Power transmitter device, wireless power transfer system, power transmission program, and control method for power transmitter device

Abstract

A power transmitter side control unit (70) of a power transmitter device (20) energizes a power transmitter antenna on condition that it is determined that there is a power supply request based on a power supply request signal received by a power transmitter side communication antenna (40), searches for a suitable frequency of a voltage applied to the power transmitter antenna at which an energized state of the power transmitter antenna satisfies a predetermined condition in a predetermined frequency range including a predetermined resonance frequency of a wireless power transfer system including a power transmitter antenna (22) and a power receiver antenna (102), and sets the suitable frequency to a frequency of a current flowing through the power transmitter antenna when it is determined that there is a suitable frequency, and stops energizing the power transmitter antenna when it is determined that there is no suitable frequency.　 On the other hand, the power transmitter side control unit narrows the predetermined frequency range when a traveling speed is lower than a predetermined speed based on a traveling speed signal, compared to when the traveling speed is not lower than the predetermined speed.

Description

POWER TRANSMITTER DEVICE, WIRELESS POWER TRANSFER SYSTEM, POWER TRANSMISSION PROGRAM, AND CONTROL METHOD FOR POWER TRANSMITTER DEVICECross Reference

[0001] This application is based on Japanese Application No. 2024-208019 filed on November 29, 2024, the contents of which are incorporated herein by reference.

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

[0003] A system for wireless power transfer from a power transmitter device on the ground side to a power receiver device mounted on an electric vehicle while the vehicle is parked is disclosed.　 In order to appropriately supply power in a wireless manner from a power transmitter coil of the power transmitter device to a power receiver coil of the power receiver device, the relative positional relationship between the power transmitter coil and the power receiver coil is required to be an appropriate relationship.　 Patent Literature describes an automatic parking assistance control for adjusting the relative positional relationship between the power transmitter coil and the power receiver coil to an appropriate positional relationship.

[0004] JP2021-154837A

[0005] Due to some factors, such as the driver performing a manual driving operation while the automatic parking assistance control is being executed, a vehicle may park with the relative positional relationship between the power transmitter coil (power transmitter antenna) and the power receiver coil (power receiver antenna) deviating from an appropriate positional relationship.　 In this case, when wireless power transfer from the power transmitter coil to the power receiver coil is started, there is a risk that power supply will continue when an increased leakage magnetic field and a decreased power supply efficiency occur.　 This situation is not limited to when a vehicle is parked, but is also common when a vehicle is stopped.

[0006] A primary object of the present disclosure is to prevent power supply from continuing in a state in which the relative positional relationship between the power transmitter antenna and the power receiver antenna deviates from an appropriate positional relationship.

[0007] According to a first aspect of the disclosure, a power transmitter device is to be applied to a wireless power transfer system including the power transmitter device and a power receiver device. 　The power transmitter device comprises: a power transmitter antenna; a power transmitter side control unit configured to supply power in a wireless manner from the power transmitter antenna to a power receiver antenna of the power receiver device mounted on a vehicle and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna; and a power transmitter side communication antenna.　 The power receiver device includes a power receiver side communication antenna for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna.　 The power transmitter side control unit is configured to energize the power transmitter antenna when determining that there is power supply request based on the power supply request signal received by the power transmitter side communication antenna, search for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna, set a frequency of a current flowing through the power transmitter antenna to the suitable frequency when determining that there is the suitable frequency, stop energizing of the power transmitter antenna when determining that there is no suitable frequency, and based on the traveling speed signal received by the power transmitter side communication antenna, narrow the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

[0008] According to the above configuration, the power transmitter device includes a power transmitter antenna, and supplies power from the power transmitter antenna to a power receiver antenna of the power receiver device mounted on a vehicle in a wireless manner.　 The power receiver device supplies, to a power receiver side communication antenna, a power supply request signal indicating a power supply request to the power transmitter antenna, and a traveling speed signal indicating the traveling speed of a vehicle.　 The power transmitter side control unit energizes the power transmitter antenna when it is determined that there is a power supply request based on the power supply request signal received by the power transmitter side communication antenna.　 In this case, as the frequency of a current flowing through the power transmitter antenna deviates from a predetermined resonance frequency of a wireless power transfer system having the power transmitter antenna and the power receiver antenna, the power to be supplied to the power transmitter antenna when transmitting a predetermined power becomes larger, and the power supply efficiency decreases.　 The resonance frequency of the wireless power transfer system changes depending on whether the relative positional relationship between the power transmitter antenna and the power receiver antenna is an appropriate relationship.

[0009] The power transmitter side control unit searches for a suitable frequency, which is the frequency of the applied voltage of the power transmitter antenna at which the energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of a wireless power transfer system having the power transmitter antenna and the power receiver antenna, and when it is determined that there is the suitable frequency, sets the suitable frequency to the frequency of the current flowing through the power transmitter antenna.　 Therefore, the power supplied to the power transmitter antenna when transmitting predetermined power is reduced, and power supply efficiency can be improved.　 In response to this, the power transmitter side control unit stops energization to the power transmitter antenna when it is determined that there is no suitable frequency.　 Therefore, it is possible to stop supplying power when there is no suitable frequency, that is, when an increased leakage magnetic field and a decreased power supply efficiency occur.

[0010] The power transmitter side control unit narrows the predetermined frequency range when the traveling speed is lower than a predetermined speed, based on the traveling speed signal received by the power transmitter side communication antenna compared to when the traveling speed is not lower than the predetermined speed.　 Therefore, when the traveling speed of the vehicle is lower than the predetermined speed and there is a higher possibility of parking or stopping than when the traveling speed of the vehicle is not lower than the predetermined speed, power supply is more likely to be stopped when an increased leakage magnetic field and a decreased power supply efficiency occur.　 Therefore, it is possible to prevent power supply from continuing in a state in which the relative positional relationship between the power transmitter antenna and the power receiver antenna deviates from an appropriate positional relationship.

[0011] According to a second aspect of the disclosure, a power transmission program is for controlling a power transmitter device to be applied to a wireless power transfer system.　 The wireless power transfer system includes a power transmitter device and a power receiver device.　 The power transmitter device includes a power transmitter antenna, a power transmitter side control unit configured to supply power in a wireless manner from the power transmitter antenna to the power receiver antenna of the power receiver device mounted on a vehicle and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna, and a power transmitter side communication antenna.　 The power receiver device includes a power receiver side communication antenna for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna.　 The program is configured to cause the power transmitter side control unit to execute processing comprising: energizing the power transmitter antenna when determining that there is power supply request based on the power supply request signal received by the power transmitter side communication antenna; searching for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna; setting, when determining that there is the suitable frequency, a frequency of a current flowing through the power transmitter antenna to the suitable frequency; stopping, when determining that there is no suitable frequency,　 energizing of the power transmitter antenna; and narrowing, based on the traveling speed signal received by the power transmitter side communication antenna, the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

[0012] According to the above configuration, in the power transmission program for controlling the power transmitter device, it is possible to achieve the same effect as the first aspect.

[0013] According to a third aspect of the disclosure, a control method is for a power transmitter device to be applied to a wireless power transfer system. 　The wireless power transfer system includes a power transmitter device and a power receiver device. 　The power transmitter device includes a power transmitter antenna, a power transmitter side control unit configured to supply power in a wireless manner from the power transmitter antenna to a power receiver antenna of the power receiver device mounted on a vehicle and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna, and a power transmitter side communication antenna. 　The power receiver device includes a power receiver side communication antenna for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna.　 The method comprises: causing the power transmitter side control unit to execute processing of energizing the power transmitter antenna, when determining that there is power supply request based on the power supply request signal received by the power transmitter side communication antenna, searching for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna, setting, when determining that there is the suitable frequency, a frequency of a current flowing through the power transmitter antenna to the suitable frequency, stopping, when determining that there is no suitable frequency, energizing of the power transmitter antenna, and narrowing, based on the traveling speed signal received by the power transmitter side communication antenna, the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

[0014] According to the above configuration, in the power transmitter device control method, it is possible to achieve the same effect as the first aspect.

[0015] 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.

[0016] FIG. 1 is an overall configuration diagram of a wireless power transfer system.FIG. 2 is a diagram showing the wireless power transfer system and a vehicle.FIG. 3 shows a power transmitter device and a power receiver device.FIG. 4 is a diagram showing a power receiver side control unit and a peripheral configuration thereof.FIG. 5 is a diagram showing a power transmitter side control unit and a peripheral configuration thereof.FIG. 6 is a diagram showing a case in which the relative positional relationship between a power transmitter coil and a power receiver coil is an appropriate positional relationship.FIG. 7 is a diagram showing an example of a case in which the relative positional relationship between the power transmitter coil and the power receiver coil is not an appropriate positional relationship.FIG. 8 is a diagram showing another example of a case in which the relative positional relationship between the power transmitter coil and the power receiver coil is not an appropriate positional relationship.FIG. 9 is a diagram showing the relative positional relationship between the power transmitter coil and the power receiver coil, and the relationship between a frequency of an applied voltage, a supplied power, and a phase difference.FIG. 10 is a flowchart showing energization control of the power transmitter coil.FIG. 11 is a diagram showing the relationship between a traveling speed and a predetermined frequency range.FIG. 12 is a diagram showing a modification example of the relationship between a traveling speed and a predetermined frequency range.FIG. 13 is a diagram showing another modification example of the relationship between a traveling speed and a predetermined frequency range.FIG. 14 is a diagram showing another modification example of the relationship between a traveling speed and a predetermined frequency range.FIG. 15 is a diagram showing an SS-type of wireless power transfer method.FIG. 16 is a diagram showing an SP-type of wireless power transfer method.FIG. 17 is a diagram showing a PS type of wireless power transfer method.FIG. 18 is a diagram showing a PP type wireless power transfer method.

[0017] Embodiments and modification examples will be described with reference to the drawings.　 In the embodiments and modification examples, functionally and / or structurally corresponding and / or related portions may be denoted by the same reference numerals.　 For corresponding and / or related portions, reference may be made to the descriptions of other embodiments and other modification examples.

[0018] An embodiment of a wireless power transfer system according to the present disclosure will be described below with reference to the drawings.

[0019] First, the 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 traveling 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 (including parked), power is supplied from the power transmitter device 20 to the power receiver device 100.　 The wireless power transfer system 10 performs wireless power transfer 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 called a dynamic wireless power transfer (D-WPT) system.

[0020] The power transmitter device 20 is a device on the ground side including a power transmitter side coil unit 21 and a power transmitter side power source unit 51 that supplies power to the power transmitter side coil unit 21.　 The power transmitter device 20 is, for example, a stationary device.　 The power transmitter side coil unit 21 (also referred to as "GA") is installed (for example, buried) on the road RS, a parking lot, or the like.　 The power transmitter side power source unit 51 (also referred to as "MU") is installed, for example, at the side of the road RS.　 The power transmitter side coil unit 21 is connected to a power transmitter side power source unit 51.　 The power transmitter side 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 side coil unit 21.　 The AC power source 15 is, for example, a commercial power source.　 A plurality of power transmitter side coil units 21 are disposed along the lanes of the road RS.　 FIG. 2 shows an example in which four power transmitter side coil units 21 disposed side by side along the road RS are connected to one power transmitter side power source unit 51.　 In other words, one power transmitter side power source unit 51 is provided for each of the four power transmitter side coil units 21.　 The configuration is not limited to one power transmitter side power source unit 51 being provided for each of the multiple power transmitter side coil units 21, but may also be one power transmitter side power source unit 51 being provided for one power transmitter side coil unit 21.　 A power transmitter coil 22 of the power transmitter side coil unit 21 installed in a parking lot corresponds to a first power transmitter antenna, and the power transmitter coil 22 of the power transmitter side coil unit 21 installed on the road RS corresponds to a second power transmitter antenna.

[0021] The power transmitter side power source unit 51 includes a PFC circuit 61, an inverter 60, and a filter circuit 52.　 The PFC circuit 61 includes an AC / DC converter and is connected to the AC power source 15.　 The switching of the switching elements (for example, IGBTs or MOSFETs) included in the PFC circuit 61 is controlled so that the power factor of the AC power input from the AC power source 15 is improved and the input AC power is converted into DC power.

[0022] 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.

[0023] The filter circuit 52 removes noise contained in the AC current input from the inverter 60, and supplies the AC current from which the noise has been removed to the power transmitter side coil unit 21.　 The filter circuit 52 is, for example, an LC filter including a coil and a capacitor.　 As the filter circuit 52, circuits of various configurations are used, specifically, for example, a T-type filter circuit is used.

[0024] The power transmitter side coil unit 21 includes a power transmitter coil 22 (corresponding to a power transmitter antenna), a power transmitter side resonant circuit 30, and a power transmitter side communication antenna 40.　 The power transmitter side resonant circuit 30 supplies the AC power supplied from the filter circuit 52 to the power transmitter coil 22.　 As the power transmitter side resonant circuit 30, various well-known resonant circuits such as a circuit including a resonance capacitor can be used.

[0025] The power receiver device 100 includes a power receiver side coil unit 101 and a power receiver side power source unit 181.　 The power receiver side coil unit 101 includes a power receiver coil 102 (corresponding to a power receiver antenna).　 The power receiver side coil unit 101 is provided at the bottom of the vehicle body of the vehicle 11.　 When the vehicle 11 travels on the road RS in which the power transmitter coil 22 is buried, the power transmitter coil 22 on the ground side and the power receiver coil 102 provided on the vehicle 11 face each other in a vertical direction.

[0026] The power receiver device 100 includes a power receiver side resonant circuit 140.　 The power receiver coil 102 is connected to the power receiver side resonant circuit 140.　 Power is transmitted to the power receiver coil 102 from the power transmitter coil 22.　 The power receiver coil 102 supplies the received power to the power receiver side resonant circuit 140.　 As the power receiver side resonant circuit 140, various well-known resonant circuits such as a circuit including a resonance capacitor can be used.

[0027] The power receiver device 100 includes a filter circuit 182, a rectifier circuit 200 that functions as a DC / AC convertor circuit, and a smoothing capacitor 210.　 The filter circuit 182 removes noise contained in the AC current input from the power receiver side 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 including a reactor and a capacitor.

[0028] 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 the low potential side output terminal of the rectifier circuit 200.　 The rectifier circuit 200 is also called an electronic rectification box (ERB).

[0029] The vehicle 11 includes a high-potential side main switch 301H, a low-potential side main switch 301L, and a high-voltage power storage battery 300 as a power storage unit.　 The high-potential side main switch 301H and the low-potential side main switch 301L are, for example, relays (specifically, mechanical relays).　 The high potential side output terminal of the rectifier circuit 200 is connected to the positive-electrode terminal of the high-voltage power storage battery 300 via the high-potential side main switch 301H.　 The low potential side output terminal of the rectifier circuit 200 is connected to the negative terminal of the high-voltage power storage battery 300 via the low-potential side main switch 301L.　 The high-voltage power storage battery 300 is a secondary battery that can 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 power storage battery or a nickel-metal hydride power storage battery.

[0030] The vehicle 11 includes a driving inverter 310 and a rotating electric machine 320.　 The driving inverter 310 is a three-phase inverter, and is connected to the high-voltage power storage battery 300 via the high-potential side main switch 301H and the low-potential side main switch 301L.　 An armature winding of the rotating electric machine 320 is connected to the upper and lower arm switches constituting the driving inverter 310.　 With the high-potential side main switch 301H and the low-potential side main switch 301L turned on, the switching of the upper and lower arm switches of the driving inverter 310 is controlled such that the driving inverter 310 converts the DC power supplied from the high-voltage power storage battery 300 into AC power and supplies the AC power to the armature winding. 　This causes the rotor of the rotating electric machine 320 to rotate, and the drive wheels of the vehicle 11 are rotated by the rotational power of the rotor.　 As a result, the vehicle 11 travels.

[0031] As shown in FIG. 3, the power transmitter side power source unit 51 constituting the power transmitter device 20 includes a power transmitter side control unit 70.　 The power transmitter side control unit 70 includes a power transmitter side controller 71.　 The power transmitter side controller 71 is an electronic control unit (ECU) that performs various controls of the power transmitter device 20, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and the storage unit.

[0032] The storage unit includes memory and storage as hardware.　 The memory is a storage device for storing data used in the processing of the power transmitter side 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, a HDD or a flash memory.　 The storage stores program information and the like for the processing described below.

[0033] The power receiver device 100 includes a power receiver side power source unit 181 (also referred to as "WPU") having a power receiver side controller 231.　 The power receiver side 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 memory and storage as hardware.　 The memory is a storage device for storing data used in the processing of the power receiver side 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, a HDD or a flash memory.　 The storage stores program information and the like for the processing described below.

[0035] For example, program information stored in a non-transitory tangible storage medium is installed in the storage units of the power receiver side controller 231 and the power transmitter side controller 71.　 The storage medium is, for example, a USB memory, a CD-ROM, or a DVD.　 For example, program information transmitted via a communication network, such as over the air (OTA), is installed in the storage unit.

[0036] The power transmitter side 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.　 Therefore, a high-frequency current flows through the power transmitter coil 22, and a magnetic field for power transmission is generated in the power transmitter coil 22.

[0037] In the present embodiment, the power transmitter side 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.　 A predetermined resonance frequency f0, which is the resonance frequency of the power transmitter side resonant circuit 30 and the power receiver side resonant circuit 140, is set to the same frequency as the first specified frequency or to a frequency close to the first specified frequency.　 That is, the predetermined resonance frequency f0 of a wireless power transfer system having the power transmitter coil 22, the power transmitter side resonant circuit 30, the power receiver coil 102, and the power receiver side resonant circuit 140 is set to the same frequency as the first specified frequency or to a frequency close to the first specified frequency.　 However, the predetermined resonance frequency f0 is the resonance frequency when the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is an appropriate positional relationship, and the resonance frequency of the wireless power transfer system changes depending on whether the relative positional relationship is an appropriate positional relationship, as described below.

[0038] 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 current that fluctuates with the frequency of the high-frequency current flowing through the power transmitter coil 22 flows through the power receiver coil 102.　 The high-frequency current flowing through the power receiver coil 102 is supplied to the rectifier circuit 200 via the power receiver side 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 side main switch 301H and the low-potential side main switch 301L are turned on, the output current of the rectifier circuit 200 is supplied to the high-voltage power storage battery 300 and the driving inverter 310.

[0039] 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 power is supplied from the low-voltage power storage battery 302 to the power receiver side controller 231, the power receiver side controller 231 becomes operable.

[0040] The power receiver device 100 and the power transmitter device 20 have a configuration for communication between the power receiver device 100 and the power transmitter device 20.　 More specifically, the power receiver side coil unit 101 constituting the power receiver device 100 includes a power receiver side communication antenna 170.　 The power receiver side control unit 230 includes a transmitter 240 (also referred to as "TX").

[0041] The power transmitter side coil unit 21 constituting the power transmitter device 20 includes the power transmitter side communication antenna 40.　 The power transmitter side control unit 70 includes a receiver 80 (also referred to as "RX").　 The power receiver side communication antenna 170 and the power transmitter side communication antenna 40 are communication antennas for performing short-range wireless communication.　 The short-range wireless communication is communication with a communication distance of less than 10 meters (for example, a maximum of about 3 meters).　 The short-range wireless communication has a shorter communication distance than wide-area wireless communication.

[0042] As the short-range wireless communication, various near field communication methods can be used, and for example, communication conforming to any communication standard established by IEEE, ISO, IEC, or the like is used.　 Specifically, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), radio frequency identification (RFID), or dedicated short range communication (DSRC) is used as the short-range wireless communication.

[0043] The transmitter 240 is connected to the power receiver side controller 231.　 The power receiver side communication antenna 170 is connected to the transmitter 240.　 The power receiver side controller 231 controls the transmitter 240 to supply a power supply request signal COMM to the power receiver side communication antenna 170.　 The power supply request signal COMM is a signal that requests the power transmitter coil 22 near the vehicle 11 to transmit power to the power receiver coil 102.　 For example, when the state of charge (SOC) of the high-voltage power storage battery 300 is 70% or less, the power receiver side controller 231 controls the transmitter 240 to supply the power supply request signal COMM to the power receiver side communication antenna 170.

[0044] The power receiver side control unit 230 controls the transmitter 240 to supply information including the power supply request signal COMM, ID information of the vehicle 11, a requested power Weq, which is the requested value of power supply to the vehicle 11, and a traveling speed signal indicating a traveling speed Vsp of the vehicle 11, to the power receiver side communication antenna 170, in one frame.　 The traveling speed signal can be acquired based on the output of a vehicle speed sensor mounted on the vehicle 11, for example.　 This control causes the transmitter 240 to apply a high-frequency voltage to the power receiver side communication antenna 170.　 Therefore, a high-frequency current flows through the power receiver side communication antenna 170. and a magnetic field for information communication is generated in the power receiver side communication antenna 170.　 The power receiver side control unit 230 acquires the ID information and the traveling speed Vsp of the vehicle 11 from, for example, a vehicle ECU that controls the vehicle 11.

[0045] In the case where the power receiver side coil unit 101 of the vehicle 11 is close to the power transmitter side coil unit 21 on the ground side, when the generated magnetic field interlinks with the power transmitter side communication antenna 40, a high-frequency current flows in the power transmitter side communication antenna 40.　 This high-frequency current is input to the receiver 80.　 The receiver 80 recognizes the presence or absence of a power supply request and the ID information based on the input signal from the power transmitter side communication antenna 40.　 The receiver 80 acquires the requested power Weq and the traveling speed Vsp of the vehicle 11 having the recognized ID information based on the signal from the power transmitter side communication antenna 40.　 The information recognized by the receiver 80, the requested power Weq, and the traveling speed Vsp are input to the power transmitter side controller 71.

[0046] In the present embodiment, the power receiver side controller 231 controls the transmitter 240 so that the frequency of the high-frequency voltage applied to the power receiver side communication antenna 170 becomes a second specified frequency that is equal to or higher than 10 kHz and equal to or lower than 100 GHz.　 In the present embodiment, the second specified frequency is a frequency that is shifted from the first specified frequency, and specifically, is a frequency that is higher than the first specified frequency (specifically, 13.56 MHz).

[0047] The power transmitter side controller 71 determines whether to energize the power transmitter coil 22 based on an input signal from the receiver 80.　 In detail, when it is determined that there is a power supply request based on an input signal from the receiver 80, the power transmitter side 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.　 Therefore, power is transmitted in a wireless manner from the power transmitter coil 22 to the power receiver coil 102.

[0048] The transmitter 240 and the peripheral configuration thereof will be described with reference to FIG. 4.

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

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

[0051] Next, the receiver 80 and the peripheral configuration thereof will be described with reference to FIG. 5.

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

[0053] The detector circuit 82 detects the high-frequency signal input from the power transmitter side amplifier 81 to calculate an intensity value Intd that is the amplitude or effective value of the input power supply request signal COMM.　 The calculated intensity value Intd is input to the determination circuit 83.

[0054] The determination circuit 83 determines whether there is a power supply request to the power transmitter coil 22 based on the input intensity value Intd.　 In detail, when it is determined that the intensity value Intd exceeds a determination threshold Ijde, the determination circuit 83 determines that there is a power supply request.　 On the other hand, when it is determined that the intensity value Intd falls below (does not exceed) 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 side controller 71.

[0055] When it is determined that there is no power supply request based on the input determination result information, the power transmitter side controller 71 stops switching control of the PFC circuit 61 and the inverter 60.　 Therefore, 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, when it is determined that there is a power supply request based on the input determination result information, the power transmitter side 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 (corresponding to actual energization).　 Therefore, a high-frequency current flows through the power transmitter coil 22.　 In this case, power is supplied in a wireless manner from the power transmitter coil 22 to the power receiver coil 102 that faces the power transmitter coil 22 in the vertical direction.

[0057] When it is determined that there is a power supply request, the power transmitter side controller 71 (that is, the power transmitter side control unit 70) performs the following tracking processing prior to the above actual energization.　 The power transmitter side controller 71 calculates the phase difference of the current with respect to the voltage applied to the power transmitter coil 22 while setting the frequency of the voltage applied to the power transmitter coil 22 to multiple frequencies, which are mutually different to each other, within a predetermined frequency range including the above-mentioned predetermined resonance frequency f0 to tentatively energize the power transmitter coil 22.　 At this time, the transmitted power in the tracking processing is set to be smaller than the transmitted power in the actual energization.　 The phase difference value is expressed as an absolute value regardless of whether the value is positive or negative.　 The power transmitter side controller 71 sets a suitable frequency, which is a frequency among the multiple frequencies of the set applied voltage, at which the calculated phase difference falls below a phase difference threshold (the energized state of the power transmitter coil 22 satisfies a predetermined condition), to the frequency of the high-frequency current flowing through the power transmitter coil 22.　 That is, the power transmitter side controller 71 searches for a suitable frequency, which is the frequency of the voltage applied to the power transmitter coil 22 at which the energized state of the power transmitter coil 22 satisfies a predetermined condition, within the predetermined frequency range including the predetermined resonance frequency f0 of the wireless power transfer system.　 The phase difference threshold may be, for example, a value at which the efficiency of power supply from the power transmitter coil 22 to the power receiver coil 102 becomes larger than a predetermined efficiency, and may be set in advance based on tests or simulations.　 Thereafter, the power transmitter side controller 71 executes the actual energization at the set suitable frequency.　 The power transmitter side controller 71 can also set, as a suitable frequency, a frequency among the multiple frequencies of the set applied voltage, at which the power factor in the power transmitter device 20 exceeds a power factor threshold (the energized state of the power transmitter coil 22 satisfies a predetermined condition).　 The power transmitter side controller 71 can measure (calculate) the power to be supplied to the power transmitter coil 22 when transmitting a predetermined power, and set, as a suitable frequency, a frequency among the multiple frequencies of the set the applied voltage, at which the measured power falls below a power threshold (within an appropriate power range), that is, a frequency at which the energized state of the power transmitter coil 22 satisfies a predetermined condition.

[0058] FIG. 6 is a diagram showing a case in which the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is an appropriate positional relationship.　 As shown in FIG. 6(a), for example, it is considered a situation where the power receiver coil 102 of the vehicle 11 receives power in a wireless manner from the power transmitter coil 22 provided in a parking lot.　 As shown in FIG. 6(b), when the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is an appropriate positional relationship, the leakage magnetic field is reduced and the power supply efficiency is increased.　 In the appropriate positional relationship, the power transmitter coil 22 and the power receiver coil 102 are aligned (or substantially aligned) in a plan view. 　When the power transmitter coil 22 and the power receiver coil 102 face to each other (in an appropriate positional relationship) in this manner, the resonance frequency of the wireless power transfer system becomes the predetermined resonance frequency f0, as shown in FIG. 9.　 As the frequency of the current flowing through the power transmitter coil 22 deviates from the predetermined resonance frequency f0 of the wireless power transfer system, the power to be supplied to the power transmitter coil 22 when transmitting the predetermined power becomes larger, and the power supply efficiency decreases.

[0059] FIG. 7 is a diagram showing an example of a case in which the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is not an appropriate positional relationship.　 In this example, the power receiver coil 102 is oblique with respect to the power transmitter coil 22 in a plan view, and the power transmitter coil 22 and the power receiver coil 102 are misaligned.　 In this case, compared to when the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is an appropriate positional relationship, the leakage magnetic field increases and the power supply efficiency decreases.　 In a situation where the leakage magnetic field is increasing, it is not preferable that the driver of the vehicle 11 enter or exit the vehicle 11 or that a third party H approach the vehicle 11.　 When the power transmitter coil 22 and the power receiver coil 102 are misaligned, there is a problem in that metal parts constituting the vehicle 11 are inductively heated by a leakage magnetic field.　 When the power transmitter coil 22 and the power receiver coil 102 are misaligned (not in an appropriate positional relationship) in this manner, the resonance frequency of the wireless power transfer system becomes, for example, a resonance frequency f1 higher than the predetermined resonance frequency f0, as shown in FIG. 9.　 As the frequency of the current flowing through the power transmitter coil 22 deviates from the resonance frequency f1 of the wireless power transfer system, the power to be supplied to the power transmitter coil 22 when transmitting the predetermined power becomes larger, and the power supply efficiency decreases.　 When the power transmitter coil 22 and the power receiver coil 102 are misaligned, the overall power supplied becomes larger than when the power transmitter coil 22 and the power receiver coil 102 face to each other.

[0060] FIG. 8 is a diagram showing another example in which the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is not an appropriate positional relationship.　 In FIG. 8, components of the vehicle 11 other than the power transmitter coil 22 and the power receiver coil 102 are omitted from illustration.　 In this example, the overall shape of the power transmitter coil 22 and the power receiver coil 102 is rectangular.　 Specifically, the power transmitter coil 22 and the power receiver coil 102 each include one central coil and two end coils.　 In this example as well, the power receiver coil 102 is oblique with respect to the power transmitter coil 22 in a plan view, and the power transmitter coil 22 and the power receiver coil 102 are misaligned.　 In this way, when the overall shape of the power transmitter coil 22 and the power receiver coil 102 is rectangular and the power receiver coil 102 is oblique with respect to the power transmitter coil 22 in a plan view, the increase in leakage magnetic field and the decrease in power supply efficiency become significant.　 In this case as well, the resonance frequency of the wireless power transfer system is, for example, a frequency that is equivalent to the resonance frequency f1 shown in FIG. 9. In the examples of FIGS. 7 and 8, when the vehicle 11 is parked and wireless power transfer from the power transmitter coil 22 to the power receiver coil 102 is started, there is a risk that power supply will continue when an increased leakage magnetic field and a decreased power supply efficiency occur.　 In consideration of this, when a suitable frequency is not found, that is, when it is determined that there is no suitable frequency, the power transmitter side control unit 70 stops energizing the power transmitter coil 22.　 Therefore, power supply is stopped when there is no suitable frequency, that is, when an increase in leakage magnetic field or a decrease in power supply efficiency occurs.　 The same problem may occur not only when the vehicle 11 is parked, but also when the vehicle 11 is stopped.　 The vehicle 11 may be stopped when a red light is detected or before an intersection without traffic lights.

[0061] The lower the traveling speed Vsp of the vehicle 11 is, the higher the possibility that the vehicle 11 will be stopped or parked is.　 In other words, when the traveling speed Vsp of the vehicle 11 is lower than a predetermined speed Vsth, there is a higher possibility that the vehicle 11 will be stopped or parked than when the traveling speed Vsp of the vehicle 11 is not lower than the predetermined speed Vsth.　 When the vehicle 11 is parked and power supply is started when the relative positional relationship is not an appropriate positional relationship, there is a risk that power supply will continue when an increase in the leakage magnetic field and a decrease in the power supply efficiency occurs.　 Therefore, the higher the possibility that the vehicle 11 will be stopped or parked is, the more accurately it is desirable to align the power transmitter coil 22 and the power receiver coil 102.　 In consideration of this, as shown in FIG. 9, the power transmitter side controller 71 narrows the above-mentioned predetermined frequency range when the traveling speed Vsp is lower than the predetermined speed Vsth (Vsp < Vsth) than when the traveling speed Vsp is not lower than the predetermined speed Vsth (Vsp ≧ Vsth).　 Therefore, the higher the possibility that the vehicle 11 will be stopped or parked is, the narrower the predetermined frequency range within which a suitable frequency is searched for is.　 That is, in order for power supply to start, the higher the possibility that the vehicle 11 will be stopped or parked, the more accurate the alignment between the power transmitter coil 22 and the power receiver coil 102 needs to be.　 The center of the predetermined frequency range when Vsp ≧ Vsth holds is set in accordance with the tendency of the resonance frequency of the wireless power transfer system to deviate from the predetermined resonance frequency f0 to the resonance frequency f1 when changing from the facing state to the misaligned state.

[0062] FIG. 10 is a flowchart of energization control of the power transmitter coil 22 executed by the power transmitter side control unit 70.

[0063] The power transmitter side amplifier 81 of the receiver 80 amplifies the high-frequency signal received by the power transmitter side communication antenna 40 and inputs the amplified signal to a detector circuit 82 (S10).

[0064] The detector circuit 82 calculates the intensity value Intd of the power supply request signal COMM based on the input signal from the power transmitter side amplifier 81 (S11).　 The detector circuit 82 acquires the ID information of the vehicle 11 based on the input signal from the power transmitter side amplifier 81.

[0065] The determination circuit 83 determines whether the intensity value Intd calculated in step S11 exceeds the determination threshold Ijde (S12).　 In this determination, when it is determined that the intensity value Intd does not exceed the determination threshold Ijde (S12: NO), determination result information that there is no power supply request is input to the power transmitter side controller 71, and this series of processing is temporarily ended (END).　 That is, the power transmitter side controller 71 stops the switching control of the PFC circuit 61 and the inverter 60 to keep the switches of the PFC circuit 61 and the inverter 60 off, and does not perform the energization of the power transmitter coil 22.

[0066] On the other hand, when it is determined in step S12 that the intensity value Intd exceeds the determination threshold Ijde (S12: YES), the power transmitter side controller 71 is input with the determination result information that there is a power supply request.

[0067] Next, the detector circuit 82 acquires the traveling speed Vsp of the vehicle 11 based on the input signal (more specifically, the traveling speed signal) from the power transmitter side amplifier 81 (S13).　 That is, the power transmitter side control unit 70 acquires the traveling speed Vsp by using short-range wireless communication with the vehicle 11.

[0068] Next, the predetermined frequency range is changed based on the traveling speed Vsp (S14).　 Specifically, as shown in FIG. 11, when the traveling speed Vsp is lower than the predetermined speed Vsth, the lower the traveling speed Vsp is, the narrower the predetermined frequency range becomes continuously, that is, the lower the traveling speed Vsp is, the narrower the predetermined frequency range within which a suitable frequency is searched for becomes continuously.　 The predetermined speed Vsth is, for example, a speed equal to or lower than 10 km / h (slow moving speed of the vehicle 11), and specifically, is set to 5 km / h (standard walking speed of a person).　 It can also be said that the predetermined frequency range is narrower when the traveling speed Vsp is lower than the predetermined speed Vsth indicated by the dashed line, compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 That is, it can also be said that the predetermined frequency range within which a suitable frequency is searched for is narrower when the traveling speed Vsp is lower than the predetermined speed Vsth indicated by the dashed line, compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 The position of the predetermined frequency range is set with respect to the frequency so that the predetermined frequency range includes the above-mentioned predetermined resonance frequency f0.

[0069] Next, the power transmitter side controller 71 executes tracking processing (S15).　 Specifically, the power transmitter side controller 71 calculates the phase difference of the current with respect to the voltage applied to the power transmitter coil 22 while setting the frequency of the voltage applied to the power transmitter coil 22 to multiple frequencies, which are mutually different to each other, within the predetermined frequency range set in the processing of S14, in sequence from high frequency to low frequency or from low frequency to high frequency, to tentatively energize the power transmitter coil 22.　 The power transmitter side controller 71 sets a frequency (suitable frequency) among the multiple frequencies of the set applied voltage, at which the calculated phase difference falls below the phase difference threshold, to the frequency of the high-frequency current flowing through the power transmitter coil 22.　 On the other hand, even though a suitable frequency is searched for within the predetermined frequency range, there may be cases where there is no suitable frequency.

[0070] Next, it is determined whether there is a suitable frequency (S16).　 In this determination, when it is determined that there is a suitable frequency is present (S16: YES), the power transmitter coil 22 is energized (S17).　 Specifically, the power transmitter side controller 71 executes actual energization with a larger transmitted power than the energization during the tracking processing (corresponding to tentative energization) at the suitable frequency set in the tracking processing in S15.　 the power transmitter side controller 71 executes the switching control of the PFC circuit 61 and the inverter 60 to energize the power transmitter coil 22.　 Thereafter, this series of processing is temporarily ended (END).

[0071] On the other hand, when it is determined in step S16 that there is no suitable frequency (S16: NO), the energization of the power transmitter coil 22 is stopped (S18).　 Specifically, the power transmitter side controller 71 stops the switching control of the PFC circuit 61 and the inverter 60 to turn off the switches of the PFC circuit 61 and the inverter 60, and stops the energization of the power transmitter coil 22.　 Thereafter, this series of processing is temporarily ended (END).

[0072] The program that causes the power transmitter side control unit 70 to execute the processing shown in the flowchart of FIG. 7 corresponds to a power transmission program.　 The method for causing the power transmitter side control unit 70 to execute the processing shown in the flowchart of FIG. 7 corresponds to a control method for the power transmitter device 20.

[0073] According to the present embodiment described above, the following effects are obtained.

[0074] The power transmitter side control unit 70 searches for a suitable frequency, which is the frequency of the voltage applied to the power transmitter coil 22 at which the energized state of the power transmitter coil 22 satisfies a predetermined condition, within a predetermined frequency range including the predetermined resonance frequency f0 of the wireless power transfer system having the power transmitter coil 22 and the power receiver coil 102, and when it is determined that there is a suitable frequency, sets the suitable frequency to the frequency of the current flowing through the power transmitter coil 22.　 Therefore, the power supplied to the power transmitter coil 22 when transmitting a predetermined power is reduced, and power supply efficiency can be improved.　 In response to this, the power transmitter side control unit 70 stops energizing the power transmitter coil 22 when it is determined that there is no suitable frequency.　 Therefore, it is possible to stop power supply when there is no suitable frequency, that is, when an increase in the leakage magnetic field and a decrease in the power supply efficiency occur.

[0075] Based on the traveling speed signal received by the power transmitter side communication antenna 40, the power transmitter side control unit 70 narrows the predetermined frequency range when the traveling speed Vsp is lower than the predetermined speed Vsth than when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 Therefore, when the traveling speed Vsp of the vehicle 11 is lower than the predetermined speed Vsth and there is a higher possibility of parking or stopping than when the traveling speed Vsp is not lower than the predetermined speed Vsth, power supply is more likely to be stopped when an increase in the leakage magnetic field or a decrease in the power supply efficiency occurs.　 Therefore, it is possible to prevent power supply from continuing when the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 deviates from an appropriate positional relationship.

[0076] When the traveling speed Vsp is lower than the predetermined speed Vsth, the power transmitter side control unit 70 narrows the predetermined frequency range as the traveling speed Vsp decreases.　 According to this configuration, in a situation where there is a high possibility that the vehicle 11 will be parked or stopped, it is possible to accurately narrow the predetermined frequency range with which a search for a suitable frequency is performed.

[0077] The predetermined speed Vsth is set to a speed equal to or lower than 10 km / h.　 With this configuration, when the traveling speed Vsp becomes 10 km / h or less, that is, when the vehicle 11 moves slowly, the predetermined frequency range can be narrowed.

[0078] When it is determined that there is a power supply request, the power transmitter side control unit 70 calculates the phase difference of the current with respect to the voltage applied to the power transmitter coil 22 while setting the frequency of the voltage applied to the power transmitter coil 22 to multiple frequencies, which are mutually different to each other, to tentatively energize the power transmitter coil 22, sets the frequency among the multiple frequencies of the set applied voltage, at which the calculated phase difference falls below the phase difference threshold, as a suitable frequency, when it is determined that there is no suitable frequency, stops energizing the power transmitter coil 22, when it is determined that there is a suitable frequency, sets the suitable frequency to the frequency of the current flowing through the power transmitter coil 22, and executes actual energization with a transmitted power larger than the transmitted power of the tentative energization.　 According to this configuration, it is possible to search for a suitable frequency during tentative energization with a transmitted power smaller than the transmitted power of the actual energization.　 As a result, power consumption when searching for a suitable frequency can be reduced compared to a configuration in which a suitable frequency is searched for when actual energization is executed.

[0079] The above-described embodiment can be changed and carried out as follows.　 The same parts as those in the above embodiment are denoted by the same reference numerals and the description thereof will be repeated.

[0080] As shown in FIG. 12, when the traveling speed Vsp is lower than the predetermined speed Vsth, the predetermined frequency range may be narrowed in a stepwise manner as the traveling speed Vsp becomes lower.　 That is, when the traveling speed Vsp is lower than the predetermined speed Vsth, the predetermined frequency range within which a suitable frequency is searched for may be narrowed in a stepwise manner.　 The above configuration can also provide the same effects as the above embodiment.　 It can also be said that the predetermined frequency range is narrower when the traveling speed Vsp is lower than the predetermined speed Vsth indicated by the dashed line, compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.

[0081] As shown in FIG. 13, the lower the traveling speed Vsp is, the narrower the predetermined frequency range may be continuously, that is, the lower the traveling speed Vsp, the narrower the predetermined frequency range within which a suitable frequency is searched for may be continuously.　 With the above configuration, when the traveling speed Vsp is lower than the predetermined speed Vsth, it is possible to achieve the same effects as those of the above embodiment.　 It can also be said that the predetermined frequency range is narrower when the traveling speed Vsp is lower than any given predetermined speed Vsth indicated by the dashed line, compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 That is, it can also be said that the predetermined frequency range within which a suitable frequency is searched for is narrower when the traveling speed Vsp is lower than any given predetermined speed Vsth indicated by the dashed line, compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.

[0082] In FIG. 13, when the traveling speed Vsp is lower than the predetermined speed Vsth, the predetermined frequency range may be narrowed in a stepwise manner as the traveling speed Vsp becomes lower.　 That is, when the traveling speed Vsp is lower than the predetermined speed Vsth, the predetermined frequency range within which a suitable frequency is searched for may be narrowed in a stepwise manner.　 With the above configuration, when the traveling speed Vsp is lower than the predetermined speed Vsth, it is possible to achieve the same effects as those of the above embodiment.

[0083] As shown in FIG. 14, when the traveling speed Vsp is lower than the predetermined speed Vsth, the predetermined frequency range may be uniformly narrowed with the predetermined speed Vsth as a boundary, compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 That is, it can be said that when the traveling speed Vsp is lower than the predetermined speed Vsth, the predetermined frequency range within which a suitable frequency is searched for is uniformly narrowed compared to when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 The above configuration can also provide the same effects as the above embodiment.

[0084] The wireless power transfer system having the power transmitter coil 22 and the power receiver coil 102 can employ the wireless power transfer method shown in FIGS. 15 to 18.

[0085] FIG. 15 is a diagram showing an SS-type wireless power transfer method.　 In the SS type, a resonant capacitor 31 of the power transmitter side resonant circuit 30 is connected in series to the power transmitter coil 22.　 In the SS type, the resonant capacitor 141 of the power receiver side resonant circuit 140 is connected in series to the power receiver coil 102.

[0086] FIG. 16 is a diagram showing a wireless power transfer method of the SP method.　 In the SP system, the resonant capacitor 32 of the power transmitter side resonant circuit 30 is connected in series to the power transmitter coil 22.　 In the SP system, the resonant capacitor 142 of the power receiver side resonant circuit 140 is connected in parallel to the power receiver coil 102.

[0087] FIG. 17 is a diagram showing a PS-type wireless power transfer method.　 In the PS type, the resonant capacitor 33 of the power transmitter side resonant circuit 30 is connected in series to the power transmitter coil 22.　 In the PS type, the resonant capacitor 143 of the power receiver side resonant circuit 140 is connected in series to the power receiver coil 102.

[0088] FIG. 18 is a diagram showing a PP-type wireless power transfer method.　 In the PP type, the resonant capacitor 34 of the power transmitter side resonant circuit 30 is connected in parallel to the power transmitter coil 22.　 In the PP type, the resonant capacitor 144 of the power receiver side resonant circuit 140 is connected in parallel to the power receiver coil 102.

[0089] During the actual energization after the tracking processing, the power transmitter side control unit 70 may search for a suitable frequency within the predetermined frequency range set in the processing of S14 in FIG. 10.　 When it is determined that there is a suitable frequency, the suitable frequency may be set to the frequency of the current flowing through the power transmitter coil 22, and when it is determined that there is no suitable frequency, the energization of the power transmitter coil 22 may be stopped.　 Even with this configuration, it is possible to achieve the same effects as the above embodiment.　 The power transmitter side control unit 70 may omit the tracking processing by tentative energization and search for a suitable frequency within the predetermined frequency range set in the processing of S14 in FIG. 10 when executing the tracking processing by actual energization.　 When it is determined that there is a suitable frequency, the suitable frequency may be set to the frequency of the current flowing through the power transmitter coil 22, and when it is determined that there is no suitable frequency, the energization of the power transmitter coil 22 may be stopped.

[0090] The wireless power transfer system 10 may have a second function of supplying power in a wireless manner from a vehicle-side device to a device on the ground side, in addition to a first function of supplying power in a wireless manner from a device on the ground side to a vehicle-side device.　 In this case, the vehicle-side power receiver device 100 has a power transmitter function in addition to a power receiver function.　 The power transmitter device 20 on the ground side has a power receiver function in addition to a power transmitter function.　 The second function will be described below with reference to FIG. 3.

[0091] The power receiver device 100 has a power transmitter function of supplying power from the power receiver coil 102 to the power transmitter coil 22 of the power transmitter device 20 in a wireless manner.　 Specifically, the power receiver side controller 231 applies a high frequency AC voltage to the power receiver coil 102 by controlling the switching of the rectifier circuit 200 that functions as a DC / AC convertor circuit.　 Therefore, a high-frequency current flows through the power receiver coil 102, and a magnetic field for power transmission is generated in the power receiver coil 102.

[0092] When the magnetic field generated in the power receiver coil 102 interlinks with the power transmitter coil 22, a high-frequency current that fluctuates with the frequency of the high-frequency current flowing through the power receiver coil 102 flows through the power transmitter coil 22.　 The high-frequency current flowing through the power transmitter coil 22 is supplied to the AC power source 15 via the power transmitter side resonant circuit 30, the filter circuit 52, the inverter 60, and the PFC circuit 61.　 In this case, the power transmitter side controller 71 controls the switching of the inverter 60 and the PFC circuit 61.

[0093] In the wireless power transfer system 10 having the second function, for example, the power transmitter side control unit 70 (power transmitter device 20) may include a transmitter that supplies a power supply request signal (corresponding to a power transmitter function execution request signal) to the power transmitter side communication antenna 40.　 The power receiver device 100 may include a receiver that receives the power supply request signal received by the power receiver side communication antenna 170 and inputs the signal to the power receiver side controller 231.

[0094] The power receiver side control unit 230 may control the energization of the power receiver coil 102 as follows.　 That is, the power receiver side control unit 230 searches for a power receiver side suitable frequency, which is the frequency of the voltage applied to the power receiver coil 102 at which the energized state of the power receiver coil 102 satisfies a power receiver side predetermined condition, within a predetermined frequency range including the above-mentioned predetermined resonance frequency f0, and when it is determined that there is a power receiver side suitable frequency, sets the power receiver side suitable frequency to the frequency of the current flowing through the power receiver coil 102.　 Specifically, the power receiver side control unit 230 calculates the phase difference of the current with respect to the voltage applied to the power receiver coil 102 while setting the frequency of the voltage applied to the power receiver coil 102 to multiple frequencies, which are mutually different to each other, to tentatively energize the power receiver coil 102, and sets the frequency among the multiple frequencies of the set applied voltage, at which the calculated phase difference falls below the phase difference threshold, as a power receiver side suitable frequency.　 When it is determined that there is a power receiver side suitable frequency, the power receiver side suitable frequency is set to the frequency of the current flowing through the power receiver coil 102, and actual energization is executed with a transmitted power larger than the transmitted power of the tentative energization.　 The power receiver side control unit 230 stops energization to the power receiver coil 102 when it is determined that there is no power receiver side suitable frequency.　 Therefore, it is possible to stop the execution of the power transmitter function when the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 is not an appropriate positional relationship, that is, when an increase in the leakage magnetic field or a decrease in the power supply efficiency occurs.

[0095] The power receiver side control unit 230 narrows the predetermined frequency range based on the traveling speed signal when the traveling speed Vsp is lower than the predetermined speed Vsth than when the traveling speed Vsp is not lower than the predetermined speed Vsth.　 Therefore, when the traveling speed Vsp of the vehicle 11 is lower than the predetermined speed Vsth and there is a higher possibility of parking or stopping than when the traveling speed Vsp is not lower than the predetermined speed Vsth, the execution of the power transmitter function is more likely to be stopped when an increase in the leakage magnetic field or a decrease in the power supply efficiency occurs.　 Therefore, it is possible to prevent power supply from continuing when the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 deviates from an appropriate positional relationship.　 When it is determined in the determination of S16 in FIG. 11 that a current Is is not smaller than a threshold Ith (S16: NO), in addition to the processing of stopping energizing the power transmitter coil 22 in S18, the power transmitter side control unit 70 may transmit a signal to the vehicle ECU to notify that the energization of the power transmitter coil 22 has been stopped.　 Therefore, the vehicle ECU can easily display (voice guidance) on the instrument panel of the vehicle 11 or the image display unit of a navigation device to notify the driver of the vehicle 11 that energization of the power transmitter coil 22 has been stopped, display a message instructing the driver to correct the relative positional relationship between the power transmitter coil 22 and the power receiver coil 102 to an appropriate positional relationship, and display a message recommending that the driver use an automatic parking function.

[0096] The traveling speed signal may be acquired from a change in the position information of the vehicle 11 calculated based on a GPS signal, or may be acquired based on the reflected waves of electromagnetic waves emitted by a Doppler radar.　 The traveling speed signal is not limited to one that represents the vehicle speed as a numerical value, but may represent the vehicle speed by the intensity of a signal, or by the position of a bit that is 1 in data consisting of multiple bits. The power receiver side communication antenna and the power transmitter side communication antenna are not limited to communication coils, and various antennas may be used.　 For example, the communication antenna is a dipole antenna or a monopole antenna. The method of wireless power transfer by the power transmitter antenna and the power receiver antenna is not limited to the magnetic field resonance method, and may be an electric field coupling method.　 In this 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. In the wireless power transfer system 10. the power transmitter device 20 may perform wide-area wireless communication with the power receiver device 100.　 The wide-area wireless communication has a longer communication distance than short-range wireless communication.　 Examples of wide-area wireless communication that can be used include 3GPP (registered trademark), 4G, LTE, 5G, and WiMAX (registered trademark) defined by IEEE.　 The power transmitter side control unit 70 and the power receiver side control unit 230 may transmit and receive information using wide-area wireless communication.

[0097] The power transmitter side controller 71 (power transmitter side control unit 70) and the method described in the present disclosure may be implemented by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions (instructions) embodied by a computer program.　 Alternatively, the power transmitter side controller 71 and the method described in the present disclosure may be implemented by a dedicated computer provided by forming a processor with one or more dedicated hardware logic circuits.　 Alternatively, the power transmitter side controller 71 and the method described in the present disclosure may be implemented by one or more dedicated computers including a combination of a processor and a memory programmed to execute one or multiple functions and a processor including one or more hardware logic circuits.　 The computer program may be stored in a computer-readable non-transitory tangible storage medium, as an instruction executed by a computer.

[0098] The present disclosure is described based on the examples, and it is understood that this disclosure is not limited to the examples or the structure.　 The present disclosure includes various modification examples and modifications within the equivalent scope.　 Although various combinations and configurations 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.

[0099] Characteristic configurations extracted from each of the above-described embodiments and each of modification examples will be described below. (Configuration 1) A power transmitter device is to be applied to a wireless power transfer system (10) including the power transmitter device (20) and a power receiver device (100).　 The power transmitter device (20) includes: a power transmitter antenna (22); a power transmitter side control unit (70) configured to supply power in a wireless manner from the power transmitter antenna to a power receiver antenna (102) of the power receiver device mounted on a vehicle (11) and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna; and a power transmitter side communication antenna (40).　 The power receiver device includes a power receiver side communication antenna (170) for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna.　 The power transmitter side control unit is configured to energize the power transmitter antenna when determining that there is power supply request based on the power supply request signal received by the power transmitter side communication antenna, search for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna, set a frequency of a current flowing through the power transmitter antenna to the suitable frequency when determining that there is the suitable frequency, stop energizing of the power transmitter antenna when determining that there is no suitable frequency, and based on the traveling speed signal received by the power transmitter side communication antenna, narrow the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed. (Configuration 2) The power transmitter device according to configuration 1, in which, when the traveling speed is lower than the predetermined speed, the power transmitter side control unit is configured to narrow the predetermined frequency range as the traveling speed becomes lower. (Configuration 3) The power transmitter device according to configuration 1 or 2, in which the predetermined speed is set to a speed equal to or lower than 10 km / h. (Configuration 4) The power transmitter device according to any one of configurations 1 to 3, in which the power transmitter side control unit is configured to, when determining that there is power supply request, calculate a phase difference of a current with respect to the voltage applied to the power transmitter antenna, while setting the frequency of the voltage applied to the power transmitter antenna to a plurality of frequencies, which are mutually different from each other, to execute tentative energization of the power transmitter antenna, and set, as the suitable frequency, a frequency at which the calculated phase difference falls below a phase difference threshold, among the set frequencies of the applied voltage.　 The power transmitter side control unit is configured to, when determining that there is no suitable frequency, stop energizing of the power transmitter antenna.　 The power transmitter side control unit is configured to, when determining that there is the suitable frequency, set the frequency of the current flowing through the power transmitter antenna to the suitable frequency and execute actual energization of the power transmitter antenna with a transmitted power larger than a transmitted power of the tentative energization. (Configuration 5) The power transmitter device according to any one of configurations 1 to 3, in which the power transmitter side control unit is configured to, when determining that there is power supply request, calculate a power to be supplied to the power transmitter antenna when transmitting a predetermined power, while setting the frequency of the voltage applied to the power transmitter antenna to a plurality of frequencies, which are mutually different from each other, to execute tentative energization of the power transmitter antenna, and set, as the suitable frequency, a frequency, at which the calculated power is within an appropriate power range, among the plurality of set frequencies of the applied voltage.　 The power transmitter side control unit is configured to, when determining that there is no suitable frequency, stop energizing of the power transmitter antenna.　 The power transmitter side control unit is configured to, when determining that there is the suitable frequency, set the frequency of the current flowing through the power transmitter antenna to the suitable frequency and execute actual energization of the power transmitter antenna with a transmitted power larger than a transmitted power of the tentative energization. (Configuration 6) The power transmitter device according to any one of configurations 1 to 5, in which the power transmitter antenna is a first power transmitter antenna configured to supply power to the vehicle while parked.　 The power transmitter device further includes: a second power transmitter antenna configured to supply power to the vehicle while traveling. (Configuration 7) The wireless power transfer system (10) according to any one of configurations 1 to 6, includes: the power transmitter device; and the power receiver device.　 The power receiver device has a power transmitter function to supply power to the power transmitter antenna of the power transmitter device in a wireless manner from the power receiver antenna.　 The power receiver device includes a power receiver side control unit (230) configured to control energization of the power receiver antenna to supply power to the power transmitter antenna in a wireless manner.　 The power transmitter side control unit is configured to supply a power transmitter function execution request signal indicating request for the power receiver device to execute the power transmitter function to the power transmitter side communication antenna.　 The power receiver side control unit is configured to, when determining that there is the request to execute the power transmitter function based on the received power transmitter function execution request signal received by the power receiver side communication antenna, energize the power receiver antenna and search for a power receiver side suitable frequency, which is a frequency of a voltage applied to the power receiver antenna and at which an energized state of the power receiver antenna satisfies a power receiver side predetermined condition, within the predetermined frequency range including the predetermined resonance frequency.　 The power receiver side control unit is configured to, when determining that there is the power receiver side suitable frequency, set a frequency of a current flowing through the power receiver antenna to the power receiver side suitable frequency.　 The power receiver side control unit is configured to, when determining that there is no power receiver side suitable frequency, stop energizing the power receiver antenna.　 The power receiver side control unit is configured to, based on the traveling speed signal, narrow the predetermined frequency range when the traveling speed is lower than the predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

Claims

1. A power transmitter device to be applied to a wireless power transfer system (10) including the power transmitter device (20) and a power receiver device (100), 　　　　　　 the power transmitter device (20) comprising: 　　　　　　 a power transmitter antenna (22); 　　　　　　 a power transmitter side control unit (70) configured to supply power in a wireless manner from the power transmitter antenna to a power receiver antenna (102) of the power receiver device mounted on a vehicle (11) and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna; and 　　　　　　 a power transmitter side communication antenna (40), wherein 　　　　　　 the power receiver device includes a power receiver side communication antenna (170) for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna, 　　　　　　 the power transmitter side control unit is configured to 　　　　　　　　　　　　　 energize the power transmitter antenna when determining that there is the power supply request based on the power supply request signal received by the power transmitter side communication antenna, 　　　　　　　　　　　　　 search for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna, 　　　　　　　　　　　　　 set a frequency of a current flowing through the power transmitter antenna to the suitable frequency when determining that there is the suitable frequency, 　　　　　　　　　　　　　 stop energizing of the power transmitter antenna when determining that there is no suitable frequency, and 　　　　　　　　　　　　　 based on the traveling speed signal received by the power transmitter side communication antenna, narrow the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

2. The power transmitter device according to claim 1, wherein 　　　　　　 when the traveling speed is lower than the predetermined speed, the power transmitter side control unit is configured to narrow the predetermined frequency range as the traveling speed becomes lower.

3. The power transmitter device according to claim 1 or 2, wherein 　　　　　　 the predetermined speed is set to a speed equal to or lower than 10 km / h.

4. The power transmitter device according to claim 1 or 2, wherein 　　　　　　 the power transmitter side control unit is configured to, when determining that there is the power supply request, 　　　　　　　　　　　　　 calculate a phase difference of a current with respect to the voltage applied to the power transmitter antenna, while setting the frequency of the voltage applied to the power transmitter antenna to a plurality of frequencies, which are mutually different from each other, to execute tentative energization of the power transmitter antenna, and 　　　　　　　　　　　　　 set, as the suitable frequency, a frequency at which the calculated phase difference falls below a phase difference threshold, among the set frequencies of the applied voltage, 　　　　　　 the power transmitter side control unit is configured to, when determining that there is no suitable frequency, 　　　　　　　　　　　　　 stop energizing of the power transmitter antenna, and 　　　　　　 the power transmitter side control unit is configured to, when determining that there is the suitable frequency, 　　　　　　　　　　　　　 set the frequency of the current flowing through the power transmitter antenna to the suitable frequency and 　　　　　　　　　　　　　 execute actual energization of the power transmitter antenna with a transmitted power larger than a transmitted power of the tentative energization.

5. The power transmitter device according to claim 1 or 2, wherein 　　　　　　 the power transmitter side control unit is configured to, when determining that there is the power supply request, 　　　　　　　　　　　　　 calculate a power to be supplied to the power transmitter antenna when transmitting a predetermined power, while setting the frequency of the voltage applied to the power transmitter antenna to a plurality of frequencies, which are mutually different from each other, to execute tentative energization of the power transmitter antenna, and 　　　　　　　　　　　　　 set, as the suitable frequency, a frequency, at which the calculated power is within an appropriate power range, among the plurality of set frequencies of the applied voltage, 　　　　　　 the power transmitter side control unit is configured to, when determining that there is no suitable frequency, 　　　　　　　　　　　　　 stop energizing of the power transmitter antenna, and 　　　　　　 the power transmitter side control unit is configured to, when determining that there is the suitable frequency, 　　　　　　　　　　　　　 set the frequency of the current flowing through the power transmitter antenna to the suitable frequency and 　　　　　　　　　　　　　 execute actual energization of the power transmitter antenna with a transmitted power larger than a transmitted power of the tentative energization.

6. The power transmitter device according to claim 1 or 2, wherein 　　　　　　 the power transmitter antenna is a first power transmitter antenna configured to supply power to the vehicle while parked, and 　　　　　　 the power transmitter device further comprising: 　　　　　　 a second power transmitter antenna configured to supply power to the vehicle while traveling.

7. The wireless power transfer system (10) according to claim 1 or 2, comprising: 　　　　　　 the power transmitter device; and 　　　　　　 the power receiver device, wherein 　　　　　　 the power receiver device has a power transmitter function to supply power to the power transmitter antenna of the power transmitter device in a wireless manner from the power receiver antenna, 　　　　　　 the power receiver device includes a power receiver side control unit (230) configured to control energization of the power receiver antenna to supply power to the power transmitter antenna in a wireless manner, 　　　　　　 the power transmitter side control unit is configured to supply a power transmitter function execution request signal indicating request for the power receiver device to execute the power transmitter function to the power transmitter side communication antenna, 　　　　　　 the power receiver side control unit is configured to, when determining that there is the request to execute the power transmitter function based on the received power transmitter function execution request signal received by the power receiver side communication antenna, 　　　　　　　　　　　　　 energize the power receiver antenna and 　　　　　　　　　　　　　 search for a power receiver side suitable frequency, which is a frequency of a voltage applied to the power receiver antenna and at which an energized state of the power receiver antenna satisfies a power receiver side predetermined condition, within the predetermined frequency range including the predetermined resonance frequency, 　　　　　　 the power receiver side control unit is configured to, when determining that there is the power receiver side suitable frequency, 　　　　　　　　　　　　　 set a frequency of a current flowing through the power receiver antenna to the power receiver side suitable frequency, 　　　　　　 the power receiver side control unit is configured to, when determining that there is no power receiver side suitable frequency, 　　　　　　　　　　　　　 stop energizing the power receiver antenna, and 　　　　　　 the power receiver side control unit is configured to, based on the traveling speed signal, narrow the predetermined frequency range when the traveling speed is lower than the predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

8. A power transmission program for controlling a power transmitter device to be applied to a wireless power transfer system (10), the wireless power transfer system (10) including a power transmitter device (20) and a power receiver device (100), the power transmitter device (20) including a power transmitter antenna (22), a power transmitter side control unit (70) configured to supply power in a wireless manner from the power transmitter antenna to the power receiver antenna of the power receiver device mounted on a vehicle and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna, and a power transmitter side communication antenna (40), the power receiver device including a power receiver side communication antenna (170) for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna, 　　　　　　 the power transmission program configured to cause the power transmitter side control unit to execute processing comprising: 　　　　　　　　　　　　　 energizing the power transmitter antenna when determining that there is the power supply request based on the power supply request signal received by the power transmitter side communication antenna; 　　　　　　　　　　　　　 searching for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna; 　　　　　　　　　　　　　 setting, when determining that there is the suitable frequency, a frequency of a current flowing through the power transmitter antenna to the suitable frequency; 　　　　　　　　　　　　　 stopping, when determining that there is no suitable frequency, energizing of the power transmitter antenna; and 　　　　　　　　　　　　　 narrowing, based on the traveling speed signal received by the power transmitter side communication antenna, the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

9. A control method for a power transmitter device to be applied to a wireless power transfer system (10), the wireless power transfer system (10) including a power transmitter device (20) and a power receiver device (100), the power transmitter device (20) including a power transmitter antenna (22), a power transmitter side control unit (70) configured to supply power in a wireless manner from the power transmitter antenna to a power receiver antenna (102) of the power receiver device mounted on a vehicle and control energization of the power transmitter antenna to supply power in a wireless manner to the power receiver antenna, and a power transmitter side communication antenna (40), the power receiver device including a power receiver side communication antenna (170) for wireless communication with the power transmitter side communication antenna and configured to supply a power supply request signal indicating power supply request to the power transmitter antenna and a traveling speed signal indicating traveling speed of the vehicle to the power receiver side communication antenna, 　　　　　　 the method comprising: 　　　　　　 causing the power transmitter side control unit to execute processing of 　　　　　　　　　　　　　 energizing the power transmitter antenna, when determining that there is the power supply request based on the power supply request signal received by the power transmitter side communication antenna, 　　　　　　　　　　　　　 searching for a suitable frequency, which is a frequency of a voltage applied to the power transmitter antenna and at which an energized state of the power transmitter antenna satisfies a predetermined condition, within a predetermined frequency range including a predetermined resonance frequency of the wireless power transfer system including the power transmitter antenna and the power receiver antenna, 　　　　　　　　　　　　　 setting, when determining that there is the suitable frequency, a frequency of a current flowing through the power transmitter antenna to the suitable frequency, 　　　　　　　　　　　　　 stopping, when determining that there is no suitable frequency, energizing of the power transmitter antenna, and 　　　　　　　　　　　　　 narrowing, based on the traveling speed signal received by the power transmitter side communication antenna, the predetermined frequency range when the traveling speed is lower than a predetermined speed, compared to when the traveling speed is not lower than the predetermined speed.

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