Foreign object detection device and coil device

Abstract

In order to reduce a region in which foreign matter detection is difficult, the size of an additional detection coil disposed so as to overlap with the detection coil is reduced. A foreign matter detection device is provided with: a first detection coil having a plurality of first coils; a second detection coil having a plurality of second coils; and a control unit. The plurality of first coils are electrically connected in series in such a manner that the current flowing through adjacent first coils is reversed, and the second coils are electrically connected in series in such a manner that the current flowing through adjacent second coils is reversed. The wirings of the first coils are arranged in parallel and close to each other at a boundary portion between adjacent first coils. The control unit applies a voltage to each of the detection coils to determine the presence or absence of foreign matter. The second detection coil is disposed such that a region surrounded by the wiring of the second coil overlaps an end portion of the boundary portion of the first coil.

Description

Technical Field

[0001] The present disclosure relates to a coil device having a coil and a foreign object detection device having the coil device. Background Art

[0002] An example of a foreign object detection device having a coil is disclosed in Patent Document 1. The foreign object detection device disclosed in Patent Document 1 includes a sensor coil and a determination device for detecting a foreign object based on a voltage of the sensor coil. The sensor coil includes a plurality of first unit sensor coils in a first winding direction and a plurality of second unit sensor coils in a second winding direction opposite to the first winding direction.

[0003] In the foreign matter detection device disclosed in Patent Document 1, when there is no foreign matter on the sensor coil, the first unit sensor coil and the second unit sensor coil penetrated by the external magnetic flux generate electromotive forces of the same magnitude and opposite signs. The electromotive force generated in the first unit sensor coil and the electromotive force generated in the second unit sensor coil cancel each other out. Therefore, when there is no foreign matter, the electromotive force generated in the sensor coil is zero.

[0004] On the other hand, in the foreign matter detection device disclosed in Patent Document 1, when a foreign matter is present on the sensor coil, the magnetic flux from the outside penetrating each unit sensor coil is deviated. As a result, the electromotive force generated in the sensor coil is not zero. The determination device determines whether a foreign matter is present based on whether the electric power of the sensor coil is zero.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2016 / 031209 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The detection method of the foreign object detection device disclosed in Patent Document 1 is a separately excited method based on the electromotive force generated by the sensor coil by the magnetic flux from the outside to detect the presence of foreign objects. In the separately excited foreign object detection device, when there is a foreign object on the boundary line between the adjacent first unit sensor coil and the second unit sensor coil, the electromotive force is canceled out as in the case where there is no foreign object, and the electromotive force generated by the sensor coil may become zero. That is, in the separately excited foreign object detection device, the entire area of ​​the boundary line between the adjacent first unit sensor coil and the second unit sensor coil is an area where foreign objects are difficult to detect, that is, a low sensitivity area.

[0010] Patent document 1 discloses a foreign object detection device in which two sensor coils are arranged to overlap each other at positions offset from each other. In the foreign object detection device, even if a foreign object exists in a low-sensitivity area of ​​one sensor coil and foreign object detection cannot be performed, foreign object detection can be performed in the other sensor coil.

[0011] However, in the foreign object detection device of the separate excitation mode, as described above, the low sensitivity area covers the entire area of ​​the boundary line between the first unit sensor coil and the second unit sensor coil. Therefore, when the additional sensor coil overlaps with the low sensitivity area of ​​one sensor coil, the size of the additional sensor coil becomes larger. For example, when the foreign object detection device is applied to wireless power transmission, the amount of power supplied by the wireless power transmission may be reduced due to the presence of the sensor coil, so the size of the sensor coil is preferably as small as possible.

[0012] Therefore, an object of the present disclosure is to solve the above-mentioned problems and to provide a foreign object detection device capable of reducing the size of an additional detection coil arranged to overlap with one detection coil in order to reduce a low-sensitivity region where foreign objects are difficult to detect.

[0013] Means for solving problems

[0014] A foreign matter detection device according to one embodiment of the present disclosure includes:

[0015] A first detection coil having a plurality of first coils arranged in a plan view;

[0016] at least one second detection coil having a plurality of second coils arranged in a plan view; and

[0017] a control unit capable of applying a voltage to the first detection coil and the second detection coil,

[0018] In the first detection coil, a plurality of the first coils are electrically connected in series in the following manner: when a current in a first winding direction flows through one of two adjacent first coils, a current in a second winding direction opposite to the first winding direction flows through the other of the two adjacent first coils.

[0019] In the second detection coil, a plurality of the second coils are electrically connected in series in the following manner: when a current in the first winding direction flows through one of two adjacent second coils, a current in the second winding direction flows through the other of the two adjacent second coils.

[0020] In the first detection coil, at a boundary between two adjacent first coils, a wiring included in one of the two first coils and a wiring included in the other of the two first coils are arranged parallel to and close to each other.

[0021] The control unit determines whether there is a foreign object on the first detection coil by applying a voltage to the first detection coil, and determines whether there is a foreign object on the second detection coil by applying a voltage to the second detection coil.

[0022] The second detection coil is arranged so that a region surrounded by wiring of the second coil overlaps a portion of the boundary portion of the first coil including an end portion of the boundary portion of the first coil in a plan view.

[0023] Effects of the Invention

[0024] According to the present disclosure, it is possible to reduce the size of an additional detection coil that is arranged to overlap with one detection coil in order to reduce a low-sensitivity region where foreign matter is difficult to detect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 An example of a wireless power supply device according to the embodiment is schematically illustrated.

[0026] Figure 2 A plan view of a first detection coil according to the embodiment is shown as an example.

[0027] Figure 3 A plan view schematically illustrates a first detection coil according to the embodiment.

[0028] Figure 4 A plan view schematically illustrates a second detection coil according to the embodiment.

[0029] Figure 5 A plan view schematically illustrates a first detection coil and a second detection coil according to an embodiment.

[0030] Figure 6 A block diagram schematically illustrates a control unit according to an embodiment.

[0031] Figure 7 A graph schematically illustrates a graph showing voltage versus time when a voltage is applied to the detection coil.

[0032] Figure 8 A flowchart for explaining the procedure of foreign matter detection by the foreign matter detection device is shown as an example.

[0033] Fig. 9 A flowchart for explaining the procedure of determining the presence or absence of foreign matter by the foreign matter detection device is shown as an example.

[0034] Fig.10 A plan view schematically illustrates a first detection coil according to a modified example.

[0035] Fig.11 A plan view schematically illustrates a first detection coil according to a modified example.

[0036] Fig.12 A plan view schematically illustrates a first detection coil according to a modified example.

[0037] Fig.13 A plan view of a second detection coil according to a modified example is schematically illustrated.

[0038] Fig.14 A wireless power supply device according to a modified example is schematically illustrated.

[0039] Fig.15 A wireless power supply device according to a modified example is schematically illustrated.

[0040] Fig.16 A wireless power supply device according to a modified example is schematically illustrated.

[0041] Fig.17 A wireless power supply device according to a modified example is schematically illustrated.

[0042] Fig.18 A wireless power supply device according to a modified example is schematically illustrated.

[0043] Fig.19 A plan view schematically illustrates a first detection coil and a second detection coil showing a modified example. DETAILED DESCRIPTION

[0044] Figure 1 An example of a wireless power supply device according to the embodiment is schematically illustrated. Figure 1 The foreign object detection device 10 shown is applied to, for example, the wireless power supply device 1. The foreign object detection device 10 determines whether a foreign object is mixed in the wireless power supply device 1 when the wireless power supply device 1 is performing wireless power supply.

[0045] like Figure 1 As shown, the wireless power supply device 1 includes a transmission coil 2 , a transmission-side cover 3 , a transmission control unit 4 , a reception coil 5 , a reception-side cover 6 , a reception control unit 7 , and a foreign object detection device 10 .

[0046] The transmitting coil 2 has, for example, a wiring pattern formed on the surface or inside of the substrate. The wiring pattern is an example of wiring. The wiring pattern is made of a conductive material such as copper. The wiring pattern is formed in a spiral shape, a helical shape, etc. In addition, the structure of the transmitting coil 2 is not limited to the wiring pattern formed on the substrate. For example, the transmitting coil 2 may also be composed of an electric wire formed in a spiral shape, a helical shape, etc. In this case, the electric wire is an example of wiring.

[0047] The transmission side cover 3 is a box-shaped member. The transmission coil 2 is arranged inside the transmission side cover 3. The material of the transmission side cover 3 is arbitrary, for example, resin. Figure 1 In the embodiment, the lower part of the transmission side cover 3 is open, but the structure of the transmission side cover 3 is not limited thereto. For example, the side of the transmission side cover 3 may be open, or the transmission side cover 3 may not be open.

[0048] The transmission control unit 4 controls the transmission of wireless power transfer (Wireless Power Transfer: WPT) from the transmitting coil 2 to the receiving coil 5. The transmission control unit 4 includes, for example, a microcontroller unit (MCU). When the MCU of the transmission control unit 4 receives a signal for starting power supply, it applies a voltage to the transmitting coil 2. The signal for starting power supply is transmitted to the transmission control unit 4 from, for example, a control unit (not shown) that controls the overall operation of the wireless power supply device 1, an interface unit (not shown) that mediates communication with an external device, etc. Current flows in the transmitting coil 2 to which the voltage is applied. As a result, a magnetic flux is generated in a manner that penetrates the transmitting coil 2. In the present embodiment, the transmission control unit 4 is electrically connected to the control unit 40 of the foreign object detection device 10.

[0049] The transmission coil 2 , the transmission-side cover 3 , and the transmission control unit 4 are components of a transmitter (Transmitter: Tx) of the wireless power supply device 1 .

[0050] The receiving coil 5 is arranged above the transmitting coil 2 so as to be opposite to the transmitting coil 2. The transmitting side cover 3, the receiving side cover 6, the first detection coil 20 and the second detection coil 30 of the foreign matter detection device 10 are provided between the receiving coil 5 and the transmitting coil 2. The receiving coil 5 is constructed in the same manner as the transmitting coil 2. The magnetic flux generated in the transmitting coil 2 passes through the receiving coil 5, thereby generating an electromotive force in the receiving coil 5. That is, power is transmitted from the transmitting coil 2 to the receiving coil 5.

[0051] The receiving-side cover 6 is configured similarly to the transmitting-side cover 3. The receiving coil 5 is arranged inside the receiving-side cover 6.

[0052] The reception control unit 7 controls the reception of wireless power transmission from the transmission coil 2 to the reception coil 5. The reception control unit 7 includes, for example, a microcontroller. The control of the reception coil 5 performed by the reception control unit 7 is, for example, control of the output voltage. The output voltage is adjusted (controlled) to an appropriate value according to the device or battery connected to the wireless power supply device 1.

[0053] The receiving coil 5 , the receiving-side cover 6 , and the receiving control unit 7 are components of a receiver (Receiver: Rx) of the wireless power supply device 1 .

[0054] The foreign object detection device 10 performs foreign object detection (FOD). In the present embodiment, the foreign object detection device 10 determines whether a foreign object 50 including metal or the like is mixed between the transmitting coil 2 and the receiving coil 5 of the wireless power supply device 1. When a foreign object 50 is mixed between the transmitting coil 2 and the receiving coil 5 while the wireless power supply device 1 is performing wireless power supply, the foreign object 50 may generate heat. When the foreign object detection device 10 determines that there is a foreign object 50, it sends a signal to the transmission control unit 4 to stop applying voltage to the transmitting coil 2. The transmission control unit 4 that receives the signal stops applying voltage to the transmitting coil 2. In this way, the heating of the foreign object 50 can be reduced or prevented.

[0055] The foreign object detection device 10 includes a coil device 15 and a control unit 40. The coil device 15 includes a first detection coil 20 and a plurality of second detection coils 30. Figure 1 3 second detection coils 30 are shown in FIG. 1 , but in this embodiment, the foreign matter detection device 10 includes five second detection coils 30 (see Figure 5 ).

[0056] The first detection coil 20 and the plurality of second detection coils 30 are arranged inside the transmitting side cover 3. The first detection coil 20 and the plurality of second detection coils 30 are located above the transmitting coil 2 and face the transmitting coil 2 in the vertical direction 100. The first detection coil 20 and the plurality of second detection coils 30 are located below the receiving coil 5 and face the receiving coil 5 in the vertical direction 100 via the transmitting side cover 3 and the receiving side cover 6. Figure 1 In the embodiment, the first detection coil 20 is arranged above the second detection coil 30 , but the arrangement may be the opposite. That is, the second detection coil 30 may also be arranged above the first detection coil 20 .

[0057] Figure 2 A top view of a first detection coil according to an embodiment of the present invention is shown. Figure 2 As shown in FIG. 1 , the first detection coil 20 has four first coils 201, 202, 203, and 204. In addition, the first detection coil 20 is not limited to four first coils. Figure 2 In the embodiment, the four first coils 201 , 202 , 203 , and 204 have the same shape and the same size, but may have different shapes and sizes.

[0058] In a plan view from above, the four first coils 201, 202, 203, and 204 are arranged on a virtual plane intersecting the up-down direction 100. In the present embodiment, the four first coils 201, 202, 203, and 204 are arranged in two rows and two columns.

[0059] The first coil 201 is composed of wiring patterns 201A, 201B, and 201C. The first coil 202 is composed of wiring patterns 202A, 202B, and 202C. The first coil 203 is composed of wiring patterns 203A, 203B, and 203C. The first coil 204 is composed of wiring patterns 204A, 204B, and 204C.

[0060] The four first coils 201, 202, 203, and 204 are electrically connected in series in a manner that satisfies the following two conditions. The first condition is that at the boundary between two adjacent first coils, the wiring pattern of one of the two first coils and the wiring pattern of the other of the two first coils are arranged parallel to and close to each other. The second condition is that when current flows in the first detection coil 20, the directions of the current flowing in the adjacent two first coils among the four first coils 201, 202, 203, and 204 are opposite to each other.

[0061] The first condition is described in detail below. Figure 2 The area indicated by the dotted line is the boundary 20A of the four first coils 201, 202, 203, and 204. At the boundary 20A between the first coil 201 and the first coil 202, the wiring pattern 201C of the first coil 201 and the wiring pattern 202C of the first coil 202 are arranged parallel to each other and close to each other. Also, at the boundary 20A between the first coil 201 and the first coil 203, the wiring pattern 201B of the first coil 201 and the wiring pattern 203B of the first coil 203 are arranged parallel to each other and close to each other. Also, at the boundary 20A between the first coil 202 and the first coil 204, the wiring pattern 202B of the first coil 202 and the wiring pattern 204B of the first coil 204 are arranged parallel to each other and close to each other. Furthermore, wiring pattern 203C of first coil 203 and wiring pattern 204C of first coil 204 are arranged parallel to and close to each other at boundary 20A between first coil 203 and first coil 204. It should be noted that parallel to each other includes not only completely parallel but also substantially parallel.

[0062] The second condition is described in detail below. Figure 2As shown by the arrows in , when a counterclockwise current I1 flows through the first coil 201, a clockwise current I2 flows through the first coil 202 adjacent to the first coil 201, and a clockwise current I3 flows through the first coil 203 adjacent to the first coil 201. Furthermore, when a counterclockwise current I1 flows through the first coil 201, a counterclockwise current I4 flows through the first coil 204 adjacent to the first coils 202 and 203 through which the clockwise currents I2 and I3 flow. The counterclockwise currents I1 and I4 are an example of currents in the first winding direction. The clockwise currents I2 and I3 are an example of currents in the second winding direction. In the above case, a current I1 flows from the first coil 201 to the first coil 204. Figure 2 The magnetic flux in the direction from the inner side to the front side of the paper is generated in the first coils 202 and 203. Figure 2 The magnetic flux from the front side of the paper to the inner side.

[0063] As described above, in the first detection coil 20, multiple first coils 201, 202, 203, and 204 are electrically connected in series in the following manner: when a current in a first winding direction flows through one of two adjacent first coils, a current in a second winding direction, which is opposite to the first winding direction, flows through the other of the two adjacent first coils.

[0064] As described above, when the four first coils 201, 202, 203, and 204 are electrically connected in series, the currents flowing in the adjacent wiring patterns when the current flows in the first detection coil 20 are in the same direction. Specifically, the direction of the current flowing in the wiring pattern 201B of the first coil 201 is the same as the direction of the current flowing in the wiring pattern 203B of the first coil 203. Furthermore, the direction of the current flowing in the wiring pattern 201C of the first coil 201 is the same as the direction of the current flowing in the wiring pattern 202C of the first coil 202. Furthermore, the direction of the current flowing in the wiring pattern 204B of the first coil 204 is the same as the direction of the current flowing in the wiring pattern 202B of the first coil 202. Furthermore, the direction of the current flowing in the wiring pattern 204C of the first coil 204 is the same as the direction of the current flowing in the wiring pattern 203C of the first coil 203.

[0065] Figure 2 The number of turns of each of the first coils 201 , 202 , 203 , and 204 shown is 2, but the number of turns may be other than 2. Furthermore, the number of turns of the first coils 201 , 202 , 203 , and 204 may be different from each other.

[0066] Figure 3 A plan view schematically illustrates a first detection coil according to the embodiment. Figure 4A top view of a second detection coil according to an embodiment is schematically illustrated. Figure 3 and Figure 4 and the following Figure 5 , Figure 10 to Figure 13 and Fig.19 In order to simplify, the first detection coil 20 is replaced by Figure 2 The wiring pattern shown in the figure is adopted Figure 3 Similarly, the second detection coil 30 is also Figure 4 Schematic description as shown.

[0067] Next, the structure of the second detection coil 30 will be described. Figure 5 As shown, there are five second detection coils 30 (31 to 35), but the structures of the second detection coils 30 are the same. Therefore, the structure of the second detection coil 31 is described here, and the description of the structures of the other second detection coils 32 to 35 is omitted.

[0068] like Figure 4 As shown in FIG. 1 , the second detection coil 30 has two second coils 301 and 302. In addition, the second detection coil 30 is not limited to two. Figure 4 In the embodiment, the two second coils 301 and 302 have the same shape and the same size, but may have different shapes and sizes.

[0069] In a plan view seen from above, the two second coils 301 and 302 are arranged in a direction intersecting the up-down direction 100. In the present embodiment, the two second coils 301 and 302 are arranged side by side.

[0070] The two second coils 301 and 302 are electrically connected in series so as to satisfy the same conditions as the first condition and the second condition of the first detection coil 20 .

[0071] The first condition is that the wiring pattern of one of the two second coils 301 and the wiring pattern of the other of the two second coils 302 are arranged parallel to and close to each other at the boundary 30A between the two adjacent second coils 301 and 302. In addition, the condition corresponding to the first condition may not be satisfied.

[0072] The second condition is that when a current flows through the second detection coil 30, the directions of the currents flowing through the two adjacent second coils 301 and 302 are opposite to each other.

[0073] Specifically, if Figure 4As shown by the arrow in FIG. 1 , when the counterclockwise current I5 flows through the second coil 301, the clockwise current I6 flows through the second coil 302 adjacent to the second coil 301. The counterclockwise current I5 is an example of the current in the first winding direction. The clockwise current I6 is an example of the current in the second winding direction. In the above case, the second coil 301 generates a current from Figure 2 The magnetic flux in the direction from the inner side to the front side of the paper is generated in the second coil 302 Figure 2 The magnetic flux from the front side of the paper to the inner side.

[0074] As described above, in the second detection coil 30, multiple second coils 301 and 302 are electrically connected in series in the following manner: when a current in a first winding direction flows through one of the two adjacent second coils 301, a current in a second winding direction, which is opposite to the first winding direction, flows through the other of the two adjacent second coils 302.

[0075] When the two second coils 301 and 302 are electrically connected in series as described above, similarly to when current flows through the first detection coil 20 , when current flows through the second detection coil 30 , currents flowing through adjacent wiring patterns have the same direction.

[0076] The number of turns of each of the second coils 301 and 302 is 2, but the number of turns is not limited to 2. Furthermore, the number of turns of the second coils 301 and 302 may be different from each other.

[0077] like Figure 3 As shown, the first detection coil 20 and its surrounding area include a boundary portion 20A, a peripheral portion 20B and a surrounding portion 20C. The boundary portion 20A is a wiring pattern constituting a boundary between two adjacent first coils in the first detection coil 20 and an area around it. The peripheral portion 20B is a wiring pattern constituting an outer edge of the first detection coil 20 and an area around it. The surrounding portion 20C is an area surrounded by each wiring pattern among the first coils 201, 202, 203, and 204 of the first detection coil 20.

[0078] The boundary portion 20A includes a main portion 20Aa and end portions 20Ab and 20Ac. The end portion 20Ab is a boundary portion between two adjacent first coils at the outer edge portion of the first detection coil 20 when viewed from above. The end portion 20Ac is a boundary portion between a plurality of adjacent first coils in an area that is not an outer edge portion of the first detection coil 20 when viewed from above. The area that is not an outer edge portion of the first detection coil 20 when viewed from above refers to the inside of the first detection coil 20 when viewed from above. The inside of the first detection coil 20 when viewed from above refers to the area inside the wiring patterns 201A, 202A, 203A, and 204A when viewed from above. In the present embodiment, the end portion 20Ac is located in the center of the first detection coil 20 in the inside of the first detection coil 20 when viewed from above. In addition, the end portion 20Ac may also be located in an area that is not an outer edge portion and is not a center portion of the first detection coil 20. The main portion 20Aa is the area of ​​the boundary portion 20A excluding the end portions 20Ab and 20Ac.

[0079] like Figure 4 As shown, the second detection coil 30 and its surrounding area include a boundary portion 30A, a peripheral portion 30B and a surrounding portion 30C. The boundary portion 30A is a wiring pattern constituting a boundary between two adjacent second coils in the second detection coil 30 and an area around it. The peripheral portion 30B is a wiring pattern constituting an outer edge of the second detection coil 30 and an area around it. The surrounding portion 30C is an area surrounded by each wiring pattern in the second coils 301 and 302 of the second detection coil 30.

[0080] The boundary portion 30A includes a main portion 30Aa and an end portion 30Ab. The end portion 30Ab is located at both ends of the boundary portion 30A, and is a boundary portion of two adjacent second coils 301 and 302 at the outer edge of the second detection coil 30. The main portion 30Aa is the area of ​​the boundary portion 30A excluding the end portion 30Ab. In addition, in the present embodiment, the second detection coil 30 does not have an end portion located in the central portion like the end portion 20Ac of the boundary portion 20A of the first detection coil 20, but it may also have such an end portion.

[0081] like Figure 1As shown, the first detection coil 20 and the second detection coil 30 are located between the transmitting coil 2 and the receiving coil 5. Therefore, in the wireless power transmission from the transmitting coil 2 to the receiving coil 5, the magnetic flux generated in the transmitting coil 2 passes through the first detection coil 20 and the second detection coil 30. As a result, an induced current is generated in the first detection coil 20 and the second detection coil 30. Here, the wiring pattern of the first detection coil 20 and the second detection coil 30 is formed to satisfy the above-mentioned second condition. Therefore, the induced currents generated in each of the first coils 201, 202, 203, and 204 of the first detection coil 20 cancel each other, and the induced currents generated in each of the second coils 301 and 302 of the second detection coil 30 cancel each other. As a result, the heat generation of the first detection coil 20 and the second detection coil 30 caused by the magnetic flux generated in the transmitting coil 2 is reduced.

[0082] As will be described later, a voltage is applied to the first detection coil 20 and the second detection coil 30 from the control unit 40. Then, current flows in the first detection coil 20 and the second detection coil 30. Figure 2 and Figure 4 As a result, in the first detection coil 20, the first coils 201 and 204 generate Figure 2 The magnetic flux in the direction from the inner side to the front side of the paper is generated in the first coils 202 and 203. Figure 2 And, in the second detection coil 30, the second coil 301 generates a magnetic flux from the front side to the back side of the paper. Figure 2 The magnetic flux in the direction from the inner side to the front side of the paper is generated in the second coil 302 Figure 2 The magnetic flux from the front side of the paper to the inner side.

[0083] At this time, at the ends 20Ab and 20Ac of the boundary portion 20A of the first detection coil 20, the magnetic fluxes generated by the two adjacent first coils cancel each other out. Similarly, at the end 30Ab of the boundary portion 30A of the second detection coil 30, the magnetic fluxes generated by the two adjacent second coils cancel each other out. As a result, the magnetic flux density is reduced at the ends 20Ab and 20Ac of the boundary portion 20A and the end 30Ab of the boundary portion 30A. Due to the reduction in the magnetic flux density, there is a foreign object 50 (see Figure 1 ), it may be difficult to detect the foreign matter 50. That is, the end portions 20Ab and 20Ac of the boundary portion 20A and the end portion 30Ab of the boundary portion 30A are areas where it is difficult to detect foreign matter, that is, low-sensitivity areas.

[0084] On the other hand, in the region (main portion 20Aa, peripheral portion 20B, surrounding portion 20C) other than the end portions 20Ab and 20Ac of the boundary portion 20A of the first detection coil 20, the magnetic flux density is reduced less or does not reduce as compared with the end portions 20Ab and 20Ac. Similarly, in the region (main portion 30Aa, peripheral portion 30B, surrounding portion 30C) other than the end portion 30Ab of the boundary portion 30A of the second detection coil 30, the magnetic flux density is reduced less or does not reduce as compared with the end portion 30Ab.

[0085] In view of the above, in the foreign object detection device 10, a region different from the low sensitivity region of the second detection coil 30 is arranged to overlap the low sensitivity region of the first detection coil 20. This will be described in detail below.

[0086] Figure 5 A top view of a first detection coil and a second detection coil according to an embodiment is schematically illustrated. Figure 5 As shown, in this embodiment, the foreign object detection device 10 includes five second detection coils 30 (31 to 35). The number of second detection coils 30 included in the foreign object detection device 10 is not limited to five. The foreign object detection device 10 only needs to include at least one second detection coil 30.

[0087] like Figure 5 As shown, when viewed from above, the second detection coil 30 is arranged in a manner overlapping with the first detection coil 20 so that the surrounding portion 30C of the second coil 301 overlaps with the end portions 20Ab, 20Ac of the boundary portion 20A of the first detection coil 20. Alternatively, the second detection coil 30 may be arranged in a manner overlapping with the first detection coil 20 so that the surrounding portion 30C of the second coil 302 overlaps with the end portions 20Ab, 20Ac of the boundary portion 20A of the first detection coil 20 when viewed from above.

[0088] In the present embodiment, the surrounding portion 30C of the second detection coil 31 is disposed on the end portion 20Ac of the boundary portion 20A of the first detection coil 20 .

[0089] That is, when viewed from above, the surrounding portion 30C of the second detection coil 31 overlaps with an end portion 20Ac of the boundary portion 20A of the first detection coil 20, which is located in a region that is not the outer edge of the first detection coil 20 (inside the first detection coil 20). When viewed from above, the end portion 20Ac of the boundary portion 20A overlapping with the surrounding portion 30C of the second detection coil 31 is surrounded by the plurality of first coils 201 to 204.

[0090] Furthermore, the surrounding portion 30C of the second detection coil 32 is arranged on the end portion 20Ab of the boundary portion 20A of the first coils 201 and 202. The surrounding portion 30C of the second detection coil 33 is arranged on the end portion 20Ab of the boundary portion 20A of the first coils 202 and 204. The surrounding portion 30C of the second detection coil 34 is arranged on the end portion 20Ab of the boundary portion 20A of the first coils 203 and 204. The surrounding portion 30C of the second detection coil 35 is arranged on the end portion 20Ab of the boundary portion 20A of the first coils 201 and 203.

[0091] That is, in a plan view, the surrounding portion 30C of the second detection coils 32 , 33 , 34 , 35 overlaps with an end portion of the boundary portion 20A of the first detection coil 20 located at the outer edge of the first detection coil 20 .

[0092] The outer edge of the first detection coil 20 when viewed from above refers to, for example, the area where the wiring patterns 201A, 202A, 203A, and 204A are located when viewed from above. When viewed from above, the end 20Ab of the boundary portion 20A overlapping the surrounding portion 30C of the second detection coils 32, 33, 34, and 35 is not completely surrounded by the plurality of first coils 201 to 204. For example, a portion of the end 20Ab of the boundary portion 20A overlapping the surrounding portion 30C of the second detection coil 32 ( Figure 2 The lower half of the paper) is surrounded by the two first coils 201 and 202, and the remaining part ( Figure 2 The upper part of the paper) is not surrounded by the first coil.

[0093] As described above, by arranging the first detection coil 20 and the second detection coil 30 in an overlapping manner when viewed from above, the following effects can be achieved. That is, even when the foreign matter 50 located in the low sensitivity area of ​​the first detection coil 20 cannot be detected, the foreign matter 50 located in the low sensitivity area can be detected by detecting the second detection coil 30 that is overlapped and arranged in the low sensitivity area.

[0094] In this embodiment, each second detection coil 30 is smaller than the first detection coil 20 when viewed from above. However, the second detection coil 30 may be larger than the first detection coil 20 when viewed from above. For example, the second detection coil 30 may have four coils like the first detection coil 20.

[0095] Alternatively, the second detection coil 30 may be arranged so as to overlap with the first detection coil 20 in a plan view so that the surrounding portion 30C of the boundary portion 30A overlaps with a portion of the main portion 20Aa of the boundary portion 20A in addition to overlapping with the end portions 20Ab and 20Ac of the boundary portion 20A. That is, in a plan view, the second detection coil 30 is arranged so that the area surrounded by the wiring pattern of the second coil overlaps with a portion of the boundary portion 20A of the first coil including the end portions 20Ab and 20Ac of the boundary portion 20A of the first coil.

[0096] Figure 1 The control unit 40 shown in the figure can apply voltage to the first detection coil 20 and the second detection coil 30. The control unit 40 determines the presence or absence of the foreign object 50 based on the resonance waveform generated by the first detection coil 20 and the second detection coil 30.

[0097] Figure 6 A block diagram schematically illustrates a control unit of an embodiment. Figure 6 As shown, the control unit 40 includes a microcontroller (MCU) 41 , a voltage application circuit 42 , a search coil (SC) switching unit 43 , and a switch 44 .

[0098] MCU41 performs operations for realizing the above-mentioned voltage application and determination of the presence or absence of foreign matter 50. The voltage application circuit 42 has a circuit for performing amplification and the like for applying a voltage of an appropriate level to the first detection coil 20 and the second detection coil 30 according to a command from MCU41. In addition, the voltage application circuit 42 sends the resonant waveform from the first detection coil 20 and the second detection coil 30 to MCU41. The SC switching unit 43 switches the switch 44 based on the command from MCU41 to send the voltage from the voltage application circuit 42 to the detection coils 20, 31, 32, 33, 34, 35 corresponding to the command.

[0099] from Figure 6 The signal lines SC20, SC31, SC32, SC33, SC34, and SC35 extending from the switch 44 are respectively electrically connected to the first detection coil 20, the second detection coil 31, the second detection coil 32, the second detection coil 33, the second detection coil 34, and the second detection coil 35. Each detection coil 20, 31, 32, 33, 34, and 35 has a signal line electrically connected to the switch 44 of the control unit 40 and a ground line electrically connected to the reference potential of the control unit 40. Figure 2 The signal line SC20 shown is electrically connected to the switch 44 of the control unit 40. Figure 2 The ground line GND shown is electrically connected to the reference potential of the control unit 40. Figure 3 and Figure 4 In the diagram, signal and ground wires are omitted.

[0100] The structure of the control unit 40 is not limited to Figure 6 The structure shown. For example, the control unit 40 may also include a memory and a CPU (Central Processing Unit). In this case, for example, the above-mentioned operations are performed by the CPU executing a program stored in the memory. And, for example, the control unit 40 may also be composed of a circuit capable of performing the above-mentioned operations. Such a circuit is, for example, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. The control unit 40 may also be implemented by combining the aforementioned structures. For example, the control unit 40 may also include a memory, a CPU, and an ASIC.

[0101] In this embodiment, the control unit 40 selectively applies voltage to the first detection coil 20 and the second detection coil 30, and determines the presence or absence of the foreign matter 50 based on the resonance waveform generated in the first detection coil 20 and the second detection coil 30 due to the applied voltage.

[0102] Figure 7 A graph showing voltage versus time when a voltage is applied to a detection coil is schematically shown. Figure 7 As shown, the control unit 40 applies a pulse voltage to the selected detection coil (the first detection coil 20 and any one of the second detection coils 31 to 35) selected by the switch 44. The first detection coil 20 and the second detection coil 30 form a parallel LC resonant circuit. Therefore, a resonant waveform is generated in the selected detection coil relative to the applied pulse voltage.

[0103] When there is no foreign matter 50 on the detection coil, Figure 7 On the other hand, when a foreign object 50 is present on the selected detection coil, a resonance waveform is generated. Figure 7 The resonant waveform is as shown in the lower layer. Figure 7 The period ratio of the resonant waveform shown in the upper layer is Figure 7 The period of the resonant waveform shown in the lower layer of is longer. The control unit 40 determines the presence or absence of the foreign matter 50 based on the difference in the period. A predetermined voltage threshold value Vth and a predetermined time threshold value Tth are stored in a memory (not shown) in the control unit 40.

[0104] The voltage threshold Vth is used to set the timing of the count start of the timing circuit built into the control unit 40. When the voltage value of the resonant waveform exceeds the voltage threshold Vth, the timing circuit starts counting. The control unit 40 uses the timing circuit to count the number of times the vibration frequency of the resonant waveform reaches a preset value ( Figure 7 After determining whether there is a foreign object 50, the timing circuit is reset.

[0105] The vibration time TwoF0 when there is no foreign matter 50 on the selected detection coil is measured in advance and stored in the memory in the control unit 40. The control unit 40 compares the vibration time TwF0 measured by the timing circuit in the judgment of the presence or absence of the foreign matter 50 with the vibration time TwoF0 stored in the memory, and calculates the difference ΔT between the two vibration times. The difference ΔT is compared with the time threshold Tth stored in the memory. The period of the resonant waveform when there is a foreign matter 50 on the selected detection coil is shorter than the period of the resonant waveform when there is no foreign matter 50 on the selected detection coil. The control unit 40 determines that there is no foreign matter 50 on the selected detection coil when the difference ΔT is less than the time threshold Tth, and determines that there is a foreign matter 50 on the selected detection coil when the difference ΔT is greater than the time threshold Tth. In addition, in the present embodiment, when the difference ΔT is the same as the time threshold Tth, the control unit 40 determines that there is no foreign matter 50 on the selected detection coil, but it can also be determined that there is a foreign matter 50.

[0106] Below, refer to Figure 8 as well as Fig. 9 The operation of foreign object detection by the foreign object detection device 10 will be described. Figure 8 A flowchart for explaining the procedure of foreign matter detection by the foreign matter detection device is shown as an example. Fig. 9 A flowchart for explaining the procedure of determining the presence or absence of foreign matter by the foreign matter detection device is shown as an example.

[0107] The foreign object detection by the foreign object detection device 10 is performed, for example, at predetermined time intervals (for example, 1 second) during wireless power supply by the wireless power supply device 1 .

[0108] like Figure 8 As shown, in foreign matter detection, the control unit 40 first detects whether there is a foreign matter 50 on the first detection coil 20, for example, whether there is a foreign matter 50 directly above the first detection coil 20 on the upper surface of the transmitting side cover 3 (S10). Next, the control unit 40 detects whether there is a foreign matter 50 on the second detection coil 30, for example, whether there is a foreign matter 50 directly above the second detection coil 30 on the upper surface of the transmitting side cover 3 (S20~S60). In the present embodiment, the control unit 40 detects whether there is a foreign matter 50 in the order of the second detection coils 31, 32, 33, 34, and 35 (S20~S60). That is, in the present embodiment, the control unit 40 selectively applies voltage to the first detection coil 20 and the second detection coil 30. Furthermore, after detecting whether there is a foreign matter 50 on the first detection coil 20, the control unit 40 detects whether there is a foreign matter 50 on the second detection coil 30. In addition, the order of foreign matter detection is not limited to Figure 8 For example, it is also possible to Figure 8 On the contrary, after detecting the presence or absence of the foreign object 50 on the second detection coil 30 , the control unit 40 detects the presence or absence of the foreign object 50 on the first detection coil 20 .

[0109] exist Figure 8 In each step (S10 to S60) shown in FIG. Fig. 9 The following refers to Fig. 9 The process of determining the presence or absence of foreign matter executed in step S10 will be described.

[0110] like Fig. 9 As shown, the SC switching unit 43 sets the switch 44 to the signal line SC20 based on the command from the MCU 41. As a result, the control unit 40 is electrically connected to the first detection coil 20 (S110). At this time, the control unit 40 and the second detection coil 30 are not electrically connected.

[0111] Next, the voltage application circuit 42 applies a pulse voltage to the first search coil 20 selected by the switch 44 according to a command from the MCU 41 ( S120 ). Thus, the resonance waveform generated in the first search coil 20 is sent to the control unit 40 .

[0112] As described above, the control unit 40 calculates the difference ΔT, and compares the difference ΔT with the time threshold Tth ( S130 ).

[0113] When the difference ΔT is greater than the time threshold Tth (S130: No), the control unit 40 determines that there is a foreign object on the first detection coil 20 (S150). On the other hand, when the difference ΔT is less than the time threshold Tth (S130: Yes), the control unit 40 determines that there is no foreign object on the first detection coil 20 (S140). As described above, in step S10, the control unit 40 determines whether there is a foreign object 50 on the first detection coil 20 by applying a voltage to the first detection coil.

[0114] When it is determined that there is a foreign object 50 on the first detection coil 20, the control unit 40 sends a power supply stop signal to the transmission control unit 4 (S150). The transmission control unit 4 that receives the power supply stop signal stops applying voltage to the transmission coil 2. In this case, wireless power supply is stopped. Figure 8 The foreign matter detection processing shown is also stopped.

[0115] When it is determined that there is no foreign object 50 on the first detection coil 20 (S140), the control unit 40 then executes Figure 8 That is, the control unit 40 then determines whether there is a foreign object on the second detection coil 30. After step S20, the same processing as step S10 is performed. Fig. 9 Processing shown.

[0116] For example, in step S20, Fig. 9 In the process shown, the control unit 40 is electrically connected to the second detection coil 31 (S110), and applies a pulse voltage to the second detection coil 31 (S120). Next, the control unit 40 calculates the difference ΔT, and compares the difference ΔT with the time threshold Tth (S130). The control unit 40 determines that there is no foreign matter on the second detection coil 31 (S140) when the difference ΔT is less than the time threshold Tth (S130: Yes), and determines that there is a foreign matter on the second detection coil 31 (S150) when the difference ΔT is greater than the time threshold Tth (S130: No). As described above, in step S20, the control unit 40 determines whether there is a foreign matter 50 on the second detection coil 31 by applying a voltage to the second detection coil 31. The determination of whether there is a foreign matter 50 on the second detection coils 32, 33, 34, and 35 is performed in the same manner.

[0117] According to the present embodiment, the control unit 40 determines whether there is a foreign object on the first detection coil 20 by applying a voltage to the first detection coil 20, and determines whether there is a foreign object on the second detection coil 30 by applying a voltage to the second detection coil 30 (31 to 35). That is, the detection method of the present embodiment is not an external excitation method, but a self-excitation method that detects the presence of a foreign object based on the voltage applied to the self-coil. In the self-excitation method, the low-sensitivity area that is an area where foreign objects are difficult to detect is not the entire area of ​​the boundary 20A of the two adjacent first coils, but the end portions 20Ab and 20Ac of the boundary 20A of the first coil.

[0118] In this embodiment, the second detection coil 30 is configured so that the surrounding portion 30C, which is the area surrounded by the wiring pattern of the second coil 301, overlaps with the end portions 20Ab and 20Ac of the boundary portion 20A of the first coil when viewed from above. Thus, even when it is difficult to detect a foreign object by applying a voltage to the first detection coil 20 due to the presence of a foreign object in the low-sensitivity area of ​​the first detection coil 20, the foreign object can be detected by applying a voltage to the second detection coil 30.

[0119] Furthermore, in the present embodiment, when viewed from above, each of the second detection coils 31 to 35 is arranged so that the surrounding portion 30C, which is the area surrounded by the wiring patterns 301A and 301B of the second coil 301, overlaps a portion of the boundary portion 20A of the first coil. That is, in the present embodiment, when viewed from above, each of the second detection coils 31 to 35 is arranged so that it overlaps not the entire area of ​​the boundary portion 20A of the first coil but a portion thereof. Therefore, in the present embodiment, the size of each of the second detection coils 31 to 35 can be reduced.

[0120] When viewed from above, the ends 20Ab and 20Ac of the boundary portion 20A of the first coil may be located at the outer edge of the first detection coil 20 and outside the outer edge of the first detection coil 20 (inside the first detection coil 20). In the case of detecting a foreign object on the first detection coil 20, the necessity of detecting the foreign object inside the first detection coil 20 is higher than the necessity of detecting the foreign object at the outer edge of the first detection coil 20. According to the present embodiment, when viewed from above, the end 20Ac of the boundary portion 20A of the first coil overlapping the surrounding portion 30C which is the area surrounded by the wiring patterns 301A and 301B of the second coil 301 is surrounded by a plurality of first coils 201 to 204. That is, when viewed from above, the end 20Ac of the boundary portion 20A of the first coils 201 to 204 overlapping the surrounding portion 30C is located in the central portion of the first detection coil 20 which is a part of the interior of the first detection coil 20. That is, according to the present embodiment, the reliability of foreign object detection can be improved in an area where the necessity of foreign object detection is high.

[0121] Each second detection coil 31 to 35 may be sized to include the low sensitivity region of the first detection coil 20 in plan view. According to this embodiment, each second detection coil 31 to 35 is smaller than the first detection coil 20 in plan view. Therefore, each second detection coil 31 to 35 can be prevented from becoming excessively large.

[0122] According to the present embodiment, each of the second detection coils 31 to 35 includes two second coils 301 and 302. In this case, each of the second detection coils 31 to 35 can be made smaller than a configuration in which each of the second detection coils 31 to 35 includes three or more second coils.

[0123] When the control unit 40 applies voltage to the first detection coil 20 and the second detection coil 30 in parallel, the magnetic flux generated by the first detection coil 20 and the magnetic flux generated by the second detection coil 30 interact with each other, which may cause false detection of the foreign object 50. According to the present embodiment, the control unit 40 selectively applies voltage to the first detection coil 20 and the second detection coil 30, thereby reducing the possibility of the above-mentioned false detection.

[0124] According to the present embodiment, a voltage can be first applied to the first detection coil 20 to detect whether there is a foreign object in the area other than the low-sensitivity area of ​​the first detection coil 20, and then a voltage can be applied to the second detection coil 30 to detect whether there is a foreign object in the low-sensitivity area of ​​the first detection coil 20. Usually, the proportion of the low-sensitivity area on the first detection coil 20 is smaller than the proportion of the area other than the low-sensitivity area. That is, according to the present embodiment, when detecting whether there is a foreign object on the first detection coil 20, the area occupying a larger proportion is first detected to detect whether there is a foreign object. In this way, foreign object detection can be performed quickly.

[0125] In this embodiment, the first detection coil 20 is as follows Figure 2 and Figure 3 The shapes shown are, but not limited to, these.

[0126] For example, the foreign matter detection device 10 may also include Fig.10 The first detection coil 21 is a quadrilateral as shown. Fig.10 A plan view of a first detection coil showing a modified example is schematically illustrated. The first detection coil 21 includes four first coils 211 to 214. The first detection coil 21 and its surrounding area include a boundary portion 21A, a peripheral portion 21B, and a surrounding portion 21C. The boundary portion 21A includes a main portion 21Aa and end portions 21Ab and 21Ac.

[0127] Furthermore, for example, the foreign matter detection device 10 may also include Fig.11 The first detection coil 22 is circular as shown. Fig.11 A plan view of a first detection coil of a modified example is schematically illustrated. The first detection coil 22 includes eight first coils 221 to 228. The first detection coil 22 and its surrounding area include a boundary portion 22A, a peripheral portion 22B, and a surrounding portion 22C. The boundary portion 22A includes a main portion 22Aa and end portions 22Ab and 22Ac.

[0128] Furthermore, for example, the foreign matter detection device 10 may also include Fig.12 The first detection coil 23 is a quadrilateral as shown. Fig.12 A top view of a first detection coil according to a modified example is schematically illustrated. The first detection coil 23 includes six first coils 231 to 236. The first detection coil 23 and its surrounding area include a boundary portion 23A, a peripheral portion 23B, and a surrounding portion 23C. The boundary portion 23A includes a main portion 23Aa and end portions 23Ab and 23Ac. The first detection coil 23 includes two end portions 23Ac.

[0129] In this embodiment, the second detection coil 30 is as follows Figure 4 The shapes shown are, but not limited to, these.

[0130] For example, the foreign body detection device 10 may also include Fig.13 The second detection coil 36 is circular as shown. Fig.13 A top view of a second detection coil showing a modified example is schematically illustrated. The second detection coil 36 includes two second coils 361 and 362. The second detection coil 36 and its surrounding area include a boundary portion 36A, a peripheral portion 36B, and a surrounding portion 36C. The boundary portion 36A includes a main portion 36Aa and an end portion 36Ab.

[0131] In the wireless power supply device 1 of the present embodiment, a configuration is described in which the transmitter and the receiver are arranged side by side in the vertical direction 100, and the transmitting coil 2 and the receiving coil 5 are opposite to each other in the vertical direction 100, but the configuration is not limited thereto. For example, the transmitter and the receiver may be arranged side by side in a horizontal direction orthogonal to the vertical direction 100, and the transmitting coil 2 and the receiving coil 5 may be opposite to each other in the horizontal direction. That is, the transmitting coil 2 and the receiving coil 5 may also be arranged vertically or the like.

[0132] In the wireless power supply device 1 of this embodiment, a structure is described in which the receiver (receiving coil 5, receiving side cover 6, receiving control unit 7) is arranged above the transmitter (transmitting coil 2, transmitting side cover 3, transmitting control unit 4), and the first detection coil 20 and the second detection coil 30 of the foreign object detection device 10 are arranged inside the transmitting side cover 3, but it is not limited to this. Fig.14 The wireless power supply device of the modified example is schematically illustrated. Fig.14 As in the wireless power supply device 1A shown in the figure, the transmitter is arranged above the receiver, and the first detection coil 20 and the second detection coil 30 of the foreign object detection device 10 are arranged inside the transmission side cover 3.

[0133] In the wireless power supply device 1 of the present embodiment, the configuration in which the first detection coil 20 and the second detection coil 30 of the foreign object detection device 10 are arranged inside the transmission-side cover 3 is described, but the present invention is not limited thereto.

[0134] Fig.15 The wireless power supply device of the modified example is schematically illustrated. Fig.15 In a configuration where the transmitter is arranged above the receiver, as in the wireless power supply device 1B shown, the first detection coil 20 and the second detection coil 30 of the foreign object detection device 10 are arranged inside the receiving-side cover 6 .

[0135] Fig.16 A wireless power supply device of a modified example is schematically illustrated. Fig.16 In a configuration where the receiver is arranged above the transmitter, as in the wireless power supply device 1C shown, the first detection coil 20 and the second detection coil 30 of the foreign object detection device 10 are arranged inside the receiving-side cover 6 .

[0136] In the present embodiment, the wireless power supply device 1 is described as including the transmission control unit 4 and the reception control unit 7 , but the present invention is not limited thereto.

[0137] Fig.17 A wireless power supply device of a modified example is schematically illustrated. For example, Fig.17 The wireless power supply device 1D shown in the figure includes the transmission control unit 4 but does not include the reception control unit 7. Figure 1Compared with the wireless power supply device 1 shown, the number of components mounted on the receiver can be reduced.

[0138] Fig.17 In the wireless power supply device 1D shown in FIG. 1 , the transmitter includes a communication unit 8 and the receiver includes a communication unit 9. The communication unit 8 is electrically connected to the transmission control unit 4. The communication unit 9 is electrically connected to the receiving coil 5. Fig.17 As shown by the dotted arrows, the communication unit 8 and the communication unit 9 are configured to be able to communicate wirelessly with each other. Fig.17 In the case of the structure shown in FIG. 1 , the transmission control unit 4 adjusts (controls) the output voltage based on the information transmitted from the communication unit 9 of the receiver to the communication unit 8 of the transmitter. Fig.17 In the wireless power supply device 1D shown in FIG. Figure 1 In the wireless power supply device 1 shown, the output voltage is adjusted by the reception control unit 7 .

[0139] In addition, the wireless power supply device 1D is Figure 1 The wireless power supply device 1 shown in the figure has a structure in which the receiving control unit 7 is removed and the communication units 8 and 9 are added, but the present invention is not limited to this. For example, the wireless power supply device may also be configured as follows: Fig.14 The wireless power supply device 1A shown in the figure has the reception control unit 7 removed and communication units 8 and 9 added.

[0140] Fig.18 A wireless power supply device of a modified example is schematically illustrated. For example, Fig.18 The wireless power supply device 1E shown in the figure includes the reception control unit 7 but does not include the transmission control unit 4. Fig.15 Compared with the wireless power supply device 1B shown in the figure, the number of components mounted on the transmitter can be reduced.

[0141] exist Fig.18 In the wireless power supply device 1E shown in FIG. 1 , the transmitter includes a communication unit 8 and the receiver includes a communication unit 9. The communication unit 8 is electrically connected to the transmission coil 2. The communication unit 9 is electrically connected to the reception control unit 7. Fig.18 As shown by the dotted arrows, the communication unit 8 and the communication unit 9 are configured to be able to communicate wirelessly with each other. Fig.18 In the case of the structure shown in FIG. 1 , the receiving control unit 7 adjusts (controls) the voltage output from the receiving coil 5. For example, a certain output is always (or at regular intervals) performed from the communication unit 8 of the transmitter. The receiving control unit 7 obtains the information of the output via the communication unit 9, and controls the output voltage of the receiving coil 5 based on the obtained information so that an appropriate voltage can be supplied to the battery or the like. Fig.18 In the wireless power supply device 1E shown in the figure which does not include the transmission control unit 4, since control on the power transmission side is not necessary, the time until the power supply starts can be shortened.

[0142] In addition, the wireless power supply device 1E is Fig.15 The wireless power supply device 1B shown in the figure has a structure in which the transmission control unit 4 is removed and the communication units 8 and 9 are added, but the present invention is not limited to this. For example, the wireless power supply device may also be configured from Fig.16 The wireless power supply device 1C shown in the figure has the transmission control unit 4 removed and communication units 8 and 9 added.

[0143] In the wireless power supply device 1 of the present embodiment, a structure in which the second detection coil 30 overlaps all the ends 20Ab and 20Ac of the first detection coil 20 is described, but it is not limited to this. For example, the second detection coil 30 may overlap the end 20Ac of the first detection coil 20, and the second detection coil 30 may not overlap the end 20Ab of the first detection coil 20. In addition, for example, the second detection coil 30 may overlap only a part of the end 20Ab of the first detection coil 20.

[0144] In the wireless power supply device 1 of this embodiment, Figure 5 Although the structure in which the boundary portion 30A of the second detection coils 32 to 35 arranged to overlap the outer edge portion of the first detection coil 20 in a plan view partially overlaps the first detection coil 20 is described, the present invention is not limited to this. Fig.19 A top view of a first detection coil and a second detection coil showing a modified example is schematically illustrated. Fig.19 As shown, in a plan view, the boundary portion 30A of the second detection coils 32 to 35 may be located outside the first detection coil 20 without overlapping with the first detection coil 20 .

[0145] according to Fig.19 In the structure shown, when viewed from above, the boundary 30A between the two adjacent second coils 301 and 302 is located outside the first detection coil 20. That is, when viewed from above, the end 30Ab of the boundary 30A between the two adjacent second coils 301 and 302 (the low sensitivity area of ​​the second detection coil 30) is located outside the first detection coil 20. As a result, the interaction of the magnetic flux between the first detection coil 20 and the second detection coil 30 can be reduced.

[0146] In this embodiment, the structure in which the foreign object detection device 10 is provided in the wireless power supply device 1 is described, but the foreign object detection device 10 is not limited to the wireless power supply device 1. The foreign object detection device 10 can be applied to any device as long as it is a device that can detect the presence of foreign objects based on the voltage applied to the self-coil. For example, the foreign object detection device 10 can be applied to a food inspection device, a garbage sorting machine, etc.

[0147] The above description can also be expressed as follows.

[0148] (1) A foreign body detection device 10 according to one embodiment of the present invention comprises: a first detection coil 20 having a plurality of first coils 201, 202, 203, and 204 arranged in a plan view; at least one second detection coil 30 having a plurality of second coils 301, 302 arranged in a plan view; and a control unit 40 capable of applying voltage to the first detection coil 20 and the second detection coil 30, wherein the plurality of first coils 201, 202, 203, and 204 in the first detection coil 20 are electrically connected in series in the following manner: When a current I1, I4 in a first winding direction flows through one of the two adjacent first coils 201, 204, a current I2, I3 in a second winding direction opposite to the first winding direction flows through the other of the two adjacent first coils 202, 203. In the second detection coil 30, a plurality of the second coils 301, 302 are electrically connected in series in the following manner: when a current I5 in the first winding direction flows through one of the two adjacent second coils 301, a current I6 in the second winding direction flows through the other of the two adjacent second coils 302. The current I6 in the second winding direction, in the first detection coil 20, at the boundary portion 20A between two adjacent first coils, the wiring (wiring patterns 201B, 201C, 204B, 204C) possessed by one of the two first coils 201, 204 and the wiring (wiring patterns 202B, 202C, 203B, 203C) possessed by the other of the two first coils 202, 203 are arranged parallel to and close to each other, and the control unit 40 determines whether the first detection coil 20 is in operation or not by applying a voltage to the first detection coil 20. 20, and whether there is foreign matter 50 on the second detection coil 30 is determined by applying voltage to the second detection coil 30. When viewed from above, the second detection coil 30 is configured so that an area (surrounding portion 30C) surrounded by the wiring (wiring patterns 301A, 301B) of the second coil 301 overlaps with a portion of the boundary portion 20A of the first coils 201, 202, 203, 204, including the ends 20Ab, 20Ac of the boundary portion 20A of the first coils 201, 202, 203, 204.

[0149] (2) In the foreign object detection device 10 of (1), it may be that, when viewed from above, the end 20Ac of the boundary portion 20A of the first coils 201, 202, 203, 204 overlapping with the area (surrounding portion 30C) surrounded by the wiring of the second coil 301 is surrounded by multiple first coils 201, 202, 203, 204.

[0150] (3) The first detection coil may have four first coils arranged in two rows and two columns when viewed from above, and the second detection coil may be configured so that an area surrounded by the wiring of the second coil overlaps with the boundary portion located in the center of the four first coils when viewed from above.

[0151] (4) In the foreign object detection device 10 according to any one of (1) to (3), one of the second detection coils 30 may be smaller than the first detection coil 20 in a plan view.

[0152] (5) In the foreign object detection device 10 of any one of (1) to (4), it may be that, in the second detection coil 30 overlapping with the outer edge portion (wiring patterns 201A, 202A, 203A, 204A) of the first detection coil 20 when viewed from above, the boundary portion 30A between two adjacent second coils 301 and 302 is located outside the first detection coil 20.

[0153] (6) In the foreign object detection device 10 according to any one of (1) to (5), the second detection coil 30 may include two second coils 301 and 302 .

[0154] (7) In the foreign object detection device 10 according to any one of (1) to (6), the control unit 40 may selectively apply voltage to the first detection coil 20 and the second detection coil 30 .

[0155] (8) In the foreign object detection device 10 of (7), the control unit 40 may apply voltage to the second detection coil 30 to determine whether there is a foreign object 50 on the first detection coil 20 after applying voltage to the first detection coil 20 to determine whether there is a foreign object 50 on the first detection coil 20, and then apply voltage to the second detection coil 30 to determine whether there is a foreign object 50 on the second detection coil 30.

[0156] (9) A coil device 15 according to one embodiment of the present invention comprises: a first detection coil 20 having a plurality of first coils 201, 202, 203, 204 arranged in a plan view; and at least one second detection coil 30 having a plurality of second coils 301, 302 arranged in a plan view, wherein in the first detection coil 20, the plurality of first coils 201, 202, 203, 204 are electrically connected in series in the following manner: when a current I1, I4 in a first winding direction flows through one of two adjacent first coils 201, 204, a current I2, I3 in a second winding direction opposite to the first winding direction flows through the other of the two adjacent first coils 202, 203; and in the second detection coil 30, the plurality of second coils 301, 302 are electrically connected in series in the following manner: when a current I5 in the first winding direction flows through one of the two adjacent second coils 301, The other one 302 of the two adjacent second coils passes through a current I6 in the second winding direction. In the first detection coil 20, at the boundary portion 20A of the two adjacent first coils, the wiring (wiring patterns 201B, 201C, 204B, 204C) possessed by one of the two first coils 201, 204 and the wiring (wiring patterns 202B, 202C, 203B, 203C) possessed by the other one 202, 203 of the two first coils are arranged parallel to and close to each other. When viewed from above, the second detection coil 30 is arranged so that the area (surrounding portion 30C) surrounded by the wiring (wiring patterns 301A, 301B) of the second coil 301 overlaps with a portion of the boundary portion 20A of the first coils 201, 202, 203, 204, including the ends 20Ab, 20Ac of the boundary portion 20A of the first coils 201, 202, 203, 204.

[0157] In addition, by appropriately combining any of the various embodiments described above, the effects possessed by each can be achieved.

[0158] Although the present disclosure is fully described in relation to the preferred embodiments with appropriate reference to the drawings, various modifications and variations will be apparent to those skilled in the art, and such modifications and variations should be understood to be included within the scope of the present invention as long as they do not depart from the scope of the appended claims.

[0159] Description of symbols

[0160] 10Foreign matter detection device

[0161] 20First detection coil

[0162] 20A Boundary Department

[0163] 20Ab end

[0164] 20Ac end

[0165] 201 First Coil

[0166] 201B Wiring Pattern (Wiring)

[0167] 201C Wiring Pattern (Wiring)

[0168] 202 first coil

[0169] 202B Wiring Pattern (Wiring)

[0170] 202C Wiring Pattern (Wiring)

[0171] 203 First Coil

[0172] 203B Wiring Pattern (Wiring)

[0173] 203C Wiring Pattern (Wiring)

[0174] 204 first coil

[0175] 204B wiring pattern (wiring)

[0176] 204C Wiring Pattern (Wiring)

[0177] 30 Second detection coil

[0178] 30C Surrounding portion (area surrounded by the wiring of the second coil)

[0179] 301 Second Coil

[0180] 301A Wiring Pattern (Wiring)

[0181] 301B Wiring Pattern (Wiring)

[0182] 302 Second Coil

[0183] 302A Wiring Pattern (Wiring)

[0184] 302B wiring pattern (wiring)

[0185] 40 Control Department

Claims

1. A foreign body detection device, comprising: A first detection coil having a plurality of first coils arranged in a plan view; at least one second detection coil having a plurality of second coils arranged in a plan view; and a control unit capable of applying a voltage to the first detection coil and the second detection coil, In the first detection coil, a plurality of the first coils are electrically connected in series in the following manner: when a current in a first winding direction flows through one of two adjacent first coils, a current in a second winding direction opposite to the first winding direction flows through the other of the two adjacent first coils. In the second detection coil, a plurality of the second coils are electrically connected in series in the following manner: when a current in the first winding direction flows through one of two adjacent second coils, a current in the second winding direction flows through the other of the two adjacent second coils. In the first detection coil, at a boundary between two adjacent first coils, a wiring included in one of the two first coils and a wiring included in the other of the two first coils are arranged parallel to and close to each other. The control unit determines whether there is a foreign object on the first detection coil by applying a voltage to the first detection coil, and determines whether there is a foreign object on the second detection coil by applying a voltage to the second detection coil. The second detection coil is arranged so that a region surrounded by wiring of the second coil overlaps a portion of the boundary portion of the first coil including an end portion of the boundary portion of the first coil in a plan view.

2. The foreign matter detection device according to claim 1, in, In a plan view, an end portion of the boundary portion of the first coil overlapping with a region surrounded by wiring of the second coil is surrounded by a plurality of the first coils.

3. The foreign matter detection device according to claim 2, in, The first detection coil has four first coils arranged in two rows and two columns in a plan view, The second detection coil is arranged so that a region surrounded by wiring of the second coil overlaps the boundary portion located in the center of the four first coils in a plan view.

4. The foreign matter detection device according to any one of claims 1 to 3, in, In a plan view, one of the second detection coils is smaller than the first detection coil.

5. The foreign matter detection device according to any one of claims 1 to 4, in, In a plan view, in the second detection coil overlapping the outer edge portion of the first detection coil, a boundary portion between two adjacent second detection coils is located outside the first detection coil.

6. The foreign matter detection device according to any one of claims 1 to 5, in, The second detection coil has two second coils.

7. The foreign matter detection device according to any one of claims 1 to 6, in, The control unit selectively applies a voltage to the first detection coil and the second detection coil.

8. The foreign matter detection device according to claim 7, in, After applying voltage to the first detection coil to determine whether there is a foreign object on the first detection coil, the control unit applies voltage to the second detection coil to determine whether there is a foreign object on the second detection coil.

9. A coil device comprising: A first detection coil having a plurality of first coils arranged in a plan view; and at least one second detection coil having a plurality of second coils arranged in a plan view, In the first detection coil, a plurality of the first coils are electrically connected in series in the following manner: when a current in a first winding direction flows through one of two adjacent first coils, a current in a second winding direction opposite to the first winding direction flows through the other of the two adjacent first coils. In the second detection coil, a plurality of the second coils are electrically connected in series in the following manner: when a current in the first winding direction flows through one of two adjacent second coils, a current in the second winding direction flows through the other of the two adjacent second coils. In the first detection coil, at a boundary between two adjacent first coils, a wiring included in one of the two first coils and a wiring included in the other of the two first coils are arranged parallel to and close to each other. The second detection coil is arranged so that a region surrounded by wiring of the second coil overlaps a portion of the boundary portion of the first coil including an end portion of the boundary portion of the first coil in a plan view.

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