Power reception device

Abstract

A power reception device (100) comprises a main power reception coil (102, 110, 130, 401-404, 501, 502, 601-603), and power is supplied from a power transmission coil (22) of a power transmission device (20) to the main power reception coil in a non-contact manner. The power reception device comprises: a sub-power reception coil (103-105, 410-412, 510, 610) that is magnetically coupled to the main power reception coil; shorting switches (QL1, QL2, 400); and a drive circuit (353, 354A, 354B) that is connected to a power storage unit (302) via an electrical path (351) and that controls the shorting switches. Turning on the shorting switches forms a closed circuit that includes the main power reception coil and the shorting switches. The drive circuit is configured to be operable when being supplied with power. The drive circuit is supplied with the power that is received by the sub-power reception coil.

Description

Power receiving device Cross-reference to related applications

[0001] This application is based on Japanese Application No. 2024-196584 filed on November 11, 2024, the contents of which are incorporated herein by reference.

[0002] This disclosure relates to a power receiving device.

[0003] Patent Document 1 discloses a system for non-contact power supply from a power transmission device on the ground side to a power receiving device mounted on an electric vehicle. The power transmission device includes a power transmission coil and a control unit that energizes the power transmission coil. The power receiving device includes a power receiving coil that is non-contact power-supplied from the power transmission coil.

[0004] Japanese Unexamined Patent Application Publication No. 2024-330

[0005] The electrical connection between the power supply target device (for example, a high-voltage battery) that is the power supply destination of the power received by the power receiving coil and the power receiving coil may be interrupted due to some factor. In this case, there is a concern that an overvoltage abnormality may occur in the power receiving device.

[0006] Therefore, the power receiving device includes a short-circuit switch and a drive circuit that turns on and off the short-circuit switch. When the short-circuit switch is turned on, a closed circuit including the power receiving coil and the short-circuit switch is formed. This suppresses the occurrence of overvoltage abnormalities.

[0007] Here, the drive circuit is configured to be operable by being supplied with power from a power storage unit via an electrical path. If the power supply from the power storage unit to the drive circuit is interrupted due to a disconnection or the like in the electrical path, there is a concern that the short-circuit switch cannot be turned on. For this reason, a technique that can turn on the short-circuit switch even when the power supply from the power storage unit to the drive circuit is interrupted is desired. Note that this technique is also desired when the power transmission device is a vehicle-side device and the power receiving device is a ground-side device.

[0008] The main object of this disclosure is to provide a power receiving device that can turn on a short-circuit switch even when the power supply from a power storage unit to a drive circuit is interrupted.

[0009] This disclosure relates to a power receiving device having a power receiving coil, which is supplied with power from a power transmitting coil of a power transmitting device in a non-contact manner, wherein the power receiving coil comprises: a main power receiving coil and a sub-power receiving coil, which is a separate coil from the main power receiving coil and is magnetically coupled to the main power receiving coil; a short-circuit switch and a drive circuit connected to a power storage unit via an electrical path and controlling the short-circuit switch, wherein when the short-circuit switch is turned on, it forms a closed circuit including the main power receiving coil and the short-circuit switch; the drive circuit is configured to be operable when power is supplied; and the power received by the sub-power receiving coil is supplied to the drive circuit.

[0010] According to this disclosure, even if the power supply from the energy storage unit to the drive circuit is interrupted, the sub-power receiving coil can secure the operating power for the drive circuit. This allows the short-circuit switch to be turned on, thereby suppressing the occurrence of overvoltage abnormalities.

[0011] The above-mentioned objectives and other objectives, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. The drawings are as follows: Figure 1 is an overall configuration diagram of the non-contact power supply system according to the first embodiment; Figure 2 is an overall configuration diagram of the non-contact power supply system; Figure 3 is a diagram showing the power transmission device and power receiving device; Figure 4 is a diagram showing the electrical circuit of the power receiving device; Figure 5 is a diagram showing the short-circuit operation in which the two lower arm switches are turned on; Figure 6 is a diagram showing the power transmission device and power receiving device according to the second embodiment; Figure 7 is a diagram showing the electrical circuit of the power receiving device; Figure 8 is a diagram showing the electrical circuit of the power receiving device according to a comparative example; Figure 9 is a plan view of the first main power receiving coil; Figure 10 is a plan view of the first and second main power receiving coils and the power transmission coil; Figure 11 is a calculation result showing the relationship between the positional displacement of the main power receiving coil relative to the power transmission coil and the coupling coefficient between the power transmission coil and the main power receiving coil. Figure 12 is a plan view of the first main power receiving coil according to Comparative Example 1, Figure 13 is a plan view of the first main power receiving coil according to Comparative Example 2, Figure 14 is a plan view of the first main power receiving coil according to a modified example of the second embodiment, Figure 15 is a plan view of the first main power receiving coil according to a modified example of the second embodiment, Figure 16 is a plan view of the main power receiving coil according to the third embodiment, Figure 17 is a plan view of the main power receiving coil, Figure 18 is a plan view of the main power receiving coil according to a modified example of the third embodiment, Figure 19 is a plan view of the main power receiving coil according to a modified example of the third embodiment, Figure 20 is a plan view of the main power receiving coil according to the fourth embodiment, Figure 21 is a plan view of the main power receiving coil according to another embodiment, and Figure 22 is a diagram showing a power receiving device according to another embodiment.

[0012] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the descriptions of other embodiments.

[0013] <First Embodiment> The first embodiment of the contactless power supply system according to this disclosure will be described below with reference to the drawings.

[0014] First, the overall configuration of the contactless power supply system will be explained. As shown in Figures 1, 2, and 3, the contactless power supply system 10 comprises a power transmission device 20 and a power receiving device 100. The power receiving device 100 is a vehicle-side device mounted on a vehicle 11, which is a mobile body traveling on a road RS. The vehicle 11 is, for example, an electric vehicle or a hybrid vehicle. Power is supplied from the power transmission device 20 to the power receiving device 100 while the vehicle 11 is moving or stopped. The contactless power supply system 10 performs wireless power transmission from the power transmission device 20 to the power receiving device 100 by magnetic field resonance coupling (magnetic resonance). The contactless power supply system 10 is also called a dynamic wireless power transmission (D-WPT) system.

[0015] The power transmission device 20 is a ground-side device comprising a power transmission coil unit 21 and a power transmission power supply unit 51 that supplies power to the power transmission coil unit 21. The power transmission device 20 is, for example, a stationary device. The power transmission coil unit 21 is installed (for example, buried) in a road RS or parking lot, etc. The power transmission power supply unit 51 is installed, for example, next to a road RS. The power transmission coil unit 21 is connected to the power transmission power supply unit 51. The power transmission power supply unit 51 is connected to an AC power source 15 and supplies AC power from the AC power source 15 to the power transmission coil unit 21. The AC power source 15 is, for example, a commercial power source. Multiple power transmission coil units 21 are arranged along the lanes of the road RS.

[0016] Figure 2 shows an example in which one power transmission coil unit 21 is connected to one power transmission power supply unit 51. Multiple power transmission coil units 21 are arranged in a line at predetermined intervals in the direction of vehicle travel. The spacing between each power transmission coil unit 21 is such that the distance between the centers of each power transmission coil unit 21 in the direction of vehicle travel is approximately 1.5 to 2 m, and the distance between each power transmission coil unit 21 is approximately 0.5 to 0.8 m. In Figure 2, the spacing between each power transmission coil unit 21 is denoted as D1.

[0017] The power transmission power supply unit 51 includes a PFC circuit 61, an inverter 60, and a filter circuit 52. The PFC circuit 61 includes an AC / DC converter and is connected to the AC power supply 15. By switching the switching elements (e.g., IGBTs or MOSFETs) of the PFC circuit 61, the power factor of the AC power input from the AC power supply 15 is improved, and the input AC power is converted to DC power.

[0018] The inverter 60 is connected to the PFC circuit 61. By switching the switching elements (e.g., IGBTs or MOSFETs) of the inverter 60, the DC power input from the PFC circuit 61 is converted into AC power.

[0019] The filter circuit 52 removes noise contained in the AC current input from the inverter 60 and supplies the noise-free AC current to the power transmission coil unit 21. The filter circuit 52 is, for example, an LC filter including a coil and a capacitor. Various configurations of circuits can be used as the filter circuit 52; specifically, for example, a T-type filter circuit is used.

[0020] The power transmission coil unit 21 comprises a power transmission coil 22, a power transmission resonant circuit 30, and a power transmission communication coil 40. The power transmission resonant circuit 30 supplies AC power supplied from the filter circuit 52 to the power transmission coil 22. Various well-known resonant circuits, such as a circuit equipped with a resonant capacitor, can be used as the power transmission resonant circuit 30.

[0021] The power receiving device 100 comprises a power receiving coil unit 101 and a power receiving power supply unit 181. The power receiving coil unit 101 includes a main power receiving coil 102. The power receiving coil unit 101 is located at the bottom of the vehicle body 11. The power receiving coil unit 101 is located at the bottom of the vehicle body and faces the ground surface. When the vehicle 11 travels on the road RS in which the power transmission coil 22 is buried, the power transmission coil 22 on the ground and the main power receiving coil 102 of the vehicle 11 face each other in the vertical direction.

[0022] The power receiving device 100 includes a power receiving side resonant circuit 140. The main power receiving coil 102 is connected to the power receiving side resonant circuit 140. Power is supplied to the main power receiving coil 102 from the power transmitting coil 22. The main power receiving coil 102 supplies the received power to the power receiving side resonant circuit 140. Various well-known resonant circuits, such as a circuit equipped with a resonant capacitor, can be used as the power receiving side resonant circuit 140.

[0023] The power receiving device 100 includes a filter circuit 182, a rectifier circuit 200 that functions as a DC-AC conversion circuit, and a smoothing capacitor 210. The filter circuit 182 removes noise contained in the AC current input from the power receiving side resonant circuit 140 and supplies the noise-free AC current to the rectifier circuit 200. In this embodiment, the filter circuit 182 is, for example, an LC filter comprising a reactor and a capacitor.

[0024] As shown in Figure 4, the receiving-side resonant circuit 140 includes a first resonant capacitor 141 and a second resonant capacitor 142. Note that the receiving-side resonant circuit 140 is not limited to the circuit shown in Figure 4; various other circuits can be used.

[0025] The filter circuit 182 removes noise contained in the AC current input from the power receiving side resonant circuit 140 and supplies the noise-free AC current to the rectifier circuit 200. The filter circuit 182 in this embodiment is an LC filter comprising a first reactor 183, a second reactor 184, and a capacitor 185. The first end of the first reactor 183 is connected to the first end of the main power receiving coil 102 via a first resonant capacitor 141. The first end of the second reactor 184 is connected to the second end of the main power receiving coil 102 via a second resonant capacitor 142. The first end of the first reactor 183 and the first end of the second reactor 184 are connected by a capacitor 185. Note that the filter circuit 182 is not limited to the circuit shown in Figure 4, and various other circuits can be used.

[0026] The rectifier circuit 200 is a full-bridge circuit and includes a first upper arm switch QH1, a first lower arm switch QL1, a second upper arm switch QH2, and a second lower arm switch QL2. In this embodiment, each switch QH1, QL1, QH2, and QL2 is a semiconductor switching element, specifically an N-channel MOSFET. Each switch QH1, QL1, QH2, and QL2 has body diodes DH1, DL1, DH2, and DL2. The rectifier circuit 200 is also called an ERB (Electronic Rectification Box). The rectifier circuit 200 may also include an IGBT instead of the N-channel MOSFET. In this case, a freewheeling diode is connected in antiparallel to the IGBT.

[0027] The source terminal of the first upper arm switch QH1, which is the low-potential side terminal, and the drain terminal of the first lower arm switch QL1, which is the high-potential side terminal, are connected to the second terminal of the first reactor 183, which constitutes the filter circuit 182. The source terminal of the second upper arm switch QH2 and the drain terminal of the second lower arm switch QL2 are connected to the second terminal of the second reactor 184, which constitutes the filter circuit 182.

[0028] The power receiving device 100 is equipped with a smoothing capacitor 210. The smoothing capacitor 210 connects the drains of the first and second upper arm switches QH1 and QH2 to the sources of the first and second lower arm switches QL1 and QL2.

[0029] Vehicle 11 is equipped with a high-potential side main switch 301H, a low-potential side main switch 301L, and a high-voltage battery 300 as the device to be powered. The high-potential side main switch 301H and the low-potential side main switch 301L are, for example, relays (specifically, mechanical relays). The positive terminal of the high-voltage battery 300 is connected to the high-potential side output terminal of the rectifier circuit 200 via the high-potential side main switch 301H. The negative terminal of the high-voltage battery 300 is connected to the low-potential side output terminal of the rectifier circuit 200 via the low-potential side main switch 301L. The high-voltage battery 300 is a rechargeable secondary battery and has a rated voltage of, for example, several hundred volts. The high-voltage battery 300 is, for example, a lithium-ion battery or a nickel-metal hydride battery.

[0030] Vehicle 11 is equipped with a traction inverter 310 and a rotating electric machine 320. The traction inverter 310 is a three-phase inverter and is connected to a high-voltage battery 300 via a high-potential main switch 301H and a low-potential main switch 301L. The armature windings of the rotating electric machine 320 are connected to the upper and lower arm switches that make up the traction inverter 310. When the high-potential main switch 301H and the low-potential main switch 301L are turned ON, the upper and lower arm switches of the traction inverter 310 are switched, causing the traction inverter 310 to convert the DC power supplied from the high-voltage battery 300 into AC power and supply it to the armature windings. As a result, the rotor of the rotating electric machine 320 rotates, and the rotational power of the rotor rotates the wheels 12 (drive wheels) of vehicle 11. As a result, vehicle 11 moves.

[0031] As shown in Figure 3, the power transmission side power supply unit 51, which constitutes the power transmission device 20, includes a power transmission side control unit 70. The power transmission side control unit 70 includes a power transmission side control device 71. The power transmission side control device 71 is an electronic control unit (ECU) that performs various controls on the power transmission device 20, and includes a processor as hardware, a memory unit, and a communication bus connecting the processor and the memory unit.

[0032] The memory unit includes memory and storage as hardware. The memory is a storage device for storing data used in processing by the power transmission control device 71. The memory provides the processor with a temporary workspace for use when the processor is performing processing. The memory includes, for example, ROM or RAM. The storage is a storage device that stores various programs and data for the processor to read and execute, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or flash memory. The storage stores program information and the like for processing described later.

[0033] The power receiving unit 181, which constitutes the power receiving device 100, includes a power receiving control device 231. The power receiving control device 231 is an ECU that performs various controls of the power receiving device 100, and as shown in Figure 4, it includes a processor 232 as hardware, a storage unit 233, and a communication bus 234 that connects the processor 232 and the storage unit 233.

[0034] The memory unit 233 includes memory and storage as hardware. The memory is a storage device for storing data used in processing by the power receiving control device 231. The memory provides the processor 232 with a temporary workspace for use when the processor 232 performs processing. The memory includes, for example, ROM or RAM. The storage is a storage device that stores various programs and data for the processor 232 to read and execute, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or flash memory. The storage stores program information and the like for processing described later.

[0035] For example, program information stored on a non-transitional physical recording medium is installed in the storage unit 233. The recording medium is, for example, a USB memory stick, a CD-ROM, or a DVD. In addition, program information transmitted via a communication network, such as OTA (Over The Air), is also installed in the storage unit 233.

[0036] The power transmission control device 71 controls the switching of the PFC circuit 61 and the inverter 60. The switching control of the inverter 60 applies a high-frequency AC voltage to the power transmission coil 22. This causes a high-frequency current to flow through the power transmission coil 22, generating a magnetic field for power transmission.

[0037] In this embodiment, the power transmission side control device 71 switches the inverter 60 so that the frequency of the high-frequency voltage applied to the power transmission coil 22 is 10 kHz or higher and 100 GHz or lower, which is a first specified frequency (specifically, 85 kHz). The resonant frequencies of the power transmission side resonant circuit 30 and the power receiving side resonant circuit 140 are set to the same frequency as the first specified frequency or a frequency close to the first specified frequency.

[0038] When the magnetic field generated in the transmission coil 22 links with the main receiving coil 102 of the vehicle 11, a high-frequency current fluctuates with the frequency of the high-frequency current flowing through the transmission coil 22 flows through the main receiving coil 102. The high-frequency current flowing through the main receiving coil 102 is supplied to the rectifier circuit 200 via the receiving-side resonant circuit 140 and the filter circuit 182. The receiving-side control device 231 converts the supplied AC current into DC current and outputs it by performing switching control (in other words, synchronous rectification control) of each switch QH1, QL1, QH2, and QL2. When the high-potential side main switch 301H and the low-potential side main switch 301L are turned ON, the output current of the rectifier circuit 200 is supplied to the high-voltage storage battery 300 and the traction inverter 310.

[0039] Note that the high-potential side main switch 301H and the low-potential side main switch 301L can actually be controlled by a control device other than the power receiving side control device 231. However, in this embodiment, for convenience, the high-potential side main switch 301H and the low-potential side main switch 301L are assumed to be controlled by the power receiving side control device 231.

[0040] Vehicle 11 is equipped with a low-voltage battery 302. The rated voltage of the low-voltage battery 302 is lower than the rated voltage of the high-voltage battery 300. The low-voltage battery 302 is, for example, a lead-acid battery. The low-voltage battery 302 is connected to the power receiving control device 231 via a first electrical path 350. The first electrical path 350 includes a harness and switches, etc. The power receiving control device 231 becomes operational when power is supplied from the low-voltage battery 302 via the first electrical path 350.

[0041] Vehicle 11 is equipped with a voltage sensor 330 and a current sensor 340. The voltage sensor 330 detects the voltage of various mounted equipment on vehicle 11 (specifically, components of the power receiving device 100), for example, the voltage of the smoothing capacitor 210. The current sensor 340 detects the current flowing through various mounted equipment on vehicle 11 (specifically, components of the power receiving device 100), for example, the current flowing through the main power receiving coil 102 and the rectifier circuit 200. The detected values ​​from the voltage sensor 330 and the current sensor 340 are input to the power receiving side control device 231.

[0042] The power receiving device 100 and the power transmitting device 20 are configured for communication between the power receiving device 100 and the power transmitting device 20. Specifically, the power receiving coil unit 101 that constitutes the power receiving device 100 is equipped with a power receiving communication coil 170 (corresponding to a "power receiving communication antenna"). The power receiving control unit 230 is equipped with a transmitter 240.

[0043] The power transmission side coil unit 21 that constitutes the power transmission device 20 includes a power transmission side communication coil 40 (corresponding to a "power transmission side communication antenna"). The power transmission side control unit 70 includes a receiver 80. The power reception side communication coil 170 and the power transmission side communication coil 40 are communication coils for performing short-range wireless communication. Short-range wireless communication is communication with a communication distance of less than 10 meters (for example, a maximum of 3 meters). Short-range wireless communication is communication with a shorter communication distance compared to wide-area wireless communication.

[0044] Note that as the short-range wireless communication, various short-range wireless communications can be used. For example, communication conforming to any communication standard formulated by IEEE, ISO, IEC, etc. is used. Specifically, for example, as the short-range wireless communication, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), RFID (Radio Frequency Identification), or DSRC (Dedicated Short Range Communication) is used.

[0045] A transmitter 240 is connected to the power reception side control device 231. The power reception side communication coil 170 is connected to the transmitter 240. The power reception side control device 231 controls the transmitter 240 to supply the power supply request signal COMM to the power reception side communication coil 170. The power supply request signal COMM is a signal that requests power transmission to the main power reception coil 102 from the power transmission coil 22 near the vehicle 11.

[0046] The power reception side control unit 230 supplies the vehicle side signal including the power supply request signal COMM to the power reception side communication coil 170 in one frame. In the present embodiment, the power supply request signal COMM includes the ID information of the vehicle 11 and the required power Weq which is the required value of the power supply power for the vehicle 11. When the vehicle side signal is supplied to the power reception side communication coil 170, a high-frequency voltage is applied from the transmitter 240 to the power reception side communication coil 170. As a result, a high-frequency current flows through the power reception side communication coil 170, and a magnetic field for information communication is generated in the power reception side communication coil 170.

[0047] When the power receiving side coil unit 101 of the vehicle 11 approaches the power transmitting side coil unit 21 on the ground side, when the magnetic field generated from the power receiving side communication coil 170 intersects the power transmitting side communication coil 40, a high-frequency current flows through the power transmitting side communication coil 40. This high-frequency current is input to the receiver 80. The receiver 80 recognizes the presence or absence of a power supply request and ID information based on the input signal of the power transmitting side communication coil 40. Further, the receiver 80 acquires the required power Weq of the vehicle 11 having the recognized ID information based on the signal of the power transmitting side communication coil 40. The information recognized by the receiver 80 and the required power Weq are input to the power transmitting side control device 71.

[0048] In the present embodiment, the power receiving side control device 231 controls the transmitter 240 so that the frequency of the high-frequency voltage applied to the power receiving side communication coil 170 becomes a second specified frequency of 10 kHz or more and 100 GHz or less. In the present embodiment, the second specified frequency is a frequency deviated from the first specified frequency, specifically, a frequency higher than the first specified frequency (specifically, 13.56 MHz).

[0049] The power transmitting side control device 71 determines whether or not to energize the power transmitting coil 22 based on the input signal from the receiver 80. Specifically, the power transmitting side control device 71 applies a high-frequency voltage to the power transmitting coil 22 by switching control of the inverter 60 and the PFC circuit 61 on the condition that it is determined from the input signal from the receiver 80 that there is a power supply request. Thereby, power is transmitted non-contact from the power transmitting coil 22 to the main power receiving coil 102. On the other hand, when the power transmitting side control device 71 determines that there is no power supply request, it stops the switching control of the PFC circuit 61 and the inverter 60. As a result, the switches of the PFC circuit 61 and the inverter 60 are maintained off, and the power transmitting coil 22 is not energized.

[0050] The power receiving device 100 is equipped with a configuration to protect itself from malfunctions in the event of an abnormality related to contactless power supply. Specifically, as shown in Figure 4, the power receiving device 100 includes a drive circuit 353. A low-voltage battery 302 is connected to the drive circuit 353 via a second electrical path 351. The second electrical path 351 includes a harness and switches, etc. The drive circuit 353 becomes operational when power is supplied from the low-voltage battery 302 to the drive circuit 353 via the second electrical path 351.

[0051] When the drive circuit 353 determines, for example, that a short-circuit command has been input from the power receiving control device 231, it performs a short-circuit operation by turning on only the first and second lower arm switches QL1 and QL2 (corresponding to the "short-circuit switch") among the first and second upper and lower arm switches QH1, QL1, QH2, and QL2 that constitute the rectifier circuit 200. As a result, as shown in Figure 5, a closed circuit is formed including the main power receiving coil 102, the power receiving resonant circuit 140, the filter circuit 182, and the first and second lower arm switches QL1 and QL2, and current flows through this closed circuit. As a result, the power receiving device 100 can be protected from overvoltage.

[0052] For example, if the voltage of the smoothing capacitor 210 or the voltage of the main power receiving coil 102 detected by the voltage sensor 330 exceeds a voltage threshold, the power receiving control device 231 determines that an overvoltage abnormality has occurred and transmits a short-circuit command to the drive circuit 353.

[0053] The drive circuit 353 may also perform a short-circuit operation by turning on only the first and second upper arm switches QH1 and QH2 among the first and second upper and lower arm switches QH1, QL1, QH2, and QL2. Alternatively, the drive circuit 353 may receive the detected value from the voltage sensor 330. In this case, the drive circuit 353 may determine whether or not an overvoltage abnormality has occurred based on the detected value from the voltage sensor 330 and perform a short-circuit operation.

[0054] However, a break in the second electrical path 351 or the like may prevent power from being supplied from the low-voltage battery 302 to the drive circuit 353. In this case, there is a concern that the first and second lower arm switches QL1 and QL2 may not be able to be turned on despite the occurrence of an overvoltage abnormality.

[0055] Furthermore, a break in the first electrical path 350 or the like may prevent power from being supplied from the low-voltage battery 302 to the power receiving control device 231. In this case, even though an overvoltage abnormality has occurred, the power receiving control device 231 may not be able to send a short-circuit command to the drive circuit 353, raising concerns that the first and second lower arm switches QL1 and QL2 may not be able to be turned on.

[0056] To address these issues, the power receiving device 100 is equipped with a sub-power receiving coil 103 and a regulator 360. The sub-power receiving coil 103 is provided in the power receiving coil unit 101 that constitutes the power receiving device 100. The sub-power receiving coil 103 is a separate coil from the main power receiving coil 102 and is magnetically coupled to the main power receiving coil 102.

[0057] The sub-receiving coil 103 is connected to the regulator 360. The sub-receiving coil 103, along with the main receiving coil 102, receives power from the transmitting coil 22 via contactless transmission. That is, when the magnetic fields generated in the transmitting coil 22 and the main receiving coil 102 link with the sub-receiving coil 103, a high-frequency current flows through the sub-receiving coil 103, which fluctuates with the frequency of the high-frequency current flowing through the transmitting coil 22 and the main receiving coil 102. The high-frequency current flowing through the sub-receiving coil 103 is supplied to the regulator 360.

[0058] The regulator 360 is a circuit that takes a high-frequency current (alternating current) as input and outputs a direct current (DC) at a predetermined voltage. More specifically, the regulator 360 rectifies the input high-frequency current (alternating current) into a DC current, then smooths it to suppress voltage fluctuations in the DC current, stabilizes the voltage, and outputs a DC current at a predetermined voltage. The output voltage of the regulator 360 is, for example, approximately the same voltage as the rated voltage of the low-voltage storage battery 302.

[0059] The regulator 360 is connected to the drive circuit 353 and the power receiving control device 231. This ensures that even if the power supply from the low-voltage battery 302 to the drive circuit 353 is interrupted, or if the power supply from the low-voltage battery 302 to the power receiving control device 231 is interrupted, the sub-power receiving coil 103 can secure operating power for the drive circuit 353 and the power receiving control device 231. This allows the first and second lower arm switches QL1 and QL2 to be switched on, thereby suppressing the occurrence of overvoltage abnormalities.

[0060] <Modification of the First Embodiment> The function of the drive circuit 353 may be incorporated into the power receiving device 231. In this case, the drive circuit 353 does not need to be provided in the power receiving device 100 separately from the power receiving device 231.

[0061] <Second Embodiment> The second embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, as shown in Figure 6, the power receiving device 100 is equipped with multiple systems (two systems are shown as examples) of a main power receiving coil, a power receiving side resonant circuit, a filter circuit, and a rectifier circuit.

[0062] The power receiving device 100 includes a first power receiving side resonant circuit 140A, a first filter circuit 182A, and a first rectifier circuit 200A. The power receiving device 100 also includes a second power receiving side resonant circuit 140B, a second filter circuit 182B, and a second rectifier circuit 200B. The configurations of each resonant circuit 140A, 140B, each filter circuit 182A, 182B, and each rectifier circuit 200A, 200B are the same as those of the power receiving side resonant circuit 140, filter circuit 182, and rectifier circuit 200 in the first embodiment.

[0063] The power receiving coil unit 101, which constitutes the power receiving device 100, includes a first main power receiving coil 110 and a second main power receiving coil 130. The first main power receiving coil 110 is connected to a first power receiving resonant circuit 140A, and the second main power receiving coil 130 is connected to a second power receiving resonant circuit 140B.

[0064] As shown in Figure 7, the power receiving device 100 includes a first drive circuit 354A and a second drive circuit 354B. A low-voltage battery 302 is connected to each drive circuit 354A and 354B via a second electrical path 351. Power is supplied from the low-voltage battery 302 to each drive circuit 354A and 354B via the second electrical path 351, enabling each drive circuit 354A and 354B to operate.

[0065] If the first drive circuit 354A determines, for example, that a short-circuit command has been input from the power receiving control device 231, it performs a short-circuit operation by turning on only the first and second lower arm switches QL1 and QL2 among the first and second upper and lower arm switches QH1, QL1, QH2, and QL2 that constitute the first rectifier circuit 200A.

[0066] If the second drive circuit 354B determines, for example, that a short-circuit command has been input from the power receiving control device 231, it performs a short-circuit operation by turning on only the first and second lower arm switches QL1 and QL2 among the first and second upper and lower arm switches QH1, QL1, QH2, and QL2 that constitute the second rectifier circuit 200B.

[0067] The regulator 360 is connected to the first drive circuit 354A and the second drive circuit 354B. The sub-power receiving coil 103 that supplies power to the regulator 360 is magnetically coupled to the first main power receiving coil 110 and the second main power receiving coil 130.

[0068] As a result, even if the relative positional relationship of each main receiving coil 110, 130 with respect to the ground-side transmitting coil 22 changes, a large coupling coefficient can be maintained between any of the main receiving coils and the transmitting coil 22. Consequently, even if the above relative positional relationship changes, power can be accurately supplied from the sub-receiving coil 103 to each drive circuit 354A, 354B and the receiving-side control device 231.

[0069] Figure 8 shows a comparative example different from this embodiment. In the comparative example, auxiliary coils 370A and 370B are provided as backup power sources for each drive circuit 354A and 354B, magnetically coupled to the reactors of each filter circuit 182A and 182B. The power received by each auxiliary coil 370A and 370B is supplied to each drive circuit 354A and 354B. In the comparative example, the same number of auxiliary coils as the number of filter circuits are required. Furthermore, the comparative example cannot be applied to power receiving devices that do not have filter circuits.

[0070] Next, specific examples of the sub-receiving coil 103, the first main receiving coil 110, and the second main receiving coil 130 will be described using Figures 9 and 10. Figures 9 and 10 are plan views of each coil. Figure 10 is a plan view of each coil as seen from the transmission coil 22 side.

[0071] The first main power receiving coil 110 is a DD coil having a first coil 111 and a second coil 112 which is arranged adjacent to the first coil 111 and whose winding direction is opposite to that of the first coil 111. The first coil 111 and the second coil 112 form an annular shape. The direction in which the first coil 111 and the second coil 112 are aligned is the direction of vehicle travel. In Figures 9 and 10, the first main power receiving coil 110 is marked with dot hatching.

[0072] The second main power receiving coil 130 is positioned across the central axis Lα that extends to the boundary between the first coil 111 and the second coil 112. The central axis Lα is an axis that extends in a direction perpendicular to the direction of vehicle travel and the vertical direction.

[0073] The power transmission coil 22 is a DD coil comprising a first power transmission coil 22A and a second power transmission coil 22B that form an annular shape. The second power transmission coil 22B is positioned adjacent to the first power transmission coil 22A and has a winding direction opposite to that of the first power transmission coil 22A.

[0074] The sub-power receiving coil 103 has an asymmetrical shape with respect to the central axis Lα. In the example shown in Figure 9, the sub-power receiving coil 103 is positioned inside the peripheral edge of the first coil 111. Note that the sub-power receiving coil 103 is not shown in Figure 10.

[0075] In a plan view of each main power receiving coil 110, 130 and sub-power receiving coil 103, the area S1 of the region in the sub-power receiving coil 103 where the magnetic flux in the first direction links is not equal to the area S2 of the region where the magnetic flux in the second direction opposite to the first direction links. In the example shown in Figure 9, the area in the sub-power receiving coil 103 where the magnetic flux in the second direction links is 0. This makes it possible to increase the coupling coefficient between each main power receiving coil 110, 130 and the sub-power receiving coil 103.

[0076] Furthermore, S1 and S2 being equivalent includes both "the case where S1 = S2" and "the case where the difference between S1 and S2 is 10% or less of the larger of S1 and S2, or 5% or less."

[0077] Figure 11 shows the calculation results of the relationship L1 between the displacement of the first main receiving coil 110 relative to the transmitting coil 22 and the coupling coefficient between the transmitting coil 22 and the first main receiving coil 110. Also in Figure 11, the calculation results of the relationship L2 between the displacement of the second main receiving coil 130 relative to the transmitting coil 22 and the coupling coefficient between the transmitting coil 22 and the second main receiving coil 130 are shown.

[0078] In the misalignment region where the coupling coefficient between the transmission coil 22 and the first main receiving coil 110 is relatively small, the coupling coefficient between the transmission coil 22 and the second main receiving coil 130 is relatively large. In other words, even if the relative positional relationship of each main receiving coil 110, 130 with respect to the transmission coil 22 changes, a large coupling coefficient can be maintained between any of the main receiving coils and the transmission coil 22.

[0079] In contrast, as shown in the sub-receiving coil 106 of Comparative Example 1 in Figure 12, when S1 and S2 are equivalent, the coupling coefficient between each main receiving coil 110, 130 and the sub-receiving coil 106 becomes close to zero. Also, although the sub-receiving coil 107 of Comparative Example 2 in Figure 13 has an asymmetrical shape with respect to the central axis Lα, S1 and S2 are equivalent, so the coupling coefficient becomes close to zero.

[0080] <Modification of the second embodiment> The shape of the sub-power receiving coil is not limited to the shape shown in Figure 9. As long as it has an asymmetric shape with respect to the central axis Lα, it may be, for example, the sub-power receiving coil 104 shown in Figure 14 or the sub-power receiving coil 105 shown in Figure 15.

[0081] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the main power receiving coil has a plurality of annular coils (specifically, Q coils) arranged in a predetermined direction (vehicle travel direction), as shown in Figure 16. In the example shown in Figure 16, four annular coils 401, 402, 403, and 404 are arranged in a line. In a plan view of each annular coil 401 to 404, the winding direction of the annular coils 401 to 404 is the same.

[0082] Each of the annular coils 401 to 404 is connected to a power-receiving resonant circuit. Therefore, four systems of power-receiving resonant circuits, filter circuits, and rectifier circuits are provided.

[0083] The sub-power receiving coil 410, shown by the dashed line in Figure 16, extends in the direction of vehicle travel and is positioned to overlap each of the annular coils 401 to 404 in a plan view. This allows for a large coupling coefficient between each of the annular coils 401 to 404 and the sub-power receiving coil 410.

[0084] As shown in Figure 17, in each of the annular coils 401 to 404, the areas S1, S2, S3, and S4 of the region enclosed by the peripheral edge of the annular coil and the peripheral edge of the sub-receiving coil 410 are equivalent. This makes it possible to suppress changes in the power received by the sub-receiving coil 410 in response to changes in the relative position of the sub-receiving coil 410 with respect to the power transmitting coil 22.

[0085] <Modification of the Third Embodiment> The shape of the sub-power receiving coil is not limited to the shape shown in Figures 16 and 17. As long as it is arranged to overlap each of the annular coils 401 to 404 in a plan view, it may be, for example, the sub-power receiving coil 411 shown in Figure 18 or the sub-power receiving coil 412 shown in Figure 19. Even in this case, the coupling coefficient between each of the annular coils 401 to 404 and the sub-power receiving coils 411 and 412 can be increased.

[0086] <Fourth Embodiment> The fourth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the main power receiving coil has a plurality of annular coils (specifically, Q coils) arranged in a predetermined direction (vehicle travel direction), as shown in Figure 20. In the example shown in Figure 20, two annular coils, the first annular coil 501 and the second annular coil 502, are arranged side by side. The winding direction of each annular coil 501 and 502 is the same.

[0087] Each of the annular coils 501 and 502 is connected to a power-receiving resonant circuit. Therefore, two systems of power-receiving resonant circuits, filter circuits, and rectifier circuits are provided.

[0088] Each annular coil 501, 502 is arranged so as to overlap each other in a plan view. In Figure 20, the overlapping portion 503 in a plan view, surrounded by the periphery of each annular coil 501, 502, is hatched. The sub-receiving coil 510 is positioned such that the area surrounded by the periphery of the sub-receiving coil 510 is included in the overlapping portion 503. This makes it possible to suppress changes in the power received by the sub-receiving coil 510 in response to changes in the relative position of the sub-receiving coil 510 with respect to the transmission coil 22.

[0089] <Other Embodiments> The above embodiments may be modified and implemented as follows.

[0090] As shown in Figure 21, the sub-power receiving coil 610 may be arranged so as to surround all of the annular coils 601, 602, and 603 that constitute the main power receiving coil (three are shown as examples in the figure). Each of the annular coils 601 to 603 is, for example, a Q coil and is arranged in a line in the direction of vehicle travel.

[0091] The short-circuit switch is not limited to a switch provided in the rectifier circuit 200, but may be a switch provided separately from the switch in the rectifier circuit 200. Figure 22 shows a short-circuit switch 400 connecting the first resonant capacitor 141 and the second resonant capacitor 142.

[0092] • Various antennas, not limited to communication coils, can be used as the receiving and transmitting communication antennas. For example, the communication antenna can be a dipole antenna or a monopole antenna.

[0093] The vehicle identification information used in the processing of each of the above embodiments is not limited to vehicle ID information, but may also include, for example, a token or the vehicle user's credit card information.

[0094] The contactless power supply system may have a first function of contactlessly supplying power from the ground-side device to the vehicle-side device, as well as a second function of contactlessly supplying power from the vehicle-side device to the ground-side device. In this case, the vehicle-side power receiving device 100 has a power transmission function in addition to a power receiving function. The ground-side power transmission device 20 has a power receiving function in addition to a power transmission function. The second function will be explained below using Figure 3 as an example.

[0095] The power receiving control device 231 applies a high-frequency AC voltage to the main power receiving coil 102 by switching control of the rectifier circuit 200. As a result, a high-frequency current flows through the main power receiving coil 102, and a magnetic field for power transmission is generated in the main power receiving coil 102.

[0096] When the magnetic field generated in the main receiving coil 102 links with the transmitting coil 22, a high-frequency current flows through the transmitting coil 22, fluctuating at the frequency of the high-frequency current flowing through the main receiving coil 102. The high-frequency current flowing through the transmitting coil 22 is supplied to the AC power supply 15 via the transmitting-side resonant circuit 30, filter circuit 52, inverter 60, and PFC circuit 61. In this case, the transmitting-side control device 71 switches the inverter 60 and the PFC circuit 61.

[0097] In a non-contact power supply system having a second function, for example, the power transmission device 20 may be equipped with a transmitter that supplies a power supply request signal to the power transmission side communication coil 40. The power receiving device 100 may be equipped with a receiver that receives the power supply request signal received by the power receiving side communication coil 170 and inputs it to the power receiving side control device 231.

[0098] - The contactless power supply system may have a function to supply power from the vehicle-side equipment to the ground-side equipment, instead of a function to supply power from the ground-side equipment to the vehicle-side equipment.

[0099] The vehicle on which the power receiving device 100 is mounted is not limited to a vehicle traveling on a road RS, but may also be, for example, an AGV (Automated Guided Vehicle) or a mobile robot. In this case, the power transmission coil unit 21 may not be buried in the road RS, but may be installed on a sidewalk adjacent to the road RS, a parking lot, or on a route along which the AGV travels.

[0100] In this disclosure or claims, the term "processor" means one or more hardware processors configured to execute processing defined by computer program code (i.e., one or more instructions of a computer program) contained in a computer program by reading the computer program code each time. In other words, a "processor" is a hardware device that executes one or more programmed processes. Therefore, computer program code can also be said to be software that can define the processing of the processor according to its content. A "processor" can be a general-purpose or specific-purpose processor, and may be, but is not limited to, a CPU, microprocessor, GPU, and DFP (Data Flow Processor).

[0101] In this disclosure or claims, the term “memory” means one or more hardware memories that are non-transitional tangible recording media configured to record computer program code and / or data in a manner accessible from a processor. “Memory” can be implemented by memory technology such as SRAM, SDRAM, non-volatile / flash type memory, or other types of memory. The computer program code that constitutes the program is recorded in memory and executed by a processor, thereby enabling the processor to perform the various functions described above.

[0102] In this disclosure or claims, the term “circuit” refers to one or more logic circuits as hardware, configured to perform specific processing defined by a pre-designed circuit configuration. In other words (and, in contrast to “processor”), “circuit” in this disclosure or claims refers to a hardware device that performs specific processing based on a circuit configuration, rather than processing defined by software such as the computer program code described above. For example, “circuit” may include custom ICs such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) designed with Hardware Description Language (HDL). That is, “circuit” in this disclosure or claims includes all hardware circuits except for the processors described above that perform processing by reading computer program code.

[0103] In this disclosure or claims, the expression "at least one of the circuit and processor" should be interpreted as disjunctive (logical OR) and not as "at least one circuit and at least one processor." Therefore, in this disclosure or claims, "at least one of the circuit and processor causes the device to perform functions" includes cases where the circuit alone causes the device to perform all functions. Also, "at least one of the circuit and processor causes the device to perform functions" includes cases where the processor alone causes the device to perform all functions. Furthermore, "at least one of the circuit and processor causes the device to perform functions" includes cases where the circuit causes the device to perform some functions and the processor causes the device to perform the remaining functions. In the last example, for example, if the device performs functions A to C, functions A and B may be implemented by the circuit, and the remaining function C may be implemented by the processor.

[0104] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

Claims

1. A power receiving device (100) having main power receiving coils (102, 110, 130, 401-404, 501, 502, 601-603) and receiving non-contact power from a power transmission coil (22) of a power transmission device (20), comprising: sub-power receiving coils (103-105, 410-412, 510, 610) which are separate coils from the main power receiving coils and are magnetically coupled to the main power receiving coils; short-circuit switches (QL1, QL2, 400); and drive circuits (353, 354A, 354B) which are connected to a power storage unit (302) via an electrical path (351) and control the short-circuit switches, wherein when the short-circuit switches are turned on, they form a closed circuit including the main power receiving coils and the short-circuit switches; and the drive circuits are configured to be operable when power is supplied. A power receiving device to which the power received by the sub-power receiving coil is supplied to the drive circuit.

2. The power receiving device according to claim 1, wherein the main power receiving coils (110, 130) are a plurality, and the sub-power receiving coils (103 to 105) are magnetically coupled to the plurality of main power receiving coils.

3. The power receiving device according to claim 2, wherein the main power receiving coil comprises a first coil (111) and a second coil (112) arranged adjacent to the first coil and having a winding direction opposite to that of the first coil, the sub-power receiving coil has an asymmetric shape with respect to a central axis extending to the boundary portion of the first coil and the second coil, and in a plan view of the first coil, the second coil and the sub-power receiving coil, the area of ​​the region in the sub-power receiving coil where magnetic flux in a first direction links is not equal to the area of ​​the region where magnetic flux in a second direction opposite to the first direction links.

4. The power receiving device according to claim 2, wherein the main power receiving coil comprises a plurality of annular coils (401 to 404) arranged in a predetermined direction, and the sub-power receiving coils (410 to 412) extend in the predetermined direction and are arranged to overlap each of the annular coils in a plan view.

5. The power receiving device according to claim 4, wherein in each of the annular coils, the area of ​​the region enclosed by the peripheral edge of the annular coil and the peripheral edge of the sub-power receiving coil (410) is equal.

6. The power receiving device according to claim 2, wherein the main power receiving coil is provided with a plurality of annular coils (501, 502), each annular coil is arranged to overlap each other in a plan view, and the sub-power receiving coil is arranged such that the area surrounded by the periphery of the sub-power receiving coil (510) is included in the overlapping portion (503) in a plan view of the area surrounded by the periphery of each annular coil.

7. A power receiving device according to any one of claims 1 to 6, comprising a DC-AC conversion circuit (200, 200A, 200B) that converts the AC current supplied from the main power receiving coil into a DC current and supplies it to a powered device (300), wherein the short-circuit switches (QL1, QL2) are switches of the DC-AC conversion circuit.

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