Power transmitter device, program, control method for power transmitter device

Abstract

A power-transmitter control unit (70) provided in a power transmitter device (20) acquires information on output characteristic of a power receiver circuit (500), determines whether a combination of the acquired output characteristic and the output characteristic of a power transmitter circuit (400) is an appropriate combination, and starts a power transfer control of the power transmitter circuit (400) on determining that the combination is an appropriate one.

Description

POWER TRANSMITTER DEVICE, PROGRAM, CONTROL METHOD FOR POWER TRANSMITTER DEVICECross Reference

[0001] This application is based on Japanese Application No. 2025-019562 filed on February 07, 2025, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power transmitter device, a program, and a method for controlling the power transmitter device.

[0003] Conventionally, as described in Patent Literature 1, for example, a wireless power transfer system has been known which includes a power transmitter circuit having a power transmitter coil arranged in a vehicle's travel path, and a power receiver circuit having a power receiving coil and provided in a vehicle, and which performs wireless power transfer from the power transmitter coil to the power receiving coil.

[0004] JP2024-122073A

[0005] When a combination of the output characteristic of the power receiving circuit and the output characteristic of the power transmitting circuit is not an appropriate combination, there is a concern that inconveniences may occur. For example, there is a concern that a large current may flow from the power receiving circuit to the vehicle battery during wireless power transfer.

[0006] It is an object of the present disclosure to provide a power transmitter device, a program, and a control method for a power transmitter device, which are capable of preventing a situation in which power transfer control of a power transmission antenna is continuously performed for wireless power transfer when a combination of output characteristic of a power receiver circuit and output characteristic of a power transmitter circuit is not an appropriate combination.

[0007] The first aspect of the present disclosure relates to a power transmitter device applicable to a wireless power transfer system, in which one of a ground side device on a ground and a vehicle side device on a vehicle is a power transmitter device including a power transmitter antenna and an other of the ground side device and the vehicle side device is a power receiver device including a power receiver antenna, for transmission of electric power in a wireless manner to the power receiver antenna by supplying electric power to the power transmitter antenna. The power transmitter device comprises: a power transmitter circuit including the power transmitter antenna; and a power-transmitter control unit configured to perform power transfer control of the power transmitter circuit for wireless power transfer. The power receiver device includes a power receiver circuit including the power receiver antenna. The power-transmitter control unit is configured to acquire an output characteristic of the power receiver circuit, determine whether a combination of the output characteristic as acquired and an output characteristic of the power transmitter circuit is an appropriate combination, and start the power transfer control of the power transmitter circuit, on determining that the combination is the appropriate combination.

[0008] In such manner, it is possible to prevent a situation in which the power transfer control of the power transmitter antenna continues for wireless power transfer in a state in which the combination of the output characteristic of the power receiver circuit and the output characteristic of the power transmitter circuit is not an appropriate combination. The second aspect of the present disclosure relates to the power transmitter device according to the first aspect, in which the power-transmitter control unit is configured to after the power transfer control of the power transmitter circuit is started, re-determine whether the combination of the output characteristic as acquired and the output characteristic of the power transmitter circuit is the appropriate combination by using a method different from a method used for determination of whether the combination is the appropriate combination before the power transfer control is started, and continue the power transfer control of the power transmitter circuit when re-determining that the combination is the appropriate combination.

[0009] There may be a situation in which, even when the combination is not the appropriate combination, the combination is erroneously determined as appropriate due to, for example, an influence of noise on information on the acquired output characteristic.

[0010] Therefore, in the second aspect, after the start of the power transfer control of the power transmitter circuit, the power transmitter controller continues the power transfer control of the power transmitter circuit on condition that (a) whether a combination is re-determined as an appropriate one or not, in which the appropriateness is determined regarding a combination of (i) the acquired output characteristic of the power receiver circuit, and (ii) the output characteristic of the power transmitter circuit, and (b) the combination is re-determined as an appropriate one. In other words, the power transfer control is stopped when the combination is not re-determined as an appropriate one.

[0011] In such manner, it is possible to preferably prevent a situation in which the power transfer control of the power transmitter antenna is continuously performed for wireless power transfer when the combination of the output characteristic of the power receiver circuit and the output characteristic of the power transmitter circuit are not an appropriate combination.

[0012] The drawings described herein are intended to illustrate selected embodiments, do not depict all possible embodiments, 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 of a power transmitter device and a power receiver device.FIG. 4 is a diagram of a configuration of wide-area wireless communication between the power transmitter device and a vehicle.FIG. 5 is a diagram of an example of an appropriate combination of a power transmitter circuit and a power receiver circuit in an SS type.FIG. 6 is a diagram of an example of an appropriate combination of a power transmitter circuit and a power receiver circuit in a Double-LCC type.FIG. 7 is a diagram of an example in which the combination of a power transmitter circuit and a power receiver circuit is not an appropriate combination.FIG. 8 is a flowchart of a process performed by the power transmitter device.FIG. 9 is another flowchart of a process performed by the power transmitter device.FIG. 10 is a flowchart of a process performed by the power transmitter device according to a second embodiment.FIG. 11 is another flowchart of a process performed by the power transmitter device.

[0013] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be labeled with the same reference numerals or with reference numerals that differ in the hundred or higher digits. The corresponding and / or associated parts may refer to the explanation in the other embodiments.

[0014] <First Embodiment> The first embodiment of a wireless power transfer system of the present disclosure will be described in the following with reference to the drawings.

[0015] First, an overall configuration of the wireless power transfer system will be described. As shown in FIGs. 1, 2 and 3, a wireless power transfer system 10 includes a power transmitter device 20 and a power receiver device 100. The power receiver device 100 is a vehicle-side device, which is mounted on a vehicle 11, as a moving object driving on a road RS. The vehicle 11 is, for example, an electric vehicle or a hybrid vehicle. While the vehicle 11 is traveling or stopped, electric power is supplied from the power transmitter device 20 to the power receiver device 100. The wireless power transfer system 10 performs wireless power transmission from the power transmitter device 20 to the power receiver device 100 by magnetic field resonant coupling (magnetic field resonance). The wireless power transfer system 10 is also referred to as a dynamic wireless power transmission (D-WPT) system.

[0016] The power transmitter device 20 is a ground-side device, and includes a power-transmitter coil unit 21 and a power-transmitter power source unit 51 that supplies electric power to the power-transmitter coil unit 21. The power transmitter device 20 is, for example, a stationary device. The power-transmitter coil unit 21 is installed (for example, buried) on the road RS, a parking lot, or the like. The power-transmitter power source unit 51 is installed, for example, at a roadside of the road RS. The power-transmitter coil unit 21 is connected to the power-transmitter power source unit 51. The power-transmitter power source unit 51 is connected to an AC power source 15, and supplies AC 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. FIG. 2 shows an example in which four power-transmitter coil units 21 disposed in series along the road RS are connected to one power-transmitter power source unit 51. In other words, one power-transmitter power source unit 51 is provided for every four power-transmitter coil units 21.

[0017] Note that the configuration is not limited to one power-transmitter power source unit 51 for a unit of the multiple power-transmitter coil units 21, but one power-transmitter power source unit 51 may be provided for one power-transmitter coil unit 21.

[0018] The power-transmitter power source 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.

[0019] The inverter 60 is connected to the PFC circuit 61. The DC power input from the PFC circuit 61 is converted into AC power by controlling the switching of the switching elements (for example, IGBTs or MOSFETs) included in the inverter 60.

[0020] 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 including a coil and a capacitor. Circuits having various configurations may be used as the filter circuit 52, and, for example, a T-type filter circuit is used as the filter circuit 52.

[0021] The power-transmitter coil unit 21 includes a power transmitter coil 22 (corresponding to a power transmitter 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 from the filter circuit 52 to the power transmitter coil 22. The power-transmitter resonant circuit 30 may be implemented as various well-known resonant circuits such as a circuit including a resonant capacitor.

[0022] In the present embodiment, the inverter 60, the filter circuit 52 and the power-transmitter resonant circuit 30 constitute a power transmitter circuit 400.

[0023] The power receiver device 100 includes a power receiver coil unit 101 and a power-receiving power source unit 181. The power receiver coil unit 101 includes a power receiver coil 102 (corresponding to a “power receiver antenna”). The power receiver coil unit 101 is provided at a bottom of a vehicle body of the vehicle 11. The power receiver coil unit 101 is provided at the bottom of the vehicle body to face a surface of the ground. 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 and the power receiver coil 102 of the vehicle 11 face each other in the vertical direction.

[0024] The power receiver device 100 includes a power-receiver resonant circuit 140. The power receiver coil 102 is connected to the power-receiver resonant circuit 140. Electric power is transmitted to the power receiver coil 102 from the power transmitter coil 22. The power receiver coil 102 supplies the received electric power to the power-receiver resonant circuit 140. The power-receiver resonant circuit 140 may be implemented as various well-known resonant circuits such as a circuit including a resonant capacitor.

[0025] The power receiver 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-receiver resonant circuit 140, and supplies the AC current from which the 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 a reactor and a capacitor.

[0026] 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 may also be referred to as an ERB (Electronic Rectification Box).

[0027] In the present embodiment, the power-receiver resonant circuit 140, the filter circuit 182 and the rectifier circuit 200 constitute a power receiver circuit 500.

[0028] The vehicle 11 includes a high-potential main switch 301H, a low-potential main switch 301L, and a high-voltage power 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). A high-potential side output terminal of the rectifier circuit 200 is connected to a positive-electrode terminal of the high-voltage power storage battery 300 via the high-potential main switch 301H. A low-potential side output terminal of the rectifier circuit 200 is connected to a negative-electrode terminal of the high-voltage power storage battery 300 via the low-potential main switch 301L. The high-voltage power storage battery 300 is a secondary battery that may be charged and discharged, and has a rated voltage of, for example, several hundred volts. The high-voltage power storage battery 300 is, for example, a lithium-ion storage battery or a nickel-metal hydride storage battery.

[0029] The vehicle 11 includes a drive inverter 310 and a rotary electric machine 320. The drive inverter 310 is a three-phase inverter, and is connected to the high-voltage power storage battery 300 via the high-potential main switch 301H and the low-potential main switch 301L. An armature winding of the rotary electric machine 320 is connected to upper and lower arm switches constituting the drive inverter 310. With the high-potential main switch 301H and the low-potential main switch 301L switched on, the switching of the upper and lower arm switches of the drive inverter 310 is controlled such that the drive inverter 310 converts the DC power supplied from the high-voltage power storage battery 300 into the AC power, and supplies the AC power to the armature winding. In such manner, the rotor of the rotary electric machine 320 rotates, and wheels 12 (drive wheels) of the vehicle 11 rotate by the rotational power of the rotor. As a result, the vehicle 11 travels.

[0030] In the present embodiment, the high-voltage power storage battery 300 and the drive inverter 310 respectively correspond to a “power transfer target device.”

[0031] As shown in FIG. 3, the power-transmitter power source unit 51 constituting the power transmitter device 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 performs various controls of the power transmitter device 20 and includes, as hardware, a processor, a storage unit, and a communication bus connecting the processor and the storage unit.

[0032] The storage unit includes a memory and a storage as hardware. The memory is a storage device for memorizing data used in the processing of the power transmitter controller 71. The memory provides the processor with, for example, a working area for temporary use when the processor performs processing. The memory includes, for example, a ROM or a RAM. 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, an HDD or a flash memory. The storage memorizes program information and other information for the processes described later.

[0033] The power-receiving power source unit 181, which constitutes the power receiver device 100, includes a power receiver controller 231. The power receiver controller 231 is an ECU that performs various controls of the power receiver device 100, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and the storage unit.

[0034] 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 provides the processor with, for example, a working area for temporary use when the processor performs processing. The memory includes, for example, a ROM or a RAM. 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, an HDD or a flash memory. The storage stores program information and the like for the processing described in the following.

[0035] The power transmitter controller 71 performs switching control of the PFC circuit 61 and switching control of the inverter 60. A high-frequency AC voltage is applied to the power transmitter coil 22 by controlling the switching of the inverter 60. In such manner, a high-frequency electric current flows through the power transmitter coil 22, and a magnetic field for power-transmitter is generated in the power transmitter coil 22.

[0036] In the present embodiment, the power transmitter controller 71 controls the switching of the inverter 60 so that the frequency of the high-frequency voltage applied to the power transmitter coil 22 becomes a first specified frequency (specifically, 85 kHz) that is equal to or higher than 10 kHz and equal to or lower than 100 GHz. The resonance frequencies of the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 are set to the same frequency as the first specified frequency or to a frequency close to the first specified frequency.

[0037] When the magnetic field generated in the power transmitter coil 22 interlinks with the power receiver coil 102 of the vehicle 11, a high-frequency electric current that fluctuates with the frequency of the high-frequency electric current energizing the power transmitter coil 22 flows through the power receiver coil 102. The high-frequency electric current energizing the power receiver coil 102 is supplied to the rectifier circuit 200 via 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. When the high-potential main switch 301H and the low-potential main switch 301L are switched on, the output current of the rectifier circuit 200 is supplied to the high-voltage power storage battery 300 and the drive inverter 310.

[0038] The vehicle 11 includes a low-voltage power storage battery 302. The rated voltage of the low-voltage power storage battery 302 is lower than the rated voltage of the high-voltage power storage battery 300. The low-voltage power storage battery 302 is, for example, a lead power storage battery. When electric power is supplied from the low-voltage power storage battery 302 to the power receiver controller 231, the power receiver controller 231 becomes operable.

[0039] The power receiver device 100 and the power transmitter device 20 each have a configuration for communication between the power receiver device 100 and the power transmitter device 20. In detail, the power receiver coil unit 101 constituting the power receiver device 100 includes a power-receiver communication coil 170 (corresponding to a “power-receiving communication antenna”). A power-receiving control unit 230 includes a transmitter 240.

[0040] The power-transmitter coil unit 21, which constitutes the power transmitter device 20, includes a power-transmitter communication coil 40 (corresponding to a “power-transmitter communication antenna”). The power-transmitter control unit 70 includes a receiver 80. The power-receiver communication coil 170 and the power-transmitter communication coil 40 are communication coils for performing narrow-area wireless communication. The narrow-area wireless communication is communication with a communication distance of less than 10 meters (for example, a maximum of 3 meters). Narrow-area wireless communication is a communication with a shorter communication distance than wide-area wireless communication.

[0041] Various short-range wireless communications may be used as the narrow-area wireless communication. For example, communications compliant with any communication standards established by IEEE, ISO, IEC or the like may 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.

[0042] The transmitter 240 is connected to the power receiver controller 231. The power-receiver communication coil 170 is connected to the transmitter 240. The power receiver controller 231 controls the transmitter 240 to supply a power transfer request signal COMM to the power-receiver communication coil 170. The power transfer request signal COMM is a signal requesting the power transmitter coil 22 near the vehicle 11 to transmit electric power to the power receiver coil 102.

[0043] The power-receiving control unit 230 supplies a vehicle-side signal, which includes the power transfer request signal COMM in one frame, to the power-receiver communication coil 170. In such manner, a high-frequency voltage is applied from the transmitter 240 to the power-receiver communication coil 170. As a result, a high-frequency electric current flows through the power-receiver communication coil 170, and a magnetic field for information communication is generated in the power-receiver communication coil 170. In the present embodiment, the power transfer request signal COMM includes (i) ID information of the vehicle 11 identifying the vehicle 11 and (ii) requested power Weq, which is a requested value of electric power to be supplied to the vehicle 11.

[0044] When (i) the power receiver coil unit 101 of the vehicle 11 approaches the power-transmitter coil unit 21 on the ground, and (ii) the magnetic field generated by the power-receiver communication coil 170 interlinks with the power-transmitter communication coil 40, a high-frequency electric current flows through the power-transmitter communication coil 40. The high-frequency electric current is input to the receiver 80. The receiver 80 recognizes the presence or absence of a power transfer request and the ID information based on the input signal from the power-transmitter communication coil 40. The receiver 80 acquires the requested power Weq of the vehicle 11 having the recognized ID information based on the signal from the power-transmitter communication coil 40. The information recognized by the receiver 80 and the requested power Weq are input to the power transmitter controller 71.

[0045] In the present embodiment, the power receiver controller 231 controls the 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 the present embodiment, the second specified frequency is a frequency shifting from the first specified frequency described above, and is specifically a frequency higher than the first specified frequency (e.g., 13.56 MHz).

[0046] The power transmitter controller 71 determines whether to energize the power transmitter coil 22 based on the input signal from the receiver 80. In detail, on condition that it is determined that there is a power transfer request based on an input signal from the receiver 80, the power transmitter controller 71 applies a high-frequency voltage to the power transmitter coil 22 by controlling the switching of the inverter 60 and the PFC circuit 61.

[0047] That is, when it is determined that there is no power transfer request, the power transmitter controller 71 stops the switching control of the PFC circuit 61 and the inverter 60. In such manner, the switching elements of the PFC circuit 61 and the inverter 60 are kept off, and the power transmitter coil 22 is not energized.

[0048] On the other hand, when it is determined that there is a power transfer request, 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. In such manner, a high-frequency electric current flows through the power transmitter coil 22 for a predetermined period of time. In such 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 next time that there is a power transfer request.

[0049] Note that the power transmitter controller 71 performs frequency control when, for example, applying a high-frequency voltage to the power transmitter coil 22. Frequency control is a control that adjusts the effective power supplied from the inverter 60 to the filter circuit 52 by adjusting the frequency fout of the output voltage from the inverter 60 to the filter circuit 52. The power transmitter controller 71 alternately switches on (i) a pair of the first upper arm switch S1H and the second lower arm switch S2L and (ii) a pair of the first lower arm switch S1L and the second upper arm switch S2H to adjust the frequency fout of the output voltage based on the requested power Weq.

[0050] 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 of the vehicles 11 is capable of communicating with each of the power transmitter device 20 via a communication network 16. The communication network 16 includes, for example, a wide area network (WAN), which is a public communication network such as the Internet, a telephone communication network for mobile phones, an information and communication network of ETC, and an information and communication network for the vehicle information and communication system (VICS (registered trademark)). The wide-area wireless communication has a longer communication distance than narrow-area wireless communication. The wide-area wireless communication is communication with a communication distance of, for example, 10 meters to 10 kilometers. Examples of wide-area wireless communication may include 3GPP (registered trademark), 4G, LTE, 5G, and WiMAX (registered trademark) defined by IEEE.

[0051] The vehicle 11 includes a position sensor 330, a navigation device 331, and a communication unit 332. The position sensor 330 is a sensor that detects a current position of the vehicle, and is, for example, a GPS sensor. The 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 device 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.

[0052] The wireless power transfer system 10 includes a server 410. The server 410 is, for example, a cloud server, and includes a server controller 411 and a communication unit 412. The server controller 411 is an electronic control unit (ECU) that performs various controls of the server 410, and includes a processor as hardware, a storage unit, and a communication bus connecting the processor and the storage unit. The storage unit includes a memory and storage as hardware. The memory is a storage device for storing data used in the processing of the server controller 411. The memory provides the processor with, for example, a working area for temporary use when the processor performs processing. The memory includes, for example, a ROM or a RAM. 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, an HDD or a flash memory. The storage stores program information and the like for the processing described in the following.

[0053] The server controller 411 is connected to the communication unit 412. The server controller 411 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 412 and the communication network 16. For example, program information stored in a non-transitory, tangible storage medium is installed in the storage units of the power receiver controller 231, the power transmitter controller 71 and the server controller 411. The storage medium is, for example, a USB memory, a CD-ROM, or a DVD. Further, for example, program information transmitted via the communication network 16, such as over the air (OTA), is installed in the storage unit.

[0054] The output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 requested by the power receiver circuit 500 will be described. The output characteristic refers to a property that indicates what kind of electric current or voltage is used to supply electric power to a power-transmitter target (e.g., a power transfer target device or the like), which is a power transfer destination. The output characteristic includes, for example, a current source characteristic, with which electric power is supplied at a constant current to the power-transmitter target that is the power transfer destination, and a voltage source characteristic, with which electric power is supplied at a constant voltage to the power-transmitter target. There are also characteristics intermediate between the current source characteristic and the voltage source characteristic, which can generally be classified as being closer to either the current source characteristic or the voltage source characteristic. In the present embodiment, (i) those having the current source characteristic and (ii) those having a characteristic close to the current source characteristic are collectively referred to as a “current source,” and (iii) those having the voltage source characteristic and (iv) those having a characteristic close to the voltage source characteristic are collectively referred to as a “voltage source.”

[0055] Next, a combination of the output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 will be described. FIGs. 5 and 6 show examples of typical combinations.

[0056] FIG. 5 illustrates an example of an SS type wireless power transfer system. The power transmitter circuit 400 of such system includes a bandpass filter as the filter circuit 52. The bandpass filter includes a parallel capacitor 53A connected in parallel to the power transmitter coil 22, a series capacitor 53B connected in series to the power transmitter coil 22, and an inductor 53C connected in series to the series capacitor 53B. Further, the power transmitter circuit 400 also includes two series capacitors 23 as the power-transmitter resonant circuit 30. One end of the power transmitter coil 22 is connected to a first end of each of the series capacitors 23. Second ends of each of the series capacitors 23 are connected by the parallel capacitor 53A of the bandpass filter. In the present embodiment, the output characteristic of the power transmitter circuit 400 refer to the combined output characteristic of the inverter 60, the filter circuit 52, the power-transmitter resonant circuit 30 and the power transmitter coil 22.

[0057] The power receiver circuit 500 of the SS type wireless power transfer system includes a bandpass filter as the filter circuit 182. The bandpass filter includes a parallel capacitor 183A connected in parallel to the power receiver coil 102, a series capacitor 183B connected in series to the power receiver coil 102, and an inductor 183C connected in series to the series capacitor 183B. Further, the power receiver circuit 500 also includes two series capacitors 141 as the power-receiver resonant circuit 140. First ends of the series capacitors 141 are connected to each other by the power receiver coil 102. Second ends of the series capacitors 141 are connected by the parallel capacitor 183A of the bandpass filter. In the present embodiment, the output characteristic of the power receiver circuit 500 refer to the combined output characteristic of the power receiver coil 102, the power-receiver resonant circuit 140, the filter circuit 182 and the rectifier circuit 200.

[0058] In the SS type wireless power transfer system, the inverter 60 is supplied with electric power from the PFC circuit 61 that functions as a voltage source. The filter circuit 52 functions as a voltage source, due to non-functioning as an immittance converter that performs immittance conversion. Further, the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 function as immittance converters, thereby functioning as current sources. The filter circuit 182 functions as a current source, due to non-functioning as an immittance converter. In such manner, a power source for (i) the rectifier circuit 200 and (ii) the high-voltage power storage battery 300 functioning as a voltage source serves as a current source.

[0059] Note that, in FIG. 5, the power transmitter circuit 400 may have the filter circuit 52 omitted therefrom, and the power receiver circuit 500 may have the filter circuit 182 omitted therefrom.

[0060] FIG. 6 shows an example of a Double-LCC type wireless power transfer system. The power transmitter circuit 400 of such system includes an immittance filter as the filter circuit 52. The immittance filter includes a first inductor 54A connected in series to the power transmitter coil 22, a second inductor 54C connected in series to the first inductor 54A, and a capacitor 54B. The capacitor 54B is connected to the connection point between the first inductor 54A and the second inductor 54C. Further, the power transmitter circuit 400 also includes two series capacitors 23 as the power-transmitter resonant circuit 30, similar to that shown in FIG. 5.

[0061] The power receiver circuit 500 of the Double-LCC wireless power transfer system includes an immittance filter as the filter circuit 182. The immittance filter includes a first inductor 184A connected in series to the power receiver coil 102, a second inductor 184C connected in series to the first inductor 184A, and a capacitor 184B. The capacitor 184B is connected to a connection point between the first inductor 184A and the second inductor 184C. Further, the power receiver circuit 500 also includes two power-receiving resonant capacitors 141 as the power-receiver resonant circuit 140, similar to that shown in FIG. 5.

[0062] In the Double-LCC wireless power transfer system, the filter circuit 52 functions as an immittance converter, and therefore functions as a current source. Further, the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 function as immittance converters, thereby functioning as voltage sources. The filter circuit 182 functions as an immittance converter and thereby functioning as a current source. In such manner, a power source for (i) the rectifier circuit 200 and (ii) the high-voltage power storage battery 300 functioning as a voltage source serves as a current source.

[0063] Note that, in FIG. 6, the filter circuit 52 of the power transmitter circuit 400 does not have to be provided with the first inductor 54A on the power transmitter coil 22 side, and the function of the first inductor 54A may be substituted by the inductance of the power transmitter coil 22. Further, the filter circuit 182 of the power receiver circuit 500 does not have to be provided with the first inductor 184A on the power receiver coil 102 side, and the function of the first inductor 184A may be substituted by the inductance of the power receiver coil 102.

[0064] As illustrated in FIGs. 5 and 6, the rectifier circuit 200 functions as a current source. On the other hand, there are cases where multiple specifications are set for the power transmitter circuit 400 available on the market. Further, there may be multiple specifications for the power receiver circuit 500 available on the market. In such case, the combination of the output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 may be not an appropriate combination. FIG. 7 shows an example of an inappropriate combination in which the power transmitter circuit 400 is a Double-LCC type circuit and the filter circuit 182 of the power receiver circuit 500 is a band-pass filter instead of an immittance filter.

[0065] When the combination is not appropriate, the power transfer for the rectifier circuit 200 and the high-voltage power storage battery 300 may function as a voltage source, which may cause inconvenience. Specifically, when the output voltage of the rectifier circuit 200 is higher than that of the high-voltage power storage battery 300 during wireless power transfer, there is a concern that a large current will flow from the rectifier circuit 200 to the high-voltage power storage battery 300. Further, when the output voltage of the rectifier circuit 200 is lower than that of the high-voltage power storage battery 300 during wireless power transfer, there is a concern that the rectifier circuit 200 may not be able to supply electric current to the high-voltage power storage battery 300.

[0066] To address such a problem, the processor of the power transmitter controller 71 provided in each of the power-transmitter power source units 51 arranged on the ground side performs the process shown in FIG. 8. The process shown in FIG. 8 is performed when wireless power transfer is performed while the vehicle is parked. The power transfer during parking is a wireless power transfer from the power transmitter coil 22 provided in the parking space (specifically, for example, buried) to the power receiver coil 102 of the vehicle 11 when the power transmitter coil 22 and the power receiver coil 102 are facing each other in the vertical direction.

[0067] In step S10, the power transmitter controller 71 acquires, from the power receiver device 100 of the vehicle 11, information on the output characteristic of the power receiver circuit 500 included in the power receiver device 100 and vehicle ID information associated with such output characteristic.

[0068] For example, the power transmitter controller 71 acquires information on the output characteristic and ID information of the power receiver circuit 500 through narrow-area wireless communication using the power-receiver communication coil 170 and the power-transmitter communication coil 40. Specifically, the power receiver controller 231 includes information on the output characteristic of the power receiver circuit 500 and ID information in the vehicle-side signal. The power transmitter controller 71 acquires information on the output characteristic and ID information of the power receiver circuit 500 based on the signal received by the power-transmitter communication coil 40.

[0069] Further, for example, the power transmitter controller 71 acquires information on the output characteristic and ID information of the power receiver circuit 500 through the wide-area wireless communication or wired communication with the server 410 described above. Specifically, the server 410 transmits information on the output characteristic of the power receiver circuit 500 to the power transmitter controller 71 in association with the ID information. The power transmitter controller 71 associates the received information on the output characteristic with the ID information, and stores the information in the storage unit. The power transmitter controller 71 acquires information on the output characteristic of the power receiver circuit 500 to which supply power is wirelessly going to be performed based on the ID information grasped from the received signal of the power-transmitter communication coil 40 and the information on the output characteristic stored in the storage unit.

[0070] Subsequently in step S11, the power transmitter controller 71 determines whether the power-transmitter communication coil 40 has received a power transfer request signal. When it is determined that the power transfer request signal has been received, the power transmitter controller 71 determines that there is a power transfer request, and proceeds to step S12. In step S12, the power transmitter controller 71 acquires information on the requested power Weq and the ID information of the vehicle 11 based on the received power transfer request signal.

[0071] Subsequently in step S13, the power transmitter controller 71 determines whether the output characteristic of the power transmitter circuit 400 controlled thereby and the output characteristic of the power receiver circuit 500 acquired in step S10 are an appropriate combination. Specifically, for example, when it is determined that the number of immittance converters included in the power receiver circuit 500 and the power transmitter circuit 400 is an odd number in total, the power transmitter controller 71 determines that the combination is appropriate. On the other hand, when the power transmitter controller 71 determines that the total number of immittance converters included in the power receiver circuit 500 and the power transmitter circuit 400 is an even number, it determines that the combination is not appropriate.

[0072] When the power transmitter controller 71 determines that the combination is not appropriate, the process proceeds to step S14, where energization to the power transmitter coil 22 is prevented, thereby preventing wireless power transfer to the vehicle 11.

[0073] Further, the power transmitter controller 71 transmits target identification information, which is the ID information of the vehicle 11 (hereinafter referred to as the target vehicle) that has been determined as an inappropriate combination, to each of the other power-transmitter control unit 70, for example, via wide-area wireless communication or wired communication. In such manner, the target identification information is shared among the power transmitter controllers 71. Among the power transmitter controllers 71 that have received the target identification information, the power transmitter controller 71, which had determined that the combination of the output characteristic of the power transmitter circuit 400 controlled thereby and the output characteristic of the power receiver circuit 500 provided in the target vehicle is not an appropriate combination, performs a process shown in FIG. 9.

[0074] Specifically, in step S20, the power transmitter controller 71 determines whether the target identification information has been received.

[0075] When it is determined that the target identification information has been received, the power transmitter controller 71 proceeds to step S21, and prevents wireless power transfer to the power receiver coil 102 provided in the target vehicle identified by the target identification information. That is, even when the power transmitter controller 71 receives a power transfer request signal from the power-receiver communication coil 170 provided in the target vehicle that is parked, the power transmitter controller 71 does not energize the power transmitter coil 22 that is the control target of the power transmitter controller 71 itself. In such manner, it is possible to reliably prevent wireless power transfer to the target vehicle that is not an appropriate combination.

[0076] Returning to the description of FIG. 8, when the power transmitter controller 71 determines in step S13 that the combination is appropriate, the process proceeds to step S15, where the power transmitter controller 71 starts a temporary power transfer process. The temporary power transfer process may also be called as a tracking process.

[0077] In the temporary power transfer process, the power transmitter controller 71 calculates a phase difference of electric current with respect to an application voltage to the power transmitter coil 22, while setting the frequency of the application voltage to the power transmitter coil 22 to multiple, respectively different frequencies. Thereafter, from among the multiple frequencies of the set application voltage, the power transmitter controller 71 sets a frequency at which the calculated phase difference falls below a phase difference threshold value to the frequency of the electric current flowing through the power transmitter coil 22.

[0078] The temporary power transfer process is started on condition that it is determined that a combination of the output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 is an appropriate combination. In such manner, an occurrence of a situation is preventable, in which power transfer control of the power transmitter coil 22 for wireless power transfer is started in an inappropriate combination.

[0079] Note that, as the phase difference threshold value in the temporary power transfer process, for example, a value at which the efficiency of power transfer from the power transmitter coil 22 to the power receiver coil 102 becomes larger than a predetermined efficiency may be set in advance based on tests or simulations. Also, the power transmitter controller 71 may calculate the phase difference based on, for example, a detected value of a current sensor that detects an electric current flowing through the power transmitter coil 22 and a detected value of a voltage sensor that detects the voltage of the power transmitter coil 22.

[0080] Subsequently in step S16, the power transmitter controller 71 once again determines whether the output characteristic of the power transmitter circuit 400 controlled thereby and the output characteristic of the power receiver circuit 500 acquired in step S10 are an appropriate combination. When the power transmitter controller 71 determines that the combination is not appropriate, the process proceeds to step S14.

[0081] Even when the combination is not appropriate, it may be erroneously determined in step S13 that the combination is an appropriate combination due to, for example, the influence of noise on the acquired output characteristic information. Therefore, the process of step S16 is provided. When the combination is determined as not an appropriate one in the second determination, the temporary power transfer process is stopped. As a result, it is possible to suitably prevent the occurrence of a situation in which the power transfer control of the power transmitter coil 22 for wireless power transfer is continuously performed in an inappropriate combination state.

[0082] On the other hand, when the power transmitter controller 71 determines in step S51 that the combination is appropriate, the process proceeds to step S17. In step S17, the power transmitter controller 71 determines whether a relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 provided in the parked vehicle 11 is appropriate during performing of the temporary power transfer process. Examples of such determination method will be described in the following.

[0083] For example, during performing the temporary power transfer process, the power transmitter controller 71 determines whether the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is appropriate by comparing a magnitude of the electric current flowing through the power transmitter coil 22 or its correlation value with a threshold value. For example, when the power transmitter circuit 400 and the power receiver circuit 500 are of the SS type shown in FIG. 5, the power transmitter controller 71 may determine that the positional relationship is appropriate on determining that the magnitude of the electric current flowing through the power transmitter coil 22 (specifically, a peak value of the electric current) exceeds a threshold value. The magnitude of the electric current may be calculated based on the detected value of a current sensor that detects the electric current flowing through the power transmitter coil 22.

[0084] For example, the power transmitter controller 71 calculates a ratio (Pout / Pin) of an output power Pout (effective power) of the inverter 60 to an input power Pin (apparent power) from the PFC circuit 61 to the inverter 60, and determines that the positional relationship is appropriate when the calculated ratio exceeds a predetermined ratio. Such a determination method is based on a consideration that as the relative positional relationship approaches the appropriate positional relationship, the coupling coefficient between the power transmitter coil 22 and the power receiver coil 102 increases, and the ratio becomes larger. Note that, the power transmitter controller 71 may, for example, calculate the above-described ratio based on the detected values from current and voltage sensors that detect the input current and input voltage to the inverter 60, as well as the detected values from current and voltage sensors that detect the output current and output voltage of the inverter 60. Further, in the determination process of step S17, other parameters such as a detected value of an electric current flowing through the power transmitter coil 22 may also be used in addition to the electric power.

[0085] On the other hand, when the power transmitter controller 71 determines that the positional relationship is appropriate, the process proceeds to step S18, and starts a regular power transfer process. The regular power transfer process is a process in which (a) the electric power transmitted to the power receiver coil 102 is increased compared to the temporary power transfer process, and (b) switching control of the PFC circuit 61 and the inverter 60 is performed to supply electric current to the power transmitter coil 22 for setting the frequency of the output voltage of the inverter 60 to the frequency set in the temporary power transfer process in step S15.

[0086] During the temporary power transfer process, a determination is again made as to whether the combination of the output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 is an appropriate combination. In such manner, the regular power transfer process is prevented from being started with an inappropriate combination. As a result, for example, it is possible to prevent an overcurrent from flowing through the high-voltage power storage battery 300.

[0087] On the other hand, when the power transmitter controller 71 determines in step S17 that the positional relationship is not appropriate, the process proceeds to step S19, and performs a notification process. Such a process is a process of notifying the vehicle 11 that the relative positional relationship described above has to be adjusted to an appropriate positional relationship. Specifically, for example, the notification process is a process of notifying a driver of the vehicle 11 by means of a display or voice on the navigation device 331 of the vehicle 11 to adjust the relative positional relationship. After completing the process of step S19, the power transmitter controller 71 proceeds to step S17, and determines again whether the relative positional relationship is an appropriate one.

[0088] There may be a case that that the combination of the acquired output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 is determined as not an appropriate combination in steps S13 or S17, due to the relative positional relationship of the power receiver coil 102 with respect to the power transmitter coil 22 is not appropriate when the vehicle 11 is stopped. Therefore, the notification process in step S19 is provided. After the notification process is performed, the relative positional relationship is adjusted to an appropriate positional relationship, for example, by the driver’s operation of the vehicle or by automatic steering control of the vehicle 11. In such case, in the re-determination in step S17, it may possibly be determined that the acquired combination of the output characteristic of the power receiver circuit 500 and the output characteristic of the power transmitter circuit 400 is an appropriate combination.

[0089] In such manner, the notification process can eliminate the occurrence of erroneous determinations caused by the relative positional relationship of the power receiver coil 102 with respect to the power transmitter coil 22 deviating from the appropriate positional relationship.

[0090] <Second Embodiment> The second embodiment will be described in the following with reference to the drawings mainly in terms of differences from the first embodiment. In the present embodiment, the process shown in FIG. 10, which includes the process of determining whether the combination is appropriate, is performed while the vehicle is traveling.

[0091] The process of steps S30 to S37 is the same as that of steps S10 to S13 and S15 to S18 shown in FIG. 18. In step S36, the power transmitter controller 71 determines whether the relative positional relationship between the power transmitter coil 22 that is the control target of the power transmitter controller 71 itself and the power receiver coil 102 of the vehicle 11 traveling near the power transmitter coil 22 that is controlled by the power transmitter controller 71 itself is appropriate. When the power transmitter controller 71 determines that the positional relationship is not appropriate, the process proceeds to step S38, where the power transmitter controller 71 prevents the supply of electric power to the power transmitter coil 22, thereby preventing wireless power transfer to the vehicle 11 while the vehicle 11 is traveling.

[0092] In step S33 or S35, the power transmitter controller 71 determines whether the output characteristic of the power transmitter circuit 400 controlled thereby and the output characteristic of the power receiver circuit 500 acquired in step S30 are an appropriate combination. When it is determined that the combination is not appropriate, the power transmitter controller 71 proceeds to step S39, and transmits count information to each of the other power-transmitter control units 70 by, for example, wide-area wireless communication or wired communication. The count information is information indicating that the combination is not appropriate, and is information associated with the ID information of the vehicle 11 (hereinafter, target identification information) acquired in step S32. The count information is shared among the power transmitter controllers 71. Thereafter, the power transmitter controller 71 proceeds to step S38.

[0093] FIG. 11 is a flowchart of a process performed by the power transmitter controller 71.

[0094] In step S40, the power transmitter controller 71 increments by one a total number of determinations Ntotal associated with the target identification information included in the received count information every time the power transmitter controller 71 receives the count information. That is, every time a negative determination is made in step S33 or S35 of FIG. 10 for a target vehicle identified by the target identification information, the total number of determinations Ntotal associated with the target vehicle is incremented by one. Note that, when the power transmitter controller 71 from itself transmits the count information, the power transmitter controller 71 increments the total number of determinations Ntotal by one every time the power transmitter controller 71 transmits the count information.

[0095] Subsequently in step S41, the power transmitter controller 71 determines whether a period until the counted total number of determinations Ntotal reaches a number threshold value Nth is shorter than a determination period Tth.

[0096] When the power transmitter controller 71 determines that the above-described period is shorter than the determination period Tth, the power transmitter controller 71 proceeds to step S42, and prevents wireless power transfer to the power receiver coil 102 provided in the target vehicle. That is, even when the power transmitter controller 71 receives a power transfer request signal from the power-receiver communication coil 170 provided in the target vehicle while the vehicle is traveling, the power transmitter controller 71 does not energize the power transmitter coil 22 that is the control target of the power transmitter controller 71 itself.

[0097] A target vehicle whose period until the total number of determinations Ntotal reaches the number threshold value Nth is shorter than the determination period Tth is a vehicle that passes over many power-transmitter coil units 21 in a short period of time, and may be a vehicle traveling at an excessively high speed. It is thus not preferable for such vehicles to continue traveling. In other words, it is not desirable to perform wireless power transfer to the target vehicle. According to the processes shown in FIGs. 10 and 11, wireless power transfer to a vehicle traveling at an excessively high speed is preventable.

[0098] <Other Embodiments> The above-described embodiments may be changed and carried out as follows.

[0099] The wireless power transfer system may have a second function of supplying electric power in a wireless manner from a vehicle-side device to a ground-side device, in addition to a first function of supplying electric power in a wireless manner from a ground-side device to a vehicle-side device. In such case, the power receiver device 100 on the vehicle side has a power-transmitter function in addition to a power receiving function. The power transmitter device 20 on the ground side has a power receiving function in addition to a power-transmitter function. The second function will be described in the following with reference to FIG. 3.

[0100] The power receiver controller 231 applies a high-frequency AC voltage to the power receiver coil 102 by the switching control of the rectifier circuit 200. Therefore, a high-frequency electric current flows through the power receiver coil 102, and a magnetic field for power-transmitter is generated in the power receiver coil 102.

[0101] When the magnetic field generated in the power receiver coil 102 interlinks with the power transmitter coil 22, a high-frequency electric current that fluctuates at the frequency of the high-frequency electric current energizing the power receiver coil 102 flows through the power transmitter coil 22. The high-frequency electric current energizing 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 such case, the power transmitter controller 71 performs the switching control of the inverter 60 and the PFC circuit 61.

[0102] Note that, in the wireless power transfer system having the second function, for example, the power transmitter device 20 may at least include a transmitter that supplies a power transfer request signal to the power-transmitter communication coil 40. Further, the power receiver device 100 may include a receiver that receives the power transfer request signal received by the power-receiver communication coil 170 and inputs the signal to the power receiver controller 231.

[0103] The wireless power transfer system may have a function of supplying electric power in a wireless manner from a vehicle-side device to a ground-side device, instead of the function of supplying electric power in a wireless manner from a ground-side device to a vehicle-side device.

[0104] The power-receiving communication antenna and the power-transmitter communication antenna are not limited to communication coils, and various antennas may also be used. For example, the communication antenna is a dipole antenna or a monopole antenna.

[0105] The method of wireless power-transmitter by the power transmitter antenna and the power receiver antenna is not limited to the magnetic field resonance method, and may also be an electric field coupling method. In such case, a power transmitter antenna and a power receiver antenna that are different in form from coils and that use an electric field coupling method may be used.

[0106] The vehicle identification information used in the processing of the above-described embodiments is not limited to vehicle ID information, and may also be, for example, a token or credit card information of a vehicle user.

[0107] The vehicle on which the power receiver device 100 is mounted is not limited to a vehicle that travels on the road RS, and may also be, for example, an automated guided vehicle (AGV) or a driving robot. In such case, the power-transmitter coil unit 21 does not have to be buried in the road RS, but may also be installed on a sidewalk adjacent to the road RS, in a parking lot, or on a route along which the AGV travels.

[0108] The control units and methods thereof described in the present disclosure may be implemented by a dedicated computer including a processor programmed to perform one or more functions embodied by a computer program and a memory. Alternatively, the control units and the methods thereof described in the present disclosure may also be implemented by a dedicated computer including a processor with one or more dedicated hardware logic circuits. Alternatively, the control units and method thereof described in the present disclosure may also be implemented using one or more dedicated computers constituted by a combination of the processor and the memory programmed to perform one or more functions and the processor with one or more hardware logic circuits. The computer program may also be stored on a computer-readable and non-transitory, tangible storage medium as an instruction executed by a computer.

[0109] The present disclosure is described based on the examples, and it is understood that present disclosure is not limited to the embodiments or the structures. The present disclosure includes various modification examples and modifications within the equivalent scope. Although various combinations and forms are set forth in the present disclosure, other combinations and configurations, including only one element, more, or less, are also intended to fall within the scope and spirit of the present disclosure.

Claims

1. A power transmitter device applicable to a wireless power transfer system (10), in which one of a ground side device on a ground and a vehicle side device on a vehicle (11) is a power transmitter device (20) including a power transmitter antenna (22) and an other of the ground side device and the vehicle side device is a power receiver device (100) including a power receiver antenna (102), for transmission of electric power in a wireless manner to the power receiver antenna by supplying electric power to the power transmitter antenna, the power receiver device including a power receiver circuit (500) including the power receiver antenna, the power transmitter device comprising: a power transmitter circuit (400) including the power transmitter antenna; and a power-transmitter control unit (70) configured to perform power transfer control of the power transmitter circuit for wireless power transfer, wherein the power-transmitter control unit is configured to acquire an output characteristic of the power receiver circuit, determine whether a combination of the output characteristic as acquired and an output characteristic of the power transmitter circuit is an appropriate combination, and start the power transfer control of the power transmitter circuit when determining that the combination is the appropriate combination.

2. The power transmitter device according to claim 1, wherein the power-transmitter control unit is configured to after starting the power transfer control of the power transmitter circuit, re-determine whether the combination of the output characteristic as acquired and the output characteristic of the power transmitter circuit is the appropriate combination by using a method different from a method used for determining whether the combination is the appropriate combination before starting the power transfer control, and continue the power transfer control of the power transmitter circuit when re-determining that the combination is the appropriate combination.

3. The power transmitter device according to claim 2, wherein the power receiver device is configured to transmit a power transfer request signal for requesting power transfer to the power transmitter device, the power-transmitter control unit is configured to start a temporary power transfer process for temporarily supplying electric power to the power transmitter antenna when determining that there is a power transfer request based on the power transfer request signal as received and that the combination is the appropriate combination, after starting the temporary power transfer process, re-determine whether the combination is the appropriate combination, when re-determining that the combination is the appropriate combination, determine, during the temporary power transfer process, whether a relative positional relationship between the power transmitter antenna and the power receiver antenna is an appropriate positional relationship, and when determining that the relative positional relationship is the appropriate positional relationship, perform a regular power transfer process in which electric power transmitted from the power transmitter antenna is greater than the electric power in the temporary power transfer process.

4. The power transmitter device according to claim 3, wherein the power-transmitter control unit is configured to perform, after starting the temporary power transfer process, a notification process for notifying the vehicle that the relative positional relationship has to be adjusted to the appropriate positional relationship when determining, while the vehicle is stopped, that the relative positional relationship is not the appropriate positional relationship.

5. The power transmitter device according to any one of claims 1 to 4, wherein the power transmitter device is a ground side device, the power-transmitter control unit is provided for a predetermined number of power-transmitter communication antennas, the power-transmitter control unit is any of power-transmitter control units and is configured to, when determining that the combination is not the appropriate combination in re-determination, transmit identification information of the vehicle, which is not in the appropriate combination, to an other of the power-transmitter control units, and each of the power-transmitter control units is configured not to perform wireless power transfer to the power receiver antenna of the vehicle, which is identified by the identification information as received.

6. The power transmitter device according to claim 2, wherein the power transmitter device is provided as a ground side device, the power-transmitter control unit is provided for a predetermined number of power-transmitter communication antennas, and the power-transmitter control unit is any of power-transmitter control units and is configured to count a number of determination that the combination is not the appropriate combination in association with identification information of the vehicle, and when determining that a period, in which a total number of determination as counted in the power-transmitter control units reaches a number threshold value, is shorter than a determination period, not to perform the wireless power transfer to the power receiver antenna of the vehicle in which the total number of determination as counted reaches the number threshold value.

7. A program applicable to a wireless power transfer system (10), in which one of a ground side device on a ground and a vehicle side device on a vehicle (11) is a power transmitter device (20) including a power transmitter antenna (22) and an other of the ground side device and the vehicle side device is a power receiver device (100) including a power receiver antenna (102), for transmission of electric power in a wireless manner to the power receiver antenna by supplying electric power to the power transmitter antenna, the power receiver device including a power receiver circuit (500) including the power receiver antenna, the power transmitter device including a power transmitter circuit (400) including the power transmitter antenna, the program comprising instructions to cause a processor to execute: a process to acquire an output characteristic of the power receiver circuit; a process to determine whether a combination of the output characteristic as acquired and an output characteristic of the power transmitter circuit is an appropriate combination; and a process to start power transfer control of the power transmitter circuit when determining that the combination is the appropriate combination.

8. A control method applicable to a wireless power transfer system (10), in which one of a ground side device on a ground and a vehicle side device on a vehicle (11) is a power transmitter device (20) including a power transmitter antenna (22) and an other of the ground side device and the vehicle side device is a power receiver device (100) including a power receiver antenna (102), for transmission of electric power in a wireless manner to the power receiver antenna by supplying electric power to the power transmitter antenna, the power receiver device including a power receiver circuit (500) including the power receiver antenna, the power transmitter device including a power transmitter circuit (400) including the power transmitter antenna, the control method comprising: acquiring, by a processor in a process, an output characteristic of the power receiver circuit; determining, by the processor in a process, whether a combination of the output characteristic as acquired and an output characteristic of the power transmitter circuit is an appropriate combination; and starting, by the processor in a process, power transfer control of the power transmitter circuit when determining that the combination is the appropriate combination.

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