Wireless power transfer system, program, control method for wireless power transfer system, power transmitter and control method for power transmitter

Abstract

The wireless power transfer system includes a power receiver (100) mounted on a vehicle and a power transmitter (20). The power transmitter includes a power-transmitter control unit (70) that calculates an intensity of a power supply request signal based on a signal received by a power-transmitter communication coil (40). The power-transmitter control unit determines that an abnormality has occurred in communication of the power transmitter on condition that it determines that the calculated intensity is outside an expected intensity range.

Description

WIRELESS POWER TRANSFER SYSTEM, PROGRAM, CONTROL METHOD FOR WIRELESS POWER TRANSFER SYSTEM, POWER TRANSMITTER AND CONTROL METHOD FOR POWER TRANSMITTERCross Reference

[0001] This application is based on Japanese Patent Application No. 2024-208017 filed on November 29, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a wireless power transfer system, a program, a control method for a wireless power transfer system, a power transmitter, and a control method for a power transmitter.

[0003] Patent Literature 1 discloses a system for executing wireless power transfer from a ground-based power transmitter to a power receiver installed in an electric vehicle. The power transmitter includes a power transmitter coil and a controller that energizes the power transmitter coil. The power receiver includes a power receiver coil that is supplied with power wirelessly from the power transmitter coil.

[0004] The power transmitter and the power receiver include communication coils for narrow area wireless communication. The power receiver supplies a vehicle-side signal including a power supply request signal to the communication coil of the power receiver. The power transmitter determines whether there is a power supply request based on a received signal of the communication coil of the power transmitter. When the power transmitter determines that there is a power supply request, the power transmitter energizes the power transmitter coil.

[0005] JP 2024-008088 A

[0006] If an abnormality occurs in the communication of the power transmitter, the power supply request signal may not be properly received from the power receiver. Thus, there is a demand for technology that can determine whether an abnormality has occurred. Such a technique is also desired when the power transmitter is a vehicle-side device and the power receiver is a ground-side device.

[0007] It is a main objective of the present disclosure is to provide a wireless power transfer system, a program, a control method for a wireless power transfer system, a power transmitter, and a control method for a power transmitter, which are capable of determining whether an abnormality has occurred in communication of a power transmitter.

[0008] According to an aspect of the present disclosure, a wireless power transfer system includes a ground-side device and a vehicle-side device. One of the ground-side device and the vehicle-side device is a power transmitter having a power transmitting antenna. The other of the ground-side device and the vehicle-side device is a power receiver having a power receiving antenna. The power receiver is configured to transmit a power supply request signal for a power supply request to the power transmitter. The power transmitter is configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal. The power transmitter includes a power-transmitter communication antenna configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna provided in the power receiver. The wireless power transfer system further includes a diagnostic unit configured to execute a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

[0009] Accordingly, it can be determined whether a communication abnormality has occurred in the power transmitter.

[0010] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.FIG. 1 is an overall configuration diagram of a wireless power transfer system according to a first embodiment.FIG. 2 is an overall configuration diagram of the wireless power transfer system.FIG. 3 is a diagram illustrating a power transmitter and a power receiver.FIG. 4 is a diagram illustrating a configuration of wide area wireless communication between the power transmitter and a vehicle.FIG. 5 is a diagram illustrating a power-receiver control unit and its peripheral configuration.FIG. 6 is a diagram illustrating a power-transmitter control unit and its peripheral configuration.FIG. 7 is a flowchart illustrating a process executed by the power transmitter.FIG. 8 is a flowchart illustrating a diagnostic process executed by a server.FIG. 9 is a diagram illustrating a specific example of a diagnostic method.FIG. 10 is a diagram illustrating a specific example of a diagnostic method.FIG. 11 is a diagram illustrating a specific example of a diagnostic method.FIG. 12 is a flowchart illustrating a diagnostic process according to a second embodiment.FIG. 13 is a flowchart illustrating a diagnostic process according to a third embodiment.FIG. 14 is a flowchart illustrating a diagnostic process according to a fourth embodiment.FIG. 15 is an overall configuration diagram of a wireless power transfer system according to a fifth embodiment.FIG. 16 is a diagram illustrating a specific example of a diagnostic method.FIG. 17 is a diagram illustrating a deviation degree of a vehicle according to a sixth embodiment.FIG. 18 is a diagram illustrating a specific example of a diagnostic method.FIG. 19 is a diagram illustrating a specific example of a diagnostic method.

[0011] Multiple embodiments will be described with reference to the drawings. In the embodiments, parts that functionally and / or structurally correspond to or are associated with each other may be assigned the same reference numeral, or reference numerals different in digit in the hundreds or higher place. The corresponding and / or associated parts may refer to the explanation in the other embodiments.

[0012] First Embodiment A first embodiment of a wireless power transfer system of the present disclosure will be described below with reference to the drawings.

[0013] First, an overall configuration of the wireless power transfer system will be described. As shown in FIGS. 1, 2, and 3, the wireless power transfer system 10 includes a power transmitter 20 and a power receiver 100. The power receiver 100 is mounted on a vehicle 11 as a moving object that travels on a road RS, and is a vehicle-side device. The vehicle 11 is, for example, an electric automobile or a hybrid vehicle. The power is supplied from the power transmitter 20 to the power receiver 100 while the vehicle 11 is travelling or stopped. The wireless power transfer system 10 executes wireless power transfer from the power transmitter 20 to the power receiver 100 through magnetic field resonance coupling (magnetic field resonance). The wireless power transfer system 10 is also referred to as a dynamic wireless power transfer (D-WPT) system.

[0014] The power transmitter 20 is a ground-side device and has a power-transmitter coil unit 21 and a power-transmitter power supply unit 51 that supplies power to the power-transmitter coil unit 21. The power transmitter 20 is, for example, a stationary device. The power-transmitter coil unit 21 is installed (for example, buried) in the road RS, a parking lot, or the like. The power-transmitter power supply unit 51 is installed, for example, on the side of the road RS. The power-transmitter coil unit 21 is connected to the power-transmitter power supply unit 51. The power-transmitter power supply unit 51 is connected to an AC power source 15 and supplies AC (alternating-current) power from the AC power source 15 to the power-transmitter coil unit 21. The AC power source 15 is, for example, a commercial power source. Multiple power-transmitter coil units 21 are arranged along the lanes of the road RS.

[0015] FIG. 2 shows an example in which one power-transmitter power supply unit 51 is connected to one power-transmitter coil unit 21. The power-transmitter coil units 21 are arranged at predetermined intervals in a vehicle travel direction. The power-transmitter coil units 21 are installed such that the interval between the center positions of the power-transmitter coil units 21 in the vehicle travel direction is, for example, about 1.5 to 2 m, and the separation interval between the power-transmitter coil units 21 is, for example, about 0.5 to 0.8 m. In FIG. 2, the power-transmitter coil units 21 are disposed at separation intervals D1.

[0016] The power-transmitter power supply unit 51 includes a PFC (Power Factor Correction) 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 source 15. The PFC circuit 61 includes switching elements (e.g., IGBTs or MOSFETs) that are switched and controlled to convert the input AC power to DC (direct current) power and improve a power factor of the AC power input from the AC power source 15. IGBT is an abbreviation of Insulated Gate Bipolar Transistor. MOSFET is an abbreviation of Metal-Oxide-Semiconductor Field-Effect Transistor.

[0017] The inverter 60 is connected to the PFC circuit 61. The inverter 60 includes switching elements (e.g., IGBTs or MOSFETs) that are switched and controlled to convert the DC power input from the PFC circuit 61 to AC power.

[0018] The filter circuit 52 removes noise contained in the AC current input from the inverter 60 and supplies the AC current from which noise has been removed to the power-transmitter coil unit 21. The filter circuit 52 is, for example, an LC filter that includes a coil and a capacitor. Circuits having various configurations can be used as the filter circuit 52, and, for example, a T-type filter circuit is used as the filter circuit 52.

[0019] The power-transmitter coil unit 21 includes a power transmitter coil 22 (corresponding to power transmitting antenna), a power-transmitter resonant circuit 30, and a power-transmitter communication coil 40. The power-transmitter resonant circuit 30 supplies the AC power supplied by the filter circuit 52 to the power transmitter coil 22. The power-transmitter resonant circuit 30 can employ various well-known resonant circuits such as a circuit including a resonant capacitor.

[0020] The power receiver 100 includes a power-receiver coil unit 101 and a power-receiver power supply unit 181. The power-receiver coil unit 101 includes a power receiver coil 102 (corresponding to a "power receiving antenna"). The power-receiver coil unit 101 is located at the bottom of the vehicle body of the vehicle 11. The power-receiver coil unit 101 is located at the bottom of the vehicle body to face the ground surface. When the vehicle 11 travels on the road RS where the power transmitter coil 22 is buried, the power transmitter coil 22 on the ground side and the power receiver coil 102 of the vehicle 11 face each other in the vertical direction.

[0021] The power receiver 100 includes a power-receiver resonant circuit 140. The power receiver coil 102 is connected to the power-receiver resonant circuit 140. The power receiver coil 102 is supplied with power from the power transmitter coil 22. The power receiver coil 102 supplies the received power to the power-receiver resonant circuit 140. The power-receiver resonant circuit 140 can employ various well-known resonant circuits such as a circuit including a resonant capacitor.

[0022] The power receiver 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-receiver resonant circuit 140 and supplies the AC current from which noise has been removed to the rectifier circuit 200. The filter circuit 182 of the present embodiment is, for example, an LC filter that includes reactor and a capacitor.

[0023] The rectifier circuit 200 converts the input AC current into a DC current and outputs the DC current. The rectifier circuit 200 is, for example, a full-bridge circuit including semiconductor switching elements, or a diode rectifier circuit. A first end of the smoothing capacitor 210 is connected to a high potential side output terminal of the rectifier circuit 200. A second end of the smoothing capacitor 210 is connected to a low potential side output terminal of the rectifier circuit 200. The rectifier circuit 200 is also referred to as an ERB (Electronic Rectification Box).

[0024] The vehicle 11 includes a high potential main switch 301H, a low potential main switch 301L, and a high-voltage storage battery 300 as a power storage unit. The high potential main switch 301H and the low potential main switch 301L are, for example, relays (specifically, mechanical relays). The high potential side output terminal of the rectifier circuit 200 is connected to a positive terminal of the high-voltage storage battery 300 via the high potential main switch 301H. The low potential side output terminal of the rectifier circuit 200 is connected to a negative terminal of the high-voltage storage battery 300 via the low potential main switch 301L. The high-voltage storage battery 300 is a secondary battery that can be charged and discharged and has a rated voltage of several hundred volts, for example. The high-voltage storage battery 300 is, for example, a lithium-ion storage battery or a nickel-metal hydride storage battery.

[0025] The vehicle 11 includes a travelling inverter 310 and a rotary electric machine 320. The travelling inverter 310 is a 3-phase inverter and is connected to the high-voltage storage battery 300 via the high potential main switch 301H and the low potential main switch 301L. The armature windings of the rotary electric machine 320 are connected to the upper and lower arm switches that constitute the travelling inverter 310. By switching control of the upper and lower arm switches of the travelling inverter 310 while the high potential main switch 301H and the low potential main switch 301L are turned on, the travelling inverter 310 converts the DC power supplied from the high-voltage storage battery 300 into AC power and supplies it to the armature winding. This causes the rotor of the rotary electric machine 320 to rotate, and the rotational power of the rotor rotates wheels 12 (drive wheels) of the vehicle 11. As a result, the vehicle 11 travels.

[0026] As shown in FIG. 3, the power-transmitter power supply unit 51, which constitutes the power transmitter 20, includes a power-transmitter control unit 70. The power-transmitter control unit 70 includes a power-transmitter controller 71. The power-transmitter controller 71 is an electronic control unit (ECU) that executes various controls of the power transmitters 20 and includes a processor as hardware, a storage unit, and a communication bus connecting the processor and storage unit.

[0027] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the power-transmitter controller 71. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory includes, for example, RAM and ROM. The storage is a storage device that stores various programs and data to be read and executed by the processor and is a non-transitory tangible storage medium. The storage includes, for example, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0028] The power-receiver power supply unit 181, which constitutes the power receiver 100, includes a power-receiver controller 231. The power-receiver controller 231 is an ECU that executes various controls of the power receiver 100, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and storage unit.

[0029] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the power-receiver controller 231. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory includes, for example, RAM and ROM. The storage is a storage device that stores various programs and data to be read and executed by the processor and is a non-transitory tangible storage medium. The storage includes, for example, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0030] The power-transmitter controller 71 executes a switching control of the PFC circuit 61 and a switching control of the inverter 60. Through the switching control of the inverter 60, a high-frequency AC voltage is applied to the power transmitter coil 22. This causes a high-frequency current to flow in the power transmitter coils 22 and a magnetic field for power transmission is generated in the power transmitter coils 22.

[0031] In this embodiment, the power-transmitter controller 71 switches and controls the inverter 60 so that the frequency of the high-frequency voltage applied to the power transmitter coil 22 is becomes a first specified frequency between 10 kHz and 100 GHz, specifically, 85 kHz. The resonant frequencies of the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 are set at the same frequency or close to the first specified frequency.

[0032] When the magnetic field generated in the power transmitter coil 22 links with the power receiver coil 102 of the vehicle 11, a high-frequency current flows in the power receiver coil 102, varying with the frequency of the high-frequency current flowing in the power transmitter coil 22. The high-frequency current flowing in the power receiver coil 102 is supplied to the rectifier circuit 200 through the power-receiver resonant circuit 140 and the filter circuit 182. The rectifier circuit 200 converts the supplied AC current into a DC current and outputs the DC current. While the high potential main switch 301H and the low potential 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 travelling inverter 310.

[0033] The vehicle 11 includes a low-voltage storage battery 302. The rated voltage of the low-voltage storage battery 302 is lower than the rated voltage of the high-voltage storage battery 300. The low-voltage storage battery 302 is, for example, a lead-acid battery. The power supplied from the low-voltage storage battery 302 to the power-receiver controller 231 enables the power-receiver controller 231 to operate.

[0034] The power receiver 100 and the power transmitter 20 each have a configuration for communication between the power receiver 100 and the power transmitter 20. In detail, the power-receiver coil unit 101, which constitutes the power receiver 100, includes a power-receiver communication coil 170 (corresponding to a power-receiver communication antenna). A power-receiver control unit 230 includes a signal transmitter 240.

[0035] The power-transmitter coil unit 21, which constitutes the power transmitter 20, includes a power-transmitter communication coil 40 (corresponding to a power-transmitter communication antenna). The power-transmitter control unit 70 includes a signal receiver 80. The power-receiver communication coil 170 and the power-transmitter communication coil 40 are communication coils for narrow area wireless communication. Narrow area wireless communications are those with a communication distance of less than 10 meters (e.g., a maximum of 3 meters). Narrow area wireless communication is a communication with a shorter communication distance than wide area wireless communication.

[0036] Various short-range wireless communications can be used as the narrow area wireless communication. For example, communications compliant with any communication standards established by IEEE, ISO, and IEC can be used. Specifically, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), RFID (Radio Frequency Identification), or DSRC (Dedicated Short Range Communication) can used as the narrow area wireless communication.

[0037] The signal transmitter 240 is connected to the power-receiver controller 231. The signal transmitter 240 is connected to the power-receiver communication coil 170. The power-receiver controller 231 controls the signal transmitter 240 to supply a power supply request signal COMM to the power-receiver communication coil 170. The power supply request signal COMM is a signal requesting the power transmitter coil 22 near the vehicle 11 to transmit power to the power receiver coil 102.

[0038] The power-receiver control unit 230 includes a vehicle-side signal, which contains the power supply request signal COMM, into one frame and supplies the frame to the power-receiver communication coil 170. In this embodiment, the power supply request signal COMM includes ID information of the vehicle 11 and a requested power Weq that is a requested value of power to be supplied to the vehicle 11. When the vehicle-side signal is supplied to the power-receiver communication coil 170, a high-frequency voltage is applied from the signal transmitter 240 to the power-receiver communication coil 170. Consequently, a high-frequency current flows in the power-receiver communication coil 170, and a magnetic field for information communication is generated in the power-receiver communication coil 170.

[0039] When the power-receiver coil unit 101 of the vehicle 11 approaches the power-transmitter coil unit 21 on the ground side, the magnetic field generated by the power-receiver communication coil 170 links to the power-transmitter communication coil 40, and a high-frequency current flows through the power-transmitter communication coil 40. This high-frequency current is input to the signal receiver 80. The signal receiver 80 recognizes the presence or absence of a power supply request and ID information based on the input signal from the power-transmitter communication coil 40. The signal receiver 80 also acquires the requested power Weq for the vehicle 11 with the recognized ID information, based on the signal from the power-transmitter communication coil 40. The information recognized by the signal receiver 80 and the requested power Weq are input to the power-transmitter controller 71.

[0040] In this embodiment, the power-receiver controller 231 controls the signal transmitter 240 so that the frequency of the high-frequency voltage applied to the power-receiver communication coil 170 becomes a second specified frequency between 10 kHz and 100 GHz. In this embodiment, the second specified frequency is a frequency that deviates from the first specified frequency above, specifically a frequency higher than the first specified frequency (e.g., 13.56 MHz).

[0041] The power-transmitter controller 71 determines whether to energize the power transmitter coil 22 based on the input signal from the signal receiver 80. In detail, on condition that the power-transmitter controller 71 determines that there is a power supply request based on the input signal from the signal receiver 80, the power-transmitter controller 71 applies high-frequency voltage to the power transmitter coil 22 at the first specified frequency by performing the switching control of the inverter 60 and the PFC circuit 61. This results in a wireless power transfer from the power transmitter coil 22 to the power receiver coil 102.

[0042] The power transmitter 20 includes a power-transmitter voltage sensor 91 and a power-transmitter current sensor 92. The power-transmitter voltage sensor 91 detects voltages of various components of the power transmitter 20, for example, the voltage of the power transmitter coil 22. The power-transmitter current sensor 92 detects currents flowing through various components of the power transmitter 20, for example, the current flowing through the power transmitter coil 22. The detection values of each sensor 91, 92 are input to the power-transmitter controller 71.

[0043] FIG. 4 is a schematic diagram for explaining wide area wireless communication in the wireless power transfer system 10. In the wireless power transfer system 10, each vehicle 11 is capable of communicating with each power transmitter 20 via a communication network 16. The communication network 16 includes, for example, a WAN (Wide Area Network), which is a public communication network such as the Internet, a telephone communication network for a mobile phone, an information and communication network for ETC, and an information and communication network for a Vehicle Information and Communication System (VICS (registered trademark)). Wide area wireless communication is a communication with a longer communication distance than the narrow area wireless communication. Wide area wireless communication is communication with a communication distance of, for example, 10 meters to 10 kilometers. Examples of the wide area wireless communication include 3GPP (registered trademark), 4G, LTE, 5G, and WiMAX (registered trademark) developed by IEEE.

[0044] The vehicle 11 is equipped with a position sensor 330, a navigation device 331, and a communication unit 332. The position sensor 330 is a sensor that detects the current position of the vehicle, and is, for example, a GPS sensor. A storage unit (for example, storage) of the navigation device 331 stores map information including road information. The navigation device 331 receives information on the current position of the vehicle detected by the position sensor 330 and weather information. The power-transmitter control unit 70 of the power transmitter 20 includes a communication unit 90. The communication unit 332 of the vehicle 11 and the communication unit 90 of the power-transmitter control unit 70 perform wide area wireless communication via the communication network 16.

[0045] The wireless power transfer system 10 includes a server 400. The server 400 is, for example, a cloud server, and includes a server controller 401 and a communication unit 402. The server controller 401 is an electronic control unit (ECU) that executes various controls of the server 400 and includes a processor as hardware, a storage unit, and a communication bus connecting the processor and storage unit. The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the server controller 401. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory includes, for example, RAM and ROM. The storage is a storage device that stores various programs and data to be read and executed by the processor and is a non-transitory tangible storage medium. The storage includes, for example, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0046] The server controller 401 is connected to the communication unit 402. The server controller 401 performs wide area wireless communication with the communication unit 332 of the vehicle 11 and the communication unit 90 of the power-transmitter control unit 70 via the communication unit 402 and the communication network 16.

[0047] For example, the program information stored on the non-transitory tangible storage medium is installed in the storage units of the power-receiver controller 231, power-transmitter controller 71, and the server controller401. The storage medium is, for example, a USB memory, CD-ROM or DVD. In addition, program information transmitted over a communication network 16, such as OTA (Over The Air), is installed in the storage units.

[0048] Next, the signal transmitter 240 and its peripheral configuration will be described with reference to FIG. 5.

[0049] The signal transmitter 240 includes a generating circuit 241, and a power-receiver amplifier 242. The generating circuit 241 is connected to the power-receiver controller 231 and the power-receiver amplifier 242. The generating circuit 241 generates a vehicle-side signal, which is a high-frequency signal including a power supply request signal, based on a command from the power-receiver controller 231. The frequency of the vehicle-side signal is the second specified frequency. The power-receiver amplifier 242 amplifies the high-frequency signal generated by the generating circuit 241 and supplies the amplified signal to the power-receiver communication coil 170.

[0050] The power-receiver controller 231 instructs the generating circuit 241 to generate a vehicle-side signal. The high-frequency signal output from the generating circuit 241 is amplified by the power-receiver amplifier 242. The amplified signal is supplied to the power-receiver communication coil 170.

[0051] The signal receiver 80 and its peripheral configuration will be described with reference to FIG. 6.

[0052] The signal receiver 80 includes a power-transmitter amplifier 81, a detection circuit 82 and a determination circuit 83. The power-transmitter amplifier 81 amplifies the high-frequency signal (high frequency current or voltage signal) output from the power-transmitter communication coil 40 and supplies the amplified signal to the detection circuit 82. The high-frequency signal output from the power-transmitter communication coil 40 contains a frequency component that fluctuates at the second specified frequency.

[0053] The detection circuit 82 detects the high-frequency signal input from the power-transmitter amplifier 81, and calculates an intensity Intd which is an amplitude or effective value of the input high-frequency signal. The calculated intensity Intd is input to the determination circuit 83. The closer the power-receiver communication coil 170 of the vehicle 11 is to the power-transmitter communication coil 40 on the ground, the greater the intensity of the received signal from the power-transmitter communication coil 40 tends to be. The farther the power-receiver communication coil 170 is from the power-transmitter communication coil 40, the smaller the intensity of the received signal from the power-transmitter communication coil 40 tends to be. Taking this into consideration, the detection circuit 82 may, for example, calculate the intensity each time, and input a maximum intensity to the determination circuit 83. The maximum intensity is a maximum value of the calculated intensity during a period from when the calculated intensity starts to gradually increase, then gradually decreases, and until it starts to gradually increase again.

[0054] The determination circuit 83 determines whether there is a power supply request to the power transmitter coil 22 based on the input intensity Intd. Specifically, when determining that the intensity Intd exceeds a determination threshold Ijde, the determination circuit 83 determines that there is a power supply request. On the other hand, when determining that the intensity Intd is lower than the determination threshold Ijde, the determination circuit 83 determines that there is no power supply request. The determination result information of the determination circuit 83 is input to the power-transmitter controller 71. In this embodiment, the determination circuit 83 corresponds to a "determination unit."

[0055] When the power-transmitter controller 71 determines that there is no power supply request based on the input determination result information, the power-transmitter controller 71 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 kept off, and the power transmitter coil 22 is not energized.

[0056] On the other hand, on condition that it is determined that there is a power supply request based on the determination result information, the power-transmitter controller 71 applies a high frequency voltage to the power transmitter coil 22 by performing switching control of the PFC circuit 61 and the inverter 60 for a predetermined period of time. This causes a high-frequency current to flow through the power transmitter coil 22 for a predetermined period of time. In this case, wireless power transfer from the power transmitter coil 22 to the power receiver coil 102 that faces the power transmitter coil 22 in the vertical direction is performed. After energizing the power transmitter coil 22 for a predetermined period of time, the power-transmitter controller 71 does not energize the power transmitter coil 22 until it determines that there is a power supply request next time.

[0057] In addition, when the power-transmitter controller 71 determines that there is a power supply request, it actually performs a coupling determination process prior to executing the switching control of the inverter 60 and the PFC circuit 61 to determine whether the degree of magnetic coupling between the power receiver coil 102 and the power transmitter coil 22 is appropriate for power transmission. The power-transmitter controller 71 starts the above-described switching control on condition that the power-transmitter controller 71 has determined that the degree of magnetic coupling between the power receiver coil 102 and the power transmitter coil 22 is appropriate. As a result, the power transmitter coil 22 is energized while the power receiver coil 102 and the power transmitter coil 22 are in close proximity to each other.

[0058] FIG. 7 shows a flowchart of the process executed by each power-transmitter control unit 70.

[0059] In step S10, the detection circuit 82 determines whether a vehicle-side signal has been received by the power-transmitter communication coil 40 based on the output signal of the power-transmitter amplifier 81 (specifically, based on the signal received by the power-transmitter communication coil 40 and amplified by the power-transmitter amplifier 81).

[0060] When the detection circuit 82 determines that the signal has been received, the process proceeds to step S11, where the detection circuit 82 acquires the ID information of the vehicle based on the output signal of the power-transmitter amplifier 81.

[0061] In step S12, the detection circuit 82 calculates an intensity Intd of a vehicle-side signal (specifically, a power supply request signal) corresponding to each power-transmitter communication coil 40 based on the output signal of the power-transmitter amplifier 81. The detection circuit 82 inputs the calculated intensity Intd and the ID information to the power-transmitter controller 71.

[0062] In step S13, the power-transmitter controller 71 acquires the intensity Intd and the ID information corresponding to each power-transmitter communication coil 40 from the detection circuit 82. The power-transmitter controller 71 associates the acquired intensity Intd with the ID information of the vehicle, current time information, and identification information (hereinafter referred to as "coil identification information") that identifies the corresponding power-transmitter communication coil 40, and then transmits it to the server 400 via wide area wireless communication shown in FIG. 4. The coil identification information is, for example, ID information of the power-transmitter power supply unit 51.

[0063] An abnormality may occur in a communication function of the power transmitter 20. If an abnormality occurs, the power supply request signal transmitted from the power-receiver communication coil 170 of the power receiver 100 may not be properly received. Therefore, the server 400 as a diagnostic unit executes a process of diagnosing the communication function of the power transmitter 20. FIG. 8 is a flowchart illustrating a procedure of a diagnostic process.

[0064] In step S20, the server controller 401 of the server 400 determines whether the information transmitted from each power-transmitter controller 71 in the process of step S13 has been received.

[0065] When it is determined that the information has been received, the server controller 401 proceeds to step S21, and determines whether a communication abnormality has occurred in each power-transmitter communication coil 40 based on the information received by the process of step S20. In the present embodiment, the abnormality in communication includes an abnormality in any one of the power-transmitter communication coil 40, the power-transmitter amplifier 81, or the detection circuit 82. A specific example of the abnormality determination method will be described below.

[0066] First, the first specific example will be described with reference to FIG. 9. In FIG. 9, ○ indicates a power-transmitter communication coil 40 that has received a power supply request signal, and × indicates a power-transmitter communication coil 40 that has not received a power-supply request signal. When the server controller 401 determines that the intensity Intd received in step S20 is equal to or greater than a lower limit ILlimit and equal to or less than an upper limit IHlimit, the server controller 41 determines that a power supply request signal has been received (that is, ○). The range from the lower limit ILlimit to the upper limit IHlimit is an expected intensity range of the intensity Intd. The upper limit IHlimit and the lower limit ILlimit are values that are determined in advance by, for example, experiment or calculation. The above-mentioned determination threshold Ijde used to determine whether there is a power supply request is set to, for example, "ILlimit ≦ Ijde ≦ IHlimit".

[0067] As shown in FIG. 9 (a1), the server controller 401 determines that a communication abnormality has occurred in a downstream communication coil of two adjacent power-transmitter communication coils 40 in the vehicle travel direction when the server controller 401 determines that an upstream communication coil of the two adjacent power-transmitter communication coils 40 in the vehicle travel direction has received the power supply request signal and then the downstream communication coil has not received the power supply request signal based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd. The server controller 401 determines whether any two adjacent communication coils among the multiple power-transmitter communication coils 40 arranged along the road RS are in the relationship shown in (a1).

[0068] In step S20, the server controller 401 determines whether the above-described downstream communication coil has received the signal based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd. Wen it is determined that the signal has not been received, the server controller 401 determines that the downstream communication coil has not received a power supply request signal (i.e., ×).

[0069] The situation in which this determination is made is a case where it is determined in step S10 that the signal has not been received due to a communication abnormality in the power transmitter 20 although a vehicle-side signal is transmitted from the vehicle 11. In this case, the process of step S13 is not executed, and the intensity Intd is not transmitted to the server 400.

[0070] When the server controller 401 determines that the intensity Intd received in step S20 is lower than the lower limit ILlimit but is greater than zero, the server controller 41 determines that a power supply request signal has been received (that is, ○). The situation in which this determination is made is a case where a signal is received in step S10 of FIG. 7 and an intensity is transmitted in step S13, but the intensity of the output signal from the power-transmitter amplifier 81 does not become sufficiently large due to, for example, the deviation degree of the vehicle 11 in the vehicle width direction within a lane described in the sixth embodiment. In this situation, it may not be determined in general that a communication abnormality has occurred in the power-transmitter communication coil 40. On the other hand, when an upstream power-transmitter communication coil 40 has received a power supply request signal, but a downstream power-transmitter communication coil 40, which appears immediately after the upstream power-transmitter communication coil 40, suddenly become unable to receive a power supply request signal, there is a high possibility that a communication abnormality has occurred in the downstream power-transmitter communication coil 40.

[0071] As shown in FIG. 9 (a2), the server controller 401 determines that a communication abnormality has occurred in an upstream communication coil of two adjacent power-transmitter communication coils 40 in the vehicle travel direction when the server controller 401 determines that the upstream communication coil has not received the power supply request signal and then a downstream communication coil of the two adjacent power-transmitter communication coils 40 in the vehicle travel direction has received the power supply request signal based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd. The server controller 401 determines whether any two adjacent communication coils among the multiple power-transmitter communication coils 40 arranged along the road RS are in the relationship shown in (a2). The method of determining whether the mark is ○ or × in the case (a2) is the same as that in the case (a1).

[0072] Next, a second specific example will be described with reference to FIG. 10. The server controller 401 determines that a communication abnormality has occurred in a middle communication coil of three adjacent power-transmitter communication coils 40 in the vehicle travel direction when the server controller 401 determines that an upstream communication coil of the three adjacent power-transmitter communication coils 40 in the vehicle travel direction has received the power supply request signal, then the middle communication coil has not received the power supply request signal, and then a downstream communication coil of the three adjacent power-transmitter communication coils 40 in the vehicle travel direction has received the power supply request signal, based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd. The server controller 401 determines whether any three adjacent communication coils among the multiple power-transmitter communication coils 40 arranged along the road RS are in the relationship shown in FIG. 10. The method of determining whether the mark is ○ or × in the case of FIG. 10 is the same as that in the case of FIG. 9 (a1).

[0073] When the upstream and downstream power-transmitter communication coils 40 has received a power supply request signal, but the middle power-transmitter communication coil 40 has not received a power supply request signal, there is a high possibility that a communication abnormality has occurred in the middle power-transmitter communication coil 40. Therefore, according to the determination method shown in FIG. 10, it is possible to improve the accuracy of abnormality determination.

[0074] Next, a third specific example will be described with reference to FIG. 11. As shown in FIG. 11 (b1), the server controller 401 determines that a communication abnormality has occurred in a downstream communication coil of three adjacent power-transmitter communication coils 40 in the vehicle travel direction when the server controller 401 determines that an upstream and middle communication coils of the three adjacent power-transmitter communication coils 40 in the vehicle travel direction have successively received the power supply request signal, and then a downstream communication coil of the three adjacent power-transmitter communication coils 40 in the vehicle travel direction has not received the power supply request signal, based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd.

[0075] In addition, as shown in FIG. 11 (b2), the server controller 401 determines that a communication abnormality has occurred in an upstream communication coil of three adjacent power-transmitter communication coils 40 in the vehicle travel direction when the server controller 401 determines that the upstream communication coil has not received the power supply request signal and then a middle and downstream communication coil of the three adjacent power-transmitter communication coils 40 in the vehicle travel direction has successively received the power supply request signal, based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd.

[0076] The server controller 401 determines whether any three adjacent communication coils among the multiple power-transmitter communication coils 40 arranged along the road RS are in the relationship shown in FIG. 11. The method of determining whether the mark is ○ or × in the case of FIG. 11 is the same as that in the case of FIG. 9 (a1).

[0077] In step S22, the server controller 401 determines whether a communication abnormality in the power-transmitter communication coils 40 has been detected in step S21. When it is determined that no communication abnormality has been detected, the server controller 401 proceeds to step S23 and makes a definitive determination that no abnormality has occurred in the communication function of the power transmitter 20.

[0078] On the other hand when it is determined that a communication abnormality has been detected, the server controller 401 proceeds to step S24 and makes a definitive determination that an abnormality has occurred in the communication function of the power transmitter 20. In next step S25, the server controller 401 notifies an external device (for example, a server of a management company of the wireless power transfer system 10) that an abnormality has occurred, for example, via the wide area wireless communication shown in FIG. 4. Accordingly, the power transmitter 20 can be prevented from being used continuously in an undesirable state.

[0079] According to the present embodiment described above, it is possible to determine whether there is an abnormality in the communication function of the power transmitter 20.

[0080] Modification of First Embodiment When the server controller 401 determines that the intensity Intd received in step S20 exceeds the upper limit IHlimit, the server controller 401 may determine that a communication abnormality has occurred in a power-transmitter communication coil 40 corresponding to the intensity Intd that exceeds the upper limit IHlimit.

[0081] Second Embodiment A second embodiment will be described below with reference to the drawings mainly in terms of differences from the first embodiment. In this embodiment, when it is determined multiple times that a communication abnormality has been detected in the power-transmitter communication coil 40, a definitive determination is made that an abnormality has occurred in the communication function of the power transmitter 20.

[0082] FIG. 12 is a flowchart illustrating a procedure of a process for diagnosing the communication function of the power transmitter 20. The diagnostic process of FIG. 12 is repeatedly executed by the server controller 401.

[0083] When the server controller 401 determines in step S22 that a communication abnormality has been detected, the server controller 401 proceeds to step S30 and increments a counter Cnt by one. The initial value of the counter Cnt is zero.

[0084] In step S31, the server controller 401 determines whether the counter Cnt has reached a threshold Cth. The threshold Cth is an integer equal to or greater than two. When the server controller 401 determines that the counter Cnt has reached the threshold Cth, the server controller 401 proceeds to step S24, and makes a definitive determination that an abnormality has occurred in the communication function of the power transmitter 20. In other words, when the server controller 401 consecutively determines multiple times that a communication abnormality has been detected, the server controller 401 makes the definitive determination that an abnormality has occurred.

[0085] According to the present embodiment described above, it is possible to improve an accuracy of abnormality determination.

[0086] Third Embodiment A third embodiment will be described below with reference to the drawings mainly in terms of differences from the first embodiment. In this embodiment, the server controller 401 makes a definitive determination that an abnormality has occurred in the communication function of the power transmitter 20 when the ratio of the number of times a communication abnormality is detected to the number of times the diagnostic process is executed reaches a predetermined ratio.

[0087] FIG. 13 is a flowchart illustrating a procedure of a process for diagnosing the communication function of the power transmitter 20. The diagnostic process of FIG. 13 is repeatedly executed by the server controller 401.

[0088] When the server controller 401 determines in step S22 that a communication abnormality has not been detected, the server controller 401 proceeds to step S40 through step S23, and increments a normality counter Ctb by one. The initial value of the normality counter Ctb is zero.

[0089] When the server controller 401 determines in step S22 that a communication abnormality has been detected, the server controller 401 proceeds to step S41 and increments an abnormality counter Cta by one. The initial value of the abnormality counter Cta is zero.

[0090] In step S42, the server controller 401 calculates a total counter Ctotal, which is the sum of the abnormality counter Cta and the normal counter Ctb.

[0091] In step S43, the server controller 401 determines whether the total counter Ctotal has reached a total threshold Ath. The total threshold Ath is an integer equal to or greater than two.

[0092] When the server controller 401 determines that the total counter Ctotal has reached the total threshold Ath, the server controller 401 proceeds to step S44, and determines whether the abnormality counter Cta has reached a definite threshold Bth. The definite threshold Bth is an integer equal to or greater than one and is smaller than the total threshold Ath.

[0093] When the server controller 401 determines that the abnormality counter Cta has reached the definite threshold Bth, the server controller 401 proceeds to step S24, and makes a definitive determination that an abnormality has occurred in the communication function of the power transmitter 20.

[0094] An example will be described, in which the total threshold Ath is set to ten and the definite threshold Bth is set to one. It is assumed that ten vehicles pass over a certain power-transmitter coil unit 21 and the determination in step S22 is affirmative for one of the ten vehicles. In this case, the server controller 401 makes a definitive determination that an abnormality has occurred when the ratio of the number of times (one time) an affirmative determination is made in step S22 to the number of times (ten times) the diagnostic process shown in FIG. 13 (specifically, the series of processes from START to END) is executed reaches a predetermined ratio (10%).

[0095] When the server controller 401 makes negative determination in step S44, the server controller 401 proceeds to step S45 and resets the abnormality counter Cta and the normality counter Ctb to zero.

[0096] According to the present embodiment described above, even if an affirmative determination is made in step S22 due to a malfunction on the vehicle 11, the influence of the malfunction on the diagnosis result can be reduced.

[0097] Fourth Embodiment Hereinafter, a fourth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the server controller 401 determines that an abnormality has occurred in the communication function of the power transmitter 20 when the total number of times that communication abnormalities have been detected in a predetermined period of time reaches a predetermined number.

[0098] FIG. 14 is a flowchart illustrating a procedure of a process for diagnosing the communication function of the power transmitter 20. The diagnostic process of FIG. 14 is repeatedly executed by the server controller 401.

[0099] In step S50, the server controller 401 counts an elapsed time that has elapsed since a reference timing, and then proceeds to step S20.

[0100] When the server controller 401 determines in step S22 that a communication abnormality has been detected, the server controller 401 proceeds to step S51 and increments an abnormality counter Cta by one. The initial value of the abnormality counter Cta is zero.

[0101] When the process of step S51 is completed, the server controller 401 proceeds to step S52 and determines whether the elapsed time counted in step S50 has reached a predetermined period Tjde. The predetermined period Tjde is set, for example, to "5 minutes ≦ Tjde ≦ 10 minutes", "5 minutes ≦ Tjde ≦ 1 hour", or "5 minutes ≦ Tjde ≦ 6 hours". When the server controller 401 determines that the elapsed time has reached the predetermined time Tjde, the server controller 401 proceeds to step S53 and determines whether the abnormality counter Cta has reached a definite threshold Dth. The definite threshold Dth is an integer equal to greater than one.

[0102] When the server controller 401 determines that the anomaly counter Cta is less than the definite threshold Dth, the server controller 401 proceeds to step S23 and determines that no anomaly has occurred in the communication function of the power transmitter 20. In step S54, the server controller 401 resets the abnormality counter Cta to zero.

[0103] On the other hand, when the server controller 401 determines that the abnormality counter Cta has reached the definite threshold Dth, the server controller 401 proceeds to step S24, and makes a definitive determination that an abnormality has occurred in the communication function of the power transmitter 20.

[0104] According to the above present embodiment, the same effect as that of the third embodiment can be obtained.

[0105] Fifth Embodiment Hereinafter, a fifth embodiment will be described with reference to the drawings, focusing on the differences from the above-described embodiments. In this embodiment, as shown in FIG. 15, a predetermined number of two or more (four is illustrated in the figure) of power-transmitter coil units 21 arranged along the road RS are connected to one power-transmitter power supply unit 51. In other words, one power-transmitter power supply unit 51 is provided for each of the four power-transmitter coil units 21.

[0106] A power-transmitter control unit 70 of each power-transmitter power supply unit 51 calculates an intensity Intd corresponding to each power-transmitter communication coil 40 based on the received signals of the predetermined number of power-transmitter communication coils 40 provided corresponding to the power-transmitter control unit 70. Each power-transmitter control unit 70 performs the process shown in FIG. 7 described above.

[0107] In step S21 of the diagnostic process, the server controller 401 determines that a communication abnormality has occurred in some communication coils among the predetermined number of power-transmitter communication coils 40 provided corresponding to each power-transmitter control unit 70 when the server controller 401 determines that the some communication coils have not received the power supply request signal, and the remaining communication coils have received the power supply request signal, based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd. FIG. 16 shows an example in which a communication abnormality has occurred in the third communication coil from the upstream side in the vehicle travel direction, out of a predetermined number (four) of power-transmitter communication coils 40 provided corresponding to a certain power-transmitter control unit 70.

[0108] According to the present embodiment described above, a communication abnormality in the power transmitter 20 can also be detected.

[0109] Modification of Fifth Embodiment The subject of the diagnostic process is not limited to the server 400, and may be each of the power-transmitter control units 70.

[0110] Sixth Embodiment Hereinafter, a sixth embodiment will be described with reference to the drawings, focusing on the differences from the above-described embodiments. In this embodiment, the process of step S21 in the diagnostic process is modified.

[0111] FIG. 17 shows a vehicle 11 traveling in a lane LL. In FIG. 17, D2 is the distance in the vehicle width direction (hereinafter referred to as the "deviation degree") between the central position in the vehicle width direction of the power-receiver coil unit 101 (i.e., power-receiver communication coil 170) and the central position in the vehicle width direction of the power-transmitter coil unit 21 (i.e., power-transmitter communication coil 40).

[0112] The communication range of the power-receiver communication coil 170 mounted on the vehicle 11 may be, for example, an elliptical communication range 500 as indicated by the dashed dotted line. That is, in this case, the communication range in the vehicle width direction becomes narrower toward the front or rear end of the vehicle 11 in the vehicle length direction. In other words, the communication range in the vehicle length direction becomes narrower toward ends of the vehicle 11 in the vehicle width direction. In this case, even if the transmission intensity of the power supply request signal from the power-receiver communication coil 170 is the same, the reception intensity of the power supply request signal by the power-transmitter communication coil 40 may change depending on the deviation degree D2.

[0113] The server controller 401 determines whether both a first condition and a second condition are satisfied based on the intensity Intd received from each power-transmitter controller 71, the time information associated with each intensity Intd, and the coil identification information associated with each intensity Intd.

[0114] The first condition is that the intensity Intd of the power supply request signal received by each of upstream and downstream communication coils in the vehicle travel direction among three adjacent power-transmitter communication coils 40 is within the range "ILlimit ≦ Intd ≦ IHlimit".

[0115] The second condition is that the intensity Intd of the power supply request signal received by a middle communication coil between the upstream and downstream communication coils in the vehicle travel direction among the three adjacent power-transmitter communication coils 40 is lower than the lower limit ILlimit, or that the power supply request signal is not received by the middle communication coil.

[0116] When the server controller 401 determines that both the first condition and the second condition are satisfied, the server controller 401 determines that a communication abnormality has occurred in the middle communication coil.

[0117] FIG. 18 shows a travel path Dtr of the vehicle 11 when the deviation degree D2 is 0. In the example shown in FIG. 18, the intensities Intd of the power supply request signals received by the power-transmitter communication coils 40 sequentially from the upstream side in the vehicle travel direction are 85%, 90%, 50%, 80%, 85%, and 85%. In the example shown in FIG. 18, for convenience, the expected intensity range of the intensity is set to 70% to 100%. The intensity Intd displayed as a percentage (%) is, for example, as described above, the maximum intensity during the period from when the intensity starts to gradually increase, then gradually decreases, and until it starts to gradually increase again. In the example shown in FIG. 18, the server controller 401 focuses on the second to fourth power-transmitter communication coils 40 from the upstream side, and determines that the first and second conditions are satisfied. The server controller 401 determines that a communication abnormality has occurred in the third power-transmitter communication coil 40 from the upstream side.

[0118] The number of middle communication coils is not limited to one, but may be N, which is two or more. In this case, the server controller 401 may focus on the "N+2" power-transmitter communication coils 40 arranged adjacent to each other.

[0119] When the server controller 401 determines that the intensity Intd of the power supply request signal received by an upstream antenna group, which consists of multiple power-transmitter communication coils 40 adjacent to each other, is within the range "ILlimit ≦ Intd ≦ IHlimit" and that the intensity Intd of the power supply request signal received by a downstream antenna group, which is an antenna group adjacent to the downstream side of the upstream antenna group in the vehicle travel direction and consists of multiple power-transmitter communication coils 40 adjacent to each other, is lower than the lower limit ILlimit, the server controller 401 determines that no communication abnormality has occurred in the downstream antenna group.

[0120] FIG. 19 shows a travel path Dtr of the vehicle 11 when the deviation degree D2 becomes greater than 0 midway. In the example shown in FIG. 19, the intensities Intd of the power supply request signals received by the power-transmitter communication coils 40 sequentially from the upstream side in the vehicle travel direction are 80%, 75%, 50%, 50%, 48%, and 52%. In the example shown in FIG. 19, the first and second power-transmitter communication coils 40 from the upstream side constitute the upstream antenna group. The third to sixth power-transmitter communication coils 40 from the upstream side constitute the downstream antenna group. When the server controller 401 determines that no communication abnormality has occurred in the downstream antenna group, it may notify the vehicle with a large deviation degree D2, for example, via wide area wireless communication, that the deviation degree D2 is large.

[0121] According to the present embodiment described above, even when the deviation degree is greater than 0, it is possible to improve the accuracy of determining whether there is a communication abnormality in the power transmitter 20.

[0122] Modification of Sixth Embodiment When the configuration of FIG. 15 is employed, the execution subject of the diagnostic process is not limited to the server 400, but may be each power-transmitter control unit 70.

[0123] Other Embodiments The above embodiments may be changed and carried out as follows.

[0124] In each of the above embodiments, the execution subject of the diagnostic process is not limited to the server controller 401, and may be, for example, a higher-level controller (not shown) that controls each of the power-transmitter power supply units 51. Furthermore, among the power-transmitter control units 70, when information of a power-transmitter control unit is input to another specific power-transmitter control unit, the diagnostic process may be executed by the specific power-transmitter control unit.

[0125] The power-receiver communication antenna and the power-transmitter communication antenna are not limited to communication coils, and may employ various antennas. For example, the communication antenna is a dipole antenna or a monopole antenna.

[0126] The method of wireless power transmission by the power transmitting antenna and the power receiving antenna is not limited to the magnetic field resonance method, and may be an electric field coupling method. In this case, a power transmitting antenna and a power receiving antenna that are different in form from coils and use an electric field coupling method may be used.

[0127] The wireless power transfer system may have the first function of wirelessly supplying power from the vehicle-side device to the ground-side device, in addition to the second function of wirelessly supplying power from the ground-side device to the vehicle-side device. In this case, the in-vehicle power receiver 100 has a power transmitting function in addition to the power receiving function. Moreover, the power transmitter 20 on the ground side has a power receiving function in addition to the power transmitting function. The second function will be described below with reference to FIG. 3.

[0128] The power-receiver controller 231 applies a high frequency AC voltage to the power receiver coil 102 by controlling the switching of the rectifier circuit 200. This causes a high-frequency current to flow in the power receiver coil 102 and a magnetic field for power transmission is generated in the power receiver coil 102.

[0129] When the magnetic field generated in the power receiver coil 102 links with the power transmitter coil 22, a high-frequency current flows in the power transmitter coil 22, varying with the frequency of the high-frequency current flowing in the power receiver coil 102. The high-frequency current flowing through the power transmitter coil 22 is supplied to the AC power source 15 via the power-transmitter resonant circuit 30, the filter circuit 52, the inverter 60 and the PFC circuit 61. In this case, the power-transmitter controller 71 controls the switching of the inverter 60 and the PFC circuit 61.

[0130] In the wireless power transfer system having the second function, for example, the power transmitter 20 may include a signal transmitter that supplies a power supply request signal to the power-transmitter communication coil 40. Furthermore, the power receiver 100 may include a signal receiver that receives the power supply request signal received by the power-receiver communication coil 170 and inputs the information to the power-receiver controller 231.

[0131] The wireless power transfer system may have the function of wirelessly supplying power from the vehicle-side device to the ground-side device, instead of the function of wirelessly supplying power from the ground-side device to the vehicle-side device.

[0132] The vehicle identification information used in the processes of the above embodiments is not limited to vehicle ID information, and may be, for example, a token or credit card information of a vehicle user.

[0133] The vehicle on which the power receiver 100 is mounted is not limited to a vehicle traveling on the road RS, but may be, for example, an AGV (Automated Guided Vehicle) or a traveling robot. In this case, the power-transmitter coil unit 21 is not buried in the road RS, but may be installed on a sidewalk adjacent to the road RS, in a parking lot, or in the path along which the AGV travels.

[0134] The control units and methods thereof described in the present disclosure may be implemented by a dedicated computer including a processor programmed to execute one or more functions embodied by a computer program and a memory. Alternatively, the control units and methods thereof described in the present disclosure may be implemented using a dedicated computer with a processor consisting of one or more dedicated hardware logic circuits. Alternatively, the controller and method described in the present disclosure may be implemented using one or more dedicated computers, which include a combination of a processor consisting of one or more hardware logic circuits, and a processor and memory programmed to perform one or more functions. Further, the computer program may store a computer-readable non-transitional tangible recording medium as an instruction to be executed by the computer.

[0135] While the present disclosure has been described with reference to various exemplary embodiments thereof, it is to be understood that the disclosure is not limited to the disclosed embodiments and constructions. To the contrary, the disclosure is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the disclosure are shown in various combinations and configurations, which are exemplary, other various combinations and configurations, including more, less or only a single element, are also within the spirit of the disclosure.

Claims

1. A wireless power transfer system (10) comprising a ground-side device and a vehicle-side device, wherein one of the ground-side device and the vehicle-side device is a power transmitter (20) having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device is a power receiver (100) having a power receiving antenna (102), the power receiver is configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter is configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter includes a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) provided in the power receiver, and the wireless power transfer system further comprises a diagnostic unit (70, 400) configured to execute a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

2. The wireless power transfer system according to claim 1, wherein the power receiver is installed in a vehicle as the vehicle-side device, the power transmitter is provided as the ground-side device, the power transmitting antenna is one of power transmitting antennas arranged at predetermined intervals in a vehicle travel direction, the power-transmitter communication antenna is one of power-transmitter communication antennas corresponding, respectively, to the power transmitting antennas, the diagnostic unit is configured, in the diagnostic process, to determine that a communication abnormality has occurred in a communication antenna that has not received the power supply request signal among two adjacent power-transmitter communication antennas on condition that the diagnostic unit determines that, among the two adjacent power-transmitter communication antennas, an upstream communication antenna in the vehicle travel direction has received the power supply request signal, and then a downstream communication antenna in the vehicle travel direction has not received the power supply request signal, or on condition that the diagnostic unit determines that, among the two adjacent power-transmitter communication antennas, an upstream communication antenna in the vehicle travel direction has not received the power supply request signal, and then a downstream communication antenna in the vehicle travel direction has received the power supply request signal.

3. The wireless power transfer system according to claim 2, wherein the diagnostic unit is configured, in the diagnostic process, to determine that a communication abnormality has occurred in a middle communication antenna among three adjacent power-transmitter communication antennas on condition that the diagnostic unit determines that an upstream communication antenna in the vehicle travel direction has received the power supply request signal, then the middle communication antenna in the vehicle travel direction has not received the power supply request signal, and then a downstream communication antenna in the vehicle travel direction has received the power supply request signal.

4. The wireless power transfer system according to claim 1, wherein the power receiver is installed in a vehicle as the vehicle-side device, the power transmitter is provided as the ground-side device, the power transmitting antenna is one of power transmitting antennas arranged at predetermined intervals in a vehicle travel direction, the power-transmitter communication antenna is one of power-transmitter communication antennas corresponding, respectively, to the power transmitting antennas, the power transmitter includes a power-transmitter control unit (70) configured to control energization of the power transmitting antennas based on signals received by the power-transmitter communication antennas, the power-transmitter control unit is provided for each group of a predetermined number of power-transmitter communication antennas, the predetermined number is two or more, and the diagnostic unit is configured, in the diagnostic process, to determine that a communication abnormality has occurred in some communication antennas among the predetermined number of power-transmitter communication antennas corresponding to each power-transmitter control unit on condition that the diagnostic unit determines that the some communication antennas has not received the power supply request signal and remaining communication antennas have received the power supply request signal.

5. The wireless power transfer system according to claim 2, wherein the diagnostic unit is configured, in the diagnostic process, to calculate an intensity of the power supply request signal based on a signal received by each power-transmitter communication antenna, determine that a communication abnormality has occurred in a middle communication antenna among three adjacent power-transmitter communication antennas on condition that the diagnostic unit determines that (i) the intensity of the power supply request signal received by an upstream communication antenna in the vehicle travel direction among the three adjacent power-transmitter communication antennas is within an expected intensity range, (ii) the intensity of the power supply request signal received by the middle communication antenna between upstream and downstream communication antennas in the vehicle travel direction among the three adjacent power-transmitter communication antennas is less than a lower limit of the expected intensity range, or the power supply request signal is not received by the middle communication antenna, and (iii) the intensity of the power supply request signal received by a downstream communication antenna in the vehicle travel direction among the three adjacent power-transmitter communication antennas is within the expected intensity range.

6. The wireless power transfer system according to claim 5, wherein the diagnostic unit is configured, in the diagnostic process, to determine that no communication abnormality has occurred in a downstream antenna group consisting of multiple power-transmitter communication antennas adjacent to each other, when determining that (i) the intensity of the power supply request signal received by an upstream antenna group consisting of multiple power-transmitter communication antennas adjacent to each other is within the expected intensity range, and (ii) the intensity of the power supply request signal received by the downstream antenna group that is adjacent to a downstream side of the upstream antenna group in the vehicle travel direction is lower than the lower limit.

7. The wireless power transfer system according to any one of claims 2 to 6, wherein the diagnostic unit is configured to make a definitive determination that an abnormality has occurred when the diagnostic unit determines multiple times that the abnormality has occurred.

8. The wireless power transfer system according to any one of claims 2 to 6, wherein the diagnostic unit is configured to make a definitive determination that an abnormality has occurred when a ratio of a number of times the diagnostic unit determines that the abnormality has occurred to a number of times the diagnostic process has been executed reaches a predetermined ratio.

9. The wireless power transfer system according to any one of claims 2 to 6, wherein the diagnostic unit is configured to make a definitive determination that an abnormality has occurred when a total number of times the diagnostic unit determines that the abnormality has occurred reaches a predetermined number within a predetermined period of time.

10. A program for a wireless power transfer system (10) including a ground-side device and a vehicle-side device, one of the ground-side device and the vehicle-side device being a power transmitter (20) having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device being a power receiver (100) having a power receiving antenna (102), the power receiver being configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter being configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter including a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) provided in the power receiver, the program configured to cause the wireless power transfer system to carry out: executing a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

11. A control method for a wireless power transfer system (10) including a ground-side device and a vehicle-side device, one of the ground-side device and the vehicle-side device being a power transmitter (20) having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device being a power receiver (100) having a power receiving antenna (102), the power receiver being configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter being configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter including a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) provided in the power receiver, the control method comprising: causing the wireless power transfer system to execute a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

12. A power transmitter (20) applied to a wireless power transfer system (10) including a ground-side device and a vehicle-side device, one of the ground-side device and the vehicle-side device being the power transmitter having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device being a power receiver (100) having a power receiving antenna (102), the power receiver being configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter being configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter comprising: a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) of the power receiver; and a power-transmitter control unit (70) configured to control energization of the power transmitting antenna based on a signal received by the power-transmitter communication antenna, wherein the power-transmitter control unit is configured to execute a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

13. A program for a power transmitter (20) applied to a wireless power transfer system (10) including a ground-side device and a vehicle-side device, one of the ground-side device and the vehicle-side device being the power transmitter (20) having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device being a power receiver (100) having a power receiving antenna (102), the power receiver being configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter being configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter including a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) provided in the power receiver, the power transmitter including a power-transmitter control unit (70) configured to control energization of the power transmitting antenna based on a signal received by the power-transmitter communication antenna, the program configured to cause the power-transmitter control unit to carry out: executing a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

14. A control method for a power transmitter (20) applied to a wireless power transfer system (10) including a ground-side device and a vehicle-side device, one of the ground-side device and the vehicle-side device being the power transmitter (20) having a power transmitting antenna (22), the other of the ground-side device and the vehicle-side device being a power receiver (100) having a power receiving antenna (102), the power receiver being configured to transmit a power supply request signal for a power supply request to the power transmitter, the power transmitter being configured to energize the power transmitting antenna to perform wireless power transfer to the power receiving antenna on condition that the power transmitter receives the power supply request signal, the power transmitter including a power-transmitter communication antenna (40) configured to receive the power supply request signal wirelessly transmitted from a power-receiver communication antenna (170) provided in the power receiver, the power transmitter including a power-transmitter control unit (70) configured to control energization of the power transmitting antenna based on a signal received by the power-transmitter communication antenna, the control method comprising: causing the power-transmitter control unit to execute a diagnostic process determining whether a communication abnormality has occurred in the power transmitter based on a signal reception state of the power-transmitter communication antenna.

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