WO2022144993A1 - Foreign object detection device, power transmission device, power reception device, and power transmission system - Google Patents

Abstract

A sensor coil (120A) has an opening portion (123A). A sensor coil (120B) has an opening portion (123B) that is larger than the opening portion (123A) when viewed from a first direction in which the winding axis of the sensor coil (120A) extends. On the basis of signals output from the sensor coil (120A) and the sensor coil (120B), a detection unit detects a foreign object that is present in a foreign object detection region. The sensor coil (120A) is disposed at a position where at least a part of the opening portion (123A) overlaps with the opening portion (123B) when viewed from the first direction.

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.

Patent Document 1 describes a detection device that determines the presence or absence of a foreign substance that generates heat due to magnetic flux from a change in electrical parameters related to a magnetic coupling element that is a detection coil or a circuit including the magnetic coupling element. It is desirable that such a foreign matter detecting device is formed so as to be able to detect foreign matter in a wide range without leakage. In the detection device described in Patent Document 1, a large number of detection coils of the same size are arranged in two or more layers so that a dead region, which is a region where foreign matter cannot be detected, does not occur between adjacent detection coils. There is.

Japanese Unexamined Patent Publication No. 2013-192391

However, it is considered that the detection device described in Patent Document 1 cannot detect foreign matter in a wide range without omission and can also detect small foreign matter. That is, the small size detection coil is advantageous for detecting a small foreign substance, but is disadvantageous for detecting a distant foreign substance. On the other hand, the large size detection coil is advantageous for detecting a distant foreign matter, but is disadvantageous for detecting a small foreign matter. Therefore, even if a large number of small size detection coils are arranged over two or more layers, it is difficult to detect a distant foreign matter. On the other hand, even if a large number of detection coils having a large size are arranged over two or more layers, it is difficult to detect a small foreign substance. Therefore, in wireless power transmission, there is a demand for a technique for detecting foreign matter in a wide range without leakage and also detecting small foreign matter.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to detect foreign matter in a wide range without omission and also to detect small 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
A first sensor coil with a first opening and
A second sensor coil having a second opening larger than the first opening when viewed from the first direction in which the winding shaft of the first sensor coil extends.
A detection unit that detects foreign matter existing in the foreign matter detection region based on the signals output from the first sensor coil and the second sensor coil is provided.
The first sensor coil is arranged at a position where at least a part of the first opening is overlapped with the second opening when viewed from the first direction.

According to the foreign matter detection device having the above configuration, in wireless power transmission, foreign matter can be detected in a wide range without omission, and even small foreign matter can be detected.

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 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. Explanatory diagram of the positional relationship of the loop coil Sectional drawing of line AA in FIG. Configuration diagram of the detection unit included in the foreign matter detection device according to the first embodiment. Top view of the detection coil unit according to the second embodiment Sectional drawing of line BB in FIG. Enlarged sectional view showing a part of the sectional view shown in FIG. Top view of the detection coil unit according to the third embodiment Top view of the detection coil unit according to the fourth embodiment An explanatory diagram of the positional relationship between the first sensor coil and the second sensor coil according to the fifth embodiment. Top view of the detection coil unit according to the sixth embodiment Layout of the foreign matter detection device according to the seventh 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.

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 portion in the central portion. May be done.

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 has a plate shape with a hole in the center 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 portion in the central portion. May be done.

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 terminal device 600 is a device that receives a notification from the foreign matter detecting device 100 that there is a foreign matter. The terminal device 600 is, for example, a smartphone owned by the owner of the electric vehicle 700. When the terminal device 600 receives a notification from the foreign matter detecting device 100 that there is a foreign matter, the terminal device 600 notifies the user that the foreign matter is present by displaying a screen, outputting a 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 includes a detection coil unit 110, a detection unit 150, a pulse generation unit 160, and a notification unit 170.

The detection coil unit 110 is a unit that detects foreign matter. As shown in FIG. 3, 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. Note that FIG. 3 is a plan view of the detection coil unit 110. The detection coil unit 110 includes a detection coil substrate 140 made of a permeable magnetic material typified by resin.

A plurality of sensor coils 120A, a plurality of sensor coils 120B, and an external connector 145 connecting each sensor coil 120, the detection unit 150, and the pulse generation unit 160 are mounted on the detection coil board 140. The sensor coil 120 is a general term for the sensor coil 120A and the sensor coil 120B. In FIG. 3, the reference numerals of the sensor coil 120A, the sensor coil 120B, and the like are omitted as appropriate. Also in the following drawings, reference numerals are omitted as appropriate from the viewpoint of legibility.

The detection unit 150 determines whether or not a foreign substance is present in the detection target region based on the output value of the sensor coil 120 excited by the application of the pulsed voltage. The pulse generation unit 160 generates a pulse-shaped voltage for detecting foreign matter, and selects and applies the sensor coil 120. When the detection unit 150 detects a foreign substance, the notification unit 170 notifies the user that the foreign substance has been detected. For example, the notification unit 170 transmits information indicating that a foreign object has been detected to the terminal device 600 possessed by the user.

Next, the configuration and arrangement of the sensor coil 120 will be described with reference to FIGS. 3, 4, 5, and 6. FIG. 4 is a diagram showing an equivalent circuit of the resonance circuit included in the detection coil unit 110. FIG. 5 is an explanatory diagram of the positional relationship of the sensor coil 120. FIG. 6 is a cross-sectional view taken along the line AA in FIG.

As shown in FIG. 4, the 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 wound once or a plurality of times around an axis parallel to the Z axis on the upper surface of the detection coil substrate 140. 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 generation unit 160 via the external connector 145. 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 generator 160 via the external connector 145. 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 detection unit 150 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 130. The switch 133 has a function of switching the state between the resonance circuit and the pulse generating unit 160.

That is, when both the switch 132 and the switch 133 are turned on, the sensor coil 120 and the capacitor 131 form a resonance circuit, and the resonance circuit is pulsed from the pulse generator 160 via the external connection connector 145. A voltage is applied. 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 detection unit 150 via the external connector 145. 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 detection unit 150 and the pulse generation unit 160.

FIG. 4 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, and the switch 133 is closed and a pulse voltage is applied from the pulse generating unit 160. 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 150 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.

Here, the size of the foreign matter 10 that is easy to detect differs from the size of the foreign matter 10 that is easy to detect, depending on the size of the sensor coil 120. For example, the large sensor coil 120 can easily detect the large foreign matter 10 arranged far away, but it is difficult to detect the small foreign matter 10. On the other hand, the small sensor coil 120 can easily detect the small foreign matter 10, but it is difficult to detect the foreign matter 10 arranged far away.

That is, it is preferable that the foreign matter 10 arranged far away is detected by the large sensor coil 120, and the small foreign matter 10 is detected by the small sensor coil 120. Therefore, in the present embodiment, by appropriately arranging the plurality of large sensor coils 120 and the plurality of small sensor coils 120, the foreign matter 10 is detected in a wide range without leakage, and the small foreign matter 10 is also detected. Hereinafter, the arrangement of the sensor coil 120 according to the present embodiment will be described in detail with reference to FIG.

The sensor coil 120A is a coil in which a coil conductor 121A is wound around a shaft 124A. In the present embodiment, the coil conductor 121A is a conductor pattern mounted on the upper surface of the detection coil substrate 140, and is a conductor pattern having loops for two rounds. The sensor coil 120A has an opening 123A. The opening portion 123A is an opening portion formed inside the coil conductor 121A, and is a portion corresponding to the region 125A surrounded by the broken line. The shaft 124A is a winding shaft of the sensor coil 120A. The sensor coil 120A is an example of the first sensor coil. The opening 123A is an example of the first opening.

The sensor coil 120B is a coil in which a coil conductor 121B is wound around a shaft 124B. In the present embodiment, the coil conductor 121B is a conductor pattern mounted on the lower surface of the detection coil substrate 140, and is a conductor pattern having loops for two rounds. The sensor coil 120B has an opening 123B. The opening 123B is an opening formed inside the coil conductor 121B, and is a portion corresponding to the region 125B surrounded by the broken line.

The shaft 124B is a winding shaft of the sensor coil 120B. The shaft 124A and the shaft 124B are parallel to each other, and the shaft 124A and the shaft 124B extend in the Z-axis direction. Here, the opening 123B is larger than the opening 123A when viewed from the first direction in which the shaft 124A extends. That is, the region 125B is larger than the region 125A. The first direction is the Z-axis direction. The sensor coil 120B is an example of the second sensor coil. The opening 123B is an example of the second opening.

Here, the sensor coil 120A is arranged at a position where at least a part of the opening 123A overlaps with the opening 123B when viewed from the first direction. That is, at least a part of the region 125A overlaps with the region 125B. According to such a configuration, the sensor coil 120A detects a nearby foreign matter 10 arranged in the positive direction of the Z axis when viewed from the region where the region 125A and the region 125B overlap. Further, when viewed from the region where the region 125A and the region 125B overlap, the distant foreign matter 10 arranged in the positive direction of the Z axis is detected by the sensor coil 120A. That is, according to such a configuration, both the near foreign matter 10 and the distant foreign matter 10 are detected, and the foreign matter 10 is detected in a wide range without omission.

Further, in the present embodiment, the entire opening 123A overlaps the opening 123B when viewed from the first direction, and the entire region 125A overlaps the region 125B. According to such a configuration, the influence of the coil conductor 121B is small when the foreign matter 10 is detected by the sensor coil 120A. Therefore, according to this configuration, the foreign matter 10 is detected with high accuracy by the sensor coil 120A.

Further, in the present embodiment, as shown in FIG. 3, four sensor coils 120B are mounted in two rows × two rows on the upper surface of the detection coil substrate 140, and four are inside each of the four sensor coils 120B. 16 sensor coils 120A are mounted in 4 rows × 4 rows on the upper surface of the detection coil substrate 140 so that the sensor coils 120A are arranged in 2 rows × 2 rows. That is, the number of sensor coils 120A is 16, and the number of sensor coils 120B is 4. As described above, in the present embodiment, the number of sensor coils 120A is larger than the number of sensor coils 120B. Then, in the present embodiment, each of the plurality of sensor coils 120B has an opening 123B having an opening 123A of each of at least two sensor coils 120A among the plurality of sensor coils 120A when viewed from the first direction. It is placed in an overlapping position.

According to such a configuration, a relatively large number of sensor coils 120A can detect a nearby foreign matter 10 without omission, and a relatively small number of sensor coils 120B can detect a distant foreign matter 10. That is, according to such a configuration, the foreign matter 10 is efficiently detected in a wide range without leakage with a small number of sensor coils 120.

Further, in the present embodiment, as shown in FIG. 6, the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged on the same surface. That is, on the upper surface 141 of the detection coil substrate 140, a plurality of coil conductors 121A each constituting a plurality of sensor coils 120A and a plurality of coil conductors 121B constituting each of the plurality of sensor coils 120B are arranged. The upper surface 141 is one of the two surfaces of the detection coil substrate 140. Further, the lower surface 142 is the other surface of the two surfaces included in the detection coil substrate 140. The upper surface 141 is a surface arranged closer to the foreign matter detection region than the lower surface 142 in the first direction. The upper surface 141 is an example of the first surface. The lower surface 142 is an example of the second surface.

The foreign matter detection region is a region that extends in the direction opposite to the direction in which the power transmission coil unit 210 is located when viewed from the detection coil unit 110. That is, the upper surface 141 is a surface away from the power transmission coil unit 210 than the lower surface 142 in the first direction. According to such a configuration, the surface on which the sensor coil 120 is arranged can be made into one surface, and the configuration of the detection coil unit 110 can be simplified.

Note that FIG. 6 shows a cross-sectional view of the power transmission coil unit 210 in addition to the cross-sectional view of the detection coil unit 110 for easy understanding. The opening 212A in FIG. 6 is an opening of the power transmission coil 211. Further, the metal plate 213 shown in FIG. 6 is a plate-shaped member made of metal, which constitutes a part of the housing of the power transmission coil unit 210. The metal plate 213 plays a role of blocking the magnetic flux generated from the power transmission coil 211.

Next, the configuration of the detection unit 150 will be described with reference to FIG. 7. The detection unit 150 detects the foreign matter 10 existing in the foreign matter detection region based on the signals output from the plurality of sensor coils 120A and the plurality of sensor coils 120B. That is, both the sensor coil 120A and the sensor coil 120B are used for detecting the foreign matter 10. Therefore, the detection unit 150 is connected to each of the plurality of sensor coils 120A via wiring, and is connected to each of the plurality of sensor coils 120B via wiring.

The detection unit 150 is realized by, for example, a computer equipped with a CPU (Central Processing Unit), a memory, an A / D (Analog / Digital) conversion device, and an operation program. Functionally, the detection unit 150 includes a detection control unit 151, a selection unit 152, a drive unit 153, an output value acquisition unit 154, a storage unit 155, a result output unit 156, and a power transmission control unit 157. Be prepared.

The detection unit 150 selects any one of the 20 sensor coils 120 according to these components, turns on the switch 132 and the switch 133 of the selected sensor coil 120, and turns on the switch 132 of the selected sensor coil 120, and the sensor coil 120 that is not selected. The switch 132 and the switch 133 are turned off to detect the presence or absence of foreign matter 10 in the vicinity of the selected sensor coil 120. The detection unit 150 sequentially detects the presence or absence of such foreign matter in all of the 20 sensor coils 120, and outputs the detection result.

The detection control unit 151 controls each component included in the detection unit 150, detects the foreign matter 10, outputs the detection result, and the like. The selection unit 152 selects any of the 20 sensor coils 120 according to the control by the detection control unit 151, and controls the switch 132 and the switch 133 included in the selected sensor coil 120 to be in the ON state. After the selection and on control by the selection unit 152 is executed, the drive unit 153 drives the pulse generation unit 160 according to the control by the detection control unit 151 to generate a single pulse voltage in the pulse generation unit 160. .. This pulsed voltage is applied to the resonant circuit formed in the selected sensor coil 120 via the external connector 145. Further, the voltage between both ends of the resonance circuit is guided to the output value acquisition unit 154 via the external connector 145.

The output value acquisition unit 154 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 control unit 151. The value of the output value acquired by the output value acquisition unit 154 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 storage unit 155 stores various data related to the foreign matter detection process executed by the foreign matter detection device 100. For example, the storage unit 155 stores an output value, a reference value, a difference value, and a threshold value. The output value is an output value acquired by the output value acquisition unit 154. The reference value is a reference value of the output value. That is, the reference value is an output value acquired when the foreign matter 10 does not exist in the vicinity of the sensor coil 120. The reference value is acquired in advance by an experiment, a simulation, or the like, and is stored in the storage unit 155.

The difference value is the value of the difference between the reference value, which is the output value acquired when there is no foreign matter 10, and the currently acquired output value. That is, the difference value is the amount of change from the output value acquired when there is no foreign matter 10. A small difference value means that there is a high possibility that the foreign matter 10 does not exist, and a large difference value means that there is a high possibility that the foreign matter 10 exists. The threshold value is a threshold value for discriminating the difference value. The threshold value is determined in advance in consideration of, for example, the predicted magnitude of noise, the degree of change in the output value depending on the presence or absence of the foreign matter 10, and is stored in the storage unit 155.

The detection control unit 151 determines the presence or absence of the foreign matter 10 based on the comparison result between the comparison target value and the threshold value based on the output value of the sensor coil 120. The comparison target value is a value of the target to be compared with the threshold value, and specifically, is a difference value between the output value and the reference value or a value based on this difference value. In the present embodiment, the comparison target value is a difference value between the output value and the reference value. For example, when it is determined that the comparison target value exceeds the threshold value for any one of the 20 sensor coils 120, the detection control unit 151 outputs the detection result that the foreign matter 10 is present.

The result output unit 156 outputs the detection result by the detection control unit 151 according to the control by the detection control unit 151. For example, when the detection control unit 151 determines that the foreign matter 10 is present, the result output unit 156 instructs the notification unit 170 to notify the presence of the foreign matter 10. When the notification unit 170 receives the notification from the detection control unit 151, the notification unit 170 transmits information indicating that the foreign matter has been detected to the terminal device 600 possessed by the user. On the other hand, the terminal device 600 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 157 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 control unit 151. When the detection control unit 151 determines that the foreign matter 10 is present, the power transmission control unit 157 instructs the power supply device 220 to stop power transmission.

In the present embodiment, the sensor coil 120A having the opening 123A is arranged at a position where at least a part of the opening 123A overlaps with the opening 123B larger than the opening 123A included in the sensor coil 120B. According to the present embodiment, both the near foreign matter 10 and the distant foreign matter 10 are detected, and the foreign matter 10 is detected in a wide range without omission.

Further, in the present embodiment, the number of sensor coils 120A is larger than the number of sensor coils 120B. Further, in the present embodiment, each of the plurality of sensor coils 120B has an opening 123B having an opening 123A of each of at least two sensor coils 120A among the plurality of sensor coils 120A when viewed from the first direction. It is placed in an overlapping position. According to this embodiment, the foreign matter 10 is efficiently detected in a wide range without leakage with a small number of sensor coils 120.

Further, in the present embodiment, the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged on the same surface. According to the present embodiment, the surface on which the sensor coil 120 is arranged can be made into one surface, and the configuration of the detection coil unit 110 can be simplified.

(Embodiment 2)
In the first embodiment, an example in which the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged on the same surface has been described. In this embodiment, an example in which the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged on different surfaces will be described. The description of the same configuration and processing as in the first embodiment will be omitted or simplified.

FIG. 8 shows a plan view of the detection coil unit 110A according to the present embodiment. FIG. 9 shows a cross-sectional view taken along the line BB in FIG. FIG. 10 shows an enlarged cross-sectional view showing a part of the cross-sectional view shown in FIG. For ease of understanding, FIG. 9 shows a cross-sectional view of the power transmission coil unit 210 in addition to the cross-sectional view of the detection coil unit 110A.

As shown in FIG. 8, the detection coil unit 110A includes 16 sensor coils 120A and 4 sensor coils 120B. Then, as shown in FIGS. 8 and 9, 16 sensor coils 120A are arranged on the upper surface 141 of the detection coil board 140, and 4 sensor coils 120B are arranged on the lower surface 142 of the detection coil board 140. To. The lower surface 142 is a surface whose position in the first direction is different from that of the upper surface 141. In FIG. 8, the sensor coil 120A arranged on the upper surface 141 is shown by a solid line, and the sensor coil 120B arranged on the lower surface 142 is shown by a broken line.

Here, when the surface on which the sensor coil 120A is arranged and the surface on which the sensor coil 120B is arranged are different, the degree of freedom in the arrangement of the sensor coil 120A and the sensor coil 120B is high. Therefore, for example, the coil conductor 121A of the sensor coil 120A can be arranged at a position overlapping with the coil conductor 121B of the sensor coil 120B when viewed from the first direction. In the present embodiment, the outer portion of the coil conductor 121A as seen from the shaft 124B and a part of the coil conductor 121B overlap when viewed from the first direction.

Further, the upper surface 141 is arranged closer to the foreign matter detection region than the lower surface 142 in the first direction. That is, in the present embodiment, the sensor coil 120A that easily detects the foreign matter 10 in the vicinity is arranged closer to the foreign matter 10 than the sensor coil 120B that easily detects the foreign matter 10 in the distance. Therefore, according to the present embodiment, it is easy to detect the nearby foreign matter 10.

Further, in the present embodiment, the plurality of sensor coils 120A are portions in which a part of the coil conductor 121A of the sensor coil 120A or a part of the opening 123A is adjacent to each other of the plurality of sensor coils 120B when viewed from the first direction. It is arranged at a position overlapping with the coil conductor 121B of. In the example shown in FIG. 10, the sensor coil 120AA is a portion of the sensor coil 120AA in which a part of the coil conductor 121AA or a part of the opening 123AA is adjacent to each other of the plurality of sensor coils 120BA and 120BB when viewed from the first direction. It is arranged at a position overlapping with the coil conductors 121BA and 121BB.

In other words, basically, in FIG. 10, the area 126A or the area 127A is arranged at a position where the area 126A or the area 127A overlaps with the area 128B when viewed from the first direction. The region 126A is a region including a region overlapping the two coil conductors 121AA that circulate and a region between the two coil conductors 121AA when viewed from the first direction. The region 127A is a region overlapping the opening 123AA when viewed from the first direction. The region 128A is a region that overlaps the outer coil conductor 121BA of the two orbiting coil conductors 121BA and a region that overlaps the outer coil conductor 121BB of the two orbiting coil conductors 121BB when viewed from the first direction. , A region including the region between the outer coil conductor 121BA and the outer coil conductor 121BB.

Note that the sensor coil 120A is a general term for the sensor coil 120AA and the sensor coil 120AB. The sensor coil 120B is a general term for the sensor coil 120BA and the sensor coil 120BB. The coil conductor 121A is a general term for the coil conductor 121AA and the coil conductor 121AB. The coil conductor 121B is a general term for the coil conductor 121BA and the coil conductor 121BB. The opening 123A is a general term for the opening 123AA and the opening 123AB. According to such a configuration, the sensor coil 120A can detect the foreign matter 10 in the region where the sensor coil 120B is difficult to detect. The region where the sensor coil 120B is difficult to detect is a region which overlaps with a portion of the plurality of sensor coils 120B adjacent to each other when viewed from the first direction.

Further, in the present embodiment, each of the plurality of sensor coils 120A is arranged at a position where the opening 123A is arranged inside the coil conductor 121B of the sensor coil 120B when viewed from the first direction. For example, in FIG. 10, the sensor coil 120AA is arranged at a position where the opening 123AA is arranged inside the inner coil conductor 121BA of the coil conductor 121BA for two rounds of the sensor coil 120BA when viewed from the first direction. Will be done.

Further, the sensor coil 120AB is arranged at a position where the opening 123AB is arranged inside the inner coil conductor 121BB of the coil conductors 121BB for two rounds of the sensor coil 120BB when viewed from the first direction. According to such a configuration, the influence of the coil conductor 121B is small when the foreign matter 10 is detected by the sensor coil 120A. Therefore, according to this configuration, the foreign matter 10 is detected with high accuracy by the sensor coil 120A.

Further, in the present embodiment, as shown in FIG. 8, the detection coil substrate 140 has a through hole 143 penetrating the upper surface 141 and the lower surface 142 at a position facing each opening 123A of the plurality of sensor coils 120A. To prepare for. The through hole 143 is provided at a position avoiding the position where the coil conductor 121A of the sensor coil 120A is arranged. The through hole 143 is a hole through which the rib 250 included in the power transmission device 200 passes.

The rib 250 is a support column for appropriately fixing the detection coil unit 110 to the power transmission device 200. That is, the through hole 143 and the rib 250 fix the detection coil unit 110 at an appropriate position in the power transmission device 200. Further, when the detection coil unit 110 is fixed to the power transmission device 200 by the through hole 143 and the rib 250, the durability of the detection coil unit 110 is enhanced. For example, when the electric vehicle 700 rides on the detection coil unit 110, the load bearing capacity of the detection coil unit 110 is improved. As described above, the through hole 143 and the rib 250 facilitate positioning and can be expected to improve durability.

In this embodiment, the sensor coil 120A is arranged on the upper surface 141, and the sensor coil 120B is arranged on the lower surface 142. According to this embodiment, the degree of freedom in the arrangement of the sensor coil 120A and the sensor coil 120B is high. Further, in the present embodiment, the upper surface 141 is arranged closer to the foreign matter detection region than the lower surface 142. According to this embodiment, it is easy to detect a nearby foreign matter 10.

Further, in the present embodiment, the sensor coil 120A is arranged at a position where a part of the coil conductor 121A of the sensor coil 120A or a part of the opening 123A overlaps the coil conductor 121B of the portions of the plurality of sensor coils 120B adjacent to each other. Will be done. According to this embodiment, the sensor coil 120A can detect the foreign matter 10 in the region where the sensor coil 120B is difficult to detect.

Further, in the present embodiment, each of the plurality of sensor coils 120A is arranged at a position where the opening 123A is arranged inside the coil conductor 121B of the sensor coil 120B when viewed from the first direction. According to this embodiment, the foreign matter 10 is detected with high accuracy by the sensor coil 120A.

Further, in the present embodiment, the detection coil substrate 140 is provided with a through hole 143 penetrating the upper surface 141 and the lower surface 142 at a position facing each opening 123A of the plurality of sensor coils 120A. According to this embodiment, the positioning of the detection coil board 140 becomes easy, and the durability of the detection coil board 140 can be expected to be improved.

(Embodiment 3)
In the first and second embodiments, an example in which a plurality of sensor coils 120A and a plurality of sensor coils 120B are arranged over the entire surface of the detection coil substrate 140 has been described. In the present embodiment, a plurality of sensor coils 120A and a plurality of sensor coils 120B are arranged in a part of the detection coil board 140, and the sensor coils 120C are arranged in another area of the detection coil board 140. explain. The description of the same configurations and processes as those of the first and second embodiments will be omitted or simplified.

FIG. 11 is a plan view of the detection coil unit 110B according to the present embodiment. As shown in FIG. 11, the detection coil unit 110B includes 32 sensor coils 120A and 8 sensor coils 120B, and the sensor coils 120C do not overlap the 32 sensor coils 120A and the 8 sensor coils 120B. To prepare for. In this embodiment, an example in which the number of sensor coils 120C is one will be described, but the number of sensor coils 120C may be two or more.

The sensor coil 120C has an opening 123C. The detection unit 150 detects the foreign matter 10 based on the signals output from the 32 sensor coils 120A, the 8 sensor coils 120B, and the 1 sensor coil 120C. The sensor coil 120C is an example of the third sensor coil. The opening 123C is an example of the third opening.

The 32 sensor coils 120A are arranged on the upper surface 141 of the detection coil substrate 140. The eight sensor coils 120B and the sensor coils 120C are arranged on the lower surface 142 of the detection coil substrate 140. In FIG. 11, the sensor coil 120A arranged on the upper surface 141 is shown by a solid line, and the sensor coil 120B and the sensor coil 120C arranged on the lower surface 142 are shown by a broken line. In FIG. 11, the sensor coil 120A, the sensor coil 120B, and the sensor coil 120C are simplified and shown by a double line representing a loop for two rounds.

When viewed from the first direction, the opening 123C of the sensor coil 120C is larger than the opening 123B of the sensor coil 120B. Therefore, the sensor coil 120C can detect the distant foreign matter 10 to the same extent or more as compared with the sensor coil 120B. In this embodiment, the opening 123C has the same size as the opening 123B.

The sensor coil 120C is arranged in the inner region of the annular first region in which the 32 sensor coils 120A and the 8 sensor coils 120B are arranged when viewed from the first direction. In the present embodiment, the first region is basically a region that overlaps with the conducting wire constituting the power transmission coil 211 when viewed from the first direction. Further, in the present embodiment, the second region, which is the inner region of the first region, is basically a region that overlaps with the opening portion of the power transmission coil 211 when viewed from the first direction.

Here, when viewed from the first direction, the region overlapping the conducting wire constituting the power transmission coil 211 is basically a region where the density of the magnetic flux generated from the power transmission coil 211 is high. Therefore, the region that overlaps with the first region when viewed from the first direction is a region that is easily affected by the magnetic flux generated from the power transmission coil 211, and is a region that is extremely unfavorable if the foreign matter 10 is present. If the foreign matter 10 is present in a region susceptible to the magnetic flux, there is a high possibility that the foreign matter 10 will be heated rapidly and the foreign matter 10 will rapidly reach a high temperature. On the other hand, even if the foreign matter 10 is present in a region that is not easily affected by the magnetic flux, the foreign matter 10 is not heated so much and the possibility that the foreign matter 10 becomes high is low.

Therefore, the sensor coil 120A and the sensor coil 120B are arranged in the first region of the detection coil substrate 140, and the foreign matter 10 arranged in the region overlapping the first region when viewed from the first direction is detected without omission. That is, the foreign matter 10 arranged near the foreign matter detecting device 100 in the region overlapping the first region when viewed from the first direction is quickly detected by the sensor coil 120A. Further, the foreign matter 10 arranged far away from the foreign matter detecting device 100 in the region overlapping the first region when viewed from the first direction is quickly detected by the sensor coil 120B.

On the other hand, when viewed from the first direction, the region overlapping the opening portion of the power transmission coil 211 is basically a region where the density of the magnetic flux generated from the power transmission coil 211 is low. Therefore, the region that overlaps with the second region when viewed from the first direction is a region that is not easily affected by the magnetic flux generated from the power transmission coil 211, and is a region that is unlikely to cause a problem even if the foreign matter 10 is present. Therefore, the sensor coil 120C is arranged in the second region of the detection coil substrate 140, and the foreign matter 10 arranged in the region overlapping the second region when viewed from the first direction is appropriately detected by the sensor coil 120C.

In the present embodiment, at least one sensor coil 120C that does not overlap the plurality of sensor coils 120A and the plurality of sensor coils 120B is provided. Therefore, according to the present embodiment, it is possible to realize appropriate foreign matter detection according to the necessity of foreign matter detection for each region.

Further, in the present embodiment, the opening 123C has a size larger than that of the opening 123B when viewed from the first direction. Therefore, according to the present embodiment, the foreign matter 10 arranged in the region where the foreign matter detection in each region is highly necessary is reliably detected, and the foreign matter 10 arranged in the region where the foreign matter detection in each region is low is low. Is also properly detected.

Further, in the present embodiment, the sensor coil 120C is arranged in a region inside the annular first region in which the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged when viewed from the first direction. .. Therefore, according to the present embodiment, the foreign matter 10 arranged in the region susceptible to the magnetic flux is reliably detected, and the foreign matter 10 arranged in the region less susceptible to the magnetic flux is also appropriately detected.

(Embodiment 4)
In the third embodiment, a plurality of sensor coils 120A and a plurality of sensor coils 120B are arranged in a part of the detection coil board 140, and the sensor coils 120C are arranged in another area of the detection coil board 140. explained. In the present embodiment, a plurality of sensor coils 120A and a plurality of sensor coils 120B are arranged in a part of the detection coil board 140, and the sensor coils 120C are arranged in other areas of the detection coil board 140, and the detection coils are arranged. An example in which the sensor coil 120D is arranged in still another region of the substrate 140 will be described. The description of the same configuration and processing as those of the first to third embodiments will be omitted or simplified.

FIG. 12 is a plan view of the detection coil unit 110C according to the present embodiment. As shown in FIG. 12, the detection coil unit 110C includes 32 sensor coils 120A, 8 sensor coils 120B, and sensor coils 120C, and overlaps with 32 sensor coils 120A and 8 sensor coils 120B. It is further provided with 16 sensor coils 120D that do not become.

The sensor coil 120D has an opening 123D. The detection unit 150 detects the foreign matter 10 based on the signals output from the 32 sensor coils 120A, the 8 sensor coils 120B, the 1 sensor coil 120C, and the 16 sensor coils 120D. The sensor coil 120D is an example of the fourth sensor coil. The opening 123D is an example of the fourth opening.

The 32 sensor coils 120A are arranged on the upper surface 141 of the detection coil substrate 140. The eight sensor coils 120B, the sensor coils 120C, and the 16 sensor coils 120D are arranged on the lower surface 142 of the detection coil substrate 140. In FIG. 12, the sensor coil 120A arranged on the upper surface 141 is shown by a solid line, and the sensor coil 120B, the sensor coil 120C, and the sensor coil 120D arranged on the lower surface 142 are shown by a broken line. In FIG. 12, the sensor coil 120A, the sensor coil 120B, the sensor coil 120C, and the sensor coil 120D are simplified by a double line representing a loop for two rounds.

When viewed from the first direction, the opening 123D of the sensor coil 120D is larger than the opening 123B of the sensor coil 120B. Therefore, the sensor coil 120D can detect the distant foreign matter 10 to the same extent or more as compared with the sensor coil 120B. In this embodiment, the opening 123D has the same size as the opening 123B.

The sensor coil 120D is arranged in a region outside the annular first region in which the 32 sensor coils 120A and the eight sensor coils 120B are arranged when viewed from the first direction. In the present embodiment, the third region, which is the region outside the first region, is basically a region outside the power transmission coil 211 when viewed from the first direction.

Here, when viewed from the first direction, the region outside the power transmission coil 211 is basically a region where the density of the magnetic flux generated from the power transmission coil 211 is low. Therefore, the region that overlaps with the third region when viewed from the first direction is a region that is not easily affected by the magnetic flux generated from the power transmission coil 211, and is a region that is unlikely to cause a problem even if the foreign matter 10 is present. Therefore, the sensor coil 120D is arranged in the third region of the detection coil substrate 140, and the foreign matter 10 arranged in the region overlapping the third region when viewed from the first direction is appropriately detected by the sensor coil 120D.

In the present embodiment, in addition to the plurality of sensor coils 120A, the plurality of sensor coils 120B, and at least one sensor coil 120C, the plurality of sensor coils 120A and the plurality of sensor coils 120D that do not overlap with the plurality of sensor coils 120A are provided. It will be provided. Therefore, according to the present embodiment, it is possible to realize appropriate foreign matter detection according to the necessity of foreign matter detection for each region.

Further, in the present embodiment, the opening 123D is larger than the opening 123B when viewed from the first direction. Therefore, according to the present embodiment, the foreign matter 10 arranged in the region where the foreign matter detection in each region is highly necessary is reliably detected, and the foreign matter 10 arranged in the region where the foreign matter detection in each region is low is low. Is also properly detected.

Further, in the present embodiment, the sensor coil 120D is arranged in a region outside the annular first region in which the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged when viewed from the first direction. .. Therefore, according to the present embodiment, the foreign matter 10 arranged in the region susceptible to the magnetic flux is reliably detected, and the foreign matter 10 arranged in the region less susceptible to the magnetic flux is also appropriately detected.

(Embodiment 5)
In the second embodiment, an example in which the sensor coil 120A is arranged at a position where the opening 123A is arranged inside the coil conductor 121B of the sensor coil 120B when viewed from the first direction has been described. In the present embodiment, an example will be described in which the sensor coil 120A is arranged at a position where a part of the opening 123A overlaps with the opening 123B of the sensor coil 120B when viewed from the first direction. The description of the same configuration and processing as those of the first and fourth embodiments will be omitted or simplified.

In the present embodiment, as shown in FIG. 13, the sensor coil 120A is arranged at a position where the opening 123A straddles the coil conductor 121B of the sensor coil 120B when viewed from the first direction. Therefore, when viewed from the first direction, a part of the opening 123A overlaps a part of the opening 123B, and the other part of the opening 123A overlaps the outer region of the sensor coil 120B. In FIG. 13, three sensor coils 120A out of the four sensor coils 120A are not shown.

In the present embodiment, the sensor coil 120A is arranged at a position where a part of the opening 123A overlaps with the opening 123B of the sensor coil 120B when viewed from the first direction. Therefore, according to the present embodiment, the foreign matter 10 arranged in the region overlapping the opening 123A and the opening 123B when viewed from the first direction is irrespective of the distance from the foreign matter detecting device 100 to the foreign matter 10. Properly detected.

(Embodiment 6)
In the fourth embodiment, the plurality of sensor coils 120A and the plurality of sensor coils 120B are arranged in a region overlapping the conductors constituting the power transmission coil 211 when viewed from the first direction, and the power transmission coil 211 has the power transmission coil 211 when viewed from the first direction. An example in which the sensor coil 120C is arranged in the region overlapping the opening portion and the plurality of sensor coils 120D are arranged in the region outside the power transmission coil 211 when viewed from the first direction has been described. In this embodiment, an example in which a plurality of sensor coils 120A and a plurality of sensor coils 120B are arranged in a region outside the power transmission coil 211 when viewed from the first direction will be described. The description of the same configuration and processing as in the first to fifth embodiments will be omitted or simplified.

FIG. 14 is a plan view of the detection coil unit 110D according to the present embodiment. As shown in FIG. 14, the detection coil unit 110D includes 96 sensor coils 120A, 24 sensor coils 120B, and sensor coils 120C. The detection unit 150 detects the foreign matter 10 based on the signals output from the 96 sensor coils 120A, the 24 sensor coils 120B, and the sensor coils 120C.

The 96 sensor coils 120A are arranged on the upper surface 141 of the detection coil substrate 140. The 24 sensor coils 120B and the sensor coils 120C are arranged on the lower surface 142 of the detection coil substrate 140. In FIG. 14, the sensor coil 120A arranged on the upper surface 141 is shown by a solid line, and the sensor coil 120B and the sensor coil 120C arranged on the lower surface 142 are shown by a broken line. In FIG. 14, the sensor coil 120A, the sensor coil 120B, and the sensor coil 120C are simplified and shown by a double line representing a loop for two rounds.

In the present embodiment, as shown in FIG. 14, a plurality of sensor coils 120A and a plurality of sensor coils 120B are provided in a region overlapping the conductors constituting the power transmission coil 211 and a region outside the power transmission coil 211 when viewed from the first direction. And are arranged, and the sensor coil 120C is arranged in the region overlapping the opening portion of the transmission coil 211 when viewed from the first direction.

Here, in the region outside the power transmission coil 211 when viewed from the first direction, the density of the magnetic flux generated from the power transmission coil 211 may be high to some extent. In this case, the region outside the power transmission coil 211 when viewed from the first direction is a region affected to some extent by the magnetic flux generated from the power transmission coil 211, and is a region unfavorable when foreign matter 10 is present. Therefore, in the present embodiment, there are a plurality of sensor coils 120A and a plurality of sensor coils 120A in the region outside the power transmission coil 211 when viewed from the first direction, as in the region overlapping the conductors constituting the power transmission coil 211 when viewed from the first direction. The sensor coil 120B of the above is arranged.

In the present embodiment, a plurality of sensor coils 120A and a plurality of sensor coils 120B are arranged in a region overlapping the conductors constituting the power transmission coil 211 and a region outside the power transmission coil 211 when viewed from the first direction. Therefore, according to the present embodiment, the foreign matter 10 arranged in the region where the foreign matter detection in each region is highly necessary is reliably detected, and the foreign matter 10 arranged in the region where the foreign matter detection in each region is low is low. Is also properly detected.

(Embodiment 7)
In the first to sixth embodiments, 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 101 will be described. The description of the same configuration and processing as in the first to sixth embodiments will be omitted or simplified.

As shown in FIG. 15, the foreign matter detection device 101 includes a detection coil unit 110, a detection unit 150, a pulse generation unit 160, a notification unit 170, and a communication unit 180.

As shown in FIG. 15, 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 detection unit 150 determines whether or not a foreign substance is present in the detection target region based on the output value of the sensor coil 120 excited by the application of the pulsed voltage. The detection unit 150 controls the communication unit 180 in addition to the pulse generation unit 160 and the notification unit 170.

The pulse generating unit 160 generates a pulsed voltage for detecting foreign matter, and selects and applies the sensor coil 120. When the detection unit 150 detects a foreign substance, the notification unit 170 notifies the user that the foreign substance has been detected. When the detection unit 150 determines that there is a foreign substance, the communication unit 180 transmits a signal instructing the power transmission device 200 to stop power transmission to the power transmission device 300. On the other hand, the power supply device 220 included in the power transmission device 200 stops supplying power to the power transmission coil unit 210 in response to receiving this signal, and stops power transmission.

In the present embodiment, the power receiving device 300 is provided with the foreign matter detecting device 101, and when the foreign matter 10 is detected, a signal instructing the power transmission device 200 to stop power transmission is transmitted. Therefore, according to the present embodiment, even when the foreign matter detecting device 101 is provided in the power receiving device 300 from various viewpoints, if the foreign matter 10 is detected, the power transmission can be stopped for safety.

(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 the sensor coil 120 is arranged on one surface of the detection coil board 140 will be described, and in the second embodiment, the sensor coil 120 is arranged on both surfaces of the detection coil board 140. An example was explained. The surface on which the sensor coil 120 is arranged is not limited to these examples. For example, the sensor coil 120 may be arranged on a plane orthogonal to the detection coil board 140 inside the detection coil board 140. Further, the sensor coil 120 may be arranged on three or more surfaces. Further, the sensor coil 120 may be arranged on a surface provided outside the detection coil substrate 140.

In the first to sixth embodiments, an example in which the sensor coil 120 has a loop for two rounds has been described. The sensor coil 120 may have one loop or three or more loops. Further, in the first to sixth embodiments, an example in which the sensor coil 120 is composed of a conductor pattern mounted on the detection coil substrate 140 has been described. The sensor coil 120 may be configured by winding a conducting wire.

In the first to sixth embodiments, an example in which four sensor coils 120A are provided for one sensor coil 120B has been described. The relationship between the number of sensor coils 120B and the number of sensor coils 120A is not limited to this example. Further, the number of the sensor coils 120 arranged in the X-axis direction and the number of the sensor coils 120 arranged in the Y-axis direction are not limited to the examples described in the first to sixth embodiments.

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, 101 Foreign matter detection device 110, 110A, 110B, 110C, 110D Detection coil unit 120, 120A, 120B, 120C, 120D, 120AA, 120AB, 120BA, 120BB Sensor coil 121A, 121B Coil conductor 123, 123A, 123B, 123AA, 123AB, 123BA, 123BB, 212A Opening 124A, 124B Axis 125A, 125B, 126A, 127A, 128B Region 131 Capsule 132, 133 Switch 140 Detection coil board 141 Top surface 142 Bottom surface 143 Through hole 145 External connection connector 150 Detection unit 151 Detection control unit 152 Selection unit 153 Drive unit 154 Output value acquisition unit 155 Storage unit 156 Result output unit 157 Transmission control unit 160 Pulse generation unit 170 Notification unit 180 Communication unit 200 Transmission device 210 Transmission coil unit 211 Transmission coil 212 Magnetic plate 213 Metal plate 220 Power supply device 250 Rib 300 Power receiving device 310 Power receiving coil unit 311 Power receiving coil 312 Magnetic plate 320 Rectification circuit 400 Commercial power supply 500 Storage battery 600 Terminal device 700 Electric vehicle 1000 Power transmission system

Claims (19)

1. A first sensor coil with a first opening and
   A second sensor coil having a second opening larger than the first opening when viewed from the first direction in which the winding shaft of the first sensor coil extends.
   A detection unit that detects foreign matter existing in the foreign matter detection region based on the signals output from the first sensor coil and the second sensor coil is provided.
   The first sensor coil is arranged at a position where at least a part of the first opening is overlapped with the second opening when viewed from the first direction.
   Foreign matter detector.
2. With the plurality of the first sensor coils
   The second sensor coil is provided with a plurality of the second sensor coils.
   The number of the plurality of first sensor coils is larger than the number of the plurality of second sensor coils.
   The foreign matter detection device according to claim 1.
3. Each of the plurality of second sensor coils has the first opening in which the second opening is possessed by each of at least two of the first sensor coils among the plurality of first sensor coils when viewed from the first direction. It is placed at a position that overlaps with the part,
   The foreign matter detection device according to claim 2.
4. The plurality of first sensor coils and the plurality of second sensor coils are arranged on the same surface.
   The foreign matter detection device according to claim 2 or 3.
5. The plurality of first sensor coils are arranged on the first surface, and the plurality of first sensor coils are arranged on the first surface.
   The plurality of second sensor coils are arranged on a second surface whose position in the first direction is different from that of the first surface.
   The foreign matter detection device according to claim 2 or 3.
6. When the plurality of first sensor coils are viewed from the first direction, a part of the coil conductor of the first sensor coil or a part of the first opening is a portion of the plurality of second sensor coils adjacent to each other. It is located at the position where it overlaps with the coil conductor of
   The foreign matter detection device according to claim 5.
7. The first surface is arranged closer to the foreign matter detection region than the second surface in the first direction.
   The foreign matter detection device according to claim 5 or 6.
8. Each of the plurality of first sensor coils is arranged at a position where the first opening is arranged inside the coil conductor of the second sensor coil when viewed from the first direction.
   The foreign matter detection device according to any one of claims 5 to 7.
9. A substrate having the first surface and the second surface is further provided.
   The substrate has a through hole penetrating between the first surface and the second surface at a position facing the first opening of each of the plurality of first sensor coils.
   The foreign matter detection device according to any one of claims 5 to 8.
10. Further comprising at least one third sensor coil that does not overlap the plurality of first sensor coils and the plurality of second sensor coils when viewed from the first direction.
    The at least one third sensor coil has a third opening.
    The detection unit detects the foreign matter based on the signals output from the plurality of first sensor coils, the plurality of second sensor coils, and the at least one third sensor coil.
    The foreign matter detection device according to any one of claims 2 to 9.
11. When viewed from the first direction, the third opening is larger than the second opening.
    The foreign matter detection device according to claim 10.
12. The at least one third sensor coil is located in a region inside an annular first region in which the plurality of first sensor coils and the plurality of second sensor coils are arranged when viewed from the first direction. Have been placed,
    The foreign matter detecting device according to claim 10 or 11.
13. Further, a plurality of fourth sensor coils that do not overlap the plurality of first sensor coils and the plurality of second sensor coils when viewed from the first direction are further provided.
    Each of the plurality of fourth sensor coils has a fourth opening.
    The detection unit is based on signals output from the plurality of first sensor coils, the plurality of second sensor coils, the at least one third sensor coil, and the plurality of fourth sensor coils. To detect,
    The foreign matter detection device according to claim 12.
14. When viewed from the first direction, the fourth opening is larger than the second opening.
    The foreign matter detection device according to claim 13.
15. The plurality of fourth sensor coils are arranged in a region outside the first region when viewed from the first direction.
    The foreign matter detection device according to claim 13 or 14.
16. A power transmission coil composed of wound conductors and
    The foreign matter detecting device according to any one of claims 1 to 15 is provided.
    Power transmission device.
17. A power receiving coil composed of wound conductors and
    The foreign matter detecting device according to any one of claims 1 to 15 is provided.
    Power receiving device.
18. The power transmission device according to claim 16 and
    A power receiving device that receives power from the power transmitting device, and the like.
    Power transmission system.
19. The power receiving device according to claim 17, and the power receiving device.
    A power transmission device for transmitting power to the power receiving device, and the like.
    Power transmission system.

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