable batteries (also referred to herein as battery packs)146that are on the cart130. To avoid the need for manual battery recharging (e.g., by plugging the batteries146into a charging bay, replacing the batteries146, etc.), each cart130can be equipped with a wheel-based charging system138(also referred to herein as a wheel-based generator assembly). The wheel-based charging system138is coupled to the batteries146and leverages the motion of the cart130(e.g., as the cart130is being pushed throughout a facility) to recharge the batteries146. For example, as the cart130is pushed throughout the facility, the wheel-based charging system138translates the mechanical energy of the motion of the cart130into electrical energy, charging the batteries146. The wheel-based charging system138can be installed onto a bottom or side surface of the cart130. The wheel-based charging system138includes a wheel140, a motor142, and a (voltage) regulator148. In one embodiment, the wheel140is an omni wheel that is attached to a bottom surface of the cart130and makes contact with the floor. As used herein, an omni wheel refers to a wheel with multiple small discs (or rollers) around the circumference of the wheel which are perpendicular to the turning direction. The omni-wheel enables the wheel-based charging system138to move in all directions (e.g., forwards, backwards, laterally, etc.) with the cart130. Additionally, the omni-wheel can provide charging for the electronic devices136bi-directionally (e.g., as the omni-wheel rotates forward and reverse). This allows the wheel-based charging system138to generate power to charge the batteries146as the cart is pushed in multiple directions (e.g., forwards and backwards). The wheel140is coupled to the motor142. In one embodiment, the motor142is a DC gear motor with a rotatable shaft. The motor142can be configured to operate as a generator, e.g., by driving or rotating the shaft of the motor142via the wheel140. When operated as a generator, the motor142converts the mechanical energy of the driven shaft into electrical energy, which is used to charge the batteries146. In some embodiments, the regulator148can be used to control (e.g., regulate) the output voltage and polarity of the motor142, e.g., as the omni-wheel rotates in different (forward/backward) directions. In one embodiment, the regulator148is an AC/DC to DC converter. In this manner, the wheel-based charging system138can use the motion of the cart130within the facility to recharge batteries146for one or more cart devices136. Note that althoughFIG.1depicts the cart130with a single wheel-based charging system138, in some embodiments, the cart130can include multiple wheel-based charging systems138. In these embodiments, a first wheel-based charging system138can be attached to a first side of the cart and a second wheel-based charging system138can be attached to a second side of the cart, such that the wheels140of the respective first and second wheel-based charging systems138are orthogonal with respect to each other. Equipping a cart130with multiple wheel-based charging systems138in this manner can enable the wheel-based charging systems138to generate power to charge the batteries146in any direction that the cart130is pushed. FIG.2illustrates an example cart130equipped with a wheel-based charging system138, according to one embodiment. Although in this example, the cart130is depicted with four wheels134, the cart130can include any number of wheels134. Similarly, while the cart130is shown with a cart frame that provides two levels/layers for holding and transporting items, in other examples, the cart130can include any number of levels/layers (e.g., a single level/layer, three levels/layers, etc.). In general, the cart130can have a variety of different configurations and/or be formed from a variety of materials (e.g., metal, plastic, wood, etc.) suitable for holding one or more items. For example, the top layer and/or bottom layer of the cart130can have a surface shape that is substantially planar, crowned, domed, irregular, or any other shape or combination of shapes. In another example, a first set of the carts130within the facility may have different clearances (e.g., from the ground) than a second set of the carts130. As noted, the cart130is manually propelled (e.g., by pushing, by pulling, etc.) and can be moved around in any direction, via the wheels134. The wheels134are typically load-bearing wheels, which support the weight of items that are transported via the cart130. The wheel-based charging system138can be mounted to a bottom surface or side surface of the cart130via a mounting structure/assembly. In one embodiment, the mounting structure is formed by a support member202, a support member204, and a spring244. As shown inFIG.2, for example, the support member202, the support member204, and spring244form a triangular mounting structure. In one embodiment, the support members202and204are hinged (metal) beams that allow for mounting the wheel-based charging system138underneath the cart130(e.g., as depicted inFIG.2) or to a side of the cart130(not shown). In one embodiment, the spring244acts as shock absorber, which provides a flexible mounting clearance for the wheel-based charging system138for carts of various sizes. Additionally, the spring244is used to press the wheel140against the floor, while the cart130is pushed across the floor. For example, the spring244can be configured to provide a force sufficient to keep the wheel140pressed against the floor, while the cart130is pushed across the floor. The wheel140of the wheel-based charging system138may be a non-loading bearing wheel of the cart130. Note thatFIG.2depicts merely a reference example of how the wheel-based charging system138can be attached to the cart130and that the wheel-based charging system138can be attached to the cart130in other locations. For example, whileFIG.2depicts the wheel-based charging system138located at a front side of the cart130, in some embodiments, the wheel-based charging system138can be located at the back side of the cart130, left side of the cart130, or right side of the cart130.FIG.3, for example, illustrates a cart130equipped with a wheel-based charging system130that is located at the back side of the cart130, according to one embodiment. Compared to the wheel140of the wheel-based charging system130depicted inFIG.2, here inFIG.3, the wheel140of the wheel-based charging system130is not located underneath the bottom side of the cart130. In this manner, the wheel-based charging system138can be flexibly attached to the cart130at different locations of the cart130to accommodate different cart configurations, facility configurations, etc. In some embodiments, instead of using an additional wheel140, the wheel-based charging system138can be configured to use one of the wheels134instead. For example, in this embodiment, the shaft of the motor142can be coupled to one of the wheels134, such that the rotation of the wheel134drives the shaft of the motor142, generating electrical energy. Similarly, in this embodiment, the regulator148can be used to regulate the voltage output and polarity of the motor142. In some embodiments, the cart130can be equipped with multiple wheel-based charging systems138, each using a separate wheel140to charge the batteries146.FIG.4illustrates an example cart130equipped with two wheel-based charging systems138A and138B, according to one embodiment. Here, the wheel-based charging system138A includes a (omni) wheel140A and the wheel-based charging system138B includes a (omni) wheel140B. In some embodiments, the wheel-based charging systems138A and138B can be mounted to the cart130at different locations so that the wheels140A and140B are orthogonal with respect to each other. Here, for example, the wheel-based charging system138B is located at a front side of the cart130and the wheel-based charging system138A is located at an adjacent side of the cart130, so that the wheels140A and140B are orthogonal with respect to each other. The wheel-based charging systems138A and138B can include respective first and second motors142coupled to the respective wheels140A and140B for converting the mechanical motion of the respective wheel into electrical energy. In addition, a first regulator148can be coupled to the first motor142to control an output voltage of the first motor142and/or polarity of the output voltage of the first motor142, and a second regulator148can be coupled to the second motor142to control an output voltage of the second motor142and/or polarity of the output voltage of the second motor142. As noted, with multiple wheel-based charging systems configured in this manner, embodiments can provide charging for the batteries146in any direction that the cart130is moved. FIG.5illustrates another example cart130equipped with a wheel-based charging system138, according to one embodiment. Compared to the wheel-based charging system depicted inFIG.2, in this embodiment, the wheel-based charging system138is mounted to a front side of the cart130(e.g., as opposed to underneath the cart130). Additionally, in this embodiment, the wheel140is positioned in front of the cart130(e.g., relative to the front side of the cart130). Further, in this embodiment, a plowing mechanism504is coupled to the wheel140via a support member502. The plowing mechanism504is configured to clear debris (e.g., dust, paper, trash, etc.) that may be on the floor of the facility to reduce the amount of debris encountered by the wheel140. Note that the plowing mechanism504depicted inFIG.5is merely an example. In general, the plowing mechanism504can have a variety of different configurations/shapes and/or be formed from a variety of materials (e.g., metal, plastic, etc.) suitable for clearing debris and other articles from the floor. FIGS.6A-6Cillustrate different views of an example wheel-based charging system138, according to one embodiment. In particular,FIG.6Ashows a side view of the wheel-based charging system138,FIG.6Bshows a back view of the wheel-based charging system138, andFIG.6Cshows another side view of the wheel-based charging system138. In this embodiment, the wheel-based charging system138includes the support member202, the support member204, the spring244, the wheel140, the motor142, and the regulator148. The support members202and204may have a variety of shapes and/or configurations suitable for mounting or installing the wheel-based charging system138to the cart130. For example, in one embodiment, the support members202and204are C-shaped metal beams. The C-shaped metal beams allow for mounting the wheel-based charging system138to different sides of the cart130. Here, for example, the support member202is mounted to an inner side of the cart130(e.g., via screws, bolts, etc.) at the bottom layer/level of the cart130. In other embodiments, the support member202can be mounted to a bottom surface of the cart130, an outer side of the cart130, etc. Note that although the support members202and204are depicted with cutouts, in other embodiments, the support members202and204may include a fewer amount (or no amount) of cutouts. The support member202and the support member204are hinged support members (e.g., they are connected at a hinge602via screws, bolts, etc.). The hinge602is located at ends of the support member202and the support member204. The opposite end of the support member202(e.g., the end opposite the hinge602) is coupled to the spring244at an (first) end of the spring244, and the opposite end of the support member204(e.g., the end opposite the hinge602) is coupled to the spring244at an (second) opposite end of the spring244. This particular configuration of the support members202,204and the spring244forms a triangular mounting structure. For example, in this triangular structure, the spring244acts as a shock absorber, providing sufficient clearance for mounting the wheel-based charging system138to carts130of various sizes, while also providing sufficient force to keep the wheel140pressed against the floor. The wheel140is coupled to the support member204at an opposite end of the support member from the hinge602and on one side of the wheel140. Additionally, the motor142is coupled to the wheel140on this same side of the wheel140. In particular, as shown inFIG.6B, the wheel140is coupled to a rotatable shaft604of the motor142. Here, the motor142is driven by the wheel140to generate electricity. For example, the wheel140is capable of rotating in two directions (e.g., bi-directionally) in order to drive the motor142. Further, by using an omni wheel for the wheel140, the wheel140adds minimal friction when the cart130moves in orthogonal directions. As shown inFIG.6A, the regulator148is attached to the support member204on one side of the support member proximal to the end of the support member that is coupled to the spring244. Note, however, that the regulator148can be located elsewhere on the wheel-based charging system138, such as on the support member202, a different location on the support member204, on the cart130, etc. It should be noted that the wheel-based charging system138depicted inFIGS.6A-6Cis merely a reference example of a wheel-based charging system that can be attached or installed on a cart130. In other embodiments, the wheel-based charging system138can have other configurations.FIG.7, for example, illustrates another wheel-based charging system138that can be installed on cart130, according to one embodiment. InFIG.7, the wheel-based charging system138includes a wheel fork702which is connected to a wheel140. The wheel140is coupled to a motor142on one side of the wheel140and to a spring244on an opposite side of the wheel140. Further, while a regulator148is not shown inFIG.7, in some embodiments, a regulator148can be coupled to an output of the motor142. The wheel fork702provides a mounting structure for the wheel-based charging system138. For example, the wheel fork702can be attached to the cart130(e.g., at the bottom, side, etc.) at one end of the wheel fork702and the other end of the wheel fork702can be attached to the wheel140. As shown, a first spring244A is coupled to one prong of the wheel fork702and a second spring244B is coupled to another prong of the wheel fork702. The wheel fork702can provide sufficient force, via springs244A and244B, for keeping the wheel140pressed against the floor, such that the wheel140rotates when the cart130is pushed. The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. In the preceding, reference is made to embodiments presented in this disclosure. However, the scope of the present disclosure is not limited to specific described embodiments. Instead, any combination of the features and elements described herein, whether related to different embodiments or not, is contemplated to implement and practice contemplated embodiments. Furthermore, although embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the scope of the present disclosure. Thus, the aspects, features, embodiments and advantages described herein are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the invention” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). Aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. | 35,096 |
11863008 | DETAILED DESCRIPTION As will become appreciated from the following discussion, the instant disclosure provides embodiments that support powering one or more loads in a shared manner between a driveline and a PTO (PTO) device, and/or replaces one or more aspects of previously known vehicle electrical systems and/or belt driven powering interfaces for devices. While the disclosure throughout contemplates using the apparatus, system, and process disclosed to drive an auxiliary load, for clarity of description, one or more specific loads such as an HVAC, mixer, and/or hydraulic pump may be referenced in certain examples. All references to specific load examples throughout the present disclosure are understood to include any load that can be powered electrically and/or with a rotating shaft. Further, while the disclosure throughout contemplates using the apparatus, system, and process disclosed as coupled with a motive load, for simplicity the description herein may refer to the motive load as a driveline and/or as a wheeled system. All references to specific motive loads throughout this disclosure should also be understood to be references to any motive load and/or portion of a driveline between a prime mover and a final motive engagement (e.g., wheels, tracks, etc.) In an example, in commercial long-haul class 8 vehicles, commonly referred to as “18-wheeler sleeper cabs”, traditionally a front-end accessory drive (FEAD) powers accessory components such as the electrical charging system (e.g., the alternator), the compressor that drives the HVAC air conditioner, fans, power steering, air compressors, fluid pumps, and/or other accessory loads depending upon the specific implementation. Historically, operators of such vehicles would run the engine nearly all the time including while driving for propulsion and idling while stopped to maintain the accessory functions such as “hotel loads” including lights, television, refrigerator, personal devices (e.g., a CPAP, electronic device charging, etc.), and HVAC cooling in summer months. In an effort to improve fuel economy and/or reduce emissions, fleet policy and laws in many locations prohibit idling for extended periods of time. Many solutions to provide the required electricity and cooling have been commercialized, including the addition of a small engine for that function (APU), addition of batteries that run an electrical air conditioner that are charged while driving, utilization of locations that have shore power available, and/or periodic cycling of the engine. Previously known systems have followed two paths for engine off air conditioning. In a first implementation, the existing belt driven compressor is used while driving and a second electrically driven compressor is used while the engine is off. Such a solution adds cost and complexity. In a second implementation, a purely electrically driven compressor is operated for all of the HVAC demand. The disadvantage of a full-time electric HVAC system are two-fold: First, the increase in power demand exceeds the available power in 12V systems driving the industry to higher system voltage (especially 48V). Secondly, the system efficiency suffers when the engine shaft power is converted to electricity then converted back to shaft power to drive the compressor while driving. References throughout the present disclosure to any particular voltage level should be understood to include both nominal voltages (e.g., a 12V battery) and actual system voltages. For example, a nominal 12V lead-acid battery typically operates at 14V or 14.5V during operations where the battery is in electrical communication with a charging device such as an alternator. Further, a nominal 12V battery may operate below 12V during discharge operations such as during cranking, and may be as low as 10.5V during certain operations. Further still, while certain voltages are described herein for clarity of description and due to ordinary terminology in industry (e.g., 12V, 48V, etc.), it will be understood that the features of the present disclosure are applicable to a wide range of voltages, and the specific voltages described are not limiting. For example, a nominal 48V system may be 56V or 58V during certain operations of a system, or as low as 42V during other operations of the system. Additionally, without limitation, features and operations for a nominal 48V system may be applicable to a nominal 12V system and/or a 24V. In certain examples, as will be understood to one of skill in the art having the benefit of the present disclosure, some voltage ranges may change the operating principles of a system, such as a high voltage system (e.g., more than 60V) that may require additional aspects to certain embodiments such as an isolated ground, and/or a low voltage system where a high power requirement may limit the practicality of such systems. The voltage at which other system effects may drive certain considerations depends upon the specific system and other criteria relating to the system that will be understood to one of skill in the art having the benefit of the present disclosure. Certain considerations for determining what range of voltages may apply to certain example include, without limitation, the available voltages of systems and accessories on a specific vehicle, the regulatory or policy environment of a specific application, the PTO capability of available driveline components to be interfaced with, the time and power requirements for offline power, the availability of regenerative power operations, the commercial trade-offs between capital investment and operating costs for a specific vehicle, fleet, or operator, and/or the operating duty cycle of a specific vehicle. The present disclosure relates to PTO devices having a motor/generator, where the PTO device is capable to selectively transfer power with the driveline, such as at a transmission interface. In embodiments, a 48V PTO may replace the traditional engine mounted, belt driven alternator, HVAC compressor, and/or the flywheel mounted brush starter with a transmission PTO mounted electrical machine on a common shaft with the HVAC compressor. The disclosed PTO device accessories on the transmission enable several modes of operation, independent of engine speed, using proven parts such as simple planetary gears and shift actuators. Without limitation, example PTO devices disclosed herein allow for operating the load (e.g., an HVAC compressor) with the same electric machine used to charge the battery while driving and/or during engine-off operations such as sleeping, hoteling, or waiting (e.g., at a loading dock, construction site, or work site), and the ability to operate the charging and load mechanically from the driveline (e.g., during coasting or motoring). In certain embodiments, an example PTO system reduces total ownership costs and/or enhances the ability to meet anti-idling requirements while allowing the operator to maintain climate control or other offline operations. An example system also improves system economics for the vehicle manufacturer, fleet, owner, or operator, by reducing green-house gas (GHG) emissions, improving fuel economy, improving operator comfort and/or satisfaction, and enabling original equipment manufacturer (OEM) sales of various feature capabilities supported by the PTO system. Certain example systems disclosed herein have a lower initial cost than previously known systems (e.g., diesel or battery APUs and/or redundant HVAC systems) while providing lower operating costs and greater capability. In embodiments, a PTO device can be mounted to a driveline, such as a transmission. A power system can be charged, for example, a lead battery. Then, the power system can be utilized to power a device such as an HVAC system via the PTO device. Also, the power system can be utilized during start-up of an affiliated engine or vehicle prime mover. In one example, a 48V PTO enables “anti-idle” technologies, such as no-idle hoteling with an e-driven AC compressor. Such an arrangement reduces green-house gasses when, for example, a sleeper cab of a long-haul tractor is placed in a hotel mode. However, the PTO is not limited to such a vehicle and the PTO can be applied to other vehicles. Engine-off operations such as coasting or motoring can be used to regeneratively charge the 48V power system and/or mechanically power a shared load. Electricity can be routed to assist power steering during engine-off operations. Other aspects of engine-off operations, intelligent charging, electrical HVAC, and/or stop/start modes complement the disclosed PTO device. The PTO device improves fuel economy by converting otherwise wasted energy to usable electricity and achieves a reduction in green houses gases. The design can eliminate other engine-mounted components to reduce vehicle weight and integration costs, and to reduce the engine system footprint. For example, it is possible to utilize a PTO device in lieu of one or more of a traditional alternator, starter, and/or AC compressor. In certain embodiments, redundant systems can also be eliminated. For example, some previously known systems include a first circuit relying on the engine for power to evaporative circuits and the air conditioning. Then, a second system is mounted for engine-off operations, which second system also includes an evaporation circuit and an air conditioning circuit. In another example, the alternator port and AC compressor port can be removed from the engine, allowing for a reduction in component and integration costs, and reducing parasitic loads on the engine. In certain embodiments, aspects of a starter can be omitted, for example where the PTO device is utilized to start the engine. The auxiliary drive aspect of the PTO device can couple to the evaporator circuits and the air conditioner. In an example, the air conditioner does not couple through the engine, but through the PTO device. When needed, the AC compressor and electric alternator can be moved from engine-mounted to mounting on the PTO device, which may be mounted to an interface on the transmission. An example auxiliary drive includes the air conditioner (AC) and/or other powered electrical systems. Regenerated coasting energy can be captured via the motor/generator coupled to the driveline, and later utilized to power electrical loads on the vehicle. An example system includes managed lead acid batteries. The electrical system can include an air-cooled system. An example PTO device includes a motor/generator having a motor rating of 5 kW continuous output and 10 kW peak output. The motor can be used as part of the motor/generator. Various motor types are compatible with the disclosure, including permanent magnet type, wire-wound synchronous type, and induction motor type. External excitation can be applied to the wire-wound synchronous type motor. Other components can include a housing or other adapter for the PTO device, gearing to couple to the transmission or other driveline component to the PTO device, gearing to step up or down between the motor/generator, auxiliary drive, and/or transmission or driveline. An example PTO device includes a gear change actuator such as a gear selector, an inverter, a converter, and/or an electric steering circuit. The disclosed PTO device variants provide numerous benefits, including in certain embodiments: capturing motive energy that would be otherwise lost, prime mover stop/start mode operation, intelligent charging, reduced system and system integration costs, and fuel savings. Certain embodiments include fewer engine-mounted components, reducing the engine footprint, and improving driver visibility around the engine via reductions in the mounting space. Certain embodiments provide for a reduced load on the serpentine belt. Certain embodiments provide for higher system power within the same footprint, and/or for greater utilization of system power and reduced overdesign of power to support variability in applications and duty cycles. Referring toFIG.1, an embodiment functional block diagram is provided for a PTO device configured with a prime mover102(e.g., an internal combustion engine) coupled with a transmission104. An electronic control unit (ECU)122may provide control functions to the prime mover102and a transmission control unit (TCU)120may provide control functions to the transmission104. In embodiments, the PTO device may include a motor/generator (M/G)112and a load110(e.g., an HVAC system) drivingly coupled by a gear box108that is further drivingly coupled to the transmission104through the PTO device106. The motor/generator112is provided drive and control signals from a motor drive converter (MDC)114that is powered by a battery assembly116(e.g., with 48 v and 12 v supply voltages). The battery assembly116may be managed by a battery management system (BMS)118. The description including various controllers122,120,114is a non-limiting example, and control functions of a system may be distributed in any manner. In certain embodiments, control functions described throughout the present disclosure may be present in an engine controller, transmission controller, vehicle controller (not shown), a motor drive controller114, and/or distributed among various devices. In certain embodiments, control functions described throughout the present disclosure may be performed, at least in part, in a separate controller remote from the vehicle—for example from a controller at least intermittently in communication with the vehicle, in a service tool, in a manufacturing tool, and/or on a personal device (e.g., of an operator, owner, fleet personnel, etc.). With reference toFIG.2, an example system202constructed in accordance to one example of the present disclosure is schematically depicted. The example system202includes a prime mover204(e.g., a diesel engine), a transmission206, and a clutch208positioned therebetween that selectively couples the prime mover204to the transmission206. The example transmission206may be of the compound type including a main transmission section connected in series with a splitter (e.g., forward gear layers on the input shaft214) and/or range-type auxiliary section (e.g., rearward gear layers to the output shaft216). Transmissions of this type, especially as used with heavy duty vehicles, typically have 9, 10, 12, 13, 16 or 18 forward speeds. A transmission output shaft216extends outwardly from the transmission206and is drivingly connected with vehicle drive axles218, usually by means of a drive shaft220. The clutch208includes a driving portion208A connected to an engine crankshaft/flywheel222, and a driven portion208B coupled to the transmission input shaft214, and adapted to frictionally engage the driving portion208A. An electronic control unit (ECU) may be provided for receiving input signals and for processing same in accordance with predetermined logic rules to issue command output signals to the transmission system202. The system202may also include a rotational speed sensor for sensing rotational speed of the engine204and providing an output signal (ES) indicative thereof, a rotational speed sensor for sensing the rotational speed of the input shaft214and providing an output signal (IS) indicative thereof, and a rotational speed sensor for sensing the speed of the output shaft216and providing an output signal (OS) indicative thereof. The clutch208may be controlled by a clutch actuator238responding to output signals from the ECU. An example transmission206includes one or more mainshaft sections (not shown). An example mainshaft is coaxial with the input shaft214, and couples torque from the input shaft214to the output shaft216using one or more countershafts236. The countershaft(s)236are offset from the input shaft214and the mainshaft, and have gears engaged with the input shaft214and the mainshaft that are selectably locked to the countershaft236to configure the ratios in the transmission206. An example mainshaft is coupled to the output shaft216, for example utilizing a planetary gear assembly (not shown) which has selected ratios to select the range. In embodiments of the present disclosure, a motor/generator240can be selectively coupled to the driveline, for example through torque coupling to the countershaft236. Example and non-limiting torque coupling options to the driveline include a spline shaft interfacing a driveline shaft (e.g., the countershaft236), a chain assembly, an idler gear, and/or a lay shaft. As will become appreciated herein, the motor/generator240is configured to run in two opposite modes. In a first mode, the motor/generator240operates as a motor by consuming electricity to make mechanical power. In the first mode the vehicle can be moved at very low speeds (such as less than 2 MPH) from electrical power, depending upon the gear ratios between the motor/generator240and the driveline. Traditionally, it is difficult to controllably move a commercial long-haul class8vehicle at very low speeds, especially in reverse using the clutch208. In a second mode, the motor/generator240operates as a generator by consuming mechanical power to produce electricity. In one configuration a clutch242(which may be a controllable clutch and/or a one-way clutch) and a planetary gear assembly244can be coupled between the second countershaft236and the motor/generator240. The planetary gear assembly244can be a speed-up gear assembly having a sun gear304. A planetary carrier306is connected to or integral with the second countershaft236, which is connected drivably to the motor/generator240. A ring gear308(referenceFIG.3) engages planet pinions310carried by the carrier306. In an example, the planetary gear assembly244can fulfill requirements of a 21:1 cold crank ratio, for example to crank the engine204when the motor/generator240. An example motor/generator240includes motor/generator240as a 9 kW Remy 48V motor. By way of example only, the motor/generator240can be a 6-20 kW, 24-48 volt motor. The motor/generator240can be ultimately driven by the second countershaft236and be connected to an HVAC compressor246through a clutch312. The compressor246can then communicate with components of the HVAC as is known in the art. The motor/generator240can charge a battery248in an energy storage mode, and be powered by the battery248in an energy use mode. Various advantages can be realized by mounting the motor/generator240to the countershaft236of the transmission206. In one operating mode, as will be described in greater detail below, the engine can be turned off (defueled) while the vehicle is still moving or coasting and the motor/generator240is regenerating resulting in up to three percent fuel efficiency increase. In other advantages, the battery248(or batteries) can be mounted in an engine compartment near the motor/generator240reducing battery cable length over conventional mounting configurations. Moreover, various components may be eliminated with the transmission system202including, but not limited to, a starter, an alternator, and/or hydraulic power steering. In this regard, significant weight savings may be realized. In some arrangements, the transmission system202can be configured for use on vehicles with electric steering and/or other pumps or compressors. The controller224can operate the transmission system202in various operating modes. In a first mode, the controller224operates the clutch208in an open condition with the transmission206in gear. In the first mode or engine off coasting, the controller turns the engine off or defuels the engine204while the vehicle is moving based on vehicle operating conditions and routes rotational energy from the output shaft216, through the second countershaft236and into the motor/generator240. According to various examples, the vehicle operating conditions can include input signals226related to any operating conditions including but not limited to a global positioning system (GPS) signal, a grade sensor signal and/or a vehicle speed sensor signal. As can be appreciated, it would be advantageous to run the transmission system202in the first mode when the vehicle is travelling downhill. Elevation changes can be attained from a GPS signal and/or a grade sensor for example. In a second mode, the controller224operates the clutch208in a closed condition with the transmission206in neutral. In the second mode, the controller224can facilitate engine start and idle generation. In a third mode, the controller224operates the clutch208in a closed condition and the transmission206in gear. The third mode can be used for normal cruising (e.g., driving or vehicle motion) and generation. Additional operating modes provided by the transmission system202specific to engagement and disengagement with the compressor246will be described. As used herein, the modes are described as a “crank mode”, a “creep mode”, a “driving with no HVAC mode”, a “driving with HVAC mode,” and a “sleep mode”. In certain embodiments, driving modes are referenced herein as a “cruise mode” and/or as a “motive load powered mode.” These modes are described in sequence below. In an example, in the crank mode, a high ratio (e.g., 21:1) between the countershaft236and the motor/generator240is provided. Other ratios are contemplated. The HVAC compressor246would be disengaged such as by the clutch312. The transmission206would be in neutral with the clutch208closed. The motor/generator240would turn the engine204with sufficient torque to crank the engine204. In an example, in the creep mode, a high ratio (e.g., 21:1) between the countershaft236and the motor/generator240is provided. Other ratios are contemplated. The HVAC compressor246would be disengaged such as by the clutch312. The transmission206would be in first gear or low reverse gear. The clutch208would be held open with the engine204stopped (or idling). The motor/generator240would have sufficient torque to move the vehicle in forward or reverse such as at 0 MPH to 2 MPH with outstanding speed and torque control, allowing a truck to back into a trailer or a dock without damage. The utilization of the motor/generator240in the creep mode provides for a highly controllable backing torque output, and greater ease of control by the operator. In an example, in the driving with no HVAC mode, a medium ratio (e.g., 7:1) between the countershaft236and the motor/generator240is provided. Other ratios are contemplated. The HVAC compressor246would be disengaged such as by the clutch312. The transmission206would be in the appropriate gear and the clutch208would be closed while propelling the vehicle, and open with the engine off when motoring or coasting. In an example, in the driving with HVAC mode, a medium ratio (e.g., 7:1) between the countershaft236and the motor/generator240is provided. The HVAC compressor246would be engaged with a selected ratio (e.g., 3.5:1) to the motor/generator240. The transmission206would be in the appropriate gear, and the clutch208would be closed while propelling the vehicle, and open with the engine204off when motoring or coasting. The HVAC system is directly driven by the engine or the driveline, eliminating the efficiency loss of converting power to electricity and back to work. Also, the HVAC system could provide cooling in the engine off mode, converting the inertia of a vehicle on a downgrade to cooling for additional energy recovery, improving fuel savings. In the sleep mode, the motor/generator240would be disconnected from the countershaft236. The motor/generator240would be coupled to the HVAC compressor246through a selected ratio (e.g., 3.5:1). The motor/generator240uses energy previously stored in the battery248during the driving portion of the cycle to operate the HVAC. This provides the cooling function without the addition of a separate motor and power electronics to power the HVAC compressor, and/or without the addition of a separate HVAC compressor capable of being powered by an APU, electrically, or the like. A number of mechanical solutions involving sliding clutches, countershaft type gears, concentric shafts with selectable gear engagements, and planetary gears can be used to obtain the selected ratios in each operating mode. In certain embodiments, a single actuator is used to change between the above the described modes. Referring toFIG.4, a schematic block diagram of a PTO device is presented. Here, the prime mover102(e.g., engine) is drivingly coupled to the transmission104through a clutch402. The motor/generator112selectively couples to the load110and to the transmission104via a torque coupling (e.g., PTO106, which may include gear box108). The MDC114is shown as including a DC-to-DC converter404, a controller406, and an inverter408, where the converter404provides control signals to the battery assembly116, the controller408provides control signals to the PTO106, and the inverter408provides phased power to the motor/generator112. In embodiments, a PTO device coupled with a transmission104and prime mover102may support different modes of operation, such as cruise mode (e.g., accessories driven by an engine), motive load mode (e.g., accessories driven by wheels in an engine-off down-grade condition of travel), sleep mode (e.g., motor/generator operating as motor drives an HVAC with the engine off), crank mode (e.g., starting engine from the motor/generator operating as a motor, such as with a low PTO gear needed for crank-torque), creep mode (e.g., motor/generator operating as motor drives truck in low-PTO precision backing (e.g., 0-2 mph)), and the like. It will be understood that mode names are provided for clarity of description, and are not limiting to the present disclosure. Additionally or alternatively, in certain embodiments and/or in certain operating conditions, the arrangements and/or configurations of the driveline (e.g., engine, transmission, and/or wheels) may not be known to the PTO device, and/or may not be important to the PTO device. For example, in the example cruise mode and motive load mode, the driveline provides power for the shared load110, and the PTO device may be arranged to transfer power from the driveline to the load110in either of these modes. In certain embodiments, the PTO device may perform distinct operations in a mode even where the power transfer arrangements are the same, and the arrangements and/or configurations of the driveline may be known and considered by the PTO device (and/or a controller of the PTO device). For example, the PTO device may have a controller configured to determine the amount of time the vehicle operates in the cruise mode relative to the motive load mode, and accordingly the controller may make duty cycle determinations, battery charging determinations, or perform other operations in response to the time spent in each mode. ReferencingFIG.5, power flows for an example PTO device operating in a cruise mode with a prime mover102and transmission104are depicted. In the example cruise mode, the PTO device provides for efficient powering of the load110through a mechanical coupling to the drive line. In an example, a vehicle equipped with a PTO device may be able to efficiently provide power to the load110from the prime mover102, and further power the motor/generator112operating as a generator for producing electrical energy to the electrical system including for example charging a battery assembly116to store energy for future use in another operating mode. ReferencingFIG.6, power flows for an example PTO device operating in a motive load powered mode (e.g., where the motive load such as kinetic energy through the wheels is being used to power devices) is depicted. In the example motive load powered mode, the PTO device may be able to efficiently provide power to the load110from the motive load, and further power the motor/generator112operating as a generator for producing electrical energy to the electrical system including for example charging a battery assembly116to store energy for future use in another operating mode. ReferencingFIG.7, power flows for an example PTO device operating in a sleep mode (e.g., where the driveline is not capable of providing power to loads, and/or where operating conditions make driveline power undesirable) are depicted. In certain embodiments, the sleep mode may be utilized when motive loads are not available (e.g., the vehicle is not moving) and/or when the prime mover is not turning. In certain embodiments, the sleep mode may be utilized when torque engagement with the driveline is not desired—for example during shifting operations, when the prime mover is motoring but a vehicle speed is below a vehicle speed target, etc. In the example sleep mode, the PTO device is de-coupled from the driveline, and the motor/generator112powers the load110using stored energy from the electrical system, such as the battery assembly116. ReferencingFIG.8, power flows for an example PTO device operating in a crank mode (e.g., where the prime mover102is not yet started) are depicted. The example crank mode ofFIG.8depicts the motor/generator112providing power to the driveline, and the load110is de-coupled from the motor/generator112and the driveline. ReferencingFIG.9, power flows for an example PTO device operating in a creep mode (e.g., where the motor/generator112provides motive power to the driveline) are depicted. The example creep mode ofFIG.9depicts the motor/generator112providing power to the driveline, and the load110is de-coupled from the motor/generator112and the driveline. It can be seen that, in certain embodiments, the PTO device operates in the same manner in the crank mode as in the creep mode, and the system including the driveline enforces whether motor/generator112power to the driveline is applied to the motive load (e.g., the wheels) or to the prime mover102. In certain embodiments, for example where the PTO device enforces a reverse or forward position, where the PTO device uses a different gear ratio between the PTO device and the driveline in the crank mode versus the creep mode, where a controller of the PTO device notifies the system that a creep mode is being engaged, and/or where a torque response of the motor/generator112changes between the crank mode and the creep mode, the PTO device may operate in a different manner in the crank mode versus the creep mode. ReferencingFIG.10, an example perspective illustration of the mechanical layout of a PTO device is depicted. The example PTO device is configured to mount to a transmission at a PTO interface—for example to an 8-bolt PTO interface at the flange1002. The example PTO device includes a gear box108, which may be a planetary gear assembly. The example PTO device includes a torque coupling (idler gear1004in the example), a motor/generator112, and a load110. The example PTO device further includes a shift actuator1006configured to arrange the gear box108to provide the desired power flow arrangement. ReferencingFIG.11, a cutaway view of a PTO device is depicted, consistent in certain embodiments with the example depicted inFIG.10. In the example ofFIG.11, the shift actuator1006is in a “neutral” position, which prevents torque interaction between the idler gear1004and either the load110or the motor/generator112. Any arrangement of a gear box108and/or PTO device is contemplated herein. In the example ofFIG.11, the idler gear1004is driven by the driveline, and engages a driven gear1110. Further to the example ofFIG.11, ring gear1102allows the planetary gears coupled to the driven gear1110to rotate freely in the neutral position, and accordingly the load drive shaft1106does not receive or provide torque to the driveline. The motor/generator112in the example ofFIG.11is coupled to the load drive shaft1106in a ratio determined through planetary gear set1112, and accordingly the motor/generator112is capable to selectively drive the load110. In certain embodiments, the motor/generator112may be de-couplable from the load drive shaft1106, for example with a clutch (not shown). In the example ofFIG.11, sliding clutch1104is moved by the shift actuator1006to arrange the gear box108and/or planetary gear assembly. In the example ofFIG.11, stationary ring gear1114is present for engagement with the ring gar1102, although stationary ring gear1114is not engaged with the ring gear1102in the neutral position depicted inFIG.11. In certain embodiments, the example ofFIG.11is consistent with a sleep mode operation. ReferencingFIG.12, the cutaway view of the PTO device is depicted, consistent with the device ofFIG.11. In the example ofFIG.12, the shift actuator1006is in a “toward load” position, which engages ring gear1112(an inner ring gear, in the example ofFIG.12) with the driven gear1110, and the ring gear1112is driven by the driven gear1110. In the example ofFIG.12, the idler gear1004transfers torque between the driveline and the driven gear1110, and due to the coupling with the ring gear1112rotates the load drive shaft1106. In the example ofFIG.12, the motor/generator112and/or the load110are capable to be driven by the driveline, and/or may be selectably de-coupled from the load drive shaft1106(e.g., with a clutch). In certain embodiments, the example ofFIG.12is consistent with a cruise mode and/or driving mode operation. ReferencingFIG.13, the cutaway view of the PTO device is depicted, consistent with the device ofFIG.11. In the example ofFIG.13, the shift actuator1006is in a “toward motor” position, which engages ring gear1112(an outer ring gear, in the example ofFIG.13) with the stationary ring gear1114, locking the ring gear1112from rotating. In the example ofFIG.13, and the load drive shaft1106can thereby drive the driven gear1110in a reduction ratio determined by the planetary gearing coupled to the driven gear1110. In the example ofFIG.13, the motor/generator112is capable to power the driveline in a selected ratio, and in certain embodiments the load110is de-coupled form the load drive shaft1106in the position ofFIG.13. In certain embodiments, the example ofFIG.13is consistent with either a crank mode and/or a creep mode operation. ReferencingFIG.14, another cutaway view of the PTO device is depicted, consistent with the device ofFIG.11, at a different cutaway angle to depict certain aspects of the shift actuator1006(shown as cutaway shift actuator1404). The cutaway shift actuator1404drives a shift fork1402that engages the sliding clutch1104, thereby controlling the position of the PTO device gear box108. ReferencingFIG.15, a PTO device1500is shown schematically in a cutaway view. It can be seen that the ratios of the planetary gear assembly, including the planetary gear between the motor/generator112and the load drive shaft1106, the planetary gear between the load110and the load drive shaft1106, and the planetary gear associated with the driven gear1110, can be utilized to select gear ratios for various power flows through the PTO device1500. Additionally, a gear ratio between the idler gear1004and an engaged gear (e.g., one of the gears on a countershaft of the transmission), and/or a gear ratio between the idler gear1004and the driven gear1110, are design selections that affect the gear ratios of power flows through the PTO device1500. The example PTO device1500, including the utilization of one or more planetary gears in a planetary gear assembly, is a non-limiting example to illustrate a device capable to perform certain operations described throughout the present disclosure. An example PTO device can include any type of torque coupling arrangements and/or gear ratio selections (including run-time and/or design selections). One of skill in the art, having the benefit of the disclosure herein, will understand that gear ratio selections, including both actable run-time options and fixed design time selections, can be made to support a number of operating modes, loads, and the like. Certain considerations for determining gear ratio selections include, without limitation: the torque profile and operating parameters of the motor/generator; the torque requirements of the driveline including PTO torque and power limitations; the torque capabilities of the driveline including the prime mover and/or transmission; cranking torque and speed requirements of the prime mover; final gear ratios to the wheels or motive load; the torque, speed, and power requirements of the shared load; the available installation space for the PTO device; the driveline engagement options for the system (e.g., transmission PTO interfaces and available gears for coupling); the operating modes to be supported; the torque and speed maps of various devices in the system (e.g., the prime mover, the motor/generator, the transmission, and/or the vehicle system in use); the duty cycle of the vehicle and/or PTO device; offsetting costs and/or space savings from omitted devices due to the PTO device; and/or the commercial sensitivities of the system having the PTO device to capital expenditures, engineering and integration costs, and operating costs. ReferencingFIG.16, example operating speed ranges for the prime mover102are depicted. Example operating speed ranges can be determined for any aspect of the driveline and/or the system, and can be utilized to determine desired capabilities for the motor/generator112and/or for selecting gear ratios in the PTO device. In the example ofFIG.16, an operating speed1602for “start” is depicted, which may, for example, be utilized to determine gear ratios and/or motor/generator112capabilities for a crank mode operation. An operating speed1604for “idle” is depicted, which may, for example, be utilized to determine requirements to support the load110(e.g., as the load110is generally designed for proper operation at a proportion of prime mover speed, with the idle speed as the lower normal operating limit). An operating speed1606for “cruise” is depicted, which may for example be utilized to determine motor/generator112capabilities for nominal charging operations (e.g., where the motor/generator112is being charged by the driveline in cruise operations). An operating speed1608for “redline” is depicted, which may for example be utilized to determine the highest prime mover102speed expected during operation of the vehicle. The actual values for the speed ranges1602,1604,1606,1608are design considerations for a particular system, but a system can be configured with a PTO device for any speed ranges1602,1604,1606,1608. An example PTO device includes one or more aspects to protect from an overspeed operation of the motor/generator112. In an example, a 2-speed gearbox108is mounted on the PTO106with the motor/generator112and load (e.g., HVAC compressor) connected on either side. The motor/generator112is connected to the prime mover102(e.g., the engine) through a 28:1 speed ratio in the cranking mode. In an example, cranking speed of the prime mover102varies from 150 to 400 RPM, and in an example when the engine starts it speeds up (e.g., to 840 rpm). In certain embodiments, the clutch108is opened as soon as the engine starts (e.g., reaches a predetermined speed such as 400 RPM). The opening of the clutch108prevents the engine speed excursion from providing an overspeed condition to the motor/generator112. Additionally or alternatively, a clutch (not shown) between the motor/generator112and the load drive shaft1106may be utilized to prevent an overspeed condition of the motor/generator112. The example 28:1 speed ratio (motor faster) eases the torque requirement on the motor/generator112(e.g., relative to a lower ratio such as 21:1), and allows for greater off-nominal starting capability (e.g., cold start, which may have a greater torque requirement). However, a greater speed ratio may increase the likelihood that a motor/generator112overspeed may result without overspeed protection aspects. In certain embodiments, an operation to dis-engage the clutch108as soon as engine102starts is sufficiently responsive to prevent an overspeed event. For example, an engine may take 500 ms to overspeed to 840 rpm after start speed is reached, and a clutch response time can be between about 150 ms (e.g., for dis-engagement) to 250 ms (e.g., for engagement). The use of the clutch108may be desirable in certain embodiments where the designer of the PTO device also has access to controls of the clutch108and/or where appropriate communication messages to the transmission are available, and/or where the vehicle application allows utilization of the clutch108during start-up operations. In another example, engine cranking is brought close to, or into, the idle range and/or the start range, before engine fueling is enabled. For example, where the start range is considered to be 400 rpm, the motor/generator112operating in the crank mode may bring the engine speed close to (e.g., 350-400 rpm) and/or into (e.g., 400-425 rpm) the start range before engine fueling is enabled. In a further example, such as where the engine idle speed is 500 rpm, the motor/generator112operating in the crank mode may bring the engine speed close to and/or into the idle range before engine fueling is enabled. The lower speed error (e.g., close to the start and/or idle speed) and/or negative speed error (e.g., above the start and/or idle speed) introduced by the crank operations reduces (or briefly eliminates) the fueling target by the fueling governor of the engine, reducing the engine speed overshoot and accordingly the tendency for the motor/generator112to experience an overspeed event. The use of engine fueling control may be desirable in certain embodiments where the designer of the PTO device also has access to the controls of the engine102and/or where appropriate communication messages to the engine are available. In another example, the motor/generator112can be switched from the motoring mode to the generating mode as soon as the engine starts (e.g., reaches a start speed, reaches an idle speed, and/or begins fueling). Accordingly, the motor/generator112can directly dampen the engine speed excursion and reduce the tendency of the motor/generator112to overspeed. Additionally, energy harvested from the engine on startup can be stored in the battery assembly116. Any or all of the described overspeed control operations and/or aspects may be included in a particular system. ReferencingFIG.17, example operating curves for a motor/generator112are depicted. The actual values of the operating curves are design considerations for a particular system, but a system can be configured for any motor/generator112having sufficient torque (with appropriate gear ratios) and power capability (e.g., a function of the torque multiplied by the speed) to perform the desired interactions with the load and the driveline, and to support the desired operating modes of the PTO device. ReferencingFIG.18, example operating regions for the motor/generator112are depicted. In the example, region1802represents a maximum power output region (e.g., crank mode), region1804represents a high power output region (e.g., creep mode), region1806represents a nominal power output region (e.g., sleep mode, such as when the motor/generator112is powering the load110and de-coupled from the driveline), region1808represents a nominal no load region (e.g., where the motor generator112is not coupled to the driveline or powering the load110), region1810represents a normal regeneration mode (e.g., cruise mode), and region1812represents a maximum regeneration mode (e.g., regeneration from a high motive power load, such as in descending a steep hill). The actual values of the operation regions are design considerations for a particular system, but a system can be configured to support whichever operating regions are expected to be present on the vehicle. ReferencingFIG.19, an example duty cycle histogram is presented for a vehicle, with expected hours to be experienced in a max regen1902condition, a normal regen1904condition, a no load1906condition, a sleep1908condition, a creep1910condition, and a crank1912condition. The actual values of the duty cycle histogram are design considerations for a particular system, and can be used to determine, without limitation: gear ratios; which gear ratio selections should be supported; the requirements for the motor/generator112capabilities including peak and continuous ratings and high efficiency operation regions; and/or sizing of the battery assembly116. Certain further considerations for the motor/generator112and/or the battery assembly116include, without limitation: the required power levels; the driveline speeds at various operating conditions; the time and power output of the sleep mode; the availability to regenerate the battery assembly116away from the sleep mode; crank requirements (torque, time, temperature, and speed slew rate or trajectory); the efficiency profile of the motor/generator112at various speed and torque values; the cost in components, integration, and design for the provision of multiple gear ratios; and the durability and life expectations of the motor/generator112. In certain embodiments, characteristics of the motor/generator112beyond just the torque and speed considerations may be valuable for certain embodiments, and may be less desirable for other embodiments. For example, a permanent magnet motor may have higher efficiency at certain operating conditions, but may be higher cost, higher inertial torque, and lower torque capability. A permanent magnet motor may be capable of high speed operation, but may generate undesirable EMF on the motor phase lines. In another example, an externally excited motor may have lower operating efficiency, but have a low cost and the ability to selectively disable the rotor field, minimizing drag torque during no load operation. In another example, an induction motor may have a medium efficiency and high torque capability, but have higher cost, size, and weight compared to an externally excited motor. The capabilities of a particular motor further depend on the specific design, so these criteria may be different for motors of these types depending upon the specific design. Additionally or alternatively, certain aspects such as expected bearing life, brushes, control of rotating torque (e.g., a disconnecting clutch and/or capability to turn off the magnetic field), and/or maintenance requirements may make a particular motor favored or disfavored for a particular system. In certain embodiments, depending upon the desired operating modes, it may be desirable that a PTO device has an extended lifetime. For example, in certain embodiments, the PTO device, and the motor/generator112specifically, operates both during the day (e.g., regenerating the battery assembly116and/or recovering motive power) and during the night (e.g., providing climate control and powering personal devices in the sleep mode). Accordingly, the usage of the PTO device over a given period of the vehicle operating cycle may be higher than other accessories on the vehicle. Accordingly, robustness of typical failure components such as bearings may be a strong consideration for system design. Additionally, temperature control of components and/or reduced operating speeds (e.g., through gear ratio selections and/or additional gear options) for the PTO device may have particular value for certain embodiments. Incorporation of an PTO device having a motor/generator112system into a traditional production electrical system may include changes to the electrical system, such as conversion of power distribution from a 12V system to a 12V/48V system, removal of the starter and alternator, restructuring the startup sequence, control of accessory and ignition modes, and the like. In embodiments, a networked communication system (e.g., Controller Area Network (CAN)) may provide for communications amongst PTO electrical components, such as with the ECU122, TCU120, and the like. For the startup sequence of a prime mover102having a PTO device integrated therewith, the starter and/or the alternator may be removed and replaced by the PTO device components (e.g., load110, gearbox108, motor/generator112, and the like). In the traditional production system, starting is controlled through a network of relays, which could be cumbersome to control all of the available operating modes for the PTO device, so the PTO device sequence, operating states, and other state control functions may be managed through a networked communication system. For example, a general engine start sequence may be as follows: (1) a driver turns the key to an ignition position, (2) ECU122, TCU120, and MDC114are turned on, (3) the driver turns the key to a start position, (4) control units check for the system being ready to start (e.g., the TCU120checks that transmission is in neutral and broadcasts over network, ECU122checks that the engine is ready to start and broadcasts over the network, and the like), (5) engine is started (e.g., MDC114cranks engine, ECU120starts fueling and controlling the engine, and the like), and (6) the driver returns the key to the ignition position. The PTO device may include a shift control override, such as where the transmission cannot be shifted with PTO load on the countershaft. For example, before each shift, the TCU120commands the MDC114to bring the motor shaft to zero torque. The PTO device may include a sleep mode and wake mode, such as where the load110(e.g., HVAC compressor) can be enabled with the engine off. In embodiments, the motor drive converter (MDC)114may be a combined motor drive and DC-DC converter intended to support electrification of vehicles, such as using a multi-rail 48 V/12 V architecture. The motor drive supports starter and generator operation of a motor/generator112(e.g., a permanent magnet synchronous motor, wire-wound synchronous motor, induction motor, and the like) and the DC-DC converter bridges system voltages (e.g., a 48V system and a 12V system with bidirectional power flow). Motor position information is provided from a sensor in the motor/generator112, such as fed to a field-oriented control algorithm running on a processor in the MDC114. The MDC114may provide for continuous and peak power (e.g., 10 kW peak/5 kW continuous power), such as providing transient 10 kW power (e.g., 30 seconds) during crank mode, continuous 5 kW power during cruise mode in flat road conditions (e.g., split between the 48V sub-system and the DC-to-DC converter sub-system), continuous 3 kW continuous power during sleep mode, and the like. The MDC enclosure may be configured to efficiently dissipate heat, such as being made of an aluminum heatsink. The assembled MDC114, when mated with electrical connectors, may provide ingress protection for the internal components, as well as oleophobic and hydrophobic protection, such as with a vent to reduce structural loads on the enclosure when exposed to altitude and temperature gradients. ReferencingFIG.20, an example physical layout of an MDC114is depicted, showing DC power input signals from the battery assembly116(e.g., DC Ground2002, 12V DC2004, 48V DC2006), AC power phased output signals to the motor/generator112(e.g., 48-VAC 3-phases2008A,2008B,2008C), communications signals (e.g., motor communications2010, PTO communications2012, truck communications2014, and the like). The location of the MDC114may be near to both the transmission104and battery assembly116to minimize heavy cabling and voltage drop in the system. For example, the MDC114may be located on a surface of battery box of the battery assembly116. In certain embodiments, the MDC114may be distributed and have certain aspects located throughout the system. ReferencingFIG.21A, an example power distribution configuration for a PTO device is depicted. Power distribution may be configured to run off one or more configurations of the battery assembly116, such as banks of 12V batteries, separate 12V and 48V batteries, and the like. For example, as depicted inFIG.21A, the battery assembly116may be configured of a battery pack of four 12V batteries in series, providing a 48V power interface2118. In the example ofFIG.21A, the battery assembly116further includes a quarter-tapped 12V power interface2120, providing for the 12V power. The example ofFIG.21Afurther includes communications2110to the MDC114such as a motor speed (e.g., provided by the motor and/or a speed sensor), communications2112with a system (e.g., providing auxiliary I/O, temperatures, etc.), and/or communications2114with a vehicle (e.g., providing vehicle state information, keyswitch signal, CAN communications, or the like). The example ofFIG.21Afurther includes a chassis electrical coupling2116(e.g., for grounding), and communications2108between the MDC114and the motor112(e.g., three-phase AC power from controlled inverters on the MDC114). ReferencingFIG.21B, a PTO device further includes the battery assembly116having a single 48V battery2104(e.g., a Li-ion battery), with a separate 12V battery to provide the 12V power interface2120. ReferencingFIG.22, an example battery assembly116further includes a two battery packs2202,2204each having 4 four 12V batteries in series (8 total batteries in the example ofFIG.22). In the example ofFIG.22, the 12V power interface2120may include a single 12V battery providing the 12V power, or a pair of 12V batteries in parallel (e.g., one from each of the battery packs), depending upon the amount of 12V energy storage is desired for the system. The selection of the number of batteries to include in a battery assembly116is a design choice that depends upon the system voltages desired (e.g., both the number of distinct voltages, and the values of those voltages), the total amount of energy that is to be stored in the battery pack, the amount of current to be delivered by the battery pack, and the voltages, energy capacities, and current capacities of the batteries in the battery pack. As depicted inFIG.22, a first bank of 12V batteries2202and second bank of 12V batteries2204may be utilized. The 12V and 48V outputs may be connected through the MDC's DC-to-DC converter and monitored by the battery management system (BMS)118. The BMS118may monitor and report back current, voltage, and temperature measurements and, when the DC-to-DC converter is off, may have the ability to send a wake signal to enable charging and balancing. The BMS118may monitor battery conditions for life-time characteristics, such as voltages for different batteries throughout the charge-discharge, and provide active balancing via discharge control to manage the batteries to the same voltage. The PTO device electrical system may implement a single point ground2116, such as with a central ground located on the negative terminal of the MDC114, with battery strings grounded to that point. As depicted inFIGS.21A,21B, and22, the MDC114provides the three-phase power lines2108to the motor/generator112, such as input voltages when the motor/generator112is operating as a motor and output voltages when the motor/generator112is operating as a generator. Control and sensor signals may also be provided to/from the MDC114in the control of the PTO system, such as position information2110from the motor/generator112, auxiliary I/O and temperature data2112for the system, key switch information and network data2114for the vehicle, and the like. FIG.23depicts a 48-volt system architecture for an electrically regenerative accessory drive in an embodiment of the present disclosure. In addition to other examples depicted throughout the present disclosure, the example ofFIG.23depicts a number of communication networks distributed around the vehicle. For example, communication link2302is depicted with the ECU122in communication with the TCU120, for example on a private CAN link, or on a J1939 public datalink, and/or a network having any known communication protocol. Communication link2304similarly is depicted between the TCU120and the MDC114, which may be the same communication link as link2302, or a separate link, and may be private or public. Additionally or alternatively, any one or more of the datalinks may be a wireless datalink. The example ofFIG.23utilizes two battery packs, each having 4 batteries in series. FIG.24depicts a state diagram for an example motor/generator112. The example state diagram includes a keyoff state2402, for example a starting condition for the motor/generator112applied by the MDU112at a startup time for the vehicle. The example state diagram depicts a transition to an engine off state2404, for example in response to a keyswitch signal before the engine is started. The example state diagram further depicts a transition to a sleep state2406, for example in response to a system shutdown and/or an auxiliary input (e.g., from a sleeper cab console or a selected keyswitch position) to the MDU114indicating that powering of a shared load110is desired even though the engine is not running. The example state diagram further includes a transition back to the engine off state2404when conditions are met (e.g., an auxiliary input is no longer present). The example state diagram further includes a transition to crank state2408(to start the engine), and/or a neutral state2410(e.g., the PTO device is not in torque communication with the driveline). The driving state2412(or cruise, etc.) can be transitioned to when the vehicle is moving, and the states2414(driving in coast) and2416(driving with engine off—e.g., motoring) are available under the appropriate system conditions. The crank state2418is depicted from the engine stop state2420(e.g., for a start/stop embodiment of the PTO device), but the crank state2408may additionally or alternatively be utilized. The creep engine on state2436and creep engine off states2424are depicted, depending upon the conditions present in the system, and the desired configuration to engage a creep mode. Finally, the drive shifting state2422is depicted, which may be utilized, for example, to provide for the PTO device to decouple from the driveline (e.g., engage a neutral position of the shift actuator1006) during a shifting event. The depicted states are non-limiting, and the state diagram provides an example framework to control the transitions of the PTO device between operating modes. ReferencingFIG.25, an example depiction of power flows through the PTO device in a sleep mode is depicted. The example PTO device includes the motor/generator112powering the load110through the load drive shaft, for example with a first gear ratio applied at the planetary gear coupling the motor/generator112to the load drive shaft, and with a second gear ratio applied at the planetary gear coupling the load110to the load drive shaft. The PTO device in the position depicted inFIG.25does not communicate torque with the driveline. For clarity of presentation, the countershaft2502from an example transmission and the clutch2504between the transmission and the prime mover is depicted, but power does not flow from the driveline to the PTO device in the example ofFIG.25. In certain embodiments, an actuator1104in the neutral position provides the PTO device configured as inFIG.25. ReferencingFIG.26, an example depiction of power flows through the PTO device in a cruise mode and/or motive load powered mode is depicted. The example PTO device includes the drive shaft powering the motor/generator112and the load110through the load drive shaft, for example with selected gear ratios provided between the countershaft and the idler gear, between the idler gear and the driven gear, and between the driven gear and the load drive shaft. Further, the planetary gears at the motor/generator112and the load110, respectively, provide further selectable gear ratios. In certain embodiments, an actuator in the “toward load” position provides the PTO device configured as inFIG.26. ReferencingFIG.27, an example depiction of power flows through the PTO device in a crank mode and/or a creep mode is depicted. The example PTO device includes the motor/generator112powering the drive shaft, for example with selected gear ratios provided between the countershaft and the idler gear, between the idler gear and the driven gear, and between the driven gear and the load drive shaft. In the example ofFIG.27, the planetary gear associated with the driven gear provides for an additional ratio between the motor/generator112and the driveline, allowing for an increase in torque by the motor/generator112to the driveline. In certain embodiments, the load110may be powered during crank mode and/or creep mode operations, and/or the load110may be de-coupled from the load drive shaft (e.g., using a clutch). Further, the planetary gears at the motor/generator112and the load110, respectively, provide further selectable gear ratios. In certain embodiments, an actuator in the “toward motor” position provides the PTO device configured as inFIG.27. An example system includes a PTO device that selectively couples to a driveline of a vehicle, a motor/generator112electrically coupled to an electrical power storage system, a shared load110selectively powered by the driveline or the motor/generator112. The example system further includes where the PTO device further includes a coupling actuator (e.g., shift actuator1006, gear box108, idler gear1004, and/or planetary gear assembly) that couples the shared load110to the motor/generator112in a first position, and to the driveline in a second position. An example system includes where the coupling actuator further couples the driveline to the motor/generator in the second position, where the coupling actuator includes a two-speed gear box, and/or where the coupling actuator couples the motor-generator to the shared load in a first gear ratio in the first position (e.g., neutral or sleep mode), and couples the motor-generator to the driveline in a second gear ratio in the second position (e.g., cruise mode). An example system includes where the coupling actuator couples the motor/generator to the driveline in a second gear ratio in the second position (e.g., cruise mode), and in a third gear ratio in a third position (e.g., crank or creep mode); where the coupling actuator further couples the motor/generator to the driveline in the second gear ratio in response to the driveline providing torque to the motor/generator; and/or where the coupling actuator further couples the motor/generator to the driveline in the third gear ratio in response to the motor/generator providing torque to the driveline. An example system includes where the coupling actuator further de-couples the motor/generator from the driveline in the first position. ReferencingFIG.28, an example procedure includes an operation3102to selectively power a shared load with a motor/generator in a first operating mode (e.g., neutral or sleep mode), and with a driveline in a second operating mode (e.g., cruise mode); an operation3104to provide a first gear ratio between the motor/generator and the shared load in the first operating mode; and an operation3106to provide a second gear ratio between the driveline and the motor/generator in the second operating mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to power the motor/generator with the driveline in the second operating mode, and an operation to charge an electrical power storage system with the motor/generator in the second operating mode; an operation to power the motor/generator with the electrical power storage system in the first operating mode; an operation to power the driveline with the motor/generator in a third operating mode; and/or an operation to provide a third gear ratio between the motor/generator and the driveline in the third operating mode. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle, a motor/generator112electrically coupled to an electrical power storage system (e.g., battery assembly116), a shared load110selectively powered by one of the driveline or the motor/generator, and where the PTO device further includes a coupling actuator including a planetary gear assembly, the coupling actuator structured to couple the shared load to the motor/generator at a first gear ratio in a first position (e.g., neutral or sleep mode) of the planetary gear assembly, and to couple the shared load to the driveline at a second gear ratio in a second position (e.g., cruise mode) of the planetary gear assembly. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the first position of the planetary gear assembly includes a neutral position that de-couples the driveline from both of the motor/generator and the shared load. An example system includes where the shared load is selectively rotationally coupled to a load drive shaft1106, and where the motor/generator is selectively rotationally coupled to the load drive shaft through a second planetary reduction gear, and/or where the shared load is selectively rotationally coupled to the load drive shaft through at least one of a clutch and a third planetary gear. An example system includes where the coupling actuator is further structured to couple the driveline to the motor/generator at a third gear ratio in a third position (e.g., crank or creep mode) of the planetary gear assembly, where the second position of the planetary gear assembly includes a ring gear of the planetary gear assembly engaging a driven gear of the planetary gear assembly, where the first position of the planetary gear assembly includes a free-wheeling position of the planetary gear assembly, where the third position of the planetary gear assembly includes engaging a second ring gear of the planetary gear assembly with a stationary gear of the planetary gear assembly, and/or where the ring gear includes an inner ring gear, and where the second ring gear includes an outer ring gear. ReferencingFIG.29, an example procedure includes an operation3202to selectively power a shared load between a driveline of a vehicle and a motor/generator, an operation3204to selectively power including positioning a planetary gear assembly into a first position de-coupling the driveline from the shared load, thereby powering the shared load with the motor/generator; and an operation3206to position the planetary gear assembly into a second position coupling the driveline to the shared load, thereby powering the shared load with the driveline. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to power the motor/generator with the driveline in the second position of the planetary gear assembly, thereby charging an electrical power storage system with the motor/generator; an operation to selectively power the driveline with the motor/generator; where an operation to selectively power the driveline includes positioning the planetary gear assembly into one of the second position or a third position, thereby coupling the driveline to the motor/generator, and where a gear ratio between the driveline and the motor/generator in the second position is distinct from a gear ratio between the driveline and the motor/generator in the third position; and/or an operation to de-couple the shared load from the motor/generator during the powering the driveline with the motor/generator. An example system includes a PTO device structured to selectively couple to a transmission of a vehicle; a motor/generator112electrically coupled to an electrical power storage system116; a shared load110selectively powered by one of a driveline of the vehicle or the motor/generator, where the PTO device further includes a coupling actuator structured to couple the driveline to the motor/generator in a first position (e.g., neutral or sleep mode), and to the shared load in a second position (e.g., cruise mode); and where the PTO device includes a housing having a first interface (e.g.,FIG.10—gear box108interface to the motor/generator112) coupled to the motor/generator and a second interface (e.g.,FIG.10—gear box108interface to the load110) coupled to the shared load, and where the first interface is displaced at least 90 degrees from the second interface. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the first interface is in an opposite direction from the second interface. An example system includes a load drive shaft1106disposed in the PTO device, where a first end of the load drive shaft is positioned toward the first interface and where a second end of the load drive shaft is positioned toward the second interface. An example system includes a first one of the first interface or the second interface is positioned toward a front of the vehicle, and where the other one of the first interface or second interface is positioned toward a rear of the vehicle. An example system includes the housing further including a third interface (e.g.,FIG.10, flange1002) coupled to the transmission, and where the third interface includes an orientation perpendicular to the load drive shaft. An example system includes the housing further including a T-shape. An example system includes the housing further including a third interface coupled to a side PTO interface of the transmission, and/or where the side PTO interface includes an 8-bolt PTO interface. An example system includes the housing further including a third interface coupled to the transmission, and where the PTO device further includes a driveline coupling device structured to selectively access power from the driveline; the driveline coupling device including an idler gear1104engaging a countershaft gear of the transmission; the driveline coupling device including a chain (not shown—e.g., side engagement to a countershaft, chain coupling a layshaft to a countershaft gear, etc.) engaging a countershaft gear of the transmission; the driveline coupling device including a splined shaft engaging a countershaft of the transmission (e.g., a rear PTO interface); the driveline coupling device including a layshaft engaging a gear of the transmission (e.g., layshaft to extend mechanical reach, and/or apply a further selected gear ratio); and/or the driveline coupling device including a chain engaging a gear of the transmission (e.g., any gear which may or may not be a countershaft gear). ReferencingFIG.30, an example system includes a PTO device3302having a coupling actuator (e.g., shift actuator1006, gear box108, idle gear1004, and/or planetary gear assembly) configured to couple a shared load110to a motor/generator112in a first position (e.g., neutral or a sleep mode), and to couple the shared load to a driveline of a vehicle in a second position (e.g., a cruise mode); a controller3304including a driving mode circuit3306structured to determine a current vehicle operating mode (e.g., utilizing keyswitch, network signals, operations exercising a state diagram, vehicle conditions such as vehicle speed, power or torque output, etc.) as one of a sleep mode or a motive mode (e.g., cruise, driving, etc.); and a shared load operating mode circuit3308structured to command the coupling actuator to the first position in response to the sleep mode, and to command the coupling actuator to the second position in response to the motive mode. An example system includes the coupling actuator further configured to de-couple the driveline from the shared load and the motor/generator in the first position. An example system includes where the coupling actuator is further configured to couple the driveline of the vehicle to the motor/generator in a third position and/or where the driving mode circuit3306is further structured to determine the current vehicle operating mode as a creep mode, and where the shared load operating mode circuit3308is further structured to command the coupling actuator to the third position in response to the creep mode. An example system includes a load drive shaft1106selectively coupled to the shared load, where the motor/generator powers the load drive shaft in the first position, and where the driveline powers the load drive shaft in the second position; a shared load coupling actuator structured to selectively de-couple the shared load from the load drive shaft; and where the shared load operating mode circuit3308is further structured to command the shared load coupling actuator to de-couple the shared load from the load drive shaft in response to the creep mode. An example system includes where the driving mode circuit3306is further structured to determine the current vehicle operating mode as a crank mode, and where the shared load operating mode circuit3308is further structured to command the coupling actuator to the third position in response to the crank mode. An example system including where the coupling actuator is further configured to selectively couple the motor/generator to the driveline of the vehicle in the second position; an electrical stored power circuit3310structured to determine a state of charge of an electrical power storage system (e.g., battery assembly116), and where the shared load operating mode circuit3308is further structured to command the coupling actuator to couple the motor/generator to the driveline of the vehicle in the second position in response to the state of charge of the electrical power storage system; and/or the coupling actuator is further configured to couple the driveline of the vehicle to the motor/generator in a third position, and where a first gear ratio between the motor/generator and the driveline of the vehicle in the second position is distinct from a second gear ratio between the motor/generator and the driveline of the vehicle in the third position (e.g., gear ratio between motor/generator and driveline is different between cruise mode and creep mode). ReferencingFIG.31, an example procedure includes an operation3402to determine a current vehicle operating mode as one of a sleep mode or a motive mode; an operation3404to command a coupling actuator to couple a shared load to a driveline of a vehicle in response to the motive mode; and an operation3406to command the coupling actuator to couple the shared load to a motor/generator in response to the sleep mode. An example procedure further includes an operation to de-couple the driveline of the vehicle from both of the shared load and the motor/generator in response to the sleep mode. An example procedure further includes an operation to determine the current vehicle operating mode as a creep mode, and to command the coupling actuator to couple the motor/generator to the driveline in response to the creep mode. An example procedure further includes an operation to determine the current vehicle operating mode as a crank mode, and to command the coupling actuator to couple the motor/generator to the driveline in response to the crank mode. An example procedure further includes an operation to selectively couple the driveline to the motor/generator in response to the motive mode (e.g., cruise mode, driving mode, etc.); an operation to determine a state of charge of an electrical power storage system, and where the selectively coupling the driveline to the motor/generator is further in response to the state of charge. Example and non-limiting operations to selectively couple the driveline to the motor/generator in response to the state of charge include one or more of the following operations: determining that a state of charge of the electrical power storage system (e.g., battery assembly) is below a threshold; determining that a state of charge of the battery assembly is sufficiently low that an estimated amount of regeneration activity of the vehicle can be stored; determining that a state of charge of the battery assembly is below an amount estimated to provide sufficient upcoming sleep mode operation for a predetermined amount of time; and/or determining that a battery assembly charge level should be increased to protect the battery assembly state of health. An example procedure further includes an operation to determine the current vehicle operating mode as one of a crank mode or a creep mode, an operation to command the coupling actuator to couple the motor/generator to the driveline in response to the one of the crank mode or the creep mode; and/or an operation to command the coupling actuator to couple the motor/generator to the driveline at a first gear ratio in response to the motive mode, and to couple the motor/generator to the driveline at a second gear ratio in response to the one of the crank mode or the creep mode, and where the first gear ratio is distinct from the second gear ratio. Again referencingFIG.30, an example system includes a PTO device having a coupling actuator configured to couple a shared load to a motor/generator in a first position, to couple the shared load to a driveline of a vehicle in a second position, and to couple the motor/generator to the driveline of the vehicle in a third position. The system further includes a controller3304including a driving mode circuit3306structured to determine a current vehicle operating mode as one of a sleep mode, a motive mode, or a creep mode, and a shared load operating mode circuit3308structured to command the coupling actuator to the first position in response to the sleep mode, to command the coupling actuator to the second position in response to the motive mode, and to command the coupling actuator to the third position in response to the creep mode. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the controller3304further includes a reverse enforcement circuit3312structured to determine a reverse gearing position. Operations to determine a reverse gearing position include providing and/or receiving messages on a datalink to confirm gear configurations, receiving a transmission state value indicating whether a reverse gearing position is present, and/or receiving a creep permission value indicating that creep operations that may cause vehicle movement are permitted. In certain embodiments throughout the present disclosure, datalink communications and/or other messages may be received by receiving a dedicated datalink message, by receiving an agreed upon message that is not dedicated but that provides an indication of the received information, determining the information for a message from other information available in the system (e.g., a positive forward vehicle speed could be utilized to preclude a reverse creep operation), communicating with a sensor detecting the value (e.g., a transmission gear position sensor), and/or by receiving an indicator (e.g., a voltage detected at a location, such as a controller I/O location, a hardwired input to the MDC114, or other indicator) of the requested value. An example shared load operating mode circuit3308is further structured to command the coupling actuator to the third position in response to the reverse gearing position. An example system includes where the shared load operating mode circuit3308is further structured to provide a motor/generator direction command value in response to the creep mode, and where the motor/generator is responsive to the motor/generator direction command value. For example, in certain systems, a creep mode may allow the PTO device to provide either forward or reverse motive power the vehicle, and the direction selection may be performed by a gear selection (e.g., requesting a reverse gear shift by the transmission) and/or by controlling the rotating direction of the motor/generator. In certain embodiments, creep operations may be combined with other protective operations, such as decoupling the prime mover from the driveline (e.g., opening the clutch108) to prevent reverse rotation of the prime mover. Additionally or alternatively, a reversing gear can be provided in the gear box108, for example for coupling the PTO device to the driveline for the creep mode (and/or for the crank mode, such as where the normal coupling results in a reverse gear). An example system includes the driving mode circuit3306further structured to determine the current vehicle operating mode as a crank mode, and where the shared load operating mode circuit3308is further structured to command the coupling actuator to the third position in response to the crank mode; where the shared load operating mode circuit3308is further structured to provide the motor/generator direction command value further in response to the crank mode; and/or where the shared load operating mode circuit3308is further structured to provide the motor/generator direction command value as a first direction in response to the crank mode, and as a second direction in response to the creep mode. An example system includes where a first rotational coupling direction between the motor/generator and the driveline in the second position is opposite a second rotational coupling direction between the motor/generator and the driveline in the third position. ReferencingFIG.32, an example procedure includes an operation3602to determine a current vehicle operating mode as one of a sleep mode, a motive mode, or a creep mode; an operation3604to command a coupling actuator to a first position coupling a shared load with a motor/generator in response to the sleep mode; an operation3606to command the coupling actuator to a second position coupling the shared load with a driveline of a vehicle in response to the motive mode; and an operation3608to command the coupling actuator to a third position coupling the motor/generator with the driveline of the vehicle in response to the creep mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to determine a reverse gearing position, and to command the coupling actuator to the third position further in response to the reverse gearing position; an operation to determine the reverse gearing position in response to a transmission state value; an operation to determine the reverse gearing position in response to a creep permission value; an operation to provide a motor/generator direction command value in response to the creep mode; an operation to determine the current vehicle operating mode as a crank mode, and commanding the coupling actuator to the third position in response to the crank mode; and/or an operation to provide the motor/generator direction command value as a first direction in response to the creep mode, and as a second direction in response to the crank mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to determine a reverse gearing position; an operation to command the coupling actuator to the third position in response to a predetermined correlation between: one of the crank mode or the creep mode; and the reverse gearing position. An example system includes a countershaft transmission, having an input shaft coupled to a prime mover, an output shaft coupled to a motive driveline, and a countershaft selectively transferring torque from the input shaft to the output shaft at selected gear ratios. The transmission further includes a PTO gear including a transmission housing access at a selected gear on the countershaft (e.g., a side access providing a coupling access to a selected gear on the countershaft). The example system further includes a PTO device structured to selectively couple to the selected gear on the countershaft; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the selected gear or the motor/generator; and where the PTO device further includes a sliding clutch structured to couple the shared load to the motor/generator in a first position, and to the selected gear in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a main shaft of the transmission coupled to the output shaft of the transmission (e.g., through a planetary gear assembly), and where the countershaft transfers torque to the output shaft through the main shaft (e.g., the countershaft receives torque through a first gear mesh from the input shaft, and transfers torque through a second gear mesh to the main shaft, thereby transferring torque to the output shaft). An example system includes where the selected gear on the countershaft corresponds to a direct drive gear of the input shaft (e.g., a gear at a lockup position between the input shaft and the main shaft). An example system includes where the transmission housing access includes an 8-bolt PTO interface. An example system includes where the PTO device further includes an idler gear engaging the selected gear. An example system includes a countershaft transmission, having an input shaft coupled to a prime mover; an output shaft coupled to a motive driveline; and a countershaft selectively transferring torque from the input shaft to the output shaft at selected gear ratios; a PTO access including a rear transmission housing access positioned at the countershaft; a PTO device structured to selectively couple to the countershaft; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the selected gear or the motor/generator; and where the PTO device further includes planetary gear assembly structured to couple the shared load to the motor/generator in a first position, and to the countershaft in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the PTO device further includes a splined shaft engaging the countershaft. An example system includes a clutch interposed between the motor/generator and the planetary gear assembly, where the clutch is structured to selectively disconnect the planetary gear assembly from the countershaft. An example system includes where the planetary gear assembly is further structured to further couple the motor/generator to the countershaft in the second position, and/or where the planetary gear assembly is further structured to couple the motor/generator to the countershaft in a third position, to provide a first gear ratio between the motor/generator and the countershaft in the second position, and to provide a second gear ratio between the motor/generator and the countershaft in the third position. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator at a first selected ratio in a first position (e.g., a neutral or sleep mode), and to couple the shared load to the driveline at a second selected ratio in a second position (e.g., a cruise mode or driving mode). Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the coupling actuator is further structured to couple the motor/generator to the driveline at a third selected ratio in the second position. An example system includes where the coupling actuator is further structured to couple the motor/generator to the driveline at a fourth selected ratio in a third position (e.g., a creep mode or a cranking mode); a load drive shaft selectively coupled to the shared load, where the motor/generator powers the load drive shaft in the first position, and where the driveline powers the load drive shaft in the second position; where the coupling actuator is further structured to de-couple the shared load from the load drive shaft in the third position; and/or where the coupling actuator is further structured to de-couple the load drive shaft from the driveline in the first position. An example system includes where the motor/generator is further structured to charge the electrical power storage system in the second position. ReferencingFIG.33, an example procedure includes an operation3702to selectively power a shared load with a motor/generator in a first operating mode and with a driveline of a vehicle in a second operating mode, where the selectively powering includes an operation3704to couple the driveline to the shared load at a first selected ratio and to the motor/generator at a second selected ratio in the first operating mode; and an operation3706to couple the motor/generator to the shared load at a third selected ratio in the second operating mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to selectively power the driveline with the motor/generator in a third operating mode at a fourth selected ratio; where the third operating mode includes a creep mode, and an operation to power the driveline with the motor/generator provides motive power to the driveline; an operation to selectively power the driveline with the motor/generator in a fourth operating mode at a fifth selected ratio; and/or where the fourth operating mode includes a crank mode (e.g., providing distinct ratios between the motor/generator and the driveline between the crank mode and the creep mode), and where an operation to power the driveline with the motor/generator provides cranking power to start a prime mover coupled to the driveline. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a power flow control device (e.g., including at least one or more of an MDC114, shift actuator1006, gear box108, planetary gear assembly, idler gear1004, torque coupling, one or more clutches, and/or a coupling actuator) structured to power a shared load with a selected one of the driveline or the motor/generator; where the power flow control device is further structured to selectively transfer power between the motor/generator and the driveline; and where the power flow control device is further structured to de-couple both of the motor/generator and the shared load from the driveline when the motor/generator powers the shared load. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the power flow control device is further structured to power the motor/generator with the driveline to charge the electrical power storage system. An example system includes where the electrical power storage system is sized to provide a selected amount of off-line power for a selected amount of time; where the selected amount of off-line power includes at least one of the amounts consisting of: an amount of power drawn by the shared load, an amount of power to operate a climate control system of the vehicle, an amount of power to operate a climate control system of the vehicle plus vehicle living space accessories, and/or an amount of power to operate accessories of a vehicle; and/or where the selected amount of time includes at least one of the amounts of time consisting of: 30 minutes, 2 hours, 8 hours, 10 hours, 12 hours, and 24 hours. An example system includes power electronics (e.g., an inverter, a rectifier, and/or a DC/DC converter) disposed between the electrical power storage system and at least one accessory of the vehicle, where the power electronics are structured to configure electrical power provided from the electrical power storage to an electrical power format (e.g., a voltage level, an RMS voltage, a frequency, a phase, and/or a current value) for the at least one accessory; and/or where each of the at least one accessories comprise one of a nominal 12V DC (e.g., 11.5-12.5V, 10.5-14V, 9V-15V, etc.) accessory and a nominal 110V AC (e.g., 110V, 115V, 120V, 50 Hz, 60 Hz, etc.) accessory. An example system includes where the power flow control device is further structured to de-couple the motor/generator from the shared load when the motor/generator powers the driveline; and/or where the power flow control device is further structured to provide a first gear ratio between the motor/generator and the driveline when powering the motor/generator from the driveline, and to provide a second gear ratio between the motor/generator and the driveline when powering the driveline with the motor/generator. An example system includes where the power flow control device including a planetary gear assembly structured to route power between the shared load, the motor/generator, and the driveline; where the planetary gear assembly further includes a driven gear coupled to a countershaft gear; and/or where the power flow control device further includes an idler gear interposed between the driven gear and the countershaft gear. ReferencingFIG.34, an example procedure includes an operation3802to selectively power a shared load with one of a motor/generator or a driveline of a vehicle; an operation3804to selectively couple the motor/generator to the driveline to provide a selected one of powering the driveline with the motor/generator or powering the motor/generator with the driveline; and an operation3806to de-couple the motor/generator from the driveline in response to powering the shared load with the motor/generator. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to couple the motor/generator to the driveline to charge an electrical power storage system; and operation to power an off-line device with at least one of the motor/generator or the electrical power storage system in response to a prime mover of the vehicle being shut down (e.g., keyswitch is off, motive power request is zero, keyswitch is in an auxiliary position, a state value indicates the prime mover is shutting down, and/or a speed value of the prime mover indicates shutdown, etc.); an operation to configure electrical power from the electrical power storage system to an electrical power format for the off-line device; where the shared load includes a climate control device for the vehicle, and an operation to selectively power the shared load with the motor/generator is in response to the prime mover of the vehicle being shut down. ReferencingFIG.35, an example system includes a PTO device3902structured to selectively couple to a driveline of a vehicle; a motor/generator3904electrically coupled to an electrical power storage system; a controller3906, including: a driving mode circuit3908structured to determine a current vehicle operating mode as one of a motive power mode or a charging mode; a PTO coupling circuit3910structured to provide a motive power coupling command in response to the motive power mode, and to provide a charge coupling command in response to the charging mode; and where the PTO device includes a coupling actuator responsive to the motive power coupling command to couple the motor/generator to the driveline of the vehicle in a first gear ratio, and responsive to the charge coupling command to couple the motor/generator to the driveline of the vehicle in a second gear ratio. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the motive power mode includes one of a crank mode, a creep mode, or a launch mode. An example system includes where the driving mode circuit3908is further structured to determine the charging mode in response to a state of charge of the electrical power storage system. An example system includes an accessory, and where the coupling actuator selectively couples the accessory to one of the driveline or the motor/generator; and/or where the driving mode circuit3908is further structured to determine the current vehicle operating mode as a sleep mode, where the PTO coupling circuit3910is further structured to provide a sleep power command in response to the sleep mode, and where the coupling actuator is further responsive to couple the motor/generator to the accessory in response to the sleep power command. An example system includes a motor/generator operating profile circuit3912structured to determine a motor/generator efficient operating point, and where the PTO coupling circuit3910is further structured to adjust the charge coupling command in response to the motor/generator efficient operating point, and where the coupling actuator is further responsive to the adjusted charge coupling command to couple the motor/generator to the driveline of the vehicle in a selected one of the first gear ratio and the second gear ratio. ReferencingFIG.36, an example procedure includes an operation4002to determine a current vehicle operating mode as one of a motive power mode or a charging mode; an operation4004to couple a motor/generator to a driveline of a vehicle in a first gear ratio in response to the motive power mode; and an operation4006to couple the motor/generator to the driveline of the vehicle in a second gear ratio in response to the charging mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to determine a state of charge of an electrical power storage system electrically coupled to the motor/generator, and determining the vehicle operating mode as the charging mode further in response to the state of charge of the electrical power storage system; an operation to power an accessory from a selected one of the driveline and the motor/generator; an operation to determine the vehicle operating mode as a sleep mode, and selecting the motor/generator to power the accessory in response to the sleep mode; an operation to select the one of the driveline and the motor/generator in response to the state of charge of the electrical power storage system; and/or an operation to determine a motor/generator efficient operating point (e.g., a speed and/or torque output of the motor/generator that is in a high efficiency operating region, and/or that is in an improved efficiency operating region; where the operation to determine the motor/generator efficient operating point may further include searching the space of available operating points based on available gear ratio selections), and coupling the motor/generator to the driveline of the vehicle in a selected one of the first gear ratio and the second gear ratio further in response to the motor/generator efficient operating point. ReferencingFIG.37, an example system includes a PTO device4104structured to selectively couple to a driveline of a vehicle; a motor/generator4106electrically coupled to an electrical power storage system; a shared load4102selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple: the shared load to the motor/generator in a first position; the shared load and the motor/generator to the driveline in a second position; and the shared load to the driveline in a third position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the coupling actuator includes a planetary gear assembly having a planetary gear with three positions, where a first position of the planetary gear couples the motor/generator to the driveline in a first gear ratio, where a second position of the planetary gear couples the motor/generator to the driveline in a second gear ratio, and where a third position de-couples the motor/generator from the driveline; a load drive shaft, where the coupling actuator further includes at least one of a clutch and a second planetary gear, and where the at least one of the clutch and the second planetary gear couple the shared load to the load drive shaft in a first position, and de-couple the shared load from the load drive shaft in a second position; and/or a third planetary gear coupling the motor/generator to the load drive shaft. An example system includes a controller4108, the controller including a system efficiency description circuit4110structured to determine at least one efficiency value selected from the efficiency values consisting of: a driveline efficiency value, a motor/generator efficiency powering value, and a motor/generator efficiency charging value; and a shared load operating circuit4112structured to command the coupling actuator in response to the at least one efficiency value; and where the coupling actuator is responsive to the command. An example system includes where the system efficiency description circuit is further structured to determine a state of charge of the electrical power storage system, and where the shared load operating circuit is further structured to command the coupling actuator in response to the state of charge. ReferencingFIG.38, an example procedure includes an operation4202to power a shared load between a motor/generator and a vehicle driveline with the motor/generator by operating a coupling actuator to a first position; an operation4204to power the shared load and to charge an electrical power storage system coupled to the motor/generator from the driveline by operating the coupling actuator to a second position; and an operation4206to power the shared load with the driveline without charging the electrical power storage system from the driveline of the vehicle by operating the coupling actuator to a third position. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes where operating the coupling actuator includes an operation to operate an actuator for a planetary gear assembly; and/or operating the coupling actuator includes an operation to operate a clutch between the shared load and a load drive shaft of the planetary gear assembly. An example procedure further includes an operation to determine at least one efficiency value selected from the efficiency values consisting of: a driveline efficiency value (e.g., considering total rolling or load effective efficiency, prime mover, transmission, downstream driveline components, rolling friction, and/or wind resistance; and where efficiency is determined in terms of cost, time, and/or mission capability), a motor/generator efficiency powering value, and a motor/generator efficiency charging value; and further operating the coupling actuator in response to the at least one efficiency value; and/or an operation to determine a state of charge of the electrical power storage system, and further operating the coupling actuator in response to the state of charge. An example system includes a PTO device including a torque coupler between an accessory load drive shaft and a driveline of a vehicle; a one-way overrunning clutch interposed between the torque coupler and the accessory load drive shaft; and a motor/generator coupled to the accessory load drive shaft. An example one-way overrunning clutch allows torque transfer from the driveline to the load drive shaft when the driveline is turning faster (after applied gear ratios) than the load drive shaft, and allows slipping when the driveline is slower than the load drive shaft. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the torque coupler includes at least one coupler selected from the couplers consisting of: a chain, an idler gear engaging a countershaft gear on the driveline side and a driven gear on the accessory load drive shaft side, and a layshaft interposed between the driveline side and the accessory load drive shaft side. ReferencingFIG.39, an example procedure includes an operation4302to operate a PTO device to selectively power a shared load with one of a driveline and a motor/generator; an operation4304to power the motor/generator with a battery pack including a number of battery cell packs in a series configuration; an operation4306to determine the state of charge of individual battery cell packs within the battery pack; and an operation4308to level the state of charge between the individual battery cell packs within the battery pack. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to resistively discharge a higher charged battery cell pack of the battery pack. An example procedure further includes an operation to couple battery cell packs of the battery pack with a flyback converter with an isolation transformer. An example procedure further includes an operation to power a useful load with a higher charged battery cell pack of the battery pack; an operation to process the discharge power from the higher charged battery cell pack of the battery pack through power electronics to configure the discharge power to an electrical power format for the useful load. An example procedure further includes an operation to select a discharge operation in response to a state of charge difference between a higher charged battery cell pack of the battery pack and a lower charged battery cell pack of the battery pack. An example procedure further includes an operation to perform a service operation to replace at least a portion of the battery pack at 18 months of service; where the battery pack includes eight nominal 12V battery cell packs, including an operation to couple into two parallel packs of four series batteries, and where the service operation includes replacing one of the two parallel packs of batteries. An example procedure further includes an operation to perform a service operation to replace at least a portion of the battery pack at 24 months of service; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries, and where the service operation includes replacing one of the two parallel packs of batteries. ReferencingFIG.40, an example system includes a PTO device4404structured to selectively couple to a driveline of a vehicle; an electrical power storage system4408including a battery pack including a plurality of battery cell packs in a series configuration; a motor/generator4406electrically coupled to the electrical power storage system; a shared load4402selectively powered by one of the driveline or the motor/generator; and a controller4410, including: a battery state description circuit4412structured to determine a state of charge of each of the plurality of battery cell packs; and a battery management circuit4414structured to provide a charge leveling command in response to the state of charge between each of the plurality of battery cell packs. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a voltage sensor coupled to each of the plurality of battery cell packs, and where the battery state description circuit is further structured to determine the state of charge of each of the plurality of battery cell packs in response to a voltage value from each of the voltage sensors; and/or a temperature sensor coupled to each of the plurality of battery cell packs, and where the battery state description circuit4412is further structured to determine the state of charge of each of the plurality of battery cell packs in response to a temperature value from each of the temperature sensors. An example system includes where the battery management circuit4414is further structured to provide the charge leveling command as a resistive discharge command, the system further including a resistive discharge circuit4416for each of the plurality of battery cell packs, where the resistive discharge circuits are responsive to the resistive discharge command. An example system includes where the battery management circuit4414is further structured to provide the charge leveling command as a useful discharge command, the system further including a useful discharge circuit4418configured to power a useful load with a higher charged battery cell pack of the plurality of battery cell packs in response to the useful discharge command; where the useful discharge circuit4418further includes power electronics structured to configure discharge power from the higher charged battery cell pack of the plurality of battery cell packs to an electrical power format for the useful load; where each of the plurality of battery cell packs includes a nominal 12V lead-acid battery; where the battery pack includes four of the plurality of battery cell packs coupled in series; where the battery management circuit4414is further structured to provide the charge leveling command as a useful discharge command, the system further including a useful discharge circuit4418configured to power a useful load with a higher charged battery cell pack of the plurality of battery cell packs in response to the useful discharge command; where the useful load includes a nominal 12V load on the vehicle; where the useful discharge circuit4418further includes power electronics structured to configure discharge power from the higher charged battery cell pack of the plurality of battery cell packs to an electrical power format for the useful load; and/or where the useful load includes a nominal 48V load on the vehicle. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; an electrical power storage system including a battery pack including a plurality of battery cell packs in a series configuration; a motor/generator electrically coupled to an electrical power storage system; a shared load including a nominal 48V load, where the shared load is selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the shared load includes a 5 kW average load device. An example system includes where the shared load includes a 10 kW peak load device; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where each of the battery cell packs includes a lead-acid battery; where each of the lead-acid batteries includes an absorbent glass mat battery; where the shared load includes a 2.5 kW average load device; where the shared load includes a 5 kW peak load device; where the battery pack includes four nominal 12V battery cell packs coupled in series; where each of the battery cell packs includes a lead-acid battery; and/or where each of the lead-acid batteries includes an absorbent glass mat battery. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system, where the motor/generator includes a nominal 48V motor; a nominal 12V power supply electrically coupled to a field coil of the motor/generator; a shared load selectively powered by one of the driveline or the motor/generator; where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. ReferencingFIG.41, an example procedure includes an operation4502to energize a field coil of a motor/generator including a nominal 48V motor with a nominal 12V power supply (e.g., using a low voltage power supply to energize a higher voltage motor coil); an operation4504to selectively power a shared load with the motor/generator motor in a first operating mode, and with a driveline in a second operating mode; an operation4506to provide a first gear ratio between the motor/generator and the shared load in the first operating mode; and an operation4508to provide a second gear ratio between the driveline and the motor/generator in the second operating mode. An example system includes a PTO device structured to selectively couple to a countershaft of a transmission, where the PTO device couples to the countershaft with a PTO in axial alignment with the countershaft; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the countershaft or the motor/generator; and where the motor/generator is coupled to a first shaft and where the shared load is selectively coupled to a second shaft concentric with the first shaft. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the motor/generator is positioned between the transmission housing and the shared load, and where the second shaft is the inner shaft of the concentric shafts; and/or a planetary gear assembly configured to provide a first driven ratio to the shared load when powered by the countershaft, and to provide a second driven ratio to the shared load when powered by the motor/generator. An example system includes where the motor/generator is selectively coupled to the first shaft. An example system includes a planetary gear assembly configured to provide a first ratio between the motor/generator and the countershaft when power is transferred from the countershaft to the motor/generator, and to provide a second ratio between the motor/generator and the countershaft when power is transferred from the motor/generator to the countershaft. ReferencingFIG.30, an example system includes a PTO device3302structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a compressor selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the compressor to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a controller3304, the controller3304including a driving mode circuit3306structured to determine a current vehicle operating mode as one of a sleep mode or a motive mode; and a shared load operating mode circuit3308structured to command the coupling actuator to the first position in response to the sleep mode, and to command the coupling actuator to the second position in response to the motive mode. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a cement mixer selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the cement mixer to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the electrical power storage system is sized to provide a selected amount of off-line power for a selected amount of time; where the selected amount of off-line power includes at least one of the amounts consisting of: an amount of power drawn by the cement mixer, an amount of power to operate a climate control system of the vehicle, and an amount of power drawn by the cement mixer and the climate control system of the vehicle; and/or where the selected amount of time includes at least one of the amounts of time consisting of: 30 minutes, 2 hours, 8 hours, 10 hours, 12 hours, 24 hours, an amount of time correlating to a job schedule, and an amount of time correlating to a predetermined operating time of the cement mixer. An example system includes where the electrical power storage system includes a battery pack including a plurality of battery cell packs in a series configuration; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where the battery pack includes twelve nominal 12V battery cell packs, coupled into three parallel packs of four series batteries; and/or where the battery pack includes sixteen nominal 12V battery cell packs, coupled into four parallel packs of four series batteries. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a hydraulic motor selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the hydraulic motor to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the electrical power storage system is sized to provide a selected amount of off-line power for a selected amount of time; where the selected amount of off-line power includes at least one of the amounts consisting of: an amount of power drawn by the hydraulic motor, an amount of power to operate a climate control system of the vehicle, and an amount of power drawn by the hydraulic motor and the climate control system of the vehicle; and/or where the selected amount of time includes at least one of the amounts of time consisting of: 30 minutes, 2 hours, 8 hours, 10 hours, 12 hours, 24 hours, an amount of time correlating to a job schedule, and an amount of time correlating to a predetermined operating time of the hydraulic motor. An example system includes where the electrical power storage system includes a battery pack including a plurality of battery cell packs in a series configuration; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where the battery pack includes twelve nominal 12V battery cell packs, coupled into three parallel packs of four series batteries; and/or where the battery pack includes sixteen nominal 12V battery cell packs, coupled into four parallel packs of four series batteries. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a shared load including a 5 kW nominal load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the electrical power storage system includes a battery pack including a plurality of battery cell packs in a series configuration; and/or where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries. An example system includes where the PTO device is coupled to the driveline at a countershaft of a transmission. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system, where the electrical power storage system includes a battery pack including a plurality of nominal 12V battery cell packs in a series configuration; a low voltage power access including a nominal 12V tapped access of the battery pack; a shared load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a starter coupling between the electrical power storage system and the battery pack; and/or where the starter coupling includes one of a nominal 12V electrical coupling or a nominal 48V electrical coupling. An example system includes where the PTO device is structured to couple the motor/generator to the driveline at a selected gear ratio, and to transfer power from the motor/generator to the driveline; where the selected gear ratio includes a cranking gear ratio configured for a prime mover of the vehicle to accept cranking power from the motor/generator; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where the nominal 12V tapped access is from a single one of the two parallel packs; and/or where the nominal 12V tapped access is from both of the two parallel packs. An example system includes a PTO device that selectively couples to a driveline of a vehicle, a motor/generator electrically coupled to an electrical power storage system, a shared load selectively powered by the driveline or the motor/generator, and where the PTO device further includes a coupling actuator that couples the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the coupling actuator further couples the driveline to the motor/generator in the second position, where the coupling actuator includes a two-speed gear box, and/or where the coupling actuator couples the motor-generator to the shared load in a first gear ratio in the first position, and couples the motor-generator to the driveline in a second gear ratio in the second position. An example system includes where the coupling actuator couples the motor/generator to the driveline in a second gear ratio in the second position, and in a third gear ratio in a third position; where the coupling actuator further couples the motor/generator to the driveline in the second gear ratio in response to the driveline providing torque to the motor/generator; and/or where the coupling actuator further couples the motor/generator to the driveline in the third gear ratio in response to the motor/generator providing torque to the driveline. An example system includes where the coupling actuator further de-couples the motor/generator from the driveline in the first position. An example procedure includes an operation to selectively power a shared load with a motor/generator in a first operating mode, and with a driveline in a second operating mode; an operation to provide a first gear ratio between the motor/generator and the shared load in the first operating mode; and an operation to provide a second gear ratio between the driveline and the motor/generator in the second operating mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to power the motor/generator with the driveline in the second operating mode, and an operation to charge an electrical power storage system with the motor/generator in the second operating mode; an operation to power the motor/generator with the electrical power storage system in the first operating mode; an operation to power the driveline with the motor/generator in a third operating mode; and/or an operation to provide a third gear ratio between the motor/generator and the driveline in the third operating mode. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle, a motor/generator electrically coupled to an electrical power storage system, a shared load selectively powered by one of the driveline or the motor/generator, and where the PTO device further includes a coupling actuator including a planetary gear assembly, the coupling actuator structured to couple the shared load to the motor/generator at a first gear ratio in a first position of the planetary gear assembly, and to couple the shared load to the driveline at a second gear ratio in a second position of the planetary gear assembly. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the first position of the planetary gear assembly includes a neutral position that de-couples the driveline from both of the motor/generator and the shared load. An example system includes where the shared load is selectively rotationally coupled to a load drive shaft, and where the motor/generator is selectively rotationally coupled to the load drive shaft through a second planetary reduction gear, and/or where the shared load is selectively rotationally coupled to the load drive shaft through at least one of a clutch and a third planetary gear. An example system includes where the coupling actuator is further structured to couple the driveline to the motor/generator at a third gear ratio in a third position of the planetary gear assembly, where the second position of the planetary gear assembly includes a ring gear of the planetary gear assembly engaging a driven gear of the planetary gear assembly, where the first position of the planetary gear assembly includes a free-wheeling position of the planetary gear assembly, where the third position of the planetary gear assembly includes engaging a second ring gear of the planetary gear assembly with a stationary gear of the planetary gear assembly, and/or where the ring gear includes an inner ring gear, and where the second ring gear includes an outer ring gear. An example procedure includes an operation to selectively power a shared load between a driveline of a vehicle and a motor/generator, an operation to selectively power including positioning a planetary gear assembly into a first position de-coupling the driveline from the shared load, thereby powering the shared load with the motor/generator; and an operation to position the planetary gear assembly into a second position coupling the driveline to the shared load, thereby powering the shared load with the driveline. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to power the motor/generator with the driveline in the second position of the planetary gear assembly, thereby charging an electrical power storage system with the motor/generator; an operation to selectively power the driveline with the motor/generator; an operation to selectively power the driveline includes positioning the planetary gear assembly into one of the second position or a third position, thereby coupling the driveline to the motor/generator, and where a gear ratio between the driveline and the motor/generator in the second position is distinct from a gear ratio between the driveline and the motor/generator in the third position; and/or an operation to de-couple the shared load from the motor/generator during the powering the driveline with the motor/generator. An example system includes a PTO device structured to selectively couple to a transmission of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of a driveline of the vehicle or the motor/generator, where the PTO device further includes a coupling actuator structured to couple the driveline to the motor/generator in a first position, and to the shared load in a second position; and where the PTO device includes a housing having a first interface coupled to the motor/generator and a second interface coupled to the shared load, and where the first interface is displaced at least 90 degrees from the second interface. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the first interface is in an opposite direction from the second interface. An example system includes a load drive shaft disposed in the PTO device, where a first end of the load drive shaft is positioned toward the first interface and where a second end of the load drive shaft is positioned toward the second interface. An example system includes a first one of the first interface or the second interface is positioned toward a front of the vehicle, and where the other one of the first interface or second interface is positioned toward a rear of the vehicle. An example system includes the housing further includes a third interface coupled to the transmission, and where the third interface includes an orientation perpendicular to the load drive shaft. An example system includes the housing further includes a T-shape. An example system includes the housing further including a third interface coupled to a side PTO interface of the transmission, and/or the side PTO interface includes an 8-bolt PTO interface. An example system includes the housing further including a third interface coupled to the transmission, and where the PTO device further includes a driveline coupling device structured to selectively access power from the driveline; the driveline coupling device including an idler gear engaging a countershaft gear of the transmission; the driveline coupling device including a chain engaging a countershaft gear of the transmission; the driveline coupling device including a splined shaft engaging a countershaft of the transmission; the driveline coupling device including a layshaft engaging a gear of the transmission; and/or the driveline coupling device including a chain engaging a gear of the transmission. An example system includes a PTO device having a coupling actuator configured to couple a shared load to a motor/generator in a first position, and to couple the shared load to a driveline of a vehicle in a second position; a controller including a driving mode circuit structured to determine a current vehicle operating mode as one of a sleep mode or a motive mode; and a shared load operating mode circuit structured to command the coupling actuator to the first position in response to the sleep mode, and to command the coupling actuator to the second position in response to the motive mode. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes the coupling actuator further configured to de-couple the driveline from the shared load and the motor/generator in the first position. An example system includes where the coupling actuator is further configured to couple the driveline of the vehicle to the motor/generator in a third position and/or where the driving mode circuit is further structured to determine the current vehicle operating mode as a creep mode, and where the shared load operating mode circuit is further structured to command the coupling actuator to the third position in response to the creep mode. An example system includes a load drive shaft selectively coupled to the shared load, where the motor/generator powers the load drive shaft in the first position, and where the driveline powers the load drive shaft in the second position; a shared load coupling actuator structured to selectively de-couple the shared load from the load drive shaft; and where the shared load operating mode circuit is further structured to command the shared load coupling actuator to de-couple the shared load from the load drive shaft in response to the creep mode. An example system includes where the driving mode circuit is further structured to determine the current vehicle operating mode as a crank mode, and where the shared load operating mode circuit is further structured to command the coupling actuator to the third position in response to the crank mode. An example system including where the coupling actuator is further configured to selectively couple the motor/generator to the driveline of the vehicle in the second position; an electrical stored power circuit structured to determine a state of charge of an electrical power storage system, and where the shared load operating mode circuit is further structured to command the coupling actuator to couple the motor/generator to the driveline of the vehicle in the second position in response to the state of charge of the electrical power storage system; and/or the coupling actuator is further configured to couple the driveline of the vehicle to the motor/generator in a third position, and where a first gear ratio between the motor/generator and the driveline of the vehicle in the second position is distinct from a second gear ratio between the motor/generator and the driveline of the vehicle in the third position. An example procedure includes an operation to determine a current vehicle operating mode as one of a sleep mode or a motive mode; an operation to command a coupling actuator to couple a shared load to a driveline of a vehicle in response to the motive mode; and an operation to command the coupling actuator to couple the shared load to a motor/generator in response to the sleep mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to de-couple the driveline of the vehicle from both of the shared load and the motor/generator in response to the sleep mode. An example procedure further includes an operation to determine the current vehicle operating mode as a creep mode, and commanding the coupling actuator to couple the motor/generator to the driveline in response to the creep mode. An example procedure further includes an operation to determine the current vehicle operating mode as a crank mode, and commanding the coupling actuator to couple the motor/generator to the driveline in response to the crank mode. An example procedure further includes an operation to selectively couple the driveline to the motor/generator in response to the motive mode; an operation to determine a state of charge of an electrical power storage system, and where the selectively coupling the driveline to the motor/generator is further in response to the state of charge; an operation to determine the current vehicle operating mode as one of a crank mode or a creep mode, an operation to command the coupling actuator to couple the motor/generator to the driveline in response to the one of the crank mode or the creep mode; and/or an operation to command the coupling actuator to couple the motor/generator to the driveline at a first gear ratio in response to the motive mode, and to couple the motor/generator to the driveline at a second gear ratio in response to the one of the crank mode or the creep mode, and where the first gear ratio is distinct from the second gear ratio. An example includes a PTO device having a coupling actuator configured to couple a shared load to a motor/generator in a first position, to couple the shared load to a driveline of a vehicle in a second position, and to couple the motor/generator to the driveline of the vehicle in a third position; a controller, including a driving mode circuit structured to determine a current vehicle operating mode as one of a sleep mode, a motive mode, or a creep mode; and a shared load operating mode circuit structured to command the coupling actuator to the first position in response to the sleep mode, to command the coupling actuator to the second position in response to the motive mode, and to command the coupling actuator to the third position in response to the creep mode. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the controller further includes a reverse enforcement circuit structured to determine a reverse gearing position, and where the shared load operating mode circuit is further structured to command the coupling actuator to the third position in response to the reverse gearing position; where the reverse enforcement circuit is further structured to determine the reverse gearing position in response to a transmission state value; and/or where the reverse enforcement circuit is further structured to determine the reverse gearing position in response to a creep permission value. An example system includes where the shared load operating mode circuit is further structured to provide a motor/generator direction command value in response to the creep mode, and where the motor/generator is responsive to the motor/generator direction command value; where the driving mode circuit is further structured to determine the current vehicle operating mode as a crank mode, and where the shared load operating mode circuit is further structured to command the coupling actuator to the third position in response to the crank mode; the shared load operating mode circuit is further structured to provide the motor/generator direction command value further in response to the crank mode; and/or where the shared load operating mode circuit is further structured to provide the motor/generator direction command value as a first direction in response to the crank mode, and as a second direction in response to the creep mode. An example system includes where a first rotational coupling direction between the motor/generator and the driveline in the second position is opposite a second rotational coupling direction between the motor/generator and the driveline in the third position. An example procedure includes an operation to determine a current vehicle operating mode as one of a sleep mode, a motive mode, or a creep mode; an operation to command a coupling actuator to a first position coupling a shared load with a motor/generator in response to the sleep mode; an operation to command the coupling actuator to a second position coupling the shared load with a driveline of a vehicle in response to the motive mode; and an operation to command the coupling actuator to a third position coupling the motor/generator with the driveline of the vehicle in response to the creep mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to determine a reverse gearing position, and commanding the coupling actuator to the third position further in response to the reverse gearing position; an operation to determine the reverse gearing position in response to a transmission state value; an operation to determine the reverse gearing position in response to a creep permission value; an operation to provide a motor/generator direction command value in response to the creep mode; an operation to determine the current vehicle operating mode as a crank mode, and commanding the coupling actuator to the third position in response to the crank mode; and/or an operation to provide the motor/generator direction command value as a first direction in response to the creep mode, and as a second direction in response to the crank mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to determine a reverse gearing position; an operation to command the coupling actuator to the third position in response to a predetermined correlation between: one of the crank mode or the creep mode; and the reverse gearing position. An example system includes a countershaft transmission, having an input shaft coupled to a prime mover, an output shaft coupled to a motive driveline, and a countershaft selectively transferring torque from the input shaft to the output shaft at selected gear ratios; a PTO gear including a transmission housing access at a selected gear on the countershaft; a PTO device structured to selectively couple to the selected gear on the countershaft; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the selected gear or the motor/generator; and where the PTO device further includes a sliding clutch structured to couple the shared load to the motor/generator in a first position, and to the selected gear in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a main shaft coupled to the output shaft, and where the countershaft transfers torque to the output shaft through the main shaft. An example system includes where the selected gear on the countershaft corresponds to a direct drive gear of the input shaft. An example system includes where the transmission housing access includes an 8-bolt PTO interface. An example system includes where the PTO device further includes an idler gear engaging the selected gear. An example system includes a countershaft transmission, having an input shaft coupled to a prime mover; an output shaft coupled to a motive driveline; and a countershaft selectively transferring torque from the input shaft to the output shaft at selected gear ratios; a PTO access including a rear transmission housing access positioned at the countershaft; a PTO device structured to selectively couple to the countershaft; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the selected gear or the motor/generator; and where the PTO device further includes planetary gear assembly structured to couple the shared load to the motor/generator in a first position, and to the countershaft in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the PTO device further includes a splined shaft engaging the countershaft. An example system includes a clutch interposed between the motor/generator and the planetary gear assembly, where the clutch is structured to selectively disconnect the planetary gear assembly from the countershaft. An example system includes where the planetary gear assembly is further structured to further couple the motor/generator to the countershaft in the second position, and/or where the planetary gear assembly is further structured to couple the motor/generator to the countershaft in a third position, to provide a first gear ratio between the motor/generator and the countershaft in the second position, and to provide a second gear ratio between the motor/generator and the countershaft in the third position. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator at a first selected ratio in a first position, and to couple the shared load to the driveline at a second selected ratio in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the coupling actuator is further structured to couple the motor/generator to the driveline at a third selected ratio in the second position. An example system includes where the coupling actuator is further structured to couple the motor/generator to the driveline at a fourth selected ratio in a third position; a load drive shaft selectively coupled to the shared load, where the motor/generator powers the load drive shaft in the first position, and where the driveline powers the load drive shaft in the second position; where the coupling actuator is further structured to de-couple the shared load from the load drive shaft in the third position; and/or where the coupling actuator is further structured to de-couple the load drive shaft from the driveline in the first position. An example system includes where the motor/generator is further structured to charge the electrical power storage system in the second position. An example procedure includes an operation to selectively power a shared load with a motor/generator in a first operating mode and with a driveline of a vehicle in a second operating mode, where the selectively power includes an operation to couple the driveline to the shared load at a first selected ratio and to the motor/generator at a second selected ratio in the first operating mode; and an operation to couple the motor/generator to the shared load at a third selected ratio in the second operating mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to selectively power the driveline with the motor/generator in a third operating mode at a fourth selected ratio; where the third operating mode includes a creep mode, and an operation to power the driveline with the motor/generator provides motive power to the driveline; an operation to selectively power the driveline with the motor/generator in a fourth operating mode at a fifth selected ratio; and/or where the fourth operating mode includes a crank mode, and an operation to power the driveline with the motor/generator provides cranking power to start a prime mover coupled to the driveline. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a power flow control device structured to power a shared load with a selected one of the driveline or the motor/generator; where the power flow control device is further structured to selectively transfer power between the motor/generator and the driveline; and where the power flow control device is further structured to de-couple both of the motor/generator and the shared load from the driveline when the motor/generator powers the shared load. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the power flow control device is further structured to power the motor/generator with the driveline to charge the electrical power storage system. An example system includes where the electrical power storage system is sized to provide a selected amount of off-line power for a selected amount of time; where the selected amount of off-line power includes at least one of the amounts consisting of: an amount of power drawn by the shared load, an amount of power to operate a climate control system of the vehicle, an amount of power to operate a climate control system of the vehicle plus vehicle living space accessories, and an amount of power to operate accessories of a vehicle; and/or where the selected amount of time includes at least one of the amounts of time consisting of: 30 minutes, 2 hours, 8 hours, 10 hours, 12 hours, and 24 hours. An example system includes power electronics disposed between the electrical power storage system and at least one accessory of the vehicle, where the power electronics are structured to configure electrical power provided from the electrical power storage to an electrical power format for the at least one accessory; and/or where each of the at least one accessories comprise one of a nominal 12V DC accessory and a nominal 110V AC accessory. An example system includes 8 where the power flow control device is further structured to de-couple the motor/generator from the shared load when the motor/generator powers the driveline; and/or where the power flow control device is further structured to provide a first gear ratio between the motor/generator and the driveline when powering the motor/generator from the driveline, and to provide a second gear ratio between the motor/generator and the driveline when powering the driveline with the motor/generator. An example system includes where the power flow control device includes a planetary gear assembly structured to route power between the shared load, the motor/generator, and the driveline; where the planetary gear assembly further includes a driven gear coupled to a countershaft gear; and/or where the power flow control device further includes an idler gear interposed between the driven gear and the countershaft gear. An example procedure includes an operation to selectively power a shared load with one of a motor/generator or a driveline of a vehicle; an operation to selectively couple the motor/generator to the driveline to provide a selected one of powering the driveline with the motor/generator or powering the motor/generator with the driveline; and an operation to de-couple the motor/generator from the driveline in response to powering the shared load with the motor/generator. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to couple the motor/generator to the driveline to charge an electrical power storage system; and operation to power an off-line device with at least one of the motor/generator or the electrical power storage system in response to a prime mover of the vehicle being shut down; an operation to configure electrical power from the electrical power storage system to an electrical power format for the off-line device; where an operation to sharing load includes a climate control device for the vehicle, and an operation to selectively power the shared load with the motor/generator is in response to the prime mover of the vehicle being shut down. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a controller, including: a driving mode circuit structured to determine a current vehicle operating mode as one of a motive power mode or a charging mode; a PTO coupling circuit structured to provide a motive power coupling command in response to the motive power mode, and to provide a charge coupling command in response to the charging mode; and where the PTO device includes a coupling actuator responsive to the motive power coupling command to couple the motor/generator to the driveline of the vehicle in a first gear ratio, and responsive to the charge coupling command to couple the motor/generator to the driveline of the vehicle in a second gear ratio. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the motive power mode includes one of a crank mode, a creep mode, or a launch mode. An example system includes where the driving mode circuit is further structured to determine the charging mode in response to a state of charge of the electrical power storage system. An example system includes an accessory, and where the coupling actuator selectively couples the accessory to one of the driveline or the motor/generator; and/or where the driving mode circuit is further structured to determine the current vehicle operating mode as a sleep mode, where the PTO coupling circuit is further structured to provide a sleep power command in response to the sleep mode, and where the coupling actuator is further responsive to couple the motor/generator to the accessory in response to the sleep power command. An example system includes a motor/generator operating profile circuit structured to determine a motor/generator efficient operating point, and where the PTO coupling circuit is further structured to adjust the charge coupling command in response to the motor/generator efficient operating point, and where the coupling actuator is further responsive to the adjusted charge coupling command to couple the motor/generator to the driveline of the vehicle in a selected one of the first gear ratio and the second gear ratio. An example procedure includes an operation to determine a current vehicle operating mode as one of a motive power mode or a charging mode; an operation to couple a motor/generator to a driveline of a vehicle in a first gear ratio in response to the motive power mode; and an operation to couple the motor/generator to the driveline of the vehicle in a second gear ratio in response to the charging mode. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to determine a state of charge of an electrical power storage system electrically coupled to the motor/generator, and determining the vehicle operating mode as the charging mode further in response to the state of charge of the electrical power storage system; an operation to power an accessory from a selected one of the driveline and the motor/generator; an operation to determine the vehicle operating mode as a sleep mode, and selecting the motor/generator to power the accessory in response to the sleep mode; an operation to select the one of the driveline and the motor/generator in response to the state of charge of the electrical power storage system; and/or an operation to determine a motor/generator efficient operating point, and coupling the motor/generator to the driveline of the vehicle in a selected one of the first gear ratio and the second gear ratio further in response to the motor/generator efficient operating point. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple: the shared load to the motor/generator in a first position; the shared load and the motor/generator to the driveline in a second position; and the shared load to the driveline in a third position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the coupling actuator includes a planetary gear assembly having a planetary gear with three positions, where a first position of the planetary gear couples the motor/generator to the driveline in a first gear ratio, where a second position of the planetary gear couples the motor/generator to the driveline in a second gear ratio, and where a third position de-couples the motor/generator from the driveline; a load drive shaft, where the coupling actuator further includes at least one of a clutch and a second planetary gear, and where the at least one of the clutch and the second planetary gear couple the shared load to the load drive shaft in a first position, and de-couple the shared load from the load drive shaft in a second position; and/or a third planetary gear coupling the motor/generator to the load drive shaft. An example system includes a controller, the controller including a system efficiency description circuit structured to determine at least one efficiency value selected from the efficiency values consisting of: a driveline efficiency value, a motor/generator efficiency powering value, and a motor/generator efficiency charging value; and a shared load operating circuit structured to command the coupling actuator in response to the at least one efficiency value; and where the coupling actuator is responsive to the command. An example system includes where the system efficiency description circuit is further structured to determine a state of charge of the electrical power storage system, and where the shared load operating circuit is further structured to command the coupling actuator in response to the state of charge. An example procedure includes an operation to power a shared load between a motor/generator and a vehicle driveline with the motor/generator by operating a coupling actuator to a first position; an operation to power the shared load and charging an electrical power storage system coupled to the motor/generator from the driveline by operating the coupling actuator to a second position; and an operation to power the shared load with the driveline without charging the electrical power storage system from the driveline of the vehicle by operating the coupling actuator to a third position. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes where operating the coupling actuator includes an operation to operate an actuator for a planetary gear assembly; and/or operating the coupling actuator includes an operation to operate a clutch between the shared load and a load drive shaft of the planetary gear assembly. An example procedure further includes an operation to determine at least one efficiency value selected from the efficiency values consisting of: a driveline efficiency value, a motor/generator efficiency powering value, and a motor/generator efficiency charging value; and further operating the coupling actuator in response to the at least one efficiency value; and/or an operation to determine a state of charge of the electrical power storage system, and further operating the coupling actuator in response to the state of charge. An example system includes a PTO device including a torque coupler between an accessory load drive shaft and a driveline of a vehicle; a one-way overrunning clutch interposed between the torque coupler and the accessory load drive shaft; and a motor/generator coupled to the accessory load drive shaft. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the torque coupler includes at least one coupler selected from the couplers consisting of: a chain, an idler gear engaging a countershaft gear on the driveline side and a driven gear on the accessory load drive shaft side, and a layshaft interposed between the driveline side and the accessory load drive shaft side. An example procedure includes an operation to operate a PTO device to selectively power a shared load with one of a driveline and a motor/generator; an operation to power the motor/generator with a battery pack including a plurality of battery cell packs in a series configuration; an operation to determine the state of charge of individual battery cell packs within the battery pack; and an operation to level the state of charge between the individual battery cell packs within the battery pack. Certain further aspects of an example procedure are described following, any one or more of which may be present in certain embodiments. An example procedure further includes an operation to resistively discharge a higher charged battery cell pack of the battery pack. An example procedure further includes an operation to couple battery cell packs of the battery pack with a flyback converter with an isolation transformer. An example procedure further includes an operation to power a useful load with a higher charged battery cell pack of the battery pack; an operation to process the discharge power from the higher charged battery cell pack of the battery pack through power electronics to configure the discharge power to an electrical power format for the useful load. An example procedure further includes an operation to select a discharge operation in response to a state of charge difference between a higher charged battery cell pack of the battery pack and a lower charged battery cell pack of the battery pack. An example procedure further includes an operation to perform a service operation to replace at least a portion of the battery pack at 18 months of service; where the battery pack includes eight nominal 12V battery cell packs, including an operation to couple into two parallel packs of four series batteries, and where the service operation includes replacing one of the two parallel packs of batteries. An example procedure further includes an operation to perform a service operation to replace at least a portion of the battery pack at 24 months of service; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries, and where the service operation includes replacing one of the two parallel packs of batteries. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; an electrical power storage system including a battery pack including a plurality of battery cell packs in a series configuration; a motor/generator electrically coupled to the electrical power storage system; a shared load selectively powered by one of the driveline or the motor/generator; and a controller, including: a battery state description circuit structured to determine a state of charge of each of the plurality of battery cell packs; and a battery management circuit structured to provide a charge leveling command in response to the state of charge between each of the plurality of battery cell packs. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a voltage sensor coupled to each of the plurality of battery cell packs, and where the battery state description circuit is further structured to determine the state of charge of each of the plurality of battery cell packs in response to a voltage value from each of the voltage sensors; and/or a temperature sensor coupled to each of the plurality of battery cell packs, and where the battery state description circuit is further structured to determine the state of charge of each of the plurality of battery cell packs in response to a temperature value from each of the temperature sensors. An example system includes where the battery management circuit is further structured to provide the charge leveling command as a resistive discharge command, the system further including a resistive discharge circuit for each of the plurality of battery cell packs, where the resistive discharge circuits are responsive to the resistive discharge command. An example system includes where the battery management circuit is further structured to provide the charge leveling command as a useful discharge command, the system further including a useful discharge circuit configured to power a useful load with a higher charged battery cell pack of the plurality of battery cell packs in response to the useful discharge command; where the useful discharge circuit further includes power electronics structured to configure discharge power from the higher charged battery cell pack of the plurality of battery cell packs to an electrical power format for the useful load; where each of the plurality of battery cell packs includes a nominal 12V lead-acid battery; where the battery pack includes four of the plurality of battery cell packs coupled in series; where the battery management circuit is further structured to provide the charge leveling command as a useful discharge command, the system further including a useful discharge circuit configured to power a useful load with a higher charged battery cell pack of the plurality of battery cell packs in response to the useful discharge command; where the useful load includes a nominal 12V load on the vehicle; where the useful discharge circuit further includes power electronics structured to configure discharge power from the higher charged battery cell pack of the plurality of battery cell packs to an electrical power format for the useful load; and/or where the useful load includes a nominal 48V load on the vehicle. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; an electrical power storage system including a battery pack including a plurality of battery cell packs in a series configuration; a motor/generator electrically coupled to an electrical power storage system; a shared load including a nominal 48V load, where the shared load is selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the shared load includes a 5 kW average load device. An example system includes where the shared load includes a 10 kW peak load device; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where each of the battery cell packs includes a lead-acid battery; where each of the lead-acid batteries includes an absorbent glass mat battery; where the shared load includes a 2.5 kW average load device; where the shared load includes a 5 kW peak load device; where the battery pack includes four nominal 12V battery cell packs coupled in series; where each of the battery cell packs includes a lead-acid battery; and/or where each of the lead-acid batteries includes an absorbent glass mat battery. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system, where the motor/generator includes a nominal 48V motor; a nominal 12V power supply electrically coupled to a field coil of the motor/generator; a shared load selectively powered by one of the driveline or the motor/generator; where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. An example procedure includes an operation to energize a field coil of a motor/generator including a nominal 48V motor with a nominal 12V power supply; an operation to selectively power a shared load with the motor/generator motor in a first operating mode, and with a driveline in a second operating mode; an operation to provide a first gear ratio between the motor/generator and the shared load in the first operating mode; and an operation to provide a second gear ratio between the driveline and the motor/generator in the second operating mode. An example system includes a PTO device structured to selectively couple to a countershaft of a transmission, where the PTO device couples to the countershaft with a PTO in axial alignment with the countershaft; a motor/generator electrically coupled to an electrical power storage system; a shared load selectively powered by one of the countershaft or the motor/generator; and where the motor/generator is coupled to a first shaft and where the shared load is selectively coupled to a second shaft concentric with the first shaft. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the motor/generator is positioned between the transmission housing and the shared load, and where the second shaft is the inner shaft of the concentric shafts; and/or a planetary gear assembly configured to provide a first driven ratio to the shared load when powered by the countershaft, and to provide a second driven ratio to the shared load when powered by the motor/generator. An example system includes where the motor/generator is selectively coupled to the first shaft. An example system includes a planetary gear assembly configured to provide a first ratio between the motor/generator and the countershaft when power is transferred from the countershaft to the motor/generator, and to provide a second ratio between the motor/generator and the countershaft when power is transferred from the motor/generator to the countershaft. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a compressor selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the compressor to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a controller, the controller including a driving mode circuit structured to determine a current vehicle operating mode as one of a sleep mode or a motive mode; and a shared load operating mode circuit structured to command the coupling actuator to the first position in response to the sleep mode, and to command the coupling actuator to the second position in response to the motive mode. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a cement mixer selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the cement mixer to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the electrical power storage system is sized to provide a selected amount of off-line power for a selected amount of time; where the selected amount of off-line power includes at least one of the amounts consisting of: an amount of power drawn by the cement mixer, an amount of power to operate a climate control system of the vehicle, and an amount of power drawn by the cement mixer and the climate control system of the vehicle; and/or where the selected amount of time includes at least one of the amounts of time consisting of: 30 minutes, 2 hours, 8 hours, 10 hours, 12 hours, 24 hours, an amount of time correlating to a job schedule, and an amount of time correlating to a predetermined operating time of the cement mixer. An example system includes where the electrical power storage system includes a battery pack including a plurality of battery cell packs in a series configuration; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where the battery pack includes twelve nominal 12V battery cell packs, coupled into three parallel packs of four series batteries; and/or where the battery pack includes sixteen nominal 12V battery cell packs, coupled into four parallel packs of four series batteries. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a hydraulic motor selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the hydraulic motor to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the electrical power storage system is sized to provide a selected amount of off-line power for a selected amount of time; where the selected amount of off-line power includes at least one of the amounts consisting of: an amount of power drawn by the hydraulic motor, an amount of power to operate a climate control system of the vehicle, and an amount of power drawn by the hydraulic motor and the climate control system of the vehicle; and/or where the selected amount of time includes at least one of the amounts of time consisting of: 30 minutes, 2 hours, 8 hours, 10 hours, 12 hours, 24 hours, an amount of time correlating to a job schedule, and an amount of time correlating to a predetermined operating time of the hydraulic motor. An example system includes where the electrical power storage system includes a battery pack including a plurality of battery cell packs in a series configuration; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where the battery pack includes twelve nominal 12V battery cell packs, coupled into three parallel packs of four series batteries; and/or where the battery pack includes sixteen nominal 12V battery cell packs, coupled into four parallel packs of four series batteries. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system; a shared load including a 5 kW nominal load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes where the electrical power storage system includes a battery pack including a plurality of battery cell packs in a series configuration; and/or where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries. An example system includes where the PTO device is coupled to the driveline at a countershaft of a transmission. An example system includes a PTO device structured to selectively couple to a driveline of a vehicle; a motor/generator electrically coupled to an electrical power storage system, where the electrical power storage system includes a battery pack including a plurality of nominal 12V battery cell packs in a series configuration; a low voltage power access including a nominal 12V tapped access of the battery pack; a shared load selectively powered by one of the driveline or the motor/generator; and where the PTO device further includes a coupling actuator structured to couple the shared load to the motor/generator in a first position, and to the driveline in a second position. Certain further aspects of an example system are described following, any one or more of which may be present in certain embodiments. An example system includes a starter coupling between the electrical power storage system and the battery pack; and/or where the starter coupling includes one of a nominal 12V electrical coupling or a nominal 48V electrical coupling. An example system includes where the PTO device is structured to couple the motor/generator to the driveline at a selected gear ratio, and to transfer power from the motor/generator to the driveline; where the selected gear ratio includes a cranking gear ratio configured for a prime mover of the vehicle to accept cranking power from the motor/generator; where the battery pack includes eight nominal 12V battery cell packs, coupled into two parallel packs of four series batteries; where the nominal 12V tapped access is from a single one of the two parallel packs; and/or where the nominal 12V tapped access is from both of the two parallel packs. The programmed methods and/or instructions described herein may be deployed in part or in whole through a machine that executes computer instructions on a computer-readable media, program codes, and/or instructions on a processor or processors. “Processor” used herein is synonymous with the plural “processors” and the two terms may be used interchangeably unless context clearly indicates otherwise. The processor may be part of a server, client, network infrastructure, mobile computing platform, stationary computing platform, or other computing platform. A processor may be any kind of computational or processing device capable of executing program instructions, codes, binary instructions and the like. The processor may be or include a signal processor, digital processor, embedded processor, microprocessor or any variant such as a co-processor (math co-processor, graphic co-processor, communication co-processor and the like) and the like that may directly or indirectly facilitate execution of program code or program instructions stored thereon. In addition, the processor may enable execution of multiple programs, threads, and codes. The threads may be executed simultaneously to enhance the performance of the processor and to facilitate simultaneous operations of the application. By way of implementation, methods, program codes, program instructions and the like described herein may be implemented in one or more thread. The thread may spawn other threads that may have assigned priorities associated with them; the processor may execute these threads based on priority or any other order based on instructions provided in the program code. The processor may include memory that stores methods, codes, instructions and programs as described herein and elsewhere. The processor may access a storage medium through an interface that may store methods, codes, and instructions as described herein and elsewhere. The storage medium associated with the processor for storing methods, programs, codes, program instructions or other type of instructions capable of being executed by the computing or processing device may include but may not be limited to one or more of a CD-ROM, DVD, memory, hard disk, flash drive, RAM, ROM, cache and the like. A processor may include one or more cores that may enhance speed and performance of a multiprocessor. In embodiments, the process may be a dual core processor, quad core processors, other chip-level multiprocessor and the like that combine two or more independent cores (called a die). The methods and systems described herein may be deployed in part or in whole through a machine that executes computer readable instructions on a server, client, firewall, gateway, hub, router, or other such computer and/or networking hardware. The computer readable instructions may be associated with a server that may include a file server, print server, domain server, Internet server, intranet server and other variants such as secondary server, host server, distributed server and the like. The server may include one or more of memories, processors, computer readable media, storage media, ports (physical and virtual), communication devices, and interfaces capable of accessing other servers, clients, machines, and devices through a wired or a wireless medium, and the like. The methods, programs, or codes as described herein and elsewhere may be executed by the server. In addition, other devices required for execution of methods as described in this application may be considered as a part of the infrastructure associated with the server. The server may provide an interface to other devices including, without limitation, clients, other servers, printers, database servers, print servers, file servers, communication servers, distributed servers and the like. Additionally, this coupling and/or connection may facilitate remote execution of program across the network. The networking of some or all of these devices may facilitate parallel processing of a program or method at one or more location without deviating from the scope. In addition, any of the devices attached to the server through an interface may include at least one storage medium capable of storing methods, programs, code, and/or instructions. A central repository may provide program instructions to be executed on different devices. In this implementation, the remote repository may act as a storage medium for program code, instructions, and programs. The computer readable instructions may be associated with a client that may include a file client, print client, domain client, Internet client, intranet client and other variants such as secondary client, host client, distributed client and the like. The client may include one or more of memories, processors, computer readable media, storage media, ports (physical and virtual), communication devices, and interfaces capable of accessing other clients, servers, machines, and devices through a wired or a wireless medium, and the like. The methods, programs, or codes as described herein and elsewhere may be executed by the client. In addition, other devices required for execution of methods as described in this application may be considered as a part of the infrastructure associated with the client. The client may provide an interface to other devices including, without limitation, servers, other clients, printers, database servers, print servers, file servers, communication servers, distributed servers and the like. Additionally, this coupling and/or connection may facilitate remote execution of a program across the network. The networking of some or all of these devices may facilitate parallel processing of a program or method at one or more location without deviating from the scope. In addition, any of the devices attached to the client through an interface may include at least one storage medium capable of storing methods, programs, applications, code and/or instructions. A central repository may provide program instructions to be executed on different devices. In this implementation, the remote repository may act as a storage medium for program code, instructions, and programs. The methods and systems described herein may be deployed in part or in whole through network infrastructures. The network infrastructure may include elements such as computing devices, servers, routers, hubs, firewalls, clients, personal computers, communication devices, routing devices and other active and passive devices, modules and/or components as known in the art. The computing and/or non-computing device(s) associated with the network infrastructure may include, apart from other components, a storage medium such as flash memory, buffer, stack, RAM, ROM and the like. The processes, methods, program codes, instructions described herein and elsewhere may be executed by one or more of the network infrastructural elements. The methods, program codes, and instructions described herein and elsewhere may be implemented on a cellular network having multiple cells. The cellular network may either be frequency division multiple access (FDMA) network or code division multiple access (CDMA) network. The cellular network may include mobile devices, cell sites, base stations, repeaters, antennas, towers, and the like. The cell network may be a GSM, GPRS, 3G, 4G, LTE, EVDO, mesh, or other networks types. The methods, programs, codes, and instructions described herein and elsewhere may be implemented on or through mobile devices. The mobile devices may include navigation devices, vehicle remote network access devices, cell phones, mobile phones, mobile personal digital assistants, laptops, palmtops, netbooks, pagers, electronic books readers, music players and the like. These devices may include, apart from other components, a storage medium such as a flash memory, buffer, RAM, ROM, and one or more computing devices. The computing devices associated with mobile devices may be enabled to execute program codes, methods, and instructions stored thereon. Alternatively, the mobile devices may be configured to execute instructions in collaboration with other devices. The mobile devices may communicate with base stations interfaced with servers and configured to execute program codes. The mobile devices may communicate on a peer to peer network, mesh network, or other communications network. The program code may be stored on the storage medium associated with the server and executed by a computing device embedded within the server. The base station may include a computing device and a storage medium. The storage device may store program codes and instructions executed by the computing devices associated with the base station. The computer instructions, program codes, and/or instructions may be stored and/or accessed on machine readable media that may include: computer components, devices, and recording media that retain digital data used for computing for some interval of time; semiconductor storage known as random access memory (RAM); mass storage typically for more permanent storage, such as optical discs, forms of magnetic storage like hard disks, tapes, drums, cards and other types; processor registers, cache memory, volatile memory, non-volatile memory; optical storage such as CD, DVD; removable media such as flash memory (e.g. USB sticks or keys), floppy disks, magnetic tape, paper tape, punch cards, standalone RAM disks, Zip drives, removable mass storage, off-line, and the like; other computer memory such as dynamic memory, static memory, read/write storage, mutable storage, read only, random access, sequential access, location addressable, file addressable, content addressable, network attached storage, storage area network, bar codes, magnetic ink, and the like. The methods and systems described herein may transform physical and/or or intangible items from one state to another. The methods and systems described herein may also transform data representing physical and/or intangible items from one state to another. The elements described and depicted herein, including in procedure descriptions, methods, flow charts, and block diagrams imply logical boundaries between the elements. However, any operations described herein may be divided in whole or part, combined in whole or part, re-ordered in whole or part, and/or have certain operations omitted in certain embodiments. As such, the depiction and/or description of an order for various steps should not be understood to require a particular order of execution for those steps, unless required by a particular application, or explicitly stated or otherwise clear from the context. Operations described herein may be implemented by a computing device having access to computer executable instructions stored on a computer readable media, wherein the computing device executing the instructions thereby performs one or more aspects of the described operations herein. Additionally or alternatively, operations described herein may be performed by hardware arrangements, logic circuits, and/or electrical devices configured to perform one or more aspects of operations described herein. Examples of certain computing devices may include, but may not be limited to, one or more controllers positioned on or associated with a vehicle, engine, transmission, and/or PTO device system, personal digital assistants, laptops, personal computers, mobile phones, other handheld computing devices, wired or wireless communication devices, transducers, chips, calculators, satellites, tablet PCs, electronic books, gadgets, electronic devices, devices having artificial intelligence, networking equipment, servers, routers, and the like. Thus, while the foregoing drawings and descriptions set forth functional aspects of the disclosed systems, the descriptions herein are not limited to a particular arrangement of computer instructions, hardware devices, logic circuits, or the like for implementing operations, procedures, or methods described herein, unless explicitly stated or otherwise clear from the context. The methods and/or processes described above, and steps thereof, may be realized in hardware, instructions stored on a computer readable medium, or any combination thereof for a particular application. The hardware may include a general-purpose computer, a dedicated computing device or specific computing device, a logic circuit, a hardware arrangement configured to perform described operations, a sensor of any type, and/or an actuator of any type. Aspects of a process executed on a computing device may be realized in one or more microprocessors, microcontrollers, embedded microcontrollers, programmable digital signal processors, or other programmable device, along with internal and/or external memory. The processes may also, or instead, be embodied in an application specific integrated circuit, a programmable gate array, programmable array logic, or any other device or combination of devices that may be configured to process electronic signals. It may further be appreciated that one or more of the processes may be realized as a computer executable code capable of being executed on a machine-readable medium. Thus, in one aspect, each method described above and combinations thereof may be embodied in computer executable code that, when executing on one or more computing devices, performs the steps thereof. In another aspect, the methods may be embodied in systems that perform the steps thereof, and may be distributed across devices in a number of ways, or all of the functionality may be integrated into a dedicated, standalone device or other hardware. In another aspect, the means for performing the steps associated with the processes described above may include any of the hardware and/or computer readable instructions described above. All such permutations and combinations are intended to fall within the scope of the present disclosure. While the methods and systems described herein have been disclosed in connection with certain example embodiments shown and described in detail, various modifications and improvements thereon may become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the methods and systems described herein is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law. The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. All documents referenced herein are hereby incorporated by reference. | 193,812 |
11863009 | In some cases, the same numbers are used throughout the disclosure and the figures to reference like components and features. In some cases, numbers in the 100 series refer to features originally found inFIG.1; numbers in the 200 series refer to features originally found inFIG.2; and so on. DETAILED DESCRIPTION Some embodiments relate to peak power shaving. For example, in a data center, a battery may be used to supplement power. A stationary computing system (such as, for example, a server) can use a power supply unit (PSU) to supply power to the system. If the system has an internal energy storage device (such as, for example, a lithium ion battery) the system can perform better by utilizing power from both the PSU and the battery. The battery may be used for providing peak power to the system when the system needs more power than PSU capability, for example. If the battery is fully charged (for example, charged to 100% each time it is charged), the battery can become damaged and battery life can be limited. Keeping a battery at a fully charged state can accelerate battery degradation, can require more frequent battery replacement, and can increase total cost of ownership. However, in accordance with some embodiments, lowering the charge state (for example, lowering the battery voltage) can improve battery longevity. In some embodiments, for example, a lower battery charge termination voltage may be used in a manner in which the battery still has enough capacity to support peak load. In some embodiments, for example, after a battery ages and battery impedance increases, the charge termination voltage may be slightly increased so that the battery still maintains enough capacity to support peak load. Some embodiments relate to adjusting a battery charge termination voltage. Some embodiments relate to extending battery longevity by adjusting a battery charge termination voltage. Some embodiments relate to adjusting a battery charge termination voltage in a computer system using power from a power supply such as a power supply unit (PSU) as well as power from an internal energy storage device (for example, a rechargeable energy storage device such as, for example, a battery). In some embodiments, battery longevity and/or cycle life can be implemented by adjusting the battery charge termination voltage. In some embodiments a computing system (for example, a stationary computing system such as a server in a data center) receives power from a power supply such as a PSU. In some embodiments, the system includes a rechargeable energy storage device. In some embodiments, the rechargeable energy storage device can be an internal energy storage device such as one or more renewable energy storage device (for example, one or more battery such as one or more lithium ion battery) to help the system perform better by utilizing power from both the power supply and the energy storage device. The battery (or energy storage device) can be charged and used during times that the system needs more power than the power supply is capable of providing (for example, during peak load times). After these times are over, the battery can then be charged so that it is ready to be used again in a similar manner during other times that the system needs more power. In some embodiments, an energy storage device such as a battery or other rechargeable energy storage device can be set at an initial charge level that is at a point that just supports the system. This charge level can be increased throughout the life of the battery to continue to support the system in a manner that the battery voltage does not reach a system shutdown voltage, but nears the system shutdown voltage after being used (for example, after being used for peak load support). In some embodiments, after a rechargeable energy storage device (for example, such as a battery) used in a stationary computing system is used to help supply power to the system (for example, at an end of discharge voltage), each time the remaining voltage comes close to a system shutdown voltage (for example, within a certain tolerance level), the energy storage charge termination voltage is increased by a slight amount. The charge termination voltage can be increased a slight amount as needed (for example, as battery impedance increases). The charge termination voltage can be increased slightly in this manner several times, until the charge termination voltage is close to or at a safety threshold voltage level of the energy storage device. In some embodiments, the energy storage device is charged to a high enough charge termination voltage so that, during use of the energy storage device, the voltage of the energy storage device does not hit the system shutdown voltage. In some embodiments, the charge termination voltage is lowered to a level where the battery has enough capacity to support peak load. Whenever the voltage during peak load hits a threshold voltage level at which to increase the charge voltage, the charge termination voltage is slightly increased so that the battery maintains enough capacity to support peak load. After repeating peak load and recharge, whenever the end voltage after peak load is above a threshold voltage level at which to decrease the charge voltage (for example, due to temperature increase and/or impedance decrease), the charge termination voltage is slightly decreased. In this manner, the charge termination voltage is slightly increased whenever the voltage during peak load hits (and/or falls below) the threshold voltage level at which to increase the charge voltage, and the charge termination voltage is slightly lowered (or decreased) whenever the end voltage after peak load is above the threshold voltage level at which to decrease the charge voltage. Therefore, in accordance with some embodiments, battery longevity may be extended, less battery replacement may be required, and/or the total cost of ownership may be lowered. In some embodiments, in a data center and/or server implementation, for example, the total cost of ownership (TCO) can be lowered. This can be accomplished by lowering the load to the power station that delivers power (for example, by lowering the load to the power station that delivers power to the building) and/or made quiescent. In some embodiments, energy is not dumped into the grid and lost, but can be stored in energy storage devices such as batteries, which may be used during peak load, for example. When lulls in the system occur, the energy storage devices may be charged for later use (for example, during peak load). During peak load, the stored energy may be used without demanding additional power from the power station. FIG.1illustrates a system100in accordance with some embodiments. In some embodiments, system100is a power supply system (for example, a stationary power supply system such as a server power supply system). In some embodiments, system100includes a power supply102(for example, in some embodiments, a power supply unit102), a system load104(for example, in some embodiments, a stationary computing system load104), a battery106, a charger108, a discharger110, a controller112, and a current sensor114. In some embodiments, power supply102is a power supply unit (PSU) that can convert AC power to low-voltage regulated DC power for the internal components of a system such as a computer system. In some embodiments, battery106can be any one or more rechargeable energy storage device. In some embodiments, system100is a hybrid power boost (HPB) charging system, and charger108is a HPB charger. Charger108can provide power to charge the battery106. Discharger110can discharge battery106and provide power to system load104. In some embodiments, controller112can be a microcontroller. In some embodiments, controller112can be any type of controller, and can include a processor. In some embodiments, controller112can be an embedded controller. In some embodiments, controller112is a battery controller. In some embodiments, controller112is one or more of a microcontroller, a processor, an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), and/or a dedicated integrated circuit, etc. In some embodiments, system load104is a stationary computing system, such as, for example, a server or a desktop, among others. System load104can include a processor, a memory, one or more communication devices, etc., as well as other computing device components that make up the rest of the platform and are powered from a power supply102and can also be powered by a rechargeable battery such as battery106. In some embodiments, battery106can provide power to system load104when system load104is at a peak load. In some embodiments, battery106is a lithium-ion battery pack (and/or a lithium-ion rechargeable battery). In some embodiments, other rechargeable or non-rechargeable batteries may be used in addition to battery106or instead of battery106. In some embodiments, an energy storage (for example, such as one or more capacitor) can supplement the voltage provided by battery106to system load104. For example, such an energy storage can include one or more capacitors coupled together (for example, in series). For example, in some embodiments, such an energy storage can be implemented by one or more individual capacitors coupled together in parallel or in series. Depending on the battery configuration, resistance from the battery cells to a voltage regulator (VR) input can vary. The resistance can also change based on temperature, battery wear, and variation between components. A change from in resistance can result in a considerable difference in peak power that the system can support. Different battery configurations may be used in different embodiments. For example, in some embodiments, the system may use 2S1P (2 series 1 parallel) or 2S2P (2 series 2 parallel) battery configurations. Controller112can provide a charge enable signal to enable charger108to charge battery106using power from the power supply102(for example, when the system load104is not under peak load). Controller112can also provide a discharge enable signal to enable discharger110to discharge battery106and provide power to system load104(for example, when the system load104is under peak load). In some embodiments, controller112can monitor battery106. In some embodiments, controller112can use monitored conditions of battery106as at least partial input to making decisions such as enabling charger108, enabling discharger110, etc. In some embodiments, for example, controller112can monitor conditions such as impedance of battery106, voltage of battery106, and/or temperature of battery106, etc., among others. In some embodiments, current sensor114can sense current applied to the system load104. Controller112can provide a reference current to current sensor114, and current sensor114can provide a current monitor signal to controller112, where the current monitor signal provides an indication to controller112that corresponds to current applied to system load104(for example, in some embodiments, the current monitor signal can indicate whether the current being applied to system load104is higher than, equal to, or lower than the reference current value). In some embodiments, controller112can use monitored current applied to system load104(for example, as at least partial input in making decisions relating to enabling charger108, enabling discharger110, etc.) In some embodiments, current sensor114is a device that can detect electric current in a wire (for example, inFIG.1, can detect current in the wire leading to system load104), and can generate a signal in response to that current (for example, can generate a current monitor signal that is provided to controller112). In some embodiments, the signal generated by current sensor114can be an analog voltage or current, or can be a digital output signal (for example, a digital output signal that switches when the sensed current exceeds a certain threshold, such as a reference current threshold provided to the current sensor by the controller112). In some embodiments, system100uses power supply102to provide power to the system load104. An internal energy storage device of system100(for example, an internal energy storage device including battery106) can be used so that power is utilized by system load104using both the power supply102and the battery106under peak load conditions. For example, battery106can be kept in a state in which controller112controls charger108to keep battery106fully charged (for example, using power from the power supply102). Then, when the system load104needs more power than the power supply102can supply, in addition to power provided from the power supply, system controller112controls discharger110to provide power from the battery106to the system load104. Controller112can then later control charger108to charge battery106once the peak load condition no longer exists. FIG.2is a graph200illustrating battery voltage (V) and battery capacity (such as a remaining battery capacity by percentage). Graph200includes a battery open circuit voltage graph202and a battery voltage under load graph204. In some embodiments, graph200illustrates how battery voltage changes under peak load. For example, when a battery (for example, a battery such as battery106) is fully charged, the battery voltage may be at voltage V1illustrated at point1in graph200. When the battery is used under peak load, battery voltage changes (for example, drops) to voltage V2at point2, due to, for example, battery impedance. The voltage drop dV (delta V), or voltage change, from V1to V2can equal the current (I) times the impedance (R). That is, in some embodiments, dV=I*R. If peak load continues, battery voltage moves to the voltage at point3. After the peak load condition ends, the battery is recharged back to voltage V1at point1. Charging the battery to 100% of remaining battery capacity and then using the battery capacity during peak load conditions can be very beneficial as long as battery voltage stays above a system shutdown voltage (VmininFIG.2). However, it is noted that maintaining a battery at a fully charged state (for example, at 100% of remaining battery capacity) can accelerate battery degradation and require more frequent battery replacement. This can cause disadvantageous circumstances such as, for example, increasing the cost of ownership of the system. In some embodiments, battery longevity can be extended while supporting peak load without charging the battery to a fully charged state (for example, in a stationary computing system such as a server). In some embodiments, a charge termination voltage of the battery can be lowered to a level at which the battery has enough capacity to support peak load. After the battery ages and battery impedance increases, the charge termination voltage can be slightly increased so that the battery maintains enough capacity to support peak load. This light increase of the charge termination voltage can be implemented periodically until the battery termination voltage reaches a safety threshold. FIG.3is a graph300illustrating battery voltage (V) and battery capacity (such as a remaining battery capacity by percentage). Graph300includes a battery open circuit voltage graph302and a battery voltage under load graph304. In some embodiments, charge termination voltage is higher than battery open circuit voltage. During battery charge, for example, in accordance with some embodiments, battery voltage is equal to open circuit voltage plus IR (that is, plus current I times impedance R), according to V=VOC+IR, where V is the battery voltage during battery charge, VOCis the open circuit voltage, I is the current, and R is the impedance. In some embodiments, graph300illustrates how battery voltage changes under peak load. For example, in some embodiments, a battery (for example, a battery such as battery106) may be charged to a lower battery charge voltage (for example, to the battery voltage where its open circuit voltage is at point4inFIG.3rather than fully charged to the voltage at point1inFIG.2or dotted point1in FIG.3). When the battery is used under peak load, battery voltage changes (for example, drops) to the voltage at point5inFIG.3rather than to the voltage V2at point2inFIG.2or dotted point2inFIG.3. The change or drop from the voltage at point4to the voltage at point5is due to, for example, battery impedance. The voltage drop dV (delta V) (or voltage change) from the voltage at point4to the voltage at point5can equal the current (I) times the impedance (R). That is, in some embodiments, dV=I*R. If peak load continues, battery voltage moves to the voltage at point6. After the peak load condition ends, the battery is recharged back to the voltage where its open circuit voltage is at point4. In some embodiments, point4is a point high enough that battery voltage after supporting peak load (that is, voltage at point6) remains above the system shutdown voltage Vmin. When the battery ages, battery internal impedance increases (for example, due to a degradation in chemistry) and the voltage change (for example, voltage drop) dV during peak load (for example, the voltage drop from point4to point5and point6) increases. In this situation, the voltage at point6gets closer to system shutdown voltage Vmin. Therefore, in some embodiments, the system (for example, system100ofFIG.1using controller112) can increase the charge termination voltage from the point where open circuit voltage is at point4to the point where open circuit voltage is at point4′ to avoid hitting the system shutdown voltage Vminwhen under peak load. That is, in accordance with some embodiments, battery charge termination voltage is changed so that the corresponding open circuit voltage moves from point4to point4′ inFIG.3, for example, in order to avoid battery voltage hitting system shutdown voltage after supporting peak power. In some embodiments, as the battery ages, the system periodically repeats the increasing of the charge termination voltage from the point where open circuit voltage is4′ to various higher points on graph302until the battery charge termination voltage reaches a safety threshold (for example, at 100% remaining battery capacity, near 100% remaining battery capacity, and/or at or near point1of graph302). In some embodiments, for example, the voltage at point4inFIG.3may be 3.6 volts, and the voltage at point4′ inFIG.3corresponding to new charge termination voltage may be 3.7 volts. In some embodiments, the battery charge termination voltage may be iteratively increased by 0.1 volts each time the battery charge termination voltage needs to be increased (for example, in order to avoid hitting the system shutdown voltage Vminwhen under peak load). That is,FIG.3could include a point4″ inFIG.3along battery open circuit voltage line302corresponding to a point where battery voltage V is 3.8 volts, a point4′″ inFIG.3along battery open circuit voltage line302corresponding to a point where battery voltage V is 3.9 volts, a point4″″ inFIG.3along battery open circuit voltage line302corresponding to a point where battery voltage V is 4.0 volts, etc. These points4,4′,4″,4′″,4″″,4′″″, etc. can continue until the voltage hits the fully charged voltage level at or near point1(for example, in some embodiments, at or near 4.2 volts). Although a slight voltage change of 0.1 volts is used in some exemplary embodiments, it is noted that any other slight voltage change may be used in accordance with some embodiments (for example, 0.05 volts, 0.15 volts, or any other voltage increment). Additionally, in some embodiments, the slight voltage increase can be a dynamic increase rather than an increase of a set amount such as 0.1 volts. In some embodiments, for example, the battery impedance may be considered. For example, in some embodiments, if the battery impedance increases by a certain percentage (for example, increases by 10%), an amount of additional voltage drop (voltage change) may be calculated for considering how much to increase the battery charge termination voltage. That is, in some embodiments, the battery charge termination voltage can be dynamically changed by sensing the impedance (for example, in some embodiments, using a sensor to sense the impedance and provide the sensed impedance to a controller such as controller112inFIG.1to dynamically change the termination voltage based on the sensed impedance). This impedance can be monitored using a controller or microcontroller such as controller112throughout the life of the battery. In some embodiments, the controller or microcontroller can increase the battery charge termination voltage a certain amount that corresponds to the sensed amount (and/or sensed percentage) of increase of the impedance. In some embodiments, the controller (for example, controller112) can adjust the charging circuit (for example, charger108) a dynamic amount to elevate the charge voltage of the battery (for example, battery106) based on the amount of increase of the impedance. In some embodiments, in charging (for example, in charging the battery from point6to point4or to point4′ inFIG.3, or to other battery charge termination voltages, for example) constant current charging may be implemented. In some embodiments, in charging (for example, in charging the battery from point6to point4or to point4′ inFIG.3, or to other battery charge termination voltages, for example) constant current charging (constant current or CC) followed by constant voltage charging (constant current constant voltage, or CCCV) may be implemented. In some embodiments, in charging (for example, in charging the battery from point6to point4or to point4′ inFIG.3, or to other battery charge termination voltages, for example) constant current charging followed by a rest time for cooling (CC plus rest time) may be implemented. In some embodiments, in charging (for example, in charging the battery from point6to point4or to point4′ inFIG.3, or to other battery charge termination voltages, for example) constant current charging followed by constant voltage charging followed by a rest time for cooling (CCCV plus rest time) may be implemented. In some embodiments, for example, rest time can be dynamically added based on a monitoring of battery temperature (for example, monitoring of battery temperature by a controller such as controller112). That is, rest time can be dynamically added during charging to allow the battery to cool down. In some embodiments, the lower the battery charge level (battery charge termination voltage and/or remaining battery capacity), the better the expected battery longevity. This is because the lower charge level can correspond to lower battery level, which provides less damage to the battery. For example, in some embodiments, using a battery charge termination voltage at a point of around 60% remaining battery charge capacity rather than at a point of around 100% remaining battery charge capacity can provide better battery longevity. In some embodiments, a battery charge termination voltage is used so that a battery voltage point after supporting peak load (for example, a voltage at point6) remains close to but above the system shutdown voltage (for example, system shutdown voltage Vmin). In some embodiments, battery voltage is maintained at a voltage that is as low as possible while keeping the voltage level high enough to support peak load and stay above a system shutdown voltage during peak load support. In this manner, battery longevity can be extended while maintaining an ability to support peak load using the battery. In some embodiments, peak load may last several seconds. In some embodiments, peak load may last tens of seconds. In some embodiments, peak load may last a length of time from several seconds to tens of seconds. In other embodiments, peak load may last different lengths of time. In some embodiments, the battery is discharged quickly (for example, during peak load), but in some embodiments the battery is not discharged as quickly. In some embodiments, battery impedance may depend on one or more factors, including one or more of battery temperature, degradation, load, state of charge, duration, and/or other factors. In some embodiments, when the target charge voltage is calculated based on the impedance (and/or the increase in impedance), the impedance calculation can consider one or more of these factors (for example, one or more of battery temperature, degradation, load, state of charge, duration, and/or other factors). In some embodiments, impedance may be sensed by sensing the voltage change (for example, the voltage drop) and/or sensing the current to the load (for example, using controller112to sense the voltage change and/or the current to the load using current sensor114) and then calculating the impedance based on these factors. That is, in some embodiments, the impedance may be sensed directly, and in some embodiments, the impedance may be calculated by other sensed factors (for example, sensed voltage change and/or sensed current). In some embodiments, techniques described herein can be implemented in a system, memory space of a system, in a controller, in a memory space of a controller in a data center system, and/or in a battery pack, for example. In some embodiments, techniques described herein can be implemented in a remote system that is remote from the system load. Such a remote system can send charge voltage control to the data center to charge the battery accordingly. The remote system could be in a host that is on-site, or in any remote location. In some embodiments, techniques described herein can be implemented based on information from a remote integrated circuit (IC), a battery pack and/or from an IC of a battery pack (for example, in a fuel gauging IC). For example, in some embodiments, when impedance is calculated, the information used to calculate the impedance (for example, voltage change information and/or current information) can be provided from a remote IC, a battery pack and/or from an IC of a battery pack (for example, in a fuel gauging IC). In some embodiments, techniques described herein (and/or implemented by a controller described herein) may be implemented by a firmware embedded solution, an FPGA, a DSP, a discrete ASIC, and/or a processor, etc. In some embodiments, a system (for example, system100and/or system load104) can be one or more of a computing system, a stationary system, a data center system, a server, a car, a robot, a medical device, and/or a system supporting peak energy use of one or more building such as an office building, an industrial building, a home, an apartment building, etc. In some embodiments, the system can be any system with spare battery capacity (for example, battery capacity that is temporarily spare). In some embodiments, impedance can include an ohmic portion (for example, impedance for a short duration) and/or a polarization portion (for example, impedance for a long duration). Implementations using one battery are shown and described herein in some embodiments. However, in some embodiments, a battery as used herein can include one battery, multiple batteries connected in parallel, multiple batteries connected in series, one or more 1S battery, one or more 2S battery, one or more other multi-S battery, etc. In some embodiments, a battery as used herein can be a lithium ion battery with LiCoO2cathode and graphic anode. In some embodiments, a battery as used herein is applicable to other chemistries. Some embodiments relate to battery charge termination voltage adjustment. In some embodiments, a first operation includes lowering battery charge termination voltage to a level where the battery has enough capacity to support peak load. In some embodiments, a second operation includes, after the battery ages and/or battery impedance increases, slightly increasing the battery charge termination voltage so that the battery keeps enough capacity to support peak load (for example, in view of the aging battery and/or battery impedance increase). In some embodiments, a third operation includes repeating (for example, periodically repeating) the second operation of slightly increasing the battery charge termination voltage (for example, until the battery charge termination voltage reaches a safety threshold such as, for example, a safety threshold where the remaining battery capacity is approximately 100%). Some embodiments relate to battery charge termination voltage adjustment. In some embodiments, a first operation includes lowering battery charge termination voltage to a level where the battery has enough capacity to support peak load, such as, for example, point4inFIG.3. It is noted that point4inFIG.3can be the point where battery voltage after supporting peak load (for example, the voltage at point6inFIG.3) is above a system shutdown voltage (for example, is above system shutdown voltage VmininFIG.3). In some embodiments, a second operation includes, after the battery ages and/or battery impedance increases (for example, the voltage change or voltage drop dV from point4to point5and point6ofFIG.3nears the system shutdown voltage VminofFIG.3), slightly increasing the battery charge termination voltage (for example, from the voltage where open circuit voltage is at point4to the voltage where open circuit voltage is at point4′ ofFIG.3) so that the battery keeps enough capacity to support peak load (for example, to avoid hitting the system shutdown voltage VminofFIG.3under peak load). In some embodiments, a third operation includes repeating (for example, periodically repeating) the second operation of slightly increasing the battery charge termination voltage (for example, until the battery charge termination voltage reaches a safety threshold such as, for example, a safety threshold where the remaining battery capacity is approximately 100% such as at point1ofFIG.3). FIG.4illustrates a flow diagram400that can relate to battery charge termination voltage adjustment according to some embodiments. The operations of flow diagram400may be performed by a control unit or a controller (for example, such as controller112and/or other units). In some embodiments, the control unit or controller implementing flow400may include one or more processors, monitoring logic, control logic, software, firmware, agents, controllers, and/or other modules. In some embodiments, flow400can include additional operations and/or does not include all operations illustrated and/or described herein. At operation402, a battery is charged to a charge termination voltage where the battery still has the capacity to support peak load. In some embodiments, for example, operation402can charge the battery to a battery charge termination voltage level that just supports peak load of the system in a manner that the voltage comes close to the system shutdown voltage after supporting peak load. In some embodiments, at the first time through operation402, the battery is charged to a low level battery charge termination voltage where the battery still has the capacity to support peak load. In some embodiments, for example, at each iteration, operation402can charge the battery to an initial battery charge termination voltage level that just supports peak load of the system in a manner that the voltage comes close to the system shutdown voltage after supporting peak load. In some embodiments, in some later iterations of operation402, if applicable, after peak load support, operation402can charge the battery to a slightly increased battery charge termination voltage that is increased from the initially low level. In some embodiments, for example, operation402can charge the battery to an initial low battery charge termination voltage such as a voltage at which a remaining battery capacity is around 60%, per example. In some embodiments, for example, operation402can charge the battery to an initial low voltage such as the voltage at point4inFIG.3, for example. In some embodiments, after peak load support, operation402can charge the battery to other slightly increased voltages such as the voltage at point4′ inFIG.3, and other slightly increased voltages after point4′ inFIG.3, for example. In some embodiments, after an end of battery discharge voltage after supporting peak load, when the voltage comes close to the system shutdown voltage, battery charge termination voltage is slightly increased so that the battery discharge voltage after subsequently supporting peak load will still remain above the system shutdown voltage. At operation404, after the battery has been charged to the battery charge termination voltage where the battery still has capacity to support peak load, the battery may be used for peak load support. At operation406, after the battery has been used to support peak load, a determination may be made as to whether the battery impedance (for example, the internal battery impedance) has increased a certain amount that is enough to trigger an increase in the battery charge termination voltage. Since an increase in battery impedance will create a higher voltage change (for example, voltage drop) of the battery during use of the battery (for example, during peak load support), the battery may come too close to system shutdown voltage during use, and an increase in battery charge termination voltage may be necessary to ensure that the voltage does not hit the system shutdown voltage during peak load support, for example. If the battery impedance has not increased the determined amount at operation406, flow returns to operation402to charge the battery to the battery same charge termination voltage (for example, after peak load has been supported, or the voltage has otherwise changed or dropped below the proper level). If the battery impedance has increased that amount at operation406, flow can move to operation408, where the battery charge termination voltage is slightly increased (for example, by a small amount such as around 0.1 volts or so, for example, and/or is slightly increased from point4inFIG.3to point4′ inFIG.3, or from point4′ inFIG.3to a point on line302with a corresponding voltage that is slightly higher than the voltage corresponding to that at point4′, for example). At operation410, after the battery charge termination voltage has been slightly increased at operation408, a determination is made as to whether the battery charge termination voltage has reached a safety threshold (for example, has reached a 100% battery charge level, and/or has reached a voltage corresponding to the voltage at point1inFIG.2or the voltage at point1inFIG.3). If the battery charge termination voltage has not reached the safety voltage at operation410, flow returns to operation402, where the battery is charged to the current battery charge termination voltage. If the battery charge termination voltage has reached the safety voltage at operation410, flow moves to operation412, where a battery replace notification is provided to indicate that the battery should be changed, for example. At operation414the battery is charged to a battery charge termination voltage equal to the safety threshold voltage. Then, at operation416, after the battery has been charged to the battery charge termination voltage equal to the safety threshold voltage, the battery may be used for peak load support. Then flow returns to operation412. In this manner, the battery replace notification can be provided at412, the battery can be charged to the safety threshold voltage at414, and the battery can be used for peak load support at416until the battery is replaced. Once the battery is replaced, flow400can begin again at an initial operation of operation402(for example, where the new battery is charged at an initial low level battery charge termination voltage where the battery still has capacity to support peak load. In some embodiments, when the battery charge termination voltage reaches the safety threshold at operation410, the battery may be close to a dead battery condition. Therefore, in some embodiments, the system (for example, system100and/or controller112) can communicate with a management system (for example, with a data center management system). In some embodiments, the management system can send a robot or a human to come out and to replace the battery (for example, to replace battery106). It is noted that many other implementations of flow400may be made in accordance with some embodiments. For example, in some embodiments, a battery replace notification may be made before the charge termination voltage reaches the safety threshold. For example, in some embodiments, the battery replace notification may be made at a certain charge termination voltage less than the safety threshold (for example, 0.1 volts lower than the safety threshold, or at some other battery charge termination voltage level). In some embodiments, for example, instead of determining whether battery impedance has increased a certain amount at operation406, other operations may be performed. For example, an age of the battery determination may be used at operation406in accordance with some embodiments. In general, the lower the charge state of a battery (and/or the lower the battery voltage), the better the expected longevity of the battery. In some embodiments (for example, in some embodiments as described above), a system starts with a lower charge termination voltage where the battery still has enough capacity to support peak load. After the battery ages and battery impedance increases, the charge termination voltage may be slightly increased so that the battery maintains enough capacity to support peak load. FIG.5is a graph500illustrating battery voltage (V volts) and battery temperature (degrees Celsius) over time. Graph500includes a battery voltage under load graph502and a battery temperature graph504. In some embodiments,FIG.5illustrates a case of repeated peak load (for example, with repeated peak load at 4 A for 20 seconds, and then battery recharge). It is noted thatFIG.5is shown as an example, and many more charges and discharges may occur than as shown inFIG.5(that is, the battery under load graph502may have a much higher frequency than shown inFIG.5). In some embodiments,FIG.5illustrates a starting battery charge termination voltage of 3.5 volts rather than a standard starting battery charge termination voltage of 4.2 volts, for example. Dotted line506illustrates a threshold voltage at which to increase the battery charge voltage (for example, illustrated as 2.5 volts inFIG.5). When the battery voltage during peak load hits the threshold voltage506at which to increase the battery charge voltage, the charge termination voltage may be increased (for example, increased by 0.1 volts from 3.5 volts to 3.6 volts, increased by 0.3 volts from 3.5 volts to 3.8 volts, increased in 0.1 volt increments from 3.5 volts to 3.8 volts each time that the battery charge voltage reaches the threshold voltage506, etc., among other increases and/or increase increments in accordance with some embodiments). As illustrated inFIG.5, after implementing peak power shaving, after repeated charge and discharge of the battery, battery temperature can increase. As the battery temperature increases, the internal impedance of the battery may decrease. Over time, since the battery temperature may increase and the internal impedance of the battery may decrease, even after repeated 4 A for 20 seconds discharge, the battery voltage after discharge may stay at a higher level (for example, inFIG.5at a higher voltage of around 3.1V or 3.2V after battery discharge), and the voltage may not again decrease to the threshold level506. AlthoughFIG.5illustrates an embodiment in which the charge termination voltage is successfully lowered (for example, from 4.2V to 3.8V) while supporting peak load, a gap508between the threshold voltage506at which to increase the charge voltage and an end discharge voltage of the battery voltage under load502that occurs after peak load can become too large over time (for example, as illustrated by gap508inFIG.5). This may occur due to repeated peak load and recharge generate joule heat, increased battery temperature, and/or decreased battery impedance (for example, occurring as a result of increased ionic mobility at higher temperature). When a large gap508occurs, charge termination may be increased to a level that is unnecessarily high, which can accelerate battery degradation. Therefore, in accordance with some embodiments, battery longevity may be extended more efficiently in a system that considers, for example, battery temperature and/or battery impedance. In some embodiments, for example, a threshold voltage at which to decrease battery charge voltage may be used to lower charge termination voltage. For example, in some embodiments, after repeating peak load and battery recharge, if the end battery voltage after peak load is above a threshold voltage at which to decrease the battery charge voltage (for example, because of temperature increase and/or impedance decrease), the battery charge termination voltage may be lowered (for example, may be slightly lowered). In accordance with some embodiments, a battery charge termination voltage may be lowered to and/or set at a level where the battery has enough capacity to support peak load, but is at a level less than a full charge voltage (for example, a lower battery charge termination voltage of 3.5V may be used). When the voltage during peak load reaches a lower threshold level (for example, a threshold voltage at which to increase the charge voltage), the charge termination voltage may be slightly increased (for example, increased by 0.1V) so that the battery maintains enough capacity to support peak load. For example, in some embodiments, a lower threshold voltage level below which the battery charge voltage is to be increased may be 2.5V. After repeating peak load and recharge, if the end voltage after peak load is above an upper threshold level (for example, a threshold level at which to decrease the charge voltage) that occurs, for example, due to battery temperature increase and/or battery impedance decrease, the battery charge termination voltage may be slightly lowered (for example, lowered by 0.05V). For example, in some embodiments, an upper threshold voltage level above which the battery charge voltage is to be decreased may be 2.8V. The battery charge termination voltage may be slightly increased each time the voltage during peak load falls below the lower threshold level (for example, a 2.5V lower threshold), and may be slightly decreased each time the end voltage after peak load is above the upper threshold level (for example, a 2.8V upper threshold), until the battery charge termination voltage reaches a safety threshold level (for example, at 100% remaining battery capacity, near 100% remaining battery capacity, at or near a safety voltage threshold of 4.2V, and/or at or near point1of graph302inFIG.3). FIG.6is a graph600illustrating battery voltage (V volts) and battery temperature (degrees Celsius) over time. Graph600includes a battery voltage under load graph602and a battery temperature graph604. Graph600also illustrates a lower threshold voltage606(for example, 2.5V), an upper threshold voltage610(for example, 2.8V), and an initial charge termination voltage612(for example, 3.5V). As illustrated inFIG.6, at the beginning, when the battery voltage hits the lower threshold voltage606, the charge voltage is increased a slight amount (for example, increased by 0.1V in some embodiments). As illustrated inFIG.6, the charge voltage is increased from the initial charge voltage612by 0.1V each time the lower threshold voltage is hit (for example, each time the voltage hits or falls below the lower threshold voltage606). However, as the battery temperature604increases (and/or, for example, as the battery impedance decreases), when the end voltage after peak power load is either at the upper threshold voltage610or ends above the threshold voltage610, for example, the charge voltage is slightly decreased (for example, as illustrated inFIG.6, may be decreased by 0.05V). The voltage at the end of each peak power load may be compared to the threshold voltage610. In this manner, in response to the comparison of the voltage at the end of peak power with the threshold voltage610, a determination may be made to decrease the battery charge voltage, and battery life may be improved as a result. In some embodiments,FIG.6illustrates a case of repeated peak load (for example, with repeated peak load with 4 A for 20 seconds, and then battery recharge). In some embodiments,FIG.6illustrates a starting battery charge termination voltage612of 3.5 volts rather than a standard starting battery charge termination voltage of 4.2 volts, for example. Dotted line606illustrates a threshold voltage at which to increase the battery charge voltage (for example, illustrated as 2.5 volts inFIG.6). Dotted line610illustrates a threshold voltage at which to decrease the battery charge voltage (for example, illustrated as 2.8 volts inFIG.6). When the battery voltage during peak load hits the lower threshold voltage606at which to increase the battery charge voltage, the charge termination voltage may be increased (for example, increased by 0.1 volts from 3.5 volts to 3.6 volts, increased by 0.3 volts from 3.5 volts to 3.8 volts, increased in 0.1 volt increments from 3.5 volts to 3.8 volts each time that the battery charge voltage reaches the threshold voltage606, etc., among other increases and/or increase increments in accordance with some embodiments). When the end battery voltage after peak load is above the higher threshold voltage610at which to decrease the battery charge voltage, the charge termination voltage may be decreased (for example, decreased by 0.05 volts from 3.8 volts to 3.75 volts, decreased by 0.05 volts from 3.75 volts to 3.7 volts, and/or decreased by 0.05 volts each time that the end battery voltage after peak load remains above the upper threshold voltage610, etc., among other decreases and/or decrease increments in accordance with some embodiments). As illustrated inFIG.6, in some embodiments, charge termination voltage starts at an initial charge termination voltage612. The initial charge termination voltage612may be lower than a traditional full charge voltage in some embodiments. For example, initial charge termination voltage612may be 3.5V rather than a traditional full charge voltage of 4.2V in accordance with some embodiments. When voltage during peak load reaches a lower voltage threshold606at which to increase the charge voltage (for example, a lower threshold voltage of 2.5V), the charge termination voltage may be increased so that the battery maintains enough capacity to support peak load (for example, increased by 0.1V). As illustrated inFIG.6, charge termination voltage may increase from 3.5V to 3.8V, increasing by 0.1V each time voltage during peak load reaches the lower voltage threshold606, for example. After repeating peak load and recharge, if the end voltage after peak load is above the upper voltage threshold610(for example, a threshold voltage at which to decrease the charge voltage, and/or an upper threshold voltage of 2.8V), which may occur, for example, due to a battery temperature increase and/or a battery impedance decrease, the charge termination voltage may be slightly decreased (for example, slightly decreased by 0.05V).FIG.6illustrates an example in which charge termination voltage may be decreased in 0.05V decrements from 3.8V to 3.55V as end voltage after peak load stays above the upper voltage threshold610. That is, each time end voltage after peak load stays above the upper voltage threshold610, the charge termination voltage is decreased by 0.05V in the example illustrated inFIG.6. In some embodiments, the battery charge termination voltage is then increased each time the voltage during peak load is low enough to reach the lower threshold voltage606, and the battery charge termination voltage is then decreased each time the end voltage after peak load stays above the upper threshold voltage610, until the battery charge termination voltage reaches a battery safety voltage (for example, at 100% remaining battery capacity, near 100% remaining battery capacity, at or near a safety voltage threshold of 4.2V, and/or at or near point1of graph302inFIG.3). It is noted thatFIG.6illustrates an example in which, after the end voltage after peak load is at or above the upper threshold610, the end voltage after peak load does not again reach the lower threshold606. However, it is noted that the end voltage after peak load may reach the lower threshold606again in some embodiments. For example, in some embodiments, if the battery temperature604decreases again (for example, after a long period of relaxation and/or non-use of the battery), the lower threshold may be again reached and the charge termination voltage may then again be slightly increased (for example, by 0.1V in some embodiments). In some embodiments, the charge termination voltage may be increased in such an embodiment if the voltage602reaches the lower voltage threshold606(for example, is at or below threshold voltage606). In some embodiments, the charge termination voltage may again be slightly increased (for example, by 0.1V in some embodiments) based on a sensed decrease in the battery temperature604. Although the battery termination voltage has been described and illustrated herein as being changed in response to a comparison of the end voltage after peak load with a voltage threshold, the battery termination voltage may be changed in accordance with some embodiments in response to a change in other factors. For example, in some embodiments, battery termination voltage may be changed in response to a change in battery temperature and/or in response to a change in battery impedance (for example, a change in internal battery impedance). In some embodiments, for example, the battery charge termination voltage may be slightly increased in response to a decrease in battery temperature and/or in in response to an increase in battery impedance, and/or the battery charge termination voltage may be slightly decreased in response to an increase in battery temperature and/or in response to a decrease in battery impedance. FIG.7is a graph700illustrating battery voltage (V volts) and battery temperature (degrees Celsius) over time. Graph700includes a battery voltage under load graph702and a battery temperature graph704. Graph700also illustrates a lower threshold voltage706(for example, 2.5V), an upper threshold voltage710(for example, 2.8V), and an initial charge termination voltage712(for example, 3.5V). In some embodiments,FIG.7illustrates a case of repeated peak load (for example, with repeated peak load with 4 A for 20 seconds, and then battery recharge). In some embodiments,FIG.7illustrates a starting battery charge termination voltage712of 3.5 volts rather than a standard starting battery charge termination voltage of 4.2 volts, for example. Dotted line706illustrates a threshold voltage at which to increase the battery charge voltage (for example, illustrated as 2.5 volts inFIG.7). Dotted line710illustrates a threshold voltage at which to decrease the battery charge voltage (for example, illustrated as 2.8 volts inFIG.7). When the battery voltage during peak load hits the lower threshold voltage706at which to increase the battery charge voltage, the charge termination voltage may be increased (for example, increased by 0.1 volts from 3.5 volts to 3.6 volts, increased by 0.3 volts from 3.5 volts to 3.8 volts, increased in 0.1 volt increments from 3.5 volts to 3.8 volts each time that the battery charge voltage reaches the threshold voltage706, etc., among other increases and/or increase increments in accordance with some embodiments). When the end battery voltage after peak load is above the higher threshold voltage710at which to decrease the battery charge voltage, the charge termination voltage may be decreased (for example, decreased by 0.05 volts from 3.6 volts to 3.55 volts, decreased by 0.05 volts from 3.55 volts to 3.5 volts, decreased by 0.05 volts from 3.5 volts to 3.45 volts, and/or decreased by 0.05 volts each time that the end battery voltage after peak load remains above the upper threshold voltage710, etc., among other decreases and/or decrease increments in accordance with some embodiments). As illustrated inFIG.7, in some embodiments, charge termination voltage starts at an initial charge termination voltage712. The initial charge termination voltage712may be lower than a traditional full charge voltage in some embodiments. For example, initial charge termination voltage712may be 3.5V rather than a traditional full charge voltage of 4.2V in accordance with some embodiments. When voltage during peak load reaches a lower voltage threshold706at which to increase the charge voltage (for example, a lower threshold voltage of 2.5V), the charge termination voltage may be increased so that the battery maintains enough capacity to support peak load (for example, increased by 0.1V). After repeating peak load and recharge, if the end voltage after peak load is above the upper voltage threshold710(for example, a threshold voltage at which to decrease the charge voltage, and/or an upper threshold voltage of 2.8V), which may occur, for example, due to a battery temperature increase and/or a battery impedance decrease, the charge termination voltage may be slightly decreased (for example, slightly decreased by 0.05V). In some embodiments, when battery temperature starts decreasing, battery impedance may start increasing. In some embodiments illustrated inFIG.7, for example, charge termination voltage may be increased when battery temperature decreases, and/or battery termination voltage may be increased when battery impedance decreases. This increase in charge termination voltage may be implemented, for example, to support peak load. In some embodiments, battery charge termination voltage may be calculated by battery impedance, which is a function of battery temperature. In some embodiments, future battery temperature by thermal inertia may also be considered. In some embodiments, the battery charge termination voltage is then increased each time the voltage during peak load is low enough to reach the lower threshold voltage706, and/or the battery charge termination voltage is then increased each time the battery temperature decreases, and/or the battery charge termination voltage is then increased each time the battery impedance increases, and/or the battery charge termination voltage is then adjusted based on thermal inertia (for example, the battery charge termination voltage is increased based on an increase in thermal inertia), and/or the battery charge termination voltage is then decreased each time the end voltage after peak load stays above the upper threshold voltage710, until the battery charge termination voltage reaches a battery safety voltage (for example, at 100% remaining battery capacity, near 100% remaining battery capacity, at or near a safety voltage threshold of 4.2V, and/or at or near point1of graph302inFIG.3). In accordance with some embodiments (for example, in any embodiments illustrated and/or described herein, including examples illustrated in reference toFIGS.5,6, and7), the lower the charge level (for example, 0% of safety threshold voltage instead of 100%), the better the expected battery longevity. This is due to lower charge level corresponding to lower battery voltage, which creates less damage to the battery, for example. In some embodiments, battery voltage is maintained as low as possible while maintaining enough voltage to support peak load. This is implemented even after battery temperature and/or battery impedance changes, and extends battery longevity. FIG.8illustrates a flow diagram800in accordance with some embodiments. In some embodiments,FIG.8illustrates battery charge termination voltage adjustment in accordance with some embodiments. In some embodiments, flow800may be implemented by any of system100, system900, and/or system1000, and/or any portion of those systems, for example. In some embodiments, flow800may be implemented by processor1102performing instructions1106. The operations of flow diagram800may be performed by a control unit or a controller (for example, such as controller112, controller912, processor1002, processor1102, and/or other units). In some embodiments, the control unit or controller implementing flow800may include one or more processors, monitoring logic, control logic, software, firmware, agents, controllers, and/or other modules. In some embodiments, flow800can include additional operations and/or does not include all operations illustrated and/or described herein. At802the battery is charged to a battery termination voltage at which the battery still has capacity to support peak load (for example, to 3.5V in some embodiments). The battery is used for peak load at804. At806a determination is made as to whether the battery voltage during peak load had hit (for example, is at or below) a threshold to increase the battery charge voltage (for, example, is at or below a lower threshold voltage at which the battery charge voltage is to be increased, and/or is at or below a threshold voltage of 2.5V). If the battery voltage has hit the threshold at806, the battery charge termination voltage is increased (for, example, is slightly increased, and/or is increased by 0.1V) at808. If the battery voltage has not hit the threshold at806, a determination is made at810as to whether an end voltage after peak load is above (for example, is at or above) a threshold voltage at which to decrease the battery charge voltage (for example, the end voltage after peak load is at or above an upper threshold voltage at which the battery charge voltage is to be decreased, and/or is at or above 2.8V). If the end voltage after peak load is above (for example, at or above) the threshold to decrease the battery charge voltage at810, the battery charge termination voltage is decreased (for example, is slightly decreased, and/or is decreased by 0.05V) at812. If the end voltage after peak load is not above (for example, is not at or above) the threshold to decrease the battery charge voltage at810, a determination is made at814as to whether battery temperature changes have occurred (and/or in some embodiments, as to whether battery impedance changes have occurred, and/or as to whether thermal inertia changes have occurred). If battery changes (and/or battery impedance changes, and/or thermal inertia changes) have occurred at814, the battery charge termination voltage is adjusted at816(for example, the battery charge termination voltage is adjusted considering battery impedance change, battery temperature change, etc.) If battery changes (and/or battery impedance changes, and/or thermal inertia changes) have not occurred at814, a determination is made at818as to whether the battery charge termination voltage has reached a safety threshold voltage level (for example, a safety threshold voltage level of 4.2V). If the battery charge termination voltage has not reached a safety threshold voltage level at818, flow returns to802. If the battery charge termination voltage has reached a safety threshold voltage level at818, a battery replacement notification is made at820. The battery is charged to the safety threshold voltage level at822, and the battery is used for peak load support at824. After peak load support, a determination is made at826as to whether the battery has been replaced. If the battery has been replaced at826, flow returns to802. If the battery has not been replaced at826, flow returns to820. In accordance with some embodiments, the voltage threshold at which to decrease battery charge voltage (for example, an upper threshold, and/or a 2.8V threshold) may be higher than the voltage threshold at which to increase the battery charge voltage (for example, a lower threshold, and/or a 2.5V threshold). However, other voltages and/or relative voltages for the threshold at which to decrease battery charge voltage and/or the threshold at which to increase battery charge voltage may be implemented in accordance with some embodiments. In some embodiments, a charge voltage increase of 0.1V and a charge voltage decrease of 0.05V has been used in accordance with some examples. However, other voltage increments for the charge voltage increase and/or for the charge voltage decrease may be used in accordance with some embodiments. In some embodiments, voltage decrease may be calculated based on the gap between end battery voltage (for example, end battery voltage after peak load) and the threshold voltage at which to decrease the battery charge voltage. In some embodiments, battery charge termination voltage may be calculated based on battery impedance. For example, battery charge termination voltage may be calculated based on battery impedance that is a function of present battery temperature, and/or is a function of battery charge current and/or battery discharge current, and/or is a function of a difference between battery temperature and ambient temperature, which leads to future battery temperature. In some embodiments, the charge and/or discharge current may be actively limited. This can result in asymmetric operation that can be used to manage the temperature of the battery. For example, more discharge may be allowed earlier in time to achieve a steady state temperature, or may allow higher charge to temporarily cool the battery. In some embodiments, the charge and/or discharge current may be actively limited, and the voltage thresholds may be limited and/or adjusted in order to actively manage the battery impedance, and/or to improve battery longevity or lower costs. In some embodiments, future battery lifespan may be predicted. In some embodiments, a history of battery impedance and/or battery temperature may be used to manage present and future current and voltage thresholds. For example, in some embodiments, one or more voltage thresholds may be dynamically changed based on current measurements (for example, based on current measurements of battery temperature and/or of battery impedance), and/or may be dynamically changed based on historical measurements (for example, based on historical measurements of battery temperature and/or of battery impedance). In some embodiments, one or more voltage thresholds may be dynamically changed based on future predictions (for example, based on future predictions of battery temperature and/or future predictions of battery impedance). For example, in accordance with some embodiments, voltage thresholds such as voltage values506,606,610,612,706,710, and/or712may be adjusted (for example, may be dynamically adjusted) based on current and/or historical and/or predicted future information (for example, based on current and/or historical and/or predicted future information such as current and/or historical and/or predicted future battery temperature information and/or such as current and/or historical and/or predicted future battery impedance information). Such adjustments may be made to help increase battery lifespan. In some embodiments, charging currents may be adjusted. For example, current capabilities may be reduced based on system constraints (for example, based on provided system constraints). For example, if an owner of the system is interested in having the battery obtain a particular life (such as, for example, five years of life in exchange for less capability), currents and/or voltage thresholds may be adjusted accordingly. For example, if the device is labelled as a 20 A device, but the system begins bumping into thresholds and battery temperatures and/or impedances are heading in the wrong direction, a system manager may be used to reduce currents (for example, lower than 20 A) and extend the life of the battery. This may be dynamically implemented (for example, using a tuner knob type of implementation). The system may be biased (tuned) more toward performance or longevity (for example, higher performance or lower total cost of ownership), for example, by the owner of the system according to particular needs, and may be changed over time. In some embodiments, the future lifespan of one or more batteries may be predicted. Accurately predicting battery lifespan can be very advantageous for the seller of the battery, the original equipment manufacturer, and the customer. Balancing between performance and lifespan can be of great benefit. In some embodiments, when temperature plateaus, a battery can have a very long lifespan using the techniques described herein. Therefore, in some embodiments, if greater performance is desired, more current may be pulled in and out of the battery, and more performance may be obtained from the battery during the life of the product while still maintaining an increased lifespan. In some embodiments, if battery packs implemented in accordance with techniques described herein are used in parallel, batteries may be allowed to warm up or cool down at a specific rate to implement higher performance based on the characteristics of the workload of the batteries. A system user may then be able to pull out one of the battery packs and save money and run the remaining batteries at higher performance in accordance with some embodiments. In some embodiments, techniques illustrated and/or described herein may be implemented in a memory space of the system. In some embodiments, techniques illustrated and/or described herein may be implemented in a battery pack. In some embodiments, techniques illustrated and/or described herein may be implemented in a remote system that controls a system with the battery, including any of the systems described and/or illustrated herein. In some embodiments, techniques illustrated and/or described herein may be based on information from an integrated circuit (IC) in a battery pack (for example, from a fuel gauging IC). In some embodiments, techniques illustrated and/or described herein may be implemented in hardware, software, in firmware, and/or in any combination of hardware, software, and/or firmware. In some embodiments, techniques illustrated and/or described herein may be implemented in one or more field programmable gate array (FPGA) device, an application specific integrated circuit (ASIC), etc., and/or in other devices. In some embodiments, systems illustrated and/or illustrated and/or described herein may be stationary systems. In some embodiments, systems illustrated and/or described herein may be portable systems. In some embodiments, systems illustrated and/or described herein may be included in a car, a robot, a medical device, and/or other systems. In some embodiments, systems illustrated and/or described herein may be included in any system that has an energy storage device and/or a battery. In some embodiments, systems illustrated and/or described herein may support peak energy use of a building (such as a residential building, a commercial building, an industrial building, an office building, etc.) As used herein, impedance may include an ohmic portion. Additionally, impedance as used herein may include a polarization portion. Some embodiments relate to use with a 1S battery. Some embodiments relate to a multi-S battery (for example, a 2S battery, a 4S battery, etc.) In some embodiments, a battery may be a lithium ion battery (for example, a Li-ion battery with LiCoO2cathode and graphite anode). In some embodiments, a battery may be a battery with other chemistries. In some embodiments, a voltage window between battery charge termination voltage and end voltage of peak load may be chosen. This voltage window may be chosen to maintain the charge termination voltage as low as possible. In some embodiments, the window may be chosen to maintain charge termination voltage as low as possible considering joule heat battery impedance (which may depend on charge state and/or heat by chemical reaction during charge and/or discharge). FIG.9illustrates a system900in accordance with some embodiments. In some embodiments, system900includes a battery906, a controller912, and one or more sensor914. In some embodiments, one or more sensor914includes one or more current sensor914. In some embodiments, one or more sensor914includes one or more voltage sensor914. In some embodiments, one or more sensor914includes one or more temperature sensor914. In some embodiments, one or more sensor914includes a group of one or more sensors that can include one or more voltage sensors, and/or one or more current sensors, and/or one or more temperature sensors. In some embodiments, one or more sensors914can include one or more voltage/current/temperature sensors. In some embodiments, battery906is the same as or similar to battery106. In some embodiments, controller912is the same as or similar to controller112. In some embodiments, sensor(s)914is one or more sensor that is the same as or similar to current sensor114. In some embodiments, controller912is a battery controller. In some embodiments, controller912is one or more of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), a processor, etc. including some of all of the functional blocks inFIG.9In some embodiments, all or part of controller912is implemented in software as stored on a memory (for example, memory922) and executed by, for example, a processor or microcontroller (for example, microcontroller/processor920). In some embodiments, controller912can be, for example, a control integrated circuit (IC). In some embodiments, controller912can be part of a power management integrated circuit (PMIC). In some embodiments, controller912can be part of a fuel gauge. In some embodiments, controller912can be part of a battery management system. Controller912interfaces with battery906using an interface940. Interface940can include a physical interface for supplying power and ground. In some embodiments, interface940includes a data interface. Controller912interfaces with sensor(s)914using an interface950. Interface950can include a physical interface for supplying power and ground. In some embodiments, interface950includes a data interface. In some embodiments, interface950can include one or more interfaces. In some embodiments, controller912includes a processor or microcontroller920, a memory922, battery charger924, battery discharger926, and/or energy storage charge/discharge928(for example, included in battery power supplemental logic). In some embodiments, battery power supplemental logic included in controller912can determine whether the power provided by the battery of the power supply system is to be supplemented or not from energy storage. In some embodiments, battery power supplemental logic included in controller912can include a voltage supplemental module that can determine whether to supplement the power provided by the battery based on, for example, the voltage currently being provided to the system load. This may be based on voltage monitoring hardware that provides voltage measurements to voltage supplemental module. In some embodiments, if the voltage droops below a threshold, or other predetermined level, yet is above the voltage minimum of the system, then voltage supplemental module can trigger and control the power supply system to have the power provided by the battery to be supplemented by power form the energy storage. This control may include turning on/off switches in the power delivery system to enable power to flow to the system load or to energy storage, and/or to protect other components in the system, to decouple the system load from the battery, etc. In some embodiments, battery power supplemental logic in controller912includes an energy storage charge and discharge module928that can control components in a hybrid power boost charging system such as, for example, system100to cause the energy storage to be charged at times and to be discharged and/or disabled at other times. Controller912can also include mode selection logic that determines when to enter a particular mode, such as, for example, a charging mode or a discharging mode. While not shown inFIG.9, controller912can include analog-to-digital converters (ADCs), filters, and a digital amplifier. One or more of the ADCs, filters, and digital amplifier may be, for example, an ASIC, a DSP, an FPGA, a processor, etc. These elements may be used to convert and analog measurement (for example, battery current and voltage) to a digital value for use in the battery charging control process. The digital amplifier may be a differential amplifier that generates an analog signal based on the voltage change (for example, voltage drop) across the battery (for example, the difference in voltage values between the positive and negative terminal of the battery), which is then converted to a filtered digital value using the ADC and the filter. In some embodiments, controller912includes a battery charger924to charge the battery using current charge from a power supply. In some embodiments, a critical voltage level of the system voltages when the protection is activated can be adjusted by the system Embedded Controller, the Fuel Gauge, or the SoC. The adjustment can be made based on the battery state of charge, peak power projections of the SoC or the rest of the platform, system impedance, or changes in system input decoupling, minimum system voltage, etc. In some embodiments, controller912can implement any of the techniques illustrated and/or described herein. In some embodiments, controller912can control peak power support and/or battery charge termination voltage adjustment. For example, in some embodiments, controller912can implement the flow400ofFIG.4and/or can implement the flow800ofFIG.8. FIG.10is a block diagram of an example of a computing device1000in accordance with some embodiments. In some embodiments, computing device1000may be a computing device including one or more elements of system100. For example, in some embodiments, computing device1000can implement any of the techniques illustrated and/or described herein. In some embodiments, one or more elements of computing device1000can be included in controller112, etc. In some embodiments, computing device1000can implement flow400and/or flow800. In some embodiments, computing device1000may provide any techniques or functions illustrated and/or described herein. In some embodiments, functions of computing device1000can include, for example, battery charge termination voltage adjustment, and/or any other techniques described and/or illustrated herein, etc., according to some embodiments. In some embodiments, any portion of the flow, circuits or systems illustrated in any one or more of the figures, and any of the embodiments illustrated and/or described herein can be included in or be implemented by computing device1000. The computing device1000may be, for example, a computing device, a controller, a control unit, an application specific controller, and/or an embedded controller, among others. The computing device1000may include a processor1002that is adapted to execute stored instructions (for example, instructions1003), as well as a memory device1004(or storage1004) that stores instructions1005that are executable by the processor1002. The processor1002can be a single core processor, a multi-core processor, a computing cluster, or any number of other configurations. For example, processor1002can be an Intel® processor such as an Intel® Celeron, Pentium, Core, Core i3, Core i5, or Core i7 processor. In some embodiments, processor1002can be an Intel® x86 based processor. In some embodiments, processor1002can be an ARM based processor. The memory device1004can be a memory device or a storage device, and can include volatile storage, non-volatile storage, random access memory, read only memory, flash memory, or any other suitable memory or storage systems. The instructions that are executed by the processor1002may also be used to implement hybrid power boost charging and/or discharging, battery charge termination voltage adjustment, etc. as illustrated and/or described in this specification. In some embodiments, processor1002may include the same or similar features or functionality as, for example, various controllers or agents in this disclosure. The processor1002may also be linked through the system interconnect1006(e.g., PCI®, PCI-Express®, NuBus, etc.) to a display interface1008adapted to connect the computing device1000to a display device1010. The display device1010may include a display controller1030. Display device1010may also include a display screen that is a built-in component of the computing device1000. The display device may also include a computer monitor, television, or projector, among others, that is externally connected to the computing device1000. In some embodiments, computing device1000does not include a display interface or a display device. In some embodiments, the display interface1008can include any suitable graphics processing unit, transmitter, port, physical interconnect, and the like. In some examples, the display interface1008can implement any suitable protocol for transmitting data to the display device1010. For example, the display interface1008can transmit data using a high-definition multimedia interface (HDMI) protocol, a DisplayPort protocol, or some other protocol or communication link, and the like In addition, a network interface controller (also referred to herein as a NIC)1012may be adapted to connect the computing device1000through the system interconnect1006to a network (not depicted). The network (not depicted) may be a cellular network, a radio network, a wide area network (WAN), a local area network (LAN), or the Internet, among others. The processor1002may be connected through system interconnect1006to an input/output (I/O) device interface1014adapted to connect the computing host device1000to one or more I/O devices1016. The I/O devices1016may include, for example, a keyboard or a pointing device, where the pointing device may include a touchpad or a touchscreen, among others. The I/O devices1016may be built-in components of the computing device1000, or may be devices that are externally connected to the computing device1000. In some embodiments, the processor1002may also be linked through the system interconnect1006to a storage device1018that can include a hard drive, a solid-state drive (SSD), a magnetic drive, an optical drive, a USB flash drive, an array of drives, or any other type of storage, including combinations thereof. In some embodiments, the storage device1018can include any suitable applications that can be used by processor1002to implement any of the techniques illustrated and/or described herein. In some embodiments, storage1018stores instructions1019that are executable by the processor1002. In some embodiments, the storage device1018can include a basic input/output system (BIOS). In some embodiments, a power device1022is provided. For example, in some embodiments, power device1022can provide peak power support, battery charge termination voltage adjustment, charging, power, power supply, power delivery, power management, peak power management, under-voltage protection, power control, voltage regulation, power generation, voltage generation, power protection, and/or voltage protection, etc. Power1022can also include any of the battery voltage adjustment illustrated and/or described herein. In some embodiments, power1022can include one or more sources of power supply such as one or more power supply units (PSUs). In some embodiments, power1022can be a part of system1000, and in some embodiments, power1022can be external to the rest of system1000. In some embodiments, power1022can provide any of peak power supply support, battery charge termination voltage adjustment, charging, discharging, power, power supply, power delivery, power management, peak power management, under-voltage protection, power control, voltage regulation, power generation, voltage generation, power protection, or voltage protection, power control, power adjustment, or any other techniques such as those illustrated and/or described herein. For example, in some embodiments, power1022can provide any of the techniques as described in reference to or illustrated in any of the drawings herein. FIG.10also illustrates system components1024. In some embodiments, system components1024can include any of display, camera, audio, storage, modem, or memory components, or any additional system components. In some embodiments, system components1024can include any system components for which power, voltage, power management, etc. can be implemented according to some embodiments as illustrated and/or described herein. It is to be understood that the block diagram ofFIG.10is not intended to indicate that the computing device1000is to include all of the components shown inFIG.10in all embodiments. Rather, the computing device1000can include fewer or additional components not illustrated inFIG.10(e.g., additional memory components, embedded controllers, additional modules, additional network interfaces, etc.). Furthermore, any of the functionalities of power device1022may be partially, or entirely, implemented in hardware or in a processor such as processor1002. For example, the functionality may be implemented with an application specific integrated circuit, logic implemented in an embedded controller, or in logic implemented in the processor1002, among others. In some embodiments, the functionalities of power device1022can be implemented with logic, wherein the logic, as referred to herein, can include any suitable hardware (e.g., a processor, among others), software (e.g., an application, among others), firmware, or any suitable combination of hardware, software, or firmware. In some embodiments, power device1022can be implemented with an integrated circuit. FIG.11is a block diagram of an example of one or more processors1102and one or more tangible, non-transitory computer readable media1100for peak power supply support, battery charger termination voltage adjustment, etc. The one or more tangible, non-transitory, computer-readable media1100may be accessed by the processor(s)1102over a computer interconnect1104. Furthermore, the one or more tangible, non-transitory, computer-readable media1100may include instructions (or code)1106to direct the processor(s)1102to perform operations as illustrated and/or described herein. In some embodiments, processor1102is one or more processors. In some embodiments, processor(s)1102can perform some or all of the same or similar functions that can be performed by other elements illustrated and/or described herein using instructions (code)1106included on media1100(for example, some or all of the functions or techniques illustrated in and/or described in reference to any ofFIGS.1-10). In some embodiments, one or more of processor(s)1102may include the same or similar features or functionality as, for example, various controllers, units, or agents, etc. illustrated and/or described in this disclosure. In some embodiments, one or more processor(s)1102, interconnect1104, and/or media1100may be included in computing device1000. Various components discussed in this specification may be implemented using software components. These software components may be stored on the one or more tangible, non-transitory, computer-readable media1100, as indicated inFIG.11. For example, peak power support and/or battery charge termination voltage adjustment, etc. may be adapted to direct the processor(s)1102to perform one or more of any of the operations described in this specification and/or in reference to the drawings. It is to be understood that any suitable number of software components may be included within the one or more tangible, non-transitory computer-readable media1100. Furthermore, any number of additional software components shown or not shown inFIG.11may be included within the one or more tangible, non-transitory, computer-readable media1100, depending on the specific application. The various techniques and/or operations described herein (for example, in reference to any one or more ofFIGS.1-10) may be performed by a control unit comprised of one or more processors, monitoring logic, control logic, software, firmware, agents, controllers, logical software agents, system agents, and/or other modules. For example, in some embodiments, some or all of the techniques and/or operations illustrated and/or described herein may be implemented by a system agent. Due to the variety of modules and their configurations that may be used to perform these functions, and their distribution through the system and/or in a different system, they are not all specifically illustrated in their possible locations in the figures. Reference in the specification to “one embodiment” or “an embodiment” or “some embodiments” of the disclosed subject matter means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosed subject matter. Thus, the phrase “in one embodiment” or “in some embodiments” may appear in various places throughout the specification, but the phrase may not necessarily refer to the same embodiment or embodiments. Example 1 In some examples, a control unit is configured to adjust charge termination voltage of a rechargeable energy storage device (for example, to adjust charge termination voltage of a battery). The control unit is adapted to charge the rechargeable energy storage device to a charge termination voltage where the rechargeable energy storage device has capacity to support peak load but comes close to a system shutdown voltage after supporting peak load, and to increase the charge termination voltage if a voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 2 includes the subject matter of example 1. The control unit is adapted to increase the charge termination voltage based on impedance of the rechargeable energy storage device. Example 3 includes the subject matter of any of examples 1-2. The control unit is adapted to monitor the impedance of the rechargeable energy storage device. Example 4 includes the subject matter of any of examples 1-3. The control unit is adapted to calculate the impedance of the rechargeable energy storage device based on monitored conditions. Example 5 includes the subject matter of any of examples 1-4. Monitored conditions include a voltage change of the rechargeable energy storage device and a sensed current. Example 6 includes the subject matter of any of examples 1-5. The control unit is adapted to increase the charge termination voltage a predetermined amount if the voltage of the rechargeable energy storage device is near the system shutdown voltage after supporting peak load. Example 7 includes the subject matter of any of examples 1-6. The control unit is adapted to continue to increase the charge termination voltage each time the voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 8 includes the subject matter of any of examples 1-7. The control unit is adapted to determine if the charge termination voltage has reached a safety threshold voltage. Example 9 includes the subject matter of any of examples 1-8. The control unit is adapted to provide a rechargeable energy storage device replacement needed notification if the charge termination voltage has reached the safety threshold voltage. Example 10 includes the subject matter of any of examples 1-9. The control unit is adapted to charge the rechargeable energy storage device to the safety threshold voltage if the charge termination voltage has reached the safety threshold voltage. Example 11 In some examples, a method can adjust charge termination voltage of a rechargeable energy storage device. The method can include charging the rechargeable energy storage device to a charge termination voltage where the rechargeable energy storage device has capacity to support peak load but comes close to a system shutdown voltage after supporting peak load, and increasing the charge termination voltage if a voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 12 includes the subject matter of example 11. The method includes increasing the charge termination voltage based on impedance of the rechargeable energy storage device. Example 13 includes the subject matter of any of examples 11-12. The method includes monitoring the impedance of the rechargeable energy storage device. Example 14 includes the subject matter of any of examples 11-13. The method includes calculating the impedance of the rechargeable energy storage device based on monitored conditions. Example 15 includes the subject matter of any of examples 11-14. Monitored conditions include a voltage change of the rechargeable energy storage device and a sensed current. Example 16 includes the subject matter of any of examples 11-15. The method includes increasing the charge termination voltage a predetermined amount if the voltage of the rechargeable energy storage device is near the system shutdown voltage after supporting peak load. Example 17 includes the subject matter of any of examples 11-16. The method includes continuing to increase the charge termination voltage each time the voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 18 includes the subject matter of any of examples 11-17. The method includes determining if the charge termination voltage has reached a safety threshold voltage. Example 19 includes the subject matter of any of examples 11-18. The method includes providing a rechargeable energy storage device replacement needed notification if the charge termination voltage has reached the safety threshold voltage. Example 20 includes the subject matter of any of examples 11-19. The method includes charging the rechargeable energy storage device to the safety threshold voltage if the charge termination voltage has reached the safety threshold voltage. Example 21 In some examples, one or more tangible, non-transitory machine readable media includes a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to charge the rechargeable energy storage device to a charge termination voltage where the rechargeable energy storage device has capacity to support peak load but comes close to a system shutdown voltage after supporting peak load, and to increase the charge termination voltage if a voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 22 includes the subject matter of example 21. The method one or more tangible, non-transitory machine readable media includes a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to increase the charge termination voltage based on impedance of the rechargeable energy storage device. Example 23 includes the subject matter of any of examples 21-22. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to monitor the impedance of the rechargeable energy storage device. Example 24 includes the subject matter of any of examples 21-23. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to calculate the impedance of the rechargeable energy storage device based on monitored conditions. Example 25 includes the subject matter of any of examples 21-24. Monitored conditions include a voltage change of the rechargeable energy storage device and a sensed current. Example 26 includes the subject matter of any of examples 21-25. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to increase the charge termination voltage a predetermined amount if the voltage of the rechargeable energy storage device is near the system shutdown voltage after supporting peak load. Example 27 includes the subject matter of any of examples 21-26. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to continue to increase the charge termination voltage each time the voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 28 includes the subject matter of any of examples 21-27. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to determine if the charge termination voltage has reached a safety threshold voltage. Example 29 includes the subject matter of any of examples 21-28. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to provide a rechargeable energy storage device replacement needed notification if the charge termination voltage has reached the safety threshold voltage. Example 30 includes the subject matter of any of examples 21-29. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to charge the rechargeable energy storage device to the safety threshold voltage if the charge termination voltage has reached the safety threshold voltage. Example 31 In some examples, a controller is configured to adjust charge termination voltage of a rechargeable energy storage device. The controller comprising includes means for charging the rechargeable energy storage device to a charge termination voltage where the rechargeable energy storage device has capacity to support peak load but comes close to a system shutdown voltage after supporting peak load, and means for increasing the charge termination voltage if a voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 32 includes the subject matter of example 31. The controller includes means for increasing the charge termination voltage based on impedance of the rechargeable energy storage device. Example 33 includes the subject matter of any of examples 31-32. The controller includes means for monitoring the impedance of the rechargeable energy storage device. Example 34 includes the subject matter of any of examples 31-33. The controller includes means for calculating the impedance of the rechargeable energy storage device based on monitored conditions. Example 35 includes the subject matter of any of examples 31-34. Monitored conditions include a voltage change of the rechargeable energy storage device and a sensed current. Example 36 includes the subject matter of any of examples 31-35. The controller includes means for increasing the charge termination voltage a predetermined amount if the voltage of the rechargeable energy storage device is near the system shutdown voltage after supporting peak load. Example 37 includes the subject matter of any of examples 31-36. The controller includes means for continuing to increase the charge termination voltage each time the voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 38 includes the subject matter of any of examples 31-37. The controller includes means for determining if the charge termination voltage has reached a safety threshold voltage. Example 39 includes the subject matter of any of examples 31-38. The controller includes means for providing a rechargeable energy storage device replacement needed notification if the charge termination voltage has reached the safety threshold voltage. Example 40 includes the subject matter of any of examples 31-39. The controller includes means for charging the rechargeable energy storage device to the safety threshold voltage if the charge termination voltage has reached the safety threshold voltage. Example 41 In some examples, a system can adjust charge termination voltage of a rechargeable energy storage device. The system includes a charger adapted to charge the rechargeable energy storage device and a control unit. The control unit is adapted to send a control signal to the charger to charge the rechargeable energy storage device to a charge termination voltage where the rechargeable energy storage device has capacity to support peak load but comes close to a system shutdown voltage after supporting peak load. The control unit is also to increase the charge termination voltage if a voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 42 includes the subject matter of example 41. The control unit is adapted to increase the charge termination voltage based on impedance of the rechargeable energy storage device. Example 43 includes the subject matter of any of examples 41-42. The control unit is adapted to monitor the impedance of the rechargeable energy storage device. Example 44 includes the subject matter of any of examples 41-43. The control unit is adapted to calculate the impedance of the rechargeable energy storage device based on monitored conditions. Example 45 includes the subject matter of any of examples 41-44. Monitored conditions include a voltage change of the rechargeable energy storage device and a sensed current. Example 46 includes the subject matter of any of examples 41-45. The system includes a current sensor adapted to sense current. The control unit is adapted to increase the charge termination voltage based on (or in response to) the sensed current. Example 47 includes the subject matter of any of examples 41-46. The control unit is adapted to increase the charge termination voltage a predetermined amount if the voltage of the rechargeable energy storage device is near the system shutdown voltage after supporting peak load. Example 48 includes the subject matter of any of examples 41-47. The control unit is adapted to continue to increase the charge termination voltage each time the voltage of the rechargeable energy storage device is near a system shutdown voltage after supporting peak load. Example 49 includes the subject matter of any of examples 41-48. The control unit is adapted to determine if the charge termination voltage has reached a safety threshold voltage. Example 50 includes the subject matter of any of examples 41-49. The control unit is adapted to provide a rechargeable energy storage device replacement needed notification if the charge termination voltage has reached the safety threshold voltage. Example 51 includes the subject matter of any of examples 41-50. The control unit is adapted to charge the rechargeable energy storage device to the safety threshold voltage if the charge termination voltage has reached the safety threshold voltage. Example 52 In some examples, a control unit is configured to adjust charge termination voltage of a rechargeable energy storage device, including means to perform a method as in any other example. Example 53 In some examples, an apparatus is configured to adjust charge termination voltage. The apparatus includes a controller to adjust a charge termination voltage of a charger of a rechargeable energy storage device based on a comparison of a first threshold level with the voltage of the rechargeable energy storage device during peak load, wherein the charge termination voltage is a voltage at which the rechargeable energy storage device has capacity to support peak load of a system, and to adjust the charge termination voltage based on a comparison of a second threshold level with an end voltage of the rechargeable energy storage device after peak load. Example 54 includes the subject matter example 53. The controller is to adjust the charge termination voltage based on a temperature of the rechargeable energy storage device. Example 55 includes the subject matter of any of examples 53-54. The controller is to adjust the charge termination voltage based on an impedance of the rechargeable energy storage device. Example 56 includes the subject matter of any of examples 53-55. The impedance includes an ohmic portion and a polarization portion. Example 57 includes the subject matter of any of examples 53-56. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more temperatures of the rechargeable energy storage device. Example 58 includes the subject matter of any of examples 53-57. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more impedances of the rechargeable energy storage device. Example 59 includes the subject matter of any of examples 53-58. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device. Example 60 includes the subject matter of any of examples 53-59. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device, or based on one or more predicted future temperatures of the rechargeable energy storage device, or based on both historical and predicted future temperatures of the rechargeable energy storage device. Example 61 includes the subject matter of any of examples 53-60. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device. Example 62 includes the subject matter of any of examples 53-61. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device, or based on one or more predicted future impedances of the rechargeable energy storage device, or based on both historical and predicted future impedances of the rechargeable energy storage device. Example 63 includes the subject matter of any of examples 53-62. The controller is to increase the charge termination voltage based on the comparison of the first threshold level with the voltage of the rechargeable energy storage device during peak load, and to decrease the charge termination voltage based on the comparison of the second threshold level with the end voltage of the rechargeable energy storage device after peak load. Example 64 includes the subject matter of any of examples 53-63. The second threshold level is higher than the first threshold level. Example 65 includes the subject matter of any of examples 53-64. The controller is to adjust a charge current of the rechargeable energy storage device or a discharge current of the rechargeable energy storage device, or both the charge current of the rechargeable energy storage device and the discharge current of the rechargeable energy storage device, to manage temperature of the rechargeable energy storage device. Example 66 includes the subject matter of any of examples 53-65. The apparatus includes the charger. The charger is to charge the rechargeable energy storage device to a charge termination voltage at which the rechargeable energy storage device has capacity to support peak load of a system. Example 67 In some examples, an apparatus is to adjust charge termination voltage. The apparatus includes a charger to charge a rechargeable energy storage device to a charge termination voltage at which the rechargeable energy storage device has capacity to support peak load of a system. The apparatus also includes a controller to adjust a charge termination voltage of a rechargeable energy storage device based on a comparison of a first threshold level with the voltage of the rechargeable energy storage device during peak load, and to adjust the charge termination voltage based on a comparison of a second threshold level with an end voltage of the rechargeable energy storage device after peak load. Example 68 includes the subject matter of example 67. The controller is to adjust the charge termination voltage based on a temperature of the rechargeable energy storage device. Example 69 includes the subject matter of any of examples 67-68. The controller is to adjust the charge termination voltage based on an impedance of the rechargeable energy storage device. Example 70 includes the subject matter of any of examples 67-69. The impedance includes an ohmic portion and a polarization portion. Example 71 includes the subject matter of any of examples 67-70. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more temperatures of the rechargeable energy storage device. Example 72 includes the subject matter of any of examples 67-71. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more impedances of the rechargeable energy storage device. Example 73 includes the subject matter of any of examples 67-72. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device. Example 74 includes the subject matter of any of examples 67-73. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device, or based on one or more predicted future temperatures of the rechargeable energy storage device, or based on both historical and predicted future temperatures of the rechargeable energy storage device. Example 75 includes the subject matter of any of examples 67-74. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device. Example 76 includes the subject matter of any of examples 67-75. The controller is to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device, or based on one or more predicted future impedances of the rechargeable energy storage device, or based on both historical and predicted future impedances of the rechargeable energy storage device. Example 77 includes the subject matter of any of examples 67-76. The controller is to increase the charge termination voltage based on the comparison of the first threshold level with the voltage of the rechargeable energy storage device during peak load, and to decrease the charge termination voltage based on the comparison of the second threshold level with the end voltage of the rechargeable energy storage device after peak load. Example 78 includes the subject matter of any of examples 67-77. The second threshold level is higher than the first threshold level. Example 79 includes the subject matter of any of examples 67-79. The controller is to adjust a charge current of the rechargeable energy storage device or a discharge current of the rechargeable energy storage device, or both the charge current of the rechargeable energy storage device and the discharge current of the rechargeable energy storage device, to manage temperature of the rechargeable energy storage device. Example 80 In some examples, a method is to adjust charge termination voltage. The method includes adjusting a charge termination voltage of a charger of a rechargeable energy storage device based on a comparison of a first threshold level with the voltage of the rechargeable energy storage device during peak load, wherein the charge termination voltage is a voltage at which the rechargeable energy storage device has capacity to support peak load of a system, and adjusting the charge termination voltage based on a comparison of a second threshold level with an end voltage of the rechargeable energy storage device after peak load. Example 81 includes the subject matter of example 80. The method includes adjusting the charge termination voltage based on a temperature of the rechargeable energy storage device. Example 82 includes the subject matter of any of examples 80-81. The method includes adjusting the charge termination voltage based on an impedance of the rechargeable energy storage device. Example 83 includes the subject matter of any of examples 80-82. The impedance includes an ohmic portion and a polarization portion. Example 84 includes the subject matter of any of examples 80-83. The method includes adjusting the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more temperatures of the rechargeable energy storage device. Example 85 includes the subject matter of any of examples 80-84. The method includes adjusting the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more impedances of the rechargeable energy storage device. Example 86 includes the subject matter of any of examples 80-85. The method includes adjusting the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device. Example 87 includes the subject matter of any of examples 80-86. The method includes adjusting the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device, or based on one or more predicted future temperatures of the rechargeable energy storage device, or based on both historical and predicted future temperatures of the rechargeable energy storage device. Example 88 includes the subject matter of any of examples 80-87. The method includes adjusting the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device. Example 89 includes the subject matter of any of examples 80-88. The method includes adjusting the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device, or based on one or more predicted future impedances of the rechargeable energy storage device, or based on both historical and predicted future impedances of the rechargeable energy storage device. Example 90 includes the subject matter of any of examples 80-89. The method includes increasing the charge termination voltage based on the comparison of the first threshold level with the voltage of the rechargeable energy storage device during peak load, and decreasing the charge termination voltage based on the comparison of the second threshold level with the end voltage of the rechargeable energy storage device after peak load. Example 91 includes the subject matter of any of examples 80-90. The second threshold level is higher than the first threshold level. Example 92 includes the subject matter of any of examples 80-91. The method includes adjusting a charge current of the rechargeable energy storage device or a discharge current of the rechargeable energy storage device, or both the charge current of the rechargeable energy storage device and the discharge current of the rechargeable energy storage device, to manage temperature of the rechargeable energy storage device. Example 93 In some examples, one or more tangible, non-transitory machine readable media includes a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust a charge termination voltage of a charger of a rechargeable energy storage device based on a comparison of a first threshold level with the voltage of the rechargeable energy storage device during peak load, wherein the charge termination voltage is a voltage at which the rechargeable energy storage device has capacity to support peak load of a system, and to adjust the charge termination voltage based on a comparison of a second threshold level with an end voltage of the rechargeable energy storage device after peak load. Example 94 includes the subject matter of example 93. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the charge termination voltage based on a temperature of the rechargeable energy storage device. Example 95 includes the subject matter of any of examples 93-94. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the charge termination voltage based on an impedance of the rechargeable energy storage device. Example 96 includes the subject matter of any of examples 93-95. The impedance includes an ohmic portion and a polarization portion. Example 97 includes the subject matter of any of examples 93-96. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more temperatures of the rechargeable energy storage device. Example 98 includes the subject matter of any of examples 93-97. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more impedances of the rechargeable energy storage device. Example 99 includes the subject matter of any of examples 93-98. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device. Example 100 includes the subject matter of any of examples 93-99. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical temperatures of the rechargeable energy storage device, or based on one or more predicted future temperatures of the rechargeable energy storage device, or based on both historical and predicted future temperatures of the rechargeable energy storage device. Example 101 includes the subject matter of any of examples 93-100. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device. Example 102 includes the subject matter of any of examples 93-101. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust the first threshold or the second threshold, or both the first threshold and the second threshold, based on one or more historical impedances of the rechargeable energy storage device, or based on one or more predicted future impedances of the rechargeable energy storage device, or based on both historical and predicted future impedances of the rechargeable energy storage device. Example 103 includes the subject matter of any of examples 93-102. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to increase the charge termination voltage based on the comparison of the first threshold level with the voltage of the rechargeable energy storage device during peak load, and to decrease the charge termination voltage based on the comparison of the second threshold level with the end voltage of the rechargeable energy storage device after peak load. Example 104 includes the subject matter of any of examples 93-103. The second threshold level is higher than the first threshold level. Example 105 includes the subject matter of any of examples 93-104. The one or more tangible, non-transitory machine readable media include a plurality of instructions that, in response to being executed on at least one processor, cause the at least one processor to adjust a charge current of the rechargeable energy storage device or a discharge current of the rechargeable energy storage device, or both the charge current of the rechargeable energy storage device and the discharge current of the rechargeable energy storage device, to manage temperature of the rechargeable energy storage device. Example 106 In some examples, machine-readable storage includes machine-readable instructions, when executed, to implement a method or realize an apparatus as in any other example. Example 107 In some examples, one or more machine readable medium include(s) code, when executed, to cause a machine to perform the method of any other example. Example 108 In some examples, an apparatus includes means to perform a method as in any other example. Example 109 In some examples, an apparatus includes a control unit. The apparatus includes means to perform a method as in any other example. Although example embodiments and examples of the disclosed subject matter are described with reference to circuit diagrams, flow diagrams, block diagrams etc. in the drawings, persons of ordinary skill in the art will readily appreciate that many other ways of implementing the disclosed subject matter may alternatively be used. For example, the arrangements of the elements in the diagrams, or the order of execution of the blocks in the diagrams may be changed, or some of the circuit elements in circuit diagrams, and blocks in block/flow diagrams described may be changed, eliminated, or combined. Any elements as illustrated or described may be changed, eliminated, or combined. In the preceding description, various aspects of the disclosed subject matter have been described. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the subject matter. However, it is apparent to one skilled in the art having the benefit of this disclosure that the subject matter may be practiced without the specific details. In other instances, well-known features, components, or modules were omitted, simplified, combined, or split in order not to obscure the disclosed subject matter. Various embodiments of the disclosed subject matter may be implemented in hardware, firmware, software, or combination thereof, and may be described by reference to or in conjunction with program code, such as instructions, functions, procedures, data structures, logic, application programs, design representations or formats for simulation, emulation, and fabrication of a design, which when accessed by a machine results in the machine performing tasks, defining abstract data types or low-level hardware contexts, or producing a result. Program code may represent hardware using a hardware description language or another functional description language which essentially provides a model of how designed hardware is expected to perform. Program code may be assembly or machine language or hardware-definition languages, or data that may be compiled or interpreted. Furthermore, it is common in the art to speak of software, in one form or another as taking an action or causing a result. Such expressions are merely a shorthand way of stating execution of program code by a processing system which causes a processor to perform an action or produce a result. Program code may be stored in, for example, one or more volatile or non-volatile memory devices, such as storage devices or an associated machine readable or machine accessible medium including solid-state memory, hard-drives, floppy-disks, optical storage, tapes, flash memory, memory sticks, digital video disks, digital versatile discs (DVDs), etc., as well as more exotic mediums such as machine-accessible biological state preserving storage. A machine readable medium may include any tangible mechanism for storing, transmitting, or receiving information in a form readable by a machine, such as antennas, optical fibers, communication interfaces, etc. Program code may be transmitted in the form of packets, serial data, parallel data, etc., and may be used in a compressed or encrypted format. Program code may be implemented in programs executing on programmable machines such as mobile or stationary computers, personal digital assistants, set top boxes, cellular telephones and pagers, and other electronic devices, each including a processor, volatile or non-volatile memory readable by the processor, at least one input device or one or more output devices. Program code may be applied to the data entered using the input device to perform the described embodiments and to generate output information. The output information may be applied to one or more output devices. One of ordinary skill in the art may appreciate that embodiments of the disclosed subject matter can be practiced with various computer system configurations, including multiprocessor or multiple-core processor systems, minicomputers, mainframe computers, as well as pervasive or miniature computers or processors that may be embedded into virtually any device. Embodiments of the disclosed subject matter can also be practiced in distributed computing environments where tasks may be performed by remote processing devices that are linked through a communications network. Although operations may be described as a sequential process, some of the operations may in fact be performed in parallel, concurrently, or in a distributed environment, and with program code stored locally or remotely for access by single or multi-processor machines. In addition, in some embodiments the order of operations may be rearranged without departing from the spirit of the disclosed subject matter. Program code may be used by or in conjunction with embedded controllers. While the disclosed subject matter has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the subject matter, which are apparent to persons skilled in the art to which the disclosed subject matter pertains are deemed to lie within the scope of the disclosed subject matter. For example, in each illustrated embodiment and each described embodiment, it is to be understood that the diagrams of the figures and the description herein is not intended to indicate that the illustrated or described devices include all of the components shown in a particular figure or described in reference to a particular figure. In addition, each element may be implemented with logic, wherein the logic, as referred to herein, can include any suitable hardware (e.g., a processor, among others), software (e.g., an application, among others), firmware, or any suitable combination of hardware, software, and firmware, for example. | 126,446 |
11863010 | DETAILED DESCRIPTION Various embodiments of a photovoltaic power continuity device having a battery pack are described below and illustrated in the associated drawings. Unless otherwise specified, the photovoltaic power continuity device and/or its various components may, but are not required to, contain at least one of the structures, components, functionality, and/or variations described, illustrated, and/or incorporated herein. Furthermore, the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein in connection with the present teachings may, but are not required to, be included in other similar apparatuses. The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. Additionally, the advantages provided by the embodiments, as described below, are illustrative in nature and not all embodiments provide the same advantages or the same degree of advantages. FIG.1is a schematic diagram of a power continuity unit, generally indicated at100, associated with a solar panel102. Power continuity unit100includes a battery pack104, a power converter106, and a housing assembly107. In the embodiment ofFIG.1, the battery pack104includes a rechargeable plurality of lithium-titanite or lithium-titanite oxide (LTO) battery cells108. LTO battery cells have a relatively long life-cycle and can charge and discharge over a significantly higher temperature range than other commercially available rechargeable battery cells. These cells may be highly efficient for storing and recovering energy, potentially with less than 1% of the stored energy lost as heat. In this embodiment, the battery cells108may be prismatic and may be positioned side-to-side, which giving the battery pack104the ability to fit into a flat, compact housing assembly107. One example of a suitable cell for use in this embodiment is the SCiB™ rechargeable cell manufactured by the Toshiba Corporation of Tokyo, Japan. The battery cells may be electrically connected to one another through any appropriate combination of series and parallel electrical connections. In some examples, ten battery cells may be electrically connected to one another in series within a battery pack104. In some examples, battery pack104may include two subgroups of battery cells connected in series with one another, with the two subgroups connected in parallel with one another. For example, ten series-connected battery cell cells may be connected in parallel with another ten series-connected battery cell cells. In some examples, more than two subgroups of battery cell cells may be connected with one another in parallel, with the battery cells within each subgroup connected in series. In this embodiment, the housing assembly107may comprises a single casing110enclosing both the battery pack104and the power conversion unit106. The casing110may be rectangular and relatively flat in configuration to best accommodate the flat, rectangular shape of prismatic battery cells108, and may be made of aluminum or other material capable of dissipating heat generated by components within power converter device106. The ability of LTO battery cells to withstand extreme temperatures eliminates the need for insulation in this embodiment. Battery case110may further include a plurality of monitoring devices132. Each monitoring device132of the plurality of monitoring devices may be configured to be associated with one of the plurality of battery cells108. Each monitoring device may be configured to monitor the temperature and/or voltage of the associated battery cell. Each monitoring device may be configured to be connected to the associated battery cell through electrical connections126. Each monitoring device may be configured to trim excess voltage over an optimal voltage for the associated battery cell. The plurality of monitoring devices may be part of a feedback loop or feedback system configured to help operate power continuity unit100as efficiently as is possible. Power converter106may be configured to be electrically connected, shown schematically at841, to the plurality of battery cells108. That is, power converter106may be configured to be electrically connected to the electrical connections126within the battery pack. The power converter106may be configured to be electrically connected, shown schematically at144, to the associated alternative energy device102. The power converter106may be configured to be electrically connected, shown schematically at146, to a power grid148. Power converter106may be, at least partially, a computing device and may include a processor, a memory, and a program including a set of instructions stored in the memory and executable by the processor to perform a variety of functions relating to converting, storing, and releasing electrical energy via power continuity unit100. Power converter106may be configured to be connected to, or in communication with, one or more computing devices across a network, such as the plurality of monitoring devices132within the battery pack, a power converter device from another power continuity unit, a central server configured to monitor one or more power continuity units, or some other computing device. As shown schematically inFIG.8, power converter106includes a DC-to-DC converter810that is configured to receive DC output from solar panel(s)102through electrical connections144and to convert this relatively high voltage output to the lower voltage needed to charge the cells in battery pack104. The DC-to-DC converter810uses maximum power point tracking (MPPT) to optimize the efficiency of power transfer from the solar panel. Output from the DC-to-DC converter810is then directed to AC circuit (power grid)148, battery pack(s)104, or both, as needed. Grid switch150controls the flow of power between the DC-to-AC inverter812and the AC circuit148, and an optional pack disconnect switch814can be added to control the flow of power between the DC-to-DC converter810and the battery pack(s)104. In addition, the power converter106may optionally include an AC-to-DC converter816that allows the battery pack104to be charged with incoming power from the AC circuit148. Ideally, battery pack104includes a cell balancing circuit818which optimizes the distribution of power between the cells to improve the available capacity of the battery pack104and increase the longevity of each individual cell. Power converter106may be configured to receive monitoring data from the plurality of monitoring devices132in battery pack104. The power converter106may alter the power directed to plurality of battery cells108in the battery pack based on the received monitoring data. The power conversion unit may alter the amount of stored electrical energy which is converted into AC power based on the received monitoring data. In some examples, power converter106may be configured to receive voltage data from the plurality of monitoring devices132associated with the plurality of battery cells108within battery pack104. The power conversion unit may be configured to alter the portion of DC power directed to one battery cell of the plurality of battery cells within the battery pack base on the received voltage data from the monitoring device associated with the one battery cell of the plurality of battery cells. This may ensure that each of the battery cells is always at the same optimal voltage, which may help the battery pack achieve a maximum possible lifetime. Switch150may alternately couple and decouple power continuity unit100from power grid148. In some examples, switch150may be an automatic switch that either opens or closes in response to a stimulus external to the power continuity unit or to a stimulus internal to the power continuity unit. In some examples, switch150may be operated selectively by a user such as an owner or operator of power continuity unit100. In some examples, switch150may be a cut-on switch configured to allow a user to selectively connect power continuity unit100to an external power grid such as power grid148. All or part of power continuity unit100may be sized and/or configured to fit beneath most commercially available solar panels. In some examples, the power continuity unit100may be configured to be attached to a racking system for the solar panel. In some examples, the housing assembly107may be sized to fit in a space beneath a solar panel without obstructing solar radiation incident on the solar panel. In some examples, power continuity unit100may be integrated with an associated solar panel102and may be configured for connection to a solar panel array. That is, the power continuity unit may be a separate product which can be used with a commercially available solar panel, or the solar panel and power continuity unit may be integrated into a single product. In some cases, the solar panel and power continuity unit may be integrated into a single device, such as a roofing tile, and may include connection points for electrically connecting the device into a solar panel array. Installation costs of a solar panel array, including one or more power continuity units as disclosed herein, may be reduced through automation of the installation process. In some examples, a drone could be used to scan the three-dimensional structure of a roof and a computing device could use the results of that scan to determine an optimal configuration for a solar panel array installed on that roof. One or more drones could then install a racking system on the roof, install one or more power continuity units, and/or install one or more solar panels. Using such a system, an entire solar panel array could be installed quickly and safely by a single operator. FIG.2shows an alternate embodiment200of the invention, which, except as mentioned, is identical to the embodiment ofFIG.1, except that the LTO 208 cells in the battery pack204are cylindrical in configuration and are positioned end-to-end, allowing the battery pack204to fit into a tubular casing210. The ends212,214of the casing210are shown here to be closed, but they may be open if needed to provide better structural support. The embodiments ofFIGS.3and5are recommended for use with non-LTO battery cells which may have higher inherent voltage and energy density than LTO battery cells, but are not capable of withstanding extreme temperatures. The embodiments are also appropriate for LTO battery cells in environments where the ambient temperature is expected to fall below or rise above the normal temperature range for LTO battery cells. The housing assembly307for the embodiment ofFIG.3includes a battery casing310surrounding the battery pack304and a converter casing340surrounding the power converter306, which functions in the same ways as the power converter106ofFIG.1. The battery casing310is preferably made from a material such as fiberglass which provides structural support as well as some degree of insulation for the battery cells. If necessary, one or more inner surfaces of the battery casing310may be lined with an additional layer of thermal insulating material342to reduce the absorption of heat from the roof top or other surface on which the power continuity unit300is supported. The converter casing340, which may be snapped or otherwise secured to one end of the battery casing310, may be made of a heat-dissipating material such as aluminum to allow rapid dissipation of heat generated by components within power converter306. Each battery cell308in the battery pack304is enclosed in its own individual vacuum thermos316. Each thermos316is configured to provide thermal insulation for the enclosed battery308. Alternatively stated, the thermoses316are configured to limit or impede the flow of thermal energy to and from the battery cells108, via any or all of conduction, convention, or radiation. Each thermos316may include an inner portion318and an outer portion320. Inner portion316may be configured to receive battery308in a thermos interior322. Outer portion320may be configured to at least partially enclose inner portion318and thereby define a vacuum space324between the inner portion and the outer portion. Either or both of the inner and outer portions may be formed of stainless steel or aluminum. In some examples, the vacuum space324between the inner portion318and the outer portion320may be substantially depleted of air. In some examples, the vacuum space may contain an insulating material, such as a foam material, configured to inhibit the flow of air within the vacuum space. Each thermos of the plurality of thermoses316may include a passage325from outer portion320to thermos interior322. The passage325may be configured to receive electrical connections326to the enclosed battery and permit air to flow from a space exterior to outer portion318to the thermos interior322. The passage325may also receive an electrical connector joining a temperature sensor332mounted on outer portion320to a temperature sensor within thermos interior322. In some examples, passage325may include a tube extending from outer portion320to inner portion318. In some examples, passage325may include more than one passage, for example two passages, between a space exterior to the thermos to the thermos interior. Passage325may be configured to provide structural separation between the inner and outer portions. A cooling manifold334may be included within the battery casing. Cooling manifold334may include one or more pipes, passages, or other tubes which may be configured to be connected to a source of forced air and to deliver that air to the interior space of the thermoses. The cooling manifold may also include one or more pipes, passages, or other tubes to carry a flow of air away from or out of one or more of the thermos interiors. The cooling manifold334may be coupled to a fluid circulator such as a pump or Tim336located within the converter housing340and configured to drive fluid flow to the plurality of battery cells308within battery pack304. In some examples, fluid circulator336may drive the flow of fluid generally through an interior space338of the battery pack without using manifold334to direct the fluid flow directly to the thermos interiors322. In these cases, a cooling flow of air or liquid may enter the thermos interiors through passages324from the interior space338of the batter pack. In some examples, the fluid circulator may be a fan336configured to drive a flow of atmospheric air to plurality of battery cells308within battery pack304, perhaps through manifold334. In other examples, fluid circulator may be a pump configured to drive a flow of cooling liquid to the plurality of battery cells, perhaps through manifold334. The fan or pump may be coupled to manifold334automatically or concurrently with coupling power converter device306to battery pack304. In some examples, power converter306may be configured to receive temperature data from monitoring devices332associated with plurality of battery cells308within battery pack304. The power conversion unit may be configured to operate fan336in response to the received temperature data from the plurality of monitoring devices. Converter306may be connected to fluid circulator316by electrical connections350and may operate the fan as part of a feedback loop configured to keep the battery cells from reaching a maximum allowable temperature. The plurality of battery cells308may have at least three separate thermal protections against elevated temperatures: outer casing310, the plurality of thermoses316, and a flow of cooling fluid provided by the fluid circulator (fan)336. FIG.4shows one of the battery/thermos units ofFIG.3in greater detail. A few methods are possible for enclosing each battery308within a thermos316. One method includes first enclosing the battery within the inner portion316. Inner portion316may include one or more ports354through which electrical connections326may extend. Air flow, indicated by arrows356, may also pass through ports354. Battery308may be enclosed within inner portion316by welding a top piece360of the inner portion to a bottom piece362of the inner portion with the battery disposed between the top piece and the bottom piece. Any appropriate welding technique may be used, such as conventional welding or induction welding. Passages325may subsequently be created in the inner portion316so that passages325are fluidly connected to ports354, for example by welding tubes to the top piece360of the inner portion. Outer portion318may then be attached to the passages325. Outer portion318may include one or more ports364fluidly connected to passages325. Outer portion318may include a top piece366and bottom piece368which may be welded together thereby enclosing the inner portion316and defining the vacuum space324between the outer and inner portions. In some examples, outer portion318of each of the plurality of thermoses316may include a port370through which air can be removed from vacuum space322between inner portion316and outer portion318. That is, air may be substantially removed from the vacuum space by drawing the air through vacuum port370and subsequently sealing the vacuum port. In some examples, the order of the steps for assembling the thermos may be changed. For example, the air may be evacuated from the vacuum space prior to welding together the top and bottom pieces of the inner portion and/or the outer portion. In the embodiment ofFIG.5, cylindrical battery cells508are arranged end-to-end and encased in a single elongated vacuum thermos514which, like the thermos314ofFIG.4, comprises an inner portion516and an outer portion518separated by a vacuum space522. The vacuum thermos514is surrounded by an external heat-dissipating housing519which also encloses the converter506. FIG.6is a schematic diagram of a power continuity unit according to the present disclosure, generally indicated at600, associated with a wind turbine601. The wind turbine tower wall611includes a lower portion612that encases a plurality of battery cells608and an upper portion634that encases a power converter606which function as the same manner as the power converter106ofFIG.1. Together, the lower portion612and upper portion634of the wind turbine tower wall611constitute a housing assembly. If the battery cells608are LTO cells, the lower and upper portions612,634of the wind turbine tower wall611may both be formed of a heat-dissipating material such as aluminum, and may constitute an integral unit. If non-LTO cells are used, the upper and lower portions612,634may be formed of different materials and coupled to one another by any appropriate means. The lower portion612of the wind turbine tower wall611may be formed of an insulating material such as the fiberglass used in the embodiment ofFIG.3and/or may include an additional insulating layer642. The upper portion634of the wind turbine tower wall611may be formed of a heat dissipating material similar to the heat-dissipating material used in the housing of the power converter device ofFIG.3, and may include structural components, such as fins, to improve its heat dissipating qualities. Further, if the battery cells308are not LTO cells, each individual cell may be encased in its own individual thermos, as in the embodiment ofFIGS.3and4, or the entire tower wall611may be formed as a vacuum thermos encasing all the battery cells608, similar to the embodiment ofFIG.5. As in the previous embodiments, the battery units608may be electrically connected to one another through any appropriate combination of series and parallel electrical connections. In the illustrated example, five series-connected battery units608are connected in parallel with another series-connected battery units608. Each of the battery units608may be associated with a monitoring device632similar to the monitoring devices of the previous embodiments. The battery units608are coupled by electrical connections626,649to a converter606that is coupled by electrical connector644to an electrical generator system602that is in rum connected by turbine shaft609to rotating turbine blades611. The converter606may be coupled by electrical connector646to a power grid648. A fluid circulator636may also be housed within the interior of the wind turbine tower, and configured to drive cooling fluid to the battery units608, either through a manifold or through the interior638of the wind turbine tower, without using a manifold. The fluid circulator may be coupled by electrical connection649to the converter606. As in the previous embodiments, the power continuity unit600may include a switch650for alternately coupling and decoupling the power continuity unit600from the power grid648. The switch650may be an automatic switch that opens or closes in response to external or internal stimuli, or it may be a manual switch operated selectively by an owner or operator of the power continuity unit600. In some examples, the switch650may be a cut-on switch configured to allow a user to selectively connect the power continuity unit600to the power grid648. FIGS.7A, B, and C show the programming logic behind the control system for the power converter106ofFIG.1. Each block and/or combination of blocks in a flowchart and/or block diagram may be implemented by computer program instructions. The computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or Hock diagram block or blocks. These computer program instructions can also be stored in a computer-readable medium that can direct a computer, other programmable data processing apparatus, and/or other device to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions can also be loaded onto a computer, other programmable data processing apparatus, and/or other device to cause a series of operational steps to be performed on the device to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. Any flowchart and/or block diagram in the drawings is intended to illustrate the architecture, functionality, and/or operation of possible implementations of systems, methods, and computer program products according to aspects of the photovoltaic power continuity device. In this regard, each block may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). In some implementations, the functions noted in the block may occur out of the order noted in the drawings. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Each block and/or combination of blocks may be implemented by special purpose hardware-based systems (or combinations of special purpose hardware and computer instructions) that perform the specified functions or acts. Specifically,FIG.7Ashows a startup routine700;FIG.7Bshows an algorithm710for connecting to a power grid; andFIG.7Cshows an optional subroutine720for users who wish to maximize their profit when selling power back to the grid. At the beginning the startup routine700shown inFIG.7A, the controller checks whether photovoltaic power is available (step701) and if so, confirms that the system is turned on (step702). Once this has been confirmed, the power converter106is turned on (step703), and the controller moves on to the connection algorithm710shown inFIG.7B. At step711of the connection algorithm710the controller receives input from the monitoring devices on the battery cells to determine how much power is being drawn. If at step712, the controller determines that the power drawn is greater than the load, it sends the excess power to the battery cells (step713). If not, the controller checks whether the power is equal to the load (step714) and if so, returns to step712. If the power is less than the load, the controller checks whether battery energy is available (step715). If battery energy is available, the controller cycles back to step711. If battery energy is not available and the system is normally off grid mode (step716), the controller checks whether grid power is present (step717) and if so, connects to the grid (step719) to receive more power. If grid power is not present, the system outputs a low power signal (step718). In the optional subroutine720shown inFIG.7C, the controller checks whether the system has been set to Maximum profit mode (step721) and if so, whether there is excess power to sell (step722). If there is excess power, the system then connects to the grid (step723) and sends the excess power to the grid (step724) The battery cells are then recharged during off-peak hours (step725). The different embodiments of the alternative energy continuity unit described herein provide several advantages over known solutions for storing and subsequently releasing electrical energy generated by alternative energy devices. For example, the illustrative embodiments of power continuity units described herein allow for three separate controls over the temperature of a plurality of rechargeable battery cells of the power continuity units. The power continuity units also allow the use of smaller power transmission cables than are required for conventional solar or wind energy devices or systems. Additionally, and among other benefits, illustrative embodiments of the power continuity unit described herein allow for more efficient control over the electrical energy stored in the plurality of battery cells and retrieved from the battery cells. No known system or device can perform these functions, particularly as a single unit which can be configured to be used with most commercially available solar panels or installed inside a wind turbine tower. Thus, the illustrative embodiments described herein are particularly useful for use in existing alternative energy devices or systems. However, not all embodiments described herein provide the same advantages or the same degree of advantage. The disclosure set forth above may encompass multiple distinct inventions with independent utility. Although each of these inventions has been disclosed in its preferred form(s), the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. To the extent that section headings are used within this disclosure, such headings are for organizational purposes only, and do not constitute a characterization of any claimed invention. The subject matter of the invention(s) includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. Invention(s) embodied in other combinations and subcombinations of features, functions, elements, and/or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether directed to a different invention or to the same invention, and whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the invention(s) of the present disclosure. | 28,186 |
11863011 | DETAILED DESCRIPTION Referring toFIG.2, a block diagram of a micro-inverter system according to one aspect of the present invention is illustrated. The system illustrated inFIG.2has the capability of accepting DC power either from a PV (or any renewable energy source) or from an energy storage device (such as a battery). As can be seen from the figure, the microinverter has multiple DC inputs that can be connected to either a PV panel or an energy storage unit (e.g., a battery). The micro-inverter system10includes four DC/DC converters20A,20B,20C,20D, a DC/AC inverter30, a control system40, and a communication block50. The control system is capable of automatically determining whether the DC/DC converters20A-20D are coupled to a renewable power source or an energy storage device. The control system40can automatically perform maximum power point tracking or control the discharge of the energy storage device depending on what it detects the relevant converter is coupled to. The DC/AC inverter30converts the DC power into AC power compatible with the grid and/or loads. The control system40generates the gate pulses for the converters20A-20D and closed-loop controllers for the converters are implemented in this control system block40. The control system40also receives and transmits information through the communication block50. It should also be clear that the energy storage device may be coupled, in turn, to a separate renewable energy source. The energy storage device can then be charged by the renewable energy source Referring toFIG.3, the control system40includes multiple DC/DC Converter Control System blocks100and a DC/AC Inverter Control System block110. Each DC/DC converter control system block controls a single DC/DC converter while the DC/AC inverter control system block110controls the DC/AC inverter30. Each DC/DC Converter Control System block100receives the input voltage (vdcn) and current (idcn) of the DC/DC converter that it controls and generates the gate pulses for that DC/DC converter. The DC/AC Inverter Control System block110receives the DC bus voltage (vBus), grid voltage (vg), grid current (ig) from the grid and generates the gate pulses for the DC/AC inverter30. Each DC/DC converter control system block has a structure as illustrated inFIG.4. Referring toFIG.4, as can be seen, each DC/DC converter control system block100includes a Voltage Sliding Controller200and a Modulator210. The Voltage Sliding Controller200receives the input voltage (vdcn) and current (idcn) of the respective DC/DC converter being controller and generates the duty cycle (d) and the switching frequency (fsw) of the gate pulses of that DC/DC converter being controlled. The Modulator210receives the duty cycle (d) and the switching frequency (fsw) from the voltage sliding controller200and generates appropriate gate pulses for the DC/DC converter being controlled. Referring toFIG.5, the Voltage Sliding Controller200according to one aspect of the invention includes the following blocks:A DC Source Identification Block300. The DC source identification block determines the type of the input DC power source. This block300determines whether the input of the DC/DC converter controlled is connected to a PV panel (or a suitable renewable energy source) or an energy storage unit. In one implementation, if the DC energy source is identified as a PV Panel this block will generate “1” and if the DC energy source is identified as an energy storage device, the block300it will generate “0”.A Multiplexer310selects between the MPPT Algorithm Block320or the Charge-Discharge Control Block330. The multiplexer310receives the output of the DC source identification block300and, if M=‘1’, the MPPT Algorithm block320is enabled and if M=‘0’ the Charge-Discharge Control is enabled.An MPPT algorithm block320that performs/executes a maximum power point tracking process if the input DC source is identified as a PV panel or a suitable renewable energy source. This block320searches for the maximum power point, where the maximum power can be harvested/received from the PV panel. This block320produces the reference value for the input voltage (Vdc*) or the input current (Idc*) if the input DC source/energy source is identified as a PV panel/renewable energy source. A Charge/Discharge Control block330. This block330controls the charge and discharge of the energy storage if the input DC source/energy source is identified as an energy storage device. This block330produces the reference value for the input voltage (Vdc*) or the input current (Idc*) if the input DC source is identified as an energy storage device.A DC/DC Controller340that receives the output of the multiplexer310. The controller340receives the input voltage (Vdc*) or the input current (Idc*), and the initial duty cycle (d0). The controller340then generates the duty cycle (d) and the switching frequency (fsw) for the DC/DC converter that is being controlled by the DC/DC converter control system block. Referring toFIG.6, illustrated is a flowchart of the process executed by the DC Source Identification Block300. As can be seen from the flowchart, the process begins at step400, that of measuring the input voltage when all the switches are off (open circuit voltage, Voc). Then, a predefined duty cycle (d0) is applied (step410) and the input voltage (Vdc) is measured accordingly (step420). Decision430then combines determining the difference between the open circuit voltage and the input voltage and determining how the difference compares to a predetermined threshold. If the open circuit voltage subtracted from this voltage (Voc−Vdc) is higher than the predefined/predetermined threshold (Vth), then the output from the MPPT block320is used (step440) as the energy source input is identified as a PV panel/renewable energy source. On the other hand, if the difference is equal to or lower than the predefined threshold, then step450is that of enabling the output from the charge/discharge control block330as the energy source is identified as an energy storage device. Step460is then of checking if the system is configured for a reset—if a reset is not detected, then the logic loops back to either step440or step450as show. If a reset is detected, then the logic loops back to step400. Referring toFIG.6, the block diagram of the Inverter Control System is illustrated. In single-phase systems and in unbalanced three-phase systems, there may be a significant amount of double frequency voltage ripple across the DC bus capacitor. Due to the double frequency ripple present at the DC-bus, the bandwidth of the DC bus voltage controller must be limited, otherwise the grid current waveform will have a significant amount of harmonics. In the present invention, the Fast Energy Transfer Controller Block500is used to address this problem. This block500adds an additional term (IgFET) to the output of the low-bandwidth PI (LBW PI) controller510. The additional term (IgFET) is calculated based on the input power (input power: Σ(vdcidc)=Pin) and the DC bus voltage (vBus), and the peak of the grid voltage ({circumflex over (v)}g) as follows: IgFET=[2∑(vdcidc)-2E.]/v^gE=L2CBusvBus2 It should be clear that the various aspects of the present invention may be implemented as software modules in an overall software system. As such, the present invention may thus take the form of computer executable instructions that, when executed, implements various software modules with predefined functions. It should be clear that the various modules of the present invention may be implemented as ASIC (application specific integrated circuits) or as a specifically programmed microcontroller. The present invention may also be implemented using other technologies such as FPGA and DSP. Other implementations, which may use different discrete modules that, when combined, perform the functions detailed above, are also possible. It should also be clear that the energy storage device may be a battery, a supercapacitor, or any other device that stores energy. The renewable energy source may be a PV panel as illustrated or it may be any energy source that produces DC power and is renewable and may be based on wind, solar energy, or any other natural potential power source. As an alternative to the multiplexer in the system, the system may operate to enable/disable specific blocks instead of passing data/signals by way of the multiplexer. It should also be clear that the present invention may use any form of MPPT processes that are known. As examples, perturb, perturb and observe, enhanced perturb and observe or any such similar variants/embodiments of MPPT processes may be used. Embodiments or portions of the invention may be executed by a computer processor or similar device programmed in the manner of method steps, or may be executed by an electronic system which is provided with means for executing these steps. Similarly, an electronic memory means such as computer diskettes, CD-ROMs, Random Access Memory (RAM), Read Only Memory (ROM) or similar computer software storage media known in the art, may be programmed to execute such method steps. As well, electronic signals representing these method steps may also be transmitted via a communication network. Embodiments of the invention may be implemented in any conventional computer programming language. For example, preferred embodiments may be implemented in a procedural programming language (e.g., “C” or “Go”) or an object-oriented language (e.g., “C++”, “java”, “PHP”, “PYTHON” or “C #”). Alternative embodiments of the invention may be implemented as pre-programmed hardware elements, other related components, or as a combination of hardware and software components. Embodiments can be implemented as a computer program product for use with a computer system. Such implementations may include a series of computer instructions fixed either on a tangible medium, such as a computer readable medium (e.g., a diskette, CD-ROM, ROM, or fixed disk) or transmittable to a computer system, via a modem or other interface device, such as a communications adapter connected to a network over a medium. The medium may be either a tangible medium (e.g., optical or electrical communications lines) or a medium implemented with wireless techniques (e.g., microwave, infrared or other transmission techniques). The series of computer instructions embodies all or part of the functionality previously described herein. Those skilled in the art should appreciate that such computer instructions can be written in a number of programming languages for use with many computer architectures or operating systems. Furthermore, such instructions may be stored in any memory device, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies. It is expected that such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (e.g., shrink-wrapped software), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server over a network (e.g., the Internet or World Wide Web). Of course, some embodiments of the invention may be implemented as a combination of both software (e.g., a computer program product) and hardware. Still other embodiments of the invention may be implemented as entirely hardware, or entirely software (e.g., a computer program product). A person understanding this invention may now conceive of alternative structures and embodiments or variations of the above all of which are intended to fall within the scope of the invention as defined in the claims that follow. | 11,815 |
11863012 | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the Drawings.FIG.1shows a system structure diagram of a power supply system1according to an embodiment of the present invention. A power supply system1includes a main battery MB, a sub-battery SB, a first area A1, a second area A2, a third area A3, a fourth area A4, a DC/DC converter2, general loads3and4, BMS5, and a control unit6. The main battery MB is formed e.g. from a lead-acid battery configured to provide a 12V DC voltage. The main battery MB supplies the general load3as well as the first to fourth areas with power via a power supply line MPL. Further, the main battery MB is charged from a power supply system of a high-voltage system (HV) via the DC/DC converter2. This means that the main battery MB functions as a first power supply section which supplies power. The sub-battery SB is formed e.g. from a lead-acid battery configured to provide a 12V DC voltage, and/or a lithium-ion or nickel-hydrogen battery which can be connected to the lead-acid battery. The sub-battery SB supplies the general load4as well as the first to fourth areas with power via a power supply line SPL. This means that the sub-battery SB functions as a second power supply section which supplies power, wherein the second power supply section separate from the main battery MB (first power supply section). The first area A1is one of areas (power supply areas) which are obtained by dividing (sectioning) the power supply system1. The first area A1includes a switching box SW1, ECUs11and12, and loads21and22. The switching box SW1switches an on/off state of power supply from the main battery MB and an on/off state of power supply from the sub-battery SB. A configuration of the switching box SW1is shown inFIG.2. Namely, the switching box SW1functions as one of switching sections each of which is provided in each of a plurality of power supply areas, the plurality of power supply areas being configured to be supplied with power from the main battery MB (first power supply section) and the sub-battery SB (second power supply section), wherein each of the switching sections is configured to switch an on/off state of power supply from the main battery MB (first power supply section) into a corresponding power supply area of the plurality of power supply areas and to switch an on/off state of power supply from the sub-battery SB (second power supply section) into the corresponding power supply area. The wording “corresponding power supply area” refers to an area itself in which the switching box is arranged, wherein for the switching box SW1, the “corresponding power supply area” is the first area, for example. The switching box SW1includes a main-side current meter I1, a sub-side current meter I2, a load voltage meter V0, a main-side voltage meter V1, a sub-side voltage meter V2, switches S1and S2, an MCU31, main-side connection terminals32and33, sub-side connection terminals34and35, a control line connection terminal36, and a load connection terminal37. The main-side current meter I1is arranged between the main-side connection terminals32and33and the switch S1. The main-side current meter I1monitors (detects) a value of current which flows to the switch S1from the power supply line MPL connected to the main-side connection terminal32or main-side connection terminal33. This means that the main-side current meter I1functions as a first current detecting section which detects a first current value which is a value of a current flowing from a side of the main battery MB (first power supply section) in the switching boxes SW1to SW4(switching sections). The sub-side current meter I2is arranged between the sub-side connection terminals34and35and the switch S2. The sub-side current meter I2monitors (detects) a value of current which flows to the switch S2from the power supply line SPL connected to the sub-side connection terminal34or sub-side connection terminal35. This means that the sub-side current meter I2functions as a second current detecting section which detects a second current value which is a value of a current flowing from a side of the sub-battery SB (second power supply section) in the switching boxes SW1to SW4(switching sections). It is to be noted that it is sufficient to configure the main-side current meter I1and/or the sub-side current meter I2from well-known current sensors, such as resistive and/or magnetic current sensors. The load voltage meter V0is arranged between a node between the switch S1and the switch S2and the load connection terminal37. The load voltage meter V0monitors (detects) a value of voltage which is applied to the load (ECU11,12, loads21,22). The main-side voltage meter V1is arranged between the main-side connection terminals32and33and the main-side current meter I1. The main-side voltage meter V1monitors (detects) a value of voltage which is applied to the switch S1. This means that the main-side voltage meter V1functions as a first voltage detecting section configured to detect a first voltage value which is a value of a voltage on the side of the main battery MB (first power supply section) in the switching boxes SW1to SW4(switching sections). The sub-side voltage meter V2is arranged between the sub-side connection terminals34and35and the sub-side current meter I2. The sub-side voltage meter V2monitors (detects) a value of voltage which is applied to the switch S2. This means that the sub-side voltage meter V2functions as a second voltage detecting section configured to detect a second voltage value which is a value of a voltage on the side of the sub-battery SB (second power supply section) in the switching boxes SW1to SW4(switching sections). It is to be noted that it is sufficient to configure the main-side voltage meter V1and the sub-side voltage meter V2e.g. from a well-known voltage detection circuit, such as a resistor, which is arranged between an associated wiring and a ground. The switch S1is arranged between the main-side current meter I1and the switch S2and configured as a switch which switches a conducting state to the loads and the switch S2. The switch S1is configured with a mechanical relay or a semiconductor switch, such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). This means that the switch S1functions as a first switch which is configured to switch the on/off state of the power supply from the main battery MB (first power supply section). The switch S2is arranged between the sub-side current meter I2and the switch S1and configured as a switch which switches a conducting state to the loads and the switch S1. Similarly to the switch S1, the switch S2is configured with a mechanical relay or a semiconductor switch, such as a MOSFET. This means that the switch S2functions as a second switch which is configured to switch the on/off state of the power supply from the sub-battery MB (second power supply section). Further, the switch S1(first switch) and switch S2(second switch) are such that power supply to load is initiated by switching on one of the switches, wherein the load is provided in the power supply area, as evident fromFIGS.1and2. The MCU31is a microcontroller unit including a control circuit such as a CPU (Central Processing Unit), wherein the MCU31performs switching control of the on/off state of the switch S1and switch S2based on a control signal which is outputted by the control unit6via a control line CL. Furthermore, the MCU31provides detected values of the current meters I1and I2and voltage meters V0, V1and V2to the control unit6via the control line CL. The main-side connection terminals32and33are configured as connection terminals for connecting the power supply line MPL thereto. The main battery MB is electrically connected to the main-side connection terminals32and33directly or via another switching box. For example, in the case ofFIG.1, the main battery MB is connected directly to the main-side connection terminal32of the switching box SW1, wherein a switching box SW2and a switching box SW2as other switching boxes are connected to the main-side connection terminal33of the switching box SW1. The sub-side connection terminals34and35are configured as connection terminals for connecting the power supply line SPL thereto. The sub-battery SB is electrically connected to the sub-side connection terminals34and35directly or via another switching box. For example, in the case ofFIG.1, the sub-battery SB is connected directly to the sub-side connection terminal34of the switching box SW3, wherein the switching box SW1and a switching box SW4as other switching boxes are connected to the sub-side connection terminal35of the switching box SW3. The control line connection terminal36is configured for connecting the control line CL thereto, wherein the control line CL serves for inputting/outputting e.g. signals of the control unit6and the MCU31. The load connection terminal37is configured for connecting the loads (ECU11,12) thereto. Returning to the description ofFIG.1, the ECU11is configured as a well-known electronic control unit installed in a vehicle such as an automobile, wherein the ECU11controls the load21. The ECU12is configured as a well-known electronic control unit installed in the vehicle such as an automobile, wherein the ECU12controls the load22. Basically, the second to fourth areas A2to A4are configured in the same manner as the first area A1. The switching boxes SW2to SW4which are arranged in the respective areas are also configured in the same manner as the switching box SW1as shown inFIG.2. Of course, the switching boxes SW2to SW4function as switching sections similarly. As shown inFIG.1, the power supply line MPL from the main battery MB is connected to the switching box SW2and switching box SW3via the switching box SW1and connected to the switching box SW4via the switching box SW2. Furthermore, the power supply line SPL from the sub-battery SB is connected to the switching box SW1and switching box SW4via the switching box SW3and connected to the switching box SW2via the switching box SW4. The DC/DC converter2has a voltage reducing function which reduces a DC voltage received from the high-voltage system and provides it to the main battery MB. Further, the DC/DC converter2may have a voltage increasing function which increases the DC voltage received from the main battery MB and provides it to the high-voltage system. The general load3is a load which is operated with power supplied by the main battery MB. The general load4is a load which is operated with power supplied by the sub-battery SB. Unlike loads21to28, the general loads3and4indicate loads which do not need redundancy. The BMS5is a battery management system and configured as a well-known system (circuit) which monitors and controls a state of a cell(s) of the sub-battery SB. The control unit6controls the switching boxes SW1to SW4arranged in the first to fourth areas A1to A4. The control unit6is configured with a microcontroller for example, which includes e.g. a CPU. This means that the control unit6functions as a control section which performs switching control of the on/off state of the power supply into the power supply areas from the main battery MB (first power supply section) and the on/off state of the power supply into the power supply areas from the sub-battery SB (second power supply section) for the switching boxes SW1to SW4(switching sections). Next, a principal operation of the above-described power supply system1will be described with reference toFIG.3.FIG.3shows views for explaining operation of the main battery MB, sub-battery SB and switching box SW1in the case of a normal state and a state in which an earth fault exists. For better understanding,FIG.3shows only the main battery MB, sub-battery SB, switching box SW1, DC/DC converter2and a LOAD. The LOAD is an ECU11, a load21and/or other, for example. Although the following description inFIG.3will be made with reference to the switching box SW1, the switching boxes SW2to SW4are operated in the same manner. FIG.3shows a normal state in (a). As used herein, the term “normal state” refers to a state in which all current and voltage values fulfill the following formulae (1) to (4), wherein the switch S1and switch S2are switched on in this state. In the formulae (1) to (4), i1indicates a current value (first current value) detected at the main-side current meter I1, i2indicates a current value (second current value) detected at the sub-side current meter I2, v1indicates a voltage value (first voltage value) detected at the main-side voltage meter V1, v2indicates a voltage value (second voltage value) detected at the sub-side voltage meter V2, and v0indicates a voltage value detected at the load voltage meter V0. Furthermore, OC indicates an overcurrent detecting level, LV indicates a voltage drop detecting level, wherein the overcurrent and voltage drop detecting level have predetermined values respectively. −OC≤i1<OC(1) −OC≤i2<OC(2) v1≥v2>LV(3) v0>LV(4) The power supply system1as shown inFIG.1is provided such that in the normal state, a power supply path from the main battery MB and a power supply path from the sub-battery SB are electrically connected to each other by switching on both of the switch S1and the switch S2, so that the load (LOAD) is supplied with power from the main battery MB and the sub-battery SB is charged from the main battery MB. Accordingly, current I flows from the main battery MB toward the load and sub-battery (FIG.3(a)). Here, assuming that an earth fault occurs on the power supply line MPL between the main battery MB and the switching box SW1(FIG.3(b)), the current value i1detected at the main-side current meter I1in such a state indicates an overcurrent in a direction opposite to that in the normal state (−OC>i1), and/or the voltage value v1detected at the main-side voltage meter V1indicates a voltage drop to a level equal to or below the voltage drop detecting level (v1≤LV). In this case, it is determined that a power supply failure exists, wherein the switch S1is switched off in order to stabilize power supply to the load (FIG.3(c)). Once the switch S1is switched off, current flow is blocked from the sub-battery SB to a side of the main battery MB so that the current I flows toward the load. Next, an example for the power supply failure in the power supply system1as shown inFIG.1will be described with reference toFIGS.4and5.FIG.4shows a schematic view of the power supply system1in the normal state (without power supply failure). For better understanding,FIGS.4and5show more simplified views of the power supply system1thanFIG.1. Since the normal state exists inFIG.4, the current I flows from the main battery MB to the sub-battery SB as described above. In this case, the current I also flows from the switching box SW1to the switching box SW4. FIG.5shows schematic views of the power supply system1with power supply failure. These views ofFIG.5show eight patterns. The first view shows a case where an earth fault exists on the power supply line MPL between the main battery MB and the switching box SW1(FIG.5(1)). The second view shows a case where an earth fault exists on the power supply line SPL between the sub-battery SB and the switching box SW3(FIG.5(2)). The third view shows a case where an earth fault exists on the power supply line MPL between the switching box SW1and the switching box SW2(FIG.5(3)). The fourth view shows a case where an earth fault exists on the power supply line SPL between the switching box SW3and the switching box SW4(FIG.5(4)). The fifth view shows a case where an earth fault exists on the power supply line MPL between the switching box SW1and the switching box SW3(FIG.5(5)). The sixth view shows a case where an earth fault exists on the power supply line SPL between the switching box SW1and the switching box SW3(FIG.5(6)). The seventh view shows a case where an earth fault exists on the power supply line MPL between the switching box SW2and the switching box SW4(FIG.5(7)). The eighth view shows a case where an earth fault exists on the power supply line SPL between the switching box SW2and the switching box SW4(FIG.5(8)). A method for detecting the power supply failure states as shown inFIG.5is illustrated in tables ofFIG.6. InFIG.6, (a) shows detected states at the respective boxes and corresponding determinations by the control unit6for the various power supply failure states according to (1) to (8) inFIG.5. InFIG.6, (b) shows control of switching on/off the switches S1and S2in each of the switching boxes for each of the detected power supply failure states. First, in the case of (1) inFIG.5, an earth fault exists on the power supply line MPL between the main battery MB and the switching box SW1so that i1≤−OC for the current value i1detected at the main-side current meter I1, or v1≤LV for the voltage value v1detected at the main-side voltage meter V1in the switching box SW1. This is also the case for the switching boxes SW2to SW4. This exhibits a power supply failure state as described inFIG.3so that it is determined in the control unit6that the main-side voltage has dropped (FIG.6(a), Failure1). After Failure1according to (a) inFIG.6has been determined, the control unit6switches off the switches S1in the switching boxes SW1to SW4. The switches S2remains in an on-state (FIG.6(b), Failure1). In this manner, the current I flows into the switching boxes SW1to SW4from the sub-battery SB as shown in (1) ofFIG.5so that power supply to the load can be stabilized. In the case of (2) inFIG.5, an earth fault exists on the power supply line SPL between the sub-battery SB and the switching box SW3so that i2≤−OC for the current value i2detected at the sub-side current meter I2, or v2≤LV for the voltage value v2detected at the sub-side voltage meter V2in the switching box SW1. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the sub-side voltage has dropped (FIG.6(a), Failure2). After Failure2according to (a) inFIG.6has been determined, the control unit6switches off the switches S2in the switching boxes SW1to SW4. The switches S1remains in an on-state (FIG.6(b), Failure2). In this manner, the current I flows into the switching boxes SW1to SW4from the main battery MB as shown in (2) ofFIG.5so that power supply to the load can be stabilized. In the case of (3) inFIG.5, an earth fault exists on the power supply line MPL between the switching box SW1and the switching box SW2so that in the switching box SW1, i1≤−OC for the current value i1or v1≤LV for the voltage value v1. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the main-side voltage has dropped (FIG.6(a), Failure3). After Failure3according to (a) inFIG.6has been determined, the control unit6switches off the switches S1in the switching boxes SW1to SW4. The switches S2remains in an on-state (FIG.6(b), Failure3). In this manner, the current I flows into the switching boxes SW1to SW4from the sub-battery SB as shown in (3) ofFIG.5so that power supply to the load can be stabilized. In the case of (4) inFIG.5, an earth fault exists on the power supply line SPL between the switching box SW3and the switching box SW4so that in the switching box SW1, i2≤−OC for the current value i2or v2≤LV for the voltage value v2. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the sub-side voltage has dropped (FIG.6(a), Failure4). After Failure4according to (a) inFIG.6has been determined, the control unit6switches off the switches S2in the switching boxes SW1to SW4. The switches S1remains in an on-state (FIG.6(b), Failure4). In this manner, the current I flows into the switching boxes SW1to SW4from the main battery MB as shown in (4) ofFIG.5so that power supply to the load can be stabilized. In the case of (5) inFIG.5, an earth fault exists on the power supply line MPL between the switching box SW1and the switching box SW3so that in the switching box SW1, i1≤−OC for the current value i1or v1≤LV for the voltage value v1. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the main-side voltage has dropped (FIG.6(a), Failure5). After Failure5according to (a) inFIG.6has been determined, the control unit6switches off the switches S1in the switching boxes SW1to SW4. The switches S2remains in an on-state (FIG.6(b), Failure5). In this manner, the current I flows into the switching boxes SW1to SW4from the sub-battery SB as shown in (5) ofFIG.5so that power supply to the load can be stabilized. In the case of (6) inFIG.5, an earth fault exists on the power supply line SPL between the switching box SW1and the switching box SW3so that in the switching box SW1, i2≤−OC for the current value i2or v2≤LV for the voltage value v2. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the sub-side voltage has dropped (FIG.6(a), Failure6). After Failure6according to (a) inFIG.6has been determined, the control unit6switches off the switches S2in the switching boxes SW1to SW4. The switches S1remains in an on-state (FIG.6(b), Failure6). In this manner, the current I flows into the switching boxes SW1to SW4from the main battery MB as shown in (6) ofFIG.5so that power supply to the load can be stabilized. In the case of (7) inFIG.5, an earth fault exists on the power supply line MPL between the switching box SW2and the switching box SW4so that in the switching box SW1, i1≤−OC for the current value i1or v1≤LV for the voltage value v1. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the main-side voltage has dropped (FIG.6(a), Failure7). After Failure7according to (a) inFIG.6has been determined, the control unit6switches off the switches S1in the switching boxes SW1to SW4. The switches S2remains in an on-state (FIG.6(b), Failure7). In this manner, the current I flows into the switching boxes SW1to SW4from the sub-battery SB as shown in (7) ofFIG.5so that power supply to the load can be stabilized. In the case of (8) inFIG.5, an earth fault exists on the power supply line SPL between the switching box SW2and the switching box SW4so that in the switching box SW1, i2≤−OC for the current value i2or v2≤LV for the voltage value v2. This is also the case for the switching boxes SW2to SW4. This exhibits the power supply failure state as described inFIG.3so that it is determined in the control unit6that the sub-side voltage has dropped (FIG.6(a), Failure8). After Failure8according to (a) inFIG.6has been determined, the control unit6switches off the switches S2in the switching boxes SW1to SW4. The switches S1remains in an on-state (FIG.6(b), Failure8). In this manner, the current I flows into the switching boxes SW1to SW4from the main battery MB as shown in (8) ofFIG.5so that power supply to the load can be stabilized. For the failures as described above, if a drop in the main-side voltage or in the sub-side voltage were detected when I1<0 A and/or I2<0 A, a misdetection might occur in the case of a potential temporary power supply to a main-side load and/or in the case of charging the sub-battery SB. Therefore, by comparison with the overcurrent detecting level OC (−OC), it is ensured that power supply failures can be determined. Next, operation in the control unit6as described above will be described with reference to a flowchart inFIG.7. First, the switches S1and switches S2of the switching boxes SW1to SW4are all switched on (step S11). Next, a variable n is set to “0” (step S12). A value of this variable n may be held e.g. in a memory inside the control unit6. Then, “1” is added to the variable n (step S13). The above-mentioned memory or the like is overwritten with the added value. This variable n corresponds to number parts of the reference signs SW1to SW4, wherein the following steps are instructions and determination for one switching box, except for steps S17, S19and S20. Next, the current values in the switching box are measured (step S14). Specifically, a control signal or the like is provided to the control line CL to cause the MCU31in the switching box (SW1when n=1) to measure the current values i1and i2and to transmit measurement results (detection results). Next, the voltage values in the switching box are measured (step S15). Specifically, a control signal or the like is provided to the control line CL to cause the MCU31in the switching box (SW1when n=1) to measure the voltage values v0, v1and v2and to transmit measurement results (detection results). The voltage value v0refers to a voltage value detected at the load voltage meter V0. It is to be noted that the steps S14and S15may be interchanged in the sequence. Next, for the current values and voltage values measured in steps S14and S15, it is determined whether or not the condition is fulfilled that the current value i1>−OC or the voltage value v1>LV (step S16). If the determination in step S16shows that the condition is not fulfilled (step S16; N), the power supply failure state as described inFIG.3exists. Thus, it is determined as a main-side power supply failure, and the switches S1of the switching boxes SW1to SW4are all switched off (step S17). If the determination in step S16shows that the condition is fulfilled (step S16; Y), it is determined whether or not the condition is fulfilled that the current value i2>−OC or the voltage value v2>LV (step S18). If the determination in step S18shows that the condition is not fulfilled (step S18; N), the power supply failure state as described inFIG.3exists. Thus, it is determined as a sub-side power supply failure, and the switches S2of the switching boxes SW1to SW4are all switched off (step S19). If the determination in step S18shows that the condition is fulfilled (step S18; Y), it is determined that there is no abnormality (normal state), and it is determined whether the variable n is “4” or not (step S20). If the variable n is not “4” (step S20, N), the process returns to step S13, wherein “1” is added to the variable n, and the measurement and determination are performed for a next switching box. On the other hand, if the variable n is “4” (step S20; Y), the flowchart is ended. As described above, the control unit6(control section) controls the switching boxes SW1to SW4(switching sections) based on the current value i1(first current value), voltage value v1(first voltage value), current value i2(second current value) and voltage value v2(second voltage value). Further, the control unit6(control section) detects a power supply failure based on the current value i1, voltage value v1, current value i2and voltage value v2. Then, if a power supply failure exists on the side of the main battery MB (first power supply section), power supply from the side of the main battery MB (first power supply section) is switched off, while if a power supply failure exists on the side of the sub-battery SB (second power supply section), power supply from the side of the sub-battery SB (second power supply section) is switched off. Although in the above description, both of the current and voltage values are used for detection of power supply failure, it is to be noted that the detection of power supply failure may be performed by using only the current values, or by using only the voltage values. For example, referring to the flowchart ofFIG.7, only either step S14or step S15may be performed, wherein in steps S16and S17, only either the current values or the voltage values may be used for the determination. The same applied toFIG.6. FIG.8shows a table showing on/off states of switches S1and S2depending on a state of a vehicle. First, when the vehicle is parked, the switch S1is switched on and the switch S2is switched off. This is aimed at preventing discharge of the sub-battery SB, i.e., power consumption of the sub-battery SB due to dark current. The detection of parking may be accomplished via a well-known method, such as detection of ignition-off. In the normal state, such as driving or regenerative operation, both of the switches S1and S2are switched on. In this state, the sub-battery SB is charged in addition to power supply to the load, as described above. In the case of restart, the switch S1is switched off, while the switch S2is switched on. This means that when restarting an engine e.g. in a hybrid vehicle, the switch S1is temporarily switched off and power supply is thus performed from the sub-battery SB, which prevents voltage fluctuation in each of the areas and always enables stable power supply. In the case of the main-side voltage drop or earth fault, the switch S1is switched off and the switch S2is switched on as a backup control, as described above. In the case of sub-side voltage drop or earth fault, the switch S1is switched on and the switch S2is switched off as a backup control, as described above. FIG.9shows an example for a timing diagram illustrating operation of the above-described power supply system1. This Figure shows the cases of (1) inFIG.5/Failure1inFIG.6and (2) inFIG.5/Failure2inFIG.6. It is to be noted that operation for (3), (5) and (7) inFIG.5/Failures3,5and7is configured in a similar manner as operation for (1) inFIG.5/Failure1inFIG.6, wherein operation for (4), (6) and (8) inFIG.5/Failures4,6and8inFIG.6is configured in a similar manner as operation for (2) inFIG.5/Failure2inFIG.6. InFIG.9, IG indicates ignition, DC/DC OUTPUT indicates output of the DC/DC converter2, SW1-V1indicates the voltage value v1of the voltage meter V1in the switching box SW1, SW1-V2indicates the voltage value v2of the voltage meter V2in the switching box SW1, SW1-I1indicates the current value i1of the current meter I1in the switching box SW1, SW1-I2indicates the current value i2of the current meter I2in the switching box SW1, SW1-S1indicates the switch S1in the switching box SW1, and SW1-S2indicates the switch S2in the switching box SW1. SW2-S1indicates the switch S1in the switching box SW2, SW2-S2indicates the switch S2in the switching box SW2, SW3-S1indicates the switch S1in the switching box SW3, SW3-S2indicates the switch S2in the switching box SW3, SW4-S1indicates the switch S1in the switching box SW4, and SW4-S2indicates the switch S2in the switching box SW4. InFIG.9, an initial state exists first in which the switch S1is switched on and the switch S2is switched off (see parking inFIG.8). Then, if the ignition turns on (IG ON) at time t1, the control unit6switches the switch S2on (see the normal state inFIG.8). Then, if a power supply failure occurs on the main-side at time t2, the DC/DC converter2starts to reduce a voltage of its output. This is accompanied by SW1-V1and SW1-V2starting to reduce their voltage values, wherein SW1-I1also starts to reduce its current value. On the other hand, SW1-I2starts to increase its current value. Then, SW1-V1is reduced to the voltage drop detecting level LV or smaller at time t3, and SW1-I1is reduced to —OC or smaller (SW1-I2is equal to or larger than OC). Therefore, the power supply failure state as described inFIG.3exists so that the control unit6switches the switch S1off. The switch S2remains in an on-state. If a power supply failure occurs on the sub-side at time t4(after time t1), the DC/DC converter2starts to reduce a voltage of its output. This is accompanied by SW1-V1and SW1-V2starting to reduce their voltage values, wherein SW1-I2also starts to reduce its current value. On the other hand, SW1-I1starts to increase its current value. Then, SW1-V2is reduced to the voltage drop detecting level LV or smaller at time t5, and SW1-I2is reduced to —OC or smaller (SW1-I1is equal to or larger than OC). Therefore, the power supply failure state as described inFIG.3exists so that the control unit6switches the switch S2off. The switch S1remains in an on-state. FIGS.10to12show other examples for wiring arrangement of the power supply line MPL and the power supply line SPL.FIG.10shows a ring-shaped wiring arrangement of the power supply line MPL for the switching boxes SW1to SW4. The wiring of the power supply line SPL is arranged in the same manner asFIG.1.FIG.11shows a ring-shaped wiring arrangement of the power supply line MPL as shown inFIG.10, wherein for the power supply line SPL, the wiring is arranged to connect the switching boxes SW1to SW4directly to the sub-battery (also referred to as “bus-shaped”).FIG.12shows ring-shaped wiring arrangements of both of the power supply lines MPL and SPL for the switching boxes SW1to SW4. As shown above, the wiring of the power supply line MPL and power supply line SPL may be arranged in various shapes, wherein different wiring configurations may be used for the power supply line MPL and the power supply line SPL. As shown inFIGS.1and10to12, the switching boxes SW1to SW4(switching sections) are connected directly to at least one of the main battery MB (first power supply section) and the sub-battery SB (second power supply section). Furthermore, the switching boxes SW1to SW4(switching sections) are connected to at least one of the main battery MB (first power supply section) and the sub-battery SB (second power supply section) via another switching box(es) (switching section). This means that the wiring from the main battery MB to the switching boxes SW1to SW4in the first to fourth areas A1to A4may extend along a different path from that of the wiring from the sub-battery SB to the switching boxes SW1to SW4in the first to fourth areas A1to A4, so that it is possible to avoid simultaneous power supply failures for the main battery MB and the sub-battery SB. FIG.13shows an exemplar variation of the switching box. In the structure as shown inFIG.2, redundancy of power supply is not possible when power supply failures simultaneously occur at two points on the wiring paths of the power supply line MPL and the power supply line SPL between the switching boxes (seeFIG.14). A switching box SW1A according toFIG.13is configured by removing the voltage meters V1and V2from the structure ofFIG.2and by adding switches S11, S12, S21, S22as well as voltage meters V11, V12, V21, V22to the structure ofFIG.2. The switch S11is arranged between the main-side connection terminal32and the current meter I1. The switch S12is arranged between the main-side connection terminal33and the current meter I1. The switch S11and switch S12are connected in series. The switch S21is arranged between the sub-side connection terminal34and the current meter I2. The switch S22is arranged between the sub-side connection terminal35and the current meter I2. The switch S21and switch S22are connected in series. This means that the switch S11functions as a third switch (or fourth switch) arranged on a side of the main battery MB (first power supply section) with respect to the first switch, wherein the switch S12functions as a fourth switch (or third switch) arranged on the side of the main battery MB (first power supply section) with respect to the first switch. The switch S21functions as a fifth switch (or sixth switch) arranged on a side of the sub-battery SB (second power supply section) with respect to the second switch, wherein the switch S22functions as a sixth switch (or fifth switch) arranged on a side of the sub-battery SB (second power supply section) with respect to the second switch. The voltage meter V11measures (detects) a voltage applied to the switch S11. The voltage meter V12measures (detects) a voltage applied to the switch S12. The voltage meter V21measures (detects) a voltage applied to the switch S21. The voltage meter V22measures (detects) a voltage applied to the switch S22. The switching box SW1A is configured such that an upstream side (e.g. the main-side connection terminal32side and/or the sub-side connection terminal34side) and a downstream side (e.g. the main-side connection terminal33side and/or the sub-side connection terminal35side) can be completely disconnected from each other via the switches S11, S12, S21and S22. FIG.14shows a schematic view of a power supply system1A with the switching box SW1A according toFIG.13. InFIG.14, the switching boxes SW2A to SW4A are configured in the same manner as the switching box SW1A. In this Figure, (9) shows a case where earth faults exist on both of the power supply line MPL and the power supply line SPL between the switching box SW1A and the switching box SW3A. (10) shows a case where earth faults exist on both of the power supply line MPL and the power supply line SPL between the switching box SW2A and the switching box SW4A. Here, the numbers in brackets inFIG.14are serial numbers following the numbers as used inFIG.5. This means that the two views show the ninth and tenth patterns of power supply failure. FIG.14shows cases where power supply failures simultaneously occur at two points on the power supply line MPL and the power supply line SPL. In these cases, the switching boxes SW1A and SW2A are disconnected (isolated) from the switching boxes SW3A and SW4A by switching the switches S11, S12, S21, S22in the switching boxes SW1A to SW4A in order to ensure redundant paths. Once the redundant paths are ensured in this manner, a current Ia flows from the main battery MB to the switching boxes SW1A and SW4A so that power supply is accomplished to the associated first area A1and second area A2. Further, a current Ib flows from the sub-battery SB to the switching boxes SW3A and SW4A so that power supply is accomplished to the associated third area A3and fourth area A4. In the case where the switching boxes SW1A to SW4A are applied to the ring-shaped wiring arrangements of the power supply lines as shown inFIGS.10to12, it is possible to change the wiring paths so that in the ring for the main battery (power supply line MPL), a power supply failure (earth fault) point(s) can be disconnected (isolated) via the switches S11and S12, wherein in the ring for the sub-battery (power supply line SPL), a power supply failure (earth fault) point(s) can be disconnected (isolated) via the switches S21and S22, which enable power supply redundancy with higher reliability. According to the present embodiment, the power supply system1includes the main battery MB configured to provide power, and the sub-battery SB which is separate from the main battery MB and configured to provide power. The power supply system1further includes the switching boxes SW1A to SW4A arranged in the first to fourth areas A1to A4which are a plurality of power supply areas, the plurality of power supply areas being configured to be supplied with power from the main battery MB and the sub-battery SB, wherein the switching boxes SW1A to SW4A are configured to switch an on/off state of power supply into the first to fourth areas A1to A4from the main battery MB and to switch an on/off state of power supply into the first to fourth areas A1to A4from the sub-battery SB. Furthermore, the power supply system1includes the control unit6configured to perform switching control of the on/off state for the switching boxes SW1A to SW4A. The above configuration of the power supply system1enables the power supply from the main battery MB and the sub-battery SB to be switched on/off with the switching boxes SW1A to SW4A, whereby it is not necessary to provide e.g. a battery for each area and it is enabled with low costs to stabilize power supply voltages of multiple areas and/or to achieve redundancy. Even when an additional area is provided, it is only necessary to add a switching box. Further, each of the switching boxes SW1A to SW4A includes the switch S1and switch S2, wherein the switch S1is configured to switch the on/off state of the power supply from the main battery MB and the switch S2is configured to switch the on/off state of the power supply from the sub-battery SB. In this manner, it is possible to switch the on/off state of the power supply for the main battery MB and the sub-battery SB individually. Therefore, it is possible to achieve an appropriate power supply depending on existence of an earth fault on each of the power supply line MPL for the main battery MB and the power supply line SPL for the sub-battery SB, and/or an operation state of e.g. an equipment in which the power supply system1is installed, such as a vehicle. Furthermore, the switch S1and the switch S2are configured such that power supply to the load is initiated by switching on one of the switch S1and switch S2, wherein the load is provided in the power supply area. In this manner, it is possible to perform power supply from one of the main battery MB and the sub-battery SB, which may enable redundancy of the power supply paths. Furthermore, the switch S1and the switch S2are configured such that the power supply path from the main battery MB and the power supply path from the sub-battery SB are electrically connected by switching on both of the switches S1and S2. This enables the sub-battery SB to be charged from the main battery MB and/or the DC/DC converter2. Moreover, each of the switching boxes SW1A to SW4A includes the switch S11and the switch S12on the side of the main battery MB with respect to the switch S1, as well as the switch S21and the switch S22on the side of the sub-battery SB with respect to the switch S2. In this manner, even when power supply failures occur on the power supply line MPL and the power supply line SPL between the same switching boxes, it is possible to ensure a redundant path while isolating the power supply failure points. Further, the power supply system1includes the current meter I1and current meter I2configured to detect the current value i1of current flowing from the main battery MB and the current value i2of current flowing from the sub-battery SB in the switching boxes SW1A to SW4A, respectively, and the voltage meter V1and voltage meter V2configured to detect the voltage value v1of voltage on the side of the main battery MB and the voltage value v2of voltage on the side of the sub-battery SB in the switching boxes SW1A to SW4A, respectively. In addition, the control unit6is configured to control the switching boxes SW1A to SW4A based on the current value i1and voltage value v1as well as based on the current value i2and the voltage value v2. In this manner, it is possible to detect (determine) existence of power supply failure on the side of the main battery MB based on overcurrent and/or voltage drop on the side of the main battery MB, and it is further possible to detect (determine) existence of power supply failure on the side of the sub-battery SB based on overcurrent and/or voltage drop on the side of the sub-battery SB. Furthermore, the control unit6is configured to detect a power supply failure based on the current value i1and the voltage value v1on the side of the main battery MB as well as based on the current value i2and the voltage value v2on the side of the main battery MB, wherein the control unit6switches the switch S1so as to switch off the power supply from the side of the main battery MB if a power supply failure occurs on the side of the main battery MB, and wherein the control unit6switches the switch S2so as to switch off the power supply from the side of the sub-battery SB if a power supply failure occurs on the side of the sub-battery SB. In this manner, it is possible to detect existence of power supply failure on the side of the main battery MB and existence of power supply failure on the side of the sub-battery SB individually. In addition, the power supply from the main battery MB can be stopped in the case of power supply failure on the side of the main battery MB, and the power supply from the sub-battery SB can be also stopped in the case of power supply failure on the side of the sub-battery SB. Moreover, the wiring from the main battery MB to the switching boxes SW1A to SW4A in the first to fourth areas A1to A4extends along a different path from that of the wiring from the sub-battery SB to the switching boxes SW1A to SW4A in the first to fourth areas A1to A4, so that it is possible to avoid simultaneous power supply failures for the main battery MB and the sub-battery SB. The present invention is not limited to the above-described embodiments. Namely, those skilled in the art may modify and implement the embodiments based on the knowledge in the prior art without departing from the core of the present invention. It should be understood that such modifications fall under the scope of the invention as long as they include the features of the power supply system according to the present invention. REFERENCE SIGNS LIST 1Power supply system6Control unit (control section)MB Main battery (first power supply section)SB Sub-battery (second power supply section)A1-A4First to fourth areas (power supply areas)SW1-SW4Switching boxes (switching sections)I1, I2Current meters (current detecting sections)V1, V2Voltage meters (voltage detecting sections)S1Switch (first switch)S2Switch (second switch)S11Switch (third switch)S12Switch (fourth switch)S21Switch (fifth switch)S22Switch (sixth switch) | 45,826 |
11863013 | DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments. However, it is to be understood that other embodiments may be utilized and that logical, mechanical, and electrical changes may be made. Furthermore, the method presented in the drawing figures and the specification is not to be construed as limiting the order in which the individual steps may be performed. The following detailed description is, therefore, not to be taken in a limiting sense. Embodiments of the present invention provide a capability to externally switch load power from a “primary” power source to a “backup” power source and from a “backup” power source to a “primary” power source without interruption to the operation of the load. In one embodiment, a circuit automatically detects a drop in primary power voltage and switches the load power input to a backup power source when the primary power source falls below a configurable threshold level. In another embodiment, the circuit automatically detects a rise in primary power voltage and switches load power from the backup power source back to the primary power source once the primary power source rises above a different, configurable threshold level. The power switching is completed in a smooth and fast manner such that the load does not experience sufficient voltage drop or current transients that would cause it to cease operating. This switching is accomplished independent of the relative voltage levels of the two power sources provided the backup voltage level is greater than the primary's falling threshold. For pedagogical purposes, this specification generally describes the embodiments being connected to positive input and output voltage levels. It is understood, however, that other embodiments of this invention function in typical telecommunication applications that use negative voltages (e.g., −48V). For embodiments using negative input and load voltages, the terms “fall” or “drop” associated with an input voltage would indicate the voltage is going less negative; the term “rise” associated with a negative input voltage would indicate the voltage is going more negative. In light of this dual embodiment, the voltages levels as discussed in this specification are best viewed as absolute (rather than positive or negative) values. FIG.1is a block diagram of one embodiment of a circuit, indicated generally at100, for switching between a primary power source and a backup power source according to the teachings of the present invention. The circuit100includes two ports for receiving power. Primary power port116is configured to be coupled to a primary power source. Primary power port116has two nodes labelled Primary and Primary return (RTN), respectively. Backup power port120is adapted to be coupled to a backup power source and includes two nodes labelled Backup and Backup RTN, respectively. The circuit100also includes a port that is configured to provide power to a load. Load power port124includes two nodes labelled Load Power and Load RTN. The circuit100includes two paths for providing power to the load. The first (primary) path includes power field effect transistor (FET)105coupled between primary power port116and load power port124. The second path (back-up) includes power field effect transistors (FETs)101and102that are coupled in series between backup power port120and load power port124. Advantageously, use of power transistors provides lower heat dissipation than diodes or mechanical relays used in conventional approaches due to the low inline “on” resistance of the power MOSFETS. Power MOSFETs are also smaller in size than mechanical components that carry equivalent current. Further, embodiments of the present invention provide enhanced reliability and faster response times resulting from using solid state technology rather than mechanical components. The circuit100also includes a control circuit for switching between the primary power source and the backup power source. This control circuit includes microcontroller110, opto-isolator103and dual-ideal-OR controller104. Opto-isolator103is coupled between microcontroller110and a control input of FET101. Microcontroller110provides control signals to turn on and off opto-isolator103as described in more detail below. Opto-isolator103bridges the gap between low voltage electronics in the microcontroller110and the higher voltage regime of the power FETs, e.g., FETs101and102. Dual ideal diode-OR controller104is coupled to FET102and FET105. Controller104alternatively turns on and off the power FETs102and105as described in more detail below. Microcontroller110determines when to switch between the primary power source at primary power port116and the backup power source at backup power port120. The microcontroller110accomplishes this by comparing the voltage of the primary power source at primary power port116against two thresholds, high threshold107and low threshold109, as described in more detail below. In another embodiment, the microcontroller110could be replaced by discrete analog and/or digital logic performing the same functionality. Circuit100also includes voltage and current sensing circuit114. Voltage and current sensing circuit114gathers data on voltage and current in circuit100through current sense elements150,152, and154. Current sense element150measures current from back-up power port120. Current sense element152measures current from primary power port116. Finally, current sense element154measure current at load power port124. Voltage and current sensing can also be used to monitor power and expended energy. Circuit114allows the voltage and current levels of the backup and primary power sources to be monitored by microcontroller110. Communication between voltage and current sensing circuit114and microcontroller110is accomplished by way of a two-wire interface. Communication schemes in other embodiments include Serial Peripheral Interface (SPI), Universal Serial Bus (USB) or circuit114can have analog outputs that connect to an analog to digital converter (ADC) internal to the microcontroller110. In one embodiment, the voltage and current sensing circuit114can be used to detect faults, such as, overvoltage, under voltage, over current, low current, or the like. Low threshold109and high threshold107used by microcontroller110may be adjusted through microcontroller110for a specific implementation. In one embodiment, the high and low voltage thresholds107and109are set by way of a two-wire interface connecting a variable voltage divider to microcontroller110. In another embodiment, the high and low thresholds107and109are set by references106and108respectively. These embodiments for thresholds107and109could be implemented via a discrete reference voltage, a digital potentiometer, stored memory or, for fixed thresholds, a highly precise resistor array. This path provides a mechanism for setting the window to implement hysteresis as discussed in more detail below that prevents switching oscillation and instability. Microcontroller110includes a communication (Comm) port112. Comm Port112provides an interface to an external host that allows for the communication, monitoring and control of the voltages, currents and switching thresholds in circuit100. Comm port112could be used to change switching thresholds107and109, create an alarm when a switching event occurs, or provide feedback about the primary source voltage and current levels. This could be implemented as serial data (e.g., RS-232, RS-485), Ethernet, or discrete digital input/output lines. Advantageously, comm port112enables field site adjustments and real time monitoring of voltage and current levels to an external host not provided by current art. This comm port112allows for remote monitoring of voltage and current levels, e.g. at the base when circuit100is installed at the tower top. Circuit100also includes power converter113. Power converter113converts high voltage levels at, for example, load power port124to one or more lower level voltages needed by microcontroller110and other control functions in circuit100. In other embodiments, power converter113may receive high voltage level input from primary power port116or back-up power port120. In one embodiment, power converter113also includes a battery128that provides power to circuit100when no power is output at load power port124. In this way, power converter113can provide power to microcontroller110and other low voltage circuitry (for example, voltage and current sensing circuit114, high threshold107, low threshold109, reference106, and reference108) from battery128to configure and control circuit100in the absence of inputs at both primary power port116and backup power port120or failure of load port124. In another embodiment, power converter113can also select between power inputs120and116. FIG.2is a flowchart on one embodiment of a method for switching between a primary power source and a backup power source according to the teachings of the present invention. The operation of circuit100will be described in conjunction with the process ofFIG.2. The process ofFIG.2is divided into two paths at block202. At block202, it is determined whether the primary or back up power source is currently providing power for the load. If the primary power source is providing power, the process proceeds to block204to determine if the primary power source needs to be replaced by the backup power source. Otherwise, if the back-up power source is providing power to the load, the process proceeds to block210to determine if the primary power source is back on-line. According to this process, circuit100normally supplies power to the load from the primary source. To accomplish this, microcontroller110turns opto-isolator103off which in turn keeps FET101off, physically disconnecting the backup power source from the load. When circuit100is in this condition as determined at block202, the microcontroller110compares the primary source voltage to a first threshold, e.g., the low threshold109voltage value at block204. This comparison determines whether the primary voltage is present and sufficient to power the load. If the primary power source has not crossed the first threshold, for example, has not dropped below the low threshold, then the process returns to block200and, with the backup source physically disconnected, the dual ideal diode-OR controller104enables FET105to drive power to the load from the primary power source. The process continues to monitor the primary power source at block200. A short, brown-out, other fault condition or deactivation may occur to the primary power source which causes its voltage level to cross the first threshold, e.g., fall below low threshold109. This falling voltage level is detected by microcontroller110at block204and the process proceeds to optional block206. In an alternate embodiment discussed below, a backup power source is shared between N primary power sources. In such an embodiment, the circuit100does not switch to the backup power source if another of the N primary power sources has already been replaced by the backup power source. Thus, the process returns to block200and monitors the primary power source. If however, the backup power source is not in use or the backup is not shared, the process proceeds to block208. The Microcontroller110reacts by turning on opto-isolator103to enable power FET101once the first threshold is crossed, e.g., the voltage drops below the low threshold. Once enabled, power FET101allows voltage to pass to power FET102. Since the backup voltage level will be higher than that of the primary voltage at its low threshold, the dual ideal diode-OR controller104will detect current flowing through the body diode of power FET102and switch load power to the backup by turning off power FET105. It is noted that the design of circuit100has the benefit that the backup voltage can be higher or lower than the primary voltage without being switched to the load when not needed. This is not the case with an ideal diode-OR only solution that simply switches whichever voltage is the highest to the load. This control mechanism provides a number of additional benefits over conventional circuits used to switch between primary and backup power sources. For example, circuit100provides smooth switching between power sources while reducing voltage and current transients. Large energy spikes associated with normal power switching are eliminated. Further, fast switching response time enabled by controller110, opto-isolator103and FET101allows load power to be switched before the primary voltage level drops below the minimum required load voltage. This avoids a power loss to the load that would interrupt load operation. Additionally, embodiments of the invention act as a voltage prioritizer for voltages higher (up to 100V) than current prioritizers (up to 36V). The process returns to block200and monitors the primary power source. Circuit100continues to supply load power from the backup once the primary source crosses the first threshold, e.g., falls below low threshold109until the primary source voltage level crosses a second threshold, e.g., rises above a high threshold107. This technique implements hysteresis such that switching oscillation does not occur from a slow slew rate, noise or transients on the primary voltage as it is falling below low threshold109. The use of programmable switching thresholds with inherent hysteresis facilitates easy and relatively wide adjustable thresholds and hysteresis to accommodate system noise and switching transients. Averaging and digital filtering could also be employed for a more robust hysteresis algorithm. Current art depends on resistor dividers or fixed values for threshold and hysteresis. If the fault condition is cleared from the primary power source or the primary power source is reactivated causing its output voltage to rise, microcontroller110will detect this rising voltage as it crosses high threshold107at block210. Once microcontroller110detects the primary voltage rising above high threshold107, it proceeds to block212and shuts off opto-isolator103which in turn disables power FET101. This effectively disconnects the backup power source to the load once again. Dual diode-OR controller104, sensing current beginning to flow through the body diode of power FET105and current ebbing with voltage dropping and finally reversing in power FET102, will enable power FET105and disable power FET102. Load power has now been shifted back to the primary power source from the backup power source. The process returns to block200and monitors the primary power source. Hysteresis protection against switching oscillation is also implemented once circuit100switches load power back to the primary by preventing another switch to the backup unless the primary voltage level once again falls below low threshold109using the process described above with respect to blocks202,204,206, and208. FIG.3is a block diagram of an embodiment of an electronic system, indicated generally at300, including N circuits (302-1to302-N) that share one backup power source between N loads. Circuits302-1to302-N each switch between their respective primary power source at primary power ports306-1to306-N and a shared backup power source at backup power port304. Advantageously, this embodiment of the invention enables backup switching for multiple, N, loads from a single backup power source or 1:N redundancy. This feature allows the backup power source at backup power port304to be switched to any one of “N” output loads at load power ports308-1to308-N. Since the backup power source typically is insufficient to power multiple loads, the backup power source provides power to only one of the “N” loads at a time. In this embodiment, the switching of a backup source to one and only one of N multiple loads concurrently is accomplished through an “open drain” (drive low only) signaling technique as described below. For 1:N redundancy configurations such as shown inFIG.3, one power selection circuit302is needed per load. In one embodiment, the power selection circuit is implemented using the circuit100ofFIG.1. In a typical embodiment, individual, primary power sources are connected to the primary power ports306-1to306-N of system300. For backup power, the single, backup power port304couples the backup power source to the backup power source inputs of the power selection circuits302. Each power selection circuit302has a 1:N open-drain (OD) control I/O signal that is connected to all the power selection circuits302. The OD control I/O signal is both an input and output of microcontroller110and serves to communicate the state of the backup control logic of the entire system300. The driver for this signal in microcontroller110(FIG.1) can either be disabled (“tri-stated”) or driven low depending upon the state of the backup switch logic for all the individual power selection circuits. This OD control I/O signal is also wired back to microcontroller110as an input for monitoring the state of the OD control I/O signal. Monitoring can be accomplished with control logic implemented internal or external to the microcontroller110. During normal operation, the individual power selection circuits302-1to302-N provide power to their loads from the individual primary power sources coupled to primary power ports306-1to306-N, respectively. The backup source is physically disconnected in each of the power selection circuits302-1to302-N and does not provide power to the power load node308-1to308-N coupled to the respective power selection circuits302-1to302-N as described above. Under these conditions, each power selection circuit302-1to302-N will disable its OD control I/O driver and resistor111will pull this signal to a logic “high” indicating to all power selection circuits302-1to302-N that no individual power selection circuit302-1to302-N has switched to the backup power source. In this redundancy embodiment, power selection circuits302-1to302-N include the optional block206ofFIG.2. The function of block206is governed by the current state of the OD control I/O signal. At block204, if microcontroller110detects the voltage level of the primary source falls below low threshold109, then microcontroller110checks the state of the OD control I/O signal at block206. If it is “high” as described above, microcontroller110not only activates opto-isolator103as described above with respect to block208but also drives its OD control I/O signal low. This communicates to all of the other power selection circuits302that one of the power selection circuits302-1to302-N has switched to use the backup power source. If the state of the OD control I/O signal is low at block206, then microcontroller110is prevented from activating its opto-isolator103at block208that would cause the output load to switch to the backup power source due to the fact that one of the other individual power selection circuits302has already switched its load to the backup power source. Should the primary source voltage level of the redundant system that is switched to backup power rise back above high threshold107(block210), then microcontroller110again “tri-states” the OD control I/O signal (at block212). Resistor111will pull the OD control I/O signal back high allowing any of the power selection circuits302to switch to backup if their primary power source falls below low threshold109. FIG.4is a block diagram of an electronic system, indicated generally at400, that includes a circuit406for selecting between a primary power source402and a backup power source404according to the teachings of the present invention. Circuit406is coupled to load408, for example, telecommunications circuitry such as a remote radio head, remote unit of a distributed antenna system, or other appropriate electronic circuit. Circuit406also includes battery412to provide power to the circuit406to enable configuration and control of circuit406when primary power source402and backup power source404are not available or the output power port to load408has failed. Circuit406also includes comm port410to provide an interface for configuring circuit406in a similar manner to embodiments discussed above. Circuit406is configured to include in-line power switches controlled by low-voltage circuitry and an ideal-OR controller to enable fast, smooth switching to backup power source404when primary power source drops below a configurable threshold. Circuit406implements hysteresis to prevent switching oscillation from a slow slew rate, noise or transients on the primary voltage as it is falling below the threshold. In one embodiment, circuit406is configured as shown and described above with respect toFIG.1. In operation, circuit406selects between primary power source402and backup power source404. When primary power source crosses a first threshold, e.g., drops below a selected voltage, circuit406selects backup power source404and passes this power to load408. When the backup power source404is providing power to load408, circuit406monitors primary power source402to determine when the primary power source402is back on-line. Circuit406determines when the primary power source402crosses a second threshold, e.g., rises above a second selected voltage. When this occurs, circuit406switches back to using primary power source402as the power source for the load408. FIG.5is a block diagram of another embodiment of an electronic system, indicated generally at500, that includes a circuit506for selectively applying one backup power source504in place of one of N primary power sources502-1to502-N to one of N respective to loads508-1to508-N, for example, telecommunications circuitry such as a remote radio head, remote unit in a distributed antenna system or other appropriate electronic circuits. Circuit506also includes battery512to provide power to the circuit506to be used to provide power to circuit506to enable configuration and control of circuit506if load power is unavailable due to power output failure or if primary and backup power sources are not available. Circuit506also includes comm port510to provide an interface for configuring circuit506. In one embodiment, power source selection circuit506is constructed as shown and described above with respect toFIGS.1and3. In operation, circuit506selects between primary power sources502-1to502-N and backup power source504. When one of the primary power sources502-1to502-N crosses a first threshold, e.g., drops below a selected voltage level, circuit506selects backup power source504and passes this power to the corresponding load508. Circuit506also sets a signal that indicates that the backup power source504is currently in use. This signal is used to prevent the backup power source504from being switched to any of the other N loads. When the backup power source504is providing power to one of N loads508-1to508-N, circuit506monitors the primary power source502that was switched out to determine when the primary power source502is back on-line. Circuit506determines when the primary power source502is back online when the power supplied by the primary power source502crosses a second threshold, e.g., rises above a second selected voltage. When this occurs, circuit506switches back to using primary power source502as the power source for the corresponding one of loads508-1to508-N and clears the signal indicating backup power is available. EXAMPLE EMBODIMENTS Example 1 includes a circuit for selecting between a primary power source and a back-up power source. The circuit includes a first port configured to be coupled to a primary power source, a second port configured to be coupled to a back-up power source, a third port configured to be coupled to provide power to a load, first and second power field effect transistors (FET) coupled between the second port and the third port, a third power FET coupled between the first port and the third port, a dual ideal diode-OR controller coupled between the second and third power FETs to selectively turn on and off the second and third power FETs, an opto-isolator coupled to a control input of the first power FET, a controller, coupled to the opto-isolator, that selectively turns on and off the opto-isolator, wherein the controller monitors the power received at the first port and, when the power at the first port crosses a first threshold level, turns on the opto-isolator so that power is transmitted by the first and second power transistors between the second port and the third port and when the power at the first port crosses a second threshold level, turns off the opto-isolator so that power is transmitted by the third power transistor between the first port and the third port. Example 2 includes the circuit of example 1, wherein the controller includes a port that produces a signal that enables the circuit to share the backup power source in a 1:N redundancy arrangement. Example 3 includes the circuit of any of examples 1 and 2, wherein the first and second thresholds have different, configurable values. Example 4 includes the circuit of example 3, wherein the controller turns on the opto-isolator when the power at the first port, as measure by a voltage level at the first port, drops below a low voltage threshold. Example 5 includes the circuit of example 4, wherein the controller turns off the opto-isolator when the power at the first port, as measured by a voltage level at the first port, crosses above a high voltage threshold that is above the low voltage threshold. Example 6 includes the circuit of any of examples 1-5, and further comprising a voltage and current sensing circuit configured to sense at least the voltage or current at at least one of the first, second and third ports. Example 7 includes the circuit of any of examples 1-6, and further comprising a communications port coupled to the controller that is configured to establish the first and second thresholds. Example 8 includes the circuit of any of examples 1-7, and further including at least one of a discrete reference voltage, a digital potentiometer, stored memory or a highly precise resistor array that are configured to establish the first and second thresholds. Example 9 includes the circuit of any of examples 8, and further comprising a power converter that is coupled to receive a high input voltage from at least one of the first, second and third ports and convert the voltage to one or more lower level voltages for use by at least the controller. Example 10 includes the circuit of example 9, wherein the power converter further includes a battery port that is configured to be coupled to a battery to provide power to the controller and other low voltage devices in the absence of a voltage at the first, second and third ports. Example 11 includes a system that includes a load, a primary power port configured to be coupled to a primary power source, a back-up power port configured to be coupled to a back-up power source, a power source selection circuit, coupled to the load and the primary and back-up power ports. The power source selection circuit includes at least one power field effect transistor in a first path between the primary power port and the load, at least two power field effect transistors in a second path between the back-up power port and the load, a voltage and current sensing circuit, and a controller, coupled to one of the power field effect transistors in the first path and the voltage and current sensing circuit, wherein the controller is configured to selectively connect the back-up power source to the load by turning on and off the one of the power field effect transistors in the first path in response to the output of the voltage and current sensing circuit. Example 12 includes the system of example 11, wherein the load comprises one of telecommunications circuitry, a remote radio head, remote unit or other circuitry in a distributed antenna system. Example 13 includes the system of any of examples 11 and 12, and further comprising a dual diode-OR controller configured to selectively turn on and off the at least one power field effect transistor in the first path and the other of the at least two power field effect transistors in the second path. Example 14 includes the system of any of examples 11-13, and further including a communications port coupled to the controller, the communications port configured to receive inputs that establish thresholds used by the controller to determine when to turn on and off the one of the power field effect transistors in the first path. Example 15 includes the system of any of examples 11-14, wherein the load comprises a plurality of loads, the primary power port comprises a plurality of primary power ports, each of the primary power ports associated with a corresponding one of the plurality of loads, and the power source selection circuit selectively connects the back-up power source to one of the plurality of loads in response to a sensed condition of the corresponding primary power source. Example 16 includes a method for selecting a power source for a load. The method includes monitoring the primary power source, when the primary power source is providing power to the load, determining if a condition of the primary power source crosses a first threshold, when the condition crosses the first threshold, turning on a first power field effect transistor to couple a back-up power source to the load through a second power field effect transistor, when the primary power source is not providing power to the load, determining if a condition of the primary power source crosses a second threshold, when the condition crosses the second threshold, switching off the first power field effect transistor to couple the primary power source to the load through a third power field effect transistor. Example 17 includes the method of example 16, wherein monitoring the primary power source comprises monitoring a voltage level of the primary power source. Example 18 includes the method of example 17, wherein determining if a condition of the primary power source crosses a first threshold comprises determining when a voltage of the primary power source drops below a low voltage threshold. Example 19 includes the method of example 18, wherein determining if a condition of the primary power source crosses a second threshold comprises determining when a voltage of the primary power source rises above a high voltage threshold that is higher than the low voltage threshold. Example 20 includes the method of any of examples 16-19, wherein turning on the first power field effect transistor comprises turning on the first power field effect transistor with an opto-isolator. Example 21 includes the method of any of examples 16-20, and further comprising determining if the back-up power source is providing power to another load prior to turning on the first power field effect transistor. Example 22 includes a system for providing sharing a common back-up power source for N loads. The system includes a back-up power port configured to be coupled to the common back-up power source, a plurality of primary power ports configured to be coupled to N primary power sources, a plurality of power selection circuits, each coupled to the common back-up power source and at least one of the plurality of primary power ports, a plurality of load ports, each coupled to one of the plurality of power selection circuits and configured to be coupled to provide power to one of the N loads, a control line, coupled to each of the plurality of power selection circuits, to communicate when one of the N power selection circuits is coupling the back-up power source to its load. Each of the power selections circuits includes a first port configured to be coupled to one of the N primary power sources, a second port configured to be coupled to the common back-up power source, a third port configured to be coupled to provide power to one of the N loads, first and second power field effect transistors (FET) coupled between the second port and the third port, a third power FET coupled between the first port and the third port, a dual ideal diode-OR controller coupled between the second and third power FETs to selectively turn on and off the second and third power FETs, an opto-isolator coupled to a control input of the first power FET, and a controller, coupled to the opto-isolator, that selectively turns on and off the opto-isolator. The controller monitors the power received at the first port and, when the power at the first port crosses a first threshold level, turns on the opto-isolator so that power is transmitted by the first and second power transistors between the second port and the third port and when the power at the first port crosses a second threshold level, turns off the opto-isolator so that power is transmitted by the third power transistor between the first port and the third port. A number of embodiments of the invention defined by the following claims have been described. Nevertheless, it will be understood that various modifications to the described embodiments may be made without departing from the spirit and scope of the claimed invention. Accordingly, other embodiments are within the scope of the following claims. | 33,575 |
11863014 | DETAILED DESCRIPTION FIG.1shows a power supply assembly101comprising a source connection system4, a load connection71, a DC link2, a direct-current converter81, a load supply converter82, a trickle charger converter84, a supply switch5, a control system909and a rechargeable direct-current supply461. The source connection system4comprises a primary source connection41adapted to be connected electrically to a primary alternating current supply301, and a secondary source connection42adapted to be connected electrically to a secondary current supply. The secondary source connection42is a direct current connection. The load connection71is adapted to be connected electrically to an alternating current load707. The direct-current converter81is connected electrically between the secondary source connection42and the DC link2. The direct-current converter81is adapted to supply power from the secondary source connection42to the DC link2. The DC link2comprises DC link capacitance. The load supply converter82is connected electrically between the DC link2and the load connection71. The load supply converter82is adapted to supply power from the DC link2to the load connection71. There is a supply converter filter829connected electrically between the load supply converter82and the load connection71. The supply converter filter829comprises filter capacitance. Due to its relatively high capacitance, the supply converter filter829causes significant reactive power in the power supply assembly. The trickle charger converter84is connected electrically between the load connection71and the secondary source connection42. There is a trickle charger capacitor24connected electrically between the secondary source connection42and the trickle charger converter84. The trickle charger converter84is adapted to supply power from the load connection71to the secondary source connection42. A nominal power of the trickle charger converter84is less than nominal powers of the direct-current converter81and the load supply converter82. A nominal power of the direct-current converter81is equal to a nominal power of the load supply converter82. A nominal power of the trickle charger converter84is 5% of the nominal power of the direct-current converter81. In an alternative embodiment, a nominal power of the trickle charger converter is less than or equal to 15% of the nominal power of the direct-current converter. In further alternative embodiments, the nominal power of the trickle charger converter is in a range of 1-10% of the nominal power of the direct-current converter. In yet further alternative embodiments, the nominal power of the trickle charger converter is in a range of 1-10% of the nominal power of the load supply converter. There is an internal galvanic isolation between an alternating current side and a direct current side of the trickle charger converter. In an embodiment, the galvanic isolation is adapted to operate at the converter pulse width modulation frequency. The trickle charger converter84has a different topology than the load supply converter82, and it utilizes different type of semiconductor switches. The trickle charger converter84is based on a very low loss topology such as resonant topology. The trickle charger converter84is based on a soft switching topology. The trickle charger converter84utilizes large band gap semiconductors such as silicon carbide (SiC) or gallium nitride (GaN) semiconductors. The trickle charger converter84is designed for an optimal point of operation consistently maintained. In an alternative embodiment, the trickle charger converter has an identical topology with the load supply converter, and they both utilize same type of semiconductor switches. It is even possible that the trickle charger converter and the load supply converter are, except for their nominal powers, identical with each other. In alternative embodiments, the trickle charger converter is connected electrically between at least one alternating current connection and the secondary source connection, the trickle charger converter being adapted to supply power from the at least one alternating current connection to the at least one secondary source connection. Said at least one alternating current connection comprises at least one of the load connection and the primary source connection. In an embodiment, the trickle charger converter, the direct-current converter, and the load supply converter are located inside a common housing. In an alternative embodiment, the trickle charger converter is located inside a different housing than the direct-current converter and the load supply converter. In an alternative embodiment, the power supply assembly comprises a plurality of secondary source connections each adapted to be connected electrically to a different secondary current supply. The different secondary current supplies comprise direct current supplies of different types, such as a battery and a capacitor. The primary source connection41is electrically conductively connected to the load connection71by means of alternating current supply route457for supplying power from the primary source connection41to the load connection71. The supply switch5is adapted to disconnect the alternating current supply route457thereby disconnecting the primary source connection41from the load connection71. The control system909is adapted to control the direct-current converter81, the load supply converter82, the trickle charger converter84and the supply switch5. The control system909is adapted to provide an energy saver mode, a direct-current supply mode, a charging mode, a trickle charging mode, and a reactive power compensation mode for the power supply assembly. In the energy saver mode, the supply switch5is in a conducting state for supplying power from the primary source connection41to the load connection71. In an embodiment, the direct-current converter and the load supply converter are in stand by states during the energy saver mode. In an alternative embodiment, the direct-current converter and the load supply converter are in off state during the energy saver mode. Herein, a stand by state is a state in which semiconductor switches of a converter are currentless, and only control circuits of the converter consume little power. In the direct-current supply mode, the supply switch5is in a non-conducting state, and power is supplied to the load connection71from the secondary source connection42through the direct-current converter81and the load supply converter82. In an embodiment, also the trickle charger converter takes part in supplying power to the load connection during the direct-current supply mode. The participation of the trickle charger converter in supplying power to the load connection during the direct-current supply mode increases a total power that can be supplied to the load connection during the direct-current supply mode. In the charging mode power is supplied to the secondary source connection42from the DC link2through the direct-current converter81. In an embodiment, also the trickle charger converter takes part in supplying power to the secondary source connection during the charging mode. In the trickle charging mode, power is supplied from the load connection71to the secondary source connection42exclusively through the trickle charger converter84. No power is supplied to the secondary source connection42through the direct-current converter81. A power of the charging mode is higher than the nominal power of the trickle charger converter. The charging mode is adapted to replenish the rechargeable direct-current supply461fast in a situation where there is no time to slowly recharge the rechargeable direct-current supply461by the trickle charger converter84. In an embodiment, the direct-current converter is in an off state during the trickle charging mode. In an alternative embodiment, the direct-current converter is in a stand by state during the trickle charging mode. In the reactive power compensation mode, reactive power is supplied from the trickle charger converter84to the load connection71. In an embodiment, reactive power is supplied exclusively from the trickle charger converter to the load connection. In said embodiment, the trickle charger converter is capable of compensating at least portion of reactive power caused by the supply converter filter. In an alternative embodiment, reactive power is supplied from both the trickle charger converter and the load supply converter to the load connection. In the embodiment ofFIG.1, each of the direct-current converter81, the load supply converter82and the trickle charger converter84are bidirectional converters. In an embodiment, in which the trickle charger converter does not take part in supplying power from the secondary source connection to the load connection, the trickle charger converter is a unidirectional converter. In another embodiment, in which no power is supplied from the load connection to the secondary source connection through the load supply converter and direct-current converter, the load supply converter and direct-current converter are unidirectional converters. In the power supply assembly shown inFIG.1, the trickle charger converter84consists of single unit. In an alternative embodiment, the trickle charger converter comprises a plurality of units connected in parallel. In a further alternative embodiment, the load supply converter comprises a plurality of units connected in parallel, and the direct-current converter comprises a plurality of units connected in parallel. It will be obvious to a person skilled in the art that the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims. | 9,865 |
11863015 | DETAILED DESCRIPTION Communication networks are built upon a conceptual model known as the Open Systems Interconnection (OSI) model100as shown in rough layer form inFIG.1. The OSI model100describes the functions of a communication system without knowledge of its intended use or purpose. The OSI model100is broken up into seven layers102,104,106,108,110,112, and114as is known in the art. Each of the seven layers of the OSI model serve a purpose, as is known in the art. As Ethernet communications are concerned, the Physical Layer, Layer1, is responsible for the physical connection (i.e. cabling) along with the negotiated parameters (i.e. speed) used in communicating between devices. The remaining layers are responsible for managing the flow of data being transmitted on top of the Physical Layer. All electronic devices require power in some form to operate. In the case of a Power over Ethernet (PoE) Lighting System, power to a powered device (PD) is supplied from a Power Sourcing Equipment (PSE) via a Category (Ethernet) cable to the PD. The PSE is responsible for providing power and data to its connected devices. A PSE can be one or more pieces of equipment. A PoE Network Switch is typically a single piece of hardware with the components needed to supply power and data. In contrast, a PSE can also be two pieces of hardware; a Network Switch and a Midspan. In this case, the Network Switch is responsible for the handling of data and the Midspan is responsible for injecting power on top of the data. In both cases, the power and data are transmitted together along the same Ethernet cable to the PD. Most PSEs obtain their power from a typical electrical system, i.e. high-voltage AC power from the building. This is considered a primary power source. Some PSEs support the connection of a secondary power source, i.e. a battery pack. These secondary sources provide power in the event the primary power source is unavailable. These methods ensure the PDs continue to operate in some fashion. A physical negotiated link is a link between a driver and a network switch, established by communication between the components. The physical negotiated link is a communication link with determined communication protocols for speed of communication and uni- or bi-directional communication capabilities between the two physical devices of the link. In one embodiment of the disclosure, the devices are a network switch and the driver. The negotiation can be an autonegotiation, or a directed negotiation with specific protocols. If at any time the data portion of the network switch is interrupted, and as long as the switch is still providing raw power, the node (the intelligent driver) sees that and defaults to emergency conditions, in this case turning emergency lighting on, overriding the normal operation of the lighting. PoE lighting requires both power and data for normal operation. Power is required to drive the control circuitry and ultimately the Light Emitting Diodes (LEDs). Data is required for control. Using data packets, the lighting system can instruct the networked lighting driver to turn on, off, dim and even adjust the color of the luminaire. Many advanced functions are also possible with the integration of connected sensors including, but not limited to daylight harvesting, occupancy and vacancy detection, temperature reporting and circadian rhythm functions. Building and occupancy codes require lighting systems to provide illumination in a power outage event and in some cases, emergencies. In the case of UL924, luminaires responsible for emergency lighting are required to provide illumination for a minimum of ninety minutes in the event of an electrical failure. With legacy lighting systems, most are based on a circuit methodology such as that shown in block diagram form inFIG.2A. In this case, a switch202is turned on allowing the flow of power from power source201to the connected luminaire203. While power is flowing, the luminaire203illuminates. FIG.2Bshows another legacy lighting system utilizing battery backup devices206between the power204and the luminaire207. In this system, a switch205is coupled between the battery backup device206and power204so that when power is available at the power source204, power is supplied therethrough. The backup unit206senses a loss of building power204by monitoring a power connection. If the primary power source204fails, the battery unit206begins sending stored power to the luminaire207until the primary power source204is once again available. While smaller buildings use backup units near the luminaire, larger buildings utilize centralized emergency power systems. While effective, these too are based on a circuit methodology. In both cases, these legacy lighting systems lack the functionality a PoE Lighting System can provide. Unlike circuit based, legacy lighting systems, PoE Lighting Systems always have power flowing to a networked driver responsible for controlling a luminaire. Therefore, the mere presence of power to the networked driver will not allow triggering emergency illumination on a switch to auxiliary or backup power, as power is already flowing to the networked driver. As such, the need for data communication across the network is required to trigger the networked driver. In the event of a power outage or emergency, this is not always possible as the network may not be viable. Some smaller PoE lighting deployments are utilizing battery backup devices at the luminaire. While functional, they are not appropriate for larger buildings as their deployment and management is complicated and costly. Some networked lighting deployments have utilized a timeout method in which if the networked driver loses bi-directional communication with a central controller for a defined period, the networked driver will then engage the power output to the luminaire. While this eventually results in supply of emergency lighting, this not ideal as it is not immediate as it relies on a timeout period elapsing. Furthermore, false power outage positives can be realized by the networked driver if maintenance on the central controller is performed, resulting in unintended illumination. Embodiments of the present disclosure provide a methodology and structure in which a PoE Lighting System, through the monitoring of a physical negotiated link, immediately illuminates a luminaire in the event of a primary power outage or other emergency condition. Furthermore, the same methodology can be deemed useful in the event of a network communication failure. As mentioned herein, the Ethernet Physical Layer (layer102of the OSI100) is responsible for providing the physical negotiated link (e.g., the connection) between the PSE and the PD. This physical connection is responsible for the delivery of power and negotiating a physical link wherein the PSE and PD have established connection parameters relating to speed and unidirectional or bidirectional communication capabilities of both devices. In one embodiment, through the monitoring of the physical negotiated link, the networked driver is designed such that in the event the physical negotiated link is lost, the networked driver immediately initiates power delivery to the luminaire in an emergency lighting mode, resulting in illumination of the space. FIG.3shows a PoE lighting system deployment300according to one embodiment. In this scenario, power is provided by a midspan305to a networked driver306. Power to the midspan is provided either by building power301or battery backup309. In the event the building power301is lost, both the network switch304and the midspan305lose their primary power source. In this case, the midspan305has a battery backup309as a secondary power source. Normally, the networked driver306will not notice any change as the midspan305immediately supplies stored power to the networked driver306. In this embodiment, the power is being supplied by the midspan305, but the physical negotiated link between the network switch304and the driver306is being provided by the network switch304. With the network switch304losing power, the networked driver306detects the loss of the physical negotiated link and initiates flow of power for emergency lighting to the luminaire307immediately. PSE311components in various embodiments may be programmed or otherwise controlled by using a computer310or other control device308. Upon the return of the building power, the networked switch304reboots, and upon a restoration of the physical negotiated link with the networked driver306, the system returns to normal operation. A state diagram for operation of this embodiment is shown inFIG.4. Provided the driver has power as shown in block402, and a physical negotiated link is present between the driver and the network switch as determined in block406, operation is normal as shown in block408. If the physical negotiated link is detected by the driver as lost as shown in block406, the driver switches the luminaire on a shown in block404. Loss of the physical negotiated link results in emergency operation that overrides normal operation, and it occurs immediately since the system still has power, whether that power is building power or backup power, or power supplied by a midspan or directly. FIG.5shows a different lighting system embodiment500. In this embodiment, power and data is provided by a PSE/PoE switch503. As in many cases, larger PoE switches are used in networked lighting deployments and have multiple power supplies for flexibility and redundancy. Through proper assembly, the building power501may be connected to one power supply of PSE/PoE switch503, and may be switched manually or automatically at switch502. The emergency power source508may be connected to a second power supply of PSE/PoE switch503, and may be switched manually or automatically to emergency power at switch509. In this embodiment, when the building power501is lost, the PSE/PoE switch503sources its power from the emergency power source508. The PSE/PoE switch503is configured in another embodiment to sever or momentarily drop its physical negotiated link with the networked driver505in this scenario, resulting in the networked driver505sending power to the luminaire507under emergency lighting conditions. PSE/PoE switch503in various embodiments may be programmed or otherwise controlled by using a computer504or other control device506. FIG.6expands on the methodology shown prior. In this process, the time at which the physical negotiated link is lost will be recorded by the networked driver. Upon the return of the physical negotiated link, the time will be recorded again along with the amount of power supplied to the luminaire during the outage by the networked driver. This data can then be sent to a central system for verification, validation and logging. A state diagram450for operation of the embodiment500is shown inFIG.6. As with the state diagram ofFIG.4, provided the driver has power as shown in block402, and a physical negotiated link is present between the driver and the network switch as determined in block406, operation is normal as shown in block408. If the physical negotiated link is detected by the driver as lost as shown in block406, the driver switches the luminaire on a shown in block404. Additional processes occur in a system such as system500as shown in state diagram450, although it should be understood that the additional processes may also be used with other embodiments of the present disclosure without departing from the scope thereof. When a physical negotiated link is lost as indicated, the time that the signal is lost is recorded at452. When the physical negotiated link is restored as indicated in block406, a check is made at block454as to whether a loss time has been recorded. If no, normal operation continues at408. If a loss time has been recorded, a time of restoration of the negotiated physical link is recorded at456, an amount of power used during the low time from the time recorded at452to the time recorded at456is determined at block458, data corresponding to the loss time frame and the recorded power consumption is stored or sent for processing at460, and normal operation is initiated at408. All of the states and the process ofFIGS.4and6may be performed in one embodiment automatically according to programming of the operation of the various deployments such as but not limited to those shown inFIGS.3and5. In the embodiments of the present disclosure, a loss of the physical negotiated link results in emergency operation that overrides normal operation. This emergency operation is initiated immediately as long as the system still has power, whether that power is building power or backup power, or power supplied by a midspan or directly. It should be understood that determination of the loss of the physical negotiated link may be by any process, including use of a microprocessor, or through a series of logic gates without any microprocessor, as will be understood by those of ordinary skill in the art. As long as loss of the physical negotiated link is detected, then any process which initiates emergency operation of the lighting is well within the scope of one skilled in the art. | 13,280 |
11863016 | FIG.1shows a perspective view, partially in section, of an arrangement25comprising an electric motor1.FIG.2shows the electric motor1of the arrangement25according toFIG.1in a view along the rotation axis3.FIG.3shows the electric motor1according toFIG.2in a view along the rotation axis3with a course of the magnetic flux30.FIG.4shows a perspective view of the electric motor1according toFIGS.2and3.FIGS.1to4will be described together in the text which follows. The electric motor1comprises a rotor2with a rotation axis3and comprises an annular stator4which surrounds the rotor2and is arranged coaxially to the rotor2. The stator4extends along an axial direction5that is parallel to the rotation axis3and respectively has a first end side6and a second end side7that point in opposite axial directions5. The stator4has precisely two stator teeth8,9which, starting from an annular circumferential surface10of the stator4, which circumferential surface extends between the end sides5,6, extend along a radial direction11inward toward the rotor2and are arranged opposite one another with respect to the rotation axis3(that is to say offset in relation to one another through 180 angular degrees in a circumferential direction27). A first stator slot12and a second stator slot13, which is arranged opposite with respect to the rotation axis3, extend along the circumferential surface10between the first stator tooth8and the second stator tooth9. A plurality of first windings14are arranged in the first stator slot12and a plurality of second windings15are arranged in the second stator slot13, wherein each winding14extends over the end sides6,7and on the outside and on the inside in the radial direction11around the circumferential surface10. InFIGS.1to3, the parts of each of the windings14,15that extend along the end sides6,7along the radial direction11are cut away and therefore not illustrated. The complete windings14,15are illustrated only inFIG.4. The windings14,15do not extend around the stator teeth8,9, but rather only around the annular circumferential surface10. Individual windings14,15are arranged adjacent to one another along the circumferential direction27. The first winding14and the second windings14,15are arranged in relation to one another and electrically connected to one another such that a magnetic flux30, which can be generated by the respective winding14,15during operation of the electric motor1, is directed through the circumferential surface10(the main body of the stator4) along opposite circumferential directions27in the region of the stator slots12,13and is added up in the region of the stator teeth8,9and can be conducted across the stator teeth8,9and the rotor2along the radial direction11(seeFIGS.1,3and4). Here, the first windings14and the second windings15are connected to one another in parallel. The first windings14and the second windings15are windings14,15that are independent of one another. A plurality of windings14,15are arranged in each stator slot12,13, wherein the windings14,15of one stator slot12,13(that is to say first windings14in the first stator slot12or second windings15in the second stator slot13) are connected to one another in series (see indication inFIG.1). Therefore, here, the first windings14are connected to one another in series. Furthermore, the second windings15are connected to one another in series. The first windings14and the second windings15are connected to one another in parallel. Here, an identical number of windings14,15are arranged in the two stator slots12,13. One winding14,15extends at least along the axial direction5along the circumferential surfaces10(that is to say on the outside and on the inside of the circumferential surface10) and along the radial direction11beyond the end sides6,7of the annular stator4and in so doing over the end sides6,7and in the radial direction11on the outside and on the inside around the circumferential surface10. The arrangement of the windings14,15through which an electric current16flows in opposite directions in stator slots12,13that are separated from one another by the two stator teeth8,9allows the magnetic field lines (or the magnetic flux30) to be conducted along the circumferential direction27through the main body of the stator4and through the winding14,15toward the stator tooth8,9. At the first stator tooth8, the magnetic field lines (the magnetic flux30) exit from the windings14,15of the opposite stator slots12,13and are guided along the radial direction11through the first stator tooth8toward the rotor2and across the rotor2toward the second stator tooth9. At this second stator tooth9, the magnetic field lines (the magnetic flux30) are guided toward the main body of the stator4and there passed on through the windings14,15and through the main body of the stator4in the circumferential direction27. The different polarized ends of each winding14,15or of the electrical conductor that forms the at least one winding14,15in the respective stator slot12,13are therefore at a maximum distance from one another, and therefore a stray field is as small as possible. One end of the electrical conductor of a stator slot is arranged, in particular, in the immediate vicinity of one stator tooth8,9and the other end is arranged in the immediate vicinity of the other stator tooth9,8(seeFIG.1). In this embodiment of an electric motor1, a stray field can be kept small, wherein an air gap or distance18between the stator tooth8,9and the rotor2can be designed to be particularly large. Therefore, the diameter of the rotor2can be designed to be small, and therefore the intermediate space24of the motor1can be realized with a large throughflow cross section. The stator teeth8,9, starting from an annular circumferential surface10of the stator4, which circumferential surface extends between the end sides6,7, extend along a radial direction11inward toward the rotor2as far as an inner circumferential surface20of the stator tooth8,9. Along this extent33, the stator tooth8,9has a tapered portion34with respect to the circumferential direction27, i.e. a width of the stator tooth8,9, which width extends in the circumferential direction27, is at minimum between the circumferential surface10of the stator4, which circumferential surface points inward in the radial direction11, and the inner circumferential surface20of the stator tooth8,9. The inner circumferential surface20of the stator teeth8,9is of wider design along the circumferential direction27than the region of the stator tooth8,9between the circumferential surface10of the stator4and the tapered portion34. The stator tooth8,9extends along the radial direction11and, starting from the circumferential surface10of the stator4, over a first section35toward the tapered portion34and, starting from the tapered portion34, over a second section36toward the inner circumferential surface20. The second section36extends in the circumferential direction27over a second angular range38of approximately 90 angular degrees which exceeds a greatest first angular range37of approximately 30 angular degrees of the first section35by approximately 200%. The angular range37,38is determined starting from a rotation axis3of the motor1. The first section35as far as the tapered portion34extends starting from the circumferential surface10of the stator4and along the radial direction11inward beyond the windings14,15. The first section35comprises approximately 75% of the extent33of the stator tooth8,9along the radial direction11. The two stator slots12,13each extend over a third angular range39of approximately 150 angular degrees along the circumferential direction27. The at least one winding14,15, which extends around the circumferential surface10of the stator4and is arranged only in one stator slot12,13, extends over a proportion of approximately 97% of this third angular range39. The rotor2has (next to one another along the circumferential direction27) two poles17of a permanent magnet, which two poles are respectively magnetized in the radial direction11(seeFIG.2). The poles17are arranged offset in relation to one another through 180 angular degrees along the circumferential direction27and point in opposite radial directions11. The poles17are separated from one another by a boundary which extends transversely to an extent33of the stator teeth8,9here (dashed line inFIG.2). A smallest distance18between an outer circumferential surface19of the rotor2and an inner circumferential surface20of the stator teeth8,9is at least 5 millimeters. FIGS.1and4show that the stator teeth8,9extend beyond the two end sides6,7along the axial direction5and in so doing form a projection40on each end side6,7. This projection40extends over the entire extent33of the respective stator tooth8,9along the radial direction11. Therefore, the inner circumferential surface20of the respective stator tooth8,9, which inner circumferential surface is situated opposite the rotor2, can be increased in size, so that, with a given electric current, a magnetic flux density in the region of the inner circumferential surface20of the stator teeth8,9can be reduced and a magnetic reluctance can be lowered. A bearing21of the rotor2is arranged outside the stator4along the axial direction5. The rotor2(but in particular not the poles17of the magnet) extends beyond the extent of the stator4, that is to say at least beyond an end side6,7, here the first end side6, along the axial direction5. The poles17may possibly also extend beyond the extent of the stator4, so that a possible torque can be increased. The rotor2has a structure22for conveying a fluid23along the axial direction5through an intermediate space24formed between the rotor2and the stator4. During operation of the motor1, the structure23displaces the fluid23in the axial direction5, so that a fluid flow through the intermediate space24can be generated. The arrangement25illustrated inFIG.1comprises the motor1and a voltage source26. The voltage source26is, in particular, a sinusoidal source (and not a DC source) or a switchable voltage source or power electronics system. The plurality of first windings14and the plurality of second windings15are arranged in relation to one another and connected such that an electric current16can flow through them in opposite directions, so that a magnetic flux30, starting from the poles17of the magnet, is conducted across the stator teeth8,9in the radial direction11into the circumferential surface10of the stator4and through the circumferential surface10of the stator4along the circumferential direction27. FIG.5shows a graph. A rotation speed29in revolutions per minute of the electric motor1is plotted on the horizontal axis. A torque28, which can be generated by the electric motor1, in Newton meters is plotted on the vertical axis. The first profile31shows the torque28of an electric motor1of different construction. The second profile32shows the achievable torque28of the electric motor1described here, which achievable torque is higher at almost all operating points. LIST OF REFERENCE SIGNS 1Motor2Rotor3Rotation axis4Stator5Axial direction6First end side7Second end side8First stator tooth9Second stator tooth10Circumferential surface11Radial direction12First stator slot13Second stator slot14First winding15Second winding16Current [amperes], that is to say [A]17Pole18Distance19Outer circumferential surface20Inner circumferential surface21Bearing22Structure23Fluid24Intermediate space25Arrangement26Voltage source27Circumferential direction28Torque [Newton meters], that is to say [Nm]29Rotation speed [revolutions per minute], that is to say [rpm]30Magnetic flux [Tesla square meters], that is to say [T*m2]31First profile32Second profile33Extent34Tapered portion35First section36Second section37First angular range38Second angular range39Third angular range40Projection | 11,886 |
11863017 | EMBODIMENTS FOR IMPLEMENTING THE INVENTION Hereinafter, a laminated core and an electric motor according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a motor, specifically an AC motor will be exemplified as the electric motor. The AC motor is more specifically a synchronous motor, and even more specifically, a permanent magnetic electric motor. This type of motor is suitably adopted for, for example, an electric vehicle. As shown inFIGS.1and2, an electric motor10includes a stator20, a rotor30, a case50, and a rotation shaft60. The stator20and the rotor30are accommodated in the case50. The stator20is fixed to the case50. In the present embodiment, as the electric motor10, an inner rotor type electric motor in which the rotor30is located inside the stator20is adopted. However, as the electric motor10, an outer rotor type electric motor in which the rotor30is located outside the stator20may be adopted. Further, in the present embodiment, the electric motor10is a 12-pole 18-slot three-phase AC motor. However, for example, the number of poles, the number of slots, the number of phases, and the like can be changed as appropriate. The stator20includes a stator core21and a winding (not shown). The stator core21includes an annular core back part22and a plurality of tooth parts23. In the following, an axial direction (a direction of a central axis O of the stator core21) of the stator core21(the core back part22) is referred to as an axial direction, a radial direction (a direction orthogonal to the central axis O of the stator core21) of the stator core21(the core back part22) is referred to as a radial direction, and a circumferential direction (a direction of rotation around the central axis O of the stator core21) of the stator core21(the core back part22) is referred to as a circumferential direction. The core back part22is formed in an annular shape in a plan view of the stator20when seen in the axial direction. The plurality of tooth parts23protrude from the core back part22inward in the radial direction (toward the central axis O of the core back part22in the radial direction). The plurality of tooth parts23are disposed at equal intervals in the circumferential direction. In the present embodiment, 18 tooth parts23are provided at an interval of 20 degrees of a central angle centered on the central axis O. The plurality of tooth parts23are formed to have the same shape and the same size as each other. The winding is wound around the tooth part23. The winding may be a concentrated winding or a distributed winding. The rotor30is disposed inside the stator20(the stator core21) in the radial direction. The rotor30includes a rotor core31and a plurality of permanent magnets32. The rotor core31is formed in an annular shape (an annular ring) disposed coaxially with the stator20. The rotation shaft60is disposed in the rotor core31. The rotation shaft60is fixed to the rotor core31. The plurality of permanent magnets32are fixed to the rotor core31. In the present embodiment, a set of two permanent magnets32forms one magnetic pole. The plurality of sets of permanent magnets32are disposed at equal intervals in the circumferential direction. In the present embodiment, 12 sets of (24 in total) permanent magnets32are provided at an interval of 30 degrees of the central angle centered on the central axis O. In the present embodiment, an interior permanent magnet motor is adopted as a permanent magnetic electric motor. A plurality of through-holes33which pass through the rotor core31in the axial direction are formed in the rotor core31. The plurality of through-holes33are provided corresponding to the plurality of permanent magnets32. Each of the permanent magnets32is fixed to the rotor core31in a state in which it is disposed in the corresponding through-hole33. Each of the permanent magnets32is fixed to the rotor core31, for example, by adhering an outer surface of the permanent magnet32and an inner surface of the through-hole33with an adhesive or the like. As the permanent magnetic electric motor, a surface permanent magnet motor may be adopted instead of an interior permanent magnet motor. Both the stator core21and the rotor core31are laminated cores. The laminated core is formed by stacking a plurality of electrical steel sheets40. A stacking thickness of each of the stator core21and the rotor core31is, for example, 50.0 mm. An outer diameter of the stator core21is, for example, 250.0 mm. An inner diameter of the stator core21is, for example, 165.0 mm. An outer diameter of the rotor core31is, for example, 163.0 mm. An inner diameter of the rotor core31is, for example, 30.0 mm. However, these values are examples, and the stacking thickness, the outer diameter and the inner diameter of the stator core21, and the stacking thickness, the outer diameter and the inner diameter of the rotor core31are not limited to these values. Here, the inner diameter of the stator core21is based on a tip end portion of the tooth part23of the stator core21. The inner diameter of the stator core21is a diameter of a virtual circle inscribed in the tip end portions of all the tooth parts23. Each of the electrical steel sheets40forming the stator core21and the rotor core31is formed, for example, by punching an electrical steel sheet as a base material. As the electrical steel sheet40, a known electrical steel sheet can be used. A chemical composition of the electrical steel sheet40is not particularly limited. In the present embodiment, a non-grain-oriented electrical steel sheet is adopted as the electrical steel sheet40. As the non-grain-oriented electrical steel sheet, for example, a non-grain-oriented electrical steel strip of JIS C 2552:2014 can be adopted. However, as the electrical steel sheet40, it is also possible to adopt a grain-oriented electrical steel sheet instead of the non-grain-oriented electrical steel sheet. As the grain-oriented electrical steel sheet, for example, a grain-oriented electrical steel strip of JIS C 2553:2012 can be adopted. Insulation coatings are provided on both surfaces of the electrical steel sheet40in order to improve workability of the electrical steel sheet and iron loss of the laminated core. For example, (1) an inorganic compound, (2) an organic resin, (3) a mixture of an inorganic compound and an organic resin, and the like can be applied as a substance constituting the insulation coating. Examples of the inorganic compound include (1) a complex of dichromate and boric acid, (2) a complex of phosphate and silica, and the like. Examples of the organic resin include an epoxy-based resin, an acrylic-based resin, an acrylic-styrene-based resin, a polyester-based resin, a silicone-based resin, a fluorine-based resin, and the like. In order to ensure insulating performance between the electrical steel sheets40stacked with each other, a thickness of the insulation coating (a thickness per one surface of the electrical steel sheet40) is preferably 0.1 μm or more. On the other hand, an insulating effect saturates as the insulation coating becomes thicker. Further, as the insulation coating becomes thicker, a space factor decreases, and the performance as a laminated core deteriorates. Therefore, the insulation coating should be as thin as possible within a range in which the insulating performance is ensured. The thickness of the insulation coating (the thickness per one surface of the electrical steel sheet40) is preferably 0.1 μm or more and 5 μm or less. The thickness of the insulation coating is more preferably 0.1 μm or more and 2 μm or less. As the electrical steel sheet40becomes thinner, an effect of improving the iron loss gradually saturates. Further, as the electrical steel sheet40becomes thinner, manufacturing cost of the electrical steel sheet40increases. Therefore, the thickness of the electrical steel sheet40is preferably 0.10 mm or more in consideration of the effect of improving the iron loss and the manufacturing cost. On the other hand, when the electrical steel sheet40is too thick, a press punching operation of the electrical steel sheet40becomes difficult. Therefore, when considering the press punching operation of the electrical steel sheet40, the thickness of the electrical steel sheet40is preferably 0.65 mm or less. Further, as the electrical steel sheet40becomes thicker, the iron loss increases. Therefore, when considering iron loss characteristics of the electrical steel sheet40, the thickness of the electrical steel sheet40is preferably 0.35 mm or less. The thickness of the electrical steel sheet40is more preferably 0.20 mm or 0.25 mm. In consideration of the above points, the thickness of each of the electrical steel sheets40is, for example, 0.10 mm or more and 0.65 mm or less. The thickness of each of the electrical steel sheets40is preferably 0.10 mm or more and 0.35 mm or less, and more preferably 0.20 mm or 0.25 mm. The thickness of the electrical steel sheet40includes the thickness of the insulation coating. As shown inFIG.3, the plurality of electrical steel sheets40forming the stator core21are stacked in a thickness direction. The thickness direction is a thickness direction of the electrical steel sheet40. The thickness direction corresponds to the stacking direction of the electrical steel sheets40. InFIG.3, for convenience, the tooth part23is not shown. The plurality of electrical steel sheets40are disposed coaxially with respect to the central axis O. The electrical steel sheet40includes a core back part22and a plurality of tooth parts23. In the stator core21, as shown inFIGS.4and5, an adhesion part41for adhering the electrical steel sheets40is disposed between the electrical steel sheets40adjacent to each other in the stacking direction. The adhesion part41partially adheres the electrical steel sheets40adjacent to each other in the stacking direction. The adhesion parts41adjacent to each other in the stacking direction have different arrangement regions in a plan view seen in the stacking direction. A range in which the adhesion parts41adjacent to each other in the stacking direction are disposed so that arrangement regions thereof are different from each other in a plan view seen in the stacking direction (hereinafter, referred to as an arrangement range in which the arrangement regions are different from each other) may be the entire stator core21and may be a part of the stator core21. Specifically, the arrangement range in which the arrangement regions are different from each other may be in one of the plurality of tooth parts23arranged in the circumferential direction. The arrangement range in which the arrangement regions are different from each other may be in one of layers formed by the plurality of adhesion parts41, which will be described later, arranged in the stacking direction. Here, the arrangement region is a region on a surface (a first surface)40aof the electrical steel sheet40on which the adhesion part41is disposed. That is, the arrangement region is an adhesion region on the surface40aof the electrical steel sheet40on which the adhesion part41is provided. The adhesion region in which the adhesion part41is provided and a non-adhesion region in which the adhesion part41is not provided are formed on the surface40aof the electrical steel sheet40. The adhesion region of the electrical steel sheet40in which the adhesion part41is provided means a region of the first surface40aof the electrical steel sheet40in which the adhesive cured without being divided is provided. Further, the non-adhesion region of the electrical steel sheet40in which the adhesion part41is not provided means a region on the first surface40aof the electrical steel sheet40in which the adhesive cured without being divided is not provided. Here, an adhesive which is cured without being divided between the electrical steel sheets40adjacent to each other in the stacking direction is referred to as one adhesion part41. Here, as shown inFIGS.2,4and5, a stacking surface of the core back part22is referred to as a surface22a. A stacking surface of the tooth part23is referred to as a surface23a. At this time, the adhesion part41is preferably provided on at least one of the surface22aof the core back part22and the surface23aof the tooth part23in the electrical steel sheet40. That is, the adhesion part41may be provided only on the surface22aof the core back part22in the electrical steel sheet40. The adhesion part41may be provided only on the surface23aof the tooth part23in the electrical steel sheet40. The adhesion part41may be provided on both the surface22aof the core back part22and the surface23aof the tooth part23in the electrical steel sheet40. In the present embodiment, one or a plurality of adhesion parts41may form a layer (hereinafter, also referred to as a layer formed by the adhesion parts41) between the two electrical steel sheets40. In other words, the layer formed by the adhesion part41includes one or the plurality of adhesion parts41. A plurality of layers formed by the adhesion part41are provided in the stacking direction. Preferably, the adhesion part41is provided so that the arrangement regions overlap at an N-layer interval (N is a natural number) in a plan view seen in the stacking direction. The N-layer interval means an N-layer interval in the layers by the adhesion part41. In other words, preferably, each of the adhesion parts41is disposed at the same position in the electrical steel sheet40at the N-layer interval (N is a natural number) in the layers formed by the adhesion part41. In a plan view seen in the stacking direction, preferably, the arrangement regions of the adhesion part41overlap at the N-layer interval over the entire length of the stator core21in the stacking direction. The fact that the arrangement regions of the adhesion part41overlap at the N-layer interval in the plan view seen in the stacking direction means that the arrangement regions of the adhesion part41overlap at the N-layer interval in the plan view seen in the stacking direction at least some of the layers formed by the plurality of adhesion parts41arranged in the stacking direction in one of the plurality of tooth parts23arranged in the circumferential direction. Further, N is preferably 1 or a prime number. In the present embodiment, N=1. In the present embodiment, a case in which the adhesion part41is provided only on the surface23aof the tooth part23is shown. Hereinafter, the plurality of tooth parts23included in each of the electrical steel sheets40are also referred to as tooth parts23A to23R in the clockwise order as shown inFIGS.4and5. The plurality of electrical steel sheets40included in the stator core21are also referred to as electrical steel sheets400,40A,40B, . . . in the order from the first side in the stacking direction to the second side opposite to the first side in the stacking direction (refer toFIG.8). The adhesion parts41are disposed at positions adjacent to the first side in the stacking direction with respect to the electrical steel sheets40A,40B, . . . . The adhesion part41is not disposed at a position adjacent to the first side in the stacking direction with respect to the electrical steel sheet400. The adhesion part41is disposed at a position adjacent to the second side in the stacking direction with respect to the electrical steel sheet400. In the following, the adhesion part41disposed (provided) on the electrical steel sheet40means the adhesion part41disposed at a position adjacent to the first side in the stacking direction with respect to the electrical steel sheet40. The tooth parts23A of the electrical steel sheets40overlap each other in a plan view seen in the stacking direction. The same applies to the tooth parts23B to23R of each of the electrical steel sheets40. When N=1, as shown inFIG.4, in the electrical steel sheet40A, the adhesion part41is provided on the surface23aof each of the tooth parts23A,23C,23E,23G,23I,23K,23M,23O, and23Q. Further, as shown inFIG.5, in the electrical steel sheet40B adjacent to the electrical steel sheet40A in the stacking direction, the adhesion part41is provided on the surface23aof each of the tooth parts23B,23D,23F,23H,23J,23L,23N,23P, and23R. Each of the adhesion parts41is formed in a strip shape in a plan view and is disposed along an exterior of the tooth part23. An arrangement pattern of another adhesion part41in the stator core21is exemplified. As shown inFIGS.6and7, in this example, 18 tooth parts23(23A to23R) are provided at an interval of 20 degrees of a central angle centered on the central axis O. In the electrical steel sheet40A, each of the adhesion parts41extends from the surface23aof each of the tooth parts23A,23C,23E,23G,23I,23K,23M,23O, and23Q to an outer peripheral edge of the core back part22in the radial direction along the tooth parts23. In the electrical steel sheet40B, each of the adhesion parts41extends from the surface23aof each of the tooth parts23B,23D,23F,23H,23J,23L,23N,23P, and23R to an outer peripheral edge of the core back part22in the radial direction along the tooth parts23. Further, as shown inFIG.8, in the stator core21of this example, 11 electrical steel sheets40(400to40J) are stacked. In the following, for ease of explanation, the stator core21including 11 electrical steel sheets40will be described as an example. However, the stator core21may include 12 or more electrical steel sheets40. The case of the stator core21in which N=1 is shown inFIGS.6and7and Table 1. In this case, the adhesion parts41are provided so that the arrangement regions overlap at a one-layer interval in the plan view seen in the stacking direction. In Table 1, a portion marked with ∘ (a column in which ∘ is described) indicates an outer portion (hereinafter, referred to as a core back outer part of the tooth part23) of the tooth part23in the radial direction in (1) the tooth part23on which the adhesion part41is disposed and (2) the core back part22on which the adhesion part41is disposed. In the following, the tooth part23and the core back outer part of the tooth part23will also be referred to as the tooth part23and the like. Corresponding to the column in which ∘ is described, the adhesion part41may be disposed only on one of the tooth part23and the core back outer part of the tooth part23. The stator core21of this example includes the electrical steel sheet400. However, as will be described later, since the adhesion part41is not disposed on the electrical steel sheet400, the electrical steel sheet400is not shown in Table 1. Also in Tables 2 to 5 which will be described later, the electrical steel sheet400is not shown in each of the tables. For example, in Table 1, ∘ is shown in the column of the tooth part23A of the electrical steel sheet40A. This description means that the adhesion part41is disposed at a position adjacent to the first side in the stacking direction with respect to the tooth part23A of the electrical steel sheet40A. This description further means that the adhesion part41is disposed at a position adjacent to the first side in the stacking direction with respect to the core back outer part of the tooth part23A of the electrical steel sheet40A. Hereinafter, the layer formed by the adhesion part41disposed on the first side in the stacking direction with respect to the electrical steel sheet40A is referred to as a layer formed by the adhesion part41corresponding to the electrical steel sheet40A. The same is applied to the electrical steel sheets40B to40J. On the other hand, ∘ is not described in the column of the tooth part23A of the electrical steel sheet40B. This description means that the adhesion part41is not disposed at a position adjacent to the first side in the stacking direction with respect to the tooth part23A of the electrical steel sheet40B. This description further means that the adhesion part41is not disposed at a position adjacent to the first side in the stacking direction with respect to the core back outer part of the tooth part23A of the electrical steel sheet40B. In the case of the stator core21in which N=1, as shown inFIG.6and Table 1, in the electrical steel sheets40A,40C,40E,40G, and40I, the adhesion part41is provided on the surface23aof each of the tooth parts23of a first group which will be described later and the surface22aof a radial outer portion of each of the tooth parts23of the first group in the core back part22. The tooth parts23of the first group referred to here mean the tooth parts23A,23C,23E,23G,23I,23K,23M,23O, and23Q. Further, as shown inFIG.7and Table 1, in the electrical steel sheets40B,40D,40F,40H, and40J, the adhesion part41is provided on the surface23aof each of the tooth parts23of a second group which will be described later and the surface22aof a radial outer portion of each of the tooth parts23of the second group in the core back part22. The tooth parts23of the second group referred to here mean the tooth parts23B,23D,23F,23H,23J,23L,23N,23P, and23R. In this example, two types of layers formed by adhesion parts41having different shapes in a plan view are provided in the stator core21. The layers formed by two types of adhesion parts41correspond to the tooth parts23of the first group and the tooth parts23of the second group. Here, among the layers formed by the two types of adhesion parts41, the layers formed by the adhesion parts41having different shapes in the plan view are referred to as a layer formed by a first type of adhesion part41and a layer formed by a second type of adhesion part41. In all the layers formed by the two types of adhesion parts41, the adhesion parts41are disposed on the tooth parts23and the like at an interval of one tooth part23in the circumferential direction. However, for example, when the adhesion part41is disposed on the tooth part23A and the like in the layer formed by the first type of adhesion part41, the adhesion part41is not disposed on the tooth part23A and the like in the layer formed by the second type of adhesion part41. On the other hand, when the adhesion part41is not disposed on the tooth part23A and the like in the layer formed by the first type of adhesion part41, the adhesion part41is disposed on the tooth part23A and the like of the layer formed by the second type of adhesion part41. The same is applied to the tooth parts23B to23R. Then, the layers formed by the two types of adhesion parts41are alternately disposed in the stacking direction. In other words, shapes of the layers formed by the adhesion part41in the plan view are the same at a one-layer interval. When 12 or more electrical steel sheets40are stacked (provided) in the stator core21, the stator core21is configured as follows. That is, another electrical steel sheet40A is stacked next to the electrical steel sheet40J (at a position adjacent to the second side in the stacking direction with respect to the electrical steel sheet40J). Hereinafter, the other electrical steel sheets40B to40J are stacked in this order at positions adjacent to the second side in the stacking direction with respect to the other electrical steel sheet40A. TABLE 123A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘∘∘∘∘∘∘40B∘∘∘∘∘∘∘∘∘40C∘∘∘∘∘∘∘∘∘40D∘∘∘∘∘∘∘∘∘40E∘∘∘∘∘∘∘∘∘40F∘∘∘∘∘∘∘∘∘40G∘∘∘∘∘∘∘∘∘40H∘∘∘∘∘∘∘∘∘40I∘∘∘∘∘∘∘∘∘40J∘∘∘∘∘∘∘∘∘ A case of the stator core21in which N=2 (a prime number) is shown inFIGS.9to11and Table 2. In this case, the adhesion part41is provided so that the arrangement regions overlap at a two-layer interval in a plan view seen in the stacking direction. In Table 2, a portion marked with ∘ indicates the tooth part23on which the adhesion part41is disposed and the outer portion of the tooth part23in the radial direction in the core back part22(the tooth part23and the like). In the case of the stator core21in which N=2 (a prime number), as shown inFIG.9and Table 2, in the electrical steel sheets40A,40D,40G and40J, the adhesion part41is provided on the surface23aof each of the tooth parts23of a sixth group which will be described later, and the surface22aof the radial outer portion of each of the tooth part23of the sixth group in the core back part22. The tooth parts23of the sixth group referred to here mean the tooth parts23A,23D,23G,23J,23M, and23P. Further, as shown inFIG.10and Table 2, in the electrical steel sheets40B,40E, and40H, the adhesion part41is provided on the surface23aof each of the tooth parts23of a seventh group which will be described later, and the surface22aof the radial outer portion of each of the tooth part23of the seventh group in the core back part22. The tooth parts23of the seventh group referred to here mean the tooth parts23B,23E,23H,23K,23N, and23Q. Further, as shown inFIG.11and Table 2, in the electrical steel sheets40C,40F, and40I, the adhesion part41is provided on the surface23aof each of the tooth parts23of an eighth group which will be described later, and the surface22aof the radial outer portion of each of the tooth part23of the eighth group in the core back part22. The tooth parts23of the eighth group referred to here mean the tooth parts23C,23F,23I,23L,23O, and23R. In this example, three types of layers formed by adhesion parts41having different shapes in a plan view are provided in the stator core21. The layers formed by three types of adhesion parts41corresponds to the tooth parts23of the sixth group, the tooth parts23of the seventh group, and the tooth parts23of the eighth group. In all the layers formed by the three types of adhesion parts41, the adhesion parts41are disposed on the tooth parts23and the like at an interval of two tooth parts23in the circumferential direction. Here, among the layers formed by the three types of adhesion parts41, the layers formed by the adhesion parts41having different shapes in the plan view are referred to as a layer formed by a first type of adhesion part41, a layer formed by a second type adhesion part41, and a layer formed by a second type of adhesion part41. The tooth part23and the like on which the adhesion part41is disposed in the layer formed by the second type of adhesion part41are shifted to the first side by one tooth part23and the like in the circumferential direction with respect to the tooth part23and the like on which the adhesion part41is disposed in the layer formed by the first type of adhesion part41. The tooth part23and the like on which the adhesion part41is disposed in the layer formed by the third type of adhesion part41are shifted to the first side by one tooth part23and the like in the circumferential direction with respect to the tooth part23and the like on which the adhesion part41is disposed in the layer formed by the second type of adhesion part41. Then, the layer by the first type of adhesion part41, the layer by the second type of adhesion part41, and the layer by the third type of adhesion part41are disposed in order from the first side to the second side in the stacking direction. In other words, the shapes of the layers formed by the adhesion part41in the plan view are the same at a two-layer interval. When 12 or more electrical steel sheets40are stacked in the stator core21, the stator core21is configured as follows. That is, another electrical steel sheet40A is stacked next to the electrical steel sheet40J. Hereinafter, the other electrical steel sheets40B to40J are stacked in this order at positions adjacent to the second side in the stacking direction with respect to the other electrical steel sheet40A. However, when another electrical steel sheet40A is stacked next to the electrical steel sheet40J, the other electrical steel sheet40A is disposed in a state in which it rotates around the central axis O with respect to the electrical steel sheet40J so that the tooth part23C of the other electrical steel sheet40A overlaps the tooth part23A of the electrical steel sheet40J. TABLE 223A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘∘∘∘40B∘∘∘∘∘∘40C∘∘∘∘∘∘40D∘∘∘∘∘∘40E∘∘∘∘∘∘40F∘∘∘∘∘∘40G∘∘∘∘∘∘40H∘∘∘∘∘∘40I∘∘∘∘∘∘40J∘∘∘∘∘∘ A case of the stator core21in which N=7 (a prime number) is shown inFIGS.12to21and Table 3. In this case, in some tooth parts23among the plurality of tooth parts23arranged in the circumferential direction, the adhesion parts41are provided so that the arrangement regions overlap at a seven-layer interval in a plan view seen in the stacking direction. In Table 3, a portion marked with ∘ indicates the tooth part23on which the adhesion part41is disposed and the outer portion of the tooth part23in the radial direction in the core back part22on which the adhesion part41is disposed (the tooth part23and the like). When N=7 (a prime number), as shown inFIG.12and Table 3, in the electrical steel sheets40A and40I, the adhesion part41is provided on the surface23aof each of the tooth parts23of an eleventh group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the eleventh group in the core back part22. The tooth parts23of the eleventh group referred to here mean the tooth parts23A,23I, and23Q. Further, as shown inFIG.13and Table 3, in the electrical steel sheets40B and40J, the adhesion part41is provided on the surface23aof each of the tooth parts23of a twelfth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the twelfth group in the core back part22. The tooth parts23of the eleventh group referred to here mean the tooth parts23B,23J, and23R. Further, as shown inFIG.14and Table 3, in the electrical steel sheet40C, the adhesion part41is provided on the surface23aof each of the tooth parts23of a thirteenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the thirteenth group in the core back part22. The tooth parts23of the thirteenth group referred to here mean the tooth parts23C and23K. Further, as shown inFIG.15and Table 3, in the electrical steel sheet40D, the adhesion part41is provided on the surface23aof each of the tooth parts23of a fourteenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the fourteenth group in the core back part22. The tooth parts23of the fourteenth group referred to here mean the tooth parts23D and23L. Further, as shown inFIG.16and Table 3, in the electrical steel sheet40E, the adhesion part41is provided on the surface23aof each of the tooth parts23of a fifteenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the fifteenth group in the core back part22. The tooth parts23of the fifteenth group referred to here mean the tooth parts23E and23M. Further, as shown inFIG.17and Table 3, in the electrical steel sheet40F, the adhesion part41is provided on the surface23aof each of the tooth parts23of a sixteenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the sixteenth group in the core back part22. The tooth parts23of the sixteenth group referred to here mean the tooth parts23F and23N. Further, as shown inFIG.18and Table 3, in the electrical steel sheet40G, the adhesion part41is provided on the surface23aof each of the tooth parts23of a seventeenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the seventeenth group in the core back part22. The tooth parts23of the seventeenth group referred to here mean the tooth parts23G and23O. Further, as shown inFIG.19and Table 3, in the electrical steel sheet40H, the adhesion part41is provided on the surface23aof each of the tooth parts23of an eighteenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the eighteenth group in the core back part22. The tooth parts23of the eighteenth group referred to here mean the tooth parts23H and23P. Further, as shown inFIG.20and Table 3, in the electrical steel sheet40I, the adhesion part41is provided on the surface23aof each of the tooth parts23of a nineteenth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the nineteenth group in the core back part22. The tooth parts23of the nineteenth group referred to here mean the tooth parts23I and23Q. Further, as shown inFIG.21and Table 3, in the electrical steel sheet40G, the adhesion part41is provided on the surface23aof each of the tooth parts23of a twentieth group which will be described later and the surface22aof the radial outer portion of each of the tooth parts23of the twentieth group in the core back part22. The tooth parts23of the twentieth group referred to here mean the tooth parts23J and23R. In this example, 10 types of layers formed by the adhesion parts41having different shapes in a plan view are provided in the stator core21. The layers formed by the 10 types of adhesion parts41correspond from the tooth parts23of the eleventh group to the tooth parts23of the twentieth group. In all the layers formed by the 10 types of adhesion parts41, the adhesion parts41are disposed on the tooth parts23and the like at intervals of one, seven, or nine tooth parts23in the circumferential direction. A difference between the tooth parts23in which the adhesion parts41are provided between the layers by the 10 types of adhesion parts41is the same as in the case of N=1 and 2, and the description thereof will be omitted. When 12 or more electrical steel sheets40are stacked in the stator core21, the stator core21is configured as follows. That is, another electrical steel sheet40A is stacked next to the electrical steel sheet40J. Hereinafter, other electrical steel sheets40B to40J are stacked in this order at positions adjacent to the second side in the stacking direction with respect to the other electrical steel sheet40A. However, when the other electrical steel sheet40A is stacked next to the electrical steel sheet40J, the other electrical steel sheet40A is disposed at a state in which it rotates around the central axis O with respect to the electrical steel sheet40J so that the tooth part23K of the other electrical steel sheet40A overlaps the tooth part23A of the electrical steel sheet40J. TABLE 323A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘40B∘∘∘40C∘∘40D∘∘40E∘∘40F∘∘40G∘∘40H∘∘40I∘∘40J∘∘ Here, a modified example in the case of the stator core21in which N=7 will be described with reference to Table 4. In the stator core21of this modified example, in addition to the configuration of the stator core21shown in the example of Table 3, the adhesion parts41are disposed at the following two locations. Specifically, the adhesion parts41are respectively disposed on the tooth part23A and the like of the electrical steel sheet40I and the tooth part23B and the like of the electrical steel sheet40J. When 12 or more electrical steel sheets40are stacked in the stator core21of the modified example, they are basically stacked in the same manner as in the stator core21shown in the example of Table 3. However, when another electrical steel sheet40A is stacked next to the electrical steel sheet40J, the other electrical steel sheet40A is disposed in a state in which it rotates around the central axis O with respect to the electrical steel sheet40J so that the tooth part23G of the other electrical steel sheet40A overlaps the tooth part23A of the electrical steel sheet40J. TABLE 423A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘40B∘∘∘40C∘∘40D∘∘40E∘∘40F∘∘40G∘∘40H∘∘40I∘∘∘40J∘∘∘ Here, it can be said that the stator core21shown in the above-described examples of Tables 1 and 2 has the following first and second configurations relating to the adhesion part41. First configuration: a configuration in which the adhesion parts41are disposed at equal intervals in the stacking direction (at intervals of the equal number of layers in the stacking direction) over the entire length of the stator core21in the stacking direction in one of the plurality of tooth parts23arranged in the circumferential direction. Second configuration: a configuration in which the adhesion parts41are disposed at equal intervals in the circumferential direction (at intervals of the equal number of tooth parts23in the circumferential direction) over the entire circumference of the stator core21in one of the layers formed by the plurality of adhesion parts41arranged in the stacking direction. For example, in the stator core21shown in the example of Table 3, when the number of electrical steel sheets40included in the stator core21is larger (for example, when 21 electrical steel sheets40are provided), the stator core21may have the first configuration. In this case, the electrical steel sheets40after the twelfth electrical steel sheet40are stacked as described above. In order to examine the first configuration and the second configuration in detail, a first interval and a second interval are newly defined. The first interval is an interval set for each of the tooth parts23A to23R of the electrical steel sheet40. The second interval is an interval set for each of the layers by each of the adhesion parts41. The first interval is an interval indicating by how many layers the adhesion parts41in which the arrangement regions thereof overlap each other when seen in the stacking direction are separated from each other in a target tooth parts23. For example, in Table 1, attention is paid to the tooth part23A. In the tooth part23A, the adhesion parts41in which the arrangement regions thereof overlap each other when seen in the stacking direction are disposed at a one-layer interval over the entire length of the stator core21in the stacking direction. Thus, in the tooth part23A, the first interval is 1 over the entire length of the stator core21in the stacking direction. The second interval is an interval indicating how many tooth parts23on which the adhesion part41is not disposed are disposed between the circumferential directions of the other adhesion parts41adjacent to each other in the circumferential direction in the layer formed by one target adhesion part41. For example, in Table 1, attention is paid to the layer formed by the adhesion part41corresponding to the electrical steel sheet40A. In the layer formed by the adhesion part41corresponding to the electrical steel sheet40A, one tooth part23is disposed between the circumferential directions of the other adhesion parts41adjacent to each other in the circumferential direction over the entire circumference of the stator core21. Thus, in the layer formed by the adhesion part41corresponding to the electrical steel sheet40A, the second interval is 1 over the entire circumference of the stator core21. The first configuration and the second configuration can be expressed using the first interval and the second interval as follows. First configuration: a configuration in which the first intervals are equal to each other over the entire length of the stator core21in the stacking direction in one of the plurality of tooth parts23arranged in the circumferential direction. Second configuration: a configuration in which the second intervals are equal to each other over the entire circumference of the stator core21in one of the layers formed by the plurality of adhesion parts41arranged in the stacking direction. In the stator core21of the example shown in Table 1, in all the tooth parts23, the first interval is 1 over the entire length of the stator core21in the stacking direction. In all the layers formed by the adhesion parts41, the second interval is 1 over the entire circumference of the stator core21. The stator core21includes the first configuration and the second configuration. In the stator core21of the example shown in Table 2, in all the tooth parts23, the first interval is 2 over the entire length of the stator core21in the stacking direction. In all the layers formed by the adhesion parts41, the second interval is 2 over the entire circumference of the stator core21. The stator core21includes the first configuration and the second configuration. In the stator core21of the example shown in Table 3, the first interval is 7 in the tooth parts23I,23J,23Q, and23R. The tooth parts23do not have the first configuration because there is only one first interval. The first interval for the tooth parts23A to23H and23K to23P is not specified because there is no other adhesion parts41in which the arrangement regions thereof overlap each other when seen in the stacking direction. Since the first interval is not defined for these tooth parts23, the first configuration is not provided. The second intervals in the layers by the adhesion parts41corresponding to the electrical steel sheets40A and40B are 7, 7, and 1. The second intervals in the layers by the adhesion parts41corresponding to the electrical steel sheets40C to40J are 7 and 9. In the stator core21of this example, all the layers formed by the plurality of adhesion parts41do not have the second configuration. As described above, in the stator core21shown in the example of Table 3, when the number of electrical steel sheets40included in the stator core21is larger, the stator core21may have the first configuration. Similar to the stator core21of the example shown in Table 3, the stator core21of the example shown in Table 4 does not have the first configuration and the second configuration. However, the stator core21may not have the first configuration and the second configuration as in the example of stator cores21shown in Tables 3 and 4. The stator core21may not have one of the first configuration and the second configuration and may not have both of them. In the following, the stator core21which does not have the first configuration and the second configuration will be described with reference to Tables 5 and 6. In the stator core21of the examples shown in Tables 5 and 6, 11 electrical steel sheets40(400and40A to40J) are stacked. The electrical steel sheet400is not shown in the tables. In Tables 5 and 6, a portion marked with ∘ indicates the tooth part23B and the like on which the adhesion part41is disposed. Instead of the stator core21having the first configuration, for example, the following third configuration or fifth configuration may be provided. Third configuration: a configuration in which the arrangement regions of the adhesion parts41overlap each other at an interval of different prime number layers in a plan view seen in the stacking direction in a part of the region of the stator core21in the stacking direction in one of the plurality of tooth parts23arranged in the circumferential direction. In other words, the third configuration is a configuration in which the first intervals adjacent to each other in the stacking direction are prime numbers different from each other in a part of the region of the stator core21in the stacking direction in one of the plurality of tooth parts23arranged in the circumferential direction. Fifth configuration: a configuration in which the arrangement regions of the adhesion parts41overlap each other at an interval of different prime number layers over the entire length of the stator core21in the stacking direction, in a plan view in the stacking direction, in one of the plurality of tooth parts23arranged in the circumferential direction. In other words, the fifth configuration is a configuration in which the first intervals adjacent to each other in the stacking direction are prime numbers different from each other over the entire length of the stator core21in the stacking direction in one of the plurality of tooth parts23arranged in the circumferential direction. Further, instead of the stator core21having the second configuration, for example, the following fourth configuration or sixth configuration may be provided. Fourth configuration: a configuration in which the number of tooth parts23between the adhesion parts41adjacent to each other in the circumferential direction is a prime number different from each other in a part of the region of the stator core21in the circumferential direction in one of the layers formed by the plurality of adhesion parts41arranged in the stacking direction. In other words, the fourth configuration is a configuration in which the second intervals adjacent to each other in the circumferential direction are prime numbers different from each other in a part of the region of the stator core21in the circumferential direction in one of the layers formed by the plurality of adhesion parts41arranged in the stacking direction. Sixth configuration: a configuration in which the number of tooth parts23between the adhesion parts41adjacent to each other in the circumferential direction is a prime number different from each other over the entire circumference of the stator core21in one of the layers formed by the plurality of adhesion parts41arranged in the stacking direction. In other words, the sixth configuration is a configuration in which the second intervals adjacent to each other in the circumferential direction are prime numbers different from each other over the entire circumference of the stator core21in one of the layers formed by the plurality of adhesion parts41arranged in the stacking direction. In the following, the stator core21for each of cases will be described while attention is paid to the above configuration. (Case 1) The stator core21shown in an example of Table 5 will be described. In the stator core21of Case 1, four adhesion parts41are disposed in the layer formed by the adhesion parts41corresponding to the electrical steel sheet40A. In this layer, the four adhesion parts41are disposed on the tooth parts23A,23E,23K, and23O. Then, in each of the layers formed by the adhesion parts41corresponding to the electrical steel sheets40B to40D, each of the tooth parts23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. In each of the layers formed by the adhesion parts41corresponding to the electrical steel sheets40E and40F, each of the tooth parts23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. Further, in each of the layers of the adhesion parts41corresponding to the electrical steel sheets40E and40F, the number of the adhesion parts41disposed is reduced to three. Specifically, in the layer formed by the adhesion part41corresponding to the electrical steel sheet40E, when the adhesion part41tries to shift from the tooth part23R to the first side in the circumferential direction, the adhesion part41is not shifted to the tooth part23A but disappears. In each of the layers formed by the adhesion parts41corresponding to the electrical steel sheets40G and40H, each of the tooth parts23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. Further, in each of the layers of the adhesion parts41corresponding to the electrical steel sheets40G and40H, the number of the adhesion parts41is increased to four. Specifically, in the layer formed by the adhesion part41corresponding to the electrical steel sheet40G, the adhesion part41is disposed on the tooth part23A. In each of the layers formed by the adhesion parts41corresponding to the electrical steel sheets40I and40J, each of the tooth parts23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. Further, in each of the layers of the adhesion parts41corresponding to the electrical steel sheets40I and40J, the number of the adhesion parts41disposed is reduced to three again. Specifically, in the layer formed by the adhesion part41corresponding to the electrical steel sheet40I, when the adhesion part41tries to shift from the tooth part23R to the first side in the circumferential direction, the adhesion part41is not shifted to the tooth part23A but disappears. TABLE 523A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘∘40B∘∘∘∘40C∘∘∘∘40D∘∘∘∘40E∘∘∘40F∘∘∘40G∘∘∘∘40H∘∘∘∘40I∘∘∘40J∘∘∘ In such a stator core21, it can be said that some of the layers formed by the plurality of adhesion parts41have the fourth configuration and the remaining layers have the sixth configuration. That is, in the layers having the four adhesion parts41, for example, the layer corresponding to the electrical steel sheet40A among the layers formed by the adhesion parts41, the second intervals are arranged in the order of 3, 5, 3, and 3 toward the first side in the circumferential direction. These layers have the fourth configuration. Further, in the layers having the three adhesion parts41, for example, the layer corresponding to the electrical steel sheet40E among the layers formed by the adhesion parts41, the second intervals are arranged in the order of 3, 5, and 7 toward the first side in the circumferential direction. These layers have the sixth configuration. The stator core21of Case 1 does not have the third configuration and the fifth configuration. (Case 2) Next, the stator core of an example shown in Table 6 will be described. In the stator core21of Case 2, six adhesion parts41are disposed in the layer formed by the adhesion parts41corresponding to the electrical steel sheet40A. In this layer, a total of six adhesion parts41are disposed on the tooth parts23A,23D,23G,23J,23M, and23P. Then, in the layers formed by the adhesion parts41corresponding to the electrical steel sheets40B and40C, each of the tooth parts23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. In each of the layers by the adhesion parts41corresponding to the electrical steel sheets40D to40I, each of the tooth parts23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. Further, in each of the layers of the adhesion parts41corresponding to the electrical steel sheets40D to40I, the number of the adhesion parts41disposed is reduced to three. Specifically, in the layer formed by the adhesion part41corresponding to the electrical steel sheet40D, when the adhesion part41tries to shift from the tooth parts23F,23L, and23R to the first side in the circumferential direction, the adhesion part41is not shifted to the tooth parts23G,23M, and23A but disappears. In each of the layers by the adhesion parts41corresponding to the electrical steel sheet40J, the tooth part23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. Further, the number of the adhesion parts41is increased to 6 in each of the layers formed by the adhesion parts41corresponding to the electrical steel sheet40J. Specifically, in the layer formed by the adhesion parts41corresponding to the electrical steel sheet40J, the adhesion parts41are disposed on the tooth parts23A,23G, and23M. TABLE 623A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘∘∘∘40B∘∘∘∘∘∘40C∘∘∘∘∘∘40D∘∘∘40E∘∘∘40F∘∘∘40G∘∘∘40H∘∘∘40I∘∘∘40J∘∘∘∘∘∘ It can be said that such a stator core21has the fifth configuration in some of the tooth parts23among the plurality of tooth parts23arranged in the circumferential direction. That is, the tooth parts23A,23D,23G,23J,23M, and23P in which the three arrangement regions thereof overlap each other in a plan view seen in the stacking direction will be described. For example, in the tooth part23A, the first intervals adjacent to each other in the stacking direction are disposed in the order of 5 and 2 from the first side to the second side in the stacking direction over the entire length of the stator core21in the stacking direction. For example, in the tooth part23D, the first intervals adjacent to each other in the stacking direction are disposed in the order of 2 and 5 from the first side to the second side in the stacking direction over the entire length of the stator core21in the stacking direction. The tooth parts23A,23D,23G,23J,23M, and23P have the fifth configuration. The stator core21of Case 2 does not have the third configuration, the fourth configuration, and the sixth configuration. In the tooth part23A, the first intervals are 5 and 2 from the first side to the second side in the stacking direction. However, for example, in the tooth part23A, the first intervals may be 5, 2, 5, 2, . . . from the first side to the second side in the stacking direction. Then, in the tooth part23B, the first intervals may be 5, 2, 2, 5, . . . from the first side to the second side in the stacking direction. In this way, the first interval may be changed for each of the tooth parts23. (Case 3) Next, the stator core of an example shown in Table 7 will be described. In the stator core21of the example shown in Table 7, 16 electrical steel sheets40(400and40A to40O) are stacked. The electrical steel sheet400is not shown in the table. In the stator core21of Case 3, four adhesion parts41are disposed in the layer formed by the adhesion parts41corresponding to the electrical steel sheet40A. In this layer, the four adhesion parts41are disposed on the tooth parts23A,23D,23J, and23M. Then, in each of the layers formed by the adhesion parts41corresponding to the electrical steel sheets40B to40O, the tooth part23on which the adhesion part41is disposed is shifted to the first side in the circumferential direction by one tooth part with respect to the layers adjacent to the first side in the stacking direction. TABLE 723A23B23C23D23E23F23G23H23I23J23K23L23M23N23O23P23Q23R40A∘∘∘∘40B∘∘∘∘40C∘∘∘∘40D∘∘∘∘40E∘∘∘∘40F∘∘∘∘40G∘∘∘∘40H∘∘∘∘40I∘∘∘∘40J∘∘∘∘40K∘∘∘∘40L∘∘∘∘40M∘∘∘∘40N∘∘∘∘40O∘∘∘∘ It can be said that such a stator core21has the fifth configuration in all the tooth parts23arranged in the circumferential direction. That is, the tooth parts23A to23C and23J to23L in which the three arrangement regions thereof overlap each other in a plan view seen in the stacking direction will be described. In the tooth parts23, the first intervals adjacent to each other in the stacking direction are arranged in the order of 5 and 2 from the first side to the second side in the stacking direction over the entire length of the stator core21in the stacking direction. Next, the tooth parts23G to23I and23P to23R in which the three arrangement regions thereof overlap each other in a plan view seen in the stacking direction will be described. In the tooth parts23, the first intervals adjacent to each other in the stacking direction are arranged in the order of 2, 5 from the first side to the second side in the stacking direction over the entire length of the stator core21in the stacking direction. Next, the tooth parts23D to23F and23M to23O in which the four arrangement regions thereof overlap each other in a plan view seen in the stacking direction will be described. In the tooth parts23, the first intervals adjacent to each other in the stacking direction are arranged in the order of 2, 5 and 2 from the first side to the second side in the stacking direction over the entire length of the stator core21in the stacking direction. Further, it can be said that such a stator core21has the sixth configuration in all layers of the layer formed by the plurality of adhesion parts41. That is, in all the layers formed by the adhesion parts41, the second intervals are arranged in the order of 2, 5, 2, and 5 toward the first side in the circumferential direction. The stator core21of Case 3 does not have the third configuration and the fourth configuration. Here, a configuration of the stator core21in which the adhesion part41is disposed to have at least one of the third configuration and the fourth configuration is hereinafter referred to as a first unequal interval configuration. A configuration of the stator core21in which the adhesion part41is disposed to have one of the fifth configuration and the sixth configuration is hereinafter referred to as a second unequal interval configuration. A configuration of the stator core21in which the adhesion part41is disposed to have both the fifth configuration and the sixth configuration is hereinafter referred to as a third unequal interval configuration. The stator core21having the first unequal interval configuration, the second unequal interval configuration, or the third unequal interval configuration can further prevent resonance frequencies of the electric motor and the laminated core from matching. In the stator core21of Case 1, since some of the layers formed by the plurality of adhesion parts41have the fourth configuration, the stator core21of this example has the fourth configuration. Since the remaining layers of the layers formed by the plurality of adhesion parts41have the sixth configuration, the stator core of this example has the sixth configuration. The stator core21of Case 1 does not have the third configuration and the fifth configuration. Therefore, the stator core21of Case 1 has the first unequal interval configuration because it has the fourth configuration of the third configuration and the fourth configuration. The stator core21of Case 1 has only the sixth configuration of the fifth configuration and the sixth configuration. Therefore, the stator core21of this example has the second unequal interval configuration, but does not have the third unequal interval configuration. The stator core21of the case 2 has the fifth configuration. The stator core21of Case 2 does not have the third configuration, the fourth configuration, and the sixth configuration. Therefore, the stator core21of this example does not have the first unequal interval configuration because it does not have both the third configuration and the fourth configuration. The stator core21of this example has only the fifth configuration of the fifth configuration and the sixth configuration. Therefore, the stator core21of this example has the second unequal interval configuration, but does not have the third unequal interval configuration. The stator core21of Case 3 does not have the third configuration and the fourth configuration, but has the fifth configuration and the sixth configuration. Therefore, the stator core21of this example does not have the first unequal interval configuration and the second unequal interval configuration, but has the third unequal interval configuration. In the first unequal interval configuration to the third unequal interval configuration, the effect of preventing the resonance frequencies of the electric motor and the laminated core (the stator core) from matching is greater in the second unequal interval configuration than in the first unequal interval configuration. This is because, in the second unequal interval configuration, the arrangement regions of the adhesion parts41overlap each other at an interval of different prime number layers over the entire length in the stacking direction, or the number of adhesion parts41is a prime number in which the numbers of tooth parts23between adhesion parts41adjacent to each other in the circumferential direction over the entire circumference are different from each other. Therefore, this is because the second unequal interval configuration improves the non-uniformity of the adhesion part of the laminated core as compared with the first unequal interval configuration. This effect is greater in the third unequal interval configuration than in the second unequal interval configuration. This is because, in the third unequal interval configuration, the arrangement regions of the adhesion parts41overlap each other at an interval of different prime number layers over the entire length in the stacking direction, and also the adhesion parts41are a prime number in which the number of tooth parts23between the adhesion parts41adjacent to each other in the circumferential direction over the entire circumference is different from each other. Therefore, this is because the third unequal interval configuration further improves the non-uniformity of the adhesion part of the laminated core as compared with the second unequal interval configuration. For the adhesion part41, for example, a thermosetting adhesive by polymer bonding or the like is used. As a composition of the adhesive, (1) an acrylic-based resin, (2) an epoxy-based resin, (3) a composition containing an acrylic-based resin and an epoxy-based resin, and the like can be applied. As the adhesive, a radical polymerization type adhesive or the like can also be used in addition to the thermosetting adhesive. From the viewpoint of productivity, a room temperature curing type (room temperature adhesive type) adhesive is desirable. The room temperature curing type adhesive cures at 20° C. to 30° C. In addition, in this specification, a numerical range represented by using “to” means a range including numerical values before and after “to” as the lower limit value and the upper limit value. As the room temperature curing type adhesive, an acrylic-based adhesive is preferable. Typical acrylic-based adhesives include a second generation acrylic-based adhesive (SGA) and the like. An anaerobic adhesive, an instant adhesive, and an elastomer-containing acrylic-based adhesive can be used as long as the effects of the present invention are not impaired. The adhesive referred to here refers to a state before curing. The adhesive becomes the adhesion part41when the adhesive is cured. An average tensile modulus of elasticity E of the adhesion part41at room temperature (20° C. to 30° C.) is in a range of 1500 MPa to 4500 MPa. When the average tensile modulus of elasticity E of the adhesion part41is less than 1500 MPa, there is a problem that a rigidity of the laminated core is lowered. Therefore, a lower limit value of the average tensile modulus of elasticity E of the adhesion part41is 1500 MPa, and more preferably 1800 MPa. On the contrary, when the average tensile modulus of elasticity E of the adhesion part41exceeds 4500 MPa, there is a problem that the insulation coating formed on the surface of the electrical steel sheet40is peeled off. Therefore, an upper limit value of the average tensile modulus of elasticity E of the adhesion part41is 4500 MPa, and more preferably 3650 MPa. The average tensile modulus of elasticity E is measured by a resonance method. Specifically, the tensile modulus of elasticity is measured based on JIS R 1602:1995. More specifically, first, a sample for measurement (not shown) is produced. This sample is obtained by adhering two electrical steel sheets40with an adhesive to be measured and curing the adhesive to form the adhesion part41. When the adhesive is a thermosetting type, the curing is performed by heating and pressurizing under heating and pressurizing conditions in an actual operation. On the other hand, when the adhesive is a room temperature curing type, it is performed by pressurizing at room temperature. Then, the tensile modulus of elasticity of this sample is measured by the resonance method. As described above, a method for measuring the tensile modulus of elasticity by the resonance method is performed based on JIS R 1602: 1995. After that, the tensile modulus of elasticity of the adhesion part41alone can be obtained by removing an influence of the electrical steel sheet40itself from the tensile modulus of elasticity (a measured value) of the sample by calculation. The tensile modulus of elasticity obtained from the sample in this way is equal to an average value of all the stator cores21which are the laminated cores. Thus, this value is regarded as the average tensile modulus of elasticity E. The composition is set so that the average tensile modulus of elasticity E hardly changes at a stacking position in the stacking direction or at a circumferential position around the central axis of the stator core21. Therefore, the average tensile modulus of elasticity E can be set to a value obtained by measuring the cured adhesion part41at an upper end position of the stator core21. As the adhering method using the thermosetting adhesive, for example, a method in which an adhesive is applied to the electrical steel sheet40and then adhered by one of heating and press-stacking, or both of them can be adopted. A heating unit may be, for example, one of heating in a high temperature bath or an electric furnace, a method of directly energizing, and the like, and may be any one. In order to obtain stable and sufficient adhesion strength, the thickness of the adhesion part41is preferably 1 μm or more. On the other hand, when the thickness of the adhesion part41exceeds 100 μm, an adhesion force is saturated. Further, as the adhesion part41becomes thicker, the space factor decreases, and the magnetic properties such as iron loss of the laminated core decrease. Therefore, the thickness of the adhesion part41is 1 μm or more and 100 μm or less. The thickness of the adhesion part41is more preferably 1 μm or more and 10 μm or less. In the above description, the thickness of the adhesion part41means an average thickness of the adhesion part41. The average thickness of the adhesion part41is more preferably 1.0 μm or more and 3.0 μm or less. When the average thickness of the adhesion part41is less than 1.0 sufficient adhesion force cannot be ensured as described above. Therefore, a lower limit value of the average thickness of the adhesion part41is 1.0 μm, and more preferably 1.2 μm. On the contrary, when the average thickness of the adhesion part41becomes thicker than 3.0 μm, problems such as a large increase in a strain amount of the electrical steel sheet40due to a shrinkage during thermosetting occur. Therefore, an upper limit value of the average thickness of the adhesion part41is 3.0 μm, and more preferably 2.6 μm. The average thickness of the adhesion part41is an average value of all the laminated cores. An average thickness of the adhesion part41hardly changes at the stacking position in the stacking direction and a circumferential position around the central axis of the stator core21. Therefore, the average thickness of the adhesion part41can be set as an average value of numerical values measured at 10 or more points in the circumferential direction at an upper end position of the stator core21. The average thickness of the adhesion part41can be adjusted, for example, by changing an amount of adhesive applied. Further, in the case of the thermosetting adhesive, the average tensile modulus of elasticity E of the adhesion part41may be adjusted, for example, by changing one or both of heating and pressurizing conditions applied at the time of adhesion and a type of curing agent. In the present embodiment, the plurality of electrical steel sheets40forming the rotor core31are fixed to each other by a fastening42(a dowel) (seeFIG.1). However, the plurality of electrical steel sheets40forming the rotor core31may be stacked to each other by the adhesion part41. The laminated cores such as the stator core21and the rotor core31may be formed by so-called turn-stacking. The electric motor10can rotate at a rotation speed of 1000 rpm by applying an excitation current having an effective value of 10 A and a frequency of 100 Hz to each of the phases, for example. As described above, in the stator core21(the laminated core) according to the present embodiment, the adhesion part41which adheres the electrical steel sheets40is disposed between the electrical steel sheets40adjacent to each other in the stacking direction. The adhesion part41partially adheres the electrical steel sheets40adjacent to each other in the stacking direction. The adhesion parts41adjacent to each other in the stacking direction have different arrangement regions in a plan view seen in the stacking direction. With such a configuration, as compared with a case in which the arrangement regions of the adhesion parts adjacent to each other in the stacking direction overlap each other in the plan view seen in the stacking direction, the least common multiple of the adhesion part adjacent to a predetermined adhesion part in the stacking direction and the adhesion part adjacent to the predetermined adhesion part in the circumferential direction becomes large. Therefore, the resonance frequency of the stator core21can be increased. As a result, it is possible to prevent the resonance frequencies of the electric motor10and the stator core21from matching. Therefore, the stator core21is less likely to vibrate, and the motor characteristics of the stator core21can be improved. Generally, the adhesive shrinks as it cures. Therefore, compressive stress is applied to the electrical steel sheet as the adhesive cures. When the compressive stress is applied, the electrical steel sheet is strained. In the stator core21(the laminated core) according to the present embodiment, the adhesion part41is provided on at least one of the surface22aof the core back part22and the surface23aof the tooth part23in the electrical steel sheet40. Thus, a region in which the adhesion part41is provided is reduced as compared with a case in which the adhesion part41is provided on the entire surface of the stacking surface of the electrical steel sheet40. Therefore, an amount of strain applied to the electrical steel sheet40by the adhesion part41is reduced. Therefore, deterioration of the magnetic properties of the stator core21can be curbed. In the stator core21(the laminated core) according to the present embodiment, the adhesion parts41are provided at an N-layer interval (N is a natural number) so that the arrangement regions thereof overlap each other in a plan view seen in the stacking direction. Therefore, since the adhesion parts adjacent to each other in the stacking direction have different arrangement regions in the plan view seen in the stacking direction, it is possible to prevent the resonance frequencies of the electric motor10and the stator core21from matching. For example, in a plan view seen in the stacking direction, the strain generated in the electrical steel sheet40becomes uniform in the stacking direction in contrast to a case in which the arrangement regions of the adhesion parts overlap each other in the stacking direction at a non-constant interval. Therefore, it is possible to curb biasing of the strain generated in the electrical steel sheet40due to the curing of the adhesive in the stator core21as a whole. Specifically, the adhesion parts41are provided at a one-layer interval so that the arrangement regions thereof overlap each other in a plan view seen in the stacking direction. Thus, it is possible to curb local concentration of the electrical steel sheets40joined by adhesion on a part of the stator core21in the stacking direction. Therefore, the electrical steel sheets40joined by adhesion can be dispersed in the stacking direction. Therefore, it is possible to prevent the resonance frequencies of the electric motor10and the stator core21from matching. As a result, the motor characteristics of the stator core21can be further improved. Further, the adhesion parts41are provided at a prime number-layer interval so that the arrangement regions thereof overlap each other in a plan view seen in the stacking direction. Since the number of divisors of N which is a prime number is small, the least common multiple of the adhesion part adjacent to a predetermined adhesion part in the stacking direction and the adhesion part adjacent to the predetermined adhesion part in the circumferential direction becomes large. Therefore, the resonance frequency of the stator core21can be increased. As a result, it is possible to prevent the resonance frequencies of the electric motor10and the stator core21from matching. Therefore, the motor characteristics of the stator core21can be further improved. The stacking surface of the electrical steel sheet40located at one end in the stacking direction among the plurality of electrical steel sheets40is entirely adhered to the stacking surface of the electrical steel sheets40adjacent to each other in the stacking direction. Further, the stacking surface of the electrical steel sheet40located at the other end in the stacking direction among the plurality of electrical steel sheets40is entirely adhered to the stacking surface of the electrical steel sheets40adjacent to each other in the stacking direction. Therefore, separation of the stacking surface of the electrical steel sheet40located at one end in the stacking direction and the stacking surface of the electrical steel sheet40adjacent to this surface in the stacking direction among the electrical steel sheets40from each other in the stacking direction is curbed at both an outer peripheral edge and a central portion of the surface. Therefore, it is possible to curb generation of vibration between the surfaces adjacent to each other in the stacking direction. Similarly, in the electrical steel sheet40located at the other end in the stacking direction among the electrical steel sheets40, it is also possible to curb the generation of vibration between the surfaces adjacent to each other in the stacking direction. The electric motor10according to the present embodiment includes the stator core21(the laminated core) according to the present embodiment. Therefore, the motor characteristics of the electric motor10can be improved. The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the purpose of the present invention. Here, as shown inFIG.3, in the stator core21, an outer one of the plurality of electrical steel sheets40in the stacking direction is referred to as an upper end portion (a first end portion)71. In the stator core21, the other outer one of the plurality of electrical steel sheets40in the stacking direction is referred to as a lower end portion (a second end portion)72. As shown inFIG.22, in the stator core21, the adhesion part41may be provided on the entire surface of the stacking surface (the surface22aof the core back part22) of the electrical steel sheet40located at the upper end portion71. Further, the surface22aof the core back part22of the electrical steel sheet40may be entirely adhered to the surface22aof the core back part22of the electrical steel sheets40adjacent to each other in the stacking direction. Further, as shown inFIG.22, in the stator core21, the adhesion part41may be provided on the entire surface of the stacking surface (the surface23aof the tooth part23) of the electrical steel sheet40located at the upper end portion71. Further, the surface23aof the tooth part23of the electrical steel sheet40may be entirely adhered to the surface23aof the tooth part23of the electrical steel sheets40adjacent to each other in the stacking direction. Similarly, as shown inFIG.22, in the stator core21, the adhesion part41may be provided on the entire surface of the stacking surface (the surface22aof the core back part22) of the electrical steel sheet40located at the lower end portion72. Further, the surface22aof the core back part22of the electrical steel sheet40may be entirely adhered to the surface22aof the core back part22of the electrical steel sheets40adjacent to each other in the stacking direction. Further, as shown inFIG.22, in the stator core21, the adhesion part41may be provided on the entire surface of the stacking surface (the surface23aof the tooth part23) of the electrical steel sheet40located at the lower end portion72. Further, the surface23aof the tooth part23of the electrical steel sheet40may be entirely adhered to the surface23aof the tooth part23of the electrical steel sheets40adjacent to each other in the stacking direction. According to the above-described configuration, in the stator core21, the stacking surface of the electrical steel sheet40located at the upper end portion71in the stacking direction of the stator core21among the plurality of electrical steel sheets40is entirely adhered to the stacking surface of the electrical steel sheets40adjacent to each other in the stacking direction. Further, the stacking surface of the electrical steel sheet40located at the lower end portion (the second end portion)72of the stator core21in the stacking direction among the plurality of electrical steel sheets40is entirely adhered to the stacking surface of the electrical steel sheets40adjacent to each other in the stacking direction. Thus, it is possible to curb the bias of the strain generated in the electrical steel sheet40due to the adhesion part41. Therefore, it is possible to curb the bias of the strain generated in the entire stator core21. In other words, in all the sets of the electrical steel sheets40stacked in the stacking direction, it is not necessary that the arrangement regions do not overlap each other in a plan view. At least in some sets of the electrical steel sheets40, the arrangement regions may not overlap each other in the plan view. The shape of the stator core is not limited to the form shown in the above-described embodiment. Specifically, dimensions of an outer diameter and an inner diameter of the stator core, the stacking thickness, the number of slots, a dimensional ratio between the circumferential direction and the radial direction of the tooth part, a dimensional ratio in the radial direction between the tooth part and the core back part, and the like can be arbitrarily designed according to the desired properties of the electric motor. In the rotor of the above-described embodiment, although a set of two permanent magnets32form one magnetic pole, the present invention is not limited thereto. For example, one permanent magnet32may form one magnetic pole, or three or more permanent magnets32may form one magnetic pole. In the above-described embodiment, although the permanent magnetic electric motor has been described as an example of the electric motor, the structure of the electric motor is not limited thereto as illustrated below, and various known structures not exemplified below can also be adopted. In the above-described embodiment, although the permanent magnetic electric motor has been described as an example of the synchronous motor, the present invention is not limited thereto. For example, the electric motor may be a reluctance motor or an electromagnet field motor (a wound-field motor). In the above-described embodiment, although the synchronous motor has been described as an example of the AC motor, the present invention is not limited thereto. For example, the electric motor may be an induction motor. In the above-described embodiment, although the AC motor has been described as an example of the electric motor, the present invention is not limited thereto. For example, the electric motor may be a DC motor. In the above-described embodiment, although the motor has been described as an example of the electric motor, the present invention is not limited thereto. For example, the electric motor may be a generator. In the above-described embodiment, although the case in which the laminated core according to the present invention is applied to the stator core is exemplified, the laminated core according to the present invention can also be applied to the rotor core. In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the purpose of the present invention, and the above-described modified examples may be appropriately combined. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a laminated core in which the motor characteristics are enhanced and an electric motor including the laminated core. Therefore, the industrial applicability is great. BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS 10Electric motor20Stator21Stator core (laminated core)22Core back part23Tooth part30Rotor31Rotor core (laminated core)32Permanent magnet33Through-hole40Electrical steel sheet41Adhesion part50Case60Rotation shaft | 80,973 |
11863018 | MODES FOR CARRYING OUT THE INVENTION First Embodiment FIG.1shows an example of a cross-sectional view of the reluctance motor of the present invention. The reluctance motor is provided with 6 magnetic poles on the stator and 4 magnetic poles on the rotor, which is also called a switched reluctance motor. A reference sign19is a stator and a reference sign1B is a rotor shaft. Reference signs1J,1K,1L, and1M show magnetic poles of the rotor, in which an angular width θBr of each rotor magnetic pole in the circumferential direction is larger than 30°, and the rotor magnetic poles are arranged at four places on the entire circumference at equal intervals. Compared with the example of the conventional reluctance motor shown inFIG.46, the circumferential angular width θBr of each of the salient poles of the rotor is different, and further, the internal shape and magnetic resistance of the rotor magnetic pole are different from those shownFIG.46. In addition, there are some differences as to the shapes and magnetic characteristics of the rotor magnetic poles. Some examples of such shapes and characteristics of the rotor magnetic poles will be described in detail later. A reference11shown inFIG.1is an A1 phase stator magnetic pole, and concentrated winding windings17and18are wound therearound as shown by broken lines. The current of each winding of this motor is a one-way current, and each winding is indicated by a current symbol. The winding17is shown by a current symbol in which X is written in a circle and is energized as a current flowing from the front side to the back side of the drawing sheet. The winding18is shown a current symbol in which a dot is written in a circle and is energized as a current flowing from the back side to the front side of the drawing sheet. Therefore, when the current is energized in such a way, the stator magnetic pole11of the A1 phase becomes an S pole. A reference sign12denotes an A1/ phase stator magnetic pole whose phase is opposite to that of the A1 phase, around which concentrated winding windings1C and1D are wound as shown by broken lines. When an A1/ phase current is supplied thereto, the A1/ phase stator magnetic pole12becomes an N pole. The phase stator magnetic poles11and12are excited at the same time, resulting in that the magnetic fluxes indicated by the arrow1E are passed through the rotor, from the lower side to the upper side of the drawing sheet, and through the stator magnetic pole12, the rotor magnetic pole1L, the rotor magnetic pole J, and to the stator magnetic pole11. Then, the magnetic fluxes go around through the back yoke. In the state ofFIG.1, torque is generated in the rotor in the counterclockwise rotation direction CCW. Reference signs13and14are B1 and B1/ phase stator magnetic poles which are provided in the same way as the A1 and A1/ phase stator magnetic poles. Excitation windings are wound around each of the B1 and B1/ phase stator poles. Similarly, reference signs15and16are C1 and C1/ phase stator magnetic poles. Excitation windings are wound around each of the C1 and C1/ phase stator magnetic poles. The circumferential width of each stator magnetic pole is 30°, and the stator magnetic poles are arranged at six locations on the entire circumference at equal intervals. The rotor magnetic poles1J,1K,1L, and1M are evenly arranged on the circumference. The rotation angle position θr of the rotor is defined by the position of the rotor magnetic pole13. As shown inFIG.1, the rotation angle position of the clockwise end of the A1 phase stator magnetic pole11is defined as the start point of the rotor. The rotor rotation angle position θr is the rotation angle from this start point to the end of the rotor magnetic pole1J in the CCW direction. The circumferential angular width Br of the salient pole of the rotor has a different rotor shape depending on the type of motor and can take various values according to the desired motor characteristics. Here,FIG.2shows an example of the characteristics required for the motor for the main-machine engine of an electric vehicle. This characteristic is also an example of the performance targeted by the reluctance motor of the present invention. The horizontal axis is the number of revolutions, and the maximum number of revolutions is 10,000 rpm. The vertical axis is torque T, which has a continuous rated torque of 33 Nm and a maximum torque of 100 Nm. The region shown by A inFIG.2is required for climbing a steep slope for the main engine of an automobile, and the large torque region of low-speed rotation is an important characteristic. Since a large current is applied, the power factor generally decreases and the copper loss increases, so that it is a thermally harsh operating area and often affects the size of the motor. The region shown by B inFIG.2is a high-speed rotation region, which is required for high-speed traveling of an automobile. Although the conventional reluctance motor can rotate, the torque pulsation becomes large, the noise becomes large, and the torque is not easily generated. The conventional magnet type synchronous motor has a problem that the power factor decreases due to the field weakening, the voltage and the current increase, and the inverter becomes large. In particular, the low-speed rotation and large torque in the region A and the constant output characteristics in the high-speed rotation in the region B may have a trade-off relationship because the amount of magnetic flux may conflict with each other in terms of motor technology. The region shown by C inFIG.2is a constant output region, and since the base rotation speed is 2,500 rpm, the maximum output is 26.18 kW. The region shown by D inFIG.2is a region frequently used in urban driving of automobiles but is a region that does not affect the size, weight, and cost of the motor and the inverter. However, it is an area where quietness is required, and noise and vibration need to be reduced. In the description of the conventional reluctance motor inFIG.47, the magnetic characteristics and the torque characteristics which are simply models of the magnetic characteristics are shown, but as shown in Patent Document 1, it becomes the torque characteristics as shown in the example ofFIG.48. The rotor rotation angle θr does not have a rectangular wavy characteristic between 0° and 30°, and the torque decreases significantly as θr approaches 30°. The cause of this torque decrease is not simple, but there Is a problem of partial magnetic saturation characteristics of the soft magnetic material, a problem of magnetic saturation of the entire magnetic path of the teeth of the stator and the back yoke, and a problem of leakage flux. The solid line inFIG.3(a)is an example of the magnetic characteristics of a soft magnetic material such as an electromagnetic steel plate. The magnetic flux density increases with the exciting current If, but the relative magnetic permeability decreases from around 1.6 [T]. Then, it is magnetically saturated near the magnetic flux density of 2.0 [T].FIG.3(b)shows the relationship between the rotor rotation angle θr shown inFIGS.46,47, and48and the magnitude φ [Wb] of the magnetic flux passing through the teeth of the stator. The rotor rotation angle θr is relatively linear up to the vicinity of 15°, and magnetic flux passes between the corner of the salient pole of the stator and the corner of the salient pole of the rotor. When the rotor rotation angle θr is around 30°, the magnetic resistance of the entire magnetic path of the stator and rotor teeth and the back yoke increases, and the increase in magnetic flux decreases. Improvements to these problems will also be described later. InFIG.48, there is a problem of noise in the vicinity of the rotor rotation angle θr of 30°. The torque decreases in the vicinity of 30°, and a negative torque is generated when it exceeds 30°. Therefore, it is necessary to reduce the exciting current of the corresponding stator magnetic pole before 30°. Further, when the rotor rotation angle position θr approaches 30°, the radial attractive force between the A-phase stator magnetic pole and the rotor magnetic pole increases. If the exciting current is sharply reduced in this state, the radial attractive force between the stator magnetic pole and the rotor magnetic pole is sharply reduced, and the back yoke portion of the stator is deformed and vibrates. As a result, a large amount of noise is generated from the back yoke portion of the motor and its surroundings. Further, as the rotor rotates, a resonance phenomenon occurs, and a large noise is generated. Further, if the torque of each phase has the torque characteristics as shown inFIG.48, the torque will pulsate greatly, and there is a problem of torque ripple. Further, if the torque of each phase decreases as shown in the vicinity of 30° inFIG.48, there is a problem that the average torque decreases. Next, as a specific operation example of the reluctance motor ofFIG.1, its operation, voltage, current, and torque will be shown and described inFIGS.4and5. This is an operation of rotating to CCW to generate CCW torque or CW torque.FIG.4(a)shows a linear development of the shape of the inner peripheral surface of the stator magnetic pole SP seen from the air gap surface between the stator and the rotor so that the circumferential direction of the CCW is the horizontal axis direction ofFIG.4. The vertical axis direction inFIG.4is the rotor axis direction.11inFIG.4is an A1 phase stator pole,12is an A1/ phase stator pole,13is a B1 phase stator pole,14is a B1/ phase stator pole,15is C1 phase stator pole, and16is a C1/ phase stator pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 30° and a rotor axial length of Ls. FIG.4(b)is the figure that the shape of the outer peripheral surface of the rotor magnetic pole RP as seen from the air gap surface is such that the circumferential direction of the CCW inFIG.1is the horizontal axis direction inFIG.4, that is, developed dinearly as the right direction on the paper surface. The value of the rotor rotation angle position θr is shown at the bottom ofFIG.4. InFIG.1, the starting point of the rotor is the rotation angle position of the clockwise end of the A1 phase stator magnetic pole11, and the rotor rotation angle position θr is from the starting point to the CCW direction end of the rotor magnetic pole13. The starting point of the rotor inFIG.4is the left end of the stator magnetic pole11on the paper. The value of the rotor rotation angle position θr at the bottom of that point is set to 0°. The rotor rotation angle position θr inFIG.4is from the start point to the right end of the rotor magnetic pole4J. InFIG.4, the right end of the rotor magnetic pole4J is also the tip of the CCW. The rotation angle position θr of the rotor ofFIG.4(b)is 0°, and this θr indicates from −90° to 360°. From −90° to 0° is the same as from 270° to 360°, and is expanded for easy visual visibility. The stator magnetic pole SP and rotor magnetic pole RP shown by the broken line are shown overlapping. Next, the shape of the rotor magnetic pole will be described. The rotor magnetic pole4J ofFIG.4(b)corresponds to the rotor magnetic pole13ofFIG.1, but has a unique rotor shape ofFIG.4. The circumferential angular width θBr of each rotor magnetic pole inFIG.4is 60°. The rotor axial width of each rotor magnetic pole has a different shape between the front 30° width portion and the rear 30° width portion in the CCW direction. The 30° width portion of the front portion has a rotor axial length of Ls/2. The 30° width portion of the rear portion has a rotor axial length of Ls, which is the same length as the rotor axial length of each stator magnetic pole SP. As will be described later, various motor characteristics can be obtained by changing these shapes. InFIG.4(c), the rotor position θr inFIG.4(b)is rotated by 15° from the rotor position θr=0° to CCW, and θr is 15°.FIG.4(d)is further rotated by 15° to CCW, and θr is 30°. Parts of (e), (f), and (g) ofFIG.4are views in which the rotor is similarly advanced to CCW by 15°. By rotating the rotor in this way and changing the rotor rotation angle position θr, the magnetic relative relationship between each stator magnetic pole SP and each rotor magnetic pole RP changes, so each stator magnetic pole SP is excited at an appropriate timing. The rotation torque of the rotor can be obtained. InFIG.4, those operations can be visually confirmed. Next, the relationship between the voltage acting when a current is applied to each winding of the stator magnetic pole, the power of the motor output, and the torque will be described. However, it is a characteristic when the electromagnetic relationship is simply modeled. As described above, the three-dimensional positional relationship of the stator magnetic pole of the reluctance motor ofFIG.4, its winding, the rotor magnetic pole, and the magnetic flux is the configuration of the cross-sectional view of the reluctance motor ofFIG.1. Now, with the A1 phase windings17and18and the A1/ phase windings1C and1D connected in series and a constant current Io [A] with a value close to the continuous rating as the A1 phase current Ia1is energized, the rotor is considered a state in which the coil is rotated to CCW at a constant speed Vso [radian/sec]. The CCW direction ofFIG.1is the right direction of the paper surface ofFIG.4. The winding voltage of the A1 phase at this time is the voltage Va1inFIG.5. The horizontal axis of Va1inFIG.5is time t, and the value of the rotor rotation angle position θr at that time is shown in the lowermost stage ofFIG.5. Although θr shows a value between −30° and 210°, the reluctance torque cycle is 180°, so θr mainly shows a value between 0° and 180°. A front and back part of an angle range 30° are presented for easy viewing. The magnetic flux interlinking with the winding of the A1 phase and the winding voltage Va1of the A1 phase will be described. First, when the rotor magnetic pole4J approaches 0° to 30° of θr, the front portion of the rotor magnetic pole4J faces the A1 phase stator magnetic pole11via an air gap. It is the state from parts (b) to (c) and (d) ofFIG.4. The rotor axial length of the front portion of the rotor magnetic pole4is ½ of the axial length Ls of the stator magnetic pole, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ½ of the maximum value. Here, the voltage inFIG.5is normalized, and the value between 0° and 30° of Va1is shown as 0.5. Next, when the rotor magnetic pole4approaches 30° to 60° of θr, the rear portion of the rotor magnetic pole4faces the stator magnetic pole11of the A1 phase via an air gap. Since the circumferential angular width of the stator magnetic pole11and the circumferential angular width of the front portion of the rotor magnetic pole4J are both 30°, when θr is 30° to 60°, the front portion of the rotor magnetic pole4deviates from the A1 phase stator magnetic pole11. It is the state from parts (d) to (e) and (f) ofFIG.4. The rotor axial length of the rear portion of the rotor magnetic pole4is the same as the axial length Ls of the stator magnetic pole. As a result, the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole becomes ½ of the maximum value by subtracting the front portion and the rear portion. The value between angles 30° and 60° of Va1inFIG.5is shown as 0.5. After all, the A1 phase voltage Va1becomes 0.5 between 0° and 60°. Next, when the rotor magnetic pole4approaches from 60° to 90° of θr, the rear portion of the rotor magnetic pole4deviates from the A1 phase stator magnetic pole11. It is from parts (f) to (g) inFIG.4, and from the position of θr=90°. The rate in changes of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole becomes a negative maximum value during this period. The range between 60° and 90° of Va1inFIG.5is shown as −1.0. When θr becomes 90°, the rear rotor magnetic pole1K begins to face the A1 phase stator magnetic pole11, and the process is repeated from the state where θr is 0°. It is assumed that the magnetic flux passes through the portion where the stator magnetic poles11and12and the rotor magnetic poles4J and1F face each other through the air gap portion. Similarly, the B1 phase windings13and14and the B1/ phase winding are connected in series, and the rotor is rotated to the CCW at a constant speed Vso in a state where a constant current Io is applied as a B1 phase current Ib1. The winding voltage at this time is the voltage Vb1shown inFIG.5. Similarly, the C1 phase windings15and16and the C1/ phase winding are connected in series, and the rotor is rotated to the CCW at a constant speed Vso in a state where a constant current Io is applied as the C1 phase current Ic1. The winding voltage at this time is the voltage Vc1shown inFIG.5. The voltages Va1, Vb1and Vc1have a phase difference of 30° from each other. Next, the relationship between the winding current of each stator magnetic pole, the magnetic flux interlinking the winding, the induced voltage generated in the winding, and the torque generated by the stator magnetic pole is shown by a mathematical formula. However, it is a mathematical formula that holds under various simplified conditions. The soft magnetic material is magnetically saturated at 2.0 Tesla, and in the region of 2.0 Tesla or less, it is linear and has a sufficiently large relative permeability of 2000 or more. The magnetic flux excited by the current is generated only through the narrow air gap between the stator magnetic pole and the rotor magnetic pole, and no peripheral leakage flux is generated. The magnetic resistance of this air gap and the resistance of each winding are ignored. These are the above simplification conditions. The purpose of describing these mathematical formulas is to qualitatively show the relationship between the shape of each part of the reluctance motor of the present invention and voltage, current, torque, and power, and to clarify quantitatively under specific conditions. It also indicates that the voltage and torque are proportional under specific conditions for the convenience of explaining the reluctance motor of the present invention. Next, the magnetic flux φa of the A phase, the B phase, and the C phase in the state where the rotor is rotated to the CCW at a constant speed Vso [radian/sec] while the constant current Io [A] having a value close to the continuous rating is energized, Φb, φc [Wb] and the voltage Va, Vb, Vc [V] and the output power of the reluctance motor Pa, Pb, Pc [W] and the torque Ta, Tb, Tc [Nm] are shown in the following formulas. It is shown by a generalized formula so that it can be applied to the reluctance motors ofFIGS.4,6,10,12, and14shown in the present invention. With respect to the A-phase stator magnetic pole, (rotor axial length)/(axial length Ls of the stator) of each part of the rotor magnetic pole is defined as the axial length ratio Kra. Specifically, (Kra×Ls) is the axial length of the rotor magnetic pole of the portion where the rotor magnetic pole rotates and approaches the A-phase stator magnetic pole. For example, Kra=1 in the portion where the rotor axial length of the rotor magnetic pole is Ls, Kra=0.5 in the portion where the rotor axial length of the rotor magnetic pole is Ls/2, and Kra=0 in the portion where there is no rotor. In a state like the A1 phase stator magnetic pole11and the rotor magnetic pole1J inFIG.1, in the portion where the stator magnetic pole and the rotor magnetic pole face each other, the minute change rate Δφ of the magnetic flux φ passing through and the minute rotation angle Δθr of the rotor are given by the following formula (1). Let the rotor radius be Rr. Δφa=Kr×Ls×Bo×Δθr×Rr(1) dφa/dθr=Kra×Ls×Bo×Rr(2) Bo is the magnetic flux density Bo of the magnetic flux generated in the portion where the stator magnetic pole and the rotor magnetic pole face each other in a state where a constant current Io is applied to the winding of the stator magnetic pole. The constant velocity Vso can be generalized and written as follows. Vso=dθr/dt(3) Since the voltage Va induced in the A-phase winding is connected in series with the windings wound around the two stator magnetic poles, the sum of the winding times of both windings is set to Nwa, and the winding resistance is ignored. It becomes formula (4). Then, it can be transformed into the formula (5). The winding voltage Is a time change rate of the number of magnetic flux chain crossings (Nwa×φa). Va=Nwa×dφa/dt=Nwa×(dφa/dθr)×(dθr/dt)(4)=Kra×Ls×Nwa×Bo×Rr×Vso(5) In the formula (5), since (Ls×Nwa×Bo×Rr×Vso) is assumed to be a constant value, the voltage Va is a value proportional to the axial length ratio Kra. The above-mentioned “normalized voltage inFIG.5” means that (Ls×Nwa×Bo×Rr×Vso), which is a constant value in the formula (5), is assumed to be 1. The power Pa supplied by the A-phase winding is the product of voltage and current, and Is given by the following formula. Pa=Va×Io(6) Then, the torque Ta generated by the A phase is given by the following formula, assuming that the supplied power and the mechanical power are equal. Ta=Pa/Vso(7)=Va×Io/Vso(8) In the formula (8), since Io/Vso is a constant value, the A-phase torque Ta is a value proportional to the A-phase voltage Va. The unit of power is [W], torque is [Nm], voltage is [V], current is [A], speed is [radian/sec], and Ls and Rr are [m]. Since the relationship between formulas (2) and (8) is the same for the B phase and the C phase, the relationship is as following formulas. Vb=Krb×Ls×Nwa×Bo×Rr×Vso(9) Vc=Krc×Ls×Nwa×Bo×Rr×Vso(10) Tb=Vb×Io/Vso(11) Tc=Vc×Io/Vso(12) Here, Krb is the axial length ratio of the B phase, and Krc is the axial length ratio of the C phase. However, these are formulas that hold in the section where the stator magnetic pole and the rotor magnetic pole face each other. The A1 phase voltage Va1, the B1 phase voltage Vb1, and the C1 phase voltage Vc1described with reference toFIG.5correspond to the formulas (5), (9), and (10). Then, based on the formulas (8), (11), and (12), the phase torque values Ta1, Tb1, and Tc1related to the reluctance motor shown inFIG.4are proportional to the respective phase voltages Va1, Vb1, and Vc1, because (Io/Vso) is a constant value. In that sense, the phase torque values Ta1, Tb1, and Tc1are added in parentheses below the phase voltages Va1, Vb1, and Vc1inFIG.5. Next, a method of generating continuous torque in the positive direction of CCW in the reluctance motor ofFIG.4will be described. In the section where Ta1which is the A1 phase torque ofFIG.5generates a positive torque, θr is 0° to 60° and 90° to 150θ and the current shown in Ia1F ofFIG.5is energized. In the section where Tb1which is the B1 phase torque inFIG.5generates a positive torque, θr is 30° to 90° and 120° to 180° and the current Ib1F whose phase is delayed by 30° with respect to Ia1F inFIG.5is energized. In the section where Tc1which is the C1 phase torque inFIG.5generates a positive torque, θr is 60° to 120° and 150° to 210° and the current Ic1F whose phase is delayed by 60° with respect to Ia1F inFIG.5is energized. The CCW voltage and torque in each phase shown inFIG.5have a magnitude of 0.5. However, the torque generation sections each have a phase overlap by 30°, and two of the three phases always generate the torque. As a result, the sum of the torque values in each phase is a constant torque value of 1.0 shown in51of Tt1inFIG.5. Next, a method of generating torque in the CW direction in a state where the reluctance motor ofFIG.4rotates at a speed Vso in the CCW direction will be described with reference toFIG.5. It is also an operation that brakes the motor and regenerates it. In the section where Ta1which is the A1 phase torque ofFIG.5generates a negative torque, θr is 60° to 90° and 150° to 180°, and the current shown in the A1 phase current Ia1R ofFIG.5is energized. In the section where Tb1which is the B1 phase torque inFIG.5generates a negative torque, θr is 90° to 120° and 180° to 210°, and although not shown, the B1 phase current whose phase is delayed by 30° with respect to Ia1R inFIG.5is energized. In the section where Tc1which is the C1 phase torque inFIG.5generates a negative torque, θr is 120° to 150° and 30° to 60°, and although not shown, the C1 phase current whose phase is delayed by 60° with respect to Ia1R inFIG.5is energized. The sum of the torques of each phase is a value shown in52of Tt1inFIG.5, and is a negative constant torque. In this case, there is no portion where the negative torque generation sections of the respective phases overlap, and the torques of the respective phases alternately generate the negative torque to generate a negative constant torque. In addition, Vt1inFIG.5corresponds to the sum of the torques of each phase, and is a virtual voltage obtained by adding the operating voltages of the respective phases. Also, the algorithm that generates torque in the CW direction can basically be generated regardless of the rotation direction and rotation speed, but for convenience of explaining in comparison with CCW torque usingFIG.5, the CW torque at the time of CCW rotation has been described. It was shown that the conventional reluctance motors shown inFIGS.46,47, and48have problems of noise, torque ripple, and average torque decrease. On the other hand, the features of the reluctance motors shown inFIGS.4and5are that the torque generation sections of each phase are widened and the torque generation sections of each phase overlap each other. As shown inFIG.5, since the torque generation ranges of each phase overlap, the effect of simply canceling the torque pulsation of each phase and various countermeasures become easier. For the problem of noise, for example, a method can be considered in which the current of each phase inFIG.5is increased in the first half 30° and the current value is decreased in the latter half 30°. Specifically, the A1 phase current Ia1is made large from 0° to 30° of the rotor rotation angle θr inFIG.5, and is made small from 30° to 60°. Similarly, at this time, the 81 phase current Ib1is increased from 30° to 60° and decreased from 60° to 90°. Then, the C1 phase current Ic1is made large from around 60° to 90° and small from 90° to 120°. In this way, by modifying the current energization method of each phase and reducing the current change rate when the current of each phase is reduced to 0 [A], it is possible to reduce the rate of change of the radial suction force, reduce the vibration of the back yoke, case, etc. of the motor, and reduce the noise. Further, as can be seen from the positive side of the three-phase torque waveforms Ta1, Tb1and Tc1shown inFIG.5, The torque generation range is wide, and the torque waveform is similar to the case where a permanent magnet type three-phase AC synchronous motor is driven by so-called 120° energization. Therefore, deformation and vibration in the circumferential direction of the teeth of the stator and the teeth of the rotor can be reduced, and noise can be reduced. Regarding the problem of torque ripple, as can be inferred from the characteristics ofFIG.48, the torque of the A1 phase torque Ta1ofFIG.5is relatively large from 0° to around 30°, and the torque decreases as it approaches 60°. However, the B1 phase torque Tb1is relatively large between 30° and 60°, and is in a relationship that compensates for the decrease in the A1 phase torque Ta1. In the reluctance motor of the present invention shown inFIGS.4and5, the relationship is the same between the three phases, the torque pulsation of each phase has an effect of canceling each other, and the torque ripple is reduced. It also has the effect of reducing noise and vibration. As described above, in the case of the A phase, the problem of the average torque decrease can be compensated by increasing the current from 0° to the vicinity of 30°, which has a large torque constant. However, in the reluctance motors shown inFIGS.1,4and5, the energization section of the current energizing each phase is doubled, so that the copper loss of the reluctance motor is doubled. The reduction of copper loss can be supplemented by other techniques shown in the present invention, such as shortening the circumferential length of the front portion of each rotor magnetic pole in the CCW direction. Second Embodiment Next, another example of the present invention will be shown and described with reference toFIGS.1,6, and7. The cross-sectional view1of the reluctance motor will be described in common withFIGS.4,6and14. The expression methods ofFIGS.6and7are the same as those ofFIGS.4and5. Here, the description of the expression method and the like will be omitted. The reluctance motor shown inFIG.6has a different rotor shape from the reluctance motor shown inFIG.4. FIG.6(a)shows the shape of the inner peripheral surface of the stator magnetic pole SP as seen from the air gap surface between the stator and the rotor, and the circumferential direction of the CCW is the horizontal axis direction ofFIG.6. It is the figure which developed linearly so that it may be in the right direction of the paper surface inFIG.6. The vertical axis direction of the paper inFIG.6is the direction of the rotor axis.11inFIG.6is an A2 phase stator pole,12is an A2/ phase stator pole,13is a B2 phase stator pole,14is a B2/ phase stator pole,15is a C2 phase stator pole, and16is a C2/ phase stator pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 30° and a rotor axial length of Ls. FIG.6(b)shows the shape of the outer peripheral surface of the rotor magnetic pole RP as seen from the air gap surface, and the circumferential direction of CCW inFIG.1is the horizontal axis direction inFIG.6, that is, the figure which developed linearly so that it may be in the right direction of the paper surface inFIG.6. The value of the rotor rotation angle position θr is shown at the bottom ofFIG.6. The angle position θr inFIG.6Bis 0°. This angle position θr indicates from −90° to 360°. The rotor magnetic pole6J ofFIG.6(b)is the same as the rotor magnetic pole1J ofFIG.1, and the rotor rotation angle position θr is 0°. The circumferential angular width θBr of each rotor magnetic pole inFIG.6is 52.5°. Four rotor magnetic poles of6J,6K,6L, and6M are arranged in a range of 360 degrees. Explaining the shape of each rotor magnetic pole separately for the front portion and the rear portion in the CCW direction, as shown in the figure, the front part in the CCW direction has a circumferential angular width of 15° and a rotor axial length of Ls/2. The rear portion has a circumferential angular width of 37.5° and a rotor axial length of Ls. FIG.6(c)shows a rotor shape rotated by 15° from the rotor position ofFIG.6(b)to CCW, and θr is 15°.FIG.6(d)is further rotated by 15° to CCW, and θr is 30°. Parts (e), (f), and (g) ofFIG.6are views in which the rotor is similarly advanced to CCW by 15°. By rotating the rotor in this way and changing the rotor rotation angle position θr, the magnetic relative relationship between each rotor magnetic pole RP and each stator magnetic pole SP changes. Therefore, it is possible to obtain the rotational torque of the rotor by energizing each phase winding of each stator magnetic pole SP by applying a current at an appropriate timing. Now, with the A2 phase windings17and18and the A2/ phase windings1C and1D connected in series and a constant current Io with a value close to the continuous rating as the A2 phase current Ia2is energized, Consider a state in which the rotor is rotated to CCW at a constant speed Vso. The CCW direction ofFIG.1is the right direction of the paper surface ofFIG.6. The winding voltage at this time is the voltage Va2inFIG.7. The horizontal axis of Va2is time t, and the value of the rotor rotation angle position θr at that time is shown at the bottom ofFIG.7. First, when the rotor magnetic pole6J approaches from 0° to 15° of Br, the front portion of the rotor magnetic pole6J faces the A2 phase stator magnetic pole11via an air gap. Such facing is shown in the states shown by parts (b) to (c) ofFIG.6. The rotor axial length of the front portion of the rotor magnetic pole6J is ½ of the axial length Ls of the stator magnetic pole, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ½ of the maximum value. The value between 0° and 15° of Va2inFIG.7is shown as 0.5. Next, when the rotor magnetic pole6J approaches from 15° to 30° of θr as shown inFIG.6(c), the rear portion of the rotor magnetic pole6J faces the A2 phase stator magnetic pole11via an air gap. The axial length of the rear portion of the rotor magnetic pole6J is Ls, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is the maximum value. The value of Va2inFIG.7between 15° and 30° is shown as 1.0. When the rotor magnetic pole63approaches from 30° to 45° of θr as shown inFIG.6(d), the rear portion of the rotor magnetic pole6J further faces the stator magnetic pole11. On the other hand, the front portion of the rotor magnetic pole6J deviates from the stator magnetic pole11. As a result, the rotational change rate of the magnetic flux passing through the rotor magnetic pole6J and the stator magnetic pole11becomes ½ of the maximum value by subtraction. The value of Va2inFIG.7between 30° and 45° is shown as 0.5. As shown inFIG.6(e), the entire surface of the stator magnetic pole11faces the rotor magnetic pole6J while the rotor magnetic pole63is between 45° and 52.5° of θr. The rotational change rate of the magnetic flux passing through the stator magnetic pole11is 0, and the value of Va2inFIG.7during this period is 0. As shown inFIGS.6(e)to6(f), when the rotor magnetic pole6J is between 52.5° and 60° of θr, the rear portion of the rotor magnetic pole6J deviates from the stator magnetic pole11. The rotational change rate of the magnetic flux passing through the stator magnetic pole11is −1. As shown inFIG.6(f), when the rotor magnetic pole6J is between 75° and 82.5° of θr, the rear portion of the rotor magnetic pole6J deviates from the stator magnetic pole11. The rotational change rate of the magnetic flux passing through the stator magnetic pole11is −1. After all, the value of Va2inFIG.7is −1 between 52.5° and 82.5° of θr. When the rotor rotation angle position θr is from 82.5° to 90°, there is no rotor magnetic pole facing the stator magnetic pole11, and the value of Va2inFIG.7is 0. When θr reaches a rotion angle position 90°, the rotor magnetic pole6K approaches the stator magnetic pole11, and the state shown inFIG.6Bis reached, returning to the initial state of the operation description. The operation is repeated to continuously rotate to the CCW direction. Similarly, the B2 phase windings13and14ofFIG.6and the B2/ phase winding are connected in series, and the rotor is transferred to the CCW at a constant speed Vso with a constant current Io as the B2 phase current Ib2. The winding voltage at this time is the voltage Vb2shown inFIG.7. Similarly, the C2 phase windings15and16and the C2/ phase winding are connected in series, and the rotor is rotated to the CCW at a constant speed Vso in a state where a constant current Io is applied as a C2 phase current Ic2. The winding voltage at this time is the voltage Vc2shown inFIG.7. The voltages Va2, Vb2, and Vc2have a phase difference of 30° from each other. The values of each voltage are normalized by the formulas (5), (9), and (10). The A2 phase voltage Va2, the B2 phase voltage Vb2, and the C2 phase voltage Vc2described with reference toFIG.7. Then, from the formulas (8), (11), and (12), Since (Io/Vso) is a constant value, each phase torque Ta2, Tb2, and Tc2related to the reluctance motor ofFIG.6is respectively proportional to each phase voltage Va2, Vb2, and Vc2. In that sense, the phase torques Ta2, Tb2, and Tc2are added in parentheses below the phase voltages Va2, Vb2, and Vc2inFIG.7. However, it is a mathematical formula that holds under the above-mentioned various simplified conditions. Next, a method of generating continuous torque in the positive direction of CCW with the reluctance motor ofFIG.6will be described. In the section where Ta2, which is the A2 phase torque ofFIG.7, generates a positive torque, θr is 0° to 45° and 90° to 135°, and the current shown in Ia2F ofFIG.7is energized. As described above, since the section between 45° and 52.5° of the rotor rotation angle position θr and between 82.5° and 90° is a section in which A2 phase Va2is 0 [V], It can be used as an increase time and a decrease time of the A2 phase current Ia2F, and can be a trapezoidal current as shown in Ia2F ofFIG.7. Since the copper loss can be reduced by shortening the energization section, the time for increasing or decreasing the current can be shortened according to the rotation speed. In the section where Tb2, which is the B2 phase torque inFIG.7, generates a positive torque, θr is 30° to 75° and 120° to 165°, and the current Ib2F whose phase is delayed by 30° with respect to Ia2F InFIG.7is energized. In the section where Tc2, which is the C2 phase torque inFIG.7, generates a positive torque, θr is 60° to 105° and 150° to 195°, and the current Ic2F whose phase is 60° behind Ia2F inFIG.7is energized. When the positive part of the torque Ta2of the A2 phase, the positive part of the torque Tb2of the B2 phase, and the positive part of the torque Tc2of the C2 phase are added, it becomes 71 of Tt2inFIG.7, and the positive constant torque is 1.0. Therefore, the torque of the three phases has a stepped characteristic of 0.5 and 1.0, respectively, but the rotor shape is such that the torque becomes a constant torque when the torques of the three phases are added. Next, a method of generating torque in the CW direction in a state where the reluctance motor ofFIG.6rotates at a speed Vso in the CCW direction will be described with reference toFIG.7. It is also an operation that brakes the motor and regenerates it. The section in which Ta2, which is the A2 phase torque inFIG.7, generates a negative torque is between 52.5° to 82.5° and 142.5° to 172.5° of θr, and the value of Ta2inFIG.7becomes −1. During this time, the A2-phase current Ia2R shown inFIG.7is energized. The section between 45° and 52.5° of the rotor rotation angle position θr and between 82.5° and 90° is a section in which the A2 phase voltage Va2is 0 [V]. Since it can be used as an increase time and a decrease time of the A2 phase current Ia2R, a trapezoidal current as shown in Ia2R ofFIG.7can be obtained. Similarly, as the B2 phase current Ib2, a current whose phase is delayed by 30° from Ia2R inFIG.7is energized. Also, as the C2 phase current Ic2, a current whose phase is delayed by 6° from Ia2R inFIG.7is energized. The sum of the negative torques of each phase is the value shown in72of Tt2inFIG.7, and is a negative constant torque. In this case, there is no portion where the negative torque generation sections of the respective phases overlap, and the torques of the respective phases alternately generate the negative torque to generate a negative constant torque. The voltage Vt2inFIG.7corresponds to the sum of the torques of each phase, and is also a virtual voltage obtained by adding the operating voltages of the respective phases. Further, the algorithm for generating the torque in the CW direction can be generated in principle regardless of the rotation direction and the rotation speed, but for convenience of explaining in comparison with CCW torque usingFIG.7, the CW torque generated during the CCW rotation has been described. The motor of the present invention shown inFIGS.1,6and7has unique characteristics as described above. For the problem of noise, for example, a method of increasing the current of each phase inFIG.7in the first half and decreasing the current value in the second half can be considered. Specifically, for example, the A2 phase current Ia2is made large from 0° to 15° of the rotor rotation angle θr inFIG.7, and is made small from 30° to 45°. Similarly, at this time, the B2 phase current Ib2is Increased from 30° to 45° and decreased from 60° to 75°. Similarly, the C2 phase current Ic2is increased from 60° to 75° and decreased from 90° to 105°. In this way, by modifying the current energization method of each phase, that is, the magnitude of the current, and reducing the current change rate when the current of each phase decreases from a large current value to 0 [A], The rate of change of the radial direction suction force will be reduced. As a result, vibration of the back yoke and case of the motor can be reduced, and noise can be reduced. Further, since the current waveforms Ia2F and Ia2R inFIG.7can be trapezoidal current waveforms, noise can be reduced by suppressing the current change rate such as a rapid Increase or decrease of each phase current. Further, as shown inFIG.7, the torque of each phase generates torque in a section of 50%. Then, in the section where the torque of each phase is 0.5 inFIG.7, two of the three phases generate torque. In this way, by generating torque in a section where the stator magnetic poles of each phase are wide and by overlapping the torque generating sections with each other in the three phases, smoother rotation can be realized and noise can be reduced. For comparison, the torque of one phase of the three-phase sinusoidal AC motor is shown by the broken line inFIG.7. This broken line is a squared formula of a sine wave, and its conversion formula is (SIN θ×SIN θ)=(1−COS(2θ))/2. Note that this formula and the broken line are ideal torque waveform shapes of one phase of the three-phase AC motor, and when the torques of the three phases are added, the constant value becomes 3/2. Here, focusing only on the positive torque portion of Ta2inFIG.7, smoothing the stepped torque waveform and considering the fundamental wave component, it can be inferred that the waveform is similar to the broken line. Therefore, the positive torque of each phase inFIG.7is similar to the torque of a synchronous motor driven by a three-phase sine wave, even though it is a reluctance motor driven by a current having a substantially square wave shape, and it can be expected to reduce noise and vibration. Further, as described above, the total of the positive torques of the reluctance motor ofFIG.6is a constant value shown in71of Tt2ofFIG.7. The copper loss in the driving method ofFIG.7will be described. When rotating in the CCW direction, the current of each phase energizes the current at 50% of the total energization section, and the copper loss Increases as compared with the case of 33% of the energization section of the conventional method ofFIG.47. Priority is given to the quietness of the motor. A method for significantly reducing copper loss and a method for increasing torque of the motor of the present invention will be described later. Further, the shape of each rotor magnetic pole shown inFIG.6has a two-stage shape of a front portion having an axial length of Ls/2 and a rear portion having an axial length of Ls, but it can be deformed into various shapes. For example, it is possible to modify the shape of the rotor magnetic pole so that the positive side portion of the A2 phase torque Ta2shown inFIG.7has a characteristic closer to (1−COS (2θ))/2. The staircase shape becomes smoother. Further, since each torque characteristic can be created by the relative magnetic characteristics of the stator magnetic pole and the rotor magnetic pole, not only the rotor magnetic pole shape but also the stator magnetic pole shape can be deformed. Further, inFIG.6, the length of the front portion of each rotor magnetic pole in the rotor axial direction Is Ls/2, which is doubled in terms of the magnetic resistance value in the radial direction, that is, 200%. Although The length in the rotor axial direction of the front portion, that is, the magnetic resistance value in the radial direction can take various values, if it is 20% or more larger than the magnetic resistance value at the rear portion of the rotor magnetic pole, the effect of expanding the angle width for outputting torque and reducing noise can be exhibited. At this time, each stator magnetic pole can generate torque over an angular width larger than the circumferential angular width of the stator magnetic pole. Further, as a method of changing the torque waveform from the stepped shape ofFIG.7to a smoother shape, there is a method of changing the drive current waveform from a rectangular shape to a trapezoidal wave or a smoother waveform, and it can be selected according to the shape of the front portion of the rotor magnetic pole. The length of the front portion of the rotor magnetic pole in the rotor axial direction, that is, the method of designing and manufacturing the magnetic resistance value in the radial direction, is a promising method such as drilling a hole in an electromagnetic steel sheet shown later inFIG.17, and it is excellent in terms of magnetic characteristics such as eddy currents, productivity, and mass productivity. Further, as shown inFIGS.4,6,10,12, and16, various values and various shapes can be selected for the circumferential angular width of the front portion of the rotor magnetic pole. The torque generation width of each rotor magnetic pole is expanded, noise is reduced, copper loss is increased, and the advantages and disadvantages of the drive circuit are involved. Further, as shown inFIGS.7,11and13, since the torque shape can be stepped if the circumferential angular width of the front portion of the rotor magnetic pole is 10% or more of the circumferential angular width of the rear portion, the effect of expanding the torque generation range and reducing noise can be expected. Further, in the motor of the present invention shown inFIGS.1,6and7, the example in which the torque of each phase does not overlap with respect to the torque of CW has been described, but the width of each stator magnetic pole in the circumferential direction is changed from 30°. If (30°+α), the CW torque can be overlapped by the angle of α. And the driving method for the angle of a can also be changed. It is also possible to change the shape of the stator magnetic poles before and after the circumferential direction like the rotor magnetic poles. However, there is a problem of space for winding arrangement. It is also possible to skew the rotor or the stator. Third Embodiment Next,FIG.8(a)shows an example of a cross-sectional view of another reluctance motor of the present invention. It is a reluctance motor with 8 stator magnetic poles and 6 rotor magnetic poles. The expression method ofFIG.8Ais the same as that ofFIG.1. The configuration of the reluctance motor shown inFIG.8Ais point-symmetrical with respect to the center point of the rotor, and the generated magnetic flux passes 180° opposite to the electric angle. In that case, when the number of stator magnetic poles is a multiple of 4, there will be a portion where the north and south poles of the stator magnetic poles cannot be arranged alternately in the circumferential direction.FIG.8shows an example in which the arrangement of the stator magnetic poles is partially irregular. On the other hand, when the number of stator magnetic poles is6,10,14, or18inFIG.9, the north and south poles of the stator magnetic poles can be alternately arranged in the circumferential direction. A reference sign101ofFIG.8is an A3 phase stator magnetic pole, in which a concentrated winding81shown by a broken line is wound, the winding is indicated by a current symbol, and a one-way A3 phase current Ia3is energized in the direction of the current symbol. Reference sign102denotes an A3/ phase stator magnetic pole, which winds the concentrated winding81shown by the broken line and energizes the unidirectional A3 phase current Ia3In the direction of the current symbol. Normally, the winding81and the winding82are connected in series, and the same A3 phase current Ia3Is applied to both windings. At that time,102becomes the north pole and101becomes the south pole. In the case of the state (a) ofFIG.8, the magnetic flux excited passes through the rotor magnetic poles10M and10J from the stator magnetic pole102, passes through the stator magnetic pole101, and makes a round through the back yoke. In that case, CCW torque is generated in the rotor. Similarly, a reference sign103denotes a B3 phase stator magnetic pole, which winds the concentrated winding83shown by the broken line. Reference sign104denotes a B3/ phase stator magnetic pole, which winds the concentrated winding84shown by the broken line. The winding83and the winding84are connected in series, and the same B3 phase current Ib3is applied to both windings in the direction of the current symbol. At that time,103becomes the north pole and104becomes the south pole. Similarly, reference sign105denotes a C3 phase stator magnetic pole, which winds the concentrated winding85indicated by the broken line. Reference sign106denotes a C3/ phase stator magnetic pole, which winds the concentrated winding86shown by the broken line. The winding85and the winding86are connected in series, and the same C3 current Ic3is applied to both windings in the direction of the current symbol. At that time,106becomes the north pole and105becomes the south pole. Similarly, a reference sign107denotes a D3 phase stator magnetic pole, which winds the concentrated winding87shown by the broken line. Reference sign108denotes a D3/ phase stator magnetic pole, which winds the concentrated winding88shown by the broken line. The winding87and the winding88are connected in series, and the same D3 current Id3is applied to both windings in the direction of the current symbol. At that time,107becomes the north pole and108becomes the south pole. Here, the same poles of the S poles of the stator magnetic poles101and108are aligned in the circumferential direction, and the positive current side of the winding81and the negative current side of the winding88are arranged in the slots located between them. Similarly, the same poles of the north poles of the stator magnetic poles107and102are arranged in the circumferential direction, and the positive current side of the winding87and the negative current side of the winding82are arranged in the slots located between them. As described above, when the number of stator magnetic poles is an integral multiple of 4, such Irregularity occurs. Next, the voltage, current, and torque of the reluctance motor ofFIG.8Awill be shown and described inFIGS.10and11. This shows a situation where the rotation in the CCW direction generates CCW torque or CW torque. InFIG.10A, the shape of the inner peripheral surface of the stator magnetic pole SP seen from the air gap surface between the stator and the rotor is linearly developed so that the circumferential direction of the CCW is the horizontal axis direction ofFIG.10. The vertical axis direction inFIG.10is the rotor axial direction. InFIG.10,101is an A3 phase stator pole,102is an A3/ phase stator pole,103is a B3 phase stator pole,104is a B3/ phase stator pole,105is a C3 phase stator pole, and106is a C3/ phase stator pole.107is a D3 phase stator magnetic pole, and108is a D3/ phase stator magnetic pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 22.5° and a rotor axial length of Ls. Those having the same reference signs inFIG.8(a)andFIG.10are the same. FIG.10(b)shows the outer peripheral surface shape of the rotor magnetic pole RP as seen from the air gap surface, and the circumferential direction of the CCW ofFIG.8(a)is the horizontal axis direction ofFIG.10. That is, it is a figure developed in a straight line so as to be in the right direction of the paper surface ofFIG.10. InFIG.8(a), the starting point of the rotor is the rotation angle position of the clockwise end of the A3 phase stator magnetic pole101, and the rotor rotation angle position θr is from the starting point to the end of the rotor magnetic pole10J in the CCW direction. The starting point of the rotor inFIG.10is the left end of the stator magnetic pole101on the paper. The value of the rotor rotation angle position θr at the bottom of that point is set to 0°. The rotor rotation angle position θr inFIG.10is from the start point to the right end of the rotor magnetic pole10J. InFIG.10, the right end of the rotor magnetic pole10J is also the tip of the CCW of10J inFIG.8(a). The rotation angle position θr of the rotor ofFIG.10(b)is 0°. InFIG.10, the rotation angle position θr is shown from −90° to 360°. Next, the shape of the rotor magnetic pole will be described. The circumferential angular width θBr of each rotor magnetic pole inFIGS.8(a)and10is 33.75°. The width of each rotor magnetic pole in the rotor axis direction is different between the 7.5° width portion in the front portion and the 26.25° width portion in the rear portion in the CCW direction. The 7.5° width portion of the front portion has a rotor axial length of Ls/2. The 26.25° portion of the rear portion has a rotor axial length of Ls, which is the same length as the rotor axial length of each stator magnetic pole SP. InFIG.10(c), the rotor position θr inFIG.10(b)is rotated by 7.5° from the rotor position θr=0° in the CCW direction, and θr is 7.5°.FIG.10(d)is further rotated by 15° to CCW, and θr is 22.5°. InFIG.10, θr in (e) is 30°, θr in (f) is 33.75°, and θr in (g) is 56.25°. By rotating the rotor in this way and changing the rotor rotation angle position θr, the magnetic relative relationship between each stator pole SP and each rotor pole RP changes. Therefore, rotational torque of the rotor can be obtained by exciting each stator magnetic pole SP at an appropriate timing. Next, the relationship between the voltage acting when a current is applied to each winding of the stator magnetic pole, the motor output power, and the torque will be described. However, it is a characteristic when the electromagnetic relationship is simply modeled. Now, consider the A3 phase winding81and the A3/ phase winding82ofFIG.8Aare connected in series, and a constant current Io [A] having a value close to the continuous rating as the A3 phase current Ia3is energized, and the rotor is rotated to CCW at a constant speed Vso [radian/sec]. The CCW direction ofFIG.8Ais the right direction of the paper surface ofFIG.10. The winding voltage of the A3 phase at this time is the voltage Va3inFIG.11. The horizontal axis of Va3inFIG.11is the time t, and the value of the rotor rotation angle position θr at that time is shown in the lowermost stage ofFIG.11. First, the magnetic flux interlinking with the A3 phase winding when the rotor rotation angle position θr approaches from 0° to 7.5° and the A3 phase winding voltage Va3will be described. The rotor magnetic pole10J starts to face the A3 phase stator magnetic pole101from 0° of θr via an air gap. It is the state from (b) to (c) ofFIG.10. The rotor axial length of the front portion of the rotor magnetic pole10J is ½ of the axial length Ls of the stator magnetic pole, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ½ of the maximum value. Here, the voltage inFIG.11is normalized by the formulas (5), (9), (10), and The A3 phase winding voltage Va3between 0° and 7.5° of Va3is shown as 0.5. Next, when θr is between 7.5° and 22.5°, it is the state from a part (c) to a part (d) inFIG.10. The rear portion of the rotor magnetic pole10J faces the A3 phase stator magnetic pole101, and the magnetic flux passing through the rotor magnetic pole10J has a maximum axial length Ls and increases with rotation. The rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole becomes the maximum value. As a result, the winding voltage Va3of the A3 phase in which θr inFIG.11is between 7.5° and 22.5° is 1.0. Next, when θr is between 22.5° and 30°, it is the state from (d) to (e) inFIG.10. The rear portion of the rotor magnetic pole10J faces the A3 phase stator magnetic pole101, and the passing magnetic flux increases with rotation. On the other hand, the front portion of the rotor magnetic pole10J deviates from the A3 phase stator magnetic pole101. An increase in the subtraction of the magnetic fluxes is ½, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ½ of the maximum value. As a result, the winding voltage Va3of the A3 phase in which θr inFIG.11is between 22.5° and 30° is 0.5. Next, when θr is between 30° and 33.75°, it is the state from a part (e) to a part (f) inFIG.10. During this period, since the rotor magnetic pole103faces the entire surface of the stator magnetic pole101, the magnetic flux passing through is constant. Therefore, the rotational change rate of the magnetic flux passing from the rotor magnetic pole to the stator magnetic pole is 0. The winding voltage Va3of the A3 phase in which θr inFIG.11is between 30° and 33.75° is 0. Next, when θr is between 33.75° and 56.25°, it is the state from a part (f) to a part (g) inFIG.10. The rear portion of the rotor magnetic pole10J deviates from the state of facing the A3 phase stator magnetic pole101, and is completely disengaged when θr is 56.25°. During this time, the magnetic flux passing through decreases with rotation. The rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole has a negative maximum value. As a result, the winding voltage Va3of the A3 phase in which θr inFIG.11is between 33.75° and 56.25° is −1.0. Next, when θr is between 56.25° and 60°, it is a state from a part (g) inFIG.10to a part (b) inFIG.10in the original state. Since the distance between the rotor magnetic poles is 60°, the process returns to the original state (b) where the explanation was first started. During this period, the stator magnetic pole101does not face the rotor magnetic pole10J, so the magnetic fluxes passing through is 0 and constant. The winding voltage Va3of the A3 phase in which θr inFIG.11is between 56.25° and 60° is 0. As described above, θr rotates by repeating the operation of 0° to 60°. As for the B3 phase, the winding83wound around the B3 phase stator magnetic pole103inFIG.8(a)and the winding84wound around the B3/ phase stator magnetic pole are wound in series with the same polarity. Then, the rotor is rotated to CCW at a constant speed Vso [radian/sec] while a constant current Io [A] having a value close to the continuous rating is applied to this winding. The winding voltage of the B3 phase at this time is the voltage Vb3ofFIG.11, which is a voltage whose phase is delayed by 45° with respect to the A3 phase voltage Va3. Since the period is 60°, it is also a voltage whose phase is advanced by 15°. Similarly, the C3 phase voltage Vc3is the voltage of the winding in which the windings85and86are wound in series, which is the voltage Vc3inFIG.11, which is a voltage whose phase is delayed by 30° with respect to the A3 phase voltage Va3. Similarly, the D3 phase voltage Vd3is the voltage of the winding in which the windings87and88are wound in series, which is the voltage Vd3inFIG.11, which Is a voltage whose phase is delayed by 15° with respect to the A3 phase voltage Va3. The voltage of each of these phases has a relationship provided by the formulas (1) to (12). The same formulae apply to the D phase. However, it is a mathematical formula that holds under the above-mentioned various simplified conditions. Further, the values of each voltage, each current, and each torque are normalized by the formulas (5), (9), (10) and the like. The A3 phase voltage Va3, the B3 phase voltage Vb3, the C3 phase voltage Vc3, and the D3 phase voltage Vd3described with reference toFIG.11have the relationship of the formula (5). Then, (Io/Vso) is a constant value in A3 phase torque Ta3, B3 phase torque Tb3, C3 phase torque Tc3, D3 phase torque Td3which related to the reluctance motor ofFIG.8(a)so that the A phase torque is proportional to the A phase voltage in the formula (8). It is proportional to each phase voltage Va3, Vb3, Vc3, and Vd3, respectively. In that sense, the phase torques Ta3, Tb3, Tc3, and Td3are added in parentheses under each phase voltage Va3, Vb3, Vc3, and Vd3inFIG.11. Next, a method of generating continuous torque in the positive direction of CCW by the reluctance motor shown inFIG.8A,FIG.10andFIG.11will be described. In the section where Ta3, which is the A3 phase torque ofFIG.11, generates a positive torque, θr is 0° to 30°, 60° to 90°, and the like, and the current shown in Ia3F ofFIG.11is energized. Here, for example, since the winding voltage Va3is 0 between θr of −3.75° and 0° and between 30° and 33.75°, there is no effect on torque, and it is used as the current increase time and decrease time. doing. In the section where Tb3, which is the B3 phase torque inFIG.11, generates a positive torque, θr is 45° to 75°, 105° to 135°, and the like, and the current Ib3F whose phase is delayed by 45° with respect to Ia3F inFIG.11is energized. In the section where Tc3, which is the C3 phase torque inFIG.11, generates a positive torque, θr is 30° to 60°, 90° to 120°, and the like, and the current Ic3F whose phase is delayed by 30° with respect to Ia3F inFIG.11is energized. In the section where Td3, which is the D3 phase torque inFIG.11, generates a positive torque, θr is 15° to 45° and 75° to 105°, and the current Id3F whose phase is delayed by 15° with respect to Ia3F inFIG.11is energized. The sum of the positive torques of each phase at this time is the torque shown in111of Vt3inFIG.11, which is a constant value having a magnitude of 1.5. At all times, two of the four phases are generating torque, and the sum is 1.5. Next, a method of generating torque in the CW direction in a state of rotating at a speed Vso in the CCW direction with the reluctance motors ofFIGS.8A,10and11will be described with reference toFIG.11. It is also an operation that brakes the motor and regenerates it. In the section where Ta3, which is the A3 phase torque inFIG.11, generates a negative torque, θr is 33.75° to 56.25°, 93.75° to 116.25°, and the like, the trapezoidal current shown by the solid line of Ia3R inFIG.11is energized. Here, for example, since the winding voltage Va3is 0 between θr of −3.75° and 0° and between 30° and 33.75°, there is no effect on torque, and it is used as the current increase time and decrease time. The same applies to other current cycles of Ia3R. In the section where Tb3, which Is the B3 phase torque inFIG.11, generates a negative torque, θr is 18.75° to 41.25°, 78.75° to 101.25°, and the like, and the current Ib3R whose phase is 45° behind Ia3R inFIG.11is energized. In the section where Tc3, which is the C3 phase torque inFIG.11, generates a negative torque, θr is 48.75° to 71.25°, 108.75° to 131.25°, and the like, the current Ic3R whose phase is delayed by 30° with respect to Ia3R inFIG.11is energized. In the section where Td3, which is the D3 phase torque inFIG.11, generates a negative torque, θr is 48.75° to 71.25°, 108.75° to 131.25°, and the like, and the current Id3R whose phase Is delayed by 15° with respect to Ia3R inFIG.11is energized. The sum of the torques of each phase is the value shown in112of Tt3inFIG.11, and has a torque characteristic in which the values of −1.0 and −2.0 are repeated every 7.5°. The average torque is −1.5, which is the same magnitude as the positive torque. However, this characteristic has a large torque pulsation, which is not preferable from the viewpoint of noise and vibration. As one of the countermeasures, there is a method in which the current energization method is a trapezoidal current waveform shown by a broken line in1a3R ofFIG.11. By making the current waveform of each phase into this trapezoidal waveform, the negative torque of the reluctance motor ofFIG.10has a torque characteristic of a constant value of magnitude −1.0. As a result, the torque pulsation becomes zero. Further, in terms of current control, it is possible to create an increase time and a decrease time of the current, so that the difficulty in current control can be solved. Note that Vt3inFIG.11corresponds to the sum of the torques of each phase, and is a virtual voltage obtained by adding the operating voltages of the respective phases. Further, although the algorithm for generating the torque in the CW direction can be basically generated regardless of the rotation speed, the CW torque at the time of CCW rotation was described for the convenience of explaining in comparison with the CCW torque usingFIG.11. The reluctance motor of the present invention shown inFIGS.8(a),10and11has unique characteristics as described above. To solve the problem of noise, for example, a method of increasing each phase current such as the A3 phase current Ia3F inFIG.11in the first half of each cycle and decreasing the current value in the latter half can be considered. Since the torque of each phase overlaps with the torque of the other phase, the two phases complement each other in the first half and the second half. Specifically, for example, the A3 phase current Ia3is made large from 0° to 15° of the rotor rotation angle θr inFIG.11, and is made small from 15° to 30°. Similarly, at this time, the D3 phase current Id3is increased from 15° to 30° and decreased from 30° to 45°. Similarly, the C3 phase current Ic3is increased from 30° to 45° and decreased from 45° to 60°. Similarly, the B3 phase current Ib3is increased from 45° to 60° and decreased from 60° to 75°. In this way, by modifying the current energization method of each phase, that is, the magnitude of the current, and reducing the current change rate when the current of each phase decreases from a large current value to 0 [A], it is possible to reduce the rate of change of the radial suction force, reduce the vibration of the back yoke, case, etc. of the motor, and reduce the noise. Further, since the current waveforms Ia3F and Ia3R inFIG.11can be trapezoidal current waveforms, noise can be reduced by suppressing the current change rate such as a rapid increase or decrease of each phase current. Further, as shown inFIG.11, the torque of each phase generates torque in a section of 50%. As for the torque of each phase, two phases always generate torque. In this way, by generating torque in a section where the stator magnetic poles of each phase are wide and by overlapping the torque generating sections with each other in the three phases, smoother rotation can be realized and noise can be reduced. Further, when focusing only on the positive torque portion of Ta3inFIG.11and smoothing the stepped torque waveform to estimate the fundamental wave component, the shape is close to a sine wave squared formula (1−COS(2θ))/2. Therefore, since the positive torque of each phase inFIG.11is close to the torque of a synchronous motor driven by a 4-phase sine wave, even though it is a reluctance motor driven by a current having a substantially square wave shape, it can be expected to reduce noise and vibration. Further, as described above, the total positive torque of the reluctance motor ofFIG.10is also a constant value shown in111of Tt3ofFIG.11. The copper loss in the driving method ofFIG.11will be described. When rotating to CCW, the current of each phase energizes the current at 50% of the pre-energized section, and the copper loss increases as compared with the case of 33% of the energized section of the conventional method ofFIG.47. Priority is given to the quietness of the motor. The method for reducing the copper loss of the motor of the present invention will be described with reference toFIGS.8(b)and42. The drive circuit becomes a little complicated. In addition, some inconveniences occur in the method of utilizing the permanent magnet shown inFIG.26. The order in which the N and S polarities of the stator magnetic poles shown inFIG.8(a)are arranged in the circumferential direction can be changed, although there are various advantages and disadvantages. Further, the shape of each rotor magnetic pole shown inFIG.10can be deformed into various shapes. For example, the staircase shape can be made smoother. Further, since each torque characteristic can be created by the relative magnetic characteristics of the stator magnetic pole and the rotor magnetic pole, not only the rotor magnetic pole shape but also the stator magnetic pole shape can be deformed. It is also possible to skew the rotor or stator. Fourth Embodiment Next,FIG.9(a)shows an example of a cross-sectional view of another reluctance motor of the present invention. It is a reluctance motor with 10 stator magnetic poles and 6 rotor magnetic poles. The expression method ofFIG.9(a)is the same as that ofFIG.1and other figures. Since the number of stator magnetic poles is 10, it is possible to alternately arrange the north pole and the south pole of the stator magnetic poles in the circumferential direction, and an example thereof is shown. The north and south magnetic poles are arranged symmetrically with respect to the center point of the rotor. The generated magnetic flux is configured to pass from the stator pole of the N pole through the rotor magnetic pole, to the stator pole of the S pole opposite by 180° in electrical angle, and to make a round through the back yoke. A Reference sign121denotes an A4 phase stator magnetic pole, which winds a concentrated winding91indicated by a broken line, indicates the winding with a current symbol, and energizes a one-way A4 phase current Ia4in the direction of the current symbol. A reference sign122denotes an A3/ phase stator magnetic pole, which winds the concentrated winding91shown by the broken line and energizes the unidirectional A3 phase current Ia3in the direction of the current symbol. Normally, the winding91and the winding92are connected in series, and the same A4 phase current Ia4is applied to both windings. At that time, a reference sign122becomes the north pole and the A3/ phase stator magnetic pole121becomes the south pole. In the case of the state shown in a part (a) ofFIG.9, the magnetic fluxes to be excited passes through the rotor magnetic poles12M and12J from the stator magnetic pole122, passes through the stator magnetic pole121, and makes a round through the back yoke. In that case, the CCW torque is generated in the rotor. Similarly, a reference sign123shows a B4 phase stator magnetic pole and winds the concentrated winding93shown by the broken line. A reference sign124denotes a B4/ phase stator magnetic pole, which winds the concentrated winding94shown by the broken line. Windings93and94are connected in series, and the same B4 phase current Ib4is applied to both windings. At that time, the magnetic pole124becomes the north pole and the magnetic pole123becomes the south pole. Similarly, a reference sign125denotes a C4 phase stator magnetic pole, which winds the concentrated winding95shown by the broken line. A reference sign126denotes a C4/ phase stator magnetic pole, which winds the concentrated winding96shown by the broken line. The windings95and96are connected in series, and the same C4 phase current Ic4is applied to both windings. At that time, the magnetic pole126becomes the north pole and the magnetic125becomes the south pole. Similarly, a reference sign127is a D4 phase stator magnetic pole, and winds the concentrated winding97shown by the broken line. A reference sign128denotes a D4/ phase stator magnetic pole, which winds the concentrated winding98shown by the broken line. The windings97and98are connected in series, and the same D4 phase current Id4is applied to both windings. At that time, the magnetic pole128becomes the north pole and the magnetic pole127becomes the south pole. Similarly, a reference sign129shows an E4 phase stator magnetic pole, and winds the concentrated winding99shown by the broken line. A reference sign12A is an E4/ phase stator magnetic pole, which winds the concentrated winding9A indicated by the broken line. The windings99and9A are connected in series, and the same E4 phase current Ie4is applied to both windings. At that time, the magnetic pole12A becomes the north pole and the magnetic pole129becomes the south pole. Next, the voltage, current, and torque of the reluctance motor ofFIG.9(a)will be shown and described inFIGS.12and13. This shows that the rotation in the CCW direction generates CCW torque or CW torque.FIG.9Ashows a linear development of the shape of the inner peripheral surface of the stator magnetic pole SP seen from the air gap surface between the stator and the rotor so that the circumferential direction of the CCW is the horizontal axis direction ofFIG.12. The vertical axis direction inFIG.12is the rotor axis direction. InFIG.12, a reference sign121shows an A4 phase stator pole, a reference sign122shows an A4/ phase stator pole, a reference sign123shows a B4 phase stator pole, a reference sign124shows a B4/ phase stator pole, a reference sign125shows a C4 phase stator pole, a reference sign126shows a C4/ phase stator pole, a reference sign127shows a D4 phase stator pole, a reference sign128shows a D4/ phase stator pole, a reference sign129shows an E4 phase stator pole, and a reference sign12A shows an E4/ phase stator pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 18° and a rotor axial length of Ls. Those having the same reference signs inFIG.9(a)andFIG.12have the same reference signs. FIG.12(b)is a linear development of the outer peripheral surface shape of the rotor magnetic pole RP seen from the air gap surface so that the circumferential direction of the CCW ofFIG.9(a)is the horizontal axis direction ofFIG.12. That is, it is a figure developed linearly so as to be in the right direction of the paper surface ofFIG.12. InFIG.9(a), the start point of the rotor is the rotation angle position of the clockwise end of the A4 phase stator magnetic pole121, and the rotor rotation angle position θr is from the start point to the CCW direction end of the rotor magnetic pole12J. The starting point of the rotor inFIG.12is the left end of the stator magnetic pole121on the paper. The value of the rotor rotation angle position θr at the bottom of that point is set to 0°. The rotor rotation angle position θr inFIG.12is from the start point to the right end of the rotor magnetic pole12J. InFIG.12, the right end of the rotor magnetic pole12J is also the tip of the CCW of12J inFIG.9(a). The rotation angle position θr of the rotor ofFIG.12(b)is 0°, and this θr indicates from −72° to 360°. Next, the shape of the rotor magnetic pole will be described. The circumferential angular width Br of each rotor magnetic pole inFIG.12is 33°. The rotor axial width of each rotor magnetic pole has a different shape between a 6° width portion in the front portion and a 27° width portion in the rear portion in the CCW direction. The 6° width portion of the front portion has a rotor axial length of Ls/2. The 27° portion of the rear portion has a rotor axial length of Ls, which is the same length as the rotor axial length of each stator magnetic pole SP. The axial length of the front portion Is halved of that of the rear portion. InFIG.12(c), the rotor position θr inFIG.12(b)is rotated by 6° from the rotor position θr=0° to CCW, and θr is 6°.FIG.12(d)is further rotated by 12° to CCW, and θr is 18°. InFIG.12, θr in (e) is 24°, θr in (f) is 33°, θr in (g) is 51°, and θr in (h) is 60°. By rotating the rotor in this way and changing the rotor rotation angle position θr, the magnetic relative relationship between each stator pole SP and each rotor pole RP changes, and rotational torque of the rotor can be obtained by exciting each stator magnetic pole SP at an appropriate timing. Next, the relationship between the voltage acting when a current is applied to each winding of the stator magnetic pole, the motor output power, and the torque will be described. However, it is a characteristic when the electromagnetic relationship is simply modeled. Now, consider the A4 phase winding91and the A3/ phase winding92ofFIG.9Aare connected in series, and a constant current Io [A] having a value close to the continuous rating as the A4 phase current Ia4is energized, and the rotor is rotated to CCW at a constant speed Vso [radian/sec]. The CCW direction ofFIG.9Ais the right direction of the paper surface ofFIG.12. The winding voltage of the A4 phase at this time is the voltage Va4inFIG.13. The horizontal axis of Va4inFIG.13is the time t, and the value of the rotor rotation angle position θr at that time is shown in the lowermost stage ofFIG.13. First, the magnetic flux interlinking with the A4 phase winding when the rotor rotation angle position θr approaches from 0° to 6° and the A4 phase winding voltage Va4will be described. The rotor magnetic pole123starts to face the A4 phase stator magnetic pole121from 0° of θr via an air gap. It is the state from the part (b) to the part (c) ofFIG.12. The rotor axial length of the front portion of the rotor magnetic pole12J is ½ of the axial length Ls of the stator magnetic pole, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ½ of the maximum value. Here, the voltage inFIG.13is normalized, and the A4 phase winding voltage Va4between 0° and 6° of Va4is shown as 0.5. Next, when θr is between 6° and 18°, it is the state from the part (c) to the part (d) inFIG.12. The rear portion of the rotor magnetic pole12J faces the A4 phase stator magnetic pole121, and the magnetic flux passing through the rotor magnetic pole12J has a maximum axial length Ls and increases with the rotation. And the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole becomes the maximum value. As a result, the A4 phase winding voltage Va4in which θr inFIG.13is between 6° and 18° is 1.0. Next, when θr is between 18° and 24°, it is the state from the part (d) to the part (e) inFIG.12. The rear portion of the rotor magnetic pole12J faces the A4 phase stator magnetic pole121, and the passing magnetic flux increases with rotation, while the front portion of the rotor magnetic pole12J deviates from the A4 phase stator magnetic pole121. The Increase in the subtraction of the magnetic flux is ½, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ½ of the maximum value. As a result, the A4 phase winding voltage Va4in which θr inFIG.13is between 18° and 24° is 0.5. Next, when θr is between 24° and 33°, it is the state from the part (e) to the part (f) inFIG.12. During this period, since the rotor magnetic pole12J faces the entire surface of the stator magnetic pole121, the magnetic flux passing through is constant. Therefore, the rotational change rate of the magnetic flux passing from the rotor magnetic pole to the stator magnetic pole is 0. The winding voltage Va4of the A4 phase in which θr inFIG.13is between 24° and 33° is 0. Next, when θr is between 33° and 51°, it is the state from the part (f) to the part (g) inFIG.12. The rear portion of the rotor magnetic pole12J deviates from the state of facing the A4 phase stator magnetic pole121, and completely deviates when θr is 51°. During this time, the magnetic flux passing through decreases with rotation. The rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole has a negative maximum value. As a result, the winding voltage Va4of the A4 phase in which θr inFIG.13is between 33° and 51° becomes −1.0. Next, when θr is between 51° and 60°, it is the state from the part (g) inFIG.12to the part (b) inFIG.12in the original state. Since the distance between the rotor magnetic poles is 60°, the process returns to the original state (b) where the explanation was first started. During this period, the stator magnetic pole121does not face the rotor magnetic pole12J, so the magnetic flux passing through is 0 and constant. The winding voltage Va4of the A4 phase in which θr inFIG.13is between 51° and 60° is 0. As described above, θr rotates by repeating the operation of 0° to 60°. As for the B4 phase, the winding93wound around the B4 phase stator magnetic pole123inFIG.9(a)and the winding94wound around the B4/ phase stator magnetic pole are wound in series with the same polarity. Then, the rotor is rotated in the CCW direction at a constant speed Vso [radian/sec] while a constant current Io [A] having a value close to the continuous rating is applied to this winding. The winding voltage of the B4 phase at this time is the voltage Vb4shown inFIG.13, which is a voltage whose phase is delayed by 12° with respect to the A4 phase voltage Va4. Similarly, the C4 phase voltage Vc4is the voltage of the winding in which the windings95and96are wound in series, which is the voltage Vc4inFIG.13, which is a voltage whose phase is delayed by 24° with respect to the A4 phase voltage Va4. Similarly, the D4 phase voltage Vd4is the voltage of the winding in which the windings97and98are wound in series, which is the voltage Vd4inFIG.13, which is a voltage whose phase is delayed by 36° with respect to the A4 phase voltage Va4. Similarly, the E4 phase voltage Ve4is the voltage of the winding in which the windings99and9A are wound in series, and is the voltage Ve4inFIG.13, which is a voltage whose phase is 48° behind the A4 phase voltage Va4. The respective voltages of these phases satisfy a relationship of formulas (1) to (12). The same formula applies to the D phase and the E phase. However, it is a mathematical formula that holds under the above-mentioned various simplified conditions. Further, the values of each voltage, each current, and each torque are normalized by the formulas (5), (9), (10) and the like. The A4 phase voltage Va4, the B4 phase voltage Vb4, the C4 phase voltage Vc4, the D4 phase voltage Vd4, and the E4 phase voltage Ve4described with reference toFIG.13have the relationship of the formula (5). Then, as the A phase torque is proportional to the A phase voltage in the formula (8), the A4 phase torque Ta4, B4 phase torque Tb4, C4 phase torque Tc4, D4 phase torque Td4, and E4 phase torque Te4related to the reluctance motor ofFIG.9(a)has a constant value of (Io/Vso), and it is proportional to each phase voltage Va4, Vb4, Vc4, Vd4, and Ve4, respectively. In that sense, the phase torques Ta4, Tb4, Tc4, Td4, and Te4are added below the phase voltages Va4, Vb4, Vc4, Vd4, and Ve4inFIG.13. Next, a method of generating continuous torque in the positive direction in the CCW direction by the reluctance motor shown inFIG.9(a),FIG.12andFIG.13will be described. In the section where Ta4, which is the A4 phase torque ofFIG.13, generates a positive torque, θr is 0° to 24°, 60° to 84°, and the like, and the current shown in Ia4F ofFIG.13is energized. Here, for example, when θr is −9° to 0° and between 24° and 33°, the winding voltage Va4is 0, so that there is no influence on the torque, and the current is used as an increase time and a decrease time. The same applies to other current cycles of Ia4F. In the section where Tb4, which is the B4 phase torque inFIG.13, generates a positive torque, θr is 12° to 36°, 72° to 96°, and the like, the current Ib4F whose phase is delayed by 12° with respect to Ia4F inFIG.13is energized. In the section where Tc4, which is the C4 phase torque inFIG.13, generates a positive torque, θr is 24° to 48°, 84° to 108°, and the like, the current Ic4F whose phase is delayed by 24° with respect to Ia4F inFIG.13is energized. In the section where Td4, which is the D4 phase torque inFIG.13, generates a positive torque, θr is 36° to 60° and 96° to 120°, and the current Id4F whose phase is 36° behind Ia4F inFIG.13is energized. In the section where Te4, which is the E4 phase torque inFIG.13, generates a positive torque, θr is 48° to 72° and 108° to 132°, and the current Ie4F whose phase is 48° behind Ia4F inFIG.13is energized. The sum of the positive torques of each phase at this time is the torque shown in131so of Vt4inFIG.13, which is a constant value of a magnitude of 1.5. At all times, two of the five phases are generating torque, and the sum is 1.5. Next, a method of generating torque in the CW direction while rotating at a speed Vso in the CCW direction with the reluctance motors ofFIGS.9A,12and13will be described with reference toFIG.13. It is also an operation that brakes the motor and regenerates it. In the section where Ta4, which is the A4 phase torque inFIG.13, generates a negative torque, θr is 33° to 51° and 93° to 111°, and the like, and the trapezoidal current shown by the solid line of Ia4R inFIG.13is energized. Here, for example, when θr is −9° to 0° and between 24° and 33°, the winding voltage Va4is 0, so that there is no influence on the torque, and the current is used as an increase time and a decrease time. The same applies to other current cycles of Ia4R. In the section where Tb4, which is the B4 phase torque inFIG.13, generates a negative torque, θr is 45° to 63° and 105° to 123°, and the like, and the current Ib4R whose phase is delayed by 12° with respect to Ia4R inFIG.13is energized. In the section where Tc4, which is the C4 phase torque inFIG.13, generates a negative torque, θr is 57° to 75° and 117° to 135°, and the like, and the current Ic4R whose phase is delayed by 24° with respect to Ia4R inFIG.13is energized. In the section where Td4, which is the D4 phase torque inFIG.9, generates a negative torque, θr is 69° to 87°, 129° to 147°, and the like, and the current Id4R whose phase is 36° out of phase with that of Ia4R inFIG.9is energized. In the section where Te4, which is the E4 phase torque inFIG.9, generates a negative torque, θr is 21° to 39° and 81° to 99°, and the like, and the current Ie4R whose phase is 48° behind Ia4R inFIG.9is energized. The sum of the torque values of the respective phases is the value shown in132of Tt4inFIG.13, and has a torque characteristic in which the values of −1.0 and −2.0 are repeated every 9°. The average torque is −1.5, which is the same magnitude as the positive torque. However, this characteristic has a large torque pulsation, which Is not preferable from the viewpoint of noise and vibration. As one of the countermeasures, there is a method in which the current energization method is a trapezoidal current waveform shown by a broken line in1a4R ofFIG.13. By making the current waveform of each phase into this trapezoidal waveform, the negative torque of the reluctance motor inFIG.13has a torque characteristic of a constant value of magnitude −1.0. As a result, the torque pulsation becomes zero. Further, in terms of current control, it is possible to create an increase time and a decrease time of the current, so that the difficulty in current control can be solved. Note that Vt4inFIG.13corresponds to the sum of the torques of each phase, and is a virtual voltage obtained by adding the operating voltages of the respective phases. Further, in principle, although the algorithm for generating the torque in the CW direction can be generated regardless of the rotation direction and the rotation speed, the CW torque at the time of CCW rotation has been described, for the convenience of explaining the CCW torque in comparison withFIG.13. The reluctance motor of the present invention shown inFIGS.9(a),12and13has unique characteristics as described above. To solve the problem of noise, for example, a method of Increasing each phase current such as the A4 phase current Ia4F inFIG.13in the first half of each cycle and decreasing the current value in the latter half can be considered. Since the torque of each phase overlaps with the torque of the other phase, the two phases complement each other in the first half and the second half. Specifically, for example, the A4 phase current Ia4Is made large from 0° to 12° of the rotor rotation angle θr inFIG.13, and is made small from 12° to 24°. Similarly, at this time, the B4 phase current Ib4is increased from 12° to 24° and decreased from 24° to 36°. Similarly, the C4 phase current Ic4is increased from 24° to 36° and decreased from 36° to 48°. Similarly, the D4 phase current Id4should be large from 36° to 48° and small from 48° to 60°. Then, the E4 phase current Ie4is made large from 48° to 60° and small from 60° to 72°. In this way, the current energization method of each phase, that is, by modifying the magnitude of the current and reducing the current change rate when the current of each phase decreases from a large current value to 0 [A], it is possible to reduce the rate of change of the radial suction force, reduce the vibration of the back yoke, case, etc. of the motor, and reduce the noise. Further, since the current waveforms Ia4F and Ia4R inFIG.13can be trapezoidal current waveforms, noise can be reduced by suppressing the current change rate such as a rapid increase or decrease of each phase current. Further, as for the torque of each phase, the torque is always generated by two phases. In this way, by generating torque in a section where the stator magnetic poles of each phase are wide and by overlapping the torque generating sections with each other in the three phases, smoother rotation can be realized and noise can be reduced. Further, focusing only on the positive torque portion of Ta4inFIG.13, smoothing the stepped torque waveform and estimating the fundamental wave component, the shape is close to a sine wave squared formula (1−COS(2θ))/2. Therefore, the positive torque of each phase inFIG.13is close to the torque of a synchronous motor driven by a 5-phase sine wave, even though it is a reluctance motor driven by a current having a substantially square wave shape, and It can be expected to reduce noise and vibration. Further, as described above, the total positive torque of the reluctance motor ofFIG.10is also a constant value shown in131of Tt4ofFIG.13. The copper loss in the driving method ofFIG.13will be described. When rotating to CCW, the current of each phase energizes the current at 40% of the pre-energized section, and the copper loss increases as compared with the case of 33% of the energized section of the conventional method ofFIG.47. Priority is given to the quietness of the motor. A method for significantly reducing copper loss and a method for increasing torque of the motor of the present invention will be described later. Further, the shape of each rotor magnetic pole shown inFIG.12can be deformed into various shapes. For example, the staircase shape can be made smoother. Further, since each torque characteristic can be created by the relative magnetic characteristics of the stator magnetic pole and the rotor magnetic pole, not only the rotor magnetic pole shape but also the stator magnetic pole shape can be deformed. It is also possible to skew the rotor or stator. Fifth Embodiment Next, an embodiment of claim2will be shown and described with reference toFIGS.1,14, and15. The cross-sectional view1of the reluctance motor will be described in common withFIGS.4,6and14. The expression methods ofFIGS.14and15are the same as those ofFIGS.4,5,6, and7. Here, the description of the expression method and the like will be omitted. The shape of the rotor magnetic pole of the reluctance motor shown inFIG.14has a portion having an axial length of Ls/3, a portion having an Ls×⅔ portion, and a portion having an Ls portion, and has a shape having three stages of axial length. The characteristic of this rotor magnetic pole is that the circumferential range of the torque generated by one rotor magnetic pole can be three times wider than the circumferential width of the stator magnetic pole, and the torque generation ratio of each phase is high and the torque can be generated in the rotation range of ⅔. FIG.14(a)shows the shape of the inner peripheral surface of the stator magnetic pole SP as seen from the air gap surface between the stator and the rotor, and the circumferential direction of the CCW is the horizontal axis direction ofFIG.14, that is, it is a figure developed linearly so as to be in the right direction of the paper surface ofFIG.14. The vertical axis direction of the paper surface ofFIG.14is the direction of the rotor axis. InFIG.14,141is an A5 phase stator magnetic pole,142is an A5/ phase stator magnetic pole,143is a B5 phase stator magnetic pole,144is a B5/ phase stator magnetic pole,145is a C5 phase stator magnetic pole, and146is a C5/ phase stator magnetic pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 20° and a rotor axial length of Ls. InFIG.14B, the shape of the outer peripheral surface of the rotor magnetic pole RP as seen from the air gap surface is such that the circumferential direction of the CCW inFIG.1is the horizontal axis direction inFIG.14, that is, it is a figure developed linearly so as to be in the right direction of the paper surface ofFIG.14. The value of the rotor rotation angle position θr is shown at the bottom ofFIG.14. Θr inFIG.14(b)is 0°. It should be noted that this θr indicates from −80° to 360°. The rotor magnetic pole14J ofFIG.14Bis the same as the rotor magnetic pole1J ofFIG.1, and the rotor rotation angle position θr is 0°. The circumferential angular width θBr of each rotor magnetic pole inFIG.14is 65°. Four rotor magnetic poles of14J,14K,14L, and14M are arranged in a range of 360 degrees. The shape of each rotor magnetic pole is in the CCW direction, and the front portion in the right direction on the paper ofFIG.14has a circumferential angular width of 20° and a rotor axial length of Ls/3, as shown in the figure. The middle portion of the rotor magnetic pole has a circumferential angular width of 20° and a rotor axial length of Ls×⅔. The rear portion of the rotor magnetic pole has a circumferential angular width of 25° and a rotor axial length of Ls. FIG.14(c)shows a rotor shape rotated by 20° from the rotor position ofFIG.14(b)to CCW. At this time, θr is 20°.FIG.14(d)is further rotated by 20° to CCW, and θr is 40°.FIG.14(e)is further rotated by 20° to CCW, and θr is 60°.FIG.14(f)is further rotated by 5° to CCW, and θr is 65°.FIG.14(g)is further rotated by 20° to CCW, and θr is 85°. By rotating the rotor in this way and changing the rotor rotation angle position θr, the magnetic relative relationship between each rotor magnetic pole RP and each stator magnetic pole SP changes. Therefore, the current can be applied to each phase winding of each stator magnetic pole SP at an appropriate timing to excite it, and a rotor rotation torque can be obtained. Now, the A5 phase concentrated winding winding147and the A5/ phase concentrated winding winding148are connected in series with the same polarity, and consider a state in which the rotor is rotated to CCW at a constant speed Vso while a constant current Io having a value dose to the continuous rating is energized as the A5 phase current Ia5. The CCW direction ofFIG.1is the right direction of the paper surface ofFIG.14. The winding voltage at this time is the voltage Va5inFIG.15. The horizontal axis of Va5is time t, and the value of the rotor rotation angle position θr at that time is shown at the bottom ofFIG.15. First, when the rotor magnetic pole14J approaches from 0° to 20° of θr, the front portion of the rotor magnetic pole14J faces the A5 phase stator magnetic pole141via an air gap. This show the state Initiated in a part (b) to a part (c) ofFIG.14. The rotor axial length of the front portion of the rotor magnetic pole14J is ⅓ of the axial length Ls of the stator magnetic pole, and the rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole is ⅓ of the maximum value. The value between 0° and 20° of Va5inFIG.15is shown as 0.333. Next, when the rotor magnetic pole14J approaches 20° to 40° of θr as shown inFIGS.14(c) to14(d), the Intermediate portion of the rotor magnetic pole14J faces the A5 phase stator magnetic pole141. The axial length of the intermediate portion of the rotor magnetic pole14J is Ls×⅔, and the rotational change rate of the magnetic flux passing through the intermediate portion of the rotor magnetic pole and the stator magnetic pole is ⅔ of the maximum value. However, at the same time, the front portion of the rotor magnetic pole14J deviates from the stator magnetic pole141. The value between 20° and 40° of Va5inFIG.15is shown as subtraction (⅔−0.333)=0.333. When the rotor magnetic pole14J approaches from 40° to 60° of θr as shown inFIGS.14D to14E, the rear portion of the rotor magnetic pole14J faces the stator magnetic pole141. On the other hand, the intermediate portion of the rotor magnetic pole14deviates from the stator magnetic pole141. The value between 40° and 60° of Va5inFIG.15is shown as subtraction (1−⅔)=0.333. As shown inFIGS.14(e)to14(f), the entire surface of the stator magnetic pole141faces the rotor magnetic pole14J while the rotor magnetic pole14J is between 60° and 65° of θr. The rotational change rate of the magnetic flux passing through the stator magnetic pole141is 0, and the value of Va5inFIG.15during this period is 0. As shown inFIGS.6(f) to16(g), the rear portion of the rotor magnetic pole14J deviates from the stator magnetic pole141while the rotor magnetic pole14J is between 65° and 85° of θr, so the rotational change rate of the magnetic flux passing through the stator magnetic pole141is −1, and the value of Va5inFIG.15during this period is −1. When the rotor rotation angle position θr is from 85° to 90°, there is no rotor magnetic pole facing the stator magnetic pole141, and the value of Va5inFIG.15is 0. When θr becomes 90°, the rotor magnetic pole14K approaches the stator magnetic pole141, the state returns to the initial state of the operation described in the state of (b) ofFIG.14, the operation is repeated, thereby continuously rotating in the CCW direction. Similarly, the B5 phase windings143and144ofFIG.14and the B5/ phase windings are connected in series, and the rotor is rotated to the CCW at a constant speed Vso with a constant current Io as the B5 phase current Ib5. The winding voltage at this time is the voltage Vb5shown inFIG.14. Similarly, the C5 phase windings145and146and the C5/ phase windings are connected in series, and the rotor is rotated to the CCW at a constant speed Vso in a state where a constant current Io is applied as a C5 phase current Ic5. The winding voltage at this time is the voltage Vc5shown inFIG.14. The voltages Va5, Vb5, and Vc5have a phase difference of 30° from each other. The A5 phase voltage Va5, the B5 phase voltage Vb5, and the C5 phase voltage Vc5described with reference toFIG.15correspond to the formulas (5), (9), and (10). Then, from the formulas (8), (11), and (12), (Io/Vso) is a constant value for each phase torque Ta5, Tb5, and Tc5related to the reluctance motor ofFIG.14, so it is proportional to each phase voltage Va5, Vb5, Vc5, respectively. In that sense, the phase torques Ta5, Tb5, and Tc5are added in parentheses below the phase voltages Va5, Vb5, and Vc5inFIG.15. However, it is a mathematical formula that holds under the above-mentioned various simplified conditions. Further, the values of each voltage, each current, and each torque are normalized by the formulas (5), (9), (10) and the like. Next, a method of generating continuous torque in the positive direction in the CCW directions with the reluctance motor ofFIG.14will be described. In the section where Ta5, which is the A5 phase torque ofFIG.15, generates a positive torque, θr is 0° to 60° and 90° to 150°, and the current shown in Ia5F ofFIG.15is energized. As described above, the section where the A5 phase Va5is 0 [V] is between 60° and 65° of the rotor rotation angle position θr and between 85° and 90°, so it can be used as the increase time and decrease time of the A5 phase current Ia5F. Therefore, the current can be trapezoidal as shown in Ia5F ofFIG.15. In the section where Tb5, which is the B5 phase torque inFIG.15, generates a positive torque, θr is 30° to 90° and 120° to 180°, and the current Ib5F whose phase is delayed by 30° with respect to Ia5F inFIG.15is energized. In the section where Tc5, which is the C5 phase torque inFIG.15, generates a positive torque, θr is 60° to 120° and 150° to 210°, and the current Ic5F whose phase is delayed by 60° with respect to Ia5F inFIG.15is energized. When the positive part of the torque Ta5of the A5 phase, the positive part of the torque Tb5of the B5 phase, and the positive part of the torque Tc5of the C5 phase are added, it becomes 151 of Tt5inFIG.15. The torque of each of the three phases has a characteristic of overlapping by 30°, and the rotor shape is such that when the torques of the three phases are added, the torque becomes constant. Next, a method of generating torque in the CW direction in a state where the reluctance motor ofFIG.14rotates at a speed Vso in the CCW direction will be described with reference toFIG.15. It is also an operation that brakes the motor and regenerates it. The section in which Ta5, which is the A5 phase torque inFIG.15, generates a negative torque is between 65° to 85° and 155° to 175° of θr, and the value of Ta5inFIG.15is −1. During this time, the A5-phase current Ia5R shown inFIG.15is energized. Since the rotor rotation angle position θr between 60° and 65° and between 85° and 90° is a section where the A5 phase voltage Va5is 0 [V], it can be used as the increase time and decrease time of the A5 phase current Ia5R, and can be a trapezoidal current. Similarly, as the B5 phase current Ib5, a current whose phase is delayed by 30° from Ia5R inFIG.15is energized. Similarly, as the C5 phase current Ic5, a current whose phase is delayed by 60° from Ia5R inFIG.15is energized. The sum of the negative torques of each phase is the value shown in152of Tt5inFIG.15, and repeats a cycle in which ⅔ of 20° is −1.0 and ⅓ of 10° is 0. The average value is −⅔. If this torque ripple becomes a problem, various measures such as correction of the rotor magnetic pole shape, correction of the stator magnetic pole shape, and skew can be made. Note that Vt2inFIG.15corresponds to the sum of the torques of each phase, and is a virtual voltage obtained by adding the operating voltages of the respective phases. Further, although the torque in the CW direction can be generated in principle regardless of the rotation direction and the rotation speed, the CW torque at the time of CCW rotation has been described for the convenience of explaining the CCW torque with reference toFIG.15. The motor of the present invention shown inFIGS.1,14, and15has unique characteristics as described above. For the problem of noise, for example, a method of increasing the current of each phase inFIG.15in the first half and decreasing the current value in the second half can be considered. Specifically, for example, the A5 phase current Ia5Is made large from 0° to 30° of the rotor rotation angle θr inFIG.15, and Ia5is made small from 30° to 60°. Similarly, at this time, the B5 phase current Ib5is increased from 30° to 60°, and Ib5is decreased from 60° to 90°. Similarly, the C5 phase current Ic5is increased from 60° to 75° and decreased from 90° to 120°. In this way, the current energization method of each phase, that is, modifying the magnitude of the current to reduce the current change rate when the current of each phase decreases from a large current value to 0 [A], it is possible to reduce the rate of change of the radial suction force, reduce the vibration of the back yoke, case, etc. of the motor, and reduce the noise. Further, as shown inFIG.15, the torque of each phase generates torque in a section of 67%. Two of the three phases always generate torque. In this way, by generating torque in a section where the stator magnetic poles of each phase are wide and by overlapping the torque generating sections with each other in the three phases, smoother rotation can be realized and noise can be reduced. Further, since the current waveform Ia5F inFIG.15can be a trapezoidal current waveform, noise can be reduced by suppressing the current change rate such as a rapid increase or decrease of each phase current. The copper loss in the driving method ofFIG.15will be described. When rotating to CCW, the current of each phase energizes the current at 67% of the pre-energized section, and the copper loss increases as compared with the case of 33% of the energized section of the conventional method ofFIG.47. Priority is given to the quietness of the motor. A method for significantly reducing copper loss and a method for increasing torque of the motor of the present Invention will be described later. Next, with respect to the outer peripheral surface shape of the rotor magnetic poles shown inFIGS.4,6,10,12, and14, a linear development view of a modified example thereof will be described with reference toFIG.16.FIG.16(a)shows an example of the rotor magnetic pole, in which the right side of the paper is the direction of rotation of the CCW, the rotor axial width of the front portion of the rotor magnetic pole is161and the circumferential angular width of the front portion is163, the rotor axial width of the rear portion of the rotor magnetic pole is162. The rotor axial width161of the front portion can be reduced or Increased as shown inFIG.16(b), depending on the desired motor characteristics. The same applies to the circumferential angle width163. Further, the rotor axial width161of the front portion may be tapered as shown by a reference sign165ofFIG.16(c)or may be tapered as shown by a reference sign166ofFIG.16(d). Further, the shape of the rotor magnetic pole on the CW side can be deformed into various shapes such as shown by a reference sign167. Sixth Embodiment Next, an embodiment of claim3will be shown and described with reference toFIG.17. InFIGS.4,6,10,12, and14, an example is shown in which the length in the rotor axial direction is changed between the front portion and the rear portion of the rotor magnetic pole as a means for changing the magnetic resistance value MR in the radial direction over the entire area of the rotor magnetic pole portion RP in the rotor axial direction. The lengths Ls and Ls/2 of the rotor magnetic poles in each figure in the rotor axial direction are shown, and the shape of the rotor magnetic poles on the rotor surface is shown horizontally expanded. The rotor magnetic pole shape that changes the length in the rotor axial direction is one method of arbitrarily setting the magnetic resistance MR of the rotor magnetic poles at the positions in the circumferential direction as viewed from the stator side. Easy to understand visually. However, from the viewpoint of ease of motor production, cost, noise, iron loss, and wind loss, it is possible to change the magnetoresistance value MR in the radial direction of the rotor magnetic pole by other methods. In the reluctance motor of the present invention, the rotor magnetic pole shape as shown inFIG.17can be applied. FIG.17shows an example of processing an electromagnetic steel sheet into various shapes. Electromagnetic steel sheets are laminated to form a rotor core, which constitutes the rotor magnetic pole of a reluctance motor. The thickness of the rotor magnetic pole in the rotor axial direction is uniform and Is Ls.FIG.17Ashows an example in which the rotor ofFIG.1is deformed. Reference sign173is an electromagnetic steel sheet, and reference sign172is a soft magnetic material having a smaller saturation magnetic flux density than the portion of173. For example, it is a ferrite iron core or a stainless electromagnetic steel sheet. Reference sign17J is a holding portion for holding the soft magnetic material172.171is a space. The saturation magnetic flux passing in the radial direction can be limited by the magnetic properties of the material. With such a configuration, it is possible to realize electromagnetic characteristics similar to those of the rotor magnetic pole ofFIG.4. What is important in the reluctance motor of the present invention is not the reluctance in the small exciting current region but the magnitude of the magnetic flux in the exciting current region such as the continuous rated current Irate of the reluctance motor or the maximum current Imax. It is the magnitude of the magnetic flux in the radial direction including the material and shape of the rotor magnetic pole. By limiting the magnitude of the magnetic flux in the radial direction at each circumferential position of the rotor, various torque characteristics and electromagnetic characteristics can be realized. For example, the characteristic of the broken line inFIG.3Ashows the same relative permeability as the solid line in the region where the exciting current is small. Therefore, when the magnetic material having the characteristic of the broken line is used as the material of172inFIG.17, the magnetic resistance values of172and173in the radial direction are the same in the region where the exciting current is small. It does not have the characteristics described inFIG.5. However, in the current region where the exciting current is such as Irate and Imax, the characteristic of the broken line is about ½ times the characteristic of the solid line, and the passing magnetic flux in the radial direction can be limited. In this state, the characteristics described inFIG.5can be almost realized. Here, inFIG.172ofFIG.17, which is a portion of the rotor magnetic pole composed of the soft magnetic material having the above-mentioned characteristics of the broken line, the magnetic resistance value in the radial direction can be small because (magnetic flux/exciting current) is small in the region where the exciting current is large. This is an example of characteristics in which the magnetic resistance value in the radial direction is the same in the region where the exciting current is small, but different in the region where the exciting current is large. As described above, the rotor of the reluctance motor of the present invention can be realized in terms of both the shape of the rotor magnetic pole and the magnetic characteristics of the magnetic material. A reference sign17K inFIG.17(a)indicates an example in which a part of the electromagnetic steel sheet173is thinned by press working or the like. For example, by setting the thickness of the magnetic steel sheet of173to 0.35 mm and the thickness of the17K portion to 0.175 mm, the magnetic resistance value MR in the radial direction is halved, and the saturation magnetic flux passing in the radial direction can be limited to halved. With such a configuration, it is possible to realize electromagnetic characteristics equivalent to those of the rotor magnetic pole ofFIG.4. This17K configuration is excellent in productivity because it is possible to provide a thinning processing stage on the production line for press working of electrical steel sheets. In the case of this configuration, the holding portion17J is not required for centrifugal force, but there is a problem of fixing in the rotor axial direction, and as shown in17L, it is possible to devise such as leaving a part as a thick plate of 0.35 mm. Further, in laminating the electromagnetic steel sheets, for the purpose of holding, for example, about 1 in 20 disk-shaped electromagnetic steel sheets can be sandwiched. It is also possible to combine it with electromagnetic steel sheets of other shapes and stack them to obtain the desired electromagnetic characteristics and rotor strength. Further, in the17K configuration, it is possible to obtain electromagnetic characteristics for various purposes by changing the thickness of the steel plate such as a thick plate portion of 0.35 mm, a portion of 0.24 mm, and a portion of 0.12 mm. InFIG.17(b), a large hole174and an elongated slit-mounted hole175are machined in the electrical steel sheet176. The portion174is electromagnetically substantially equivalent to the spatial portion between the rotor magnetic poles inFIG.4. The portion where the slit of175is arranged is electromagnetically equivalent to the portion where the length in the rotor axial direction is Ls/2 at the front portion of the rotor magnetic pole inFIG.4. The slit of175has a large magnetic resistance in the circumferential direction and is configured to be about doubled in the radial direction. This slit shape is a pointed triangle, and the magnetic path sandwiched between the slits has a uniform width. In this way, it is possible to limit the maximum value of the radial magnetic flux by performing various hole drilling on the electrical steel sheet. The hole shape can be various shapes such as a square hole, a triangular hole, a round hole, and an elliptical hole, and the number, size, and distribution of holes can also be various. It can be expected to reduce eddy current loss and hysteresis loss, and has excellent magnetic characteristics. Further, it is also possible to limit the maximum value of the radial magnetic flux by laminating two or more kinds of electromagnetic steel plates having different shapes. In that case, effects such as averaging the discreteness of the magnetic resistance in the circumferential direction caused by the hole and averaging and complementing the rotor strength can be expected. It can also be combined with the above-mentioned thinning technique. Further, the outer circumference of the rotor inFIG.17(b)is circular, so that the noise of the rotor cutting the wind can be reduced. Further, electromagnetically, if the outer circumference of the rotor is circular, the harmonic component of the reluctance force can be reduced, and torque ripple and noise can be expected to be reduced. In order to reduce rotor vibration, each hole can be filled with resin or the like. FIG.17(c)is an example in which the magnetic characteristics of the rotor are realized by processing the outer peripheral portion of the electromagnetic steel sheet179to provide a recess. The recessed portion of178is expected to have the effect of reducing the magnetic flux, and177is a space portion. In this way, the electromagnetic steel sheet can be recessed to have characteristics that are electromagnetically close to those of the rotor magnetic pole shown inFIG.4. It can be manufactured by simple punching and laminating of electrical steel sheets, and the rotor is robust. Further, if the dust core is used, even a complicated three-dimensional shape combining the radial unevenness of the rotor and the unevenness in the rotor axial direction can be manufactured by the molding technology using a mold, and can improve productivity. Seventh Embodiment Next, an embodiment of claim4will be shown and described with reference toFIGS.18and19.FIG.18shows a shape in which the rotor surface shapes of each stator magnetic pole and each rotor magnetic pole are linearly developed, and shows the relationship of electromagnetic action at the rotor rotation angle position θr. The reluctance motor having the configuration shown inFIG.18aims to simply realize the motor characteristics shown inFIGS.6and7with different structures. FIG.18Ashows the shape of the inner peripheral surface of the stator magnetic pole SP as seen from the air gap surface between the stator and the rotor, and the circumferential direction of the CCW is the horizontal axis direction ofFIG.18, that is, it is a figure developed linearly so as to be in the right direction of the paper surface ofFIG.18. The vertical axis direction of the paper inFIG.18is the direction of the rotor axis. InFIG.18,181is an A6 phase stator pole,182is an A6/ phase stator pole,183is a B6 phase stator pole,184is a B6/ phase stator pole,185is a C6 phase stator pole, and186is a C6/ phase stator pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 30° and a rotor axial length of Ls. The concentrated winding187of the stator magnetic pole181and the concentrated winding188of182ofFIG.18are connected in series with the same polarity, and an A6 phase current Ia6is energized as an A6 phase winding, and the voltage is A6 phase voltage Va6. The concentrated winding18A of the stator magnetic pole183and the concentrated winding18B of184are connected in series with the same polarity, and a B6 phase current Ib6is energized as a B6 phase winding, and the voltage is a B6 phase voltage Vb6. The concentrated winding18D of the stator magnetic pole185and the concentrated winding18E of186are connected in series with the same polarity, and a C6 phase current Ic6is energized as a C6 phase winding, and the voltage thereof is a C6 phase voltage Vc6. The rotor magnetic poles18J,18K,18L, and18M shown inFIG.18Bare arranged in the circumferential direction. The rotor magnetic pole18J ofFIG.18Bhas a rotor rotation angle position θr of 0° and a circumferential angle width θBr of 52.5°. The rotor magnetic pole18L has a θr of (180°-15°)=165° and a circumferential angular width θBr of (52.5°-15°)=37.5°. The rotor magnetic pole18M has a rotor rotation angle position θr of 90° and a circumferential angle width θBr of 52.5°. The rotor magnetic pole18K has a rotor rotation angle position θr of (90°+180°−15°)=255° and a circumferential angle width θBr of (52.5°−15°)=37.5°. InFIGS.4,6,10,12, and14, a one-pole pair configuration is shown as an example of a configuration that is point-symmetric with respect to the center point of the rotor axis. However, the structure of the rotor magnetic poles inFIG.18is not a point-symmetrical structure. That is, the shapes of the rotor magnetic poles separated by an electric angle of 180° in the circumferential direction are not the same. For example, the rotor magnetic poles18J and18L do not have the same shape. Here, the rotor rotation angle position θr is indicated by an electric angle. When the motor has a single pole pair in the configuration ofFIG.18, for example, magnetic flux cannot pass through the stator magnetic pole181and the rotor magnetic pole18K, the rotor magnetic pole18L, and the stator magnetic pole182from (b) to (c) ofFIG.18. The operation is different from that ofFIGS.4,6,10,12, and14. As one of the countermeasures, there is a method of configuring two pole pairs or more. For example, as a two-pole pair, this is a method in which the N pole and S poles of the stator magnetic poles with a mechanical angle of 0° to 180° and the N pole and S poles of the stator magnetic poles with a mechanical angle of 180° to 360° have opposite polarities. FIG.19shows a cross-sectional view of the reluctance motor having the configuration ofFIG.18as a pair of two poles. Reference signs191and19N are A6 phase stator magnetic poles,192and19Q are A6/ phase stator magnetic poles,193and19E are B6 phase stator magnetic poles, reference signs194and19S are B6/ phase stator magnetic poles195and19R are C6 phase stator magnetic poles, and196and19P are C6/ phase stator magnetic poles. A concentrated winding shown by a broken line is wound around each stator magnetic pole. The directions of the windings of the stator magnetic poles are reversed so that the polarities of the north and south poles of the stator magnetic poles separated by 180° in mechanical angle are opposite polarities. As shown in the figure, concentrated winding windings are wound around the stator magnetic poles191and19N,192and19Q inFIG.19, and the currents are oriented and connected in series, and the A6 phase current Ia6is energized as the A6 phase winding, and the voltage is a B6 phase voltage Vb6. As shown in the figure, concentrated winding windings are wound around the stator poles195,19R,196, and19P, and the currents are oriented in series and connected in series, and the C6 phase current Ic6is energized as the C6 phase winding, the voltage is C6 phase voltage Vc6. The rotor shows an example of a configuration in which electromagnetic steel sheets are laminated, and a fan-shaped quadrangle such as19C or19D is a space in which an electromagnetic steel sheet is punched out and has a large magnetic resistance.19J and19T inFIG.19correspond to the rotor magnetic pole18J inFIG.18,19K and19Wcorrespond to the rotor magnetic pole18K inFIG.18,19L and19Vcorrespond to the rotor magnetic pole18L inFIG.18, and19M and19U correspond to the rotor magnetic pole18M of18. The rotor magnetic poles separated by 180° in mechanical angle are point-symmetrical and have the same shape. In this rotor configuration, since the outer circumference of the rotor is circular, the wind noise of the rotor is small, and the high-order harmonic components of the torque ripples are also reduced. As described above, since it is a pair of two poles, the stator magnetic poles separated by 180° in mechanical angle are the stator magnetic poles of the same phase, but the winding directions are opposite. This is also a stator pole that is 360° apart in electrical angle. For example, the B6 phase stator magnetic poles193and19E and the windings of the B6/ phase stator magnetic poles194and19S are connected in series to energize the B6 phase current Ib6. Since it has a point-symmetrical structure, the magnetic flux components shown by19F and19G can be generated without difficulties. Since the polarity of the stator magnetic poles is changed, the windings of the slots19A and19B have a positive current direction and a negative winding. Since the current polarity is different from that of other slots, care must be taken with other current energization methods described later. In the explanation ofFIG.19, it was shown that the generation of the magnetic flux component is not unreasonable by forming a point-symmetrical shape by pairing with two poles. Further, in the case of a 4-pole pair, if the polarities of the 2-pole pair are opposite, it is not unreasonable to generate magnetic flux, so that the configuration does not necessarily have to be point-symmetrical. Further, it will be described here that even in the case of the one-pole pair motor configuration in the configuration ofFIG.18, although it is not a point-symmetrical magnetic flux component, a necessary magnetic flux component can be generated and torque can be generated. For example, assuming that the A6 phase current Ia6is applied to the A6 phase stator magnetic pole181and the A6/ phase stator magnetic pole182, from (b) and θr=0° to (c) and θr=15° inFIG.18, the A6 phase stator magnetic pole181and the rotor magnetic pole18J gradually face each other, but the A6/ phase stator magnetic pole182and the rotor magnetic pole18L do not face each other, and the magnetic flux passing through181does not pass through182. However, at this time, the other C6/ phase stator magnetic pole186and the rotor magnetic pole18M are sufficiently opposed to each other, and the magnetic resistance is small. At the same time, the B6 phase stator magnetic pole183and the rotor magnetic pole18L are sufficiently opposed to each other, and the magnetic resistance is small. At the same time, the C6 phase stator magnetic pole185and the rotor magnetic pole18K are sufficiently opposed to each other, and the magnetic resistance is small. Therefore, the magnetic flux passing through181can pass through186,183, and185with a relatively small magnetic flux density. That is, the A6 phase stator magnetic pole181and the rotor magnetic pole18J can generate a torque close to that in the case ofFIG.19of the two-pole pair. The one-pole pair reluctance motor shown inFIG.18works well, although its action is not point-symmetrical. The following description of the magnetic flux of each phase, the voltage of each phase, and the torque of each phase will be described based on the linear development diagram ofFIG.18, but the generation of the magnetic flux component will be described assuming that the two-pole pair configuration ofFIG.19is assumed and the magnetic flux component is generated point-symmetrically. Now, the centralized winding187of the stator magnetic pole181and the centralized winding188of182ofFIG.18are connected in series with the same polarity, and a constant current Io having a value close to the continuous rating is energized as the A6 phase current Ia6, and consider a state in which the rotor is rotated to CCW at a constant speed Vso. The reluctance motor ofFIG.18is electromagnetically equivalent to the reluctance motor ofFIG.6, and has the same characteristics as the phase voltage and torque ofFIG.7ofFIG.6. Here,FIG.7will be diverted and described. The CCW direction of the reluctance motor ofFIG.18is the right direction of the paper surface ofFIG.18. First, when the rotor magnetic pole18J ofFIG.18approaches from 0° to 15° of θr, the rotor magnetic pole18J faces the A6 phase stator magnetic pole181via an air gap. The A6/ phase stator magnetic pole182and the rotor magnetic pole18L are not yet opposed to each other. It is the state of (b) to (c) ofFIG.18. For the A6 phase voltage Va6, the magnetic flux interlinking the winding187of the A6 phase stator magnetic pole181and the winding188of the A6/ phase stator magnetic pole182may be obtained from the formula (5) and its definition. At this time, the magnetic flux interlinking with the winding187is the magnetic flux passing through the stator magnetic pole181and the rotor magnetic pole18J, and the rotor axial width of both magnetic poles is Ls. The magnetic flux interlinking with the winding188is 0 because the stator magnetic pole182and the rotor magnetic pole18L are not yet opposed to each other. Considering these average values, it is equivalent to a state in which a rotor magnetic pole having a rotor axial width of Ls/2 is approaching both the stator magnetic pole181and the stator magnetic pole182. The magnetic flux interlinking both windings of187and188is equivalent to the magnetic flux on which the rotor magnetic pole having a rotor axial width of Ls/2 acts. Therefore, it can be said that the states (b) to (c) inFIG.18are electromagnetically equivalent to the states (b) to (c) inFIG.6. The A6 phase voltage Va6at this time is the same as the voltage Va2inFIG.7. Next, when the rotor magnetic pole18J approaches 30° from 15° of θr, the portion where the rotor magnetic pole183faces the stator magnetic pole181of the A6 phase increases by 15°. During this time, the A6/ phase stator magnetic pole182and the rotor magnetic pole18L also face each other via the air gap. During this time, the A6/ phase stator magnetic pole182and the rotor magnetic pole18L also face each other via the air gap. This state Is the state from (c) to (d) inFIG.18, and is electromagnetically equivalent to the state from (c) to (d) inFIG.18. Currently the A6 phase voltage Va6is the same as the voltage Va2inFIG.7. The same applies to the following, and the subsequent (d) inFIG.18is electromagnetically equivalent to the subsequent (d) inFIG.6. The A6 phase voltage Va6at this time is the same as the voltage Va2inFIG.7. As described above, since the period of the reluctance motor is 180° in the electric angle, the relationship between the stator magnetic pole and the rotor magnetic pole separated by 180° or 360° in the electric angle is electromagnetically equivalent if their average values are the same. The configuration ofFIG.18and the configuration ofFIG.6have such an equivalent relationship. The stator magnetic poles of both configurations are the same, and the average value of the rotor magnetic poles18J and18L inFIG.18, that is, the average shape is the rotor magnetic poles6J and6L inFIG.6. Then, the average value of the rotor magnetic poles18M and18K inFIG.18, that is, the average shape is the rotor magnetic poles6M and6K inFIG.6. However, the degree of distribution of torque generated by each stator magnetic pole, the degree of magnetic saturation, etc. are different, and the force acting inside the motor is also different. Further, comparing the shape of the motor and its manufacturability, the rotor configuration ofFIG.18is simpler than the rotor configuration ofFIG.6, and is excellent in productivity. Eighth Embodiment Next, an embodiment of claim5will be shown and described inFIGS.20,21,22,8,8(b), and9(b). In the cross-sectional view ofFIG.20, a configuration is shown in which the concentrated winding of each stator magnetic pole shown inFIG.1is converted into a full-pitch winding, and the two concentrated windings in each slot are integrated Into one winding. The purpose is to double the winding cross-sectional area in each slot and reduce copper loss in the slot. Others such as the rotor ofFIG.20have the same configuration as that ofFIG.1. It should be noted that the rotor magnetic pole configurations shown inFIGS.4,6and14increase the copper loss, which is also a technique for compensating for the increase in copper loss. AlthoughFIG.1is shared in the above description of some motors of the present invention, it is also shared as one of the typical motor forms in the description ofFIG.20and defined again as follows. InFIG.1,11is an A7 phase stator magnetic wire that winds17and18concentrated windings, and12is an A7/ phase stator magnetic pole that winds1C and1D concentrated windings, and both windings are connected in series in the same direction of current to energize the A7 phase current Ia7.13is a B7 phase stator magnetic pole that winds1U and1V concentrated windings, and14is a B7/phase stator magnetic pole that winds1S and1T concentrated windings, and both windings are connected in series in the same direction of current to energize the B7 phase current Ib7. Reference sign15is a C7 phase stator magnetic pole for winding1Q and1R concentrated windings, and16is a C7/ phase stator magnetic pole for winding1P and1N concentrated windings, and both windings are connected in series in the same direction of current to energize the C7 phase current Ic7. Then, for example, when the magnetic flux1E is generated, the A7 phase current Ia7is energized. A reference sign201inFIG.20indicates an A7 phase stator magnetic pole, and202is an A7/ phase stator magnetic pole. The AB phase current Iab that energizes the winding207, its coil end20D, and the AB phase full-pitch winding indicated by winding208, and the winding20B, the coil end portion20F thereof, and the CA phase current Ica that energizes the CA-phase all-node winding wound indicated by the winding20C are energized to excite the A-phase magnetic flux pa shown by20G. A reference sign203indicates a B7 phase stator magnetic pole, while a reference sign204indicates a B7/ phase stator magnetic pole. The BC phase current Ibc that energizes the winding209, its coil end portion20E, and the BC phase full-pitch winding indicated by the winding20A, and the winding207and the current lab shown by208are energized to excite the B-phase magnetic flux φb shown by20H. A reference sign205indicates a C7 phase stator magnetic pole and206is a C7/ phase stator magnetic pole. The current Ica of the windings20B and20C and the current Ibc of the windings209and20A are energized to excite the C-phase magnetic flux φc shown by203. Here, the current ofFIG.1and the current ofFIG.20have the following relationship. Iab=Ia7+Ib7 (13) Ibc=Ib7+Ic7 (14) Ica=Ic7+Ia7 (15) As for the calculation method of each current inFIG.20, if each current value inFIG.1is calculated according to the formulas (13), (14) and (15) and energized,FIGS.20and1are electromagnetically equivalent. The same magnetic flux as in the case ofFIG.1is excited, and torque can be generated. At this time, for example, when the magnetic flux20G shown inFIG.20is generated, the A7 phase current Ia7may be energized as the AB phase current Iab, and the A7 phase current Ia7may be energized as the CA phase current Ica. At this time, comparing the A7 phase winding17inFIG.1and the CA phase winding207inFIG.20, assuming that the windings have the same number of turns in the same slot, there is also B7/ phase winding1S in the case ofFIG.1, so the winding cross-sectional area of the CA phase winding207can be relatively doubled. Therefore, the winding resistance can be halved in the full-pitch winding ofFIG.20, and the copper loss can be reduced when the same current is applied. Physically, the winding207ofFIG.20shares the exciting action of the winding17ofFIGS.1and1S. The winding207ofFIG.20can be used to excite the stator magnetic pole201, and can also be used to excite204. In the case of the energization method such as the conventional reluctance motor shown inFIGS.46and47, the energization time of each winding is 33% of the total. For example, the time for which the windings467and46G are energized at the same time is very short, and the effect of reducing copper loss by changing to a full-pitch winding is great. However, in the case of the energization method in which the time for energizing the windings467and46G at the same time is long, the copper loss reduction effect is reduced. Further, at the rotor axial end of each winding inFIG.20, a coil end portion of the winding as shown in20D,20E, and20F is required. In particular, in the case of a one-pole pair of motors, the motors are connected to slots 180 degrees apart at a mechanical angle, and the length of the coil end portion is a heavy burden in terms of production and efficiency. Here, as a countermeasure, if a two-pole pair is used as shown inFIG.22, the length of the coil ends221,222,223,224,225, and226can be shortened to about half. If a 4-pole pair is used, the circumferential length of the coil end is further halved, and the load on the motor can be reduced. Further, even in a mass-produced synchronous motor or the like, in the case of full-pitch winding, there is a problem that the winding becomes complicated due to the overlap of the phase windings of the coil end portion and the rotor axial length of the coil end portion becomes large. However, as shown inFIG.22, in the centralized winding in which the windings are concentrated in one slot in full-pitch winding, the overlapping of the windings is small, and a relatively simple winding configuration can be obtained. Further, in the case of an elongated motor having a large rotor axial length of the motor, the ratio of the coil end portion in all the windings is reduced. Next, the interlinkage magnetic flux and the winding voltage of the full-pitch winding winding ofFIG.20are shown and described inFIG.21. Note thatFIG.21will be described as a generalized motor configuration so that it can be applied not only to the motor ofFIG.20but also to the motor ofFIG.8(b),FIG.9(b), andFIG.23. Since the magnetic fluxes of other phases are also interlinked with the full-pitch winding winding ofFIG.21, the winding voltage has a complicated relationship. The causal relationship of voltage generation and its problems will be explained. In addition, due to the complexity of the interlinkage magnetic flux, not only the current control of the motor becomes complicated, but also the problem of voltage bias occurs, so that the voltage load of the inverter increases and the problem of increasing the size also occurs. A reference sign211inFIG.21shows an AX phase stator magnetic pole, and a reference sign212shows an AX/ phase stator magnetic pole. The winding213, the coil end214, the full-pitch winding W1of the winding215, and the winding216, the coil end217, and the full-pitch winding W2of the winding218are arranged, and it is assumed that the number of windings is Nwx. Reference signs219and21A show rotor magnetic poles. A reference sign21C shown by the broken line indicates a part of the rotor other than219and21A, in which the number of rotor magnetic poles is not limited. That is, this configuration can be applied to various types of motors. Here, as a limiting condition for the motors ofFIGS.20and21, it is assumed that the structure and configuration are point-symmetrical with respect to the center point of the rotor axis, and the currents energizing the windings W1and W2are currents as shown in formulas (13), (14), and (15) obtained by converting the current of the concentrated winding winding ofFIG.1into the current value of all the windings ofFIG.20. Under this condition, the magnetic fluxes generated inFIG.21are two types: magnetic fluxes φ1and φ2through which the AX phase stator magnetic poles211and212pass through the AX/phase stator magnetic poles212and magnetic fluxes crossing the magnetic fluxes as shown in φ3and φ4inFIG.21. Further, the magnetic fluxes of the other paths can be converted into these four magnetic fluxes. At this time, the voltage Vw1of the full-pitch winding W1and the voltage Vw2of the full-pitch winding W2are given by the following formulas. Vw1=Nwx×d(φ1+φ2+φ3+φ4)/dt(16) Vw2=Nwx×d(φ1+φ2−φ3−φ4)/dt(17) Vh=Nwx×d(φ3+<φ4)/dt(18) If there is no magnetic flux (φ3+φ4) crossing inFIG.21, the voltage Vh in formula (18) becomes 0, and Vw1and Vw2have equal values. However, if (φ3+φ4) exists, the voltage component Vh acts differentially on Vw1and Vw2, causing a phenomenon in which the voltage is biased. Normally, even in a reluctance motor having a relatively simple configuration as shown inFIG.20, the magnetic flux (φ3+φ4) inFIG.20is as large as the magnetic flux (φ1+φ2) and is greatly affected thereby. Moreover, since they act differentially, the voltage of one of Vw1and Vw2becomes small and the other becomes large, causing a large imbalance. This phenomenon occurs when the A7 phase current Ia7is applied to the concentrated windings17,18and1C and1D inFIG.1, only the magnetic flux1E interlinks with the concentrated windings, but when the winding is changed to a full-pitch winding, it means that the other crossing magnetic flux components (φ3+φ4) act like disturbance. As described above, although the configuration of the full-pitch winding winding shown inFIG.20can reduce the copper loss due to the current, Not only the voltage becomes complicated and the current control of the motor becomes complicated, but also the problem of voltage bias occurs due to the differential voltage component, which increases the voltage load of the inverter and causes a problem of increasing the size. In particular, there is a problem that an excessive voltage is generated when a heavy load is rotated at high speed. A method for solving this voltage problem will be described later with reference toFIG.37and the like. Ninth Embodiment Next, another embodiment of claim5is shown inFIG.8(b). The reluctance motors shown inFIGS.8(a) and8(b)are reluctance motors having 8 stator magnetic poles and 6 rotor magnetic poles, and the stator magnetic pole numbers inFIG.8(b)are the same, so they are omitted.FIG.8(b)shows the two windings of each slot ofFIG.8(a)described above integrated into one winding, and it is also a figure which shows the example which converts the centralized winding wound around each stator magnetic pole into the whole node winding. The voltage, current, drive circuit, etc. of each winding ofFIG.8(b)will be shown later. Tenth Embodiment Next, another embodiment of claim5is shown inFIG.9(b).FIG.9(b)is a combination of the two windings of each slot ofFIG.9(a)described above into one winding, and it is also a figure which shows the example which converts the concentrated winding which winds around each stator magnetic pole into full-pitch winding. InFIG.9A, as described above, in the slot between the A4 phase stator magnetic pole121and the C4/ phase stator magnetic pole126, a concentrated winding12J for energizing the A4 phase current Ia4and a concentrated winding96for energizing the C4 phase current Ic4are arranged. n the slot between the A4/ phase stator pole122and the C4 phase stator pole125, a concentrated winding92for energizing the A4 phase current Ia4and a concentrated winding95for energizing the C4 phase current Ic4are arranged. (Ia4+Ic4) is energized in both of these slots. However, the direction of the current is the direction of the current symbol. When the AC4 phase current (Ia4+Ic4) is applied to the full-pitch winding windings9B and9M ofFIG.9(b), the magnetomotive force generated by the currents of both slots is the same as that ofFIG.9(a). For the convenience of the drive circuit of the present invention, which will be described later, this AC4 phase full-pitch winding is divided into two insulated parallel windings, and the coil end is marked with two symbols,13ac1and13ac2. Similarly, the coil ends of the CE4-phase full-pitch winding wound in the slot between the C4 phase stator pole125and the E4/ phase stator pole12A are13ce1and13ce2, and (Ic4+Ie4) is energized. The coil ends of the EB4 phase full-pitch winding wound in the slot between the E4 phase stator pole129and the B4/ phase stator pole124are13eb1and13eb2, and EB4 phase current (Ie4+Ib4) is energized. The coil ends of the BD4 phase full-pitch winding wound in the slot between the B4 phase stator pole123and the D4/ phase stator pole128are13bd1and13bd2, and the BD4 phase current (Ib4+Id4) is energized. The coil ends of the DA4 phase full-pitch winding wound in the slot between the D4 phase stator magnetic pole127and the A4/ phase stator magnetic pole122are13da1and13da2, and DA4 phase current (Id4+Ia4) is energized. In this way, the configuration of the centralized winding ofFIG.9(a)can be converted to the full-pitch winding ofFIG.9(b). The actions, effects, and problems of the full-pitch winding motor ofFIG.9(b)are the same as those of the reluctance motor ofFIG.20described above. Eleventh Embodiment Next, an embodiment of claim6will be shown and described with reference toFIGS.23,24, and25. The cross-sectional view ofFIG.23shows a configuration in which the set of full-pitch winding windings shown inFIG.20is divided into two. It is a method of winding the winding for each slot individually. The stator magnetic pole and rotor magnetic pole inFIG.23are the same as those inFIG.20above. A reference237ofFIG.23shows the same as the AB phase winding207ofFIG.20, but is not a full-pitch winding, but is wound around the winding232outside the back yoke through the coil end portion234. A reference sign231shows the cross-sectional shape of the winding237, and a reference sign233shows an example of the cross-sectional shape of the winding232. The238ofFIG.23is also the same as the AB phase winding208ofFIG.20, but is not a full-pitch winding, but is wound around the winding23F outside the back yoke through the coil end portion23H. A reference sign23E shows the cross-sectional shape of the winding238, and a reference sign23G shows an example of the cross-sectional shape of the winding23F. The AB phase current Iab=(Ia+Ib) is energized through these AB phase windings237and238. Reference signs239and23A inFIG.23indicate BC phase windings, which are wound to the outside of the back yoke in the same manner as the AB phase windings237and238in FIG. A BC phase current Ibc=(Ib+Ic) is applied to these BC phase windings239and23A. Reference signed23B and23C inFIG.23indicate CA phase windings, and are wound outside the back yoke in the same manner as the AB phase windings237and238inFIG.23. A CA phase current Ica=(Ic+Ia) is applied to these CA phase windings23B and23C. When such each phase current is energized, each phase current ofFIG.23is generated inside the motor, and the magnetomotive force acting on the motor is the same as the magnetomotive force of each phase current ofFIG.2320. The form of these windings inFIG.23is a so-called toroidal winding. Next, the voltages of the AB phase windings237and238and the CA phase windings23B and23C ofFIG.23will be described with reference toFIG.21and (16), (17) and (18). The voltage of the winding237inFIG.23is Vw11, the voltage of238is Vw12, the voltage of23B is Vw21, and the voltage of23C Is Vw22. From the relationship between the position and the direction of each magnetic flux inFIG.21, it can be written as follows. Vw11=Nwx×d(φ1+φ3)/dt(19) Vw12=Nwx×d(φ2+φ4)/dt(20) Vw21=Nwx×d(φ1−φ4)/dt(21) Vw12=Nwx×d(φ2−φ3)/dt(22) Each of these voltages is a voltage different from the formulas (16), (17), and (18). Here, if the voltage when the windings237and238are connected in series is Vw1sand the voltage when the windings23B and23C are connected in series is Vw2s, the following formula can be written. The formulas (16) and (17) inFIG.21are the same, respectively. Vw1s=Vw11+Vw12=Nwx×d(φ1+φ2+φ3+φ4)/dt=Vw1(23)Vw2s=Vw11+Vw12=Nwx×d(φ1+φ2-φ3-φ4)/dt=Vw2(24) In comparison withFIGS.23and20, when the windings237and238ofFIG.23are connected in series, the voltage is the same as that of the full-pitch windings207and208ofFIG.20. When the windings239and23A ofFIG.23are connected in series, the voltage is the same as that of the full-pitch windings209and20A ofFIG.20. When the windings23B and23C ofFIG.23are connected in series, the voltage is the same as that of the full-pitch windings20B and20C ofFIG.20. Next, the features and effective usage when the winding structure as shown inFIG.23will be adopted will be described. One of the features is that since the windings of each phase are individually configured, there are no restrictions on current control, and various current controls can be performed. In addition, the winding can be simplified as compared with the full-pitch winding. A toroidal winding can be formed so as to surround the back yoke, which facilitates winding production and improves the winding space factor. In particular, when the number of phases increases as shown inFIGS.8and9, there is a problem that the winding of the coil end portion becomes complicated when the winding is a full-pitch winding. However, if it is a toroidal winding as shown inFIG.23, it is possible to simplify and increase the space factor without crossing the windings. Depending on the shape of the motor, there are advantages and disadvantages of the configuration shown inFIG.23. The rotor axial length of the motor is small, and the motor diameter is relatively large. In the case of a flat motor, the configuration ofFIG.23is advantageous. In the configuration ofFIG.23, the winding on the outer diameter side of the back yoke is not useful for generating the magnetomotive force inside the motor like the winding of the coil end portion inFIG.20. Therefore, one method of reducing the load on the outer diameter side winding is to apply it to a flat motor. Further, since the winding is exposed to the outer peripheral portion of the rotor, the cooling effect can be increased. The thermal conductivity of the conducting wire is high, and the heat of copper loss generated in the slot can be effectively dissipated to the outside. It is also possible to forcibly air-cool or liquid-cool the outside of the motor, or to add other heat dissipation means. Next,FIG.24shows an example in which the reluctance motor ofFIG.23has a flatter structure and has a characteristic configuration.FIG.24is a linear development of the circumferential shape seen from the outside ofFIG.23. The vertical direction of the paper surface inFIG.24is the rotor axial direction, and the horizontal direction of the paper surface is the direction in which the circumferential shape is linearly developed. The winding241ofFIG.24corresponds to the windings233and237ofFIG.23. The winding242corresponds to the winding23C ofFIG.23. The winding243corresponds to the winding239ofFIG.23. The stator magnetic pole244corresponds to the stator magnetic pole201ofFIG.23. The stator magnetic pole245corresponds to the stator magnetic pole206ofFIG.23. The left and right sides ofFIG.24are wavy lines, and the drawings are omitted. InFIG.24, a part of the back yoke of the stator is recessed in the rotor axial direction, and the winding is wound in the space. Lss is the rotor axial length of the stator, which is the same as the rotor axial length Ls inFIGS.20and23. Therefore, in the configuration ofFIG.24, the dimension of the coil end portion in the rotor axial direction can be shortened twice, so that a flatter reluctance motor can be realized. Since the length of each coil can be shortened, copper loss can be reduced and copper wire cost can be reduced. As mentioned above, external cooling is easy. When incorporating a motor into various devices such as electric vehicles, flat motors are often used. However, in order to secure the cross-sectional area through which the magnetic flux of the back yoke portion of the stator passes, it is necessary to slightly increase the diameter of the stator. In addition, since the shape of the soft magnetic material of the stator becomes complicated, it is necessary to devise a part thereof, such as using a dust core having an easy three-dimensional structure. Twelfth Embodiment Next, another embodiment of claim6is shown inFIG.25. Two sets of motors, which are an inner diameter side motor and an outer diameter side motor, are integrated and arranged in one motor. The motor configuration ofFIG.25is a configuration in which the motor configuration ofFIG.23is paired with two poles to form an inner diameter side motor, and an outer diameter side motor having a target structure for inner and outer diameters is added. InFIG.25, a reference sign25G shows the first rotor of the inner diameter side motor, and a reference sign25H shows the second rotor of the outer diameter side motor. A reference sign25E shows a part of the first stator of the inner diameter side motor, which is a B-phase stator magnetic pole. A reference sign25F shows a part of the second stator of the outer diameter side motor, and is a B-phase stator magnetic pole. The first stator and the second stator are arranged back to back, and the back yoke is integrated therewith. The back-to-back stator magnetic poles are in-phase stator magnetic poles, and the windings are toroidal windings in which the windings of the first stator and the windings of the second stator are integrated. The winding257serves as an AB phase winding, is wound around the winding251through the coil end portion252, and is wound so as to surround the stator core. These correspond to the windings237,234and232inFIG.23. The winding258also serves as also the AB phase winding, but the direction of this winding is opposite to that of the winding257, and the winding258is wound around the winding253through the coil end portion254and wound so as to surround the stator core. These correspond to the windings238,23H,23F inFIG.23. Similarly, the windings259and25A serve as BC phase windings that are wound around the stator core. These correspond to the windings239and23A inFIG.23. Similarly, the windings25B and25C serve as CA phase windings and are wound so as to surround the stator core. These correspond to the windings23B and23C inFIG.23.FIG.25shows a two-pole pair configuration, and the other half has the similar configuration. By adopting the motor configuration as shown inFIG.25, the windings232,23F, etc. on the outer side of the stator ofFIG.23can be effectively used as windings for generating torque. Further, since the inner diameter side of the motor space is also effectively utilized, the motor can have a high output density. Further, it is possible to have a stator configuration as shown inFIG.24, and it is also possible to flatten the motor. In particular, in a reluctance motor having a large number of phases as shown inFIGS.8(b) and9(b), the coil end portions become complicated in their structures when full-pitch windings are wound. Therefore, the coil end portions can be simplified in the structure, of which motor configuration can be provided as shown inFIG.25. Thirteenth Embodiment Next, an embodiment of claim7will be shown and described with reference toFIG.26.FIG.26is an enlarged view of the stator in the upper left portion ofFIG.19in which a permanent magnet is arranged between each tooth of the stator magnetic pole. A reference sign268indicates an outer shape of the stator. The reluctance motor shown inFIG.19has a two-pole pair of the reluctance motor ofFIG.1composed of six stator magnetic poles and four rotor magnetic poles. A reference sign261ofFIG.26shows an A6 phase stator magnetic pole, in which a concentrated winding is wound and an A6 phase current Ia6is energized in the direction indicated by the current symbol, so that the polarity becomes an S pole. A reference sign262shows an A6/ phase stator magnetic pole, the centralized winding is wound and the A6 phase current Ia6is energized in the direction indicated by the current symbol, so that the polarity becomes an N pole. A reference sign63denotes a B6 phase stator magnetic pole, in which a concentrated winding is wound and a B6 phase current Ib6is energized in the direction indicated by the current symbol, so that the polarity is an S pole. A reference sign266denotes a C6/ phase stator magnetic pole, in which a concentrated winding is wound and a C6 phase current Ic6is energized in the direction indicated by the current symbol, and the polarity becomes an N pole. A reference sign26A shows a permanent magnet placed between the teeth of the A6 phase stator pole261and the C6/ phase stator pole266, and the polarity of26A is in the direction of the polarity of both stator poles. A magnetic flux26B is generated in the direction opposite to the direction of the magnetic flux generated in the teeth of both stator magnetic poles. A reference sign26C shows a permanent magnet placed between the teeth of the C6/ phase stator pole266and the B6 phase stator pole263, and the polarity of26C is oriented in the direction of the polarity of both stator poles. A magnetic flux26D is generated in the direction opposite to the direction of the magnetic flux generated in the teeth of both stator magnetic poles. A reference sign26E shows a permanent magnet placed between the teeth of the B6 phase stator pole263and the A6/ phase stator pole262, and the polarity of26E is oriented toward the polarity of both stator poles. A magnetic flux26F is generated in the direction opposite to the direction of the magnetic flux generated in the teeth of both stator magnetic poles. It is assumed that Ltf is a circumferential width of each of the tooth tips of the stator magnetic poles261,262,263, and266shown inFIG.26. It is also assumed that the width of the tooth tip inFIG.19and the width of the slot opening are the same, the circumferential angle of the tooth tip is 15° in terms of mechanical angle. InFIG.19, the width of the tooth is a constant width from the tip of the tooth to the root, and the constant width corresponds to the Ltf. The constant width is the shape of each tooth shown by the alternate long and short dash line inFIG.26. However, the width of the central portion26G of the tooth inFIG.26is the tooth width of Lts shown by the solid line, and is smaller than the width Ltf. Therefore, the cross-sectional area of the slot is expanded by the cross-sectional integral with the tooth width reduced. As a result, the winding resistance in the slot can be reduced and the copper loss can be reduced. Now consider a magnetic flux φt that is part of the C6/ phase stator magnetic pole266and passes through the tooth center26G with a tooth width Lts. The relationship between the magnitude φt of the magnetic flux passing through the tooth center portion26G, the magnetic flux passing cross-sectional area St of the tooth center portion26G, the magnetic flux density Bt of the tooth center portion26G, the magnetic flux φpm generated by the permanent magnet, and the shape of the tooth will be described. Regarding the direction of the magnetic flux φt of the tooth center portion26G, the direction of the magnetic flux from the back yoke to the tip of the tooth is positive and the opposite direction is negative. It is assumed that the saturation magnetic flux density of the soft magnetic material constituting the stator and the rotor is 2.0 [T]. When the winding current is 0, the permanent magnets26A and26C supply a negative magnetic flux ppm to the tooth center portion26G. First, it is assumed that the tooth width Lts of the tooth center portion26G is equal to the tooth width Ltf of the tooth tip, and the permanent magnets26A and26C are not present. Hence, when the rotor magnetic pole is at the rotation angle position facing the C6/ phase stator magnetic pole266and the C6 phase current Ic6is excited at its maximum value, the magnetic flux densities of the tooth center26G and the tooth tip are 2.0 [T]. Next, it is assumed that the tooth width Lts of the tooth center26G is equal to the tooth width Ltf of the tooth tip, the permanent magnets26A and26C are sufficiently large, and the magnetic flux density Bt of the tooth center26G is −2.0 [T]. The magnetic flux φt passing through the tooth center portion26G is −2.0×St. Since this magnetic flux φt is in the direction opposite to the direction of the magnetic flux that the C6/ phase stator magnetic pole266excites with the C6 phase current Ic6, the tooth center portion26G is biased by the reverse magnetic flux. Now, when the rotor magnetic pole is at the rotation angle position facing the C6/ phase stator magnetic pole266and the C6 phase current Ic6is a current value capable of sufficiently exciting the magnetic circuit, the magnetic flux passing through the tooth tip is 2.0×St [Wb]. At this time, the magnetic flux density of the opposing rotor magnetic poles is 2.0 [T], and the magnets are magnetically saturated. The magnetic flux passing through the tooth center portion26G is (−2.0×St+2.0×St)=0. The magnetic flux density Bt of the tooth center portion26G is 0 [T]. As a result, in this state, magnetic flux is supplied from the permanent magnets26A and26C to the rotor side, and the magnetic flux passing through the tooth center portion26G becomes zero. Next, in a case where the tooth width Lts of the tooth center26G is as narrow as ½ of the tooth width Ltf of the tooth tip and it is assumed that the permanent magnets26A and26C are sufficiently large and the magnetic flux density Bt of the tooth center portion26G is −2.0 [T]. The magnetic flux φt passing through the tooth center portion26G is −2.0×(St/2)=−St. Now, when the rotor magnetic pole is at the rotation angle position facing the C6/ phase stator magnetic pole266and the C6 phase current Ic6is a current value capable of sufficiently exciting the magnetic circuit, the magnetic flux passing through the tooth tip is 2.0×St. The magnetic flux passing through the tooth center portion26G is (−St+2.0×St)=St [Wb]. The magnetic flux density Bt of the tooth center portion26G is (St/(St/2))=2.0 [T]. Therefore, it is shown that even if the tooth width Lts of the tooth center portion26G is reduced to ½ of the tooth tip, the rotor magnetic pole can be excited and torque can be generated for driving. By the way, the magnetic characteristics of the soft magnetic material are as shown inFIG.3(a), and have a relative permeability which is relatively large up to about 1.6 [T]. However, when the relative permeability approaches 2 [T], this permeability tends to decrease, and the iron loss tends to increase. Further, the characteristics of the permanent magnets26A and26C are not ideal, and the magnetic flux generated by the magnetomotive force of the C6 phase current Ic6is reduced. Therefore, when the above setting conditions are changed and the tooth width Lts of the tooth center portion26G is 80% of the tooth width Ltf of the tooth tip, it is assumed that the magnetic flux density Bt of the tooth center portion26G by the permanent magnets26A and26C is −1.6 [T]. The magnetic flux φt passing through the tooth center portion26G is −1.6×(0.8×St)=−1.28St [T]. Now, when the rotor magnetic pole is at the rotation angle position facing the C6/ phase stator magnetic pole266and the C6 phase current Ic6is a current value capable of sufficiently exciting the magnetic circuit, the magnetic flux passing through the tooth tip is 2.0×St. The magnetic flux passing through the tooth center portion26G is (−1.28×St+2.0×St)=0.72×St [Wb]. The magnetic flux density Bt of the tooth center portion26G is (0.72×St/(0.8×St))=0.9 [T]. Therefore, it is shown that even if the tooth width Lts of the tooth center portion26G is reduced to 80% of the tooth tip, the rotor magnetic pole can be excited and torque can be generated for driving. However, as described above, the magnetic flux generated by the permanent magnets26A and26C is reduced by the action of the magnetomotive force of the C6 phase current Ic6, so that the magnetic flux density Bt becomes a value larger than 0.9 [T]. As described, when using the method ofFIG.26, the tooth width Lts of the tooth center portion26G can be selected to have a width of 50% to 100% with respect to the circumferential width Ltf of the tooth tip of the stator magnetic pole. The magnetic characteristics and shape of the permanent magnets26A and26C can also be selected. As a result, it can be expected that the copper loss will be reduced by expanding the slot area, and the iron loss will be reduced by changing the magnetic operating points such as teeth and reducing the volume. If the tooth width Lts of the tooth center portion26G is 90% or less with respect to the circumferential width Ltf of the tooth tip of the stator magnetic pole, reduction of copper loss due to the expansion of the slot area can be expected. Further, when a large torque is output by the reluctance motor, there is a problem that a leakage flux is generated between the reluctance motor and the adjacent teeth in the circumferential direction due to a large exciting current. The permanent magnets26A,26C and the like also have the effect of reducing these leakage fluxes. Various designs are possible depending on the required motor characteristics. Here, an example of typical characteristics is shown. Further, each winding inFIG.26can be changed to a full-pitch winding. In the case of a synchronous motor or an induction motor, the magnetic resistance between the stator and the slot is reduced, and the discreteness of the magnetic resistance in the circumferential direction is reduced. Therefore, the slot opening width Lso inFIG.26is reduced. That is, the width Lts of the central portion26G of the tooth is usually smaller than the width in the circumferential direction of the tooth tip. However, a so-called switched reluctance motor, such as the motor of the present invention, uses the difference in magnetoresistance between the tooth portion and the slot opening to attract a part of the rotor to generate torque. Therefore, the size of the circumferential width of the tooth tip Ltf and the slot opening width Lso are almost equal. As for the width shape of the tooth, the width Ltf in the circumferential direction of the tooth tip and the width Lts of the central portion26G of the tooth are equal values. Further, considering the leakage flux flowing from the adjacent tooth in the circumferential direction, it is rather preferable that the width Lts of the central portion26G of the tooth is larger than Ltf. Fourteenth Embodiment Next, an embodiment of claim8will be shown and described with reference toFIGS.27and28. It is a configuration of a reluctance motor that uses two or more types of soft magnetic materials with different saturation magnetic flux densities. The non-linearity as shown inFIG.3(b)is improved, and the problem of torque saturation as shown inFIG.48is reduced. The soft magnetic material of the motor is mainly an electromagnetic steel plate for the motor, and the saturation magnetic flux density is close to 2.0 [T]. However, due to various circumstances, ferrite core with extremely small iron loss of about 0.4 [T], martensitic stainless electromagnetic steel sheet of about 0.8 [T] that is easy to bend, amorphous thin sheet of about 1.2 [T] with small iron loss, various materials such as a special steel sheet of permendur, which is expensive but can be used up to a magnetic flux density of about 2.4 [T], can be used. For the soft magnetic material MM1determined from the design conditions of a certain motor, the motor characteristics can be effectively improved by partially using another kind of soft magnetic material MM2having a large saturation magnetic flux density to the extent that no harmful effect occurs. FIG.27is a cross-sectional view of the motor having a configuration in which another member is added to a part ofFIG.1. The main soft magnetic material that constitutes most of the stator and rotor is MM1, and its saturation magnetic flux density is BM1. A reference sign271shows a stator magnetic pole portion made of a soft magnetic material MM2having a saturation magnetic flux density BM2 larger than that of the saturation magnetic flux density BM1. A reference sign272shows a rotor magnetic pole portion made of the soft magnetic material MM2. InFIG.27, the rotor magnetic pole portions271and272are shown only for one set of stator magnetic poles and rotor magnetic poles, but such portions271and272are similarly added to all stator magnetic poles and all rotor magnetic poles in the motor to which these are applied. FIG.28is a partial view ofFIG.6in which the upper left portion ofFIG.6is enlarged and the portions271,272, or273,274ofFIG.27is added. The reluctance motor ofFIG.27will be described in comparison with the characteristics shown inFIGS.6and7.FIG.28(a)is a linearly developed view of the circumferential shape of the stator magnetic pole. A reference sign11ofFIG.27shows an A2 phase stator magnetic pole and corresponds to the pole281ofFIG.28, a reference sign16shows a C2/ phase stator magnetic pole and corresponds to the pole286ofFIG.28, and a reference sign13shows a B2 phase stator magnetic pole and corresponds to the pole283ofFIG.28.FIG.28(b)is a linearly developed view of the circumferential shape of the rotor magnetic pole, and the rotor rotation angle position θr is 0°. Reference signs28A,28B and28C indicate the surface shapes of the rotor magnetic poles.FIG.28(c)is a diagram of the rotor rotation angle position θr=15° rotated by 15° from the state shown in the part (b) in the CCW direction, and corresponds to the rotor rotation angle position ofFIG.27. A reference sign271ofFIG.27shows a portion28P ofFIG.28, and a reference sign272ofFIG.27shows a portion28Q ofFIG.28. InFIG.28, in the region where the rotor rotation angle position θr is from around 5° to 15°, torque is generated between the C2/ phase stator magnetic pole286and the rotor magnetic pole28B. This rotation range is a rotation range in which θr corresponds to 20° to 30° in the characteristics ofFIG.48and is a region in which torque is significantly reduced due to magnetic saturation. Here, since the portions28P and28Q inFIG.28are composed of the soft magnetic material MM2, the saturation magnetic flux density is larger than that in BM2 and other portions, and the torque decrease as shown inFIG.48can be reduced. However, the place where the magnetic saturation in question occurs is not necessarily the tooth tip of the stator magnetic pole or the tooth tip of the rotor magnetic pole. Therefore, if there is a portion that is magnetically saturated in the magnetic flux cycle path, it is necessary to take measures such as thickening the magnetic path of that portion. In the region where the rotor rotation angle position θr inFIG.28is from around 5° to 15°, torque starts to be generated between the A phase stator magnetic pole281and the rotor magnetic pole28A, but in this rotation region, the magnetic flux is still small and the problem of magnetic saturation does not occur. As above, the CCW rotation has been described. For example, since the main-machine motor of an electric vehicle mainly uses the one-way rotation in the forward direction, one-way rotation torque is especially important. The foregoing soft-magnetic-material portions28P and28Q inFIG.28are thus useful when it is required to prioritize generation of the CCW torque. The stator magnetic pole portion273inFIG.27is a configuration example in which the stator magnetic pole portion271is enlarged in the circumferential direction. On the other hand, as for the rotor magnetic pole, the rotor magnetic pole portion274is a configuration example in which the rotor magnetic pole portion272is expanded in the circumferential direction and the soft magnetic material MM2is formed up to the CW end of the rotor magnetic pole. By adding the slightly larger stator magnetic pole portion273and rotor magnetic pole portion274to the motor, it is possible to reduce the decrease in torque more effectively than in the case of271and272. In this way, the size and arrangement location of the stator magnetic pole portion and the rotor magnetic pole portion can be selected. Fifteenth Embodiment Next, an embodiment of claim9is shown inFIG.29and described. This is a technique for improving motor efficiency by modifying the motor configurations shown inFIGS.1,8and9and utilizing permanent magnets to reduce the excitation load.291inFIG.29is an A8 phase stator pole,292is an A8/ phase stator pole,293is a B8 phase stator pole,294is a B8/ phase stator pole,295is a C8 phase stator pole, and296is a B8/ phase stator pole. InFIG.29, as compared with the configuration ofFIG.1described above, the B8 phase and B8/ phase stator magnetic poles are arranged in the opposite direction, the C8 phase C8/ phase stator magnetic poles are arranged in the opposite direction, each stator magnetic pole of the S pole is gathered on the upper side of the paper surface ofFIG.29, and each stator magnetic pole of the N pole is gathered on the lower side of the paper surface. Then, the permanent magnets29A and29B are inserted into the back yoke portion in the middle of them. The polar directions of the permanent magnets29A and29B are the polar directions of the stator magnetic poles. With these configurations, the permanent magnets29A and29B have a configuration in which all the stator magnetic poles are equally excited, and even if the rotor rotates, the fluctuation of the magnetic flux passing through the permanent magnets is relatively small. A soft magnetic bypass portion29C is provided on the side surface of the permanent magnet29A, and a soft magnetic bypass portion29D is provided on the side surface of the permanent magnet29B. In particular, when the motor is operated at a constant output at a high speed higher than the base rotation speed, the induced voltage exceeds the power supply voltage of the drive circuit due to the excessive magnetic flux of the permanent magnet, and there is a problem that the rotation speed is limited around the base rotation speed. For the purpose of relaxing this limitation of high-speed rotation, a part of the magnetic flux of the permanent magnet is short-circuited through the bypass portions29C and29D to reduce the magnetic flux acting as a motor. Further, in the absence of the permanent magnets29A and29B, at high speed rotation higher than the base rotation speed, it is necessary to bear the current and voltage for exciting the magnetic flux. As the rotation speed increases, the frequency also increases, and the exciting voltage corresponding to the leakage inductance becomes the voltage burden of the inverter. In the motor configuration shown inFIG.29, since the permanent magnets29A and29B bear a part of the excitation, the current burden and the voltage burden of the inverter can be reduced at high speed rotation. On the other hand, when the rotation speed is equal to or less than the base rotation speed and the motor torque is large, the maximum magnetic flux is required. The exciting current of each phase stator magnetic pole is also large, and magnetic flux is supplied to each stator magnetic pole through both the permanent magnets29A and29B and the bypass portions29C and29D. Here, it is necessary to set the magnetic path passage cross-sectional area of the bypass portions29C and29D to an appropriate value from the amount of magnetic flux that can pass through the bypass portions29C and29D, it can be designed together with the magnetic flux required for each stator magnetic pole and the magnetic flux generated by the permanent magnet. In the above description, it is assumed that the motor voltage is close to the DC power supply voltage when the maximum torque is output at the base rotation speed Nba. Therefore, at high speed rotation higher than the base rotation speed, it is necessary to limit the magnetic flux of the reluctance motor, which corresponds to the field weakening control in the synchronous motor. However, when the reluctance motor shown inFIG.29is used only at the base rotation speed or less, it is not necessary to weaken the field, so that the bypass portions29C and29D are unnecessary. Sixteenth Embodiment Next, an embodiment of claim10is shown inFIG.30. A reference sign301shows an A9 phase and302is an A9/ phase stator pole, a reference sign303shows a B9 phase, and a reference signs304shows a B9/ phase stator pole, a reference sign305shows a C9 phase, and a reference sign306shows a C9/ phase stator pole. The arrangement order is the same as that of the stator magnetic poles and rotor magnetic poles shown inFIG.20. Each winding of the stator also shows an example of a full-pitch winding inFIG.20. The back yoke ofFIG.30is spatially and magnetically divided into an S-pole back yoke307and an N-pole back yoke308as shown. The S pole stator poles301,303,305are connected to the S pole back yoke307, and the N pole stator poles302,304,306are connected to the N pole back yoke308through a portion such as a hole of the back yoke307. Permanent magnets309,30A,30B and the like for excitation are arranged between the back yoke307for the S pole and the back yoke308for the N pole. Each stator magnetic pole can be excited evenly. The N-pole stator poles302,304, and306are connected to the N-pole back yoke308through a portion such as a hole, avoiding the S-pole back yoke307. The portion is a portion Indicated by broken lines30D,30E, and30F, and intersects with the back yoke307for the S pole, is easily approached, and has a complicated shape. Leakage flux is likely to occur in these parts, and magnets for reducing leakage flux such as30G and30H are arranged. At this intersection, the cross-sectional area through which the magnetic flux passes tends to be small, and various measures such as widening in the circumferential direction are possible. One of these assembly methods can sequentially assemble many permanent magnets and soft magnetic cores as shown inFIG.30. In addition, as another manufacturing method, a material in which resin and magnet powder are mixed is liquefied to a high temperature and injected into both stator cores and a mold covering them, as in the case of molding a plastic part with an injection molding machine. In that case, even thin and complicated shapes such as permanent magnets30G and30H can be manufactured relatively easily. In addition, magnetization of each magnet can be performed by applying a magnetomotive force to both back yokes after assembly to magnetize a complicated magnet-shaped portion or the like all at once. Further, since the amount of magnetic flux required differs between high-speed rotation and large torque, the configuration shown in the bypass portions29C and29D inFIG.29may be added. That is, an appropriate amount of soft magnetic material may be arranged between the back yoke307for the S pole and the back yoke308for the N pole and connected by a part of the magnetic paths. In the case of the configurations ofFIGS.30and31, unlike the configuration ofFIG.29, the windings in the slots can be integrated into a full-pitch winding, or a toroidal winding as shown inFIG.23can be easily formed. Further, as shown inFIG.26, permanent magnets can be arranged between the teeth of the stator to expand the slot cross-sectional area, reduce the leakage flux between the teeth, and reduce the iron loss of the teeth. High torque can be achieved by reducing the excitation load of the reluctance motor, reducing copper loss, and expanding the slot cross-sectional area. Seventeenth Embodiment Next, another embodiment of claim10is shown inFIGS.31(a) and31(b).FIG.31is a side view of the stator core, and the vertical direction on the paper is the rotor axial direction. In the configuration ofFIG.31(a), there are an S-pole back yoke311and an N-pole back yoke312, and a permanent magnet313for excitation is sandwiched between them. As shown inFIG.30, the stator magnetic poles and rotors of each phase are arranged inside (a) ofFIG.31. The S-pole back yoke311is magnetically connected to the S-pole stator pole, and the N-pole back yoke312is magnetically connected to the N-pole stator pole. In this way, the permanent magnet313can excite the S-pole stator pole and the N-pole stator pole. In the configuration ofFIG.31(b), the back yokes for the S pole are arranged at314and316at both ends in the rotor axial direction. Reference numeral315is a back yoke for the N pole. Reference numerals317and318are permanent magnets arranged in the direction of the polarity of the back yoke. In this way, depending on the length of the motor in the rotor axial direction, a plurality of back yokes for S poles and back yokes for N poles can be arranged alternately. It is effective to arrange magnets for reducing leakage flux as shown in30G and30H inFIG.31at a portion where the N-pole stator magnetic pole and the S-pole stator magnetic pole are close to each other inFIG.31. Further, inFIGS.31(a) and31(b), the case where the permanent magnets313,317, and318have an annular shape is shown, but the magnetic path cross-sectional area from each back yoke to each stator magnetic pole may be expanded by forming an uneven ring in the rotor axial direction according to the arrangement and polarity of each stator magnetic pole. Eighteenth Embodiment Next, an embodiment of claim11will be shown and described with reference toFIGS.33and34.FIGS.33and34show a motor configuration in which torque ripple is small, noise is low, and torque can be easily increased at high speed rotation. The base rotation speed Nba is defined as the motor rotation speed at which the motor voltage becomes close to the DC power supply voltage when the maximum torque is output at the base rotation speed. This is a technology that involves the number of revolutions and the power supply voltage. This is to improve the fourth problem of the conventional reluctance motor described above, “difficulty in stable and uniform torque output at high speed rotation”. This problem of the conventional reluctance motors shown inFIGS.46and47is due to that since the width of the rotor magnetic pole in the rotor axial direction is uniform, when an exciting current is applied to the stator magnetic pole at a high speed rotation of the base rotation speed Nba or more, an excessive voltage close to the power supply voltage is generated, the current cannot be increased, and it becomes difficult to increase the torque. The winding voltage of each phase is given by Eq. (5). Here, when a large torque is generated, the current value is also large, and Bo refers to the saturation magnetic flux density of the soft magnetic material as shown inFIG.3(a). In the formula (5), the rotor axial length of the stator and the rotor is Ls, and the (rotor axial length)/(axial length Ls of the stator) of each part of the rotor magnetic pole is the axial length ratio Kra, and the winding voltage is proportional to Kra. Therefore, according to the formula (5), in order to make the winding voltage smaller than the power supply voltage at high speed rotation, the axial length ratio Kra must be reduced. When driving the conventional reluctance motors shown inFIGS.46and47at high speed, limiting the current to weaken the field to reduce the winding voltage to below the power supply voltage and energizing a large current at high speed rotation to output a constant power are inconsistent with respect to the current. In the conventional reluctance motor, it is possible to inject electric power at the timing in the rotation angle range where the voltage of each phase winding is lower in generating pulsating torque. This technique can also be used in combination with the configuration ofFIG.33. First,FIG.32describes an example of a control device for the reluctance motor of the present invention. A reference sign321shows an example of the reluctance motor shown inFIG.1and the like, and a reference sign322shows A phase and A/ windings which energize the A-phase current Ia in the A phase winding and the A/ phase winding. A reference sign323shows B phase and B/ phase windings which energize the B-phase current Ib in the B-phase winding and the B/ phase winding, and a reference sign324C phase and C/ phase windings which energize the C phase current Ic in the C phase winding and the C/ phase winding. A reference sign325is an encoder for detecting the position of the rotor, and a reface sign325is an interface thereof for outputting a rotation speed signal329and32A which is a rotor rotation angle position θr. A reference sign32G shows a current detector that detects the A phase current Ia. A reference sign32L shows a current detector that detects the B phase current Ib. A reference sign32Q shows a current detector that detects the C phase current Ic. A reference sign327shows a rotation speed command, a reference sign328shows an adder for calculating the rotation speed error, and the calculation result is output to the compensator32B. The compensator32B performs proportional and integral control, for example, and outputs a torque command or a current command32C, which is the output thereof, to the A phase control unit32D, the B phase control unit32H, and the C phase control unit32M. The A-phase control unit32D inputs the current command32C, the rotation speed signal329, and the rotor rotation angle position θr, inputs the A-phase current detection value, calculates using the stored information such as the control mode, the drive signal32E is output to the A-phase drive circuit32F. The B-phase control unit32H has the same function and operation, inputs a B-phase current detection value, and outputs a drive signal32to the B-phase drive circuit32K. The B-phase control unit32H has the same function and operation, inputs a C-phase current detection value, and outputs a drive signal32N to the C-phase drive circuit32P. The A-phase drive circuit32F amplifies the power and supplies the A phase current Ia to the A phase winding and the A/ phase winding of322. The B-phase drive circuit32K amplifies the power and supplies the B-phase current Ib to the B-phase winding and the B/ phase winding of323. The C phase drive circuit32P amplifies the power and supplies the C-phase current Ic to the C-phase winding and the C/ phase winding of the324. It should be noted that these control functions are often executed by software using a microprocessor. FIG.33shows an example of a reluctance motor for high-speed rotation that can be driven to a high-speed rotation speed four times the base rotation speed and can output a torque of ¼ of the maximum torque of the base rotation speed at the maximum rotation speed. The cross-sectional view is (a) ofFIG.9. It is a reluctance motor with 10 stator magnetic poles and 6 rotor magnetic poles. Note thatFIG.33is a modified configuration of the rotor magnetic pole shape shown inFIG.12. InFIG.33(a), the shape of the inner peripheral surface of the stator magnetic pole SP seen from the air gap surface between the stator and the rotor is linearly developed so that the circumferential CCW direction is the horizontal axis direction ofFIG.33. The vertical axis direction inFIG.33is the rotor axis direction. InFIG.33, a reference sign331shows the AA phase, a reference sign332shows the AA/ phase stator pole, a reference sign333shows the BA phase, a reference sign334shows the BA/ phase stator pole, a reference sign335shows the CA phase, a reference sign336shows the CA/ phase stator pole, and a reference sign337shows the DA phase, a reference sign338shows the DA/ phase stator magnetic pole, a referent sign339shows the EA phase, and a referent sign33A shows the EA/ phase stator magnetic pole. The shape of the air gap surface of the stator magnetic poles of each phase has a circumferential angular width θBs of 18° and a rotor axial length of Ls. The gap between the stator magnetic poles is also 18°. FIG.33(b)shows the shape of the outer peripheral surface of the rotor magnetic pole RP as seen from the air gap surface, and the circumferential direction of the CCW inFIG.9(a)is the horizontal axis direction ofFIG.33, that is, it is a figure developed in a straight line so as to be in the right direction of the paper surface ofFIG.33. InFIG.33, the right end of the rotor magnetic pole33J Is also the tip of the CCW of12J inFIG.9(a). The rotation angle position θr of the rotor ofFIG.33(b)is 0°. Next, the shape of the rotor magnetic pole will be described. The circumferential angular width θBr of each rotor magnetic pole inFIG.33is 36°. The rotor axial width of each rotor magnetic pole has a different shape between the front 18° width portion and the rear 18° width portion in the CCW direction. The 18° width portion of the front portion has a rotor axial length of Ls/5. The 18° portion of the rear portion has a rotor axial length of Ls, which is the same length as the rotor axial length of each stator magnetic pole SP. As will be described in detail later, the length of the front portion in the rotor axial direction is reduced to Ls/5, and the time change rate of the magnetic flux interlinking with the stator winding during high-speed rotation is reduced, and the shape is such that the induced voltage generated in the stator winding does not become an excessive value. Further, since the period of the rotor magnetic poles is 60°, the gap between the rotor magnetic poles is 24°. InFIG.33(c), the rotor position θr=0° inFIG.33(b)is rotated by 18° from the rotor position θr=0°, and θr is 18°.FIG.33(d)shows a further rotated state by 18° in the CCW direction, where the rotation position θr is 36°. The rotor position θr of the part (e) is 54°. The rotor position Θr inFIG.33(f)is 60°, and the relationship between the stator and the rotor is the same as inFIG.33(b). By rotating the rotor in this way and changing the rotor rotation angle position θr, the magnetic relative relationship between each stator pole SP and each rotor pole RP changes, so rotational torque of the rotor can be obtained by exciting each stator magnetic pole SP at an appropriate timing. Next, the relationship between the voltage acting when a current is applied to each winding of the stator magnetic pole, the motor output power, and the torque will be described. However, it is a characteristic when the electromagnetic relationship is simply modeled. Now, consider that the state in which the AA phase winding91and the AA/ phase winding92ofFIG.9(a)are connected in series, and a constant current Io [A] having a value close to the continuous rating as the AA phase current IaA is energized, then the rotor is rotated to CCW at a constant speed Vso [radian/sec]. The CCW direction ofFIG.9(a)is the right direction of the paper surface ofFIG.33. The winding voltage of the AA phase at this time is the voltage VaA inFIG.34. The horizontal axis of VaA inFIG.34is time t, and the value of the rotor rotation angle position θr at that time is shown in the lowermost stage ofFIG.34. First, the magnetic flux interlinking with the AA phase winding when the rotor rotation angle position θr approaches from 0° to 18° and the AA phase winding voltage VaA will be described. The rotor magnetic pole33J inFIG.33starts to face the AA phase stator magnetic pole331from 0° of θr via an air gap. It is the state from (b) to (c) ofFIG.33. The rotor axial length of the front portion of the rotor magnetic pole33J is ⅕ of the axial length Ls of the stator magnetic pole, and the rotational change rate of the magnetic field passing through the rotor magnetic pole and the stator magnetic pole is ⅕ of the maximum value. Here, the voltage inFIG.34is normalized, and the AA phase winding voltage VaA between 0° and 18° is shown as 0.2. Next, when θr is between 18° and 36°, it is the state from the parts (c) to (d) inFIG.33. The rear portion of the rotor magnetic pole33J faces the AA phase stator magnetic pole331. On the other hand, the front portion of the rotor magnetic pole33J goes off. The magnetic flux that passes is the deduction of them, and the winding voltage VaA during this period is (1.0-0.2)=0.8. Next, when θr is between 36° and 54°, it is the state from the parts (d) to (e) inFIG.33. The rear portion of the rotor magnetic pole33J deviates from the state of facing the AA phase stator magnetic pole331, and all disengage at θr=54° in the part (e). During this time, the magnetic flux passing through decreases with rotation. The rotational change rate of the magnetic flux passing through the rotor magnetic pole and the stator magnetic pole has a maximum negative value. As a result, the winding voltage VaA of the AA phase in which θr inFIG.34is between 36° and 54° becomes −1.0. Next, when θr is between 54° and 60°, it is the state from the parts (e) to (f) inFIG.33. During this period, the stator magnetic pole331does not face the rotor magnetic pole33J, so the magnetic flux passing through is zero. During this period, the winding voltage VaA of the AA phase becomes 0. Since the distance between the rotor magnetic poles is 60°, the part (e) is in the same state as the original part (b) where the explanation was first started. As described above, θr rotates by repeating the operation of 0° to 60°. Similarly, the BA phase voltage VbA is the voltage of the winding in which the windings93and94ofFIG.9(a)are wound in series, and the voltage VbA shown inFIG.34is a voltage whose phase is delayed by 12° with respect to the AA phase voltage VaA. Similarly, the CA phase voltage VcA is the voltage of the winding in which the windings95and96are wound in series, which is the voltage VcA ofFIG.34, which is a voltage whose phase is delayed by 24° with respect to VaA. Similarly, the DA phase voltage VdA is the voltage of the winding in which the windings97and98are wound in series, which is the voltage VdA inFIG.34, which is a voltage whose phase is delayed by 36° with respect to Va4. Similarly, the E4 phase voltage Ve4is the voltage of the winding in which the windings99and9A are wound in series, which is the voltage Ve4inFIG.34, which is a voltage whose phase is 48° behind Va4. The voltage of each of these phases has a relationship of formulas (1) to (12). The same formula applies to the D phase and the E phase. However, it Is a mathematical formula that holds under the above-mentioned various simplified conditions. Moreover, each voltage, each current, and each torque normalize their values. The AA phase voltage VaA, BA phase voltage VbA, CA phase voltage VcA, DA phase voltage VdA, and EA phase voltage VeA described with reference toFIG.34have the relationship of the formula (5). Then, in the formula (8), as the A phase torque is proportional to the A-phase voltage, The AA phase torque TaA, BA phase torque TbA, CA phase torque TcA, DA phase torque TdA, and EA phase torque TeA related to the reluctance motor ofFIG.9(a)have constant values (Io/Vso), so that each phase voltage is proportional to VaA, VbA, VcA, VdA, VeA. In that sense, each phase torque TaA, TbA, TcA, TdA, and TeA are added in parentheses under each phase voltage VaA, VbA, VcA, VdA, and VeA inFIG.34. Next, a method of generating continuous torque in the positive direction of CCW or a method of generating torque in the CW direction during rotation to CCW will be described with the reluctance motors shown inFIGS.9(a),33, and34. The specific method is generating continuous torque in the positive direction of CCW by the reluctance3omotor shown inFIG.9(a),FIG.12andFIG.13described above, or the same method of generating torque in the CW direction during rotation to CCW. In the section where TaA, which is the AA phase torque ofFIG.34, generates a positive torque, θr is 0° to 36°, 60° to 96°, and the like, and the current shown by the solid line of IaAFH inFIG.34is energized. TbA, which is the BA phase torque, energizes a current whose phase is 12° behind IaAFH. TcA, which is the CA phase torque, energizes a current whose phase is delayed by 24° from IaAFH. TdA, which is the DA phase torque, energizes a current whose phase is 36° behind IaAFH. TeA, which is the EA phase torque, energizes a current whose phase is 48° behind IaAFH. The total torque of these is 341 of TtA inFIG.34. It is a torque that repeats 1.2 and 1.8 in a cycle of 12°, and its average value is 1.5. Here, when the current shown by the broken line of IaAFH inFIG.34is applied, the torque pulsation disappears, and the torque becomes a constant value of 1.0. When the required torque of the motor is ⅔ or less of the maximum value, the energization method shown by the broken line is preferable in terms of noise and vibration. However, in high-speed rotation, the induced voltage of the winding needs to be lower than the power supply voltage, and there is a limitation of the energizing current. For example, at a rotation speed of the motor base rotation speed Nba or less, a current as shown in IaAFH inFIG.34can be applied, but when the torque increases to some extent at a rotation speed of Nba or more, the induced voltage of the winding exceeds the power supply voltage. Now, it is assumed that the maximum value of the winding induced voltage VaA of the AA phase at the base rotation speed Nba is 0.8 as shown inFIG.34, and the power supply voltage Vdc is 1.0. Then, it is assumed that the maximum rotation speed Nmax is four times higher than Nba. The simplest method of variably controlling the torque at high speed rotation is to create a rotation region in which the winding induced voltage does not exceed the power supply voltage Vdc, and control the current in the rotation region. When the current of IaAFL is applied to the AA phase winding at the maximum rotation speed Nmax, the winding induced voltage VaA of the AA phase at the base rotation speed Nba is 0.2, so the VaA at the maximum rotation speed Nmax is (0.2×(Nmax/Nba))=0.8, which is 0.2 smaller than the power supply voltage Vdc. The same is true for the other phases. Therefore, if the winding impedance is ignored and simplified, there is a margin of 0.2 in the power supply voltage at the maximum rotation speed Nmax. When a current as shown by the solid line of IaAFL inFIG.34is applied to each phase, the total torque becomes TtL. When the current shown by the broken line of IaAFL is applied, the torque becomes a constant value of 0.2, and the torque pulsation can be eliminated. Since the broken line current waveform of IaAFL has a trapezoidal shape, it is easy to increase or decrease the current, which is convenient. In the section where the AA phase current IaAFL is energized, as described above, the winding induced voltage VaA of the AA phase is 0.8 even at the maximum rotation speed Nmax, so the power supply voltage Vdc has a margin of 0.2, and the AA phase current IaAFL can be increased. The motor output power at this time is 0.8 because the torque is 0.2 but the rotation speed is four times the base rotation speed Nba. Furthermore, the power can be increased by increasing the current of each phase. In this way, a large amount of power can be output in the vicinity of the maximum rotation speed Nmax. It is also possible to output a torque larger than the torque indicated by the TTL at the rotation speed between the base rotation speed Nba and the maximum rotation speed Nmax without increasing the current value. It is a method of energizing a current such as between IaAFL and IaAFH. In the section where the winding voltage exceeds the power supply voltage Vdc, the energizing current is regenerated to the power supply, but since a part of the magnetic energy at that time becomes torque, it can be used as torque output. However, in this case, torque pulsation is unavoidable. Next, a method of generating torque in the CW direction in a state of rotating at a speed Vso in the CCW direction with the reluctance motors ofFIGS.9(a),33, and34will be described with reference toFIG.13. It is also an operation that brakes the motor and regenerates it. In the section where TaA, which is the AA phase torque inFIG.34, generates a negative torque, θr is 36° to 54°, 96° to 114°, and the like, and the AA phase current IaA shown by the solid line of IaAR inFIG.34is energized. Similarly, the BA phase current IbA energizes a current whose solid phase of IaAR is delayed by 12°. Similarly, the CA phase current IcA energizes a current whose solid phase of IaAR is delayed by 24°. Similarly, the DA phase current IdA carries a current whose solid phase of IaAR is delayed by 36°. Similarly, the EA phase current IeA energizes a current whose solid phase of IaAR Is delayed by 48°. The total torque of each phase is 342 of TtA inFIG.34. It is a torque that repeats −1.0 and −2.0 in a cycle of 12°, and its average value is −1.5. Here, when the current shown by the broken line of IaAR inFIG.34is applied, the torque pulsation disappears, and the torque becomes a constant value of −1.0. The energization method shown by the broken line is preferable in terms of noise and vibration. As described above, an example in which the maximum rotation speed Nmax is four times the base rotation speed Nba is shown inFIGS.33and34. When the maximum rotation speed Nmax is larger than the base rotation speed Nba, low torque ripple can be achieved, and low noise and low vibration can be realized by devising the shape of the rotor magnetic pole and the control method. Then, the torque can be freely controlled at high speed rotation. Further, the ratio of the base rotation speed Nba to the maximum rotation speed Nmax has the following relationship with the rotor axial length ratio Kra, which is the width of the front portion of the rotor magnetic pole inFIG.33. Kra=Nba/(Nba+Nmax) (25) For example, when this rotation speed ratio is 2, Kra=⅓, and the width of the front portion of the rotor magnetic pole in the rotor axial direction is Ls/3. The width of the rear part in the rotor axis direction is Ls. As a method for putting the front portion of the rotor magnetic pole into practical use, the magnetic characteristics can be realized by various methods as shown inFIG.17, and these are also included in the present invention. Further, the shape of the rotor magnetic pole shown inFIG.33can be deformed and improved according to the required characteristics and applications. Nineteenth Embodiment Next, an embodiment of claim12will be shown and described with reference toFIG.35. The present invention is intended for motors for applications such as motors for main engines for electric vehicles, which mainly rotate in one direction, with the CCW rotation assigned to the forward rotation direction, the motor shape and configuration that prioritize performance in the forward rotation direction will reduce noise and vibration, improve torque characteristics, and so on. However, if the shape of the rotor magnetic pole is devised to improve the torque generation range in the forward rotation direction, on the other hand, new problems such as torque pulsation in the CW direction are likely to occur. Claim12is a reluctance motor that improves this torque pulsation in the reverse rotation direction. FIG.35is a diagram showing the voltage, current, and torque of each phase when the reluctance motor ofFIG.8(a),FIG.10andFIG.11shown above is rotated to CCW to generate torque of CW. A reference sign Va3R ofFIG.35shows a diagram in which only the negative voltage portion of Va3ofFIG.11is taken out. A reference sign Vb3R ofFIG.35shows a diagram in which only the negative voltage portion of Vb3ofFIG.11is taken out.FIG.35shows a diagram in which only the negative voltage portion of Vc3inFIG.11is taken out. At the time of these voltage characteristics, when the current shown by the solid line of Ia3R inFIG.11is applied as the current of the A3 phase and the currents of the other phases are also applied with the same currents of the respective phases, the motor torque is112in Tt3ofFIG.11, and −1.0 and −2.0 are pulsating torques that repeat every 15° cycle. Therefore, problems of torque ripple, noise, and vibration occur. The voltage of each phase is expressed by the formula (5), and the torque is expressed by the formula (8). One method of reducing the pulsation of the torque of112is to change the current value of each phase according to the formula (8). Since the absolute torque value is large in the portion of each phase voltage ofFIG.35where the voltages of the two phases overlap, the current of the two phases may be halved in the section where the voltages overlap. Since Va3R and Vb3R overlap while θr is between 33.75° and 41.25° inFIG.35, during this period, the torque can be halved by linearly increasing the A3 phase current Ia3R and linearly decreasing Ib3R. Similarly, when drawing the other parts in the same manner for the other phases, the A3 phase current Ia3R, the B3 phase current Ib3R, the C3 phase current Ic3R, and the D3 phase current Id3R are obtained inFIG.35. The torque of the entire motor at this time is −1.0 of Tt3rginFIG.35, and the torque pulsation can be reduced. In this way, for the part where the torque generation of each phase overlaps, the exciting current of the stator magnetic pole that is preceded by the regenerative torque in time is gradually reduced, and at the same time, it is possible to gradually increase the exciting current of the stator magnetic pole that follows in time so that the pulsation of the regenerative torque of the entire motor becomes small. Further, since the waveform of each phase current inFIG.35is trapezoidal, it is easy to increase or decrease each phase current, and it is possible to reduce vibration and noise due to a sudden change in the attractive force between the stator magnetic pole and the rotor magnetic pole. Further, the trapezoidalization of each phase current waveform inFIG.35is an example in which the broken line of the regenerative current IaAR inFIG.34described above also reduces the pulsation of the regenerative torque. The same applies to the dashed line of IaAFL and the trapezoidal current of the broken line of IaAFH, which are the power running currents inFIG.34, and the torque pulsation can be reduced. It should be noted that the above description is a story under various simplified conditions and is a mathematical formula. In addition, each voltage, each current, and each torque are shown in a normalized manner. In particular, the assumption that the torque of each phase inFIG.35is proportional to the current of each phase shown is not accurate because it ignores the exciting current component. However, it can be easily corrected by adding an exciting current component to each phase current. Twentieth Embodiment Next, claim13will be described. Although the rotor magnetic pole shape and its characteristics have been described in many of the above figures and their explanations, the electromagnetic action between the stator magnetic pole and the rotor magnetic pole is relative, and the stator magnetic pole ban be deformed into various shapes. They are equivalent to those described as the shape of the rotor magnetic poles in the present invention and are included in the present invention. For example, specifically, in order to facilitate the winding of the winding of the stator magnetic pole, a part of the four corners of the stator magnetic pole is deleted and deformed, and the deformed portion is compensated by the rotor shape. Further, the permanent magnet can be arranged and fixed in the vicinity of the tip of the tooth of the stator constituting the stator magnetic pole, and at the same time, the shape of the tooth tip can be deformed. Further, the deformed portion can be made into a shape that is supplemented by the rotor shape. In such a case, the rotor magnetic pole shape shown in the present invention may be realized on the stator magnetic pole side, the surface shape of the rotor magnetic pole may be rectangular, and the rotor magnetic pole shape and the stator magnetic pole shape may be reversed. Twenty-First Embodiment Next, an embodiment of claim14will be shown and described with reference toFIGS.37,40, and42. First, the configuration of the full-pitch winding ofFIG.20will be described, and the phase currents Iab, Ibc, and Ica are shown by the formulas (13), (14), and (15), and the relationship with the currents Ia7, Ib7, and Ic7of the concentrated winding around each stator magnetic pole is shown. Then, it was shown that the copper loss of the full-pitch winding inFIG.20can be made smaller than the copper loss of the concentrated winding. However, the voltages Vw1and Vw2of the full-pitch winding windings W1and W2for exciting one set and two stators shown inFIG.21are shown by the formulas (16) and (17), and as a result of the voltage shown in formula (18) acting differentially on formulas (16) and (17), it is shown as an example of a generalized motor model that the voltages Vw1and Vw2become excessive voltages due to voltage bias. As a specific example of increasing the size of the drive circuit, an example of exciting the reluctance motor ofFIG.20using the three-phase reluctance motor drive circuit ofFIG.36will be shown. First, in the drive circuit ofFIG.36, there is a control circuit36A for all of the drive circuits. A reference sign36B shows the DC voltage source, reference signs361,362,363,364,365,366show the drive transistors, and a reference sign367shows the AB phase full-pitch winding windings207and208inFIG.20, which energize the AB phase current lab. Also, a reference sign368show the BC phase full-pitch windings209and20A inFIG.20, which energize the BC phase current Ibc, and a reference sign369shows the CA phase full-pitch winding windings of20B and20C inFIG.20, which energizes the CA phase current Ica. The remaining 6 diodes are power regeneration diodes. Now, when energizing ab and Ica to excite the A7 phase stator pole201and the A7/ phase stator pole202, excessive voltages represented by the formulas (16) and (17) are generated in the AB phase full-pitch winding winding367and the CA phase full-pitch winding winding369inFIG.36. In order to keep the winding voltage below the voltage of the DC voltage source36B, for example, if the number of windings is halved, the winding voltage is halved but the winding current is doubled. Therefore, it is necessary to double the current capacity of the transistors361,362,363,364,365,366ofFIG.36, which causes problems of large size and high cost. Next, the drive circuit ofFIG.37and its operation for reducing the problems of the formulas (16), (17), and (18), that is, the problem of increasing the cost and the size of the drive circuit will be described. The reluctance motor to be driven is the reluctance motor ofFIG.22, which is a multi-pole pair ofFIG.20. First, in order to clarify the voltage and current of the two-pole pair reluctance motor ofFIG.22, the voltage and current ofFIG.20which is a one-pole pair of reluctance motor will be described. The currents lab, Ibc, and Ica of the full-pitch winding inFIG.20are indicated by the currents Ia, Ib, and Ic of the concentrated winding wound around each stator magnetic pole according to the formulas (13), (14), and (15). Further, inFIG.20, as shown in the figure, the A7 phase magnetic flux is φa, the B7 phase magnetic flux is φb, and the C7 phase magnetic flux is φc because of its symmetry. The voltages Vb and Vc in the case of the concentrated winding around each stator magnetic pole inFIG.1are expressed by the following formulas based on the relationship between the interlinkage magnetic fluxes φa, φb and φc, as in the formula (4) and Va. Va=Nwa×dφa/dt Vb=Nwa×dφb/dt(26) Vc=Nwa×dφc/dt(27) As the same as those inFIG.21and (16) and (17), the voltage Vab of the AB phase winding20D, the voltage Vbc of the BC phase winding20E, and the voltage Vca of the CA phase winding20F are represented by the following formulas in relation to the interlinkage magnetic flux of each winding inFIG.20. Vab=Nwx×d(φa+φb-φc)/dt(28)=Va+Vb-Vc(29)Vbc=Nwx×d(-φa+φb+φc)/dt(30)=-Va+Vb+Vc(31)Vca=Nwx×d(φa-φb+φc)/dt(32)=Va-Vb+Vc(33) Here, formulas (29), (31), and (33) are not only complicated but also have a large peak voltage because a differential voltage is applied by the voltage component of formula (18). Therefore, in the drive circuit ofFIG.37, which will be described later, two windings are connected in series to cancel the component of the differential voltage of the formula (18), simplify the energization. That is, the two voltages of the formulas (29), (31), and (33) are connected in series, the components of the differential voltage of the formula (18) are canceled, and the voltage is simplified and energized as in the following formula. Vab+Vca=2×Va(34) Vca+Vbc=2×Vc(35) Vbc+Vab=2×Vb(36) As a result, an excessive voltage is not generated at both ends of the two windings connected in series, that is, the problem of voltage bias is eliminated, and the voltage burden on the drive circuit can be eliminated. Since it is not necessary to reduce the number of windings of the winding, the current of the winding does not increase and it is not necessary to increase the current capacity of the transistor. In addition, the whole section winding shown inFIGS.20,21, and22, and the method of using the toroidal winding in which the winding of each slot shown inFIGS.23,24, and25is wound to the rear side of the back yoke has its own features, but there are problems of complicated and excessive voltage. To solve these problems, in the method of connecting the drive circuit ofFIG.37and each winding shown later, energization of the combined currents of formulas (13), (14), and (15) to each winding, and the complicated and excessive voltage of each winding as in the formulas (29), (31) and (33) is converted into a simplified voltage as in the formulas (34), (35) and (36) and driven. The complicated relationship between the current and the voltage of each winding is solved, and the above-mentioned problem is solved. Since the relationship between the current, interlinkage magnetic flux, voltage, torque, and power of the full-pitch winding is complicated, it becomes easier to understand the excitation method and control method by converting the current, interlinkage magnetic flux, voltage, torque, and power of the concentrated winding wound around each stator pole with the above formula. If a simple model is made by ignoring the winding resistance, the sum of products of the phase currents Ia, Ib, and Ic of the concentrated winding and the phase voltages Va, Vb, and Vc becomes the power [W], so that dividing the power by the rotation speed [rad/sec] gives the torque [Nm]. Next, as a specific motor, The case where the rotor magnetic poles ofFIGS.20and22have the configurations and characteristics described with reference toFIGS.6and7is described by showing the current and voltage of the full-pitch winding inFIG.38. Further, as described above, the cross-sectional view ofFIG.20shows a configuration in which the concentrated winding of each stator magnetic pole shown inFIG.1is converted into a full-pitch winding.FIG.38is a characteristic added toFIG.7in accordance with each phase voltage and current Ia2F ofFIG.7. The horizontal axis of each current and each voltage inFIG.38is time t, and shows a state of rotation at a constant speed Vso. Then, the rotor rotation angle position θr at that time is indicated by the electric angle angle in the bottom column. A reference sign Ia7inFIG.38shows an A7 phase current Ia7that energizes the concentrated winding windings17,18and1C and1D wound around the A7 phase stator magnetic poles11and12inFIG.1, and the voltage across the two windings connected in series is Va7inFIG.38. A reference sign Ib7inFIG.38shows a B7 phase current Ib7that energizes the concentrated winding windings1U,1V,1S, and1T wound around the B7 phase stator magnetic poles13and14inFIG.1, and the voltage across the two windings connected in series is Vb7inFIG.38. A reference sign Ic7inFIG.38shows an A7 phase current Ic7that energizes the concentrated winding windings1Q,1R,1P, and1N wound around the C7 phase stator magnetic poles15and16inFIG.1, the voltage across the two windings connected in series is Vc7inFIG.38. Iab, Ibc, and Ica inFIG.38are currents represented by the formulas (13), (14), and (15). FIG.1of the centralized winding,FIG.20of the full-pitch winding, and an example of their voltage and current are shown inFIG.38. However, in the drive circuit ofFIG.37described later, two full-pitch windings of each phase are required, for a total of six full-pitch windings, so the motor ofFIG.22in which the one-pole pair ofFIG.20is a two-pole pair will be described.FIGS.20and22are functionally equivalent to each other. Reference signs22A and22D inFIG.22show A7 phase stator magnetic poles, and reference signs22A/ and22D/ show A7/ phase stator magnetic poles. Reference signs22B and22E show B7 phase stator magnetic poles, and Reference signs22B/ and22D/ show B7/ phase stator magnetic poles. Reference signs22C and22F show C7 phase stator magnetic poles, and reference signs22C/ and22F/ show C7/ phase stator magnetic poles. A reference signs221shows coil end portions of the AB phase full-pitch winding, so that the AB phase current Iab1represented by the formula (13) is energized. A reference signs224also shows coil end portions of the AB phase full-pitch winding which also energizes the AB phase current Iab2. The currents Iab1and Iab2have the same current command in the control device, but they are physically separated due to the convenience of the drive circuit shown inFIG.37. Similarly, reference sings222and225show coil end portions of the BC-phase full-pitch windings, and carry BC-phase currents Ibc1and Ibc2, respectively. Similarly, reference sings223and226show coil end portions of the CA phase full-pitch winding, and energize the CA phase currents Ica1and Ica2, respectively. Next, an example will be described in which the reluctance motor ofFIG.22is driven by the drive circuit ofFIG.37to reduce the problem of increasing the size of the drive circuit. If the drive circuit ofFIG.37is connected in series with the full-pitch windings adjacent to each other in the circumferential direction ofFIG.22, the voltage across the drive circuit can remove the differential voltage shown in Eq. (18), so that it utilizes the fact that it can be simplified as in equations (34), (35), and (36). Further, the six transistors shown inFIG.37can energize two sets of current paths to improve utilization efficiency. The configuration is such that mutual interference between the voltage and the current in the two sets of current paths in the drive circuit is reduced. A reference symbol37S inFIG.37shows a control circuit for the entire drive circuit, a reference symbol37R shows a DC voltage source, and reference symbols371,372,373,374,375, and376show drive transistors. For each winding and energizing current, InFIG.377, the AB phase current Iab1is energized by the transistor371in the AB phase full-pitch winding221ofFIG.22, and In37A ofFIG.37, the AB phase current Iab2is energized by the transistor374in the AB phase full-pitch winding224ofFIG.22. Similarly, in379, the BC so phase current Ibc1is energized by the transistor373in the BC phase full-pitch winding222, and the BC phase current Ibc1is energized by the transistor373, and in37C, the BC phase current Ibc2is energized by the transistor376in the BC phase full-pitch winding225. In37B, the CA phase current Ica1is energized by the transistor375in the CA phase full-pitch winding223, and in378, the CA phase current Ica2is energized by the transistor372in the CA phase full-pitch winding226. Here, as for the arrangement method of each winding inFIG.22, as shown in the figure, a method with less overlap on the winding of the coil end portion is selected, and the name of the winding and the name of the current are defined. However, considering, for example, the AB phase, there are four slots, and the coil end portion can be connected in two ways. For example, inFIG.22, since the slot of the first pole pair is connected to the slot of the opposite phase of the second pole pair, it can be said that the winding connection is different from that ofFIG.20of the one pole pair. It is also possible to reverse the two AB phase full-pitch windings on the circuit ofFIG.37. Also, those changes can be made in each phase. Therefore, although functionally equivalent, many different combinations of winding forms can be realized. For example, inFIG.37, the circuit arrangement of the windings377and37A that carry the in-phase currents Iab1and Iab2may be exchanged. Similarly,378and37B may be exchanged, and379and37C may be exchanged. The present invention includes these functionally equivalent modifications. Further, the AB phase currents Iab1and Iab2are currents that physically flow to different places, but the current command values that are controlledly targeted are the same. The same applies to the BC phase currents Ibc1and Ibc2and the CA phase currents Ica1and Ica2. A diode37Q oriented in the current direction is arranged between the AB phase full-pitch winding377and the BC phase full-pitch winding37C inFIG.37, and a diode37K oriented in the current direction is arranged between the AB phase full-pitch winding377and the CA phase full-pitch winding378. A diode37L oriented in the current direction Is arranged between the BC-phase full-pitch winding379and the CA-phase full-pitch winding378, and a diode37M oriented in the current direction is arranged between the BC-phase full-pitch winding379and the AB-phase full-pitch winding37A. A diode37N oriented in the current direction is arranged between the CA-phase full-pitch winding37B and the AB-phase full-pitch winding37A, and a diode37P oriented in the current direction is arranged between the CA-phase full-pitch winding37B and the BC-phase full-pitch winding37C. The currents flowing through each winding and each diode have the relationship of equations (13), (14), and (15). The remaining six diodes37D,37E,37F,37G,37H and37J are power regeneration diodes for the DC voltage source37R. Next, the voltage of each winding ofFIG.37will be described. The voltage between the AB-phase full-pitch winding377, the diode37K, and the CA-phase full-pitch winding378has the relationship of equation (34), and the voltage across these is (2×Va). Similarly, the voltage between the BC-phase full-pitch winding379, the diode37L, and the CA-phase full-pitch winding378has the relationship of equation (35), and the voltage across these is (2×Vc). The voltage between the BC-phase full-pitch winding379, the diode37M, and the AB-phase full-pitch winding37A has the relationship of equation (36), and the voltage across these is (2×Vb). The voltage between the CA-phase full-pitch winding37B, the diode37N, and the AB-phase full-pitch winding37A has the relationship of equation (34), and the voltage across these is (2×Va). The voltage between the CA-phase full-pitch winding37B, the diode37P, and the BC-phase full-pitch winding37C has the relationship of equation (35), and the voltage across these is (2×Vc). The voltage between the AB phase full-pitch winding377, the diode37Q, and the BC phase full-pitch winding37C has the relationship of equation (36), and the voltage across these is (2×Vb). These voltages across the equations (34), (35) and (36) are relatively simple voltage waveform as compared to the individual voltages of the windings represented by the equations (29), (31) and (33). Next, an example of a specific waveform of each current applied to each winding ofFIG.37and each applied voltage is shown. Previously, as an example of a reluctance motor in which a centralized winding is applied to each stator magnetic pole, an example of a cross-sectional view ofFIG.1, a rotor magnetic pole shape ofFIG.6, and each voltage, current, and torque ofFIG.7is shown.FIG.20is a cross-sectional view of a reluctance motor obtained by converting the concentrated winding ofFIG.1into a full-pitch winding. Each phase current and each phase voltage ofFIGS.1and6and each phase current ofFIG.20are shown inFIG.38.FIG.22is a cross-sectional view of a reluctance motor obtained by convertingFIG.20of a 1-pole pair into a 2-pole pair, and theoretically, both motors are electrically equivalent. Therefore,FIG.38is an example of the current and voltage of the two-pole pair reluctance motor ofFIG.22, and also shows the specific waveforms of each circuit ofFIG.37, each current energizing each winding, and each voltage to be applied. It should be noted that Va7, Vb7, and Vc7inFIG.38are the same variables as Va, Vb, and Vc in the equations (29), (31), (33), (34), (35), and (36). Further, in the actual current control, PWM control is usually performed on each transistor to obtain an arbitrary equivalent average voltage and current, so that there is a slight difference in a strict sense. Further, in order to perform precise current control by PWM control, although the description is omitted inFIG.37, a current detecting means for detecting the current value of each phase and feedback control using the current detection signal are required. It is also necessary to detect the rotor rotation angle position by the encoder325ofFIG.32. As the operation ofFIG.37, lab, Ibc, and Ica ofFIG.38are energized to each full-pitch winding, and the torque71of Tt2ofFIG.7can be obtained. Luk71is a constant value, and the torque value thereof is a value represented by equations (1) to (12) depending on each shape and current value of the reluctance motor. However, it is a mathematical formula that holds under various simplified conditions. This is the simplification condition described above. Next, the utilization efficiency of the drive circuit ofFIG.37will be described. One of the advantages of the reluctance motor with full-pitch winding as shown inFIGS.20and22is the miniaturization of the drive circuit. When the three full-pitch windings ofFIG.20are driven by the conventional drive circuit ofFIG.36, the A7 phase stator magnetic pole201and the A7/ phase stator magnetic pole202are driven by energizing the AB phase full-pitch winding windings of windings207and208and the CA full-pitch winding windings of windings20B and20C. Since the maximum output Pfmax of the conventional drive circuit ofFIG.36under this condition is two windings in three phases, the power to be supplied may be as follows. Pfmax=Vdc×Irat×2 (37) Here, Vdc is the power supply voltage and Irat Is the current capacity of the transistor. On the other hand,11inFIG.1is an A1 phase stator magnetic pole, and drives the centralized winding windings17,18and1C,1D by energizing the A phase current Ia. Since the maximum output Pcmax of the conventional drive circuit ofFIG.36under this condition is one winding in three phases, the following equation is obtained. Pcmax=Vdc×Irat (38) The maximum output Pfmax of the equation (37) is twice the maximum output Pcmax of the equation (38). However, in the conventional drive circuit ofFIG.36, the winding voltage has characteristics as shown in equations (16), (17), and (18), the voltage becomes complicated, and there was a problem that an excessive voltage is generated when a heavy load of high-speed rotation occurs. Next, the utilization efficiency when driving by the drive circuit of the present invention ofFIG.37and the reluctance motor of the full-pitch winding ofFIG.22will be described. Similar to the example ofFIG.20, A7 phase stator magnetic poles22A,22D and A7/ phase stator magnetic poles22A/,22D/ inFIG.22are AB phase full-pitch winding windings221(377),224(37A) and CA phase full-pitch winding windings223(37B),226(378) are energized and driven. Since the maximum output Pnmax of the drive circuit of the present invention inFIG.37under this condition is two windings in three phases, there is a possibility that the following equation can be obtained. Pnmax=Vdc×Irat×2 (39) At this time, on the drive circuit ofFIG.37, the current Irat is applied to the windings377and378, and the current Irat is applied to the windings37B and37A. As explained earlier, since the sum of the voltages of the two windings connected in series cancels out the voltage components of (18) as shown in equations (34), (35), and (36), the excessive voltage under heavy load of high-speed rotation is reduced inFIG.37. Although it is a drive circuit of 6 transistors, power is supplied by 2 sets of paths. The maximum output Pnmax of the drive circuit of the present invention is twice the maximum output Pcmax of the conventional drive circuit. The number of full-pitch winding windings inFIG.22which are paired with two poles is 6, and the number of full-pitch winding windings inFIG.20is 3, which is twice that number. Then, in the drive circuit of the present invention ofFIG.37, two windings are connected in series and energized. Therefore, the number of windings of each full-pitch winding inFIG.22is set to ½ of the number of windings of full-pitch winding windings inFIG.20, and the number of windings of both motors and the winding thickness are determined to be balanced. The current values of each phase of both motors are the same. As described above, by driving the reluctance motor of the full-pitch winding ofFIG.22with the drive circuit ofFIG.37, copper loss of each winding can be reduced, motor efficiency can be improved, and miniaturization and cost reduction can be realized. At the same time, the problem of excessive voltage and voltage complication, indicated by the equations (16), (17), (18), (29), (31), and (33), was solved by making the relationship of the equations (34), (35), and (36). The first point of the reluctance motor that can be driven by the drive circuit ofFIG.37is that the salient pole type stator magnetic pole and the salient pole type rotor magnetic pole are used, so that each magnetic pole is separated from the adjacent magnetic pole in the circumferential direction as shown in each figure. The second point is that the windings arranged in the slots can excite the stator magnetic poles on both sides of the winding in the circumferential direction. That is, the winding can be shared. It is the relationship of the equations (13), (14), and (15). For example, a motor with a full-pitch winding shown inFIGS.20,21,22and a toroidal winding that winds the winding of each slot shown inFIGS.23,24, and25to the rear side of the back yoke. On the contrary, the reluctance motors ofFIGS.46and1have a dedicated centralized winding wound around each stator magnetic pole and cannot be shared, so that they cannot be driven by the drive circuit ofFIG.37. The third point is that two windings can be connected in series so that the voltage components of Eq. (18) can be offset. On the other hand, the first main point of the configuration of the drive circuit ofFIG.37is that, as described above, the two windings corresponding to the relations of the equations (34), (35) and (36) are connected in series and to each other so that the voltage components of the equation (18) cancel each other out. The second point is that the currents of the two paths of the currents related to the equations (13), (14), and (15) can be energized at the same time. Furthermore, all the currents related to the equations (13), (14) and (15) can be energized at the same time. The winding arrangement order in the drive circuit example ofFIG.37is the arrangement order of the equations (13), (14), and (15). Further, since the winding arrangement order in the drive circuit ofFIG.37is equivalent even if the windings of the same phase are arranged in reverse, the arrangement on the paper surface can be rewritten and converted as the winding arrangement order ofFIG.22. As a result, the drive circuit ofFIG.37is configured to effectively drive the winding configuration and the drive circuit by closely integrating the winding configuration and the drive circuit by utilizing the theoretical relationship between the voltage and current of the winding ofFIG.22. As a result, the drive circuit of the present invention shown inFIG.37can efficiently supply electric power, and has a characteristic that may output twice as much electric power as the conventional drive circuit. The utilization efficiency of the drive circuit of the present invention is twice that of the conventional one, and there is a possibility that the drive circuit can be reduced in size and cost by half. It should be noted that the degree to which the motor can be miniaturized and the drive circuit can be miniaturized depends on the characteristics of the motor, so noise reduction, torque ripple reduction, maximum torque, etc. will be optimized according to the motor application. Later, an example of a motor shape advantageous for miniaturization of the drive circuit of the present invention inFIG.37and an example of a reluctance motor utilizing a permanent magnet will be described. Further, the37Q,37K,37L,37M,37N, and37P diodes that block the reverse current are not all necessary in motor applications where there are few sudden changes in current and voltage. The drive circuit of a permanent magnet application synchronous motor with three-phase AC, sine wave voltage, and sine wave current, which is often used as a mainstream motor, controls voltage and current by PWM control with six transistors. Then, the maximum output Psmax is the same as the equation (38), and becomes the following equation. Psmax=Vdc×Irat Therefore, the method of connecting the drive circuit of the present Invention and each winding of the full-pitch reluctance motor shown inFIG.37may be halved in size and cost as compared with the drive circuit of the current permanent magnet application synchronous motor. In addition, the brush-equipped DC motor can control the forward and reverse current and torque with four transistors, but the drive circuit of the present invention and the reluctance motor of the full-pitch winding ofFIG.37have a possibility of outputting power in two paths with six transistors. Therefore, the output is relatively (⅔)/(½)=1.33 times. This means that the drive circuit of the present invention inFIG.37can be downsized to ¾ of the drive circuit of the brushed DC motor. It is important to reduce the cost, size, and weight of the motor and its drive circuit in applications such as the main engine of electric vehicles. Twenty-Second Embodiment Next, another embodiment of claim14is shown. When the motor ofFIG.20is applied to the drive circuit of the present invention ofFIG.37, the one-pole pair motor ofFIG.20has only three full-pitch windings, so it is necessary to convert to a total of six windings. Specifically, each winding is divided into two parallel windings and arranged in the same slot. The AB phase full-pitch winding Wab of the windings207and208is divided into two parallel windings Wab1and Wab2. The BC phase full-pitch winding Wbc of windings209and20A is divided into two parallel windings Wbc1and Wbc2. The CA-phase full-pitch winding Wca of the windings20B and20C is divided into two parallel windings Wca1and Wca2. The AB phase full-pitch winding377of the drive circuit of the present invention inFIG.37is referred to as winding Wave1, and the winding37A is referred to as winding Wave2. The BC phase full-pitch winding379is referred to as winding Wbc1, and the winding37C is referred to as winding Wbc2. The CA phase full-pitch winding37B Is referred to as winding Wca1, and the winding378is referred to as winding Wca2. With such a winding configuration and winding connection, it can be driven in the same manner as inFIG.22. In order to arrange the drive circuit inFIG.37at each position, it is necessary to insulate the two in-phase windings arranged in the same slot from each other. Twenty-Third Embodiment Next, as another embodiment of claim14, a case where the motor ofFIG.23is applied to the drive circuit of the present invention ofFIG.37will be described. As described above, there are six windings inFIG.23, and the winding on the opposite side of 180° on the paper surface ofFIG.23is a winding that carries a current of the same phase. The AB phase winding377of the drive circuit of the present invention ofFIG.37is the winding237ofFIG.23, and the winding37A is the winding238. The BC phase winding379is the winding239, and the winding37C is the winding23A. The CA phase winding37B is referred to as winding23B, and the winding378is referred to as winding23C. With such a winding configuration and winding connection, it can be driven in the same manner as in the case ofFIG.22. Since the reluctance motor ofFIG.23is point-symmetric with respect to the center of the motor, the interlinkage magnetic fluxes of the AB phase windings237and238have the same magnitude, and each has a voltage of ½ of the equation (29). Similarly, the voltage of the BC phase windings239and23A is halved of that of the equation (30), respectively. The CA phase windings23B and23C each have a voltage of ½ of that of the equation (31). Twenty-Fourth Embodiment Next, as another embodiment of claim14, a case where the motor ofFIG.25is applied to the drive circuit of the present invention ofFIG.37will be described. The motor ofFIG.25has a dual motor configuration in which two motors are incorporated. Compared with the configuration ofFIG.23, the one-pole pair is converted into a two-pole pair, and the winding portion on the outer diameter side ofFIG.23is utilized as the winding of the motor on the outer diameter side. Since there are four windings in the same phase and the opposite phase and three phases, the total number of windings is 12. There is a degree of freedom in placement in the drive circuit of the present invention inFIG.37, and an example of placement is shown. The AB phase winding377of the drive circuit of the present invention ofFIG.37is arranged by connecting the AB phase winding257ofFIG.25and the AB/ phase winding258in series. Similarly, the AB phase winding37A is arranged by connecting the AB phase winding257and the AB/ phase winding258ofFIG.25in series. The BC phase winding379is arranged by connecting the BC phase winding259ofFIG.25and the BC/ phase winding25A In series. The BC phase winding37C is arranged by connecting the BC phase winding25L and the BC/ phase winding25M ofFIG.25in series. The CA phase winding37B is arranged by connecting the CA phase winding25B and the CA/ phase winding25C ofFIG.25in series. The CA phase winding378is arranged by connecting the CA phase winding25N ofFIG.25and the BC/ phase winding25P in series. With such a winding configuration and winding connection, it can be driven in the same manner as in the case ofFIG.22. There is some confusion in the name and expression of the winding. For example, the AB/ phase winding258has the winding direction of the AB phase winding257reversed, and the AB/ phase winding can be said to be an AB phase winding wound in the opposite direction. When the current control of all phases of the motor is performed in a well-balanced manner, the interlinkage magnetic flux of the AB phase winding becomes the same as the Interlinkage magnetic flux of the AB/ phase winding wound in another place. Twenty-Fifth Embodiment Next, an example of driving the reluctance motor RMCON, which is a modification of the conventional reluctance motor ofFIG.46, will be described with the drive circuit of the present invention ofFIG.37. The reluctance motor ofFIG.46includes six stator magnetic poles, a centralized winding wound around each, and four rotor magnetic poles, and as can be seen from the characteristics ofFIG.47, the stator magnetic pole has a circumferential width of 30° and the rotor magnetic pole has a circumferential width of 30°. The reluctance motor RMCON converts the stator magnetic pole ofFIG.46into a pair of two poles, and winds each winding with full pitches to form the stator magnetic pole ofFIG.22. The rotor converts the rotor magnetic poles ofFIG.46into a pair of two poles, and has eight rotor magnetic poles, the circumferential width of which is 30° in electrical angle. An example of driving the reluctance motor RMCON by the drive circuit of the present invention ofFIG.37is shown inFIG.39. The shape and magnetic characteristics of the rotor magnetic poles are different from those of the reluctance motor having the characteristics ofFIG.38described above as the rotor magnetic pole configuration ofFIG.6in the stator configuration ofFIG.22. The relationship of the winding connection of the reluctance motor RMCON inFIG.37is the same as in the case ofFIG.38. The horizontal axis of each current and each voltage inFIG.39is time t, and shows a state of rotation at a constant speed Vso. Then, the rotor rotation angle position θr at that time is indicated by the angle of the electric angle in the bottom column. Further, as the magnetic characteristics of the reluctance motor RMCON, the equations (13) to (36) and (39) are satisfied. Currents Ia, Ib, and Ic inFIG.39correspond to the currents of the items on the right side of the equations (13), (14), and (15). The A-phase current Ia ofFIG.39of the reluctance motor RMCON is energized while the rotor angle θr of the electric angle is between 0° and 30° in the simple model ofFIGS.46and47, but in an actual motor, the leakage flux is generated in the vicinity of the stator magnetic pole and the rotor magnetic pole, and the reverse torque, that is, the CW torque is generated between 30° and 60° of θr. In Ia ofFIG.39, θr increases from 0 to 1.0 between −7.5° and 0° and decreases from 1.0 to 0 between 22.5° and 30°. Then, θr increases from 0 to 1.0 between 82.5° and 90° and decreases from 1.0 to 0 between 112.5° and 180°. Similarly, the B-phase current Ib has a current waveform whose phase is 60° behind that of the A-phase current Ia. The C-phase current Ic has a current waveform whose phase is 120° behind the A-phase current Ia. Since the AB phase current lab of the AB phase full-pitch winding ofFIG.39indicating the reluctance motor RMCON has the relationship of the equation (13), it has the current waveform shown in the figure. Similarly, since the BC phase current Ibc and the CA phase current Ica have the relationship of the equations (14) and (15), the current waveform shown in the figure is obtained. The A-phase voltage Va ofFIG.39indicating the reluctance motor RMCON is obtained by the magnetic flux corresponding to the A-phase magnetic flux20G ofFIG.20excited by the A-phase current Ia and the equation (4). The leakage flux between θr of −7.5° and 0° is small, and the A-phase voltage Va is also small. When θr is between 0° and 22.5°, since the area of the A phase stator magnetic pole and the rotor magnetic pole increases with the rotation of the rotor, the A-phase magnetic flux φa also increases, and the A-phase voltage Va becomes a constant value of 1.0. When θr is between 22.5° and 30°, the A-phase magnetic flux φa decreases sharply and torque Is also generated, but magnetic energy is regenerated to the power supply. Similarly, the B-phase voltage Vb is obtained by the magnetic flux (26) corresponding to the B-phase magnetic flux20H ofFIG.20excited by the B-phase current Ib. The C-phase voltage Vc Is obtained by the magnetic flux corresponding to the C-phase magnetic flux20HJ ofFIG.20excited by the C-phase current Ic and the equation (27). The voltages Vab, Vbc, and Vca of full-pitch windings of each phase and the Va, Vb, and Vc have the relationship of the equations (34), (35), and (36), and the voltages across the two series windings inFIG.37are Va, Vb, and Vc. The reluctance motor RMCON continuously rotates in the CCW direction as explained by the above operation. InFIG.39, since the reluctance motor RMCON is not a simple model as described inFIG.47, a current increase/decrease time of 7.5° is created at a rotor rotation angle θr assuming high-speed rotation. In the time zone in which each phase current inFIG.39increases or decreases, the torque decreases slightly, and torque pulsation occurs even in a simple motor model. However, since the current increase/decrease time can be reduced at low speed rotation, the A-phase current Ia inFIG.39increases from 0 to 1.0 in the vicinity immediately before 0° of the rotor rotation angle position θr, as in the A-phase current Ia inFIG.47, and it can be modified and controlled so as to decrease from 1.0 to 0 in the vicinity immediately before 30°. As a result, in principle, the torque decrease and torque pulsation are reduced. Assuming the use of the motor for the main engine of an electric vehicle, the usage that requires the maximum torque is the uphill operation on a steep slope, the low-speed rotation of the motor, and the operating region of a large torque. Therefore, it is important to control the current increase/decrease time so as to be shortened at low speed rotation. There are often similar needs in industrial motor applications. Further, the torque generation width of each phase can be increased by increasing the circumferential width of the stator magnetic pole and the circumferential width of the rotor magnetic pole. Next, the drive characteristics of the drive circuit of the present invention and the reluctance motor RMCON ofFIG.37will be evaluated and described with respect to the supplied electric power. Since the rotor rotation angle position θr is between 0° and 22.5°, the A-phase current Ia inFIG.39is 1.0, and the B-phase current Ib and the C-phase current Ic are 0. From the relationship of the equations (13), (14), and (15), The AB phase current Iab of the AB phase full-pitch winding221and224and the CA phase current Ica of the CA phase full-pitch winding223and226ofFIG.22are 1.0, and the BC phase full-pitch winding222and the BC phase current Ibc of225is 0. This means that the winding377inFIG.37is energized with a current Iab=1.0 and the winding378is energized with a current Ica=1.0. Then, the current Ica=1.0 is applied to the winding378and the current Iab=1.0 is applied to the winding37A. The voltage across the series windings of windings377and378is (2×Va) according to equation (34). However, since the stator inFIG.22is a two-pole pair, the number of windings of each winding is set to ½, and the voltage across the windings377and378is set to 1.0 of Va. The voltage Va across the windings37B and37A is also 1.0. The power Pc01supplied to the two sets of the reluctance motor RMCON series windings when the rotor rotation angle position θr is between 0° and 22.5° s given by the following equation. Pc00=Va×Iax2=2×Vo×Io(40) Here, Vo is the value of Va in which Kra is 1 in Eq. (5), and Io is the current value to be energized. Further, at this time, the two sets of current paths have a circuit configuration that does not interfere with each other by the diodes37Q,37K,37L,37M,37N, and37P that block the opposite directions. Similarly, when the rotor rotation angle position θr is between 30° and 52.5°, the B-phase current Ib inFIG.39is 1.0, and the A-phase current Ia and the C-phase current Ic are 0. Therefore, the current Ibc of the AB phase windings221and224and the current Ibc of the BC phase windings222and225are 1.0, and the current Ica of the CA phase windings223and226is 0. This means that the winding377ofFIG.37is energized with a current Iab=1.0 and the winding37C is energized with a current Ibc=1.0. Then, the current Ibc=1.0 is applied to the winding379and the current Iab=1.0 is applied to the37A. The voltage across the series winding of windings377and37C is (2×Vb) from equation (36), but the number of windings is set to ½ as described above, and the voltage across the windings is 1.0 of Vb. The voltage across the windings379and37A is also 1.0 of Vb. The power Pc30supplied to the two sets of the series windings of the reluctance motor RMCON when the rotor rotation angle position θr is between 30° and 52.5° Is given by the following equation. Pc30=Vb×Ib×2=2×Vo×Io(41) Similarly, when the rotor rotation angle position θr is between 60° and 82.5°, the C-phase current Ic inFIG.39is 1.0, and the A-phase current Ia and the B-phase current Ib are 0. Therefore, the current Ibc of the BC phase windings222and225and the current Ica of the CA phase windings223and226are 1.0, and the current Iab of the AB phase windings221and224is 0. This means that the winding379ofFIG.37is energized with a current Ibc=1.0 and the winding378is energized with a current Ica=1.0. Then, the current Icc=1.0 is applied to the winding37B and the current Ibc=1.0 is applied to the37C. The voltage across the series windings of windings379and378is (2×Vc) from equation (35), but the number of turns is set to ½ as described above, and the voltage across the windings is 1.0 of Vc. The voltage across the lines37B and37C is also 1.0 of Vc. The power Pc60supplied to the two sets of the series windings of the reluctance motor RMCON when the rotor rotation angle position θr is between 60° and 82.5° is as follows. Pc60=Vc×Ic×2=2×Vo×Io(42) As described above, an example of driving the reluctance motor RMCON with the drive circuit of the present invention shown inFIG.37has been shown. The reluctance motor RMCON has a configuration of a stator magnetic pole ofFIG.22and a full-pitch winding, and has a rotor configuration of eight rotor magnetic poles by pairing the rotor ofFIG.46with the characteristics ofFIG.47. As shown inFIG.39and (40), (41), and (42), the totals of the currents Iab, Ibc, and Ica of full-pitch windings of each phase are always constant, and the maximum value of the current is the same as the currents Ia, Ib, and Ic when the winding is converted to concentrated winding. Therefore, since the resistance value of the full-pitch winding is ½ that of the concentrated windings, the copper loss can be reduced to ½, and the motor can be downsized and the cost can be reduced. In the drive circuit of the present invention ofFIG.37, since the voltage sums of the two windings in series shown inFIG.37are arranged in the relationships shown in the equations (34), (35), and (36), the voltage across the two windings is not complicated and does not generate an excessive voltage. Then, as shown in the equations (40), (41), and (42), power can be supplied in parallel through two sets of paths. Therefore, a comparison Is made with the case where the motor obtained by converting the reluctance motor RMCON into a centralized winding is driven by the conventional drive circuit shown inFIG.36, and the drive circuit of the present invention ofFIG.37can supply twice the power to the reluctance motor RMCON. Therefore, it is possible to reduce the size and cost of the drive circuit. Further, as described above, it is possible to reduce the current capacity to ½ and reduce the cost as compared with the drive circuit of the current mainstream three-phase AC permanent magnet application synchronous motor. Although the region of the current increase/decrease time inFIG.39has not been described in detail, as described above, the current increase/decrease time can be shortened at low speed rotation. Further, in the application of the main motor of an electric vehicle, a usage that requires a particularly large torque is a steep slope climbing operation, and since the rotation speed is low, the time for increasing or decreasing the current can be shortened. Twenty-Sixth Embodiment Next, as another embodiment of claim14, an example in which the motor shown inFIG.9(b)is driven by the drive circuit of the present invention ofFIG.40will be described. The reluctance motor shown inFIG.9(b)is a reluctance motor having 10 stator magnetic poles and 6 rotor magnetic poles, and the winding of each phase is a full-pitch winding. In the drive circuit of the present invention shown inFIGS.37and40, in order to cancel and control the voltage component as in equation (18) Induced in all the nodal windings, two offsetting windings are connected in series and controlled. The two offsetting windings are full-pitch winding windings of the respective slots arranged in the slots on both sides in the circumferential direction of the stator magnetic pole to be excited, and it becomes a voltage as in equations (16) and (17). Further, in the case of the drive circuit shown inFIGS.37and40, two or more windings of each phase are required. Since the reluctance motor shown inFIG.9(b)has a one-pole pair configuration, the full-pitch winding of each phase is divided into two insulated parallel windings, with two coil end symbols for each phase winding. If a two-pole pair full-pitch winding motor Is used, or if a toroidal winding is used as shown inFIG.23, it is not necessary to divide the winding in the same slot into two windings since two in-phase windings can be created. The respective currents inFIG.9(b)have the following relationships as in the equations (13), (14), and (15). Iac=Ia4+Ic4 (43) Ice=Ic4+Ie4 (44) Ieb=Ie4+Ib4 (45) Ibd=Ib4+Id4 (46) Ida=Id4+Ia4 (47) The left side of each equation is the current for full-pitch winding, and the right side is the current for concentrated winding. Further, in the method of dividing the in-phase winding into two, it is decided to make two full-pitch winding windings in which two concentrated winding windings are connected in series and which is ½ of the number of turns Nwa. The relationship between the voltage and the number of turns Nwa is shown by Eq. (5). It is controlled so that the current of the same value flows through these two windings having the same phase. The respective voltages ofFIG.9(b)have the following relationships as in the equations (34), (35), and (36). Vac+Vce=Vc4 (48) Vce+Veb=Ve4 (49) Veb+Vbd=Vb4 (50) Vbd+Vda=Vd4 (51) Vda+Vac=Va4 (52) The left side of each equation is the each phase voltage of the full-pitch winding, and the right side is the each phase voltage of the centralized winding ofFIG.9(a). As the number of phases of this 5-phase motor or the like increases, the magnetic flux component and the voltage component of the equation (18) increase, the voltage of the equation (18) becomes more complicated, and the voltage value becomes larger. FIG.40shows the drive circuit of the present invention that drives the reluctance motor shown inFIG.9(b). It is driven so as to satisfy the current conditions and voltage conditions of the above equations (43) to (52). It is driven so as to satisfy the current conditions and voltage conditions of the above equations (43) to (52). InFIG.40, a reference symbol13S shows a control circuit for the entire drive circuit, a reference symbol13R is a DC voltage source, and401,402,403,404,405,406,407,408,409, and a reference symbol40A are drive transistors. Regarding each winding and the energizing current, a reference symbol13ac1inFIG.40energizes the AC phase current lac of the formula (43) by the transistor401in the AC phase full-pitch winding13ac1ofFIG.9(b). Similarly, in13ce1ofFIG.40, the CE phase current Ice is energized by the transistor402in the CE-phase full-pitch winding13ce1ofFIG.9(b). Similarly, a reference symbol13eb1energizes the EB phase current Ieb by the transistor403in the EB phase full-pitch winding. A reference symbol13bd1is a BD-phase full-pitch winding, and the BD-phase current Ibd Is energized by the transistor404. A reference symbol13da1is a DA-phase full-pitch winding, and the DA-phase current Ida is energized by the transistor405. A reference symbol13ac2is an AC-phase full-pitch winding, and the AC-phase current lac is energized by the transistor406. A reference symbol13ce2is a CE-phase full-pitch winding, and the CE-phase current Ice is energized by a transistor407.13eb2is an EB-phase full-pitch winding, and an EB-phase current Ieb is energized by a transistor408. A reference symbol13bd2is a BD-phase full-pitch winding, and the BD-phase current Ibd is energized by the transistor409. A reference symbol13da2is a DA-phase full-pitch winding, and the DA-phase current Ida is energized by the transistor40A. As described above, in the drive circuit of the present invention ofFIG.40, a current is applied to each winding as in equations (43) to (47). In addition, each winding has two windings connected in series at the top and bottom on the paper ofFIG.40, and each winding is alternately connected to two electromagnetically related windings. The electromagnetic relationship means that inFIG.9(b), the two windings excite one of the stator magnetic poles, and two windings arranged in two slots on both sides of one of the stator magnetic poles in the circumferential direction. Then, the voltages of the two windings have a relationship corresponding to any of the equations (48) to (52). Further, each individual winding has a magnetic flux component and a voltage component of the equation (18), and generates an excessive voltage different from the voltage on the right side of the equations (48) to (52). Alternatively, when the current is PWM-controlled to increase or decrease the current, an excessive voltage is generated in each winding. The diodes40M,40N,40P,40Q,40R,40S,40T,40U,40V, and40W reduce the influence of the excessive voltage so as not to affect the other windings arranged on the left and right sides of the paper inFIG.40. Next, the current and voltage when the motor shown inFIG.9(b)is driven to rotate in the CCW direction by the drive circuit of the present invention ofFIG.40will be shown and described inFIG.41. The circumferential width of the stator magnetic pole is 18°, and the circumferential width θBr of the rotor magnetic pole is 24°. InFIGS.9(a) and9(b), the rotor rotation angle position where the rotor magnetic pole approaches the A-phase stator magnetic pole121during the CCW rotation is defined as θr=0°, and is shown at the bottom ofFIG.41. The phase currents ofFIG.9(b)are Iac, Ice, Ieb, Ibd, and Ida on the left side of equations (43) to (47), and their current waveforms are shown inFIG.41. Ia4, Ib4, Ic4, Id4, and Ie4ofFIG.41do not exist on the motor ofFIG.9(b), and the current components of the full-pitch winding as shown on the right side of equations (43) to (47). Since it is not easy to consider Iac, Ice, Ieb, Ibd, and Ida on the left side of equations (43) to (47), which are the currents of full-pitch windings, the current components are shown inFIG.41. Then, these current components Ia4, Ib4, Ic4, Id4, and Ie4are the phase currents of the concentrated winding wound around the stator magnetic poles of each phase ofFIG.9(a). When the rotor magnetic pole inFIG.9(b)approaches a point before 6 degrees to the A phase stator magnetic pole121, that is, when the rotor magnetic pole has θr=−6°, the A phase current component Ia4starts to increase from θr=−6°, and the A phase current Ia4is set to a predetermined value at θr=0°. During this period, the rotor magnetic pole does not face the A-phase stator magnetic pole121, and torque is not generated in a simple model. However, since it is a close distance, leakage flux is actually generated, and torque corresponding to the leakage flux is generated. During the period from θr=0° to 18°, the facing area between the A phase stator magnetic pole121and the rotor magnetic pole increases, and CCW torque is generated. Ia4is reduced from θr=18°, and Ia4is set to 0 at θr=24°. During this period, the entire surface of the A phase stator magnetic pole121faces the rotor magnetic pole, so no torque is generated. Similarly, during the period from θr=54° to 84°, the A phase current component Ia4Increases and decreases, and the process is repeated at a cycle of 60°. As shown in the figure, the other current components Ib4, Ic4, Id4, and Ie4are each delayed in phase by 12°. Each current period is 60°. The currents Iac, Ice, Ieb, Ibd, and Ida of the full-pitch winding winding ofFIG.9(b)have the relation of the equations (43) to (47) and have the waveform shown inFIG.41. AlthoughFIG.41shows an example in which the angle width at which the current increases/decreases is 6°, the current increase/decrease time can be shortened at low speed rotation, and conversely, it may be necessary to increase the current increase/decrease time at high speed rotation. Further, since the angle width and time of this current increase/decrease depend on the magnitude of the current, so they can be changed according to the operating conditions. Further, in order to shorten the time for increasing or decreasing the current, it is also possible to wind an exciting winding around each stator magnetic pole and connect it in series, energize a field current component, and circulate magnetic energy in the motor with rotation. As shown inFIG.30and the like, it is also possible to use a permanent magnet to excite and shorten the time for Increasing or decreasing the current. The AC phase voltage Vac, CE phase voltage Vce, EB phase voltage Veb, BD phase voltage Vbd, and DA phase voltage Vda of the full-pitch winding winding ofFIG.9(b)are related to the equations (16), (17), and (18), and in particular, Eq. (18) has a complicated voltage. Therefore, in the drive circuit of the present invention ofFIG.40, as in equations (48) to (52), two specific windings are connected in series, configured and controlled to have a relatively simple voltage on the right side of equations (48) to (52). These voltages Vc4, Ve4, Vb4, Vd4, and Va4are shown inFIG.41, and the values on the left side of the equations (48) to (52) are added in parentheses. For example, Va4inFIG.41is represented by the equation (52), and it corresponds to the A-phase voltage in which the concentrated winding winding91wound around the A-phase stator magnetic pole121ofFIG.9Aand the concentrated winding winding92wound around the A/ phase stator magnetic pole122are connected in series. Va4inFIG.41begins to Increase the A-phase current component Ia4from θr=−6° as described above. However, the A-phase stator magnetic pole121and the rotor magnetic pole are not yet opposed to each other, and since the interlinkage magnetic flux is a leakage flux, the generated voltage Is small, and the leakage flux increases as θr=0°, and Ia4increases to a predetermined value, so the A-phase voltage increases sharply. Then, from θr=0° to 18°, the facing area between the A stator magnetic pole and the rotor magnetic pole increases in synchronization with the rotation of the rotor, so that the voltage becomes constant. Since the current component Ia4is reduced from θr=18° to 24°, the magnetic energy related to the A-phase stator magnetic pole121and the A/ phase stator magnetic pole122is regenerated to the power source, and the A-phase voltage Va4during this period becomes a large negative voltage. During this period, no torque is generated because the entire surface of the A stator magnetic pole faces the rotor magnetic pole. Such voltage and operation are repeated at a cycle of 60°. Further, the voltages of the other phases also differ in the phase of the rotor rotation angle position by 12°, but have the same voltage waveform as shown in the figure. The torque Tt4in the operation ofFIG.41is a torque waveform that repeats 2.0 and 4.0 in a normalized torque value with a 12° cycle. Its average value is 3.0. The reluctance motor of the centralized winding ofFIG.9(a)can be driven by a drive circuit in which the half bridge ofFIG.36, which is a conventional drive circuit, is increased from 3 sets to 5 sets. Examples of the characteristics are shown inFIGS.12and13described above, and the normalized torque thereof is 1.5. In the winding configuration and winding connection of the drive circuit of the present invention ofFIG.40and the reluctance motor of the full-pitch winding ofFIG.9(b), it is possible to output twice as much torque and power as before, under the same conditions for the number of transistors. The torque Tt4inFIG.41is not preferable because the torque has a large torque ripple. This is also because the standard model of the reluctance motor with 10 stator magnetic poles and 6 rotor magnetic poles was used as an evaluation example. However, there are several ways to reduce this torque ripple. The first torque ripple reduction method is to modify the current waveform. For example, if the current waveforms of all phases are modified to the current waveforms shown by the broken line of Ia4inFIG.41, the torque is halved in the region where the torques of the other phases overlap. As a result, the total torque Tt4is 2.0, which is a uniform torque. Alternatively, the current value may be increased in the region where the torque of Tt4decreases. These may be combined. The second torque ripple reduction method is a method of correcting the circumferential widths of the stator magnetic pole and the rotor magnetic pole. For example, the stator magnetic pole width is set to 18°, but if it is corrected to 24°, the dent of the torque Tt4disappears, and the torque becomes uniform at 4.0. However, it should be noted that the current waveform of each phase also changes. The third torque ripple reduction method is a method of correcting the rotor axial widths of the stator magnetic pole and the rotor magnetic pole. For example, the torque ripple can be set to 0 by adopting the rotor magnetic pole shape as shown inFIGS.12and13. At this time, the rotor magnetic pole may be processed by processing the electromagnetic steel sheet as shown inFIG.17. In the rotor, this is a method of freely changing and setting the circumferential distribution of the magnetic resistance value per unit angle width in the radial direction over the entire rotor axial direction. Further, the first, second, and third torque ripple reduction methods may be combined. Next, the drive circuit of the present invention ofFIG.40, the winding configuration of the reluctance motor of the full-pitch winding ofFIG.9(b), and the effect on the winding connection will be summarized. Regarding the copper loss of the motor, the copper loss can be reduced by a maximum of ½ as compared with the reluctance motor of the concentrated winding. As described above, the main motor of an electric vehicle is a steep uphill operation, and a large torque at a low speed rotation is the most severe operation mode. The size of the motor is determined by the characteristics of this mode of operation, and most of the loss is copper loss. Therefore, by reducing the copper loss, it is possible to reduce the size, weight, and cost of the motor. In addition, the problem of full-pitch winding and toroidal winding was that that it is difficult for the conventional drive circuit in which the half bridge as shown inFIG.36is combined due to the influence of the complicated voltage and the excessive voltage as shown in the formulas (16), (17) and (18). The drive circuit and motor configuration of the present invention can solve this problem and output up to twice as much torque and power. Therefore, it is possible to reduce the size, weight, and cost of the drive circuit. As a comparison condition of the drive circuit, the total current capacity obtained by multiplying the current capacity of the transistors by the number of transistors is the same condition. Twenty-Seventh Embodiment Next, as another embodiment of claim14, an example in which the motor shown inFIG.8(b)is driven by the drive circuit of the present invention ofFIG.42will be described. The reluctance motor shown inFIG.8(b)is a reluctance motor having eight stator magnetic poles and six rotor magnetic poles, and the winding of each phase is a full-pitch winding. In the drive circuit of the present invention ofFIGS.37,40, and42, two offsetting windings are connected in series for control in order to cancel and control the voltage component as in the formula (18) induced in all the nodal windings. Therefore, two or more windings for each phase are required. The two offsetting windings are full-pitch windings of the respective slots arranged in the slots on both sides in the circumferential direction of the stator magnetic pole to be excited, and the voltage is as shown in formulas (16) and (17). Since the reluctance motor shown inFIG.8(b)has a one-pole pair configuration, the full-pitch winding of each phase is divided Into two insulated parallel windings, with two coil end symbols for each phase winding. Full-pitch winding windings11ad1and11ad2are AD phase windings that carry the AD phase current Iad,11dc1and11dc2energize the DC phase current Idc with the DC phase winding,11dc2energizes the DC phase current Idc with the DC phase winding,11ccb1and11ccb2energize the CB phase current Icb with the CB phase winding, and11ba1and11ba2energize the BA phase current Iba with the BA phase winding. The respective currents inFIG.8(b)have the following relationships which are based on the formulas (13), (14), (15), or (43), in the same way as (47). Iad=Ia3−Id3 (53) Idc=Id3+Ic3 (54) Icb=Ic3+Ib3 (55) Iba=Ib3+Ia3 (56) The left-hand side of each formula is the current for full-pitch winding, and the right-hand side is the current for concentrated winding. Only formula (53) has a different sign than the other formulas. In addition, the method of dividing the in-phase winding into two is to make two full-pitch windings that are ½ of the number of windings Nwa in which two concentrated winding windings are connected in series. The relationship between the voltage and the number of turns Nwa is shown by the formula (5). Each voltage ofFIG.8(b)has the following relationship as in the formulas (34), (35), (36), or (48) to (52). Vad+Vdc=Vd3 (57) Vdc+Vcb=Vc3 (58) Vcb+Vba=Vb3 (59) Vba+Vad=Va3 (60) The left-hand side of each formula is each phase voltage of the full-pitch winding, and the right-hand side is each phase voltage in the case of the concentrated winding ofFIG.8(a). FIG.42shows the drive circuit of the present invention that drives the reluctance motor shown inFIG.8(b). It is driven so as to satisfy the current conditions and voltage conditions of the above formulas (53) to (60). Here, the difference between the motor ofFIG.8and the motor ofFIGS.20and9is that a positive current and a negative current having different positive and negative signs flow through the slot between the stator magnetic poles101and108and the slot between102and107inFIG.8(a). Therefore, the value of the AD phase current lad in the formula (53) is both a positive value and a negative value. The drive circuit shown inFIG.42also needs to allow the lad to carry both positive and negative currents. A reference sign42S inFIG.42shows a control circuit for the entire drive circuit, a reference sign42R shows a DC voltage source, and reference signs421,422,423,424,425,426,427,428,428, and42A show drive transistors. The diodes40M,40N,40P,40Q,40R,40S,40T,40U,40V, and40W reduce affection of the other windings arranged on the left and right sides of the drawing paper ofFIG.42from the influence of the excessive voltage, and also limit the direction so of the current. The currents passing through these diodes are the phase electrical components on the right-hand side of formulas (53) to (56), and are indicated by the symbols in parentheses. The orientation of each winding inFIG.42is aligned with the energizing direction of each current. The relationship between the energizing current of each winding and the drive circuit ofFIG.42will be described. The winding11ad1ofFIG.42is indicated by the same symbol as the AD phase full-pitch winding11ad1ofFIG.8(b). The windings of the slot portions of11ad1and11ad2are the windings113and114ofFIG.8(b), and inFIG.8(a), the directions of the two currents in the slots are different. This winding113is the sum of the concentrated winding windings81and88ofFIG.8(a), and is expressed by the formula (53). Since it has a positive value and a negative value, its drive circuit becomes a little complicated. Of the AD phase current lad that energizes winding11ad1, the current component Ia3passes through the winding11ba2and the diode50B to the winding11ad1by the transistor42A, and is driven by the transistor422. The current component Id3of the AD phase current lad is driven by the transistor423through the winding11ad1by the transistor421, through the diode50C and the winding11dc1. As the current passing through the winding11ad1, the total current of the positive Ia3and the negative Id3is energized as shown in the formula (53). The current components Ia3and Id3may be superimposed. The current of formula (54) is driven by the transistor423to be supplied to the winding11dc1ofFIG.42. The current of the formula (55) is driven by the transistor424to be supplied to the winding11cb1. The current of formula (56) is driven by the transistor425to be supplied to the line11ba1. The energization of the windings11ad2,11dc2,11cab2, and11ba2shown inFIG.42is the same as the energization of the windings11ad1,11dc1,11cb1, and11ba1, because both of the energization paths are symmetrical to each other in the upper and lower parts of the drawing paper ofFIG.42. In this way, the drive circuit of the present invention can be realized even with positive and negative currents. However, as described above, 10 transistors are required for the 4-phase current control, and 2 transistors are required more than in the case ofFIGS.37and40in which the number of transistors is twice the number of phases. The current capacity of the transistors421,422,426, and427may be halved as compared with other transistors. The drive circuit of the present invention ofFIG.42, the reluctance motor of the full-pitch winding ofFIG.8(b), and the drive characteristics due to the unique winding configuration and connection are the same as those of the concentrated winding reluctance motor ofFIG.8(a), except for the difference in copper loss, the complexity of the winding voltage and the high voltage. In the case of the configuration of the stator magnetic pole and the rotor magnetic pole shown inFIG.10, the torque characteristics are as shown inFIG.11. It should be noted that various stator magnetic pole shapes, rotor magnetic pole shapes, and various current controls are possible, and the torque characteristics can be changed. The drive circuit of the present invention ofFIG.42, the reluctance motor of the full-pitch winding ofFIG.8(b), and the characteristics of driving by the unique winding configuration and connection are that the copper loss of the motor can be reduced to, at most, ½ of the copper loss caused in the conventional case, as in the case ofFIGS.37and40. Then, under the same conditions of the total current capacity of the transistors of the drive circuit, it is possible to output up to twice the torque and power. As a result, it is possible to reduce the size, weight, and cost of the motor and drive circuit. Twenty-Eighth Embodiment Next, an embodiment of claim15will be shown and described with reference toFIGS.43and44. Each winding shown inFIGS.43and44is a reluctance motor of the full-pitch winding shown inFIG.20. Three full-pitch windings and three diodes are connected in series in a delta shape in a ring shape to energize and control the current. The purpose of this configuration is to reduce motor copper loss in the so operating region LSHT where the torque is large at low speed rotation, to increase the output of the drive circuit in this operating region LSHT, to reduce the influence of the complicated voltage and the excessive voltage shown by the formulas (16), (17) and (18) in the operating region MSMT in which the torque is medium from the low speed rotation to the medium speed rotation. The drive circuit is simpler than that of the drive circuits ofFIGS.37,40, and42. However, it is relatively inferior in terms of torque and power output from medium to high speed rotation. Further, the number of phases of the drive circuit ofFIGS.43and44can be extended and applied to the reluctance motor having a large number of phases such as the part (b) ofFIG.8and the part (b) ofFIG.9. A reference sign43H inFIG.43shows a control circuit for the entire drive circuit, A reference sign43G shows a DC voltage source, and reference signs431,432,433,434,435, and436show drive transistors. A reference sign437show the AB phase full-pitch winding20D ofFIG.20, the AB phase current lab is energized.438is the BC phase full-pitch winding20E ofFIG.20, and carries the BC phase current Ibc. A reference sign439shows the CA-phase full-pitch winding20F ofFIG.20, which carries the CA-phase current Ica. Each current has a relationship of formulas (13), (14), and (15). A reference signs431,43K, and43L show diodes that interconnect the three-phase full-pitch windings437,438, and439to form a delta-shaped annular winding. Reference sign43A,43B,43C,43D,43E, and43F show diodes that are connected from both ends of the three-phase full-pitch winding windings437,438and439to both ends of the power supply to regenerate power. When the reluctance motor ofFIG.20rotates at a low speed, there is a margin in the power supply voltage, and the three-phase currents lac, Ibc, and Ica can be individually controlled. That is, the transistors431and432supply electric power to the AB phase full-pitch winding winding437to energize the current lab. In the next flywheel period, only the transistor431is turned on, and the current lab is circulated and held by the transistor431, the winding437, and the diode43A. In this flywheel, only the transistor432may be turned on. Similarly, the transistors433and434supply electric power to the BC phase full-pitch winding438to energize the current Ibc. Transistors435and436supply power to the CA-phase full-pitch winding439to energize the current Ica. At low speed rotation, the influence of other phases on the current control is smaller even with a large current and a large torque generated. That is, the same operation as the conventional drive circuit shown inFIG.36is possible. As a result, it is possible to reduce the motor copper loss in the operating region LSHT where the torque is large at low speed rotation, when compared with the concentrated winding reluctance motor ofFIG.1. Further, in this operating region LSHT, it Is possible to increase the output of the drive circuit because the power can be supplied by two paths out of the three phases. However, when the rotation speed of the reluctance motor shown inFIG.20increases and the current also increases, the voltage component of the formula (18) increases, the voltage difference of the formulas (16) and (17) increases, and the current control becomes difficult. For example, when the rotor approaches the rotation angle position ofFIG.20and outputs the CCW torque, the AB phase current lab is applied to the AB phase winding20D and the CA phase current Ica is applied to the CA phase winding20F. At this time, both windings have the voltages according to the formulas (16) and (17), and the voltage according to the formula (18) is generated in a differential manner. That is, the voltages caused by the B-phase magnetic flux φb and the C-phase magnetic flux φc is generated differentially. InFIG.43, as a countermeasure against the differential voltage generation, the voltage and current are controlled so that the CA phase winding20F and the AB phase winding20D compose a serial path. That is, a voltage can be applied to a series circuit of the transistor435, the CA phase winding439, the diode43L, the AB phase winding437, and the transistor432. At this time, the complexity of the voltage between the transistor435and the transistor432is eliminated, and the voltage according to the formula (34) is obtained. Similarly, as the rotor rotates, the current control can be performed by eliminating the complexity of the voltage by sequentially connecting the two windings in series and performing the current control. However, at the timing of performing current control by connecting two windings in series, the remaining one-phase winding often does not carry current. Therefore, when driving the region of high-speed rotation in the drive circuit ofFIG.43, it becomes impossible to supply electric power through two paths. In terms of power output performance, this is inferior to the winding and drive circuit configurations shown inFIG.37. As explained above, in the configuration ofFIG.43, it is possible to reduce motor copper loss in the operating region LSHT where the torque is large at low speed rotation, to increase the output of the drive circuit in this operating region LSHT, and to reduce the influence of the complicated voltage and the excessive voltage shown by the formulas (16), (17) and (18) in the operating region MSMT in which the torque is medium from the low speed rotation to the medium speed rotation. Twenty-Ninth Embodiment Next, in the configuration of the drive circuit ofFIG.44, compared toFIG.43, the power regeneration diodes43A,43B,43C,43D,43E and43F have been replaced by the diodes441,442,443,444,445and446ofFIG.44. The circuit operation is similar to that shown inFIG.43. The advantage is that the transistors and diodes are arranged in an inverse-parallel arrangement, so that a commercially available transistor module can be used. Functionally, there is a problem that the diode loss at the time of regeneration is doubled and the diode loss at the time of the flywheel is doubled, when being compared with those inFIG.43. In addition, it is necessary to consider the fact that the voltage of the other phases is affected during regeneration and flywheel, which is a problem. Thirtieth Embodiment Furthermore,FIG.44can be modified. The winding437and the diode43L are arranged in series at the position of the diode43L, and the emitter of the transistor431and the collector of the transistor432are connected. Then, the two phases of windings438and439are also replaced in the same manner. As a result of this replacement, a commercially available and mass-produced 6-piece transistor module can be used. There is a cost advantage. It should be noted that the modified drive circuit shown inFIGS.37,40,42,43,44,44is not only for driving the full-pitch winding, but also for the reluctance motor of the concentrated winding as shown inFIGS.1,46, and others can be driven. Thirty-First Embodiment Next, an embodiment of claim16will be shown and described with reference toFIG.45. In the reluctance motors shown inFIGS.1,8,9, etc., if the current of each phase is set to 0, the torque of the motor becomes 0, and the force acting between the stator magnetic poles of each phase and the rotor magnetic poles inside the motor is also 0. Even in the cases shown inFIGS.29,30, and31in which a permanent magnet is used, if the current of each phase is set to 0, the torque of the motor becomes 0 except for the torque ripple component. However, a large force is applied between the stator magnetic poles of each phase and the rotor magnetic poles inside the motor by the permanent magnets. The relationship is such that the torque Tccw in the CCW direction and the torque Tcw in the CW direction cancel each other out. Since these torque values Tccw and Tcw depend on the strength of the permanent magnet, when the permanent magnet is strengthened, the force may be equal to or higher than the rated torque. Therefore, when the CCW torque is generated, if the stator magnetic pole that can generate CCW torque can be excited and at the same time the torque Tcw force can be weakened in parallel, CCW torque can be generated more effectively. For example, in the reluctance motor ofFIG.29, when the rotor rotation angle position is shown, considering the state where the current of each phase is 0, magnetic flux is generated by the permanent magnets29A and29B, and the torques Tccw and Tcw are generated so as to cancel each other out. Specifically, when the A8 phase stator magnetic pole291passes through the rotor magnetic pole, the magnetic flux φaccw passes through the A8/ phase stator magnetic pole292, so that the CCW direction torque Tccw is generated. On the other hand, when the B8 phase stator magnetic pole293passes through the rotor magnetic pole, the magnetic flux φbcw passes through the B8/ phase stator magnetic pole294, so that a torque Tcw in the CW direction is generated. The total torque is offset by (Tccw−Tcw)=0. Next, in order to generate the torque of CCW, the A8 phase current Ia8can be applied to the A8 phase stator pole291and the A8/ phase stator pole292to generate the torque Ta8. At this time, as another method of generating the torque in the CCW direction, there is a method of energizing the B8 phase stator magnetic pole293and the B8/ phase stator magnetic pole296with a negative value B8 phase current Ib8. For example, when Ib8Is −5 [A], assuming that the CW direction torque Tcw Is reduced to ½, when the A8 phase current Ia8and the B8 phase current Ib8=−5 [A] are energized, the total torque becomes (Ta8+(Tccw−Tcw/2))=(Ta8+Tcw/2). That is, a negative current −5 [A] is applied to the B8 phase current Ib8to obtain a torque of Tcw/2 in the CCW direction. In this way, in order to increase the total torque Tt8, by setting the B8 phase current Ib8to a negative current value, the magnetic flux φbcw can be reduced, the torque Tcw in the CW direction can be reduced, and the torque Tt8generated by the motor can be increased. By controlling the respective phase currents in this way with the rotation of the rotor, the torque component Tcw in the CW direction can be continuously reduced. FIG.45is an example of a drive circuit capable of controlling the phase currents Ia8, Ib8, and Ic8ofFIG.29to positive and negative values. A reference sign45H inFIG.45shows a control circuit for the entire drive circuit, and a reference sign45G shows a DC voltage source. A reference sign45D shows an A8 phase winding, a reference sign45E shows a B8 phase winding, and a reference sign45F shows a C8 phase winding. The positive current of the A8 phase current Ia8is driven by the transistors451and454, and the negative current is driven by the transistors453and452. The positive current of the B8 phase current Ib8is driven by the transistors455and458, and the negative current is driven by457and456. The positive current of the C8 phase current Ic8is driven by the transistors459and45C, and the negative current is driven by45B and45A. With the drive circuit ofFIG.45, not only the positive value of each phase current but also the negative current is applied in the section that has not been energized until now to generate the CCW torque, so that the positive current value can be reduced. Also, since the usage rate of each phase winding is improved, the total copper loss of the motor can be reduced. Further, the drive circuit ofFIG.45has more elements than the conventional drive circuit ofFIG.36. However, as a countermeasure, the maximum value of the negative current of each phase is smaller than the positive current value, so it is also possible to reduce the current capacity of the transistors453,452,457,456,45B, and45A to reduce the burden of increasing the drive circuit. In each figure shown as the reluctance motor of the present invention, the direction of the energized current is indicated by a current symbol, and the N polarity and the S polarity of the stator magnetic poles are added, but a current in the direction opposite to the current symbol is also energized in claim16. Further, the drive circuit ofFIG.45is converted by the formulas (13), (14) and (15), and can be applied to a motor with a full-pitch winding. Although the present invention has been described above, it is possible to combine the techniques according to the claims, various modifications, and applications. For example, not only the noise is reduced, but also the copper loss is reduced as a full-pitch winding, and the reluctance motor of the full-pitch winding shown inFIG.20. Also, the rotor configuration ofFIG.6is composed of electrical steel sheets as shown inFIG.17(b)to improve productivity and magnetic characteristics, and a permanent magnet between the teeth shown inFIG.26is applied to reduce iron loss and increase the slot cross-sectional area to reduce copper loss. Further, the torque characteristics are improved by locally utilizing permendur with high magnetic flux density as shown inFIG.27, the permanent magnet can be used for excitation as shown inFIG.30or31, and the drive circuit ofFIG.37can also reduce the size of the inverter. These technologies are interrelated and can be used together to make a highly competitive reluctance motor. As a result, it is possible to reduce noise, reduce torque ripples, increase a peak torque, and utilize the high-speed rotation range. Further, by reducing the copper loss of the reluctance motor and driving circuit with high utilization efficiency, it is possible to realize miniaturization, weight reduction, and manufacturing cost reduction. The individual techniques can also be applied to the conventional reluctance motor shown inFIG.46. The number of phases of the motor can be expanded not only to the three-phase, four-phase, and five-phase shown in the figure, but also to seven-phase, eleven-phase, etc., and can be combined with the number of rotor magnetic poles, multi-polarized, and the like. The motor type can also be transformed into an outer rotor type motor, an axial gap type motor, a linear motor, or the like, and can be combined with other types of motors. It is also possible to change the permanent magnet with the current for the motor, or to change the permanent magnet with a dedicated device. It is also possible to utilize sensor-less position detection technology that utilizes the fact that the induced voltage and magnetic characteristics of each winding change with the rotation of the rotor. INDUSTRIAL USABILITY According to the present invention, it is possible to reduce noise, reduce torque ripples, increase a peak torque, and utilize a high-speed rotation range. Further, by reducing the copper loss of the reluctance motor and driving circuit with high utilization efficiency, it is possible to realize miniaturization, weight reduction, and manufacturing cost reduction. The reluctance motor of the present invention has a configuration and characteristics that prioritize the torque of one-way rotation, but there are many applications in which one-way rotation characteristics are particularly important in motors for main engines of electric vehicles, industrial motors, motors for home appliances, and the like. REFERENCE SIGNS LIST 11A1 phase stator magnetic pole12A1/ phase stator magnetic pole13B1 phase stator magnetic pole14B1/ phase stator magnetic pole15C1 phase stator magnetic pole16C1/ phase stator magnetic pole17,18A1 phase winding1C,1D A1/ phase winding1U,1V B1 phase winding1S,1T B1/ phase winding1Q,1R C1 phase winding1P,1N C1/ phase winding19stator1B rotor shaft1J,1K,1L,1M example of lateral section of rotor magnetic pole4J,4K,4L,4M linearly developed shape along air-gap surface of rotor magnetic polesθr rotation angle position of rotorθBr circumferential angular width of rotor magnetic pole | 288,603 |
11863019 | FIG.1is a plan view of a first embodiment of a rotor lamination1, which is subdivided into a plurality of equidistant sectors2ato2hof the same size. The number of sectors2ato2hin this example is eight. Each sector2ato2hhas a first half-sector3and a second half-sector5separated from the first half-sector3by a separation plane4. The first half-sector3has a first through-opening6and a second through-opening7. The second half-sector5has a further through-opening8formed mirror-symmetrically to the first through-opening6, and a further through-opening9formed mirror symmetrically to the second through-opening7, in each case with respect to the separation plane4. Due to the symmetry of the through-openings6to9, only the through-openings6and7in sector2aprovided in the first half-sector3are described below, and are therefore also representative of the half-sectors3,5of other sectors2bto2g. FIG.2is a plan view of the first half-sector3of sector2a. The first through-opening6has a first leg side10, of which the imaginary extension11intersects the separation plane4at an acute angle12. A second leg side13of the first through-opening6runs parallel to the first leg side10. An imaginary extension14of the second leg side13intersects the separation plane4radially further outwards than the imaginary extension11of the first leg side10. The first through-opening6has an edge15which connects an end16of the first leg side10furthest away from the separation plane4to an end17of the second leg side13furthest away from the separation plane4. FIG.3is a detailed view of the edge15of the first through-opening6. The edge15has an equidistant portion18, which is equidistant to an outer contour19of the rotor lamination1. A distance20between the equidistant portion18and the outer contour19is therefore constant in the radial direction over a certain angular range in the circumferential direction. A length of a chord of the equidistant portion corresponds substantially to the distance between the leg sides10,13. Furthermore, the edge15has a projection21, pointing into the through-opening6in the transition of the edge to the equidistant portion18as seen from the first leg side10, and a rebate22between the projection21and the equidistant portion18. The rebate22is delimited by an imaginary line23, which runs parallel to the first leg side10and intersects the separation plane4(seeFIG.2) radially further inwards than the imaginary extension11of the first leg side10. Between the projection21and the rebate22, the edge15has a straight portion24, which runs parallel to the imaginary extension11of the first leg side10, but may alternatively also be oblique. A distance between the straight portion24and the imaginary line23is approximately 1.3 times the distance between the straight portion24and the imaginary extension11of the first leg side10. Between the rebate22and the equidistant portion18, the edge15has another straight portion25which extends along the imaginary line23. Transitions from the end16of the first leg portion to the projection21, from the projection21to the straight portion24, from the straight portion24to the rebate22, from the rebate22to the straight portion25and from the straight portion24to the equidistant portion18are each formed by a rounding of which the radius of curvature is smaller than that of the equidistant portion18. Such a rounding also forms the transition from the end17of the second leg side13to the equidistant portion18. Again with reference toFIG.2, the second through-opening7has a first leg side26, of which the imaginary extension27intersects the separation plane4at a radially outwardly open acute angle28radially further outwards than the second leg side13of the first through-opening6. The angle28is greater than the angle12in the present case. A second leg side29of the second through-opening7runs parallel to the first leg side26. An imaginary extension30of the second leg side29intersects the separation plane4radially further outwards than the imaginary extension27of the first leg side of the second through-opening7. The following second and third embodiment of a rotor lamination1differs from the first embodiment according toFIG.1toFIG.3only in the design of edge15, and therefore all previous comments with regard to the first embodiment may be transferred to these embodiments, unless otherwise described in the following. FIG.4is a detailed view of the edge15of the first through-opening6of the second embodiment of the rotor lamination1. The rebate22extends here to the imaginary extension11of the first leg side10. The chord of the equidistant portion18is thus somewhat shorter than in the first embodiment. FIG.5is a detailed view of the edge15of the first through-opening6of the third embodiment of the rotor lamination1. Here, the edge15between the projection21and the equidistant portion18runs along a straight portion31, which is parallel to the imaginary extension11of the first leg side10, but may alternatively also be oblique. Transitions from the projection21to the straight portion31and from the straight portion31to the equidistant portion18are each formed by a rounding of which the radius of curvature is smaller than that of the equidistant portion18. The chord of the equidistant portion18is slightly shorter than in the second embodiment. FIG.6is a basic sketch of an embodiment of an electric machine32, comprising a stator33and an embodiment of a rotor34mounted inside the stator33. The rotor34comprises an embodiment of a laminated core35, which is formed from a plurality of layered and laminated rotor laminations1according to one of the embodiments described above. The through-openings6to9of each rotor lamination are arranged congruently one above the other, so that they form magnet pockets of the rotor laminated core35for permanent magnets36of the rotor34. FIG.7is a plan view of a half-sector3aof a rotor lamination1aaccording to the prior art, in which an edge15aof a through-opening6aclearly does not have an equidistant portion. Apart from this, rotor lamination1a corresponds substantially to the first embodiment of the rotor lamination1. It was determined by simulation that, during rotating operation at a speed of 16,000 min−1of an electric machine corresponding toFIG.6, which is constructed on the basis of the rotor lamination1a, a maximum of mechanical stress of approx. 424 MPa is present in a bridge area37between the edge15aand an outer contour19aof the rotor lamination1a. By contrast, the maximum mechanical stress in such a bridge area is approx. 410 MPa in the third embodiment, approx. 370 MPa in the second embodiment, and approx. 337 MPa in the first embodiment, so that reductions of the maximum mechanical stress of 3.3 percent, 12.7 percent and 20.5 percent respectively may be achieved by the equidistant portions18. FIG.8is a basic sketch of an embodiment of a vehicle38, comprising an embodiment of an electric machine32according toFIG.6which is designed to drive the vehicle38. The vehicle38may be a battery electric vehicle (BEV) or a hybrid vehicle. | 7,091 |
11863020 | DETAILED DESCRIPTION Embodiments of the present invention will be described in detail below with reference to the figures. In this regard, the present invention is not limited to these embodiments. First Embodiment Configuration of Compressor FIG.1is a longitudinal sectional view illustrating a compressor300of a first embodiment. The compressor300is a rotary compressor, and is used in, for example, an air conditioner400(FIG.16). The compressor300includes a compression mechanism portion301, a motor100that drives the compression mechanism portion301, a shaft41that connects the compression mechanism portion301and the motor100, and a sealed container307that accommodates these components. In this example, an axial direction of the shaft41is a vertical direction, and the motor100is disposed above the compression mechanism portion301. Hereinafter, a direction of a center axis C1, which is a rotation center of the shaft41, is referred to as an “axial direction”. A radial direction about the center axis C1is referred to as a “radial direction”. A circumferential direction about the center axis C1is referred to as a “circumferential direction” and indicated by an arrow S inFIG.2and other figures. A sectional view on a plane parallel to the center axis C1is referred to as a “longitudinal sectional view”, whereas a sectional view on a plane perpendicular to the center axis C1is referred to as a “cross-sectional view”. The sealed container307is a container formed of a steel sheet and has a cylindrical shell and a container top that covers the top of the shell. A stator5of the motor100is incorporated inside the shell of the sealed container307by shrink-fitting, press fitting, welding, or the like. The container top of the sealed container307is provided with a discharge pipe312for discharging refrigerant to the outside and terminals311for supplying electric power to the motor100. An accumulator310that stores refrigerant gas is attached to the outside of the sealed container307. At the bottom of the sealed container307, refrigerant machine oil for lubricating bearings of the compression mechanism portion301is stored. The compression mechanism portion301includes a cylinder302having a cylinder chamber303, a rolling piston304fixed to the shaft41, a vane dividing the inside of the cylinder chamber303into a suction side and a compression side, and an upper frame305and a lower frame306which close both ends of the cylinder chamber303in the axial direction. Both the upper frame305and the lower frame306have bearings that rotatably support the shaft41. An upper discharge muffler308and a lower discharge muffler309are mounted to the upper frame305and the lower frame306, respectively. The cylinder302is provided with the cylinder chamber303having a cylindrical shape about the center axis C1. An eccentric shaft portion41aof the shaft41is located inside the cylinder chamber303. The eccentric shaft portion41ahas a center which is eccentric with respect to the center axis C1. The rolling piston304is fitted to the outer circumference of the eccentric shaft portion41a. When the motor100rotates, the eccentric shaft portion41aand the rolling piston304rotate eccentrically in the cylinder chamber303. The cylinder302is provided with a suction port315through which the refrigerant gas is sucked into the cylinder chamber303. A suction pipe313that communicates with the suction port315is attached to the sealed container307. The refrigerant gas is supplied from the accumulator310to the cylinder chamber303via the suction pipe313. The compressor300is supplied with a mixture of low-pressure refrigerant gas and liquid refrigerant from a refrigerant circuit of the air conditioner400(FIG.16). If the liquid refrigerant flows into and is compressed by the compression mechanism portion301, it may cause the failure of the compression mechanism portion301. Thus, the accumulator310separates the refrigerant into the liquid refrigerant and the refrigerant gas, and supplies only the refrigerant gas to the compression mechanism portion301. For example, R410A, R407C, R22 or the like may be used as the refrigerant, but it is desirable to use refrigerant with a low global warming potential (GWP) from the viewpoint of preventing global warming. Examples of the low GWP refrigerant are described below. (1) First, a halogenated hydrocarbon having a carbon-carbon double bond in its composition, for example, HFO (Hydro-Fluoro-Olefin)-1234yf (CF3CF═CH2), can be used. The GWP of HFO-1234yf is four. (2) Alternatively, a hydrocarbon having a carbon-carbon double bond in its composition, for example, R1270 (propylene), may be used. The GWP of R1270 is three, which is lower than that of HFO-1234yf, but R1270 has higher flammability than HFO-1234yf. (3) A mixture containing at least one of a halogenated hydrocarbon having a carbon-carbon double bond in its composition and a hydrocarbon having a carbon-carbon double bond in its composition may be used. For example, a mixture of HFO-1234yf and R32 may be used. HFO-1234yf described above is a low-pressure refrigerant and thus tends to increase a pressure drop, which may lead to reduction in the performance of a refrigeration cycle (particularly, an evaporator). Thus, it is practically desirable to use a mixture of HFO-1234yf with R32 or R41, which is a higher pressure refrigerant than HFO-1234yf. Configuration of Motor FIG.2is a cross-sectional view illustrating the motor100.FIG.2is the cross-sectional view on a plane that passes through a facing region101(FIG.3) described later. The motor100is called an inner-rotor type motor, and includes a rotor1and the stator5provided so as to surround the rotor1from an outer side in the radial direction. An air gap of, for example, 0.3 to 1.0 mm, is provided between the rotor1and the stator5. The rotor1has a cylindrical rotor core10and permanent magnets3attached to the rotor core10. The rotor core10is formed of a plurality of steel laminations which are stacked in the axial direction and integrated together by crimping or the like. Each of the steel laminations is, for example, an electromagnetic steel sheet. The sheet thickness of each of the steel laminations is, for example, 0.1 to 0.7 mm, and is 0.35 mm in this example. A shaft hole14is formed at a center of the rotor core10in the radial direction. The above-described shaft41is fixed to the shaft hole14by shrink-fitting, press-fitting, bonding, or the like. A plurality of magnet insertion holes11into which the permanent magnets3are inserted are formed along an outer circumference of the rotor core10. One magnet insertion hole11corresponds to one magnetic pole, and a space between adjacent magnetic insertion holes11is an inter-pole portion. The number of magnet insertion holes11is six in this example. In other words, the number of magnetic poles is six. The number of magnetic poles is not limited to six and only needs to be two or more. Each magnet insertion hole11extends linearly in a plane perpendicular to the axial direction. One permanent magnet3is inserted in each magnet insertion hole11. The permanent magnet3is in the form of a flat-plate, and has a length in the axial direction of the rotor core10, a width in the circumferential direction, and a thickness in the radial direction. The permanent magnet3is made of a rare earth magnet that contains, for example, neodymium (Nd), iron (Fe) and boron (B) as main components. Each permanent magnet3is magnetized in the thickness direction. The permanent magnets3inserted into the adjacent magnet insertion holes11have opposite magnetic poles on the outer side in the radial direction. Each magnet insertion hole11may have, for example, a V shape. Two or more permanent magnets3may be disposed in each magnet insertion hole11. In the rotor core10, an opening12(FIG.4(B)) as a flux barrier is formed at each end of the magnet insertion hole11in the circumferential direction. A thin wall portion20(FIG.4(B)) is formed between each opening12and the outer circumference of the rotor core10. The thin wall portion20is formed so as to suppress short-circuit magnetic flux flowing between adjacent magnetic poles. The thin wall portion20has a minimum width W, which is the same as the sheet thickness of the steel lamination, for example. As the minimum width W of the thin wall portion20decreases, the effect of suppressing the short-circuit magnetic flux flowing between the adjacent magnetic poles increases. In the rotor core10, at least one slit13is formed between the magnetic insertion hole11and the outer circumference of the rotor core10. The slit13is formed to reduce an increase in iron loss due to rotating magnetic field from the stator5and also reduce vibration and noise due to a magnetic attractive force. In this example, five slits13are symmetrically disposed with respect to a center of the magnet insertion hole11in the circumferential direction, i.e., a pole center. The number and arrangement of the slits13are not limited. In the rotor core10, through holes18and19are formed on the inner side with respect to the magnet insertion hole11in the radial direction. Each of the through holes18is formed at a position corresponding to the inter-pole portion in the circumferential direction. Each of the through holes19is formed at a position corresponding to the pole center in the circumferential direction and on the outer side with respect to the through hole18in the radial direction. The through holes18and19are used as airholes through which the refrigerant passes or as holes through which jigs are inserted. Although six through holes18and six through holes19are formed in this example, the number and arrangement of the through holes18and19are not limited. A balance weight42is fixed to an end of the rotor core10in the axial direction, and a balance weight43is fixed to the other end of the rotor core10in the axial direction. The balance weights42and43are disc-shaped and made of brass, for example. The balance weights42and43(FIG.1) are provided to increase the inertia of the rotor1and to improve the rotational balance of the rotor1. The stator5includes a stator core50and coils55wound on the stator core50. The stator core50is formed of a plurality of steel laminations which are stacked in the axial direction and integrated together by crimping or the like. Each of the steel laminations is, for example, an electromagnetic steel sheet. The sheet thickness of each of the steel laminations is 0.1 to 0.5 mm, and is 0.35 mm in this example. The stator core50has a yoke51having an annular shape about the center axis C1and a plurality of teeth52extending inward in the radial direction from the yoke51. The teeth52are arranged at regular intervals in the circumferential direction. The number of teeth52is nine in this example. The number of teeth52is not limited to nine, and only needs to be two or more. A slot53, which is a space to accommodate the coil55, is formed between the teeth52adjacent to each other in the circumferential direction. The number of slots53is the same as the number of teeth52, which is nine in this example. That is, the ratio of the number of magnetic poles to the number of slots in the motor100is 2:3. In this example, the stator core50has a configuration in which a plurality of split cores5A each including one tooth52are connected together in the circumferential direction. The split cores5A are connected to one another at connecting portions51aprovided at an outer circumferential end of the yoke51. This configuration makes it possible to wind the coils55around the teeth52while the stator core50is expanded in a band shape. The stator core50is not limited to the configuration in which the split cores5A are connected. The coil55is formed of a magnet wire wound around each tooth52in a concentrated winding. The wire diameter of the magnet wire is, for example, 0.8 mm. The number of turns of the coil55around one tooth52is, for example, 70 turns. The number of turns and the wire diameter of the coil55are determined according to required specifications of the motor100such as the number of revolutions and torque, a supplied voltage, or a sectional area of the slot53. The coils55have winding portions of three phases, i.e., a U-phase, a V-phase, and a W-phase, which are connected in Y-connection. An insulating portion54(FIG.1) formed of resin such as liquid crystal polymer (LCP) is provided between the stator core and the coil55. The insulating portion54is formed by attaching a resin molded body to the stator core50or integrally molding the stator core50with resin. Although not illustrated inFIG.2, an insulating film having a thickness of 0.1 to 0.2 mm and formed of resin such as polyethylene terephthalate (PET) is provided on the inner surface of the slot53. FIG.3is a longitudinal sectional view illustrating the motor100. Ends of the rotor core10and the stator core50on the compression mechanism portion301(FIG.1) side, i.e., lower ends of the rotor core10and the stator core50, are located at the same position in the axial direction. A length of the stator core50in the axial direction is, for example, 25 mm, whereas a length of the rotor core10in the axial direction is, for example, 32 mm. Thus, the rotor core10protrudes from the stator core50on the opposite side to the compression mechanism portion301in the axial direction by, for example, 7 mm (FIG.1). That is, the rotor core10has the facing region101where the rotor core10faces the stator core50and an overhang region102where the rotor core10protrudes from the stator core50in the axial direction. The overhang region102is a region within a range of 7 mm from an upper end of the rotor core10, i.e., an end of the rotor core10opposite to the compression mechanism portion301. In this example, an outer diameter of the stator core50is 110 mm, and an inner diameter of the stator core50is 56 mm. An outer diameter of the facing region101of the rotor core10is 54.5 mm. Thus, an air gap of 0.75 mm is formed between the facing region101of the rotor core10and the stator core50. An outer diameter of a part of the overhang region102within a range of 6 mm from the upper end of the rotor core10is 60 mm. That is, the rotor core10hangs over the stator core50as illustrated inFIG.3. FIG.4(A)is a cross-sectional view illustrating a cross-sectional shape of the overhang region102of the rotor1, andFIG.4(B)is a cross-sectional view illustrating a cross-sectional shape of the facing region101of the rotor1. InFIGS.4(A) and4(B), reference character P denotes the pole center of the rotor1, and reference character M denotes the inter-pole portion. As illustrated inFIG.4(B), an outer circumference15of the facing region101of the rotor1has a circular shape about the center axis C1. That is, a distance R1from the center axis C1to the outer circumference15is constant in the circumferential direction. The minimum width W of the thin wall portion20between the opening12and the outer circumference15is 0.35 mm, which is the same as the sheet thickness of the steel lamination. As illustrated inFIG.4(A), the outer circumference of the overhang region102of the rotor1includes outer circumference portions17located on the outer side of the magnet insertion holes11in the radial direction and outer circumference portions16located on the outer side of the openings12in the radial direction. Each outer circumference portion17includes the pole center P, while each outer circumference portion16includes the inter-pole portion M. The outer circumference portions16and17are both formed in the circumferential direction about the center axis C1. The outer circumference portion17protrudes outward in the radial direction with respect to the outer circumference portion16. A distance R2from the center axis C1to the outer circumference portion17is longer than the above-described distance R1. Meanwhile, a distance from the center axis C1to the outer circumference portion16is the same as the above-described distance R1. Thus, the minimum width W of the thin wall portion20between the opening12and the outer circumference portion16is the same as the minimum width W of the thin wall portion20in the facing region101, and is 0.35 mm, for example. FIG.5is a diagram illustrating the facing region101and the overhang region102of the rotor core10in such a manner that the regions101and102overlap each other. In the overhang region102of the rotor core10, the outer circumference portion located on the outer side in the radial direction of the magnet insertion hole11protrudes outward in the radial direction with respect to the outer circumference15of the facing region101. In the overhang region102of the rotor core10, the outer circumference portion16located on the outer side in the radial direction of the thin wall portion20is located at the same position in the radial direction as the outer circumference15in the facing region101. That is, the maximum outer diameter of the overhang region102of the rotor core10is larger than the maximum outer diameter of the facing region101, but the minimum width W of the thin wall portion20is the same in the overhang region102and in the facing region101. When the weight of the cylindrical rotor core10is represented by “m”, the radius of the cylindrical rotor core10is represented by “r”, the length of the cylindrical rotor core10in the axial direction is represented by “h”, and the density of the rotor core10is represented by “ρ”, m=ρ×πr2×h is satisfied. The inertia I of a cylinder about the center axis C1is expressed as I=½×(mr2)=π/2×ρ×h×r4. That is, the inertia of the rotor core10is proportional to the length h in the axial direction and also proportional to the fourth power of the radius r. Thus, the inertia of the rotor core10can be increased by increasing the outer diameter of the overhang region102of the rotor core10. This makes it possible to stabilize the rotation of the rotor core10against load pulsation of the compression mechanism portion301and to suppress vibration and noise. Further, the distance between the rotor core10and the stator core50is reduced by increasing the outer diameter of the overhang region102of the rotor core10. This increases the amount of the magnetic flux of the permanent magnets3interlinked with the coils55. Thus, the motor efficiency can be improved, and the motor100can be further made compact. In addition, since the minimum width W of the thin wall portion20is the same in the overhang region102and in the facing region101, short-circuit magnetic flux between adjacent magnetic poles can be suppressed. In the manufacturing process of the compressor300, each of the stator5and the compression mechanism portion301is fixed to the inside of the cylindrical shell of the sealed container307by shrink-fitting. The shaft41is incorporated in the compression mechanism portion301in advance. Then, in a state where the shaft hole14is widened by heating the rotor1, the shaft41is fitted into the shaft hole14of the rotor1while the rotor1is inserted into the inside of the stator5. The overhang region102of the rotor core10has a large outer diameter but is formed on the opposite side to the compression mechanism portion301. Thus, the rotor1can be inserted into the inside of the stator5from the opposite side to the compression mechanism portion301, and thus the compressor300can be easily assembled and the productivity can be improved. Operation of Compressor Next, the operation of the compressor300will be described. When current is supplied to the coils55of the stator5through the terminals311, the rotating magnetic field generated by the current and the magnetic field of the permanent magnets3of the rotor1generate attractive and repulsive forces between the stator5and the rotor1, causing the rotor1to rotate. The shaft41fixed to the rotor1also rotates accordingly. Low-pressure refrigerant gas is sucked from the accumulator310into the cylinder chamber303of the compression mechanism portion301through the suction port315. Within the cylinder chamber303, the eccentric shaft portion41aof the shaft41and the rolling piston304attached to the eccentric shaft portion41arotate eccentrically, thereby compressing the refrigerant in the cylinder chamber303. The refrigerant compressed in the cylinder chamber303is discharged into the sealed container307through a discharge port (not shown) and the discharge mufflers308and309. The refrigerant discharged into the sealed container307rises in the sealed container307through the through holes18and19of the rotor core10and the like, and is then discharged through the discharge pipe312and supplied to a refrigerant circuit of the air conditioner400(FIG.16). Function A function of the first embodiment will be described by comparison with a comparative example. In the compressor300, the compression mechanism portion301repeatedly sucks and compresses the refrigerant, causing a load on the motor100to pulsate. In particular, in the compact motor100, the rotor1is small in size and light in weight, and thus the inertia is small. Therefore, the rotation of the rotor1may be unstable due to the load pulsation. In order to increase the inertia of the rotor1, it is necessary to increase the size of the rotor core10. However, in order to increase the outer diameter of the rotor core10, it is also necessary to increase the inner diameter of the stator core50surrounding the rotor core10. When the inner diameter of the stator core50is increased, the area of the slots53decreases, and accommodation spaces for the coils55are reduced. Thus, it is necessary to reduce the cross-sectional area of conductors of the coils55, which increases copper loss and leads to reduction in the motor efficiency. In addition, when both the inner and outer diameters of the stator core50are increased, the sealed container307into which the stator core50is fitted needs to be made larger, which increases the size of the compressor300. Therefore, it is conceivable to increase the inertial of the rotor1by making the rotor core10protrude from the stator core50in the axial direction. FIG.6(A)is a longitudinal sectional view illustrating a motor100F of a comparative example.FIG.6(B)is a cross-sectional view illustrating a rotor1F of the motor100F of the comparative example. For convenience of description, components of the motor100F in the comparative example are denoted with the same reference characters as those of the first embodiment. In the motor100F of the comparative example, the rotor core10of the rotor1F protrudes from the stator core50in the axial direction, but the outer diameter of the rotor core10is constant in the axial direction. That is, the rotor1F has the cross-sectional shape shown inFIG.6(B)at any position in the axial direction. The cross-sectional shape illustrated inFIG.6(B)is the same as the cross-sectional shape of the facing region101of the rotor1illustrated inFIG.4(B). In the motor100F of the comparative example, the inertia of the rotor1F is increased by increasing the length of the rotor core10in the axial direction. However, the distance from the stator core50to the overhang region where the rotor core10protrudes from the stator core50is long. As a result, part of the magnetic flux of the permanent magnets3is not effectively interlinked with the coils55, and thus the motor efficiency is reduced. On the other hand, in the first embodiment, the inertia of the rotor core10can be increased by increasing the outer diameter of the overhang region102of the rotor core10. This makes it possible to stabilize the rotation of the rotor core10against the load pulsation of the compression mechanism portion301. In addition, since the distance of the overhang region102of the rotor core10from the stator core50is shortened, the amount of the magnetic flux of the permanent magnet3interlinked with the coils55increases, thus the motor efficiency is improved. In the comparative example illustrated inFIGS.6(A) and6(B), the length of the stator core50in the axial direction is 25 mm, whereas the length of the rotor core10in the axial direction is 35 mm. The overhang amount is 10 mm. The outer diameter of the stator core50is 110 mm, the inner diameter of the stator core50is 56 mm, and the outer diameter of the rotor core10is 54.5 mm. In contrast, in a particular example of the first embodiment, the length of the stator core50in the axial direction is 25 mm, and the length of the rotor core10in the axial direction is 32 mm. The overhang amount is 7 mm. The outer diameter of the stator core50is 110 mm, and the inner diameter of the stator core50is 56 mm. Furthermore, the outer diameter of the facing region101of the rotor core10is 54.5 mm, and the outer diameter of a part of the overhang region102, specifically, within a range of 6 mm from the upper end of the rotor core10, is 60 mm. In this case, the inertia of the rotor core10of the first embodiment is equal to the inertia of the rotor core10of the comparative example. The length of the rotor core10of the first embodiment in the axial direction is 32 mm, while the length of the rotor core10of the comparative example in the axial direction is 35 mm. The inertia equal to that of the comparative example can be obtained while shortening the length of the rotor core in the axial direction by 8.5%. Further, the amount of the magnetic flux of the permanent magnets3in the overhang region102of the rotor core10interlinked with the coils55of the first embodiment increases by 8% as compared to that of the comparative example. Thus, in the first embodiment, the rotation of the rotor1can be stabilized by increasing the inertia while shortening the length of the rotor core10in the axial direction, and the motor efficiency can be improved by increasing the amount of the magnetic flux of the permanent magnets3interlinked with the coils55. If the outer diameter of the overhang region102of the rotor core10is simply increased, the minimum width of the thin wall portion20between the outer circumference of the rotor core and the opening12increases, and thus the short-circuit magnetic flux between adjacent magnetic poles cannot be sufficiently reduced and the motor efficiency decreases. In the first embodiment, the minimum width W of the thin wall portion20of the rotor core10is the same in the facing region101and in the overhang region102, and thus the short-circuit magnetic flux between adjacent magnetic poles can be suppressed. Thus, the motor efficiency can be improved. The rotor core10is formed by stacking the stamped steel laminations. Each steel lamination in the overhang region102of the rotor core10differs from the steel lamination in the facing region101only in the shape of the outer circumference portions16(FIG.4(A)). Thus, when the steel lamination for the overhang region102of the rotor core10is stamped, the same blades as those used to stamp the steel lamination for the facing region101can be used, except for blades to stamp the outer circumference portions16. Thus, the productivity can be improved. A magnetic attractive force acts between the rotor core10and the stator core50to attract the rotor core10toward the center of the stator core50in the axial direction. Since the rotor core10protrudes on the opposite side to the compression mechanism portion301, the magnetic attractive force is applied to the rotor core10in a direction to bias the rotor core10against the compression mechanism portion301. Thus, the rotation of the rotor1can be further stabilized against the load pulsation of the compression mechanism portion301. In the above description, the region in a range of 6 mm from the upper end of the overhang region102has the larger outer diameter. That is, it is not necessary that the entire overhang region102has the larger outer diameter. It is sufficient that the outer diameter of at least a part of the overhang region102is larger than the outer diameter of the facing region101. InFIGS.4(A) and4(B), each thin wall portion20has the constant width, but the width of the thin wall portion20is not necessarily constant. For example, as illustrated inFIG.7(A), the thin wall portion20may have a plurality of widths W1and W2. In this case, the narrowest width of these widths corresponds to the minimum width W described above. InFIG.4(A), each outer circumference portion17has a width in the circumferential direction equal to an interval between two openings12on both sides of the magnet insertion hole11. However, for example, as illustrated inFIG.7(A), the outer circumference portion17may be formed longer than the outer circumference portion17shown inFIG.4(A). Conversely, as illustrated inFIG.7(B), the outer circumference portion17may be formed shorter than the outer circumference portion17shown inFIG.4(A). The outer circumference of the facing region101of the rotor core10has a circular shape inFIG.4(B), but may have other shapes. For example, the outer circumference may have a flower circle shape whose outer diameter is maximum at the pole centers and is minimum at the inter-pole portions. Effects of Embodiment As described above, in the first embodiment, the rotor core10has the facing region101where the rotor core faces the stator core50and the overhang region102where the rotor core protrudes from the stator core50in the axial direction. The distance from the center axis C1to a portion of the outer circumference of the rotor core10located on the outer side of the magnet insertion hole11in the radial direction is longer in at least a part of the overhang region102than in the facing region101. The minimum width W of the thin wall portion20in the radial direction is the same in the facing region101and in the overhang region102. Thus, the inertia can be increased while shortening the length of the rotor core10in the axial direction. Accordingly, the rotation of the rotor1can be stabilized against the load pulsation of the compression mechanism portion301, and vibration and noise can be suppressed. Furthermore, the amount of magnetic flux of the permanent magnets3interlinked with the coils55is increased, and the short-circuit magnetic flux is suppressed by the thin wall portion20, so that the motor efficiency can be improved. As a result, the rotation of the rotor1can be stabilized, the motor efficiency can be improved, and the small-sized and highly-reliable motor100can be obtained. In at least a part of the overhang region102of the rotor core10, the outer circumference portion17located on the outer side in the radial direction of the magnet insertion hole11protrudes outward in the radial direction with respect to the outer circumference portion16located on the outer side in the radial direction of the opening12. Thus, the inertia can be increased and the short-circuit magnetic flux can be suppressed with a simple configuration. Second Embodiment FIG.8is a longitudinal sectional view illustrating a compressor300A of a second embodiment.FIG.9is a longitudinal sectional view illustrating a motor100A, of the compressor300A of the second embodiment. In the second embodiment, the sheet thickness of each of the steel laminations constituting the rotor core10of a rotor1A differs between the facing region101and the overhang region102. More specifically, as illustrated inFIG.9, the sheet thickness T2of the steel lamination in the overhang region102of the rotor core10is thicker than the sheet thickness T1of the steel lamination in the facing region101of the rotor core10. The cross-sectional shapes of the overhang region102and the facing region101of the rotor core10are as described in the first embodiment with reference toFIGS.4(A) and4(B). As the thickness of the steel laminations decreases, the number of steel laminations, i.e., the stacking number, constituting the stacking body having the same length in the axial direction increases. Gaps are formed between the steel laminations in the axial direction. Thus, assuming that the length of the stacking body in the axial length is the same, as the stacking number increases, the proportion of the gaps increases, and the weight of the stacking body decreases. Therefore, in order to increase the inertia, it is desirable to thicken the sheet thickness of the steel lamination. In the facing region101of the rotor core10, the amount of change in the magnetic flux due to the rotating magnetic field of the coils55in the stator5is large. In order to suppress the eddy current loss caused by the change in the magnetic flux, it is desirable that the sheet thickness of each steel lamination is thin. In contrast, in the overhang region102of the rotor core10, the amount of change in the magnetic flux is smaller than in the facing region101, so that the eddy current loss is less likely to occur even when the sheet thickness of the steel laminations is thickened. For this reason, in the second embodiment, the sheet thickness T2of the steel lamination in the overhang region102of the rotor core10is made thicker than the sheet thickness T1of the steel lamination in the facing region101of the rotor core10. Thus, the inertia of the rotor core10can be increased while suppressing an increase in the eddy current loss. Due to the above-described relationship between the sheet thicknesses T1and T2, the weight per unit length of the rotor core10in the axial direction is greater in the overhang region102than in the facing region101. That is, the inertia per unit length of the rotor core10in the axial direction is greater in the overhang region102than in the facing region101. In this regard, it is not necessary that the sheet thickness of each of all the steel laminations in the overhang region102of the rotor core10is thicker than the sheet thickness of the steel lamination in the facing region. It is sufficient that the sheet thickness of at least one steel lamination in the overhang region102is thicker than the sheet thickness T1of the steel lamination in the facing region101. The motor100A and the compressor300A of the second embodiment are configured in the same manner as the motor100and the compressor300of the first embodiment except for the points described above. As described above, in the second embodiment, the sheet thickness T2of the steel lamination in at least a part of the overhang region102of the rotor core10is thicker than the sheet thickness T1of the steel lamination in the facing region101of the rotor core10. Thus, the inertia of the rotor core10can be increased while suppressing an increase in the eddy current loss. That is, the rotation of the rotor1A can be stabilized, and the motor efficiency can be improved. Third Embodiment FIG.10(A)is a sectional view of the overhang region102of a rotor1B of a motor of a third embodiment, andFIG.10(B)is a sectional view of the facing region101of the motor of the third embodiment. In the third embodiment, the number of slits in the rotor core10of the rotor1B differs between the facing region101and the overhang region102. More specifically, as illustrated inFIG.10(B), five slits13, the number of which is defined as a first number, are formed between the magnetic insertion hole11and the outer circumference15in the facing region101of the rotor core10. Meanwhile, as illustrated inFIG.10(A), no slit13is formed between the magnetic insertion hole11and the outer circumference15in the overhang region102of the rotor core10. In other words, zero slit13, the number of which is defined as a second number, is formed between the magnetic insertion hole11and the outer circumference15in the overhang region102of the rotor core10. In the facing region101of the rotor core10, the amount of change in the magnetic flux due to the rotating magnetic field of the coils55of the stator5is large, which may cause iron loss in the rotor core10or may cause vibration and noise due to the magnetic attractive force. In contrast, in the overhang region102of the rotor core10, the amount of change in the magnetic flux is smaller than in the facing region101, so that iron loss or vibration and noise due to the magnetic attractive force is less likely to occur as compared to in the facing region101. Thus, in the third embodiment, the slits13are provided in the facing region101of the rotor core10, while no slit13is provided in the overhang region102, or the number of slits13is made smaller in the overhang region102than in the facing region101. By decreasing the number of slits13, the weight of the rotor core10can be increased, and the inertia of the rotor core10can be increased. The number of slits13in the overhang region102of the rotor core10is made smaller than the number of slits13in the facing region101in this example. However, it is sufficient that the number of holes in the overhang region102of the rotor core10is smaller than the number of holes in the facing region101, and such holes are not limited to the slits13. It is not necessary that the number of holes in each of all the steel laminations in the overhang region102of the rotor core10is smaller than the number of holes in the steel lamination in the facing region101. It is sufficient that the number of holes in at least one steel lamination in the overhang region102is smaller than the number of holes in the steel lamination in the facing region101. The motor and the compressor of the third embodiment are configured in the same manner as the motor100and the compressor300of the first embodiment except for the points described above. As described above, in the third embodiment, the facing region101of the rotor core10has the slits13, while at least a part of the overhang region102has no slit13or fewer slits13than the slits13in the facing region101. Therefore, the inertia can be increased without impairing the performance of the motor100. That is, the rotation of the rotor1B can be stabilized, and the motor efficiency can be improved. The configuration described in the second embodiment may be applied to the third embodiment. Fourth Embodiment FIG.11(A)is a sectional view of the overhang region102of a rotor1C of a motor of a fourth embodiment, andFIG.11(B)is a sectional view of the facing region101of the motor of the fourth embodiment. In the fourth embodiment, the shape of the opening12in the rotor1C differs between the facing region101and the overhang region102. More specifically, the openings22in the overhang region102of the rotor core10illustrated inFIG.11(A)are formed to be elongated outward in the radial direction with respect to the openings12in the facing region101of the rotor core10illustrated inFIG.11(B). In other words, the opening22illustrated inFIG.11(A)is formed to protrude outward in the radial direction with respect to the opening12illustrated inFIG.11(B). An outer circumference25of the overhang region102of the rotor core10illustrated inFIG.11(A)is formed to have a circular shape, which is similar to the outer circumference15of the facing region101of the rotor core10illustrated inFIG.11(B). A distance R2from the center axis C1to the outer circumference25is longer than the distance R1from the center axis C1to the outer circumference15. In the fourth embodiment, even when the outer circumference25of the overhang region102of the rotor core10has a circular shape, the minimum width W of the thin wall portion20between the opening22and the outer circumference25in the overhang region102can be made equal to the minimum width W of the thin wall portion20between the opening12and the outer circumference15in the facing region101. It is not necessary that the openings22of all the steel laminations in the overhang region102of the rotor core10protrude outward in the radial direction. It is sufficient that the openings22of at least one steel lamination in the overhang region102protrude outward in the radial direction. The outer circumference of each of the facing region101and the overhang region102of the rotor core10is not limited to a circular shape, but may be, for example, a flower circle shape whose outer diameter is maximum at the pole centers and is minimum at the inter-pole portions. The motor and the compressor of the fourth embodiment are configured in the same manner as the motor100and the compressor300of the first embodiment except for the points described above. As described above, in the fourth embodiment, the opening22in at least a part of the overhang region102of the rotor core10protrudes outward in the radial direction with respect to the opening12in the facing region101of the rotor core10, and thus the minimum width W of the thin wall portion20can be made the same in the facing region101and in the overhang region102, even when the outer circumferences of the facing region101and the overhang region102of the rotor core10have circular shapes. This makes it possible to stabilize the rotation of the rotor core10against the load pulsation of the compression mechanism portion301and to suppress the short-circuit magnetic flux between adjacent magnetic poles, as in the first embodiment. That is, the rotation of the rotor1C can be stabilized, and the motor efficiency can be improved. The configuration described in the second embodiment or the third embodiment may be applied to the fourth embodiment. Fifth Embodiment FIG.12is a longitudinal sectional view illustrating a compressor300D of a fifth embodiment. In the fifth embodiment, the rotor core10of a rotor1D has two-staged overhang regions102and103. More specifically, as illustrated inFIG.12, the rotor core10has a first overhang region102that protrudes from the stator core50on the opposite side to the compression mechanism portion301, and a second overhang region103that protrudes from the first overhang region102. FIG.13(A)is a sectional view of the second overhang region103,FIG.13(B)is a sectional view of the first overhang region102, andFIG.13(C)is a sectional view of the facing region101, in the rotor1D of a motor100D of the fifth embodiment. As illustrated inFIG.13(A), an outer circumference portion27located on the outer side in the radial direction of each magnet insertion hole11in the second overhang region103of the rotor core10is located on the outer side in the radial direction with respect to the outer circumference portion17in the first overhang region102illustrated inFIG.13(B). The cross-sectional shape of the first overhang region102of the rotor core10illustrated inFIG.13(B)is as described in the first embodiment with reference toFIG.4(A). The cross-sectional shape of the facing region101of the rotor core10illustrated inFIG.13(C)is as described in the first embodiment with reference toFIG.4(B). That is, a distance R3(FIG.13(A)) from the center axis C1to the outer circumference portion27in the second overhang region103of the rotor core10is longer than the distance R2(FIG.13(B)) from the center axis C1to the outer circumference portion17in the first overhang region102of the rotor core10, and longer than the distance R1(FIG.13(C)) from the center axis C1to the outer circumference15in the facing region101of the rotor core10. An outer circumference portion26located on the outer side in the radial direction of the thin wall portion20in the second overhang region103of the rotor core10is located at the same position in the radial direction as the outer circumference15in the facing region101and the outer circumference portion16in the first overhang region102. That is, the minimum width W of the thin wall portion20is the same in the facing region101, in the first overhang region102, and in the second overhang region103. In the fifth embodiment, since the rotor core10has two-staged overhang regions102and103, the inertia of the rotor core10is further increased. The minimum width W of the thin wall portion20of the rotor core10is the same in the facing region101, in the overhang region102, and in the overhang region103, and thus the short-circuit magnetic flux between adjacent magnetic poles can be suppressed. The motor and the compressor of the fifth embodiment are configured in the same manner as the motor100and the compressor300of the first embodiment except for the points described above. As described above, in the fifth embodiment, since the rotor core10has the two-stage overhang regions102and103, the inertia of the rotor core10can be further increased, thereby further stabilizing the rotation of the rotor1D, and suppressing vibration and noise. The minimum width W of the thin wall portion20is the same in the facing region101, in the overhang region102, and in the overhang region103, and thus the short-circuit magnetic flux between adjacent magnetic poles can be suppressed. That is, the rotation of the rotor1D can be stabilized, and the motor efficiency can be improved. Although the case where the rotor core10has the two-staged overhang regions102and103has been described, the rotor core may have three or more stages of overhang regions. The configuration described in the second embodiment, the third embodiment, or the fourth embodiment may be applied to the fifth embodiment. Sixth Embodiment FIG.14is a longitudinal sectional view illustrating a compressor300E of a sixth embodiment. In the sixth embodiment, the rotor core10of a rotor1E has the overhang region102on each of both sides of the facing region101in the axial direction. More specifically, as illustrated inFIG.14, the rotor core10has the overhang region102that protrudes from the stator core50on the opposite side to the compression mechanism portion301, and another overhang region102that protrudes from the stator core50toward the compression mechanism portion301. The cross-sectional shape of each overhang region102of the rotor core10is as described in the first embodiment with reference toFIG.4(A). The cross-sectional shape of the facing region101of the rotor core10is as described in the first embodiment with reference toFIG.4(B). In the sixth embodiment, since the rotor core10has the overhang region102on each of both sides in the axial direction, the inertia of the rotor core10is further increased. The minimum width W of the thin wall portion20in the rotor core10is the same in the facing region101and in each overhang region102, and thus the short-circuit magnetic flux between adjacent magnetic poles can be suppressed. The motor and the compressor of the sixth embodiment are configured in the same manner as the motor100and the compressor300of the first embodiment except for the points described above. As described above, in the sixth embodiment, since the rotor core10has the overhang region102on each of both sides in the axial direction, the inertia of the rotor core10can be further increased, thereby further stabilizing the rotation of the rotor1E, and suppressing vibration and noise. The minimum width W of the thin wall portion20of the rotor core10is the same in the facing region101and in each overhang region102, and thus the short-circuit magnetic flux between adjacent magnetic poles can be suppressed, and the motor efficiency can be improved. The above-described configuration in which the overhang region is provided on each of both sides of the rotor core10in the axial direction can be applied to each of the second to fifth embodiments. Control System Next, a control system for the motor100of each of the first to sixth embodiments will be described.FIG.15is a block diagram illustrating the control system for the motor100. A drive circuit200that controls the motor100includes a rectifier circuit202that converts an AC voltage supplied from a commercial AC power supply201into a DC voltage, an inverter203that converts the DC voltage output from the rectifier circuit202into an AC voltage and supplies the AC voltage to the motor100, and a main element drive circuit204that drives the inverter203. The drive circuit200also includes a voltage detector206that detects the DC voltage output from the rectifier circuit202, a rotating position detector208that detects a terminal voltage of the motor100to thereby detect a position of the rotor of the motor100, and a controller205that calculates an optimum output voltage of the inverter203and outputs a pulse width modulation (PWM) signal to the main element drive circuit204based on the result of calculation. Two voltage dividing resistors connected in series are provided between the rectifier circuit202and the inverter203. The voltage detector206samples and holds an electrical signal obtained by lowering the high DC voltage using a voltage divider circuit formed of these voltage dividing resistors. The AC power supplied from the inverter203is supplied to the coils55of the motor100through the terminals311of the compressor300(FIG.12), so that the rotor1rotates by the rotating magnetic field. The rotating position detector208detects the rotating position of the rotor1and outputs the position information to the controller205. The controller205calculates an optimum output voltage of the inverter203to be supplied to the motor100, based on the position information of the rotor1and based on a target rotation speed command or information on operating conditions of the apparatus, sent from outside the drive circuit200. Then, the controller205outputs the calculated output voltage to the main element drive circuit204. Switches of the inverter203are switched by the main element drive circuit204. Variable speed drive of the motor100is performed under PWM control by the inverter203of the drive circuit200. Instead of the motor100of the first embodiment, the motors of the second to sixth embodiments may be used. When control is performed using the inverter203, the control against load pulsation is generally difficult. However, using the motor of each of the above described embodiments makes it possible to stably drive the motor against the load pulsation of the compression mechanism portion301. Air Conditioner Next, an air conditioner400(also referred to as a refrigeration air conditioning apparatus) to which the compressor300of each embodiment is applicable will be described.FIG.16is a diagram illustrating a configuration of the air conditioner400. The air conditioner400includes the compressor300of the first embodiment, a four-way valve401as a switching valve, a condenser402to condense refrigerant, a decompressor403to reduce the pressure of the refrigerant, an evaporator404to evaporate the refrigerant, and a refrigerant pipe410to connect these components. The compressor300, the condenser402, the decompressor403, and the evaporator404are connected together by the refrigerant pipe410to constitute a refrigerant circuit. The compressor300includes an outdoor fan405facing the condenser402and an indoor fan406facing the evaporator404. The operation of the air conditioner400is as follows. The compressor300compresses sucked refrigerant and sends out the compressed refrigerant as high-temperature and high-pressure refrigerant gas. The four-way valve401is provided for switching a flow direction of the refrigerant. During a cooling operation, the four-way valve401causes the refrigerant sent from the compressor300to flow into the condenser402as illustrated inFIG.16. The condenser402exchanges heat between the refrigerant sent from the compressor300and the outdoor air sent by the outdoor fan405to condense the refrigerant and sends out the condensed refrigerant as liquid refrigerant. The decompressor403expands the liquid refrigerant sent from the condenser402and then sends out the expanded refrigerant as low-temperature and low-pressure liquid refrigerant. The evaporator404exchanges heat between the low-temperature and low-pressure liquid refrigerant sent from the decompressor403and indoor air to evaporate (vaporize) the refrigerant, and sends out the evaporated refrigerant as refrigerant gas. Thus, air deprived of heat in the evaporator404is supplied by the indoor fan406to the interior of a room, which is a space to be air-conditioned. During a heating operation, the four-way valve401causes the refrigerant sent from the compressor300to flow into the evaporator404. In this case, the evaporator404functions as a condenser, and the condenser402functions as an evaporator. The compressor300of the air conditioner400suppresses vibration and noise and has high operating efficiency, as described in the first embodiment. Thus, quietness of the air conditioner400can be improved, and an operation efficiency of the air conditioner400can be improved. Instead of the compressor of the first embodiment, the compressor of each of the second to sixth embodiments may be used. Any components of the air conditioner400other than the compressor300are not limited to the configuration examples described above. Although the desirable embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications or changes can be made to those embodiments without departing from the scope of the present invention. | 53,062 |
11863021 | DETAILED DESCRIPTION Hereinafter, implementations the present disclosure will be described in detail with reference to the accompanying drawings. As described above, a hermetic compressor in which an electric motor constituting a motor unit is installed in a shell together with a compression unit can be divided into a rotary (or rotating) motor or reciprocating motor according to operation of a rotor. Herein, a connection-type reciprocating compressor in which a rotating shaft (or crankshaft) is connected to a piston, among hermetic compressors to which a rotatory motor is applied, will be used as a representative example. However, it is not limited to the connection-type reciprocating compressor, and can also be employed in an electric motor configured as a rotary motor and a hermetic compressor having the same. FIG.1is a see-through perspective view illustrating an example of a shell of an example of a reciprocating compressor, andFIG.2is a cross-sectional view illustrating an example of an inside of the reciprocating compressor ofFIG.1. In some implementations, as illustrated inFIGS.1and2, a reciprocating compressor can include a shell110that defines an outer appearance, an electric motor (or motor unit)120that is provided at an inner space110aof the shell110and provides a driving force, a compression unit140that compresses a refrigerant by receiving the driving force from the electric motor120, a suction and discharge part150that guides a refrigerant to a compression chamber and discharges a compressed refrigerant, and a support part160that supports a compressor body C including the electric motor120and the compression unit140with respect to the shell110. In some examples, the shell110can include a lower shell111and an upper shell112. For example, the lower shell111and the upper shell112can be coupled to each other and define a hermetically sealed inner space110a. The electric motor120and the compression unit140are accommodated in the inner space110aof the shell110. The shell110is made of an aluminum alloy (hereinafter, abbreviated as “aluminum”) that is lightweight and has a high thermal conductivity. In some examples, the lower shell111can have a substantially hemisphere shape. A suction pipe115, a discharge pipe116, and a process pipe are coupled to the lower shell111in a penetrating manner. The suction pipe115, the discharge pipe116, and the process pipe can be coupled to the lower shell111by insert die casting. The upper shell112has a substantially hemispherical shape like the lower shell111. The upper shell112is coupled from above to the lower shell111to thereby define the inner space110aof the shell110. The upper shell112and the lower shell111can be coupled by welding. In some implementations, the upper shell112and the lower shell111can be coupled by a bolt when they are made of an aluminum material that is not suitable for welding. A description will now be given of the electric motor that defines the motor unit. As illustrated inFIGS.1and2, the electric motor120includes a stator121and a rotor122. The stator121is elastically supported with respect to the inner space110aof the shell110, namely, a bottom surface of the lower shell111, and the rotor122is rotatably installed inside the stator121. The stator121includes a stator core1211and a stator coil1212. The stator core1211is made of a metal material, such as an electrical steel sheet, and performs electromagnetic interaction with the stator coil1212and the rotor122described hereinafter through an electromagnetic force when a voltage is applied to the electric motor120from the outside. The stator core1211has a substantially rectangular cylinder shape. For example, an inner circumferential surface of the stator core1211can be formed in a circular shape, and an outer circumferential surface thereof can be formed in a rectangular shape. The stator core1211is fixed to a lower surface of a main bearing141by a stator coupling bolt. A lower end of the stator core1211is supported with respect to a bottom surface of the shell110by a support spring161to be described hereinafter in a state that the stator core1211is axially and radially spaced apart from an inner surface of the shell110. This can reduce or prevent vibration generated during operation from being directly transferred to the shell110. The stator coil1212is wound inside the stator core1211. When a voltage is applied from the outside, the stator coil1212generates an electromagnetic force to perform electromagnetic interaction with the stator core1211and the rotor122. This can allow the electric motor120to generate a driving force that causes the compression unit140to perform a reciprocating motion. In some examples, an insulator1213can be disposed between the stator core1211and the stator coil1212. This can help to prevent direct contact between the stator core1211and the stator coil1212to thereby facilitate the electromagnetic interaction. The rotor122includes a rotor core1221, permeant magnets1222, a connection part1231, and an inertial core1232. The rotor core1221, like the stator core1211, can be made of a metal material such as an electrical steel plate, and a shaft hole1221ato which a rotating shaft130defining a motor shaft is press-fitted and coupled can be formed at a center of the rotor core1221. The shaft hole1221acan be formed through the rotor core1221in an axial direction, such that the rotor core1221has a cylindrical shape. As for the connection type reciprocating compressor, a motor shaft is usually referred to as a crank shaft. However, since the electric motor according to the present disclosure is not necessarily limited to the connection type reciprocating compressor, the motor shaft will be hereinafter referred to as a rotating shaft. The rotating shaft130includes a main shaft portion131and an eccentric shaft portion133provided at opposite ends of a plate portion132in the axial direction. A connecting rod143defining a portion of the compression unit140to be described hereinafter is rotatably coupled to the eccentric shaft portion133, and a piston142defining a portion of the compression unit140to be described hereinafter can be coupled to an end of the connecting rod143. Accordingly, when a voltage is applied to the rotor122, the rotating shaft130rotates together with the rotor122to thereby transmit a rotational force of the electric motor120to the compression unit140. A magnet mounting hole1221bin which the permanent magnet1222is inserted can be formed through an edge of the rotor core1221in the axial direction. The magnet mounting hole1221bcan be provided in plurality to be disposed at predetermined intervals in a circumferential direction. A plurality of magnet mounting holes1221bcan be formed with respect to the shaft hole1221a. In some examples, the magnet mounting hole1221bcan be formed through both ends or a portion of the rotor core1221in the axial direction according to a shape of the rotor core1221. For example, when the rotor core1221is formed in a single shape and is disposed inside the stator core1211, the magnet mounting hole1221bcan be formed through the both ends of the rotor core1221in the axial direction. However, when the rotor core1221is formed in a two-stage shape and a portion of the rotor core1221is disposed at an outside of the stator core1211, the magnet mounting hole1221bcan be formed only at the rotor core1221located at an inside of the stator core1211. The rotor core1221will be described later together with the connection part1231and the inertial core1232. The permanent magnets1222can be inserted into the respective magnet mounting holes1221bat equal intervals in a circumferential direction of the rotor core1221. The permanent magnets1222can each have a rectangular cross-sectional shape to be elongated in the axial direction. An axial length of the permanent magnet1222can be substantially the same as an axial length of the rotor core1221. Accordingly, once the permanent magnet1222is inserted into the magnet mounting hole1221bof the rotor core1221, the permanent magnet1222is not separated therefrom due to the connection part1231to be described hereinafter. The permanent magnet1222will be described later together with the connection part1231and the inertial core1232. Hereinafter, the compression unit will be described. As illustrated inFIGS.1and2, the compression unit140includes the main bearing141and the piston142. The main bearing141is elastically supported on the shell110, and the piston142is coupled to the rotating shaft130by the connecting rod143to perform a relative motion with respect to the main bearing141. The main bearing141is provided at an upper side of the electric motor120. The main bearing141includes a frame1411(or frame portion), a fixing protrusion1412coupled to the stator121of the electric motor120, a bearing portion1413(or shaft receiving portion) that supports the rotating shaft130, and a cylinder unit (cylinder)1415that defines a compression chamber141a. The frame1411can have a flat plate shape extending in a horizontal direction, or a radial plate shape by processing a portion of an edge excluding corners to reduce weight or thickness. The fixing protrusion1412is provided at an edge of the frame1411. For example, the fixing protrusion1412can protrude from the edge of the frame1411toward the electric motor120, namely, in a downward direction. The main bearing141and the stator121can be coupled by a stator coupling bolt to be elastically supported on the lower shell111together with the stator121of the electric motor120. The bearing portion1413can axially extend from a central portion of the frame1411in opposite directions. A bearing hole1413acan be axially formed through the bearing portion1413so as to allow the rotating shaft130to penetrate therethrough, and a bush bearing can be insertedly coupled to an inner circumferential surface of the bearing hole1413a. The plate portion132of the rotating shaft130can be supported on an upper end of the bearing portion1413in the axial direction, and the main shaft portion131of the rotating shaft130can be supported on an inner circumferential surface of the bearing portion1413in a radial direction. Accordingly, the rotating shaft130can be axially and radially supported by the main bearing141. The cylinder unit (hereinafter, abbreviated as “cylinder”)1415is radially eccentric from an edge of one side of the frame1411. The cylinder1415is formed through the main bearing141in the radial direction so that the piston142connected to the connecting rod143is inserted into an inner open end thereof, and a valve assembly151defining the suction and discharge part150to be described hereinafter is inserted into an outer open end thereof. The piston142is configured such that a side (a rear side) that faces the connecting rod143is open and an opposite side thereof, namely, a front side is closed. Accordingly, the connecting rod143is inserted into the rear side of the piston142to be rotatably coupled, and the front side of the piston142is formed in a closed shape to define the compression chamber141ainside the cylinder1415together with the valve assembly151to be described hereinafter. In some implementations, the piston142can be made of the same material as the main bearing141, such as an aluminum alloy. This can help to prevent a magnetic flux from being transmitted to the piston142from the rotor122. As the piston142is made of the same material as the main bearing141, the piston142and the main bearing141(more precisely, the cylinder) can have the same coefficient of thermal expansion. Accordingly, even when the inner space110aof the shell110is in high temperature condition (approximately 100° C.) during operation of the compressor, interference between the main bearing141and the piston142, caused by thermal expansion, can be suppressed or reduced. Hereinafter, the suction and discharge part will be described. Referring back toFIGS.1and2, the suction and discharge part150includes the valve assembly151, a suction muffler152, and a discharge muffler153. The valve assembly151and the suction muffler152are sequentially coupled from the outer open end of the cylinder1415. The valve assembly151includes a valve plate1511, a suction valve1512, a discharge valve1513, a valve stopper1514, and a discharge cover1515. The valve plate1511has a substantially rectangular plate shape and is installed to cover a front-end surface of the main bearing141, namely, a front open surface of the compression chamber141a. For example, a coupling hole is provided at each corner of the valve plate1511, so as to be coupled to a coupling groove formed on the front-end surface of the main bearing141by a bolt. In some implementations, one suction port1511aand at least one discharge port1511bcan be defined in the valve plate1511. When a plurality of discharge ports1511bare provided, the suction port1511acan be formed at a central portion of the valve plate1511, and the plurality of discharge ports1511bcan be formed along a circumference of the suction port1511ato be spaced apart by predetermined intervals or gaps. The suction valve1512can be disposed at a side facing the piston142based on the valve plate1511. Accordingly, the suction valve1512can be bent in a direction toward the piston142to be opened and closed. The discharge valve1513can be disposed at an opposite side of the piston142based on the valve plate1511. Accordingly, the discharge valve1513can be bent in a direction opposite to the piston142to be opened and closed. The valve stopper1514can be disposed between the valve plate1511and the discharge cover1515with the discharge valve1513interposed therebetween. The valve stopper1514is fixed by being pressed by the discharge cover1515in a state that one end thereof is in contact with a fixing portion of the discharge valve1513. The discharge cover1515can be coupled to the front-end surface of the main bearing141with the valve plate1511interposed therebetween, allowing the compression chamber141ato be finally covered by the discharge cover1515. Therefore, the discharge cover1515can also be referred to as a “cylinder cover”. The suction muffler152can be fixed by the valve assembly151to communicate with the suction port1511aof the valve plate1511. Accordingly, the suction muffler152transfers a refrigerant suctioned through the suction pipe115to the compression chamber141aof the cylinder1415. The suction muffler152is provided therein with a suction space portion. An inlet (or entrance) of the suction space portion communicates with the suction pipe115in a direct or indirect manner, and an outlet (or exit) of the suction space portion directly communicates with a suction side of the valve assembly151. The discharge muffler153can be installed separately from the main bearing141. The discharge muffler153is provided therein with a discharge space portion. An inlet of the discharge space portion can be connected to a discharge side of the valve assembly151by a loop pipe118, and an outlet of the discharge space portion can be directly connected to the discharge pipe116by the loop pipe118. Hereinafter, the support part will be described. In some implementations, as illustrated inFIGS.1and2, the support parts160can support between a lower surface of the electric motor120and the bottom surface of the lower shell111that faces the lower surface the electric motor120, which, for example, support four corners of the electric motor120with respect to the shell110. For example, each of the support parts160can include a support spring161, a first spring cap162that supports a lower end of the support spring161, and a second spring cap163. In other words, each support part160defines one unitary support assembly made up of the support spring161, the first spring cap162, and the second spring cap163, and the unitary support assemblies can be installed along a periphery of the compressor body at predetermined intervals. The support spring161is configured as a compression coil spring. The first spring cap162is fixed to the bottom surface of the lower shell111to support the lower end of the support spring161, and the second spring cap163is fixed to a lower end of the electric motor120to support an upper end of the support spring161. Accordingly, the support springs161are supported by the respective first spring caps162and the respective second spring caps163, so as to elastically support the compressor body C with respect to the shell110. In the drawings, an unexplained reference numeral110bdenotes an oil storage space. The reciprocating compressor described above can operate as follows. That is, when power is applied to the electric motor120, the rotor122rotates. When the rotor122rotates, the rotating shaft130coupled to the rotor122rotates together, causing a rotational force to be transferred to the piston142through the connecting rod143. The connecting rod143allows the piston142to perform a reciprocating motion in a front and rear direction (or back and forth) with respect to the cylinder1415. In detail, when the piston142moves backward from the cylinder1415, volume of the compression chamber141aincreases. When the volume of the compression chamber141ais increased, a refrigerant filled in the suction muffler152passes through the suction valve1512of the valve assembly151, and is then suctioned into the compression chamber141aof the cylinder1415. In contrast, when the piston142moves forward from the cylinder1415, volume of the compression chamber131adecreases. When the volume of the compression chamber141ais decreased, a refrigerant filled in the compression chamber141ais compressed, passes through the discharge valve1513of the valve assembly151, and is then discharged to a discharge chamber1515aof the discharge cover1515. This refrigerant flows into the discharge space portion of the discharge muffler153through the loop pipe118and is then discharged to a refrigeration cycle through the loop pipe118and the discharge pipe116. Such series of processes are repeated. As described above, in the hermetic compressor, both the electric motor defining the motor unit and the compression unit are installed in the shell. When the compressor is reduced in size, a size of the electric motor is also decreased, and a size of the rotor defining a portion of the electric motor is reduced accordingly. A smaller rotor leads to a decrease in rotational inertia, which can be disadvantageous in terms of motor efficiency. In order to help to prevent this, the rotor can be further provided with an inertial core for compensating the decrease of the rotational inertia while achieving the size reduction of the rotor and the compressor. FIG.3is an exploded perspective view illustrating examples of an inertial core and a rotor,FIG.4is a perspective view illustrating an example of a coupled state of the inertial core and the rotor, andFIG.5is a front view ofFIG.4. Referring back toFIG.2, the rotor122can include the rotor core1221and the permanent magnets1222as described above. One shaft hole1221ato which the rotating shaft130is press-fitted can be defined at the center of the rotor core1221, and a plurality of magnet mounting holes1221bin which the respective permanent magnets1222are inserted can be formed at the edge of the rotor core1221. The shaft hole1221aand the magnet mounting holes1221bcan be formed through the rotor core1221in the axial direction, and the plurality of magnet mounting holes1221bcan be formed at the edge of the rotor core1221to be spaced apart by predetermined intervals in the circumferential direction. The shaft hole1221acan have a circular cross-sectional shape to correspond to an outer surface of the rotating shaft130, and the magnet mounting hole1221bcan have a rectangular cross-sectional shape to correspond to an outer surface of the permanent magnet1222. The rotor core1221can be formed by stacking a plurality of thin electrical steel sheets in the axial direction. For example, a first coupling hole1221cis formed through the rotor core1221in the axial direction, and a first coupling member1241, such as a bolt and a rivet, is inserted into the first coupling hole1221cso that the plurality of electrical steel sheets can be stacked together. The first coupling hole1221ccan be provided in plurality to be disposed between the shaft hole1221aand the magnet mounting holes1221bat predetermined intervals in the circumferential direction. In addition, the rotor core1221can be formed by stacking thin electrical steel sheets having the same shape in the axial direction, such that the rotor core1221can have the same shape in the axial direction. Alternatively, the rotor core1221can be formed by stacking thin electrical steel sheets having different shapes, such that the rotor core1221can have different shapes in the axial direction. For example, the rotor core1221can be formed in a shape having one outer diameter, or a shape having a plurality of outer diameters in the axial direction. The former can be referred to as a “single-stage rotor core” and the latter can be referred to as a “multi-stage rotor core.” In some implementations, the single-stage rotor core is used as a representative example, but the basic structure can be equally applied to the multi-stage rotor core. Hereinafter, the rotor core can be understood as the single-stage rotor core unless otherwise specified. In some implementations, the inertial core1232can be provided at one end of the rotor122in the axial direction, more precisely, at one end of the rotor core1221in the axial direction. In detail, the inertial core1232can be installed at an upper or lower end of the rotor core1221, or both the upper and lower ends of the rotor core1221according to the shape of a compressor in which the electric motor120is installed. Herein, an example in which the inertial core1232is installed at the upper end of the rotor core1221will be described. Referring toFIGS.3to5, the inertial core1232can be coupled to the upper end of the rotor core1221with the connection part1231interposed therebetween. The connection part1231is a part that is coupled to the rotor core1221, and the inertial core1232is a part that is spaced apart from the rotor core1221. A horizontal cross-sectional area at a middle height (or point) of the connection part1231in the axial direction can be smaller than a horizontal cross-sectional area at a middle height of the rotor core1221in the axial direction, and a horizontal cross-sectional area at a middle height of the inertial core1232in the axial direction can be larger than the horizontal cross-sectional area at the middle height of the rotor core1221in the axial direction. Accordingly, an amount of use of the connection part1231can be reduced, a contact area between the connection part1231and the permanent magnets1222can be reduced, and a fluid flow path F to be described hereinafter can be provided in the connection part1231by providing communication between the inside and the outside of the connection part1231or reducing the horizontal cross-sectional area. The connection part1231and the inertial core1232can be formed as a single body, or separately formed and assembled together. When the connection part1231and the inertial core1232are formed as a single body, it can be advantageous in terms of assemblability, and when the connection part1231and the inertial core1232are separately provided, it can be advantageous in terms of manufacturing cost and magnetic flux leakage reduction. In some implementations, the connection part1231and the inertial core1232can be separately formed, which will be described. In some implementations, the connection part1231and the inertial core1232can be formed as a single body, which will be described later. In some implementations, the connection part1231and the inertial core1232can have the same property or different properties with respect to a magnetic property. When both the connection part1231and the inertial core1232are non-magnetic, it can be suitable for suppressing magnetic flux leakage. On the other hand, when both of the connection part1231and the inertial core1232are magnetic, it can be advantageous in terms of manufacturing costs. In some implementations, the connection part1231can be made of a non-magnetic material, and the inertial core1232can be made of a magnetic material, which will be described. In some implementations, both the connection part1231and the inertial core1232can be made of magnetic materials, which will be described later. FIG.6is an enlarged perspective view illustrating an example of a connection part ofFIG.3,FIG.7is a planar view ofFIG.6, andFIG.8is an enlarged planar view illustrating a portion “A” ofFIG.7. Referring toFIGS.6to8, the connection part1231can be configured as a single body with an annular shape. The connection part1231can be formed in a wavy or zigzag shape along the circumferential direction. For example, the connection part1231can include a plurality of first fixing portions1231a, a plurality of second fixing portions1231b, and a plurality of link portions1231c. The plurality of first fixing portions1231aand the plurality of second fixing portions1231bcan be alternately disposed along the circumferential direction when projected in the axial direction, and the plurality of link portions1231ccan be inclined opposite to each other when projected in the radial direction. Hereinafter, one first fixing portion1231a, one second fixing portion1231b, and one link portion1231cwill be used as representative examples for description. The first fixing portion1231athat is supported on an axial end surface of the rotor core1221(or an end surface of the rotor core1221in the axial direction) can be flat when projected in the radial direction. Accordingly, the first fixing portion1231acan be securely supported on the end surface of the rotor core1221in the axial direction. In detail, the first fixing portion1231acan include a first inner arcuate end portion1231a1, a first outer arcuate end portion1231a2, and a plurality of first linear end portions connecting both ends of the first inner arcuate end portion1231a1and both ends of the first outer arcuate end portion1231a2facing each other. Accordingly, the first fixing portion1231acan have a sectoral shape in which an arc length of its outer circumferential surface is greater (longer) than an arc length of its inner circumferential surface when projected in the axial direction. The first fixing portion1231acan be formed such that a radial center line passes through its circumferential center to pass through a center of the rotating shaft130, namely a center of the rotor122. Accordingly, centrifugal force acting on the first fixing portion1231acan be evenly distributed, allowing the first fixing portion1231ato be securely supported on the rotor core1221. In some implementations, one axial surface (e.g., a lower surface) of the first fixing portion1231acan be formed to correspond to an axial end surface (e.g., an upper surface) of the rotor core1221that faces the first fixing portion1231ain the axial direction. For example, the lower surface of the first fixing portion1231acan be formed flat like the upper surface of the rotor core1221. As a contact area between the connection part1231and the rotor core1221is secured, the connection part1231can be securely supported on the rotor core1221. In addition, the plurality of first fixing portions1231acan have the same arc angle along the circumferential direction. In other words, the plurality of first fixing portions1231acan be disposed at equal intervals in the circumferential direction. This can allow a circumferential support force of the connection part1231to be evenly distributed, and thus, the connection part1231can be securely supported on the rotor core1221. The first fixing portion1231acan be provided at a position where at least a portion or part thereof radially overlaps one axial end (upper end) of the permanent magnet1222. In other words, when the number of permanent magnets1222is greater than the number of first fixing portions1231aas in this implementation, each of the first fixing portions1231acan be disposed over ends of two permanent magnets1222facing each other in the circumferential direction, which can be suitable for fixing the permanent magnets1222. For example, as illustrated inFIG.7, six permanent magnets1222and three first fixing portions1231acan be provided. When a left end in the drawing is referred to as a “first end,” and a right end in the drawing is referred to as a “second end,” one fixing portion1231acan be disposed in a radially overlapping manner over a second end (right end in the drawing) of a first permanent magnet1222aand a first end (left end in the drawing) of a second permanent magnet1222bfacing each other in the circumferential direction. Another first fixing portion1231acan be disposed in a radially overlapping manner over a second end of a third permanent magnet1222cand a first end of a fourth permanent magnet1222dfacing each other in the circumferential direction. The other first fixing portion1231acan be disposed in a radially overlapping manner over a second end of a fifth permanent magnet1222eand a first end of a sixth permanent magnet1222ffacing each other in the circumferential direction. Accordingly, a circumferential center of each of the three first fixing portions1231acan be disposed between two adjacent permanent magnets1222to thereby cover and support the two permanent magnets1222in the axial direction. Thus, one axial ends (upper ends) of the six permanent magnets1222can be covered and supported in the axial direction by the three first fixing portions1231a. In some examples, a second coupling hole1231a4can be defined in a central part of the first fixing portion1231ato be disposed at a position that does not overlap the permanent magnet1222, for example, on the same axis as the first coupling hole1221cof the rotor core1221. Accordingly, the connection part1231can be coupled by the first coupling member1241that passes through the second coupling hole1231a4and the first coupling hole1221c. Referring toFIGS.6to8, the second fixing portion1231b, which is a part supported on the inertial core1232, can be formed flat when projected in the radial direction. Accordingly, the second fixing portion1231bcan be securely supported on the inertial core1232. One axial surface (upper surface) of the second fixing portion1231bfacing the inertial core1232can be formed to correspond to one axial surface (lower surface) of the inertial core1232. For example, the upper surface of the second fixing portion1231bcan be formed flat the same as a lower surface of the inertial core1232. In some examples, a rotation prevention groove in which the second fixing portion1231bis inserted to be supported in the circumferential direction can be formed on the lower surface of the inertial core1232. The second fixing portion1231bcan include a second inner arcuate end portion1231b1, a second outer arcuate end portion1231b2, and a plurality of second linear end portions1231b3connecting both ends of the second inner arcuate end portion1231b1and both ends of the second outer arcuate end portion1231b2. Accordingly, the second fixing portion1231bcan have a sectoral shape in which an arc length of its outer circumferential surface is greater (longer) than an arc length of its inner circumferential surface when projected in the axial direction. An area of the second fixing portion1231bcan be substantially the same as an area of the first fixing portion1231a. Accordingly, the inertial core1232supported on the second fixing portion1231bcan be securely supported. As described above, the second fixing portion1231bcan be formed between two first fixing portions1231aalong the circumferential direction when projected in the axial direction. The plurality of second fixing portions1231bcan be disposed at equal intervals to have the same arc angle in the circumferential direction. Accordingly, a circumferential support force of the connection part1231is evenly distributed to thereby securely support the inertial core1232. A third coupling hole1231b4is formed at each of the second fixing portions1231b. The third coupling hole1231b4can be disposed on the same axis as a fourth coupling hole1232dof the inertial core1232to be described hereinafter. Referring toFIGS.6to8, the link portion1231cis a portion that connects the first fixing portion1231aand the second fixing portion1231b. The plurality of link portions1231ccan be bent opposite to each other along the circumferential direction when projected in the radial direction. For example, when a left end in the drawing is referred to as a “first end,” and a right end in the drawing is referred to as a “second end,” one first link portion1231ccan be bent upward from a second end (left end in the drawing) of one first fixing portion1231alocated on the lower side in the axial direction to a first end (right end in the drawing) of one second fixing portion1231blocated on the upper side in the axial direction, and another link portion1231ccan be bent downward from a second end of the one second fixing portion1231bto a first end of another first fixing portion1231a. Accordingly, the link portions1231ccan be formed in a wavy or zigzag shape in the circumferential direction. Each of the link portions1231ccan be bent at a right angle. For example, one link portion1231ccan be bent at a right angle from a second end of one first fixing portion1231ato be connected to a first end of one second fixing portion1231b, and another link portion1231ccan be bent at a right angle from a second end of the one second fixing portion1231bto be connected to a first end of another first fixing portion1231a. Then, as the first fixing portions1231aand the second fixing portions1231bare arranged continuously in the circumferential direction when projected in the axial direction, support areas of the first fixing portions1231aand the second fixing portions1231bcan be increased and axial support forces of the link portions1231ccan be enhanced when the inertial core1232is coupled to the rotor core1221in the axial direction. In some examples, the link portions1231ccan be obliquely or inclinedly bent in alternatively opposite directions along the circumferential direction. For example, one link portion1231ccan be obliquely bent from a second end of one first fixing portion1231ato be connected to a first end of one second fixing portion1231b, and another link portion1231ccan be obliquely bent from a second end of the one second fixing portion1231bto be connected to a first end of another first fixing portion1231a. As the first fixing portions1231aand the second fixing portions1231bare disposed at predetermined intervals in the circumferential direction when projected in the axial direction, the amount of use of the connection part1231can be reduced accordingly. This is advantageous to reduce manufacturing costs considering that the connection part1231is a relatively expensive non-magnetic material. In some implementations, the link portions1231ccan be bent, curved, or inclined. The link portion1231ccan be formed in an arcuate shape having both side surfaces in the circumferential direction parallel to each other when projected in the axial direction. Accordingly, outer and inner circumference lengths of the link portion1231cthat connects the first fixing portion1231aand the second fixing portion1231bcan be the same, and thus, outer circumferential heights and inner circumferential heights of the first fixing portion1231aand the second fixing portion1231bcan be the same. Referring back toFIG.5, the link portion1231cdefines a gap or distance Δh between the first fixing portion1231aand the second fixing portion1231bas described above. In other words, a slope a of the link portion1231cdetermines an axial height h of the link portion1231c, and the axial height h of the link portion1231cdetermines the distance Δh between the first fixing portion1231aand the second fixing portion1231b. Therefore, the larger the slope a of the link portion1231c, the greater the distance Δh between the first fixing portion1231aand the second fixing portion1231b. This can allow the magnetic inertial core1232to be farther away from the permanent magnet1222inserted into the rotor core1221, which can be suitable for suppressing magnetic flux leakage through the inertial core1232. Thus, the gap Δh between the first fixing portion1231aand the second fixing portion1231bcan also be referred to as an “insulation distance.” More specifically, the slope a of the link portion1231ccan be formed such that the insulation distance (a height of the link portion, a height of the connection part, or a height of the non-magnetic material) Δh between the first fixing portion1231aand the second fixing portion1231bcan be greater than or equal to an axial length (thickness) t of the inertial core1232to be described hereinafter. This is to avoid interference between the inertial core1232that extends more radially outward than an inner circumferential surface of the stator coil1212and the stator coil1212that protrudes from the stator core1211in the axial direction. When the inertial core1232to be described hereinafter is located more inward than the stator coil1212, the insulation distance Δh can be less than a thickness t of the inertial core1232. However, even in this case, an appropriate insulation distance Δh between the inertial core1232and the permanent magnet1222can be provided to suppress magnetic flux leakage. The table below shows the result of an experiment of correlation between no-load back electromotive force (BEMF) and a height (or thickness) of the connection part1231, which is a non-magnetic material.FIG.9is a graph showing this relationship. TABLE 1Height ofBacknon-magneticelectromotiveReduction rate ofmaterial (mm)force (BEMF)BEMF (%)034.4474.3144.0595.0244.9597.0345.7698.7446.0199.3546.0499.3646.1799.6 As shown in the [Table 1] above andFIG.9, it can be seen that a reduction rate of BEMF is about 0.7% when the height of the non-magnetic material is 4 mm, and a reduction rate of BEMF is greatly increased to be approximately 1.3% when the height of the non-magnetic material is 3 mm. Therefore, the height (insulation distance) h of the connection part1231, which is the non-magnetic material, should be less than or equal to the thickness t of the inertial core1232, which is the magnetic material, and should be approximately 4 mm or more in order to suppress magnetic flux leakage. To this end, the slope of the link portion1231ccan be greater than or equal to 20° (degrees) and less than 90° (degrees) with respect to an end surface of the rotor core1221in the axial direction (or an axial end surface of the rotor core1221). As the connection part1231according to the present disclosure is formed by bending a thin plate, the connection part1231can have a horizontal cross-sectional area smaller than a horizontal cross-sectional area of the rotor core1221. In some examples, a fluid flow path F can be provided between the rotor core1221and the inertial core1232as the inside and outside of the connection part1231communicates with each other. Accordingly, a fluid in a periphery of the connection part1231can flow through the fluid flow path F when the rotor122rotates, allowing fluid resistance generated in the periphery of the connection part1231and the inertial core1232to be reduced when the rotor122rotates. As a result, a decrease in efficiency of the motor can be suppressed. As both side surfaces of the link portion1231cin the circumferential direction are parallel to each other when projected in the axial direction, the link portion1231c, as illustrated inFIG.8, can be inclined with respect to the circumferential direction when projected in the axial direction. When the connection part1231rotates together with the rotor122, fluid resistance in the link portion1231ccan be reduced to thereby more effectively suppress a decrease in the motor efficiency. In some implementations, bending line portions1231dcan be formed between the first fixing portion1231aand the link portion1231c, and between the link portion1231cand the second fixing portion1231b, respectively. The bending line portions1231ddefine the first linear end portion1231a3or the second linear end portion1231b3defining both ends of the first fixing portion1231aor the second fixing portion1231b. Accordingly, each of the link portions1231ccan be upwardly or downwardly bent from the first fixing portion1231aor the second fixing portion1231bwith respect to the bending line portion1231ddefining the first fixing portion1231aor the second fixing portion1231b. Referring toFIGS.6and7, the bending line portion1231dcan be provided with a reinforcing rib1231d1to help to prevent a decrease in strength due to stress concentration in the bending line portion1231d. The reinforcing rib1231d1can protrude from a center of the bending line portion1231din a direction in which the link portion1231cis bent, namely, to an inner surface of the bending line portion1231d. This can help to prevent buckling of the relatively thin link portion1231cdue to a coupling force caused when the inertial core1232is coupled to the rotor core1221or deformation of the link portion1231ccaused by centrifugal force generated when the rotor122rotates. Accordingly, rigidity of the bending line portion1231dcan be increased to thereby enhance the reliability of the connection part1231. The reinforcing rib1231d1can pass through the bending line portion1231din the circumferential direction such that its one end is connected to the first fixing portion1231aor the second fixing portion1231band its another end is connected to the link portion1231c. As the connection part1231is formed in a wavy or zigzag shape by pressing a thin plate material, the reinforcing rib1231d1can be formed together while the connection part1231is pressing processed. Accordingly, the reinforcing rib1231d1can be recessed by being pressed from an outer surface to inner surface of the bending line portion1231d. In some examples, this can be achieved when the connection part1231is made of a material having plasticity such as stainless steel, and the reinforcing rib1231d1can be formed in various ways depending on the material of the connection part1231. For example, when the connection part1231has elasticity such as plastic, the outer surface of the bending line portion1231dcan be formed flat and the reinforcing rib1231d1can protrude only to the inner surface of the bending line portion1231d. In some examples, the reinforcing rib1231d1can be provided at the center of the bending line portion1231d, and a length of the reinforcing rib1231d1in a widthwise direction can be approximately less than half of a length of the bending line portion1231din the widthwise direction in consideration of stability, which can be more advantageous in terms of strength. Referring back toFIGS.3to5, the inertial core1232can have an annular shape, and be coupled by being supported on the upper surfaces of the second fixing portions1231bof the connection part1231. The inertial core1232can be made of a magnetic material as described above. For example, the inertial core1232can be made of steel or a similar material. The inertial core1232made of the magnetic material can be inexpensive and have a higher density compared to an inertial core entirely made of a non-magnetic material to thereby increase rotational inertia (moment of inertia) in relation to a cross-sectional area of the inertial core1232. A bearing portion through hole1232bcan be formed through a center of a body portion1232aof the inertial core1232. The bearing portion through hole1232bcan be a hole through which a bearing portion1413of the main bearing141penetrates in the axial direction, and its center can be located on the same axis as a rotation center of the rotating shaft130(a rotation center of the rotor). Accordingly, the body portion1232aof the inertial core1232can produce a uniform centrifugal force along the radial direction when the rotor122rotates. The bearing portion through hole1232bcan be formed in a circular shape having one inner diameter. In some examples, when the connection part1231and the inertial core1232are assembled together before coupling the connection part1231to the rotor core1221, the second coupling hole1231a4of the connection part1231and the first coupling hole1221cof the rotor core1221are covered or blocked by a peripheral portion of the bearing portion through hole1232b. Then, the first coupling member1241cannot be inserted from the inertial core1232into the rotor core1221. In some implementations, coupling member insertion grooves1232ccan extend to be recessed into an inner circumferential surface of the bearing portion through hole1232bin the radial direction. The coupling member insertion groove1232ccan be formed on the same axis as the second coupling hole1231a4of the connection part1231and the first coupling hole1221cof the rotor core1221when projected in the axial direction. Accordingly, when the connection part1231and the inertial core1232are assembled together prior to assembling the connection part1231to the rotor core1221, the first coupling member1241can be inserted from the inertial core1232into the rotor core1221through the coupling member insertion groove1232c. In some examples, the fourth coupling hole1232dcan be formed on the body portion1232aof the inertial core1232. For example, a plurality of fourth coupling holes1232dcan be defined in a periphery of the bearing portion through hole1232bto be spaced apart by predetermined intervals in the circumferential direction. More specifically, the fourth coupling holes1232dcan be formed on the same circumference as the coupling member insertion grooves1232cto be disposed at equal intervals between the coupling member insertion grooves1232cso as not to overlap the coupling member insertion grooves1232c. The fourth coupling hole1232dcan be formed on the same axis as the third coupling hole1231b4such that the connection part1231and the inertial core1232can be coupled by a second coupling member1242passing through the fourth coupling hole1232dand the third coupling hole1231b4. The number of the fourth coupling holes1232dcan correspond to the number of the first coupling holes1221c. In some implementations, the fourth coupling holes1232dof the inertial core1232can be formed only in portions corresponding to the third coupling holes1231b4of the connection part1231. In order to increase centrifugal force, the inertial core1232can be formed as wide as possible, which is advantageous in terms of rotational inertia. For example, an outer diameter of the inertial core1232can be greater than an air gap between the stator121and the rotor122. Referring back toFIG.5, an outer diameter D2of the inertial core1232can be greater than an inner diameter D3of the stator coil1212(more precisely, a bundle of coils wound on an upper end of the stator core1211into an annular shape) such that a portion of the inertial core1232overlaps the stator coil1212in the radial direction. Accordingly, the outer diameter D2of the inertial core1232can be much greater than an outer diameter D4of the rotor core1221. However, an outer diameter D1of the connection part1231can be less than the outer diameter D2of the inertial core1232, and substantially the same as the outer diameter D4of the rotor core1221. As described above, by forming the thickness t of the inertial core1232as thin as possible to make the inertial core1232farther away from the permanent magnet1222as possible, magnetic flux leakage of the permanent magnet1222can be suppressed. At the same time, centrifugal force of the inertial core1232can be enhanced by increasing the outer diameter D2of the inertial core1232. Accordingly, rotational inertia of the inertial core1232can be increased to thereby suppress a decrease in efficiency of the motor and the compressor while reducing the size of the electric motor. In some implementations, a volume of the inertial core1232can be determined by rotational inertia of the rotor122excluding the connection part1231and the inertial core1232. In other words, rotational inertia of a rotating body including the rotor122, the connection part1231, and the inertial core123is related to efficiency of the compressor. If the rotational inertia of the rotating body is too low or too high, the efficiency of the compressor can be reduced. Therefore, a range of the rotational inertia of the rotating body should be appropriately secured (or determined) for the efficiency of the compressor. Since the rotational inertia of the rotor122is predetermined by the size (capacity) of the electric motor120, the rotational inertia of the inertial core1232(or the connection part included) can be a value obtained by subtracting rotational inertia of the rotor122from appropriate rotational inertia of the rotating body. FIG.10is a graph showing the compressor efficiency with respect to rotational inertia of a rotor including an inertial core. Referring toFIG.10, an x-axis represents a ratio calculated by dividing rotational inertia of the inertial core1232(or including the connection part) by rotational inertia of the rotor122, and a y-axis indicates the efficiency of the compressor. The graph shows that the rotational inertia of the inertial core1232should be greater than the rotational inertia of the rotor122, and the ratio calculated by dividing the rotational inertia of the inertial core1232by the rotational inertia of the rotor122should be in the range of 110 to 300%. Hereinafter, a description will be given of an example of an inertial core. That is, in the example described above, the connection part is bent in the zigzag shape such that portions supporting the inertial core are spaced apart from the rotor core. However, in some cases, the portions supporting the inertial core can be supported on the rotor core in the axial direction while being bent into the zigzag shape. FIG.11is an exploded perspective view illustrating an example of an inertial core, andFIG.12is an assembled front view ofFIG.11. Referring toFIGS.11and12, a connection part1231can be coupled to an inertial core1232as described above. The connection part1231can be formed in a wavy or zigzag shape, and the inertial core1232can be implemented as a flat plate with an annular shape. In detail, the connection part1231can include a plurality of first fixing portions1231a, second fixing portions1231b, and link portions1231cas described above. The first fixing portions1231aand the second fixing portions1231bcan be connected to each other by the link portions1231cso as to have an annular shape. The first fixing portions1231acan be supported on the rotor core1221, the second fixing portions1231bcan be supported on the inertial core1232, and the link portions1231ccan be obliquely bent to connect the first fixing portions1231aand the second fixing portions1231b. The basic configurations of the first fixing portion1231a, the second fixing portion1231b, and the link portion1231care similar to those of the example described above, so a detailed description thereof will be omitted. In this example, however, boss portions1231eextending from the first fixing portions1231aand/or the second fixing portions1231bin the axial direction can be further provided. The boss portion1231ecan extend from the connection part1231or the inertial core1232. However, when the boss portion1231eextends from the inertial core1232that is magnetic, magnetic flux leakage can be caused as the boss portion1231eof a magnetic material is disposed adjacent to the permanent magnet1222. Therefore, the boss portion1231ecan extend from the connection part1231, which is non-magnetic, and help to prevent the magnetic flux leakage. In some implementations, the boss portions1231ecan extend from the first fixing portions1231atoward the inertial core1232, or extend from the second fixing portions1231btoward the rotor core1221. However, in this implementation, an example in which the boss portions1231eextend from both of the first fixing portions1231aand the second fixing portions1231bwill be described. Referring toFIGS.11and12, the boss portions1231ecan axially extend from the first fixing portion1231aand the second fixing portion1231bof the connection part1231, respectively. A fifth coupling hole1231e1can be formed through each of the boss portions1231ein the axial direction. The fifth coupling hole1231e1can be formed on the same axis as the first coupling hole1221cof the rotor core1221, the second coupling hole1231a4of the first fixing portion1231a(or the third coupling hole of the second fixing portion), and the fourth coupling hole1232dof the inertial core1232in a communicating manner. A length of the boss portion1231ecan be approximately equal to a value obtained by subtracting a thickness of the first fixing portion1231a(or the second fixing portion) from a height of the link portion1231c, namely, a height of the connection part1231. Accordingly, an upper end of the boss portion1231ethat extends from an upper surface of the first fixing portion1231acan have substantially the same height as an upper surface of the second fixing portion1231b, and a lower end of the boss portion1231ethat extends from a lower surface of the second fixing portion1231bcan have substantially the same height as a lower surface of the first fixing portion1231a. Since the inertial core1232in this example is almost the same as the inertial core of the example described above, a detailed description thereof will be omitted. However, in this implementation, as the fifth coupling hole1231e1is defined in each of the boss portions1231eof the connection part1231, a bearing portion through hole1232bwith a circular shape can be formed at the center of the inertial core1232. As such, when the boss portion1231eextends from the connection part1231in the axial direction, the boss portion1231ecan axially support the connection part1231with respect to the rotor core1221. Accordingly, buckling of the connection part1231can be suppressed to thereby increase the reliability of the connection part1231and the inertial core1232. In particular, buckling of the connection part1231, which can be caused when the connection part1231is made of a non-metal such as plastic, can be effectively prevented. In some examples, when the inertial core1232is coupled to the rotor core1221by third coupling members1243penetrating from an upper end of the inertial core1232to the lower end of the rotor core1221, buckling of the connection part1231can be caused by a coupling force applied when coupling the coupling member1243. This can be caused more when the connection part1231is a non-metal. However, as in this implementation, when the boss portion1231eis provided at the connection part1231, the buckling of the connection part1231can be effectively suppressed even when the third coupling members1243are coupled through the rotor core1221and the inertial core1232entirely in the axial direction. In this case, an inner circumferential surface of the inertial core1232can be formed in a circular shape to thereby achieve a simpler structure of the inertial core1232. This can result in facilitating the manufacture of the inertial core1232, and increasing weight of the inertial core1232in relation to its outer diameter, which is advantageous to increase rotational inertia. As the third coupling member1243passes through both the inertial core1232and the connection part1231to be coupled to the rotor core1221, the rotor core1221and the inertial core1232can be coupled by the same third coupling member1243. Accordingly, coupling of the rotor core1221and the inertial core1232can be simplified to thereby reduce manufacturing costs. In some examples, as the boss portion1231eextends from the connection part1231in the axial direction and is spaced apart from the adjacent link portion1231c, a fluid flow path F can be formed between the link portions1231cof the connection part1231as in the example described above. Accordingly, fluid resistance caused by the connection part1231and the inertial core1232when the rotor122rotates can be reduced while allowing the inertial core1232to be installed on the rotor122. Although not shown in the drawings, the boss portions can be separated from the connection part and manufactured separately. Its basic structure and operational effects are similar to those of the example described above, a detailed description thereof will be omitted. Hereinafter, a description will be given of an example of an inertial core. That is, in the examples described above, the connection part has the annular shape and is bent in the zigzag shape. However, in some cases, the connection part can have a boss shape extending in the axial direction. FIG.13is an exploded perspective view illustrating an example of an inertial core, andFIG.14is an assembled front view ofFIG.13. Referring toFIGS.13and14, a connection part1231according to this example can be coupled to an inertial core1232as in the examples described above. However, the connection part1231can include a plurality of support bosses1231f. The plurality of support bosses1231fcan be connected to each other by a connecting rib1231g. The plurality of support bosses1231fcan have cross-sectional areas the same as or similar to the first fixing portions1231a, as illustrated inFIG.8, and be disposed at the same positions as the first fixing portions1231a. Accordingly, one support boss1231fcan support two permanent magnets1222respectively inserted into two permanent magnet mounting holes1221bfacing each other in the circumferential direction of the rotor core1221. The plurality of support bosses1231fcan each have a fifth coupling hole1231f1formed therethrough in the axial direction. The fifth coupling hole1231f1can be formed on the same axis as the first coupling hole1221cof the rotor core1221and the fourth coupling hole1232dof the inertial core1232. Accordingly, the inertial core1232can be coupled to the rotor core1221by the third coupling member1243with a long length that passes through the first coupling hole1221cof the rotor core1221, the fifth coupling hole1231f1of the support boss1231f, and the fourth coupling hole1232dof the inertial core1232. Each of the plurality of support bosses1231fcan have an axial length that can allow the inertial core1232to secure an appropriate insulation distance h from the rotor core1221, as in the examples described above. Accordingly, magnetic flux leakage from the rotor core1221(more precisely, the permanent magnet) to the inertial core1232can be suppressed by the connection part1231made of the non-magnetic material. The connecting rib1231gcan extend from a lower or upper outer circumferential surface of one support boss1231ftoward a lower or upper outer circumferential surface of another support boss1231f, so as to connect the plurality of support bosses1231fto each other. As the plurality of support bosses1231fare connected together, the connection part1231can be easily assembled. Since the inertial core1232is almost the same as the inertial core of the examples described above, a detailed description thereof will be omitted. However, in this implementation, as a sixth coupling hole1231f1is defined in each of the support bosses1231fof the connection part1231, a bearing portion through hole1232bwith a circular shape can be formed at the center of the inertial core1232. As the connection part1231is made of the non-magnetic material and is implemented as the support boss1231fhaving a predetermined length in the axial direction, the inertial core1232can be coupled to the rotor core1221without buckling of the connection part1231caused by a coupling force applied when coupling the inertial core1232to the rotor core1221. As the connection part1231is configured as the plurality of support bosses1231f, the material cost of the connection part1231can be reduced. In some examples, a fluid flow path F can be formed between the support bosses1231fdefining the connection part1231. This can result in reducing fluid resistance during rotation of the rotor122to thereby increase the motor efficiency while allowing the connection part1231to be installed on the rotor122. In some implementations, the plurality of support bosses can be formed independently of each other without being connected together by the connecting rib. Its basic configuration and effects are similar to those of the examples described above, a detailed description thereof will be omitted. However, in this case, the amount of use of non-magnetic material can be further reduced and the area of fluid flow path can be further increased. Hereinafter, a description will be given of an example of an inertial core. That is, in the examples described above, the connection part is made of the non-magnetic material, and the inertial core is made of the magnetic material. However, in some cases, both the connection part and the inertial core can be made of magnetic materials. FIG.15is an exploded perspective view of an example of an inertial core,FIG.16is an assembled front view ofFIG.15,FIG.17is a cross-sectional view taken along the line “IV-IV” ofFIG.16, andFIG.18is a graph showing a reduction rate of back electromotive force according to an overlapping area ratio of an inertial core and a permanent magnet. Referring toFIGS.15and16, an inertial core1232can be integrally formed with a connection part1231implemented as a boss portion. More specifically, the connection part1231can integrally extend from a lower surface of the inertial core1232defining a body portion in the axial direction. Accordingly, the connection part1231can be formed of a magnetic material the same as the inertial core1232. The connection part1231can have a single cylindrical shape. In this case, however, a contact area between the connection part1231and the permanent magnet1222can increase, and magnetic flux leakage can be increased accordingly. Thus, the connection part1231can extend from the inertial core1232, and be provided in plurality along the circumferential direction. In some examples, the plurality of connection parts1231can have the same cross-sectional area as the first fixing portions1231a, as illustrated inFIG.8. In other examples, the plurality of connection parts1231can have smaller cross-sectional areas than the first fixing portions1231a, and be located at the same positions as the first fixing portions1231a. Accordingly, the plurality of connection parts1231can support axial end surfaces of the permanent magnets1222inserted into the respective magnet mounting holes1221bof the rotor core1221. For example, a center of one connection part1231can be disposed between two adjacent permanent magnets1222so as to cover both of the two permanent magnets1222while supporting them in the axial direction. A seventh coupling hole1231hcan be defined in each of the plurality of connection parts1231. In other words, the seventh coupling holes1231hcan be formed at the plurality of connection parts1231, respectively. The seventh coupling hole1231hcan extend on the same axis from a lower end of the connection part1231to an upper surface of the inertial core1232. Accordingly, the inertial core1232including the connection parts1231can be coupled to the rotor core1221by the long third coupling members1243that penetrate from the upper end of the inertial core1232to the lower end of the rotor core1221. Even in this case, the rotor core1221can be coupled by the third coupling members1243and the first coupling members1241each having an intermediate length and disposed between two third coupling members1243in the circumferential direction. The plurality of connection parts1231can have the same axial length. For example, the connection parts1231can each have an axial length that allows the inertial core1232to secure an appropriate insulation distance h from the rotor core1221as in the examples described above, which can be suitable for suppressing magnetic flux leakage. Since the connection parts1231is made of the magnetic material as described above, magnetic flux leakage from the permanent magnets1222inserted into the rotor core1221can occur through the connection parts1231. However, as illustrated inFIG.17, the connection parts1231can be configured such that ends of two permanent magnets1222facing each other are supported by one connection part1231provided in an overlapping manner. By minimizing an overlapping area between the magnetic connection part1231and the permanent magnets1222, magnetic flux leakage can be reduced. For example, referring toFIG.18, when a cross-sectional area of the permanent magnet1222is A1and a cross-sectional area of the connection part1231overlapping the permanent magnet1222is A2, A2/A1can be approximately 60% or less. When A2/A1is approximately 60% or more, it can be seen that a reduction rate of back electromotive force (BEMF) is 1% or more. Thus, A2/A1should be approximately 60% or less for controlling the reduction rate of the BEMF at 1% or less, allowing a decrease in efficiency of the motor and the compressor to be suppressed. Since the inertial core1232is substantially the same as the inertial core of the example ofFIG.3orFIG.13, a detailed description thereof will be omitted. However, as the inertial core1232is integrally formed with the connection part1231, the inertial core1232can be made of the same magnetic material as the connection part1231. As two permanent magnets1222are axially supported by one connection part1231implemented as the boss portion, the connection part1231can be formed of the magnetic material, and a contact area between the connection part1231and the permanent magnets1222can be reduced, thereby minimizing magnetic flux leakage. This can lower the reduction rate of the BEMF to thereby suppress a decrease in efficiency of the motor and the compressor. In some examples, the plurality of permanent magnets1222can be securely supported while minimizing the number of connection parts1231implemented as the boss portion. Accordingly, a wide (or large) fluid flow path F can be secured between the rotor core1221and the inertial core1232to thereby reduce fluid resistance, allowing the efficiency of the motor and the compressor to be increased. Hereinafter, a description will be given of an example of an inertial core. That is, in the examples described, the inertial core is formed in a flat plate shape having the same thickness at a central portion and an edge portion. However, in some cases, the central portion and the edge portion can have different thicknesses. FIG.19is a perspective view illustrating an example of an inertial core. Referring toFIG.19, an inertial core1232can have an annular shape and be further provided at its edge with a mass portion1232e. For example, the inertial core1232can include the mass portion1232eprotruding from an edge of an upper surface of a body portion1232ahaving an annular shape. In some implementations, the mass portion1232ecan be formed in an annular shape as shown inFIG.19. In some examples, an outer diameter of the mass portion1232ecan be equal to an outer diameter of the body portion1232a, but an inner diameter of the mass portion1232ecan be greater than an inner diameter of the body portion1232a. Then, the mass portion1232ecan be concentrated on the edge of the body portion1232aon the plan, and thus centrifugal force due to the mass portion1232ecan be enhanced. The mass portion1232ecan be formed as a single body with the body portion1232a. In some examples, the mass portion1232ecan be formed in various manners. For example, the mass portion1232ecan be assembled or attached to the upper surface of the body portion1232a, formed by folding or rolling, or formed by bending. In some implementations, the mass portion can be formed eccentrically. For example, the mass portion can have an arcuate shape. In this case, the mass portion serves as a balance weight. Therefore, when the mass portion is formed eccentrically, it can be appropriately formed in consideration of the degree of unbalance of the electric motor such as the plate portion that is provided on the rotating shaft and serves as a balance weight and the like. When the mass portion1232eis formed at the body portion1232aof the inertial core1232, weight of the inertial core1232can be increased under the condition that the outer diameter of the inertial core1232is the same. This can increase rotational inertia of the inertial core1232to thereby improve the motor efficiency of the electric motor and the compressor efficiency. Hereinafter, a description will be given of an example of an inertial core. That is, in the examples described above, the inertial core and the rotor core made of different materials are assembled together. However, in some cases, the inertial core can be made of the same material as the rotor core. FIG.20is an exploded perspective view illustrating an example of a rotor core and an inertial core, andFIG.21is an assembled front view ofFIG.20. Referring toFIGS.20and21, an inertial core125can be coupled to one end of a rotor core1221in the axial direction defining the rotor122. Since the rotor core1221can be the same as or similar to the examples described above, a detailed description thereof will be omitted. The inertial core125can include a first inertial core1251and a second inertial core1252. Either one of the first inertial core1251or the second inertial core1252can be made of the same material and the same method as the rotor core1221. In this implementation, the first inertial core1251that is coupled to the rotor core1221can be made of the same material and the same method as the rotor core1221. In some examples, a through hole1251aextending from the shaft hole of the rotor core1221can be formed at a center of the first inertial core1251, and coupling holes1251bcan be defined in a circumference of the through hole1251a. The coupling holes1251bof the first inertial core1251can be formed on the same axis as the coupling holes of the rotor core1221, and coupling holes1252dof the second inertial core1252to be described hereinafter. Accordingly, the first inertial core1251together with the second inertial core1252can be coupled to the upper end of the rotor core1221by the long third coupling members1243penetrating from an upper end of the second inertial core1252to the lower end of the rotor core1221. The first inertial core1251can be formed by stacking a plurality of electrical steel sheets like the rotor core1221. Accordingly, the first inertial core1251can be magnetic the same as the rotor core1221. However, the first inertial core1251can be disposed so as not to be in direct contact with the permanent magnets1222inserted into the rotor core1221. For example, the rotor core1221can have substantially the same axial length as the stator core1121and be located within the stator core1121range, and the first inertial core1251can be located out of the axial range of the stator core1121. In some examples, the first inertial core1251can be disposed such that at least a portion thereof overlaps an end portion of the permanent magnet1222in the radial direction, thereby restricting separation of the permanent magnet1222in the axial direction. In detail, the first inertial core1251can be located above the rotor core1221in the axial direction and located more radially inward than the permanent magnet1222. A magnet support protrusion1252cextending in the radial direction to overlap the permanent magnet1222in the radial direction can be further provided at an outer surface of the first inertial core1251, more specifically, the outermost electrical steel sheet of the first inertial core1251that is in contact with the rotor core1221. The magnet support protrusion1252ccan allow the first inertial core1251to be located more inward than the permanent magnet1222and restrict an axial separation of the permanent magnet1222. In some examples, the first inertial core1251can have a length capable of minimizing magnetic flux leakage from the permanent magnet1222, for example, a length greater (longer) than a thickness of the second inertial core1252to be described hereinafter, or at least 4 mm or more. As a result, magnetic flux leakage from the permanent magnet1222to the second inertial core1252to be described later can be suppressed. The second inertial core1252can be coupled by being in close contact with the upper surface of the rotor core1221. The second inertial core1252can be coupled to the first inertial core1251by the third coupling members1243penetrating through the rotor core1221, or by welding or an adhesive. Other configurations that allow the second inertial core1252to be firmly coupled to the rotor core1221, such as being coupled to the first inertial core1251in an engaged manner, can also be available. In some implementations, the second inertial core1252can be coupled to the rotor core1221. The basic configuration and operational effects of the second inertial core1252are similar to those of the inertial core of the examples described above, so a detailed description thereof will be omitted. That is, a mass portion1252aof the second inertial core1252can have a disk shape so that a shaft hole1252bis defined at a center thereof, and a plurality of coupling holes1252dare formed around the shaft hole1252b. Since the second inertial core1252is formed of a magnetic material and is coupled to the first inertial core1251that is also made of a magnetic material, magnetic flux leakage from the permanent magnet1222can be facilitated. However, the first inertial core1251can be configured to minimize an overlapping area with the permanent magnet1222and at the same time secure an axial height of the first inertial core1251as long (great) as possible, for example, 4 mm or more at which the reduction rate of back electromotive force is less than 1%. Accordingly, both the first inertial core1251and the second inertial core1252can be made of the magnetic material, and the magnetic flux leakage from the permanent magnet1222can be minimized. In some examples, an outer diameter of the second inertial core1252can be greater than an outer diameter of the rotor core1221enough to overlap the stator coil1212in the radial direction. Accordingly, centrifugal force of the second inertial core1252can be increased to thereby enhance rotational inertia of the rotor122. In some implementations, insulation pads made of a non-magnetic material can be disposed between the rotor core1221and the first inertial core1251, and between the first inertial core1251and the second inertial core1252, respectively. However, the first inertial core1251can be have an axial length (e.g., 4 mm or more) capable of minimizing magnetic flux leakage from the permanent magnet1222. In this case, the second inertial core1252can secure an appropriate insulation distance from the permanent magnet1222to thereby minimize a thickness of the insulation pad. For example, by forming the insulation pad much thinner than the second inertial core1252, an increase in manufacturing costs due to an excessive use of the non-magnetic material can be suppressed. Hereinafter, a description will be given of an example of an inertial core. That is, in the previous example, the inertial core is implemented as the first inertial core and the second inertial core, but in some cases, a third inertial core can be further provided. FIG.22is an assembled front view illustrating examples of a rotor core and an inertial core. Referring toFIG.22, a rotor core1221can be formed in the same manner as the rotor core ofFIG.20. Thus, a detailed description thereof will be omitted. An inertial core125can include a first inertial core1251and a second inertial core1252provided at one end (e.g., lower end) of the rotor core1221in the axial direction, and a third inertial core1253provided at another end of the rotor core1221in the axial direction. The basic configurations of the first inertial core1251and the second inertial core1252are similar to those of the example ofFIG.20. The first inertial core1251is formed by stacking electrical steel sheets like the rotor core1221, which is the same as the first inertial core inFIG.20, so a description thereof will be omitted. However, the second inertial core1252can be different from the second inertial core inFIG.20. For example, an outer diameter of the second inertial core1252can be the same as the outer diameter of the rotor core1221, and a mass portion1253acan be further provided. The mass portion1253acan be formed in an annular shape. In some examples, the mass portion1253acan alternatively be formed in an arcuate shape to be eccentric in a direction opposite to the mass portion1253aof the third inertial core1253. The third inertial core1253can be coupled to the upper end of the rotor core1221, and cover and support one end of the permanent magnet in the axial direction that is inserted into the rotor core1221. Accordingly, magnetic flux leakage can be minimized when the third inertial core1253is made of a non-magnetic material. The third inertial core1253can be formed substantially the same as the second inertial core1252. For example, an outer diameter of the third inertial core1253can be substantially the same as the outer diameter of the rotor core1221. Accordingly, a relatively expensive non-magnetic material used for the third inertial core1253can be reduced to thereby suppress an increase in manufacturing costs of the inertial core125of the electric motor. The third inertial core1253can be provided with the mass portion1253ahaving an arcuate shape. The mass portion1253aof the third inertial core1253can be configured such that eccentric mass is generated in a direction opposite to a mass portion1252aof the second inertial core1252. Accordingly, an unbalanced force transmitted through the rotating shaft130can be effectively offset by the second inertial core1252and the third inertial core1253. As the first inertial core1251and the second inertial core1252are mounted on one end of the rotor core1221, and the third inertial core1253is mounted on another end of the rotor core1221, rotational inertia of the rotor can be increased even when the electric motor is reduced in size, thereby improving the motor efficiency. The foregoing description has been given of specific implementations of the present disclosure. However, the present disclosure can be implemented in various forms without departing from the spirit or essential characteristics thereof, and thus the implementations described above should not be limited by the detailed description provided herein. Moreover, even if any implementation is not specifically disclosed in the foregoing detailed description, it should be broadly construed within the scope of the technical idea, as defined in the accompanying claims. Furthermore, all modifications and variations that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims. | 79,628 |
11863022 | DETAILED DESCRIPTION A Z-axis direction appropriately illustrated in each drawing is an up-and-down direction in which a positive side is an “upper side” and a negative side is a “lower side”. A central axis J appropriately illustrated in each drawing is a virtual line which is parallel to the Z-axis direction and extends in the up-and-down direction. In the following description, an axial direction of the central axis J, that is, a direction parallel to the up-and-down direction will be simply referred to as the “axial direction”, a radial direction having its center on the central axis J will be simply referred to as the “radial direction”, and a circumferential direction having its center on the central axis J will be simply referred to as the “circumferential direction”. In addition, a side proceeding counterclockwise in the circumferential direction when viewed from the upper side to the lower side is referred to as “one side in the circumferential direction”. A side proceeding clockwise in the circumferential direction when viewed from the upper side to the lower side is referred to as the “other side in the circumferential direction”. The one side in the circumferential direction is a side proceeding in a direction of an arrow indicating a rotation angle θ inFIGS.2and3. The other side in the circumferential direction is a side proceeding in a direction opposite to the direction of the arrow indicating the rotation angle θ inFIGS.2and3. In the embodiment, the lower side corresponds to one side in an axial direction, and the upper side corresponds to the other side in the axial direction. In the present embodiment, the radially outer side corresponds to one side in the radial direction, and the radially inner side corresponds to the other side in the radial direction. Note that the up-and-down direction, the upper side, and the lower side are simply names for describing an arrangement relationship of each portion, and an actual arrangement relationship or the like may be an arrangement relationship other than the arrangement relationship indicated by these names. As illustrated inFIG.1, a motor10of the present embodiment is mounted on a rotor blade device1. The rotor blade device1is mounted on, for example, an unmanned flying object. The rotor blade device1includes the motor10and a propeller2. In the present embodiment, the motor10is an inner-rotor motor. The motor10includes a housing40, a stator30, a busbar assembly60, a rotor20, a first bearing71, a second bearing72, a propeller mounting portion80, and a sensor assembly50. The rotor20, the stator30, the sensor assembly50, the busbar assembly60, the first bearing71, and the second bearing72are accommodated in the housing40. A plurality of fins45arranged along the circumferential direction are provided on an outer peripheral surface of the housing40. In the present embodiment, the stator30is located on the radially outer side of the rotor20. The stator30includes a stator core31, an insulator32, and a plurality of coils33. As illustrated inFIGS.2and3, the stator core31includes a core back31aand a plurality of teeth31b. The core back31ahas an annular shape surrounding the central axis J. The core back31ahas, for example, an annular shape centered on the central axis J. The plurality of teeth31bextend to the radially inner side from the core back31a. The plurality of teeth31bare arranged at regular intervals along the circumferential direction over the entire circumference. For example, eighteen teeth31bare provided. The plurality of coils33are attached to the stator core31with the insulator32interposed therebetween. More specifically, the plurality of coils33are attached to the plurality of teeth31bvia the insulator32. Note that the insulator32is not illustrated inFIGS.2and3. As illustrated inFIG.1, the busbar assembly60is located below the stator30. The busbar assembly60is located on the radially outer side of the sensor assembly50. The busbar assembly60includes a busbar holder61and a busbar62. The busbar holder61holds the busbar62. The busbar62is electrically connected to the coil33. The rotor20is rotatable about the central axis J. In the present embodiment, the rotor20is located on the radially inner side of the stator30. The rotor20includes a shaft21, a rotor core22, and a rotor magnet23. The shaft21is arranged along the central axis J. The shaft21has a columnar shape that extends in the axial direction with the central axis J as the center. An upper end of the shaft21protrudes upward from the housing40. The rotor core22is fixed to an outer peripheral surface of the shaft21. The rotor core22has an annular shape surrounding the central axis J. In the present embodiment, the rotor core22has the annular shape centered on the central axis J. The rotor magnet23is fixed to the rotor core22. The rotor magnet23has a tubular shape surrounding the rotor core22. The rotor magnet23has, for example, a cylindrical shape that extends in the axial direction with the central axis J as the center and is open on both sides in the axial direction. An inner peripheral surface of the rotor magnet23is fixed to an outer peripheral surface of the rotor core22with, for example, an adhesive or the like. In the present embodiment, a lower end of the rotor magnet23is located below a lower end of the rotor core22and a lower end of the stator core31. In the present embodiment, an upper end of the rotor magnet23is located at the same position in the axial direction as an upper end of the rotor core22. As illustrated inFIGS.2and3, the rotor magnet23includes a plurality of magnetized portions23a. In the present embodiment, the plurality of magnetized portions23aare magnets that are separate members from each other. The rotor magnet23is configured by connecting the plurality of magnetized portions23aalong the circumferential direction. As illustrated inFIG.3, the plurality of magnetized portions23ahave, for example, a quadrangular prism shape extending in the axial direction. Each of the magnetized portions23ais configured by, for example, connecting two magnets in the axial direction. A circumferential dimension of the magnetized portion23ais smaller than a circumferential dimension of the tooth31b. In the present embodiment, four or five magnetized portions23acan simultaneously face one tooth31bin the radial direction. For example, eighty magnetized portions23aare provided. The plurality of magnetized portions23aare arranged along the circumferential direction in a Halbach array for increasing the magnetic field intensity on the radially outer side. The plurality of magnetized portions23ainclude a plurality of radially magnetized portions23band a plurality of non-radially magnetized portions23c. The radially magnetized portion23bis the magnetized portion23awhose magnetization direction is the radial direction. The non-radially magnetized portion23cis the magnetized portion23awhose magnetization direction is different from the radial direction. Note that the magnetization directions of the magnetized portions23aare virtually indicated by arrows on upper end surfaces of the magnetized portions23ainFIG.3. The direction of the virtually indicated arrow indicates a direction from an S pole to an N pole in the magnetized portion23a. That is, magnetic poles of the magnetized portion23aare set such that a side on which the virtually indicated arrow faces is the N pole and a side opposite to the side on which the virtually indicated arrow faces is the S pole. In the following description, the direction of the virtually indicated arrow, that is, the direction from the S pole to the N pole in the magnetized portion23ais simply referred to as a “direction of a magnetization direction”. The radially magnetized portion23bincludes a first radially magnetized portion24aand a second radially magnetized portion24b. A direction of a magnetization direction of the first radially magnetized portion24ais a radially inward direction. That is, magnetic poles of the first radially magnetized portion24aare set such that the radially inner side is an N pole and the radially outer side is an S pole. A direction of a magnetization direction of the second radially magnetized portion24bis a radially outward direction. That is, magnetic poles of the second radially magnetized portion24bare set such that the radially outer side is an N pole and the radially inner side is an S pole. In the second radially magnetized portion24b, the magnetic poles on both the sides in the radial direction are arranged opposite to those of the first radially magnetized portion24a. The first radially magnetized portions24aand the second radially magnetized portions24bare alternately arranged along the circumferential direction with at least one of non-radially magnetized portions23cinterposed therebetween. In the present embodiment, the first radially magnetized portions24aand the second radially magnetized portions24bare alternately arranged along the circumferential direction with three non-radially magnetized portion23cinterposed therebetween. The non-radially magnetized portion23cincludes first non-radially magnetized portions25aand25band second non-radially magnetized portions26a,26b,26c, and26d. Magnetization directions of the first non-radially magnetized portions25aand25bare the circumferential direction. A direction of the magnetization direction of the first non-radially magnetized portion25ais a direction toward one side (+θ side) in the circumferential direction. That is, magnetic poles of the first non-radially magnetized portion25aare set such that the one side in the circumferential direction is an N pole and the other side (−θ side) in the circumferential direction is an S pole. A direction of the magnetization direction of the first non-radially magnetized portion25bis a direction toward the other side in the circumferential direction. That is, magnetic poles of the first non-radially magnetized portion25bare set such that the other side in the circumferential direction is an N pole and the one side in the circumferential direction is an S pole. In the first non-radially magnetized portion25b, the magnetic poles on both the sides in the circumferential direction are arranged opposite to those of the first non-radially magnetized portion25a. Each of the first non-radially magnetized portions25aand25bis located between the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction. The first non-radially magnetized portions25aand the first non-radially magnetized portions25bare alternately arranged along the circumferential direction with any one of the first radially magnetized portion24aand the second radially magnetized portion24binterposed therebetween. The first non-radially magnetized portion25ais located on one side (+θ side) in the circumferential direction of the first radially magnetized portion24aand is located on the other side (−θ side) in the circumferential direction of the second radially magnetized portion24bbetween the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction. The first non-radially magnetized portion25bis located on the other side in the circumferential direction of the first radially magnetized portion24aand is located on the one side in the circumferential direction of the second radially magnetized portion24bbetween the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction. The N poles of the first non-radially magnetized portions25aand25bare arranged on a side where the second radially magnetized portion24bis located, between the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction. The S poles of the first non-radially magnetized portions25aand25bare arranged on a side where the first radially magnetized portion24ais located, between the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction. Magnetization directions of the second non-radially magnetized portions26a,26b,26c, and26dare directions intersecting both the radial direction and the circumferential direction. The magnetization directions of the second non-radially magnetized portions26a,26b,26c, and26dare orthogonal to the axial direction. In the present embodiment, the magnetization directions of the second non-radially magnetized portions26a,26b,26c, and26dare directions inclined by 45° in the circumferential direction with respect to the radial direction. The magnetization directions of the second non-radially magnetized portions26aand26care directions located on one side (+θ side) in the circumferential direction as proceeding to the radially inner side. The magnetization directions of the second non-radially magnetized portions26band26dare directions located on the other side (−θ side) in the circumferential direction as proceeding to the radially inner side. In the present embodiment, directions of the magnetization directions of the second non-radially magnetized portions26a,26b,26c, and26dare directions each of which is inclined by 45° toward the direction of the magnetization direction of the magnetized portion23aadjacent on the other side (−θ side) in the circumferential direction with respect to the direction of the magnetization direction of the magnetized portion23aadjacent on one side (+θ side) in the circumferential direction. The direction of the magnetization direction of the second non-radially magnetized portion26ais a direction toward one side (+θ side) in the circumferential direction that is inclined radially inward. That is, the second non-radially magnetized portion26ahas an N pole on the radially inner side and the one side in the circumferential direction and an S pole on the radially outer side and the other side (−θ side) in the circumferential direction. The direction of the magnetization direction of the second non-radially magnetized portion26bis a direction toward one side in the circumferential direction that is inclined radially outward. That is, the second non-radially magnetized portion26bhas an N pole on the radially outer side and the one side in the circumferential direction and an S pole on the radially inner side and the other side in the circumferential direction. The direction of the magnetization direction of the second non-radially magnetized portion26cis a direction toward the other side in the circumferential direction that is inclined radially outward. That is, the second non-radially magnetized portion26chas an N pole on the radially outer side and the other side in the circumferential direction and an S pole on the radially inner side and the one side in the circumferential direction. The direction of the magnetization direction of the second non-radially magnetized portion26dis a direction toward the other side in the circumferential direction that is inclined radially inward. That is, the second non-radially magnetized portion26dhas an N pole on the radially inner side and the other side in the circumferential direction and an S pole on the radially outer side and the one side in the circumferential direction. The second non-radially magnetized portions26aand26bare arranged adjacent to each other on both the sides in the circumferential direction of the first non-radially magnetized portion25a. The second non-radially magnetized portions26cand26dare arranged adjacent to each other on both the sides in the circumferential direction of the first non-radially magnetized portion25b. The second non-radially magnetized portions26aand26dare arranged adjacent to each other on both the sides in the circumferential direction of the first radially magnetized portion24a. The second non-radially magnetized portions26band26care arranged adjacent to each other on both the sides in the circumferential direction of the second radially magnetized portion24b. The second non-radially magnetized portion26ais located between the first radially magnetized portion24aand the first non-radially magnetized portion25ain the circumferential direction. The second non-radially magnetized portion26bis located between the second radially magnetized portion24band the first non-radially magnetized portion25ain the circumferential direction. The second non-radially magnetized portion26cis located between the second radially magnetized portion24band the first non-radially magnetized portion25bin the circumferential direction. The second non-radially magnetized portion26dis located between the first radially magnetized portion24aand the first non-radially magnetized portion25bin the circumferential direction. In this manner, each of the second non-radially magnetized portions26a,26b,26c, and26dis located between the radially magnetized portion23band each of the first non-radially magnetized portions25aand25bin the circumferential direction. In the rotor magnet23, a plurality of array patterns in which the plurality of magnetized portions23aare arrayed along the circumferential direction are continuously formed over the entire circumference. The array patterns of the magnetized portions23aforming the rotor magnet23are array patterns in which the first radially magnetized portions24a, the second non-radially magnetized portion26a, the first non-radially magnetized portion25a, the second non-radially magnetized portion26b, the second radially magnetized portion24b, the second non-radially magnetized portion26c, the first non-radially magnetized portion25b, and the second non-radially magnetized portions26dare arrayed in this order toward the one side in the circumferential direction. As a result, the rotor magnet23has the Halbach array in which the magnetic field intensity on the radially outer side is increased. Therefore, the magnetic force generated between the rotor20and the stator30can be increased, and the output of the motor10can be improved. In the present embodiment, an axial dimension of the radially magnetized portion23band an axial dimension of each of the second non-radially magnetized portions26a,26b,26c, and26dare the same. An axial dimension of each of the first non-radially magnetized portions25aand25bis smaller than the axial dimension of the radially magnetized portion23band the axial dimension of each of the second non-radially magnetized portions26a,26b,26c, and26d. Upper ends of the second non-radially magnetized portions26a,26b,26c, and26dare located at the same position in the axial direction as an upper end of the radially magnetized portion23b. Lower ends of the second non-radially magnetized portions26a,26b,26c, and26dare located at the same position in the axial direction as a lower end of the radially magnetized portion23b. Upper ends of the first non-radially magnetized portions25aand25bare located at the same position in the axial direction as the upper end of the radially magnetized portion23band the upper ends of the second non-radially magnetized portions26a,26b,26c, and26d. Lower ends of the first non-radially magnetized portions25aand25bare located above the lower end of the radially magnetized portion23band the lower ends of the second non-radially magnetized portions26a,26b,26c, and26d. Therefore, void portions27are provided below the first non-radially magnetized portions25aand25b, respectively. In the present embodiment, the void portion27is provided at a lower end of the rotor magnet23. As illustrated inFIG.4, an upper end of the void portion27, that is, the lower ends of the first non-radially magnetized portions25aand25bare located at the same position in the axial direction as a lower end of the rotor core22, for example. Since the void portion27is provided, the lower end of the rotor magnet23is constituted by the lower end of the first radially magnetized portion24a, the lower end of the second radially magnetized portion24b, and the lower ends of the second non-radially magnetized portions26a,26b,26c, and26din the present embodiment. As illustrated inFIG.3, the plurality of void portions27are arranged at equal intervals over the entire circumference along the circumferential direction. Each of the void portions27is located between the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction. The void portion27is a gap between the lower ends of the second non-radially magnetized portions26aand26badjacent to both the sides in the circumferential direction of the first non-radially magnetized portion25a, or a gap between the lower ends of the second non-radially magnetized portions26cand26dadjacent to both the sides in the circumferential of the first non-radially magnetized portion25b. That is, the lower end of the second non-radially magnetized portion26aand the lower end of the second non-radially magnetized portion26bface each other in the circumferential direction with the void portion27interposed therebetween. The lower end of the second non-radially magnetized portion26cand the lower end of the second non-radially magnetized portion26dface each other in the circumferential direction with the void portion27interposed therebetween. In the present embodiment, the void portion27corresponds to a non-magnetized portion. Note that it suffices that the “non-magnetized portion” in the present specification is a portion having no magnetic pole. That is, the non-magnetized portion may be a void portion as in the present embodiment, may be another member that is not magnetized, or may be a portion of the rotor magnet that is not magnetized. When the non-magnetized portion is a member that is not magnetized, the member that is not magnetized may be arranged in a void portion provided as in the present embodiment. As illustrated inFIG.1, the first bearing71and the second bearing72support the rotor20rotatably. The first bearing71and the second bearing72are, for example, ball bearings. The propeller mounting portion80is a portion on which the propeller2is mounted. The propeller mounting portion80is fixed to an upper end of the shaft21. The propeller mounting portion80is located outside the housing40. The sensor assembly50is located below the rotor core22. The sensor assembly50includes a sensor holder51, a circuit board53, and a magnetic sensor52. That is, the motor10includes the sensor holder51, the circuit board53, and the magnetic sensor52. The circuit board53is fixed to the sensor holder51. The circuit board53has a plate shape whose plate surface is directed in the axial direction. The magnetic sensor52is located above the circuit board53. As illustrated inFIG.4, the magnetic sensor52has a terminal52aextending downward. The terminal52ais connected to an upper surface of the circuit board53. As a result, the magnetic sensor52is electrically connected to the circuit board53. The magnetic sensor52is held by the sensor holder51. The magnetic sensor52is located below the rotor core22. The magnetic sensor52is located on the radially inner side of the rotor magnet23. In the present embodiment, the magnetic sensor52is located on the radially inner side of the lower end of the rotor magnet23. Here, the lower end of the rotor magnet23is located below the lower end of the rotor core22in the present embodiment. Therefore, the magnetic sensor52can be easily arranged on the radially inner side of the lower end of the rotor magnet23. In the present embodiment, an upper portion of the magnetic sensor52is located on the radially inner side of the lower end of the rotor magnet23. The magnetic sensor52faces the lower end of the rotor magnet23or the void portion27in the radial direction with a gap interposed therebetween. The magnetic sensor52can detect a magnetic field of the rotor magnet23. In the present embodiment, the magnetic sensor52can detect the magnetic field of the lower end of the rotor magnet23that faces the magnetic sensor52in the radial direction. That is, an axial portion of the rotor magnet23where the magnetic field in the present embodiment is detected by the magnetic sensor52is the lower end of the rotor magnet23. In addition, the void portion27in the present embodiment is provided in the axial portion of the rotor magnet23where the magnetic field is detected by the magnetic sensor52. Note that the “portion of the rotor magnet where the magnetic field is detected by the magnetic sensor” in the present specification includes a portion of the rotor magnet whose axial position is the same as an axial position of the magnetic sensor in a case where at least a part of the magnetic sensors is arranged at the same axial position as a part of the rotor magnet. That is, the lower end of the rotor magnet23in the present embodiment has the same axial position as the upper portion of the magnetic sensor52, and is included in the portion where the magnetic field is detected by the magnetic sensor52. In addition, the “portion of the rotor magnet where the magnetic field is detected by the magnetic sensor” in the present specification includes an axial end of the rotor magnet on a side close to the magnetic sensor in a case where the magnetic sensor is located above or below the rotor magnet. That is, in a case where the magnetic sensor52is located, for example, below the rotor magnet23, a lower end, close to the magnetic sensor52between axial ends of the rotor magnet23, is included in the portion where the magnetic field is detected by the magnetic sensor52. The magnetic sensor52in the present embodiment is, for example, a Hall element such as a Hall IC. Although not illustrated, a plurality of the magnetic sensors52are provided along the circumferential direction. The rotation of the rotor20can be detected by detecting the magnetic field of the rotor magnet23with the magnetic sensor52. The rotation of the rotor20may be detected by the magnetic sensor52itself, or may be detected by another portion based on a detection result of the magnetic sensor52. The other portion is, for example, a control unit (not illustrated) provided on the circuit board53. In this manner, the rotation of the rotor20can be detected using the magnetic field of the rotor magnet23without separately providing a magnet, configured for detection with the magnetic sensor52, in addition to the rotor magnet23according to the present embodiment. Therefore, the number of components of the motor10can be reduced. In addition, it is unnecessary to consider the mounting accuracy of the separately provided magnet, and the assembly of the motor10can be facilitated. In the case where the rotor magnet has the Halbach array in which the magnetic field intensity on the radially outer side is increased as in the rotor magnet23of the present embodiment, the magnetic flux hardly flows on the radially inner side of the rotor magnet, and the magnetic field intensity on the radially inner side of the rotor magnet decreases. Therefore, it is difficult for the magnetic sensor to detect the magnetic field of the rotor magnet on the radially inner side of the rotor magnet. In addition, in the case where the rotor magnet has the Halbach array in which the magnetic field intensity on the radially outer side is increased, a waveform of a magnetic flux density B detected by the magnetic sensor on the radially inner side of the rotor magnet changes in a cycle in which the magnetic pole of the rotor magnet is switched between the N pole and the S pole and vibrates in a cycle shorter than the switching period of the magnetic pole as indicated by a waveform CW indicated by a broken line inFIG.5. Therefore, the polarity of the magnetic flux density B is easily reversed before and after points P1and P2at which the magnetic pole of the rotor magnet is switched. As a result, it is difficult to accurately detect the points P1and P2at which the magnetic pole of the rotor magnet is switched, from the waveform CW of the magnetic flux density B detected by the magnetic sensor, and a circumferential position of the rotor is not accurately detectable in some cases. In the case where the rotor magnet has the Halbach array in which the magnetic field intensity on the radially outer side is increased as described above, there is a problem that the detection accuracy of the magnetic sensor deteriorates on the radially inner side of the rotor magnet. Note that, inFIG.5, the horizontal axis represents the rotation angle θ of the rotor, and the vertical axis represents the magnetic flux density B detected by the magnetic sensor on the radially inner side of the rotor magnet. In addition, inFIG.5, for example, it is assumed that the magnetic pole on the radially inner side of the rotor magnet facing the magnetic sensor is the N pole when the magnetic flux density B is a positive value, and the magnetic pole on the radially inner side of the rotor magnet facing the magnetic sensor is the S pole when the magnetic flux density B is a negative value. In addition, a waveform PW indicated by a solid line inFIG.5is an example of the waveform of the magnetic flux density B when the magnetic field of the rotor magnet23of the present embodiment is detected by the magnetic sensor52. The waveform CW indicated by the broken line inFIG.5is an example of the waveform of the magnetic flux density B when a magnetic field of a rotor magnet of a comparative embodiment is detected by the magnetic sensor52. The rotor magnet of the comparative embodiment is similar to the rotor magnet23of the present embodiment except that the void portion27is not provided. In view of the above problem, the void portion27as the non-magnetized portion, located between the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction, is provided in the axial portion of the rotor magnet23where the magnetic field is detected by the magnetic sensor52according to the present embodiment. Since the void portion27is the non-magnetized portion having no magnetic pole, the magnetic flux of the rotor magnet23easily flows radially inward in the void portion27. As a result, the amount of magnetic flux passing through the magnetic sensor52located on the radially inner side of the rotor magnet23can be increased, and a value of the magnetic flux density B detected by the magnetic sensor52can be increased. Therefore, the magnetic field of the rotor magnet23can be easily detected by the magnetic sensor52. In addition, in a change in the magnetic flux density B, a vibration in a cycle shorter than a cycle in which the magnetic pole is switched can be suppressed as compared with the waveform CW of the comparative embodiment as indicated by the waveform PW indicated by the solid line inFIG.5. In particular, the non-magnetized portion is located between the first radially magnetized portion24aand the second radially magnetized portion24bin the circumferential direction in which the magnetization direction is the radial direction and the magnetic poles are arranged opposite to each other. Therefore, it is possible to particularly cause the magnetic flux to easily flow radially inward between a portion where the magnetic pole on the radially inner side of the rotor magnet23becomes the N pole and a portion where the magnetic pole becomes the S pole in the circumferential direction, and it is particularly easy to suppress the vibration having the cycle shorter than the cycle in which the magnetic pole is switched. As a result, it is possible to suppress the occurrence of the polarity inversion of the magnetic flux density B before and after the points P1and P2at which the magnetic pole of the rotor magnet23is switched. Therefore, it is easy to accurately detect the points P1and P2at which the magnetic pole of the rotor magnet23is switched, from the waveform PW of the magnetic flux density B detected by the magnetic sensor52, and the detection accuracy of the circumferential position of the rotor20can be improved. As described above, even when the rotor magnet23has the Halbach array to increase the magnetic field intensity on the radially outer side, it is possible to suppress the decrease in detection accuracy of the magnetic sensor52on the radially inner side of the rotor magnet23by providing the non-magnetized portion in the axial portion of the rotor magnet23in which the magnetic field is detected by the magnetic sensor52. Therefore, it is possible to improve the detection accuracy of a rotational position of the rotor20while improving the output of the motor10by forming the rotor magnet23in the Halbach array according to the present embodiment. Note that the points P1and P2at which the magnetic pole of the rotor magnet23is switched in the present embodiment are, for example, the rotation angle θ of the rotor20when the void portion27faces the magnetic sensor52in the radial direction. In addition, according to the present embodiment, the axial portion of the rotor magnet23where the magnetic field is detected by the magnetic sensor52is the lower end of the rotor magnet23, and the void portion27, which is the non-magnetized portion, is provided at the lower end of the rotor magnet23. Therefore, it is easy to arrange the magnetic sensor52so as to face the rotor magnet23as compared with a case where the axial portion of the rotor magnet23where the magnetic field is detected by the magnetic sensor52is a central portion in the axial direction. As a result, the magnetic field of the rotor magnet23can be suitably detected by the magnetic sensor52while suppressing complexity of a structure of the motor10. In addition, it is possible to suppress a decrease in the amount of magnetic flux flowing between the rotor20and the stator30as compared with a case where the non-magnetized portion is provided at the central portion in the axial direction of the rotor magnet23or the like. Therefore, it is possible to suppress a decrease in the output of the motor10. In addition, the non-magnetized portions are the void portions27provided below the first non-radially magnetized portions25aand25baccording to the present embodiment. Therefore, for example, the non-magnetized portion can be easily provided by partially shortening the axial dimension of the magnetized portion23aforming the rotor magnet23as in the present embodiment. Therefore, the motor10can be easily manufactured. In addition, the axial dimensions of the first non-radially magnetized portions25aand25bare smaller than the axial dimension of the radially magnetized portion23baccording to the present embodiment. Therefore, it is possible to suppress the upper ends of the first non-radially magnetized portions25aand25bfrom protruding above the radially magnetized portion23bwhile providing the void portions27below the first non-radially magnetized portions25aand25b. As a result, it is possible to suppress an increase in size of the rotor20in the axial direction, and to suppress an increase in size of the motor10in the axial direction. In addition, the magnetization directions of the first non-radially magnetized portions25aand25bare the circumferential direction according to the present embodiment. Therefore, the first non-radially magnetized portions25aand25bguide the magnetic flux, which flows between the first radially magnetized portion24aand the second radially magnetized portion24b, in the circumferential direction inside the rotor magnet23, and can suitably suppress the magnetic flux from leaking radially inward. As a result, the amount of magnetic flux on the radially outer side of the rotor magnet23arranged in the Halbach array can be suitably increased by providing the first non-radially magnetized portions25aand25b. Accordingly, the output of the motor10can be further improved. Meanwhile, the amount of magnetic flux flowing to the radially inner side of the rotor magnet23having the Halbach array is further reduced by providing the first non-radially magnetized portions25aand25b. Therefore, it is particularly difficult for the magnetic sensor52to detect the magnetic field of the rotor magnet23on the radially inner side of the axial portion of the rotor magnet23where the first non-radially magnetized portions25aand25bare provided, so that the detection accuracy of the magnetic sensor52is more likely to decrease. On the other hand, according to the present embodiment, the lower ends of the first non-radially magnetized portions25aand25bwhose magnetization direction is the circumferential direction are located above the lower end of the radially magnetized portion23b, and the void portions27, which are the non-magnetized portions, are provided below the first non-radially magnetized portions25aand25b. Therefore, the first non-radially magnetized portions25aand25bare not provided at the lower end of the rotor magnet23, but the void portion27as the non-magnetized portion is provided instead. As a result, the magnetic flux can be suitably made to flow to the radially inner side of the rotor magnet23at the lower end of the rotor magnet23. Therefore, it is possible to further suppress the decrease in detection accuracy of the magnetic sensor52on the radially inner side of the rotor magnet23by detecting the magnetic field of the lower end of the rotor magnet23by the magnetic sensor52. In addition, the lower ends of the second non-radially magnetized portions26a,26b,26c, and26dwhose magnetization directions intersect both the radial direction and the circumferential direction are located at the same position in the axial direction as the lower end of the radially magnetized portion23baccording to the present embodiment. Therefore, the axial dimensions of the second non-radially magnetized portions26a,26b,26c, and26dcan be easily increased, and the volume of the entire rotor magnet23can be easily increased. Therefore, the magnetic field intensity on the radially outer side of the rotor magnet23can be more easily increased, and the output of the motor10can be further improved. In addition, the second non-radially magnetized portions26a,26b,26c, and26dhave less influence on the magnetic field increased by the Halbach array than the first non-radially magnetized portions25aand25bwhose magnetization direction is the circumferential direction. Therefore, if the first non-radially magnetized portions25aand25bare not provided by the void portion27, it is possible to cause the magnetic flux to sufficiently flow to the radially inner side of the rotor magnet23even when the second non-radially magnetized portions26a,26b,26c, and26dare provided at the lower end of the rotor magnet23. Therefore, it is possible to maintain the detection accuracy of the magnetic field by the magnetic sensor52while further improving the output of the motor10by the second non-radially magnetized portions26a,26b,26c, and26d. In addition, the magnetic sensor52is located on the radially inner side of the lower end of the rotor magnet23according to the present embodiment. Therefore, the magnetic field at the lower end of the rotor magnet23can be more easily detected by the magnetic sensor52. Therefore, the detection accuracy of the magnetic sensor52can be further improved. In addition, the lower end of the rotor magnet23is located below the lower end of the stator core31according to the present embodiment. Therefore, even if the void portion27is provided as the non-magnetized portion at the lower end of the rotor magnet23, it is possible to suppress a decrease in the amount of magnetic flux flowing between the rotor20and the stator30. Therefore, it is possible to suppress the decrease in the output of the motor10. The present invention is not limited to the above-described embodiment, and can also employ the following configurations. The Halbach array applied to the rotor magnet is not particularly limited as long as a Halbach array increases the magnetic field intensity on the radially outer side (one side in the radial direction). For example, a Halbach array in which the second non-radially magnetized portions26a,26b,26c, and26dare not provided may be applied to the Halbach array of the above-described embodiment for the rotor magnet. Magnetized portions adjacent to each other in the circumferential direction may be arranged with a gap therebetween. The magnetized portions are not necessarily separate members. In this case, a rotor magnet may be a single member. A lower end (one side in the axial direction) of the rotor magnet may be located at the same position in the axial direction as a lower end of a rotor core, or may be located at the same position in the axial direction as a lower end of a stator core. The non-magnetized portion is not particularly limited as long as being provided in the axial portion of the rotor magnet where the magnetic field is detected by the magnetic sensor. In the above-described embodiment, the non-magnetized portion may be void portions provided below the second non-radially magnetized portions26a,26b,26c, and26d. In this case, the void portions may be provided instead of the void portions27provided below the first non-radially magnetized portions25aand25b, or may be provided together with the void portions27. The number of non-magnetized portions is not particularly limited as long as the number is one or more. An axial dimension of a first non-radially magnetized portion may be the same as an axial dimension of a radially magnetized portion. In this case, a void portion as a non-magnetized portion may be provided below (one side in the axial direction of) the first non-radially magnetized portion by axially shifting the first non-radially magnetized portion with respect to the radially magnetized portion. According to such a configuration, all magnetized portions can have the same shape, and thus, it is easy to manufacture a plurality of magnetized portions. The position of the magnetic sensor is not particularly limited as long as being located on the other side in the radial direction of the rotor magnet. The magnetic sensor may be entirely arranged at an axial position different from the rotor magnet. For example, the magnetic sensor52of the above-described embodiment may be located below the position illustrated inFIG.4and located below the rotor magnet23. The magnetic sensor may be located on the other side in the radial direction of the central portion of the rotor magnet in the axial direction. The number of magnetic sensors is not particularly limited as long as the number is one or more. The magnetic sensor may be a magnetoresistive element. In the above-described embodiment, the inner-rotor motor10is adopted as the configuration in which one side in the radial direction is the radially outer side and the other side in the radial direction is the radially inner side, but the present invention is not limited thereto. It may be configured such that one side in the radial direction is a radially inner side, and the other side in the radial direction is a radially outer side. In this case, an outer-rotor motor can be adopted. An application of the motor according to the present disclosure is not particularly limited. The motor may be installed on a vehicle or the like, for example. Note that each configuration described in the present specification can be properly combined within a range having no contradiction. Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises. While preferred embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims. | 44,033 |
11863023 | EMBODIMENTS FOR CARRYING OUT THE INVENTION The embodiments will be described below with reference to the drawings. Parts of the embodiments functionally or structurally corresponding to each other or associated with each other will be denoted by the same reference numbers or by reference numbers which are different in the hundreds place from each other. The corresponding or associated parts may refer to the explanation in the other embodiments. The rotating electrical machine in the embodiments is configured to be used, for example, as a power source for vehicles. The rotating electrical machine may, however, be used widely for industrial, automotive, domestic, office automation, or game applications. In the following embodiments, the same or equivalent parts will be denoted by the same reference numbers in the drawings, and explanation thereof in detail will be omitted. First Embodiment The rotating electrical machine10in this embodiment is a synchronous polyphase ac motor having an outer rotor structure (i.e., an outer rotating structure). The outline of the rotating electrical machine10is illustrated inFIGS.1to5.FIG.1is a perspective longitudinal sectional view of the rotating electrical machine10.FIG.2is a longitudinal sectional view along the rotating shaft11of the rotating electrical machine10.FIG.3is a traverse sectional view (i.e., sectional view taken along the line III-III inFIG.2) of the rotating electrical machine10perpendicular to the rotating shaft11.FIG.4is a partially enlarged sectional view ofFIG.3.FIG.5is an exploded view of the rotating electrical machine10.FIG.3omits hatching showing a section except the rotating shaft11for the sake of simplicity of the drawings. In the following discussion, a lengthwise direction of the rotating shaft11will also be referred to as an axial direction. A radial direction from the center of the rotating shaft11will be simply referred to as a radial direction. A direction along a circumference of the rotating shaft11about the center thereof will be simply referred to as a circumferential direction. The rotating electrical machine10includes the bearing unit20, the housing30, the rotor40, the stator50, and the inverter unit60. These members are arranged coaxially with each other together with the rotating shaft11and assembled in a given sequence to complete the rotating electrical machine10. The rotating electrical machine10in this embodiment is equipped with the rotor40working as a magnetic field-producing unit or a field system and the stator50working as an armature and engineered as a revolving-field type rotating electrical machine. The bearing unit20includes two bearings21and22arranged away from each other in the axial direction and the retainer23which retains the bearings21and22. The bearings21and22are implemented by, for example, radial ball bearings each of which includes the outer race25, the inner race26, and a plurality of balls27disposed between the outer race25and the inner race26. The retainer23is of a cylindrical shape. The bearings21and22are disposed radially inside the retainer23. The rotating shaft11and the rotor40are retained radially inside the bearings21and22to be rotatable. The bearings21and22are used as a set of bearings to rotatably retain the rotating shaft11. Each of the bearings21and22holds the balls27using a retainer, not shown, to keep a pitch between the balls27constant. Each of the bearings21and22is equipped with seals on axially upper and lower ends of the retainer and also has non-conductive grease (e.g., non-conductive urease grease) installed inside the seals. The position of the inner race26is mechanically secured by a spacer to exert constant inner precompression on the inner race26in the form of a vertical convexity. The housing30includes the cylindrical peripheral wall31. The peripheral wall31has a first end and a second end opposed to each other in an axial direction thereof. The peripheral wall31has the end surface32on the first end and the opening33in the second end. The opening33occupies the entire area of the second end. The end surface32has formed in the center thereof the circular hole34. The bearing unit20is inserted into the hole34and fixed using a fastener, such as a screw or a rivet. The hollow cylindrical rotor40and the hollow cylindrical stator50are disposed in an inner space defined by the peripheral wall31and the end surface32within the housing30. In this embodiment, the rotating electrical machine10is of an outer rotor type, so that the stator50is arranged radially inside the cylindrical rotor40within the housing30. The rotor40is retained in a cantilever form by a portion of the rotating shaft11close to the end surface32in the axial direction. The rotor40includes the hollow cylindrical magnetic holder41and the annular magnet unit42disposed radially inside the magnet holder41. The magnet holder41is of substantially a cup-shape and works as a magnet holding member. The magnet holder41includes the cylinder43, the attaching portion44which is of a cylindrical shape and smaller in diameter than the cylinder43, and the intermediate portion45connecting the cylinder43and the attaching portion44together. The cylinder43has the magnet unit42secured to an inner peripheral surface thereof. The magnet holder41is made of cold rolled steel (SPCC), forging steel, or carbon fiber reinforced plastic (CFRP) which have a required degree of mechanical strength. The rotating shaft11passes through the through-hole44aof the attaching portion44. The attaching portion44is secured to a portion of the rotating shaft11disposed inside the through-hole44a. In other words, the magnet holder41is secured to the rotating shaft11through the attaching portion44. The attaching portion44may preferably be joined to the rotating shaft11using concavities and convexities, such as a spline joint or a key joint, welding, or crimping, so that the rotor40rotates along with the rotating shaft11. The bearings21and22of the bearing unit20are secured radially outside the attaching portion44. The bearing unit20is, as described above, fixed on the end surface32of the housing30, so that the rotating shaft11and the rotor40are retained by the housing30to be rotatable. The rotor40is, thus, rotatable within the housing30. The rotor40is equipped with the attaching portion44arranged only one of ends thereof opposed to each other in the axial direction of the rotor40. This cantilevers the rotor40on the rotating shaft11. The attaching portion44of the rotor40is rotatably retained at two points of supports using the bearings21and22of the bearing unit20which are located away from each other in the axial direction. In other words, the rotor40is held to be rotatable using the two bearings21and22which are separate at a distance away from each other in the axial direction on one of the axially opposed ends of the magnet holder41. This ensures the stability in rotation of the rotor40even though the rotor40is cantilevered on the rotating shaft11. The rotor40is retained by the bearings21and22at locations which are away from the center intermediate between the axially opposed ends of the rotor40in the axial direction thereof. The bearing22of the bearing unit20which is located closer to the center of the rotor40(a lower one of the bearings21and22in the drawings) is different in dimension of a gap between each of the outer race25and the inner race and the balls27from the bearing21which is located farther away from the center of the rotor40(i.e., an upper one of the bearings21and22). For instance, the bearing22closer to the center of the rotor40is greater in the dimension of the gap from the bearing21. This minimizes adverse effects on the bearing unit20which arise from deflection of the rotor40or mechanical vibration of the rotor40due to imbalance resulting from parts tolerance at a location close to the center of the rotor40. Specifically, the bearing22closer to the center of the rotor40is engineered to have dimensions of the gaps or plays increased using precompression, thereby absorbing the vibration generating in the cantilever structure. The precompression may be provided by either fixed position preload or constant pressure preload. In the case of the fixed position preload, the outer race25of each of the bearings21and22is joined to the retainer23using press-fitting or welding. The inner race26of each of the bearings21and22is joined to the rotating shaft11by press-fitting or welding. The precompression may be created by placing the outer race25of the bearing21away from the inner race26of the bearing21in the axial direction or alternatively placing the outer race25of the bearing22away from the inner race26of the bearing22in the axial direction. In the case of the constant pressure preload, a preload spring, such as a wave washer24, is arranged between the bearing22and the bearing21to create the preload directed from a region between the bearing22and the bearing21toward the outer race25of the bearing22in the axial direction. In this case, the inner race26of each of the bearing21and the bearing22is joined to the rotating shaft11using press fitting or bonding. The outer race25of the bearing21or the bearing22is arranged away from the outer race25through a given clearance. This structure exerts pressure, as produced by the preload spring, on the outer race25of the bearing22to urge the outer race25away from the bearing21. The pressure is then transmitted through the rotating shaft11to urge the inner race26of the bearing21toward the bearing22, thereby bringing the outer race25of each of the bearings21and22away from the inner race26thereof in the axial direction to exert the preload on the bearings21and22in the same way as the fixed position preload. The constant pressure preload does not necessarily need to exert the spring pressure, as illustrated inFIG.2, on the outer race25of the bearing22, but may alternatively be created by exerting the spring pressure on the outer race25of the bearing21. The exertion of the preload on the bearings21and22may alternatively be achieved by placing the inner race26of one of the bearings21and22away from the rotating shaft11through a given clearance therebetween and joining the outer race25of each of the bearings21and22to the retainer23using press-fitting or bonding. Further, in the case where the pressure is created to bring the inner race26of the bearing21away from the bearing22, such pressure is preferably additionally exerted on the inner race26of the bearing22away from the bearing21. Conversely, in the case where the pressure is created to bring the inner race26of the bearing21close to the bearing22, such pressure is preferably additionally exerted on the inner race26of the bearing22to bring it close to the bearing21. In a case where the rotating electrical machine10is used as a power source for a vehicle, there is a risk that mechanical vibration having a component oriented in a direction in which the preload is created may be exerted on the preload generating structure or that a direction in which the force of gravity acts on an object to which the preload is applied may be changed. In order to alleviate such a problem, the fixed position preload is preferably used in the case where the rotating electrical machine10is mounted in the vehicle. The intermediate portion45includes the annular inner shoulder49aand the annular outer shoulder49b. The outer shoulder49bis arranged outside the inner shoulder49ain the radial direction of the intermediate portion45. The inner shoulder49aand the outer shoulder49bare separate from each other in the axial direction of the intermediate portion45. This layout results in a partial overlap between the cylinder43and the attaching portion44in the radial direction of the intermediate portion45. In other words, the cylinder43protrudes outside a base end portion (i.e., a lower portion, as viewed in the drawing) of the attaching portion44in the axial direction. The structure in this embodiment enables the rotor40to be retained by the rotating shaft11at a location closer to the center of gravity of the rotor40than a case where the intermediate portion45is shaped to be flat without any shoulder, thereby ensuring the stability in operation of the rotor40. In the above described structure of the intermediate portion45, the rotor40has the annular bearing housing recess46which is formed in an inner portion of the intermediate portion45and radially surrounds the attaching portion44. The bearing housing recess46has a portion of the bearing unit20disposed therein. The rotor40also has the coil housing recess47which is formed in an outer portion of the intermediate portion45and radially surrounds the bearing housing recess46. The coil housing recess47has disposed therein the coil end54of the stator winding51of the stator50, which will be described later in detail. The housing recesses46and47are arranged adjacent each other in the axial direction. In other words, a portion of the bearing unit20is laid to overlap the coil end54of the stator winding51in the axial direction. This enables the rotating electrical machine10to have a length decreased in the axial direction. The intermediate portion45extends or overhangs outward from the rotating shaft11in the radial direction. The intermediate portion45is equipped with a contact avoider which extends in the axial direction and avoids a physical contact with the coil end54of the stator winding51of the stator50. The intermediate portion45will also be referred to as an overhang. The coil end54may be bent radially inwardly or outwardly to have a decreased axial dimension, thereby enabling the axial length of the stator50to be decreased. A direction in which the coil end54is bent is preferably determined depending upon installation thereof in rotor40. In the case where the stator50is installed radially inside the rotor40, a portion of the coil end54which is inserted into the rotor40is preferably bent radially inwardly. A coil end opposite the coil end54may be bent either inwardly or outwardly, but is preferably bent to an outward side where there is an enough space in terms of the production thereof. The magnet unit42working as a magnetic portion is made up of a plurality of permanent magnets which are disposed radially inside the cylinder43to have different magnetic poles arranged alternately in a circumferential direction thereof. The magnet unit42, thus, has a plurality of magnetic poles arranged in the circumferential direction. The magnet unit42will also be described later in detail. The stator50is arranged radially inside the rotor40. The stator50includes the stator winding51wound in a substantially cylindrical (annular) form and the stator core52used as a base member arranged radially inside the stator winding51. The stator winding51is arranged to face the annular magnet unit42through a given air gap therebetween. The stator winding51includes a plurality of phase windings each of which is made of a plurality of conductors which are arranged at a given pitch away from each other in the circumferential direction and joined together. In this embodiment, two three-phase windings: one including a U-phase winding, a V-phase winding, and a W-phase winging and the other including an X-phase winding, a Y-phase winding, and a Z-phase winding are used to complete the stator winding51as a six-phase winding. The stator core52is formed by an annular stack of magnetic steel plates made of soft magnetic material and mounted radially inside the stator winding51. The magnetic steel plates are, for example, silicon nitride steel plates made by adding a small percent (e.g., 3%) of silicon nitride to iron. The stator winding51corresponds to an armature winding. The stator core52corresponds to an armature core. The stator winding51overlaps the stator core52in the radial direction and includes the coil side portion53disposed radially outside the stator core52and the coil ends54and55overhanging at ends of the stator core52in the axial direction. The coil side portion53faces the stator core52and the magnet unit42of the rotor40in the radial direction. The stator50is arranged inside the rotor40. The coil end54that is one (i.e., an upper one, as viewed in the drawings) of the axially opposed coil ends54and55and arranged close to the bearing unit20is disposed in the coil housing recess47defined by the magnet holder41of the rotor40. The stator50will also be described later in detail. The inverter unit60includes the unit base61secured to the housing30using fasteners, such as bolts, and a plurality of electrical components62mounted on the unit base61. The unit base61is made from, for example, carbon fiber reinforced plastic (CFRP). The unit base61includes the end plate63secured to an edge of the opening33of the housing30and the casing64which is formed integrally with the end plate63and extends in the axial direction. The end plate63has the circular opening65formed in the center thereof. The casing64extends upward from a peripheral edge of the opening65. The stator50is arranged on an outer peripheral surface of the casing64. Specifically, an outer diameter of the casing64is selected to be identical with or slightly smaller than an inner diameter of the stator core52. The stator core52is attached to the outer side of the casing64to complete a unit made up of the stator50and the unit base61. The unit base61is secured to the housing30, so that the stator50is unified with the housing50in a condition where the stator core52is installed on the casing64. The stator core52may be bonded, shrink-fit, or press-fit on the unit base61, thereby eliminating positional shift of the stator core52relative to the unit base61both in the circumferential direction and in the axial direction. The casing64has a radially inner storage space in which the electrical components62are disposed. The electrical components62are arranged to surround the rotating shaft11within the storage space. The casing64functions as a storage space forming portion. The electrical components62include the semiconductor modules66, the control board67, and the capacitor module68which constitute an inverter circuit. The unit base61serves as a stator holder (i.e., an armature holder) which is arranged radially inside the stator50and retains the stator50. The housing30and the unit base61define a motor housing for the rotating electrical machine10. In the motor housing, the retainer23is secured to a first end of the housing30which is opposed to a second end of the housing30through the rotor40in the axial direction. The second end of the housing30and the unit base61are joined together. For instance, in an electric-powered vehicle, such as an electric automobile, the motor housing is attached to a side of the vehicle to install the rotating electrical machine10in the vehicle. The inverter unit60will be also be described usingFIG.6that is an exploded view in addition toFIGS.1to5. The casing64of the unit base61includes the cylinder71and the end surface72that is one of ends of the cylinder71which are opposed to each other in the axial direction of the cylinder71(i.e., the end of the casing64close to the bearing unit20). The end of the cylinder71opposed to the end surface72in the axial direction is shaped to fully open to the opening65of the end plate63. The end surface72has formed in the center thereof the circular hole73through which the rotating shaft11is insertable. The hole73has fitted therein the sealing member171which hermetically seals an air gap between the hole73and the outer periphery of the rotating shaft11. The sealing member171is preferably implemented by, for example, a resinous slidable seal. The cylinder71of the casing64serves as a partition which isolates the rotor40and the stator50arranged radially outside the cylinder71from the electrical components62arranged radially inside the cylinder71. The rotor40, the stator50, and the electrical components62are arranged radially inside and outside the cylinder71. The electrical components62are electrical devices making up the inverter circuit equipped with a motor function and a generator function. The motor function is to deliver electrical current to the phase windings of the stator winding51in a given sequence to turn the rotor40. The generator function is to receive a three-phase ac current flowing through the stator winding51in response to the rotation of the rotating shaft11and generate and output electrical power. The electrical components62may be engineered to perform either one of the motor function and the generator function. In a case where the rotating electrical machine10is used as a power source for a vehicle, the generator function serves as a regenerative function to output a regenerated electrical power. Specifically, the electrical components62, as demonstrated inFIG.4, include the hollow cylindrical capacitor module68arranged around the rotating shaft11and the semiconductor modules66mounted on the capacitor module68. The capacitor module68has a plurality of smoothing capacitors68aconnected in parallel to each other. Specifically, each of the capacitors68ais implemented by a stacked-film capacitor which is made of a plurality of film capacitors stacked in a trapezoidal shape in cross section. The capacitor module68is made of the twelve capacitors68aarranged in an annular shape. The capacitors68amay be produced by preparing a long film which has a given width and is made of a stack of films and cutting the long film into isosceles trapezoids each of which has a height identical with the width of the long film and whose short bases and long bases are alternately arranged. Electrodes are attached to the thus produced capacitor devices to complete the capacitors68a. The semiconductor module66includes, for example, a semiconductor switch, such as a MOSFET or an IGBT and is of substantially a planar shape. In this embodiment, the rotating electrical machine10is, as described above, equipped with two sets of three-phase windings and has the inverter circuits, one for each set of the three-phase windings. The electrical components62, therefore, include a total of twelve semiconductor modules66which are arranged in an annular form to make up the semiconductor module group66A. The semiconductor modules66are interposed between the cylinder71of the casing64and the capacitor module68. The semiconductor module group66A has an outer peripheral surface placed in contact with an inner peripheral surface of the cylinder71. The semiconductor module group66A also has an inner peripheral surface placed in contact with an outer peripheral surface of the capacitor module68. This causes heat, as generated in the semiconductor modules66, to be transferred to the end plate63through the casing64, so that it is dissipated from the end plate63. The semiconductor module group66A preferably has the spacers69disposed radially outside the outer peripheral surface thereof, i.e., between the semiconductor modules66and the cylinder71. A combination of the capacitor modules68is so arranged as to have a regular dodecagonal section extending perpendicular to the axial direction thereof, while the inner periphery of the cylinder71has a circular transverse section. The spacers69are, therefore, each shaped to have a flat inner peripheral surface and a curved outer peripheral surface. The spacers69may alternatively be formed integrally with each other in an annular shape and disposed radially outside the semiconductor module group66A. The spacers69are highly thermally conductive and made of, for example, metal, such as aluminum or heat dissipating gel sheet. The inner periphery of the cylinder71may alternatively be shaped to have a dodecagonal transverse section like the capacitor modules68. In this case, the spacers69are each preferably shaped to have a flat inner peripheral surface and a flat outer peripheral surface. In this embodiment, the cylinder71of the casing64has formed therein the coolant path74through which coolant flows. The heat generated in the semiconductor modules66is also released to the coolant flowing in the coolant path74. In other words, the casing64is equipped with a cooling mechanism. The coolant path74is, as clearly illustrated inFIGS.3and4, formed in an annular shape and surrounds the electrical components62(i.e., the semiconductor modules66and the capacitor module68). The semiconductor modules66are arranged along the inner peripheral surface of the cylinder71. The coolant path74is laid to overlap the semiconductor modules66in the radial direction. The stator50is arranged outside the cylinder71. The electrical components62are arranged inside the cylinder71. This layout causes the heat to be transferred from the stator50to the outer side of the cylinder71and also transferred from the electrical components62(e.g., the semiconductor modules66) to the inner side of the cylinder71. It is possible to simultaneously cool the stator50and the semiconductor modules66, thereby facilitating dissipation of thermal energy generated by heat-generating members of the rotating electrical machine10. Further, at least one of the semiconductor modules66which constitute part or all of the inverter circuits serving to energize the stator winding51to drive the rotating electrical machine is arranged in a region surrounded by the stator core52disposed radially outside the cylinder71of the casing64. Preferably, one of the semiconductor modules66may be arranged fully inside the region surrounded by the stator core52. More preferably, all the semiconductor modules66may be arranged fully in the region surrounded by the stator core52. At least a portion of the semiconductor modules66is arranged in a region surrounded by the coolant path74. Preferably, all the semiconductor modules66may be arranged in a region surrounded by the yoke141. The electrical components62include the insulating sheet75disposed on one of axially opposed end surfaces of the capacitor module68and the wiring module76disposed on the other end surface of the capacitor module68. The capacitor module68has two axially-opposed end surfaces: a first end surface and a second end surface. The first end surface of the capacitor module68closer to the bearing unit20faces the end surface72of the casing64and is laid on the end surface72through the insulating sheet75. The second end surface of the capacitor module68closer to the opening65has the wiring module76mounted thereon. The wiring module76includes the resin-made circular plate-shaped body76aand a plurality of bus bars76band76cembedded in the body76a. The bus bars76band76celectrically connect the semiconductor modules66and the capacitor module68together. Specifically, the semiconductor modules66are equipped with the connecting pins66aextending from axial ends thereof. The connecting pins66aconnect with the bus bars76bradially outside the body76a. The bus bars76cextend away from the capacitor module68radially outside the body76aand have top ends connecting with the wiring members79(seeFIG.2). The capacitor module68, as described above, has the insulating sheet75mounted on the first end surface thereof. The capacitor module68also has the wiring module76mounted on the second end surface thereof. The capacitor module68, therefore, has two heat dissipating paths which extend from the first and second end surfaces of the capacitor module68to the end surface72and the cylinder71. Specifically, the heat dissipating path is defined which extends from the first end surface to the end surface72. The heat dissipating path is defined which extends from the second end surface to the cylinder71. This enables the heat to be released from the end surfaces of the capacitor module68other than the outer peripheral surface on which the semiconductor modules66are arranged. In other words, it is possible to dissipate the heat not only in the radial direction, but also in the axial direction. The capacitor module68is of a hollow cylindrical shape and has the rotating shaft11arranged therewithin at a given interval away from the inner periphery of the capacitor module68, so that heat generated by the capacitor module68will be dissipated from the hollow cylindrical space. The rotation of the rotating shaft11usually produces a flow of air, thereby enhancing cooling effects. The wiring module76has the disc-shaped control board67attached thereto. The control board67includes a printed circuit board (PCB) on which given wiring patterns are formed and also has ICs and the control device77mounted thereon. The control device77serves as a controller and is made of a microcomputer. The control board67is secured to the wiring module76using fasteners, such as screws. The control board67has formed in the center thereof the hole67athrough which the rotating shaft11passes. The wiring module76has a first surface and a second surface opposed to each other in the axial direction, that is, a thickness-wise direction of the wiring module76. The first surface faces the capacitor module68. The wiring module76has the control board67mounted on the second surface thereof. The bus bars76cof the wiring module76extend from one of surfaces of the control board67to the other. The control board67may have cut-outs for avoiding physical interference with the bus bars76c. For instance, the control board67may have the cut-outs formed in portions of the circular outer edge thereof. The electrical components62are, as described already, arranged inside the space surrounded by the casing64. The housing30, the rotor40, and the stator50are disposed outside the space in the form of layers. This structure serves to shield against electromagnetic noise generated in the inverter circuits. Specifically, the inverter circuit works to control switching operations of the semiconductor modules66in a PWM control mode using a given carrier frequency. The switching operations usually generate electromagnetic noise against which the housing30, the rotor40, and the stator50which are arranged outside the electrical components62shield. Further, at least a portion of the semiconductor modules66is arranged inside the region surrounded by the stator core52located radially outside the cylinder71of the casing64, thereby minimizing adverse effects of magnetic flux generated by the semiconductor modules66on the stator winding51as compared with a case where the semiconductor modules66and the stator winding51are arranged without the stator core52interposed therebetween. The magnetic flux created by the stator winding51also hardly affects the semiconductor modules66. It is more effective that the whole of the semiconductor modules66are located in the region surrounded by the stator core52disposed radially outside the cylinder71of the casing64. When at least a portion of the semiconductor modules66is surrounded by the coolant path74, it offers a beneficial advantage that the heat produced by the stator winding51or the magnet unit42is prevented from reaching the semiconductor modules66. The cylinder71has the through-holes78which are formed near the end plate63and through which the wiring members79(seeFIG.2) pass to electrically connect the stator50disposed outside the cylinder71and the electrical components62arranged inside the cylinder71. The wiring members79, as illustrated inFIG.2, connect with ends of the stator winding51and the bus bars76cof the wiring module76using crimping or welding techniques. The wiring members79are implemented by, for example, bus bars whose joining surfaces are preferably flattened. A single through-hole78or a plurality of through-holes78are preferably provided. This embodiment has two through-holes78. The use of the two through-holes78facilitates the ease with which terminals extending from the two sets of the three-phase windings are connected by the wiring members79, and is suitable for achieving multi-phase wire connections. The rotor40and the stator50are, as described already inFIG.4, arranged within the housing30in this order in a radially inward direction. The inverter unit60is arranged radially inside the stator50. If a radius of the inner periphery of the housing30is defined as d, the rotor40and the stator50are located radially outside a distance of d×0.705 away from the center of rotation of the rotor40. If a region located radially inside the inner periphery of the stator50(i.e., the inner circumferential surface of the stator core52) is defined as a first region X1, and a region radially extending from the inner periphery of the stator50to the housing30is defined as a second region X2, an area of a transverse section of the first region X1is set greater than that of the second region X2. As viewed in a region where the magnet unit42of the rotor40overlaps the stator winding51, the volume of the first region X1is larger than that of the second region X2. The rotor40and the stator50are fabricated as a magnetic circuit component assembly. In the housing30, the first region X1which is located radially inside the inner peripheral surface of the magnetic circuit component assembly is larger in volume than the region X2which lies between the inner peripheral surface of the magnetic circuit component assembly and the housing30in the radial direction. Next, the structures of the rotor40and the stator50will be described below in more detail. Typical rotating electrical machines are known which are equipped with a stator with an annular stator core which is made of a stack of steel plates and has a stator winding wound in a plurality of slots arranged in a circumferential direction of the stator core. Specifically, the stator core has teeth extending in a radial direction thereof at a given interval away from a yoke. Each slot is formed between the two radially adjacent teeth. In each slot, a plurality of conductors are arranged in the radial direction in the form of layers to form the stator winding. However, the above described stator structure has a risk that when the stator winding is energized, an increase in magnetomotive force in the stator winding may result in magnetic saturation in the teeth of the stator core, thereby restricting torque density in the rotating electrical machine. In other words, rotational flux, as created by the energization of the stator winding of the stator core, is thought of as concentrating on the teeth, which has a risk of causing magnetic saturation. Generally, IPM (Interior Permanent Magnet) rotors are known which have a structure in which permanent magnets are arranged on a d-axis of a d-q axis coordinate system, and a rotor core is placed on a q-axis of the d-q axis coordinate system. Excitation of a stator winding near the d-axis will cause an excited magnetic flux to flow from a stator to a rotor according to Fleming's rules. This causes magnetic saturation to occur widely in the rotor core on the q-axis. FIG.7is a torque diagrammatic view which demonstrates a relationship between an ampere-turn (AT) representing a magnetomotive force created by the stator winding and a torque density (Nm/L). A broken line indicates characteristics of a typical IPM rotor-rotating electrical machine.FIG.7shows that in the typical rotating electrical machine, an increase in magnetomotive force in the stator will cause magnetic saturation to occur at two places: the tooth between the slots and the q-axis rotor (i.e., the rotor core on the q-axis), thereby restricting an increase in torque. In this way, a design value of the ampere-turn is restricted at A1in the typical rotating electrical machine. In order to alleviate the above problem in this embodiment, the rotating electrical machine10is designed to have an additional structure, as will be described below, in order to eliminate the restriction arising from the magnetic saturation. Specifically, as a first measure, the stator50is designed to have a slot-less structure for eliminating the magnetic saturation occurring in the teeth of the stator core of the stator and also to use an SPM (Surface Permanent Magnet) rotor for eliminating the magnetic saturation occurring in a q-axis core of the IPM rotor. The first measure serves to eliminate the above described two places where the magnetic saturation occurs, but however, may result in a decrease in torque in a low-current region (see an alternate long and short dash line inFIG.7). In order to alleviate this problem, as a second measure, a polar anisotropy structure is employed to increase a magnetic path of magnets in the magnet unit42of the rotor40to enhance a magnetic force in order to increase a magnetic flux in the SPM rotor to minimize the torque decrease. Additionally, as a third measure, a flattened conductor structure is employed to decrease a thickness of conductors of the coil side portion53of the stator winding51in the radial direction of the stator50for compensating for the torque decrease. The above magnetic force-enhanced polar anisotropy structure is thought of as resulting in a flow of large eddy current in the stator winding51facing the magnet unit42. The third measure is, however, to employ the flattened conductor structure in which the conductors have a decreased thickness in the radial direction, thereby minimizing the generation of the eddy current in the stator winding51in the radial direction. In this way, the above first to third structures are, as indicated by a solid line inFIG.7, expected to greatly improve the torque characteristics using high-magnetic force magnets and also alleviate a risk of generation of a large eddy current resulting from the use of the high-magnetic force magnets. Additionally, as a fourth measure, a magnet unit is employed which has a polar anisotropic structure to create a magnetic density distribution approximating a sine wave. This increases a sine wave matching percentage using pulse control, as will be described later, to enhance the torque and also results in a moderate change in magnetic flux, thereby minimizing an eddy-current loss (i.e., a copper loss caused by eddy current) as compared with radial magnets. The sine wave matching percentage will be described below. The sine wave matching percentage may be derived by comparing a waveform, a cycle, and a peak value of a surface magnetic flux density distribution measured by actually moving a magnetic flux probe on a surface of a magnet with those of a sine wave. The since wave matching percentage is given by a percentage of an amplitude of a primary waveform that is a waveform of a fundamental wave in a rotating electrical machine to that of the actually measured waveform, that is, an amplitude of the sum of the fundamental wave and a harmonic component. An increase in the sine wave matching percentage will cause the waveform in the surface magnetic flux density distribution to approach the waveform of the sine wave. When an electrical current of a primary sine wave is delivered by an inverter to a rotating electrical machine equipped with magnets having an improved sine wave matching percentage, it will cause a large degree of torque to be produced, combined with the fact that the waveform in the surface magnetic flux density distribution of the magnet is close to the waveform of a sine wave. The surface magnetic flux density distribution may alternatively be derived using electromagnetic analysis according to Maxwell's equations. As a fifth measure, the stator winding51is designed to have a conductor strand structure made of a bundle of wires. In the conductor strand structure of the stator winding51, the wires are connected parallel to each other, thus enabling a high current or large amount of current to flow in the stator winding51and also minimizing an eddy current occurring in the conductors widened in the circumferential direction of the stator50more effectively than the third measure in which the conductors are flattened in the radial direction because each of the wires has a decreased transverse sectional area. The use of the bundle of the wires will cancel an eddy current arising from magnetic flux occurring according to Ampere's circuital law in response to the magnetomotive force produced by the conductors. The use of the fourth and fifth measures minimizes the eddy-current loss resulting from the high magnetic force produced by the high-magnetic force magnets provided by the second measure and also enhance the torque. The slot-less structure of the stator50, the flattened conductor structure of the stator winding51, and the polar anisotropy structure of the magnet unit42will be described below. The slot-less structure of the stator50and the flattened conductor structure of the stator winding51will first be discussed.FIG.8is a transverse sectional view illustrating the rotor40and the stator50.FIG.9is a partially enlarged view illustrating the rotor40and the stator50inFIG.8.FIG.10is a transverse sectional view of the stator50taken along the line X-X inFIG.11.FIG.11is a longitudinal sectional view of the stator50.FIG.12is a perspective view of the stator winding51.FIGS.8and9indicate directions of magnetization of magnets of the magnet unit42using arrows. The stator core52is, as clearly illustrated inFIGS.8to11, of a cylindrical shape and made of a plurality of magnetic steel plates stacked in the axial direction of the stator core52to have a given thickness in a radial direction of the stator core52. The stator winding51is mounted on the outer periphery of the stator core52which faces the rotor40. The outer peripheral surface of the stator core52facing the rotor40serves as a conductor mounting portion (i.e., a conductor area). The outer peripheral surface of the stator core52is shaped as a curved surface without any irregularities. A plurality of conductor groups81are arranged on the outer peripheral surface of the stator core52at given intervals away from each other in the circumferential direction of the stator core52. The stator core52functions as a back yoke that is a portion of a magnetic circuit working to rotate the rotor40. The stator50is designed to have a structure in which a tooth (i.e., a core) made of a soft magnetic material is not disposed between a respective two of the conductor groups81arranged adjacent each other in the circumferential direction (i.e., the slot-less structure). In this embodiment, a resin material of the sealing member57is disposed in the space or gap56between a respective adjacent two of the conductor groups81. In other words, the stator50has a conductor-to-conductor member which is disposed between the conductor groups81arranged adjacent each other in the circumferential direction of the stator50and made of a non-magnetic material. The conductor-to-conductor members serve as the sealing members57. Before the sealing members57are placed to seal the gaps56, the conductor groups81are arranged in the circumferential direction radially outside the stator core52at a given interval away from each other through the gaps56that are conductor-to-conductor regions. This makes up the slot-less structure of the stator50. In other words, each of the conductor groups81is, as described later in detail, made of two conductors82. An interval between a respective two of the conductor groups81arranged adjacent each other in the circumferential direction of the stator50is occupied only by a non-magnetic material. The non-magnetic material, as referred to herein, includes a non-magnetic gas, such as air, or a non-magnetic liquid. In the following discussion, the sealing members57will also be referred to as conductor-to-conductor members. The structure, as referred to herein, in which the teeth are respectively disposed between the conductor groups81arrayed in the circumferential direction means that each of the teeth has a given thickness in the radial direction and a given width in the circumferential direction of the stator50, so that a portion of the magnetic circuit, that is, a magnet magnetic path lies between the adjacent conductor groups81. In contrast, the structure in which no tooth lies between the adjacent conductor groups81means that there is no magnetic circuit between the adjacent conductor groups81. The stator winding (i.e., the armature winding)51, as illustrated inFIG.10, has a given thickness T2(which will also be referred to below as a first dimension) and a width W2(which will also be referred to below as a second dimension). The thickness T2is given by a minimum distance between an outer side surface and an inner side surface of the stator winding51which are opposed to each other in the radial direction of the stator50. The width W2is given by a dimension of a portion of the stator winding51which functions as one of multiple phases (i.e., the U-phase, the V-phase, the W-phase, the X-phase, the Y-phase, and the Z-phase in this embodiment) of the stator winding51in the circumferential direction. Specifically, in a case where the two conductor groups81arranged adjacent each other in the circumferential direction inFIG.10serve as one of the three phases, for example, the U-phase winding, a distance between circumferentially outermost ends of the two circumferentially adjacent conductor groups81is the width W2. The thickness T2is smaller than the width W2. The thickness T2is preferably set smaller than the sum of widths of the two conductor groups81within the width W2. If the stator winding51(more specifically, the conductor82) is designed to have a true circular transverse section, an oval transverse section, or a polygonal transverse section, the cross section of the conductor82taken in the radial direction of the stator50may be shaped to have a maximum dimension W12in the radial direction of the stator50and a maximum dimension W11in the circumferential direction of the stator50. The stator winding51is, as can be seen inFIGS.10and11, sealed by the sealing members57which are formed by a synthetic resin mold. Specifically, the stator winding51and the stator core52are put in a mould together when the sealing members57are moulded by the resin. The resin may be considered as a non-magnetic material or an equivalent thereof whose Bs (saturation magnetic flux density) is zero. As a transverse section is viewed inFIG.10, the sealing members57are provided by placing synthetic resin in the gaps56between the conductor groups81. The sealing members57serve as insulators arranged between the conductor groups81. In other words, each of the sealing members57functions as an insulator in one of the gaps56. The sealing members57occupy a region which is located radially outside the stator core52, and includes all the conductor groups81, in other words, which is defined to have a dimension larger than that of each of the conductor groups81in the radial direction. As a longitudinal section is viewed inFIG.11, the sealing members57lie to occupy a region including the turns84of the stator winding51. Radially inside the stator winding51, the sealing members57lie in a region including at least a portion of the axially opposed ends of the stator core52. In this case, the stator winding51is fully sealed by the resin except for the ends of each phase winding, i.e., terminals joined to the inverter circuits. The structure in which the sealing members57are disposed in the region including the ends of the stator core52enables the sealing members57to compress the stack of the steel plates of the stator core52inwardly in the axial direction. In other words, the sealing members57work to firmly retain the stack of the steel plates of the stator core52. In this embodiment, the inner peripheral surface of the stator core52is not sealed using resin, but however, the whole of the stator core52including the inner peripheral surface may be sealed using resin. In a case where the rotating electrical machine10is used as a power source for a vehicle, the sealing members57are preferably made of a high heat-resistance fluororesin, epoxy resin, PPS resin, PEEK resin, LCP resin, silicone resin, PAI resin, or PI resin. In terms of a linear coefficient expansion to minimize breakage of the sealing members57due to an expansion difference, the sealing members57are preferably made of the same material as that of an outer film of the conductors of the stator winding51. The silicone resin whose linear coefficient expansion is twice or more those of other resins is preferably excluded from the material of the sealing members57. In a case of electrical products, such as electric vehicles equipped with no combustion engine, PPO resin, phenol resin, or FRP resin which resists 180° C. may be used, except in fields where an ambient temperature of the rotating electrical machine is expected to be lower than 100° C. The degree of torque outputted by the rotating electrical machine10is usually proportional to the degree of magnetic flux. In a case where a stator core is equipped with teeth, a maximum amount of magnetic flux in the stator core is restricted depending upon the saturation magnetic flux density in the teeth, while in a case where the stator core is not equipped with teeth, the maximum amount of magnetic flux in the stator core is not restricted. Such a structure is, therefore, useful for increasing an amount of electrical current delivered to the stator winding51to increase the degree of torque produced by the rotating electrical machine10. This embodiment employs the slot-less structure in which the stator50is not equipped with teeth, thereby resulting in a decrease in inductance of the stator50. Specifically, a stator of a typical rotating electrical machine in which conductors are disposed in slots isolated by teeth from each other has an inductance of approximately 1 mH, while the stator50in this embodiment has a decreased inductance of 5 to 60 μH. The rotating electrical machine10in this embodiment is of an outer rotor type, but has a decreased inductance of the stator50to decrease a mechanical time constant Tm. In other words, the rotating electrical machine10is capable of outputting a high degree of torque and designed to have a decreased value of the mechanical time constant Tm. If inertia is defined as J, inductance is defined as L, torque constant is defined as Kt, and back electromotive force constant is defined as Ke, the mechanical time constant Tm is calculated according to the equation of Tm=(J×L)/(Kt×Ke). This shows that a decrease in inductance L will result in a decrease in mechanical time constant Tm. Each of the conductor groups81arranged radially outside the stator core52is made of a plurality of conductors82whose transverse section is of a flattened rectangular shape and which are disposed on one another in the radial direction of the stator core52. Each of the conductors82is oriented to have a transverse section meeting a relation of radial dimension <circumferential dimension. This causes each of the conductor groups81to be thin in the radial direction. A conductive region of the conductor group81also extends inside a region occupied by teeth of a typical stator. This creates a flattened conductive region structure in which a sectional area of each of the conductors82is increased in the circumferential direction, thereby alleviating a risk that the amount of thermal energy may be increased by a decrease in sectional area of a conductor arising from flattening of the conductor. A structure in which a plurality of conductors are arranged in the circumferential direction and connected in parallel to each other is usually subjected to a decrease in sectional area of the conductors by a thickness of a coated layer of the conductors, but however, has beneficial advantages obtained for the same reasons as described above. In the following discussion, each of the conductor groups81or each of the conductors82will also be referred to as a conductive member. The stator50in this embodiment is, as described already, designed to have no slots, thereby enabling the stator winding51to be designed to have a conductive region of an entire circumferential portion of the stator50which is larger in size than a non-conductive region unoccupied by the stator winding51in the stator50. In typical rotating electrical machines for vehicles, a ratio of the conductive region/the non-conductive region is usually one or less. In contrast, this embodiment has the conductor groups81arranged to have the conductive region substantially identical in size with or larger in size than the non-conductive region. If the conductor region, as illustrated inFIG.10, occupied by the conductor82(i.e., the straight section83which will be described later in detail) in the circumferential direction is defined as WA, and a conductor-to-conductor region that is an interval between a respective adjacent two of the conductors82is defined as WB, the conductor region WA is larger in size than the conductor-to-conductor region WB in the circumferential direction. The conductor group81of the stator winding51has a thickness in the radial direction thereof which is smaller than a circumferential width of a portion of the stator winding51which lies in a region of one magnetic pole and serves as one of the phases of the stator winding51. In the structure in which each of the conductor groups81is made up of the two conductors82stacked in the form of two layers lying on each other in the radial direction, and the two conductor groups81are arranged in the circumferential direction within a region of one magnetic pole for each phase, a relation of Tc×2<Wc×2 is met where Tc is the thickness of each of the conductors82in the radial direction, and We is the width of each of the conductors82in the circumferential direction. In another structure in which each of the conductor groups81is made up of the two conductors82, and each of the conductor groups81lies within the region of one magnetic pole for each phase, a relation of Tc×2<Wc is preferably met. In other words, in the stator winding51which is designed to have conductor portions (i.e., the conductor groups81) arranged at a given interval away from each other in the circumferential direction, the thickness of each conductor portion (i.e., the conductor group81) in the radial direction is set smaller than the width of a portion of the stator winding51lying in the region of one magnetic pole for each phase in the circumferential direction. In other words, each of the conductors82is preferably shaped to have the thickness Tc in the radial direction which is smaller than the width Wc in the circumferential direction. The thickness 2Tc of each of the conductor groups81each made of a stack of the two conductors82in the radial direction is preferably smaller than the width Wc of each of the conductor groups81in the circumferential direction. The degree of torque produced by the rotating electrical machine10is substantially inversely proportional to the thickness of the stator core52in the radial direction. The conductor groups81arranged radially outside the stator core52are, as described above, designed to have the thickness decreased in the radial direction. This design is useful in increasing the degree of torque outputted by the rotating electrical machine10. This is because a distance between the magnet unit42of the rotor40and the stator core52(i.e., a distance in which there is no iron) may be decreased to decrease the magnetic resistance. This enables interlinkage magnetic flux in the stator core52produced by the permanent magnets to be increased to enhance the torque. The decrease in thickness of the conductor groups81facilitates the ease with which a magnetic flux leaking from the conductor groups81is collected in the stator core52, thereby preventing the magnetic flux from leaking outside the stator core52without being used for enhancing the torque. This avoids a drop in magnetic force arising from the leakage of the magnetic flux and increases the interlinkage magnetic flux in the stator core52produced by the permanent magnets, thereby enhancing the torque. Each of the conductors82is made of a coated conductor formed by covering the surface of the conductor body82awith the coating82b. The conductors82stacked on one another in the radial direction are, therefore, insulated from each other. Similarly, the conductors82are insulated from the stator core52. The insulating coating82bmay be a coating of each wire86, as will be described later in detail, in a case where each wire86is made of wire with a self-bonded coating or may be made by an additional insulator disposed on a coating of each wire86. Each phase winding made of the conductors82is insulated by the coating82bexcept an exposed portion thereof for joining purposes. The exposed portion includes, for example, an input or an output terminal or a neutral point in a case of a star connection. The conductor groups81arranged adjacent each other in the radial direction are firmly adhered to each other using resin or self-bonding coated wire, thereby minimizing a risk of insulation breakdown, mechanical vibration, or noise caused by rubbing of the conductors82. In this embodiment, the conductor body82ais made of a collection of a plurality of wires86. Specifically, the conductor body82ais, as can be seen inFIG.13, made of a strand of the twisted wires86. Each of the wires86is, as can be seen inFIG.14, made of a bundle of a plurality of thin conductive fibers87. For instance, each of the wires86is made of a complex of CNT (carbon nanotube) fibers. The CNT fibers include boron-containing microfibers in which at least a portion of carbon is substituted with boron. Instead of the CNT fibers that are carbon-based microfibers, vapor grown carbon fiber (VGCF) may be used, but however, the CNT fiber is preferable. The surface of the wire86is covered with a layer of insulating polymer, such as enamel. The surface of the wire86is preferably covered with an enamel coating, such as polyimide coating or amide-imide coating. The conductors82constitute n-phase windings of the stator winding51. The wires86of each of the conductors82(i.e., the conductor body82a) are placed in contact with each other. Each of the conductors82has one of more portions which are formed by twisting the wires86and define one or more portions of a corresponding one of the phase-windings. A resistance value between the twisted wires86is larger than that of each of the wires86. In other words, the respective adjacent two wires86have a first electrical resistivity in a direction in which the wires86are arranged adjacent each other. Each of the wires86has a second electrical resistivity in a lengthwise direction of the wire86. The first electrical resistivity is larger than the second electrical resistivity. Each of the conductors82may be made of an assembly of wires, i.e., the twisted wires86covered with insulating members whose first electrical resistivity is very high. The conductor body82aof each of the conductors82is made of a strand of the twisted wires86. The conductor body82ais, as described above, made of the twisted wires86, thereby reducing an eddy current created in each of the wires86, which reduces an eddy current in the conductor body82a. Each of the wires86is twisted, thereby causing each of the wires86to have portions where directions of applied magnetic field are opposite each other, which cancels a back electromotive force. This results in a reduction in the eddy current. Particularly, each of the wires86is made of the conductive fibers87, thereby enabling the conductive fibers87to be thin and also enabling the number of times the conductive fibers87are twisted to be increased, which enhances the reduction in eddy current. How to insulate the wires86from each other is not limited to the above described use of the polymer insulating layer, but the contact resistance may be used to resist a flow of current between the wires86. In other words, the above beneficial advantage is obtained by a difference in potential arising from a difference between the resistance between the twisted wires86and the resistance of each of the wires86as long as the resistance between the wires86is larger than that of each of the wires86. For instance, the contact resistance may be increased by using production equipment for the wires86and production equipment for the stator50(i.e., an armature) of the rotating electrical machine10as discrete devices to cause the wires86to be oxidized during a transport time or a work interval. Each of the conductors82is, as described above, of a low-profile or flattened rectangular shape in cross section. The more than one conductors82are arranged in the radial direction. Each of the conductors82is made of a strand of the wires86each of which is formed by a self-bonding coating wire equipped with, for example, a fusing or bonding layer or an insulating layer and which are twisted with the bonding layers fused together. Each of the conductors82may alternatively be made by forming twisted wires with no bonding layer or twisted self-bonding coating wires into a desired shape using synthetic resin. The insulating coating82bof each of the conductors82may have a thickness of 80 μm to 100 μm which is larger than that of a coating of typical wire (i.e., 5 μm to 40 μm). In this case, a required degree of insulation between the conductors82is achieved even if no insulating sheet is interposed between the conductors82. It is also advisable that the insulating coating82bbe higher in degree of insulation than the insulating layer of the wire86to achieve insulation between the phase windings. For instance, the polymer insulating layer of the wire86has a thickness of, for example, 5 μm. In this case, the thickness of the insulating coating82bof the conductor82is preferably selected to be 80 μm to 100 μm to achieve the insulation between the phase windings. Each of the conductors82may alternatively be made of a bundle of the untwisted wires86. In brief, each of the conductors82may be made of a bundle of the wires86whose entire lengths are twisted, whose portions are twisted, or whose entire lengths are untwisted. Each of the conductors82constituting the conductor portion is, as described above, made of a bundle of the wires86. The resistance between the wires86is larger than that of each of the wires86. The conductors82are each bent and arranged in a given pattern in the circumferential direction of the stator winding51, thereby forming the phase-windings of the stator winding51. The stator winding51, as illustrated inFIG.12, includes the coil side portion53and the coil ends54and55. The conductors82have the straight sections83which extend straight in the axial direction of the stator winding51and form the coil side portion53. The conductors82have the turns84which are arranged outside the coil side portion53in the axial direction and form the coil ends54and55. Each of the conductor82is made of a wave-shaped string of conductor formed by alternately arranging the straight sections83and the turns84. The straight sections83are arranged to face the magnet unit42in the radial direction. The straight sections83are arranged at a given interval away from each other and joined together using the turns84located outside the magnet unit42in the axial direction. The straight sections83correspond to a magnet facing portion. In this embodiment, the stator winding51is shaped in the form of an annular distributed winding. In the coil side portion53, the straight sections83are arranged at an interval away from each other which corresponds to each pole pair of the magnet unit42for each phase. In each of the coil ends54and55, the straight sections83for each phase are joined together by the turn84which is of a V-shape. The straight sections83which are paired for each pole pair are opposite to each other in a direction of flow of electrical current. A respective two of the straight sections83which are joined together by each of the turns84are different between the coil end54and the coil end55. The joints of the straight sections83by the turns84are arranged in the circumferential direction on each of the coil ends54and55to complete the stator winding in a hollow cylindrical shape. More specifically, the stator winding51is made up of two pairs of the conductors82for each phase. The stator winding51is equipped with a first three-phase winding set including the U-phase winding, the V-phase winding, and the W-phase winding and a second three-phase phase winding set including the X-phase winding, the Y-phase winding, and the Z-phase winding. The first three-phase phase winding set and the second three-phase winding set are arranged adjacent each other in the radial direction in the form of two layers. If the number of phases of the stator winding51is defined as S (i.e.,6in this embodiment), the number of the conductors82for each phase is defined as m, 2×S×m=2Sm conductors82are used for each pole pair in the stator winding51. The rotating electrical machine in this embodiment is designed so that the number of phases S is 6, the number m is 4, and 8 pole pairs are used. 6×4×8=192 conductors82are arranged in the circumferential direction of the stator core52. The stator winding51inFIG.12is designed to have the coil side portion53which has the straight sections82arranged in the form of two overlapping layers disposed adjacent each other in the radial direction. Each of the coil ends54and55has a respective two of the turns84which extend from the radially overlapping straight sections82in opposite circumferential directions. In other words, the conductors82arranged adjacent each other in the radial direction are opposite to each other in direction in which the turns84extend except for ends of the stator winding51. A winding structure of the conductors82of the stator winding51will be described below in detail. In this embodiment, the conductors82formed in the shape of a wave winding are arranged in the form of a plurality of layers (e.g., two layers) disposed adjacent or overlapping each other in the radial direction.FIGS.15(a) and15(b)illustrate the layout of the conductors82which form the nthlayer.FIG.15(a)shows the configurations of the conductor82, as the side of the stator winding51is viewed.FIG.15(b)shows the configurations of the conductors82as viewed in the axial direction of the stator winding51. InFIGS.15(a) and15(b), locations of the conductor groups81are indicated by symbols D1, D2, D3, . . . , and D9. For the sake of simplicity of disclosure,FIGS.15(a) and15(b)show only three conductors82which will be referred to herein as the first conductor82_A, the second conductor82_B, and the third conductor82_C. The conductors82_A to82_C have the straight sections83arranged at a location of the nthlayer, in other words, at the same position in the circumferential direction. Every two of the straight sections82which are arranged at6pitches (corresponding to 3×m pairs) away from each other are joined together by one of the turns84. In other words, in the conductors82_A to82_C, an outermost two of the seven straight sections83arranged in the circumferential direction of the stator winding51on the same circle defined about the center of the rotor40are joined together using one of the turns84. For instance, in the first conductor82_A, the straight sections83placed at the locations D1and D7are joined together by the inverse V-shaped turn84. The conductors82_B and82_C are arranged at an interval equivalent to an interval between a respective adjacent two of the straight sections83away from each other in the circumferential direction at the location of the nthlayer. In this layout, the conductors82_A to82_C are placed at a location of the same layer, thereby resulting in a risk that the turns84thereof may physically interfere with each other. In order to alleviate such a risk, each of the turns84of the conductors82_A to82_C in this embodiment is shaped to have an interference avoiding portion formed by offsetting a portion of the turn84in the radial direction. Specifically, the turn84of each of the conductors82_A to82_C includes the slant portion84a, the head portion84b, the slant portion84c, and the return portion84d. The slant portion84aextends in the circumferential direction of the same circle (which will also be referred to as a first circle). The head portion84extends from the slant portion84aradially inside the first circle (i.e., upward inFIG.15(b)) to reach another circle (which will also be referred to as a second circle). The slant portion84cextends in the circumferential direction of the second circle. The return portion84dreturns from the second circle back to the first circle. The head portion84b, the slant portion84c, and the return portion84ddefine the interference avoiding portion. The slant portion84cmay be arranged radially outside the slant portion84a. In other words, each of the conductors82_A to82_C has the turn84shaped to have the slant portion84aand the slant portion84cwhich are arranged on opposite sides of the head portion84bat the center in the circumferential direction. The locations of the slant portions84aand84bare different from each other in the radial direction (i.e., a direction perpendicular to the drawing ofFIG.15(a)or a vertical direction inFIG.15(b)). For instance, the turn84of the first conductor82_A is shaped to extend from the location D1on the nthlayer in the circumferential direction, be bent at the head portion84bthat is the center of the circumferential length of the turn84in the radial direction (e.g., radially inwardly), be bent again in the circumferential direction, extend again in the circumferential direction, and then be bent at the return portion84din the radial direction (e.g., radially outwardly) to reach the location D7on the nthlayer. With the above arrangements, the slant portions84aof the conductors82_A to82_C are arranged vertically or downward in the order of the first conductor82_A, the second conductor82_B, and the third conductor82_C. The head portions84bchange the order of the locations of the conductors82_A to82_C in the vertical direction, so that the slant portions84care arranged vertically or downward in the order of the third conductor82_3, the second conductor82_B, and the first conductor82_A. This layout achieves an arrangement of the conductors82_A to82_C in the circumferential direction without any physical interference with each other. In the structure wherein the conductors82are laid to overlap each other in the radial direction to form the conductor group81, the turns84leading to a radially innermost one and a radially outermost one of the straight sections83forming the two or more layers are preferably located radially outside the straight sections83. In a case where the conductors83forming the two or more layers are bent in the same radial direction near boundaries between ends of the turns84and the straight sections83, the conductors83are preferably shaped not to deteriorate the insulation therebetween due to physical interference of the conductors83with each other. In the example ofFIGS.15(a) and15(b), the conductors82laid on each other in the radial direction are bent radially at the return portions84dof the turns84at the location D7to D9. It is advisable that the conductor82of the nthlayer and the conductor82of the n+1thlayer be bent, as illustrated inFIG.16, at radii of curvature different from each other. Specifically, the radius of curvature R1of the conductor82of the nthlayer is preferably selected to be smaller than the radius of curvature R2of the conductor82of the n+1thlayer. Additionally, radial displacements of the conductor82of the nthlayer and the conductor82of the n+1thlayer are preferably selected to be different from each other. If the amount of radial displacement of the conductor82of the nthlayer is defined as S1, and the amount of radial displacement of the conductor82of the n+1thlayer located radially outside the nth layer defined as S2, the amount of radial displacement S1is preferably selected to be greater than the amount of radial displacement S2. The above layout of the conductors82eliminates the risk of interference with each other, thereby ensuring a required degree of insulation between the conductors82even when the conductors82laid on each other in the radial direction are bent in the same direction. The structure of the magnet unit42of the rotor40will be described below. In this embodiment, the magnet unit42is made of permanent magnets in which a remanent flux density Br=1.0T, and an intrinsic coercive force Hcj=400 kA/m. The permanent magnets used in this embodiment are implemented by sintered magnets formed by sintering grains of magnetic material and compacting them into a given shape and have the following specifications. The intrinsic coercive force Hcj on a J-H curve is 400 kA/m or more. The remanent flux density Br on the J-H curve is 1.0T or more. Magnets designed so that when 5,000 to 10,000AT is applied thereto by phase-to-phase excitation, a magnetic distance between paired poles, i.e., between a N-pole and an S-pole, in other words, of a path in which a magnetic flux flows between the N-pole and the S-pole, a portion lying in the magnet has a length of 25 mm may be used to meet a relation of Hcj=10000A without becoming demagnetized. In other words, the magnet unit42is engineered so that a saturation magnetic flux density Js is 1.2T or more, a grain size is 10 μm or less, and a relation of Js×a≥1.0T is met where a is an orientation ratio. The magnet unit42will be additionally described below. The magnet unit42(i.e., magnets) has a feature that Js meets a relation of 2.15T≥Js≥1.2T. In other words, magnets used in the magnet unit42may be FeNi magnets having NdFe11TiN, Nd2Fe14B, Sm2Fe17N3, or L10 crystals. Note that samarium-cobalt magnets, such as SmCoS, FePt, Dy2Fe14B, or CoPt magnets can not be used. When magnets in which high Js characteristics of neodymium are slightly lost, but a high degree of coercive force of Dy is ensured using the heavy rare earth dysprosium, like in homotopic compounds, such as Dy2Fe14B and Nd2Fe14B, sometimes meets a relation of 2.15T≥Js≥1.2T, they may be used in the magnet unit42. Such a type of magnet will also be referred to herein as [Nd1−xDyx]2Fe14B]. Further, a magnet contacting different types of compositions, in other words, a magnet made from two or more types of materials, such as FeNi and Sm2Fe17N3, may be used to meet a relation of 2.15T≥Js≥1.2T. A mixed magnet made by adding a small amount of, for example, Dy2Fe14B in which Js<1T to an Nd2Fe14B magnet in which Js=1.6T, meaning that Js is sufficient to enhance the coercive force, may also be used to meet a relation of 2.15T≥Js≥1.2T. In use of the rotating electrical machine at a temperature outside a temperature range of human activities which is higher than, for example, 60° C. exceeding temperatures of deserts, for example, within a passenger compartment of a vehicle where the temperature may rise to 80° C. in summer, the magnet preferably contains FeNi or Sm2Fe17N3 components which are less dependent on temperature. This is because motor characteristics are greatly changed by temperature-dependent factors thereof in motor operations within a range of approximately −40° which is within a range experienced by societies in Northern Europe to 60° C. or more experienced in desert region or at 180 to 240° C. that is a heat resistance temperature of the enamel coating, which leads to a difficulty in achieving a required control operation using the same motor driver. The use of FeNi containing the above described L10 crystals or Sm2Fe17N3 magnets will result in a decrease in load on the motor driver because characteristics thereof have temperature-dependent factors lower than half that of Nd2Fe14B magnets. Additionally, the magnet unit42is engineered to use the above described magnet mixing so that a particle size of fine powder before being magnetically oriented is lower than or equal to 10 μm and higher than or equal to a size of single-domain particles. The coercive force of a magnet is usually increased by decreasing the size of powered particles thereof to a few hundred nm. In recent years, smallest possible particles have been used. If the particles of the magnet are too small, the BHmax (i.e., the maximum energy product) of the magnet will be decreased due to oxidization thereof. It is, thus, preferable that the particle size of the magnet is higher than or equal to the size of the single-domain particles. The particle size being only up to the size of the single-domain particles is known to increase the coercive force of the magnet. The particle size, as referred to herein, refers to the diameter or size of fine powdered particles in a magnetic orientation operation in production processes of magnets. Each of the first magnet91and the second magnet92of the magnet unit42are made of sintered magnets formed by firing or heating magnetic powder at high temperatures and compacting it. The sintering is achieved so as to meet conditions where the saturation magnetization Js of the magnet unit42is 1.2T (Tesla) or more, the particle size of the first magnet91and the second magnet92is 10 μm or less, and Js×a is higher than or equal to 1.0T (Tesla) where a is an orientation ratio. Each of the first magnet91and the second magnet92are also sintered to meet the following conditions. By performing the magnetic orientation in the magnetic orientation operation in the production processes of the first magnet91and the second magnet92, they have an orientation ratio different to the definition of orientation of magnetic force in a magnetization operation for isotropic magnets. The magnet unit42in this embodiment is designed to have the saturation magnetization Js more than or equal to 1.2T and the orientation ratio a of the first magnet91and the second magnet92which is high to meet a relation of Jr≥Js×a≥1.0T. The orientation ratio a, as referred to herein, is defined in the following way. If each of the first magnet91and the second magnet92has six easy axes of magnetization, five of the easy axes of magnetization are oriented in the same direction A10, and a remaining one of the easy axes of magnetization is oriented in the direction B10angled at 90 degrees to the direction A10, then a relation of a=⅚ is met. Alternatively, if each of the first magnet91and the second magnet92has six easy axes of magnetization, five of the easy axes of magnetization are oriented in the same direction A10, and a remaining one of the easy axes of magnetization is oriented in the direction B10angled at 45 degrees to the direction A10, then a relation of a=(5+0.707)/6 is met since a component oriented in the direction A10is expressed by cos 45°=0.707. The first magnet91and the second magnet92in this embodiment are, as described above, each made using sintering techniques, but however, they may be produced in another way as long as the above conditions are satisfied. For instance, a method of forming an MQ3magnet may be used. In this embodiment, permanent magnets are used which are magnetically oriented to control the easy axis of magnetization thereof, thereby enabling a magnetic circuit length within the magnets to be longer than that within typical linearly oriented magnets which produces a magnetic flux density of 1.0T or more. In other words, the magnetic circuit length for one pole pair in the magnets in this embodiment may be achieved using magnets with a small volume. Additionally, a range of reversible flux loss in the magnets is not lost when subjected to severe high temperatures, as compared with use of typical linearly oriented magnets. The inventors of this application have found that characteristics similar to those of anisotropic magnets are obtained even using prior art magnets. The easy axis of magnetization represents a crystal orientation in which a crystal is easy to magnetize in a magnet. The orientation of the easy axis of magnetization in the magnet, as referred to herein, is a direction in which an orientation ratio is 50% or more where the orientation ratio indicates the degree to which easy axes of magnetization of crystals are aligned with each other or a direction of an average of magnetic orientations in the magnet. The magnet unit42is, as clearly illustrated inFIGS.8and9, of an annular shape and arranged inside the magnet holder41(specifically, radially inside the cylinder43). The magnet unit42is equipped with the first magnets91and the second magnets92which are each made of a polar anisotropic magnet. Each of the first magnets91and each of the second magnets92are different in polarity from each other. The first magnets91and the second magnets92are arranged alternately in the circumferential direction of the magnet unit42. Each of the first magnets91is engineered to have a portion creating an N-pole near the stator winding51. Each of the second magnets92is engineered to have a portion creating an S-pole near the stator winding51. The first magnets91and the second magnets92are each made of, for example, a permanent rare earth magnet, such as a neodymium magnet. Each of the magnets91and92is engineered to have a direction of magnetization (which will also be referred to below as a magnetization direction) which extends in an annular shape in between a d-axis (i.e., a direct-axis) and a q-axis (i.e., a quadrature-axis) in a known d-q coordinate system where the d-axis represents the center of a magnetic pole, and the q-axis represents a magnetic boundary between the N-pole and the S-pole, in other words, where a density of magnetic flux is zero Tesla. In each of the magnets91and92, the magnetization direction is oriented in the radial direction of the annular magnet unit42close to the d-axis and also oriented in the circumferential direction of the annular magnet unit42closer to the q-axis. This layout will also be described below in detail. Each of the magnets91and92, as can be seen inFIG.9, includes a first portion250and two second portions260arranged on opposite sides of the first portion250in the circumferential direction of the magnet unit42. In other words, the first portion250is located closer to the d-axis than the second portions260are. The second portions260are arranged closer to the q-axis than the first portion250is. The direction in which the easy axis of magnetization300extends in the first portion250is oriented more parallel to the d-axis than the direction in which the easy axis of magnetization310extends in the second portions260. In other words, the magnet unit42is engineered so that an angle θ11which the easy axis of magnetization300in the first portion250makes with the d-axis is selected to be smaller than an angle θ12which the easy axis of magnetization310in the second portion260makes with the q-axis. More specifically, if a direction from the stator50(i.e., an armature) toward the magnet unit42on the d-axis is defined to be positive, the angle θ11represents an angle which the easy axis of magnetization300makes with the d-axis. Similarly, if a direction from the stator50(i.e., an armature) toward the magnet unit42on the q-axis is defined to be positive, the angle θ12represents an angle which the easy axis of magnetization310makes with the q-axis. In this embodiment, each of the angle θ11and the angle θ12is set to be 90° or less. Each of the easy axes of magnetization300and310, as referred to herein, is defined in the following way. If in each of the magnets91and92, a first one of the easy axes of magnetization is oriented in a direction A11, and a second one of the easy axes of magnetization is oriented in a direction B11, an absolute value of cosine of an angle θ which the direction A11and the direction B11make with each other (i.e., |cos θ|) is defined as the easy axis of magnetization300or the easy axis of magnetization310. The magnets91are different in easy axis of magnetization from the magnets92in regions close to the d-axis and the q-axis. Specifically, in the region close to the d-axis, the direction of the easy axis of magnetization is oriented approximately parallel to the d-axis, while in the region close to the q-axis, the direction of the easy axis of magnetization is oriented approximately perpendicular to the q-axis. Annular magnetic paths are created according to the directions of easy axes of magnetization. In each of the magnets91and92, the easy axis of magnetization in the region close to the d-axis may be oriented parallel to the d-axis, while the easy axis of magnetization in the region close to the q-axis may be oriented perpendicular to the q-axis. Each of the magnets91and92is shaped to have a stator-side outer peripheral surface facing the stator50(i.e., a lower surface viewed inFIG.9) and a q-axis-side outer peripheral surface facing the q-axis in the circumferential direction. The stator-side outer peripheral surface and the q-axis-side outer peripheral surface function as magnetic flux input and output surfaces that are magnetic flux acting surfaces into and from which magnetic flux flows, respectively. The magnetic paths are each created to extend between the magnetic flux acting surfaces (i.e., between the stator-side outer peripheral surface and the q-axis-side outer peripheral surface). In the magnet unit42, a magnetic flux flows in an annular shape between a respective adjacent two of the N-poles and the S-poles of the magnets91and92, so that each of the magnetic paths has an increased length, as compared with, for example, radial anisotropic magnets. A distribution of the magnetic flux density will, therefore, exhibit a shape similar to a sine wave illustrated inFIG.17. This facilitates concentration of magnetic flux around the center of the magnetic pole unlike a distribution of magnetic flux density of a radial anisotropic magnet demonstrated inFIG.18as a comparative example, thereby enabling the degree of torque produced by the rotating electrical machine10to be increased. It has also been found that the magnet unit42in this embodiment has the distribution of the magnetic flux density distinct from that of a typical Halbach array magnet. InFIGS.17and18, a horizontal axis indicates the electrical angle, while a vertical axis indicates the magnetic flux density. 90° on the horizontal axis represents the d-axis (i.e., the center of the magnetic pole). 0° and 180° on the horizontal axis represent the q-axis. Accordingly, the above described structure of each of the magnets91and92functions to enhance the magnet magnetic flux thereof on the d-axis and reduce a change in magnetic flux near the q-axis. This enables the magnets91and92to be produced which have a smooth change in surface magnetic flux from the q-axis to the d-axis on each magnetic pole The sine wave matching percentage in the distribution of the magnetic flux density is preferably set to, for example, 40% or more. This improves the amount of magnetic flux around the center of a waveform of the distribution of the magnetic flux density as compared with a radially oriented magnet or a parallel oriented magnet in which the sine wave matching percentage is approximately 30%. By setting the sine wave matching percentage to be 60% or more, the amount of magnetic flux around the center of the waveform is improved, as compared with a concentrated magnetic flux array, such as the Halbach array. In the radial anisotropic magnet demonstrated inFIG.18, the magnetic flux density changes sharply near the q-axis. The more sharp the change in magnetic flux density, the more an eddy current generating in the stator winding51will increase. The magnetic flux close to the stator winding51also sharply changes. In contrast, the distribution of the magnetic flux density in this embodiment has a waveform approximating a sine wave. A change in magnetic flux density near the q-axis is, therefore, smaller than that in the radial anisotropic magnet near the q-axis. This minimizes the generation of the eddy current. The magnet unit42creates a magnetic flux oriented perpendicular to the magnetic flux acting surface280close to the stator50near the d-axis (i.e., the center of the magnetic pole) in each of the magnets91and92. Such a magnetic flux extends in an arc-shape farther away from the d-axis as leaving the magnetic flux acting surface280close to the stator50. The more perpendicular to the magnetic flux acting surface the magnetic flux extends, the stronger the magnetic flux is. The rotating electrical machine10in this embodiment is, as described above, designed to shape each of the conductor groups81to have a decreased thickness in the radial direction, so that the radial center of each of the conductor groups81is located close to the magnetic flux-acting surface of the magnet unit42, thereby causing the strong magnetic flux to be applied to the stator50from the rotor40. The stator50has the cylindrical stator core52arranged radially inside the stator winding51, that is, on the opposite side of the stator winding51to the rotor40. This causes the magnetic flux extending from the magnetic flux-acting surface of each of the magnets91and92to be attracted by the stator core52, so that it circulates through the magnetic path partially including the stator core52. This enables the orientation of the magnetic flux and the magnetic path to be optimized. Steps to assemble the bearing unit20, the housing30, the rotor40, the stator50, and the inverter unit60illustrated inFIG.5will be described below as a production method of the rotating electrical machine10. The inverter unit60is, as illustrated inFIG.6, equipped with the unit base61and the electrical components62. Operation processes including installation processes for the unit base61and the electrical components62will be explained. In the following discussion, an assembly of the stator50and the inverter unit60will be referred to as a first unit. An assembly of the bearing unit20, the housing30, and the rotor40will be referred to as a second unit. The production processes include: a first step of installing the electrical components62radially inside the unit base61; a second step of installing the unit base61radially inside the stator50to make the first unit; a third step of inserting the attaching portion44of the rotor40into the bearing unit20installed in the housing30to make the second unit; a fourth step of installing the first unit radially inside the second unit; and a fifth step of fastening the housing30and the unit base61together. The order in which the above steps are performed is the first step→the second step→the third step→the fourth step→the fifth step. In the above production method, the bearing unit20, the housing30, the rotor40, the stator50, and the inverter unit60are assembled as a plurality of sub-assemblies, and the sub-assemblies are assembled, thereby facilitating handling thereof and achieving completion of inspection of each sub-assembly. This enables an efficient assembly line to be established and thus facilitates multi-product production planning. In the first step, a high thermal conductivity material is applied or adhered to at least one of the radial inside of the unit base61and the radial outside of the electrical components62. Subsequently, the electrical components may be mounted on the unit base61. This achieves efficient transfer of heat, as generated by the semiconductor modules66, to the unit base61. In the third step, an insertion operation for the rotor40may be achieved with the housing30and the rotor40arranged coaxially with each other. Specifically, the housing30and the rotor40are assembled while sliding one of the housing30and the rotor40along a jig which positions the outer peripheral surface of the rotor40(i.e., the outer peripheral surface of the magnetic holder41) or the inner peripheral surface of the rotor40(i.e., the inner peripheral surface of the magnet unit42) with respect to, for example, the inner peripheral surface of the housing30. This achieves the assembly of heavy-weight parts without exertion of imbalanced load to the bearing unit20. This results in improvement of reliability in operation of the bearing unit20. In the fourth step, the first unit and the second unit may be installed while being placed coaxially with each other. Specifically, the first unit and the second unit are installed while sliding one of the first unit and the second unit along a jig which positions the inner peripheral surface of the unit base61with respect to, for example, the inner peripheral surfaces of the rotor40and the attaching portion44. This achieves the installation of the first and second units without any physical interference therebetween within a small clearance between the rotor40and the stator50, thereby eliminating risks of defects caused by the installation, such as physical damage to the stator winding51or damage to the permanent magnets. The above steps may alternatively be scheduled as the second step→the third step→the fourth step→the fifth step→the first step. In this order, the delicate electrical components62are finally installed, thereby minimizing stress on the electrical components in the installation processes. The structure of a control system for controlling an operation of the rotating electrical machine10will be described below.FIG.19is an electrical circuit diagram of the control system for the rotating electrical machine10.FIG.20is a functional block diagram which illustrates control steps performed by the controller110. FIG.19illustrates two sets of three-phase windings51aand51b. The three-phase winding51aincludes a U-phase winding, a V-phase winding, and a W-phase winding. The three-phase winding51bincludes an X-phase winding, a Y-phase winding, and a Z-phase winding. The first inverter101and the second inverter102are provided as electrical power converters for the three-phase windings51aand51b, respectively. The inverters101and102are made of bridge circuits with as many upper and lower arms as there are the phase-windings. The current delivered to the phase windings of the stator winding51is regulated by turning on or off switches (i.e., semiconductor switches) mounted on the upper and lower arms. The dc power supply103and the smoothing capacitor104are connected parallel to the inverters101and102. The dc power supply103is made of, for example, a plurality of series-connected cells. The switches of the inverters101and102correspond to the semiconductor modules66inFIG.1. The capacitor104corresponds to the capacitor module68inFIG.1. The controller110is equipped with a microcomputer made of a CPU and memories and works to perform control energization by turning on or off the switches of the inverters101and102using several types of measured information measured in the rotating electrical machine10or requests for a motor mode or a generator mode of the rotating electrical machine10. The controller110corresponds to the control device77shown inFIG.6. The measured information about the rotating electrical machine10includes, for example, an angular position (i.e., an electrical angle) of the rotor40measured by an angular position sensor, such as a resolver, a power supply voltage (i.e., voltage inputted into the inverters) measured by a voltage sensor, and electrical current delivered to each of the phase-windings, as measured by a current sensor. The controller110produces and outputs an operation signal to operate each of the switches of the inverters101and102. A request for electrical power generation is a request for driving the rotating electrical machine10in a regenerative mode, for example, in a case where the rotating electrical machine10is used as a power source for a vehicle. The first inverter101is equipped with a series-connected part made up of an upper arm switch Sp and a lower arm switch Sn for each of the three-phase windings: the U-phase winding, the V-phase winding, and the W-phase winding. The upper arm switches Sp are connected at high-potential terminals thereof to a positive terminal of the dc power supply103. The lower arm switches Sn are connected at low-potential terminals thereof to a negative terminal (i.e., ground) of the dc power supply103. Intermediate joints of the upper arm switches Sp and the lower arm switches Sn are connected to ends of the U-phase winding, the V-phase winding, and the W-phase winding. The U-phase winding, the V-phase winding, and the W-phase winding are connected in the form of a star connection (i.e., Y-connection). The other ends of the U-phase winding, the V-phase winding, and the W-phase winding are connected with each other at a neutral point. The second inverter102is, like the first inverter101, equipped with a series-connected part made up of an upper arm switch Sp and a lower arm switch Sn for each of the three-phase windings: the X-phase winding, the Y-phase winding, and the Z-phase winding. The upper arm switches Sp are connected at high-potential terminals thereof to the positive terminal of the dc power supply103. The lower arm switches Sn are connected at low-potential terminals thereof to the negative terminal (i.e., ground) of the dc power supply103. Intermediate joints of the upper arm switches Sp and the lower arm switches Sn are connected to ends of the X-phase winding, the Y-phase winding, and the Z-phase winding. The X-phase winding, the Y-phase winding, and the Z-phase winding are connected in the form of a star connection (i.e., Y-connection). The other ends of the X-phase winding, the Y-phase winding, and the Z-phase winding are connected with each other at a neutral point. FIG.20illustrates a current feedback control operation to control electrical currents delivered to the U-phase winding, the V-phase winding, and the W-phase winding and a current feedback control operation to control electrical currents delivered to the X-phase winding, the Y-phase winding, and the Z-phase winding. The control operation for the U-phase winding, the V-phase winding, and the W-phase winding will first be discussed. InFIG.20, the current command determiner111uses a torque-dq map to determine current command values for the d-axis and the q-axis using a torque command value in the motor mode of the rotating electrical machine10(which will also be referred to as a motor-mode torque command value), a torque command value in the generator mode of the rotating electrical machine10(which will be referred to as a generator-mode torque command value), and an electrical angular velocity ω derived by differentiating an electrical angle θ with respect to time. The current command determiner111is shared between the U-, V-, and W-phase windings and the X-, Y-, and W-phase windings. The generator-mode torque command value is a regenerative torque command value in a case where the rotating electrical machine10is used as a power source of a vehicle. The d-q converter112works to convert currents (i.e., three phase currents), as measured by current sensors mounted for the respective phase windings, into a d-axis current and a q-axis current that are components in a two-dimensional rotating Cartesian coordinate system in which a d-axis is defined as a direction of an axis of a magnetic field or field direction. The d-axis current feedback control device113determines a command voltage for the d-axis as a manipulated variable for bringing the d-axis current into agreement with the current command value for the d-axis in a feedback mode. The q-axis current feedback control device114determines a command voltage for the q-axis as a manipulated variable for bringing the q-axis current into agreement with the current command value for the q-axis in a feedback mode. The feedback control devices113and114calculates the command voltage as a function of a deviation of each of the d-axis current and the q-axis current from a corresponding one of the current command values using PI feedback techniques. The three-phase converter115works to convert the command values for the d-axis and the q-axis into command values for the U-phase, V-phase, and W-phase windings. Each of the devices111to115is engineered as a feedback controller to perform a feedback control operation for a fundamental current in the d-q transformation theory. The command voltages for the U-phase, V-phase, and W-phase windings are feedback control values. The operation signal generator116uses the known triangle wave carrier comparison to produce operation signals for the first inverter101as a function of the three-phase command voltages. Specifically, the operation signal generator116works to produce switch operation signals (i.e., duty signals) for the upper and lower arms for the three-phase windings (i.e., the U-, V-, and W-phase windings) under PWM control based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The same structure as described above is provided for the X-, Y-, and Z-phase windings. The d-q converter122works to convert currents (i.e., three phase currents), as measured by current sensors mounted for the respective phase windings, into a d-axis current and a q-axis current that are components in the two-dimensional rotating Cartesian coordinate system in which the d-axis is defined as the direction of the axis of the magnetic field. The d-axis current feedback control device123determines a command voltage for the d-axis. The q-axis current feedback control device124determines a command voltage for the q-axis. The three-phase converter125works to convert the command values for the d-axis and the q-axis into command values for the X-phase, Y-phase, and Z-phase windings. The operation signal generator126produces operation signals for the second inverter102as a function of the three-phase command voltages. Specifically, the operation signal generator126works to switch operation signals (i.e., duty signals) for the upper and lower arms for the three-phase windings (i.e., the X-, Y-, and Z-phase windings) based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The driver117works to turn on or off the switches Sp and Sn in the inverters101and102in response to the switch operation signals produced by the operation signal generators116and126. Subsequently, a torque feedback control operation will be described below. This operation is to increase an output of the rotating electrical machine10and reduce torque loss in the rotating electrical machine10, for example, in a high-speed and high-output range wherein output voltages from the inverters101and102rise. The controller110selects one of the torque feedback control operation and the current feedback control operation and perform the selected one as a function of an operating condition of the rotating electrical machine10. FIG.21shows the torque feedback control operation for the U-, V-, and W-phase windings and the torque feedback control operation for the X-, Y-, and Z-phase windings. InFIG.21, the same reference numbers as employed inFIG.20refer to the same parts, and explanation thereof in detail will be omitted here. The control operation for the U-, V-, and W-phase windings will be described first. The voltage amplitude calculator127works to calculate a voltage amplitude command that is a command value of a degree of a voltage vector as a function of the motor-mode torque command value or the generator-mode torque command value for the rotating electrical machine10and the electrical angular velocity ω derived by differentiating the electrical angle θ with respect to time. The torque calculator128aworks to estimate a torque value in the U-phase, V-phase, or the W-phase as a function of the d-axis current and the q-axis current converted by the d-q converter112. The torque calculator128amay be designed to calculate the voltage amplitude command using a map listing relations among the d-axis current, the q-axis current, and the voltage amplitude command. The torque feedback controller129acalculates a voltage phase command that is a command value for a phase of the voltage vector as a manipulated variable for bringing the estimated torque value into agreement with the motor-mode torque command value or the generator-mode torque command value in the feedback mode. Specifically, the torque feedback controller129acalculates the voltage phase command as a function of a deviation of the estimated torque value from the motor-mode torque command value or the generator-mode torque command value using PI feedback techniques. The operation signal generator130aworks to produce the operation signal for the first inverter101using the voltage amplitude command, the voltage phase command, and the electrical angle θ. Specifically, the operation signal generator130acalculates the command values for the three-phase windings based on the voltage amplitude command, the voltage phase command, and the electrical angle θ and then generates switching operation signals for the upper and lower arms for the three-phase windings by means of PWM control based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The operation signal generator130amay alternatively be designed to produce the switching operation signals using pulse pattern information that is map information about relations among the voltage amplitude command, the voltage phase command, the electrical angle θ, and the switching operation signal, the voltage amplitude command, the voltage phase command, and the electrical angle θ. The same structure as described above is provided for the X-, Y-, and Z-phase windings. The torque calculator128bworks to estimate a torque value in the X-phase, Y-phase, or the Z-phase as a function of the d-axis current and the q-axis current converted by the d-q converter122. The torque feedback controller129bcalculates a voltage phase command as a manipulated variable for bringing the estimated torque value into agreement with the motor-mode torque command value or the generator-mode torque command value in the feedback mode. Specifically, the torque feedback controller129bcalculates the voltage phase command as a function of a deviation of the estimated torque value from the motor-mode torque command value or the generator-mode torque command value using PI feedback techniques. The operation signal generator130bworks to produce the operation signal for the second inverter102using the voltage amplitude command, the voltage phase command, and the electrical angle θ. Specifically, the operation signal generator130bcalculates the command values for the three-phase windings based on the voltage amplitude command, the voltage phase command, and the electrical angle θ and then generates the switching operation signals for the upper and lower arms for the three-phase windings by means of PWM control based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The driver117then works to turn on or off the switches Sp and Sn for the three-phase windings in the inverters101and102in response to the switching operation signals derived by the operation signal generators130aand130b. The operation signal generator130bmay alternatively be designed to produce the switching operation signals using pulse pattern information that is map information about relations among the voltage amplitude command, the voltage phase command, the electrical angle θ, and the switching operation signal, the voltage amplitude command, the voltage phase command, and the electrical angle θ. The rotating electrical machine10has a risk that generation of an axial current may result in electrical erosion in the bearing21or22. For example, when the stator winding51is excited or de-excited in response to the switching operation, a small switching time gap (i.e., switching unbalance) may occur, thereby resulting in distortion of magnetic flux, which leads to the electrical erosion in the bearings21and22retaining the rotating shaft11. The distortion of magnetic flux depends upon the inductance of the stator50and creates an electromotive force oriented in the axial direction, which results in dielectric breakdown in the bearing21or22to develop the electrical erosion. In order to avoid the electrical erosion, this embodiment is engineered to take three measures as discussed below. The first erosion avoiding measure is to reduce the inductance by designing the stator50to have a core-less structure and also to shape the magnetic flux in the magnet unit42to be smooth to minimize the electrical erosion. The second erosion avoiding measure is to retain the rotating shaft in a cantilever form to minimize the electrical erosion. The third erosion avoiding measure is to unify the annular stator winding51and the stator core52using molding techniques using a moulding material to minimize the electrical erosion. The first to third erosion avoiding measures will be described below in detail. In the first erosion avoiding measure, the stator50is designed to have no teeth in gaps between the conductor groups81in the circumferential direction. The sealing members57made of non-magnetic material are arranged in the gaps between the conductor groups81instead of teeth (iron cores) (seeFIG.10). This results in a decrease in inductance of the stator50, thereby minimizing the distortion of magnetic flux caused by the switching time gap occurring upon excitation of the stator winding51to reduce the electrical erosion in the bearings21and22. The inductance on the d-axis is preferably less than that on the q-axis. Additionally, each of the magnets91and92is magnetically oriented to have the easy axis of magnetization which is directed in a region close to the d-axis to be more parallel to the d-axis than that in a region close to the q-axis (seeFIG.9). This strengthens the magnetic flux on the d-axis, thereby resulting in a smooth change in surface magnetic flux (i.e., an increase or decrease in magnetic flux) from the q-axis to the d-axis on each magnetic pole of the magnets91and92. This minimizes a sudden voltage change arising from the switching imbalance to avoid the electrical erosion. In the second erosion avoiding measure, the rotating electrical machine10is designed to have the bearings21and22located away from the axial center of the rotor40toward one of the ends of the rotor40opposed to each other in the axial direction thereof (seeFIG.2). This minimizes the risk of the electrical erosion as compared with a case where a plurality of bearings are arranged outside axial ends of a rotor. In other words, in the structure wherein the rotor has ends retained by the bearings, generation of a high-frequency magnetic flux results in creation of a closed circuit extending through the rotor, the stator, and the bearings (which are arranged axially outside the rotor). This leads to a risk that the axial current may result in the electrical erosion in the bearings. In contrast, the rotor40are retained by the plurality of bearings21and22in the cantilever form, so that the above closed circuit does not occur, thereby minimizing the electrical erosion in the bearings21and22. In addition to the above one-side layout of the bearings21and22, the rotating electrical machine10also has the following structure. In the magnet holder41, the intermediate portion45extending in the radial direction of the rotor40is equipped with the contact avoider which axially extends to avoid physical contact with the stator50(seeFIG.2). This enables a closed circuit through which the axial current flows through the magnet holder41to be lengthened to increase the resistance thereof. This minimizes the risk of the electrical erosion of the bearings21and22. The retainer23for the bearing unit20is secured to the housing30and located on one axial end side of the rotor40, while the housing30and the unit base61(i.e., a stator holder) are joined together on the other axial end of the rotor40(seeFIG.2). These arrangements properly achieve the structure in which the bearings21and22are located only on the one end of the length of the rotating shaft11. Additionally, the unit base61is connected to the rotating shaft11through the housing30, so that the unit base61is located electrically away from the rotating shaft11. An insulating member such as resin may be disposed between the unit base61and the housing30to place the unit base61and the rotating shaft11electrically farther away from each other. This also minimizes the risk of the electrical erosion of the bearings21and22. The one-side layout of the bearings21and22in the rotating electrical machine10in this embodiment decreases the axial voltage applied to the bearings21and22and also decreases the potential difference between the rotor40and the stator50. A decrease in the potential difference applied to the bearings21and22is, thus, achieved without use of conductive grease in the bearings21and22. The conductive grease usually contains fine particles such as carbon particles, thus leading to a risk of generation of acoustic noise. In order to alleviate the above problem, this embodiment uses a non-conductive grease in the bearings21and22to minimize the acoustic noise in the bearings21and22. For instance, in a case where the rotating electrical machine10is used with an electrical vehicle, it is usually required to take a measure to eliminate the acoustic noise. This embodiment is capable of properly taking such a measure. In the third erosion avoiding measure, the stator winding51and the stator core52are unified together using a molding material to minimize a positional error of the stator winding51in the stator50(seeFIG.11). The rotating electrical machine10in this embodiment is designed not to have conductor-to-conductor members (e.g., teeth) between the conductor groups81arranged in the circumferential direction of the stator winding51, thus leading to a concern about the positional error or misalignment of the stator winding51. The misalignment of the conductor of the stator winding51may be minimized by unifying the stator winding51and the stator core52in the mold. This eliminates risks of the distortion of magnetic flux arising from the misalignment of the stator winding51and the electrical erosion in the bearings21and22resulting from the distortion of the magnetic flux. The unit base61serving as a housing to firmly fix the stator core52is made of carbon fiber reinforced plastic (CFRP), thereby minimizing electrical discharge to the unit base61as compared with when the unit base61is made of aluminum, thereby avoiding the electrical erosion. An additional erosion avoiding measure may be taken to make at least one of the outer race25and the inner race26of each of the bearings21and22using a ceramic material or alternatively to install an insulating sleeve outside the outer race25. Other embodiments will be described below in terms of differences between themselves and the first embodiment. Second Embodiment In this embodiment, the polar anisotropy structure of the magnet unit42of the rotor40is changed and will be described below in detail. The magnet unit42is, as clearly illustrated inFIGS.22and23, made using a magnet array referred to as a Halbach array. Specifically, the magnet unit42is equipped with the first magnets131and the second magnets132. The first magnets131have a magnetization direction (i.e., an orientation of a magnetization vector thereof) oriented in the radial direction of the magnet unit42. The second magnets132have a magnetization direction (i.e., an orientation of the magnetization vector thereof) oriented in the circumferential direction of the magnet unit42. The first magnets131are arrayed at a given interval away from each other in the circumferential direction. Each of the second magnets132is disposed between the first magnets131arranged adjacent each other in the circumferential direction. The first magnets131and the second magnets132are each implemented by a rare-earth permanent magnet, such as a neodymium magnet. The first magnets131are arranged away from each other in the circumferential direction so as to have N-poles and S-poles which are created in radially inner portions thereof and face the stator50. The N-poles and the S-poles are arranged alternately in the circumferential direction. The second magnets132are arranged to have N-poles and S-poles alternately located adjacent the first magnets131in the circumferential direction. The cylinder43which surrounds the magnets131and132may be formed as a soft magnetic core made of a soft magnetic material and which functions as a back core. The magnet unit42in this embodiment are designed to have the easy axis of magnetization oriented in the same way as in the first embodiment relative to the d-axis and the q-axis in the d-q axis coordinate system. The magnetic members133each of which is made of a soft magnetic material are disposed radially outside the first magnets131, in other words, close to the cylinder43of the magnet holder41. Each of the magnetic members133may be made of magnetic steel sheet, soft iron, or a dust core material. Each of the magnetic members133has a length identical with that of the first magnet131(especially, a length of an outer periphery of the first magnet131) in the circumferential direction. An assembly made up of each of the first magnets131and a corresponding one of the magnetic members133has a thickness identical with that of the second magnet132in the radial direction. In other words, each of the first magnets131has the thickness smaller than that of the second magnet132by that of the magnetic member133in the radial direction. The magnets131and132and the magnetic members133are firmly secured to each other using, for example, adhesive agent. In the magnet unit42, the radial outside of the first magnets131faces away from the stator50. The magnetic members133are located on the opposite side of the first magnets131to the stator50in the radial direction (i.e., farther away from the stator50). Each of the magnetic members133has the key134in a convex shape which is formed on the outer periphery thereof and protrudes radially outside the magnetic member133, in other words, protrudes into the cylinder43of the magnet holder41. The cylinder43has the key grooves135which are formed in an inner peripheral surface thereof in a concave shape and in which the keys134of the magnetic members133are fit. The protruding shape of the keys134is contoured to conform with the recessed shape of the key grooves135. As many of the key grooves135as the keys134of the magnetic members133are formed. The engagement between the keys134and the key grooves135serves to eliminate misalignment or a positional deviation of the first magnets131, the second magnets132, and the magnet holder41in the circumferential direction (i.e. a rotational direction). The keys134and the key grooves135(i.e., convexities and concavities) may be formed either on the cylinders43of the magnet holder41or in the magnetic members133, respectively. Specifically, the magnetic members133may have the key grooves135in the outer periphery thereof, while the cylinder43of the magnet holder41may have the keys134formed on the inner periphery thereof. The magnet unit42has the first magnets131and the second magnets132alternately arranged to increase the magnetic flux density in the first magnets131. This results in concentration of magnetic flux on one surface of the magnet unit42to enhance the magnetic flux close to the stator50. The layout of the magnetic members133radially arranged outside the first magnets131, in other words, farther away from the stator50reduces partial magnetic saturation occurring radially outside the first magnets131, thereby alleviating a risk of demagnetization in the first magnets131arising from the magnetic saturation. This results in an increase in magnetic force produced by the magnet unit42. In other words, the magnet unit42in this embodiment is viewed to have portions which are usually subjected to the demagnetization and replaced with the magnetic members133. FIGS.24(a) and24(b)are illustrations which demonstrate flows of magnetic flux in the magnet unit42.FIG.24(a)illustrates a conventional structure in which the magnet unit42is not equipped with the magnetic members133.FIG.24(b)illustrates the structure in this embodiment in which the magnet unit42is equipped with the magnetic members133.FIGS.24(a) and24(b)are linearly developed views of the cylinder43of the magnet holder41and the magnet unit42. Lower sides ofFIGS.24(a) and24(b)are close to the stator50, while upper sides thereof are farther away from the stator50. In the structure shown inFIG.24(a), a magnetic flux-acting surface of each of the first magnets131and a side surface of each of the second magnets132are placed in contact with the inner peripheral surface of the cylinder43. A magnetic flux-acting surface of each of the second magnets132is placed in contact with the side surface of one of the first magnets131. Such layout causes a combined magnetic flux to be created in the cylinder43. The combined magnetic flux is made up of a magnetic flux F1which passes outside the second magnet132and then enters the surface of the first magnets131contacting the cylinder43and a magnetic flux which flows substantially parallel to the cylinder43and attracts a magnetic flux F2produced by the second magnet132. This leads to a risk that the magnetic saturation may occur near the surface of contact between the first magnet131and the second magnet132in the cylinder43 In the structure inFIG.24(b)wherein each of the magnetic members133is disposed between the magnetic flux-acting surface of the first magnet131and the inner periphery of the cylinder43farther away from the stator50, the magnetic flux is permitted to pass through the magnetic member133. This minimizes the magnetic saturation in the cylinder43and increases resistance against the demagnetization. The structure inFIG.24(b), unlikeFIG.24(a), functions to eliminate the magnetic flux F2facilitating the magnetic saturation. This effectively enhances the permeance in the whole of the magnetic circuit, thereby ensuring the stability in properties of the magnetic circuit under elevated temperature. As compared with radial magnets used in conventional SPM rotors, the structure inFIG.24(b)has an increased length of the magnetic path passing through the magnet. This results in a rise in permeance of the magnet which enhances the magnetic force to increase the torque. Further, the magnetic flux concentrates on the center of the d-axis, thereby increasing the sine wave matching percentage. Particularly, the increase in torque may be achieved effectively by shaping the waveform of the current to a sine or trapezoidal wave under PWM control or using 120° excitation switching ICs In a case where the stator core52is made of magnetic steel sheets, the thickness of the stator core52in the radial direction thereof is preferably half or greater than half the thickness of the magnet unit42in the radial direction. For instance, it is preferable that the thickness of the stator core52in the radial direction is greater than half the thickness of the first magnets131arranged at the pole-to-pole center in the magnet unit42. It is also preferable that the thickness of the stator core52in the radial direction is smaller than that of the magnet unit42. In this case, a magnet magnetic flux is approximately 1T, while the saturation magnetic flux density in the stator core52is 2T. The leakage of magnetic flux to inside the inner periphery of the stator core52is avoided by selecting the thickness of the stator core52in the radial direction to be greater than half that of the magnet unit42. Magnets arranged to have the Halbach structure or the polar anisotropic structure usually have an arc-shaped magnetic path, so that the magnetic flux may be increased in proportion to a thickness of ones of the magnets which handle a magnetic flux in the circumferential direction. In such a structure, the magnetic flux flowing through the stator core52is thought of as not exceeding the magnetic flux flowing in the circumferential direction. In other words, when the magnetic flux produced by the magnets is 1T, while ferrous metal whose saturation magnetic flux density is 2T is used to make the stator core52, a light weight and compact electrical rotating machine may be produced by selecting the thickness of the stator core52to be greater than half that of the magnets. The demagnetizing field is usually exerted by the stator50on the magnetic field produced by the magnets, so that the magnetic flux produced by the magnets will be 0.9T or less. The magnetic permeability of the stator core may, therefore, be properly kept by selecting the thickness of the stator core to be half that of the magnets. Modifications of the above structure will be described below. First Modification In the above embodiment, the outer peripheral surface of the stator core52has a curved surface without any irregularities. The plurality of conductor groups81are arranged at a given interval away from each other on the outer peripheral surface of the stator core52. This layout may be changed. For instance, the stator core52illustrated inFIG.25is equipped with the circular ring-shaped yoke141and the protrusions142. The yoke141is located on the opposite side (i.e., a lower side, as viewed in the drawing) of the stator winding51to the rotor40in the radial direction. Each of the protrusions142protrudes into a gap between a respective two of the straight sections83arranged adjacent each other in the circumferential direction. The protrusions142are arranged at a given interval away from each other in the circumferential direction radially outside the yoke141, i.e., close to the rotor40. Each of the conductor groups81of the stator winding51engages the protrusions142in the circumferential direction, in other words, the protrusions142are used as positioners to position and array the conductor groups81in the circumferential direction. The protrusions142correspond to conductor-to-conductor members. A radial thickness of each of the protrusions142from the yoke141, in other words, a distance W, as illustrated inFIG.25, between the inner surface320of the straight sections82which is placed in contact with the yoke141and the top of the protrusion412in the radial direction of the yoke141is selected to be smaller than half a radial thickness (as indicated by H1in the drawing) of the straight sections83arranged adjacent the yoke141in the radial direction. In other words, non-conductive members (i.e., the sealing members57) preferably each occupy three-fourths of a dimension (i.e., thickness) T1(i.e., twice the thickness of the conductors82, in other words, a minimum distance between the surface320of the conductor group81placed in contact with the stator core52and the surface330of the conductor group81facing the rotor40) of the conductor groups (i.e., conductors)81in the radial direction of the stator winding51(i.e., the stator core52). Such selection of the thickness of the protrusions142causes each of the protrusions142not to function as a tooth between the conductor groups81(i.e., the straight sections83) arranged adjacent each other in the circumferential direction, so that there are no magnetic paths which would usually be formed by the teeth. The protrusions142need not necessarily to be arranged between a respective circumferentially adjacent two of all the conductor groups81, but however, a single protrusion142may be disposed at least only between two of the conductor groups81which are arranged adjacent each other in the circumferential direction. For instance, the protrusions142may be disposed away from each other in the circumferential direction at equal intervals each of which corresponds to a given number of the conductor groups81. Each of the protrusions142may be designed to have any shape, such as a rectangular or arc-shape. The straight sections83may alternatively be arranged in a single layer on the outer peripheral surface of the stator core52. In a broad sense, the thickness of the protrusions142from the yoke141in the radial direction may be smaller than half that of the straight sections83in the radial direction. If an imaginary circle whose center is located at the axial center of the rotating shaft11and which passes through the radial centers of the straight sections83placed adjacent the yoke141in the radial direction is defined, each of the protrusions142may be shaped to protrude only within the imaginary circle, in other words, not to protrude radially outside the imaginary circle toward the rotor40. The above structure in which the protrusions142have the limited thickness in the radial direction and do not function as teeth in the gaps between the straight sections83arranged adjacent each other in the circumferential direction enables the adjacent straight sections83to be disposed closer to each other as compared with a case where teeth are provided in the gaps between the straight sections83. This enables a sectional area of the conductor body82ato be increased, thereby reducing heat generated upon excitation of the stator winding51. The absence of the teeth enables magnetic saturation to be eliminated to increase the amount of electrical current delivered to the stator winding51. It is, however, possible to alleviate the adverse effects arising from an increase in amount of heat generated by the increase in electrical current delivered to the stator winding51. The stator winding51, as described above, has the turns84which are shifted in the radial direction and equipped with the interference avoiding portions with the adjacent turns84, thereby enabling the turns84to be disposed away from each other in the radial direction. This enhances the heat dissipation from the turns84. The above structure is enabled to optimize the heat dissipating ability of the stator50. The radial thickness of the protrusions142may not be restricted by the dimension H1inFIG.25as long as the yoke141of the stator core52and the magnet unit42(i.e., each of the magnets91and92) of the rotor40are arranged at a given distance away from each other. Specifically, the radial thickness of the protrusions142may be larger than or equal to the dimension H1inFIG.25as long as the yoke141and the magnet unit42arranged 2 mm or more away from each other. For instance, in a case where the radial thickness of the straight section83is larger than 2 mm, and each of the conductor groups81is made up of the two conductors82stacked in the radial direction, each of the protrusions142may be shaped to occupy a region ranging to half the thickness of the straight section83not contacting the yoke141, i.e., the thickness of the conductor82located farther away from the yoke141. In this case, the above beneficial advantages will be obtained by increasing the conductive sectional area of the conductor groups81as long as the radial thickness of the protrusions142is at least H1×3/2. The stator core52may be designed to have the structure illustrated inFIG.26.FIG.26omits the sealing members57, but the sealing members57may be used.FIG.26illustrates the magnet unit42and the stator core52as being arranged linearly for the sake of simplicity. In the structure ofFIG.26, the stator50has the protrusions142as conductor-to-conductor members each of which is arranged between a respective two of the conductors82(i.e., the straight sections83) located adjacent each other in the circumferential direction. The stator50is equipped with the portions350each of which magnetically operates along with one of the magnetic poles (i.e., an N-pole or an S-pole) of the magnet unit42when the stator winding51is excited. The portions350extend in the circumferential direction of the stator50. If each of the portions350has a length Wn in the circumferential direction of the stator50, the sum of widths of the protrusions142lying in a range of this length Wn (i.e., the total dimension of the protrusions412in the circumferential direction of the stator50in the range of length Wn) is defined as Wt, the saturation magnetic flux density of the protrusions412is defined as Bs, a width of the magnet unit42equivalent to one of the magnetic poles of the magnet unit42in the circumferential direction of the magnet unit42is defined as Wm, and the remanent flux density in the magnet unit42is defined as Br, the protrusions142are made of a magnetic material meeting a relation of Wt×Bs≤Wm×Br(1) The range Wn is defined to contain ones of the conductor groups81which are arranged adjacent each other in the circumferential direction and which overlap in time of excitation thereof with each other. It is advisable that a reference (i.e., a border) used in defining the range Wn be set to the center of the gap56between the conductor groups81. For instance, in the structure illustrated inFIG.26, the plurality of conductor groups81lying in the range Wn include the first, the second, the third, and the fourth conductor groups81where the first conductor group81is closest to the magnetic center of the N-pole. The range Wn is defined to include the total of those four conductor groups81. Ends (i.e., outer limits) of the range Wn are defined to lie at the centers of the gaps56. InFIG.26, the range Wn contains half of the protrusion142inside each of the ends thereof. The total of the four protrusions142lie in the range Wn. If the width of each of the protrusions142(i.e., a dimension of the protrusion142in the circumferential direction of the stator50, in other words, an interval between the adjacent conductor groups81) is defined as A, the sum of widths Wt of the protrusions142lying in the range Wn meets a relation of Wt=½A+A+A+A+½A=4A. Specifically, the three-phase windings of the stator winding51in this embodiment are made in the form of distributed windings. In the stator winding51, the number of the protrusions142for each pole of the magnet unit42, that is, the number of the gaps56each between the adjacent conductor groups81is selected to be “the number of phases×Q” where Q is the number of the conductors82for each phase which are placed in contact with the stator core52. In other words, in the case where the conductors82are stacked in the radial direction of the rotor40to constitute each of the conductor groups81, Q is the number of inner ones of the conductors82of the conductor groups81for each phase. In this case, when the three-phase windings of the stator winding51are excited in a given sequence, the protrusions142for two of the three-phases within each pole are magnetically excited. The total circumferential width Wt of the protrusions142excited upon excitation of the stator winding51within a range of each pole of the magnet unit42, therefore, meets a relation of “the number of the phases excited×Q×A=2×2×A where A is the width of each of the protrusions142(i.e., the gap56) in the circumferential direction. The total width Wt is determined in the above way. Additionally, the protrusions142of the stator core52are made of magnetic material meeting the above equation (1). The total width Wt is also viewed as being equivalent to a circumferential dimension of where the relative magnetic permeability is expected to become greater than one within each pole. The total width Wt may alternatively be determined as a circumferential width of the protrusions142in each pole with some margin. Specifically, since the number of the protrusions142for each pole of the magnet unit42is given by the number of phases×Q, the width of the protrusions412in each pole (i.e., the total width Wt) may be given by the number of phases×Q×A=3×2×A=6A. The distributed winding, as referred to herein, means that there is a pair of poles (i.e., the N-pole and the S-pole) of the stator winding51for each pair of magnetic poles. The pair of poles of the stator winding51, as referred to herein, is made of the two straight sections83in which electrical current flows in opposite directions and the turn84electrically connecting them together. Note that a short pitch winding or a full pitch winding may be viewed as an equivalent of the distributed winding as long as it meets the above conditions. Next, the case of a concentrated winding will be described below. The concentrated winding, as referred to herein, means that the width of each pair of magnetic poles is different from that of each pair of poles of the stator winding51. An example of the concentrated winding includes a structure in which there are three conductor groups81for each pair of magnetic poles, in which there are three conductor groups81for two pairs of magnetic poles, in which there are nine conductor groups81for four pairs of magnetic poles, or in which there are nine conductor groups81for five pairs of magnetic poles. In the case where the stator winding51is made in the form of the concentrated winding, when the three-phase windings of the stator winding51are excited in a given sequence, a portion of the stator winding51for two phases is excited. This causes the protrusions142for two phases to be magnetically excited. The circumferential width Wt of the protrusions142which is magnetically excited upon excitation of the stator winding in a range of each pole of the magnet unit42is given by Wt=A×2. The width Wt is determined in this way. The protrusions142are made of magnetic material meeting the above equation (1). In the above described case of the concentrated winding, the sum of widths of the protrusions142arranged in the circumferential direction of the stator50within a region surrounded by the conductor groups81for the same phase is defined as A. The dimension Wm in the concentrated winding is given by [an entire circumference of a surface of the magnet unit42facing the air gap]×[the number of phases]÷[the number of the distributed conductor groups81]. Usually, a neodymium magnet, a samarium-cobalt magnet, or a ferrite magnet whose value of BH is higher than or equal to 20[MGOe (kJ/m{circumflex over ( )}3)] has Bd=1.0T or more. Iron has Br=2.0T or more. The protrusions142of the stator core52may, therefore, be made of magnetic material meeting a relation of Wt<½×Wm for realizing a high-power motor. In a case where each of the conductors82is, as described later, equipped with the outer coated layer182, the conductors82may be arranged in the circumferential direction of the stator core with the outer coated layers182placed in contact with each other. In this case, the width Wt may be viewed to be zero or equivalent to thicknesses of the outer coated layers182of the conductors82contacting with each other. The structure illustrated inFIG.25or26is designed to have conductor-to-conductor members (i.e., the protrusions142) which are too small in size for the magnet-produced magnetic flux in the rotor40. The rotor40is implemented by a surface permanent magnet rotor which has a flat surface and a low inductance, and does not have a salient pole in terms of a magnetic resistance. Such a structure enables the inductance of the stator50to be decreased, thereby reducing a risk of distortion of the magnetic flux caused by the switching time gap in the stator winding51, which minimizes the electrical erosion of the bearings21and22. Second Modification The stator50equipped with the conductor-to-conductor members made to meet the above equation may be designed to have the following structure. InFIG.27, the stator core52is equipped with the teeth143as conductor-to-conductor members which are formed in an outer peripheral portion (an upper portion, as viewed in the drawing) of the stator core52. The teeth143protrude from the yoke141and are arranged at a given interval away from each other in the circumferential direction of the stator core52. Each of the teeth143has a thickness identical with that of the conductor group81in the radial direction. The teeth143have side surfaces placed in contact with the conductors82of the conductor groups81. The teeth143may alternatively be located away from the conductors82through gaps. The teeth143are shaped to have a restricted width in the circumferential direction. Specifically, each of the teeth143has a stator tooth which is very thin for the volume of magnets. Such a structure of the teeth143serves to achieve saturation by the magnet-produced magnetic flux at 1.8T or more to reduce the permeance, thereby decreasing the inductance. If a surface area of a magnetic flux-acting surface of the magnet unit42facing the stator50for each pole is defined as Sm, and the remanent flux density of the magnet unit42is defined as Br, the magnetic flux in the magnet unit42will be Sm×Br. A surface area of each of the teeth143facing the rotor40is defined as St. The number of the conductors83for each phase is defined as m. When the teeth143for two phases within a range of one pole are magnetically excited upon excitation of the stator winding51, the magnetic flux in the stator50is expressed by St×m×2×Bs. The decrease in inductance may be achieved by selecting the dimensions of the teeth143to meet a relation of St×m×2×Bs<Sm×Br(2). In a case where the dimension of the magnet unit42is identical with that of the teeth143in the axial direction, the above equation (2) may be rewritten as an equation (3) of Wst×m×2×Bs<Wm×Br where Wm is the circumferential width of the magnet unit42for each pole, and Wst is the circumferential width of the teeth143. For example, when Bs=2T, Br=1T, and m=2, the equation (3) will be Wst<Wm/8. In this case, the decrease in inductance may be achieved by selecting the width Wst of the teeth143to be smaller than one-eighth (⅛) of the width Wm of the magnet unit42for one pole. When m is one, the width Wst of the teeth143is preferably selected to be smaller than one-fourth (¼) of the width Wm of the magnet unit42for one pole. “Wst×m×2” in the equation (3) corresponds to a circumferential width of the teeth143magnetically excited upon excitation of the stator winding51in a range of one pole of the magnet unit42. The structure inFIG.27is, like inFIGS.25and26, equipped with the conductor-to-conductor members (i.e., the teeth143) which are very small in size for the magnet-produced magnetic flux in the rotor40. Such a structure is capable of reducing the inductance of the stator50to alleviate a risk of distortion of the magnetic flux arising from the switching time gap in the stator winding51, which minimizes the probability of the electrical erosion of the bearings21and22. Third Modification The above embodiment has the sealing members57which cover the stator winding51and occupy a region including all of the conductor groups81radially outside the stator core52, in other words, lie in a region where the thickness of the sealing members57is larger than that of the conductor groups81in the radial direction. This layout of the sealing members57may be changed. For instance, the sealing members57may be, as illustrated inFIG.28, designed so that the conductors82protrude partially outside the sealing members57. Specifically, the sealing members57are arranged so that portions of the conductors82that are radially outermost portions of the conductor groups81are exposed outside the sealing members57toward the stator50. In this case, the thickness of the sealing members57in the radial direction may be identical with or smaller than that of the conductor groups81. Fourth Modification The stator50may be, as illustrated inFIG.29, designed not to have the sealing members57covering the conductor groups81, i.e., the stator winding51. In this case, a gap is created between the adjacent conductor groups81arranged in the circumferential direction without a conductor-to-conductor member therebetween. In other words, no conductor-to-conductor member is disposed between the conductor groups81arranged in the circumferential direction. Air may be arranged in the gaps between the conductor groups81. The air may be viewed as a non-magnetic member or an equivalent thereof whose Bs is zero (0). Fifth Modification The conductor-to-conductor members of the stator50may be made of a non-magnetic material other than resin. For instance, a non-metallic material, such as SUS304 that is austenitic stainless steel. Sixth Modification This modification has a partially altered moulded structure for the stator winding51. This modification and following modifications of the moulded structure for the stator winding51will refer only to parts different from those already described with reference toFIGS.10and11. The stator core52is, as clearly illustrated inFIG.30, arranged inside an inner periphery of the stator winding51(i.e., an opposite side of the stator winding51than to the magnet unit42). The stator core52has a surface which faces the stator winding51and on which concavities and convexities are formed successively in a circumferential direction thereof. The concavities define the recesses151which are filled with molding material. The molding material which forms the sealing members57enters the recesses151. The molding material in the recesses151composes portions of the sealing members57. The concavities and convexities may be formed by knurling. The concavities and convexities of the surface (e.g., knurled surface) of the stator core52may alternatively be arranged successively adjacent each other only in the axial direction or both in the axial direction and in the circumferential direction. In this structure, molding materials are disposed intermittently between the stator winding51and the stator core52, thereby minimizing misalignment of the molding materials with the stator core52, in other words, holding the sealing members57which surround the conductor groups81from moving. This eliminates a risk of misalignment of the stator winding51. When the concavities and convexities are arranged successively on the stator core52in the axial direction thereof, it minimizes misalignment of the stator winding51in the axial direction. Alternatively, when the concavities and convexities are arranged successively on the stator core52in the circumferential direction thereof, it minimizes misalignment of the stator winding51in the circumferential direction. Seventh Modification This modification has a partially altered moulded structure for the stator winding51. In the structure inFIG.31, the stator core52has a plurality of steel plates52awhose outer edges offset from each other to have concavities and convexities on an outer peripheral surface of the stator core52which are arranged successively in the axial direction. Molding materials are disposed in the recesses152defined by the concavities and the convexities. The structure may have a stack of steel plates52awhich are different in outer diameter from each other. Eighth Modification This modification has a partially altered moulded structure for the stator winding51. In the structure illustrated inFIG.32, each of the steel plates52ahas an end which faces the stator winding51and has a cross-section tapered in a thickness-wise direction. The tapered ends of the steel plates52adefine successive recesses in which molding materials are disposed. The stator core52made of a stack of steel plates has a concern about generation of eddy current in the steel plates52awhen subjected to a strong magnetic field. Such a concern will usually be strong on the ends of the steel plates52aclose to the stator winding51. The above structure in which the steel plates52ahave the tapered ends close to the stator winding51, however, minimizes the generation of eddy current. Ninth Modification This modification has a partially altered moulded structure for the stator winding51. The structure illustrated inFIG.33has the insulating layer155disposed between the stator winding51and the stator core52. The insulating layer155is made from resin. The structure in this modification serves to block a flow of electrical current arising from an electromagnetic field exerted by the stator winding51on the stator core52, thereby achieving a suitable electrical erosion avoiding measure. Tenth Modification This modification has a partially altered moulded structure for the stator winding51. The structure illustrated inFIG.34has the stator core52in which the resin-injecting holes156are formed. The resin-injecting holes156extend in the axial direction and are each filled with a molding material (i.e., resin). The resin-injecting holes156are through-holes extending from one end to the other end of the stator core52in the axial direction and arranged at a given interval away from each other in the circumferential direction. This keeps molded members (i.e., the sealing members57) arranged at fixed locations in the circumferential and axial directions, thereby improving the structure to minimize misalignment of the stator winding51. The resin-injecting holes156of the stator core52are located away from the stator winding51in the radius direction, thereby reducing adverse effects on the magnetic circuits to ensure the stability in operation of the rotating electrical machine10. In the stator core52made of a stack of steel plates, burrs of the steel plates usually make irregularities on peripheral surfaces of the resin-injecting holes156. The molding material enters the irregularities, which function as anchors to hold the stator winding51from being misaligned. Each of the resin-injecting holes156may alternatively be implemented by a hole not extending through the stator core52in the axial direction. In the structure illustrated inFIG.34, the stator winding51is covered with or embedded in a molding material except portions extending in the axial direction or the radial direction. In other words, portions of the stator winding51are exposed outside the molding material. More specifically, the coil ends54and55(i.e., axially-opposed ends) of the stator winding51are partially exposed outside the molding material. The stator winding51may alternatively be designed only to have portions extending in the radial direction outside the molding material (seeFIG.28). The stator winding51, therefore, has the above described advantage that the stator winding51is held by the mold from being misaligned, and the portions of the stator winding51which are not embedded in the mold serve to enhance a cooling effect. It is, therefore, possible to achieve both the misalignment reducing effect and the cooling effect. The rotating electrical machine10may have a structure to cool a motor housing using cooling wind produced by rotation of the rotating shaft11and the rotor40or cool the stator50using a liquid cooling medium. In this case, the stator winding51has portions exposed outside the molding material (i.e., the sealing members57), so that the exposed portions are cooled by air or cooling medium, thereby enhancing the cooled ability of the stator winding51. Eleventh Modification This modification has a partially altered moulded structure for the stator winding51. In the structure illustrated inFIG.35, the insulating layer157made from resin is disposed between the stator core52and the unit base61. This structure serve to block a flow of electrical current arising from an electromagnetic field exerted by the stator core51on the unit base61, thereby achieving a suitable electrical erosion avoiding measure. Twelfth Modification In this modification, the rotor40serving as a magnetic field-producing unit has a skew structure. Specifically, the rotor40has the magnet unit42designed to have the skew structure in which magnetic poles which are arranged in the axial direction of the rotating shaft11are offset from each other in the circumferential direction of the rotor40. Particularly, the magnetic poles of the magnet unit42have respective magnetic pole center lines each of which extends in the axial direction and which is skewed by either a first amount in a first circumferential direction of the rotor40or a second amount in a second circumferential direction opposite the first circumferential direction of the rotor40. The first and second amounts (which will also be referred to as skew amounts) are identical with each other. The skew structure of the rotor40will be described below in detail with reference toFIGS.36(a) and36(b).FIGS.36(a) and36(b)are front views schematically illustrating locations of the magnets91having given magnetic poles. The skew structure in each ofFIGS.36(a) and36(b)has axially-opposed end portions and a middle portion between the end portions. Each of the end portions and the middle portion are different in skew orientation from each other in the form of a so-called V-shaped skew. The structure inFIG.36(a)is a skew structure in which locations of the magnets91in the circumferential direction are misaligned to be stepwise in the axial direction. The structure has two first portions B1that are axially-opposed ends and a second portion B2intermediate between the first portions B1. The first portions B1are different in circumferential location from the second portion B2. In each of the first portions B1, the circumferential location of the magnet91is offset leftward, as viewed in the drawing, from the magnetic pole center line LA. In the second portion B2, the circumferential location of the magnet91is offset rightward, as viewed in the drawing, from the magnetic pole center line LA. The skew amount L1of each of the first portions B1from the magnetic pole center line LA in the first circumferential direction is identical with the skew amount L2of the second portions B2from the magnetic pole center line LA in the second circumferential direction opposite the first circumferential direction. The first portions B1have a length in the axial direction which is identical with that of the second portion B2. Each of the skew amounts L1and L2is given by a distance between the magnetic pole center line LA and the center line of the magnet91in the circumferential direction. Each of the first portions B1has a length in the axial direction which is half that of the second portion B2. The structure inFIG.36(b)is a skew structure in which a circumferential location of each of the magnets91is changed obliquely in the axial direction. The structure has a first portion B11given by one of axially opposed ends thereof and a second portion B12given by the other end. Directions in which the first portion B11and the second portion B12are inclined are oriented to be different from each other relative to the axial direction. The first portion B11and the second portion B12are symmetric with respect to an axial boundary line of the first and second portions B11and B12. Each of the first and second portions B11and B12has a magnet unit center line LB extending obliquely in a skew direction. The magnet unit center lines LB of the first and second portions B11and B12intersect with the magnetic pole center line LA at the axial center positions P1and P2, respectively. The angles θ1and θ2at which the magnets91are inclined in the first portion B11and the second portion B12are identical with each other. The structure in which the rotor40is skewed is expected to offer an effect of reducing torque ripple and a resulting effect of improving noise-reduction, but has a concern about electrical erosion of the bearings21and22arising from unbalance of magnetic fluxes in the axial direction. The above structure is designed to have the equal first and second skew amounts from the magnetic pole center line LA of each magnetic pole extending in the axial direction in the magnet unit42, thereby cancelling electrical currents flowing in the axial direction. This minimizes a risk of electrical erosion of the bearings21and22. Thirteenth Modification This modification has the stator50serving as an armature which is designed to be of a skew structure. Specifically, the rotor50has the skew structure in which conductor locations of the stator winding51for each phase in the axial direction of the rotating shaft11are offset in the circumferential direction. A first amount by which each of the phase windings of the stator winding51is skewed in a first circumferential direction from an energized phase center line extending in the axial direction is selected to be identical with a second amount by which each of the phase windings of the stator winding51for each phase is skewed in a second circumferential direction oppose the first circumferential direction from the energized phase center line. The skew structure of the stator50will be described below in detail with reference toFIGS.37(a) and37(b).FIGS.37(a) and37(b)are front views schematically illustrating layout of the conductors82for a given phase. The stator winding51is required to have the conductors82connected continuously together. The skew structure is, therefore, employed in which conductor locations of the stator winding51for each phase are changed obliquely in the circumferential direction. The structure illustrated inFIG.37(a)is designed as a skew structure in which each of the conductors82has a magnet-facing portion (i.e., a coil side) which is bent or turned back. The conductor82includes a first section C1and a second section C2which are different in inclined orientation of the conductor82from each other in the axial direction. The first and second sections C1and C2are vertically symmetric with each other with respect to the axially center point of the stator50. The first and second sections C1and C2have centers P11and P12of axial lengths thereof which intersect with the energized phase center line LC extending in the axial direction. The structure illustrated inFIG.37(b)is designed as a skew structure in which each of the conductors82has a magnet-facing portion (i.e., a coil side) which is not turned back, in other words, the magnet-facing portion of the conductor82extend obliquely straight. The conductor82, as indicated by a solid line inFIG.37(b), is a conductor of an outer one of two layers of the stator winding51which are arranged adjacent each other in the radial direction. The conductor82, as indicated by a broken line inFIG.37(b), is a conductor of an inner one of the two layers. The conductor82of the outer layer is skewed in a direction opposite that in which the conductor82of the inner layer is skewed. The conductor82of each of the outer and inner layers has an axial center P13intersecting with the energized phase center line LC. The structure in which the stator50is skewed is expected to offer an effect of reducing torque ripple, but has a concern about electrical erosion of the bearings21and22arising from promoted unbalance of magnetic fluxes in the axial direction. The above structure is designed to have the first and second skew amounts by which the phase windings of the stator winding51are skewed in the first and second circumferential directions from the energized phase center line LC extending in the axial direction and which are equal to each other, thereby cancelling electrical currents flowing in the axial direction. This minimizes a risk of electrical erosion of the bearings21and22. Both the rotor40and the stator50may be designed to have the skew structure. In other words, the structures inFIGS.36(a) and36(b)andFIGS.37(a) and37(b)may be combined. The rotating electrical machine10described in the first embodiment has the rotor40and the stator50which are both designed as a non-skew structure which does not offer an effect of reduction in the torque ripple which usually results from the skew, but has an advantage that the imbalance of magnetic fluxes arising from the skew does not occur. Fourteenth Modification The stator50may be designed not to have the stator core52. Specifically, the stator50is made of the stator winding51shown inFIG.12. The stator winding51of the stator50may be covered with a sealing member. The stator50may alternatively be designed to have an annular winding retainer made from non-magnetic material such as synthetic resin instead of the stator core52made from soft magnetic material. Fifteenth Modification The structure in the first embodiment uses the magnets91and92arranged in the circumferential direction to constitute the magnet unit42of the rotor40. The magnet unit42may be made using a circular ring-shaped permanent magnet. For instance, the arc-shaped or annular magnet95is, as illustrated inFIG.38, secured to a radially inner periphery of the cylinder43of the magnet holder41. The annular magnet95is equipped with a plurality of different magnetic poles whose polarities are arranged alternately in the circumferential direction of the annular magnet95. The magnet95lies integrally both on the d-axis and the q-axis. The annular magnet95has a magnetic orientation directed in the radial direction on the d-axis of each magnetic pole and a magnetic orientation directed in the circumferential direction on the q-axis between the magnetic poles, thereby creating arc-shaped magnetic paths. The annular magnet95may be magnetically oriented to create the arc-shaped magnet-produced magnetic path in which the easy axis of magnetization is directed parallel or near parallel to the d-axis in the region close to the d-axis and also directed perpendicular or near perpendicular to the q-axis in the region close to the q-axis. Sixteenth Modification This modification is different in operation of the controller110from the above embodiment or modifications. Only differences from those in the first embodiment will be described below. The operations of the operation signal generators116and126illustrated inFIG.20and the operation signal generators130aand130billustrated inFIG.21will first be discussed below usingFIG.39. The operations executed by the operation signal generators116,126,130a, and130bare basically identical with each other. Only the operation of the operation signal generator116will, therefore, be described below for the sake of simplicity. The operation signal generator116includes the carrier generator116a, the U-phase comparator116bU, the V-phase comparator116bV, and the W-phase comparator116bW. The carrier generator116aproduces and outputs the carrier signal SigC in the form of a triangle wave signal. The U-, V-, and W-phase comparators116bU,116bV, and116bW receive the carrier signal SigC outputted by the carrier generator116aand the U-, V-, and W-phase command voltages produced by the three-phase converter115. The U-, V-, and W-phase command voltages are produced, for example, in the form of a sine wave and outputted 120° out of electrical phase with each other. The U-, V-, and W-phase comparators116bU,116bV, and116bW compare the U-, V-, and W-phase command voltages with the carrier signal SigC to produce operation signals for the switches Sp and Sn of the upper and lower arms in the first inverter101for the U-, V-, and W-phase windings under PWM (Pulse Width Modulation) control. Specifically, the operation signal generator116works to produce operation signals for the switches Sp and Sn of the upper and lower arms for the U-, V-, and W-phase windings under the PWM control based on comparison of levels of signals derived by normalizing the U-, V-, and W-phase command voltages using the power supply voltage with a level of the carrier signal SigC. The driver117is responsive to the operation signals outputted by the operation signal generator116to turn on or off the switches Sp and Sn in the first inverter101for the U-, V-, and W-phase windings. The controller110alters the carrier frequency fc of the carrier signal SigC, i.e., a switching frequency for each of the switches Sp and Sn. The carrier frequency fc is altered to be higher in a low torque range or a high-speed range in the rotating electrical machine10and alternatively lower in a high torque range in the rotating electrical machine10. This altering is achieved in order to minimize a deterioration in ease of control of electrical current flowing through each of the U-, V-, and W-phase windings. In brief, the core-less structure of the stator50serves to reduce the inductance in the stator50. The reduction in inductance usually results in a decrease in electrical time constant in the rotating electrical machine10. This leads to a risk that a ripple of current flowing through each of the phase windings may be increased, thereby resulting in the deterioration in ease of control of the current flowing through the phase winding, which causes control divergence. The adverse effects of the above deterioration of the ease of control usually become higher when the current (e.g., an effective value of the current) flowing through the winding lies in a low current region than when the current lies in a high current range. In order to alleviate such a problem, the controller110in this embodiment is designed to alter the carrier frequency fc. How to alter the carrier frequency fc will be described below with reference toFIG.40. This operation of the operation signal generator116is executed by the controller110cyclically at a given interval. First, in step S10, it is determined whether electrical current flowing through each of the three-phase windings51alies in the low current range. This determination is made to determine whether torque now produced by the rotating electrical machine10lies in the low torque range. Such a determination may be achieved according to the first method or the second method, as discussed below. First Method The estimated torque value of the rotating electrical machine10is calculated using the d-axis current and the q-axis current converted by the d-q converter112. If the estimated torque value is determined to be lower than a torque threshold value, it is concluded that the current flowing through the winding51alies in the low current range. Alternatively, if the estimated torque value is determined to be higher than or equal to the torque threshold value, it is concluded that the current lies in the high current range. The torque threshold value is selected to be half, for example, the degree of starting torque (also called locked rotor torque) in the rotating electrical machine10. Second Method If an angle of rotation of the rotor40measured by an angle sensor is determined to be higher than or equal to a speed threshold value, it is determined that the current flowing through the winding51alies in the low current range, that is, in the high speed range. The speed threshold value may be selected to be a rotational speed of the rotating electrical machine10when a maximum torque produced by the rotating electrical machine10is equal to the torque threshold value. If a NO answer is obtained in step S10, meaning that the current lies in the high current range, then the routine proceeds to step S11wherein the carrier frequency fc is set to the first frequency fL. Alternatively, if a YES answer is obtained in step S10, then the routine proceeds to step S12wherein the carrier frequency fc is set to the second frequency fH that is higher than the first frequency fL. As apparent from the above discussion, the carrier frequency fc when the current flowing through each of the three-phase windings lies in the low current range is selected to be higher than that when the current lies in the high current range. The switching frequency for the switches Sp and Sn is, therefore, increased in the low current range, thereby minimizing a rise in current ripple to ensure the stability in controlling the current. When the current flowing through each of the three-phase windings lies in the high current range, the carrier frequency fc is selected to be lower than that when the current lies in the low current range. The current flowing through the winding in the high current range usually has an amplitude larger than that when the current lies in the low current range, so that the rise in current ripple arising from the reduction in inductance has a low impact on the ease of control of the current. It is, therefore, possible to set the carrier frequency fc in the high current range to be lower than that in the low current range, thereby reducing a switching loss in the inverters101and102. This modification is capable of realizing the following modes. If a YES answer is obtained in step S10inFIG.40when the carrier frequency fc is set to the first frequency fL, the carrier frequency fc may be changed gradually from the first frequency fL to the second frequency fH. Alternatively, if a NO answer is obtained in step S10when the carrier frequency fc is set to the second frequency fH, the carrier frequency fc may be changed gradually from the second frequency fH to the first frequency fL. The operation signals for the switches may alternatively be produced using SVM (Space Vector Modulation) instead of the PWM. The above altering of the switching frequency may also be made. Seventeenth Modification In each of the embodiments, two pairs of conductors making up the conductor groups81for each phase are, as illustrated inFIG.41(a), arranged parallel to each other.FIG.41(a)is a view which illustrates an electrical connection of the first and second conductors88aand88bthat are the two pairs of conductors. The first and second conductors88aand88bmay alternatively be, as illustrated inFIG.41(b), connected in series with each other instead of the connection inFIG.41(a). Three or more pairs of conductors may be stacked in the form of multiple layers.FIG.42illustrates four pairs of conductors: the first to fourth conductors88ato88dwhich are stacked. The first conductor88a, the second conductor88b, the third conductor88c, and the fourth conductor88dare arranged in this order from the stator core52in the radial direction. The third and fourth conductors88cand88dare, as illustrated inFIG.44(c), connected in parallel to each other. The first conductor88ais connected to one of joints of the third and fourth conductors88cand88d. The second conductor88bis connected to the other joint of the third and fourth conductors88cand88d. The parallel connection of conductors usually results in a decrease in current density of those conductors, thereby minimizing thermal energy produced upon energization of the conductors. Accordingly, in the structure in which a cylindrical stator winding is installed in a housing (i.e., the unit base61) with the coolant path74formed therein, the first and second conductors88aand88bwhich are connected in non-parallel to each other are arranged close to the stator core52placed in contact with the unit base61, while the third and fourth conductors88cand88dwhich are connected in parallel to each other are disposed farther away from the stator core52. This layout equalizes the cooling ability of the conductors88ato88dstacked in the form of multiple layers. The conductor group81including the first to fourth conductors88ato88dmay have a thickness in the radial direction which is smaller than a circumferential width of the conductor groups81for one phase within a region of one pole. Eighteenth Modification The rotor40of the rotating electrical machine10may be designed as described below. InFIG.43(a), the cylinder43of the magnet holder41is equipped with the back core48made of a stack of magnetic steel plates. The magnet unit42is arranged radially inside the back core48. More specifically, the back core48has the housing recess48awhich is defined inside an inner periphery thereof and in which the magnet unit42is stored. The magnet unit42is disposed fully or partially inside the housing recess48awith axially opposed end surfaces thereof placed in contact with the back core48. This structure minimizes leakage of magnetic flux from the axially opposed ends of the magnet unit42and also greatly enhances a resistance to demagnetization thereof, which results from a reduction in magnetic resistance of iron. Nineteenth Modification The rotating electrical machine10may alternatively be designed to have an inner rotor structure (i.e., an inward rotating structure). In this case, the stator50may be mounted, for example, on a radial outside within the housing30, while the rotor40may be disposed on a radial inside within the housing30. The inverter unit60may be mounted one or both axial sides of the stator50or the rotor40.FIG.44is a transverse sectional view of the rotor40and the stator50.FIG.45is an enlarged view which partially illustrates the rotor40and the stator50inFIG.44. The inner rotor structure inFIGS.44and45is substantially identical with the outer rotor structure inFIGS.8and9except for the layout of the rotor40and the stator50in the radial direction. In brief, the stator50is equipped with the stator winding51having the flattened conductor structure and the stator core52with no teeth. The stator winding51is installed radially inside the stator core52. The stator core52, like the outer rotor structure, has any of the following structures. (A) The stator50has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. As the conductor-to-conductor members, magnetic material is used which meets a relation of Wt×Bs≤Wm×Br where Wt is a width of the conductor-to-conductor members in the circumferential direction within one magnetic pole, Bs is the saturation magnetic flux density of the conductor-to-conductor members, Wm is a width of the magnet unit equivalent to one magnetic pole in the circumferential direction, and Br is the remanent flux density in the magnet unit. (B) The stator50has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. The conductor-to-conductor members are each made of a non-magnetic material. (C) The stator50has no conductor-to-conductor member disposed between the conductor portions in the circumferential direction. The same is true of the magnets91and92of the magnet unit42. Specifically, the magnet unit42is made up of the magnets91and92each of which is magnetically oriented to have the easy axis of magnetization which is directed near the d-axis to be more parallel to the d-axis than that near the q-axis which is defined on the boundary of the magnetic poles. The details of the magnetization direction in each of the magnets91and92are the same as described above. The magnet unit42may be the annular magnet95(seeFIG.38). FIG.46is a longitudinal sectional view of the rotating electrical machine10designed to have the inner rotor structure.FIG.46corresponds toFIG.2. Differences from the structure inFIG.2will be described below in brief. InFIG.46, the annular stator50is retained inside the housing30. The rotor40is disposed inside the stator50with an air gap therebetween to be rotatable. The bearings21and22are, like inFIG.2, offset from the axial center of the rotor40to one of axially-opposed ends of the rotor40, so that the rotor40is retained in the cantilever form. The inverter60is mounted inside the magnet holder41of the rotor40. FIG.47illustrates the inner rotor structure of the rotating electrical machine10which is different from that described above. The housing30has the rotating shaft11retained by the bearings21and22to be rotatable. The rotor40is secured to the rotating shaft11. Like the structure inFIG.2, each of the bearings21and22is offset from the axial center of the rotor40in the axial direction of the rotor40. The rotor40is equipped with the magnet holder41and the magnet unit42. The rotating electrical machine10inFIG.47is different from that inFIG.46in that the inverter unit60is not located radially inside the rotor40. The magnet holder41is joined to the rotating shaft11radially inside the magnet unit42. The stator50is equipped with the stator winding51and the stator core52and secured to the housing30. Twentieth Modification This modification has the rotating shaft11equipped with an insulating layer which is disposed on an outer periphery thereof and has an outer periphery to which a rotor is secured. Specifically, the rotating shaft11, as clearly illustrated inFIG.48(a), has the insulating layer161wrapped fully about the whole of an outer periphery thereof. The rotor40is arranged outside the insulating layer161. The insulating layer161is made from, for example, a resinous material. The magnet holder41of the rotor40is attached to the rotating shaft11through the insulating layer161disposed between itself and the rotating shaft11. The rotating shaft11may alternatively be, as illustrated inFIG.48(b), designed to have a recess which is formed in the outer periphery thereof and in which the insulating layer161is disposed. The above structure serves to block an axial current flowing in the rotating shaft11using the insulating layer161, thereby minimizing a risk of electrical erosion. Twenty-First Modification The inner rotor structure of a rotating electrical machine which is different from that described above will be discussed below.FIG.49is an exploded perspective view of the rotating electrical machine200.FIG.50is a sectional side view of the rotating electrical machine200. In the following discussion, a vertical direction is based on the orientation of the rotating electrical machine200inFIGS.39and50. The rotating electrical machine200, as illustrated in FIGS.49and50, includes the stator203and the rotor204. The stator203is equipped with the annular stator core201and the multi-phase stator winding202. The rotor204is disposed inside the stator core201to be rotatable. The stator203works as an armature. The rotor204works as a field magnet. The stator core201is made of a stack of silicon steel plates. The stator winding202is installed in the stator core201. Although not illustrated, the rotor204is equipped with a rotor core and a plurality of permanent magnet arranged in the form of a magnet unit. The rotor core has formed therein a plurality of holes which are arranged at equal intervals away from each other in the circumferential direction of the rotor core. The permanent magnets which are magnetized to have magnetization directions changed alternately in adjacent magnetic poles are disposed in the holes of the rotor core. The permanent magnets of the magnet unit may be designed, like inFIG.23, to have a Halbach array structure or a similar structure. The permanent magnets of the magnet unit may alternatively be made of anisotropic magnets, as described with reference toFIG.9or30, in which the magnetic orientation (i.e., the magnetization direction) extends in an arc-shape between the d-axis which is defined on the magnetic center and the q-axis which is defined on the boundary of the magnetic poles. The stator203may be made to have one of the following structures. (A) The stator203has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. As the conductor-to-conductor members, magnetic material is used which meets a relation of Wt×Bs≤Wm×Br where Wt is a width of the conductor-to-conductor members in the circumferential direction within one magnetic pole, Bs is the saturation magnetic flux density of the conductor-to-conductor members, Wm is a width of the magnet unit equivalent to one magnetic pole in the circumferential direction, and Br is the remanent flux density in the magnet unit. (B) The stator203has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. The conductor-to-conductor members are each made of a non-magnetic material. (C) The stator203has no conductor-to-conductor member disposed between the conductor portions in the circumferential direction. The rotor204has the magnet unit which is made up of a plurality of magnets each of which is magnetically oriented to have the easy axis of magnetization which is directed near the d-axis to be more parallel to the d-axis than that near the q-axis which is defined on the boundary of the magnetic poles. The annular inverter case211is disposed on one end side of an axis of the rotating electrical machine200. The inverter case211has a lower surface placed in contact with an upper surface of the stator core201. The inverter case211has disposed therein a plurality of power modules212constituting an inverter circuit, the smoothing capacitors213working to reduce a variation in voltage or current (i.e., a ripple) resulting from switching operations of semiconductor switches, the control board214equipped with a controller, the current sensor215working to measure a phase current, and the resolver stator216serving as a rotational speed sensor for the rotor204. The power modules212are equipped with IGBTs serving as semiconductor switches and diodes. The inverter case211has the power connector217which is disposed on a circumferential edge thereof for connection with a dc circuit for a battery mounted in a vehicle. The inverter case211also has the signal connector218which is disposed on the circumferential edge thereof for achieving transmission of signals between the rotating electrical machine200and a controller installed in the vehicle. The inverter case211is covered with the top cover219. The dc power produced by the battery installed in the vehicle is inputted into the power connector217, converted by the switches of the power modules212to an alternating current, and then delivered to phase windings of the stator winding202. The bearing unit221and the annular rear case222are disposed on the opposite end side of the axis of the stator core to the inverter case211. The bearing unit221retains a rotation shaft of the rotor204to be rotatable. The rear case222has the bearing unit221disposed therein. The bearing unit221is equipped with, for example, two bearings and offset from the center of the length of the rotor204toward one of the ends of the length of the rotor204. The bearing unit221may alternatively be engineered to have a plurality of bearings disposed on both end sides of the stator core201opposed to each other in the axial direction, so that the bearings retain both the ends of the rotation shaft. The rear case222is fastened to a gear case or a transmission of the vehicle using bolts, thereby securing the rotating electrical machine200to the vehicle. The inverter case211has formed therein the cooling flow path211athrough which cooling medium flows. The cooling flow path211ais defined by closing an annular recess formed in a lower surface of the inverter case211by an upper surface of the stator core201. The cooling flow path211asurrounds a coil end of the stator winding202. The cooling flow path211ahas the module cases212aof the power modules212disposed therein. Similarly, the rear case222has formed therein the cooling flow path222awhich surrounds a coil end of the stator winding202. The cooling flow path222ais defined by closing an annular recess formed in an upper surface of the rear case222by a lower surface of the stator core201. Twenty-Second Modification The above discussion has referred to the revolving-field type of rotating electrical machines, but a revolving armature type of rotating electrical machine may be embodied.FIG.51illustrates the revolving armature type of rotating electrical machine230. The rotating electrical machine230inFIG.51has the bearing232retained by the housings231aand231b. The bearing232retains the rotating shaft233to be rotatable. The bearing232is made of, for example, an oil-impregnated bearing in which a porous metal is impregnated with oil. The rotating shaft233has secured thereto the rotor234which works as an armature. The rotor234includes the rotor core235and the multi-phase rotor winding236secured to an outer periphery of the rotor core235. The rotor core235of the rotor234is designed to have the slot-less structure. The multi-phase rotor winding236has the flattened conductor structure as described above. In other words, the multi-phase rotor winding236is shaped to have an area for each phase which has a dimension in the circumferential direction which is larger than that in the radial direction. The stator237is disposed radially outside the rotor234. The stator237works as a field magnet. The stator237includes the stator core238and the magnet unit239. The stator core238is secured to the housing231a. The magnet unit239is attached to an inner periphery of the stator core238. The magnet unit239is made up of a plurality of magnets arranged to have magnetic poles alternately arrayed in the circumferential direction. Like the magnet unit42described above, the magnet unit239is magnetically oriented to have the easy axis of magnetization which is directed near the d-axis to be more parallel to the d-axis than that near the q-axis that is defined on a boundary between the magnetic poles. The magnet unit239is equipped with magnetically oriented sintered neodymium magnets whose intrinsic coercive force is 400 [kA/m] or more and whose remanent flux density is 1.0 [T] or more. The rotating electrical machine230in this embodiment is engineered as a two-pole three-coil brush coreless motor. The multi-phase rotor winding236is made of three coils. The magnet unit239is designed to have two poles. A ratio of the number of poles and the number of coils in typical brush motors is 2:3, 4:10, or 4:21 depending upon intended use. The rotating shaft233has the commutator241secured thereto. A plurality of brushes242are arranged radially outside the commutator241. The commutator241is electrically connected to the multi-phase rotor winding236through the conductors234embedded in the rotating shaft233. The commutator241, the brushes242, and the conductors243are used to deliver dc current to the multi-phase rotor winding236. The commutator241is made up of a plurality of sections arrayed in a circumferential direction thereof depending upon the number of phases of the multi-phase rotor winding236. The brushes242may be connected to a dc power supply, such as a storage battery, using electrical wires or using a terminal block. The rotating shaft233has the resinous washer244disposed between the bearing232and the commutator241. The resinous washer244serves as a sealing member to minimize leakage of oil seeping out of the bearing232, implemented by an oil-impregnated bearing, to the commutator241. Twenty-Third Modification Each of the conductors82of the stator winding51of the rotating electrical machine10may be designed to have a stack of a plurality of insulating coatings or layers laid on each other. For instance, each of the conductors82may be made by covering a bundle of a plurality of insulating layer-coated conductors (i.e., wires) with an insulating layer, so that the insulating layer (i.e., an inner insulating layer) of each of the conductors82is covered with the insulating layer (i.e., an outer insulating layer) of the bundle. The outer insulating layer is preferably designed to have an insulating ability greater than that of the inner insulating layer. Specifically, the thickness of the outer insulating layer is selected to be larger than that of the inner insulating layer. For instance, the outer insulating layer has a thickness of 100 μm, while the inner insulating layer has a thickness of 40 μm. Alternatively, the outer insulating layer may have a permittivity lower than that of the inner insulating layer. Each of the conductors82may have any of the above structure. Each wire is preferably made of a collection of conductive members or fibers. As apparent from the above discussion, the rotating electrical machine10becomes useful in a high-voltage system of a vehicle by increasing the insulation ability of the outermost layer of the conductor82. The above structure enables the rotating electrical machine10to be driven in low pressure conditions such as highlands. Twenty-Fourth Modification Each of the conductors82equipped with a stack of a plurality of insulating layers may be designed to have at least one of a linear expansion coefficient and the degree of adhesion strength different between an outer one and an inner one of the insulating layers. The conductors82in this modification are illustrated inFIG.52. InFIG.52, the conductor82includes a plurality of (four in the drawing) wires181, the outer coated layer182(i.e., an outer insulating layer) with which the wires181are covered and which is made of, for example, resin, and the intermediate layer183(i.e., an intermediate insulating layer) which is disposed around each of the wires181within the outer coated layer182. Each of the wires181includes the conductive portion181amade of copper material and the conductor-coating layer (i.e., an inner insulating layer) made of electrical insulating material. The outer coated layer182serves to electrically insulate between phase-windings of the stator winding. Each of the wires181is preferably made of a collection of conductive members or fibers. The intermediate layer183has a linear expansion coefficient higher than that of the coated layer181b, but lower than that of the outer coated layer182. In other words, the linear expansion coefficient of the conductor82is increased from an inner side to an outer side thereof. Typically, the outer coated layer182is designed to have a linear expansion coefficient higher than that of the coated layer181b. The intermediate layer183, as described above, has a linear expansion coefficient intermediate between those of the coated layer181band the outer coated layer182and thus serves as a cushion to eliminate a risk that the inner and outer layers may be simultaneously broken. Each of the wires181of the conductor82has the conductive portion181aand the coated layer181badhered to the conductive portion181a. The coated layer181band the intermediate layer183are also adhered together. The intermediate layer183and the outer coated layer182are adhered together. Such joints have a strength of adhesion decreasing toward an outer side of the conductor82. In other words, the strength of adhesion between the conductive portion181aand the coated layer181bis lower than that between the coated layer181band the intermediate layer183and between the intermediate layer183and the outer coated layers182. The strength of adhesion between the coated layer181band the intermediate layer183may be higher than or identical with that between the intermediate layer183and the outer coated layers182. Usually, the strength of adhesion between, for example, two coated layers may be measured as a function of a tensile strength required to peel the coated layers away from each other. The strength of adhesion of the conductor82is selected in the above way to minimize the risk that the inner and outer layers may be broken together arising from a temperature difference between inside and outside the conductor82when heated or cooled. Usually, the heat generation or temperature change in the rotating electrical machine results in copper losses arising from heat from the conductive portion181aof the wire181and from an iron core. These two types of loss result from the heat transmitted from the conductive portion181ain the conductor82or from outside the conductor82. The intermediate layer183does not have a heat source. The intermediate layer183has the strength of adhesion serving as a cushion for the coated layer181band the outer coated layer182, thereby eliminating the risk that the coated layer181band the outer coated layer182may be simultaneously broken. This enables the rotating electrical machine to be used in conditions, such as in vehicles, wherein a resistance to high pressure is required, or the temperature greatly changes. In addition, the wire181may be made of enamel wire with a layer (i.e., the coated layer181b) coated with resin, such as PA, PI or PAI. Similarly, the outer coated layer182outside the wire181is preferably made of PA, PI, and PAI and has a large thickness. This minimizes a risk of breakage of the outer coated layer182caused by a difference in linear expansion coefficient. Instead of use of PA, PI, PAI to make the outer coated layer182having a large thickness, material, such as PPS, PEEK, fluorine, polycarbonate, silicon, epoxy, polyethylene naphthalate, or LCP which has a dielectric permittivity lower than that of PI or PAI is preferably used to increase the conductor density of the rotating electrical machine. The use of such resin enhances the insulating ability of the outer coated layer182even when it has a thickness smaller than or equal to that of the coated layer181band increases the occupancy of the conductive portion. Usually, the above resin has the degree of electric permittivity higher than that of an insulating layer of enamel wire. Of course, there is an example where the state of formation or additive results in a decrease in electric permittivity thereof. Usually, PPS and PEEK is higher in linear expansion coefficient than an enamel-coated layer, but lower than another type of resin and thus is useful only for the outer of the two layers. The strength of adhesion of the two types of coated layers arranged outside the wire181(i.e., the intermediate insulating layer and the outer insulating layer) to the enamel coated layer of the wire181is preferably lower than that between the copper wire and the enamel coated layer of the wire181, thereby minimizing a risk that the enamel coated layer and the above two types of coated layers are simultaneously broken. In a case where the stator is equipped with a water cooling mechanism, a liquid cooling mechanism, or an air cooling mechanism, thermal stress or impact stress is thought of as being exerted first on the outer coated layers182. The thermal stress or the impact stress is decreased by partially bonding the insulating layer of the wire181and the above two types of coated layers together even if the insulation layer is made of resin different from those of the above two types of coated layers. In other words, the above described insulating structure may be created by placing a wire (i.e., an enamel wire) and an air gap and also arranging fluorine, polycarbonate, silicone, epoxy, polyethylene naphthalate, or LCP. In this case, adhesive which is made from epoxy, low in electric permittivity, and also low in linear expansion coefficient is preferably used to bond the outer coated layer and the inner coated layer together. This eliminates breakage of the coated layers caused by friction arising from vibration of the conductive portion or breakage of the outer coated layer due to the difference in linear expansion coefficient as well as the mechanical strength. The outermost layer which serves to ensure the mechanical strength or securement of the conductor82having the above structure is preferably made from resin material, such as epoxy, PPS, PEEK, or LCP which is easy to shape and similar in dielectric constant or linear expansion coefficient to the enamel coated layer, typically in a final process for a stator winding. Typically, the resin potting is made using urethane or silicon. Such resin, however, has a linear expansion coefficient approximately twice that of other types of resin, thus leading to a risk that thermal stress is generated when the resin is subjected to the resin potting, so that it is sheared. The above resin is, therefore, unsuitable for use where requirements for insulation are severe and 60V or more. The final insulation process to make the outermost layer using injection moulding techniques with epoxy, PPS, PEEK, or LCP satisfies the above requirements. Other modifications will be listed below. The distance DM between a surface of the magnet unit42which faces the armature and the axial center of the rotor in the radial direction may be selected to be 50 mm or more. For instance, the distance DM, as illustrated inFIG.4, between the radial inner surface of the magnet unit42(i.e., the first and second magnets91and92) and the center of the axis of the rotor40may be selected to be 50 mm or more. The small-sized slot-less structure of the rotating electrical machine whose output is several tens or hundreds watt is known which is used for models. The inventors of this application have not seen examples where the slot-less structure is used with large-sized industrial rotating electrical machines whose output is more than 10 kW. The inventors have studied the reason for this. Modern major rotating electrical machines are categorized into four main types: a brush motor, a squirrel-cage induction motor, a permanent magnet synchronous motor, a reluctance motor. Brush motors are supplied with exciting current using brushes. Large-sized brush motors, therefore, have an increased size of brushes, thereby resulting in complex maintenance thereof. With the remarkable development of semiconductor technology, brushless motors, such as induction motors, have been used instead. In the field of small-sized motors, a large number of coreless motors have also come on the market in terms of low inertia or economic efficiency. Squirrel-cage induction motors operate on the principle that a magnetic field produced by a primary stator winding is received by a secondary stator core to deliver induced current to bracket-type conductors, thereby creating magnetic reaction field to generate torque. In terms of small-size and high-efficiency of the motors, it is inadvisable that the stator and the rotor be designed not to have iron cores. Reluctance motors are motors designed to use a change in reluctance in an iron core. It is, thus, inadvisable that the iron core be omitted in principle. In recent years, permanent magnet synchronous motors have used an IPM (Interior Permanent Magnet) rotor. Especially, most large-sized motors use an IPM rotor unless there are special circumstances. IPM motors has properties of producing both magnet torque and reluctance torque. The ratio between the magnet torque and the reluctance torque is timely controlled using an inverter. For these reasons, the IMP motors are thought of as being compact and excellent in ability to be controlled. According to analysis by the inventors, torque on the surface of a rotor producing the magnet torque and the reluctance torque is expressed inFIG.53as a function of the distance DM between the surface of the magnet unit which faces the armature and the center of the axis of the rotor, that is, the radius of a stator core of a typical inner rotor indicated on the horizontal axis. The potential of the magnet torque, as can be seen in the following equation (eq1), depends upon the strength of magnetic field created by a permanent magnet, while the potential of the reluctance torque, as can be seen in the following equation (eq2), depends upon the degree of inductance, especially, on the q-axis. The magnet torque=k·Ψ·Iq(eq 1) The reluctance torque=k·(Lq−Ld)·Iq·Id(eq2) Comparison between the strength of magnetic field produced by the permanent magnet and the degree of inductance of a winding using the distance DM shows that the strength of magnetic field created by the permanent magnet, that is, the amount of magnetic flux Ψ is proportional to a total area of a surface of the permanent magnet which faces the stator. In case of a cylindrical stator, such a total area is a cylindrical surface area of the permanent magnet. Technically speaking, the permanent magnet has an N-pole and an S-pole, the amount of magnetic flux Ψ is proportional to half the cylindrical surface area. The cylindrical surface area is proportional to the radius of the cylindrical surface and the length of the cylindrical surface. When the length of the cylindrical surface is constant, the cylindrical surface area is proportional to the radius of the cylindrical surface. The inductance Lq of the winding depends upon the shape of the iron core, but its sensitivity is low and rather proportional to the square of the number of turns of the stator winding, so that it is strongly dependent upon the number of the turns. The inductance L is expressed by a relation of L=μ·N{circumflex over ( )}2×S/δ where p is permeability of a magnetic circuit, N is the number of turns, S is a sectional area of the magnetic circuit, and δ is an effective length of the magnetic circuit. The number of turns of the winding depends upon the size of space occupied by the winding. In the case of a cylindrical motor, the number of turns, therefore, depends upon the size of space occupied by the winding of the stator, in other words, areas of slots in the stator. The slot is, as demonstrated inFIG.54, rectangular, so that the area of the slot is proportional to the product of a and b where a is the width of the slot in the circumferential direction, and b is the length of the slot in the radial direction. The width of the slot in the circumferential direction becomes large with an increase in diameter of the cylinder, so that the width is proportional to the diameter of the cylinder. The length of the slot in the radial direction is proportional to the diameter of the cylinder. The area of the slot is, therefore, proportional to the square of the diameter of the cylinder. It is apparent from the above equation (eq2) that the reluctance torque is proportional to the square of current in the stator. The performance of the rotating electrical machine, therefore, depends upon how much current is enabled to flow in the rotating electrical machine, that is, depends upon the areas of the slots in the stator. The reluctance is, therefore, proportional to the square of the diameter of the cylinder for a cylinder of constant length. Based on this fact, a relation of the magnetic torque and the reluctance torque with the distance DM is shown by plots inFIG.53. The magnet torque is, as shown inFIG.53, increased linearly as a function of the distance DM, while the reluctance torque is increased in the form of a quadratic function as a function of the distance DM.FIG.53shows that when the distance DM is small, the magnetic torque is dominant, while the reluctance torque becomes dominant with an increase in diameter of the stator core. The inventors of this application have arrived at the conclusion that an intersection of lines expressing the magnetic torque and the reluctance torque inFIG.53lies near 50 mm that is the radius of the stator core. It seems that it is difficult for a motor whose output is 10 kW and whose stator core has a radius much larger than 50 mm to omit the stator core because the use of the reluctance torque is now mainstream. This is one of reasons why the slot-less structure is not used in large-sized motors. The rotating electrical machine using an iron core in the stator always faces a problem associated with the magnetic saturation of the iron core. Particularly, radial gap type rotating electrical machines has a longitudinal section of the rotating shaft which is of a fan shape for each magnetic pole, so that the further inside the rotating electrical machine, the smaller the width of a magnetic circuit, so that inner dimensions of teeth forming slots in the core become a factor of the limit of performance of the rotating electrical machine. Even if a high performance permanent magnet is used, generation of magnetic saturation in the permanent magnet will lead to a difficulty in producing a required degree of performance of the permanent magnet. It is necessary to design the permanent magnet to have an increased inner diameter in order to eliminate a risk of generation of the magnetic saturation, which results in an increase size of the rotating electrical machine. For instance, a typical rotating electrical machine with a distributed three-phase winding is designed so that three to six teeth serve to produce a flow of magnetic flux for each magnetic pole, but encounters a risk that the magnetic flux may concentrate on a leading one of the teeth in the circumferential direction, thereby causing the magnetic flux not to flow uniformly in the three to six teeth. For instance, the flow of magnetic flux concentrates on one or two of the teeth, so that the one or two of the teeth in which the magnetic saturation is occurring will move in the circumferential direction with rotation of the rotor, which may lead to a factor causing the slot ripple. For the above reasons, it is required to omit the teeth in the slot-less structure of the rotating electrical machine whose distance DM is 50 mm or more to eliminate the risk of generation of the magnetic saturation. The omission of the teeth, however, results in an increase in magnetic resistance in magnetic circuits of the rotor and the stator, thereby decreasing torque produced by the rotating electrical machine. The reason for such an increase in magnetic resistance is that there is, for example, a large air gap between the rotor and the stator. The slot-less structure of the rotating electrical machine whose distance DM is 50 mm or more, therefore, has room for improvement for increasing the output torque. There are numerous beneficial advantages to use the above torque-increasing structure in the slot-less structure of rotating electrical machines whose distance DM is 50 mm or more. Not only the outer rotor type rotating electrical machines, but also the inner rotor type rotating electrical machines are preferably designed to have the distance DM of 50 mm or more between the surface of the magnet unit which faces the armature and the center of the axis of the rotor in the radial direction. The stator winding51of the rotating electrical machine10may be designed to have only the single straight section83of the conductor82arranged in the radial direction. Alternatively, a plurality of straight sections83, for example, three, four, five, or six straight sections83may be stacked on each other in the radial direction. For example, the structure illustrated inFIG.2has the rotating shaft11extending outside the ends of length of the rotating electrical machine10, but however, may alternatively be designed to have the rotating shaft11protruding outside only one of the ends of the rotating electrical machine10. In this case, it is advisable that a portion of the rotating shaft11which is retained by the bearing unit20in the cantilever form be located on one of the ends of the rotating electrical machine, and that the rotating shaft11protrude outside such an end of the rotating electrical machine. This structure has the rotating shaft11not protruding inside the inverter unit60, thus enabling a wide inner space of the inverter unit60, i.e., the cylinder71to be used. The above structure of the rotating electrical machine10uses non-conductive grease in the bearings21and22, but however, may alternatively be designed to have conductive grease in the bearings21and22. For instance, conductive grease containing metallic particles or carbon particles may be used. A bearing or bearings may be mounted on only one or both axial ends of the rotor40for retaining the rotating shaft11to be rotatable. For example, the structure ofFIG.1may have a bearing or bearings mounted on only one side or opposite sides of the inverter unit60in the axial direction. The magnet holder41of the rotor40of the rotating electrical machine10has the intermediate portion45equipped with the inner shoulder49aand the annular outer shoulder49b, however, the magnet holder41may alternatively be designed to have the flat intermediate portion45without the shoulders49aand49b. The conductor body82aof each of the conductors82of the stator winding51of the rotating electrical machine10is made of a collection of the wires86, however, may alternatively be formed using a square conductor having a rectangular cross section. The conductor82may alternatively be made using a circular conductor having a circular cross section or an oval cross section. The rotating electrical machine10has the inverter unit60arranged radially inside the stator50, but however, may alternatively be designed not to have the inverter60disposed inside the stator50. This enables the stator50to have a radial inner void space in which parts other than the inverter unit60may be mounted. The rotating electrical machine10may be designed not to have the housing30. In this case, the rotor40or the stator50may be retained by a wheel or another part of a vehicle. While this disclosure has been discussed in terms of the preferred embodiments in order to facilitate better understanding thereof, it should be appreciated that the invention can be embodied in various ways without departing from the principle of the invention. Therefore, this disclosure should be understood to include all possible embodiments and modifications to the shown embodiments which can be embodied without departing from the principle of this disclosure as set forth in the appended claims. | 209,761 |
11863024 | In the following, similar or identical elements are provided with the same reference signs. DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION FIG.1shows the drive device1in an exploded view. The drive device1is composed of a stator unit10, a rotor unit30, a base plate50and at least one printed circuit board60,60′. The base plate50substantially has a keyhole shape having a round portion54and a rectangular portion55. The base plate50comprises a thermally conductive material. The stator unit10and the rotor unit30are substantially annular. The stator unit10has at least three coils11. The coils11are formed from coil cores12and coil bobbins13. The coil cores12are pushed into the coil bobbins13in an axial direction A. For this purpose, the coil bobbins13have recesses17that extend in the axial direction A. The coil cores12have a shape that tapers inwards in a radial direction R. The coils11are arranged substantially in an annular shape and form a receiving space14in the stator unit10. The coil cores12stand on the base plate50or lie flat against the base plate50. The receiving space14is concentric with respect to the round portion54of the base plate50as seen in the radial direction R. The coil cores12are connected via projections15and form at least one coil core element16. In this embodiment, the coil core element16is designed as an annular closed ring and has an annular recess in the region of the receiving space14. Coil wires are wound around the circumference of the coil bobbins13. The coil bobbins13are at least in part arranged on the printed circuit board60,60′. The printed circuit board60,60′ is arranged on the base body50or lies flat on said base body50. The printed circuit board60,60′ has a recess61in the region of the receiving space14, which is formed by the coils11of the stator unit10. The coil cores12protrude through the printed circuit board60,60′ in the region of the recess61. The printed circuit board60,60′ has an open-loop and/or closed-loop control circuit62. This open-loop and/or closed-loop control circuit62is formed by one or more electronic components that are electrically connected to one another by conductor paths introduced into the printed circuit board60,60′. The open-loop and/or closed-loop control circuit62is used to control and/or regulate the drive device1. In this case, the open-loop and/or closed-loop control circuit62is arranged substantially on a plane with the coil bobbins13. The open-loop and/or closed-loop control circuit62is substantially arranged on the side of the printed circuit board60,60′ opposite the base plate50. The coil bobbins13project at least in part beyond the recess61of the printed circuit board60,60′. The coil bobbins13are arranged on the side of the printed circuit board60,60′ opposite the base plate50, as seen from the base plate50. The coil bobbins13lie flat on the printed circuit board60,60′. The printed circuit board60,60′ rests in the base plate50. For this purpose, the base plate50has a recess51, the circumference of which extends substantially in parallel with the outer circumference56of the base plate50. The printed circuit board60,60′ has a contour63corresponding to the recess51. In the region in which the coil core element16or the coil cores12lie, the recess51has an annular depression52that substantially corresponds to the outer circumference of the coil core element16. In an assembled state of the drive device1, the coil core element16is pushed with the coil cores12into the coil bobbins13such that the coils11are formed by the coil cores12of the coil core element16and the coil bobbins13. This results in an arrangement in which the coil bobbins13are at least in part arranged above the coil core element16. The rotor unit30has a bearing unit31. The rotor unit30is rotatably supported with respect to the base plate50by means of this bearing unit31. Part of the bearing unit31is connected to the base plate50in a non-rotatable manner. Another part of the bearing unit31is rotatable with respect to the base plate50. The bearing unit31stands on the base plate50or lies flat against the base plate50. The rotor unit30is inserted into the stator unit10in the axial direction A. The rotor unit30is arranged concentrically with respect to the coils11in an axial direction A. Here, the rotor unit30protrudes with its bearing unit31into the receiving space14of the stator unit10. The rotor unit30has a bearing unit31having a support element32and a bearing bolt35. The bearing bolt35of the bearing unit31has a shaft part37and a contact flange38. The contact flange38is in contact with the base plate50and stands centrally in the round portion54of the base plate50. In this central region of the round portion54of the base plate50, the annular depression52has an annular recess53that encloses the contact flange38around the circumference thereof. The bearing bolt35stands on the base plate50in a non-rotatable manner and is connected to the base plate50by means of a fastening means, such as a screw. When viewed from the base plate50, the shaft part37of the bearing bolt35lies above the annular recess53. The top of the annular recess53is substantially in a plane with the top of the printed circuit board60,60′ such that the coil bobbins13rest on the one hand on the printed circuit board60,60′ and also on the top of the annular recess53. The support element32of the bearing unit31has a contact region33that extends in a radial direction R. The contact region33is located on the side of the coils11opposite the base plate50and extends over the coils11. The contact region33is spaced apart from the coils11and is not in contact with the coils11. Permanent magnets34are arranged on the support element32of the bearing unit31and in particular on the contact region33, which extends radially to the coils11. Said permanent magnets34rest at least in part in the support element32or on the support element32. In case of resting of the permanent magnets34, the support element32has corresponding recesses for this purpose. The permanent magnets34have a conical shape that tapers radially inwards. A gap S is formed in the axial direction A between the contact region33or the permanent magnets34and the coils11. At least one ball bearing36is arranged between the bearing bolt35and the support element32. The support element35has a flange portion39extending in the axial direction A. When viewed in the radial direction R, the ball bearings36are arranged between the shaft part37of the bearing bolt35and the flange portion39of the support element32. In this way, the support element32is decoupled from the bearing bolt35. FIG.2is a sectional view through a further embodiment of the drive device1, the open-loop and/or closed-loop control circuit62being arranged on a further printed circuit board60′ and the coil bobbins13being arranged on the printed circuit board60that is separate from the further printed circuit board60′. In the embodiment according toFIG.1, a one-piece printed circuit board60is provided for the open-loon and/or closed-loop control circuit62and for the coils11or coil bobbins13. The further printed circuit board60′ rests in the part of the recess51of the base plate50that is in the rectangular portion55of the base plate50. The printed circuit board60rests in that part of the recess51of the base plate50that is in the round portion54of the base plate50. Otherwise, the embodiment of the drive device1shown inFIG.2corresponds to the embodiment shown inFIG.1. The coil core element16is located in the recess51of the base plate50. The coil cores12extend away from the base plate50in the axial direction A. The bearing bolt35rests with its contact flange38in the annular depression52in the central region of the round portion54of the base plate50. InFIG.2it can be seen very clearly that the part of the flange portion38of the bearing bolt35opposite the base plate50, the sides of the projections15opposite the base plate50, and the side of the printed circuit board60opposite the base plate50lie on a plane together with the top of the annular recess53. The coil bobbins13stand on the top of the printed circuit board60, the top of the projections15and the top of the annular recess53. Furthermore, it can be seen very clearly inFIG.2that, when viewed from the inside in the radial direction R, the shaft part37of the bearing bolt35is surrounded by the ball bearings36. The ball bearings36are in turn surrounded by the flange portion39of the support element. The bearing bolt35is screwed to the base plate50by a fastening means, in this case a screw, and is thus fixed in a non-rotatable manner. The support element32is decoupled from the base plate50by the ball bearings36, as a result of which the bearing unit31or the rotor unit30may be rotated. In addition, it can be clearly seen inFIG.2that the permanent magnets34are arranged in a part of the support element32extending in the radial direction R. The permanent magnets34are arranged substantially in parallel with the base plate50, the printed circuit board60, the projections15, and the top of the coil bobbins13or the coils11. A gap S is arranged between the top of the coils11, i.e. the side of the coils11that faces away from the base plate50, and the permanent magnet34or the support element32. Similarly, an annular gap RS is arranged between the coils11and the flange portion39of the support element32in the radial direction R. As a result, the rigid stator unit10connected to the base plate50is completely rotationally decoupled from the rotor unit30, which is rotatable in the circumferential direction. InFIG.2, the assembly of the drive device can also be seen in the region of the rotor unit30and the stator unit10. The coil cores12are connected to the coil core element16by the projections15. This coil core element16rests in the base body50. The top of the projections15and the top of the printed circuit board60lie substantially on a plane with the top of the annular recess53, which cannot be seen inFIG.3. The coil bobbins13stand on this plane between the printed circuit board60, projections15and the annular recess53. Furthermore,FIG.2shows the support element32with the permanent magnets34at least in part resting therein. The permanent magnets34are substantially parallel to the plane of the printed circuit board60or the projections15. The support element32or the rotor device30is rotatable in its circumferential direction and is rotationally decoupled from the base plate50by means of the bearing bolt35, which is connected non-rotatably to the base plate50, and the ball bearings36. In all embodiments, the printed circuit board60,60′, the coils11and the base plate50may be potted with a potting compound70(not shown in the drawings). The potting compound70has a high thermal conductivity. An embodiment of the spin window100is shown inFIGS.3and4. FIG.3is a sectional view of the spin window100having the drive unit1according to one of the embodiments described above.FIG.4is an exploded view of the spin window100according to one of the embodiments described above. With regard to the spin window100described below, reference is made toFIG.4. A pane110is arranged on the rotor unit30of the drive unit1. The pane110is substantially circular. The pane110is held on the rotor unit30between a connecting plate111and a cover cap112, the connecting plate111and the cover cap112being connected to the rotor unit30, in particular to the support element32of the rotor unit. An annular seal113is arranged between the cover cap112and the pane110. The pane110is made of a transparent material, for example a transparent plastics material or glass, laminated safety glass or tempered safety glass in particular being suitable as glass. The pane110may also be constructed in two layers. For example, the pane110has a support on the side facing away from the base plate50. The support may, for example, be a layer of a scratch- and impact-resistant transparent ceramic. The support may in particular be connected to the pane110by means of a bonding layer. A lamination layer, with which the support is laminated onto the pane110, comes into consideration as the bonding layer. Alternatively, the pane110can be coated on the side facing away from the base plate50with a coating that is, for example, scratch and impact resistant. The pane110has a circumferential collar115on its outer circumference114located in the radial direction R. The collar115has a radially circumferential guide groove116projecting in the axial direction A that engages with a guide projection121of an annular base body120of the spin window100. The guide groove116has no contact with the guide projection of the base body. The connecting plate111is L-shaped in cross section. The short side of the L-shaped cross section surrounds the coils11in the axial direction A with respect to the printed circuit board60,60′. The connecting plate111is arranged with the long side of the L-shaped cross section between the support element32and the pane110or between the support element32and the cover cap112. The connecting plate is therefore adjacent both to the cover cap112and to the pane110in the axial direction A. When viewed in a radial direction R, the connecting plate111rests on the inside of a contact recess40of the support element32and is arranged in the radial direction R between said contact recess40of the support element32and the pane110. This results in the connecting plate111being stepped in the axial direction A in the region of the contact between the pane110and the printed circuit board60,60′. The cover cap112has a diameter that corresponds at least to the diameter of the rotor unit30or the stator unit10. In an outer region of the radius of the cover cap112, a continuous annular groove running in the circumferential direction is provided in which the annular seal113rests. The cover cap112rests on the pane110. The cover cap112and the pane110are arranged concentrically with respect to the rotor unit30and the stator unit10. The pane110is clamped between the cover cap112and the connecting plate or the support element. The base plate50of the drive device1is arranged on the inner diameter122of an annular base body120and projects radially inward into the annular base body120. For the base plate50of the drive device1, a cover housing130protruding towards the annular base body120is provided, the rotor unit30of the drive device1at least in part protruding through the cover housing130. The annular base body120has a passage123for a lead80of the drive device1. A cover housing130protrudes in the axial direction into the short portion of the L-shaped connecting plate111. A seal131is arranged between the base plate50and the cover housing130. The cover housing130encloses the printed circuit board60,60′ and the stator unit10at least in part on the side facing away from the base plate50. In addition, the printed circuit board60,60′ and the open-loop and/or closed-loop control circuits62arranged thereon and the elements of the stator unit10may be encapsulated with the potting compound70. The invention is not restricted to one of the embodiments described above, but may be modified in many ways. All of the features and advantages arising from the claims, the description and the drawing, including structural details, spatial arrangements and method steps, may be essential to the invention both individually and in a wide variety of combinations5.1Drive device10Stator unit11Coils12Coil cores13Coil bobbins14Receiving space15Projections16Coil core element17Recess30Rotor unit31Bearing unit32Support element33Contact region34Permanent magnets35Bearing bolt36Ball bearing37Shaft part38Contact flange39Flange portion40Contact recess50Base plate51Recess52Annular depression53Annular recess54Round portion55Rectangular portion56Outer circumference60Printed circuit board61Recess62Open-loop and/or closed-loop control circuit63Contour60Further printer circuit board70Potting compound80Lead100Spin window110Pane111Connecting plate112Cover cap113Annular seal114Circumference115Collar116Guide groove120Base body121Guide projection122Inner diameter123Passage130Cover housing131SealA Axial directionR Radial directionS GapRS Annular gap | 16,269 |
11863025 | DESCRIPTION OF EMBODIMENTS The following describes embodiments of the present disclosure with reference to attached drawings. In the attached drawings, identical or similar components are expressed by identical or similar reference signs. In the explanation of the respective embodiments, overlapping description with regard to the identical or similar components may be omitted. Characteristics and features described in each of the embodiments are applicable to the other embodiments so far as they are not incompatible with each other. First Embodiment FIG.1is a sectional view illustrating the schematic structure of a canned motor pump110that is provided with a resin molded rotor10A according to a first embodiment. As illustrated, the canned motor pump110is configured to include a canned motor30provided with a stator14fixed to an inner circumferential surface of a motor frame13by shrink fit or the like and with the resin molded rotor10A placed rotatably in the stator14; and an impeller1mounted to and fixed to a leading end part of a main shaft7of the canned motor30. The stator14is configured to include a stator core15configured by stacking magnetic plate materials with holes in a circular shape formed at respective centers thereof to form inside thereof a through-space having an inner circumference in an approximately cylindrical shape; and an electric conductor (coil) wound on the stator core15. A stator can18in an approximately cylindrical shape made of stainless steel or the like is fixed to the inner circumferential surface of the stator core15. The stator can18separates a rotor10(the resin molded rotor10A) from the stator14. More specifically, the stator can18divides the inside of the motor frame13into a rotor chamber where the rotor10(the resin molded rotor10A) is placed and a stator chamber where the stator14is placed. The resin molded rotor10A includes the rotor10, the main shaft7which the rotor10is mounted to, and a resin mold11provided to integrally cover the rotor10and part of the main shaft7. The rotor10includes a rotor core12and a permanent magnet9embedded inside of the rotor core12. The resin mold11covers an outer circumferential surface and end faces of the rotor core12on respective shaft end sides to grooves7-1on a load side and on an opposite load side that are portions where grooves are formed in outer circumferences of respective shaft end sides of the main shaft7outside of a mounting range of the rotor core12. There is a uniform clearance6between the inner circumference of the stator can18and the surface of the resin mold11formed on the outer circumference of the rotor core12. This embodiment illustrates an application example of an IPM (Internal Permanent Magnet) motor having the permanent magnet9placed inside of the rotor10. Other application examples include an SPM (Surface Permanent Magnet) motor having a permanent magnet placed on the surface of the rotor10and a motor having an electromagnet placed in a rotor. An end18-2on the opposite load side (on a left side inFIG.1) of the stator can18is brought into contact with the motor frame13and is fixed to the motor frame13by welding respective abutting portions thereof. An end18-1on the load side (on a right side inFIG.1) of the stator can18is inserted into a through hole of a stator can lateral plate19on the load side, where the through hole is formed at the center of a disk-shaped plate material provided as the stator can lateral plate19, and is fixed to the stator can lateral plate19on the load side by welding respective abutting portions thereof from an end face side. The motor frame13is formed in a bottomed cylindrical shape having an opposite load side end closed by a bearing bracket4on the opposite load side and an open load side end. The bearing bracket4is provided with a cylindrical protrusion4athat is protruded in a cylindrical shape inward along an axial direction of the main shaft7, and the cylindrical protrusion4ais provided with a bearing6on the opposite load side that supports the main shaft7to be freely rotatable. A cut is formed in part of the cylindrical protrusion4ato allow for a flow of a pump handling liquid. A sealing member20-3configured by, for example, an O-ring made of rubber or the like, is placed between the motor frame13and the bearing bracket4to seal between the motor frame13and the bearing bracket4and prevent leakage of the pump handling liquid to outside. The bearing bracket4is fixed to the motor frame13by tightening a bolt22. Furthermore, a thrust disk8-2on the opposite load side is fixed to the main shaft7and is placed between the bearing6and the rotor10. A bearing bracket3on the load side is, on the other hand, placed at the load side end of the motor frame13. A bearing5on the load side is placed on an output side of the main shaft7(on the right side inFIG.1) to rotatably support the main shaft7and is fixed to this bearing bracket3. Furthermore, a thrust disk8-1on the load side is fixed to the main shaft7and is placed between the bearing5and the rotor10. A space is formed between the motor frame13and the bearing bracket3. The stator can lateral plate19is configured to have an outer circumferential part placed between and fixed by the motor frame13and the bearing bracket3by inserting the outer circumferential part of the stator can lateral plate19into this space and tightening a bolt21for fixing a pump casing2. Furthermore, the bearing bracket3is configured to have an outer circumferential part placed between and fixed by the motor frame13and the pump casing2. A sealing member20-2configured by, for example, an O-ring made of rubber or the like, is placed between the bearing bracket3and the stator can lateral plate19to seal between the bearing bracket3and the stator can lateral plate19. A sealing member20-1configured by, for example, an O-ring made of rubber or the like, is placed between the bearing bracket3and the pump casing2to seal between the bearing bracket3and the pump casing2. The configuration of respectively placing the sealing member20-2between the stator can lateral plate19and the bearing bracket3and placing the sealing member20-1between the bearing bracket3and the pump casing2prevents leakage of the pump handling liquid to outside. FIG.2is diagrams illustrating the general configuration of the resin molded rotor10A with the resin mold11formed therein.FIG.2(a)is a sectional front view, andFIG.2(b)is a left side view.FIG.3is a partial enlarged sectional view illustrating the resin molded rotor10A. The resin molded rotor10A is configured by covering the outer circumferential surface of the rotor10having the rotor core12with the permanent magnet9embedded therein and regions up to the grooves7-1provided in the outer circumferences of the respective shaft end sides of the main shaft7outside of the mounting range of the rotor10, with the resin mold11. A material having high corrosion resistance (for example, a PPS material or a fluororesin PFA) is used for the resin mold11. Setting the thickness of a resin film of the resin mold11corresponding to a rotor can to about 0.5 mm to 1.0 mm is expected to improve the mechanical strength, the corrosion resistance and the liquid resistance. Using an excessive amount of the material is likely to cause problems from different views, for example, reduction of the economic performance and the increased likelihood in shape change caused by, for example, “sink” of the material. It is accordingly required to set the thickness of the resin film, such as to prevent the occurrence of such problems. It is also suitable to set the thicknesses of respective shaft end side portions11-1and11-2of the resin mold11to about 2 to 3 mm by taking into account the positioning accuracy in the axial direction. These thicknesses are determined by taking into account, for example, the dimensional tolerance of the positioning accuracy in the axial direction of the rotor core12in the case of mounting the rotor core12to the main shaft7, in addition to the specification dimension with regard to the thickness of the resin film of the resin mold11corresponding to the rotor can in relation to the mechanical strength, the corrosion resistance and the liquid resistance. The respective grooves7-1are annular grooves provided to go round the outer circumferential surface of the main shaft7in a circular direction at positions coming into contact with the load side end and the opposite load side end (end faces) of the rotor10(positions where the rotor10overlaps with the grooves7-1). The grooves7-1are formed to have any sectional shape having such dimensions and shape as to hold an O-ring26, for example, a triangular shape like a right triangle shown inFIGS.1-3, a rectangular shape (shown inFIG.8(a)), a wedge shape (shown inFIG.8(b)) or a beveled groove shape (shown inFIG.8(c)). According to the embodiment, the O-ring26is placed in each of the grooves7-1. The O-ring26is made of rubber and is configured to favorably and closely adhere to the rotor10, the main shaft7and the resin mold11and to have such elasticity as to deform favorably following thermal deformations of these members. The O-ring26is preferably made of rubber having heat resistance such as fluororubber (for example, FKM or FFKM) by taking into account the heat resistance in a resin molding process of molding with PPS or the like at high temperature. The O-ring26is mounted in each of the grooves7-1in an annular shape and is subsequently molded integrally with the rotor10and the main shaft7by using the resin mold11to closely adhere to and to be fixed to the rotor10, the main shaft7and the resin mold11. The O-ring26is placed in each of the grooves7-1. This configuration suppresses/prevents the position of the O-ring26from being displaced by the pressure of the resin in the course of resin molding. According to the embodiment, the O-rings26are placed in the respective grooves7-1to closely adhere to the respective shaft end-side end faces of the rotor10, the main shaft7and the resin mold11. This configuration enhances the adhesion between the resin mold11and the main shaft7and also enhances the sealing property between the resin mold11and the main shaft7and the sealing property between the resin mold11and the rotor10. As a result, this configuration more reliably suppresses or prevents the rotor10from being exposed to or coming into contact with the pump handling liquid and/or a corrosive gas. Furthermore, according to the embodiment, the grooves7-1and the O-rings26are placed at the positions coming into contact with the respective shaft end-side end faces of the rotor10. This configuration reduces the distance of the resin mold11in the axial direction and enhances the adhesion between the resin mold11and the main shaft7. Moreover, the configuration that the grooves7-1and the O-rings26are placed at the positions coming into contact with the respective shaft end-side end faces of the rotor10reduces the required length in the axial direction of the resin mold11and saves the amount of the molding agent (for example, a resin) used. The resin molded rotor10A may be manufactured by, for example, a manufacturing process described below: (a) inserting the rotor core12into the main shaft7with the grooves7-1formed thereon; (b) placing the O-rings26in the grooves7-1of the main shaft7; (c) guiding the rotor core12by the main shaft7and positioning the rotor core12in an injection molding die; (d) mounting the permanent magnet9to the rotor core12(the permanent magnet9may be mounted to the rotor core12prior to insertion of the rotor core12into the main shaft7); (e) molding the rotor core12, the permanent magnet9and the O-ring26with a resin material (injection molding) not to cause exposure of the rotor core12, the permanent magnet9or the O-ring26. This obtains the resin molded rotor10A having the rotor10, the main shaft7and the resin mold11. (f) inserting the obtained resin molded rotor10A into a magnetizing yoke to be magnetized. The resin mold11formed by injecting a molten resin material has a larger linear expansion coefficient than those of the rotor core12and the main shaft7made of metal materials and is shrunk toward an outer diameter side of the rotor core12relative to the rotor core12in a natural cooling process after the injection molding. Accordingly, a shrinking force toward the rotor side and toward the outer diameter side is likely to be applied to a region of the resin mold11that closely adheres to the main shaft7and to decrease the sealing property between the resin mold11and the main shaft7. In the resin molded rotor10A of this embodiment, the resin mold11injection-molded in the die has the larger linear expansion coefficient than those of the rotor core12and the main shaft7made of the metal materials. Even when the resin mold11is shrunk in the natural cooling process after injection, the O-rings26are deformed following the shrinkage of the resin mold11such as not to make a clearance between the resin mold11and the main shaft7. This maintains the sealing property between the resin mold11and the main shaft7. Furthermore, the O-rings26are portions protruded from the outer circumferential surface of the main shaft7. This configuration also has the advantageous effect of utilizing shrinkage of the resin mold11to cause the resin mold11to closely adhere to the O-rings26. According to the embodiment, the configuration of not using a metal material such as stainless steel material as the rotor can material but of resin-molding the canned motor with a resin material having high corrosion resistance achieves the original purpose or more specifically protection of the rotor core and the magnet material from corrosion. This configuration is not only inexpensive but prevents generation of eddy current, which is generated in a can made of a metal material during operation, thereby providing an efficient canned motor. In the resin molded rotor10A of the embodiment, the sealing structure of the rotor10is implemented by the resin mold11and the O-rings26. This has the advantageous effects of the simple manufacturing process and the high assembling performance. The following describes the operations of the canned motor pump110shown inFIG.1. A rotating magnetic field generated by connecting a three-phase AC power source with an outlet line17and supplying three-phase alternating current to an electric conductor (coil)16of the stator14is applied to the rotor10to rotate the impeller1fixed to the main shaft7of the rotor10. The pump handling liquid sucked in through a suction port2aof the pump casing2by the rotation of the impeller1flows into the pump casing2, passes through a discharge volute24, and is discharged from a discharge port (not shown), while part of the pump handling liquid passes through a hole3aprovided in the bearing bracket3on the load side and flows into a rotor chamber surrounded by the stator can18. The pump handling liquid flowing into the rotor chamber passes through the clearance δ between the resin mold11and the stator can18, flows into the cylindrical protrusion4ain a bottomed cylindrical shape of the bearing bracket4on the opposite load side, passes through a through hole7aprovided at the center of the main shaft7, flows into the impeller1, and joins up with the sucked pump handling liquid. As described above, the pump handling liquid flows into the rotor chamber surrounded by the stator can18and flows through the clearance δ between the resin molded rotor10A and the stator can18. The embodiment is configured to integrally seal the rotor10and the main shaft7with the resin mold11, to provide the grooves7-1in the vicinity of interfaces between the main shaft7and the resin mold11and to place the O-rings26in the grooves7-1to enhance the sealing property at the interfaces between the resin mold11and the main shaft7. As a result, this configuration maintains the interfaces between the resin mold11and the main shaft7in a good sealing condition and suppresses or prevents the rotor10from being exposed to or coming into contact with the pump handling liquid. This extends the life of the resin mold rotor10A. Second Embodiment FIG.4is a diagram illustrating an example of the partial schematic structure of a resin molded rotor according to a second embodiment. This embodiment has a resin molded rotor10A of a different configuration from that of the embodiment described above but otherwise has a similar configuration to that of the embodiment described above. The following describes differences from the above embodiment with omitting description with regard to the similar configuration to that of the above embodiment. According to this embodiment, O-rings26are mounted after formation of a resin mold11for a rotor10and a main shaft7. In the resin molded rotor10A of this embodiment, the resin mold11is provided with annular protrusions11A on the respective shaft end sides of a rotor core12, i.e., on the load side and on the opposite load side, and O-ring grooves11B are formed between the annular protrusions11A and an outer circumferential surface of the main shaft7. The annular protrusions11A are provided to be protruded from the respective shaft end side portions11-1and11-2of the resin mold11outward in the axial direction relative to the rotor10and to go round the main shaft7in the circumferential direction. The annular protrusions11A of the resin mold11are formed by injection molding of a resin into a die having portions in shapes corresponding to the protrusions. For example, the rotor10mounted to the main shaft7is provided, and the resin mold11is formed by injection molding to cover the rotor10and the main shaft7and to have the annular protrusions11A. The O-rings26are subsequently fit in between the annular protrusions11A and the main shaft7to be placed, mounted, and fixed between the annular protrusions11A and the main shaft7. According to the embodiment, the O-ring26is placed to seal the interface between the resin mold11and the main shaft7. This suppress the interface between the resin mold11and the main shaft from being exposed to or coming into contact with the pump handling liquid and thereby suppresses the rotor core12from being exposed to or coming into contact with the pump handling liquid via the interface between the resin mold11and the main shaft7. Moreover, the configuration of placing the O-ring26after formation of the resin mold11prevents a positional shift of the O-ring26in the injection molding process of the resin mold and prevents the O-ring26from being affected by the heat in the injection molding process. The foregoing describes the example where the annular protrusions11A are provided continuously along the whole circumference. The annular protrusions11A are, however, not necessarily provided along the whole circumference but may be provided discretely in the circumferential direction, as long as the annular protrusions11A serve to hold the O-rings26such as to seal interfaces between the resin mold11and the main shaft7. FIG.5is a diagram illustrating an example of the partial schematic structure of a resin molded rotor according to a modification of the second embodiment. As illustrated inFIG.5, grooves7-1(shown inFIGS.1to3) may be provided in the outer circumferential surface of the main shaft7corresponding to the annular protrusions11A, and O-rings26may be placed between the grooves7-1and the annular protrusions11A to be fixed in O-ring grooves11B. In this configuration, the distance between the annular protrusion11A and the outer circumference of the main shaft7(or the inner surface of the groove7-1), the depth and/or the shape of the groove7-1are set such as to cause the O-ring26to sufficiently seal between the main shaft7and the annular protrusion11A. In this configuration, the groove7-1in the outer circumferential surface of the main shaft7more reliably suppresses the O-ring26from being displaced in the axial direction during the motor operation. Other Embodiments (1) In the above embodiment, one O-ring is provided on each side in the axial direction of the rotor10. Two or more O-rings may, however, be provided on at least one side of the rotor10.FIG.6is a diagram illustrating an example of the partial schematic structure of a resin molded rotor10A according to another embodiment. InFIG.6, a plurality of grooves7-1are provided in the outer circumferential surface of the main shaft7on at least one side out of the respective shaft end sides of the rotor10, and O-rings26are placed in the respective grooves7-1. This configuration enables the interfaces between the resin mold11and the main shaft7to be sealed by the plurality of O-rings26and further enhances the sealing property. (2) No O-ring may be placed in at least one groove out of a plurality of grooves, and the resin mold11may enter this at least one groove (as shown inFIG.7).FIG.7is a diagram illustrating an example of the partial schematic structure of a resin molded rotor10A according to another embodiment. InFIG.7, a groove7-1represents a groove where an O-ring26is placed, whereas a groove7-2represents a groove where no O-ring26is placed. In this illustrated example, the grooves7-1and7-2are provided in the outer circumferential surface of the main shaft7, and the O-ring26is placed in the groove7-1but is not placed in the groove7-2. This configuration enables the resin mold11to closely adhere to a side face of the groove7-2by taking advantage of a difference between a linear expansion coefficient of the resin mold11and a linear expansion coefficient of a material used to form the rotor10. This configuration further enhances the sealing property between the main shaft7and the resin mold11by combining the sealing by means of the O-ring26placed in the groove7-1with the sealing by means of adhesion of the resin into the groove7-2. The sectional shape of the groove7-2where no O-ring26is placed is preferably a shape that enhances the adhesion of the resin mold11and may be any of various shapes including those illustrated inFIGS.1to3andFIG.8. The number of the groove7-1where the O-ring26is placed and the number of the groove7-2where no O-ring26is placed may be one or plural. The groove7-2where no O-ring26is placed but the resin mold11enters may be provided on a side nearer to the rotor10and/or on a side farther away from the rotor10than the groove7-1where the O-ring26is placed. (3) Different O-ring placing structures described above may be employed for at least one O-ring and for another or other O-rings. An identical O-ring placing structure may be employed for the respective shaft end sides of the rotor10, or different O-ring placing structures may be employed for the respective shaft end sides of the rotor10. An identical O-ring placing structure may be employed for all two or more O-rings on at least one side of the rotor10, or different O-ring placing structures may be employed for at least part of two or more O-rings on at least one side in the axial direction of the rotor10. These O-ring placing structures may be employed in combination with grooves where no O-rings are placed. (4) The foregoing describes the canned motor pump that handles the liquid as one example. The canned motor provided with the resin molded rotor10A described above may, however, be applied to a canned motor pump that handles a liquid and/or a gas. Third Embodiment FIG.9is a diagram illustrating the schematic configuration of a vacuum pump apparatus according to this embodiment.FIG.10is a diagram illustrating the schematic configuration of a fan scrubber. The vacuum pump apparatus of this embodiment may be used as one of manufacturing equipment for semiconductors, liquid crystals, solar panels, LEDs or the like. This embodiment describes an example where the resin molded rotor10A and/or the canned motor30described above is applied to the vacuum pump apparatus. The vacuum pump apparatus100of this embodiment includes a vacuum pump120connected with a non-illustrated processing chamber to suck a gas from the processing chamber (evacuate the processing chamber), a fan scrubber200connected with and subsequent to the vacuum pump120, and a detoxification device140connected with the fan scrubber200. One usable example of the vacuum pump120is a dry vacuum pump. The vacuum pump120may be, for example, a canned motor pump provided with the canned motor30including the resin molded rotor10A described above. The fan scrubber200is provided to remove foreign substances such as solidified substances (for example, reaction byproducts) included in the gas from the vacuum pump120. Furthermore, the detoxification device140is provided to detoxify the gas from the vacuum pump120. The detoxification device140used may be one or plural devices selected among a combustion type, a dry type, a wet type, a heater type, a fluorine fixation type, a catalyst type, a plasma type, a dilution unit type (a blower, addition of N2, and addition of the air), and the like. In the vacuum pump apparatus100of the embodiment, the gas sucked in vacuum by the vacuum pump120is first guided to the fan scrubber200to pass through the fan scrubber200and is then guided to the detoxification device140. This configuration suppresses foreign substances such as solidified substances from being introduced into the detoxification device140and thereby suppresses clogging of the detoxification device140or reduction in the processing efficiency of the detoxification device140. The liquid (waste liquid) used to trap the foreign substances in the fan scrubber200may be introduced into the detoxification device140to be reused in the detoxification device140as shown by a hatched part inFIG.9. (Fan Scrubber) As shown inFIG.10, the fan scrubber200includes a casing220, a fan240, a liquid discharge portion260, and a canned motor30. A main shaft7and a rotor10of the canned motor30are covered with a resin mold11(omitted from the illustration ofFIG.10) to have the similar configuration to that of the resin molded rotor10A described above. The configuration of the fan scrubber200described herein is only one example, and the resin molded rotor and/or the canned motor described above may be employed for a motor of a fan scrubber of any configuration. In the fan scrubber200illustrated herein, the main shaft7is linked with a fan240to provide a turning driving force to the fan240. The canned motor30includes the main shaft7, the rotor10, a stator14, a motor frame13, and a stator can18. Like the embodiment described above, the rotor10, together with part of the main shaft7, is covered with a resin mold (as shown by the resin mold11inFIG.1). The rotor10, the main shaft7, and the resin mold11constitute the resin molded rotor10A. In this canned motor30, the rotor10and the main shaft7are rotated by electromagnetic induction through supply of electricity to the coil of the stator14. In the fan scrubber200of this embodiment, the gas discharged from the vacuum pump120is taken in from a gas intake port220a.The fan scrubber200removes foreign substances such as solidified substances included in the intake gas and supplies the processed gas from a gas discharge port220bto the detoxification device140. The gas intake port220aserving to guide the gas from the vacuum pump120to the fan240in the casing220, the gas discharge port220bserving to discharge the intake gas, and a liquid discharge outlet220cserving to discharge a cleaning solution as waste liquid are formed in the casing220. The fan240is placed inside of the casing220. The fan240is mounted to the main shaft7of the canned motor30and is rotated by the power from the canned motor30to stir inside of the casing220. In one example, the fan240may be configured to include two disk-shaped lateral plates opposed to each other and a plurality of blades fixed between these lateral plates. The liquid discharge portion260is provided inside of the casing220. The liquid discharge portion260serves to jet the cleaning solution inside of the casing220. One available example of the cleaning solution is water. Using an alkaline liquid including a hydroxylation system (for example, sodium hydroxide or potassium hydroxide) liquid as the cleaning solution enhances the trapping efficiency of foreign substances and also suppresses corrosion of the casing220, the fan240and the like. The cleaning solution may be determined, based on the foreign substances to be trapped. The liquid discharge portion260includes a nozzle270having a plurality of jetting ports formed therein and a liquid supply pipe280arranged to communicate with the nozzle270. InFIG.10, a thick line arrow indicates a pathway of the cleaning solution discharged from the nozzle270. The liquid discharge portion260supplies the cleaning solution to the nozzle270via the liquid supply pipe280by means of a non-illustrated pressure-feed mechanism and discharges the cleaning solution from the nozzle270. According to this embodiment, the nozzle270is provided to be opposed to a rotating shaft of the fan240(the main shaft7of the canned motor30) inside of the fan240to discharge the cleaning solution from a center part of the fan240to an outer periphery thereof. A collision plate230is formed between the fan240and the gas discharge port220bin the casing220. The cleaning solution jetted from the nozzle270is splashed to an outer periphery of the nozzle270by the centrifugal force of the fan240. Providing the collision plate230suppresses the cleaning solution from entering the gas discharge port220b.The collision plate230may be formed not to cover only between the fan240and the gas discharge port220but to cover the approximately entire circumference of the fan240. In the canned motor30, the stator can18serves to separate the rotor10from the stator14. More specifically, the stator can18divides inside of the motor frame13into a rotor chamber48where the rotor10is placed and a stator chamber49where the stator14is placed. Like the clearance δ shown inFIG.1, the stator can18is applied to an inner face of the stator14(or more specifically, a stator core thereof) with a slight gap formed between the stator18and the rotor10. Frame lateral plates (stator can lateral plates)19-1and19-2are fit between the motor frame13and the stator can18on respective ends of the canned motor30in an axial line AL direction. The motor frame13, the stator can18, and the frame lateral plates19-1and19-2work to seal the stator chamber49. The frame lateral plates19-1and19-2are fastened to brackets3and4on respective end sides of the canned motor30. The rotor chamber48is defined by the stator can18and the brackets3and4. The bracket3on the load side is linked with the casing220. The bracket3is provided with a through hole formed to cause the main shaft7to be inserted through and is also provided with a bearing5in this through hole, which is a slide bearing to support the main shaft7. The bracket4on the opposite load side is provided with a bearing6that is a slide bearing to support the main shaft7. The bracket4is also provided with a liquid inlet4aformed to cause the bearing6to communicate with outside. This liquid inlet4ais connected with a non-illustrated pressure-feed mechanism to supply the cleaning solution into the rotor chamber. As shown by a thick one-dot chain line inFIG.10, when the cleaning solution is supplied through the liquid inlet4ato the bearing6on the opposite load side by the non-illustrated pressure-feed mechanism, the cleaning solution passes through between the bearing6and the main shaft7and moves into the rotor chamber48. The cleaning solution subsequently passes through between the resin molded rotor10A (the rotor10) and the stator can18in the rotor chamber48and goes toward the bearing5on the load side. The cleaning solution then passes through between the bearing5and the main shaft7(through a liquid outlet) and is discharged into the casing220. In this fan scrubber200, the resin molded rotor10A of the canned motor30has a similar configuration to that of the embodiment described above and has similar functions and advantageous effects to those of the embodiment described above. More specifically, in the resin molded rotor10A an O-ring26is placed between the resin mold11and the main shaft7. Compared with the prior art configuration, this configuration more reliably maintains the sealing property at an interface between the resin mold11and the main shaft7and more reliably suppresses the rotor core and the permanent magnet from being exposed to or coming into contact with the liquid. At least the following aspects are provided from the embodiments described above. According to a first aspect, there is provided a resin molded rotor, comprising: a rotor configured to hold a magnet; a main shaft provided with the rotor mounted thereto and configured to transmit power to outside; and a resin mold configured to integrally cover the rotor and part of the main shaft on respective sides in an axial direction of the rotor, wherein an O-ring is placed between the resin mold and the main shaft to seal between the resin mold and the main shaft. In the resin molded rotor of this aspect, the configuration of sealing an interface between the resin mold and the main shaft by means of the O-ring enhances the sealing property of the rotor by the resin mold. The O-ring made of rubber has high adhesion to the main shaft and the resin mold and is capable of following thermal deformation of the resin mold. Accordingly, even when the resin mold is shrunk relative to the rotor and the main shaft due to a difference of linear expansion coefficient, the O-ring is deformed following thermal deformation of the resin, so as not to form a clearance between the resin mold and the main shaft but to maintain adhesion to the resin mold and the main shaft. As a result, this configuration enhances the sealing property between the main shaft and the resin mold. Even when the rotor, the main shaft and/or the resin mold are thermally deformed during operation of the motor, the O-ring is deformed following thermal deformations of these members, so as not to form a clearance between the resin mold and the main shaft but to maintain adhesion to the resin mold and the main shaft. As a result, this configuration enhances the sealing property between the main shaft and the resin mold. According to a second aspect, in the resin molded rotor of the first aspect, a groove may be formed in part of an outer circumferential surface of the main shaft covered with the resin mold, and the O-ring may be placed in the groove to seal between the resin mold and the main shaft. In the resin molded rotor of this aspect, the configuration of placing the O-ring in the groove provided in the main shaft suppresses/ prevents the O-ring from being shifted from a desired position in the process of injection molding the resin and provides a stable sealing structure. According to a third aspect, in the resin molded rotor of the second aspect, the O-ring may closely adhere to an end face of the rotor. In the resin molded rotor of this aspect, the O-ring closely adheres to the main shaft and the resin mold, and no resin mold is present on the outer circumferential surface of the main shaft between the end face of the rotor and the O-ring. This configuration enhances the sealing property between the resin mold and the main shaft. This configuration also reduces a distance where the resin is present in a main shaft axial direction. This enhances the sealing property between the resin mold and the main shaft and also reduces the amount of the resin used. According to a fourth aspect, in the resin molded rotor of either the second aspect or the third aspect, part of the groove may be arranged to overlap with the rotor in the axial direction. This configuration reliably enables the O-ring to closely adhere to and to be fixed to the end face of the rotor. According to a fifth aspect, in the resin molded rotor of any one of the second aspect to the fourth aspect, a plurality of the grooves may be provided in part of the outer circumferential surface of the main shaft covered with the resin mold, and the O-ring may be placed in each of all the grooves. In the resin molded rotor of this aspect, the plurality of O-rings further enhance the sealing property between the main shaft and the resin mold. According to a sixth aspect, in the resin molded rotor of any one of the second aspect to the fourth aspect, a plurality of the grooves may be provided, and the O-ring may not be placed in part of the grooves. This configuration enables the resin mold to closely adhere to a side face of the groove where the O-ring is not placed by taking advantage of a difference between a linear expansion coefficient of the resin mold and a linear expansion coefficient of a material used to form the rotor. As a result, the combination of sealing by the O-ring with sealing by adhesion of the resin to the groove further enhances the sealing property between the main shaft and the resin mold. According to a seventh aspect, in the resin molded rotor of the first aspect, the resin mold may be molded such as to form, together with the main shaft, an O-ring groove, and the O-ring may be placed in the O-ring groove. This configuration enables the O-ring to be placed in the O-ring groove after molding of the resin mold. This configuration accordingly prevents a positional shift of the O-ring in the injection molding process of the resin mold and also prevents the O-ring from being affected by heat in the injection molding process. According to an eighth aspect, the resin molded rotor of the seventh aspect may further comprise a protrusion that is protruded from an axial direction end face of the resin mold, and the O-ring groove may be formed between the protrusion and an outer circumferential surface of the main shaft. In the resin molded rotor of this aspect, the O-ring groove is formed by the protrusion of the resin mold. This configuration has no necessity of forming thick the entire axial direction ends of the resin mold and thereby reduces the amount of the resin used. Furthermore, the configuration of suppressing the entire axial direction ends of the resin mold from being thickened suppresses/ prevents reduction of the sealing property of the resin mold to the rotor end face and suppresses/ prevents “sink” of the resin mold. According to a ninth aspect, in the resin molded rotor of the eighth aspect, a groove may be provided in the outer circumferential surface of the main shaft at a position opposed to the protrusion, and the O-ring may be placed between the protrusion and the groove. In the resin molded rotor of this aspect, the groove provided in the outer circumferential surface of the main shaft further more reliably suppresses displacement of the O-ring in the axial direction during operation of the motor. According to a tenth aspect, in the resin molded rotor of any one of the first aspect to the ninth aspect, the O-ring may be provided on respective sides in the axial direction of the rotor. This configuration enhances the sealing property at interfaces between the resin mold and the main shaft on both sides in the axial direction of the rotor where the interfaces between the resin mold and the main shaft are present. According to an eleventh aspect, there is provided a canned motor, comprising: the resin molded rotor of any one of the first aspect to the tenth aspect; a bearing configured to rotate and support the main shaft of the resin molded rotor; and a stator of a canned structure configured to surround the resin molded rotor and to cause a rotating magnetic field to be applied to the rotor of the resin molded rotor. This aspect configures the canned motor by using the resin molded rotor described above and thereby provides a long-life canned motor by the simple configuration at low cost. According to a twelfth aspect, there is provided a canned motor pump, comprising: the canned motor of the eleventh aspect; an impeller fixed to the main shaft; and a pump casing configured to surround the impeller. The canned motor pump may be configured to suck/discharge a liquid and/or a gas. This aspect configures the canned motor pump by using the resin molded rotor described above and thereby provides a long-life canned motor pump by the simple configuration at low cost. According to a thirteenth aspect, there is provided a fan scrubber, comprising: the canned motor of the eleventh aspect; a fan connected with the main shaft of the canned motor; a casing provided with a gas intake port and a gas discharge port and configured to place the fan therein; and a nozzle configured to jet a liquid in the casing. This aspect configures the fan scrubber by using the resin molded rotor described above and thereby provides a long-life fan scrubber by the simple configuration at low cost. According to a fourteenth aspect, there is provided a vacuum pump apparatus, comprising: the fan scrubber of the thirteenth aspect; and a vacuum pump configured to suck a gas in vacuum from a vacuum chamber and to discharge a gas to the gas intake port of the fan scrubber. This aspect configures the vacuum pump apparatus by using the fan scrubber that employs the resin molded rotor described above and thereby provides a long-life vacuum pump apparatus by the simple configuration at low cost. Although the embodiments of the present invention have been described based on some examples, the embodiments of the invention described above are presented to facilitate understanding of the present invention, and do not limit the present invention. The present invention can be altered and improved without departing from the subject matter of the present invention, and it is needless to say that the present invention includes equivalents thereof. In addition, it is possible to arbitrarily combine or omit respective constituent elements described in the claims and the specification in a range where at least a part of the above-mentioned problem can be solved or a range where at least a part of the effect is exhibited. The present application claims priority to Japanese patent application No. 2020-110723 filed on Jun. 26, 2020. The entire disclosure of Japanese patent application No. 2020-110723 filed on Jun. 26, 2020, including the specification, claims, drawings and abstract is incorporated herein by reference in its entirety. The entire disclosure of Japanese Unexamined Patent Publication No. H07-312852 (Patent Document 1), Japanese Patent No. 5602615 (Patent Document 2), Japanese Patent No. 6298237 (Patent Document 3), and Japanese Patent No. 6461733 (Patent Document 4), including the specification, claims, drawings and abstract is incorporated herein by reference in its entirety. REFERENCE SIGNS LIST 1impeller2pump casing3bracket4bracket5bearing6bearing7main shaft7athrough hole7-1groove7-2groove8-1thrust disk8-2thrust disk9permanent magnet10rotor10A resin molded rotor11resin mold11A annular protrusion11B O-ring groove12rotor core13motor frame14stator15stator core16electric conductor (coil)17outlet line18stator can19stator can lateral plate19-1,19-2frame lateral plates (stator can lateral plates)20-1sealing member20-2sealing member20-3sealing member21bolt22bolt23blade lock nut24discharge volute26O-ring30canned motor100vacuum pump apparatus110canned motor pump120vacuum pump140detoxification device200fan scrubber220casing220agas intake port220bgas discharge port220cliquid discharge outlet230collision plate240fan260liquid discharge portion270nozzle280liquid supply pipe | 43,728 |
11863026 | With reference toFIG.1, an aircraft1is shown. The aircraft is of conventional configuration, having a fuselage2, wings3, tail4and a pair of propulsion systems5. One of the propulsion systems5is shown in figure detail inFIG.2. FIG.2shows the propulsion system5schematically. The propulsion system5includes an internal combustion engine in the form of a gas turbine engine10. The gas turbine engine10comprises, in axial flow series, a propulsor in the form of a fan/propeller12, a compressor14, combustion equipment16and high and low-pressure turbines18,20. The gas turbine engine10works in the conventional manner so that air is accelerated by the fan12to produce two air flows: a first core air flow into the compressor14and a second air flow which bypasses the compressor14to provide propulsive thrust. The core air flows through the compressor14where it is compressed, before delivering that air to the combustion equipment16, where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the turbines18,20before being exhausted through a nozzle to provide additional propulsive thrust. The high18and low-pressure turbines18,20drive respectively the compressor14and fan12, each by suitable interconnecting shaft22,24. Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. By way of example such engines may have an alternative number of interconnecting shafts (e.g. three) and/or an alternative number of compressors and/or turbines. Further, the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan. The propulsion system5further comprises one or more electrical machines. In particular, the system5comprises an electric motor28. The motor28is of a conventional type, such as a permanent magnet electric machine, and is configured to drive a propulsor such as the fan12. In the present embodiment, the motor28is coupled to the fan12via the low-pressure shaft24. In this embodiment, the electric motor28is of a “core shaft mounted” type, in which a rotor29of the motor28is mounted directly to a surface of the low-pressure shaft24, and is surrounded by a stator50, provided radially outwardly of the rotor29. The stator comprises electrical windings (not shown), which can be energised to produce a rotating magnetic field. This rotating magnetic field interacts with a magnetic field of the rotor29, to cause rotation when acting as a motor. Consequently, the fan12may be powered by either or both of the gas turbine engine10via the low-pressure turbine20, and the motor28. The electric motor28is coupled to an energy storage device30in the form of one or more of a chemical battery, fuel cell, and capacitor, which provides the electric motor28with electrical power during operation. In some cases, multiple energy storage systems, which may be of different types (chemical battery, fuel cell etc) may be provided for each propulsion system5. In other cases, a common energy storage device30may be provided for multiple propulsion systems. The propulsion system optionally comprises one or more further electric machines such as a generator32, which is coupled to one or both of the motor28and the energy storage device30, such that additional electrical energy can be provided in operation. The generator32is typically driven by the low-pressure shaft24of the gas turbine engine10. The generator32may be coupled to the shaft24via a gearbox and/or clutch to allow for selectively connecting and disconnecting the generator32from the shaft24. In some cases, the motor28may act as a generator. Details of the electric motor28are shown inFIG.3. As will be appreciated, the generator32is broadly similar to the motor28. The motor28comprises a rotor29and a stator50. The rotor29comprises a shaft40which defines a rotational axis X. The shaft40is typically constructed from a structural material such as steel, aluminium or titanium, and is configured to be rotated by the motor28in use, and is coupled to the propulsor12. Radially outward of the shaft is a plurality of steel laminations42. The steel laminations are typically thin, to minimise eddy currents, to thereby reduce losses and heat generation. Radially outward of the laminations42is a plurality of permanent magnets44. The permanent magnets44are provided on a circumferential outer surface of the laminations42, and so the rotor can be said to be of the “surface permanent magnet” type. The permanent magnets44are typically adhered to the steel laminations by an adhesive. In order to maintain the rotor in position in use, in opposition to centrifugal loads on the rotor, the rotor further comprises a rotor sleeve46which is provided radially outward of and at least partly surrounding the permanent magnets44. The rotor sleeve46is described in further detail below, and is shown in more detail inFIGS.4and5. Radially outward of the sleeve46is an air gap48, which allows for relative rotation between the rotor and stator50. The stator50is provided radially outward of the air-gap48and comprises a plurality of stator coils (not shown), which, when energised, drive the rotor by interaction between the magnetic fields of the stator coils and the permanent magnets44. Referring now toFIG.4, the rotor sleeve46is shown in more detail. The sleeve comprises an inner layer52and outer layer54which comprise different materials. The inner layer52comprises a composite material comprising filaments56of a first material having a relatively low modulus of elasticity. That is to say, the first material is relatively elastic, and can deform to a relatively large degree when a tensile force is applied. The material of the first filaments must also be relatively flexible, to allow it to be wound into shape. Examples of suitable materials include glass fibres (e.g. E-glass or S-glass), aramid, Polybenzoxazole (PBO), nylon, or Dynema, or a mixture of one of more of these materials. In one example, in the case of glass fibres, the fibres have a stiffness modulus of approximately 90 Giga-Pascals GPa. The fibres56of the inner layer52are embedded within a matrix material such a resin such as phenolic, epoxy, cyanate ester resin or PEEK58. Together, the fibres56and resin58form a composite material. The matrix material in which the fibres are situated have an elastic modulus of approximately 8 GPa. For a volume fraction of 50%, this gives an overall elastic modulus of the low elastic modulus filament layer of approximately 50 GPa. Similarly, the outer layer54comprises a composite material comprising filaments60in a matrix material62. However, the filaments60are of a second material having a relatively high modulus of elasticity, i.e. higher than the modulus of elasticity than the first material. In this embodiment, the filaments60comprise carbon fibre, though other fibre materials may be suitable. The matrix material62may be the same as the matrix material58of the inner layer52, or may be a different material to ensure compatibility with the different fibres materials. In one example, the filaments comprise a stiffness modulus of approximately 320 (GPa). The carbon fibre filaments are embedded within a matrix, with a volume fraction of approximately 65%. The matrix typically has an elastic modulus of approximately 8 GPa. This gives an overall elastic modulus for the carbon fibre composite layer of approximately 213 GPa. Consequently, the filaments of the outer layer have a modulus of elasticity approximately 3 to 4 times higher than the filaments of the inner layer. In other embodiments, the filaments of the inner layer may a stiffness closer to that of the outer layer. The ratio of outer layer fibre stiffness to inner fibre layer stiffness may be in the range of 2:1 to 40:1. Though the drawings are not shown to scale, particular dimensions are illustrated inFIGS.4and5. The thickness T1of the inner layer in the radial direction is approximately 0.5 mm, and more generally is between 0.1 and 1 mm. On the other hand, the thickness T2of the outer layer is generally between 3 and 15 mm, depending on the required strength and stiffness of the sleeve46. Typically, in order to optimise the properties of the inner and outer layers52,54the filaments56,60are arranged in plies, such that they are wound in predetermined directions. The plies of the first layer52are provided as a plurality of sublayers, with the plies of each sub-layer being angled relative to a neighbouring layer. This ensures interlocking of the sub-layers, and enhances the multi-directional strength of the inner layer52. The filaments56of the inner layer52are arranged approximately ±45° relative to the rotational axis X of the rotor29(i.e. filaments56lie approximately +45° angles and −45° angles). In some cases, rather than distinct sublayers, the plies of the first layer52may be interwoven, with filaments provided at alternating ±45° angles. In some cases, the filaments may be provided at between ±30° and ±60°. The filaments60of the outer layer54are arranged 90° to the rotational axis X for reasons that will be explained below. The filaments56,60of both the inner and outer layers52,54are subject to a pre-stress during layup and, which is held in place once the composite structure is cured, or the pre-stress may be applied after curing. Typically, the pre-stress is between 500 and 1500 Mega Pascals (MPa), and in one embodiment tested by the inventors, is approximately 1,100 MPA. Such a high pre-stress ensures a radial compressive load on the rotor magnets in order to secure their contact with the rotor in response to centrifugal forces in operational use, and is higher than can typically be achieved in the prior art. This contributes to a reduction in overall thickness of the sleeve46compared to prior art composite or metallic sleeves. Several methods may be used for construction of the sleeve. One method is to apply the filaments56,60directly to the permanent magnets44, while applying tension to the filaments. The filaments could be pre-impregnated with matrix material (e.g. resin), or applied as sheets. Once applied, the composite material is then cured. In either case, the filaments56of the first layer52will be applied first until the required thickness is built up, followed by the second layer54. However, a problem with this process is that the matrix material typically requires a high temperature to cure. On the other hand, if the curing process must be undertaken at a temperature below the Curie temperature of the permanent magnets44, otherwise magnetisation of the magnets will be lost. Consequently, the sleeve must be built up slowly and cured in multiple stages, resulting in a time consuming and slow process. This method also tends to lead to reduced pre-stress, since the pre-stress decreases during the curing step. The pre-stress using this installation method has been found to be limited to around 500-800 MPa in practice. A second method is illustrating inFIG.7, which utilises an apparatus shown inFIG.7. In a first step, the filaments56,60are wrapped around a separate mandrel (not shown), and cured. This may be conducted using pre-impregnated fibres that are directly placed on the mandrel or dry fibres that are drawn through a resin bath and then placed on a mandrel in what is known as a wet filament winding process. In a second step, the structure is cured on the mandrel. Since the mandrel does not need to maintain magnetisation, the curing process can take place at a higher temperature. In a third step, the sleeve is optionally cut into smaller rings, and forced over a conical assembly tool64, shown inFIG.8. The assembly tool64has an outside diameter which tapers outwardly from a smaller diameter to a larger diameter which matches or slightly exceeds the outer diameter of the permanent magnets46of the rotor29. By forcing the sleeve46over the mandrel, a pre-tension is applied, which increases the radially inward force applied by the sleeve46to the permanent magnets44when installed. In a fourth step, the sleeve46is forced onto the permanent magnets44, until the sleeve46is fully installed in the desired position. At this point, the sleeve46is fully installed on the rotor29, with an interference fit. This installation method with high level of pre-stress has previously been tried by the inventors with conventional composite sleeves, but has been unsuccessful. In those cases, the composite sleeve was damaged by the installation process, leading to breakage of the fibres. By providing an inner layer52having a lower modulus of elasticity, the high modulus fibres are protected from mechanical damage during the press-fitting process, and so the sleeve can be more readily stretched over the assembly tool, without damaging the fibres of the second layer54. The disclosed sleeve and assembly method has been found by the inventors to provide a rotor sleeve having increased strength and reduced thickness relative to prior arrangements, in view of the increased pre-tension that can be applied. In one example, the radial thickness of the sleeve was reduced from 10.2 mm to 8.4 mm. It will be appreciated that, as well as resulting in a direct reduction in weight, the reduced thickness also reduces the effective size of the airgap between the rotor29and stator50. This in turn increases the transmission of torque between the rotor and stator, and so increases power density. In one electric machine to which the sleeve has been applied by the inventors, this has resulted in an overall weight reduction of 77 kg for a 2.5 megawatt (MV) electric machine. It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein. The electric machine may be used for other applications. For example, the electric machine may be utilised as a starter/generator for a gas turbine engine. Alternatively, the electric machine may be used as either a generator or a motor in any other suitable application, such as an electric airliner that does not include a gas turbine engine. | 14,493 |
11863027 | DETAILED DESCRIPTION FIG.1shows a simplified structure of a cross-section of a rotating electrical machine, such as a motor. The machine ofFIG.1comprises a machine frame11to which a stator12of the machine is attached. A rotor13is arranged inside the stator12and a shaft14is attached to the rotor. The rotor is supported in the frame with bearings15which are arranged between the shaft and the machine frame. The frame of an electrical machine is typically grounded. When an electrical machine is fed with a frequency converter or with a similar device, common mode voltage is formed between the stator of the machine and grounded frame. In the simplified structure ofFIG.1it is shown that the stator of the machine is capacitively coupled to the rotor of the machine. The capacitance between the two is shown to be as Cair. Further, another capacitance Cbearis shown between the machine frame and the shaft. As the common mode voltage is formed between the stator and the ground, the formed capacitances from the stator to the rotor Cairand from the rotor shaft to the frame Cbearare effectively coupled in series. It is known that in a series connection of capacitances that the charge is evenly distributed among the capacitors. This further leads to the fact that voltages in series connection of capacitors are inversely proportional to the capacitance. Thus, if the bearing capacitance Cbearis small compared to the stator rotor capacitance Cair, then most of the common mode voltage is effective across the bearing. In the present invention a rotating electrical machine comprises a machine frame, a rotor, a shaft attached to the rotor, and bearings supporting the shaft and the rotor in the machine frame. Further, the rotating electrical machine comprises an electrically conducting member16having a hole, the member being attached to the machine frame such that the shaft extends through the hole. The cross-sectional view ofFIG.1shows an embodiment in which the electrically conducting member16is attached to the machine frame and the shaft of the electrical machine extends through the hole. The electrically conducting member is preferably a metal plate, which is made of one piece of metal. The metal plate is attached to the machine frame such that they are galvanically coupled. When a metal plate is attached as described, a capacitive coupling is formed between the shaft and the machine frame. InFIG.1this is depicted as capacitance Cring. The capacitance Cringis effectively in parallel with the bearing capacitance Cbear. This is further illustrated inFIG.2in which a simplified circuit diagram is shown. When capacitances Cringand Cbearare connected in parallel, the effective capacitance value is increased. As the stator to rotor capacitance Cairstays the same, the increased capacitance leads to decreased voltage Vbearover the bearings due to the common mode voltage. As mentioned above, the electrically conducting member is preferably a one-piece metal plate which is machined so that a hole is formed in the plate. The dimension of the hole in the electrically conducting member correspond preferably to the outer diameter of the shaft. When attached to the frame, the electrically conducting member is preferably in mechanical contact with the shaft. That is, the hole is comparatively tight with respect to the shaft. Once attached to the frame and when the electrical machine is operated, the shaft of the machine rotates in the hole and makes the hole in the electrically conducting member larger. The hole in the electrically conducting member enlarges to a certain diameter which is slightly larger than the diameter of the shaft. Thus, when installed, the electrically conducting member does not necessarily form a capacitive coupling with the shaft. When installed the coupling between the shaft and the electrically conducting member is galvanic. Once the shaft has rotated in the hole for a certain time, the diameter of the hole gets larger, and the galvanic connection is lost. It is known that the value of capacitance is inversely proportional to the difference between the capacitor plates, which correspond here to the shaft and the electrically conducting member. As the gap between the two is machined by the shaft to a minimal value, the effective capacitance has a maximal value. According to an embodiment, the electrically conducting member, such as a metal plate, is formed of multiple pieces. The formation of metal plate from multiple of pieces, such as two, may be preferred as a tight fitting with the shaft can be obtained without the need of inserting the shaft through the hole. When formed of multiple of pieces, the electrically conducting member can be constructed to form a hole. When installing, the pieces of the electrically conducting member are attached to each other and to the machine frame such that the shaft is situated in the hole formed of the separate pieces. The material of the electrically conducting member is preferably copper. Copper as a material is soft such that the shaft of the machine can wear the inner surface of the hole easily so that capacitive properties are obtained. The electrically conducting member may also be made of electrically conducting alloys. For example, the member may be epoxy having electrically conducting properties. The electrically conducting member of the disclosure comprises electrically conducting properties and is preferably of a material that is softer than the shaft. The electrically conducting member which may be a metallic member, such as a metal plate, is preferably attached to the machine frame by welding, soldering or with screws. It is to be understood, that purpose of attaching the plate to the machine frame is to obtain a galvanic connection between the machine frame and the member. In the method of the invention, a rotating electrical machine with a machine frame and a shaft is provided, and an electrically conducting member with a hole is provided, the diameter of the hole corresponding to the diameter of the shaft. Further in the method, the electrically conducting member is attached to the machine frame such that the shaft extends through the hole. In the method, the electrically conducting member is preferably a metal plate. Further, the electrically conducting member is preferably in mechanical contact with the shaft when installed. The mechanical contact also means that the shaft and the electrically conducting member are in galvanic contact. According to an embodiment, when the rotating electrical machine is operated to rotate the shaft, the hole is enlarged such that a galvanic connection is lost, and capacitive coupling is established. It should be understood, that in addition to the above-described capacitive couplings, other capacitive couplings are present in a rotating electrical machine. However, the above simplification and the capacitive couplings are presented for understanding the effect of the invention. It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims. | 7,268 |
11863028 | DETAILED DESCRIPTION Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present disclosure is not limited to some embodiments described herein but may be implemented in various different forms. One or more of the constituent elements in the embodiments may be selectively combined and substituted for use within the scope of the technical spirit of the present disclosure. In addition, unless otherwise specifically and explicitly defined and stated, the terms (including technical and scientific terms) used in the embodiments of the present disclosure may be construed as the meaning which may be commonly understood by the person with ordinary skill in the art to which the present disclosure pertains. The meanings of the commonly used terms such as the terms defined in dictionaries may be interpreted in consideration of the contextual meanings of the related technology. In addition, the terms used in the embodiments of the present disclosure are for explaining the embodiments, not for limiting the present disclosure. In the present specification, unless particularly stated otherwise, a singular form may also include a plural form. The expression “at least one (or one or more) of A, B, and C” may include one or more of all combinations that can be made by combining A, B, and C. In addition, the terms such as first, second, A, B, (a), and (b) may be used to describe constituent elements of the embodiments of the present disclosure. These terms are used only for the purpose of discriminating one constituent element from another constituent element, and the nature, the sequences, or the orders of the constituent elements are not limited by the terms. Further, when one constituent element is described as being ‘connected’, ‘coupled’, or ‘attached’ to another constituent element, one constituent element may be connected, coupled, or attached directly to another constituent element or connected, coupled, or attached to another constituent element through still another constituent element interposed therebetween. In addition, the expression “one constituent element is provided or disposed above (on) or below (under) another constituent element” includes not only a case in which the two constituent elements are in direct contact with each other, but also a case in which one or more other constituent elements are provided or disposed between the two constituent elements. The expression “above (on) or below (under)” may mean a downward direction as well as an upward direction based on one constituent element. Referring toFIGS.1to11, a busbar unit100for a motor according to an embodiment of the present disclosure includes terminals200, a holder300configured to support the terminals200and having an accommodation portion310provided in an outer surface of the holder300, and a temperature measurement module400provided in the accommodation portion310. For reference, the busbar unit100for a motor according to the embodiment of the present disclosure may be mounted in various types of motors in accordance with required conditions and design specifications, and the present disclosure is not restricted or limited by the types and structures of the motors. As an example, a motor, to which the busbar unit100according to the embodiment of the present disclosure is applied, may be used as a drive motor for an environmentally-friendly vehicle, such as a hybrid vehicle and/or an electric vehicle, which obtains driving power from electrical energy. For example, the drive motor is an inner-rotor-type synchronous motor and includes the stator10installed in a motor housing (not illustrated), and a rotor (not illustrated) rotatably installed in the stator10with a predetermined air gap from the stator10. The busbar unit100according to the embodiment of the present disclosure may be connected to the stator20. The stator10may be accommodated in the housing (not illustrated), and coils (not illustrated) may be wound around the stator10so as to induce an electrical interaction between the stator and the rotor. For example, the stator10includes a plurality of split cores (not illustrated) provided to cooperatively define a ring shape, and a support ring (not illustrated) provided to surround outer circumferential surfaces of the plurality of split cores. The split core may be variously changed in number and structure in accordance with required conditions and design specifications, and the present disclosure is not restricted or limited by the number of split cores and the structure of the split core. More specifically, the split core may be provided by stacking a plurality of electrical steel sheets in an axial direction of the rotor. A bobbin (not illustrated) (made of plastic, for example) is provided around each of the split cores, and the coil is wound around the bobbin. According to another embodiment of the present disclosure, the stator may include a single core. The rotor is provided to be rotated by the electrical interaction between the stator10and the rotor. As an example, the rotor may include a rotor core (not illustrated) and magnets (not illustrated). The rotor core may be structured by stacking a plurality of circular plates each provided in the form of a thin steel sheet or structured in the form of a bin. A hole (not illustrated), to which a shaft is coupled, may be provided at a center of the rotor. Protrusions (not illustrated), which guide the magnets, may protrude from an outer circumferential surface of the rotor core. The magnets may be attached to the outer circumferential surface of the rotor core so as to be spaced apart from one another at predetermined intervals in a circumferential direction of the rotor core. In addition, the rotor may include a can member (not illustrated) disposed to surround the magnets and configured to prevent the separation of the magnets. The busbar unit100includes the terminals200, the holder300, and the temperature measurement module400. The busbar unit100is disposed at an upper side of the stator10. The terminal200is provided to electrically connect the coil of the stator10to an external power source. The terminal200may be at least any one of phase terminals (a U-phase terminal, a V-phase terminal, and a W-phase terminal) connected to a U-phase power source, a V-phase power source, and a W-phase power source and a neutral terminal for electrically connecting the phase terminals. For example, the busbar unit100may include a total of four terminals200(the U-phase terminal, the V-phase terminal, the W-phase terminal, and the neutral terminal). More specifically, the terminal200includes a body (not illustrated) accommodated in the holder300, and a terminal portion (not illustrated) protruding from an inner circumferential surface of the body and connected to the coil. The body may be variously changed in structure and shape in accordance with required conditions and design specifications. For example, the body may have a single-layered structure and may be provided as a band member in the form of an arc (or a ring) having a predetermined curvature. According to another embodiment of the present disclosure, the body may have a double-layered structure (multilayer structure) having a bent portion. The terminal portion is provided on the inner circumferential surface of the body. An end of the coil of the stator10is connected to (e.g., fused with) the terminal portion. The terminal portion may have various structures to which the end of the coil may be connected, and the present disclosure is not restricted or limited by the structure and shape of the terminal portion. In addition, the terminal200may include a power terminal portion (not illustrated) protruding from an outer circumferential surface of the holder300. The power terminal portion extends from an outer surface of the body and protrudes from the outer circumferential surface of the holder300. The power terminal portion may be electrically connected to each of external power cables corresponding to the respective phases (the U-phase, the V-phase, and the W-phase). The holder300is provided to support the arrangement state of the terminals200and electrically insulate the terminals200. The holder300may be variously changed in material and shape in accordance with required conditions and design specifications, and the present disclosure is not restricted or limited by the material and shape of the holder300. For example, the holder300may have a hollow ring shape and be provided as a molded product (made of an insulating material, for example) provided by injection molding. The accommodation portion310is provided in the outer surface of the holder300, and the temperature measurement module400is mounted in the accommodation portion310. In this case, the outer surface of the holder300is defined as including both the upper surface and the outer circumferential surface of the holder300. Hereinafter, an example will be described in which the accommodation portion310is provided in the upper surface of the holder300and disposed in the axial direction of the motor. The accommodation portion310may have various structures in which the temperature measurement module400may be accommodated (or seated), and the present disclosure is not restricted or limited by the structure of the accommodation portion310. For example, the accommodation portion310may be recessed in the upper surface of the holder300. At least a part of the temperature measurement module400may be accommodated in the accommodation portion310. In particular, the accommodation portion310may have a shape corresponding to a shape of the temperature measurement module400. In the embodiment of the present disclosure illustrated and described above, the example has been described in which the accommodation portion310is recessed in the outer surface of the holder300. However, according to another embodiment of the present disclosure, the accommodation portion may have a structure protruding from the outer surface of the holder. The temperature measurement module400is provided in the accommodation portion310and serves to monitor a temperature of the motor (e.g., a temperature of the coil). The temperature measurement module400may have various structures capable of being accommodated in the accommodation portion310and monitoring the temperature of the motor. For example, the temperature measurement module400may include a temperature sensor410, and a sensor housing420provided to surround the temperature sensor410. A typical contact temperature sensor410(e.g., a thermocouple or a thermistor) may be used as the temperature sensor410, and the present disclosure is not restricted or limited by the type of temperature sensor410and the sensing methods. The sensor housing420is provided to surround the temperature sensor410to protect the temperature sensor410. The sensor housing420is accommodated in the accommodation portion310. In particular, the temperature sensor410is exposed from a bottom surface of the sensor housing420that faces a bottom surface310aof the accommodation portion310. The exposed surface of the temperature sensor410is in close contact with the bottom surface310aof the accommodation portion310in the state in which the sensor housing420is accommodated in the accommodation portion310. Since the temperature sensor410is in close contact with the bottom surface310aof the accommodation portion310as described above, the contact area between the temperature sensor410and the holder300may increase. Therefore, it is possible to obtain an advantageous effect of improving the temperature measurement accuracy of the temperature sensor410. More particularly, the bottom surface310aof the accommodation portion310is a flat surface, and the temperature sensor410is in surface contact with the bottom surface310a. According to another embodiment of the present disclosure, the bottom surface of the accommodation portion may be a curved surface. Referring toFIG.5, according to the exemplary embodiment of the present disclosure, an adhesive layer AL may be provided on the bottom surface310aof the accommodation portion310, and the temperature measurement module400may be attached to the adhesive layer AL. Since the adhesive layer AL is provided on the bottom surface310aof the accommodation portion310and the temperature measurement module400is attached to the adhesive layer AL as described above, it is possible to obtain an advantageous effect of stably maintaining the arrangement state of the temperature measurement module400. In particular, the adhesive layer AL is made of a thermally conductive bonding agent (e.g., epoxy bonding agent). Since the adhesive layer AL is made of a thermally conductive bonding agent as described above, it is possible to obtain an advantageous effect of minimizing deterioration in temperature detection performance of the temperature sensor410caused by the adhesive layer AL. According to another embodiment of the present disclosure, as illustrated inFIGS.6and7, a filling layer FL may be provided, instead of the adhesive layer AL, by filling a space between an inner surface of the accommodation portion310and the temperature measurement module400with a filling material (e.g., epoxy). The temperature measurement module400accommodated in the accommodation portion310may be integrally fixed to the filling layer FL by curing the filling layer FL. Referring toFIGS.8and9, according to the exemplary embodiment of the present disclosure, fixing holes320may be provided in the bottom surface310aof the accommodation portion310, and fixing protrusions430may be provided on the bottom surface of the sensor housing420that faces the bottom surface310aof the accommodation portion310. The fixing protrusion430may be accommodated in the fixing hole320. For example, two fixing holes320may be provided in the bottom surface310aof the accommodation portion310so as to be spaced apart from each other, and two fixing protrusions430each having a circular cross-section may be provided on the bottom surface of the sensor housing420. In particular, the fixing protrusion430may be coupled to the fixing hole320in an interference-fit manner. As described above, the fixing protrusions430are accommodated (inserted) into the fixing holes320, respectively, when the temperature measurement module400is seated in the accommodation portion310. Therefore, it is possible to obtain an advantageous effect of stably maintaining the state in which the temperature measurement module400is seated. In addition, when the posture and the position of the temperature measurement module400are misaligned, the fixing protrusion430cannot be inserted into the fixing hole320, and the temperature measurement module400protrudes in an abnormal posture. Therefore, the operator may easily recognize whether the temperature measurement module400is incorrectly assembled. In addition, according to the exemplary embodiment of the present disclosure, guide protrusions330may be provided on a lateral wall surface of the accommodation portion310, and guide grooves440may be provided in a lateral surface of the sensor housing420. The guide protrusion330may be accommodated in the guide groove440. For example, two guide protrusions330may be provided on the lateral wall surface of the accommodation portion310so as to face each other, and two guide grooves440may be provided on the lateral surface of the sensor housing420. Since the guide protrusions330are provided on the accommodation portion310and the guide grooves440are provided in the sensor housing420as described above, the temperature measurement module400may be accommodated in the accommodation portion310only in the state in which the guide protrusions330and the guide grooves440are aligned (in the vertical direction). Therefore, it is possible to obtain an advantageous effect of improving the accuracy in assembling the temperature measurement module400and minimizing the incorrect assembly. Meanwhile, according to another embodiment of the present disclosure, the temperature measurement module400may be coupled to the accommodation portion310in a snap-fit manner. Referring toFIGS.10and11, coupling holes450may penetrate the sensor housing420, and snap-fit coupling portions340may be provided on the bottom surface310aof the accommodation portion310. The snap-fit coupling portion340may be coupled to the coupling hole450in a snap-fit manner. The snap-fit coupling portion340may be elastically coupled to the coupling hole450in a snap-fit manner by using elasticity of a material (e.g., a plastic material) thereof. The present disclosure is not restricted or limited by the shape and structure of the snap-fit coupling portion340. As described above, the snap-fit coupling portions340are coupled to the coupling holes450, respectively, when the temperature measurement module400is seated in the accommodation portion310. Therefore, it is possible to obtain an advantageous effect of stably maintaining the state in which the temperature measurement module400is seated. In addition, when the posture and the position of the temperature measurement module400are misaligned, the snap-fit coupling portion340cannot be inserted into the coupling hole450, and the temperature measurement module400protrudes in an abnormal posture. Therefore, the operator may easily recognize whether the temperature measurement module400is incorrectly assembled. According to the embodiment of the present disclosure described above, it is possible to obtain an advantageous effect of simplifying the structure of the busbar unit and the process of assembling the busbar unit and improving the stability and reliability of the busbar unit. In particular, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of easily mounting the temperature measurement module regardless of the structure for winding the stator coil. In addition, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of making it possible to use the temperature measurement module in common and minimizing the incorrect assembly of the temperature measurement module. In addition, according to the embodiment of the present disclosure, it is possible to obtain an advantageous effect of improving the performance and accuracy of the temperature measurement module. While the embodiments have been described above, the embodiments are just illustrative and not intended to limit the present disclosure. It can be appreciated by those skilled in the art that various modifications and applications, which are not described above, may be made to the present embodiment without departing from the intrinsic features of the present embodiment. For example, the respective constituent elements specifically described in the embodiments may be modified and then carried out. Further, it should be interpreted that the differences related to the modifications and applications are included in the scope of the present disclosure defined by the appended claims. | 19,282 |
11863029 | DESCRIPTION OF REFERENCE NUMERALS 100: motor rotor;200: motor housing;300: main bearing;110: rotor body;120: conductive bearing;130: conductive pillar;140: bearing housing;150: grounding bracket;160: elastic conductive member;170: first fastener;180: second fastener;190: motor shaft;111: shaft hole;112: boss;113: cooling path;121: outer ring;122: steel ball;123: inner ring;131: first plane;132: stop part;133: step part;141: mounting cavity;142: bearing housing body;143: base;144: groove;151: positioning hole;152: body part;153: connection part;1431: limiting groove;1511: second plane;1531: avoidance groove;1532: second mounting hole;1533: third mounting hole. DESCRIPTION OF EMBODIMENTS Terms used in embodiments of this application are merely used to explain specific embodiments of this application, but are not intended to limit this application. FIG.1is a schematic diagram of a structure of a motor according to an embodiment of this application, andFIG.2is a partially enlarged view of I inFIG.1. Refer toFIG.1andFIG.2. In a conventional technology, the motor includes a motor rotor100and a stator, the stator is movably sleeved on an outer periphery of the motor rotor100, and the motor rotor100is connected to loads such as wheels. The motor rotor100includes a motor shaft190, an iron core and an excitation winding that are sleeved on the motor shaft, and the like. The motor shaft190of the motor rotor100is connected to loads such as wheels, to drive, when the motor shaft190rotates, the wheels to rotate. During working, the stator generates a rotating magnetic field in an air gap between the stator and the motor rotor100. When a direct current is applied to the excitation winding of the motor rotor100, a static magnetic field with constant polarity is generated. Under an action of armature reaction, the motor rotor100generates a torque relative to the stator, so that the motor shaft190drives loads such as wheels to move. In actual application, the stator of the motor includes at least a motor housing200. In this embodiment of this application, the motor housing200of the motor is mainly used as the stator of the motor. The following describes a structure of the motor by using the motor housing200as the stator. In an embodiment, the motor housing200and the motor rotor100are movably connected to each other by using a main bearing300. For example, an outer ring of the main bearing300interference fits with an inner wall of the motor housing200, and an inner ring of the main bearing300interference fits with an outer wall of the motor rotor100such as the motor shaft190. Therefore, in a high-speed running process of the motor rotor100, the motor housing200can maintain static under an action of the main bearing300, to ensure that the motor rotor100rotates stably around an axis l in the motor housing200. It should be noted that, as shown inFIG.1, the axis l may be an axis of the motor rotor100. Refer toFIG.2. When a PWM inverter supplies power to the excitation winding of the motor rotor100, a high-frequency common-mode voltage is generated. The high-frequency common-mode voltage is coupled to the motor rotor100by using parasitic capacitance of the motor, to form a shaft voltage. When the shaft voltage exceeds a breakdown voltage threshold of an oil film on the motor rotor100, a shaft current is formed on the motor rotor100. When the shaft current is discharged to the main bearing300on the outer periphery of the motor rotor100, partial discharging is performed between a steel ball and a race of the main bearing300, and an electric fusion pit is formed on the race. Consequently, the main bearing300is electrically corroded, and a service life of the main bearing300is affected. To prevent the main bearing300from being electrically corroded by the shaft current, a conductive bearing120and a conductive spring (not shown in the figure) are disposed on the conventional motor rotor100. The conductive bearing120is disposed in a shaft hole111of the motor rotor100, and the conductive bearing120is close to an end of the motor rotor100. An outer ring121of the conductive bearing120abuts on an inner wall of the shaft hole111. In addition, a conductive spring is pressed against an inner ring123of the conductive bearing120, and the other end of the conductive spring is grounded. For example, the other end of the conductive spring may be connected to ground or reference ground (for example, the motor housing200). In this way, a resistance of a conductive loop formed from the motor rotor100, the conductive bearing120, and the conductive spring to the ground (or the reference ground) is less than a resistance of a conductive loop formed between the motor rotor100and the main bearing300. Therefore, the shaft current on the motor rotor100is mostly transmitted and discharged by using the conductive bearing120and the conductive spring, and strength of a current discharged to the main bearing300is reduced, so that the main bearing300is prevented from being electrically corroded by the shaft current. In actual application, a difference between the conductive bearing120and the main bearing300lies in that the conductive bearing120further includes two sealing rings (not shown in the figure) disposed oppositely to each other between the outer ring121and the inner ring123. There is a gap between the outer ring121and the inner ring123, and the two sealing rings each are disposed between two ends of the outer ring121and the inner ring123in an axis direction (namely, a thickness direction), namely, the two sealing rings each are disposed in gaps on two sides of the conductive bearing120in the axis direction (namely, the thickness direction). A steel ball122in the conductive bearing120is sealed between the two sealing rings, and conductive grease (not shown in the figure) is filled in a gap between the steel ball122and each of the outer ring121and the inner ring123. The shaft current discharged from the motor rotor100to the outer ring121of the conductive bearing120may be transmitted quickly to the inner ring123by using the conductive grease and the steel ball122, so that a conductive property of the conductive bearing120is improved. Under an action of elastic force, a tongue of the conductive spring is pressed against a surface that is of the inner ring123of the conductive bearing120and that faces away from the outer ring121. In this way, the current on the motor rotor100is transmitted to the conductive spring sequentially by using the outer ring121, the conductive grease, the steel ball122, and the inner ring123of the conductive bearing120, and is finally discharged to the ground or the reference ground by using the conductive spring. However, a surface of the inner ring123of the conductive bearing120is a curved surface, and a surface of the tongue of the conductive spring is a flat surface. When the tongue of the conductive spring is pressed against the inner ring123of the conductive bearing120, two ends of the tongue only in a width direction are in contact with the surface of the inner ring123, namely, the conductive spring is in linear contact with the inner ring123of the conductive bearing120. In this case, in the high-speed running process of the motor rotor100, the conductive bearing120moves axially and radially with the motor rotor100, and the conductive spring cannot be in stable contact with the inner ring123of the conductive bearing120. Consequently, the conductive bearing120cannot be stably grounded, and both the conductive bearing120and the main bearing300are electrically corroded by the shaft current. In addition, because a point at which the conductive spring is pressed against the conductive bearing120is not in a diameter direction of the steel ball122, namely, force exerted between the conductive spring and the conductive bearing120deviates from the diameter direction of the steel ball122, the conductive bearing120is subject to offset loading force. The offset loading force causes the inner ring123of the conductive bearing120to be skewed, and consequently the gap between the inner ring123and the outer ring121is not equal at all circumferential positions. As a result, the inner ring123, the steel ball122, the outer ring121, and the like of the conductive bearing120are abnormally worn, and the two sealing rings on the conductive bearing120in the thickness direction are also worn due to uneven force. Consequently, the conductive grease in the conductive bearing120overflows from the two sides of the conductive bearing120to affect a service life and the conductive property of the conductive bearing120. The embodiments of this application provide a motor rotor, a motor, and a vehicle. A conductive pillar passes through an inner ring of a conductive bearing, an outer wall of the conductive pillar interference fits with the inner ring of the conductive bearing, and an end of the conductive pillar is grounded. In this way, it is ensured that a shaft current on a rotor body is transmitted and discharged by using the conductive bearing and the conductive pillar, to prevent a main bearing of the motor from being electrically corroded by the shaft current. In addition, the conductive bearing is sleeved on the grounded conductive pillar, so that the inner ring of the conductive bearing can interference fit with the outer wall of the conductive pillar, to enable the inner ring of the conductive bearing to be closely attached to the outer wall of the conductive pillar, and avoid the following case: In a high-speed rotation process of the rotor body, the conductive bearing is in unstable contact with the conductive pillar because the rotor body drives the conductive bearing to move axially and radially, and consequently the shaft current cannot be discharged. In addition, an outer ring of the conductive bearing interference fits with an inner ring of a shaft hole. This also further improves closeness of contact between the conductive bearing and the rotor body, and ensures that the shaft current on the rotor body can be stably transmitted to the conductive bearing. In other words, the motor rotor in the embodiments of this application can ensure that the rotor body, the conductive bearing, and the conductive pillar are always electrically connected in a running process of the motor rotor, to ensure that the shaft current on the rotor body is transmitted and discharged by using the conductive bearing and the conductive pillar. In addition, compared with the conventional technology in which the spring is pressed against the inner ring of the conductive bearing, in the embodiments of this application, the outer wall of the conductive pillar circumferentially abuts on the inner ring of the conductive bearing evenly, so that force is evenly exerted on the conductive bearing, and no offset loading force occurs. Therefore, the conductive bearing is prevented from being damaged due to concentrated stress, and the conductive bearing is prevented from being abnormally worn due to the offset loading force, to prevent the conductive grease from overflowing because the sealing rings on the conductive bearing are worn, and prolong the service life of the conductive bearing. The following describes in detail specific structures of the motor rotor, the motor, and the vehicle that are provided in the embodiments of this application. FIG.3is a schematic diagram of a structure of a part inFIG.2. Refer toFIG.1toFIG.3. A motor rotor100in an embodiment of this application includes a rotor body110, a conductive bearing120, and a conductive pillar130. Refer toFIG.1. In actual application, the rotor body110includes a motor shaft190, an iron core and an excitation winding that are sleeved on the motor shaft190, and the like. A component such as the iron core and the excitation winding is sleeved on a partial outer wall of the motor shaft190. For example, two ends of the motor shaft190in an axis direction extend out of two end faces of the iron core. In this way, the component such as the iron core and the excitation winding does not exist on partial outer walls of the motor shaft190that are close to the two ends. Refer toFIG.1andFIG.2. The rotor body110in this embodiment of this application has shaft hole111extending in an axis direction. The shaft hole111is disposed on an axis l of the rotor body110, and two ends of the shaft hole111penetrate through two end faces of the rotor body110in the axis direction. For example, the shaft hole111is disposed in the motor shaft190of the rotor body110, and the shaft hole111extends to two end faces of the motor shaft190along the axis l of the motor shaft190. The conductive bearing120is built in the shaft hole111. For ease of description, two ends of the rotor body110that are disposed oppositely to each other in an extension direction may be respectively used as a first end of the rotor body110and a second end of the rotor body110. It may be understood that there may be one or two conductive bearings120in this embodiment of this application. When there is one conductive bearing120, the conductive bearing120may be built in the shaft hole111, and the conductive bearing120is close to one of the ports of the rotor body110. For example, the conductive bearing120is close to the first end of the rotor body110, namely, the conductive bearing120is located in a part of the motor shaft190that extends out of the iron core. When there are two conductive bearings120, the two conductive bearings120are respectively built in the rotor body110, and are close to the two ports of the rotor body110. For example, one of the conductive bearings120is close to the first end of the rotor body110, and the other conductive bearing120is close to the second end of the rotor body110, namely, the two conductive bearings120are respectively built in two ends of the motor shaft190that extend into the iron core. In this embodiment of this application, a quantity of conductive bearings120is not limiting, and may be adjusted based on an actual requirement. Refer toFIG.3. In actual application, the conductive bearing120includes an inner ring123, a steel ball122, an outer ring121, two sealing rings (not shown in the figure), and conductive grease (not shown in the figure). The outer ring121is sleeved on an outer periphery of the inner ring123, the steel ball122and the conductive grease are located in a gap (which may also be referred to as a race) between the outer ring121and the inner ring123, and the two sealing rings each are disposed between two ends of the outer ring121and the inner ring123in an axis direction (namely, a thickness direction), so that the steel ball122and the conductive grease of the conductive bearing120are sealed between the two sealing rings. A shaft current discharged from the motor rotor100to the outer ring121of the conductive bearing120may be quickly transmitted to the inner ring123by using the conductive grease and the steel ball122, to improve a conductive property of the conductive bearing120. For a specific structure of the conductive bearing120, refer to a conventional technology directly. Details are not described herein again. Still refer toFIG.3. The outer ring121of the conductive bearing120interference fits with an inner wall of the shaft hole111, the conductive pillar130internally passes through the conductive bearing120, and the inner ring123of the conductive bearing120interference fits with an outer wall of the conductive pillar130. The inner wall of the shaft hole111may be understood as an inner wall of the rotor body110. It may be understood that, in an embodiment, the outer ring121of the conductive bearing120directly interference fits with the inner wall of the shaft hole111, namely, the outer ring121of the conductive bearing120is in direct contact with the inner wall of the shaft hole111. In another embodiment, the outer ring121of the conductive bearing120indirectly interference fits with the inner wall of the shaft hole111, namely, the outer ring121of the conductive bearing120is in indirect contact with the inner wall of the shaft hole111(as shown inFIG.3, for details, refer to a manner that is mentioned below and in which interference fitting between the outer ring121of the conductive bearing120and the inner wall of the shaft hole111is implemented by using a side wall of a bearing housing140). The following first describes a structure in which the outer ring121of the conductive bearing120directly interference fits with the inner wall of the shaft hole111. The rotor body110in this embodiment of this application and the outer ring121of the conductive bearing120are static relative to each other. For example, in a process in which the rotor body110rotates around the axis at a high speed, the outer ring121of the conductive bearing120rotates synchronously with the rotor body110. In addition, the inner ring123of the conductive bearing120and the conductive pillar130are static relative to each other. FIG.4is a schematic diagram of a structure of a conductive pillar inFIG.3, andFIG.5is a top view ofFIG.4. Refer toFIG.3toFIG.5. The conductive pillar130is columnar, and the conductive pillar130is conductive. For example, the conductive pillar130may be made of conductive metal such as iron, copper, or steel. In addition, the conductive pillar130may be of a hollow structure, for example, a through hole is disposed on an axis of the conductive pillar130, to reduce a weight of the conductive pillar130, and facilitate mounting and removal of the conductive pillar130. It may be understood that, after the conductive pillar130is assembled on the rotor body110, the axis of the conductive pillar130overlaps the axis l of the rotor body110. An end of the conductive pillar130in this embodiment of this application is grounded. It should be noted that “being grounded” herein may be connected to reference ground or ground. For example, an end of the conductive pillar130penetrates through one of the ports of the rotor body110, and is connected to a motor housing200of the motor by using a conductive member such as a conductor. In actual application, when the motor in this embodiment of this application is applied to a vehicle, the motor housing200of the motor is in contact with a chassis of the vehicle, and the vehicle is on a road, the chassis of the vehicle is in contact with the ground. In this case, an end of the conductive pillar130is connected to the motor housing200by using a conductive member such as a conductor, so that the conductive pillar130is grounded. When the motor housing200is not in contact with the chassis of the vehicle, namely, when the motor housing200and the chassis of the vehicle are spaced apart, because the motor housing200is not live, the motor housing200may be used as the reference ground. In this way, an end of the conductive pillar130is connected to the motor housing200of the motor by using a conductive member such as a conductor, to ensure that the conductive pillar130accesses the reference ground whose potential is zero. When a shaft current is generated on the motor rotor100, the shaft current is first discharged to the outer ring121of the conductive bearing120by using the rotor body110, then flows to the conductive pillar130sequentially by using the steel ball122, the conductive grease, and the inner ring123of the conductive bearing120, and is finally discharged by using the conductive pillar130. Because the conductive pillar130is grounded, a resistance of a conductive loop formed from the rotor body110, the conductive bearing120, and the conductive pillar130to the ground (or the reference ground) is less than a resistance of a conductive loop formed between the rotor body110and a main bearing300. Therefore, the current on the rotor body110is mostly transmitted and discharged by using the conductive bearing120and the conductive pillar130, and strength of a current flowing to the main bearing300is reduced, so that the main bearing300of the motor100is prevented from being electrically corroded by the shaft current. In this embodiment of this application, the conductive bearing120is sleeved on the grounded conductive pillar130, so that the inner ring123of the conductive bearing120can interference fit with the outer wall of the conductive pillar130, to enable the inner ring123of the conductive bearing120to be closely attached to the outer wall of the conductive pillar130, and avoid the following case: In the high-speed rotation process of the rotor body110, the conductive bearing120is in unstable contact with the conductive pillar130because the rotor body110drives the conductive bearing120to move axially and radially, and consequently the shaft current cannot be discharged. In addition, the outer ring121of the conductive bearing120interference fits with the inner wall of the shaft hole111. This also further improves closeness of contact between the conductive bearing120and the rotor body110, and ensures that the shaft current on the rotor body110can be stably transmitted to the conductive bearing120. In other words, the motor rotor100in this embodiment of this application can ensure that the rotor body110, the conductive bearing120, and the conductive pillar130are always electrically connected in a running process of the motor rotor100, to ensure that the shaft current on the rotor body110is successfully discharged by using the conductive bearing120and the conductive pillar130. In addition, compared with the conventional technology in which the conductive spring is pressed against the inner ring123of the conductive bearing120, in this embodiment of this application, the outer wall of the conductive pillar130circumferentially abuts on the inner ring123of the conductive bearing120evenly, so that force is evenly exerted on the conductive bearing120, and no offset loading force occurs. Therefore, the conductive bearing120is prevented from being damaged due to concentrated stress, and the conductive bearing120is prevented from being abnormally worn due to the offset loading force, to prevent the conductive grease from overflowing because the sealing rings on the conductive bearing120are worn, and prolong a service life of the conductive bearing120. FIG.6is a schematic diagram of a structure of a grounding bracket inFIG.3. Refer toFIG.3andFIG.6. To facilitate grounding of an end of the conductive pillar130, the motor rotor100in this embodiment of this application may further include a grounding bracket150. The grounding bracket150is located at an end of the rotor body110, one end of the grounding bracket150is electrically connected to the conductive pillar130, and the other end of the grounding bracket150is connected to the motor housing200of the motor. The grounding bracket150in this embodiment of this application is close to an end of the rotor body110that is provided with the conductive bearing120, and the grounding bracket150is located outside the rotor body110. For example, when the conductive bearing120is adjacent to the first end of the rotor body110, the grounding bracket150is located outside the first end of the rotor body110. Correspondingly, when the conductive bearing120is adjacent to the second end of the rotor body110, the grounding bracket150is located outside the second end of the rotor body110. During specific disposition, one end of the conductive pillar130extends into the shaft hole111of the rotor body110and fits with the conductive bearing120, and the other end of the conductive pillar130may extend out of the end of the rotor body110and is electrically connected to the grounding bracket150. For example, when the conductive bearing120is adjacent to the first end of the rotor body110, an end of the conductive pillar130extends out of the first end of the rotor body110and is electrically connected to the grounding bracket150outside the first end of the rotor body110. It may be learned from the foregoing that, when the motor in this embodiment of this application is applied to a vehicle such as an electric vehicle, and the motor housing200of the motor is always connected to a chassis of the vehicle, if an end of the conductive pillar130is electrically connected to the grounding bracket150, and the grounding bracket150is connected to the motor housing200of the motor, the conductive pillar130may be electrically connected to the ground by using the grounding bracket150and the motor housing200. When the motor housing200and the chassis of the vehicle are spaced apart, the motor housing200may be directly used as the reference ground whose potential is zero. In this way, the conductive pillar130may be electrically connected, by using the grounding bracket150, to the reference ground whose potential is zero. Therefore, it is ensured that the shaft current on the conductive pillar130can be discharged by using the grounding bracket150and the motor housing200, and a grounding process of the conductive pillar130is simplified, to improve assembling efficiency of the motor rotor100. The conductive pillar130and the grounding bracket150may be electrically connected to each other by using a conductive member. The conductive member may be a conductor. Refer toFIG.3. In some examples, the motor rotor100may further include an elastic conductive member160. The elastic conductive member160may be used as a conductive member. One end of the elastic conductive member160is electrically connected to the conductive pillar130, and the other end of the elastic conductive member160is electrically connected to the grounding bracket150. During specific connection, one end of the elastic conductive member160may be fastened to the conductive pillar130through bonding, clamping, screw connection, or the like, and the other end of the elastic conductive member160may also be fastened to the grounding bracket150through bonding, clamping, screw connection, or the like. It should be noted that, when the elastic conductive member160is bonded to the conductive pillar130, adhesive used to bond the elastic conductive member160to the conductive pillar130needs to be conductive adhesive, to ensure that a current path is formed between the conductive pillar130and the elastic conductive member160. For example, a composition material of the conductive adhesive may include but is not limited to one or more of an epoxy resin, an acrylic resin, and polyurethane. An example in which the elastic conductive member160is electrically connected to the grounding bracket150is used. Refer toFIG.3andFIG.6. A first mounting hole (not shown in the figure) may be disposed on the elastic conductive member160, a second mounting hole1532that matches the first mounting hole is disposed on the grounding bracket150, and the elastic conductive member160is fastened to the grounding bracket150by using a first fastener170that passes through the first mounting hole and the second mounting hole1532. It may be understood that the first fastener170is a conductive connector. For example, the fastener may be a screw, a rivet, or a bolt, to implement an electrical connection between the elastic conductive member160and the grounding bracket150. The elastic conductive member160may include but is not limited to any one of a rubber member and a silicone member. For example, the elastic conductive member160may be another elastic conductive member such as a metal spring. In addition, the grounding bracket150may also be fastened to the motor housing200through bonding, clamping, screw connection, or the like. For example, as shown inFIG.3andFIG.6, a third mounting hole1533may be disposed on the grounding bracket150. Correspondingly, a fourth mounting hole (not shown in the figure) that matches the third mounting hole1533is disposed on the motor housing200. The grounding bracket150is fastened to the motor housing200by using a second fastener180that passes through the third mounting hole1533and the fourth mounting hole. In this way, stability of a connection between the grounding bracket150and the motor housing200is ensured, and an assembling structure between the grounding bracket150and the motor housing200is simplified, to improve assembling efficiency of the motor. The second fastener180may include but is not limited to a conductive fastener such as a bolt, a screw, or a rivet. It should be noted that, when the grounding bracket150is bonded to the motor housing200, adhesive used to bond the grounding bracket150to the motor housing200needs to be conductive adhesive, to ensure that a current path is formed between the grounding bracket150and the motor housing200. In this embodiment of this application, the elastic conductive member160is disposed between the conductive pillar130and the grounding bracket150. When an electrical connection between the conductive pillar130and the grounding bracket150is implemented, because the elastic conductive member160has a length used for cushioning, when the rotor body110drives the conductive bearing120and the conductive pillar130to move axially and radially in the high-speed rotation process, the length of the elastic conductive member160is adaptively adjusted with movement of the conductive pillar130, and the elastic conductive member160is not torn. Therefore, it is ensured that the electrical connection between the conductive pillar130and the grounding bracket150is stable. Still refer toFIG.3andFIG.6. The grounding bracket150in this embodiment of this application has a positioning hole151. An end of the conductive pillar130may extend out of the end of the rotor body110and pass through the positioning hole151, so that radial movement of the conductive pillar130in the rotor body110is limited, to improve radial stability of the conductive pillar130. It should be noted that a radial direction of the rotor body110is consistent with a radial direction of the conductive pillar130. In this case, when the conductive pillar130internally passes through the positioning hole151of the grounding bracket150, radial movement of the conductive pillar130relative to the conductive pillar130is also correspondingly limited, to prevent the conductive pillar130from shaking from side to side or deviating. The outer wall of the conductive pillar130may clearance fit with an inner wall of the positioning hole151. Therefore, in the high-speed rotation process, the rotor body110can drive the conductive bearing120and the conductive pillar130to move freely. This effectively prevents a rigid connection between the conductive pillar130and the grounding bracket150from hampering movement of the inner ring123of the conductive bearing120, to ensure that a structure of the conductive bearing120is not damaged. To further improve stability of the conductive pillar130, a limiting structure may be further disposed between the conductive pillar130and the positioning hole151in this embodiment of this application. The limiting structure is used to limit rotation of the conductive pillar130around the axis in the positioning hole151, to ensure circumferential stability of the conductive pillar130. In this way, stability of contact between the conductive pillar130and the inner ring123of the conductive bearing120is ensured, and stability of the electrical connection between the conductive pillar130and the grounding bracket150is ensured, to avoid the following case: When the conductive pillar130rotates around the axis of the conductive pillar130, an end of a conductive member such as the elastic conductive member160or a conductor is separated from the conductive pillar130. In an embodiment, a positioning protrusion (not shown in the figure) may be disposed on a side wall of the conductive pillar130. Correspondingly, a positioning groove (not shown in the figure) that matches the positioning protrusion is disposed on the inner wall of the positioning hole151. After an end of the conductive pillar130internally passes through the positioning hole151, the positioning protrusion extends into the positioning groove. In this example, the positioning protrusion and the positioning groove are used as the limiting structure to limit rotation of the conductive pillar130around the axis of the conductive pillar130in the positioning hole151. FIG.7is a top view ofFIG.6. Refer toFIG.3,FIG.4, andFIG.7. In another embodiment, at least a partial outer wall of the conductive pillar130that is located inside the positioning hole151forms a first plane131(as shown inFIG.4), and correspondingly, at least a partial inner wall of the positioning hole151forms a second plane1511(as shown inFIG.7) corresponding to the first plane131. The limiting structure includes the first plane131and the second plane1511. In this embodiment of this application, the limiting structure is set as a plane on a partial side wall of the conductive pillar130that is located inside the positioning hole151, and a plane on at least a partial inner wall of the positioning hole151. This effectively prevents the conductive pillar130from rotating around the axis l in the positioning hole151, and also simplifies the limiting structure. Therefore, manufacturing and assembling efficiency of the entire motor rotor100are improved. Refer toFIG.5. A plurality of first planes131may be formed on the side wall of the conductive pillar130, and the plurality of first planes131are disposed at intervals around the axis of the conductive pillar130. Correspondingly, as shown inFIG.7, a plurality of second planes1511are formed on the inner wall of the positioning hole151, the plurality of second planes1511are disposed at intervals around an axis of the positioning hole151, and the plurality of first planes131are respectively opposite to the corresponding second planes1511, to ensure that the conductive pillar130does not rotate in the positioning hole151. For example, as shown inFIG.5, two first planes131may be formed on the side wall of the conductive pillar130, and the two first planes131are disposed oppositely to each other on two sides of the axis of the conductive pillar130. Correspondingly, as shown inFIG.7, two second planes1511are formed on the inner wall of the positioning hole151, and the two second planes1511are disposed oppositely to each other on two sides of the axis of the positioning hole151. An end of the conductive pillar130penetrates into the positioning hole151of the grounding bracket150, and one first plane131of the conductive pillar130fits with one second plane1511of the grounding bracket150, and the other first plane131of the conductive pillar130fits with the other second plane1511of the grounding bracket150. This further improves a limiting effect of the limiting structure on rotation of the conductive pillar130, and ensures that the conductive pillar130does not rotate around the axis during high-speed rotation of the rotor body110, namely, ensures that the conductive pillar130is static in the running process of the motor rotor100. Therefore, stability of the electrical connection between the conductive pillar130and each of the conductive bearing120and the grounding bracket150is further improved. Refer toFIG.6andFIG.7. During specific disposition, the grounding bracket150may include a body part152and a connection part153, the positioning hole151is formed on the body part152, and an end of the conductive pillar130penetrates into the positioning hole151on the body part152, to limit radial movement of the conductive pillar130in the rotor body110. One end of the connection part153is connected to the body part152, and the other end of the connection part153is connected to the motor housing200. There may be one or more connection parts153, and the plurality of connection parts153are disposed at intervals around an outer periphery of the positioning hole151. For example, there are N connection parts153, and N≥3, namely, there may be at least three connection parts153. The at least three connection parts153are disposed at intervals around the outer periphery of the positioning hole151, one end of each connection part153is connected to the body part152, the other end of each connection part153extends in a direction away from the axis of the positioning hole151, and the other end of each connection part153is used to connect to the motor housing200. An example in which there are three connection parts153is used. The three connection parts153may be distributed at intervals on an outer periphery of the body part152around the axis of the positioning hole151, so that lines between points at which the grounding bracket150is connected to the motor housing200form a triangle, to improve stability of the connection between the grounding bracket150and the motor housing200. The three connection parts153may be evenly distributed on the outer periphery of the body part152, namely, an angle between two adjacent connection parts153is 120°, to facilitate manufacturing of the grounding bracket150. In actual application, the motor housing200has three mounting holes. In this way, three connection parts153are disposed on an end of the body part152. This improves strength of the connection between the grounding bracket150and the motor housing200, and fully uses a structure of the motor housing200. In this embodiment of this application, the grounding bracket150is set as the body part152and the connection part153connected to an end of the body part152, and the grounding bracket150and the motor housing200are stably connected to each other by using the connection part153. This improves strength of the connection between the grounding bracket150and the motor housing200. In addition, the positioning hole151is disposed on the body part152connected to an end of the connection part153. Therefore, a limiting effect on the conductive pillar130is implemented, and structural strength of the grounding bracket150is ensured, so that a service life of the grounding bracket150is prolonged. In some examples, the third mounting hole1533may be disposed at an end of each connection part153. Correspondingly, three fourth mounting holes respectively corresponding to the third mounting holes1533are disposed on the motor housing200. In this way, the second fastener180may pass through each pair of third mounting hole1533and fourth mounting hole that is coaxial with the third mounting hole1533, to further improve strength of the connection between the grounding bracket150and the motor housing200. In addition, an end of the elastic conductive member160may be connected to any connection part153, to improve assembling flexibility of the elastic conductive member160. For example, the second mounting hole1532may be disposed on each of the three connection parts153of the grounding bracket150, and the first mounting hole on the elastic conductive member160may fit with any second mounting hole1532. In this way, the first fastener170passes through the first mounting hole of the elastic conductive member160and the second mounting hole1532, to fasten an end of the elastic conductive member160to the connection part153. It should be noted that the grounding bracket150may be an integrally formed member, namely, the main part152and the at least three connection parts153are integrally injection molded, to improve structural strength of the grounding bracket150and simplify an assembling process of the grounding bracket150. In actual application, in the high-speed running process, the rotor body110is prone to move axially. When an end of the rotor body110moves in a direction close to the grounding bracket150, the rotor body110inevitably collides with the connection part153of the grounding bracket150repeatedly, to cause damage to a structure of the grounding bracket150. Based on this, as shown inFIG.6andFIG.7, an avoidance groove1531may be formed on a side of each connection part153that faces the rotor body110, and the avoidance groove1531is used to allow an end of the rotor body110to enter. In this way, when the rotor body110moves axially in a direction of the connection part153in the high-speed running process, the rotor body110may enter the avoidance groove1531without directly colliding with a surface of the connection part153, to avoid damage to the structure of the grounding bracket150. In addition, disposition of the avoidance groove1531also prevents the grounding bracket150from being interfered by the rotor body110in a mounting process. The following describes a structure in which the outer ring121of the conductive bearing120indirectly interference fits with the inner wall of the shaft hole111. FIG.8is a schematic diagram of a structure of a bearing housing inFIG.3, andFIG.9is a sectional view ofFIG.8. Refer toFIG.3,FIG.8, andFIG.9. The motor rotor100in this embodiment of this application may further include a bearing housing140. The bearing housing140is disposed in the shaft hole111, and the conductive bearing120is located in a mounting cavity141of the bearing housing140. An outer wall of the bearing housing140interference fits with the inner wall of the shaft hole111, and the outer ring121of the conductive bearing120interference fits with an inner wall of the bearing housing140. In other words, the conductive bearing120is fastened in the shaft hole111of the rotor body110by using the bearing housing140, and the outer ring121of the conductive bearing120interference fits with the inner wall of the shaft hole111by using a side wall of the bearing housing140. In this way, the bearing housing140, the rotor body110, and the outer ring121of the conductive bearing120are static relative to each other. For example, in the process in which the rotor body110rotates around the axis at a high speed, the bearing housing140and the outer ring121of the conductive bearing120rotate synchronously with the rotor body110. In this embodiment of this application, the bearing housing140is disposed in the shaft hole111, and the conductive bearing120is mounted in the bearing housing140. This facilitates assembling of the conductive bearing120in the shaft hole111of the rotor body110, and also improves axial stability of the conductive bearing120and the conductive pillar130in the shaft hole111. In addition, the outer wall of the bearing housing140interference fits with the inner wall of the shaft hole111, and the outer ring121of the conductive bearing120interference fits with the inner wall of the bearing housing140, so that the bearing housing140is in closer contact with each of the rotor body110and the conductive bearing120. Therefore, it is ensured that the shaft current on the rotor body110can be successfully transmitted to the bearing housing140and the conductive bearing120, and assembling stability of the bearing housing140in the shaft hole111and assembling stability of the conductive bearing120in the bearing housing140are also improved. Refer toFIG.3andFIG.8. Further, a cooling path113is formed between the outer wall of the bearing housing140and the inner wall of the shaft hole111in this embodiment of this application. The cooling path113extends in the axis direction of the rotor body110, and two ends of the cooling path113in an extension direction both communicate with the shaft hole111of the rotor body110. The cooling path113is used to allow a cooling medium to flow. It may be understood that the cooling medium may be oil or cooling water. For example, a groove144is disposed on the outer wall of the bearing housing140, and two ends of the groove144run through two ends of the bearing housing140in an extension direction. In this way, an inner wall of the groove144and the inner wall of the shaft hole111jointly surround the cooling path113. The extension direction of the bearing housing140is consistent with the axis direction of the rotor body110. It may be understood that the groove144may be a structure integrally injection molded when the bearing housing140is manufactured. Certainly, in some examples, cutting may be performed on the outer wall of the manufactured bearing housing140to form the groove144on a partial side wall. In actual application, because the outer wall of the bearing housing140is a curved surface, a partial outer wall of the bearing housing140may be cut into a flat surface, and the flat surface may be considered as the groove144with a relatively shallow depth. Two sides of the flat surface in a circumferential direction of the bearing housing140abut on the inner wall of the shaft hole111, so that the flat surface and the inner wall of the shaft hole111surround the cooling path113. When heat of the motor rotor100needs to be dissipated, the cooling medium such as oil may be introduced into the shaft hole111of the rotor body110. The oil flows from the first end of the rotor body110to the shaft hole111. When the oil flows to the bearing housing140, the oil may enter the cooling path113from one end of the cooling path113to perform heat exchange with the outer wall of the bearing housing140, is drained from the other end of the cooling path113to the shaft hole111, and is finally drained from the second end of the rotor body110. It may be understood that the conductive bearing120and the conductive pillar130inside the bearing housing140transmit heat to the outer wall of the bearing housing140by using the inner wall of the bearing housing140. In this way, after heat exchange is performed between the oil in the cooling path113and the outer wall of the bearing housing140, heat of the bearing housing140and the conductive bearing120and the conductive pillar130inside the bearing housing140may be removed, to dissipate heat for the bearing housing140, the conductive bearing120, and the conductive pillar130. In this embodiment of this application, the cooling path113is formed between the outer wall of the bearing housing140and the inner wall of the shaft hole111. In this way, the cooling medium that is introduced into the shaft hole111may enter the cooling path113, to cool the bearing housing140, the conductive bearing120, and the conductive pillar130. Therefore, the following case is avoided: The conductive bearing120is heated and expanded in the high-speed running process of the motor rotor100, and consequently the steel ball122in the conductive bearing120cannot rotate normally and a conductivity of the conductive grease decreases. Therefore, it is ensured that the conductive bearing120and the conductive grease are stable. Still refer toFIG.3andFIG.8. The bearing housing140may include a bearing housing body142and a base143. An outer wall of the bearing housing body142interference fits with the inner wall of the shaft hole111. The bearing housing body142includes a first end and a second end that are disposed oppositely to each other in an extension direction. The first end of the bearing housing body142faces the grounding bracket150, and the first end is opened. The base143of the bearing housing140is disposed at the second end of the bearing housing body142. In other words, a first end of the bearing housing140is opened and faces the grounding bracket150, and a second end of the bearing housing140has the base143. The bearing housing body142and the base143jointly surround the mounting cavity141of the bearing housing140, and the conductive bearing120is located in the mounting cavity141. It should be noted that the first end and the second end of the bearing housing body142may also be considered as the first end and the second end of the bearing housing140. During specific assembling, the conductive bearing120may be mounted in the bearing housing140from an opening of the first end of the bearing housing140, and an end of the conductive pillar130extends into the mounting cavity141of the bearing housing140through the opening of the first end of the bearing housing140, and further interference fits with the inner ring123of the conductive bearing120. In this embodiment of this application, an end of the bearing housing140that faces the grounding bracket150is opened, to facilitate assembling of the conductive bearing120and the conductive pillar130. In addition, the base143of the bearing housing140plays a role of positioning the conductive bearing120axially. In other words, provided that the conductive bearing120is assembled on the base143, positioning of the conductive bearing120in the bearing housing140can be completed. This improves assembling efficiency of the conductive bearing120. An auxiliary hole (not shown in the figure) may be disposed on a side wall of the bearing housing body142that is close to the first end. The auxiliary hole is used to assist a mounting tool in grasping the bearing housing140. For example, when the bearing housing140needs to be mounted in the shaft hole111of the rotor body110, the mounting tool may extend into the auxiliary hole to exert force on the bearing housing140, so as to build the bearing housing140into a corresponding position in the shaft hole111. When the bearing housing140needs to be removed from the shaft hole111of the rotor body110, the mounting tool also extends into the auxiliary hole to grasp the bearing housing140, so as to quickly pull the bearing housing140out of the shaft hole111. The bearing housing140in this embodiment of this application may be an integrally formed member, namely, the bearing housing body142and the base143of the bearing housing140are integrally injection molded, to improve structural strength of the bearing housing140. Certainly, in this embodiment of this application, that the bearing housing body142and the base143are disposed separately is not ruled out. For example, the base143may be fastened to the second end of the bearing housing body142through screw connection, clamping, or the like. In an embodiment, an inner wall of the base143is recessed in a direction away from the first end of the bearing housing body142to form a limiting groove1431, and an end of the conductive pillar130extends into the limiting groove1431to limit radial movement of the conductive pillar130in the rotor body110. An opening size and a shape of the limiting groove1431may be respectively consistent with a radial size and a shape of the conductive pillar130. In this way, the outer wall of the conductive pillar130may be attached to an inner wall of the limiting groove1431, to further prevent an end of the conductive pillar130that faces the base143from shaking radially. One end of the conductive pillar130internally passes through the positioning hole151of the grounding bracket150, and the other end of the conductive pillar130extends into the limiting groove1431of the bearing housing140. This effectively limits radial movement of the conductive pillar130, and prevents the conductive pillar130from shaking from side to side radially in the high-speed running process of the rotor body110. Refer toFIG.9. When the limiting groove1431is disposed, a partial region of the base143may protrude in a direction away from the first end of the bearing housing body142. In this case, a recess part is formed on the inner wall of the base143. The recess part may be used as the limiting groove1431, and an inner wall of the recess part is the inner wall of the limiting groove1431. A protrusion part is formed on an outer wall of the base143, and a side wall of the protrusion part may be understood as an outer wall of the limiting groove1431. Certainly, in another example, a groove may be directly disposed on the inner wall of the base143, and the groove is used as the limiting groove1431. It should be noted that the inner wall (an inner surface) of the base143is a surface of the base143that is located inside the bearing housing140, and the outer wall (an outer surface) of the base143is a surface of the base143that is located outside the bearing housing140. Refer toFIG.4. In this embodiment of this application, a step part133is formed on the side wall of the conductive pillar130, and the step part133is located between the grounding bracket150and the base143of the motor rotor100. In other words, after two ends of the conductive pillar130are respectively assembled in the grounding bracket150and the bearing housing140, the step part133on the conductive pillar130is located on a side of the grounding bracket150that faces the bearing housing140. A distance between the step part133and the grounding bracket150is a first distance (shown by h1inFIG.3). A distance between an outer peripheral surface of the limiting groove1431and the end of the conductive pillar130that faces the base143is a second distance (shown by h2inFIG.3). It should be noted that the first distance h1is a vertical distance between a step surface (shown by a inFIG.4) of the step part133that faces the grounding bracket150and a surface of the body part152that faces the step part133. The second distance h2is a vertical distance between the outer peripheral surface of the limiting groove1431(shown by b inFIG.3andFIG.9) and an end face of the conductive pillar130that faces the base143. It should be noted that the outer peripheral surface of the limiting groove1431is an inner surface of the base143that is located outside the limiting groove1431. The first distance h1is less than the second distance h2. In this way, when one end of the conductive pillar130moves axially to the grounding bracket150in the high-speed running process of the rotor body110, the other end of the conductive pillar130is still located in the limiting groove1431and is not separated from the limiting groove1431. This reduces a distance by which the conductive pillar130moves axially, and ensures axial stability of the conductive pillar130. For example, when the first distance h1is zero, namely, when the step part133moves and abuts on the body part152of the grounding bracket150, the second distance h1is greater than zero, namely, the end of the conductive pillar130that faces the base143is still located in the limiting groove1431of the base143. Therefore, axial stability of the conductive pillar130is ensured, and radial stability of the conductive pillar130is also ensured. Still refer toFIG.4. A stop part132may extend from the outer wall of the conductive pillar130in a direction away from the axis. The conductive bearing120is located between the stop part132and the base143, and a distance between an end of the stop part132and the inner wall of the bearing housing140is less than a diameter of the steel ball122in the conductive bearing120. It should be noted that the distance between an end of the stopper132and the inner wall of the bearing housing140is a distance (shown by h3inFIG.3) between an end of the stop part132that is away from the axis of the conductive pillar130and the inner wall of the bearing housing140, where h3is less than the diameter of the steel ball122in the conductive bearing120. In this way, after the steel ball122in the conductive bearing120drops from the conductive bearing120, the steel ball122does not drop between the stop part132and the inner wall of the bearing housing140, to ensure that the steel ball122does not drop from the first end of the bearing housing140to the outside of the rotor body110. Refer toFIG.3. To facilitate assembling of the bearing housing140, a boss112may be formed on the inner wall of the shaft hole111, and an end of the bearing housing140that is away from the grounding bracket150abuts on the boss112. For example, the base143of the bearing housing140abuts on the boss112on the inner wall of the rotor body110, to further limit axial movement of the bearing housing140in the rotor body110. In addition, the boss112plays a role in quickly positioning assembling of the bearing housing140in the shaft hole111, namely, provided that the bearing housing140is placed downwards to abut on the boss112, positioning of the bearing housing140in the shaft hole111is completed. Refer toFIG.1andFIG.2. An embodiment of this application further provides a motor, including a motor housing200, a main bearing300, and the foregoing motor rotor100. The motor housing200is sleeved on an outer wall of the motor rotor100by using the main bearing300. In an embodiment, an inner ring of the main bearing300may interference fit with the outer wall of the motor rotor100, to ensure that the inner ring of the main bearing300is in closer contact with the motor rotor100, and ensure that the inner ring of the main bearing300and the motor rotor100are static relative to each other. Correspondingly, an outer ring of the main bearing300interference fits with an inner wall of the motor housing200, to ensure that the outer ring of the main bearing300is in closer contact with the motor housing200, and ensure that the outer ring of the main bearing300and the motor housing200are static relative to each other. In this embodiment of this application, the foregoing motor rotor100is disposed in the motor, to prevent the main bearing300of the motor rotor100from being electrically corroded by a shaft current. In addition, because no concentrated stress occurs in a conductive bearing120of the motor rotor100, and the conductive bearing120is not subject to offset loading force, the conductive bearing120is prevented from being abnormally worn. Therefore, conductive grease is prevented from overflowing because sealing rings on the conductive bearing120are worn, a service life of the conductive bearing120is prolonged, it is ensured that the shaft current on the motor rotor100is successfully discharged by using the conductive bearing120, and the main bearing300is not electrically corroded, to ensure that the motor runs normally. An embodiment of this application further provides a vehicle, including wheels and the foregoing motor. A motor rotor100of the motor is connected to the wheels to drive the wheels to rotate. For example, a rotation shaft of the motor rotor100may be connected to the wheels by using a transmission component, so that the rotation shaft of the motor rotates to output power, the transmission component transmits the power to the wheels, and therefore the wheels rotate. In this embodiment of this application, the foregoing motor is mounted on the vehicle, so that it is ensured that the motor of the vehicle can work stably, to stably drive the wheels. It should be noted that the vehicle in this embodiment of this application may include but is not limited to any one of an electric vehicle (EV), a battery electric vehicle (PEV/BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), or a new energy vehicle (new energy vehicle). In the descriptions of the embodiments of this application, it should be noted that, unless otherwise clearly specified and limited, terms “assemble”, “connected”, and “connection” should be understood in a broad sense. For example, the terms may be used for a fixed connection, an indirect connection through an intermediate medium, an internal connection between two elements, or an interaction relationship between two elements. Persons of ordinary skill in the art may understand specific meanings of the terms in the embodiments of this application based on specific cases. In the specification, claims, and accompanying drawings of the embodiments of this application, the terms “first”, “second”, “third”, “fourth”, and so on (if existent) are intended to distinguish between similar objects but do not necessarily indicate a specific order or sequence. | 59,460 |
11863030 | The following is description of the reference numerals inFIGS.1-7:100—a motor;200—first fan;300—second fan;1—stator assembly;11—stator core;111—stator yoke portion;1111—clamping slot;1112—through hole;112—stator tooth portion;1121—tooth surface;1122—limit step;1123—tooth body;121—first winding;122—second winding;21—first rotor assembly;211—first rotor disk;212—first permanent magnet;22—second rotor assembly;221—second rotor disk;2211—disk body exterior;2212—disk body interior;222—second permanent magnet;3—shaft sleeve;31—outer side wall;32inner side wall;33—flange;34—notch;35—trench;41—first rotating shaft assembly;411—first rotating shaft;4111—connecting section;4112—extending section;412—first rotational support;42—second rotating shaft assembly;421—second rotating shaft;422—second rotational support;51—first insulating frame;52—second insulating frame;6—mounting bracket;7—contact pin;8—casing;81—tooth wrapping surface;82—first circular boss;83—second circular boss;84—step surface;9—electric control plate;101—first shaft sleeve packaging cover;102—second shaft sleeve packaging cover;110—support bearing;131—first end packaging cover;132—second end packaging cover. The following is description of the reference numerals inFIGS.8-15:100′ motor;200′ first air fan;300′ second air fan;1′ a stator assembly;11′ stator core;111′ stator yoke portion;1111′ clamping slot;1112′ through hole;112′ stator tooth;1121′ tooth surface;1122′ limit step;1123′ tooth body;121′ first winding;122′ second winding;21′ first rotor assembly;211′ first rotor disk;212′ first permanent magnet;22′ second rotor assembly;221′ second rotor disk;2211′ disk body exterior;2212′ disk body interior;222′ second permanent magnet;31′ first rotating shaft assembly;311′ first rotating shaft;3111′ connecting section;3112′ extending section;312′ first rotational support;32′ second rotating shaft assembly;321′ second rotating shaft;322′ second rotational support;41′ first bearing cover;411′ outer wall;412′ inner wall;413′ flanging;414′ notch;42′ second bearing cover;51′ first insulating frame;52′ second insulating frame;6′ mounting bracket;7′ contact pin;8′ casing;81′ tooth wrapping surface;82′ first circular boss;83′ second circular boss;84′ step surface;9′ electric control plate;101′ a first end packaging cover;102′ a second end packaging cover;1021′ bearing chamber;1022′ annular groove; and110′ support bearing. DETAILED DESCRIPTION OF THE DISCLOSURE In order that the above objects, features and advantages of the present disclosure may be more clearly understood, the present disclosure is described in further detail below with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and the features in the embodiments herein may be combined with one another without conflict. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, the present disclosure may be practiced otherwise than as described herein. Therefore, the scope of the present disclosure is not limited to the specific embodiments disclosed below. A motor and a fan according to some embodiments of the present disclosure are described below with reference toFIGS.1-7. Embodiment 1 As shown inFIGS.1and2, an embodiment of the first aspect of the present disclosure provides a motor100including: a stator assembly1, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies. For example, the stator assembly1comprises a stator core11and two groups of mutually independent windings, as shown inFIG.2. A hollow channel is arranged in a radial middle part of the stator core11(as shown inFIGS.1,2,3and5), two axial end portions of the stator core11are provided with stator teeth protruding towards two axial sides of the stator core, as shown inFIG.2, and the two groups of windings are wound on two groups of stator teeth respectively. The two mutually independent rotor assemblies are oppositely and coaxially arranged on two axial sides of the stator assembly1and form an axial air gap with the stator assembly1. The two rotor assemblies are configured to rotate independently. The two mutually independent rotating shaft assemblies are coaxially connected with the two rotor assemblies respectively and protrude in a direction of the same side away from the stator core along the axial direction of the motor. Parts of the two rotating shaft assemblies are arranged in the hollow channel, as shown inFIGS.1and2. According to the motor100provided by the embodiment of the first aspect of the present disclosure, dual-power independent output of one motor100is realized by matching one stator assembly, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies, and two fans can be driven to independently rotate at respective rotating speeds and directions without interference. Compared with the solution that the two motors100are respectively connected with the two fans in a backward axial extension mode, in the present disclosure, at least one stator assembly1is omitted, the axial size of the fan is reduced, and the cost of the fan is reduced. Compared with the solution that a single-shaft motor100and a gear mechanism are matched to realize the shaft extension at both ends. In the present disclosure, the two fans rotate at any rotating speed and direction, the practical functionality is strong, the diversification of the fan functionality is remarkably improved, the gear mechanism is omitted, and the manufacturing and installation difficulty of products is reduced. The electric machine100comprises a stator assembly1, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies. The stator assembly1comprises a stator core11and two groups of mutually independent windings. Stator teeth are arranged at two axial ends of the stator core11, and the two groups of stator teeth protrude towards both sides along the axial direction of the stator core11and are wound by the two groups of windings, so that the two groups of windings can independently act on the motor100. A hollow channel is arranged at a radial middle part of the stator core11, providing an advantageous axial installation space for installation of the rotating shaft assemblies, so that parts of the two rotating shaft assemblies can be inserted into the hollow channel, and the axial size of the motor100is further shortened. The two rotor assemblies are oppositely and coaxially arranged on two axial sides of the stator assembly1, facing the two groups of windings respectively and forming an axial air gap with the stator assembly1, which ensures that the two rotor assemblies do not interfere with each other and have independent rotation. The two rotating shaft assemblies are independent from each other, are coaxially connected with the corresponding rotor assemblies respectively, and rotate synchronously with the corresponding rotor assemblies respectively. The two rotating shaft assemblies protrude towards the same axial side of the motor100, so that one axial end of the motor100can output two types of power which are not interfered with each other. Compared with the axial extension of the motor100at both sides, the axial distance of the output end of the motor100can be shortened. Because the two groups of windings of the stator assembly1are independent from each other, the two rotor assemblies are independent from each other, and the two rotating shaft assemblies are independent from each other, the two axial ends of the motor100can output two independent torques, which is equivalent to realizing the functions of the two independent motors100by using one motor100. Therefore, the present disclosure has the remarkable advantages of compact structure, strong practical functionality, convenient installation, small axial size and low manufacturing cost. The two rotor assemblies may be referred to as a first rotor assembly21and a second rotor assembly22, respectively, the shaft assembly connected to the first rotor assembly21being referred to as a first rotating shaft assembly41, the shaft assembly connected to the second rotor assembly22being referred to as a second rotating shaft assembly42, the winding cooperating with the first rotor assembly21being referred to as a first winding121, and the winding cooperating with the second rotor assembly22being referred to as a second winding122. The rotating shaft assembly comprises a rotating shaft, wherein the rotating shaft of one of the rotating shaft assemblies is a hollow shaft, as shown inFIG.1, and the rotating shaft of the other one of the rotating shaft assemblies extends out through the hollow shaft, as shown inFIGS.1and2, and is suitable for rotating relative to the hollow shaft. The rotating shaft assembly comprises a rotating shaft, the rotating shaft of one of the rotating shaft assemblies is a hollow shaft, and the rotating shaft of the other one of the rotating shaft assemblies can extend through the hollow shaft, so that the two rotating shaft assemblies protrude in the same direction, and one axial end of the motor100can be simultaneously connected with two fans or other components. Further, the shaft of the other shaft assembly is a solid shaft, which is advantageous for improving the strength of the shaft. Of course, the shaft of the other shaft assembly may also be a hollow shaft. The rotating shaft assembly in which the rotating shaft is a hollow shaft is referred to as the second rotating shaft assembly42, the rotating shaft of the second rotating shaft assembly42is referred to as the second rotating shaft421, and the rotating shaft of the first rotating shaft assembly41is referred to as the first rotating shaft411. For example, the first rotating shaft411is a solid shaft, as shown inFIG.1. Further, the rotating shaft of another one of the rotating shaft assemblies (i.e., the first rotating shaft assembly41) includes a connecting section4111and an extending section4112connected to the connecting section4111. As shown inFIG.1, the outer diameter of the connecting section4111is equal to the outer diameter of the hollow shaft, the connecting section4111and the hollow shaft are arranged along the axial direction of the hollow channel, and the extending section4112protrudes through the hollow shaft. The rotating shaft of another one of the rotating shaft assemblies comprises a connecting section4111and an extending section4112, the outer diameter of the connecting section4111is equal to the outer diameter of the hollow shaft, the connecting section4111and the hollow shaft are arranged along the axial direction of the hollow channel, and the outer contour of the parts in the hollow channel after the two rotating shafts are assembled is kept flush, so that the structure of the product is more regular, it is convenient for machine-shaping the product, and the assembly is also convenient. Meanwhile, a part (i.e., the connecting section4111) of the rotating shaft connected with the rotor assembly is relatively thick, the strength of the rotating shaft is improved, and the reliability of the rotating shaft is favorably improved; and the two rotating shafts are conveniently supported by supporting structures such as bearings and the like of the same type, so that the reliability and the stability of the motor100are improved. Further, as shown inFIGS.1,2,4and5, the motor100further comprises a shaft sleeve3provided in the hollow channel, and parts of the two rotating shaft assemblies are inserted into the shaft sleeve3. A shaft sleeve is arranged in the hollow channel3, ends of the two rotating shaft assemblies, at the same side of the rotating shaft assemblies, are inserted into the shaft sleeve3, the shaft sleeve3can play a good role in limiting the two rotating shaft assemblies, the mutual interference is avoided between the two rotating shaft assemblies and the stator assembly, and it reduces the probability that the rotating shaft assemblies shake, tilt, shift and the like. Therefore, the coaxiality of the two rotating shaft assemblies is improved, and the reliability of the motor100is improved. Meanwhile, the assembly precision of the rotating shaft assembly is improved, and the installation is more convenient. For example, the rotating shafts of the two rotating shaft assemblies can be nested, the first rotating shaft assembly41is inserted into the shaft sleeve3, and the other end protrudes towards one axial side of the motor100. The second rotating shaft assembly42is inserted into the shaft sleeve3, the other end of another one of the rotating shaft assemblies protrudes in the same axial side of the motor100through the rotating shaft assembly, and the two rotating shaft assemblies are respectively coaxially connected with the two rotor assemblies and synchronously rotate with the corresponding rotor assemblies. Further, as shown inFIG.1, the motor100further comprises a support bearing110coaxially provided between an output end of the hollow shaft and another one of the rotating shafts. The support bearing110is additionally arranged between an output end portion of the hollow shaft and another one of the rotating shafts, so that the support rigidity of the two rotating shaft assemblies can be further improved, and the reliability of the motor100is further improved. Further, the stator core11comprises a stator yoke portion111and a plurality of stator tooth portions112arranged along the circumferential direction of the stator yoke portion111. As shown inFIG.3, the stator core11is formed by assembling the stator tooth portions112and the stator yoke portion111, the stator tooth portions112protrude to two axial sides of the stator yoke portion111to form two groups of stator teeth, and the two groups of windings are wound on the stator teeth on the two axial sides of the stator yoke portion111respectively. According to the solution, the stator core11is divided into a stator yoke portion111and a plurality of stator tooth portions112, so that the processing difficulty of the stator core11is reduced, and the winding difficulty of two groups of windings is reduced. The stator yoke portion111can be formed by laminating a plurality of stator punching sheets, and the stator tooth portion112can also be formed by laminating a plurality of stator punching sheets. Of course, the stator core11may also be of unitary construction. Further, the radial middle part of the stator yoke portion111is provided with a through hole1112adapted to the shaft sleeve3of the motor100, and as shown inFIG.3, the through hole1112constitutes a part of the hollow channel of the stator core11. Due to the fact that the plurality of stator tooth portions112are arranged along the circumferential direction of the stator yoke portion111, a certain hollow space is enclosed by the plurality of stator tooth portions112. Thus, a through hole1112is formed in the radial middle part of the stator yoke portion111, the through hole1112and the hollow space form a hollow channel, which can provide an advantageous axial installation space for the rotating shaft assembly, and the axial size of the motor100is shortened. Further, a radial outer side wall of the stator yoke portion111is provided with a clamping slot1111, and as shown inFIG.3, a part of the stator tooth portion112is embedded into the clamping slot1111, so that the stator tooth portion112is in clamping fit with the stator yoke portion111. A clamping slot1111is formed in the radial outer side wall of the stator yoke portion111, and the stator tooth portion112can be clamped on the stator yoke portion by the clamping slot1111, so that the stator yoke portion111and the stator tooth portion112can be assembled. The structure is simple, and it is easy to process and assemble. Any one of the stator tooth portions112comprises at least one stator tooth, the stator tooth comprises a tooth body1123and a tooth surface1121connected with one axial end of the tooth body1123and located on one axial side of the stator yoke portion111, and all tooth surfaces1121of any one of the groups of stator teeth are located in a same plane and are perpendicular to the axis of the stator yoke portion111. Any one of the stator tooth portions112comprises at least one stator tooth, the stator tooth comprises a tooth body1123and a tooth surface1121, and the tooth surface1121is connected with an axial end, far away from the stator yoke portion111, of the tooth body1123and is positioned on the axial side of the stator yoke portion111; and all tooth surfaces1121of any set of stator teeth lie in the same plane and are perpendicular to the axis of the stator yoke portion111, ensuring that an axial air gap can be formed with the rotor assembly on that side. Further, the stator tooth portion112comprises two stator teeth, and a limit step1122is arranged on the tooth body1123of the stator tooth portion112and abuts against the stator yoke portion111for limiting axial movement of the stator tooth portion112with respect to the stator yoke portion111, as shown inFIG.3. One stator tooth portion112comprises two stator teeth, the tooth surfaces1121of the two stator teeth are respectively positioned on two axial sides of the stator yoke portion111, and an axial air gap can be formed with rotor assemblies on the two sides. Compared with the solution that one stator tooth112only comprises one stator tooth, the number of the stator teeth112is reduced, and the assembly process is simplified. Of course, one stator tooth112may also comprises only one stator tooth, and two opposing stator tooth portions112are installed at one position of the stator core11to form two stator teeth. Embodiment 2 The difference from Embodiment 1 is as follows: on the basis of Embodiment 1, further, as shown inFIG.6, the rotor assembly comprises a rotor disk coaxially connected with the rotating shaft assembly and a permanent magnet mounted on the rotor disk, and the rotor disk comprises a disk body exterior2211and a disk body interior2212connected with the disk body exterior2211from outside to inside in a radial direction of the rotor disk, wherein the disk body exterior2211is of a disk-shaped structure, and the disk body interior2212is of a disk-shaped structure or a cone-shaped structure. The rotor assembly comprises a rotor disk and a permanent magnet, and the rotor disk serves as a mounting carrier of the permanent magnet, achieving coaxial connection between the rotor assembly and the rotating shaft assembly; the permanent magnet is mounted on the rotor disk to generate a magnetic field that interacts with the stator assembly1. The disc body exterior of the rotor disk2211is of a disc-shaped structure, and the structure is regular, which facilitates processing and molding and arrangement of a plurality of permanent magnets; and the disc body exterior2212is of the disc-shaped structure or the conical structure, and the assembly structure of the rotor disk and the rotating shaft assembly can be reasonably designed according to the specific structure of the product, providing a favorable space for the installation of other parts. For example, the rotor disk and permanent magnet of the first rotor assembly21are referred to as a first rotor disk211and a first permanent magnet212, respectively, and the rotor disk and permanent magnet of the second rotor assembly22are referred to as a second rotor disk221and a second permanent magnet222, respectively. Further, the rotating shaft assembly comprises a rotating shaft, and the rotor disk is coaxially connected with the rotating shaft. The rotor disk and the rotating shaft are of an integrated structure formed by injection molding. Alternatively, the rotor disk and the rotating shaft are of an integrated structure formed by welding. Alternatively, the rotor disk is threadably connected with the rotating shaft. Alternatively, the rotor disk is in interference fit with the rotating shaft. The rotating shaft assembly comprises a rotating shaft, the rotor disk and the rotating shaft are coaxially connected and fixed together by injection molding or welding fabrication to form an integrated structure, or achieve a fixed connection by threaded connection, interference assembly and the like, so that the connection reliability of the rotating shaft and the rotor disk is effectively guaranteed, and the reliability of synchronous rotation of the rotating shaft and the rotor assembly is guaranteed. Of course, the rotating shaft may be fixedly connected with the rotor disk in other ways, such as by fasteners, etc. For example, the permanent magnet is of a circular or fan-shaped pie structure, the number of the permanent magnets is plural, and the plurality of permanent magnets are uniformly distributed on the axial surface of the rotor disk facing the stator yoke portion111circumferentially to form axial magnetic flux; and N poles and S poles of two adjacent permanent magnets are alternately arranged or are arranged in a Halbach array. The permanent magnets have a circular or fan-shaped pie structure, are arranged conveniently, reduce the axial size of the motor100, and are uniformly distributed on a surface, facing the stator yoke portion111, of the rotor disk along the circumferential direction of the rotor disk, so that axial magnetic flux is formed between the rotor assembly and the stator assembly1. N poles and S poles of the two adjacent permanent magnets can be alternately arranged or can be arranged in a Halbach array, and the N poles and the S poles of the two adjacent permanent magnets can be specifically adjusted according to product requirements. Embodiment 3 The difference from Embodiment 2 is as follows: on the basis of Embodiment 2, the rotating shaft assembly comprises a rotating shaft and a rotational support, wherein the rotational support is received in the shaft sleeve3and is positioned between the shaft sleeve3and the rotating shaft for supporting the rotating shaft and enabling the rotating shaft to be suitable for rotating relative to the shaft sleeve3, and the rotating shaft is coaxially connected with the rotor assembly. The rotating shaft assembly comprises a rotating shaft and a rotational support, and the rotational support is received in the shaft sleeve3and is positioned between the shaft sleeve3and the rotating shaft, which guarantees the stability of the position of the rotating shaft and the stability in the rotating process; and the rotating shaft is coaxially connected with the rotor assembly, so that the power output function of the motor100is realized. For example, the rotating shaft and the rotational support of the first rotating shaft assembly41are respectively referred to as a first rotating shaft411and a first rotational support412, and the rotating shaft and the rotational support of the second rotating shaft assembly42are respectively referred to as a second rotating shaft421and a second rotational support422. The rotating support comprises at least one bearing, as shown inFIGS.1and2. The rotational support comprises at least one bearing used for supporting the rotating shaft, so that the reliability of the rotating shaft can be remarkably improved. Of course, the rotational support is not limited to a bearing, and other structures are possible. For example, a plurality of roller pins are arranged on the inner side wall32of the shaft sleeve3along the circumferential direction, and the rotating shaft is supported by the plurality of roller pins; or a plurality of connecting rings are axially arranged on the inner side wall32of the shaft sleeve3, the inner side wall of each connecting ring is a smooth surface, and the rotating shaft is supported by the plurality of connecting rings. For example, the number of bearings is plural, and the plurality of bearings are distributed on the same axial side of the rotor assembly at intervals along the length direction of the rotating shaft, as shown inFIGS.1and2. A plurality of bearings are arranged at intervals along the length direction of the rotating shaft, so that a plurality of parts of the rotating shaft can be supported, the supporting reliability of the rotational support to the rotating shaft is improved, and the reliability of the rotating shaft assembly is further improved; and the plurality of bearings are located on the same axial side of the corresponding rotor assembly, so that the plurality of bearings are completely received in the shaft sleeve3conveniently. Therefore, the plurality of bearings are not matched with the end covers at both ends of the motor. As a result, efforts can be focused only on ensuring the machining precision of the shaft sleeve3, and the machining precision of the end covers does not need to be guaranteed, which is beneficial to reducing the manufacturing cost. Furthermore, the number of the bearings is two. The two bearings not only can effectively improve the supporting reliability of the rotating shaft assembly, but also can be conveniently received in the shaft sleeve3. The number of the parts is reduced, and the production cost is saved. Further, an outer side wall31of the shaft sleeve3is matched with the hollow channel, an inner side wall32of the shaft sleeve3is matched with the bearing, and the shaft sleeve3is matched with the hollow channel by a concave-convex structure to limit the axial movement of the shaft sleeve3relative to the stator assembly. The outer side wall31of the shaft sleeve3is matched with the hollow channel, and the inner side wall32of the shaft sleeve3is matched with the bearing to ensure the stability of the position of the shaft sleeve3; and the shaft sleeve3is matched with the hollow channel by the concave-convex structure, so that the shaft sleeve3can be prevented from moving axially relative to the stator assembly1, and the stability of the shaft sleeve3is further improved. For example, the concave-convex structure comprises a flange33(seeFIG.4) arranged on the outer side wall31of the shaft sleeve3and a groove arranged on the wall surface of the hollow channel; wherein, the flange33is further provided with at least one notch34, as shown inFIG.4. The flange33is arranged on the outer side wall31of the shaft sleeve3, and a groove is correspondingly arranged on the wall surface of the hollow channel. When the flange33is embedded into the groove during assembly, assembly positioning of the shaft sleeve3can be realized, and the axial movement of the shaft sleeve3is limited along the stator assembly1. The flange33is further provided with at least one notch34, and the notch34can be in concave-convex fit with the casing subjected to later injection molding, so that the shaft sleeve3is prevented from rotating circumferentially relative to the stator assembly1, and the stability of the shaft sleeve3is further improved. Further, the number of the notches34is plural, and the plurality of the notches34are distributed at intervals along the circumferential direction of the flange33. Further, a separation portion is provided on the inner side wall32of the shaft sleeve3for separating the two rotational supports at intervals. The separation portion is arranged on the inner side wall32of the shaft sleeve3, and the rotational supports of the two rotating shaft assemblies can be separated at intervals by the separation portion, so that the two rotating shaft assemblies are effectively prevented from interfering with each other, and the reliability of the two rotating shaft assemblies is further improved. For example, the separation portion is a trench35(shown inFIG.4) for installing an annular retaining ring or a baffle; and the separation portion may also be an annular protrusion or an integrally formed partition. Embodiment 4 The difference from Embodiment 3 is as follows: on the basis of Embodiment 3, the motor100further comprises an insulating frame, a mounting bracket6and a plurality of pins7, as shown inFIGS.1and2. For example, the insulating frame is mounted on the stator teeth; the mounting bracket6is fixedly connected to the insulating frame; a plurality of contact pins7are inserted to the mounting bracket6, wherein lead-out wires of the two groups of windings are fixedly connected to the plurality of contact pins7. The motor100further comprises an insulating frame, a mounting bracket6and a plurality of contact pins7, and the insulating frame is mounted on the stator teeth, which guarantees the safety and reliability of the windings mounted on the stator teeth. The mounting bracket6is fixedly connected with the insulating frame, a plurality of contact pins7are inserted into the mounting bracket, lead-out wires of the two groups of windings are fixedly connected to the plurality of contact pins7, and accordingly the lead-out wire heads of the two groups of windings are led to a fixed and stable conductive carrier. The number of the insulating frames is two or two groups, the two or two groups of the insulating frames are respectively mounted on two groups of stator teeth and are respectively referred to as a first insulating frame51and a second insulating frame52, and the mounting bracket6is fixedly connected with one of the insulating frames. For example, the mounting bracket6is of an arc-shaped strip structure coaxial with the stator assembly1, and the mounting bracket6and the plurality of contact pins7are located on the radial outer side of the rotor assembly, as shown inFIG.5. The mounting bracket6is of an arc-shaped strip structure coaxial with the stator assembly1, and the mounting bracket6and the plurality of contact pins7are located on the radial outer side of the rotor assembly, so that the structure of the motor100is relatively regular, the internal magnetic field of the motor100cannot be easily interfered, and meanwhile the motor is convenient to be connected with an external circuit. Further, the motor100further comprises a casing8, as shown inFIG.2, which is an injection molded body and fixedly connects the insulating frame, the mounting bracket6, the plurality of contact pins7and the shaft sleeve3to one another to provide an integrated structure, as shown inFIG.2, wherein, an outer diameter of the casing8is greater than the maximum radial outer contour surface formed by the stator assembly1, the insulating frame, the mounting bracket6, the plurality of contact pins7; and two axial end faces of the casing8comprises an inner end face and an outer end face connected with an outer edge of the inner end face, and the outer end face is located on the radial outer side of the inner end face and at least partially protrudes out of the inner end face, so that the two axial end faces of the casing8form a stepped structure with high outer height and low inner height, wherein the two inner end faces are flush with the two axial end faces of the stator core11or do not exceed the two axial end faces of the stator core11. The motor100further comprises a casing8, wherein the casing is an injection molded body for coating the insulating frame, the mounting bracket6and other structures, so that the insulating frame, the mounting bracket6, the plurality of contact pins7and the shaft sleeve3can be fixedly connected to form a whole, and the stability of the motor100is guaranteed; and the outer diameter of the casing8is greater than the maximum radial outer contour surface formed by the stator assembly1, the insulating frame, the mounting bracket6and the plurality of contact pins7, so that the components are coated in the radial outer surface of the casing8, and it guarantees the integrity and the regularity of the appearance of the motor100and the insulation between the motor and the outside. Meanwhile, the two axial end faces (which can also be called tooth wrapping surfaces81) of the casing8are not regular planes, but are stepped structures with high outer height and low inner height and low outside, as shown inFIGS.2and5, and a portion which is located radially outside and protrudes is referred to as an outer end face which is relatively small in size; and a portion recessed on the inside is referred to as an inner end face which is relatively large in size, as shown inFIGS.2and5. The two inner end faces (i.e., the two axial end faces on the radial inner side of the casing8) are flush with the two axial end faces of the stator core11or do not exceed the two axial end faces of the stator core11(i.e., the two groups of tooth surfaces1121of the stator core11), so that the axial air gap between the tooth surfaces and the permanent magnet can be controlled more accurately and effectively. Further, two outer end faces of the casing8are respectively provided with a circular boss coaxial with the stator assembly1, as shown inFIG.5. Two circular bosses are arranged on the two outer end faces of the casing8(i.e., two axial end faces on the radial outer side of the casing8) and are coaxially connected with the stator assembly1, so that the casing can be conveniently matched with other structures to package the motor100. Further, avoidance notches may be provided on the circular boss to facilitate assembly or commissioning of the motor100. Here, a circular boss located on one side of the first rotor assembly21is referred to as a first circular boss82, and a circular boss located on one side of the second rotor assembly22is referred to as a second circular boss83. Further, a step surface84is provided at a position, close to an axial end of the plurality of contact pins7, of the casing8, and the plurality of contact pins7pass through the step surface84and protrude out of the step surface84along the axial direction of the stator assembly1, as shown inFIG.5. A step surface84is arranged at a position, close to an axial end of the plurality of contact pins7, of the casing8, so that the plurality of contact pins7pass through the step surface84and protrude out of the step surface84along the axial direction of the stator assembly1, which can provide an advantageous space for connection or installation of the contact pins and other conductive parts. Here, the step surface84can be arranged on the inner side wall of one of the circular bosses, so that the casing structure is further simplified. Further, as shown inFIGS.1and2, the motor100further comprises two end packaging covers which are coaxially and fixedly arranged at the two axial ends of the casing8respectively for packaging the motor100and are provided with shaft holes for extending out the two rotating shaft assemblies. The end packaging covers are arranged at the two axial ends of the casing8, so that the integrity of the motor is100guaranteed, and the internal structure of the motor100is effectively protected; and the end packaging cover is provided with a shaft hole for allowing the corresponding rotating shaft to extend out, so that the power of the motor100can be output. A step is formed between the outer wall surface of the circular boss and the outer wall surface of the casing8, and the end packaging cover can be provided with a cover edge which is just matched with the step, so that the outer contour of the motor100is regular. Among them, an end packaging cover located on one side of the first rotor assembly21is referred to as a first end packaging cover131, and an end packaging cover located on one side of the second rotor assembly22is referred to as a second end packaging cover132. Further, as shown inFIGS.1and2, the motor100further comprises an electric control plate9internally arranged between the rotor assembly on any side of the motor100and the end packaging cover. Due to the arrangement of the electric control plate9, automatic control of the motor100is facilitated; and the electric control plate9is arranged on any side of the motor100and positioned between the rotor assembly on the side and the end packaging cover, so that the stability of the electric control plate9is guaranteed, and the circuit output of the electric control plate9is facilitated. Further, as shown inFIG.2, the motor100further comprises two shaft sleeve packaging covers which are fixedly connected at axial ports of the shaft sleeves3for limiting the axial movement of the rotating shaft assemblies. The shaft sleeve packaging covers are arranged at the two axial ports of the shaft sleeve3, so that the axial movement of the rotational support in the shaft sleeve3can be prevented, the axial movement of the two rotating shaft assemblies is limited, and the reliability of the motor100is further improved. The sleeve packaging cover can be fixedly connected with the sleeve3via fasteners such as screws and the like. The shaft sleeve packaging cover located on one side of the first rotor assembly21is referred to as a first shaft sleeve packaging cover101, and the shaft sleeve packaging cover located on one side of the second rotor assembly22is referred to as a second shaft sleeve packaging cover102. As shown inFIG.7, an embodiment of the second aspect of the present disclosure provides a fan, comprising: at least one motor100according to any one of the embodiments of the first aspect; and two fans fixedly connected with the two rotating shaft assemblies of the motor100respectively, wherein the two fans rotate coaxially and independently. Due to the fact that the fan provided by the embodiment of the second aspect of t the present disclosure comprises the motor100in any one of the embodiments of the first aspect, the fan has the remarkable advantages of compact structure, strong practical functionality, convenient installation, small axial size, low manufacturing cost and the like. Here, a fan connected with the first rotating shaft assembly41is referred to as a first fan200, and a fan connected with the second rotating shaft assembly42is referred to as a second fan300. In this description, the extension direction of the central axis inFIG.1is simply referred to as “axial direction”, the direction around the central axis is simply referred to as “circumferential direction”, and the direction perpendicular to the central axis is simply referred to as “radial direction”. The motor100and the fan provided by the present disclosure are described below in connection with a specific example. As shown inFIGS.1to7, a motor100includes a stator assembly1, two rotor assemblies (i.e., a first rotor assembly21and a second rotor assembly22), a shaft sleeve3, and two shaft assemblies (i.e., a first rotating shaft assembly41and a second rotating shaft assembly42). In particular, the stator assembly1comprises a stator core11and two groups of windings (i.e., a first winding121and a second winding122), the stator core11is connected by a stator yoke portion111and a plurality of removable stator teeth112into a radially hollow integral body with axially extending teeth, and the stator radial hollow provides an advantageous axial mounting space for the bearings of the motor100. The first winding121and the second winding122are respectively wound on the stator tooth bodies1123on the two axial sides of the stator, and the first winding121and the second winding122can act independently of each other on the motor100. A plurality of rabbets (i.e., clamping slots1111) are formed on the radial outer side of the stator yoke portion111and used for matching and installation of the stator tooth portion112; and a circular hole groove (i.e., a through hole1112) is formed on the radial inner side of the stator yoke portion111for mounting the shaft sleeve3. The single stator tooth portion112is provided with at least one tooth body1123and at least one tooth surface1121. After the plurality of stator tooth portions112are matched and installed with the stator yoke portion111, two groups of tooth bodies1123and two groups of tooth surfaces1121are arranged on the two axial sides of the stator yoke portion111, and one group of tooth surfaces1121which act with the same rotor assembly are in one plane and perpendicular to the axis; and a limit step1122is provided on a surface on which the stator tooth portion112is matched and installed with the stator yoke portion111for abutting against an axial end face of the stator yoke portion111to define an axial relative position of the stator tooth portion112and the stator yoke portion111. The first rotor assembly21and the second rotor assembly22are oppositely and coaxially disposed axially outsides two axial sides of the stator assembly1to form an axial air gap with the stator assembly1. The first rotor assembly21comprises a first rotor disk211and a first permanent magnet212, the second rotor assembly22comprises a second rotor disk221and a second permanent magnet222, and the first rotor assembly21and the second rotor assembly22are rotatable independently of each other. The first rotor disk211and the second rotor disk221are generally identical in structure, and one of the rotor disks is illustrated as an example. The radial outer side of the rotor disk is of a disc-shaped structure, and the radial inner side of the rotor disk is of a disc-shaped plane or conical inclined plane structure, providing a favorable space for installation of other parts. The radial outer side of the first rotor disk211is of a disc-shaped structure and is fixedly connected with the first rotating shaft411in a threaded connection mode; and the radial outer side of the second rotor disk221is of a disc-shaped structure and is fixedly connected with the second rotating shaft421by injection molding. The first permanent magnet212and the second permanent magnet222are of a circular or fan-shaped pie structure and are uniformly distributed on the axial surface of the rotor disk disc-shaped structure in the circumferential direction to form axial magnetic flux; and N and S poles of two adjacent permanent magnets are alternately arranged or arranged in a Halbach array. The shaft sleeve3is positioned in the hollow of the stator core11and coaxially fixed and extends out of the two axial sides of the stator yoke portion111. The outer wall of the shaft sleeve3is matched with a circular groove hole, at the radial inner side, of the stator yoke portion111, the inner wall of the shaft sleeve3is matched with a bearing of the first rotating shaft assembly41and the second rotating shaft assembly42, a flange33is provided on the radial outer side of the shaft sleeve3for limiting the axial direction of the stator yoke portion111, and a plurality of small notches34are uniformly distributed in the radial direction of the flange33for stopping rotation and connection. A trench35is formed in the middle of the inner wall of the sleeve3for mounting the retaining ring to space the first rotational support412and the second rotational support422of the two rotating shaft assemblies. The first rotating shaft assembly41and the second rotating shaft assembly42are coaxially and fixedly connected with the first rotor assembly21and the second rotor assembly22, respectively, and output coaxially from the same axial side of the motor100. The first rotating shaft assembly41and the second rotating shaft assembly42can rotate independently of each other. The first rotating shaft assembly41comprises a solid shaft and two bearings, wherein the two bearings are coaxially arranged on the radial outer side of the solid shaft and are axially spaced on the same axial side of the solid shaft which is fixedly connected with the first rotor assembly to form a first rotational support412. The second rotating shaft assembly42comprises a hollow shaft and two bearings coaxially provided at the radial outer side of the hollow shaft and axially spaced on the same axial side of the hollow shaft which is fixedly connected with the first rotor assembly to form a second rotational support422. The first rotational support412of the first rotating shaft assembly41and the second rotational support422of the second rotating shaft assembly42are disposed at the two axial sides of the motor100, and are all received in the shaft sleeve3. The motor100further comprises a first insulating frame51and a second insulating frame52mounted on the tooth body1123of the stator tooth, a mounting bracket6fixedly connected to the first insulating frame51or the second insulating frame52, and a plurality of contact pins7inserted on the mounting bracket6. Lead-out wires of the first winding121and the second winding122are each fixedly connected to the plurality of contact pins7, so that the lead-out wires of the first winding121and the second winding122are led out to a fixed and stable conductive carrier. The mounting bracket6is of an arc-shaped strip structure coaxial with the stator, and the mounting bracket6and the plurality of contact pins7are located on the radial outer sides of the first rotor assembly21and the second rotor assembly22. The motor100further comprises a plastic casing8fixedly connecting the stator assembly1, the first insulating frame51and the second insulating frame52, the mounting bracket6, the plurality of contact pins7and the shaft sleeve3to one another to provide an integrated structure. The outer diameter of the plastic casing8is greater than the maximum radial outer contour surface formed collectively by the stator assembly1, the first insulating frame51, the second insulating frame52, the mounting bracket6and the plurality of contact pins7. The wrapping surfaces (i.e., the two axial end faces of the casing8) of the stator tooth portions112on the two axial sides are flush or do not exceed the two groups of tooth surfaces1121of the stator assembly1. Two cylindrical bosses (i.e., circular bosses) coaxial with the stator assembly1are provided on the outer sides of the two axial ends of the plastic casing8; and the plastic casing8is provided with a step surface84on the side where the contact pin7is located, and the contact pin7is exposed out of the step surface84by a certain distance, so that a space is provided for connecting or installing the contact pin7with other conductive parts. The motor100further comprises a first sleeve packaging cover101and a second sleeve packaging cover102, and the first sleeve packaging cover101and the second sleeve packaging cover102are fixedly connected at a port of the sleeve3and define the axial movement of the first rotating shaft assembly41and the second rotating shaft assembly42. The motor100further comprises a first end packaging cover131and a second end packaging cover132. The first end packaging cover131and the second end packaging cover132are coaxially and fixedly mounted at the two axial ends of the plastic casing8respectively and are used for packaging the motor100, and the end packaging cover is matched with the plastic casing8via a spigot. The motor100may further comprise an electric control plate9interposed between the first rotor assembly21and the first end packaging cover131or between the second rotor assembly22and the second end packaging cover132on either side of the motor100. The motor100may further comprise a support bearing110coaxially provided between the output end of the hollow shaft and the solid shaft for increasing the support strength of the first rotating shaft assembly41and the second rotating shaft assembly42. An electrical fan comprises a motor100, a first fan200, and a second fan300. The first fan200and the second fan300are coaxially and fixedly connected with the first rotating shaft assembly41and the second rotating shaft assembly42respectively, and output on the same side of the motor100. The first fan200and the second fan300rotate coaxially and independently. Therefore, the motor and the fan have the remarkable advantages of compact structure, strong practical functionality, convenient installation, small axial size, low manufacturing cost and the like. The motor and the fan according to some embodiments of the present disclosure are described below with reference toFIGS.8-15. Embodiment 1 As shown inFIGS.8and9, an embodiment of the first aspect of the present disclosure provides a motor100′ including: a stator assembly1′, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies. For example, the stator assembly1′ comprises a stator core11′ and two groups of mutually independent windings; a hollow channel is arranged in a radial middle part of the stator core11′, as shown inFIG.9, two axial end portions of the stator core11′ are provided with stator teeth protruding towards two axial sides of the stator core, as shown inFIG.10, and the two groups of windings are wound on the two groups of stator teeth respectively; two mutually independent rotor assemblies are oppositely and coaxially arranged on two axial sides of the stator assembly1′ and form an axial air gap with the stator assembly1′, and the two rotor assemblies are configured to rotate independently; and two mutually independent rotating shaft assemblies which comprise a rotating shaft and a rotational support, wherein the rotational support is at least partially received in the hollow channel and sleeved on the rotating shaft and is used for supporting the rotating shaft and enabling the rotating shaft to rotate relative to the stator core11′, and the two rotating shafts are respectively coaxially connected with the two rotor assemblies and protrude in a direction of the same side away from the stator core11′ along the axial direction of the motor100′, as shown inFIGS.8and9. According to the motor100′ provided by the embodiment of the first aspect of the present disclosure, dual-power independent output of one motor100′ is realized by matching one stator assembly, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies, and two fans can be driven to independently rotate at respective rotating speeds and directions without interference. Compared with the solution that the two motors100′ are respectively connected with the two fans in a backward axial extension mode, in the present disclosure, at least one stator assembly1′ is omitted, the axial size of the fan is reduced, and the cost of the fan is reduced. Compared with the solution that a single-shaft motor100′ and a gear mechanism are matched to realize the shaft extension at both ends, in the present disclosure, the two fans rotate at any rotating speed and direction, the practical functionality is strong, the diversification of the fan functionality is remarkably improved, the gear mechanism is omitted, and the manufacturing and installation difficulty of products is reduced. In particular, the electric machine100′ comprises a stator assembly1′, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies. The stator assembly1′ comprises a stator core11′ and two groups of mutually independent windings. Stator teeth are arranged at two axial ends of the stator core11′, and the two groups of stator teeth protrude towards both sides along the axial direction of the stator core11′ and are wound by the two groups of windings, so that the two groups of windings can independently act on the motor100′. A hollow channel is arranged at a radial middle part of the stator core11′, providing an advantageous axial installation space for installation of the rotating shaft assemblies, so that parts of the two rotating shaft assemblies can be inserted into the hollow channel, and the axial size of the motor100′ is further shortened. The two rotor assemblies are oppositely and coaxially arranged on two axial sides of the stator assembly1′, face the two groups of windings respectively, and form an axial air gap with the stator assembly1′, which ensures that the two rotor assemblies do not interfere with each other and have independent rotation. The rotating shaft assembly comprises a rotating shaft and a rotational support, wherein the rotational support is partially or completely received in the hollow channel and is sleeved on the rotating shaft, which guarantees the stability of the position of the rotating shaft and the stability in the rotating process; and the rotating shaft is coaxially connected with the rotor assembly, so that the power output function of the motor100′ is realized. The two rotating shaft assemblies are independent from each other, are coaxially connected with the corresponding rotor assemblies respectively, and rotate synchronously with the corresponding rotor assemblies respectively. The two rotating shaft assemblies protrude towards the same axial side of the motor100′, so that one axial end of the motor100′ can output two types of power which are not interfered with each other. Compared with the axial extension of the motor100′ at both sides, the axial distance of the output end of the motor100′ can be shortened. Because the two groups of windings of the stator assembly1are independent from each other, the two rotor assemblies are independent from each other, and the two rotating shaft assemblies are independent from each other, the two axial ends of the motor100′ can output two independent torques, which is equivalent to realizing the functions of the two independent motors100′ by using one motor100′. Therefore, the present disclosure has the remarkable advantages of compact structure, strong practical functionality, convenient installation, small axial size and low manufacturing cost. The two rotor assemblies may be referred to as a first rotor assembly21′ and a second rotor assembly22′, respectively, the shaft assembly connected to the first rotor assembly21′ being referred to as a first rotating shaft assembly31′, the shaft assembly connected to the second rotor assembly22′ being referred to as a second rotating shaft assembly32′, the winding cooperating with the first rotor assembly21being referred to as a first winding121′, and the winding cooperating with the second rotor assembly22′ being referred to as a second winding122′. For example, the rotating shaft and the rotational support of the first rotating shaft assembly31′ are respectively referred to as a first rotating shaft311′ and a first rotational support312′, and the rotating shaft and the rotational support of the second rotating shaft assembly32′ are respectively referred to as a second rotating shaft321′ and a second rotational support322′. The rotating support comprises at least one bearing, as shown inFIGS.8and9. The rotational support comprises at least one bearing used for supporting the rotating shaft, so that the reliability of the rotating shaft can be remarkably improved. Of course, the rotational support is not limited to a bearing, and other structures are possible. For example, a plurality of roller pins are arranged on the inner side wall of the hollow channel along the circumferential direction, and the rotating shaft is supported by the plurality of roller pins; or a plurality of connecting rings are axially arranged on the inner side wall of the hollow channel, the inner side wall of each connecting ring is a smooth surface, and the rotating shaft is supported by the plurality of connecting rings. For example, the number of bearings is plural, and the plurality of bearings are distributed on the two axial sides of the rotor assembly at intervals along the length direction of the rotating shaft, as shown inFIGS.8and9. A plurality of bearings are arranged at intervals along the length direction of the rotating shaft, so that a plurality of parts of the rotating shaft can be supported, the supporting reliability of the rotational support to the rotating shaft is improved, and the reliability of the rotating shaft assembly is further improved; and a plurality of bearings are located on the two axial sides of the corresponding rotor assembly, so that a plurality of positions of the rotating shaft can be supported dispersedly, the supporting reliability of the rotating shaft is improved, the risk that the rotating shaft inclines and the like is obviously reduced, and the using reliability of the motor100′ is improved. Furthermore, the number of the bearings is two, as shown inFIGS.8and9. The two bearings not only can effectively improve the supporting reliability of the rotating shaft assembly, but also can reduce the number of components and save the production cost. Further, as shown inFIGS.8and9, the motor100′ further comprises two bearing covers sleeved in the hollow channel and fixedly connected with the stator core11′. The two bearing covers are arranged opposite to each other for respectively supporting the bearings axially inwards of the corresponding rotating shaft assemblies. The two bearing covers are arranged in the hollow channel to support the bearings axially inwards of the two rotating shaft assemblies (i.e., the bearings relatively close to the interior of the motor100′). Because the two bearing covers are arranged opposite to each other, the two rotational supports can be well limited, so that the two rotating shaft assemblies and the stator assembly do not interfere each other, and the probability that the rotating shaft assemblies shake, tilt, shift and the like is reduced; and the reliability of the motor100′ is improved, the assembly precision of the rotating shaft assembly is improved, and the installation is more convenient. In addition, the two bearing covers can play a role of a separator, and the rotational supports of the two rotating shaft assemblies are separated at intervals, so that the two rotating shaft assemblies are effectively prevented from interfering with each other, and the reliability of the two rotating shaft assemblies is further improved. Here, the bearing cover corresponding to the first rotating shaft assembly31′ is referred to as a first bearing cover41′, and the bearing cover corresponding to the second rotating shaft assembly32′ is referred to as a second bearing cover42′. Further, the bearing cover is adapted to the shape of the bearing, as shown inFIGS.9and11, and the bearing is received in the bearing cover and supported by the bearing cover, as shown inFIG.8. The bearing covers are adapted to the forms of the bearings, so that the bearings axially inwards of the two rotating shaft assemblies can sink into the bearing covers, achieving effective support and limit, and the reliability of the motor100′ is further improved. Further, an open end of the bearing cover is provided with a flanging413′ extending radially outwards, as shown inFIG.11. The open end of the bearing cover is provided with the flanging413′, the flanging413′ extends radially outwards and can be in concave-convex fit with the casing8′ subjected to later injection molding, achieving a certain limiting effect, and the bearing cover is prevented from moving axially relative to the stator core11′. Further, the flange413′ is provided with at least one notch414′, as shown inFIG.11. The flanging413′ is provided with at least one notch414′ which can be in concave-convex fit with the casing8′ subjected to later injection molding, so that the bearing cover is prevented from rotating circumferentially relative to the stator assembly1′, and the stability of the bearing cover is further improved. Further, the number of the notches414′ is plural, and the plurality of notches414′ are distributed at intervals along the circumferential direction of the flanging413′. Further, the rotating shaft of one of the shaft assemblies is a hollow shaft, as shown inFIG.8, and the shaft of the other shaft assembly extends out through the hollow shaft, as shown inFIGS.8and9, and is suitable for rotating relative to the hollow shaft. The rotating shaft of one of the rotating shaft assemblies is a hollow shaft, and the rotating shaft of the other one of the rotating shaft assemblies can extend through the hollow shaft, so that the two rotating shaft assemblies protrude in the same direction, and one axial end of the motor100′ can be simultaneously connected with two fans or other components. In particular, the shaft of the other shaft assembly is a solid shaft, which is advantageous for improving the strength of the shaft. Of course, the shaft of the other shaft assembly may also be a hollow shaft. For example, the rotating shaft assembly in which the rotating shaft is a hollow shaft is referred to as the second rotating shaft assembly32′, the rotating shaft of the second rotating shaft assembly32′ is referred to as the second rotating shaft321′, and the rotating shaft of the first rotating shaft assembly31′ is referred to as the first rotating shaft311′. For example, the first rotating shaft311′ is a solid shaft, as shown inFIG.8. Further, the rotating shaft of the other one of the rotating shaft assemblies (i.e., the first rotating shaft assembly31′) includes a connecting section3111′ and an extending section3112′ connected to the connecting section3111′. As shown inFIG.8, the outer diameter of the connecting section3111is equal to the outer diameter of the hollow shaft, the connecting section3111′ and the hollow shaft are arranged along the axial direction of the hollow channel, and the extending section3112′ protrudes through the hollow shaft. The rotating shaft of the other one of the rotating shaft assemblies comprises a connecting section3111′ and an extending section3112′, the outer diameter of the connecting section3111′ is equal to the outer diameter of the hollow shaft, the connecting section3111′ and the hollow shaft are arranged along the axial direction of the hollow channel, and the outer contour of the parts in the hollow channel after the two rotating shafts are assembled is kept flush, so that the structure of the product is more regular, it is convenient for machine-shaping the product, and the assembly is also convenient. Meanwhile, a part (i.e., the connecting section3111′) of the rotating shaft connected with the rotor assembly is relatively thick, the strength of the rotating shaft is improved, and the reliability of the rotating shaft is favorably improved; and the two rotating shafts are conveniently supported by supporting structures such as bearings and the like of the same type, so that the reliability and the stability of the motor100′ are improved. Further, as shown inFIG.8, the motor100′ further comprises a support bearing110′ coaxially provided between an output end of the hollow shaft and the other one of the rotating shafts. A support bearing110′ is additionally arranged between an output end portion of the hollow shaft and the other one of the rotating shafts, so that the support rigidity of the two rotating shaft assemblies can be further improved, and the reliability of the motor100′ is further improved. Further, the stator core11′ comprises a stator yoke portion111′ and a plurality of stator tooth portions112′ arranged along the circumferential direction of the stator yoke portion111′. As shown inFIG.10, the stator core11′ is formed by assembling the stator tooth portions112′ and the stator yoke portion111′, the stator tooth portions112′ protrude to two axial sides of the stator yoke portion111′ to form two groups of stator teeth, and the two groups of windings are wound on the stator teeth on the two axial sides of the stator yoke portion111′ respectively. According to the solution, the stator core11′ is divided into a stator yoke portion111′ and a plurality of stator tooth portions112′, so that the processing difficulty of the stator core11′ is reduced, and the winding difficulty of two groups of windings is reduced. The stator yoke portion111′ can be formed by laminating a plurality of stator punching sheets, and the stator tooth portion112′ can also be formed by laminating a plurality of stator punching sheets. Of course, the stator core11′ may also be of unitary construction. Further, a radial middle portion of the stator yoke portion111′ is provided with a through hole1112′ adapted to the bearing cover of the motor100′, which forms a part of the hollow channel of the stator core11′, as shown inFIG.10, the radial middle part of the stator yoke portion111′ is provided with a through hole1112′ adapted to the bearing cover of the motor100′, and as shown inFIG.10, the through hole1112′ constitutes a part of the hollow channel of the stator core11′. Due to the fact that the plurality of stator tooth portions112′ are arranged along the circumferential direction of the stator yoke portion111′, a certain hollow space is enclosed by the plurality of stator tooth portions112′. Thus, a through hole1112′ is formed in the radial middle part of the stator yoke portion111′, the through hole1112′ and the hollow space form a hollow channel, which can provide an advantageous axial installation space for the rotating shaft assembly, and the axial size of the motor100′ is shortened. Further, a radial outer side wall of the stator yoke portion111′ is provided with a clamping slot1111′, and as shown inFIG.10′, a part of the stator tooth portion112′ is embedded into the clamping slot1111′, so that the stator tooth portion112′ is in clamping fit with the stator yoke portion111′. A clamping slot1111′ is formed in the radial outer side wall of the stator yoke portion111′, and the stator tooth portion112′ can be clamped on the stator yoke portion by the clamping slot1111′, so that the stator yoke portion111′ and the stator tooth portion112′ can be assembled. The structure is simple, and it is easy to process and assemble. Each of the stator tooth portions112′ comprises at least one stator tooth. The stator tooth comprises a tooth body1123′ and a tooth surface1121′ connected with one axial end of the tooth body1123′ and located on one axial side of the stator yoke portion111′. All tooth surfaces1121′ of any one of the groups of stator teeth are located in a same plane and are perpendicular to the axis of the stator yoke portion111′. Each of the stator tooth portions112′ comprises at least one stator tooth. The stator tooth comprises a tooth body1123′ and a tooth surface1121′, and the tooth surface1121′ is connected with an axial end, far away from the stator yoke portion111′, of the tooth body1123′ and is positioned on the axial side of the stator yoke portion111′. All tooth surfaces1121′ of any set of stator teeth lie in the same plane and are perpendicular to the axis of the stator yoke portion111′, ensuring that an axial air gap can be formed with the rotor assembly on that side. Further, the stator tooth portion112′ comprises two stator teeth, and a limit step1122′ is arranged on the tooth body1123′ of the stator tooth portion112′ and abuts against the stator yoke portion111′ for limiting axial movement of the stator tooth portion112′ with respect to the stator yoke portion111′, as shown inFIG.10. One stator tooth portion112′ comprises two stator teeth, the tooth surfaces1121′ of the two stator teeth are respectively positioned on two axial sides of the stator yoke portion111′, and an axial air gap can be formed with rotor assemblies on the two sides. Compared with the solution that one stator tooth112′ only comprises one stator tooth, the number of the stator teeth112′ is reduced, and the assembly process is simplified. Of course, one stator tooth112′ may also comprises only one stator tooth, and two opposing stator tooth portions112′ are installed at one position of the stator core11′ to form two stator teeth. Embodiment 2 The difference from Embodiment 1 is as follows: on the basis of Embodiment 1, further, as shown inFIG.14, the rotor assembly comprises a rotor disk coaxially connected with a corresponding rotating shaft and a permanent magnet mounted on the rotor disk, and the rotor disk comprises a disk body exterior2211′ and a disk body interior2212′ connected with the disk body exterior2211′ from outside to inside in a radial direction of the rotor disk, wherein the disk body exterior2211′ is of a disk-shaped structure, and the disc interior2212′ is of a disc-shaped structure or a cone-shaped structure. The rotor assembly comprises a rotor disk and a permanent magnet, and the rotor disk serves as a mounting carrier of the permanent magnet, achieving coaxial connection between the rotor assembly and the rotating shaft; the permanent magnet is mounted on the rotor disk to generate a magnetic field that interacts with the stator assembly1′. The disc body exterior of the rotor disk2211′ is of a disc-shaped structure, and the structure is regular, which facilitates processing and molding and arrangement of a plurality of permanent magnets; and the disc body exterior2212′ is of the disc-shaped structure or the conical structure, and the assembly structure of the rotor disk and the rotating shaft assembly can be reasonably designed according to the specific structure of the product, providing a favorable space for the installation of other parts. For example, the rotor disk and permanent magnet of the first rotor assembly21′ are referred to as a first rotor disk211′ and a first permanent magnet212′, respectively, and the rotor disk and permanent magnet of the second rotor assembly22′ are referred to as a second rotor disk221′ and a second permanent magnet222′, respectively′. The rotor disk and the rotating shaft are of an integrated structure formed by injection molding. Alternatively, the rotor disk and the rotating shaft are of an integrated structure formed by welding. Alternatively, the rotor disk is threadably connected with the rotating shaft. Alternatively, the rotor disk is in interference fit with the rotating shaft. The rotating shaft assembly comprises a rotating shaft, the rotor disk and the rotating shaft are coaxially connected and fixed together by injection molding or welding fabrication to form an integrated structure, or achieve a fixed connection by threaded connection, interference assembly and the like, so that the connection reliability of the rotating shaft and the rotor disk is effectively guaranteed, and the reliability of synchronous rotation of the rotating shaft and the rotor assembly is guaranteed. Of course, the rotating shaft may be fixedly connected with the rotor disk in other ways, such as by fasteners, etc. For example, the permanent magnet is of a circular or fan-shaped pie structure, the number of the permanent magnets is plural, and the plurality of permanent magnets are uniformly distributed on the axial surface of the rotor disk facing the stator yoke portion111′ circumferentially to form axial magnetic flux; and N poles and S poles of two adjacent permanent magnets are alternately arranged or are arranged in a Halbach array. The permanent magnets have a circular or fan-shaped pie structure, are arranged conveniently, reduce the axial size of the motor100′, and are uniformly distributed on a surface, facing the stator yoke portion111′, of the rotor disk along the circumferential direction of the rotor disk, so that axial magnetic flux is formed between the rotor assembly and the stator assembly1′. N poles and S poles of the two adjacent permanent magnets can be alternately arranged or can be arranged in a Halbach array, and the N poles and the S poles of the two adjacent permanent magnets can be adjusted according to product requirements. Embodiment 3 The difference from Embodiment 2 is as follows: on the basis of Embodiment 2, the motor100′ further comprises an insulating frame, a mounting bracket6′ and a plurality of pins7′, as shown inFIGS.8and9. For example, the insulating frame is mounted on the stator teeth; the mounting bracket6′ is fixedly connected to the insulating frame; a plurality of contact pins7′ are inserted to the mounting bracket6′, wherein lead-out wires of the two groups of windings are fixedly connected to the plurality of contact pins7′. The motor100′ further comprises an insulating frame, a mounting bracket6′ and a plurality of contact pins7′, and the insulating frame is mounted on the stator teeth, which guarantees the safety and reliability of the windings mounted on the stator teeth; the mounting bracket6′ is fixedly connected with the insulating frame, a plurality of contact pins7′ are inserted into the mounting bracket, lead-out wires of the two groups of windings are fixedly connected to the plurality of contact pins7′, and accordingly the lead-out wire heads of the two groups of windings are led to a fixed and stable conductive carrier. The number of the insulating frames is two or two groups, the two or two groups of the insulating frames are respectively mounted on two groups of stator teeth and are respectively referred to as a first insulating frame51′ and a second insulating frame52′, and the mounting bracket6′ is fixedly connected with one of the insulating frames. For example, the mounting bracket6′ is of an arc-shaped strip structure coaxial with the stator assembly1′, and the mounting bracket6′ and the plurality of contact pins7′ are located on the radial outer side of the rotor assembly, as shown inFIG.13. The mounting bracket6′ is of an arc-shaped strip structure coaxial with the stator assembly1′, and the mounting bracket6′ and the plurality of contact pins7′ are located on the radial outer side of the rotor assembly, so that the structure of the motor100′ is relatively regular, the internal magnetic field of the motor100′ is not easily interfered, and meanwhile the motor is convenient to be connected with an external circuit. Further, the motor100′ further comprises a casing8′, as shown inFIG.9, which is an injection molded body and fixedly connects the insulating frame, the mounting bracket6′, the plurality of contact pins7′ and the two bearing covers of the motor100′ to one another to provide an integrated structure, as shown inFIG.13, wherein, an outer diameter of the casing8′ is greater than the maximum radial outer contour surface formed by the stator assembly1′, the insulating frame, the mounting bracket6′, the plurality of contact pins7′; and the two axial end faces of the casing8′ both comprise an inner end face and an outer end face connected with the outer edge of the inner end face, and the outer end face is located on the radial outer side of the inner end face and at least partially protrudes out of the inner end face, so that the two axial end faces of the casing8′ form a stepped structure with high outer height and low inner height, wherein the two inner end faces are flush with the axial end faces of the stator core11′ or do not exceed the axial end faces of the stator core11′. The motor100′ further comprises a casing8′, wherein the casing is an injection molded body for coating the insulating frame, the mounting bracket6′ and other structures, so that the insulating frame, the mounting bracket6′, the plurality of contact pins7′ and two bearing covers can be fixedly connected to form a whole, and the stability of the motor100′ is guaranteed; and the outer diameter of the casing8′ is greater than the maximum radial outer contour surface formed by the stator assembly1′, the insulating frame, the mounting bracket6′ and the plurality of contact pins7′, so that the components are coated in the radial outer surface of the casing8′, and it guarantees the integrity and the regularity of the appearance of the motor100′ and the insulation between the motor and the outside. Meanwhile, the two axial end faces (which can also be called tooth wrapping surfaces81′) of the casing8′ are not regular planes, but are stepped structures with high outer height and low inner height and low outside, as shown inFIGS.9and12, and a portion which is located radially outside and protrudes is referred to as an outer end face which is relatively small in size; and a portion recessed on the inside is referred to as an inner end face which is relatively large in size, as shown inFIGS.9and12. The two inner end faces (i.e., the two axial end faces on the radial inner side of the casing8′) are flush with the two axial end faces of the stator core11′ or do not exceed the two axial end faces of the stator core11′ (i.e., the two groups of tooth surfaces1121′ of the stator core11′), so that the axial air gap between the tooth surfaces and the permanent magnet can be controlled more accurately and effectively. Further, a step surface84′ is provided at a position, close to an axial end of the plurality of contact pins7′, of the casing8′, and the plurality of contact pins7′ pass through the step surface84′ and protrude out of the step surface84′ along the axial direction of the stator assembly1′, as shown inFIG.13. A step surface84′ is arranged at a position, close to an axial end of the plurality of contact pins7′, of the casing8′, so that the plurality of contact pins7′ pass through the step surface84′ and protrude out of the step surface84′ along the axial direction of the stator assembly1′, which can provide an advantageous space for connection or installation of the contact pins and other conductive parts. Further, as shown inFIGS.8and9, the motor100′ further comprises two end packaging covers which are coaxially and fixedly arranged at the two axial ends of the casing8′ respectively for packaging the motor100′ and are provided with shaft holes for extending out the corresponding rotating shafts. The end packaging covers are arranged at the two axial ends of the casing8′, so that the integrity of the motor is100′ guaranteed, and the internal structure of the motor100′ is effectively protected; and the end packaging cover is provided with a shaft hole for allowing the corresponding rotating shaft to extend out, so that the power of the motor100′ can be output. A step is formed between the outer wall surface of the circular boss and the outer wall surface of the casing8′, and the end packaging cover can be provided with a cover edge which is just matched with the step, so that the outer contour of the motor100′ is regular. Among them, an end packaging cover located on one side of the first rotor assembly21′ is referred to as a first end packaging cover101′, and an end packaging cover located on one side of the second rotor assembly22′ is referred to as a second end packaging cover102′. Further, the end packaging cover is provided with a bearing chamber1021′ for receiving the corresponding bearings which are axially outward of the rotating shaft assembly, as shown inFIG.12. The bearing chambers1021′ are arranged on the two end packaging covers to support the bearings (i.e., the bearings relatively close to the outside of the motor100′) axially outward of the two rotating shaft assemblies, so that the two rotational supports can be further supported and limited, and the reliability of the two rotating shaft assemblies is further improved. In addition, the bearing chamber1021′ is integrated on the end packaging cover, so that the end packaging cover also plays a role of the bearing cover. Compared with the solution of setting additional bearing cover and then fixing it on the end packaging cover, the number of components is reduced, the assembly process is simplified, and the production cost is reduced. For example, as shown inFIG.12, the middle part of the end packaging cover is firstly recessed to form a counter sink, the bottom wall of the counter sink is partially reversely protruded to form a boss, and the space defined by the boss is a bearing chamber1021′. Further, the disc body interior of the rotor disk corresponding to the end packaging cover is constructed in a conical slope structure, as shown inFIG.14, to fit the end packaging cover. Therefore, the inner space of the hollow channel can be reasonably utilized, and the axial size of the motor100′ can be further reduced. Further, two outer end faces of the casing8′ are respectively provided with a circular boss coaxial with the stator assembly, as shown inFIG.13, an annular groove1022′ is provided at an edge position of the end packaging cover, and the circular boss is embedded into the corresponding annular groove, as shown inFIG.8. When two circular bosses are arranged on the two outer end faces of the casing8′ (i.e., the two axial end faces on the radial outer side of the casing8′), the two circular bosses are coaxially connected with the stator assembly, and an annular groove1022′ provided in an edge position of the end packaging cover, the circular bosses are embedded in the annular groove1022′ to realize the sealing fit, and the end packaging cover can be assembled in place. The structure is simple, and the assembly is convenient. Here, a circular boss located on one side of the first rotor assembly21′ is referred to as a first circular boss82′, and a circular boss located on one side of the second rotor assembly22′ is referred to as a second circular boss83′. Further, the step surface84′ can be arranged on the inner side wall of one of the circular bosses, as shown inFIG.13, so that the structure of the casing8′ is further simplified. Further, as shown inFIGS.8and9, the motor100′ further comprises an electric control plate9′ internally arranged between the rotor assembly on any side of the motor100′ and the end packaging cover. Due to the arrangement of the electric control plate9′, automatic control of the motor100′ is facilitated; and the electric control plate9′ is arranged on any side of the motor100′ and positioned between the rotor assembly on the side and the end packaging cover, so that the stability of the electric control plate9′ is guaranteed, and the circuit output of the electric control plate9′ is facilitated. As shown inFIG.15, an embodiment of the second aspect of the present disclosure provides a fan, comprising: at least one motor100′ according to any one of the embodiments of the first aspect; and two fans fixedly connected with the two rotating shaft assemblies of the motor100′ respectively, wherein the two fans rotate coaxially and independently. Due to the fact that the fan provided by the embodiment of the second aspect of the present disclosure comprises the motor100′ in any one of the embodiments of the first aspect, the fan has the remarkable advantages of compact structure, strong practical functionality, convenient installation, small axial size, low manufacturing cost and the like. Here, a fan connected with the first rotating shaft assembly31′ is referred to as a first fan100′, and a fan connected with the second rotating shaft assembly32′ is referred to as a second fan300′. In this description, the extension direction of the central axis inFIG.8is simply referred to as “axial direction”, the direction around the central axis is simply referred to as “circumferential direction”, and the direction perpendicular to the central axis is simply referred to as “radial direction”. The motor100′ and the fan provided by the present disclosure are described below in connection with a specific example. As shown inFIGS.8to15, a motor100′ includes a stator assembly1, two rotor assemblies (i.e., a first rotor assembly21′ and a second rotor assembly22′), and two shaft assemblies (i.e., a first rotating shaft assembly31′ and a second rotating shaft assembly32′). In particular, the stator assembly1′ comprises a stator core11′ and two groups of windings (i.e., a first winding121′ and a second winding122′). The stator core11′ is formed by connecting a stator yoke portion111′ and a plurality of removable stator teeth112′ into an integrated structure that is radially hollow and has axially extending teeth, and the stator radial hollow provides an advantageous axial mounting space for the bearings of the motor100′. The first winding121′ and the second winding122′ are respectively wound on the stator tooth bodies1123′ on the two axial sides of the stator, and the first winding121′ and the second winding122′ can act independently of each other on the motor100′. A plurality of rabbets (i.e., clamping slots1111′) are formed on the radial outer side of the stator yoke portion111′ and used for matching and installation of the stator tooth portion112′; and a circular hole groove (i.e., a through hole1112′) is formed on the radial inner side of the stator yoke portion111′ for partially or completely receiving the first rotational support312′ of the first rotating shaft assembly31′ and the second rotational support322′ of the second rotating shaft assembly32′. The single stator tooth portion112′ is provided with at least one tooth body1123′ and at least one tooth surface1121′. After the plurality of stator tooth portions112′ are matched and installed with the stator yoke portion111′, two groups of tooth bodies1123′ and two groups of tooth surfaces1121′ are arranged on the two axial sides of the stator yoke portion111′, and one group of tooth surfaces1121′ which act with the same rotor assembly are in one plane and perpendicular to the axis; and a limit step1122′ is provided on a surface on which the stator tooth portion112′ is matched and installed with the stator yoke portion111′ for abutting against an axial end face of the stator yoke portion111′ to define an axial relative position of the stator tooth portion112′ and the stator yoke portion111′. The first rotor assembly21′ and the second rotor assembly22′ are oppositely and coaxially disposed axially outsides two axial sides of the stator assembly1′ to form an axial air gap with the stator assembly1′. The first rotor assembly21′ comprises a first rotor disk211′ and a first permanent magnet212′, the second rotor assembly22′ comprises a second rotor disk221′ and a second permanent magnet222′, and the first rotor assembly21′ and the second rotor assembly22′ can rotate independently of each other. The first rotor disk211′ and the second rotor disk221′ are generally identical in structure, and one of the rotor disks is illustrated as an example. The radial outer side of the rotor disk is of a disc-shaped structure, and the radial inner side of the rotor disk is of a disc-shaped plane or conical inclined plane structure, providing a favorable space for installation of other parts. The radial outer side of the rotor disk is of a disc-shaped structure, and is fixedly connected with a corresponding rotating shaft in a threaded connection mode. The first permanent magnet212′ and the second permanent magnet222′ are of a circular or fan-shaped pie structure and are uniformly distributed on the axial surface of the rotor disk disc-shaped structure in the circumferential direction to form axial magnetic flux; and N and S poles of two adjacent permanent magnets are alternately arranged or arranged in a Halbach array. The first rotating shaft assembly31′ and the second rotating shaft assembly32′ are coaxially and fixedly connected with the first rotor assembly21′ and the second rotor assembly22′, respectively, and output coaxially from the same axial side of the motor100′, and the first rotating shaft assembly31′ and the second rotating shaft assembly32′ can rotate independently of each other. The first rotating shaft assembly31′ comprises a solid shaft and two bearings, wherein the two bearings are coaxially arranged on the radial outer side of the solid shaft and are respectively disposed on the two axial sides of the solid shaft which is fixedly connected with the first rotor assembly31to form a first rotational support312′; and the second rotating shaft assembly32′ comprises a hollow shaft and two bearings coaxially disposed at the radial outer side of the hollow shaft and respectively disposed on the two axial sides of the hollow shaft which is fixedly connected to the second rotor assembly32to form a second rotational support322′. The first rotational support312′ of the first rotating shaft assembly31′ and the second rotational support322′ of the second rotating shaft assembly32′ are disposed at the two axial sides of the motor100′, and are partially or completely received in the radial hollow of the stator assembly1′. The motor100′ further comprises two bearing covers (i.e., a first bearing cover41′ and a second bearing cover42′), the first bearing cover41′ and the second bearing cover42′ are coaxially and fixedly connected with the stator assembly1′ and are oppositely provided, with outward openings, in a circular hole groove of the stator yoke portion111′ for supporting the bearings of the first rotating shaft assembly31′ and the second rotating shaft assembly32′ close to the inside of the motor100′. The first bearing cover41′ and the second bearing cover42′ are thin-walled cylindrical structures, and the first bearing cover41′ is taken as an example to specifically illustrate that an outer wall411′ of the first bearing cover41′ is matched with a radially inner circular groove hole of the stator yoke portion111′, and an inner wall412′ of the first bearing cover41′ is matched with a bearing of the first rotating shaft assembly31′; and a small flanging413′ is provided radially outside the first bearing cover41′, and a plurality of small notches414′ are uniformly distributed radially on the flanging413′ for rotation stopping and connection. The motor100′ further comprises a first insulating frame51′ and a second insulating frame52′ mounted on the tooth body1123′ of the stator tooth, a mounting bracket6′ fixedly connected to the first insulating frame51′ or the second insulating frame52′, and a plurality of contact pins7′ inserted on the mounting bracket6′. Lead-out wires of the first winding121′ and the second winding122′ are each fixedly connected to the plurality of contact pins7, so that the lead-out wires of the first winding121′ and the second winding122′ are led out to a fixed and stable conductive carrier. The mounting bracket6′ is of an arc-shaped strip structure coaxial with the stator, and the mounting bracket6′ and the plurality of contact pins7′ are located on the radial outer sides of the first rotor assembly21′ and the second rotor assembly22′. The motor100′ further comprises a plastic casing8′ fixedly connecting the stator assembly1′, the first insulating frame51′ and the second insulating frame52′, the mounting bracket6′, the plurality of contact pins7′, the first bearing cover41′ and the second bearing cover42′ to one another to provide an integrated structure. The outer diameter of the plastic casing8′ is greater than the maximum radial outer contour surface formed by the stator assembly1′, the first insulating frame51′, the second insulating frame52′, the mounting bracket6′ and the plurality of contact pins7′; the wrapping surfaces (i.e., the two axial end faces of the casing8′) of the stator tooth portions112′ on the two axial sides are flush or do not exceed the two groups of tooth surfaces1121′ of the stator assembly1′; two cylindrical bosses (i.e., circular bosses) coaxial with the stator assembly1′ are provided on the outer sides of the two axial ends of the plastic casing8′; and the plastic casing8′ is provided with a step surface84′ on the side where the contact pin7′ is located, and the contact pin7′ is exposed out of the step surface84′ by a certain distance, so that a space is provided for connecting or installing the contact pin7′ with other conductive parts. The motor100′ further comprises a first end packaging cover101′ and a second end packaging cover102′, wherein the first end packaging cover101′ and the second end packaging cover102′ respectively pass through a first rotating shaft311′ and a second rotating shaft321′; the first end packaging cover101′ and the second end packaging cover102′ are coaxially and fixedly mounted at the two axial ends of the plastic casing8′ for supporting the bearings of the first rotating shaft assembly31′ and the second rotating shaft assembly32′ close to the outer side of the motor100′ and packaging the motor. Taking the second end packaging cover102′ as an example, the outer side of the second end packaging cover102′ is provided with a spigot (i.e., an annular groove1022′) matched with the cylindrical surface boss (i.e., a second circular boss83′) of the plastic casing, and the radial inner side of the second end packaging cover102′ is provided with a bearing chamber1021′ sinking towards the inner side of the body, thereby submerging the bearing into the inner side of the second end packaging cover102′ to reduce the overall axial size of the motor100′. The motor100′ may further comprise an electric control plate9′ interposed between the first rotor assembly21′ and the first end packaging cover101′ or between the second rotor assembly22′ and the second end packaging cover102′ on either side of the motor100′. The motor100′ may further comprise a support bearing110′ coaxially provided between the output end of the hollow shaft and the solid shaft for increasing the support stiffness of the first rotating shaft assembly31′ and the second rotating shaft assembly32′. A fan comprises a motor100′, a first fan200′, and a second fan300′, wherein the first fan200′ and the second fan300′ are coaxially and fixedly connected with the first rotating shaft assembly31′ and the second rotating shaft assembly32′ respectively output on the two sides of the motor100, and the first fan200′ and the second fan300′ rotate coaxially and independently. Therefore, the motor and the fan have the remarkable advantages of compact structure, strong practical functionality, convenient installation, small axial size, low manufacturing cost and the like. Although the present disclosure has the claims that follow, it is also defined by the following clauses. 1. A motor, comprising:a stator assembly including a stator core and two groups of mutually independent windings, wherein a hollow channel is arranged in a radial middle part of the stator core, two axial end portions of the stator core are provided with stator teeth protruding towards two axial sides of the stator core, and the two groups of windings are wound on two groups of stator teeth respectively;two mutually independent rotor assemblies which are oppositely and coaxially arranged on two axial sides of the stator assembly and form an axial air gap with the stator assembly, wherein the two rotor assemblies are configured to rotate independently; andtwo mutually independent rotating shaft assemblies which are coaxially connected with the two rotor assemblies respectively and protrude in a direction of the same side away from the stator core along the axial direction of the motor, wherein parts of the two rotating shaft assemblies are arranged in the hollow channel. 2. The motor according to clause 1, whereinthe rotating shaft assembly comprises a rotating shaft, wherein the rotating shaft of one of the rotating shaft assemblies is a hollow shaft, and the rotating shaft of another one of the rotating shaft assemblies extends out through the hollow shaft and is suitable for rotating relative to the hollow shaft. 3. The motor according to clause 2, whereinthe rotating shaft of another one of the rotating shaft assemblies comprises a connecting section and an extending section connected with the connecting section, the outer diameter of the connecting section is equal to the outer diameter of the hollow shaft, the connecting section and the hollow shaft are arranged along the axial direction of the hollow channel, and the extending section extends through the hollow shaft. 4. The motor according to clause 2, further comprising:a shaft sleeve provided in the hollow channel, and parts of the two rotating shafts are inserted into the shaft sleeve. 5. The motor according to clause 2, further comprising:a support bearing coaxially provided between an output end portion of the hollow shaft and another one of the rotating shafts. 6. The motor according to any one of clauses 1-5, whereinthe stator core comprises a stator yoke portion and a plurality of stator tooth portions arranged along the circumferential direction of the stator yoke portion, the stator core is formed by assembling the stator tooth portions and the stator yoke portion, the stator tooth portions protrude to two axial sides of the stator yoke portion to form two groups of stator teeth, and the two groups of windings are wound on the stator teeth on the two axial sides of the stator yoke portion respectively. 7. The motor according to clause 6, whereinthe radial middle part of the stator yoke portion is provided with a through hole adapted to the shaft sleeve of the motor, and the through hole forms a part of the hollow channel of the stator core; and/ora radial outer side wall of the stator yoke portion is provided with a clamping slot, and a part of the stator tooth portion is embedded in the clamping slot, so that the stator tooth portion is in clamping fit with the stator yoke portion. 8. The motor according to clause 7, whereinany one of the stator tooth portions comprises at least one stator tooth, the stator tooth comprises a tooth body and a tooth surface connected with one axial end of the tooth body and located on one axial side of the stator yoke portion, and all tooth surfaces of any one of the groups of the stator teeth are located in a same plane and are perpendicular to the axis of the stator yoke portion. 9. The motor according to clause 8, whereinthe stator tooth portion comprises two stator teeth, a limit step is arranged on the tooth body of the stator tooth portion and abuts against the stator yoke portion for limiting axial movement of the stator tooth portion with respect to the stator yoke portion 10. The motor according to any one of clauses 1-5, whereinthe rotor assembly comprises a rotor disk coaxially connected with the rotating shaft assembly and a permanent magnet mounted on the rotor disk, and the rotor disk comprises a disc body exterior and a disc body interior connected with the disc body exterior from outside to inside along the radial direction of the rotor disk, wherein the disc body exterior is of a disc-shaped structure, and the disc body interior is of a disc-shaped structure or a cone-shaped structure. 11. The motor according to clause 10, whereinthe rotating shaft assembly comprises a rotating shaft, and the rotor disk is coaxially connected with the rotating shaft; andthe rotor disk and the rotating shaft are of an integrated structure formed by injection molding or welding, or the rotor disk is in threaded connection or interference fit with the rotating shaft. 12. The motor according to clause 10, whereinthe permanent magnet is of a circular or fan-shaped pie structure, the number of the permanent magnets is plural, and the plurality of permanent magnets are uniformly distributed on the axial surface of the rotor disk facing the stator yoke portion circumferentially to form axial magnetic flux; and N poles and S poles of two adjacent permanent magnets are alternately arranged or are arranged in a Halbach array. 13. The motor according to clause 4, whereinthe rotating shaft assembly comprises a rotating shaft and a rotational support, wherein the rotational support is received in the shaft sleeve and is positioned between the shaft sleeve and the rotating shaft for supporting the rotating shaft and enabling the rotating shaft to be suitable for rotating relative to the shaft sleeve, and the rotating shaft is coaxially connected with the rotor assembly. 14. The motor according to clause 13, whereinthe rotational support comprises at least one bearing. 15. The motor according to clause 14, whereinthe number of the bearings is plural, and the plurality of bearings are distributed on the same axial side of the rotor assembly at intervals along a length direction of the rotating shaft. 16. The motor according to clause 15, whereinan outer side wall of the shaft sleeve is matched with the hollow channel, an inner side wall of the shaft sleeve is matched with the bearing, and the shaft sleeve is matched with the hollow channel by a concave-convex structure to limit the axial movement of the shaft sleeve relative to the stator assembly. 17. The motor according to clause 16, whereinthe concave-convex structure comprises a flange arranged on the outer side wall of the shaft sleeve and a groove arranged on the wall surface of the hollow channel; andthe flange is further provided with at least one notch. 18. The motor according to clause 14, whereina separation portion is provided on the inner side wall of the shaft sleeve for separating the two rotational supports at intervals. 19. The motor according to any one of clauses 1-5, further comprising:an insulating frame mounted on the stator teeth;a mounting bracket fixedly connected to the insulating frame; anda plurality of contact pins inserted to the mounting bracket, wherein lead-out wires of the two groups of windings are fixedly connected to the plurality of contact pins. 20. The motor according to clause 19, whereinthe mounting bracket is of an arc-shaped strip structure coaxial with the stator assembly, and the mounting bracket and the plurality of contact pins are located on the radial outer side of the rotor assembly. 21. The motor according to clause 19, further comprising:a casing which is an injection molded body and fixedly connects the insulating frame, the mounting bracket, the plurality of contact pins and the shaft sleeve of the motor to one another to provide an integrated structure, wherein, an outer diameter of the casing is greater than the maximum radial outer contour surface formed by the stator assembly, the insulating frame, the mounting bracket, the plurality of contact pins; and two axial end faces of the casing comprises an inner end face and an outer end face connected with an outer edge of the inner end face, and the outer end face is located on the radial outer side of the inner end face and at least partially protrudes out of the inner end face, so that the two axial end faces of the casing form a stepped structure with high outer height and low inner height, wherein the two inner end faces are flush with the two axial end faces of the stator core or do not exceed the two axial end faces of the stator core. 22. The motor according to clause 21, whereintwo outer end faces of the casing are respectively provided with a circular boss coaxial with the stator assembly. 23. The motor according to clause 21, whereina step surface is provided at a position, close to an axial end of the plurality of contact pins, of the casing, and the plurality of contact pins pass through the step surface and protrude out of the step surface along the axial direction of the stator assembly. 24. The motor according to clause 21, further comprising:two end packaging covers which are coaxially and fixedly mounted at the two axial ends of the casing respectively for packaging the motor and are provided with shaft holes for extending out the rotating shaft assembly. 25. The motor according to clause 24, further comprising:an electric control plate internally arranged between the rotor assembly on any side of the motor and the end packaging cover. 26. The motor according to clause 4, further comprising:two shaft sleeve packaging covers which are fixedly connected at axial ports of the shaft sleeves for limiting the axial movement of the rotating shaft assemblies. 27. A fan, comprising:at least one motor according to any one of clauses 1 to 26;two fans fixedly connected with the two rotating shaft assemblies of the motor respectively, wherein the two fans rotate coaxially and independently. 28. A motor, comprising:a stator assembly including a stator core and two groups of mutually independent windings, wherein a hollow channel is arranged in a radial middle part of the stator core, two axial end portions of the stator core are provided with stator teeth protruding towards two axial sides of the stator core, and the two groups of windings are wound on two groups of stator teeth respectively;two mutually independent rotor assemblies which are oppositely and coaxially arranged on two axial sides of the stator assembly and form an axial air gap with the stator assembly, wherein the two rotor assemblies are configured to rotate independently; andtwo mutually independent rotating shaft assemblies including a rotating shaft and a rotational support, wherein the rotational support is at least partially received in the hollow channel and sleeved on the rotating shaft for supporting the rotating shaft and enabling the rotating shaft to be suitable for rotating relative to the stator core, and the two rotating shafts are coaxially connected with the two rotor assemblies respectively and protrude in a direction of the same side away from the stator core along the axial direction of the motor. 29. The motor according to clause 28, whereinthe rotational support comprises at least one bearing. 30. The motor according to clause 29, whereinthe number of the bearings is plural, and the plurality of bearings are distributed on the two axial sides of the corresponding rotor assembly at intervals along the length direction of the rotating shaft. 31. The motor according to clause 30, further comprising:two bearing covers sleeved in the hollow channel and fixedly connected with the stator core, wherein the two bearing covers are arranged opposite to each other for respectively supporting the bearings axially inwards of the corresponding rotating shaft assemblies. 32. The motor according to clause 31, whereinthe bearing cover is adapted to the shape of the bearing, and the bearing is received in the bearing cover and supported by the bearing cover. 33. The motor according to clause 32, whereinan open end of the bearing cover is provided with a flanging extending radially outwards. 34. The motor according to clause 33, whereinthe flanging is provided with at least one notch. 35. The motor according to clauses 28-34, whereinthe rotating shaft of one of the rotating shaft assemblies is a hollow shaft, and the rotating shaft of another one of the rotating shaft assemblies extends out through the hollow shaft and is suitable for rotating relative to the hollow shaft. 36. The motor according to clause 35, whereinthe rotating shaft of another one of the rotating shaft assemblies comprises a connecting section and an extending section connected with the connecting section, the outer diameter of the connecting section is equal to the outer diameter of the hollow shaft, the connecting section and the hollow shaft are arranged along the axial direction of the hollow channel, and the extending section extends through the hollow shaft. 37. The motor according to clause 35, further comprising:a support bearing coaxially provided between an output end portion of the hollow shaft and another one of the rotating shafts. 38. The motor according to clauses 28-34, whereinthe stator core comprises a stator yoke portion and a plurality of stator tooth portions arranged along the circumferential direction of the stator yoke portion, the stator core is formed by assembling the stator tooth portions and the stator yoke portion, the stator tooth portions protrude to two axial sides of the stator yoke portion to form two groups of stator teeth, and the two groups of windings are wound on the stator teeth on the two axial sides of the stator yoke portion respectively. 39. The motor according to clause 38, whereinthe radial middle part of the stator yoke portion is provided with a through hole adapted to the bearing cover of the motor, and the through hole forms a part of the hollow channel of the stator core; and/ora radial outer side wall of the stator yoke portion is provided with a clamping slot, and a part of the stator tooth portion is embedded in the clamping slot, so that the stator tooth portion is in clamping fit with the stator yoke portion. 40. The motor according to clause 39, whereinany one of the stator tooth portions comprises at least one stator tooth, the stator tooth comprises a tooth body and a tooth surface connected with one axial end of the tooth body and located on one axial side of the stator yoke portion, and all tooth surfaces of any one of the groups of the stator teeth are located in a same plane and are perpendicular to the axis of the stator yoke portion. 41. The motor according to clause 40, whereinthe stator tooth portion comprises two stator teeth, a limit step is arranged on the tooth body of the stator tooth portion and abuts against the stator yoke portion for limiting axial movement of the stator tooth portion with respect to the stator yoke portion. 42. The motor according to clauses 28-34, whereinthe rotor assembly comprises a rotor disk coaxially connected with the corresponding rotating shaft and a permanent magnet mounted on the rotor disk, and the rotor disk comprises a disc body exterior and a disc body interior connected with the disc body exterior from outside to inside along the radial direction of the rotor disk, wherein the disc body exterior is of a disc-shaped structure, and the disc body interior is of a disc-shaped structure or a cone-shaped structure. 43. The motor according to clause 42, whereinthe rotor disk and the corresponding rotating shaft are of an integrated structure formed by injection molding or welding; orthe rotor disk is in threaded connection or interference fit with the rotating shaft. 44. The motor according to clause 42, whereinthe permanent magnet is of a circular or fan-shaped pie structure, the number of the permanent magnets is plural, and the plurality of permanent magnets are uniformly distributed on the axial surface of the rotor disk facing the stator yoke portion circumferentially to form axial magnetic flux; and N poles and S poles of two adjacent permanent magnets are alternately arranged or are arranged in a Halbach array. 45. The motor according to any one of clauses 28-34, further comprising:an insulating frame mounted on the stator teeth;a mounting bracket fixedly connected to the insulating frame; anda plurality of contact pins inserted to the mounting bracket, wherein lead-out wires of the two groups of windings are fixedly connected to the plurality of contact pins. 46. The motor according to clause 45, whereinthe mounting bracket is of an arc-shaped strip structure coaxial with the stator assembly, and the mounting bracket and the plurality of contact pins are located on the radial outer side of the rotor assembly. 47. The motor according to clause 45, further comprising:a casing which is an injection molded body and fixedly connects the insulating frame, the mounting bracket, the plurality of contact pins and the two bearing covers of the motor to one another provide an integrated structure, wherein, an outer diameter of the casing is greater than the maximum radial outer contour surface formed by the stator assembly, the insulating frame, the mounting bracket, the plurality of contact pins; and two axial end faces of the casing comprises an inner end face and an outer end face connected with an outer edge of the inner end face, and the outer end face is located on the radial outer side of the inner end face and at least partially protrudes out of the inner end face, so that the two axial end faces of the casing form a stepped structure with high outer height and low inner height, wherein the two inner end faces are flush with the two axial end faces of the stator core or do not exceed the two axial end faces of the stator core. 48. The motor according to clause 47, whereina step surface is provided at a position, close to an axial end of the plurality of contact pins, of the casing, and the plurality of contact pins pass through the step surface and protrude out of the step surface along the axial direction of the stator assembly. 49. The motor according to clause 47, further comprising:two end packaging covers which are coaxially and fixedly mounted at the two axial ends of the casing respectively for packaging the motor and are provided with shaft holes for extending out the corresponding rotating shafts. 50. The motor according to clause 49, whereinthe end packaging cover is provided with a bearing chamber for receiving the corresponding bearings which are axially outward of the rotating shaft assembly. 51. The motor according to clause 49, whereintwo outer end faces of the casing are respectively provided with a circular boss coaxial with the stator assembly, an annular groove is provided at an edge position of the end packaging cover, and the circular boss is embedded into the corresponding annular groove. 52. The motor according to clause 49, further comprising:an electric control plate internally arranged between the rotor assembly on any side of the motor and the end packaging cover. 53. A fan, comprising:at least one motor according to any one of clauses 28-52;two fans fixedly connected with the two rotating shaft assemblies of the motor respectively, wherein the two fans rotate coaxially and independently. In summary, according to the motor provided by the present disclosure, dual-power independent output of one motor is realized by matching one stator assembly, two mutually independent rotor assemblies and two mutually independent rotating shaft assemblies, and two fans can be driven to independently rotate at respective rotating speeds and directions without interference. Compared with the solution that the two motors are respectively connected with the two fans in a backward axial extension mode, in the present disclosure, at least one stator assembly is omitted, the axial size of the fan is reduced, and the cost of the fan is reduced. Compared with the solution that a single-shaft motor and a gear mechanism are matched to realize the shaft extension at both ends, in the present disclosure, the two fans rotate at any rotating speed and direction, the practical functionality is strong, the diversification of the fan functionality is remarkably improved, the gear mechanism is omitted, and the manufacturing and installation difficulty of products is reduced. In the present disclosure, the terms “first”, “second”, “third” are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term “plurality” refers to two or more, unless explicitly defined otherwise. The terms “mounted”, “connected”, “connecting”, “fixed”, and the like are to be construed broadly, e.g., “connecting” may be a fixed connection, a removable connection, or an integral connection; “connected” may be directly connected or indirectly connected by an intermediary. The specific meaning of the above terms in the present disclosure will be understood in specific circumstances by those of ordinary skill in the art. In the description of the present disclosure, it should be understood that the directional or positional relationships indicated by the terms “upper”, “lower”, “left”, “right” and the like are based on the directional or positional relationships shown in the drawings. It is merely for the purpose of describing the present disclosure and simplifying the description, and is not intended to indicate or imply that a particular orientation, configuration and operation of the referenced device or unit is required and should not be construed as limiting the present disclosure. In the description of this description, reference to the terms “an embodiment”, “some embodiments”, and “a specific embodiment”, etc., means that specific features, structures, materials, or characteristics described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In the present specification, schematic statement of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The above mentioned are merely preferred embodiments of the present disclosure and not intended to limit the present disclosure. The present disclosure may have various modifications and changes for those skilled in the art. Any modifications, equivalents, improvements, etc. within the spirit and principles of the present disclosure are intended to be included within the scope of the present disclosure. | 116,519 |
11863031 | DESCRIPTION OF EMBODIMENTS The following describes the embodiments with reference to the drawings. Parts of the embodiments functionally or structurally corresponding to each other or associated with each other will be denoted by the same reference numbers or by reference numbers which are different in the hundreds place from each other. The corresponding or associated parts may refer to the explanation in the other embodiments. The rotating electrical machine in each embodiment is configured to be used, for example, as a power source for vehicles. The rotating electrical machine may, however, be used widely for industrial, automotive, domestic, office automation, or game applications. In the following embodiments, the same or equivalent parts will be denoted by the same reference numbers in the drawings, and explanation thereof in detail will be omitted. First Embodiment A rotating electrical machine10in this embodiment is a synchronous polyphase alternating-current motor having an outer rotor structure (i.e., an outer rotating structure). The outline of the rotating electrical machine10is illustrated inFIGS.1to5. FIG.1is a perspective longitudinal sectional view of the rotating electrical machine10.FIG.2is a longitudinal sectional view along the rotating shaft11of the rotating electrical machine10.FIG.3is a traverse sectional view (i.e., sectional view taken along the line III-III inFIG.2) of the rotating electrical machine10perpendicular to the rotating shaft11. FIG.4is a partially enlarged sectional view ofFIG.3.FIG.5is an exploded view of the rotating electrical machine10.FIG.3omits hatching showing a section except the rotating shaft11for the sake of simplicity of the drawings. In the following discussion, a lengthwise direction of the rotating shaft11will also be referred to as an axial direction. A radial direction from the center of the rotating shaft11will be simply referred to as a radial direction. A direction along a circumference of the rotating shaft11about the center thereof will be simply referred to as a circumferential direction. The rotating electrical machine10includes a bearing unit20, a housing30, a rotor40, a stator50, and an inverter unit60. These members are arranged coaxially with each other together with the rotating shaft11and assembled in a given sequence to complete the rotating electrical machine10. The rotating electrical machine10in this embodiment is equipped with the rotor40working as a magnetic field generator or a field system and the stator50working as an armature and engineered as a revolving-field type rotating electrical machine. The bearing unit20includes two bearings21and22arranged away from each other in the axial direction and the retainer23which retains the bearings21and22. The bearings21and22are implemented by, for example, radial ball bearings each of which includes the outer race25, the inner race26, and a plurality of balls27disposed between the outer race25and the inner race26. The retainer23is of a cylindrical shape. The bearings21and22are disposed radially inside the retainer23. The rotating shaft11and the rotor40are retained radially inside the bearings21and22to be rotatable. The bearings21and22are used as a set of bearings to rotatably retain the rotating shaft11. Each of the bearings21and22holds the balls27using a retainer, not shown, to keep a pitch between the balls27constant. Each of the bearings21and22is equipped with seals on axially upper and lower ends of the retainer and also has non-conductive grease (e.g., non-conductive urease grease) installed inside the seals. The position of the inner race26is mechanically secured by a spacer to exert constant inner precompression on the inner race26in the form of a vertical convexity. The housing30includes a cylindrical peripheral wall31. The peripheral wall31has a first end and a second end opposed to each other in an axial direction thereof. The peripheral wall31has an end surface32on the first end and the opening33in the second end. The opening33occupies the entire area of the second end. The end surface32has formed in the center thereof a circular hole34. The bearing unit20is inserted into the hole34and fixed using a fastener, such as a screw or a rivet. The rotor40, which has a hollow cylindrical shape, and the stator50, which has a hollow cylindrical shape, are disposed in an inner space defined by the peripheral wall31and the end surface32within the housing30. In this embodiment, the rotating electrical machine10is of an outer rotor type, so that the stator50is arranged radially inside the cylindrical rotor40within the housing30. The rotor40is retained in a cantilever form by a portion of the rotating shaft11close to the end surface32in the axial direction. The rotor40includes a hollow cylindrical magnetic holder41and an annular magnet unit42disposed radially inside the magnet holder41. The magnet holder41is of substantially a cup-shape and works as a magnet holding member. The magnet holder41includes a cylinder43, an attaching portion44which is of a cylindrical shape and smaller in diameter than the cylinder43, and an intermediate portion45connecting the cylinder43and the attaching portion44together. The cylinder43has the magnet unit42secured to an inner peripheral surface thereof. The magnet holder41is made of cold rolled steel (SPCC), forging steel, or carbon fiber reinforced plastic (CFRP) which have a required degree of mechanical strength. The attaching portion44has a through-hole44a, and the rotating shaft11passes through the through-hole44aof the attaching portion44. The attaching portion44is secured to a portion of the rotating shaft11disposed inside the through-hole44a. In other words, the magnet holder41is secured to the rotating shaft11through the attaching portion44. The attaching portion44may preferably be joined to the rotating shaft11using concavities and convexities, such as a spline joint or a key joint, welding, or crimping, so that the rotor40rotates along with the rotating shaft11. The bearings21and22of the bearing unit20are secured radially outside the attaching portion44. The bearing unit20is, as described above, fixed on the end surface32of the housing30, so that the rotating shaft11and the rotor40are retained by the housing30to be rotatable. The rotor40is, thus, rotatable within the housing30. The rotor40is equipped with the attaching portion44arranged only one of ends thereof opposed to each other in the axial direction of the rotor40. This cantilevers the rotor40on the rotating shaft11. The attaching portion44of the rotor40is rotatably retained at two points of supports using the bearings21and22of the bearing unit20which are located away from each other in the axial direction. In other words, the rotor40is held to be rotatable using the two bearings21and22which are separate at a distance away from each other in the axial direction on one of the axially opposed ends of the magnet holder41. This ensures the stability in rotation of the rotor40even though the rotor40is cantilevered on the rotating shaft11. The rotor40is retained by the bearings21and22at locations which are away from the center intermediate between the axially opposed ends of the rotor40in the axial direction thereof. The bearing22of the bearing unit20, which is located closer to the center of the rotor40(a lower one of the bearings21and22in the drawings), has gaps between each of the outer and inner races25and26and the balls27, and the bearing21of the bearing unit20, which is located farther away from the center of the rotor40(i.e., an upper one of the bearings21and22), has gaps between each of the outer and inner races25and26and the balls27. These gaps of the bearing22are different in dimension from these gaps of the bearing21. For instance, the bearing22closer to the center of the rotor40is greater in the dimension of the gaps from the bearing21. This minimizes adverse effects on the bearing unit20which arise from deflection of the rotor or mechanical vibration of the rotor40due to imbalance resulting from parts tolerance at a location of the bearing unit20close to the center of the rotor40. Specifically, the bearing22closer to the center of the rotor40is engineered to have dimensions of the gaps or plays increased using precompression, thereby absorbing the vibration generating in the cantilever structure. The precompression may be provided by either fixed position preload or constant pressure preload. In the case of the fixed position preload, the outer race25of each of the bearings21and22is joined to the retainer23using press-fitting or welding. The inner race26of each of the bearings21and22is joined to the rotating shaft11by press-fitting or welding. The precompression may be created by placing the outer race25of the bearing21away from the inner race26of the bearing21in the axial direction or alternatively placing the outer race25of the bearing22away from the inner race26of the bearing22in the axial direction. In the case of the constant pressure preload, a preload spring, such as a wave washer24, is arranged between the bearing22and the bearing21to create the preload directed from a region between the bearing22and the bearing21toward the outer race25of the bearing22in the axial direction. In this case, the inner race26of each of the bearing21and the bearing22is joined to the rotating shaft11using press fitting or bonding. The outer race of the bearing21or the bearing22is arranged away from the outer race through a given clearance. This structure exerts pressure, as produced by the preload spring, on the outer race25of the bearing22to urge the outer race25away from the bearing21. The pressure is then transmitted through the rotating shaft11to urge the inner race26of the bearing21toward the bearing22, thereby bringing the outer race25of each of the bearings21and22away from the inner race26thereof in the axial direction to exert the preload on the bearings21and22in the same way as the fixed position preload. The constant pressure preload does not necessarily need to exert the spring pressure, as illustrated inFIG.2, on the outer race25of the bearing22, but may alternatively be created by exerting the spring pressure on the outer race25of the bearing21. The exertion of the preload on the bearings21and22may alternatively be achieved by placing the inner race26of one of the bearings21and22away from the rotating shaft11through a given clearance therebetween and joining the outer race25of each of the bearings21and22to the retainer23using press-fitting or bonding. Further, in the case where the pressure is created to bring the inner race26of the bearing21away from the bearing22, such pressure is preferably additionally exerted on the inner race26of the bearing22away from the bearing21. Conversely, in the case where the pressure is created to bring the inner race26of the bearing21close to the bearing22, such pressure is preferably additionally exerted on the inner race26of the bearing22to bring it close to the bearing21. In a case where the rotating electrical machine10is used as, for example, a power source for a vehicle, there is a possibility that mechanical vibration having a component oriented in a direction in which the preload is created may be exerted on the preload generating structure or that a direction in which the force of gravity acts on an object to which the preload is applied may be changed. In order to alleviate such a problem, the fixed position preload is preferably used in the case where the rotating electrical machine10is mounted in a vehicle. The intermediate portion45includes an annular inner shoulder49aand an annular outer shoulder49b. The outer shoulder49bis arranged outside the inner shoulder49ain the radial direction of the intermediate portion45. The inner shoulder49aand the outer shoulder49bare separate from each other in the axial direction of the intermediate portion45. This layout results in a partial overlap between the cylinder43and the attaching portion44in the radial direction of the intermediate portion45. In other words, the cylinder43protrudes outside a base end portion (i.e., a lower portion, as viewed in the drawing) of the attaching portion44in the axial direction. The structure in this embodiment enables the rotor40to be retained by the rotating shaft11at a location closer to the center of gravity of the rotor40than a case where the intermediate portion45is shaped to be flat without any shoulder, thereby ensuring the stability in operation of the rotor40. In the above structure of the intermediate portion45, the rotor40has an annular bearing housing recess46which is formed in an inner portion of the intermediate portion45and radially surrounds the attaching portion44. The bearing housing recess46has a portion of the bearing unit disposed therein. The rotor40also has a coil housing recess47which is formed in an outer portion of the intermediate portion45and radially surrounds the bearing housing recess46. The coil housing recess47has disposed therein the coil end54of a stator coil, i.e., a stator winding,51of the stator50, which will be described later in detail. The housing recesses46and47are arranged adjacent each other in the axial direction. In other words, a portion of the bearing unit20is laid to overlap the coil end54of the stator coil51in the axial direction. This enables the rotating electrical machine to have a length decreased in the axial direction. The intermediate portion45extends or overhangs outward from the rotating shaft11in the radial direction. The intermediate portion45is equipped with a contact avoider which extends in the axial direction and avoids a physical contact with the coil end54of the stator coil51of the stator50. The intermediate portion45will also be referred to as an overhang. The coil end54may be bent radially inwardly or outwardly to have a decreased axial dimension, thereby enabling the axial length of the stator50to be decreased. A direction in which the coil end54is bent is preferably determined depending upon installation thereof in the rotor40. In the case where the stator50is installed radially inside the rotor40, a portion of the coil end54, which is inserted into the rotor40, is preferably bent radially inwardly. A coil end opposite the coil end54may be bent either inwardly or outwardly, but is preferably bent to an outward side where there is an enough space in terms of the production thereof. The magnet unit42working as a magnetic portion is made up of a plurality of permanent magnets which are disposed radially inside the cylinder43to have different magnetic poles arranged alternately in a circumferential direction thereof. The magnet unit42, thus, has a plurality of magnetic poles arranged in the circumferential direction. The magnet unit42will also be described later in detail. The stator50is arranged radially inside the rotor40. The stator50includes the stator coil51wound in a substantially cylindrical (annular) form and a stator core52used as a base member arranged radially inside the stator coil51. The stator coil51is arranged to face the annular magnet unit42through a given air gap therebetween. The stator coil51includes a plurality of phase windings each of which is made of a plurality of conductors which are arranged at given pitches away from one another in the circumferential direction and joined together. In this embodiment, first and second sets of three-phase windings: The first set includes a U-phase winding, a V-phase winding, and a W-phase winging, and the second set includes an X-phase winding, a Y-phase winding, and a Z-phase winding. The stator coil51uses these first and second sets of three-phase windings so as to serve as a six-phase coil. The stator core52is formed by an annular stack of magnetic steel plates made of soft magnetic material and mounted radially inside the stator coil51. The magnetic steel plates are, for example, silicon nitride steel plates made by adding a small percent (e.g., 3%) of silicon nitride to iron. The stator coil51corresponds to an armature winding. The stator core52corresponds to an armature core. The stator coil51overlaps the stator core52in the radial direction and includes a coil side portion53disposed radially outside the stator core52, and the coil ends54and55overhanging respective ends of the stator core52in the axial direction. The coil side portion53faces the stator core52and the magnet unit42of the rotor40in the radial direction. The stator50is arranged inside the rotor40. The coil end54, which is one (i.e., an upper one, as viewed in the drawings) of the axially opposed coil ends54and55and arranged close to the bearing unit20, is disposed in the coil housing recess47defined by the magnet holder41of the rotor40. The stator50will also be described later in detail. The inverter unit60includes a unit base61secured to the housing using fasteners, such as bolts, and a plurality of electrical components62mounted on the unit base61. The unit base61is made from, for example, carbon fiber reinforced plastic (CFRP). The unit base61includes an end plate63secured to an edge of the opening33of the housing30and a casing64which is formed integrally with the end plate63and extends in the axial direction. The end plate63has a circular opening65formed in the center thereof. The casing64extends upward from a peripheral edge of the opening65. The stator50is arranged on an outer peripheral surface of the casing64. Specifically, an outer diameter of the casing64is selected to be identical with or slightly smaller than an inner diameter of the stator core52. The stator core52is attached to the outer side of the casing64to complete a unit made up of the stator50and the unit base61. The unit base61is secured to the housing30, so that the stator50is unified with the housing50in a condition where the stator core52is installed on the casing64. The stator core52may be bonded, shrink-fit, or press-fit on the unit base61, thereby eliminating positional shift of the stator core52relative to the unit base61both in the circumferential direction and in the axial direction. The casing64has a radially inner storage space in which the electrical components62are disposed. The electrical components62are arranged to surround the rotating shaft11within the storage space. The casing64functions as a storage space forming portion. The electrical components62include semiconductor modules66, a control board67, and a capacitor module68which constitute an inverter circuit. The unit base61serves as a stator holder (i.e., an armature holder) which is arranged radially inside the stator50and retains the stator50. The housing30and the unit base61define a motor housing for the rotating electrical machine10. In the motor housing, the retainer23is secured to a first end of the housing30which is opposed to a second end of the housing through the rotor40in the axial direction. The second end of the housing30and the unit base61are joined together. For instance, in an electric-powered vehicle, such as an electric automobile, the motor housing is attached to a side of the vehicle to install the rotating electrical machine10in the vehicle. The inverter unit60will be also described usingFIG.6that is an exploded view in addition toFIGS.1to5. The casing64of the unit base61includes a cylinder71and an end surface72that is one of ends of the cylinder71which are opposed to each other in the axial direction of the cylinder71(i.e., the end of the casing64closer to the bearing unit20). The end of the cylinder71opposed to the end surface72in the axial direction is shaped to fully open to the opening65of the end plate63. The end surface72has formed in the center thereof a circular hole73through which the rotating shaft11is insertable. The hole73has fitted therein a sealing member171which hermetically seals an air gap between the hole73and the outer periphery of the rotating shaft11. The sealing member171is preferably implemented by, for example, a resinous slidable seal. The cylinder71of the casing64serves as a partition which isolates the rotor40and the stator50arranged radially outside the cylinder71from the electrical components62arranged radially inside the cylinder71. The rotor40, the stator50, and the electrical components62are arranged to be radially aligned from the inside of the cylinder71to the outside thereof. The electrical components62are electrical devices making up the inverter circuit equipped with a motor function and a generator function. The motor function is to deliver electrical current to the phase windings of the stator coil51in a given sequence to turn the rotor40. The generator function is to receive a three-phase ac current flowing through the stator coil51in response to the rotation of the rotating shaft11and generate and output electrical power. The electrical components62may be engineered to perform either one of the motor function and the generator function. In a case where the rotating electrical machine10is used as a power source for a vehicle, the generator function serves as a regenerative function to output a regenerated electrical power. Specifically, the electrical components62, as demonstrated inFIG.4, include the capacitor module68, which has a hollow cylindrical shape, arranged around the rotating shaft11, and the semiconductor modules66mounted on the outer peripheral surface of the capacitor module68. The capacitor module68has a plurality of smoothing capacitors68aconnected in parallel to each other. Specifically, each of the capacitors68ais implemented by a stacked-film capacitor which is made of a plurality of film capacitors stacked in a trapezoidal shape in cross section. In this embodiment, twelve capacitors68aare arranged annularly to constitute the capacitor module68. The capacitors68amay be produced by preparing a long film which has a given width and is made of a stack of films and cutting the long film into isosceles trapezoids each of which has a height identical with the width of the long film and whose short bases and long bases are alternately arranged. Mounting electrodes to the thus produced capacitor devices enables the capacitors68ato be completed. Each semiconductor module66includes, for example, a semiconductor switch, such as a MOSFET or an IGBT and is of substantially a planar shape. In this embodiment, the rotating electrical machine10is, as described above, equipped with the first and second sets of three-phase windings and has the inverter circuits, one for each set of the three-phase windings. The electrical components62, therefore, include a total of twelve semiconductor modules66which are arranged in an annular form to make up a semiconductor module group66A. The semiconductor modules66are interposed between the cylinder71of the casing64and the capacitor module68. The semiconductor module group66A has an outer peripheral surface placed in contact with an inner peripheral surface of the cylinder71. The semiconductor module group66A also has an inner peripheral surface placed in contact with an outer peripheral surface of the capacitor module68. This causes heat, as generated in the semiconductor modules66, to be transferred to the end plate63through the casing64, so that it is dissipated from the end plate63. The semiconductor module group66A preferably has spacers69disposed radially outside the outer peripheral surface thereof, i.e., between the semiconductor modules66and the cylinder71. A combination of the capacitor modules68is so arranged as to have a regular dodecagonal section extending perpendicular to the axial direction thereof, while the inner periphery of the cylinder71has a circular transverse section. The spacers69are, therefore, each shaped to have a flat inner peripheral surface and a curved outer peripheral surface. The spacers69may alternatively be formed integrally with each other in an annular shape and disposed radially outside the semiconductor module group66A. The spacers69are highly thermally conductive and made of, for example, metal, such as aluminum or heat dissipating gel sheet. The inner periphery of the cylinder71may alternatively be shaped to have a dodecagonal transverse section like the capacitor modules68. In this case, the spacers69are each preferably shaped to have a flat inner peripheral surface and a flat outer peripheral surface. In this embodiment, the cylinder71of the casing64has formed therein a coolant path74through which coolant flows. The heat generated in the semiconductor modules66is also released to the coolant flowing in the coolant path74. In other words, the casing64is equipped with a cooling mechanism. The coolant path74is, as clearly illustrated inFIGS.3and4, formed in an annular shape and surrounds the electrical components62(i.e., the semiconductor modules66and the capacitor module68). The semiconductor modules66are arranged along the inner peripheral surface of the cylinder71. The coolant path74is laid to overlap the semiconductor modules66in the radial direction. The stator50is arranged outside the cylinder71. The electrical components62are arranged inside the cylinder71. This layout causes the heat to be transferred from the stator50to the outer side of the cylinder71and also transferred from the electrical components62(e.g., the semiconductor modules66) to the inner side of the cylinder71. It is possible to simultaneously cool the stator50and the semiconductor modules66, thereby facilitating dissipation of thermal energy generated by heat-generating members of the rotating electrical machine10. Further, at least one of the semiconductor modules66, which constitute part or all of the inverter circuits serving to energize the stator coil51to drive the rotating electrical machine, is arranged in a region surrounded by the stator core52disposed radially outside the cylinder71of the casing64. Preferably, one of the semiconductor modules66may be arranged fully inside the region surrounded by the stator core52. More preferably, all the semiconductor modules66may be arranged fully in the region surrounded by the stator core52. At least a portion of the semiconductor modules66is arranged in a region surrounded by the coolant path74. Preferably, all the semiconductor modules66may be arranged in a region surrounded by the yoke141. The electrical components62include an insulating sheet75disposed on one of axially opposed end surfaces of the capacitor module68, and a wiring module76disposed on the other end surface of the capacitor module68. The capacitor module68has two axially-opposed end surfaces: a first end surface and a second end surface. The first end surface of the capacitor module68closer to the bearing unit20faces the end surface72of the casing64and is laid on the end surface72through the insulating sheet75. The second end surface of the capacitor module68closer to the opening65has the wiring module76mounted thereon. The wiring module76includes a resin-made circular plate-shaped body76aand a plurality of bus bars76band76cembedded in the body76a. The bus bars76band76celectrically connect the semiconductor modules66and the capacitor module68together. Specifically, the semiconductor modules66are equipped with connecting pins66aextending from axial ends thereof. The connecting pins66aconnect with the bus bars76bradially outside the body76a. The bus bars76cextend away from the capacitor module68radially outside the body76aand have top ends connecting with the wiring members79(seeFIG.2). The capacitor module68, as described above, has the insulating sheet75mounted on the first end surface thereof. The capacitor module68also has the wiring module76mounted on the second end surface thereof. The capacitor module68, therefore, has first and second heat dissipating paths which respectively extend from the first and second end surfaces of the capacitor module68to the end surface72and the cylinder71. Specifically, the first heat dissipating path is defined which extends from the first end surface to the end surface72. The second heat dissipating path is defined which extends from the second end surface to the cylinder71. This enables the heat to be released from the end surfaces of the capacitor module68other than the outer peripheral surface on which the semiconductor modules66are arranged. In other words, it is possible to dissipate the heat not only in the radial direction, but also in the axial direction. The capacitor module68is of a hollow cylindrical shape, and the rotating shaft11is arranged within the capacitor module68at a given interval away from the inner periphery of the capacitor module68, so that heat generated by the capacitor module68will be dissipated from the hollow cylindrical space. The rotation of the rotating shaft11usually produces a flow of air, thereby enhancing cooling effects. The control board67, which has a discotic shape, is mounted to the wiring module76. The control board67includes a printed circuit board (PCB) on which given wiring patterns are formed and also has ICs and the control device77mounted thereon. The control device77serves as a controller and is comprised of a microcomputer. The control board67is secured to the wiring module76using fasteners, such as screws. The control board67has formed in the center thereof a hole67athrough which the rotating shaft11passes. The wiring module76has a first surface and a second surface opposed to each other in the axial direction, that is, a thickness-wise direction of the wiring module76. The first surface faces the capacitor module68. The wiring module76has the control board67mounted on the second surface thereof. The bus bars76cof the wiring module76extend from one of surfaces of the control board67to the other. The control board67may have cut-outs for avoiding physical interference with the bus bars76c. For instance, the control board67may have the cut-outs formed in portions of the circular outer edge thereof. The electrical components62are, as described already, arranged inside a space surrounded by the casing64. The housing30, the rotor40, and the stator50are disposed outside the space in the form of layers. This structure serves to shield against electromagnetic noise generated in the inverter circuits. Specifically, each inverter circuit works to control switching operations of the corresponding semiconductor modules66in a PWM control mode using a given carrier frequency. The switching operations usually generate electromagnetic noise against which the housing30, the rotor40, and the stator50which are arranged outside the electrical components62shield. Further, at least a portion of the semiconductor modules66is arranged inside the region surrounded by the stator core52located radially outside the cylinder71of the casing64, thereby minimizing adverse effects of magnetic flux generated by the semiconductor modules66on the stator coil51as compared with a case where the semiconductor modules66and the stator coil51are arranged without the stator core52interposed therebetween. The magnetic flux created by the stator coil51also hardly affects the semiconductor modules66. It is more effective that the whole of the semiconductor modules66are located in the region surrounded by the stator core52disposed radially outside the cylinder71of the casing64. When at least a portion of the semiconductor modules66may be surrounded by the coolant path74, it offers a beneficial advantage that the heat produced by the stator coil51or the magnet unit42is prevented from reaching the semiconductor modules66. The cylinder71has through-holes78which are formed near the end plate63and through which the wiring members79(seeFIG.2) respectively pass to electrically connect the stator50disposed outside the cylinder71and the electrical components62arranged inside the cylinder71. The wiring members79, as illustrated inFIG.2, connect with ends of the stator coil51and with the bus bars76cof the wiring module76using crimping or welding techniques. The wiring members79are implemented by, for example, bus bars whose joining surfaces are preferably flattened. A single through-hole78or a plurality of through-holes78are preferably provided. This embodiment has two through-holes78. The use of the two through-holes78facilitates the ease with which terminals extending from the two sets of the three-phase windings are connected by the wiring members79, and is suitable for achieving multi-phase wire connections. The rotor40and the stator50are, as described already inFIG.4, arranged within the housing30in this order in a radially inward direction. The inverter unit60is arranged radially inside the stator50. If a radius of the inner periphery of the housing30is defined as d, the rotor40and the stator50are located radially outside a distance of d×0.705 away from the center of rotation of the rotor40. If a region located radially inside the inner periphery of the stator50(i.e., the inner circumferential surface of the stator core52) is defined as a first region X1, and a region radially extending from the inner periphery of the stator50to the housing30is defined as a second region X2, an area of a transverse section of the first region X1is set greater than that of the second region X2. As viewed in a region where the magnet unit42of the rotor40overlaps the stator coil51, the volume of the first region X1is larger than that of the second region X2. The rotor40and the stator50are fabricated as a magnetic circuit component assembly. In the housing30, the first region X1, which is located radially inside the inner peripheral surface of the magnetic circuit component assembly, is larger in volume than the region X2, which lies between the inner peripheral surface of the magnetic circuit component assembly and the housing30in the radial direction. Next, the structures of the rotor40and the stator50will be described below in more detail. Typical rotating electrical machines are known which are equipped with a stator with an annular stator core; the annular stator core is made of a stack of steel plates. The stator has stator windings wound in a plurality of slots arranged in a circumferential direction of the stator core. Specifically, the stator core has teeth each extending in a corresponding radial direction thereof at a corresponding given interval away from a yoke. Each slot is formed between a corresponding pair of two radially adjacent teeth. In each slot, a plurality of conductors are arranged in the radial direction in the form of layers to form the stator windings. However, the above stator structure has a possibility that, when stator windings are energized, an increase in magnetomotive force based on the energized stator windings may result in magnetic saturation in the teeth of the stator core, thereby restricting torque density in the rotating electrical machine. In other words, rotational flux, as created by the energization of the stator windings of the stator core, may concentrate on the teeth, resulting in a possibility of causing magnetic saturation. Generally, IPM (Interior Permanent Magnet) rotors are known to have a structure in which permanent magnets are arranged on a d-axis of a d-q axis coordinate system in a rotor core, and a portion of the rotor core is placed on a q-axis of the d-q axis coordinate system. Excitation of a stator winding near the d-axis causes an excited magnetic flux to flow from a stator to a rotor according to Fleming's rules. This causes magnetic saturation to occur widely in the rotor core on the q-axis. FIG.7is a graphic torque diagram which demonstrates a relationship between an ampere-turn (AT) representing a magnetomotive force created by a stator winding and a torque density (Nm/L). A broken line indicates characteristics of a typical IPM rotor-rotating electrical machine.FIG.7shows that, in the typical rotating electrical machine, an increase in magnetomotive force in a stator will cause magnetic saturation to occur at two places; one of the two places is each tooth between the corresponding adjacent pair of slots, and the other thereof is a q-axis core, which is a portion of the rotor core on the q-axis. This may result in a restriction of an increase in torque. In this way, a design value of the ampere-turn is restricted at A1in the typical rotating electrical machine. In order to alleviate the above problem in this embodiment, the rotating electrical machine10is designed to have an additional structure, as will be described below, which aims to eliminate the restriction arising from the magnetic saturation. Specifically, as a first measure, the stator50is designed to have a slot-less structure for eliminating the magnetic saturation occurring in the teeth of the stator core of the stator and also to use an SPM (Surface Permanent Magnet) rotor for eliminating the magnetic saturation occurring in a q-axis core of the IPM rotor. The first measure serves to eliminate the above-described two places where the magnetic saturation occurs, but however, may result in a decrease in torque in a low-current region (see an alternate long and short dash line inFIG.7). For alleviating this problem, as a second measure, the rotating electrical machine10employs a polar anisotropic structure to increase a magnetic path of magnets in the magnet unit42of the rotor40to thereby enhance a magnetic force. This will result in an increase in a magnetic flux in the SPM rotor to minimize the torque decrease. Additionally, as a third measure, the rotating electrical machine10employs a flattened conductor structure to decrease a thickness of conductors of the coil side portion53of the stator coil51in the radial direction of the stator50for compensating for the torque decrease. The above magnetic force-enhanced polar anisotropic structure would result in a flow of large eddy current in the stator coil51facing the magnet unit42. From this viewpoint, the third measure is to employ the flattened conductor structure in which the conductors have a decreased thickness in the radial direction, thereby minimizing the generation of the eddy current in the stator coil51in the radial direction. The above first to third structures are, as indicated by a solid line inFIG.7, expected to greatly improve the torque characteristics using high magnetic, i.e. strong, magnets and also alleviate a risk of generation of a large eddy current resulting from the use of the high strength magnets. Additionally, as a fourth measure, the rotating electrical machine10employs a magnet unit, which has a polar anisotropic structure to create a magnetic density distribution approximating a sine wave. This increases a sine wave matching percentage using pulse control, as will be described later, to thereby enhance the torque and also results in a moderate change in magnetic flux, thereby minimizing an eddy-current loss (i.e., a copper loss caused by eddy current) as compared with radial magnets. The sine wave matching percentage will be described below. The sine wave matching percentage may be derived by comparing a waveform, a cycle, and a peak value of a surface magnetic flux density distribution measured by actually moving a magnetic flux probe on a surface of a magnet with those of a sine wave. The since wave matching percentage is given by a percentage of an amplitude of a primary waveform that is a waveform of a fundamental wave in a rotating electrical machine to that of the actually measured waveform, that is, an amplitude of the sum of the fundamental wave and harmonic components. An increase in the sine wave matching percentage will cause the waveform in the surface magnetic flux density distribution to approach the waveform of the sine wave. When an electrical current of a primary sine wave is delivered by an inverter to a rotating electrical machine equipped with magnets having an improved sine wave matching percentage, it will cause a large degree of torque to be produced, combined with the fact that the waveform in the surface magnetic flux density distribution of the magnet is close to the waveform of a sine wave. The surface magnetic flux density distribution may alternatively be derived using electromagnetic analysis according to Maxwell's equations. As a fifth measure, the stator coil51is designed to have a conductor strand structure made of a bundle of wires. In the conductor strand structure of the stator coil51, the wires are connected parallel to each other, thus enabling a high current or large amount of current to flow in the stator coil51and also minimizing an eddy current occurring in the conductors widened in the circumferential direction of the stator50more effectively than the third measure in which the conductors are flattened in the radial direction because each of the wires has a decreased transverse sectional area. The use of the bundle of the wires will cancel an eddy current arising from magnetic flux occurring according to Ampere's circuital law in response to the magnetomotive force produced by the conductors. The use of the fourth and fifth measures minimizes the eddy-current loss resulting from the high magnetic force produced by the high-magnetic force magnets provided by the second measure and also enhance the torque. The slot-less structure of the stator50, the flattened conductor structure of the stator coil51, and the polar anisotropic structure of the magnet unit42will be described below. The slot-less structure of the stator50and the flattened conductor structure of the stator coil51will first be discussed.FIG.8is a transverse sectional view illustrating the rotor40and the stator50.FIG.9is a partially enlarged view illustrating the rotor40and the stator50inFIG.8.FIG.10is a transverse sectional view of the stator50taken along the line X-X inFIG.11.FIG.11is a longitudinal sectional view of the stator50.FIG.12is a perspective view of the stator coil51.FIGS.8and9indicate directions of magnetization of magnets of the magnet unit42using arrows. The stator core52has, as clearly illustrated inFIGS.8to11, a cylindrical shape and is comprised of a plurality of magnetic steel plates stacked in the axial direction of the stator core52to have a given thickness in a radial direction of the stator core52. The stator coil51is mounted on the outer periphery of the stator core52which faces the rotor40. The outer peripheral surface of the stator core52facing the rotor40serves as a conductor mounting portion (i.e., a conductor area). The outer peripheral surface of the stator core52is shaped as a curved surface without any irregularities. A plurality of conductor groups81are arranged on the outer peripheral surface of the stator core52at given intervals away from each other in the circumferential direction of the stator core52. The stator core52functions as a back yoke that is a portion of a magnetic circuit working to rotate the rotor40. The stator50is designed to have a structure in which no tooth (i.e., no portion of a core) made of a soft magnetic material is disposed between each pair of adjacent conductor groups81in the circumferential direction (i.e., the slot-less structure). In this embodiment, a resin material of the sealing member57is disposed in the space or gap56between each pair of adjacent conductor groups81. In other words, the stator50has a conductor-to-conductor member, i.e., an inter-conductor member, which is disposed between the conductor groups81arranged adjacent each other in the circumferential direction of the stator50and made of a non-magnetic material. The conductor-to-conductor members serve as the sealing members57. Before the sealing members57are placed to seal the gaps56, the conductor groups81are arranged in the circumferential direction radially outside the stator core52at a given interval away from each other through the gaps56that are conductor-to-conductor regions. This makes up the slot-less structure of the stator50. In other words, each of the conductor groups81is, as described later in detail, made of two conductors82. An interval between a respective two of the conductor groups81arranged adjacent each other in the circumferential direction of the stator50is occupied only by a non-magnetic material. The non-magnetic material, as referred to herein, includes a non-magnetic gas, such as air, or a non-magnetic liquid. In the following discussion, the sealing members57will also be referred to as conductor-to-conductor members. The structure, as referred to herein, in which each of the teeth is disposed between the corresponding adjacent pair of the conductor groups81arrayed in the circumferential direction means that each of the teeth has a given thickness in the radial direction and a given width in the circumferential direction of the stator50, so that a portion of the magnetic circuit, that is, a magnet magnetic path, lies between each adjacent pair of the conductor groups81. In contrast, the structure in which no tooth lies between the adjacent conductor groups81means that there is no magnetic circuit between each adjacent pair of the conductor groups81. The stator coil (i.e., an armature coil)51, as illustrated inFIG.10, has a given thickness T2(which will also be referred to below as a first dimension) and a width W2(which will also be referred to below as a second dimension). The thickness T2is given by a minimum distance between an outer side surface and an inner side surface of the stator coil51which are opposed to each other in the radial direction of the stator50. The width W2is given by a dimension of a portion of the stator coil51which functions as one of multiple phases (i.e., the U-phase, the V-phase, the W-phase, the X-phase, the Y-phase, and the Z-phase in this embodiment) of the stator coil51in the circumferential direction. Specifically, in a case where one adjacent pair of the conductor groups81in the circumferential direction inFIG.10serves as a corresponding one of the three phases, for example, the U-phase winding, a distance between circumferentially outermost ends of the conductor groups81of the circumferentially adjacent pair of the conductor groups81is the width W2. The thickness T2is smaller than the width W2. The thickness T2is preferably set smaller than the sum of widths of the two conductor groups81within the width W2. If the stator coil51(more specifically, the conductor82) is designed to have a true circular transverse section, an oval transverse section, or a polygonal transverse section, the cross section of the conductor82taken in the radial direction of the stator50may be shaped to have a maximum dimension W12in the radial direction of the stator50and a maximum dimension W11in the circumferential direction of the stator50. The stator coil51is, as can be seen inFIGS.10and11, sealed by the sealing members57which are formed by a synthetic resin mold. Specifically, the stator coil51and the stator core52are put in a mold together when the sealing members57are molded by the resin. The resin may be considered as a non-magnetic material or an equivalent thereof whose Bs (saturation magnetic flux density) is zero. As shown in the transverse section inFIG.10, the sealing members57are provided by placing synthetic resin in the gaps56between the conductor groups81. The sealing members57serve as insulators arranged between the conductor groups81. In other words, each of the sealing members57functions as an insulator in one of the gaps56. The sealing members57occupy a region which is located radially outside the stator core52, and includes all the conductor groups81, in other words, which is defined to have a thickness dimension larger than that of each of the conductor groups81in the radial direction. As shown in the longitudinal section inFIG.11, the sealing members57lie to occupy a region including the turns84of the stator coil51. Radially inside the stator coil51, the sealing members57lie in a region including at least a portion of the axially opposed ends of the stator core52. In this case, the stator coil51is fully sealed by the resin except for the ends of each phase winding, i.e., terminals joined to the inverter circuits. The structure in which the sealing members57are disposed in the region including the ends of the stator core52enables the sealing members57to compress the stack of the steel plates of the stator core52inwardly in the axial direction. In other words, the sealing members57work to firmly retain the stack of the steel plates of the stator core52. In this embodiment, the inner peripheral surface of the stator core52is not sealed using resin, but however, the whole of the stator core52including the inner peripheral surface may be sealed using resin. In a case where the rotating electrical machine10is used as a power source for a vehicle, the sealing members57are preferably made of a high heat-resistance fluororesin, epoxy resin, PPS resin, PEEK resin, LCP resin, silicone resin, PAI resin, or PI resin. In terms of a linear coefficient expansion to minimize breakage of the sealing members57due to an expansion difference, the sealing members57are preferably made of the same material as that of an outer film of the conductors of the stator coil51. A silicone resin whose linear coefficient expansion is twice or more those of other resins is preferably excluded from the material of the sealing members57. In a case of electrical products, such as electric vehicles equipped with no combustion engine, PPO resin, phenol resin, or FRP resin which resists 180° C. may be used. Other resin materials can be used in fields where an ambient temperature of the rotating electrical machine is expected to be lower than 100° C. The degree of torque outputted by the rotating electrical machine10is usually proportional to the degree of magnetic flux. In a case where a stator core is equipped with teeth, a maximum amount of magnetic flux in the stator core is restricted depending upon the saturation magnetic flux density in the teeth, while in a case where the stator core is not equipped with teeth, the maximum amount of magnetic flux in the stator core is not restricted. Such a structure is, therefore, useful for increasing an amount of electrical current delivered to the stator coil51to increase the degree of torque produced by the rotating electrical machine10. This embodiment employs the slot-less structure in which the stator50is not equipped with teeth, thereby resulting in a decrease in inductance of the stator50. Specifically, a stator of a typical rotating electrical machine in which conductors are disposed in slots isolated by teeth from each other has an inductance of approximately 1 mH, while the stator50in this embodiment has a decreased inductance of 5 to 60 pH. The rotating electrical machine10in this embodiment is of an outer rotor type, but has a decreased inductance of the stator50to decrease a mechanical time constant Tm. In other words, the rotating electrical machine10is capable of outputting a high degree of torque and designed to have a decreased value of the mechanical time constant Tm. If inertia is defined as J, inductance is defined as L, torque constant is defined as Kt, and back electromotive force constant is defined as Ke, the mechanical time constant Tm is calculated according to the equation of Tm=(J×L)/(Kt×Ke). This shows that a decrease in inductance L will result in a decrease in mechanical time constant Tm. Each of the conductor groups81arranged radially outside the stator core52is made of a plurality of conductors82whose transverse section is of a flattened rectangular shape and which are disposed on one another in the radial direction of the stator core52. Each of the conductors82is oriented to have a transverse section meeting a relation of radial dimension<circumferential dimension. This causes each of the conductor groups81to be thin in the radial direction. A conductive region of the conductor group81also extends inside a region occupied by teeth of a typical stator. This creates a flattened conductive region structure in which a sectional area of each of the conductors82is increased in the circumferential direction, thereby alleviating a possibility that the amount of thermal energy may be increased by a decrease in sectional area of a conductor arising from flattening of the conductor. A structure in which a plurality of conductors are arranged in the circumferential direction and connected in parallel to each other is usually subjected to a decrease in sectional area of the conductors by a thickness of a coated layer of the conductors, but however, has beneficial advantages obtained for the same reasons as described above. In the following discussion, each of the conductor groups81or each of the conductors82will also be referred to as a conductive member. The stator50in this embodiment is, as described already, designed to have no slots, thereby enabling the stator coil51to be designed to have a conductive region of an entire circumferential portion of the stator50which is larger in size than a non-conductive region unoccupied by the stator coil51in the stator50. In typical rotating electrical machines for vehicles, a ratio of the conductive region/the non-conductive region is usually one or less. In contrast, this embodiment has the conductor groups81arranged to have the conductive region substantially identical in size with or larger in size than the non-conductive region. If the conductor region, as illustrated inFIG.10, occupied by the conductor82(i.e., the straight section83which will be described later in detail) in the circumferential direction is defined as WA, and a conductor-to-conductor region that is an interval between a respective adjacent two of the conductors82is defined as WB, the conductor region WA is larger in size than the conductor-to-conductor region WB in the circumferential direction. The conductor group81of the stator coil51has a thickness in the radial direction thereof which is smaller than a circumferential width of a portion of the stator coil51which lies in a region of one magnetic pole and serves as one of the phases of the stator coil51. In the structure in which each of the conductor groups81is made up of the two conductors82stacked in the form of two layers lying on each other in the radial direction, and the two conductor groups81are arranged in the circumferential direction within a region of one magnetic pole for each phase, a relation of Tc×2<Wc×2 is met where Tc is the thickness of each of the conductors82in the radial direction, and Wc is the width of each of the conductors82in the circumferential direction. In another structure in which each of the conductor groups81is made up of the two conductors82, and each of the conductor groups81lies within the region of one magnetic pole for each phase, a relation of Tc×2<Wc is preferably met. In other words, in the stator coil51which is designed to have conductor portions (i.e., the conductor groups81) arranged at a given interval away from each other in the circumferential direction, the thickness of each conductor portion (i.e., the conductor group81) in the radial direction is set smaller than the width of a portion of the stator coil51lying in the region of one magnetic pole for each phase in the circumferential direction. In other words, each of the conductors82is preferably shaped to have the thickness Tc in the radial direction which is smaller than the width Wc in the circumferential direction. The thickness 2Tc of each of the conductor groups81each made of a stack of the two conductors82in the radial direction is preferably smaller than the width Wc of each of the conductor groups81in the circumferential direction. The degree of torque produced by the rotating electrical machine10is substantially inversely proportional to the thickness of the stator core52in the radial direction. The conductor groups81arranged radially outside the stator core52are, as described above, designed to have the thickness decreased in the radial direction. This design is useful in increasing the degree of torque outputted by the rotating electrical machine10. This is because a distance between the magnet unit42of the rotor40and the stator core52(i.e., a distance in which there is no iron) may be decreased to decrease the magnetic resistance. This enables interlinkage magnetic flux in the stator core52produced by the permanent magnets to be increased to enhance the torque. The decrease in thickness of the conductor groups81facilitates the ease with which a magnetic flux leaking from the conductor groups81is collected in the stator core52, thereby preventing the magnetic flux from leaking outside the stator core52without being used for enhancing the torque. This avoids a drop in magnetic force arising from the leakage of the magnetic flux and increases the interlinkage magnetic flux in the stator core52produced by the permanent magnets, thereby enhancing the torque. Each of the conductors82is made of a coated conductor formed by covering the surface of the conductor body82awith the coating82b. The conductors82stacked on one another in the radial direction are, therefore, insulated from each other. Similarly, the conductors82are insulated from the stator core52. The insulating coating82bmay be a coating of each wire86, as will be described later in detail, in a case where each wire86is made of wire with a self-bonded coating or may be made by an additional insulator disposed on a coating of each wire86. Each phase winding made of the conductors82is insulated by the coating82bexcept an exposed portion thereof for joining purposes. The exposed portion includes, for example, an input or an output terminal or a neutral point in a case of a star connection. The conductor groups81arranged adjacent each other in the radial direction are firmly adhered to each other using resin or self-bonding coated wire, thereby minimizing a possibility of insulation breakdown, mechanical vibration, or noise caused by rubbing of the conductors82. In this embodiment, the conductor body82ais made of a collection of a plurality of wires86. Specifically, the conductor body82ais, as can be seen inFIG.13, made of a strand of the wires86each being twisted. Each of the wires86is, as can be seen inFIG.14, made of a bundle of a plurality of thin conductive fibers87. For instance, each of the wires86is made of a complex of CNT (carbon nanotube) fibers. The CNT fibers include boron-containing microfibers in which at least a portion of carbon is substituted with boron. Instead of the CNT fibers that are carbon-based microfibers, vapor grown carbon fiber (VGCF) may be used, but however, the CNT fiber is preferable. The surface of the wire86is covered with a layer of insulating polymer, such as enamel. The surface of the wire86is preferably covered with an enamel coating, such as polyimide coating or amide-imide coating. The conductors82constitute n-phase windings of the stator coil51. The wires86of each of the conductors82, i.e., the conductor body82aof each of the conductors82, are placed in contact with each other. Each of the conductors82has one or more portions which are formed by twisting the wires86and define one or more portions of a corresponding one of the phase-windings. A resistance value between the twisted wires86is larger than that of each of the wires86. In other words, the respective adjacent two wires86have a first electrical resistivity in a direction in which the wires86are arranged adjacent each other. Each of the wires86has a second electrical resistivity in a lengthwise direction of the wire86. The first electrical resistivity is larger than the second electrical resistivity. Each of the conductors82may be made of an assembly of wires, i.e., the twisted wires86covered with insulating members whose first electrical resistivity is very high. The conductor body82aof each of the conductors82is made of a strand of the twisted wires86. The conductor body82ais, as described above, made of the twisted wires86, thereby reducing an eddy current created in each of the wires86, which reduces an eddy current in the conductor body82a. Each of the wires86is twisted, thereby causing each of the wires86to have portions where directions of applied magnetic field are opposite each other, which cancels a back electromotive force. This results in a reduction in the eddy current. Particularly, each of the wires86is made of the conductive fibers87, thereby enabling the conductive fibers87to be thin and also enabling the number of times the conductive fibers87are twisted to be increased, which enhances the reduction in eddy current. How to insulate the wires86from each other is not limited to the above-described use of the polymer insulating layer, but the contact resistance may be used to resist a flow of current between the wires86. In other words, the above beneficial advantage is obtained by a difference in potential arising from a difference between the resistance between the twisted wires86and the resistance of each of the wires86as long as the resistance between the wires86is larger than that of each of the wires86. For instance, the contact resistance may be increased by using production equipment for the wires86and production equipment for the stator50(i.e., an armature) of the rotating electrical machine10as discrete devices to cause the wires86to be oxidized during a transport time or a work interval. Each of the conductors82is, as described above, of a low-profile or flattened rectangular shape in cross section. The conductors82are arranged in the radial direction. Each of the conductors82is made of a strand of the wires86each of which is formed by a self-bonding coating wire equipped with, for example, a fusing or bonding layer or an insulating layer and which are twisted with the bonding layers fused together. Each of the conductors82may alternatively be made by forming twisted wires with no bonding layer or twisted self-bonding coating wires into a desired shape using synthetic resin. The insulating coating82bof each of the conductors82may have a thickness of 80 μm to 100 μm which is larger than that of a coating of typical wire (i.e., 5 μm to 40 μm). In this case, a required degree of insulation between the conductors82is achieved even if no insulating sheet is interposed between the conductors82. It is also advisable that the insulating coating82bbe higher in degree of insulation than the insulating layer of the wire86to achieve insulation between the phase windings. For instance, the polymer insulating layer of the wire86has a thickness of, for example, 5 μm. In this case, the thickness of the insulating coating82bof the conductor82is preferably selected to be 80 μm to 100 μm to achieve the insulation between the phase windings. Each of the conductors82may alternatively be made of a bundle of the untwisted wires86. In brief, each of the conductors82may be made of a bundle of the wires86whose entire lengths are twisted, whose portions are twisted, or whose entire lengths are untwisted. Each of the conductors82constituting the conductor portion is, as described above, made of a bundle of the wires86. The resistance between the wires86is larger than that of each of the wires86. The conductors82are each bent and arranged in a given pattern in the circumferential direction of the stator coil51, thereby forming the phase-windings of the stator coil51. The stator coil51, as illustrated inFIG.12, includes the coil side portion53and the coil ends54and55. The conductors82have the straight sections83which extend straight in the axial direction of the stator coil51and form the coil side portion53. The conductors82have the turns84which are arranged outside the coil side portion53in the axial direction and form the coil ends54and55. Each of the conductor82is made of a wave-shaped string of conductor formed by alternately arranging the straight sections83and the turns84. The straight sections83are arranged to face the magnet unit42in the radial direction. The straight sections83are arranged at given intervals away from one another and joined together using the turns84located outside the magnet unit42in the axial direction. The straight sections83correspond to a magnet facing portion. In this embodiment, the stator coil51is shaped in the form of an annular distributed coil. In the coil side portion53, the straight sections83are arranged at intervals away from one another for each phase; each of the intervals corresponds to a corresponding pole pair of the magnet unit42. In each of the coil ends54and55, the straight sections83for each phase are joined together by the turns84, each of which is of a V-shape. The straight sections83, which are paired for each pole pair, are opposite to each other in a direction of flow of electrical current. Combination of pairs of straight sections83, each joined together by a corresponding turn84, in the coil end53is different from combination of pairs of straight sections83, each joined together by a corresponding turn84, in the coil end54. The joints of the straight sections83by the turns84are arranged in the circumferential direction on each of the coil ends54and55to complete the stator winding in a hollow cylindrical shape. More specifically, the stator coil51is made up of two pairs of the conductors82for each phase. The stator coil51is equipped with a first three-phase winding set including the U-phase winding, the V-phase winding, and the W-phase winding and a second three-phase phase winding set including the X-phase winding, the Y-phase winding, and the Z-phase winding. The first three-phase winding set and the second three-phase winding set are arranged adjacent each other in the radial direction in the form of two layers. If the number of phases of the stator coil51is defined as S (i.e., 6 in this embodiment), the number of the conductors82for each phase is defined as m, 2×S×m=2Sm conductors82are used for each pole pair in the stator coil51. The rotating electrical machine in this embodiment is designed so that the number of phases S is 6, the number m is 4, and 8 pole pairs are used. 6×4×8=192 conductors82are arranged in the circumferential direction of the stator core52. The stator coil51inFIG.12is designed to have the coil side portion53which has the straight sections82arranged in the form of two overlapping layers disposed adjacent each other in the radial direction. Each of the coil ends54and55has a respective two of the turns84which extend from the radially overlapping straight sections82in opposite circumferential directions. In other words, the conductors82arranged adjacent each other in the radial direction are opposite to each other in direction in which the turns84extend except for ends of the stator coil51. A winding structure of the conductors82of the stator coil51will be described below in detail. In this embodiment, the conductors82formed in the shape of a wave winding are arranged in the form of a plurality of layers (e.g., two layers) disposed adjacent or overlapping each other in the radial direction. FIGS.15(a) and15(b)illustrate the layout of the conductors82which form the nthlayer.FIG.15(a)shows the configuration of the conductors82, as the side of the stator coil51is viewed.FIG.15(b)shows the configuration of the conductors82as viewed in the axial direction of the stator coil51. InFIGS.15(a) and15(b), locations of the conductor groups81are indicated by symbols D1, D2, D3. . . , and D9. For the sake of simplicity of disclosure,FIGS.15(a) and15(b)show only three conductors82which will be referred to herein as the first conductor82_A, the second conductor82_B, and the third conductor82_C. The conductors82_A to82_C have the straight sections83arranged at a location of the nthlayer, in other words, at the same position in the radial direction. Every two of the straight sections82which are arranged at6pitches (corresponding to 3×m pairs) away from each other in the circumferential direction are joined together by one of the turns84. In other words, in each of the conductors82_A to82_C, the outermost two straight sections of the seven straight sections83arranged in the circumferential direction of the stator coil51on the same circle defined about the center of the rotor40are joined together using one of the turns84. For instance, in the first conductor82_A, the straight sections83placed at the respective locations D1and D7are joined together by the inverse V-shaped turn84. The conductor82_B is arranged at the same location of the nthlayer to be circumferentially shifted by one pitch relative to the conductor82_A, and the conductor82_C is arranged at the same location of the nthlayer to be circumferentially shifted by one pitch relative to the conductor82_B. In this layout, the conductors82_A to82_C are placed at a location of the same layer, thereby resulting in a possibility that the turns84thereof might physically interfere with each other. In order to alleviate such a possibility, each of the turns84of the conductors82_A to82_C in this embodiment is shaped to have an interference avoiding portion formed by offsetting a portion of the corresponding turn84in the radial direction. Specifically, the turn84of each of the conductors82_A to82_C includes a slant portion84a, a head portion84b, a slant portion84c, and a return portion84d. The slant portion84aextends in the circumferential direction of the same circle (which will also be referred to as a first circle). The head portion84extends from the slant portion84aradially inside the first circle (i.e., upward inFIG.15(b)) to reach another circle (which will also be referred to as a second circle). The slant portion84cextends in the circumferential direction of the second circle. The return portion84dreturns from the second circle back to the first circle. The head portion84b, the slant portion84c, and the return portion84ddefine the interference avoiding portion. The slant portion84cmay be arranged radially outside the slant portion84a. In other words, each of the conductors82_A to82_C has the turn84shaped to have the slant portion84aand the slant portion84cwhich are arranged on opposite sides of the head portion84bat the center in the circumferential direction. The locations of the slant portions84aand84bare different from each other in the radial direction (i.e., a direction perpendicular to the drawing ofFIG.15(a)or a vertical direction inFIG.15(b)). For instance, the turn84of the first conductor82_A is shaped to extend from the location D1on the nthlayer in the circumferential direction, be bent at the head portion84bthat is the center of the circumferential length of the turn84in the radial direction (e.g., radially inwardly), be bent again in the circumferential direction, extend again in the circumferential direction, and then be bent at the return portion84din the radial direction (e.g., radially outwardly) to reach the location D7on the nthlayer. With the above arrangements, the slant portions84aof the conductors82_A to82_C are arranged vertically or downward in the order of the first conductor82_A, the second conductor82_B, and the third conductor82_C. The head portions84bchange the order of the locations of the conductors82_A to82_C in the vertical direction, so that the slant portions84care arranged vertically or downward in the order of the third conductor82_C, the second conductor82_B, and the first conductor82_A. This layout achieves an arrangement of the conductors82_A to82_C in the circumferential direction without any physical interference with each other. In the structure wherein the conductors82are laid to overlap each other in the radial direction to form the conductor group81, the turns84leading to a radially innermost one and a radially outermost one of the straight sections83forming the two or more layers are preferably located radially outside the straight sections83. In a case where the conductors83forming the two or more layers are bent in the same radial direction near boundaries between ends of the turns84and the straight sections83, the conductors83are preferably shaped not to deteriorate the insulation therebetween due to physical interference of the conductors83with each other. In the example ofFIGS.15(a) and15(b), the conductors82laid on each other in the radial direction are bent radially at the return portions84dof the turns84at the location D7to D9. It is advisable that the conductor82of the nthlayer and the conductor82of the n+1thlayer be bent, as illustrated inFIG.16, at radii of curvature different from each other. Specifically, the radius of curvature R1of the conductor82of the nthlayer is preferably selected to be smaller than the radius of curvature R2of the conductor82of the n+1thlayer. Additionally, radial displacements of the conductor82of the nthlayer and the conductor82of the n+1thlayer are preferably selected to be different from each other. If the amount of radial displacement of the conductor82of the nthlayer is defined as S1, and the amount of radial displacement of the conductor82of the n+1thlayer located radially outside the nth layer defined as S2, the amount of radial displacement S1is preferably selected to be greater than the amount of radial displacement S2. The above layout of the conductors82eliminates the risk of interference with each other, thereby ensuring a required degree of insulation between the conductors82even when the conductors82laid on each other in the radial direction are bent in the same direction. The structure of the magnet unit42of the rotor40will be described below. In this embodiment, the magnet unit42is made of permanent magnets in which a remanent flux density Br=1.0 T, and an intrinsic coercive force Hcj=400 kA/m. The permanent magnets used in this embodiment are implemented by sintered magnets formed by sintering grains of magnetic material and compacting them into a given shape and have the following specifications. The intrinsic coercive force Hcj on a J-H curve is 400 kA/m or more. The remanent flux density Br on the J-H curve is 1.0 T or more. Selected magnets, each of which is designed so that, when 5,000 to 10,000 AT is applied thereto by phase-to-phase excitation, a magnetic distance between paired poles, i.e., between an N-pole and an S-pole, in the corresponding magnet has a length of 25 mm, may be used as the magnets of the present embodiment. The magnetic distance between paired poles represents a path in which a magnetic flux flows. Each of the selected magnets can meet a relation of Hcj=10000 A without becoming demagnetized. In other words, the magnet unit42is engineered so that a saturation magnetic flux density Js is 1.2 T or more, a grain size is 10 μm or less, and a relation of Js×a≥1.0 T is met where a is an orientation ratio. The magnet unit42will be additionally described below. The magnet unit42(i.e., magnets) has a feature that Js meets a relation of 2.15 T≥Js≥1.2 T. In other words, magnets used in the magnet unit42may be FeNi magnets having a NdFe11 TiN, Nd2Fe14B, Sm2Fe17N3, or L10 crystals. Note that samarium-cobalt magnets, such as SmCo5, FePt, Dy2Fe14B magnet, or CoPt magnets cannot be used. When magnets in which high Js characteristics of neodymium are slightly lost, but a high degree of coercive force of Dy is ensured using the heavy rare earth dysprosium, like in homotopic compounds, such as Dy2Fe14B and Nd2Fe14B, which may meet a relation of 2.15 T≥Js≥1.2 T, they may be used in the magnet unit42. Such a type of magnet will also be referred to herein as [Nd1-xDyx]2Fe14B]. Further, a magnet contacting different types of compositions, in other words, a magnet made from two or more types of materials, such as FeNi and Sm2Fe17N3, may be used to meet a relation of 2.15 T≤Js≥1.2 T. A mixed magnet made by adding a small amount of, for example, Dy2Fe14B in which Js<1 T to an Nd2Fe14B magnet in which Js=1.6 T, meaning that Js is sufficient to enhance the coercive force, may also be used to meet a relation of 2.15 T≤Js≤1.2 T. In use of the rotating electrical machine at a temperature outside a temperature range of human activities which is higher than, for example, 60° C. exceeding temperatures of deserts, for example, within a passenger compartment of a vehicle where the temperature may rise to 80° C. in summer, the magnet preferably contains FeNi or Sm2Fe17N3 components which are less dependent on temperature. This is because motor characteristics are greatly changed by temperature-dependent factors thereof in motor operations within a range of approximately −40° which is within a range experienced by societies in Northern Europe to 60° C. or more experienced in desert regions or at 180 to 240° C. that is a heat resistance temperature of the enamel coating, which leads to a difficulty in achieving a required control operation using the same motor driver. The use of FeNi containing the above-described L10 crystals or Sm2Fe17N3 magnets will result in a decrease in load on the motor driver because characteristics thereof have temperature-dependent factors lower than half that of Nd2Fe14B magnets. Additionally, the magnet unit42is engineered to use the above-described magnet mixing so that a particle size of fine powder before being magnetically oriented is lower than or equal to 10 μm and higher than or equal to a size of single-domain particles. The coercive force of a magnet is usually increased by decreasing the size of powered particles thereof to a few hundred nm. In recent years, the smallest possible particles have been used. If the particles of the magnet are too small, the BHmax (i.e., the maximum energy product) of the magnet will be decreased due to oxidization thereof. It is, thus, preferable that the particle size of the magnet is higher than or equal to the size of single-domain particles. The particle size being only up to the size of single-domain particles is known to increase the coercive force of the magnet. The particle size, as referred to herein, refers to the diameter or size of fine powdered particles in a magnetic orientation operation in production processes of magnets. The magnet unit42includes a first magnet91and a second magnet92. Each of the first magnet91and the second magnet92of the magnet unit42is made of a sintered magnet formed by firing or heating magnetic powder at high temperatures and compacting it. The sintering is achieved so as to meet the conditions where the saturation magnetization Js of the magnet unit42is 1.2 T (Tesla) or more, the particle size of the first magnet91and the second magnet92is 10 μm or less, and Js×a is higher than or equal to 1.0 T (Tesla) where a is an orientation ratio. Each of the first magnet91and the second magnet92is also sintered to meet the following conditions. By performing the magnetic orientation in the magnetic orientation operation in the production processes of the first magnet91and the second magnet92, the first and second magnets91and92have an orientation ratio different to the definition of orientation of magnetic force in a magnetization operation for isotropic magnets. The magnet unit42in this embodiment is designed to have(1) The saturation magnetization Js more than or equal to 1.2 T(2) The high orientation ratio a of each of the first magnet91and the second magnet92meeting a relation of Jr≥Js×a≥1.0 T The orientation ratio a, as referred to herein, is defined in the following way. If each of the first magnet91and the second magnet92has six easy axes of magnetization, five of the easy axes of magnetization are oriented in the same direction A10, and the remaining one of the easy axes of magnetization is oriented in the direction B10angled at 90 degrees to the direction A10, then a relation of a=⅚ is met. Alternatively, if each of the first magnet91and the second magnet92has six easy axes of magnetization, five of the easy axes of magnetization are oriented in the same direction A10, and the remaining one of the easy axes of magnetization is oriented in the direction B10angled at 45 degrees to the direction A10, then a relation of a=(5+0.707)/6 is met since a component oriented in the direction A10is expressed by cos 450=0.707. The first magnet91and the second magnet92in this embodiment are, as described above, each made using sintering techniques, but however, they may be produced in another way as long as the above conditions are satisfied. For instance, a method of forming an MQ3 magnet may be used. This embodiment uses permanent magnets, each of which is magnetically oriented to have a controlled easy axis of magnetization thereof, thereby enabling a magnetic circuit length within the corresponding one of the magnets to be longer than that within a typical linearly oriented magnet which produces a magnetic flux density of 1.0 T or more. In other words, this embodiment enables the magnetic circuit length for one pole pair in the magnets in this embodiment to be achieved using magnets each with a smaller volume. Additionally, a range of reversible flux loss in the magnets is not lost when subjected to severe high temperatures, as compared with use of typical linearly oriented magnets. The disclosers or inventors of this application have found that characteristics similar to those of anisotropic magnets are obtained even using prior art magnets. The easy axis of magnetization represents a crystal orientation in which a crystal is easy to magnetize in a magnet. The orientation of the easy axis of magnetization in the magnet, as referred to herein, is a direction in which an orientation ratio is 50% or more where the orientation ratio indicates the degree to which easy axes of magnetization of crystals are aligned with each other or a direction of an average of magnetic orientations in the magnet. The magnet unit42is, as clearly illustrated inFIGS.8and9, of an annular shape and arranged inside the magnet holder41(specifically, radially inside the cylinder43). The magnet unit42is equipped with the first magnets91and the second magnets92which are each made of a polar anisotropic magnet. Each of the first magnets91and each of the second magnets92are different in polarity from each other. The first magnets91and the second magnets92are arranged alternately in the circumferential direction of the magnet unit42. Each of the first magnets91is engineered to have a portion creating an N-pole near the stator coil51. Each of the second magnets92is engineered to have a portion creating an S-pole near the stator coil51. The first magnets91and the second magnets92are each made of, for example, a permanent rare earth magnet, such as a neodymium magnet. Each of the magnets91and92is, as illustrated inFIG.9, engineered to have a direction of magnetization (which will also be referred to below as a magnetization direction) which extends in an annular shape in between a d-axis (i.e., a direct-axis) and a q-axis (i.e., a quadrature-axis) in a known d-q coordinate system where the d-axis represents the center of a magnetic pole, and the q-axis represents a magnetic boundary between the N-pole and the S-pole, in other words, where a density of magnetic flux is zero Tesla. In each of the magnets91and92, the magnetization direction is oriented in the radial direction of the annular magnet unit42close to the d-axis and also oriented in the circumferential direction of the annular magnet unit42closer to the q-axis. This layout will also be described below in detail. Each of the magnets91and92, as can be seen inFIG.9, includes a first portion250and two second portions260arranged on opposite sides of the first portion250in the circumferential direction of the magnet unit42. In other words, the first portion250is located closer to the d-axis than the second portions260are. The second portions260are arranged closer to the q-axis than the first portion250is. The direction in which the easy axis of magnetization300extends in the first portion250is oriented more parallel to the d-axis than the direction in which the easy axis of magnetization310extends in the second portions260. In other words, the magnet unit42is engineered so that an angle θ11which the easy axis of magnetization300in the first portion250makes with the d-axis is selected to be smaller than an angle θ12which the easy axis of magnetization310in the second portion260makes with the q-axis. More specifically, if a direction from the stator50(i.e., an armature) toward the magnet unit42on the d-axis is defined to be positive, the angle θ11represents an angle which the easy axis of magnetization300makes with the d-axis. Similarly, if a direction from the stator50(i.e., an armature) toward the magnet unit42on the q-axis is defined to be positive, the angle θ12represents an angle which the easy axis of magnetization310makes with the q-axis. In this embodiment, each of the angle θ11and the angle θ12is set to be 90° or less. Each of the easy axes of magnetization300and310, as referred to herein, is defined in the following way. If in each of the magnets91and92, a first one of the easy axes of magnetization is oriented in a direction A11, and a second one of the easy axes of magnetization is oriented in a direction B11, an absolute value of cosine of an angle θ which the direction A11and the direction B11make with each other (i.e., |cos θ|) is defined as the easy axis of magnetization300or the easy axis of magnetization310. The magnets91are different in easy axis of magnetization from the magnets92in regions close to the d-axis and the q-axis. Specifically, in the region close to the d-axis, the direction of the easy axis of magnetization is oriented approximately parallel to the d-axis, while in the region close to the q-axis, the direction of the easy axis of magnetization is oriented approximately perpendicular to the q-axis. Annular magnetic paths are created according to the directions of easy axes of magnetization. In each of the magnets91and92, the easy axis of magnetization in the region close to the d-axis may be oriented parallel to the d-axis, while the easy axis of magnetization in the region close to the q-axis may be oriented perpendicular to the q-axis. Each of the magnets91and92is shaped to have a first peripheral surface facing the stator50(i.e., a lower surface viewed inFIG.9which will also be referred to as a stator-side outer surface) and a second peripheral surface facing the q-axis in the circumferential direction. The first and second peripheral surfaces function as magnetic flux acting surfaces into and from which magnetic flux flows. The magnetic paths are each created to extend between the magnetic flux acting surfaces (i.e., between the stator-side outer surface and the second peripheral surface facing the q-axis). In the magnet unit42, a magnetic flux flows in an annular shape between a respective adjacent two of the N-poles and the S-poles of the magnets91and92, so that each of the magnetic paths has an increased length, as compared with, for example, radial anisotropic magnets. A distribution of the magnetic flux density will, therefore, exhibit a shape similar to a sine wave illustrated inFIG.17. This facilitates concentration of magnetic flux around the center of the magnetic pole unlike a distribution of magnetic flux density of a radial anisotropic magnet demonstrated inFIG.18as a comparative example, thereby enabling the degree of torque produced by the rotating electrical machine10to be increased. It has also been found that the magnet unit42in this embodiment has the distribution of the magnetic flux density distinct from that of a typical Halbach array magnet. InFIGS.17and18, a horizontal axis indicates the electrical angle, while a vertical axis indicates the magnetic flux density.900on the horizontal axis represents the d-axis (i.e., the center of the magnetic pole). 0° and1800on the horizontal axis represent the q-axis. Accordingly, the above-described structure of each of the magnets91and92functions to enhance the magnet magnetic flux thereof on the d-axis and reduce a change in magnetic flux near the q-axis. This enables the magnets91and92to be produced which have a smooth change in surface magnetic flux from the q-axis to the d-axis on each magnetic pole The sine wave matching percentage in the distribution of the magnetic flux density is preferably set to, for example, 40% or more. This improves the amount of magnetic flux around the center of a waveform of the distribution of the magnetic flux density as compared with a radially oriented magnet or a parallel oriented magnet in which the sine wave matching percentage is approximately 30%. By setting the sine wave matching percentage to be 60% or more, the amount of magnetic flux around the center of the waveform is improved, as compared with a concentrated magnetic flux array, such as the Halbach array. In the radial anisotropic magnet demonstrated inFIG.18, the magnetic flux density changes sharply near the q-axis. The sharper the change in magnetic flux density, the more an eddy current generated in the stator coil51will increase. The magnetic flux close to the stator coil51also sharply changes. In contrast, the distribution of the magnetic flux density in this embodiment has a waveform approximating a sine wave. A change in magnetic flux density near the q-axis is, therefore, smaller than that in the radial anisotropic magnet near the q-axis. This minimizes the generation of the eddy current. The magnet unit42creates a magnetic flux oriented perpendicular to the magnetic flux acting surface280close to the stator50near the d-axis (i.e., the center of the magnetic pole) in each of the magnets91and92. Such a magnetic flux extends in an arc-shape farther away from the d-axis as leaving the magnetic flux acting surface280close to the stator50. The more perpendicular to the magnetic flux acting surface the magnetic flux extends, the stronger the magnetic flux is. The rotating electrical machine in this embodiment is, as described above, designed to shape each of the conductor groups81to have a decreased thickness in the radial direction, so that the radial center of each of the conductor groups81is located close to the magnetic flux-acting surface of the magnet unit42, thereby causing the strong magnetic flux to be applied to the stator50from the rotor40. The stator50has the cylindrical stator core52arranged radially inside the stator coil51, that is, on the opposite side of the stator coil51to the rotor40. This causes the magnetic flux extending from the magnetic flux-acting surface of each of the magnets91and92to be attracted by the stator core52, so that it circulates through the magnetic path partially including the stator core52. This enables the orientation of the magnetic flux and the magnetic path to be optimized. Steps to assemble the bearing unit20, the housing30, the rotor40, the stator50, and the inverter unit60illustrated inFIG.5will be described below as a production method of the rotating electrical machine10. The inverter unit60is, as illustrated inFIG.6, equipped with the unit base61and the electrical components62. Operation processes including installation processes for the unit base61and the electrical components62will be explained. In the following discussion, an assembly of the stator50and the inverter unit60will be referred to as a first unit. An assembly of the bearing unit20, the housing30, and the rotor40will be referred to as a second unit. The production processes include:a first step of installing the electrical components62radially inside the unit base61;a second step of installing the unit base61radially inside the stator50to make the first unit;a third step of inserting the attaching portion44of the rotor40into the bearing unit20installed in the housing30to make the second unit;a fourth step of installing the first unit radially inside the second unit; anda fifth step of fastening the housing30and the unit base61together. The order in which the above steps are performed is the first step→the second step→the third step→the fourth step→the fifth step. In the above production method, the bearing unit20, the housing30, the rotor40, the stator50, and the inverter unit60are assembled as a plurality of sub-assemblies, and the sub-assemblies are assembled, thereby facilitating handling thereof and achieving completion of inspection of each sub-assembly. This enables an efficient assembly line to be established and thus facilitates multi-product production planning. In the first step, a high thermal conductivity material is applied or adhered to at least one of the radial inside of the unit base61and the radial outside of the electrical components62. Subsequently, the electrical components may be mounted on the unit base61. This achieves efficient transfer of heat, as generated by the semiconductor modules66, to the unit base61. In the third step, an insertion operation for the rotor40may be achieved with the housing30and the rotor40arranged coaxially with each other. Specifically, the housing30and the rotor40are assembled while sliding one of the housing30and the rotor40along a jig which positions the outer peripheral surface of the rotor40(i.e., the outer peripheral surface of the magnetic holder41) or the inner peripheral surface of the rotor40(i.e., the inner peripheral surface of the magnet unit42) with respect to, for example, the inner peripheral surface of the housing30. This achieves the assembly of heavy-weight parts without exertion of unbalanced load to the bearing unit20. This results in improvement of reliability in operation of the bearing unit20. In the fourth step, the first unit and the second unit may be installed while being placed coaxially with each other. Specifically, the first unit and the second unit are installed while sliding one of the first unit and the second unit along a jig which positions the inner peripheral surface of the unit base61with respect to, for example, the inner peripheral surfaces of the rotor40and the attaching portion44. This achieves the installation of the first and second units without any physical interference therebetween within a small clearance between the rotor40and the stator50, thereby eliminating risks of defects caused by the installation, such as physical damage to the stator coil51or damage to the permanent magnets. The above steps may alternatively be scheduled as the second step→the third step→the fourth step→the fifth step→the first step. In this order, the delicate electrical components62is finally installed, thereby minimizing stress on the electrical components in the installation processes. The structure of a control system for controlling an operation of the rotating electrical machine10will be described below.FIG.19is an electrical circuit diagram of the control system for the rotating electrical machine10.FIG.20is a functional block diagram which illustrates control steps performed by the controller110. FIG.19illustrates two sets of three-phase windings51aand51b. The three-phase windings51ainclude a U-phase winding, a V-phase winding, and a W-phase winding. The three-phase windings51binclude an X-phase winding, a Y-phase winding, and a Z-phase winding. The first inverter101and the second inverter102are provided as electrical power converters for the three-phase windings51aand51b, respectively. The inverters101and102are made of bridge circuits with as many upper and lower arms as there are the phase-windings. The current delivered to the phase windings of the stator coil51is regulated by turning on or off switches (i.e., semiconductor switches) mounted on the upper and lower arms. The dc power supply103and the smoothing capacitor104are connected parallel to the inverters101and102. The dc power supply103is made of, for example, a plurality of series-connected cells. The switches of the inverters101and102correspond to the semiconductor modules66inFIG.1. The capacitor104corresponds to the capacitor module68inFIG.1. The controller110is equipped with a microcomputer made of a CPU and memories and works to perform control energization by turning on or off the switches of the inverters101and102using several types of measured information measured in the rotating electrical machine10or requests for a motor mode or a generator mode of the rotating electrical machine10. The controller110corresponds to the control device77shown inFIG.6. The measured information about the rotating electrical machine10includes, for example, an angular position (i.e., an electrical angle) of the rotor40measured by an angular position sensor, such as a resolver, a power supply voltage (i.e., voltage inputted into the inverters) measured by a voltage sensor, and electrical current delivered to each of the phase-windings, as measured by a current sensor. The controller110produces and outputs an operation signal to operate each of the switches of the inverters101and102. A request for electrical power generation is a request for driving the rotating electrical machine10in a regenerative mode, for example, in a case where the rotating electrical machine10is used as a power source for a vehicle. The first inverter101is equipped with a series-connected part made up of an upper arm switch Sp and a lower arm switch Sn for each of the three-phase windings: the U-phase winding, the V-phase winding, and the W-phase winding. The upper arm switches Sp are connected at high-potential terminals thereof to a positive terminal of the dc power supply103. The lower arm switches Sn are connected at low-potential terminals thereof to a negative terminal (i.e., ground) of the dc power supply103. Intermediate joints of the upper arm switches Sp and the lower arm switches Sn are connected to ends of the U-phase winding, the V-phase winding, and the W-phase winding. The U-phase winding, the V-phase winding, and the W-phase winding are connected in the form of a star connection (i.e., Y-connection). The other ends of the U-phase winding, the V-phase winding, and the W-phase winding are connected with each other at a neutral point. The second inverter102is, like the first inverter101, equipped with a series-connected part made up of an upper arm switch Sp and a lower arm switch Sn for each of the three-phase windings: the X-phase winding, the Y-phase winding, and the Z-phase winding. The upper arm switches Sp are connected at high-potential terminals thereof to the positive terminal of the dc power supply103. The lower arm switches Sn are connected at low-potential terminals thereof to the negative terminal (i.e., ground) of the dc power supply103. Intermediate joints of the upper arm switches Sp and the lower arm switches Sn are connected to ends of the X-phase winding, the Y-phase winding, and the Z-phase winding. The X-phase winding, the Y-phase winding, and the Z-phase winding are connected in the form of a star connection (i.e., Y-connection). The other ends of the X-phase winding, the Y-phase winding, and the Z-phase winding are connected with each other at a neutral point. FIG.20illustrates a current feedback control operation to control electrical currents delivered to the U-phase winding, the V-phase winding, and the W-phase winding and a current feedback control operation to control electrical currents delivered to the X-phase winding, the Y-phase winding, and the Z-phase winding. The control operation for the U-phase winding, the V-phase winding, and the W-phase winding will first be discussed. InFIG.20, a current command determiner111uses a torque-dq map to determine current command values for the d-axis and the q-axis using a torque command value in the motor mode of the rotating electrical machine (which will also be referred to as a motor-mode torque command value), a torque command value in the generator mode of the rotating electrical machine10(which will be referred to as a generator-mode torque command value), and an electrical angular velocity ω derived by differentiating an electrical angle θ with respect to time. The current command determiner111is shared between the U-, V-, and W-phase windings and the X-, Y-, and W-phase windings. The generator-mode torque command value is a regenerative torque command value in a case where the rotating electrical machine10is used as a power source of a vehicle. A d-q converter112works to convert currents (i.e., three phase currents), as measured by current sensors mounted for the respective phase windings, into a d-axis current and a q-axis current that are components in a two-dimensional rotating Cartesian coordinate system in which a d-axis is defined as a direction of an axis of a magnetic field or field direction. A d-axis current feedback control device113determines a command voltage for the d-axis as a manipulated variable for bringing the d-axis current into agreement with the current command value for the d-axis in a feedback mode. A q-axis current feedback control device114determines a command voltage for the q-axis as a manipulated variable for bringing the q-axis current into agreement with the current command value for the q-axis in a feedback mode. The feedback control devices113and114calculates the command voltage as a function of a deviation of each of the d-axis current and the q-axis current from a corresponding one of the current command values using PI feedback techniques. A three-phase converter115works to convert the command values for the d-axis and the q-axis into command values for the U-phase, V-phase, and W-phase windings. Each of the devices111to115is engineered as a feedback controller to perform a feedback control operation for a fundamental current in the d-q transformation theory. The command voltages for the U-phase, V-phase, and W-phase windings are feedback control values. An operation signal generator116uses the known triangle wave carrier comparison to produce operation signals for the first inverter101as a function of the three-phase command voltages. Specifically, the operation signal generator116works to produce switch operation signals (i.e., duty signals) for the upper and lower arms for the three-phase windings (i.e., the U-, V-, and W-phase windings) under PWM control based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The same structure as described above is provided for the X-, Y-, and Z-phase windings. A d-q converter122works to convert currents (i.e., three phase currents), as measured by current sensors mounted for the respective phase windings, into a d-axis current and a q-axis current that are components in the two-dimensional rotating Cartesian coordinate system in which the d-axis is defined as the direction of the axis of the magnetic field. A d-axis current feedback control device123determines a command voltage for the d-axis. A q-axis current feedback control device124determines a command voltage for the q-axis. A three-phase converter125works to convert the command values for the d-axis and the q-axis into command values for the X-phase, Y-phase, and Z-phase windings. An operation signal generator126produces operation signals for the second inverter102as a function of the three-phase command voltages. Specifically, the operation signal generator126works to generate switch operation signals (i.e., duty signals) for the upper and lower arms for the three-phase windings (i.e., the X-, Y-, and Z-phase windings) based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. A driver117works to turn on or off the switches Sp and Sn in the inverters101and102in response to the switch operation signals produced by the operation signal generators116and126. Subsequently, a torque feedback control operation will be described below. This operation is to increase an output of the rotating electrical machine10and reduce torque loss in the rotating electrical machine10, for example, in a high-speed and high-output range wherein output voltages from the inverters101and102rise. The controller110selects one of the torque feedback control operation and the current feedback control operation and perform the selected one as a function of an operating condition of the rotating electrical machine10. FIG.21shows the torque feedback control operation for the U-, V-, and W-phase windings and the torque feedback control operation for the X-, Y-, and Z-phase windings. InFIG.21, the same reference numbers as employed inFIG.20refer to the same parts, and explanation thereof in detail will be omitted here. The control operation for the U-, V-, and W-phase windings will be described first. A voltage amplitude calculator127works to calculate a voltage amplitude command that is a command value of a degree of a voltage vector as a function of the motor-mode torque command value or the generator-mode torque command value for the rotating electrical machine and the electrical angular velocity r) derived by differentiating the electrical angle θ with respect to time. A torque calculator128aworks to estimate a torque value in the U-phase, V-phase, or the W-phase as a function of the d-axis current and the q-axis current converted by the d-q converter112. The torque calculator128amay be designed to calculate the voltage amplitude command using map information about relations among the d-axis current, the q-axis current, and the voltage amplitude command. A torque feedback controller129acalculates a voltage phase command that is a command value for a phase of the voltage vector as a manipulated variable for bringing the estimated torque value into agreement with the motor-mode torque command value or the generator-mode torque command value in the feedback mode. Specifically, the torque feedback controller129acalculates the voltage phase command as a function of a deviation of the estimated torque value from the motor-mode torque command value or the generator-mode torque command value using PI feedback techniques. An operation signal generator130aworks to produce the operation signal for the first inverter101using the voltage amplitude command, the voltage phase command, and the electrical angle θ. Specifically, the operation signal generator130acalculates the command values for the three-phase windings based on the voltage amplitude command, the voltage phase command, and the electrical angle θ and then generates switching operation signals for the upper and lower arms for the three-phase windings by means of PWM control based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The operation signal generator130amay alternatively be designed to produce the switching operation signals using pulse pattern information that is map information about relations among the voltage amplitude command, the voltage phase command, the electrical angle θ, and the switching operation signal, the voltage amplitude command, the voltage phase command, and the electrical angle θ. The same structure as described above is provided for the X-, Y-, and Z-phase windings. A torque calculator128bworks to estimate a torque value in the X-phase, Y-phase, or the Z-phase as a function of the d-axis current and the q-axis current converted by the d-q converter122. A torque feedback controller129bcalculates a voltage phase command as a manipulated variable for bringing the estimated torque value into agreement with the motor-mode torque command value or the generator-mode torque command value in the feedback mode. Specifically, the torque feedback controller129bcalculates the voltage phase command as a function of a deviation of the estimated torque value from the motor-mode torque command value or the generator-mode torque command value using PI feedback techniques. An operation signal generator130bworks to produce the operation signal for the second inverter102using the voltage amplitude command, the voltage phase command, and the electrical angle θ. Specifically, the operation signal generator130bcalculates the command values for the three-phase windings based on the voltage amplitude command, the voltage phase command, and the electrical angle θ and then generates the switching operation signals for the upper and lower arms for the three-phase windings by means of PWM control based on comparison of levels of signals derived by normalizing the three-phase command voltages using the power supply voltage with a level of a carrier signal, such as a triangle wave signal. The driver117then works to turn on or off the switches Sp and Sn for the three-phase windings in the inverters101and102in response to the switching operation signals derived by the operation signal generators130aand130b. The operation signal generator130bmay alternatively be designed to produce the switching operation signals using pulse pattern information that is map information about relations among the voltage amplitude command, the voltage phase command, the electrical angle θ, and the switching operation signal, the voltage amplitude command, the voltage phase command, and the electrical angle θ. The rotating electrical machine10has a possibility that generation of an axial current may result in electrical erosion in the bearing21or22. For example, when the stator coil51is excited or de-excited in response to the switching operation, a small switching time gap (i.e., switching unbalance) may occur, thereby resulting in distortion of magnetic flux, which may lead to the electrical erosion in the bearings21and22retaining the rotating shaft11. The distortion of magnetic flux depending upon the inductance of the stator50may create an electromotive force oriented in the axial direction, which may result in dielectric breakdown in the bearing21or22to develop the electrical erosion. In order to avoid the electrical erosion, this embodiment is engineered to take three measures as discussed below. The first erosion avoiding measure is to reduce the inductance by designing the stator50to have a core-less structure and also to shape the magnetic flux in the magnet unit42to be smooth to minimize the electrical erosion. The second erosion avoiding measure is to retain the rotating shaft in a cantilever form to minimize the electrical erosion. The third erosion avoiding measure is to unify the annular stator coil51and the stator core52using molding techniques using a molding material to minimize the electrical erosion. The first to third erosion avoiding measures will be described below in detail. In the first erosion avoiding measure, the stator50is designed to have no teeth in gaps between the conductor groups81in the circumferential direction. The sealing members57made of non-magnetic material are arranged in the gaps between the conductor groups81instead of teeth (iron cores) (seeFIG.10). This results in a decrease in inductance of the stator50, thereby minimizing the distortion of magnetic flux caused by the switching time gap occurring upon excitation of the stator coil51to reduce the electrical erosion in the bearings21and22. The inductance on the d-axis is preferably less than that on the q-axis. Additionally, each of the magnets91and92is magnetically oriented to have the easy axis of magnetization which is located near the d-axis to be more parallel to the d-axis than that located near the q-axis (seeFIG.9). This strengthens the magnetic flux on the d-axis, thereby resulting in a smooth change in surface magnetic flux (i.e., an increase or decrease in magnetic flux) from the q-axis to the d-axis on each magnetic pole of the magnets91and92. This minimizes a sudden voltage change arising from the switching imbalance to avoid electrical erosion. In the second erosion avoiding measure, the rotating electrical machine10is designed to have the bearings21and22located away from the axial center of the rotor40toward one of the ends of the rotor40opposed to each other in the axial direction thereof (seeFIG.2). This minimizes the risk of the electrical erosion as compared with a case where a plurality of bearings are arranged outside axial ends of a rotor. In other words, in the structure wherein the rotor has ends retained by the bearings, generation of a high-frequency magnetic flux results in creation of a closed circuit extending through the rotor, the stator, and the bearings (which are arranged axially outside the rotor). This leads to a possibility that the axial current may result in electrical erosion in the bearings. In contrast, the rotor40are retained by the plurality of bearings21and22in cantilever form, so that the above closed circuit does not occur, thereby minimizing the electrical erosion in the bearings21and22. In addition to the above one-side layout of the bearings21and22, the rotating electrical machine10also has the following structure. In the magnet holder41, the intermediate portion45extending in the radial direction of the rotor40is equipped with the contact avoider which axially extends to avoid physical contact with the stator50(seeFIG.2). This enables a closed circuit through which the axial current flows through the magnet holder41to be lengthened to increase the resistance thereof. This minimizes the risk of the electrical erosion of the bearings21and22. The retainer23for the bearing unit20is secured to the housing30and located on one axial end side of the rotor40, while the housing30and the unit base61(i.e., a stator holder) are joined together on the other axial end of the rotor40(seeFIG.2). These arrangements properly achieve the structure in which the bearings21and22are located only on the one end of the length of the rotating shaft11. Additionally, the unit base61is connected to the rotating shaft11through the housing30, so that the unit base61is located electrically away from the rotating shaft11. An insulating member such as resin may be disposed between the unit base61and the housing30to place the unit base61and the rotating shaft11electrically farther away from each other. This also minimizes the risk of the electrical erosion of the bearings21and22. The one-side layout of the bearings21and22in the rotating electrical machine10in this embodiment decreases the axial voltage applied to the bearings21and22and also decreases the potential difference between the rotor40and the stator50. A decrease in the potential difference applied to the bearings21and22is, thus, achieved without use of conductive grease in the bearings21and22. The conductive grease usually contains fine particles such as carbon particles, thus leading to a risk of generation of acoustic noise. In order to alleviate the above problem, this embodiment uses a non-conductive grease in the bearings21and22to minimize the acoustic noise in the bearings21and22. For instance, in a case where the rotating electrical machine10is used with an electric vehicle, it is usually required to take a measure to eliminate the acoustic noise. This embodiment is capable of properly taking such a measure. In the third erosion avoiding measure, the stator coil51and the stator core52are unified together using a molding material to minimize a positional error of the stator coil51in the stator50(seeFIG.11). The rotating electrical machine10in this embodiment is designed not to have conductor-to-conductor members (e.g., teeth) between the conductor groups81arranged in the circumferential direction of the stator coil51, thus leading to a concern about the positional error or misalignment of the stator coil51. The misalignment of the conductor of the stator coil51may be minimized by unifying the stator coil51and the stator core52in the mold. This eliminates risks of the distortion of magnetic flux arising from the misalignment of the stator coil51and the electrical erosion in the bearings21and22resulting from the distortion of the magnetic flux. The unit base61serving as a housing to firmly fix the stator core52is made of carbon fiber reinforced plastic (CFRP), thereby minimizing electrical discharge to the unit base61as compared with when the unit base61is made of aluminum, thereby avoiding the electrical erosion. An additional erosion avoiding measure may be taken to make at least one of the outer race25and the inner race26of each of the bearings21and22using a ceramic material or alternatively to install an insulating sleeve outside the outer race25. Other embodiments will be described below in terms of differences between themselves and the first embodiment. Second Embodiment In this embodiment, the polar anisotropic structure of the magnet unit42of the rotor40is changed and will be described below in detail. The magnet unit42is, as clearly illustrated inFIGS.22and23, made using a magnet array referred to as a Halbach array. Specifically, the magnet unit42is equipped with the first magnets131and the second magnets132. The first magnets131have a magnetization direction (i.e., an orientation of a magnetization vector thereof) oriented in the radial direction of the magnet unit42. The second magnets132have a magnetization direction (i.e., an orientation of the magnetization vector thereof) oriented in the circumferential direction of the magnet unit42. The first magnets131are arrayed at a given interval away from each other in the circumferential direction. Each of the second magnets132is disposed between the first magnets131arranged adjacent each other in the circumferential direction. The first magnets131and the second magnets132are each implemented by a rare-earth permanent magnet, such as a neodymium magnet. The first magnets131are arranged away from each other in the circumferential direction so as to have N-poles and S-poles which are created in radially inner portions thereof and face the stator50. The N-poles and the S-poles are arranged alternately in the circumferential direction. The second magnets132are arranged to have N-poles and S-poles alternately located adjacent the first magnets131in the circumferential direction. The cylinder43which surrounds the magnets131and132may be formed as a soft magnetic core made of a soft magnetic material and which functions as a back core. The magnet unit42in this embodiment are designed to have the easy axis of magnetization oriented in the same way as in the first embodiment relative to the d-axis and the q-axis in the d-q axis coordinate system. The magnetic members133each of which is made of a soft magnetic material are disposed radially outside the first magnets131, in other words, close to the cylinder43of the magnet holder41. Each of the magnetic members133may be made of magnetic steel sheet, soft iron, or a dust core material. Each of the magnetic members133has a length identical with that of the first magnet131(especially, a length of an outer periphery of the first magnet131) in the circumferential direction. An assembly made up of each of the first magnets131and a corresponding one of the magnetic members133has a thickness identical with that of the second magnet132in the radial direction. In other words, each of the first magnets131has the thickness smaller than that of the second magnet132by that of the magnetic member133in the radial direction. The magnets131and132and the magnetic members133are firmly secured to each other using, for example, adhesive agent. In the magnet unit42, the radial outside of the first magnets131faces away from the stator50. The magnetic members133are located on the opposite side of the first magnets131to the stator50in the radial direction (i.e., farther away from the stator50). Each of the magnetic members133has the key134in a convex shape which is formed on the outer periphery thereof and protrudes radially outside the magnetic member133, in other words, protrudes into the cylinder43of the magnet holder41. The cylinder43has the key grooves135which are formed in an inner peripheral surface thereof in a concave shape and in which the keys134of the magnetic members133are fit. The protruding shape of the keys134is contoured to conform with the recessed shape of the key grooves135. As many of the key grooves135as the keys134of the magnetic members133are formed. The engagement between the keys134and the key grooves135serves to eliminate misalignment or a positional deviation of the first magnets131, the second magnets132, and the magnet holder41in the circumferential direction (i.e. a rotational direction). The keys134and the key grooves135(i.e., convexities and concavities) may be formed either on the cylinders43of the magnet holder41or in the magnetic members133, respectively. Specifically, the magnetic members133may have the key grooves135in the outer periphery thereof, while the cylinder43of the magnet holder41may have the keys134formed on the inner periphery thereof. The magnet unit42has the first magnets131and the second magnets132alternately arranged to increase the magnetic flux density in the first magnets131. This results in concentration of magnetic flux on one surface of the magnet unit42to enhance the magnetic flux close to the stator50. The layout of the magnetic members133radially arranged outside the first magnets131, in other words, farther away from the stator50reduces partial magnetic saturation occurring radially outside the first magnets131, thereby alleviating a risk of demagnetization in the first magnets131arising from the magnetic saturation. This results in an increase in magnetic force produced by the magnet unit42. In other words, the magnet unit42in this embodiment is viewed to have portions which are usually subjected to the demagnetization and replaced with the magnetic members133. FIGS.24(a) and24(b)are illustrations which demonstrate flows of magnetic flux in the magnet unit42.FIG.24(a)illustrates a conventional structure in which the magnet unit42is not equipped with the magnetic members133.FIG.24(b)illustrates the structure in this embodiment in which the magnet unit42is equipped with the magnetic members133.FIGS.24(a) and24(b)are linearly developed views of the cylinder43of the magnet holder41and the magnet unit42. Lower sides ofFIGS.24(a) and24(b)are close to the stator50, while upper sides thereof are farther away from the stator50. In the structure shown inFIG.24(a), a magnetic flux-acting surface of each of the first magnets131and a side surface of each of the second magnets132are placed in contact with the inner peripheral surface of the cylinder43. A magnetic flux-acting surface of each of the second magnets132is placed in contact with the side surface of one of the first magnets131. Such layout causes a combined magnetic flux to be created in the cylinder43. The combined magnetic flux is made up of a magnetic flux F1which passes outside the second magnet132and then enters the surface of the first magnets131contacting the cylinder43and a magnetic flux which flows substantially parallel to the cylinder43and attracts a magnetic flux F2produced by the second magnet132. This leads to a possibility that the magnetic saturation may occur near the surface of contact between the first magnet131and the second magnet132in the cylinder43 In the structure inFIG.24(b)wherein each of the magnetic members133is disposed between the magnetic flux-acting surface of the first magnet131and the inner periphery of the cylinder43farther away from the stator50, the magnetic flux is permitted to pass through the magnetic member133. This minimizes the magnetic saturation in the cylinder43and increases resistance against the demagnetization. The structure inFIG.24(b), unlikeFIG.24(a), functions to eliminate the magnetic flux F2facilitating the magnetic saturation. This effectively enhances the permeance in the whole of the magnetic circuit, thereby ensuring the stability in properties of the magnetic circuit under elevated temperature. As compared with radial magnets used in conventional SPM rotors, the structure inFIG.24(b)has an increased length of the magnetic path passing through the magnet. This results in a rise in permeance of the magnet which enhances the magnetic force to increase the torque. Further, the magnetic flux concentrates on the center of the d-axis, thereby increasing the sine wave matching percentage. Particularly, the increase in torque may be achieved effectively by shaping the waveform of the current to a sine or trapezoidal wave under PWM control or using 120° excitation switching ICs. In a case where the stator core52is made of magnetic steel sheets, the thickness of the stator core52in the radial direction thereof is preferably half or greater than half the thickness of the magnet unit42in the radial direction. For instance, it is preferable that the thickness of the stator core52in the radial direction is greater than half the thickness of the first magnets131arranged at the pole-to-pole center in the magnet unit42. It is also preferable that the thickness of the stator core52in the radial direction is smaller than that of the magnet unit42. In this case, a magnet magnetic flux is approximately 1 T, while the saturation magnetic flux density in the stator core52is 2 T. The leakage of magnetic flux to inside the inner periphery of the stator core52is avoided by selecting the thickness of the stator core52in the radial direction to be greater than half that of the magnet unit42. Magnets arranged to have the Halbach structure or the polar anisotropic structure usually have an arc-shaped magnetic path, so that the magnetic flux may be increased in proportion to a thickness of ones of the magnets which handle a magnetic flux in the circumferential direction. In such a structure, the magnetic flux flowing through the stator core52is thought of as not exceeding the magnetic flux flowing in the circumferential direction. In other words, when the magnetic flux produced by the magnets is 1 T, while ferrous metal whose saturation magnetic flux density is 2 T is used to make the stator core52, a light weight and compact electrical rotating machine may be produced by selecting the thickness of the stator core52to be greater than half that of the magnets. The demagnetizing field is usually exerted by the stator50on the magnetic field produced by the magnets, so that the magnetic flux produced by the magnets will be 0.9 T or less. The magnetic permeability of the stator core may, therefore, be properly kept by selecting the thickness of the stator core to be half that of the magnets. Modifications of the above structure will be described below. Modification 1 In the above embodiment, the outer peripheral surface of the stator core52has a curved surface without any irregularities. The plurality of conductor groups81are arranged at given intervals away from one another on the outer peripheral surface of the stator core52. This layout may be changed. For instance, the stator core52illustrated inFIG.25is equipped with the circular ring-shaped yoke141and the protrusions142. The yoke141is located on the opposite side (i.e., a lower side, as viewed in the drawing) of the stator coil51to the rotor40in the radial direction. Each of the protrusions142protrudes into a gap between a respective two of the straight sections83arranged adjacent each other in the circumferential direction. The protrusions142are arranged at given intervals away from one another in the circumferential direction radially outside the yoke141, i.e., close to the rotor40. Each of the conductor groups81of the stator coil51engages the protrusions142in the circumferential direction, in other words, the protrusions142are used as positioners to position and array the conductor groups81in the circumferential direction. The protrusions142correspond to conductor-to-conductor members. A radial thickness of each of the protrusions142from the yoke141, in other words, a distance W, as illustrated inFIG.25, between the inner surface320of the straight sections82which is placed in contact with the yoke141and the top of the protrusion412in the radial direction of the yoke141is selected to be smaller than half a radial thickness (as indicated by H1in the drawing) of the straight sections83arranged adjacent the yoke141in the radial direction. In other words, non-conductive members (i.e., the sealing members57) preferably each occupy three-fourths of a dimension (i.e., thickness) T1(i.e., twice the thickness of the conductors82, in other words, a minimum distance between the surface320of the conductor group81placed in contact with the stator core52and the surface330of the conductor group81facing the rotor40) of the conductor groups (i.e., conductors)81in the radial direction of the stator coil51(i.e., the stator core52). Such selection of the thickness of the protrusions142causes each of the protrusions142not to function as a tooth between the conductor groups81(i.e., the straight sections83) arranged adjacent each other in the circumferential direction, so that there are no magnetic paths which would usually be formed by the teeth. The protrusions142need not necessarily be arranged between a respective circumferentially adjacent two of all the conductor groups81, but however, a single protrusion142may be disposed at least only between two of the conductor groups81which are arranged adjacent each other in the circumferential direction. For instance, the protrusions142may be disposed away from each other in the circumferential direction at equal intervals each of which corresponds to a given number of the conductor groups81. Each of the protrusions142may be designed to have any shape, such as a rectangular or arc-shape. The straight sections83may alternatively be arranged in a single layer on the outer peripheral surface of the stator core52. In a broad sense, the thickness of the protrusions142from the yoke141in the radial direction may be smaller than half that of the straight sections83in the radial direction. If an imaginary circle whose center is located at the axial center of the rotating shaft11and which passes through the radial centers of the straight sections83placed adjacent the yoke141in the radial direction is defined, each of the protrusions142may be shaped to protrude only within the imaginary circle, in other words, not to protrude radially outside the imaginary circle toward the rotor40. The above structure in which the protrusions142have the limited thickness in the radial direction and do not function as teeth in the gaps between the straight sections83arranged adjacent each other in the circumferential direction enables the adjacent straight sections83to be disposed closer to each other as compared with a case where teeth are provided in the gaps between the straight sections83. This enables a sectional area of the conductor body82ato be increased, thereby reducing heat generated upon excitation of the stator coil51. The absence of the teeth enables magnetic saturation to be eliminated to increase the amount of electrical current delivered to the stator coil51. It is, however, possible to alleviate the adverse effects arising from an increase in amount of heat generated by the increase in electrical current delivered to the stator coil51. The stator coil51, as described above, has the turns84which are shifted in the radial direction and equipped with the interference avoiding portions with the adjacent turns84, thereby enabling the turns84to be disposed away from each other in the radial direction. This enhances the heat dissipation from the turns84. The above structure is enabled to optimize the heat dissipating ability of the stator50. The radial thickness of the protrusions142may not be restricted by the dimension H1inFIG.25as long as the yoke141of the stator core52and the magnet unit42(i.e., each of the magnets91and92) of the rotor40are arranged at given distances away from one another. Specifically, the radial thickness of the protrusions142may be larger than or equal to the dimension H1inFIG.38as long as the yoke141and the magnet unit42arranged 2 mm or more away from each other. For instance, in a case where the radial thickness of the straight section83is larger than 2 mm, and each of the conductor groups81is made up of the two conductors82stacked in the radial direction, each of the protrusions142may be shaped to occupy a region ranging to half the thickness of the straight section83not contacting the yoke141, i.e., the thickness of the conductor82located farther away from the yoke141. In this case, the above beneficial advantages will be obtained by increasing the conductive sectional area of the conductor groups81as long as the radial thickness of the protrusions142is at least H1×3/2. The stator core52may be designed to have the structure illustrated inFIG.26.FIG.26omits the sealing members57, but the sealing members57may be used.FIG.26illustrates the magnet unit42and the stator core52as being arranged linearly for the sake of simplicity. In the structure ofFIG.26, the stator50has the protrusions142as conductor-to-conductor members each of which is arranged between a respective two of the conductors82(i.e., the straight sections83) located adjacent each other in the circumferential direction. The stator50is equipped with the portions350each of which magnetically operates along with one of the magnetic poles (i.e., an N-pole or an S-pole) of the magnet unit42when the stator coil51is excited. The portions350extend in the circumferential direction of the stator50. If each of the portions350has a length Wn in the circumferential direction of the stator50, the sum of widths of the protrusions142lying in a range of this length Wn (i.e., the total dimension of the protrusions412in the circumferential direction of the stator50in the range of length Wn) is defined as Wt, the saturation magnetic flux density of the protrusions412is defined as Bs, a width of a portion of the magnet unit42equivalent to one of the magnetic poles of the magnet unit42in the circumferential direction of the magnet unit42is defined as Wm, and the remanent flux density in the magnet unit42is defined as Br, the protrusions142are made of a magnetic material meeting a relation of Wt×Bs≤Wm×Br(1) The range Wn is defined to contain ones of the conductor groups81which are arranged adjacent each other in the circumferential direction and which overlap in time of excitation thereof with each other. It is advisable that a reference (i.e., a border) used in defining the range Wn be set to the center of the gap56between the conductor groups81. For instance, in the structure illustrated inFIG.26, the plurality of conductor groups81lying in the range Wn include the first, the second, the third, and the fourth conductor groups81where the first conductor group81is closest to the magnetic center of the N-pole. The range Wn is defined to include the total of those four conductor groups81. Ends (i.e., outer limits) of the range Wn are defined to lie at the centers of the gaps56. InFIG.26, the range Wn contains half of the protrusion142inside each of the ends thereof. The total of the four protrusions142lie in the range Wn. If the width of each of the protrusions142(i.e., a dimension of the protrusion142in the circumferential direction of the stator50, in other words, an interval between the adjacent conductor groups81) is defined as A, the sum of widths Wt of the protrusions142lying in the range Wn meets a relation of Wt=½A+A+A+A+½A=4A. Specifically, the three-phase windings of the stator coil51in this embodiment are made in the form of distributed windings. In the stator coil51, the number of the protrusions142for each pole of the magnet unit42, that is, the number of the gaps56each between the adjacent conductor groups81is selected to be “the number of phases×Q” where Q is the number of the conductors82for each phase which are placed in contact with the stator core52. In other words, in the case where the conductors82are stacked in the radial direction of the rotor40to constitute each of the conductor groups81, Q is the number of inner ones of the conductors82of the conductor groups81for each phase. In this case, when the three-phase windings of the stator coil51are excited in a given sequence, the protrusions142for two of the three-phases within each pole are magnetically excited. The total circumferential width Wt of the protrusions142excited upon excitation of the stator coil51within a range of each pole of the magnet unit42, therefore, meets the following relation: The number of the phases excited×Q×A=2×2×A where A is the width of each of the protrusions142(i.e., the gap56) in the circumferential direction. The total width Wt is determined in the above way. Additionally, the protrusions142of the stator core52are made of magnetic material meeting the above equation (1). The total width Wt is also viewed as being equivalent to a circumferential dimension of where the relative magnetic permeability is expected to become greater than one within each pole. The total width Wt may alternatively be determined as a circumferential width of the protrusions142in each pole with some margin. Specifically, since the number of the protrusions142for each pole of the magnet unit42is given by the number of phases×Q, the width of the protrusions412in each pole (i.e., the total width Wt) may be given by the number of phases×Q×A=3×2×A=6A. The distributed winding, as referred to herein, means that there is a pair of poles (i.e., the N-pole and the S-pole) of the stator coil51for each pair of magnetic poles. The pair of poles of the stator coil51, as referred to herein, is made of the two straight sections83in which electrical current flows in opposite directions and the turn84electrically connecting them together. Note that a short pitch winding or a full pitch winding may be viewed as an equivalent of the distributed winding as long as it meets the above conditions. Next, the case of a concentrated winding will be described below. The concentrated winding, as referred to herein, means that the width of each pair of magnetic poles is different from that of each pair of poles of the stator coil51. An example of the concentrated winding includes a structure in which there are three conductor groups81for each pair of magnetic poles, in which there are three conductor groups81for two pairs of magnetic poles, in which there are nine conductor groups81for four pairs of magnetic poles, or in which there are nine conductor groups81for five pairs of magnetic poles. In the case where the stator coil51is made in the form of the concentrated winding, when the three-phase windings of the stator coil51are excited in a given sequence, a portion of the stator coil51for two phases is excited. This causes the protrusions142for two phases to be magnetically excited. The circumferential width Wt of the protrusions142which is magnetically excited upon excitation of the stator winding in a range of each pole of the magnet unit42is given by Wt=A×2. The width Wt is determined in this way. The protrusions142are made of magnetic material meeting the above equation (1). In the above-described case of the concentrated winding, the sum of widths of the protrusions142arranged in the circumferential direction of the stator50within a region surrounded by the conductor groups81for the same phase is defined as A. The dimension Wm in the concentrated winding is given by [an entire circumference of a surface of the magnet unit42facing the air gap]×[the number of phases]÷[the number of the distributed conductor groups81]. Usually, a neodymium magnet, a samarium-cobalt magnet, or a ferrite magnet whose value of BH is higher than or equal to 20[MGOe (kJ/m{circumflex over ( )}3)] has Bd=1.0 T or more. Iron has Br=2.0 T or more. The protrusions142of the stator core52may, therefore, be made of magnetic material meeting a relation of Wt<½×Wm for realizing a high-power motor. In a case where each of the conductors82is, as described later, equipped with the outer coated layer182, the conductors82may be arranged in the circumferential direction of the stator core with the outer coated layers182placed in contact with each other. In this case, the width Wt may be viewed to be zero or equivalent to thicknesses of the outer coated layers182of the conductors82contacting with each other. The structure illustrated inFIG.25or26is designed to have conductor-to-conductor members (i.e., the protrusions142) which are too small in size for the magnet-produced magnetic flux in the rotor40. The rotor40is implemented by a surface permanent magnet rotor which has a flat surface and a low inductance, and does not have a salient pole in terms of a magnetic resistance. Such a structure enables the inductance of the stator50to be decreased, thereby reducing a risk of distortion of the magnetic flux caused by the switching time gap in the stator coil51, which minimizes the electrical erosion of the bearings21and22. Modification 2 The stator50equipped with the conductor-to-conductor members made to meet the above equation may be designed to have the following structure. InFIG.40, the stator core52is equipped with the teeth143as conductor-to-conductor members which are formed in an outer peripheral portion (an upper portion, as viewed in the drawing) of the stator core52. The teeth143protrude from the yoke141and are arranged at given intervals away from one another in the circumferential direction of the stator core52. Each of the teeth143has a thickness identical with that of the conductor group81in the radial direction. The teeth143have side surfaces placed in contact with the conductors82of the conductor groups81. The teeth143may alternatively be located away from the conductors82through gaps. The teeth143are shaped to have a restricted width in the circumferential direction. Specifically, each of the teeth143has a stator tooth which is very thin for the volume of magnets. Such a structure of the teeth143serves to achieve saturation by the magnet-produced magnetic flux at 1.8 T or more to reduce the permeance, thereby decreasing the inductance. If a surface area of a magnetic flux-acting surface of the magnet unit42facing the stator50for each pole is defined as Sm, and the remanent flux density of the magnet unit42is defined as Br, the magnetic flux in the magnet unit42will be Sm×Br. A surface area of each of the teeth143facing the rotor40is defined as St. The number of the conductors83for each phase is defined as m. When the teeth143for two phases within a range of one pole are magnetically excited upon excitation of the stator coil51, the magnetic flux in the stator50is expressed by St×m×2×Bs. The decrease in inductance may be achieved by selecting the dimensions of the teeth143to meet a relation of St×m×2×Bs<Sm×Br(2). In a case where the dimension of the magnet unit42is identical with that of the teeth143in the axial direction, the above equation (2) may be rewritten as an equation (3) of Wst×m×2×Bs<Wm×Br where Wm is the circumferential width of the magnet unit42for each pole, and Wst is the circumferential width of the teeth143. For example, when Bs=2 T, Br=1 T, and m=2, the equation (3) will be Wst<Wm/8. In this case, the decrease in inductance may be achieved by selecting the width Wst of the teeth143to be smaller than one-eighth (⅛) of the width Wm of the magnet unit42for one pole. When m is one, the width Wst of the teeth143is preferably selected to be smaller than one-fourth (¼) of the width Wm of the magnet unit42for one pole. “Wst×m×2” in the equation (3) corresponds to a circumferential width of the teeth143magnetically excited upon excitation of the stator coil51in a range of one pole of the magnet unit42. The structure inFIG.27is, like inFIGS.25and26, equipped with the conductor-to-conductor members (i.e., the teeth143) which are very small in size for the magnet-produced magnetic flux in the rotor40. Such a structure is capable of reducing the inductance of the stator50to alleviate a risk of distortion of the magnetic flux arising from the switching time gap in the stator coil51, which minimizes the probability of the electrical erosion of the bearings21and22. Note that the definitions of parameters, such as Wt, Wn, A, and Bs, associated with the stator50or parameters, such as Wm and Br, associated with the magnet unit42may refer to those in the above-described modification 1. Modification 3 The above embodiment has the sealing members57which cover the stator coil51and occupy a region including all of the conductor groups81radially outside the stator core52, in other words, lie in a region where the thickness of the sealing members57is larger than that of the conductor groups81in the radial direction. This layout of the sealing members57may be changed. For instance, the sealing members57may be, as illustrated inFIG.28, designed so that the conductors82protrude partially outside the sealing members57. Specifically, the sealing members57are arranged so that portions of the conductors82that are radially outermost portions of the conductor groups81are exposed outside the sealing members57toward the stator50. In this case, the thickness of the sealing members57in the radial direction may be identical with or smaller than that of the conductor groups81. Modification 4 The stator50may be, as illustrated inFIG.29, designed not to have the sealing members57covering the conductor groups81, i.e., the stator coil51. In this case, a gap is created between the adjacent conductor groups81arranged in the circumferential direction without a conductor-to-conductor member therebetween. In other words, no conductor-to-conductor member is disposed between the conductor groups81arranged in the circumferential direction. Air may be arranged in the gaps between the conductor groups81. The air may be viewed as a non-magnetic member or an equivalent thereof whose Bs is zero (0). Modification 5 The conductor-to-conductor members of the stator50may be made of a non-magnetic material other than resin. For instance, a non-metallic material, such as SUS304 that is austenitic stainless steel, may be used. Modification 6 The stator50may be designed not to have the stator core52. Specifically, the stator50is made of the stator coil51shown inFIG.12. The stator coil51of the stator50may be covered with a sealing member. The stator50may alternatively be designed to have an annular winding retainer made from non-magnetic material such as synthetic resin instead of the stator core52made from soft magnetic material. Modification 7 The structure in the first embodiment uses the magnets91and92arranged in the circumferential direction to constitute the magnet unit42of the rotor40. The magnet unit42may be made using an annular permanent magnet. For instance, the annular magnet95is, as illustrated inFIG.30, secured to a radially inner periphery of the cylinder43of the magnet holder41. The annular magnet95is equipped with a plurality of different magnetic poles whose polarities are arranged alternately in the circumferential direction of the annular magnet95. The magnet95lies both on the d-axis and the q-axis. The annular magnet95has a magnetic orientation directed in the radial direction on the d-axis of each magnetic pole and a magnetic orientation directed in the circumferential direction on the q-axis between the magnetic poles, thereby creating arc-shaped magnetic paths. The annular magnet95may be designed to have an easy axis of magnetization directed parallel or near parallel to the d-axis near the d-axis and also to have an easy axis of magnetization directed perpendicular or near perpendicular to the q-axis near the q-axis, thereby creating the arc-shaped magnetic paths. Modification 8 This modification is different in operation of the controller110from the above embodiment or modifications. Only differences from those in the first embodiment will be described below. The operations of the operation signal generators116and126illustrated inFIG.20and the operation signal generators130aand130billustrated inFIG.21will first be discussed below usingFIG.31. The operations executed by the operation signal generators116,126,130a, and130bare basically identical with each other. Only the operation of the operation signal generator116will, therefore, be described below for the sake of simplicity. The operation signal generator116includes the carrier generator116a, the U-phase comparator116bU, the V-phase comparator116bV, and the W-phase comparator116bW. The carrier generator116aproduces and outputs the carrier signal SigC in the form of a triangle wave signal. The U-, V-, and W-phase comparators116bU,116bV, and116bW receive the carrier signal SigC outputted by the carrier generator116aand the U-, V-, and W-phase command voltages produced by the three-phase converter115. The U-, V-, and W-phase command voltages are produced, for example, in the form of a sine wave and outputted1200out of electrical phase with each other. The U-, V-, and W-phase comparators116bU,116bV, and116bW compare the U-, V-, and W-phase command voltages with the carrier signal SigC to produce operation signals for the switches Sp and Sn of the upper and lower arms in the first inverter101for the U-, V-, and W-phase windings under PWM (Pulse Width Modulation) control. Specifically, the operation signal generator116works to produce operation signals for the switches Sp and Sn of the upper and lower arms for the U-, V-, and W-phase windings under the PWM control based on comparison of levels of signals derived by normalizing the U-, V-, and W-phase command voltages using the power supply voltage with a level of the carrier signal SigC. The driver117is responsive to the operation signals outputted by the operation signal generator116to turn on or off the switches Sp and Sn in the first inverter101for the U-, V-, and W-phase windings. The controller110controls the carrier frequency fc of the carrier signal SigC, i.e., a switching frequency for each of the switches Sp and Sn. The carrier frequency fc is altered to be higher in a low torque range or a high-speed range in the rotating electrical machine10and alternatively lower in a high torque range in the rotating electrical machine10. This altering is achieved in order to minimize a deterioration in ease of control of electrical current flowing through each of the U-, V-, and W-phase windings. In brief, the core-less structure of the stator50serves to reduce the inductance in the stator50. The reduction in inductance usually results in a decrease in electrical time constant in the rotating electrical machine10. This leads to a possibility that a ripple of current flowing through each of the phase windings may be increased, thereby resulting in the deterioration in ease of control of the current flowing through the phase winding, which causes control divergence. The adverse effects of the above deterioration on the ease of control usually become higher when the current (e.g., an effective value of the current) flowing through the winding lies in a low current region than when the current lies in a high current range. In order to alleviate such a problem, the controller110in this embodiment is designed to alter the carrier frequency fc. How to alter the carrier frequency fc will be described below with reference toFIG.32. This operation of the operation signal generator116is executed by the controller110cyclically at a given interval. First, in step S10, it is determined whether electrical current flowing through each of the three-phase windings51alies in the low current range. This determination is made to determine whether torque now produced by the rotating electrical machine10lies in the low torque range. Such a determination may be achieved according to the first method or the second method, as discussed below. First Method The estimated torque value of the rotating electrical machine10is calculated using the d-axis current and the q-axis current converted by the d-q converter112. If the estimated torque value is determined to be lower than a torque threshold value, it is concluded that the current flowing through the winding51alies in the low current range. Alternatively, if the estimated torque value is determined to be higher than or equal to the torque threshold value, it is concluded that the current lies in the high current range. The torque threshold value is selected to be half, for example, the degree of starting torque (also called locked rotor torque) in the rotating electrical machine10. Second Method If an angle of rotation of the rotor40measured by an angle sensor is determined to be higher than or equal to a speed threshold value, it is determined that the current flowing through the winding51alies in the low current range, that is, in the high-speed range. The speed threshold value may be selected to be a rotational speed of the rotating electrical machine10when a maximum torque produced by the rotating electrical machine10is equal to the torque threshold value. If a NO answer is obtained in step S10, meaning that the current lies in the high current range, then the routine proceeds to step S11wherein the carrier frequency fc is set to the first frequency fL. Alternatively, if a YES answer is obtained in step S10, then the routine proceeds to step S12wherein the carrier frequency fc is set to the second frequency fH that is higher than the first frequency fL. As apparent from the above discussion, the carrier frequency fc when the current flowing through each of the three-phase windings lies in the low current range is selected to be higher than that when the current lies in the high current range. The switching frequency for the switches Sp and Sn is, therefore, increased in the low current range, thereby minimizing a rise in current ripple to ensure the stability in controlling the current. When the current flowing through each of the three-phase windings lies in the high current range, the carrier frequency fc is selected to be lower than that when the current lies in the low current range. The current flowing through the winding in the high current range usually has an amplitude larger than that when the current lies in the low current range, so that the rise in current ripple arising from the reduction in inductance has a low impact on the ease of control of the current. It is, therefore, possible to set the carrier frequency fc in the high current range to be lower than that in the low current range, thereby reducing a switching loss in the inverters101and102. This modification is capable of realizing the following modes. If a YES answer is obtained in step S10inFIG.32when the carrier frequency fc is set to the first frequency fL, the carrier frequency fc may be changed gradually from the first frequency fL to the second frequency fH. Alternatively, if a NO answer is obtained in step S10when the carrier frequency fc is set to the second frequency fH, the carrier frequency fc may be changed gradually from the second frequency fH to the first frequency fL. The operation signals for the switches may alternatively be produced using SVM (Space Vector Modulation) instead of PWM. The above altering of the switching frequency may also be made. Modification 9 In each of the embodiments, two pairs of conductors making up the conductor groups81for each phase are, as illustrated inFIG.33(a), arranged parallel to each other.FIG.33(a)is a view which illustrates an electrical connection of the first and second conductors88aand88bthat are the two pairs of conductors. The first and second conductors88aand88bmay alternatively be, as illustrated inFIG.33(b), connected in series with each other instead of the connection inFIG.33(a). Three or more pairs of conductors may be stacked in the form of multiple layers.FIG.34illustrates four pairs of conductors: the first to fourth conductors88ato88dwhich are stacked. The first conductor88a, the second conductor88b, the third conductor88c, and the fourth conductor88dare arranged in this order from the stator core52in the radial direction. The third and fourth conductors88cand88dare, as illustrated inFIG.33(c), connected in parallel to each other. The first conductor88ais connected to one of joints of the third and fourth conductors88cand88d. The second conductor88bis connected to the other joint of the third and fourth conductors88cand88d. The parallel connection of conductors usually results in a decrease in current density of those conductors, thereby minimizing thermal energy produced upon energization of the conductors. Accordingly, in the structure in which a cylindrical stator winding is installed in a housing (i.e., the unit base61) with the coolant path74formed therein, the first and second conductors88aand88bwhich are connected in non-parallel to each other are arranged close to the stator core52placed in contact with the unit base61, while the third and fourth conductors88cand88dwhich are connected in parallel to each other are disposed farther away from the stator core52. This layout equalizes the cooling ability of the conductors88ato88dstacked in the form of multiple layers. The conductor group81including the first to fourth conductors88ato88dmay have a thickness in the radial direction which is smaller than a circumferential width of the conductor groups81for one phase within a region of one pole. Modification 10 The rotating electrical machine10may alternatively be designed to have an inner rotor structure (i.e., an inward rotating structure). In this case, the stator50may be mounted, for example, on a radial outside within the housing30, while the rotor40may be disposed on a radial inside within the housing30. The inverter unit60may be mounted one or both axial sides of the stator50or the rotor40.FIG.35is a transverse sectional view of the rotor40and the stator50.FIG.36is an enlarged view which partially illustrates the rotor40and the stator50inFIG.35. The inner rotor structure inFIGS.35and36is substantially identical with the outer rotor structure inFIGS.8and9except for the layout of the rotor40and the stator50in the radial direction. In brief, the stator50is equipped with the stator coil51having the flattened conductor structure and the stator core52with no teeth. The stator coil51is installed radially inside the stator core52. The stator core52, like the outer rotor structure, has any of the following structures.(A) The stator50has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. As the conductor-to-conductor members, magnetic material is used which meets a relation of Wt×Bs≤Wm×Br where Wt is a width of the conductor-to-conductor members in the circumferential direction within one magnetic pole, Bs is the saturation magnetic flux density of the conductor-to-conductor members, Wm is a width of the magnet unit equivalent to one magnetic pole in the circumferential direction, and Br is the remanent flux density in the magnetic unit.(B) The stator50has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. The conductor-to-conductor members are each made of a non-magnetic material.(C) The stator50has no conductor-to-conductor member disposed between the conductor portions in the circumferential direction. The same is true of the magnets91and92of the magnet unit42. Specifically, the magnet unit42is made up of the magnets91and92each of which is magnetically oriented to have the easy axis of magnetization which is located near the d-axis to be more parallel to the d-axis than that near the q-axis which is defined on the boundary of the magnetic poles. The details of the magnetization direction in each of the magnets91and92are the same as described above. The magnet unit42may be the annular magnet95(seeFIG.30). FIG.37is a longitudinal sectional view of the rotating electrical machine10designed to have the inner rotor structure.FIG.37corresponds toFIG.2. Differences from the structure inFIG.2will be described below in brief. InFIG.37, the annular stator50is retained inside the housing30. The rotor40is rotatably disposed inside the stator50with an air gap therebetween. The bearings21and22are, like inFIG.2, offset from the axial center of the rotor40in the axial direction of the rotor40, so that the rotor40is retained in the cantilever form. The inverter60is mounted inside the magnet holder41of the rotor40. FIG.38illustrates the inner rotor structure of the rotating electrical machine10which is different from that described above. The housing30has the rotating shaft11retained by the bearings21and22to be rotatable. The rotor40is secured to the rotating shaft11. Like the structure inFIG.2, each of the bearings21and22is offset from the axial center of the rotor40in the axial direction of the rotor40. The rotor40is equipped with the magnet holder41and the magnet unit42. The rotating electrical machine10inFIG.38is different from that inFIG.37in that the inverter unit60is not located radially inside the rotor40. The magnet holder41is joined to the rotating shaft11radially inside the magnet unit42. The stator50is equipped with the stator coil51and the stator core52and secured to the housing30. Note that the definitions of parameters, such as Wt, Wn, Wm, and Bs, associated with the stator50or parameters, such as θ11, θ12, X1, X2, Wm, and Br, associated with the magnet unit42may refer to those in the above-described first embodiment or the modification 1. Modification 11 The inner rotor structure of a rotating electrical machine which is different from that described above will be discussed below.FIG.39is an exploded view of the rotating electrical machine200.FIG.40is a sectional side view of the rotating electrical machine200. In the following discussion, a vertical direction matches a vertical direction of the rotating electrical machine200illustrated in each ofFIGS.39and40. The rotating electrical machine200, as illustrated inFIGS.39and40, includes the stator203and the rotor204. The stator203is equipped with the annular stator core201and the multi-phase stator winding202. The rotor204is disposed inside the stator core201to be rotatable. The stator203works as an armature. The rotor204works as a field magnet. The stator core201is made of a stack of silicone steel plates. The stator winding202is installed in the stator core201. Although not illustrated, the rotor204is equipped with a rotor core and a plurality of permanent magnet arranged in the form of a magnet unit. The rotor core has formed therein a plurality of holes which are arranged at equal intervals away from each other in the circumferential direction of the rotor core. The permanent magnets which are magnetized to have magnetization directions changed alternately in adjacent magnetic poles are disposed in the holes of the rotor core. The permanent magnets of the magnet unit may be designed, like inFIG.23, to have a Halbach array structure or a similar structure. The permanent magnets of the magnet unit may alternatively be made of anisotropic magnets, as described with reference toFIG.9or30, in which the magnetic orientation (i.e., the magnetization direction) extends in an arc-shape between the d-axis which is defined on the magnetic center and the q-axis which is defined on the boundary of the magnetic poles. The stator203may be made to have one of the following structures.(A) The stator203has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. As the conductor-to-conductor members, magnetic material is used which meets a relation of Wt×Bs≤Wm×Br where Wt is a width of the conductor-to-conductor members in the circumferential direction within one magnetic pole, Bs is the saturation magnetic flux density of the conductor-to-conductor members, Wm is a width of the magnet unit equivalent to one magnetic pole in the circumferential direction, and Br is the remanent flux density in the magnetic unit.(B) The stator203has the conductor-to-conductor members each of which is disposed between the conductor portions in the circumferential direction. The conductor-to-conductor members are each made of a non-magnetic material.(C) The stator203has no conductor-to-conductor member disposed between the conductor portions in the circumferential direction. The rotor204has the magnet unit which is made up of a plurality of magnets each of which is magnetically oriented to have the easy axis of magnetization which is located near the d-axis to be more parallel to the d-axis than that near the q-axis which is defined on the boundary of the magnetic poles. The annular inverter case211is disposed on one end side of an axis of the rotating electrical machine200. The inverter case211has a lower surface placed in contact with an upper surface of the stator core201. The inverter case211has disposed therein a plurality of power modules212constituting an inverter circuit, the smoothing capacitors213working to reduce a variation in voltage or current (i.e., a ripple) resulting from switching operations of semiconductor switches, the control board214equipped with a controller, the current sensor215working to measure a phase current, and the resolver stator216serving as a rotational speed sensor for the rotor204. The power modules212are equipped with IGBTs serving as semiconductor switches and diodes. The inverter case211has the power connector217which is disposed on a circumferential edge thereof for connection with a dc circuit for a battery mounted in a vehicle. The inverter case211also has the signal connector218which is disposed on the circumferential edge thereof for achieving transmission of signals between the rotating electrical machine200and a controller installed in the vehicle. The inverter case211is covered with the top cover219. The dc power produced by the battery installed in the vehicle is inputted into the power connector217, converted by the switches of the power modules212to an alternating current, and then delivered to phase windings of the stator winding202. The bearing unit221and the annular rear case222are disposed on the opposite end side of the axis of the stator core to the inverter case211. The bearing unit221retains a rotation axis of the rotor204to be rotatable. The rear case222has the bearing unit221disposed therein. The bearing unit221is equipped with, for example, two bearings and offset from the center of the length of the rotor204toward one of the ends of the length of the rotor204. The bearing unit221may alternatively be engineered to have a plurality of bearings disposed on both end sides of the stator core201opposed to each other in the axial direction, so that the bearings retain both the ends of the rotation shaft. The rear case222is fastened to a gear case or a transmission of the vehicle using bolts, thereby securing the rotating electrical machine200to the vehicle. The inverter case211has formed therein the cooling flow path211athrough which cooling medium flows. The cooling flow path211ais defined by closing an annular recess formed in a lower surface of the inverter case211by an upper surface of the stator core201. The cooling flow path211asurrounds a coil end of the stator winding202. The cooling flow path211ahas the module cases212aof the power modules212disposed therein. Similarly, the rear case222has formed therein the cooling flow path222awhich surrounds a coil end of the stator winding202. The cooling flow path222ais defined by closing an annular recess formed in an upper surface of the rear case222by a lower surface of the stator core201. Note that the definitions of parameters, such as Wt, Wn, Wm, and Bs, associated with the stator50or parameters, such as θ11, θ12, X1, X2, Wm, and Br, associated with the magnet unit42may refer to those in the above-described first embodiment or the modification 1. Modification 12 The above discussion has referred to the revolving-field type of rotating electrical machines, but a revolving armature type of rotating electrical machine may be embodied.FIG.41illustrates the revolving armature type of rotating electrical machine230. The rotating electrical machine230inFIG.41has the bearing232retained by the housings231aand231b. The bearing232retains the rotating shaft233to be rotatable. The bearing232is made of, for example, an oil-impregnated bearing in which a porous metal is impregnated with oil. The rotating shaft233has secured thereto the rotor234which works as an armature. The rotor234includes the rotor core235and the multi-phase rotor winding236secured to an outer periphery of the rotor core235. The rotor core235of the rotor234is designed to have the slot-less structure. The multi-phase rotor winding236has the flattened conductor structure as described above. In other words, the multi-phase rotor winding236is shaped to have an area for each phase which has a dimension in the circumferential direction which is larger than that in the radial direction. The stator237is disposed radially outside the rotor234. The stator237works as a field magnet. The stator237includes the stator core238and the magnet unit239. The stator core238is secured to the housing231a. The magnet unit239is attached to an inner periphery of the stator core238. The magnet unit239is made up of a plurality of magnets arranged to have magnetic poles alternately arrayed in the circumferential direction. Like the magnet unit42described above, the magnet unit239is magnetically oriented to have the easy axis of magnetization which is located near the d-axis to be more parallel to the d-axis than that near the q-axis that is defined on a boundary between the magnetic poles. The magnet unit239is equipped with magnetically oriented sintered neodymium magnets whose intrinsic coercive force is 400 [kA/m] or more and whose remanent flux density is 1.0 [T] or more. The rotating electrical machine230in this embodiment is engineered as a two-pole three-coil brush coreless motor. The multi-phase rotor winding236is made of three coils. The magnet unit239is designed to have two poles. A ratio of the number of poles and the number of coils in typical brush motors is 2:3, 4:10, or 4:21 depending upon intended use. The rotating shaft233has the commutator241secured thereto. A plurality of brushes242are arranged radially outside the commutator241. The commutator241is electrically connected to the multi-phase rotor winding236through the conductors234embedded in the rotating shaft233. The commutator241, the brushes242, and the conductors243are used to deliver dc current to the multi-phase rotor winding236. The commutator241is made up of a plurality of sections arrayed in a circumferential direction thereof depending upon the number of phases of the multi-phase rotor winding236. The brushes242may be connected to a dc power supply, such as a storage battery, using electrical wires or using a terminal block. The rotating shaft233has the resinous washer244disposed between the bearing232and the commutator241. The resinous washer244serves as a sealing member to minimize leakage of oil seeping out of the bearing232, implemented by an oil-impregnated bearing, to the commutator241. Modification 13 Each of the conductors82of the stator coil51of the rotating electrical machine10may be designed to have a stack of a plurality of insulating coatings or layers laid on each other. For instance, each of the conductors82may be made by covering a bundle of a plurality of insulating layer-coated conductors (i.e., wires) with an insulating layer, so that the insulating layer (i.e., an inner insulating layer) of each of the conductors82is covered with the insulating layer (i.e., an outer insulating layer) of the bundle. The outer insulating layer is preferably designed to have an insulating ability greater than that of the inner insulating layer. Specifically, the thickness of the outer insulating layer is selected to be larger than that of the inner insulating layer. For instance, the outer insulating layer has a thickness of 100 μm, while the inner insulating layer has a thickness of 40 μm. Alternatively, the outer insulating layer may have a permittivity lower than that of the inner insulating layer. Each of the conductors82may have any of the above structures. Each wire is preferably made of a collection of conductive members or fibers. As apparent from the above discussion, the rotating electrical machine10becomes useful in a high-voltage system of a vehicle by increasing the insulation ability of the outermost layer of the conductor82. The above structure enables the rotating electrical machine10to be driven in low pressure conditions such as highlands. Modification 14 Each of the conductors82equipped with a stack of a plurality of insulating layers may be designed to have at least one of a linear expansion coefficient and the degree of adhesion strength different between an outer one and an inner one of the insulating layers. The conductors82in this modification are illustrated inFIG.42. InFIG.42, the conductor82includes a plurality of (four in the drawing) wires181, the outer coated layer182(i.e., an outer insulating layer) with which the wires181are covered and which is made of, for example, resin, and the intermediate layer183(i.e., an intermediate insulating layer) which is disposed around each of the wires181within the outer coated layer182. Each of the wires181includes the conductive portion181amade of copper material and the conductor-coating layer (i.e., an inner insulating layer) made of electrical insulating material. The outer coated layer182serves to electrically insulate between phase-windings of the stator winding. Each of the wires181is preferably made of a collection of conductive members or fibers. The intermediate layer183has a linear expansion coefficient higher than that of the coated layer181b, but lower than that of the outer coated layer182. In other words, the linear expansion coefficient of the conductor82is increased from an inner side to an outer side thereof. Typically, the outer coated layer182is designed to have a linear expansion coefficient higher than that of the coated layer181b. The intermediate layer183, as described above, has a linear expansion coefficient intermediate between those of the coated layer181band the outer coated layer182and thus serves as a cushion to eliminate a possibility that the inner and outer layers may be simultaneously broken. Each of the wires181of the conductor82has the conductive portion181aand the coated layer181badhered to the conductive portion181a. The coated layer181band the intermediate layer183are also adhered together. The intermediate layer183and the outer coated layer182are adhered together. Such joints have a strength of adhesion decreasing toward an outer side of the conductor82. In other words, the strength of adhesion between the conductive portion181aand the coated layer181bis lower than that between the coated layer181band the intermediate layer183and between the intermediate layer183and the outer coated layers182. The strength of adhesion between the coated layer181band the intermediate layer183may be higher than or identical with that between the intermediate layer183and the outer coated layers182. Usually, the strength of adhesion between, for example, two coated layers may be measured as a function of a tensile strength required to peel the coated layers away from each other. The strength of adhesion of the conductor82is selected in the above way to minimize the possibility that the inner and outer layers may be broken together arising from a temperature difference between inside and outside the conductor82when heated or cooled. Usually, the heat generation or temperature change in the rotating electrical machine results in copper losses arising from heat from the conductive portion181aof the wire181and from an iron core. These two types of loss result from the heat transmitted from the conductive portion181ain the conductor82or from outside the conductor82. The intermediate layer183does not have a heat source. The intermediate layer183has the strength of adhesion serving as a cushion for the coated layer181band the outer coated layer182, thereby eliminating the possibility that the coated layer181band the outer coated layer182may be simultaneously broken. This enables the rotating electrical machine to be used in conditions, such as in vehicles, wherein a resistance to high pressure is required, or the temperature greatly changes. In addition, the wire181may be made of enamel wire with a layer (i.e., the coated layer181b) coated with resin, such as PA, PI or PAI. Similarly, the outer coated layer182outside the wire181is preferably made of PA, PI, and PAI and has a large thickness. This minimizes a risk of breakage of the outer coated layer182caused by a difference in linear expansion coefficient. Instead of use of PA, PI, PAI to make the outer coated layer182having a large thickness, material, such as PPS, PEEK, fluorine resin, polycarbonate, silicone, epoxy, polyethylene naphthalate, or LCP which has a dielectric permittivity lower than that of PI or PAI is preferably used to increase the conductor density of the rotating electrical machine. The use of such resin enhances the insulating ability of the outer coated layer182even when it has a thickness smaller than or equal to that of the coated layer181band increases the occupancy of the conductive portion. Usually, the above resin has the degree of electric permittivity higher than that of an insulating layer of enamel wire. Of course, there is an example where the state of formation or additive results in a decrease in electric permittivity thereof. Usually, PPS and PEEK is higher in linear expansion coefficient than an enamel-coated layer, but lower than other types of resin and thus is useful only for the outer of the two layers. The strength of adhesion of the two types of coated layers arranged outside the wire181(i.e., the intermediate insulating layer and the outer insulating layer) to the enamel coated layer of the wire181is preferably lower than that between the copper wire and the enamel coated layer of the wire181, thereby minimizing a possibility that the enamel coated layer and the above two types of coated layers are simultaneously broken. In a case where the stator is equipped with a water-cooling mechanism, a liquid cooling mechanism, or an air-cooling mechanism, thermal stress or impact stress is thought of as being exerted first on the outer coated layers182. The thermal stress or the impact stress is decreased by partially bonding the insulating layer of the wire181and the above two types of coated layers together even if the insulation layer is made of resin different from those of the above two types of coated layers. In other words, the above-described insulating structure may be created by placing a wire (i.e., an enamel wire) and an air gap and also arranging fluorine resin, polycarbonate, silicone, epoxy, polyethylene naphthalate, or LCP. In this case, adhesive which is made from epoxy, low in electric permittivity, and also low in linear expansion coefficient is preferably used to bond the outer coated layer and the inner coated layer together. This eliminates breakage of the coated layers caused by friction arising from vibration of the conductive portion or breakage of the outer coated layer due to the difference in linear expansion coefficient as well as the mechanical strength. The outermost layer which serves to ensure the mechanical strength or securement of the conductor82having the above structure is preferably made from resin material, such as epoxy, PPS, PEEK, or LCP which is easy to shape and similar in dielectric constant or linear expansion coefficient to the enamel coated layer, typically in a final process for a stator winding. Typically, the resin potting is made using urethane or silicone. Such resin, however, has a linear expansion coefficient approximately twice that of other types of resin, thus leading to a possibility that thermal stress is generated when the resin potting is used, so that it is sheared. The above resin is, therefore, unsuitable for use where requirements for insulation are severe and 60V or more. The final insulation process to make the outermost layer using injection molding techniques with epoxy, PPS, PEEK, or LCP satisfies the above requirements. Other modifications will be listed below. The distance DM between a surface of the magnet unit42which faces the armature and the axial center of the rotor in the radial direction may be selected to be 50 mm or more. For instance, the distance DM, as illustrated inFIG.4, between the radial inner surface of the magnet unit42(i.e., the first and second magnets91and92) and the center of the axis of the rotor40may be selected to be 50 mm or more. The small-sized slot-less structure of the rotating electrical machine whose output is several tens or hundreds watt is known which is used for models. The disclosers or inventors of this application have not seen examples where the slot-less structure is used with large-sized industrial rotating electrical machines whose output is more than 10 kW. The disclosures or inventors of this application have studied the reason for this. Modern major rotating electrical machines are categorized into four main types: a brush motor, a squirrel-cage induction motor, a permanent magnet synchronous motor, and a reluctance motor. Brush motors are supplied with exciting current using brushes. Large-sized brush motors, therefore, have an increased size of brushes, thereby resulting in complex maintenance thereof. With the remarkable development of semiconductor technology, brushless motors, such as induction motors, have been used instead. In the field of small-sized motors, a large number of coreless motors have also come on the market in terms of low inertia or economic efficiency. Squirrel-cage induction motors operate on the principle that a magnetic field produced by a primary stator winding is received by a secondary stator core to deliver induced current to bracket-type conductors, thereby creating a magnetic reaction field to generate torque. In terms of small-size and high-efficiency of the motors, it is inadvisable that the stator and the rotor be designed not to have iron cores. Reluctance motors are motors designed to use a change in reluctance in an iron core. It is, thus, inadvisable that the iron core be omitted in principle. In recent years, permanent magnet synchronous motors have used an IPM (Interior Permanent Magnet) rotor. Especially, most large-sized motors use an IPM rotor unless there are special circumstances. IPM motors has properties of producing both magnet torque and reluctance torque. The ratio between the magnet torque and the reluctance torque is timely controlled using an inverter. For these reasons, the IMP motors are thought of as being compact and excellent in ability to be controlled. According to analysis by the disclosures or inventors of this application, torque on the surface of a rotor producing the magnet torque and the reluctance torque is expressed inFIG.43as a function of the distance DM between the surface of the magnet unit which faces the armature and the center of the axis of the rotor, that is, the radius of a stator core of a typical inner rotor indicated on the horizontal axis. The potential of the magnet torque, as can be seen in the following equation (eq1), depends upon the strength of magnetic field created by a permanent magnet, while the potential of the reluctance torque, as can be seen in the following equation (eq2), depends upon the degree of inductance, especially, on the q-axis. The magnet torque=k·Ψ·Iq(eq1) The reluctance torque=k·(Lq−Ld)·Iq·Id(eq2) Comparison between the strength of magnetic field produced by the permanent magnet and the degree of inductance of a winding using the distance DM shows that the strength of magnetic field created by the permanent magnet, that is, the amount of magnetic flux Ψ is proportional to a total area of a surface of the permanent magnet which faces the stator. In case of a cylindrical stator, such a total area is a cylindrical surface area of the permanent magnet. Technically speaking, the permanent magnet has an N-pole and an S-pole, and the amount of magnetic flux Ψ is proportional to half the cylindrical surface area. The cylindrical surface area is proportional to the radius of the cylindrical surface and the length of the cylindrical surface. When the length of the cylindrical surface is constant, the cylindrical surface area is proportional to the radius of the cylindrical surface. The inductance Lq of the winding depends upon the shape of the iron core, but its sensitivity is low and proportional to the square of the number of turns of the stator winding, so that it is strongly dependent upon the number of the turns. The inductance L is expressed by the following relation L=μ·N{circumflex over ( )}2×S/δ where μ is permeability of a magnetic circuit, N is the number of turns, S is a sectional area of the magnetic circuit, and δ is an effective length of the magnetic circuit. The number of turns of the winding depends upon the size of space occupied by the winding. In the case of a cylindrical motor, the number of turns, therefore, depends upon the size of space occupied by the winding of the stator, in other words, areas of slots in the stator. The slot is, as demonstrated inFIG.44, rectangular, so that the area of the slot is proportional to the product of a and b where a is the width of the slot in the circumferential direction, and b is the length of the slot in the radial direction. The width of the slot in the circumferential direction becomes large with an increase in diameter of the cylinder, so that the width is proportional to the diameter of the cylinder. The length of the slot in the radial direction is proportional to the diameter of the cylinder. The area of the slot is, therefore, proportional to the square of the diameter of the cylinder. It is apparent from the above equation (eq2) that the reluctance torque is proportional to the square of current in the stator. The performance of the rotating electrical machine, therefore, depends upon how much current is enabled to flow in the rotating electrical machine, that is, depends upon the areas of the slots in the stator. The reluctance is, therefore, proportional to the square of the diameter of the cylinder for a cylinder of constant length. Based on this fact, a relation of the magnetic torque and the reluctance torque with the distance DM is shown by plots inFIG.43. The magnet torque is, as shown inFIG.43, increased linearly as a function of the distance DM, while the reluctance torque is increased in the form of a quadratic function as a function of the distance DM.FIG.43shows that when the distance DM is small, the magnetic torque is dominant, while the reluctance torque becomes dominant with an increase in diameter of the stator core. The disclosers or inventors of this application have arrived at the conclusion that an intersection of lines expressing the magnetic torque and the reluctance torque inFIG.43lies near 50 mm that is the radius of the stator core. It seems that it is difficult for a motor whose output is 10 kW and whose stator core has a radius much larger than 50 mm to omit the stator core because the use of the reluctance torque is now mainstream. This is one of reasons why the slot-less structure is not used in large-sized motors. The rotating electrical machine using an iron core in the stator always faces a problem associated with magnetic saturation of the iron core. In particular, radial gap type rotating electrical machines have a longitudinal section of the rotating shaft which is of a fan shape for each magnetic pole, so that the further inside the rotating electrical machine, the smaller the width of a magnetic circuit, resulting in inner dimensions of teeth forming slots in the core becoming a factor of the limit of performance of the rotating electrical machine. Even if a high-performance permanent magnet is used, generation of magnetic saturation in the permanent magnet will lead to a difficulty in producing a required degree of performance of the permanent magnet. It is necessary to design the permanent magnet to have an increased inner diameter in order to eliminate a risk of occurrence of the magnetic saturation, which results in an increase size of the rotating electrical machine. For instance, a typical rotating electrical machine with a distributed three-phase winding is designed so that three to six teeth serve to produce a flow of magnetic flux for each magnetic pole, but encounters a risk that the magnetic flux may concentrate on a leading one of the teeth in the circumferential direction, thereby causing the magnetic flux not to flow uniformly in the three to six teeth. For instance, the flow of magnetic flux concentrates on one or two of the teeth, so that the one or two of the teeth in which the magnetic saturation is occurring will move in the circumferential direction with rotation of the rotor, which may lead to a factor causing the slot ripple. For the above reasons, it is required to omit the teeth in the slot-less structure of the rotating electrical machine whose distance DM is 50 mm or more to eliminate the risk of generation of the magnetic saturation. The omission of the teeth, however, results in an increase in magnetic resistance in magnetic circuits of the rotor and the stator, thereby decreasing torque produced by the rotating electrical machine. The reason for such an increase in magnetic resistance is that there is, for example, a large air gap between the rotor and the stator. The slot-less structure of the rotating electrical machine whose distance DM is 50 mm or more, therefore, has room for improvement for increasing the output torque. There are numerous beneficial advantages to use the above torque-increasing structure in the slot-less structure of rotating electrical machines whose distance DM is 50 mm or more. Not only the outer rotor type rotating electrical machines, but also the inner rotor type rotating electrical machines are preferably designed to have the distance DM of 50 mm or more between the surface of the magnet unit which faces the armature and the center of the axis of the rotor in the radial direction. The stator winding51of the rotating electrical machine10may be designed to have only the single straight section83of the conductor82arranged in the radial direction. Alternatively, a plurality of straight sections83, for example, three, four, five, or six straight sections83may be stacked on each other in the radial direction. For example, the structure illustrated inFIG.2has the rotating shaft11extending outside the ends of length of the rotating electrical machine10. However, the structure may alternatively be designed to have the rotating shaft11protruding outside only one of the ends of the rotating electrical machine10. In this case, it is advisable that a portion of the rotating shaft11which is retained by the bearing unit20in the cantilever form be located on one of the ends of the rotating electrical machine, and that the rotating shaft11protrude outside such an end of the rotating electrical machine. This structure has the rotating shaft11not protruding inside the inverter unit60, thus enabling a wide inner space of the inverter unit60, i.e., the cylinder71to be used. The above structure of the rotating electrical machine10uses non-conductive grease in the bearings21and22but, however, may alternatively be designed to have conductive grease in the bearings21and22. For instance, conductive grease containing metallic particles or carbon particles may be used. Bearings may be respectively mounted on both axial ends of the rotor40for retaining the rotating shaft11to be rotatable. For example, the structure ofFIG.1may have bearings mounted on opposite sides of the inverter unit60in the axial direction. The magnet holder41of the rotor40of the rotating electrical machine10has the intermediate portion45equipped with the inner shoulder49aand the annular outer shoulder49b. The magnet holder41however may alternatively be designed to have the flat intermediate portion45without the shoulders49aand49b. The conductor body82aof each of the conductors82of the stator winding51of the rotating electrical machine10is made of a collection of the wires86, however, may alternatively be formed using a square conductor having a rectangular cross section. The conductor82may alternatively be made using a circular conductor having a circular cross section or an oval cross section. The rotating electrical machine10has the inverter unit60arranged radially inside the stator50, but however, may alternatively be designed not to have the inverter60disposed inside the stator50. This enables the stator50to have a radial inner void space in which parts other than the inverter unit60may be mounted. The rotating electrical machine10may be designed not to have the housing30. In this case, the rotor40or the stator50may be retained by a wheel or another part of a vehicle. Embodiments for In-Wheel Motor for Vehicles Embodiments in which a rotating electrical machine is incorporated into a hub of a wheel of a vehicle, such as, an automotive vehicle in the form of an in-wheel motor will be described below. FIG.45is a perspective view which illustrates the tire wheel assembly400engineered to have an in-wheel motor structure and a surrounding structure.FIG.46is a longitudinal sectional view which illustrates the tire wheel assembly400and the surrounding structure.FIG.47is a perspective exploded view of the tire wheel assembly400. These views are perspective illustrations of the tire wheel assembly400, as viewed from inside the vehicle. The vehicle may use the in-wheel motor structure in different modes. For instance, in a case where the vehicle is equipped with four wheels: two front wheel and two rear wheels, either or both of the front wheels and the rear wheel may be engineered to have the in-wheel motor structure in this embodiment. Alternatively, the in-wheel motor structure may also be used with a vehicle equipped with a front or a rear single wheel. The wheel motor, as referred to herein, is designed as a vehicle power unit. The tire wheel assembly400, as illustrated inFIGS.45to47, includes the tire401that is a known air inflated tire, the wheel402fit in the tire401, and the rotating electrical machine500secured inside the wheel402. The rotating electrical machine500is equipped with a stationary portion including a stator and a rotating portion including a rotor. The rotating electrical machine500is firmly attached at the stationary portion to the vehicle body and also attached at the rotating portion to the wheel402. The tire401and the wheel402are rotated with rotation of the rotating portion of the rotating electrical machine500. The structure of the rotating electrical machine500including the stationary portion and the rotating portion will be described later in detail. The tire wheel assembly400also has peripheral devices: a suspension, a steering device, and a brake device mounted thereon. The suspension retains the tire wheel assembly400secured to a vehicle body, not shown. The steering device works to turn the tire wheel assembly400. The brake device works to apply a brake to the tire wheel assembly400. The suspension is implemented by an independent suspension, such as trailing arm suspension, a strut-type suspension, a wishbone suspension, or a multi-link suspension. In this embodiment, the suspension includes the lower arm411, the suspension arm412, and the spring413. The lower arm411extends toward the center of the vehicle body. The suspension arm412and the spring413extend vertically. The suspension arm412may be engineered as a shock absorber whose detailed structure will be omitted in the drawings. The lower arm411and the suspension arm412are joined to the vehicle body and also joined to the disc-shaped base plate405secured to the stationary portion of the rotating electrical machine500. The lower arm411and the suspension arm412are, as clearly illustrated inFIG.46, retained coaxially with each other by the rotating electrical machine500(i.e., the base plate405) using the support shafts414and415. The steering device may be implemented by a rack-and-pinion, a ball-and-nut steering system, a hydraulic power steering system, or an electronic power steering system. In this embodiment, the steering device is made up of the rack unit421and the tie rod422. The rack unit421is connected to the base plate405of the rotating electrical machine500through the tie rod422. Rotation of a steering shaft, not shown, will cause the rack unit421to be driven, thereby moving the tie rod422in a lateral direction of the vehicle. This causes the tire wheel assembly400to be turned around the lower arm411and the support shafts414and415of the suspension arm412, thereby changing the orientation of the tire wheel assembly400. The brake device may preferably be made of a disc brake or a drum brake. In this embodiment, the brake device includes the disc rotor431and the brake caliper432. The disc rotor431is secured to the rotating shaft501of the rotating electrical machine500. The brake caliper432is secured to the base plate405of the rotating electrical machine500. The brake caliper432has a brake pad which is hydraulically actuated and pressed against the disc rotor431to create a brake in the form of mechanical friction, thereby stopping rotation of the tire wheel assembly400. The tire wheel assembly400also has mounted thereon the storage duct440in which the electrical cable H1and the cooling pipe H2extending from the rotating electrical machine500are disposed. The storage duct440extends from an end of the stationary portion of the rotating electrical machine500parallel to an end surface of the rotating electrical machine500without physical interference with the suspension arm412and is firmly joined to the suspension arm412, thereby fixing a location of the joint of the storage duct440to the suspension arm412relative to the base plate405. This minimizes mechanical stress which arises from vibration of the vehicle and acts on the electrical cable H1and the cooling pipe H2. The electrical cable H1is electrically connected to a power supply, not shown, and an ECU, not shown, which are mounted in the vehicle. The cooling pipe H2is connected to a radiator, not shown. The structure of the rotating electrical machine500will be described below in detail. This embodiment will refer to an example where the rotating electrical machine500is designed as the in-wheel motor. The rotating electrical machine500is excellent in operation efficiency and output performance as compared with a conventional electrical motor of a power unit equipped with a speed reducer for use in vehicles. The rotating electrical machine500may alternatively be employed as an electrical motor in another application other than the power unit for vehicles if it may be produced at low cost. In such a case, the rotating electrical machine500ensures high performance. The operation efficiency, as referred to herein, represents an indication used in fuel economy tests in which automobiles are operated in given driving modes. The outline of the rotating electrical machine500is shown inFIGS.48to51.FIG.48is a side elevation of the rotating electrical machine500, as viewed in an axial direction of the rotating shaft501(i.e., from inside the vehicle).FIG.49is a longitudinal sectional view of the rotating electrical machine500, as taken along the line49-49inFIG.48.FIG.50is a transverse sectional view of the rotating electrical machine500, as taken along the line50-50inFIG.49.FIG.51is an exploded sectional view of the rotating electrical machine500. In the following discussion, a direction in which the rotating shaft501extends outside the vehicle body will be referred to as an axial direction, and a direction perpendicular to the length of the rotating shaft501will be referred to as a radial direction inFIG.51. InFIG.48, opposite directions extending in a circular form from a point on a center line which passes through the center of the rotating shaft501, in other words, the center of rotation of the rotating portion of the rotating electrical machine500and defines the cross section49of the rotating electrical machine500will be referred to as a circumferential direction. In other words, the circumferential direction is either a clockwise direction or a counterclockwise direction from a point on the cross section49. InFIG.49, the right side is an outer side of the vehicle, while the left side is an inner side of the vehicle. In other words, when the rotating electrical machine500is mounted in the vehicle, the rotor510which will be described later in detail is disposed closer to the outer side of the vehicle body than the rotor cover670is. The rotating electrical machine500in this embodiment is designed as an outer-rotor surface-magnet rotating electrical machine. The rotating electrical machine500includes the rotor510, the stator520, the inverter unit530, the bearing560, and the rotor cover670. These parts are each arranged coaxially with the rotating shaft501provided integrally with the rotor510and assembled in a given order in the axial direction to complete the rotating electrical machine500. In the rotating electrical machine500, the rotor510and the stator520are hollow cylindrical and face each other through an air gap. Rotation of the rotating shaft501causes the rotor510to rotate radially outside the stator520. The rotor510works as a field generator. The stator520works as an armature. The rotor510includes the hollow cylindrical rotor carrier511and the annular magnet unit512secured to the rotor carrier511. The rotating shaft501is firmly joined to the rotor carrier511. The rotor carrier511includes the cylindrical portion513. The magnet unit512is firmly attached to an inner circumferential surface of the cylindrical portion513. In other words, the magnet unit512is surrounded by the cylindrical portion513of the rotor carrier511from radially outside it. The cylindrical portion513has a first end and a second end which are opposed to each other in the axial direction. The first end faces the outside of the vehicle body. The second end faces the base plate405. In the rotor carrier511, the end plate514continues to the first end of the cylindrical portion513. In other words, the cylindrical portion513and the end plate514are formed or joined integrally with each other. The cylindrical portion513has an opening in the second end. The rotor carrier511may be made by a cold rolled steel plate having a high mechanical strength. For example, the rotor carrier511is made of SPCC (steel plate cold commercial) or SPHC (steel plate hot commercial) which has a thickness larger than SPCC. The rotor carrier511may alternatively be made of forging steel or carbon fiber reinforced plastic (CFRP). The length of the rotating shaft501is larger than a dimension of the rotor carrier511in the axial direction. In other words, the rotating shaft501protrudes from the open end of the rotor carrier511inwardly in the vehicle to have an end on which the brake device is mounted. The end plate514of the rotor carrier511has the center hole514apassing through a thickness thereof. The rotating shaft501passes through the hole514aof the end plate514and is retained by the rotor carrier511. The rotating shaft501has the flange502extending from a joint of the rotor carrier511to the rotating shaft501in a direction traversing or perpendicular to the length of the rotating shaft501. The flange502has a surface joined to an outer surface of the end plate514which faces outside the vehicle, so that the rotating shaft501is secured to the rotor carrier511. In the tire wheel assembly400, the wheel402is joined to the rotating shaft501using fasteners, such as bolts, extending from the flange502outwardly in the vehicle. The magnet unit512is made up of a plurality of permanent magnets which arranged adjacent each other and whose magnetic polarities are disposed alternately in a circumferential direction of the rotor510. The magnet unit512, thus, has a plurality of magnetic poles arranged in the circumferential direction. The permanent magnets are secured to the rotor carrier511using, for example, adhesive. The magnet unit512has the same structure as that of the magnet unit42discussed with reference toFIGS.8and9and is made of sintered neodymium magnets whose intrinsic coercive force is 400 [kA/m] or more and whose remanent flux density is 1.0 [T] or more. The magnet unit512is, like the magnet unit42inFIG.9, made of polar anisotropic magnets and includes the first magnets91and the second magnets92which are different in magnetic polarity from each other. As already described with reference toFIGS.8and9, in each of the magnets91and92, the direction of easy axis of magnetization in a region close to the d-axis is different from that of easy axis of magnetization in a region close to the q-axis. Specifically, in each of the magnets91and92, the easy axis of magnetization in the region close to the d-axis may be oriented nearly parallel to the d-axis, while the easy axis of magnetization in the region close to the q-axis may be oriented nearly perpendicular to the q-axis, thus creating arc-shaped magnetic paths. In each of the magnets91and92, the easy axis of magnetization in the region close to the d-axis may be oriented parallel to the d-axis, while the easy axis of magnetization in the region close to the q-axis may be oriented perpendicular to the q-axis. In brief, the magnet unit512is magnetically oriented to have the easy axis of magnetization in the region close to the d-axis (i.e., the center of the magnetic pole) which is oriented more parallel to the d-axis than in the region close to the q-axis (i.e., the boundary between the magnetic poles). Accordingly, the above-described structure of each of the magnets91and92functions to enhance the magnet magnetic flux thereof on the d-axis and reduce a change in magnetic flux near the q-axis. This enables the magnets91and92to be produced which have a smooth change in surface magnetic flux from the q-axis to the d-axis on each magnetic pole. The magnet unit512may be designed to have the same structure as that of the magnet unit42illustrated inFIGS.22and23or illustrated inFIG.30. The magnet unit512may be equipped with a rotor core (i.e., a back yoke) which is made of a plurality of magnetic steel plates stacked in the axial direction and arranged close to the cylindrical portion513of the rotor carrier511, i.e., near the outer circumference thereof. In other words, the rotor core may be disposed radially inside the cylindrical portion513of the rotor carrier511, and the permanent magnets (i.e., the magnets91and92) may be arranged radially inside the rotor core. Referring back toFIG.47, the cylindrical portion513of the rotor carrier511has formed therein the recesses513awhich are arranged at a given interval away from each other in the circumferential direction of the cylindrical portion513and extend in the axial direction of the cylindrical portion513. The recesses513aare made, for example, using, for example, a press. The cylindrical portion513, as can be seen inFIG.52, has convexities or protrusions513beach of which is formed on an inner circumference thereof in alignment with a respective one of the recesses513in the radial direction of the cylindrical portion513. The magnet unit512has formed in the outer circumference thereof the recesses512aeach of which is fit on a respective one of the protrusions513bof the cylindrical portion513. In other words, the protrusions513bof the cylindrical portion513are disposed in the recesses512a, thereby holding the magnet unit512from moving in the circumferential direction of the rotor carrier511. The protrusions513bof the rotor carrier511, thus, serve as stoppers to stop the magnet unit512from being rotated. The protrusions513bmay alternatively be formed in a known way other than the pressing techniques. FIG.52demonstrates magnetic paths which are produced by the magnets of the magnet unit512and indicated by arrows. Each of the magnetic paths extends in an arc-shape and crosses the q-axis that is located at the boundary between the magnetic poles. Each of the magnetic paths is oriented parallel or near parallel to the d-axis (i.e., the center of a corresponding magnetic pole) in the region close to the d-axis. The magnet unit512has the recesses512bwhich are formed in an inner circumferential surface thereof and located on the q-axis. The magnetic paths in the magnet unit512have lengths different between a region near the stator520(i.e., a lower side in the drawing) and a region far from the stator520(i.e., an upper side in the drawing). Specifically, the length of the magnetic path close to the stator520is shorter than that of the magnetic path far from the stator520. Each of the recesses512bis located on the shortest length of the magnetic path. In other words, to avoid having an insufficient amount of magnetic flux around the shorter magnetic path, the magnet unit512is shaped to have removed portions in which the magnetic flux would otherwise be weak. Generally, the effective magnetic flux density Bd of a magnet becomes high with an increase in length of a magnetic circuit passing through the magnet. The permeance coefficient Pc and the effective magnetic flux density Bd of the magnet have a relationship in which when one of them becomes high, the other also becomes high. The structure illustrated inFIG.52enables the volume of the magnets to be reduced with a minimized risk of decrease in permeance coefficient Pc that is an indication of the degree of the effective magnetic flux density of the magnets. On the B-H coordinate system, an intersection of a permeance straight line and a demagnetization curve is an operating point according to the configuration of a magnet. The magnetic flux density on the operating point represents the effective magnetic flux density Bd. The rotating electrical machine500in this embodiment is engineered to have the stator520in which the amount of iron is decreased and is highly effective in having the magnetic circuit crossing the q-axis. The recesses512bof the magnet unit512may be used as air paths extending in the axial direction, thereby enhancing the cooling ability of the rotating electrical machine500. Next, the structure of the stator520will be described below. The stator520includes the stator winding, i.e., the stator coil,521and the stator core522.FIG.53is an exploded view of the stator winding521and the stator core522. The stator winding521is made up of a plurality of phase-windings which are of a hollow cylindrical shape. The stator core522serving as a base member is arranged radially inside the stator winding521. In this embodiment, the stator winding521includes three-phase windings: a U-phase winding, a V-phase winding, and a W-phase winding. Each of the U-phase winding, the V-phase winding, and the W-phase winding is made of two layers of the conductor523: an outer layer and an inner layer located radially inside the outer layer. The stator520is, like the above-described stator50, designed to have a slot-less structure and the flattened stator winding521. The stator520, therefore, has substantially the same structure of the stator50illustrated inFIGS.8to16. The structure of the stator core522will be described below. The stator core522is, like the above-described stator core52, made of a plurality of magnetic steel plates stacked in the axial direction in the shape of a hollow cylinder having a given thickness in the radial direction. The stator winding521is mounted on a radially outer circumference of the stator core522which faces the rotor510. The stator core522does not have any substantial irregularities on the outer circumferential surface thereof. In the assembly of the stator core522and the stator winding521, the conductors523of the stator winding521are arranged adjacent each other in the circumferential direction on the outer circumferential surface of the stator core522. The stator core522functions as a back core. The stator520may be made to have one of the following structures:(A) The stator520has a conductor-to-conductor members each of which is disposed between the conductors523in the circumferential direction. As the conductor-to-conductor members, magnetic material is used which meets a relation of Wt×Bs Wm×Br where Wt is a width of the conductor-to-conductor members in the circumferential direction within one magnetic pole, Bs is the saturation magnetic flux density of the conductor-to-conductor members, Wm is a width of the magnet unit512equivalent to one magnetic pole in the circumferential direction, and Br is the remanent flux density in the magnet unit512.(B) The stator520has the conductor-to-conductor members each of which is disposed between the conductors523in the circumferential direction. The conductor-to-conductor members are each made of a non-magnetic material.(C) The stator520has no conductor-to-conductor member disposed between the conductors523in the circumferential direction. The above structure of the stator520results in a decrease in inductance as compared with typical rotating electrical machines equipped with teeth (i.e., iron core) which create a magnetic path between conductors of a stator winding. Specifically, the structure of the stator520enables the inductance to be one-tenth or less of that in the prior art structure. Usually, the reduction in inductance will result in a reduction in impedance. The rotating electrical machine500is, therefore, designed to increase output power relative to input power to increase the degree of output torque. The rotating electrical machine500is also enabled to produce a higher degree of output than rotating electrical machines which use a magnet-embedded rotor and output torque using impedance voltage (i.e., reluctance torque). In this embodiment, the stator winding521is formed along with the stator core522in the form of a single unit using a resinous molding material (i.e., insulating material). The molding material occupies an interval between a respective adjacent two of the conductors523arranged in the circumferential direction. This structure of the stator520is equivalent to that described in the above item (B). The conductors523arranged adjacent each other in the circumferential direction may have surfaces which face each other in the circumferential direction and are placed in direct contact with each other or opposed to each other through a small air gap therebetween. This structure is equivalent to the above item (C). When the structure in the above item (A) is used, the outer circumferential surface of the stator core522is preferably shaped to have protrusions in accordance with orientation of the conductors523in the axial direction, that is, a skew angle in a case where the stator winding521is of a skew structure. The structure of the stator winding521will be described below with reference toFIGS.54(a) and54(b). FIG.54(a)is a partially developed view which illustrates an assembly of the conductors523arranged in the form of an outer one of two layers overlapping each other in the radial direction of the stator winding521.FIG.54(b)is a partially developed which illustrates an assembly of the conductors523arranged in the form of an inner one of the two layers. The stator winding521is designed as an annular distributed winding. The stator winding521is made up of the conductors523arranged in the form of two layers: an outer layer and an inner layer overlapping each other in the radial direction of the stator winding521. The conductors523of the outer layer are, as can be seen inFIGS.54(a) and54(b), skewed at an orientation different from that of the conductors523of the inner layer. The conductors523are electrically insulated from each other. Each of the conductors523is, as illustrated inFIG.13, preferably made of an aggregation of wires86. For instance, two each of the conductors523through which current flows in the same direction for the same phase are arranged adjacent each other in the circumferential direction of the stator winding521. Accordingly, in the stator winding521, a respective circumferentially arranged two of the conductors523in each of the outer and inner layers, that is, a total four of the conductors523, constitutes one conductor portion of the stator winding521for each phase. The conductor portions are provided one in each magnetic pole. The conductor portion is preferably shaped to have a thickness (i.e., a dimension in the radial direction) which is less than a width thereof (i.e., a dimension in the circumferential direction) for each phase in each pole. In other words, the stator winding521is preferably designed to have a flattened conductor structure. For instance, a total eight of the conductors523: four arrayed adjacent each other in the circumferential direction in each of the outer and inner layers preferably define each conductor portion for each phase in the stator winding521. Alternatively, each of the conductors523may be shaped to have a transverse section, as illustrated inFIG.50, whose thickness (i.e., a dimension in the radial direction) may be larger than a width (i.e., a dimension in the circumferential direction). The stator winding521may alternatively be designed to have the same structure as that of the stator winding51shown inFIG.12. This structure, however, requires the rotor carrier511to have an inner chamber in which coil ends of the stator winding521are disposed. The stator winding521, as can be seen inFIG.54(a), has the coil side525which overlaps the stator core522in the radial direction thereof. The coil side525is made up of portions of the conductors523which obliquely extend or slant at a given angle to the axis of the stator winding521and are arranged adjacent each other in the circumferential direction. The stator winding521also has the coil ends526located outside the coil side525in the axial direction thereof. Each of the coil ends526is made up of portions of the conductors523which are turned inwardly in the axial direction to make joints of the conductors523of the coil side525. FIG.54(a)illustrates the coil side525and the coil ends526in the outer layer of the conductors523of the stator winding521. The conductors523of the inner layer and the conductors523of the outer layer are electrically connected together by the coil ends526. In other words, each of the conductors523of the outer layer is turned in the axial direction and leads to a respective one of the conductors523of the inner layer through the coil end526. In brief, a direction in which current flows in the stator winding521is reversed between the outer and inner layers of the conductors523connected to extend in the circumferential direction. The stator winding521has end regions defining ends thereof opposed to each other in the axial direction and an intermediate region between the end regions. Each of the conductors523has skew angles different between each of the end regions and the intermediate region. Specifically, the skew angle is an angle which each of the conductors523makes with a line extending parallel to the axis of the stator winding521. The conductors523, as illustrated inFIG.55, have the skew angle θs1in the intermediate region and the skew angle θs2in the end regions which is different from the skew angle θs1. The skew angle θs1is smaller than the skew angle θs2. The end regions of the stator winding521are defined to partially occupy the coil side525. The skew angle θs1and the skew angle θs2are angles at which the conductors523are inclined in the axial direction of the stator winding521. The skew angle θs1in the intermediate region is preferably selected to be an angle suitable for removing harmonic components of magnetic flux resulting from excitation of the stator winding521. The skew angle of each of the conductors523of the stator winding521is, as described above, selected to be different between the intermediate region and the end regions. The skew angle θs1in the intermediate region is set smaller than the skew angle θs2in the end regions, thereby decreasing the size of the coil ends526, but enabling a winding factor of the stator winding521to be increased. In other words, it is possible for the stator winding521to decrease the length of the coil ends526, i.e., portions of the conductors523extending outside the stator core522in the axial direction without sacrificing a desired winding factor, which enables the rotating electrical machine500to be reduced in size and the degree of torque to be increased. An adequate range of the skew angle θs1in the intermediate region will be discussed below. In the case where the X conductors523where X is the number of the conductors523are arranged in one magnetic pole of the stator winding521, excitation of the stator winding521is thought of as producing an Xthharmonic. If the number of phases is defined as S, and the number of the conductors523for each phase is defined as m, then X=2×S×m. The disclosers or inventors of this application have focused the fact that an Xthharmonic is equivalent to a combination of an (X−1)thharmonic and (X+1)thharmonic, and the Xthharmonic may be reduced by reducing at least either of the (X−1)thharmonic or the (X+1)thharmonic, and have found that the Xthharmonic will be reduced by selecting the skew angle θs1to fall in a range of 360°/(X+1) to 360°/(X−1) in terms of electrical angle. For instance, if S=3, and m=2, the skew angle θs1is determined to fall in a range of 360°/13 to 360°/11 in order to decrease the 12thharmonic (i.e., X=12). Specifically, the skew angle θs1is selected from a range of 27.7° to 32.7°. The skew angle θs1of each of the conductors523in the intermediate region determined in the above way will facilitate or enhance interlinkage of magnetic fluxes, as produced by N-poles and S-poles of the magnets arranged alternately, in the intermediate regions of the conductors523, thereby increasing the winding factor of the stator winding521. The skew angle θs2in the end regions is determined to be larger than the skew angle θs1in the intermediate region of the conductors523. The skew angle θs2is selected to meet a relation of θs1<θs2<90°. In the stator winding521, the end of each of the conductors523of the inner layer is joined to the end of a respective one of the conductors523of the outer layer by welding or bonding techniques. Alternatively, each of the conductors523of the inner layer and a respective one of the conductors523of the outer layer may be made by a single conductor with a curved or bent portion defining an end joint thereof. In the stator winding521, one of the ends of each phase winding, i.e., one of the axially opposed coil ends526of each phase winding is electrically connected to a power converter (i.e., an inverter) using, for example, a bus. The structure of the stator winding521in which the conductors523are joined together in ways different between the coil end526closer to the bus bar and the coil end526farther away from the bus bar will be described below. The conductors523of the stator winding521having the first structure are welded together at the coil ends526closer to the bus bars, while they are connected in a way other than welding at the coil ends526farther away from the bus bars. For instance, a single conductor may be shaped to have a curved or bent portion which defines the coil end523farther away from the bus bar and to make a respective two of the conductors523. The end of each phase winding is, as described above, welded to the bus bar at the coil end526closer to the bus bar. The coil ends526closer to the bus bars may, therefore, be welded together to connect the conductors523in a single step. This improves the efficiency in producing the stator winding521. The conductors523of the stator winding521having the second structure are connected in a way other than welding at the coil ends526closer to the bus bars and welded together at the coil ends526farther away from the bus bars. In a case where the conductors523are welded together at the coil ends526closer to the bus bars, it is necessary to increase an interval between the bus bars and the coil ends526in order to avoid a mechanical interference between the welds and the bus bars. The second structure, however, eliminates such a need and enables an interval between the bus bars and the coil ends526to be decreased, thereby loosing requirements for an axial dimension of the stator winding521or for the bus bars. The conductors523of the stator winging521having the third structure are jointed together at all the coil ends526using welding techniques. This structure enables each of the conductors523to be made of a shorter length of conductor than the above structures and also eliminates the need for bending or curving conductors to improve the efficiency in completing the stator winding521. The stator winding521having the fourth structure is completed without welding the coil ends526of all the conductors523. This minimizes or eliminates welded portions of the stator winding521, thereby minimizing a risk that electrical insulation of the conductors532may be damaged at welds. The stator winding521may be produced by preparing a weaved assembly of conductor strips placed horizontally and then bending them into a cylinder. In this case, the coil ends526of the conductor strips may be welded together before the conductor strips are bent. The bending of the conductor strips into a cylinder may be achieved by wrapping the assembly of the conductor strips about a circular cylinder which is identical in diameter with the stator core522or alternatively by wrapping the assembly of the conductor trips directly around the stator core522. The stator winding521may alternatively be designed to have one of the following structures. The stator winding521illustrated inFIGS.54(a) and54(b)may alternatively have the intermediate region and the end regions which are identical in skew angle with each other. The stator winding521illustrated inFIGS.54(a) and54(b)may alternatively have the conductors523which are arranged adjacent each other in the circumferential direction in the same phase and have ends joined together using connecting conductors extending perpendicular to the axial direction of the stator winding521. The stator winding521may be made in the form of (2×n) annular layers. For example, the stator winding521may be shaped to have 4 or 6 overlapping annular layers. The structure of the inverter unit530working as a power converter unit will be described below with reference toFIGS.56and57which are exploded sectional views.FIG.57illustrates two sub-assemblies of parts of the inverter unit530shown inFIG.56. The inverter unit530includes the inverter housing531, a plurality of electrical modules532disposed in the inverter housing531and the bus bar module533which electrically connects the electrical modules532together. The inverter housing531includes the hollow cylindrical outer wall541, the hollow cylindrical inner wall542, and the bossed member543. The inner wall542is smaller in outer diameter than the outer wall541and arranged radially inside the outer wall541. The bossed member543is secured to one of axially opposed ends of the inner wall542. These members541,542, and543are each preferably made of an electrically conductive material, such as carbon fiber reinforced plastic (CFRP). The inverter housing531has the outer wall541and the inner wall542overlapping each other in the radial direction thereof. The bossed member543is, as illustrated inFIG.57, attached to the axial end of the inner wall542inFIG.57. The stator core522is secured to an outer periphery of the outer wall541of the inverter housing531, thereby assembling the stator520and the inverter unit530as a single unit. The outer wall541, as illustrated inFIG.56, has a plurality of grooves or recesses541a,541b, and541cformed in an inner peripheral surface thereof. The inner wall542has a plurality of grooves or recesses542a,542b, and542cformed in an outer peripheral surface thereof. When the outer wall541and the inner wall542are assembled together, three inner chambers: the annular chambers544a,544b, and544care, as can be seen inFIG.57, defined by the recesses541a,541b, and541cand the recesses542a,542b, and542c. The annular chamber544blocated intermediate between the annular chambers544aand544cis used as the coolant path545through which cooling water or coolant flows. The annular chambers544aand544clocated axially outside the annular chamber544b(i.e., the coolant path545) have the sealing members546disposed therein. The sealing members546hermetically seal the annular chamber544b(i.e., the coolant path545). The coolant path545will also be discussed later in detail. The bossed member543includes the annular disc-shaped end plate547and the boss548protruding from the end plate547into the housing531. The boss548is of a hollow cylindrical shape. Specifically, the inner wall542has a first end and a second end which is opposed to the first end in the axial direction and closer to a protruding end of the rotating shaft501(i.e., the inside of the vehicle). The bossed member543is, as can be seen inFIG.51, secured to the second end of the inner wall542. In the tire wheel assembly400illustrated inFIGS.45to47, the base plate405is secured to the inverter housing531(more specifically, the end plate547of the bossed member543). The inverter housing531is of a double-walled structure made up of outer and inner peripheral walls overlapping each other in the radial direction of the inverter housing531. The outer peripheral wall of the inverter housing531is defined by a combination of the outer wall541and the inner wall542. The inner peripheral wall of the inverter housing531is defined by the boss548. In the following discussion, the outer peripheral wall defined by the outer wall541and the inner wall542will also be referred to as an outer peripheral wall WA1. The inner peripheral wall defined by the boss548will also be referred to as an inner peripheral wall WA2. The inverter housing531has an annular inner chamber which is defined between the outer peripheral wall WA1and the inner peripheral wall WA2and in which the electrical modules532are arranged adjacent each other in the circumferential direction thereof. The electrical modules532are firmly attached to an inner periphery of the inner wall542using adhesive or vises (i.e., screws). The inverter housing531will also be referred to as a housing member. The electrical modules532will also be referred to as electrical parts or electrical devices. The bearing560is disposed inside the inner peripheral wall WA2(i.e., the boss548). The bearing560retains the rotating shaft501to be rotatable. The bearing560is designed as a hub bearing which is disposed in the center of the wheel402to support the tire wheel assembly400to be rotatable. The bearing560is located to overlap the rotor510, the stator520, and the inverter unit530in the radial direction thereof. In the rotating electrical machine500of this embodiment, the above-described magnetic orientation of the rotor510enables the magnet unit512to have a decreased thickness. The stator520, as described above, has a slot-less structure and uses flattened conductors. This enables the magnetic circuit to have a thickness decreased in the radial direction, thereby increasing the volume of space radially inside the magnetic circuit. These arrangements enable the magnetic circuit, the inverter unit530, and the bearing560to be stacked in the radial direction. The boss548also serves as a bearing retainer in which the bearing560is disposed. The bearing560is implemented by, for example, a radial ball bearing, as can be seen inFIG.51, including the cylindrical inner race561, the cylindrical outer race561which is larger in diameter than the inner race561and arranged radially outside the inner race561, and the balls563disposed between the inner race561and the outer race562. The outer race562is fit in the bossed member543, thereby securing the bearing560to the inverter housing531. The inner race561is fit on the rotating shaft501. The inner race561, the outer race562, and the balls563are made of metallic material, such as carbon steel. The inner race561of the bearing560includes the cylinder561ain which the rotating shaft501is disposed and the flange561bwhich extends from an end of the cylinder561ain a direction perpendicular to the axis of the bearing560. The flange561bis placed in contact with an inner surface of the end plate514of the rotor carrier511. After the bearing560is mounted on the rotating shaft501, the rotor carrier511is retained or held between the flange502of the rotating shaft501and the flange561bof the inner race561. The angle (i.e.,900in this embodiment) which the flange503of the rotating shaft501makes with the axis of the rotating shaft501is identical with that which the flange561bof the inner race561makes with the axis of the rotating shaft501. The rotor carrier511is firmly held between the flanges502and561b. The rotor carrier511is supported by the inner race561of the bearing560from inside, thereby ensuring the stability in holding the rotor carrier511relative to the rotating shaft501at a required angle, which achieves a desired degree of parallelism of the magnet unit512to the rotating shaft501. This enhances the resistance of the rotor carrier511to mechanical vibration even though the rotor carrier511is designed to have a size increased in the radial direction. Next, the electrical modules532installed in the inverter housing531will be discussed below. The electrical modules532is made up of a plurality of modules each of which includes electrical devices, such as semiconductor switches, and smoothing capacitors which constitute a power converter. Specifically, the electrical modules532include the switch modules532A equipped with semiconductor switches (i.e., power devices) and the capacitor modules532B equipped with smoothing capacitors. A plurality of spaces549are, as illustrated inFIGS.49and50, secured to the inner peripheral surface of the inner wall542. The spaces549each have a flat surface to which one of the electrical modules532is attached. The inner peripheral surface of the inner wall542is curved, while each of the electrical modules532has a flat surface to be attached to the inner wall542. Each of the spaces549is, therefore, shaped to have the flat surface which faces away from the inner wall542. The electrical modules532are secured to the flat surfaces of the spacers549. The spacers549need not necessarily to be interposed between the inner wall542and the electrical modules532. For example, the inner wall542may be shaped to have flat sections. Alternatively, each of the electrical modules532may be shaped to have a curved surface attached directly to the inner wall542. The electrical modules532may alternatively be secured to the inverter housing531without contacting with the inner peripheral surface of the inner wall542. For instance, the electrical modules532may be fixed on the end plate547of the bossed member543. The switch modules532A may be secured to the inner peripheral surface of the inner wall542without contacting therewith. Similarly, the capacitor modules532B may be secured to the inner peripheral surface of the inner wall542without contacting therewith. In a case where the spacers549are disposed on the inner peripheral surface of the inner wall542, a combination of the outer peripheral wall WA1and the spacers549will be referred to as a cylindrical portion. Alternatively, in a case where the spacers549are not used, the outer peripheral wall WA1itself will be referred to as a cylindrical portion. The outer peripheral wall WA1of the inverter housing531, as described already, has formed therein the coolant path545in which cooling water flows to cool the electrical modules532. Instead of the cooling water, cooling oil may be used. The coolant path545is of an annular shape contoured to conform with the configuration of the outer peripheral wall WA1. The cooling water passes the electrical modules532from an upstream to a downstream side in the coolant path545. In this embodiment, the coolant path545extends in an annular shape and surrounds or overlaps the electrical modules532in the radial direction. The inner wall542has formed therein the inlet path571through which the cooling water is inputted into the coolant path545and the outlet path572through which the cooling water is discharged from the coolant path545. The inner wall542, as described already, has the electrical modules532disposed on the inner peripheral surface thereof. Only one of intervals each between a respective circumferentially adjacent two of the electrical modules532is shaped to be larger than the others. In such a large interval, a portion of the inner wall542protrudes radially inwardly to form the bulging portion573. The bulging portion573has formed therein the inlet path571and the outlet path572which are arranged adjacent each other in the circumferential direction of the inner wall542. FIG.58illustrates the layout of the electrical modules532in the inverter housing531.FIG.58represents the same longitudinal section of the rotating electrical machine500as inFIG.50. The electrical modules32are, as can be seen inFIG.58, arranged at the first interval INT1or the second interval INT2away from each other in the circumferential direction of the rotating electrical machine500. Only selected two of the electrical modules532are, as clearly illustrated inFIG.58, located at the second interval INT2away from each other. The second interval INT2is selected to be larger than the first interval INTL. Each of the intervals INT1and INT2is, for example, a distance between the centers of an adjacent two of the electrical modules532arranged in the circumferential direction. The bulging portion573is located in the interval INT2between the electrical modules532. In other words, the intervals between the electrical modules532include a longer interval (i.e., the second interval INT2) in which the bulging portion573lies. Each of the intervals INT1and INT2may be given by an arc-shaped distance between the two adjacent electrical modules532along a circle around the center defined on the rotating shaft501. Each of the intervals INT1and INT2may alternatively be expressed, as illustrated inFIG.58, by an angular interval θi1or θi2around the center defined on the rotating shaft501where θi1<θi2. In the structure illustrated inFIG.58, the electrical modules532are placed without contacting with each other in the circumferential direction of the rotating electrical machine500, but however, they may be arranged in contact with each other in the circumferential direction except for the second interval INT2. Referring back toFIG.48, the end plate547of the bossed member543has formed therein the inlet/outlet port574in which ends of the inlet path571and the outlet path572are formed. The inlet path571and the outlet path572connect with the circulation path575through which the cooling water is circulated. The circulation path575is defined by a coolant pipe. The circulation path575has the pump576and the heat dissipating device577installed therein. The pump576is actuated to circulate the cooling water in the coolant path545and the circulation path575. The pump576is implemented by an electrically powered pump. The heat dissipating device577is made of a radiator working to release thermal energy of the cooling water to air. The stator520is, as illustrated inFIG.50, arranged outside the outer peripheral wall WA1. The electrical modules532are arranged inside the outer peripheral wall WA1. Accordingly, thermal energy generated by the stator520is transferred to the outer peripheral wall WA1from outside, while thermal energy generated by the electrical modules532is transferred to the outer peripheral wall WA1from inside. The cooling water flowing through the coolant path545, therefore, simultaneously absorbs the thermal energy generated by both the stator520and the electrical modules532, thereby facilitating dissipation of heat from the rotating electrical machine500. The electrical structure of the power converter will be described below with reference toFIG.59. The stator winding521is, as illustrated inFIG.59, made up of a U-phase winding, a V-phase winding, and a W-phase winding. The stator winding521connects with the inverter600. The inverter600is made of a bridge circuit having as many upper and lower arms as the phases of the stator winding521. The inverter600is equipped with a series-connected part made up of the upper arm switch601and the lower arm switch602for each phase. Each of the switches601and602is turned on or off by a corresponding of the driver circuits603to energize or deenergize a corresponding one of the phase windings. Each of the switches601and602is made of, for example, a semiconductor switch, such as a MOSFET or IGBT. The capacitor604is also connected to each of the series-connected parts made up of the switches601and602to output electrical charge required to achieve switching operations of the switches601and602. The control device607serves as a controller and is made up of a microcomputer equipped with a CPU and memories. The control device607analyzes information about parameters sensed in the rotating electrical machine500or a request for a motor mode or a generator mode in which the rotating electrical machine500operates to control switching operations of the switches601and602to excite or deexcite the stator winding521. For instance, the control device607performs a PWM operation at a given switching frequency (i.e., carrier frequency) or an operation using a rectangular wave to turn on or off the switches601and602. The control device607may be designed as a built-in controller installed inside the rotating electrical machine500or an external controller located outside the rotating electrical machine500. The rotating electrical machine500in this embodiment has a decreased electrical time constant because the stator520is engineered to have a decreased inductance. It is, therefore, preferable to increase the switching frequency (i.e., carrier frequency) and enhance the switching speed in the rotating electrical machine500. In terms of such requirements, the capacitor604serving as a charge supply capacitor is connected parallel to the series-connected part made up of the switches601and602for each phase of the stator winding521, thereby reducing the wiring inductance, which deals with electrical surges even through the switching speed is enhanced. The inverter600is connected at a high potential terminal thereof to a positive terminal of the dc power supply605and at a low potential terminal thereof to a negative terminal (i.e., ground) of the dc power supply605. The smoothing capacitor606is connected to the high and low potential terminals of the inverter600in parallel to the dc power supply605. Each of the switch modules532A includes the switches601and602(i.e., semiconductor switching devices generating heat), the driver circuits603(i.e., electric devices constituting the driver circuits603), and the charge supply capacitor604. Each of the capacitor modules532B includes the smoothing capacitor606generating heat. The structure of the switch modules532A is shown inFIG.60. Each of the switch modules532A, as illustrated inFIG.60, includes the module case611, the switches601and602for one of the phases of the stator winding521, the driver circuits603, and the charge supply capacitor604. Each of the driver circuits603is made of a dedicated IC or a circuit board and installed in the switch module532A. The module case611is made from insulating material, such as resin. The module case611is secured to the outer peripheral wall WA1with a side surface thereof contacting the inner peripheral surface of the inner wall542of the inverter unit530. The module case611has, for example, resin molded therein. In the module case611, the switches601and602, the driver circuits603, and the capacitor604are electrically connected together using wires612. The switch modules532A are, as described above, attached to the outer peripheral wall WA1through the spacers549, but however,FIG.60emits the spacers549for the brevity of illustration. In a condition where the switch modules532A are firmly attached to the outer peripheral wall WA1, a portion of each of the switch modules532A, which is located closer to the outer peripheral wall WA1, i.e., the coolant path545, is more cooled. In terms of such ease of cooling, the order in which the switches601and602, the driver circuits603, and the capacitor604are arranged is determined. Specifically, the switches601and602have the largest amount of heat generation. The capacitor604has an intermediate amount of heat generation. The driver circuits603have the smallest amount of heat generation. Accordingly, the switches601and602are located closest to the outer peripheral wall WA1. The driver circuits603are located farther away from the outer peripheral wall WA1. The capacitor604is interposed between the switches601and602and the driver circuit603. In other words, the switches601and602, the capacitor604, the driver circuits603are arranged in this order close to the outer peripheral wall WA1. An area of each of the switch modules532A which is attached to the inner wall542is preferably smaller in size than an area of the inner peripheral surface of the inner wall542which is contactable with the switch modules532A. Although not illustrated in detail, the capacitor modules532B have the capacitor606disposed in a module case similar in configuration and size to the switch modules532A. Each of the capacitor modules532B is, like the switch modules532A, secured to the outer peripheral wall WA1with the side surface of the module case611placed in contact with the inner peripheral surface of the inner wall542of the inverter housing531. The switch modules532A and the capacitor modules532B need not necessarily be arranged coaxially with each other inside the outer peripheral wall WA1of the inverter housing531. For instance, the switch modules532A may alternatively be disposed radially inside or outside the capacitor modules532B. When the rotating electrical machine500is operating, the switch modules532A and the capacitor modules532B transfer heat generated therefrom to the coolant path545through the inner wall542of the outer peripheral wall WA1, thereby cooling the switch modules532A and the capacitor modules532B. Each of the electrical modules532may be designed to have formed therein a flow path into which coolant is delivered to cool the electrical module532. The cooling structure of the switch modules532A will be described below with reference toFIGS.61(a) and61(b).FIG.61(a)is a longitudinal sectional view of each of the switch modules532A along a line passing through the outer peripheral wall WA1.FIG.61(b)is a sectional view taken along the line61B-61B inFIG.61(a). Like inFIG.60, the switch module532A, as illustrated inFIGS.61(a) and61(b), includes the module case611, the switches601and602for a corresponding one of the phases of the stator winding521, the driver circuits603, the capacitor604, and a cooling device made of a pair of pipes621and622and the coolers623. The pipe621of the cooling device is designed as an inlet pipe through which cooling water is delivered from the coolant path545in the outer peripheral wall WA1to the coolers623. The pipe622of the cooling device is designed as an outlet pipe through which the cooling water is discharged from the coolers623to the coolant path545. The cooler623is provided for an object to be cooled. The cooling device may, therefore, be designed to have a single cooler623or a plurality of coolers623. In the structure shown inFIGS.61(a) and61(b), the two coolers623are arranged at a given interval away from each other in a direction perpendicular to the length of the coolant path545, in other words, the radial direction of the inverter unit530. The pipes621and622connect with the coolers623. Each of the coolers623has an inner void. Each of the coolers623may be equipped with inner fins for enhancing the cooling ability. In the structure equipped with the two coolers623which will also be referred to as a first cooler623and a second cooler623where the first cooler623is located closer to the outer peripheral wall WA1than the second cooler623is, a first space between the first cooler623and the outer peripheral wall WA1, a second space between the first and second coolers623, and a third space located inside the second cooler623away from the outer peripheral wall WA1are locations where electrical devices are disposed. The second space, the first space, and the third space have a higher degree of cooing ability in this order. In other words, the second space is a location which has the highest degree of cooling ability. The first space close to the outer peripheral wall WA1(i.e., the coolant path545) is higher in cooling ability than the third space farther away from the outer peripheral wall WA1. In view of this relation in cooled capability, the switches601and602are arranged in the second space between the first and second coolers623. The capacitor604is arranged in the first space between the first cooler623and the outer peripheral wall WA1. The driver circuits603are arranged in the third space located farther away from the outer peripheral wall WA1. Although not illustrated, the driver circuits603may alternatively be disposed in the first space, while the capacitor604may be disposed in the third space. In either case, in the module case611, the switches601and602are electrically connected to the driver circuits603using the wires612, while the switches601and602are connected to the capacitor604using the wires612. The switches601and602are located between the driver circuits603and the capacitor604, so that the wires612extending from the switches601and602to the driver circuit603are oriented in a direction opposite a direction in which the wires612extending from the switches601and602to the capacitor604. The pipes621and622are, as can be seen inFIG.61(b), arranged adjacent each other in the circumferential direction, that is, from an upstream side to a downstream side of the coolant path545. The cooling water, therefore, enters the coolers623from the pipe621located on the upstream side and is then discharged from the pipe622located on the downstream side. The stopper624is preferably disposed between the inlet pipe621and the outlet pipe621in the coolant path545to stop flow of the cooling water in order to facilitate entry of cooling water into the cooling device. The stopper624may be designed as a shutter or block to close the coolant path545or an orifice to decrease a transverse sectional area of the coolant path545. FIGS.62(a) to62(c)illustrate a modified form of the cooling structure of the switch modules532A.FIG.62(a)is a longitudinal section of the switch module532A along a line traversing the outer peripheral wall WA1.FIG.62(b)is a sectional view taken along the line62B-62B inFIG.62(a). The structure inFIGS.62(a) and62(b)has the inlet pipe621and the outlet pipe622which are different in layout from those illustrated inFIGS.62(a) and62(b). Specifically, the inlet and outlet pipes621and622are arranged adjacent each other in the axial direction. The coolant path545, as clearly illustrated inFIG.62(c), includes an inlet section leading to the inlet pipe621and an outlet section leading to the outlet pipe622. The inlet section and the outlet section are physically separate from each other in the axial direction and hydraulically connected through the pipes621and622and the coolers623. Each of the switch modules532A may alternatively be designed to have one of the following structures. The structure inFIG.63(a)is, unlike inFIG.61(a), equipped with the single cooler263. In the module case611, a space (which will be referred to as a first space) between the cooler623and the outer peripheral wall WA1in the radial direction of the module case611has a higher degree of cooled capability. A space (which will be referred to as a second space) located inside the cooler623farther away from the outer peripheral wall WA1has a lower degree of cooled capability. In view of this relation in cooled capability, the structure inFIG.63(a)has the switches601and602arranged in the first space close to the outer peripheral wall WA1outside the cooler623. The capacitor604is arranged in the second space located inside the cooler623. The driver circuits603are disposed farther away from the cooler623. Each of the switch modules532A is, as described above, designed to have the switches601and602, the driver circuits603, and the capacitor604disposed within the module case611for one of the phases of the stator winding521, but may be modified to have the switches601and602and the driver circuits603or the capacitor604disposed in the module case611for one of the phases of the stator winding521. InFIG.63(b), the module case611has the inlet pipe621, the outlet pipe622, and the two coolers623mounted therein. One of the coolers623located closer to the outer peripheral wall WA1will be referred to as a first cooler. One of the coolers623located farther away from the outer peripheral wall WA1will be referred to as a second cooler. The switches601and602are arranged between the first and second coolers623. The capacitor604or the driver circuits603are arranged close to the outer peripheral wall WA1outside the first cooler623. The switches601and602and the driver circuit603are assembled as a single semiconductor module which is disposed in the module case611along with the capacitor604. In the structure of the switch module532A illustrated inFIG.63(b), the capacitor604is located outside or inside one of the first and second coolers623on the opposite side of the one of the first and second coolers623to the switches601and602. In the illustrated example, the capacitor604is located between the first cooler623and the outer peripheral wall WA1. The switch module532A may alternatively be designed to have two capacitors604disposed on the both sides of the first cooler623in the radial direction of the stator winding521. The structure in this embodiment delivers cooling water into only the switch modules532A other than the capacitor module532B through the coolant path545, but may alternatively be designed to supply the cooling water to both the modules532A and532B through the coolant path545. It is also possible to bring cooling water into direct contact with the electrical modules532to cool them. For instance, the electrical modules532may be, as illustrated inFIG.64, embedded in the outer peripheral wall WA1to achieve a direct contact of the outer surface of the electrical modules532with the cooling water. In this case, each of the electrical modules532may be partially exposed to the cooling water flowing in the coolant path545. Alternatively, the coolant path545may be shaped to have a size increased to be larger than that inFIG.58in the radial direction to arrange the electrical modules532fully within the coolant path545. In the case where the electrical modules532are embedded in the coolant path545, the module case611of each of the electrical modules532may be equipped with fins disposed in the coolant path545, that is, exposed to the cooling water to enhance the ability to cool the electrical modules532. The electrical modules532, as described above, include the switch modules532A and the capacitor modules532B which are different in amount of heat generation from the switch modules532A. In terms of such a difference, it is possible to modify the layout of the electrical modules532in the inverter housing531in the following way. For instance, the switch modules532A are, as illustrated inFIG.65, arranged away from each other in the circumferential direction of the stator520and located as a whole closer to the upstream side of the coolant path545(i.e., the inlet path571) than to the downstream side (i.e., the outlet path572) of the coolant path545. The cooling water entering the inlet path571is first used to cool the switch modules532A and then used to cool the capacitor modules532B. In the structure illustrated inFIG.65, the inlet and outlet pipes621and622are, like inFIGS.62(a) and62(b), arranged adjacent each other in the axial direction, but however, may be, like inFIGS.61(a) and61(b), oriented adjacent each other in the circumferential direction. The electrical structure of the electrical modules532and the bus bar module533will be described below.FIG.66is a transverse section taken along the line66-66inFIG.49.FIG.67is a transverse section taken along the line67-67inFIG.49.FIG.68is a perspective view which illustrates the bus bar module533. Electrical connections of the electrical modules532and the bus bar module533will be discussed with reference toFIGS.66to68. The inverter housing531has the three switch modules532A (which will also be referred to below as a first module group) which are, as illustrated inFIG.66, arranged adjacent each other circumferentially next to the bulging portion573on the inner wall542in which the inlet path571and the outlet path572are formed in communication with the coolant path545. The six capacitor modules532B are also arranged circumferentially adjacent each other next to the first module group. In summary, the inverter housing531has ten regions (i.e., the number of the modules532A and532B plus one) defined on the inner peripheral surface of the outer peripheral wall WA1. The ten regions are arranged adjacent each other in the circumferential direction of the inverter housing531. The electrical modules532are disposed, one in each of ninth of the regions, while the bulging portion573occupies the remaining one of the regions. The three switch modules532A will also be referred to as a U-phase module, a V-phase module, and a W-phase module. Each of the electrical modules532(i.e., the switch modules532A and the capacitor modules532B) is, as illustrated inFIGS.66,56, and57, equipped with a plurality of module terminals615extending from the module case611. The module terminals615serve as input/output terminals through which electrical signals are inputted into or outputted from the electrical modules532. The module terminals615each have a length extending in the axial direction of the inverter housing531. More specifically, the module terminals615, as can be seen inFIG.51, extend from the module case611toward the bottom of the rotor carrier511(i.e., the outside of the vehicle). The module terminals615of the electrical modules532are connected to the bus bar module533. The switch modules532A and the capacitor modules532B are different in number of the module terminals615from each other. Specifically, each of the switch modules532A is equipped with the four module terminals615, while each of the capacitor modules532B is equipped with the two module terminals615. The bus bar module533, as clearly illustrated inFIG.68, includes the annular ring631, the three external terminals632, and the winding connecting terminals633. The external terminals632extend from the annular ring631and achieve connections with external devices, such as a power supply and an ECU (Electronic Control Unit). The winding connecting terminals633are connected to ends of the phase windings of the stator winding521. The bus bar module533will also be referred to as a terminal module. The annular ring631is located radially inside the outer peripheral wall WA1of the inverter housing531and adjacent one of axially opposed ends of each of the electrical modules532. The annular ring631includes an annular body made from an insulating material, such as resin, and a plurality of bus bars embedded in the annular body. The bus bars connect with the module terminals615of the electrical modules532, the external terminals632, and the phase windings of the stator winding521, which will be also described later in detail. The external terminals632include the high-potential power terminal632A connecting with a power unit, the low-potential power terminal632B connecting with the power unit, and the single signal terminal632C connecting with the external ECU. The external terminals632(i.e.,632A to632C) are arranged adjacent each other in the circumferential direction of the annular ring631and extend in the axial direction of the annular ring631radially inside the annular ring631. The bus bar module533is, as illustrated inFIG.51, mounted in the inverter housing531together with the electrical modules532. Each of the external terminals632has an end protruding outside the end plate547. Specifically, the end plate547of the bossed member543, as illustrated inFIGS.56and57, has the hole547aformed therein. The cylindrical grommet635is fit in the hole547a. The external terminals632pass through the grommet635. The grommet635also functions as a hermetically sealing connector. The winding connecting terminals633connect with ends of the phase windings of the stator winding521and extend radially outward from the annular ring631. Specifically, the winding connecting terminals633include the winding connecting terminal633U connecting with the end of the U-phase winding of the stator winding521, the winding connecting terminal633V connecting with the end of the V-phase winding of the stator winding521, and the winding connecting terminal633W connecting with the end of the W-phase winding of the stator winding521. Each of the winding connecting terminals633is, as illustrated inFIG.70, the current sensor634which measure an electrical current flowing through a corresponding one of the U-phase winding, the V-phase winding, and the W-phase winding. The current sensor634may be arranged outside the electrical module532around the winding connecting terminal633or installed inside the electrical module532. Connections between the electrical modules532and the bus bar module533will be described below in detail with reference toFIGS.69and70. FIG.69is a development view of the electrical modules532which schematically illustrates electrical connections of the electrical modules532with the bus bar module533.FIG.70is a view which schematically illustrates electrical connections of the electrical modules532arranged in an annular shape with the bus bar module533. InFIG.69, power supply lines are expressed by solid lines, while signal transmission lines are expressed by chain lines.FIG.70shows only the power supply lines. The bus bar module533includes the first bus bar641, the second bus bar642, and the third bus bars643as power supply bus bars. The first bus bar641is connected to the high-potential power terminal632A. The second bus bar642is connected to the low-potential power terminal632B. The three third bus bars643are connected to the U-phase winding connecting terminals633U, the V-phase winding connecting terminals633V, and the W-phase winding connecting terminals633W. The winding connecting terminals633and the third bus bars643usually generate heat due to the operation of the rotating electrical machine10. A terminal block, not shown, may, therefore, be disposed between the winding connecting terminals633and the third bus bars643in contact with the inverter housing531equipped with the coolant path545. Alternatively, the winding connecting terminals633and/or the third bus bars643may be bent in a crank form to achieve physical contact with the inverter housing531equipped with the coolant path545. The above structure serves to release heat generated by the winding connecting terminals633or the third bus bars643to cooling water flowing in the coolant path545. FIG.70depicts the first bus bar641and the second bus bar642as completely circular bus bars, but however, may alternatively be of a C-shape. Each of the winding connecting terminals633U,633V, and633W may alternatively be connected directly to a corresponding one of the switch modules532A (i.e., the module terminals615) without use of the bus bar module533. Each of the switch modules532A is equipped with the four module terminals615including a positive terminal, a negative terminal, a winding terminal, and a signal terminal. The positive terminal is connected to the first bus bar641. The negative terminal is connected to the second bus bar642. The winding terminal is connected to one of the third bus bars643. The bus bar module533is also equipped with the fourth bus bars644as signal transmission bus bars. The signal terminal of each of the switch modules532A is connected to one of the fourth bus bars644. The fourth bus bars644are connected to the signal terminal632C. In this embodiment, each of the switch modules532A receives a control signal transmitted from an external ECU through the signal terminal632C. Specifically, the switches601and602in each of the switch modules532A are turned on or off in response to the control signal inputted through the signal terminal632C. Each of the switch modules532A is, therefore, connected to the signal terminal632C without passing through a control device installed in the rotating electrical machine500. The control signals may alternatively be, as illustrated inFIG.71, produced by the control device of the rotating electrical machine500and then inputted to the switch modules532A. The structure ofFIG.71has the control board651on which the control device652is mounted. The control device652is connected to the switch modules532A. The signal terminal632C is connected to the control device652. For instance, an external ECU serving as a host control device outputs a command signal associated with the motor mode or the generation mode to the control device652. The control device652then controls on-off operations of the switches601and602of each of the switch modules532A. In the inverter unit530, the control board651may be arranged closer to the outside of the vehicle (i.e., the bottom of the rotor carrier511) than the bus bar module533is. The control board651may alternatively be disposed between the electrical modules532and the end plate547of the bossed member543. The control board651may be located to overlap at least a portion of each of the electrical modules532in the axial direction. Each of the capacitor modules532B is equipped with two module terminals615serving as a positive terminal and a negative terminal. The positive terminal is connected to the first bus bar641. The negative terminal is connected to the second bus bar642. Referring back toFIGS.49and50, the inverter housing531has disposed therein the bulging portion573which is equipped with the inlet path571and the outlet path572for cooling water. The inlet path571and the outlet path572are aligned with the electrical modules532arranged adjacent each other in the circumferential direction of the inverter housing531. The external terminals632are arranged adjacent the bulging portion573in the radial direction of the inverter housing531. In other words, the bulging portion573and the external terminals632are located at the same angular position in the circumferential direction of the inverter housing531. In this embodiment, the external terminals632are disposed radially inside the bulging portion573. As the inverter housing531is viewed from inside the vehicle, the inlet/outlet port574and the external terminals632are, as clearly illustrated inFIG.48, aligned with each other in the radial direction of the end plate547of the bossed member543. The bulging portion573and the external terminals632are arranged adjacent the electrical modules532in the circumferential direction, thereby enabling the inverter unit530to be reduced in size, which also enables the rotating electrical machine500to be reduced in size. Referring back to the structure of the tire wheel assembly400inFIGS.45and47, the cooling pipe H2is joined to the inlet/outlet port574. The electrical cable H1is joined to the external terminals632. The electrical cable H1and the cooling pipe H2are arranged inside the storage duct440. In the inverter housing531, the three switch modules532A are arranged adjacent each other next to the external terminals632in the circumferential direction. The six capacitor modules532B are arranged next to the array of the switch modules532A in the circumferential direction. Such layout may be modified in the following way. For instance, the array of the three switch modules532A may be arranged at a location farthest away from the external terminals632, that is, diametrically opposed to the external terminals632across the rotating shaft501. Alternatively, the switch modules532A may be arranged at an increased interval away from each other in the circumferential direction, so that the capacitor modules532B may be disposed between the switch modules532A. The layout of the switch modules532A located farthest away from the external terminals632, that is, diametrically opposed to the external terminals632across the rotating shaft501minimizes a risk of failure in operation of the switch modules532A caused by mutual inductance between the external terminals632and the switch modules532A. Next, the structure of the resolver660working as an angular position sensor will be described below. The inverter housing531, as illustrated inFIGS.49to51, has disposed therein the resolver660which measures the electrical angle θ of the rotating electrical machine500. The resolver660functions as an electromagnetic induction sensor and includes the resolver rotor661secured to the rotating shaft501and the resolver stator662which radially faces an outer circumference of the resolver rotor661. The resolver rotor661is made of a ring-shaped disc fit on the rotating shaft501coaxially with the rotating shaft501. The resolver stator662includes the circular stator core663and the stator coil664wound around teeth of the stator core663. The stator coil664includes a single-phase exciting coil and two-phase output coils. The exciting coil of the stator coil664is energized by a sine wave excitation signal to generate magnetic flux which interlinks with the output coils. This causes a positional relation of the exciting coil with the two output coils to be changed cyclically as a function of an angular position of the resolver rotor661(i.e., a rotation angle of the rotating shaft501), so that the number of magnetic fluxes interlining with the output coils is changed cyclically. In this embodiment, the exciting coil and the output coils are arranged so that voltages, as developed at the output coils, are out of phase by π/2. Output voltage generated by the output coils will, therefore, be waves derived by modulating the excitation signal with modulating waves sin θ and cos θ. Specifically, if the excitation signal is expressed by sin Ωt, the modulated waves will be sin (θ×sin Ωt) and cos (θ×sin Ωt). The resolver660is equipped with a resolver digital converter. The resolver digital converter works to perform wave detection using the modulated wave and the excitation signal to calculate the electrical angle θ. For instance, the resolver660is connected to the signal terminal632C. An output of the resolver digital converter is inputted to an external device through the signal terminal632C. In a case where a control device is installed in the rotating electrical machine500, the output of the resolver digital converter, which represents the calculated result, is inputted to the control device. Next, the structure of the resolver660installed in the inverter housing531will be described below. The bossed member543of the inverter housing531, as illustrated inFIGS.49and51, has formed thereon the hollow cylindrical boss548. The boss548has the protrusion548aformed on an inner periphery thereof in the shape of an inner shoulder. The protrusion548aprojects in a direction perpendicular to the axial direction of the inverter housing531. The resolver stator662is secured using screws in contact with the protrusion548a. In the boss548, the bearing650is arranged on an opposite side of the protrusion548ato the resolver660. Within the boss548, the housing cover666is arranged on an opposite side of the resolver660to the protrusion548ain the axial direction. The housing cover666is made of an annular ring-shaped disc and closes an inner chamber of the boss548in which the resolver660is disposed. The housing cover666is made from an electrically conductive material, such as a carbon fiber reinforced plastic (CFRP). The housing cover666has formed in the center thereof the center hole666athrough which the rotating shaft501passes. The center hole666a, as clearly illustrated inFIG.49, has disposed therein the sealing member667which hermetically seal an air gap between the center hole666aand the outer periphery of the rotating shaft501. The sealing member667hermetically seals the inner chamber of the boss548in which the resolver660is disposed. The sealing member667may be designed as a slidable seal made from resin. The inner chamber in which the resolver660is disposed is surrounded or defined by the annular boss548of the bossed member543and which has axially-opposed ends closed by the bearing560and the housing cover666. The outer circumference of the resolver660is, therefore, surrounded by the conductive material, thereby minimizing adverse effects of electromagnetic noise on the resolver660. The inverter housing531is, as described above inFIG.57, designed to have a double-walled structure equipped with the outer peripheral wall WA1and the inner peripheral wall WA2. The stator520is arranged radially outside the outer peripheral wall WA1. The electrical modules532are arranged between the outer peripheral wall WA1and the inner peripheral wall WA2. The resolver660is disposed radially inside the inner peripheral wall WA2. The inverter housing531is made from conductive material. The stator520and the resolver660are, therefore, isolated from each other through a conductive wall (i.e., a conductive double wall), that is, the outer peripheral wall WA1and the inner peripheral wall WA2, thereby minimizing a risk of magnetic interference between the stator520(i.e., the magnetic circuit) and the resolver660. The rotor cover670which is arranged in the open end of the rotor carrier511will be described below in detail. The rotor carrier511, as illustrated inFIGS.49and51, has the end open in the axial direction. The rotor cover670which is made of a substantially ring-shaped disc is disposed on the open end, i.e., partially covers the open end. The rotor cover670is secured to the rotor carrier511using, for example, welding techniques or vises (i.e., screws). The rotor cover670is preferably shaped to have a portion smaller in size (i.e. diameter) than the inner periphery of the rotor carrier511to hold the magnet unit512from moving in the axial direction. The rotor cover670has an outer diameter identical with that of the rotor carrier511, but has an inner diameter slightly greater than an outer diameter of the inverter housing531. The outer diameter of the inverter housing531is equal to the inner diameter of the stator520. The stator520is, as described above, attached to the outer circumference of the inverter housing531. Specifically, the stator520and the inverter housing531joined together. The inverter housing531has a portion protruding in the axial direction from the joint of the stator520and the inverter housing531. Such a protrusion of the inverter housing531is, as clearly illustrated inFIG.49, surrounded by the rotor cover670. The sealing member671is disposed between the inner circumference of the rotor cover670and the outer periphery of the inverter housing531to hermetically seal an air gap therebetween. The sealing member671, therefore, hermetically closes an inner chamber of the rotor cover670in which the magnet unit512and the stator520are disposed. The sealing member671may be made of a slidable seal made from resin. The above embodiment offers the following beneficial advantages. The rotating electrical machine500has the outer peripheral wall WA1of the inverter housing531arranged radially inside the magnetic circuit made up of the magnet unit512and the stator winding521and also has the coolant path545formed in the outer peripheral wall WA1. The rotating electrical machine500also has the plurality of electrical modules532arranged along the inner circumference of the outer peripheral wall WA1. This enables the magnetic circuit, the coolant path545, and the power converter to be arranged in a stacked shape in the radial direction of the rotating electrical machine500, thereby permitting an axial dimension of the rotating electrical machine500to be reduced and also achieving effective layout of parts in the rotating electrical machine500. The rotating electrical machine500also ensures the stability in cooling the electrical modules532composing the power converter, thereby enabling the rotating electrical machine500to operate with high efficiency and to be reduced in size thereof. The electrical modules532(i.e., the switch modules532A and the capacitor modules532B) equipped with heat generating devices, such as semiconductor switches or capacitors are placed in direct contact with the inner peripheral surface of the outer peripheral wall WA1, thereby causing heat, as generated by the electrical modules532, to be transferred to the outer peripheral wall WA1, so that the electrical modules532are well cooled. In each of the switch modules532A, the coolers623are disposed outside the switches601and602. In other words, the switches601and602are arranged between the coolers623. The capacitor604is placed on an opposite side of at least one of the coolers623to the switches601and602, thereby enhancing the cooling of the capacitor604as well as the switches601and602. In each of the switch modules532A, the coolers623are, as described above, placed on both sides of the switches601and602. The driver circuit603is arranged on an opposite side of at least one of the coolers623to the switches601and602, while the capacitor604is arranged on the other opposite side of the cooler623, thereby enhancing the cooling of the driver circuit603and the capacitor604as well as the switches601and602. For instance, each of the switch modules532A is designed to have the coolant path545which delivers cooling water into the modules to cool the semiconductor switches. Specifically, each module532A is cooled by the outer peripheral wall WA1through which the cooling water passes and also by the cooling water flowing in the module532A. This enhances the cooling of the switch modules532A. The rotating electrical machine500is equipped with a cooling system in which cooling water is delivered into the coolant path545from the external circulation path575. The switch modules532A are placed on an upstream side of the coolant path545close to the inlet path571, while the capacitor modules532B are arranged downstream of the switch modules532A. Generally, the cooling water flowing through the coolant path545has a lower temperature on the upstream side than the downstream side. The switch modules532A are, therefore, cooled better than the capacitor modules532B. The electrical modules532are, as described above, arranged at shorter intervals (i.e., the first intervals INT1) or a longer interval (i.e., the second interval INT2) away from each other in the circumferential direction of the rotating electrical machine500. In other words, the intervals between the electrical modules532include a single longer interval (i.e., the second interval INT2). The bulging portion573which is equipped with the inlet path571and the outlet path572lies in the longer interval. These arrangements enable the inlet path571and the outlet path572of the coolant path545to be arranged radially inside the outer peripheral wall WA1. Usually, it is required to increase the volume or flow rate of cooling water in order to enhance the cooling efficiency. Such a requirement may be met by increasing an area of an opening of each of the inlet path571and the outlet path572. This is achieved in this embodiment by placing the bulging portion573in the longer interval (i.e., the second interval INT2) between the electrical modules532, which enables the inlet path571and the outlet path572to be shaped to have required sizes. The external terminals632of the bus bar module533are arranged adjacent the bulging portion573in the radial direction of the rotor510radially inside the outer peripheral wall WA1. In other words, the external terminals632is placed together with the bulging portion573within the larger interval (i.e., the second interval INT2) between the electrical modules532arranged adjacent each other in the circumferential direction of the rotor510. This achieves a suitable layout of the external terminals632without physical interference with the electrical modules532. The outer-rotor type rotating electrical machine500is, as described above, engineered to have the stator520attached to the radially outer circumference of the outer peripheral wall WA1and also have the plurality of electrical modules532arranged radially inside the outer peripheral wall WA1. This layout causes heat generated by the stator520to be transferred to the outer peripheral wall WA1from radially outside and also causes heat generated by the electrical modules532to be transferred to the outer peripheral wall WA1from radially inside. The stator520and the electrical modules532are simultaneously cooled by cooling water flowing through the coolant path545, thereby facilitating dissipation of thermal energy generated by heat-producing parts installed in the rotating electrical machine500. The electrical modules532arranged radially inside the outer peripheral wall WA1and the stator winding521arranged radially outside the outer peripheral wall WA1are electrically connected together using the winding connecting terminals633of the bus bar module533. The winding connecting terminals633are disposed away from the coolant path545in the axial direction of the rotating electrical machine500. This facilitates electrical connections of the electrical modules532to the stator winding521even in a structure in which the coolant path545extends in an annular form in the outer peripheral wall WA1, in other words, the outside and the inside of the outer peripheral wall WA1are isolated from each other by the coolant path545. The rotating electrical machine500in this embodiment is designed to have a decreased size of teeth or no teeth (i.e., iron cores) between the conductors523of the stator520arranged adjacent each other in the circumferential direction to reduce a limitation on a torque output which results from magnetic saturation occurring between the conductors532. The rotating electrical machine500also has the conductors523of a thin flat shape to enhance a degree of torque output. This structure enables a region radially inside the magnetic circuit to be increased in size by reducing the thickness of the stator520without altering the outer diameter of the rotating electrical machine500. The region is used to have the outer peripheral wall WA1equipped with the coolant path545disposed therein and enables the electrical modules532to be placed radially inside the outer peripheral wall WA1. The rotating electrical machine500is equipped with the magnet unit512in which magnet-produced magnetic fluxes are concentrated on the d-axis to enhance a degree of output torque. Such a structure of the magnet unit512enables a radial thickness thereof to be reduced and the region radially inside the magnetic circuit to be, as described above, increased in volume thereof. The region is used to have the outer peripheral wall WA1with the coolant path545disposed therein and also have the plurality of electrical modules532to be placed radially inside the outer peripheral wall WA1. The region also be used to have the bearing560and the resolver660arranged therein in addition to the magnetic circuit, the outer peripheral wall WA1, and the electrical modules532. The tire wheel assembly400using the rotating electrical machine500as an in-wheel motor is attached to the vehicle body using the base plate405secured to the inverter housing531and a mount mechanism, such as suspensions. The rotating electrical machine500is designed to have a reduced size, thus occupying a decreased size of space in the vehicle body. This enables the volume of space required for installation of a power unit, such as a storage battery in the vehicle or the volume of a passenger compartment of the vehicle to be increased. Modified forms of the in-wheel motor will be described below. First Modification of In-Wheel Motor The rotating electrical machine500has the electrical modules532and the bus bar module533arranged radially inside the outer peripheral wall WA1of the inverter unit530and also has the stator520arranged radially outside the outer peripheral wall WA1. Locations of the bus bar modules533relative to the electrical modules532are optional. The phase windings of the stator winding521may be connected to the bus bar module533radially across the outer peripheral wall WA1using winding connecting wires (e.g., the winding connecting terminals633) whose locations are optional. For example, the bus bar module533or the winding connecting wires may be arranged in the following layouts. (α1) The bus bar module533may be located closer to the outer side of the vehicle, that is, the bottom of the rotor carrier511than the electrical modules532are in the axial direction of the rotating electrical machine500. (α2) The bus bar module533may be located closer to the inner side of the vehicle, that is, farther away from the rotor carrier511than the electrical modules532is in the axial direction. The winding connecting wires may be placed on the following location. (β1) The winding connecting wires may be arranged close to the outer side of the vehicle, that is, the bottom of the rotor carrier511in the axial direction of the rotating electrical machine500. (β2) The winding connecting wires may be located closer to the inner side of the vehicle, that is, further from the rotor carrier511. Four types of locations of the electrical modules532, the bus bar module533, and the winding connecting wires will be described below with reference toFIGS.72(a) to72(d). FIGS.72(a) to72(d)are longitudinal sectional views which partially illustrate modified forms of the rotating electrical machine500. The same reference numbers as employed in the above embodiments refer to the same parts, and explanation thereof in detail will be omitted here. The winding connecting wires637are electrical conductors connecting of the phase windings of the stator winding521with the bus bar module533and correspond to the above-described winding connecting terminals633. In the structure illustrated inFIG.72(a), a locational relation of the bus bar module533to the electrical modules532corresponds to the above-described layout (α1). The winding connecting wires637are arranged in the above layout (β1). Specifically, connections of the electrical modules532to the bus bar module533and connections of the stator winding521to the bus bar module533are made on the outer side of the vehicle (i.e., close to the bottom of the rotor carrier511). This layout is identical with that inFIG.49. The structure inFIG.72(a)enables the coolant path545to be formed in the outer peripheral wall WA1without any physical interference with the winding connecting wires637and also facilitates the layout of the winding connecting wires637connecting the stator winding521and the bus bar module533together. In the structure illustrated inFIG.72(b), a locational relation of the bus bar module533to the electrical modules532corresponds to the above-described layout (α1). The winding connecting wires637are arranged in the above layout (β2). Specifically, connections of the electrical modules532to the bus bar module533are made on the outer side of the vehicle (i.e., close to the bottom of the rotor carrier511), while the stator winding521and the bus bar module533are connected close to the inner side of the vehicle (i.e., further from the rotor carrier511). The structure inFIG.72(b)enables the coolant path545to be formed in the outer peripheral wall WA1without any physical interference with the winding connecting wires637. In the structure illustrated inFIG.72(c), a locational relation of the bus bar module533to the electrical modules532corresponds to the above-described layout (α2). The winding connecting wires637are arranged in the above layout (β1). Specifically, connections of the electrical modules532to the bus bar module533are made on the inner side of the vehicle (i.e., further from the bottom of the rotor carrier511), while the stator winding521and the bus bar module533are connected close to the outer side of the vehicle (i.e., closer to the rotor carrier511). In the structure illustrated inFIG.72(d), a locational relation of the bus bar module533to the electrical modules532corresponds to the above-described layout (α2). The winding connecting wires637are arranged in the above layout (β2). Specifically, connections of the electrical modules532to the bus bar module533and connections of the stator winding521to the bus bar module533are made on the inner side of the vehicle (i.e., further from the bottom of the rotor carrier511). The structure inFIG.72(c)or72(d) in which the bus bar module533is arranged farther away from the rotor carrier511than the electrical modules532, thereby facilitating layout of electrical wires leading to, for example, an electrical device, such as a fan motor, if installed in the rotor carrier511. The structure also enables the bus bar module533to be placed close to the resolver660mounted closer to the inner side of the vehicle than the bearings563are, thereby facilitating layout of electrical wires leading to the resolver660. Second Modification of In-Wheel Motor Modified forms of a mount structure of the resolver rotor661will be described below. Specifically, the rotating shaft501, the rotor carrier511, and the inner race561of the bearing560are rotated together in the form of a rotating unit. The structure in which the resolver rotor611is mounted to the rotating unit will be described below. FIGS.73(a) to73(c)are structural views which illustrate modifications of the mount structure for attaching the resolver rotor661to the rotating unit. In any of the modifications, the resolver660is arranged within a hermetically sealed space which is surrounded by the rotor carrier511and the inverter housing531and protected from splashing of water or mud.FIG.73(a)shows the same structure of the bearing560as that inFIG.49. The structures inFIGS.73(b) and73(c)have the bearing560which is different in structure from that illustrated inFIG.49and arranged away from the end plate514of the rotor carrier511.FIGS.73(a) to73(c)each demonstrate two available locations where the resolver rotor661is mounted. Although not clearly illustrated, the boss548of the bossed member543may be extended to or near the outer circumference of the resolver rotor661to have the resolver stator662secured to the boss548. In the structure illustrated inFIG.73(a), the resolver rotor661is attached to the inner race561of the bearing560. Specifically, the resolver rotor661is secured to a surface of the flange561bof the inner race561which faces in the axial direction or an end surface of the cylinder561aof the inner race561which faces in the axial direction. In the structure illustrated inFIG.73(b), the resolver rotor661is attached to the rotor carrier511. Specifically, the resolver rotor661is secured to an inner peripheral surface of the end plate514of the rotor carrier511. The rotor carrier511has the hollow cylinder515extending from an inner circumferential edge of the end plate514along the rotating shaft501. The resolver rotor661may alternatively be secured to an outer periphery of the cylinder515of the rotor carrier511. In the latter case, the resolver rotor661is disposed between the end plate514of the rotor carrier511and the bearing560. In the structure illustrated inFIG.73(c), the resolver rotor661is attached to the rotating shaft501. Specifically, the resolver rotor661is mounted on the rotating shaft501between the end plate514of the rotor carrier511and the bearing560or on the opposite side of the bearing560to the rotor carrier511. Third Modification of In-Wheel Motor Modified structures of the inverter housing531and the rotor cover670will be described below with reference toFIGS.74(a) and74(b), which are longitudinal sectional view schematically illustrating the structure of the rotating electrical machine500. The same reference number as employed in the above embodiments refer to the same parts. The structure inFIG.74(a)substantially corresponds to that illustrated inFIG.49. The structure inFIG.74(b)substantially corresponds to a partially modified form of that inFIG.74(a). In the structure illustrated inFIG.74(a), the rotor cover670secured to an open end of the rotor carrier511. The rotor cover670surrounds the outer peripheral wall WA1of the inverter housing531. In other words, the rotor cover670has an inner circumferential end surface facing the outer peripheral surface of the outer peripheral wall WA1. The sealing member671is disposed between the inner circumferential end surface of the rotor cover670and the outer peripheral surface of the outer peripheral wall WA1. The housing cover666is disposed inside the boss548of the inverter housing531. The sealing member667is disposed between the housing cover666and the rotating shaft501. The external terminals632of the bus bar module533extend through the wall of the inverter housing531downward, as viewed inFIG.74(a). The inverter housing531has formed therein the inlet path571and the outlet path572which communicate with the coolant path545. The inverter housing531has also formed thereon the inlet/outlet port574in which open ends of the inlet path571and the outlet path572lie. In the structure illustrated inFIG.74(b), the inverter housing531(i.e., the bossed member543) has the annular protrusion681formed thereon in the shape of a flange. The annular protrusion681extends substantially parallel to the rotating shaft501inwardly in the inverter housing531(i.e., in the vehicle). The rotor cover670surrounds the protrusion681of the inverter housing531. In other words, the rotor cover670has an inner end surface facing the outer periphery of the protrusion681. The sealing member671is interposed between the inner end surface of the rotor cover670and the outer periphery of the protrusion681. The external terminals632of the bus bar module533extend through the wall of the boss548of the inverter housing531into the inner space of the boss548and also pass through the wall of the housing cover666toward the inside of the vehicle (downward, as viewed inFIG.74(b)). The inverter housing531has formed therein the inlet path571and the outlet path572which communicate with the coolant path545. The inlet path571and the outlet path572extend to the inner periphery of the boss548and then connect with the connecting pipes682which extend inwardly through the wall of the housing cover666(i.e., downward as viewed inFIG.74(b)). Portion of the pipes682extending inside the housing cover666(i.e., toward the inside of the vehicle) serve as the inlet/outlet port574. The structure inFIG.74(a)or74(b) hermetically seals the inner space of the rotor carrier511and the rotor cover670and achieves smooth rotation of the rotor carrier511and the rotor cover670relative to the inverter housing531. Particularly, the structure inFIG.74(b)is designed to have the rotor cover670which is smaller in inner diameter than that inFIG.74(a). The inverter housing531and the rotor cover670are, therefore, laid to overlap each other in the axial direction of the rotating shaft501inside the electrical modules532in the vehicle, thereby minimizing a risk of adverse effects of electromagnetic noise in the electrical modules532. The decreased inner diameter of the rotor cover670results in a decrease in diameter of a sliding portion of the sealing member671, thereby reducing mechanical loss of rotation of the sliding portion. Fourth Modification of In-Wheel Motor A modification of the structure of the stator winding521will be described below with reference toFIG.75. The stator winding521is, as clearly illustrated inFIG.75, made of conductors which are shaped to have a rectangular transverse section and wave-wound with a long side thereof extending in the circumferential direction of the stator winding521. Each of the three-phase conductors532of the stator winding521has coil ends and coil sides. The coil sides are arranged at a given interval away from each other and connected together by the coil ends. The coil sides of the conductors523which are arranged adjacent each other in the circumferential direction of the stator winding521have side surfaces which face in the circumferential direction and placed in contact with each other or at a small interval away from each other. The coil ends of each of the phase windings of the stator winding521are bent in the radial direction. Specifically, the stator winding521(i.e., the conductors523) is bent inwardly in the radial direction at locations which are different among the U-, V-, and W-phase windings and away from each other in the axial direction, thereby avoiding physical interference with each other. In the illustrated structure, the coil ends of the conductors523of the U-, V-, and W-phase windings are, as described above, bent at right angles inwardly in the radial direction of the stator winding521at locations axially offset from each other by a distance equivalent to the thickness of the conductors523. The coil sides of the conductors523which are arranged adjacent each other in the circumferential direction have lengths which extend in the axial direction and are preferably identical with each other. The production of the stator520in which the stator core522is installed in the stator winding521may be achieved by preparing the hollow cylindrical stator winding521which has a slit to make end surfaces facing in the circumferential direction, in other words, to make the stator winding521in a substantially C-shape, fitting the stator core522inside an inner periphery of the stator winding521, and then joining the facing end surfaces to complete the stator winding521of a complete hollow cylindrical shape. Alternatively, the stator520may be produced by preparing the stator core522made of three discrete core sections arranged adjacent each other in the circumferential direction and then placing the core sections inside the inner periphery of the hollow cylindrical stator winding521. Other Modifications The rotating electrical machine500is, as illustrated inFIG.50, designed to have the inlet path571and the outlet path572of the coolant path545which are collected in one place. This layout may be modified in the following way. For instance, the inlet path571and the outlet path572may be placed at locations separate from each other in the circumferential direction of the rotating electrical machine500. Specifically, the inlet path571and the outlet path572may be arranged at an angular interval of 180° away from each other in the circumferential direction, in other words, diametrically opposed to each other. At least one of the inlet path571and the outlet path572may be made up of a plurality of discrete paths. The tire wheel assembly400in this embodiment is designed to have the rotating shaft501protruding in one of axially opposite directions of the rotating electrical machine500, but however, the rotating shaft501may alternatively have end portions protruding in axial opposite directions. This is suitable for vehicles equipped with a single front or a single rear wheel. The rotating electrical machine500may alternatively be designed to have an inner rotor-structure for use in the tire wheel assembly400. Modification 15 Each of the above embodiments has the sealing members57that cover the stator coil51and occupy a region including all of the conductor groups81radially outside the stator core52, in other words, lie in a region where the thickness of the sealing members57is larger than that of the conductor groups81in the radial direction. This layout of the sealing members57may be modified as a modification 15. The following describes this modification 15. For example, as illustrated inFIG.76, the outer peripheral surface of the stator core52, which serves as a base member, is shaped as a smooth flat surface.FIG.26has an upper direction that is a direction closer to the rotor40and farther from the stator core52, and a lower direction that is a direction closer to the stator core52and farther from the rotor40. An insulating sheet1000, which serves as a filmy sheet member, is mounted on the entire outer peripheral surface of the stator core52to cover the entire outer peripheral surface thereof. The insulating sheet1000is arranged to extend throughout the outer peripheral surface of the stator core52in the axial direction thereof. The insulating sheet1000is made of thermoplastic resin as non-magnetic material. Foamable resin is preferably used as material of the insulating sheet1000. Each of the conductor groups81has a stator-core side peripheral surface (i.e., a base-member side peripheral surface)1082aand a rotor side peripheral surface (i.e., a field-generator side peripheral surface)1082bin the radial direction of the stator core52. The insulating sheet1000has a rotor-side peripheral surface (i.e., a field-generator side peripheral surface)1001. Each of the conductor groups81serving as the conductive members has at least radial part embedded in the insulating sheet1000to thereby arrange the stator-core side peripheral surface1082ato be radially closer to the stator core52than the rotor-side peripheral surface1001is. The arrangement of the at least radial part of each of the conductor groups81embedded in the insulating sheet1000causes the rotor side peripheral surface1082bof each of the conductor groups81to(i) Project to be radially closer to the rotor40than the rotor-side peripheral surface1001of the insulating sheet1000is(ii) Be exposed That is, a part of each conductor group81is embedded in the insulating sheet1000to protrude radially inward in the insulating sheet1000. In particular, the stator50has the insulating sheet1000radially interposed between the stator core52and the conductor groups81. This prevents the conductor groups81from being in direct contact with the stator core52. The insulating sheet1000has portions, each of which is arranged between a corresponding adjacent pair of conductor groups81in the circumferential direction of the stator core52. That is, the insulating sheet1000has projections1002each formed to radially project between a corresponding adjacent pair of conductor groups81in the circumferential direction of the stator core52. Next, the following schematically describes a method of manufacturing the stator50with reference toFIGS.77(a) and77(b). The method performs a step of preparing an insulating sheet1000and a flat plate2000, which is made of magnetic material, and performs, as illustrated inFIG.77(a), a step of covering an outer surface of the flat plate2000with the insulating sheet1000; this step corresponds to a first step. Next, the method prepares conductor groups81, and mounts the conductor groups81on an outer surface (i.e., a top surface inFIG.77(a)) of the insulating sheet1000while arranging the conductor groups81thereon with regular intervals therebetween. Thereafter, the method performs a step of embedding at least part of each of the conductor groups81into the insulating sheet1000to thereby fastening the conductor groups81to the flat plate2000via the insulating sheet1000; this step corresponds to a second step. For example, the second step can press the conductor groups81mounted on the outer surface of the insulating sheet1000toward the flat plate2000(see the direction of arrow inFIG.77(b)) under a high temperature condition to thereby appropriately embed the conductor groups81in the insulating sheet1000. In place of pressing the conductor groups81mounted on the outer surface of the insulating sheet1000toward the flat plate2000, the method can simply mount the conductor groups81on the outer surface of the insulating sheet1000under a high temperature condition. Because the insulating sheet1000is made of foamable thermoplastic resin, a part of each conductor group81mounted on the outer surface of the insulating sheet1000under a high temperature condition is embedded in the insulating sheet1000under the own weight of the corresponding conductor group81. Because the insulating sheet1000is made of foamable thermoplastic resin, when a part of each conductor group81is embedded in the insulating sheet1000, a part of the insulating sheet1000may project between each adjacent pair of conductor groups81. That is, the second step, i.e., embedding step, enables projections1002to be each likely to be formed between a corresponding adjacent pair of conductor groups81; each of the projections1002projects between the corresponding adjacent pair of conductor groups81. The high temperature condition represents a temperature condition enough to deform the insulating sheet1000made of thermoplastic resin when pressure due to, for example, the weight of each conductor group81is applied on the insulating sheet1000, such as a temperature condition higher than or equal to the melting point of the material of the insulating sheet1000. Next, the method performs a step of rolling the flat plate2000with the conductor groups81being secured thereto via the insulating film1000to thereby form a hollow cylindrical stator core52; the step corresponds to a third step. This finally results in the stator50having the tubular cylindrical stator core52illustrated inFIG.76being manufactured. The modification 15, which employs the above configuration set forth above, offers the following beneficial advantages. Each of the conductor groups81has at least part embedded in the insulating sheet1000in the radial direction to thereby arrange the stator-core side peripheral surface1082ato be radially closer to the stator core52than the rotor-side peripheral surface1001is. This results in portions, more specifically, the projections1002, of the insulating sheet1000each being formed to radially project between a corresponding adjacent pair of conductor groups81in the circumferential direction of the stator core52. This prevents rotation of the conductor groups81relative to the stator core52. Additionally, the insulating sheet1000fastens the stator-core side peripheral surface1082aand circumferential-side surfaces1082cof each conductor group81. This restricts radial and circumferential movement of each conductor group81, making it possible to properly fix the conductor groups81to the stator core52. The insulating sheet1000enables the conductor groups81and the stator core52to be electrically isolated from each other, resulting in reduction in iron loss, such as eddy-current loss. The rotor side peripheral surface1082bof each of the conductor groups81to(i) Project to be radially closer to the rotor40than the rotor-side peripheral surface1001of the insulating sheet1000is(ii) Be exposed This results in an air gap between the rotor40and the stator50being reduced. The outer peripheral surface of the stator core52to which the conductor groups81are fastened via the insulating sheet1000is shaped as a flat surface without any irregularities. This results in easier manufacturing of the insulating sheet1000. The flat-shaped outer peripheral surface of the stator core52enables the insulating sheet1000to cover the outer peripheral surface of the stator core52without any space therebetween. The flat-shaped outer peripheral surface of the stator core52additionally results in easier attachment of the insulating sheet1000to the flat-shaped outer peripheral surface of the stator core52. Using foamable thermoplastic resin as material of the insulating sheet1000enables each conductor group81mounted on the outer surface of the insulating sheet1000under a high temperature condition in the second step of manufacturing the stator50to be at least partially embedded in the insulating sheet1000. The second step in the method of manufacturing the stator50presses the conductor groups81mounted on the outer surface of the insulating sheet1000toward the flat plate2000. Adjusting pressing force of the conductor groups81enables the amount of a part of each conductor group81embedded in the insulating film1000to be adjusted. Because the conductor groups81are arranged on the flat plate2000, the second step can uniformly press the conductor groups81. This results in an easier setting of a constant radial distance (i.e., a constant radial dimension, that is, a constant radial thickness) for each conductor group81from the outer peripheral surface52of the stator core52to the rotor-side peripheral surface82aof the corresponding conductor group81. Rolling the flat plate2000with the conductor groups81being secured thereto via the insulating film1000forms a hollow cylindrical stator core52. This results in an easier manufacturing of the stator core52as compared with manufacturing the stator core52by attaching the conductor groups81on the outer peripheral surface of a hollow cylindrical base for the stator core52. This additionally results in an easier setting of a constant radial dimension, i.e., a constant radial thickness, of each conductive member. Other Changes of Modification 15 The method described in the modification 15 performs the step of rolling the flat plate2000to which the conductor groups81have been secured, but can perform a step of rolling the flat plate2000to which no conductor groups81have been mounted to thereby form a hollow cylindrical base, and thereafter perform a step of securely mounting the conductor groups81to the outer peripheral surface of the hollow cylindrical base, thus manufacturing the hollow cylindrical stator core52. The conductor groups81according to the modification 15 are arranged to project more nearly to the rotor40as compared with the insulating sheet1000. This arrangement can be modified such that a minimum distance of the insulating sheet1000from the rotor-side peripheral surface1001to the rotor40and a minimum distance of each conductor group81from the rotor-side peripheral surface1082bto the rotor are substantially identical to each other. The stator50according to the modification 15 can be applied to an inner rotor type rotating electrical machine. In this situation, the conductor groups81are secured to the inner peripheral surface of the stator core52via the insulating sheet1000. The modification 15 uses the stator core52having a hollow cylindrical shape, but can use the stator core52having a cylindrical shape. The outer peripheral surface of the stator core52according to the modification 15 can have projections and depressions thereon. That is, projections, each of which is located between a corresponding adjacent pair of conductor groups81, can be mounted as inter-conductor members. Each of the projections, i.e., the inter-conductor members, is made of any one of a magnetic material and a non-magnetic material. The magnetic material preferably satisfies the following relation: Wt×Bs≤Wm×Br where(1) Wt represents a total circumferential width of one or more of the projections (inter-conductor members) lying within a range of one of the magnetic poles of the magnet unit(2) Bs represents a saturation magnetic flux density of the projections (inter-conductor members)(3) Wm represents a circumferential width of a portion of the magnet unit equivalent to one of the magnetic poles of the magnet unit(4) Br represents the remanent flux density of the magnet unit The controllers and methods described in the embodiments and their modifications can be implemented by a dedicated computer including a memory and a processor programmed to perform one or more functions embodied by one or more computer programs. The controllers and methods described in the embodiments and their modifications can also be implemented by a dedicated computer including a processor comprised of one or more dedicated hardware logic circuits. The controllers and methods described in the embodiments and their modifications can further be implemented by a processor system comprised of a memory, a processor programmed to perform one or more functions embodied by one or more computer programs, and one or more hardware logic circuits. The one or more programs can be stored in a non-transitory storage medium as instructions to be carried out by a computer or a processor. The disclosure of the specification is not limited to the disclosed embodiments. The disclosure of the specification can include not only the disclosed embodiments but also skilled-person's modifications based on the disclosed embodiments. For example, the disclosure of the specification is not limited to combinations of the components and/or elements disclosed in the disclosed embodiments, and therefore can be implemented by various combinations within the disclosed embodiments. The disclosure of the specification can include additional elements to the disclosed embodiments. The disclosure of the specification can include the disclosed embodiments from which one or more components and/or elements have been removed. The disclosure of the specification can include replacement of one or more elements or components in one of the disclosed embodiments with one or more elements or components in another one of the disclosed embodiments. The disclosure of the specification can include combinations of one or more elements or components in one of the disclosed embodiments with one or more elements or components in another one of the disclosed embodiments. The disclosed technical scopes of the disclosure of the specification are not limited to the descriptions of the disclosed embodiments. Some of the disclosed technical scopes of the disclosure of the specification are shown by the descriptions of claims, and various changes of the disclosed technical scopes within the equivalent meanings and/or equivalent scopes of the descriptions of the claims should be therefore accepted. While illustrative embodiments of the present disclosure have been described herein, the present disclosure is not limited to the embodiments described herein, but includes any and all embodiments having modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alternations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. | 316,758 |
11863032 | DETAILED DESCRIPTION The disclosure provides electric machines, and in particular improved multiple-rotor electric machines such as motors and generators. In some embodiments, the machines described herein can provide improved operational characteristics and durability. In various aspects, for example, the disclosure provides electric motors and generators having a plurality of magnetized rotors, which may include or be in the form of single bi-pole magnets (i.e., two-pole rotors). The rotors are configured to drive and/or be driven by a common shaft, for example by suitable combinations and configurations of gears. In some embodiments, the rotors are magnetically indexed, in pairs, with respect to each other and to corresponding electrical windings such that, when a current is passed through the one or more windings, the rotors provide phased rotary power to the common shaft. Alternatively, when torque is applied to the common shaft or gears connected thereto, a phased electrical output may be provided to the windings. In some embodiments, the rotors are magnetically indexed along different planes perpendicular to the axial direction of the common shaft, and connected by common rotor shafts. That is, all of the rotors in a first plane may share a common phase, and all of the rotors in a second plane may share a common phase which is offset from the phase of the first plane. In some embodiments, there may be 3 planes each offset by 120 degrees. Any suitable number of planes may be used with suitable offsets. Various aspects of preferred embodiments of electric machines according to the disclosure are described herein with reference to the drawings. Electric machines may have more than one rotor. An example of a multi-rotor electric machine is provided in U.S. Pat. No. 8,232,700 B2, the contents of which are hereby incorporated by reference in their entirety. FIG.1is a schematic perspective view of portions of an embodiment of an electric machine100having multiple rotors (also referred to herein as a “multi-rotor electric machine”). As illustrated, machine100comprises magnetic rotors102, windings108, stators122, and shaft104. In the embodiment shown, machine100comprises a plurality of magnetic rotors102, each configured to rotate about an independent rotor shaft116. Each rotor shaft116is configured to, under the impetus of magnetic rotors102, drive shaft104via gears118and central gear120when machine100is operated as a motor and an electric current is applied to windings108. Alternatively, magnetic rotors102are configured to rotate, and thus cause the flow of electric current in windings108, when a torque is applied to shaft104, such that machine100acts as a generator. It should be appreciated that gears118are shown without teeth inFIGS.2and3for the sake of clarity. Gears118may be provided in any suitable form, including, for example, toothless wheels engaged by friction. In the embodiment shown, each rotor shaft is supported by front and back plates with suitable bearings (not shown), and is formed integral with or otherwise connected to a drive gear118, which is configured to engage a central gear120. In some embodiments, central gear120is formed integral with or otherwise connected to shaft104, such that rotation of one or more rotors102causes drive gears118to drive central gear120, and therefore shaft104, into rotation. In some embodiments, rotors102are configured to operate in electromagnetically independent pairs. That is, rotors102a,102bcan be grouped magnetically into independent pairs160, such that there is no provision of magnetic material linking any two pairs160a,160bof rotors together, and the links between separate rotor pairs160are the gears118or other mechanical couplings between them, and possibly a shared electric phase. The rotors102a,102bin a given pair160can benefit from the provision of common magnetic circuit components, such as stators122and/or windings108. Such a configuration can reduce the amount of magnetic material required for operation of the rotors, with corresponding cost and weight savings. In the embodiment shown inFIG.3, each rotor102comprises one or more magnets mounted on a rotor shaft116and retained, particularly when rotating, by containment sheath126. Magnets128comprise north and south poles (denoted “N” and “S” respectively in the figures). In some embodiments, rotors102are bi-pole rotors. In some embodiments, rotors102a,102bin a given pair are indexed such that magnets128are mounted, and rotate, (a) as individual rotors102, in a desired phase with respect to their pair mates102a,102b, and (b) by pairs160, in a desired paired phase with respect to other pairs160and winding(s)108. Advantages associated with this configuration are explained in U.S. Pat. No. 8,232,700, the contents of which are incorporated by reference. Windings108may be provided in any configuration suitable for use in accomplishing the purposes described herein. For example, single Litz wire or multiple strand windings108may be used in configuring either machine100, individual rotors102, rotors pairs160, or other desired sets of rotors102. The use of multiple windings108in a machine100can be used, as for example in conjunction with suitable mechanical indexing of the rotors102to fully or partially provide desired phasings in torque applied by rotors102to shaft or load104. For example, 3-phase windings used in known electric machines may be formed by appropriate interconnections of the separate windings in machines100according to the present disclosure. As depicted, each rotor-driven gear118engages the periphery of central gear120such that total torque applied to central gear120is the sum of the torques applied by the gears118. If winding(s)108are configured substantially circumferentially about axis200of shaft104and therefore machine100, an index angle112may be defined between equators (that is, the line dividing magnet128into north and south halves)202of individual magnets128and radii204extending from axis200to the corresponding rotor102. By suitable arrangement of rotors102and/or gears118, index angles112may be set at desired values for individual rotors, and sets thereof, with the result that phased torque output applied by each of the rotor pairs160can be applied to provide smooth, continuous torque to shaft104, when operated as a motor. When operated as a generator, smooth and continuous current may be output from overall winding(s)108. FIG.1depicts an embodiment having 12 rotors102(or6pairs160) and 6 phases. As will be understood, embodiments described herein can be adapted to 6-rotor, 3-phase systems, 24-rotor, 12-phase systems, and other combinations. In some embodiments, each rotor102ain a given pair160amay be phased magnetically at 180 degrees with respect to its pair mate102b. Further, each of the6pairs160a,160b,160c,160d,160e,160fmay be phased at 60 degrees relative to adjacent pairs. It should be appreciated that inFIG.2, for simplicity, reference numerals160a-frefer only to respective pairs of rotors102a,102b. Likewise, in a 6-rotor, 3-phase system, each adjacent rotor pair160a,160b,160ccan be indexed by 120 degrees with respect to adjacent pairs. The same logic may be applied to configurations with more or fewer rotors. However, in spite of providing smooth and continuous torque to central gear120as an overall system, each gear118in machine100suffers from a relatively high torque ripple (i.e., torques variations of a higher amplitude) during operation. That is, owing the nature of the operation of AC machines, the torque delivered by each rotor102varies from 0 to the maximum output torque twice per cycle. The impact of this torque ripple may be substantial in terms of the working life for a gear, as the gears are subjected to a wide variation of stress. The machine100may require low-backlash gears and/or high strength gears, which are expensive and may nevertheless be subjected to fretting damage over the course of operation. FIG.4is a simplified schematic perspective view of portions of an example embodiment of an electric machine system400having multiple rotors on a common shaft. As depicted, machine system400includes a plurality of multi-rotor machines410,410′,410″ located in different planes along the axial direction of shaft104. In some embodiments, as with machine100, the rotors depicted inFIG.4are magnetically indexed in pairs160of rotors102a,102bwhich share a common stator122. In some embodiments, rotors102aand102bmay be offset by 180 degrees. As depicted, in each machine in system400, each rotor pair160a,160b,160c,160d,160e,160fmay have a phase offset of 60 degrees relative to adjacent rotor pairs of the same machine. As depicted, the rotors102of machine410are disposed to define a circular array arrangement about axis200, and the rotors102′ of machine410′ are disposed to define a circular array arrangement about axis200which is axially offset from the circular array arrangement of machine410. In some embodiments, the circular array arrangement of machine410may be coaxial with the circular array arrangement of machine410′. In an example embodiment using 3-phase power, in first machine410, windings for rotor pairs160a,160dmay be supplied with current from a first phase (denoted as phase C). Windings for rotor pairs160b,160emay be supplied with current from a second phase (denoted as phase A). Windings for rotor pairs160c,160fmay be supplied with current from a third phase (denoted as phase B). In the example embodiment ofFIG.4, windings for each pair160a′,160b′,160c′,160d′,160e′,160f′ of rotors102a′,102b′ in second machine410′ are similarly supplied by one of 3 phases (phase A, phase B, or phase C). Relative to axis200, the current for the windings in second machine410′ are phase shifted by 120 degrees. As such, windings for pairs160a′ and160d′ are supplied by phase A, windings for pairs160b′ and160e′ are supplied by phase B, and windings for pairs160c′ and160f′ are supplied by phase C. Similarly, the current for the windings in third machine410″ is phase shifted by 240 degrees relative to first machine410. As such, windings for pairs160a″,160d″ are supplied by B, windings for pairs160b″,160e″ are supplied by phase C, and windings for pairs160c″,160f″ are supplied by phase A. As depicted, machine400includes one or more extended rotor shafts416awhich interconnect a given rotor102ain first machine410to a corresponding rotor102a′ in second machine410′ and a corresponding rotor102a″ in third machine410″. In some embodiments, shaft416ainterconnects a first rotor102aand a second rotor102a′ without interconnecting a third rotor102a″. As depicted, the rotors102a,102a′,102a″ are disposed at different axial positions relative to axis200of shaft104. In some embodiments, rotors102a,102a′,102a″ are coaxial. The total net torque delivered by rotor shaft416amay be the sum of the torque provided by rotors102a,102a′,102a″. Moreover, it will be appreciated that each of rotors102a,102a′,102a″ is coupled to one of phase A, phase B, and phase C, respectively. As such, the resulting net torque provided to shaft416awould be the sum of torques provided by rotors which are coupled to phases A, B and C, which are each offset by 120 degrees relative to the other phases. As such, the ripple in torque delivered by rotor shaft416amay be substantially reduced.FIG.5is a diagram depicting the torque delivered by a rotor shaft116of machine100.FIG.6is a diagram depicting the torque delivered by rotor shaft416aof machine system400. As will be appreciated, the torque delivered by rotor shaft416aexhibits substantially less torque ripple (i.e., torques variations of a lower amplitude) than machine100. Rotor shaft416brotatably connects rotor102bin first machine410to rotor102b′ in second machine410′ and to rotor102b″ in third machine410″ to define collective rotor450b. Again, rotor shaft416bis provided with torque from 3 rotors which are coupled to three separate phases A, B and C. As such, the torque delivered by collective rotor450bexhibits substantially less torque ripple than machine100. In some embodiments, rotors102a,102bin machine410are mechanically 180 degrees out of phase, rotors102a′,102b′ in machine410′ are mechanically 180 degrees out of phase, and rotors102a″,102b″ in machine410″ are mechanically 180 degrees out of phase with one another. This may further enhance the efficiency of machine system400. It should be appreciated that for simplicity, only two extended rotor shafts416a,416bare illustrated inFIG.4. In some embodiments there may be a corresponding extended rotor shaft416for each rotor in first machine410, provided there is a corresponding rotor in at least a second machine410′ to which the extended rotor shaft416can be connected. In some embodiments, the number of extended rotor shafts416may be less than the number of rotors in a given plane. In some embodiments, the extended rotor shafts416may have parallel rotational axes. AlthoughFIG.4depicts an electric machine system400with 3 parallel machines410,410′,410″, it will be appreciated that embodiments with more than 3 or fewer than 3 parallel machines410are also contemplated. Similar configurations can be implemented using the appropriate phase differences between magnetic cores in different planes. In embodiments with two machines410,410′, the first rotor102a, second rotor102a′ and shaft416aare coupled for common rotation. In some embodiments, each rotor shaft416has a gear118affixed or connected thereto. As depicted, gear118is affixed or otherwise attached to rotor shaft416such that rotation of rotor shaft416causes gear118to rotate along the same rotational axis as the rotor shaft416. Gear118is configured to engage with central gear120to drive a load. Given that the torque ripple is substantially reduced for each gear118owing to the rotor shaft416shared across machines410,410′,410″, it will be appreciated that some embodiments disclosed herein may reduce the amplitude of the cyclic stress experienced by gears118while engaging with central gear120. This may in turn increase the working life of gears, and may allow for the use of less expensive materials for gears118. The reduction in the likelihood that gears118will suffer damage during operation may further increase the reliability and dependability of machine400relative to known electric machines. FIG.7is a simplified front cut-away view of the machine100depicted inFIG.2. As depicted, a common stator122is provided for each pair160of rotors102a,102b. Each stator122has a winding108, although it will be appreciated that in some embodiments, a stator has more than one winding108. In addition, windings for pairs160aand160dreceive current from phase A, windings for pairs160band160ereceive current from phase B, and windings for pairs160cand160freceive current from phase C. It should be appreciated that any two stators can be connected by a single phase. In some embodiments, phase B is offset by 120 degrees from phase A, and phase C is offset by 240 degrees from phase A. The machine100may suffer from considerable losses during operation, and uses substantial quantities of iron, which implies greater weight and cost. Moreover, the configuration depicted inFIG.7may require a number of rotors which is divisible by 3. Since the rotors102a,102bare provided in pairs, this may limit the possible configurations to those which include 6 rotors, 12 rotors, 18 rotors, or the like. It may be desirable to have greater flexibility in the number of rotors which can be included in a multi-rotor electric machine. Moreover, it may be desirable to reduce the quantity of iron required for stators and therefore the weight, cost, and losses associated with machine100. FIG.8is a simplified front cut-away view of an electric machine system800. As depicted, machine800includes a first multi-rotor machine810located in a first plane. Machine810includes one stator822and a plurality of windings808(depicted as winding808abfor the winding appearing between rotors802aand802b, and so forth) and rotors802a,802b,802c,802d, . . . ,802n. It should be appreciated that machine810can have any number of rotors802. That is, the number of rotors802need not be in multiples of 3, and the rotors need not be indexed in magnetically independent pairs as with machine100, so there need not be an even number of rotors802. In some embodiments, there is one common stator822for all rotors802a,802b,802c,802d, . . . ,802nin machine810, and the electric power is supplied by a single phase (e.g. phase A). In some embodiments, the electric power is supplied in the form of AC electric power and the machine810operates as an asynchronous machine. In some embodiments, the electric power may be supplied as DC current, and machine810may operate as a DC motor. In some embodiments, rotors802a,802b,802c,802d, . . . ,802nare disposed in a circular array arrangement circumferentially around axis200of central shaft104. An index angle may be defined between equators (i.e. the line dividing north and south poles) for individual magnets for each rotor802and radii904extending from axis200to the corresponding rotor802. For simplicity, only radii904c,904dare depicted for corresponding rotors802c,802dand index angles for other rotors802are omitted. As depicted, rotors802cand802dhave index angles of 0 degrees, because the equator is parallel to radii904c,904d, respectively. By suitable positional phase offset of rotors802and/or rotor gears818, index angles may be set at desired values for individual rotors, with the result that torque output applied by each rotor802can be enhanced. The configuration of machine810inFIG.8may substantially reduce the amount of iron (e.g. for laminations) required, which may in turn reduce the weight, associated costs, and losses inside machine810during operation. In some embodiments, the configuration depicted inFIG.8may require 40% less iron to produce similar output power relative to machine100. It will be appreciated that during operation, the output torque of each rotor802in machine810may exhibit a large degree of torque ripple, as each rotor802a,802b, . . .802nvaries between delivering no torque and the maximum output torque. FIG.9is a side view of electric machine system800illustrating multiple machines810,810′,810″ in parallel on different planes. As depicted, machine800includes first machine810in a first plane, second machine810′ in a second plane, and third machine810″ in a third plane. The machines810,810′,810″ are positioned substantially perpendicularly to axis200of shaft104. In some embodiments, machines810,810′,810″ are substantially parallel to one another. In some embodiments, the circular array arrangement of rotors of machine810may be coaxial with the circular array arrangement of rotors of machine810′. In some embodiments, the circular array arrangement of rotors of machine810may be axially offset from the second array arrangement of rotors of machine810′. Rotor shafts816(e.g. rotor shaft816d) interconnect a respective rotor in machine810(e.g. rotor802d) to a respective rotor in machine810′ (e.g. rotor802d′) and to a respective rotor in machine810″ (e.g. rotor802d″). As depicted, respective gears818are connected or affixed to rotor shafts816. As depicted, gear818is affixed or otherwise attached to rotor shaft816in a manner such that rotation of rotor shaft816causes gear818to rotate in the same direction and with a common rotational axis to shaft816. In some embodiments, rotor shaft816dis drivingly coupled to shaft104or a load via gear818d. As referenced herein, the expression “drivingly coupled” encompasses an arrangement in which the rotation of one element results in the rotation or movement of another element (e.g., directly or indirectly). For example, although rotor shaft816ddoes not directly touch shaft104, the rotation of rotor shaft816dcauses gear818dto rotate, which engages the central gear120and causes shaft104to rotate. For simplicity,FIG.9depicts gear818ccoupled to rotor shaft816cand gear818dcoupled to rotor shaft816d. Reference numerals for other gears and rotor shafts have been omitted for simplicity. As depicted, rotors shafts816c,816dmay have parallel rotational axes. In some embodiments, an additional gear818c′ may be connected to rotor shaft816c. The use of additional gear818c′ may further reduce the stress and strain experienced by gears during operation, as the stress and strain is distributed between two gears818c,818c′ rather than concentrated on a single gear. Example embodiments which incorporate more than one gear are described in further detail below with reference toFIG.12. In some embodiments, the windings808of first machine810may be supplied with electric power from a first single phase (phase A). In some embodiments, the windings108′ of second machine810′ may be supplied with electric power from a second single phase (phase B). In some embodiments, the windings108″ of third machine810″ may be supplied with electric power from a third single phase (phase C). Phase B may be offset from phase A by 120 degrees. Phase C may be offset from phase A by 240 degrees. As noted above, each machine810,810′,810″ includes a single common stator822,822′,822″, respectively, and as such each machine810,810′,810″ is powered by a unique phase. The output torque from each rotor shaft (e.g.816d) is equal to the sum of torques output by individual rotors (e.g.802d,802d′,802d″). If phase B is offset from phase A by 120 degrees, and phase C is offset from phase A by 240 degrees, the net output torque provided by rotor shaft816dmay have substantially less torque ripple relative to the output torque of any individual machine810,810′ or810″. The output torque waveform may be similar in nature to that ofFIG.6(although the quantitative torque output might not be similar between machines400and800). For example, if the output torque of rotor802dvaries between 0 and the maximum output torque, then the sum of the output torque of rotor802dwith rotors802d′ and802d″ (which are offset by 120 degrees) would result in a far more stable output torque with less torque ripple than a single rotor. Machine system800may also provide additional versatility and flexibility relative to other electric machines. For example, the same magnetic circuit can be used for both high-input speed generators, as well as low output speed propulsion motors by selecting the appropriate ratio between the gears818and the central gear120. The speed selection may be carried out without the addition of a separate gearbox, which avoids the costs and weight associated with a gearbox as would be required by other electric machines. Moreover, the machine800may allow for the use of the same bi-pole rotors802in machines of different sizes, because any suitable number of rotors802can be used to obtain the desired output torque. As such, cost savings may be achieved by using the same standardized rotors802across different applications, rather than having to tailor rotors802depending on the specific intended use of the machine800. In addition, in machine800, winding coils are exposed and the magnetic rotors802are distributed around the machine assembly, which may facilitate heat extraction from the machine800in a more convenient manner relative to machines where copper windings are contained within the stator iron. This may help to increase the power per weight and power per volume ratios of machine800relative to other electric machines. FIG.10Ais a simplified schematic side cross-sectional view of an individual rotor shaft816dof machine800. As depicted, each rotor shaft816interconnects rotors802d,802d′,802d″ to gears818d,818d′.FIG.10Bis a view of rotor802don axis A-A inFIG.10A. As depicted, rotor802dincludes a magnet with north and south poles and an equator.FIG.10Cis a view of rotor802d′ on axis B-B inFIG.10A. As depicted, rotor802d′ includes a magnet with north and south poles, and is mechanically indexed by 120 degrees relative to rotor802d.FIG.10Dis a view of rotor802d″ on axis C-C inFIG.10A. As depicted, rotor802d″ includes a magnet with north and south poles, and is mechanically indexed by 240 degrees relative to rotor802d, and by 120 degrees relative to rotor802d′. It should be appreciated that althoughFIGS.10A-10Dillustrate a particular configuration of rotor indexing in machine800, it is contemplated that other configurations may be used in order to enhance the operational characteristics of machine system800. In some embodiments, each rotor802in first machine810is connected to a respective rotor802′ in second machine810′ and a respective rotor802″ in third machine810″ via a rotor shaft816. In some embodiments, there may be fewer rotor shafts816than there are rotors in machine810. FIG.11depicts an alternative configuration of an electric machine system1100. Machine system1100is similar to machine system800in that each machine1110,1110′,1110″ contains a plurality of rotors and a single stator and phase for each machine. Machine system1100differs in that one winding1108is provided between every pair of rotors. For example, referring toFIG.8, winding808abmay be provided between rotors802aand802b, and winding808cdmay be provided between rotors802cand802d. However, every second winding (e.g. windings808bc,808de,808fg,808hi,808jk,808lm) is omitted. Removing every second winding and rotating the middle machine1110′ may allow for the interlaced configuration depicted inFIG.11. As shown, the windings of each adjacent machine1110,1110′,1110″ are offset in such a manner that windings of adjacent machines cannot touch. This may provide an added benefit of reducing the possibility of phase-to-phase short circuits, which may occur if windings from adjacent machines are too closely packed together. As an additional advantage, the configuration ofFIG.11may save axial space, which may be advantageous in applications in which space is limited or at a premium. It should be appreciated that althoughFIG.9depicts an embodiment of machine system800with machines810in 3 planes, it is contemplated that some embodiments may include fewer than 3 machines810in parallel, and some embodiments may include more than 3 machines810in parallel, connected via rotor shafts816to define common rotors between machines. As noted above, in some embodiments, machine systems400,800,1100may include more than one gear418,818coupled to an individual rotor shaft416,816.FIG.12is a partial cross-sectional view of an electric machine system1200with multiple gears affixed or connected to each rotor shaft816. It should be noted that although machine1200is described with reference to machine800, the principles disclosed herein relating to machine1200with multiple gears per rotor shaft may be applied to numerous electric machine systems (and in particular to machine system400described herein). As shown inFIG.12, rotor shaft816dinterconnects each of rotors802d,802d′,802d″. Gear818dis connected to rotor shaft816dadjacent to rotor802d, and driving gear818d′ is connected to rotor shaft816dadjacent to rotor808d″. Each of gears818d,818d′ is configured to engage with central gears. As depicted, driving gear818dengages with a first central gear120, and driving gear818d′ engages with a second central gear120′. Each of central gears120,120′ are rotatably fixed to shaft104. As such, when rotor shaft816dis caused to rotate by rotors802d,802d′,802d″, both of gears818dand818d′ are caused to drive central gears120and120′, respectively. Thus, the net torque applied to central shaft104is the sum of the torque applied by gears818dand818d′. It will be appreciated that relative to configurations with only one gear818dper rotor shaft816d, roughly the same net torque will be produced by the rotors802d,802d′,802d″. As such, if gears818d,818d′ have the same dimensions and central gears120,120′ have the same dimensions, the torque exerted by each gear818d,818d′ would be expected to be roughly half of the torque applied by gear818din an embodiment with one gear (minus any additional losses caused by the extra weight of the additional gear, and the like). Therefore, the addition of second gear818d′ may result in the strain and stress on each gear818d,818d′ being significantly reduced, which may allow for the use of less expensive materials which are less resistant to stress (e.g. plastic), and may require less ongoing maintenance (e.g. less oil). AlthoughFIG.12depicts two gears818d,818d′ per collective rotor, it should be appreciated that other embodiments which involve more than two gears (e.g. additional central gears and additional gears818dwhich are located between any of rotors802d,802d′,802d″) are contemplated, and may further reduce the stress and strain experience by gears. It should be further noted that althoughFIG.12depicts an embodiment in which both central gears120and120′ are fixed to the same central shaft104, it is contemplated that in other embodiments, central gear120may be fixed to a first input/output shaft1304, and central gear120′ may be fixed to a second input/output shaft1304′ which may rotate independently from first input/output shaft1304. As such, some embodiments of machine1200may be suitable for use in gearbox applications, without requiring the addition of a gearbox to machine1200, which may provide numerous benefits relating to lower costs and reducing the weight and amounts of materials required for a given application. FIG.13is a schematic partial cross-sectional view of an electric machine1300system having an independent input shaft1304and output shaft1304′. Machine system1300is similar to machine system1200in many respects. Machine system1300includes one or more collective rotors1350(for simplicity, only one collective rotor1350is shown). Rotor shaft1316interconnects rotors1302,1302′,1302″ of machines1310,1310′,1310″ to define collective rotor1350, and input gear1318is fixed to an end of collective rotor1350adjacent to first rotor1302. Output gear1318′ is fixed to another end of collective rotor1350adjacent to third rotor1302″. In some embodiments, collective rotors1350have parallel rotational axes. In some embodiments, the collective rotors1350may be disposed to define a circular array arrangement. AlthoughFIG.13depicts machine1300having 3 rotors per collective rotor, it will be appreciated that embodiments with as few as one electric machine rotor per collective rotor1350are contemplated. Embodiments with more than 3 electric machine rotors per collective rotor1350are also contemplated. In some embodiments, the electric machine rotors are axially spaced apart between the input gear1318and output gear1318′. As depicted, input gear1318is drivingly coupled to input shaft1304via first central gear1320. First central gear may be fixed to input shaft1304. Output gear1318′ is drivingly coupled to output shaft1304′ via second central gear1320′. Second central gear1320′ is coupled to output shaft1304′. In some embodiments, input shaft1304is connected to a gas turbine. In some embodiments, output shaft1304′ is connected to a propeller or fan. It will be appreciated that the speed at which input shaft rotates may be substantially different (faster or slower) from the speed at which output shaft rotates. Normally, a separate gearbox may be used to transfer mechanical energy from one rotating gear to another. However, in the embodiment shown inFIG.13, no separate gearbox is required. Instead, the sizes of first central gear1320, input gear1318, output gear1318′ and second central gear1320′ may be chosen such that the gear ratios allow for a rotation at the input shaft1304to result in a rotation in or around a desired speed at output shaft1304′. Such rotation is achieved by the rotation of input shaft1304causing first central gear1320to rotate. The rotation of first central gear1320causes input gear1318to rotate at an angular speed. Output gear1318′ shares rotor shaft1316with input gear1318, and so the output gear1318′ will also rotate at the same angular speed as input gear1318. Output gear1318′ is coupled to second central gear1320′, and so the rotation of output gear1318′ causes the rotation of second central gear1320′, thereby causing the resulting rotation of output shaft1304′. In some embodiments, electrical rotors1302,1302′,1302″ in machine system1300are operable in a generating mode and in a motoring mode. When electrical rotors1302,1302′,1302″ are operating in a motoring mode, the rotor shafts1316may be indexed to provide a torque phase offset relative to each other. When electrically powered, the mechanical power at the input shaft1304is transmitted through machine1300in a manner similar to that of a gearbox. When electrical rotors1302,1302′,1302″ are electrically powered, the power output to output shaft1304′ is the sum of the mechanical power at input shaft1304and the output power of machines1310,1310′,1310″. As such, in situations where the mechanical input power at shaft1304is insufficient to achieve the desired output at output shaft1304′, machines1310,1310′,1310″ may be electrically powered so as to provide additional output power to output shaft1304′. In addition, the machine system1300can act as an in-line generator to convert some of the mechanical input power at shaft1304to electrical current at windings1308,1308′,1308″. This electrical power may be used for various purposes, such as, for example, aircraft electrical systems, charging batteries, or the like. In some embodiments (e.g. turbine engines), the generated electrical power may be used to accelerate or apply positive torque to the high pressure spool or compressor spool of an engine core. Contrary to conventional hybrid electrical applications, the assistance provided by machine1300is not applied on a high-speed output shaft or to an auxiliary pad of a reduction gearbox. Instead, machine1300may act as a gearbox with an electric machine embedded therein. Of course, the above described embodiments are intended to be illustrative only and in no way limiting. The described embodiments are susceptible to many modifications of form, arrangement of parts, details and order of operation. The invention is intended to encompass all such modification within its scope, as defined by the claims. | 34,357 |
11863033 | DETAILED DESCRIPTION OF THE EMBODIMENTS To make the objects, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below. Apparently, the described embodiments are merely some but not all of the embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skills in the art without going through any creative work shall fall within the scope of protection of the present disclosure. FIG.1is a schematic structural diagram of a displacement detection circuit of a maglev rotor system provided by an embodiment of the present disclosure. As shown inFIG.1, the displacement detection circuit of the maglev rotor system may include a current sampling circuit10, Hall sensors20, a Hall signal processing circuit30, and a displacement signal resolving circuit40. The Hall signal processing circuit30is connected to the Hall sensors20. The displacement signal resolving circuit40is connected to the current sampling circuit10and the Hall signal processing circuit30, respectively. FIG.2is a schematic structural diagram of a top view of the maglev rotor system provided by the embodiment of the present disclosure along an axial direction. Referring toFIGS.1and2, the current sampling circuit10is configured to collect a current flowing through coils4, wherein coils4include coils distributed in series in the maglev rotor system. The maglev rotor system may be a permanent-magnet offset maglev rotor system with an auxiliary air gap8, and the maglev rotor system is a two-degree-of-freedom bearing, which may be configured to support in X and Y directions at the same time.FIG.1shows a cross-sectional view of the maglev rotor system along the axial direction. Taking the X direction as an example, among four coils4shown inFIG.1which are distributed in series in the same direction in the permanent-magnet offset maglev rotor system, two coils4distributed in an X+ direction are connected in series in the same direction, two coils4distributed in an X− direction are connected in series in the same direction, and the coils4of X+ and X− are connected in series in opposite directions. Currents flowing through the four coils4are equal, such that it is only necessary to sample the current flowing through one coil4in the same direction. Specifically, with reference toFIGS.1and2, the maglev rotor system includes two outer magnetic conducting bodies (namely stator magnetic conducting rings1and one permanent magnet2), eight stator cores3, eight exciting coils4, one inner magnetic conducting ring (namely a rotator magnetic conducting body5), two rotor cores6and eight outer magnetic isolating bodies9. The eight stator cores3form stator magnetic poles in the X and Y directions at left and right ends of the maglev rotor system, wherein every four stator cores3form four stator magnetic poles in the X and Y directions at one end of the maglev rotor system. The eight outer magnetic isolating bodies9are connected to the stator cores3in the X and Y directions at the left and right ends of the maglev rotor system, each stator magnetic pole is wound with the exciting coil4, and the outer magnetic conducting bodies1are arranged outside the stator cores3. The permanent magnet2is located between the two outer magnetic conducting bodies1in the axial direction, an auxiliary air gap8is formed inside the permanent magnet2between the two outer magnetic conducting bodies1in the axial direction, and the auxiliary air gap8is configured to form an electrically excited flux path. The rotor cores6are arranged inside the stator cores3, and a certain gap is left between inner surfaces of the stator cores3and outer surfaces of the rotor cores6to form an air gap7, which is namely a primary air gap7. The inner magnetic conducting ring5is mounted inside the rotor cores6and connects the rotor cores6at the left and right ends to form a flux path. The Hall sensors20are arranged in an upper auxiliary air gap and a lower auxiliary air gap of the maglev rotor system. The sensing surfaces of the Hall sensors are perpendicular to magnetic field directions in the corresponding auxiliary air gaps8. As illustrated inFIG.1andFIG.2, the Hall sensors20may be miniature flexible probes with a thickness less than 0.5 mm. The sensing surfaces of the Hall sensors20are arranged perpendicular to the magnetic field directions in the corresponding auxiliary air gaps8, such that the detection by the Hall sensors20and the control by the maglev rotor system are coplanar. FIG.3is a schematic structural diagram of a cross section of the maglev rotor system provided by the embodiment of the present disclosure along the axial direction. Referring toFIGS.1-3, the Hall signal processing circuit30is connected to the Hall sensors20, and the Hall signal processing circuit30is configured to perform differential processing a Hall sensing signal corresponding to the upper auxiliary air gap and a Hall sensing signal corresponding to the lower auxiliary air gap. Specifically, referring toFIGS.1-3, in the maglev rotor system, an electromagnetic path is a magnetic path shown by a dotted line inFIG.3, and the electromagnetic path must pass through the auxiliary air gaps8in addition to passing through the primary air gap7to form a closed loop. A permanent magnetic path is a magnetic path shown by a solid line inFIG.3. The permanent magnetic path is divided into two parts, wherein one part of the permanent magnetic path passes through the primary air gap7and the other part of the permanent magnetic path passes through the auxiliary air gap8. Therefore, a magnetic field in the auxiliary air gap8is formed by superposing an electromagnetic field with a part of permanent magnetic field. Influenced by a control current and a length of the primary air gap, an electromagnetic flux in the auxiliary air gap8is a variable value, while a magnetic resistance of the auxiliary air gap8is constant, and a permanent magnetic flux in the auxiliary air gap8is a fixed value. In the embodiment of the present disclosure, the Hall signal processing circuit30is arranged to differentiate the Hall sensing signal corresponding to the upper auxiliary air gap from the Hall sensing signal corresponding to the lower auxiliary air gap, such that an influence of the permanent magnetic flux in the auxiliary air gap8may be counteracted to obtain a quantity only related to the electromagnetic flux. The displacement signal resolving circuit40is connected to the current sampling circuit10and the Hall signal processing circuit30, respectively. The displacement signal resolving circuit40is configured to acquire a displacement of a rotor in the maglev rotor system according to the current and a result of the differential processing, which means that the displacement signal resolving circuit40can directly obtain a width of the primary air gap corresponding to the displacement of the rotor to be acquired in the maglev rotor system according to the current flowing through the corresponding coil4collected by the current sampling circuit10and the result of the differential processing of the Hall sensing signal corresponding to the upper auxiliary air gap and the Hall sensing signal corresponding to the lower auxiliary air gap by the Hall signal processing circuit30, thus acquiring a position of the rotor in the maglev rotor system. Therefore, all functions of a traditional position sensor and a traditional position self-sensing detection method are realized, and meanwhile, there are advantages that an axial size of the rotor is reduced, the detection and the control are coplanar, and high precision and simple design are realized, thus providing conditions for high-precision control by the maglev system. FIG.4is a schematic structural diagram of the current sampling circuit provided by the embodiment of the present disclosure. Referring toFIGS.1-4, the current sampling circuit10comprises a first amplifying circuit U2B, wherein the first amplifying circuit U2B is configured to amplify the current flowing through a sampling resistor. Specifically, it is only necessary to sample the current flowing through one coil4in the same direction, which means that only one sampling resistor R is needed in the same direction. One end of the sampling resistor R may be connected to one external terminal A of the four coils4, and the other end of the sampling resistor R may be connected to the other external terminals B of the four coils4. Currents flowing through the four coils4may be obtained by collecting the current flowing through the sampling resistor R. Illustratively, the sampling resistor R may be connected in series with a power amplifier50to preliminarily amplify the current collected by the current sampling circuit10, thus improving a current detection precision. The first amplifying circuit U2B is configured to amplify the current flowing through the sampling resistor R, and the current sampling circuit10may calculate an output current of the corresponding coil4by detecting voltages at the positive and negative ends of the sampling resistor R. Illustratively, as shown inFIG.4, the current sampling circuit10may further comprise a first voltage following circuit U2A and a first filter circuit U2C. A forward end + and a reverse end − of a current detection amplifier Ul are connected to two ends of the sampling resistor R, respectively. By detecting voltages at the positive and negative ends of the sampling resistor R, the current flowing through the output coil4is calculated. The current enters the first amplifying circuit U2B through the first voltage following circuit U2A, the first amplifying circuit U2B amplifies the current by a set number of times, and then the amplified current is filtered by the first filter circuit U2C and outputted. In this way, the current sampling circuit10has fewer stages, is easy to realize, and can effectively ensure the reliability of the system. Optionally, referring toFIGS.1-4, the width of the primary air gap corresponding to the displacement of the rotor to be acquired may be set to satisfy the following calculation formula: h=12A2(2A2h1+A1h2)2-2μ0NI(4A2h1+2A1h2)B1-B2,wherein h is the width of the primary air gap corresponding to the displacement of the rotor to be acquired; the displacement of the rotor in the maglev rotor system is equal to a sum of the position of the stator in the maglev rotor system and the width of the primary air gap corresponding to the displacement of the rotor; μ0is a permeability of vacuum; N is a number of turns of one of the coils; and I is the current flowing through the coil4. When the rotor in the maglev rotor system is located in a balanced position, the primary air gap has a width of h1and a surface area of A1. The auxiliary air gap has a width of h2which is a constant and a surface area of A2. B1is the Hall sensing signal corresponding to the upper auxiliary air gap, and B2is the Hall sensing signal corresponding to the lower auxiliary air gap. Specifically, the above formula may be derived as follows. When the rotor in the maglev rotor system is located in the balanced position, the width of the primary air gap is set as h1and the surface area of the primary air gap is set as A1. The width of the auxiliary air gap is set as h2and the surface area of the auxiliary air gap is set as A2. The width of the primary air gap corresponding to the displacement of the rotor to be acquired is set as h. According to the Ampere's circuital law: Φ×(2R1+R2)=2NI,wherein Φ is a magnetic flux; N is the number of turns of an electromagnetic coil in the maglev rotor system, namely, a number of turns of one of the coil. I is the current of the coil, namely, the current flowing through the sampling resistor. R1is a magnetic resistance corresponding to the primary air gap. R2is a magnetic resistance corresponding to the auxiliary air gap. R1satisfies the following calculation formula: R1=h1+hμ0A1, R2satisfies the following formula: R2=h2μ0A2. A magnetic induction intensity Bc1generated by an electromagnetic flux in the upper auxiliary air gap is: Be1=ΦA2=2μ0NI2A2(h1+h)+A1h2. A magnetic induction intensity Bc2generated by an electromagnetic flux in the lower auxiliary air gap is: Be2=ΦA2=-2μ0NI2A2(h1-h)+A1h2. A magnetic field in the auxiliary air gap is formed by superposing an electromagnetic field with a part of a permanent magnetic field, and considering an influence of a permanent magnetic flux BY, a magnetic induction intensity B1generated by a magnetic field in the upper auxiliary air gap satisfies the following calculation formula: B1=Be1+By=2μ0NI2A2(h1+h)+A1h2+By. A magnetic induction intensity B2generated by a magnetic field in the lower auxiliary air gap satisfies the following formula: B2=Be2+By=-2μ0NI2A2(h1-h)+A1h2+By. In order to eliminate a common-mode interference, the magnetic induction intensity B1generated by the magnetic field in the upper auxiliary air gap and the magnetic induction intensity B2generated by the magnetic field in the lower auxiliary air gap are differentiated to obtained that: B1-B2=2μ0NI2A2(h1+h)+A1h2--2μ0NI2A2(h1-h)+A1h2=2μ0NI*4A2h1+2A1h2(2A2h1+A1h2)2-4A22h2. According to an inverse solution, the width h of the primary air gap corresponding to the displacement of the rotor to be acquired satisfies the following calculation formula: h=12A2(2A2h1+A1h2)2-2μ0NI(4A2h1+2A1h2)Bupper-Blower. The displacement of the rotor in the maglev rotor system is equal to a position of a stator in the maglev rotor system, which is namely a sum of a position of a bearing and the width h of the primary air gap corresponding to the displacement of the rotor, thus acquiring the displacement of the rotor in the maglev rotor system. Optionally, an amplification factor of the first amplifying circuit U2B may be set based on the following formula: a=2μ0N(4A2h1+2A1h2),wherein a is the amplification factor of the first amplifying circuit U2B; μ0is the permeability of vacuum; and N is the number of turns of one of the coils. When the rotor in the maglev rotor system is located in a balanced position, the primary air gap has a width of h1and a surface area of A1, and the auxiliary air gap has a width of h2and a surface area of A2. The amplification factor a of the first amplifying circuit U2B is set to satisfy the above formula to obtain 2μ0NI(4A2h1+2A1h2) in the calculation formula of h, and I is the current flowing through the sampling resistor. FIG.5is a schematic structural diagram of the Hall signal processing circuit provided by the embodiment of the present disclosure. With reference toFIG.1toFIG.5, the Hall signal processing circuit30comprises two amplifying branches and a differential circuit U4D. One amplifying branch is a branch where R8is located, the other amplifying branch is a branch where R15is located, and the amplifying branches are connected to the corresponding Hall sensors20. Each amplifying branch comprises a second amplifying circuit. The amplifying branch where R8is located comprises a second amplifying circuit U3B, and the amplifying branch where R13is located comprises a second amplification circuit U4B. The second amplifying circuits in the amplifying branches are connected to the corresponding Hall sensing signals of the corresponding auxiliary air gaps, and output ends of the second amplifying circuits in the two amplifying branches are both connected to the differential circuit U4D. Specifically, one amplifying branch may be connected to the Hall sensor20corresponding to the upper auxiliary air gap, and the other amplifying branch may be connected to the Hall sensor20corresponding to the lower auxiliary air gap. For example, the amplifying branch comprising the resistor R8may be connected to the Hall sensor20corresponding to the upper auxiliary air gap, and the amplifying branch comprising the resistor R15may be connected to the Hall sensor20corresponding to the lower auxiliary air gap. The Hall sensors20transmit sensed signals of the corresponding auxiliary air gaps to the corresponding amplifying branches respectively, and the second amplifying circuits amplify corresponding currents by a set number of times and then output the amplified currents to the differential circuit U4D. Illustratively, a magnetic induction intensity B (a sum of an electromagnetic induction intensity and a permanent magnetic induction intensity) is detected based on a Hall effect. A Hall voltage U H=KHIHB is obtained through the Hall sensors, wherein KHis a Hall sensitivity, which is related to a material property and a geometric dimension of a Hall sheet, and is a constant for a certain Hall probe; and IHis a supply current to the probe, which is unrelated to the current of the coil. Therefore, it is obtained that: B=UHKHIH,wherein B is the magnetic induction intensity B of the corresponding air gap. Therefore, the amplification factor of the second amplifying circuit may be set as: 1KHIH,wherein IHis the supply current to the probe in the corresponding auxiliary air gap. Illustratively, as shown inFIG.5, each amplifying branch may further comprise a second voltage following circuit and a second filter circuit. The amplifying branch where R8is located comprises a second voltage following circuit U3A and a second filter circuit U3C, and the amplifying branch where R13is located comprises a second voltage following circuit U4A and a second filter circuit U4C. The Hall sensors20detect and output the currents in the auxiliary air gaps8, and the currents pass through the corresponding second voltage following circuits, second amplifiers and the second filter circuits and then are converted into magnetic induction intensities in the auxiliary air gaps8. The two magnetic induction intensities pass through the differential circuit U4D and then are outputted, which means that the differential circuit U4D realizes subtraction of B1and B2for eliminating a common-mode interference caused by a part of permanent magnetic flux in the auxiliary air gaps8to obtain a magnetic induction intensity difference only related to the electromagnetic coil. Optionally, the displacement signal resolving circuit40may comprise a division circuit and a square rooting circuit. The division circuit is connected to the square rooting circuit, the division circuit is configured to divide an output signal of the current sampling circuit10and an output signal of the Hall signal processing circuit30, and the square rooting circuit is configured for performing offset adjustment and square rooting functions on an output signal of the division circuit. FIG.6is a schematic structural diagram of the division circuit provided by the embodiment of the present disclosure. Referring toFIGS.1-6, the division circuit may comprise a main arithmetical unit U5. For example, U5may be a chip of model AD633AN. The output signal of the current sampling circuit10is inputted from a terminal IN2, and the output signal of the Hall signal processing circuit30is inputted from a terminal IN1, which means that a right end of R7is connected to the terminal IN2, and a right end of R23is connected to the terminal IN1, such that a division result is obtained at a terminal OUT of the division circuit. The result is as follows: -2μ0NI(4A2h1+2A1h2)Bupper-Blower This result is a negative number. FIG.7is a schematic structural diagram of the square rooting circuit provided by the embodiment of the present disclosure. With reference toFIG.1toFIG.7, the square rooting circuit may comprise an offset adjustment circuit and a square-rooting circuit U7A. U8B and U7C form the offset adjustment circuit. The offset adjustment circuit is connected to the square-rooting circuit, the offset adjustment circuit is configured to superimpose an offset adjustment value on the output signal of the division circuit according to a reference signal Vref, and the square-rooting circuit is configured to perform square rooting functions on an output signal of the offset adjustment circuit. Specifically, the square rooting circuit may further comprise a reference signal generating circuit, which is namely a circuit shown in the upper right ofFIG.7, and the reference voltage Vref is generated by TL431ACD and configured to perform offset adjustment. The square rooting circuit may further comprise a third voltage following circuit U7B and a third filter circuit U7D. The output signal of the division circuit is inputted from a left side of the resistor R31, after a calculation result of the division circuit passes through the third voltage following circuit U7B, the offset adjustment circuit, which is namely an offset modulator, superimposes a fixed value on the signal and then the signal is inversely outputted. The signal passes through the third filter circuit U7D and then is transmitted to the square-rooting circuit U7A, such as a negative voltage square-rooting processing circuit, for calculation, thus obtaining the width h of the primary air gap corresponding to the displacement of the rotor to be acquired. Optionally, the offset adjustment value corresponding to the offset adjustment circuit satisfies the following calculation formula: b=(2A2h1+A1h2)2,wherein b is the offset adjustment value corresponding to the offset adjustment circuit, and when the rotor in the maglev rotor system is located in a balanced position, the primary air gap has a width of h1and a surface area of A1, and the auxiliary air gap has a width of h2and a surface area of A2. With reference to the formula of h above, the calculation result of the division circuit is as follows: -2μ0NI(4A2h1+2A1h2)Bupper-Blower. (2A2h1+A1h2)2is superimposed on the calculation result and then the calculation result is inversely outputted. The calculation result passes through the third filter circuit U7D and then is calculated by the negative voltage square-rooting processing circuit, thus obtaining the width h of the primary air gap corresponding to the displacement of the rotor to be acquired. Optionally, referring toFIGS.1-7, amplification factor control resistors in the current sampling circuit10and the Hall signal processing circuit30, an amplification control resistor in the offset adjustment circuit and a reference signal introduction resistor are all sliding rheostats. The amplification factor control resistor in the current sampling circuit10is R3, the amplification factor control resistors in the Hall signal processing circuit30are R14and R21, the amplification factor control resistor in the offset adjustment circuit is R37, and the reference signal introduction resistor in the offset adjustment circuit is R39, which means that R3, R14, R21, R39, and R37may all be the sliding rheostats, such that the amplification factor satisfied by the amplifying circuit is reached by adjusting the amplification factor control resistor, and the offset adjustment value of the offset adjustment circuit is reached by adjusting the reference signal introduction resistor. Use of the sliding rheostats not only facilitates debugging, but also facilitates transplantation on different devices without modification, thus meeting a requirement of multiple sets of devices. In the embodiment of the present disclosure, the current of the coil in the sampling resistor may be obtained by the current sampling circuit10and is amplified and filtered. The Hall sensors20are placed in the auxiliary air gaps of the permanent-magnet offset maglev rotor system, and the sensing surfaces are perpendicular to the magnetic field directions. In this structure, a variable electromagnetic flux and a part of permanent magnetic flux pass through the auxiliary air gaps, and the part of permanent magnetic flux is a fixed value. The Hall sensors20sense the magnetic fields in the air gaps to obtain Hall voltages. After amplification and filtration by the Hall signal processing circuit30, a magnetic induction intensity of a unilateral air gap is obtained, and then magnetic induction intensities of bilateral air gaps are differentiated to eliminate the common-mode interference caused by the permanent magnetic flux in the auxiliary air gaps. The displacement signal resolving circuit40composed of a divider and an open circuit divides a filtered magnetic bearing coil current signal and a differentiated magnetic bearing air gap magnetic induction intensity first, and then a square-rooting operation is performed after offset adjustment to obtain a displacement signal. All functions of a traditional position sensor and a traditional position self-sensing detection method are realized, and meanwhile, there are advantages that the axial size of the rotor is reduced, the detection and the control are coplanar, and high precision and simple design are realized, thus providing conditions for high-precision control by the maglev system. The embodiment of the present disclosure further provides a maglev rotor displacement self-sensing system. As shown inFIG.1, the maglev rotor displacement self-sensing system comprises a maglev rotor system and the displacement detection circuit of the maglev rotor system in the embodiment above. The maglev rotor system is connected to the displacement detection circuit, and the maglev rotor system comprises a permanent magnet offset maglev rotor system with an auxiliary air gap. The maglev rotor displacement self-sensing system has the beneficial effects of the embodiment above, which will not be repeated herein. It should be noted that relational terms herein such as “first” and “second” and the like, are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply there is any such relationship or order between these entities or operations. Furthermore, the terms “including”, “comprising” or any variations thereof are intended to embrace a non-exclusive inclusion, such that a process, a method, an article, or a device including a series of elements, includes not only those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article, or device. In the absence of further limitation, an element defined by the phrase “including a . . . ” does not exclude the presence of the same element in the process, method, article, or device. The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or realize the present disclosure. Many modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not to be limited to these embodiments shown herein but is to be in conformity with the widest scope consistent with the principles and novel features disclosed herein. INDUSTRIAL APPLICABILITY The present disclosure is suitable for detecting the position of the rotor in the permanent magnet offset maglev rotor system with the auxiliary air gap, only the current value of the coil is needed, and the detection by the Hall sensors and the control by the maglev rotor system are coplanar. All functions of a traditional position sensor and a traditional position self-sensing detection method are realized, and meanwhile, there are advantages that the axial size of the rotor is reduced, the detection and the control are coplanar, and high precision and simple design are realized, thus providing conditions for high-precision control by the maglev system, with a very strong industrial practicability. | 27,988 |
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