Ground power supply equipment and wiring

Abstract

To suppress a resonance frequency from being differentiated in a plurality of coils.SOLUTION: A ground power feeding device 1 that contactlessly transmits electric power to a vehicle 5 comprises a plurality of resonance circuits 20, and one power supply source that supplies AC electric power of a same frequency to all of the resonance circuits. Each resonance circuit includes a coil 23 buried in a road for contactlessly transmitting electric power, and wiring 22 that connects each coil and the power supply source. The wiring of each resonance circuit has a length different at least in part from the wiring of other resonance circuits and is formed so that inductance parasitizing the wiring due to the difference in the length is different at least in part from the wiring of other resonance circuits. The resonance circuits further include a capacitor having different capacitance so that the resonance frequencies of all of the resonance circuits are equalized even when the inductance parasitizing the wiring is different.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to ground power feed devices and wiring. [Background technology]

[0002] A ground power supply device is known that has multiple coils for contactless power transmission and a single power source that supplies power to the coils, with the coils and the power source connected by conductors (JP 2019-526219 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-526219 Summary of the Invention [Problem to be solved by the invention]

[0004] The conductors connecting the power supply and the coil have different lengths because the distance between the power supply and the coil differs for each coil. Since the parasitic inductance of the conductor differs depending on the length of the conductor, the resonant frequency differs for each resonant circuit including conductors and coils of different lengths.

[0005] In view of the above-mentioned problems, an object of the present disclosure is to prevent the resonant frequencies from differing among multiple coils connected to one power source. [Means for solving the problem]

[0006] The gist of the present disclosure is as follows.

[0007] (1) A ground power supply device that transmits power to a vehicle in a non-contact manner, a plurality of resonant circuits; and a single power supply source that supplies AC power of the same frequency to all of the resonant circuits; Each resonant circuit has a coil embedded in the road for contactlessly transmitting power, and wiring connecting each coil to the power supply source, the wiring of each resonant circuit has a length at least partially different from the wiring of the other resonant circuits, and is formed so that the difference in length causes a parasitic inductance of the wiring to be at least partially different from the wiring of the other resonant circuits; The resonant circuits further include capacitors having different capacitances so that the resonant frequencies of all the resonant circuits are equal even if the parasitic inductances of the wiring are different. (2) The ground power supply device according to (1), wherein the capacitor has a capacitance such that the resonant frequencies of all resonant circuits are the same as the frequency of the AC power even if the parasitic inductances of the wiring are different. (3) The ground power supply device according to (1) or (2) above, wherein the wiring of the plurality of resonant circuits including the plurality of coils arranged adjacent to each other has the same length. (4) The wiring has a first portion having the same length in all the resonant circuits and a second portion having a length that varies partially between the resonant circuits, The ground power feeding device according to any one of (1) to (3) above, wherein the capacitor is provided in the second section. (5) The ground power feeding device according to (4), wherein the capacitors provided in the second portions having the same length have the same capacitance. (6) The ground power supply device according to (4) or (5) above, wherein the first section does not have a capacitor. (7) The ground power supply device according to any one of (4) to (6), wherein the first portion is connected to the coil, the second portion is connected to the power supply source, and a plurality of the second portions having the same length are connected to the first portion by the same connector. (8) The wiring is at least partially configured by connecting in series a plurality of wiring modules, each having a cable of the same length and a capacitor connected to the cable; the capacitor of each wiring module has a capacitance that cancels out the effect of parasitic inductance in the cable of the wiring module on the resonance frequency that occurs in the coil at the frequency of the AC power, The ground power supply device according to any one of (1) to (7), wherein the resonant circuits having wiring of different lengths have different lengths of wiring due to the number of the wiring modules constituting the wiring of the resonant circuits being different. (9) The ground power supply device according to (8), wherein the length of the cable of the wiring module is equal to an integer multiple of the distance between adjacent coils. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to prevent the resonant frequencies from differing among multiple coils connected to one power source. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram schematically showing a ground power feeding device and a vehicle according to the first embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating the configuration of a ground power feeding device and a vehicle according to the first embodiment. [Figure 3] FIG. 3 is a diagram schematically illustrating the configuration of a ground power feeding device according to the first embodiment. [Figure 4] FIG. 4 is a diagram similar to FIG. 3, which schematically shows the configuration of a ground power feeding device according to a modified example of the first embodiment. [Figure 5] FIG. 5 is a diagram similar to FIGS. 3 and 4, and schematically illustrates a configuration of a ground power feeding device according to a second embodiment. [Figure 6] FIG. 6 is a diagram similar to FIGS. 3 to 5, and schematically shows the configuration of a ground power feeding device according to a third embodiment. [Figure 7] FIG. 7 is a diagram schematically showing the configuration of each wiring module. [Figure 8] FIG. 8 is a diagram schematically showing the configuration of a ground power feeding device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the following description, like components are designated by like reference numerals.

[0011] First embodiment <Outline of Ground Power Supply Equipment> An overview of a ground power supply device 1 according to a first embodiment and a vehicle 5 that can receive power from the ground power supply device 1 will be described with reference to Fig. 1. Fig. 1 is a diagram that schematically shows the ground power supply device 1 and the vehicle 5 according to the first embodiment. The ground power supply device 1 transmits power to the vehicle 5 by contactless power transmission using magnetic field resonance coupling (magnetic field resonance). In particular, in this embodiment, contactless power transmission from the ground power supply device 1 to the vehicle 5 is performed while the vehicle 5 is traveling.

[0012] The term "in motion" refers to a state in which the vehicle 5 is positioned on a road for travel. Therefore, the term "in motion" includes not only a state in which the vehicle 5 is actually traveling at any speed greater than zero, but also a state in which the vehicle 5 is stopped on the road, for example, while waiting at a traffic light.

[0013] The ground power supply device 1 has a plurality of power transmission units 21 embedded in (underground) a road on which a vehicle 5 travels. As shown in Fig. 1 , in this embodiment, the power transmission units 21 are arranged at predetermined intervals along each lane 100, in the center of the lane 100 on which the vehicle 5 travels.

[0014] <Configuration of ground power supply equipment> Next, the configuration of the ground power feeding device 1 will be described briefly with reference to Fig. 2. Fig. 2 is a diagram showing the configuration of the ground power feeding device 1 and a vehicle 5. As shown in Fig. 2, the ground power feeding device 1 includes a power source 2, a power supply unit 10, a plurality of power transmitting side resonant circuits 20 including a power transmitting unit 21, and a controller 30. The power transmitting side resonant circuit 20 including the power transmitting unit 21 is embedded in the road (underground). Meanwhile, the power supply unit 10 and the controller 30 may be embedded in the road or may be located at a location separate from the road (including on the ground). In this embodiment, one power supply unit 10 is connected to a plurality of power transmitting side resonant circuits 20.

[0015] The power source 2 supplies power to the power transmission unit 21 via the power source unit 10. The power source 2 is, for example, a commercial AC power source that supplies single-phase AC power. Note that the power source 2 may be another AC power source that supplies three-phase AC power, or may be a DC power source such as a fuel cell.

[0016] The power supply unit 10 converts AC power supplied from the power supply 2 into high-frequency AC power to be supplied to the power transmission-side resonant circuit 20. The power supply unit 10 has a power transmission-side rectifier circuit 11 and an inverter 12. In the power supply unit 10, the AC power supplied from the power supply 2 is rectified in the power transmission-side rectifier circuit 11 and converted into DC current, and this DC current is converted into AC power in the inverter 12. The power supply 2 and the power supply unit 10 function as a power supply source that supplies AC power to the power transmission-side resonant circuit 20.

[0017] The power transmission side rectifier circuit 11 is electrically connected to the power source 2 and the inverter 12. The power transmission side rectifier circuit 11 rectifies AC power supplied from the power source 2 to convert it into DC power and supplies the DC power to the inverter 12. The power transmission side rectifier circuit 11 is, for example, an AC / DC converter. In this embodiment, one power transmission side rectifier circuit 11 is provided for one power supply unit 10. Note that if the power source 2 is a DC power supply, the power transmission side rectifier circuit 11 may be omitted.

[0018] The inverter 12 is electrically connected to the power transmitting side rectifier circuit 11 and the power transmitting side resonant circuit 20. The inverter 12 converts the DC power supplied from the power transmitting side rectifier circuit 11 into AC power (high frequency AC power) having a higher frequency than the AC power of the power supply 2, and supplies the high frequency AC power to the power transmitting side resonant circuit 20. In this embodiment, the power supply unit 10 has a number of inverters 12 corresponding to the number of power transmitting side resonant circuits 20. Each inverter 12 is connected to a corresponding one of the different power transmitting side resonant circuits 20. Furthermore, the inverters 12 supply AC power of the same frequency to the power transmitting side resonant circuits 20. Therefore, the power supply unit 10 supplies AC power of the same frequency to all of the power transmitting side resonant circuits 20.

[0019] The power transmitting side resonant circuit 20 has a power transmitting unit 21 and a wiring 22. The power transmitting side resonant circuit 20 is connected to the power supply unit 10, and generates an alternating magnetic field when high frequency AC power is supplied from the power supply unit 10.

[0020] The power transmitting unit 21 includes a power transmitting side coil 23 and a power transmitting side capacitor 24. When a current flows through the power transmitting side coil 23, the power transmitting side coil 23 generates a magnetic field for contactless power transmission. The power transmitting side coil 23 and the power transmitting side capacitor 24 form a resonator. Various parameters of the power transmitting side coil 23 and the power transmitting side capacitor 24 (such as the outer and inner diameters of the power transmitting side coil 23, the number of turns of the power transmitting side coil 23, and the capacitance of the power transmitting side capacitor 24) are determined so that the resonant frequency of the power transmitting unit 21 becomes a predetermined set value. The predetermined set value is, for example, 10 kHz to 100 GHz, and preferably 85 kHz, which is defined by the SAE TIR J2954 standard as the frequency band for contactless power transmission. In this embodiment, all of the power transmitting units 21 are configured so that the various parameters of the power transmitting side coil 23 and the power transmitting side capacitor 24 are identical to each other. In other words, all of the power transmitting units 21 have the same configuration.

[0021] As described above, power transmission unit 21 is embedded in the road, and therefore power transmission side coil 23 and power transmission side capacitor 24 are also embedded in the road. Power transmission unit 21 is placed in the center of a lane through which vehicle 5 passes, so that the center of power transmission side coil 23 is positioned in the center of the lane. When high-frequency power is supplied to power transmission unit 21 from inverter 12 via wiring 22, power transmission side coil 23 of power transmission unit 21 generates an AC magnetic field for transmitting power.

[0022] The wiring 22 is used to connect the inverter 12 of the power supply unit 10 to the power transmission unit 21 (i.e., the power transmission side coil 23). In this embodiment, the ground power feeding device 1 has a plurality of power transmission units 21 and a plurality of inverters 12 each corresponding to a different power transmission unit 21. Each wiring 22 connects one inverter 12 to one corresponding power transmission unit 21.

[0023] The controller 30 is, for example, a general-purpose computer, and performs various controls of the ground power feeding device 1. For example, the controller 30 is electrically connected to the inverter 12 of the power supply unit 10, and controls the inverter 12 to control power transmission by the power transmission unit 21. Specifically, for example, the controller 30 identifies the power transmission unit 21 on which the vehicle 5 having the power receiving device 50 is traveling based on the output from an arbitrary sensor (not shown), and controls the inverter 12 to supply power to the identified power transmission unit 21. The controller 30 has a processor that executes various processes, and a memory that stores programs for the processor to execute the various processes, various data used when the processor executes the various processes, and the like.

[0024] <Vehicle configuration> Next, the configuration of the vehicle 5 will be described briefly with reference to Fig. 2. As shown in Fig. 2, the vehicle 5 has a motor 41, a battery 42, a power control unit (PCU) 43, a power receiving device 50, and an electronic control unit (ECU) 45. The vehicle 5 is an electric vehicle (BEV) in which the motor 41 drives the vehicle 5, or a hybrid vehicle (HEV) in which the motor 41 and an internal combustion engine drive the vehicle 5.

[0025] The motor 41 is, for example, an AC synchronous motor, and functions as both an electric motor and a generator. When functioning as an electric motor, the motor 41 is driven by electricity stored in a battery 42 as a power source. The output of the motor 41 is transmitted to the wheels via a reducer and an axle. On the other hand, when the vehicle 5 is decelerating, the motor 41 is driven by the rotation of the wheels, and functions as a generator to generate regenerative power.

[0026] The battery 42 is a rechargeable secondary battery, and is composed of, for example, a lithium-ion battery, a nickel-metal hydride battery, or the like. The battery 42 stores the electric power required for the vehicle 5 to travel (for example, the driving power of the motor 41). When the electric power received by the power receiving device 50 from the power transmitting unit 21 is supplied, the battery 42 is charged. When the regenerative electric power generated by the motor 41 is supplied to the battery 42, the battery 42 is charged. When the battery 42 is charged, the state of charge (SOC) of the battery 42 is restored. The battery 42 may also be chargeable by an external power source other than the ground power supply device 1 via a charging port provided on the vehicle 5.

[0027] The PCU 43 is electrically connected to the battery 42 and the motor 41. The PCU 43 has an inverter, a boost converter, and a DC / DC converter. The inverter converts DC power supplied from the battery 42 into AC power and supplies the AC power to the motor 41. Meanwhile, the inverter converts AC power (regenerated power) generated by the motor 41 into DC power and supplies the DC power to the battery 42. The boost converter boosts the voltage of the battery 42 as needed when the power stored in the battery 42 is supplied to the motor 41. The DC / DC converter lowers the voltage of the battery 42 when the power stored in the battery 42 is supplied to electronic devices such as headlights.

[0028] The power receiving device 50 receives power from the power transmitting unit 21 and supplies the received power to the battery 42. The power receiving device 50 includes a power receiving side resonant circuit 51, a power receiving side rectifying circuit 54, and a charging circuit 55.

[0029] The power receiving side resonant circuit 51 is disposed at the bottom of the vehicle 5 so as to reduce the distance to the road surface. The power receiving side resonant circuit 51 has a configuration similar to that of the power transmitting unit 21, and includes a power receiving side coil 52 and a power receiving side capacitor 53. The power receiving side coil 52 is configured so that a current flows through the power receiving side coil 52 when a magnetic field is generated around it. The power receiving side coil 52 and the power receiving side capacitor 53 form a resonator. Various parameters of the power receiving side coil 52 and the power receiving side capacitor 53 (such as the outer diameter and inner diameter of the power receiving side coil 52, the number of turns of the power receiving side coil 52, and the capacitance of the power receiving side capacitor 53) are determined so that the resonant frequency of the power receiving side resonant circuit 51 matches the resonant frequency of the power transmitting unit 21. Furthermore, if the deviation between the resonant frequency of the receiving side resonant circuit 51 and the resonant frequency of the power transmitting unit 21 is small, for example, if the resonant frequency of the receiving side resonant circuit 51 is within a range of ±20% of the resonant frequency of the power transmitting unit 21, the resonant frequency of the receiving side resonant circuit 51 does not necessarily have to match the resonant frequency of the power transmitting unit 21.

[0030] 2, when the power receiving-side resonant circuit 51 faces the power transmitting unit 21 and an AC magnetic field is generated by the power transmitting unit 21, the oscillation of the AC magnetic field is transmitted to the power receiving-side resonant circuit 51, which resonates at the same resonant frequency as the power transmitting unit 21. As a result, an induced current flows in the power receiving-side resonant circuit 51 due to electromagnetic induction, and the induced current generates an induced electromotive force in the power receiving-side resonant circuit 51. In other words, the power transmitting unit 21 transmits power to the power receiving-side resonant circuit 51, and the power receiving-side resonant circuit 51 receives power from the power transmitting unit 21.

[0031] The receiving-side rectifier circuit 54 is electrically connected to the receiving-side resonant circuit 51 and the charging circuit 55. The receiving-side rectifier circuit 54 rectifies the AC power supplied from the receiving-side resonant circuit 51 to convert it into DC power, and supplies the DC power to the charging circuit 55. The receiving-side rectifier circuit 54 is, for example, an AC / DC converter.

[0032] The charging circuit 55 is electrically connected to the power receiving side rectifier circuit 54 and the battery 42. The charging circuit 55 converts the DC power supplied from the power receiving side rectifier circuit 54 to a voltage level of the battery 42 and supplies the converted power to the battery 42. When the power transmitted from the power transmitting unit 21 is supplied to the battery 42 by the power receiving device 50, the battery 42 is charged. The charging circuit 55 is, for example, a DC / DC converter.

[0033] The ECU 45 performs various controls of the vehicle 5. For example, the ECU 45 is electrically connected to a charging circuit 55 of the power receiving device 50 and controls the charging circuit 55 to control charging of the battery 42 with power transmitted from the power transmitting unit 21. The ECU 45 is also electrically connected to the PCU 43 and controls the PCU 43 to control the exchange of power between the battery 42 and the motor 41.

[0034] <Transmitter-side resonant circuit> Next, the configuration of the power transmission side resonant circuit 20 will be described with reference to Fig. 3. Fig. 3 is a diagram schematically illustrating the configuration of the ground power feeding device 1. In particular, Fig. 3 illustrates a state in which a plurality of power transmission side resonant circuits 20 are connected to one power supply unit 10. Note that in Fig. 3, only one of the plurality of power transmission side resonant circuits 20 is indicated by the reference numeral 20.

[0035] 3, multiple power transmission units 21 connected to one power supply unit 10 are arranged in a row along a lane on a road. Each power transmission unit 21 and the power supply unit 10 are connected by a wiring 22 of a separate power transmission-side resonant circuit 20. Each wiring 22 connecting each power transmission unit 21 and the power supply unit 10 has two conductors through which current flows in opposite directions.

[0036] 3, the distance between each of the plurality of power transmission units 21 arranged in a row and one power supply unit 10 is different from one another. In this embodiment, each power transmission unit 21 and the power supply unit 10 are connected by a single wiring 22 arranged without slack therebetween. Therefore, the plurality of wirings 22 connecting each of the power transmission units 21 and the power supply unit 10 have different lengths. That is, in this embodiment, the wiring 22 of each power transmission side resonant circuit 20 has a different length from the wiring 22 of the other power transmission side resonant circuits 20.

[0037] Here, since the wirings 22 of the power transmitting-side resonant circuit 20 have different lengths, different parasitic inductances are parasitic for each wiring 22. In particular, the longer the length of the wiring 22, the larger the parasitic inductance parasitic in the wiring 22. When different parasitic inductances are parasitic for each wiring 22, the resonant frequencies of the power transmitting-side resonant circuits 20 each having a different wiring 22 are different. When the resonant frequencies of the power transmitting-side resonant circuits 20 are different in this way, the resonant frequencies of some of the power transmitting-side resonant circuits 20 become different from the frequency of the AC power supplied by the power supply unit 10. Furthermore, when the resonant frequencies of the power transmitting-side resonant circuits 20 are different in this way, the resonant frequencies of some of the power transmitting-side resonant circuits 20 become different from the resonant frequency of the power receiving-side resonant circuit 51 of the vehicle 5. When the resonant frequencies of the power transmitting-side resonant circuits 20 become different from the frequency of the AC power and the resonant frequency of the power receiving-side resonant circuit 51, the transmission efficiency of contactless power transmission decreases.

[0038] Therefore, the power transmitting side resonant circuit 20 according to this embodiment is provided with a resonance compensation capacitor 25. In this embodiment, the resonance compensation capacitor 25 is connected in series with the wiring 22 midway along the wiring 22. In other words, in this embodiment, each wiring 22 has its own resonance compensation capacitor 25. Also, in this embodiment, the resonance compensation capacitor 25 is connected to one of the two conductors of each wiring 22.

[0039] The resonance compensation capacitor 25 has a capacitance that varies depending on the length of the wiring 22 of the power transmitting side resonant circuit 20 in which the resonance compensation capacitor 25 is provided. Specifically, the capacitance of the resonance compensation capacitor 25 decreases as the length of the wiring 22 increases. More specifically, the resonance compensation capacitor 25 has a capacitance that makes the resonant frequency of the power transmitting side resonant circuit 20 equal to the frequency of the AC power supplied by the power supply unit 10, even if the parasitic inductances parasitic on the wiring 22 of the power transmitting side resonant circuit 20 differ from each other.

[0040] According to this embodiment, even if the length of the wiring 22 differs for each power transmitting side resonant circuit 20 and the parasitic inductance of the wiring 22 differs, the resonant frequency of the power transmitting side resonant circuit 20 can be made equal to the frequency of the AC power supplied by the power supply unit 10. Therefore, according to this embodiment, even in such a case, the resonant frequencies of all the power transmitting side resonant circuits 20 can be made approximately the same, and the resonant frequencies of all the power transmitting side resonant circuits 20 can be made equal to the resonant frequency of the power receiving side resonant circuit 51 of the vehicle 5. Therefore, according to this embodiment, the transmission efficiency between the power transmitting unit 21 and the power receiving side resonant circuit 51 can be increased.

[0041] <Modification> In the above embodiment, the resonance compensation capacitor 25 is connected in series with the wiring 22 midway along the wiring 22. However, the resonance compensation capacitor 25 may be provided between the wiring 22 and the power transmitting unit 21, or between the wiring 22 and the inverter 12 of the power supply unit 10. Alternatively, the resonance compensation capacitor 25 may be provided within the power transmitting unit 21 (for example, between the power transmitting side coil 23 and the power transmitting side capacitor 24 of the power transmitting unit 21) as long as it is connected in series within the power transmitting side resonant circuit 20.

[0042] Furthermore, in the above embodiment, one resonance compensation capacitor 25 is provided in one power transmitting side resonant circuit 20. However, multiple resonance compensation capacitors 25 may be provided in one power transmitting side resonant circuit 20. For example, in the above embodiment, the resonance compensation capacitor 25 is connected to one of the two conductors of each wiring 22. However, a resonance compensation capacitor 25 may be connected to each of the two conductors of each wiring 22. Even in this case, the capacitance of these resonance compensation capacitors 25 is set to a value that makes the resonant frequency of the power transmitting side resonant circuit 20 equal to the frequency of the AC power supplied by the power supply unit 10.

[0043] Furthermore, in the above embodiment, all of the wirings 22 connected to the power supply unit 10 have different lengths. However, some of the wirings 22 may have the same length. FIG. 4 is a diagram similar to FIG. 3, schematically illustrating the configuration of a ground power supply device 1 according to a modification of the first embodiment. In the example illustrated in FIG. 4, the wirings of multiple power transmitting side resonant circuits 20 including multiple adjacently arranged power transmitting units 21 (power transmitting side coils 23) (specifically, the power transmitting side resonant circuit 20 including the four power transmitting units 21 on the right, the power transmitting side resonant circuit 20 including the four power transmitting units 21 in the center, and the power transmitting side resonant circuit 20 including the four power transmitting units 21 on the left) have the same length. In this way, the resonance compensation capacitors 25 in the power transmitting side resonant circuits 20 having wirings 22 of the same length have the same capacitance. As a result, the number of variations in wiring length and the number of variations in resonance compensation capacitors 25 can be reduced, which can reduce manufacturing costs and facilitate installation of the ground power supply device 1.

[0044] As described above, in this embodiment and its modified examples, the wiring 22 of the power transmitting side resonant circuit 20 has a length that is at least partially different from the wiring 22 of the other power transmitting side resonant circuits 20, and is formed so that the parasitic inductance of the wiring 22 is at least partially different from the wiring 22 of the other power transmitting side resonant circuits 20 due to the different length.

[0045] Second embodiment Next, a ground power supply device 1 according to a second embodiment will be described with reference to Fig. 5. The configuration of the ground power supply device 1 according to the second embodiment is basically the same as the configuration of the ground power supply device 1 according to the first embodiment. The following description will focus on the parts that are different from the configuration of the ground power supply device 1 according to the first embodiment.

[0046] 5 is a diagram similar to FIGS. 3 and 4, which schematically illustrates the configuration of a ground power feeding device 1 according to a second embodiment. In this embodiment, one power transmitting unit 21 and one wiring 22 also constitute one power transmitting-side resonant circuit 20. Also in FIG. 5, a plurality of power transmitting-side resonant circuits 20 are connected to one power supply unit 10.

[0047] As shown in FIG. 5, each wiring 22 has two portions: a first wiring portion 22a and a second wiring portion 22b. The first wiring portion 22a of each wiring 22 is connected to the corresponding power transmitting unit 21 and first connector 26. A plurality of first wiring portions 22a connected to a plurality of adjacently arranged power transmitting units 21 are connected to one first connector 26 (four first wiring portions 22a in the example shown in FIG. 5). Therefore, one first connector 26 is connected to a plurality of adjacently arranged power transmitting units 21. In addition, in this embodiment, all of the first wiring portions 22a have the same length. Therefore, there is no difference in the magnitude of parasitic inductance between the power transmitting side resonant circuits 20 for the first wiring portions 22a.

[0048] The second wiring portion 22b of each wiring 22 is connected to the corresponding second connector 27 and the power supply unit 10. A group of multiple second wiring portions 22b having the same length is connected to one second connector 27 (four second wiring portions 22b in the example shown in FIG. 5). In particular, the same number of second wiring portions 22b as the number of first wiring portions 22a connected to the first connector 26 are connected to the second connector 27. The second connector 27 is connected to the first connector 26, thereby connecting the second wiring portions 22b to the corresponding first wiring portions 22a. In this embodiment, multiple second wiring portions 22b having the same length are connected to the first wiring portion 22a via the same first connector 26 and the same second connector 27. Furthermore, since the first connector 26 is connected to a plurality of first wiring portions 22a connected to a plurality of adjacently arranged power transmission units 21, in the example shown in Figure 5, the wiring of a plurality of power transmission side resonant circuits 20 including a plurality of adjacently arranged power transmission units 21 (power transmission side coils 23) (specifically, the power transmission side resonant circuit 20 including the four power transmission units 21 on the right, the power transmission side resonant circuit 20 including the four power transmission units 21 in the middle, and the power transmission side resonant circuit 20 including the four power transmission units 21 on the left) has the same length.

[0049] In this embodiment, a resonance compensation capacitor 25 is provided in the second wiring portion 22b. In particular, the resonance compensation capacitor 25 is connected in series to the second wiring portion 22b midway through the second wiring portion 22b. Also in this embodiment, the resonance compensation capacitor 25 is connected to one of the two conductors of each second wiring portion 22b. Additionally, in this embodiment, the resonance compensation capacitor 25 provided in each second wiring portion 22b has a capacitance corresponding to the length of the second wiring portion 22b. Therefore, in this embodiment, the resonance compensation capacitors 25 provided in each group of multiple second wiring portions 22b with equal lengths connected to the same second connector 27 have the same capacitance. Here, all of the wirings 22 of the power transmitting-side resonant circuit 20, including the second wiring portions 22b with equal lengths, have the same length and therefore the same parasitic inductance. Therefore, since the resonance compensation capacitors 25 provided in the second wiring portions 22b have the same capacitance, the resonant frequencies of the power transmitting-side resonant circuits 20 can be made equal.

[0050] According to this embodiment, the first wiring portions 22a have the same length. Therefore, one first connector 26 and the multiple first wiring portions 22a connected thereto have the same configuration. Therefore, components can be shared when manufacturing the first connector 26 and the first wiring portions 22a. Furthermore, the second wiring portions 22b connected to one second connector 27 have the same configuration. Therefore, the number of variations in the length of the second wiring portions 22b and the number of variations in the resonance compensation capacitors 25 can be reduced relative to the number of power transmitting units 21, thereby reducing manufacturing costs and facilitating the installation of the ground power feeding device 1. Furthermore, even though the power transmitting units 21 are arranged at different positions, the first wiring portions 22a connected to the multiple power transmitting units 21 are connected to the second wiring portions 22b at the same point by the first connector 26 and the second connector 27, making it easier to manage the wiring.

[0051] On the other hand, in the present embodiment, the first wiring portion 22a is not provided with a resonance compensation capacitor 25. Therefore, in the present embodiment, the capacitance of the resonance compensation capacitor 25 provided in the second wiring portion 22b is set in consideration of the length of the wiring 22 including the first wiring portion 22a and the second wiring portion 22b. Furthermore, in the present embodiment, the length of the first wiring portion 22a is the same in all of the power transmitting-side resonant circuits 20, so the capacitance of the resonance compensation capacitor 25 provided in the second wiring portion 22b and the capacitance of the power transmitting-side capacitor 24 of the power transmitting unit 21 can be set in consideration of the parasitic inductance generated in the first wiring portion 22a. Since the first wiring portion 22a does not have a resonance compensation capacitor 25 in this way, the first wiring portion 22a can have a simple configuration.

[0052] In the above embodiment, four wiring portions 22a, 22b are connected to each connector 26, 27. However, a number other than four wiring portions 22a, 22b may be connected to each connector 26, 27 as long as a plurality of wiring portions 22a, 22b are connected to each connector 26, 27. Therefore, a group of second wiring portions 22b of equal length may include a plurality of second wiring portions 22b other than four.

[0053] A resonance compensation capacitor may also be provided on the first wiring portion 22a. In this case, since all of the first wiring portions 22a have the same length, the capacitance of the resonance compensation capacitor provided on all of the first wiring portions 22a is also the same. Furthermore, the first wiring portion 22a has a capacitance corresponding to the length of the first wiring portion 22a so as to cancel out the effect of parasitic inductance on the first wiring portion 22a on the resonance frequency of the power transmitting unit 21.

[0054] Third embodiment Next, a ground power supply device 1 according to a third embodiment will be described with reference to Fig. 6. The configuration of the ground power supply device 1 according to the third embodiment is basically the same as the configuration of the ground power supply device 1 according to the second embodiment. Therefore, the following description will focus on the parts that are different from the configuration of the ground power supply device according to the second embodiment.

[0055] Fig. 6 is a diagram similar to Figs. 3 to 5, which schematically illustrates the configuration of a ground power feeding device 1 according to a third embodiment. As shown in Fig. 6, in this embodiment as well, each wiring 22 has a first wiring portion 22a and a second wiring portion 22c. The first wiring portion 22a of each wiring 22 is connected to a corresponding power transmission unit 21 and a selector switch 28. A single selector switch 28 is connected to a plurality of first wiring portions 22a that are connected to a plurality of adjacently arranged power transmission units 21. Also in this embodiment as well, all of the first wiring portions 22a have the same length.

[0056] On the other hand, in this embodiment, one second wiring portion 22c is connected to one changeover switch 28. Therefore, one second wiring portion 22c is connected to multiple first wiring portions 22a via the changeover switch 28. The multiple second wiring portions 22c are connected to different changeover switches 28 and a single common power supply unit 10. In this embodiment, one second wiring portion 22c is shared by multiple power transmitting side resonant circuits 20. In any case, in this embodiment as well, one power transmitting unit 21 and one wiring 22 configure one power transmitting side resonant circuit 20.

[0057] Also in this embodiment, the second wiring portion 22c is provided with a resonance compensation capacitor 25. Also in this embodiment, the resonance compensation capacitor 25 provided in each second wiring portion 22c has a capacitance according to the length of the second wiring portion 22c.

[0058] Each changeover switch 28 is connected to a plurality of power transmission units 21 via a plurality of first wiring portions 22a, and is connected to the power supply unit 10 via one second wiring portion 22c. The changeover switch 28 selectively connects one of the plurality of first wiring portions 22a connected to the changeover switch 28 to the second wiring portion 22c. Therefore, the changeover switch 28 selectively connects one of the plurality of power transmission units 21 to the power supply unit 10. In other words, the changeover switch 28 switches the power transmission unit 21 connected to the power supply unit 10.

[0059] The changeover switch 28 is connected to and controlled by the controller 30. The controller 30 identifies the power transmitting unit 21 on which the vehicle 5 having the power receiving device 50 is traveling based on, for example, an output from an arbitrary sensor (not shown), and switches the changeover switch 28 so that the identified power transmitting unit 21 and the power supply unit 10 are connected.

[0060] According to this embodiment, one second wiring portion 22c is connected to multiple power transmitting units 21. That is, one second wiring portion 22c is shared by multiple power transmitting side resonant circuits 20. This makes it easier to install the second wiring portion 22c. In addition, the number of inverters 12 required in the power supply unit 10 can be reduced, thereby reducing the manufacturing cost of the power supply unit 10.

[0061] Fourth embodiment Next, a ground power supply device 1 according to a fourth embodiment will be described with reference to Fig. 7 and Fig. 8. The configuration of the ground power supply device 1 according to the fourth embodiment is basically the same as the configuration of the ground power supply device 1 according to the first embodiment. Therefore, the following description will mainly focus on parts that are different from the configuration of the ground power supply device 1 according to the first embodiment.

[0062] In the ground power supply device 1 according to the first embodiment, each power transmission unit 21 and the power supply unit 10 are connected by a single wiring 22 of different lengths. In contrast, in the ground power supply device 1 according to the present embodiment, each power transmission unit 21 and the power supply unit 10 are connected by a plurality of wiring modules 29 connected in series.

[0063] Fig. 7 is a diagram schematically illustrating the configuration of each wiring module 29. As shown in Fig. 7, each wiring module 29 includes a cable 35, a resonance compensation capacitor 25 connected in series to the cable 35, and a connector 36.

[0064] As shown in FIG. 7 , each wiring module 29 has two cables 35 through which currents flow in opposite directions. In this embodiment, each wiring module 29 has one resonance compensation capacitor 25, and the resonance compensation capacitor 25 is connected to one of the two cables 35. Both ends of the two cables 35 are connected to connectors 36, respectively. The connector 36 of each wiring module 29 can be connected to a connector 36 of another wiring module 29. Note that each wiring module 29 may have multiple resonance compensation capacitors 25. In this case, one or more resonance compensation capacitors 25 are connected to each cable 35.

[0065] In this embodiment, all of the wiring modules 29 are configured so that their cables 35 have the same length and their resonance compensation capacitors 25 have the same capacitance. In particular, in this embodiment, the lengths of the cables 35 of all of the wiring modules 29 are equal to the interval between adjacently arranged power transmitting units 21 (particularly the interval between adjacently arranged power transmitting coils 23). Furthermore, the resonance compensation capacitors 25 have a capacitance that cancels out the effect of parasitic inductance in the cables 35 constituting each wiring module 29 on the resonance frequency of the power transmitting unit 21 (i.e., the resonance frequency generated in the power transmitting coil 23).

[0066] FIG. 8 is a diagram schematically illustrating the configuration of a ground power supply device 1 according to a fourth embodiment. As shown in FIG. 8, each wiring 22 connects one power transmission unit 21 and a power supply unit 10. The wirings 22 have different lengths. In this embodiment, each wiring 22 is configured by connecting a plurality of wiring modules 29 in series. As described above, the cables 35 of all the wiring modules 29 have the same length, and therefore the lengths of the wirings 22 differ depending on the number of wiring modules 29 that make up the wiring 22. Therefore, the wiring 22 used for a power transmission unit 21 that is farther away from the power supply unit 10 is configured with more wiring modules 29.

[0067] According to this embodiment, all of the wiring 22 is formed by a plurality of wiring modules 29 having the same configuration. Therefore, it is not necessary to use individual wiring configurations equipped with resonance compensation capacitors having different capacitances for each of the wirings 22 having different lengths. This makes it easier to manufacture the wiring 22 and also makes it easier to handle the wiring 22 when installing the power transmitting side resonant circuit 20.

[0068] In the above embodiment, all of the wirings 22 connected to the power supply unit 10 have different lengths. However, as in the example shown in Fig. 4, some of the wirings 22 may have the same length. In this case, the wirings 22 having the same length are configured by connecting the same number of wiring modules 29 in series.

[0069] Furthermore, in the above-described embodiment, all of the wiring 22 extending from the power supply unit 10 to each power transmitting unit 21 is formed by the wiring modules 29. However, only a portion of each wiring 22 may be formed by the wiring modules 29. For example, in the second and third embodiments described above, only the second wiring portions 22b and 22c may be formed by connecting the wiring modules 29 in series, and the first wiring portion 22a may be formed without using the wiring modules 29. Note that, when only the second wiring portions 22b and 22c are formed by the wiring modules 29 in this manner, the length of the cables 35 of all the wiring modules 29 is set to a length that is an integer multiple of at least two times the spacing between adjacently arranged power transmitting units 21 (particularly, the spacing between adjacently arranged power transmitting coils 23). In particular, in the example shown in FIGS. 5 and 6 , four power transmitting units 21 are grouped together, and therefore the length of the cables 35 of all the wiring modules 29 is set to four times the spacing between adjacently arranged power transmitting units 21.

[0070] In all the above embodiments, the ground power supply device 1 supplies power to a moving vehicle 5 in a wireless manner. However, the ground power supply device 1 may also supply power to a vehicle 5 that is not moving, such as a parked vehicle 5, in a wireless manner. Specifically, the ground power supply device 1 is provided, for example, in a parking lot having a plurality of parking spaces, and a power transmission unit 21 is provided in each of the plurality of parking spaces.

[0071] Although the preferred embodiments according to the present disclosure have been described above, the present disclosure is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims. [Explanation of symbols]

[0072] 1 Ground power supply equipment 5 vehicles 10 Power Supply Unit 20 Transmission side resonant circuit 21 Power Transmission Unit 22 Wiring 25 Resonance compensation capacitor 30 Controllers

Claims

1. A ground power supply device that transmits power to a vehicle in a non-contact manner, a plurality of resonant circuits; and a single power supply source that supplies AC power of the same frequency to all of the resonant circuits; Each resonant circuit has a coil embedded in the road for contactlessly transmitting power, and wiring connecting each coil to the power supply source, the wiring of each resonant circuit has a length at least partially different from the wiring of the other resonant circuits, and is formed so that the difference in length causes a parasitic inductance of the wiring to be at least partially different from the wiring of the other resonant circuits; The resonant circuits further include capacitors having different capacitances so that the resonant frequencies of all the resonant circuits are equal even if the parasitic inductances of the wiring are different.

2. 2. The ground power feeding device according to claim 1, wherein the capacitor has a capacitance such that the resonant frequencies of all the resonant circuits are the same as the frequency of the AC power even if the parasitic inductances of the wiring are different.

3. 3. The ground power feeding device according to claim 1, wherein the wiring of a plurality of resonant circuits including a plurality of coils arranged adjacent to each other has the same length.

4. the wiring has a first portion having the same length in all the resonant circuits and a second portion having a length that partially differs between the resonant circuits; The ground power feeding device according to claim 1 or 2, wherein the capacitor is provided in the second section.

5. 5. The ground power feeding device according to claim 4, wherein the capacitors provided in the plurality of second portions having the same length have the same capacitance.

6. The ground power supply device of claim 4 , wherein the first section does not include a capacitor.

7. 5. The ground power supply device according to claim 4, wherein the first portion is connected to the coil, the second portion is connected to the power supply source, and a plurality of the second portions having the same length are connected to the first portion by the same connector.

8. the wiring is at least partially formed by connecting in series a plurality of wiring modules, each having a cable of the same length and a capacitor connected to the cable; the capacitor of each wiring module has a capacitance that cancels out the effect of parasitic inductance in the cable of the wiring module on the resonance frequency that occurs in the coil at the frequency of the AC power, 3. The ground power feeding device according to claim 1, wherein the resonant circuits each having wiring of different lengths have different lengths of wiring due to a difference in the number of the wiring modules constituting the wiring of the resonant circuits.

9. The ground power feeding device according to claim 8 , wherein a length of the cable of the wiring module is equal to an integer multiple of a distance between adjacent coils.

10. A wiring used in a resonant circuit of a ground power feeding device that transmits power to a vehicle in a wireless manner, the wiring including a plurality of resonant circuits and a single power supply source that supplies AC power of the same frequency to all of the resonant circuits, The wiring of each resonant circuit connects each coil of the resonant circuit embedded in the road for contactless power transmission to the power supply source, the wiring of each resonant circuit has a length at least partially different from the wiring of the other resonant circuits, and is formed so that the difference in length causes a parasitic inductance of the wiring to be at least partially different from the wiring of the other resonant circuits; Each wiring has a capacitor with a different capacitance so that the resonant frequencies of all the resonant circuits are the same even if the parasitic inductances of the wiring are different.

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