WO2022144994A1

WO2022144994A1 - Foreign matter detection device, power transmission device, power reception device, and power transmission system

Info

Publication number: WO2022144994A1
Application number: PCT/JP2020/049176
Authority: WO
Inventors: 和樹近藤; 明後谷
Original assignee: Tdk株式会社
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2022-07-07

Abstract

In the present invention, a detection unit (180) assesses whether foreign matter is present on the basis of the result of comparison of the output value of a sensor and a threshold value. The detection unit (180) executes a threshold value correction process for correcting the threshold value on the basis of the output value and a parameter value, which is the value of a correction parameter used in correction of the threshold value.

Description

Foreign matter detection device, power transmission device, power receiving device, and power transmission system

This disclosure relates to a foreign matter detection device, a power transmission device, a power receiving device, and a power transmission system.

Wireless power transmission technology that transmits power wirelessly is attracting attention. Since wireless power transmission technology can transmit power wirelessly from a power transmission device to a power receiving device, it is expected to be applied to various products such as transportation equipment such as trains and electric vehicles, home appliances, wireless communication equipment, and toys. In wireless power transmission technology, a transmission coil and a power receiving coil coupled by magnetic flux are used for power transmission.

By the way, if foreign matter such as metal pieces is present in the vicinity of the power transmission coil and the power reception coil, various problems may occur. For example, such foreign matter may adversely affect the power transmission from the power transmission coil to the power reception coil, or may generate heat due to eddy currents. Therefore, there is a demand for a foreign matter detecting device that appropriately detects foreign matter existing in the vicinity of the power transmission coil and the power receiving coil.

For example, Patent Document 1 compares the voltage generated in a plurality of sensor coils with a reference voltage table, and determines whether or not a foreign substance exists in the vicinity of a search coil in which the plurality of sensor coils are arranged in a plane. The non-contact power transmission device to be discriminated is described. The non-contact power transmission device described in Patent Document 1 stores the voltage generated in a plurality of sensor coils as a reference voltage table when no foreign matter is present in the vicinity of the search coil.

Further, Patent Document 2 describes a foreign substance detection method for determining the presence or absence of a foreign substance by comparing the measured quality factor value with the critical value determined based on the reference quality factor value. In the foreign substance detection method described in Patent Document 2, a weighted value increased by a reference quality factor value is applied to determine a critical value.

International Publication No. 2014-156655 Special Table 2019-526220 Gazette

By the way, when the environment surrounding the foreign matter detection device changes, the sensor value detected by the sensor of the foreign matter detection device may change. Here, if the threshold value does not change even though the sensor value changes, it is difficult to accurately detect the foreign matter. Therefore, when the environment surrounding the foreign matter detection device changes, it is desirable to change the threshold value to be compared with the sensor value according to the environment. However, neither the invention described in Patent Document 1 nor the invention described in Patent Document 2 appropriately changes the threshold value in accordance with changes in the environment, so that it is difficult to detect foreign substances with high accuracy. Is considered to be. Therefore, in the detection of foreign matter in wireless power transmission, a technique for detecting foreign matter with high accuracy is desired.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to detect foreign matter with high accuracy in the detection of foreign matter in wireless power transmission.

In order to solve the above problems, the foreign matter detection device according to one embodiment of the present disclosure is
With the sensor
A detection unit for determining the presence or absence of a foreign substance based on the comparison result between the output value of the sensor and the threshold value is provided.
The detection unit executes a threshold value correction process for correcting the threshold value based on the output value and the parameter value which is the value of the correction parameter used for the correction of the threshold value.

According to the power transmission device having the above configuration, foreign matter can be detected with high accuracy in the foreign matter detection of wireless power transmission.

Schematic configuration diagram of the power transmission system according to the first embodiment Layout of the foreign matter detection device according to the first embodiment Configuration diagram of the foreign matter detection device according to the first embodiment Top view of the detection coil unit according to the first embodiment The figure which shows the equivalent circuit of the resonance circuit provided in the detection coil unit which concerns on Embodiment 1. Configuration diagram of the power transmission device according to the first embodiment Explanatory diagram of the correspondence between the output value, the threshold value, and the number of measurements Explanatory drawing of the reference area The figure which shows the 1st parameter table The figure which shows the 2nd parameter table The figure which shows the 3rd parameter table A flowchart showing a foreign matter detection process executed by the foreign matter detection device according to the first embodiment. A flowchart showing the first parameter change process shown in FIG. A flowchart showing the change process for each installation height shown in FIG. A flowchart showing the second parameter change process shown in FIG. A flowchart showing the third parameter change process shown in FIG. A flowchart showing the output value acquisition process shown in FIG. A flowchart showing a threshold value change process executed by the foreign matter detection device according to the second embodiment. The figure which shows the 4th parameter table Layout of the foreign matter detection device according to the fifth embodiment

Hereinafter, the power transmission system according to the embodiment of the technique according to the present disclosure will be described with reference to the drawings. In the following embodiments, the same components are designated by the same reference numerals. In addition, the size ratio and shape of the components shown in each figure are not necessarily the same as those at the time of implementation.

(Embodiment 1)
The power transmission system according to the present embodiment can be used for charging secondary batteries of various devices such as EVs (Electric Vehicles), mobile devices such as smartphones, and industrial devices. Hereinafter, a case where the power transmission system executes charging of the storage battery of the EV will be illustrated.

FIG. 1 is a diagram showing a schematic configuration of a power transmission system 1000 used for charging a storage battery 500 provided in an electric vehicle 700. The electric vehicle 700 runs on a motor driven by electric power charged in a storage battery 500 such as a lithium ion battery or a lead storage battery as a power source. The electric vehicle 700 is an example of a moving body.

As shown in FIG. 1, the power transmission system 1000 is a system that wirelessly transmits power from a power transmission device 200 to a power reception device 300 by magnetic coupling. The power transmission system 1000 includes a power transmission device 200 that wirelessly transmits the power of an AC or DC commercial power source 400 to the electric vehicle 700, and a power receiving device 300 that receives the power transmitted by the power transmission device 200 and charges the storage battery 500. .. In the following description, the commercial power supply 400 is an AC power supply.

The power transmission device 200 is a device that wirelessly transmits power to the power receiving device 300 by magnetic coupling. The power transmission device 200 includes a foreign matter detection device 100 for detecting foreign matter, a power transmission coil unit 210 for transmitting AC power to the electric vehicle 700, and a power supply device 220 for supplying AC power to the power transmission coil unit 210. As shown in FIG. 2, the foreign matter detecting device 100 is arranged on the power transmission coil unit 210. In FIG. 2, the vertically upward axis is the Z axis, the axis orthogonal to the Z axis is the X axis, and the axis orthogonal to the Z axis and the X axis is the Y axis. A detailed description of the foreign matter detecting device 100 will be described later.

As shown in FIG. 2, the power transmission coil unit 210 is supplied with AC power from the power supply device 220 and passes through the power transmission coil 211 that induces an alternating magnetic flux Φ and the magnetic force generated by the power transmission coil 211 to cause a loss of magnetic force. A magnetic plate 212 for suppressing is provided. The power transmission coil 211 is configured by winding a conducting wire spirally on a magnetic plate 212. Capacitors provided at both ends of the power transmission coil 211 and the power transmission coil 211 form a resonance circuit, and an alternating magnetic field Φ is induced by an alternating current flowing with the application of an alternating voltage.

The magnetic plate 212 has a plate shape with a hole in the central portion and is composed of a magnetic material. The magnetic plate 212 is, for example, a plate-shaped member made of ferrite, which is a composite oxide of iron oxide and a metal. The magnetic plate 212 may be composed of an aggregate of a plurality of magnetic material pieces, and the plurality of magnetic material pieces are arranged in a frame shape and formed so as to have an opening in the central portion. You may.

The power supply device 220 includes a power factor improving circuit for improving the power factor of commercial AC power supplied by the commercial power supply 400, and an inverter circuit for generating AC power supplied to the power transmission coil 211. The power factor improving circuit rectifies and boosts the AC power generated by the commercial power supply 400 and converts it into DC power having a predetermined voltage value. The inverter circuit converts the DC power generated by the power factor improving circuit by the power conversion into AC power having a predetermined frequency. The power transmission device 200 is fixed to the floor surface of the parking lot, for example.

The power receiving device 300 is a device that receives power from the power transmitting device 200 wirelessly by magnetic coupling. The power receiving device 300 includes a power receiving coil unit 310 that receives AC power transmitted by the power transmitting device 200, and a rectifying circuit 320 that converts AC power supplied from the power receiving coil unit 310 into DC power and supplies it to the storage battery 500. Be prepared.

As shown in FIG. 2, the power receiving coil unit 310 passes the power receiving coil 311 that induces an electromotive force in response to a change in the alternating magnetic flux Φ induced by the power transmitting coil 211 and the magnetic force generated by the power receiving coil 311 to obtain the magnetic force. A magnetic plate 312 that suppresses loss is provided. The power receiving coil 311 and the capacitors provided at both ends of the power receiving coil 311 form a resonance circuit. The power receiving coil 311 faces the power transmission coil 211 in a state where the electric vehicle 700 is stopped at a preset position. When the transmission coil 211 induces an alternating magnetic flux Φ by receiving the power from the power supply device 220, the alternating magnetic flux Φ is interlinked with the power receiving coil 311 to induce an induced electromotive force in the power receiving coil 311.

The magnetic plate 312 is a plate-shaped member having a hole in the central portion, and is composed of a magnetic material. The magnetic plate 312 is, for example, a plate-shaped member made of ferrite, which is a composite oxide of iron oxide and a metal. The magnetic plate 312 may be composed of an aggregate of a plurality of magnetic material pieces, and the plurality of magnetic material pieces are arranged in a frame shape and formed so as to have an opening in the central portion. You may.

The rectifier circuit 320 rectifies the electromotive force induced in the power receiving coil 311 to generate DC power. The DC power generated by the rectifier circuit 320 is supplied to the storage battery 500. Even if the power receiving device 300 includes a charging circuit between the rectifier circuit 320 and the storage battery 500, the DC power supplied from the rectifier circuit 320 is converted into an appropriate DC power for charging the storage battery 500. good. The power receiving device 300 is fixed to, for example, the chassis of the electric vehicle 700.

The communication device 600 is a communication device mounted on the electric vehicle 700. The communication device 600 communicates with each of the power transmission device 200 and the power receiving device 300. Further, the communication device 600 communicates with various servers connected to the communication network via the communication network. The communication device 600 transmits the moving body state information and the height information, which will be described later, to the power transmission device 200. The communication device 600 is, for example, an in-vehicle computer that controls the entire operation of the electric vehicle 700.

The terminal device 800 is a device that receives a notification from the foreign matter detecting device 100 that there is a foreign matter. The terminal device 800 is, for example, a smartphone owned by a user of the electric vehicle 700. Upon receiving the notification from the foreign matter detecting device 100 that the foreign matter is present, the terminal device 800 notifies the user of the presence of the foreign matter by displaying a screen, outputting voice, or the like.

The foreign matter detecting device 100 detects foreign matter existing in the detection target area. The detection target area is a region for detecting foreign matter, and is a region where foreign matter can be detected. The detection target region is a region near the power transmission coil unit 210 and the power reception coil unit 310, and is a region including a region between the power transmission coil unit 210 and the power reception coil unit 310. Foreign matter is an object or living body that is not necessary for power transmission.

If foreign matter is placed in the detection target area during power transmission, it may adversely affect power transmission or generate heat. Therefore, the foreign matter detecting device 100 detects the foreign matter existing in the detection target area and notifies the user that the foreign matter has been detected. Upon receiving this notification, the user can remove the foreign matter. Various foreign substances such as metal pieces, humans, and animals are assumed. As shown in FIG. 2, the foreign matter detection device 100 is a device in which the detection unit 180 detects foreign matter based on a signal output by the detection coil unit 110 to which a voltage pulse is supplied from the pulse generation unit 140.

Hereinafter, the configuration of the foreign matter detecting device 100 will be described with reference to FIG. As shown in FIG. 3, the foreign matter detection device 100 includes a detection coil unit 110, a pulse generation unit 140, a storage unit 150, a first communication unit 160, a second communication unit 170, a detection unit 180, and a pulse. Control unit 181, switch control unit 182, output value acquisition unit 183, notification unit 184, power transmission control unit 185, moving body state acquisition unit 186, height information acquisition unit 187, and operation state acquisition unit 188. And a temperature information acquisition unit 189.

The detection coil unit 110 is a unit that detects foreign matter. As shown in FIG. 4, the detection coil unit 110 is formed in a flat plate shape and is arranged on the power transmission coil unit 210 so as to overlap the power transmission coil 211 in a plan view. The detection coil unit 110 includes a detection coil substrate 130 made of a permeable magnetic material typified by a resin.

At least one sensor coil 120 is mounted on the detection coil board 130. In the present embodiment, the detection coil substrate 130 includes the sensor coil 120A, the sensor coil 120B, the sensor coil 120C, the sensor coil 120D, the sensor coil 120E, the sensor coil 120F, the sensor coil 120G, the sensor coil 120H, the sensor coil 120I, and the sensor. Twelve sensor coils 120 of the coil 120J, the sensor coil 120K, and the sensor coil 120L are mounted. Each sensor coil 120, the pulse generation unit 140, and the detection unit 180 are connected by wiring (not shown). The sensor coil 120 is an example of a sensor.

A resonance circuit included in the detection coil unit 110, which is an equivalent circuit of the resonance circuit including the sensor coil 120, will be described with reference to FIG. As shown in FIG. 5, this resonant circuit includes a sensor coil 120, a capacitor 131, a switch 132, and a switch 133. The sensor coil 120 has a conductor pattern that is wound once or multiple times around an axis parallel to the Z axis.

One terminal of the sensor coil 120 is connected to one terminal of the switch 132, and is connected to one end of the pulse generating unit 140 via wiring. The other terminal of the sensor coil 120 is connected to one terminal of the capacitor 131 and one terminal of the switch 133. The other terminal of the switch 133 is connected to the other end of the pulse generating unit 140 via wiring. The other terminal of the capacitor 131 is connected to the other terminal of the switch 132.

The switch 132 and the switch 133 are controlled to an on state or an off state according to the control from the switch control unit 182 via a control line (not shown). The on state is a conducting state, and the off state is a non-conducting state. The switch 132 has a function of switching a state between the sensor coil 120 and the capacitor 131. When the switch 132 is turned on, the sensor coil 120 and the capacitor 131 form a resonant circuit. The switch 133 has a function of switching the state between the resonance circuit and the pulse generating unit 140.

That is, when both the switch 132 and the switch 133 are turned on, the sensor coil 120 and the capacitor 131 form a resonant circuit, and a pulsed voltage is applied to the resonant circuit from the pulse generating unit 140 via wiring. Will be done. The voltage between both ends of the resonance circuit, that is, the voltage between both ends of the sensor coil 120 is guided to the output value acquisition unit 183 via wiring. When the switch 132 is turned off, the sensor coil 120 and the capacitor 131 do not form a resonance circuit. Further, when the switch 133 is turned off, the resonance circuit is electrically disconnected from the pulse generation unit 140 and the output value acquisition unit 183.

FIG. 5 shows that the foreign matter 10 is present in the vicinity of the resonance circuit. It is assumed that the switch 132 is closed and the sensor coil 120 and the capacitor 131 form a resonance circuit, the switch 133 is closed, and a pulse voltage is applied from the pulse generating unit 140. The voltage signal representing the voltage between both ends of the resonance circuit is a vibration signal whose peak value gradually attenuates with the passage of time after the pulse voltage drops, that is, after the current to the sensor coil 120 is cut off. ..

If the foreign matter 10 is present in the vicinity of the sensor coil 120, the inductance of the sensor coil 120 changes. Therefore, when the foreign matter 10 is present, the frequency of the vibration signal changes and the degree of attenuation of the vibration signal changes as compared with the case where the foreign matter 10 does not exist. The detection unit 180 determines the presence or absence of the foreign matter 10 by detecting a change in the frequency of the vibration signal, a change in the degree of attenuation of the vibration signal, and the like.

The pulse generation unit 140 generates a pulse-shaped voltage for detecting foreign matter. The pulse generation unit 140 applies the generated voltage to one sensor coil 120 selected by the switch control unit 182.

The storage unit 150 stores programs and data used by the foreign matter detection device 100 to execute various processes. For example, the storage unit 150 stores the first parameter table, the second parameter table, and the third parameter table. Further, the storage unit 150 stores data generated or acquired by the foreign matter detecting device 100 by executing various processes. For example, the storage unit 150 stores the output value acquired by the output value acquisition unit 183, the threshold value for discriminating the output value, and the initial value of the threshold value.

In the present embodiment, an independent threshold value and an initial value of the threshold value are provided for each of the 12 sensor coils 120. The initial value of the threshold value is set based on the results of experiments, simulations, and the like. The storage unit 150 includes, for example, a non-volatile semiconductor memory such as a flash memory, an EPROM (ErasableProgrammableROM), and an EEPROM (ElectricallyErasableProgrammableROM).

The first communication unit 160 communicates with the terminal device 800. The first communication unit 160 conforms to well-known wireless communication standards such as Wi-Fi (registered trademark), Bluetooth (registered trademark), LTE (LongTermEvolution), 4G (4thGeneration), and 5G (5thGeneration). And communicates with the terminal device 800. The first communication unit 160 includes a communication interface conforming to the above-mentioned wireless communication standard.

The second communication unit 170 communicates with the power transmission device 200. The second communication unit 170 conforms to a well-known wired communication standard such as USB (Universal Serial Bus, registered trademark), Thunderbolt (registered trademark), or a well-known wireless communication standard such as Wi-Fi and Bluetooth. Communicate with the power transmission device 200. The second communication unit 170 includes a communication interface conforming to the above-mentioned wired communication standard or the above-mentioned wireless communication standard.

The detection unit 180, the pulse control unit 181, the switch control unit 182, the output value acquisition unit 183, the notification unit 184, the transmission control unit 185, the moving object state acquisition unit 186, and the height information acquisition unit 187. The operating state acquisition unit 188 and the temperature information acquisition unit 189 are, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an RTC (Real Time Clock), and an A / D ( It is realized by a computer equipped with an Analog / Digital) converter or the like by executing an operation program stored in a ROM or a storage unit 150.

The detection unit 180 detects the foreign matter 10 existing in the foreign matter detection region based on the signal output from each sensor coil 120. Specifically, first, the detection unit 180 controls the switch control unit 182 to select any one of the 12 sensor coils 120. Then, the detection unit 180 controls the pulse control unit 181 to apply a voltage on the pulse to the selected sensor coil 120. The detection unit 180 compares the output value based on the signal output by the selected sensor coil 120 with the threshold value, and determines whether or not the foreign matter 10 is present in the detection target region. The detection unit 180 controls the notification unit 184 to notify the terminal device 800 of the detection result indicating the presence or absence of the foreign matter 10. The detection unit 180 repeats such a process while switching the sensor coil 120 to be selected.

The pulse control unit 181 generates a single pulse-like voltage in the pulse generation unit 140 according to the control by the detection unit 180. This pulsed voltage is applied to the resonant circuit formed in the selected sensor coil 120 via wiring. Further, the voltage between both ends of the resonance circuit is guided to the output value acquisition unit 183 via the wiring.

The switch control unit 182 turns on the switch 132 and the switch 133 of the sensor coil 120 selected by the detection unit 180 according to the control by the detection unit 180, and turns off the switch 132 and the switch 133 of the sensor coil 120 not selected. To.

The output value acquisition unit 183 acquires the output value of the selected sensor coil 120 from the vibration signal representing the voltage between both ends of the resonance circuit according to the control by the detection unit 180. The value of the output value acquired by the output value acquisition unit 183 can be appropriately adjusted. For example, the output value can be the frequency of the vibration signal, the convergence time of the vibration signal, the magnitude of the amplitude of the vibration signal, or the like. The convergence time of the vibration signal is, for example, the time from when the pulsed voltage is applied until the amplitude of the vibration signal falls below a predetermined amplitude. The magnitude of the amplitude of the vibration signal is, for example, the magnitude of the amplitude of the vibration signal when a predetermined time has elapsed since the pulsed voltage was applied.

The notification unit 184 transmits the detection result by the detection unit 180 to the terminal device 800 according to the control by the detection unit 180. For example, when the detection unit 180 determines that the foreign matter 10 is present, the notification unit 184 transmits information indicating that the foreign matter 10 has been detected via the first communication unit 160. On the other hand, the terminal device 800 notifies the user that a foreign substance has been detected by displaying a screen, outputting a voice, or the like.

The power transmission control unit 185 controls the power transmission to the power receiving coil unit 310 by the power transmission coil unit 210 according to the control by the detection unit 180. For example, when the detection unit 180 determines that the foreign matter 10 is present, the power transmission control unit 185 transmits control information instructing the power supply device 220 to stop power transmission via the second communication unit 170.

The moving body state acquisition unit 186 acquires moving body state information indicating the state of the moving body including the position of the moving body and the moving state of the moving body. In this embodiment, the moving body is an electric vehicle 700. The position of the moving body is represented by, for example, the relative position of the moving body with respect to the installation position of the power transmission device 200. The moving state of the moving body is expressed by, for example, whether or not the moving body is moving, how fast the moving body is moving, and the like. The mobile body state acquisition unit 186 acquires mobile body state information from the power transmission device 200 via the second communication unit 170.

The height information acquisition unit 187 acquires height information indicating the installation height of the power receiving coil 311. The installation height of the power receiving coil 311 is the height of the position where the power receiving coil 311 is installed, and is expressed by, for example, the distance from the floor surface or the road surface to the installation position of the power receiving coil 311. The height information acquisition unit 187 acquires height information from the power transmission device 200 via the second communication unit 170.

The operating state acquisition unit 188 acquires operating state information indicating the operating state of the power supply device 220. The operating state of the power supply device 220 is expressed by, for example, whether or not power transmission is in progress, whether or not the power to be transmitted is constant, and how much the power to be transmitted is increased or decreased. The operating state acquisition unit 188 acquires operating state information from the power transmission device 200 via the second communication unit 170.

The temperature information acquisition unit 189 acquires temperature information indicating the temperature of a specific part of the power transmission device 200. It is possible to appropriately adjust which part the specific part is to be. For example, the specific portion may be a part or a vicinity part of the power transmission coil unit 210, or a part or a vicinity part of the foreign matter detection device 100. The temperature information acquisition unit 189 acquires temperature information from the power transmission device 200 via the second communication unit 170.

Next, the configuration of the power transmission device 200 will be described with reference to FIG. As shown in FIG. 6, the power transmission device 200 includes a foreign matter detection device 100, a power transmission coil unit 210, a power supply device 220, a storage unit 230, a first communication unit 240, a second communication unit 250, and a temperature. The sensor 260, the control unit 270, the power transmission control unit 271, the operation state acquisition unit 272, the moving body state acquisition unit 273, the height information acquisition unit 274, the control information reception unit 275, and the information transfer unit 276. , A temperature information acquisition unit 277 is provided.

The storage unit 230 stores programs and data used by the power transmission device 200 to execute various processes. Further, the storage unit 230 stores data generated or acquired by the power transmission device 200 by executing various processes. For example, the storage unit 230 has the operation state information acquired by the operation state acquisition unit 272, the moving body state information acquired by the moving body state acquisition unit 273, the height information acquired by the height information acquisition unit 274, and the temperature. The temperature information acquired by the information acquisition unit 277 is stored. The storage unit 230 includes, for example, a non-volatile semiconductor memory such as a flash memory, EPROM, or EEPROM.

The first communication unit 240 communicates with the communication device 600. The first communication unit 240 communicates with the terminal device 800 according to well-known wireless communication standards such as Wi-Fi, Bluetooth, LTE, 4G, and 5G. The first communication unit 240 includes a communication interface conforming to the above-mentioned wireless communication standard.

The second communication unit 250 communicates with the foreign matter detection device 100. The second communication unit 250 communicates with the foreign matter detection device 100 according to, for example, a well-known wired communication standard such as USB or Thunderbolt, or a well-known wireless communication standard such as Wi-Fi or Bluetooth. The second communication unit 250 includes a communication interface compliant with a wired communication standard such as USB or Thunderbolt, or a wireless communication standard such as Wi-Fi or Bluetooth.

The temperature sensor 260 measures the temperature of a specific part of the power transmission device 200. The temperature sensor 260 is attached to the power transmission coil unit 210, for example, and measures the temperature of a part or a vicinity of the power transmission coil unit 210.

Control unit 270, power transmission control unit 271, operating state acquisition unit 272, moving body state acquisition unit 273, height information acquisition unit 274, control information reception unit 275, information transfer unit 276, and temperature information acquisition. The unit 277 is realized by, for example, a computer equipped with a CPU, ROM, RAM, RTC, A / D conversion device, etc., executing an operation program stored in the ROM or the storage unit 230.

The control unit 270 controls the operation of the entire power transmission device 200. For example, the control unit 270 controls the power supply device 220 to control the power transmission to the power receiving device 300. Further, the control unit 270 communicates with the communication device 600 via the first communication unit 240. Further, the control unit 270 communicates with the foreign matter detecting device 100 via the second communication unit 250.

The power transmission control unit 271 controls power transmission to the power receiving device 300 according to the control by the control unit 270. That is, the power transmission control unit 271 supplies AC power to the power transmission coil unit 210 and generates magnetic flux in the power transmission coil 211 according to the control by the power transmission unit 270.

The operating state acquisition unit 272 acquires the operating state information indicating the operating state of the power supply device 220. For example, the operating state acquisition unit 272 acquires the operating state information from the power supply device 220.

The moving body state acquisition unit 273 acquires moving body state information indicating the state of the moving body including the position of the moving body and the moving state of the moving body. For example, the moving body state acquisition unit 273 acquires operating state information from the communication device 600 mounted on the electric vehicle 700. The communication device 600 can specify the position of the electric vehicle 700, for example, based on an image captured by an in-vehicle camera mounted on the electric vehicle 700. Further, the communication device 600 can specify the moving state of the electric vehicle 700 based on the vehicle speed information output by the speedometer mounted on the electric vehicle 700.

The height information acquisition unit 274 acquires height information indicating the installation height of the power receiving coil 311. For example, the height information acquisition unit 274 acquires height information from the communication device 600 mounted on the electric vehicle 700. The mounting position of the power receiving device 300 in the electric vehicle 700 is basically the bottom surface corresponding to the lowest portion of the vehicle body of the electric vehicle 700. Further, the minimum ground clearance, which is the distance from the lowest portion of the vehicle body of the electric vehicle 700 to the ground, is basically determined for each type of the electric vehicle 700 classified by the vehicle name. Here, it is assumed that the communication device 600 is connected to a server that stores the minimum ground clearance information indicating the minimum ground clearance for each type of the electric vehicle 700 via a communication network. In this case, the communication device 600 specifies the minimum ground clearance according to the type of the electric vehicle 700 with reference to the minimum ground clearance information stored in this server, and the installation height of the power receiving coil 311 is specified from the specified minimum ground clearance. Can be identified.

The control information receiving unit 275 receives control information related to power transmission control from the foreign matter detecting device 100. For example, the control information receiving unit 275 receives the control information instructing the stop of power transmission from the foreign matter detecting device 100 via the second communication unit 250.

Transfers various information stored in the information transfer unit 276 and the storage unit 230 to the foreign matter detection device 100. For example, the information transfer unit 276 receives a transmission request for various information from the foreign matter detection device 100 via the second communication unit 250, acquires the information requested by the transmission request from the storage unit 230, and receives the information requested by the transmission request from the storage unit 230, and the second communication unit 250. Is transmitted to the foreign matter detecting device 100 via the above. The information required by the transmission request is, for example, operating state information, moving body state information, height information, temperature information, and the like.

The temperature information acquisition unit 277 acquires temperature information indicating the temperature of a specific part of the power transmission device 200. For example, the temperature information acquisition unit 277 acquires temperature information indicating the measured temperature of a part or a vicinity portion of the power transmission coil unit 210 from the temperature sensor 260.

Next, the operation of each part included in the foreign matter detecting device 100 will be described in detail.

First, the detection unit 180 determines the presence or absence of the foreign matter 10 based on the comparison result between the output value of the sensor coil 120 and the threshold value. In the present embodiment, the output value output by the sensor coil 120 when the foreign matter 10 is present is higher than the output value output by the sensor coil 120 when the foreign matter 10 is not present, and the threshold value is the upper limit of the output value. Imagine a case. That is, in the present embodiment, the detection unit 180 determines that there is a foreign matter 10 when the output value of the sensor coil 120 exceeds the threshold value, and there is no foreign matter 10 when the output value of the sensor coil 120 is equal to or less than the threshold value. To determine.

Here, it is considered that the output value of the sensor coil 120 is affected by the environment surrounding the foreign matter detection device 100, for example, the state of the moving body on which the power receiving device 300 is mounted, the power transmission state of the power transmission device 200, and the like. That is, it is considered that the output value of the sensor coil 120 changes in response to these changes in the environment. Therefore, it is preferable to appropriately change the threshold value in accordance with these changes in the environment. Therefore, in the present embodiment, it is considered that these changes in the environment appear as changes in the output value of the sensor coil 120, and the threshold value is changed based on the output value of the sensor coil 120.

Specifically, the detection unit 180 executes a threshold value correction process for correcting the threshold value based on the output value and the parameter value which is the value of the correction parameter. The correction parameter is a parameter used for correcting the threshold value. How to set the correction parameters can be adjusted as appropriate. In the present embodiment, the correction parameter is the number of output values used when obtaining the moving average of the output values. That is, in the threshold value correction process, the detection unit 180 corrects the threshold value by using the value of the moving average of the output values corresponding to the number indicated by the parameter value, which was acquired most recently.

For example, the detection unit 180 adopts a value obtained by adding a predetermined offset value to the moving average value of the number of output values indicated by the parameter value as a new threshold value. For example, if the output value is 2 (V) and the offset value is 1 (V) 10 times in a row, the moving average value is 2 (V) and the new threshold is 3 (V). .. According to such a threshold value correction process, when the output value changes due to a change in the environment, erroneous detection based on the change in the output value not caused by the presence of the foreign matter 10 is reduced.

For example, it is assumed that the output value of the sensor coil 120 increases while the electric vehicle 700 approaches the power transmission device 200 even if the foreign matter 10 does not exist. In this case, if the threshold value is unchanged, the output value increased by the approach of the electric vehicle 700 exceeds the threshold value, and there is a high possibility that it is erroneously determined that the foreign matter 10 is present. However, when the threshold value is changed by the threshold value correction process, the threshold value is increased in accordance with the increase in the output value, so that it is unlikely that the foreign matter 10 is erroneously determined. On the other hand, even if the threshold value is changed by the threshold value correction process, if the foreign matter 10 invades the detection target of the foreign matter detection device 100 and the output value rises sharply, the output value exceeds the threshold value, so that the foreign matter 10 is present. It is judged appropriately.

Further, the ease with which the output value of the sensor coil 120 changes varies depending on the environment surrounding the foreign matter detection device 100. For example, in the absence of the foreign matter 10, when the electric vehicle 700 is moving near the power receiving device 300, the output value of the sensor coil 120 tends to change rapidly. On the other hand, in the absence of the foreign matter 10, when the electric vehicle 700 is stopped far away from the power receiving device 300, the output value of the sensor coil 120 hardly changes. Therefore, the detection unit 180 changes the ease of change of the threshold value, that is, the speed at which the threshold value follows the output value, according to the ease of change of the output value.

Hereinafter, with reference to FIG. 7, the speed at which the threshold value follows the output value will be described. FIG. 7 is a graph showing the correspondence between the number of measurements, the output value, and the threshold value set by the detection unit 180. In FIG. 7, the output value is indicated by a black circle, the first threshold value is indicated by a white circle, and the second threshold value is indicated by a white triangle. The first threshold value is a threshold value when the parameter value, which is the number of output values when the moving average is obtained, is continuously 10. The second threshold is the threshold when the parameter value changes from 10 to 3. The stable period is a period during which the output value of the sensor coil 120 is stable. The unstable period is a period in which the output value of the sensor coil 120 is not stable. FIG. 7 shows how the stable period is switched to the unstable period when the number of measurements exceeds 15.

As shown in FIG. 7, the output value stabilizes at a voltage value of about 2 (V) during the stable period, and the output value sharply rises from 2 (V) when the unstable period is entered. Here, since the parameter value is 10 during the stable period, a value of about 2 (V) is calculated as the value of the moving average of the latest 10 output values. Therefore, during the stable period, a threshold value of about 3 (V), which is obtained by adding an offset value of 1 (V) to a value of about 2 (V), is continuously calculated.

Here, if the parameter value is 10 even after shifting to the unstable period, the moving average value of the 10 output values gradually increases from a value of about 2 (V), so that the threshold value is 3 (V). It gradually rises from the value of the degree. That is, if the parameter value is 10 even after the transition to the unstable period, the change in the threshold value cannot keep up with the change in the output value, and there is a high possibility that the output value exceeds the threshold value. Therefore, if the parameter value is 10 even after the transition to the unstable period, there is a high possibility that it is erroneously determined that the foreign matter 10 is present even though the foreign matter 10 is not present.

On the other hand, when the parameter value becomes 3 after shifting to the unstable period, the value of the moving average of the three output values rises rapidly from the value of about 2 (V), so the threshold value is 3 (V). ) It rises rapidly from the value of about. That is, when the parameter value becomes 3 after shifting to the unstable period, the change in the threshold value follows the change in the output value, so that the possibility that the output value exceeds the threshold value is low. Therefore, when the parameter value becomes 3 after shifting to the unstable period, it is unlikely that the foreign matter 10 is determined to be present even though the foreign matter 10 is not present, and the possibility of erroneous detection is low.

As described above, in the unstable period, it is preferable to set the parameter value to a small value so that the threshold value quickly follows the output value. If the parameter value is set to a small value, the probability that the output value increased due to the presence of the foreign matter 10 does not exceed the threshold value increases. That is, if the parameter value is too small, there is a high possibility that it is determined that there is no foreign matter even though the foreign matter 10 is present, and there is a high possibility that the detection will be missed. Therefore, in the stable period, it is preferable to set the parameter value to a large value so that the threshold value gently follows the output value. As described above, it is preferable to adjust the followability of the threshold value with respect to the output value according to the ease of change of the output value of the sensor coil 120. According to such a configuration, erroneous detection and detection omission are suppressed, and highly accurate detection can be expected.

In the present embodiment, the detection unit 180 changes the parameter value according to the state of the moving body indicated by the moving body state information acquired by the moving body state acquisition unit 186. That is, the detection unit 180 changes the parameter value according to the easiness of fluctuation of the output value according to the position of the moving body and the moving state of the moving body. For example, the detection unit 180 changes the parameter value when the state of the moving body indicated by the moving body state information changes to the first state. The first state is a state in which the position of the moving body is within the reference region and the moving state of the moving body is the moving state.

The reference area is an area close to the power transmission device 200. For example, as shown in FIG. 8, the reference region is a region in which the distance from P0, which is the center point of the power transmission device 200, is L1 or less in a plan view. Further, when P1 which is the center point of the moving body of the electric vehicle 700 is within the reference region, it is considered that the position of the moving body is within the reference region. The period in which the state of the moving body is the first state is an unstable period in which the output value of the sensor coil 120 changes abruptly. Therefore, when the state of the moving body changes from the non-first state to the first state, the detection unit 180 changes the parameter value to a smaller value.

Here, when the state of the moving body indicated by the moving body state information is the first state, the detection unit 180 changes the parameter value according to the moving speed of the moving body. Here, it is considered that the faster the moving speed of the moving body, the faster the output value of the sensor coil 120 changes. Therefore, the detection unit 180 changes the parameter value to a smaller value as the moving speed of the moving body is faster.

Further, when the state of the moving body indicated by the moving body state information is the first state, the detection unit 180 responds to the installation height of the power receiving coil 311 indicated by the height information acquired by the height information acquisition unit 187. Change the parameter value. Here, it is considered that the lower the installation height of the power receiving coil 311 is, the faster the output value of the sensor coil 120 changes. Therefore, the detection unit 180 changes the parameter value to a smaller value as the installation height of the power receiving coil 311 is lower.

The correspondence between the state of the moving body and the parameter value and the correspondence between the installation height of the power receiving coil 311 and the parameter value can be adjusted as appropriate. In the present embodiment, as shown in FIG. 9, the correspondence between the state of the moving body, the installation height of the power receiving coil 311 and the parameter value is defined by the first parameter table stored in the storage unit 150.

According to the first parameter table, when the position of the moving body is outside the reference region, the parameter value is 10 regardless of the moving state of the moving body and the installation height of the power receiving coil 311. When the position of the moving body is within the reference region, the moving body is moving at high speed, and the installation height of the power receiving coil 311 is low, the parameter value is 2. When the position of the moving body is within the reference region, the moving body is moving at high speed, and the installation height of the power receiving coil 311 is a medium height, the parameter value is 3. When the position of the moving body is within the reference region, the moving body is moving at high speed, and the installation height of the power receiving coil 311 is high, the parameter value is 4.

When the position of the moving body is within the reference region and the moving body is moving at a medium speed, the parameter value is 5 regardless of the installation height of the power receiving coil 311. Further, when the position of the moving body is within the reference region and the moving body is moving at a low speed, the parameter value is 7 regardless of the installation height of the power receiving coil 311. Further, when the position of the moving body is within the reference region and the moving body is stopped, the parameter value is 10 regardless of the installation height of the power receiving coil 311. As described above, when the position of the moving body is within the reference region, the detection unit 180 changes the parameter value to a smaller value as the moving speed of the moving body is faster and the installation height of the power receiving coil 311 is lower. do.

Further, the detection unit 180 changes the parameter value according to the operation state of the power supply device 220 indicated by the operation state information acquired by the operation state acquisition unit 188. That is, the detection unit 180 changes the parameter value according to the easiness of fluctuation of the output value according to the operating state of the power supply device 220. For example, the detection unit 180 changes the parameter value according to the amount of change in the magnitude of the transmitted power per unit time. The transmitted power is AC power supplied from the power supply device 220 to the power transmission coil 211. Here, it is considered that the larger the amount of change in the magnitude of the transmitted power per unit time, the faster the output value of the sensor coil 120 changes. Therefore, the detection unit 180 changes the parameter value to a smaller value as the amount of change in the magnitude of the transmitted power per unit time increases.

The correspondence between the operating state of the power supply device 220 and the parameter value can be adjusted as appropriate. In the present embodiment, as shown in FIG. 10, the correspondence between the operating state of the power supply device 220 and the parameter value is defined by the second parameter table stored in the storage unit 150.

According to the second parameter table, the parameter value is 10 when the power supply device 220 has stopped power transmission or when the power supply device 220 is transmitting power with a constant power. Further, when the power supply device 220 transmits power while significantly increasing the transmitted power, or when the power supply device 220 transmits power while significantly reducing the transmitted power, the parameter value is 3. The parameter value is 5 when the power supply device 220 is transmitting power while increasing the transmitted power to a moderate level, or when the power supply device 220 is transmitting power while decreasing the transmitted power to a moderate level. The parameter value is 7 when the power supply device 220 is transmitting power while slightly increasing the transmitted power, or when the power supply device 220 is transmitting power while slightly decreasing the transmitted power. In this way, the detection unit 180 changes the parameter value to a smaller value as the change in the transmitted power transmitted by the power supply device 220 increases.

Further, the detection unit 180 changes the parameter value according to the temperature of the specific portion indicated by the temperature information acquired by the temperature information acquisition unit 189. That is, the detection unit 180 changes the parameter value according to the easiness of fluctuation of the output value according to the temperature of the specific portion of the power transmission device 200. The correspondence between the temperature of the specific portion of the power transmission device 200 and the parameter value can be appropriately adjusted. In the present embodiment, as shown in FIG. 11, the correspondence between the temperature of the specific portion of the power transmission device 200 and the parameter value is defined by the third parameter table stored in the storage unit 150.

According to the third parameter table, when the temperature of a specific part is high, the parameter value is added by 3. That is, when the temperature of a specific part is high, the parameter value according to the moving state of the moving body and the installation height of the power receiving coil 311 or the parameter value according to the operating state of the power supply device 220 (hereinafter, "other elements"). A value obtained by adding 3 to the parameter value corresponding to the parameter value is set as the parameter value. Further, when the temperature of the specific part is a medium temperature, the parameter value is not changed. That is, when the temperature of a specific part is a medium temperature, parameter values corresponding to other factors are set.

Also, if the temperature of a specific part is low, the parameter value is added by 1. That is, when the temperature of the specific portion is low, the value obtained by adding 1 to the parameter value corresponding to the other element is set as the parameter value. If the parameter value exceeds the upper limit value, the parameter value is set to the upper limit value. If the parameter value exceeds the lower limit, the parameter value is set to the lower limit. In the present embodiment, the upper limit value of the parameter is 10, and the lower limit value of the parameter is 2.

Next, with reference to FIG. 12, the foreign matter detection process executed by the foreign matter detection device 100 will be described. The foreign matter detection process is started, for example, when the foreign matter detection device 100 receives a notification from the power supply device 220 to start power transmission.

First, the detection unit 180 included in the foreign matter detection device 100 executes the initial setting (step S101). This initial setting is the initial setting related to the foreign matter detection process. In the initial setting, for example, the switch 132 and the switch 133 included in the detection coil unit 110 are set to the off state. Further, in the initial setting, an initial value of a predetermined threshold value is set as the threshold value. When the detection unit 180 completes the process of step S101, the detection unit 180 executes the first parameter change process (step S102). The first parameter change process will be described in detail with reference to the flowchart shown in FIG.

First, the detection unit 180 acquires the moving body state information (step S201). For example, the detection unit 180 instructs the moving body state acquisition unit 186 to acquire the moving body state information. On the other hand, the moving body state acquisition unit 186 acquires the moving body state information from the power transmission device 200 according to the instruction from the detection unit 180, and supplies the acquired moving body state information to the detection unit 180. When the processing of step S201 is completed, the detection unit 180 determines whether or not the moving body is in the reference region (step S202). For example, the detection unit 180 determines whether or not the position of the moving body indicated by the moving body state information is within the reference region.

When the detection unit 180 determines that the moving body is within the reference region (step S202: YES), the detection unit 180 determines whether or not the moving body is moving (step S203). For example, the detection unit 180 determines whether or not the moving state of the moving body indicated by the moving body state information is moving. The detection unit 180 changes the parameter value to 10 when it is determined that the moving object is not within the reference region (step S202: NO) or when it is determined that the moving object is not moving (step S203: NO). (Step S204).

When the detection unit 180 determines that the moving body is moving (step S203: YES), the detection unit 180 determines whether or not the moving body is moving at a low speed (step S205). For example, the detection unit 180 determines whether or not the moving speed of the moving body indicated by the moving body state information is equal to or less than the first speed threshold value. The first speed threshold value is an upper limit value of the moving speed considered to be low speed. When the detection unit 180 determines that the moving object is moving at a low speed (step S205: YES), the detection unit 180 changes the parameter value to 7 (step S206).

When the detection unit 180 determines that the moving body is not moving at a low speed (step S205: NO), the detection unit 180 determines whether or not the moving body is moving at a medium speed (step S207). For example, the detection unit 180 determines whether or not the moving speed of the moving body indicated by the moving body state information is equal to or less than the second speed threshold value. The second speed threshold value is an upper limit value of the moving speed considered to be medium speed. When the detection unit 180 determines that the moving object is moving at a medium speed (step S207: YES), the detection unit 180 changes the parameter value to 5 (step S208).

When the detection unit 180 determines that the moving body is not moving at a medium speed (step S207: NO), the detection unit 180 executes the installation height-based change process (step S209). The change process for each installation height will be described in detail with reference to the flowchart shown in FIG.

First, the detection unit 180 acquires the installation height information (step S301). For example, the detection unit 180 instructs the height information acquisition unit 187 to acquire the height information. On the other hand, the height information acquisition unit 187 acquires height information from the power transmission device 200 according to the instruction from the detection unit 180, and supplies the acquired height information to the detection unit 180.

When the processing of step S301 is completed, the detection unit 180 determines whether or not the installation height of the power receiving coil 311 is low (step S302). For example, the detection unit 180 determines whether or not the installation height of the power receiving coil 311 indicated by the height information is equal to or less than the first height threshold value. The first height threshold is the upper limit of the installation height considered to be low. When the detection unit 180 determines that the installation height of the power receiving coil 311 is low (step S302: YES), the detection unit 180 changes the parameter value to 2 (step S303).

When the detection unit 180 determines that the installation height of the power receiving coil 311 is not low (step S302: NO), the detection unit 180 determines whether or not the installation height of the power receiving coil 311 is medium (step S304). For example, the detection unit 180 determines whether or not the installation height of the power receiving coil 311 indicated by the height information is equal to or less than the second height threshold value. The second height threshold is the upper limit of the installation height, which is considered to be a medium height. When the detection unit 180 determines that the installation height of the power receiving coil 311 is medium (step S304: YES), the detection unit 180 changes the parameter value to 3 (step S305).

When the detection unit 180 determines that the installation height of the power receiving coil 311 is not medium (step S304: NO), the parameter value is changed to 4 (step S307). When the detection unit 180 completes the processing of step S303, step S305, or step S307, the installation height-based change processing is completed.

When the detection unit 180 completes the processing of step S204, step S206, step S208, or step S209, the first parameter change processing is completed. When the detection unit 180 completes the first parameter change process in step S102, the detection unit 180 executes the second parameter change process (step S103). The second parameter change process will be described in detail with reference to the flowchart shown in FIG.

First, the detection unit 180 acquires the operation state information (step S401). For example, the detection unit 180 instructs the operation state acquisition unit 188 to acquire the operation state information. On the other hand, the operation state acquisition unit 188 acquires the operation state information from the power transmission device 200 according to the instruction from the detection unit 180, and supplies the acquired operation state information to the detection unit 180. When the processing of step S401 is completed, the detection unit 180 determines whether or not the power supply device 220 is in the power transmission stop (step S402). For example, the detection unit 180 determines whether or not the operating state of the power supply device 220 indicated by the operating state information is a state in which power transmission is stopped.

When the detection unit 180 determines that the power supply device 220 is not stopping power transmission (step S402: NO), the detection unit 180 determines whether or not the power supply device 220 is transmitting power with a constant power (step S403). For example, the detection unit 180 determines whether or not the operating state of the power supply device 220 indicated by the operating state information is a state in which power is transmitted with a constant power. When the detection unit 180 determines that the power supply device 220 is in the process of stopping power transmission (step S402: YES), or when the power supply device 220 determines that the power supply device 220 is transmitting power with a constant power (step S403: YES). , The provisional value is changed to 10 (step S404). This provisional value is a provisional value of the parameter value.

When the detection unit 180 determines that the power supply device 220 is not transmitting power at a constant power (step S403: NO), the detection unit 180 determines whether or not the transmitted power is significantly increasing or decreasing (step S405). For example, the detection unit 180 determines whether or not the operating state of the power supply device 220 indicated by the operating state information is a state in which power is transmitted while the transmitted power is significantly increased or decreased. When the detection unit 180 determines that the transmitted power is significantly increasing or decreasing (step S405: YES), the detection unit 180 changes the provisional value to 3 (step S406).

When the detection unit 180 determines that the transmitted power is not significantly increasing or decreasing (step S405: NO), it determines whether or not the transmitted power is moderately increasing or decreasing (step S407). For example, the detection unit 180 determines whether or not the operating state of the power supply device 220 indicated by the operating state information is a state in which power is transmitted while the transmitted power is moderately increased or decreased. When the detection unit 180 determines that the transmitted power is moderately increasing or decreasing (step S407: YES), the detection unit 180 changes the provisional value to 5 (step S408). When the detection unit 180 determines that the transmitted power is not increasing or decreasing moderately (step S407: NO), the detection unit 180 changes the provisional value to 7 (step S409).

When the detection unit 180 completes the processing of step S404, step S406, step S408, or step S409, the detection unit 180 determines whether or not the provisional value is less than the parameter value (step S410). When the detection unit 180 determines that the provisional value is less than the parameter value (step S410: YES), the detection unit 180 changes the parameter value to the provisional value (step S411).

At the time when step S410 is executed, the parameter value is a value set according to the state of the moving body and the installation height of the power receiving coil 311, and the provisional value is according to the operating state of the power supply device 220. It is a value set in. Therefore, the smaller of these two values is adopted as the parameter value. That is, the smaller value is adopted as the parameter value so that the threshold value follows the predicted change of the earliest output value. When the detection unit 180 determines that the provisional value is not less than the parameter value (step S410: NO), or when the process of step S411 is completed, the detection unit 180 completes the second parameter change process.

When the detection unit 180 completes the second parameter change process in step S103, the detection unit 180 executes the third parameter change process (step S104). The third parameter change process will be described in detail with reference to the flowchart shown in FIG.

First, the detection unit 180 acquires temperature information (step S501). For example, the detection unit 180 instructs the temperature information acquisition unit 189 to acquire the temperature information. On the other hand, the temperature information acquisition unit 189 acquires temperature information from the power transmission device 200 according to the instruction from the detection unit 180, and supplies the acquired temperature information to the detection unit 180. When the processing of step S501 is completed, the detection unit 180 determines whether or not the temperature of the specific portion is a moderate temperature (step S502). For example, the detection unit 180 determines whether or not the temperature of the specific portion indicated by the temperature information exceeds the first temperature threshold value and is equal to or lower than the second temperature threshold value. The first temperature threshold is the upper limit of the temperature considered to be low. The second temperature threshold is the upper limit of the temperature considered to be moderate.

When the detection unit 180 determines that the temperature of the specific portion is not a medium temperature (step S502: NO), the detection unit 180 determines whether or not the temperature of the specific portion is high (step S503). For example, the detection unit 180 determines whether or not the temperature of the specific portion indicated by the temperature information exceeds the second temperature threshold value. When the detection unit 180 determines that the temperature of the specific portion is high (step S503: YES), the detection unit 180 sets a value obtained by adding 3 to the parameter value as a provisional value (step S504). When the detection unit 180 determines that the temperature of the specific portion is not high (step S503: NO), the detection unit 180 sets a value obtained by adding 1 to the parameter value as a provisional value (step S505).

When the processing of step S504 or step S505 is completed, the detection unit 180 determines whether or not the provisional value is equal to or less than the upper limit value (step S506). This upper limit is the upper limit of the parameter value. When the detection unit 180 determines that the provisional value is equal to or less than the upper limit value (step S506: YES), the detection unit 180 changes the parameter value to the provisional value (step S507). On the other hand, when the detection unit 180 determines that the provisional value is not equal to or less than the upper limit value (step S506: NO), the detection unit 180 changes the parameter value to the upper limit value (step S508).

When the detection unit 180 determines that the temperature of the specific portion is a medium temperature (step S502: YES), or when the process of step S507 or step 508 is completed, the detection unit 180 completes the third parameter change process. When the detection unit 180 completes the third parameter change process in step S104, the detection unit 180 selects the sensor coil 120 (step S105). For example, the detection unit 180 selects one sensor coil 120 from the 12 sensor coils 120 according to a predetermined order. When the detection unit 180 completes the process of step S105, the detection unit 180 executes the output value acquisition process (step S106). The output value acquisition process will be described in detail with reference to the flowchart shown in FIG.

First, the detection unit 180 controls the states of the switches 132 and 133 (step S601). That is, the detection unit 180 controls the switch control unit 182 to control the switch 132 and the switch 133 included in the selected sensor coil 120 to be in the ON state, and the switch 132 and the switch included in the sensor coil 120 not selected. The 133 is controlled to the off state.

When the detection unit 180 completes the process of step S601, the detection unit 180 applies a pulsed voltage to the selected sensor coil 120 (step S602). That is, the detection unit 180 controls the pulse control unit 181 to generate a pulse-shaped voltage in the pulse generation unit 140. When the processing of step S602 is completed, the detection unit 180 acquires an output value from the selected sensor coil 120 (step S603). The detection unit 180 acquires an output value from the selected sensor coil 120 via the output value acquisition unit 183. When the detection unit 180 completes the process of step S603, the output value acquisition process is completed.

When the detection unit 180 completes the output value acquisition process in step S106, the detection unit 180 determines whether or not the output value exceeds the threshold value (step S107). When the detection unit 180 determines that the output value does not exceed the threshold value (step S107: NO), the detection unit 180 calculates the value of the moving average of the output values (step S108). That is, the detection unit 180 calculates the moving average value of the number of output values corresponding to the parameter values selected in order from the newest output value acquired for the selected sensor coil 120.

When the detection unit 180 completes the process of step S108, the detection unit 180 corrects the threshold value based on the value of the moving average (step S109). That is, the detection unit 180 sets the value obtained by adding the offset value to the value of the moving average calculated for the selected sensor coil 120 as a new threshold value of the selected sensor coil 120. When the processing of step S109 is completed, the detection unit 180 determines whether or not all the sensor coils 120 have been selected (step S110).

When the detection unit 180 determines that all the sensor coils 120 have not been selected (step S110: NO), the processing is returned to step S105, the unselected sensor coils 120 are selected, and the subsequent processing is executed. When the detection unit 180 determines that all the sensor coils 120 have been selected (step S110: YES), the detection unit 180 returns the process to step S102.

When the detection unit 180 determines that the output value exceeds the threshold value (step S107: YES), the detection unit 180 notifies the user of foreign matter detection (step S111). For example, the detection unit 180 instructs the notification unit 184 to notify. The notification unit 184 transmits information indicating that the foreign matter 10 has been detected to the terminal device 800 according to the instruction from the detection unit 180. On the other hand, when the terminal device 800 receives this information, the terminal device 800 notifies the user that the foreign matter 10 has been detected by displaying the screen, outputting voice, or the like. When the user is notified by the terminal device 800 that the foreign matter 10 is present, the user removes the foreign matter 10.

When the detection unit 180 completes the process of step S111, the detection unit 180 instructs the power supply device 220 to stop power transmission (step S112). For example, the detection unit 180 instructs the power transmission control unit 185 to stop power transmission. The power transmission control unit 185 transmits information instructing the power supply device 220 to stop power transmission according to the instruction from the detection unit 180. On the other hand, when the power supply device 220 receives this information, the power supply device 220 stops power transmission. When the processing of step S112 is completed, the detection unit 180 completes the foreign matter detection processing.

In this embodiment, the threshold value is corrected based on the output value and the parameter value. That is, in the present embodiment, the threshold value is corrected according to the output value that changes according to the change in the environment surrounding the foreign matter detecting device 100. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy in the foreign matter detection of wireless power transmission.

Further, in the present embodiment, the parameter value is changed according to the state of the moving body indicated by the moving body state information. Therefore, according to the present embodiment, when the output value changes at a speed corresponding to the state of the moving body, erroneous detection and omission of detection are suppressed, and the foreign matter 10 is detected with high accuracy.

Further, in the present embodiment, when the state of the moving body changes to the first state in which the position of the moving body is within the reference region and the moving state of the moving body is in the moving state, the parameter value is changed. .. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the state of the moving body is the first state and the output value changes rapidly.

Further, in the present embodiment, when the state of the moving body is the first state, the parameter value is changed according to the moving speed of the moving body. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes at a speed corresponding to the moving speed of the moving body.

Further, in the present embodiment, when the state of the moving body is the first state, the parameter value is changed according to the installation height of the power receiving coil 311. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes at a speed corresponding to the installation height of the power receiving coil 311.

Further, in the present embodiment, the parameter value is changed according to the operating state of the power supply device 220. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes at a speed corresponding to the operating state of the power supply device 220.

Further, in the present embodiment, the parameter value is changed according to the amount of change in the magnitude of the AC power supplied from the power supply device 220 to the power transmission coil 211 per unit time. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes at a speed corresponding to the speed of change of the transmitted power.

Further, in the present embodiment, the parameter value is changed according to the temperature of the specific part of the power transmission device 200. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes at a speed corresponding to the temperature of the specific portion of the power transmission device 200.

Further, in the present embodiment, the value of the moving average of the number of output values indicated by the parameter values, which has been acquired most recently, is used to correct the threshold value. That is, in the present embodiment, the threshold value follows the output value at a speed appropriately adjusted by the parameter value. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes according to the change in the environment surrounding the foreign matter detecting device 100.

(Embodiment 2)
In the first embodiment, an example in which the threshold value is changed based on the output value and the parameter value has been described. In the present embodiment, an example will be described in which not only the threshold value is changed based on the output value and the parameter value, but also the threshold value is changed based on the state of the moving body and the operating state of the power supply device 220. .. The description of the same configuration and processing as in the first embodiment will be omitted or simplified.

In the present embodiment, the detection unit 180 changes the threshold value based on the state of the moving body indicated by the moving body state information before executing the threshold value correction process. For example, the detection unit 180 changes the threshold value immediately after the foreign matter detection process is started, based on the state of the moving body indicated by the moving body state information.

Further, the detection unit 180 changes the threshold value based on the operating state of the power supply device 220 indicated by the operating state information before executing the threshold value correction process. For example, the detection unit 180 changes the threshold value immediately after the foreign matter detection process is started, based on the operating state of the power supply device 220 indicated by the operating state information.

Hereinafter, the threshold value change process executed by the foreign matter detection device 100 according to the present embodiment will be described with reference to FIG. The threshold value change process is executed, for example, after the initial setting in step S101 is completed.

First, the detection unit 180 included in the foreign matter detection device 100 acquires the moving body state information (step S701). For example, the detection unit 180 instructs the moving body state acquisition unit 186 to acquire the moving body state information, and acquires the moving body state information from the moving body state acquisition unit 186. When the detection unit 180 completes the process of step S702, the detection unit 180 acquires the operation state information (step S702). For example, the detection unit 180 instructs the operation state acquisition unit 188 to acquire the operation state information, and acquires the operation state information from the operation state acquisition unit 188.

When the detection unit 180 completes the process of step S703, the detection unit 180 selects the sensor coil 120 (step S703). When the process of step S704 is completed, the detection unit 180 changes the threshold value of the selected sensor coil 120 based on the moving body state information and the operating state information for the selected sensor coil 120.

It is considered that the output value acquired when there is no foreign matter 10 depends on the state of the moving body and the operating state of the power supply device 220. Further, it is considered that the output value acquired when there is no foreign matter 10 is different for each sensor coil 120. Therefore, the output value acquired when there is no foreign matter 10 is obtained in advance by experiments, simulations, etc. for each combination of the state of the moving body, the operating state of the power supply device 220, and the individual sensor coil 120. It is preferable to obtain the initial value of the threshold value based on the obtained output value. Then, the storage unit 150 stores the initial value information indicating the initial value of the threshold value for each of the above combinations. The detection unit 180 changes the threshold value of the selected sensor coil 120 to the initial value of the threshold value indicated by the initial value information.

When the processing of step S704 is completed, the detection unit 180 determines whether or not all the sensor coils 120 have been selected (step S705). When the detection unit 180 determines that all the sensor coils 120 have not been selected (step S705: NO), the process returns to step S703 and selects the unselected sensor coils 120. On the other hand, when the detection unit 180 determines that all the sensor coils 120 have been selected (step S705: YES), the detection unit 180 completes the threshold value change process and returns the process to step S102.

In the present embodiment, the threshold value is changed based on the state of the moving body before the threshold value correction process is executed. Therefore, according to the present embodiment, the threshold value to be compared with the output value can be quickly changed to the threshold value suitable for the state of the moving body.

Further, in the present embodiment, the threshold value is changed based on the operating state of the power supply device 220 before the threshold value correction process is executed. Therefore, according to the present embodiment, the threshold value to be compared with the output value can be quickly changed to the threshold value suitable for the operating state of the power supply device 220.

(Embodiment 3)
In the first embodiment, an example in which the correction parameter is the number of output values used when obtaining the moving average of the output values has been described. In this embodiment, an example in which the correction parameter is a weighting coefficient used when weighting the output value will be described.

In the present embodiment, the detection unit 180 corrects the threshold value in the threshold value correction process by using a value obtained by multiplying the most recently acquired output value by the weighting coefficient indicated by the parameter value. For example, the detection unit 180 uses a value obtained by adding the first value, the second value, and the offset value as a new threshold value. The first value is a value obtained by multiplying the most recently acquired output value by the weight count indicated by the parameter value. The second value is a value obtained by multiplying the value obtained by subtracting the offset value from the threshold value before correction by the value obtained by subtracting the weight count indicated by the parameter value from 1.

Here, for example, it is assumed that the most recently acquired output value is 4 (V), the threshold value before correction is 3 (V), and the offset value is 1 (V). In this case, when the parameter value is 0.1, the first value is 0.4 (V), the second value is 1.8 (V), and the new threshold value is 3.2 (V). .. On the other hand, when the parameter value is 0.5, the first value is 2 (V), the second value is 1 (V), and the new threshold value is 4 (V). As described above, in the present embodiment, the larger the parameter value, the faster the threshold value follows the output value.

In the present embodiment, the threshold value is corrected by using the value obtained by multiplying the most recently acquired output value by the weighting coefficient indicated by the parameter value. That is, in the present embodiment, the threshold value follows the output value at a speed appropriately adjusted by the parameter value. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes according to the change in the environment surrounding the foreign matter detecting device 100.

(Embodiment 4)
In the first embodiment, an example in which the parameter value is changed according to the temperature of a specific part has been described. In this embodiment, an example in which the parameter value is changed according to the amount of fluctuation in the temperature of a specific part will be described. The description of the same configuration and processing as those of the first to third embodiments will be omitted or simplified.

In the present embodiment, the detection unit 180 changes the parameter value according to the amount of fluctuation in the temperature of the specific portion indicated by the temperature information acquired by the temperature information acquisition unit 189. That is, the detection unit 180 changes the parameter value according to the easiness of fluctuation of the output value according to the fluctuation amount of the temperature of the specific portion of the power transmission device 200. A large fluctuation in the temperature of a specific part means that the temperature of the specific part fluctuates greatly in a short time. On the other hand, the fact that the amount of fluctuation in the temperature of the specific part is small means that the temperature of the specific part does not fluctuate much. The correspondence between the amount of temperature fluctuation of the specific portion of the power transmission device 200 and the parameter value can be appropriately adjusted. In the present embodiment, as shown in FIG. 19, the correspondence between the temperature fluctuation amount of the specific portion of the power transmission device 200 and the parameter value is defined by the fourth parameter table stored in the storage unit 150.

According to the 4th parameter table, the parameter value is not changed when the amount of temperature fluctuation of a specific part is large. That is, when the amount of fluctuation in the temperature of a specific part is large, parameter values corresponding to other factors are set. Further, when the amount of fluctuation in the temperature of the specific portion is medium, the parameter value is added by 1. That is, when the amount of fluctuation in the temperature of the specific portion is medium, the value obtained by adding 1 to the parameter value corresponding to the other elements is set as the parameter value. Further, when the amount of fluctuation in the temperature of the specific portion is small, the parameter value is added by 3. That is, when the fluctuation amount of the temperature of the specific portion is small, the value obtained by adding 3 to the parameter value corresponding to other elements is set as the parameter value.

In the present embodiment, the parameter value is changed according to the amount of fluctuation in the temperature of the specific part of the power transmission device 200. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy when the output value changes at a speed corresponding to the fluctuation amount of the temperature of the specific portion in the power transmission device 200.

(Embodiment 5)
In Embodiment 1-4, an example in which the foreign matter detecting device 100 is provided in the power transmission device 200 has been described. In this embodiment, an example in which the power receiving device 300 is provided with the foreign matter detecting device 100 will be described. The description of the same configuration and processing as those of the first and fourth embodiments will be omitted or simplified.

As shown in FIG. 20, the detection coil unit 110 is formed in a flat plate shape and is arranged on the power receiving coil unit 310 so as to overlap the power receiving coil 311 in a plan view. The pulse generation unit 140 generates a pulse-shaped voltage for detecting foreign matter, and selects and applies the sensor coil 120.

The detection unit 180 determines the presence or absence of the foreign matter 10 based on the comparison result between the output value of the sensor coil 120 excited by the application of the pulsed voltage and the threshold value. The detection unit 180 executes a threshold value correction process for correcting the threshold value based on the output value and the parameter value which is the value of the correction parameter used for the correction of the threshold value.

In the present embodiment, the power receiving device 300 is provided with the foreign matter detecting device 100, and the threshold value is corrected based on the output value and the parameter value. That is, in the present embodiment, even when the foreign matter detecting device 100 is provided in the power receiving device 300 from various viewpoints, the threshold value is set according to the output value that changes according to the change in the environment surrounding the foreign matter detecting device 100. It will be corrected. Therefore, according to the present embodiment, the foreign matter 10 is detected with high accuracy in the foreign matter detection of wireless power transmission.

(Modification example)
Although the embodiments of the present disclosure have been described above, various modifications and applications are possible in carrying out the present disclosure. In the present disclosure, it is arbitrary which part of the configuration, function, and operation described in the above embodiment is adopted. Further, in the present disclosure, in addition to the above-mentioned configurations, functions, and operations, further configurations, functions, and operations may be adopted. In addition, the above embodiments can be freely combined as appropriate. In addition, the number of components described in the above embodiment can be appropriately adjusted. Further, it goes without saying that the materials, sizes, electrical characteristics, and the like that can be adopted in the present disclosure are not limited to those shown in the above embodiments.

In the first embodiment, an example in which an independent threshold value and an initial value of the independent threshold value are prepared for each of the plurality of sensor coils 120 has been described. A common threshold value and an initial value of the common threshold value may be prepared for the plurality of sensor coils 120. In this case, the moving average value may be obtained for the output value acquired for one sensor coil 120, or the moving average value may be obtained for the output value acquired for the plurality of sensor coils 120. May be done.

In the first embodiment, an example in which a plurality of sensor coils 120 are used as sensors used for detecting foreign matter has been described. One sensor coil 120 may be used as the sensor used for detecting foreign matter. In the first embodiment, an example in which the sensor coil 120 is used as the sensor used for detecting foreign matter has been described. As the sensor used for detecting foreign matter, various sensors such as a temperature sensor and an ultrasonic sensor may be used.

In the first embodiment, the smaller of the parameter value based on the state of the moving body and the parameter value based on the operating state of the power supply device 220 is added to the parameter value based on the temperature of the specific part. Has described an example of being determined as a new parameter value. The method of determining the parameter value is not limited to this example. For example, a parameter value may be prepared for each combination of the state of the moving body and the like, the operating state of the power supply device 220, and the temperature of the specific portion. Further, even if the smallest parameter value among the parameter value based on the state of the moving body, the parameter value based on the operating state of the power supply device 220, and the parameter value based on the temperature of the specific part is determined as a new parameter value. good.

Further, in the first embodiment, an example in which the parameter value is changed for each of the three elements of the state of the moving body, the operating state of the power supply device 220, and the temperature of the specific part has been described. The parameter value may be changed for two of these elements, or the parameter value may be changed for one of these elements.

In the first embodiment, the power transmission device 200 acquires various information such as moving body state information, height information, operating state information, temperature information, and the foreign matter detection device 100 acquires various information from the power transmission device 200. An example was explained. The foreign matter detection device 100 may acquire various information from a device other than the power transmission device 200. For example, a temperature sensor 260 may be provided in the foreign matter detection device 100, and the foreign matter detection device 100 may acquire temperature information from the temperature sensor 260. Further, the foreign body detecting device 100 may acquire the moving body state information and the height information from the communication device 600. Further, the foreign body detection device 100 or the power transmission device 200 may acquire the moving body state information and the height information from a device other than the communication device 600. For example, the foreign matter detection device 100 or the power transmission device 200 may acquire the moving body state information from the image pickup device installed in the power supply equipment and the height information from the proximity sensor installed in the power supply equipment.

In the first embodiment, when the moving speed of the moving body is medium speed or low speed, an example in which the installation height of the power receiving coil 311 is not taken into consideration has been described. Even when the moving speed of the moving body is medium or low, the installation height of the power receiving coil 311 may be taken into consideration as in the case where the moving speed of the moving body is high.

In the first embodiment, an example has been described in which the acquisition cycle in which the output value of one sensor coil 120 is acquired and the change cycle in which the parameter value is changed are the same. The change cycle may be longer than the acquisition cycle. Further, the parameter value may be changed when it is detected that the state of the moving body, the operating state of the power supply device 220, the temperature of the specific portion, or the like has changed.

In the first embodiment, an example in which the specific portion where the temperature is measured by the temperature information acquisition unit 189 is a part of the power transmission device 200 in which the foreign matter detection device 100 is incorporated has been described. For example, when the foreign matter detecting device 100 is incorporated in the power receiving device 300, the specific portion may be a part of the power receiving device 300 in which the foreign matter detecting device 100 is incorporated. That is, it is preferable that the specific portion is a part of any one of the foreign matter detection device 100, the power transmission device 200, and the power receiving device 300.

By applying an operation program that regulates the operation of the foreign matter detection device 100 according to the present disclosure to a computer such as an existing personal computer or an information terminal device, the computer can be made to function as the foreign matter detection device 100 according to the present disclosure. It is possible. Further, the distribution method of such a program is arbitrary, and for example, a computer-readable recording such as a CD-ROM (CompactDiskROM), a DVD (DigitalVersatileDisk), an MO (MagnetoOpticalDisk), or a memory card. It may be stored in a medium and distributed, or may be distributed via a communication network such as the Internet.

The present disclosure allows for various embodiments and variations without departing from the broad spirit and scope of the present disclosure. Moreover, the above-described embodiment is for explaining the present disclosure, and does not limit the scope of the present disclosure. That is, the scope of the present disclosure is shown not by the embodiment but by the scope of claims. And various modifications made within the scope of the claims and within the scope of the equivalent disclosure are considered to be within the scope of the present disclosure.

10 Foreign matter 100 Foreign matter detection device 110

Detection coil unit

120, 120A, 120B, 120C, 120D, 120E, 120F, 120G, 120H, 120I, 120J, 120K, 120L Sensor coil 130 Detection coil board 131

Capsule

132, 133 Switch 140

Pulse generation Unit

150, 230

Storage unit

160, 240

1st communication unit

170, 250 2nd communication unit 180 Detection unit 181 Pulse control unit 182 Switch control unit 183 Output value acquisition unit 184 Notification unit 185

Transmission control unit

186, 273 Moving object status acquisition Unit 187,274 Height information acquisition unit 188,272 Operation status acquisition unit 189,277 Temperature information acquisition unit 200 Transmission coil unit 211 Transmission coil unit 211 Transmission coil 220 Power supply device 260 Temperature sensor 270 Control unit 271 Transmission control unit 275 Control information Receiver 276 Information transfer unit 300 Power receiving device 310 Power receiving coil unit 311 Power receiving coil 312 Magnetic plate 320 Rectifier circuit 400 Commercial power supply 500 Storage battery 600 Communication device 700 Electric vehicle 800 Terminal device 1000 Power transmission system

Claims

With the sensor
A detection unit for determining the presence or absence of a foreign substance based on the comparison result between the output value of the sensor and the threshold value is provided.
The detection unit executes a threshold value correction process for correcting the threshold value based on the output value and the parameter value which is the value of the correction parameter used for the correction of the threshold value.
Foreign matter detector.
A moving body state acquisition unit that acquires moving body state information indicating the state of the moving body including the position of the moving body equipped with the power receiving device that wirelessly receives power from the power transmitting device provided with the power transmission coil and the moving state of the moving body. Further preparation,
The detection unit changes the parameter value according to the state of the moving body indicated by the moving body state information acquired by the moving body state acquisition unit.
The foreign matter detection device according to claim 1.
The detection unit changes the state of the moving body indicated by the moving body state information to the first state in which the position of the moving body is within the reference region and the moving state of the moving body is in the moving state. , Change the parameter value,
The foreign matter detection device according to claim 2.
When the state of the moving body indicated by the moving body state information is the first state, the detection unit changes the parameter value according to the moving speed of the moving body.
The foreign matter detection device according to claim 3.
Further, a height information acquisition unit for acquiring height information indicating the installation height of the power receiving coil provided in the power receiving device is provided.
When the state of the moving body indicated by the moving body state information is the first state, the detection unit responds to the installation height of the power receiving coil indicated by the height information acquired by the height information acquisition unit. To change the parameter value,
The foreign matter detection device according to claim 3 or 4.
The detection unit changes the threshold value based on the state of the moving body indicated by the moving body state information before executing the threshold value correction process.
The foreign matter detection device according to any one of claims 2 to 5.
It is further equipped with an operating state acquisition unit that acquires operating state information indicating the operating state of the power supply device that supplies AC power to the power transmitting coil of the power transmitting device that wirelessly transmits power to the power receiving device equipped with the power receiving coil.
The detection unit changes the parameter value according to the operation state of the power supply device indicated by the operation state information acquired by the operation state acquisition unit.
The foreign matter detection device according to any one of claims 1 to 6.
The detection unit changes the parameter value according to the amount of change in the magnitude of the AC power supplied from the power supply device to the power transmission coil per unit time.
The foreign matter detection device according to claim 7.
The detection unit changes the threshold value based on the operating state of the power supply device indicated by the operating state information before executing the threshold value correction process.
The foreign matter detecting device according to claim 7 or 8.
Further equipped with a temperature information acquisition unit that acquires temperature information indicating the temperature of a specific part,
The detection unit changes the parameter value according to the temperature of the specific portion or the fluctuation amount of the temperature of the specific portion indicated by the temperature information acquired by the temperature information acquisition unit.
The foreign matter detection device according to any one of claims 1 to 9.
The correction parameter is the number of the output values used when obtaining the moving average of the output values.
The detection unit corrects the threshold value by using the moving average value of the output value corresponding to the number indicated by the parameter value, which was acquired most recently in the threshold value correction process.
The foreign matter detection device according to any one of claims 1 to 10.
The correction parameter is a weighting coefficient used when weighting the output value.
In the threshold value correction process, the detection unit corrects the threshold value by using a value obtained by multiplying the most recently acquired output value by a weighting coefficient indicated by the parameter value.
The foreign matter detection device according to any one of claims 1 to 11.
The foreign matter detection device according to any one of claims 1 to 12, and the foreign matter detection device.
A power transmission coil composed of wound conductors and
A power supply device for supplying AC power to the power transmission coil is provided.
Power transmission device.
The foreign matter detection device according to any one of claims 1 to 12, and the foreign matter detection device.
A power receiving coil composed of wound conductors and
A rectifier circuit for rectifying the AC power received by the power receiving coil is provided.
Power receiving device.
The power transmission device according to claim 13 and
A power receiving device that receives power from the power transmitting device, and the like.
Power transmission system.
The power receiving device according to claim 14,
A power transmission device for transmitting power to the power receiving device, and the like.
Power transmission system.