JP6361515B2 - Power transmission system and foreign object detection device - Google Patents

Description

  The present invention relates to a power transmission system and a foreign object detection device.

  The non-contact power feeding system includes a power transmission coil device and a power receiving coil device, and realizes non-contact power transmission by using electromagnetic induction and magnetic field resonance between the coils. As an application destination of the non-contact power supply system, for example, a power supply system of an electric vehicle and a plug-in hybrid vehicle can be given. In this case, the power receiving coil device is mounted on the vehicle.

  In such a non-contact power feeding system, since there is a gap between the power transmission coil device and the power receiving coil device, foreign matter may enter the gap. In particular, when foreign materials of conductive materials such as coins and iron nails enter between the power transmission coil device and the power reception coil device, the power supply efficiency may be reduced. For this reason, the mechanism for detecting the foreign material which entered between the power transmission coil apparatus and the receiving coil apparatus is desired.

  Patent Document 1 discloses a foreign object detection device in which linear electric wirings are arranged in a comb shape so as to alternate, and the presence or absence of a foreign object is determined by detecting the presence or absence of a short circuit between the electric wirings. Yes. Patent Document 2 discloses a non-contact power feeding device in which a foreign object detection coil is provided between a power transmission coil and a power reception coil, and the presence or absence of a foreign object is determined based on an induced voltage of the foreign object detection coil. Patent Document 3 discloses various shapes of the foreign object detection coil.

JP 2006-13225 A JP 2012-249401 A Special table 2014-526871 gazette

  Since the foreign object detection device described in Patent Document 1 detects a foreign object based on the presence or absence of a short circuit between electrical wires, it cannot detect a foreign material that is not in contact with two or more electrical wires. On the other hand, in the non-contact power feeding device described in Patent Document 2, since the foreign object is detected by the induced voltage caused by the change in the magnetic flux of the foreign object detection coil, depending on the positional relationship between the foreign object detection coil and the foreign object, for example, In some cases, the change in magnetic flux due to the presence of the magnetic flux hardly affects the amount of magnetic flux interlinked with the foreign object detection coil. In this case, foreign matter may not be detected. Hereinafter, a position on the coil device that cannot be detected by the foreign object detection coil is referred to as a dead zone. Further, when the foreign object detection coil is formed by twisting a plurality of loops as in Patent Document 3, there is a dead zone at the boundary between adjacent loops.

  The present invention provides a power transmission system and a foreign object detection device capable of improving the detection accuracy of a foreign object.

  A power transmission system according to one embodiment of the present invention is a power transmission system including a power transmission device including a coil device used for non-contact power feeding and a foreign object detection device for the coil device. This power transmission system is arranged on a casing of a coil device, each including two terminals, a first detection coil and a second detection coil, and one terminal of the first detection coil and one terminal of the second detection coil. A switching unit that selects one of the first detection coil as the first terminal and selects one of the other terminal of the first detection coil and the other terminal of the second detection coil as the second terminal, and a different detection coil The switching part is selected as the first terminal and the second terminal, and the presence or absence of conductive foreign matter is determined depending on whether the connection between the first terminal and the second terminal is in a short circuit state or an open state. While performing the 1st foreign substance determination process to determine, according to the change of the magnetic flux amount which makes the switching part select two terminals of the same detection coil as a 1st terminal and a 2nd terminal, and links the same detection coil Second foreign matter judgment to determine the presence or absence of foreign matter And a control unit that performs processing.

  According to this power transmission system, the first foreign matter determination process is performed in which the presence or absence of conductive foreign matter is determined according to whether the connection between the terminals of the different detection coils is in a short-circuited state or an open state. Second foreign matter determination processing is performed in which the presence or absence of conductive foreign matter is determined in accordance with a change in the amount of magnetic flux interlinking the same detection coil. When a conductive foreign substance exists in a region surrounded by the first detection coil or the second detection coil, the first detection coil and the second detection coil are not short-circuited. For this reason, although such a foreign substance cannot be detected in the first foreign substance determination process, the amount of magnetic flux interlinking the first detection coil or the second detection coil is less than the first detection coil or the first detection coil. Since the amount of magnetic flux interlinking the two detection coils is larger, the foreign matter can be detected by the second foreign matter determination process even if the foreign matter is not in contact with the first detection coil and the second detection coil. In addition, when a foreign object exists outside the region surrounded by the first detection coil and the region surrounded by the second detection coil, the amount of magnetic flux interlinking the first detection coil and the second detection coil is the presence of the foreign material. If not, the amount of magnetic flux interlinking the first detection coil and the second detection coil is substantially the same. For this reason, in the second foreign matter determination process, such a foreign matter cannot be detected, but when the foreign matter is in contact with the first detection coil and the second detection coil, the terminal of the first detection coil and the second Since the terminals of the detection coil are in a short circuit state, the foreign matter can be detected by the first foreign matter determination process. As a result, the foreign object detection accuracy can be improved.

  The control unit further causes the switching unit to select two terminals of the same detection coil as the first terminal and the second terminal, and the connection between the first terminal and the second terminal is in a short circuit state or in an open state. The presence or absence of a failure may be determined depending on the situation. When two terminals of the same detection coil are in an open state, it is considered that the detection coil is physically disconnected, so that it can be determined that a failure exists. Thereby, for example, when it is determined that there is a failure, it is possible to prevent the foreign object detection processing from being performed, and it is possible to prevent erroneous detection of the foreign object due to the detection coil being disconnected.

  The housing may include a cover and a base that define a housing space for housing the coil device. The switching unit may include a plurality of input terminals, and each of the plurality of input terminals may correspond to one of the first detection coil and the second detection coil. The first detection coil and the second detection coil are provided on the cover, and each terminal of the first detection coil and the second detection coil is electrically connected to the corresponding input terminal by attaching the cover to the base. Good. According to this configuration, when the cover is correctly attached to the base, each terminal of the first detection coil and the second detection coil is electrically connected to the corresponding input terminal. On the other hand, when the cover is not correctly attached to the base, each terminal of the first detection coil and the second detection coil is not electrically connected to the corresponding input terminal. For this reason, when the detection coil is not physically disconnected and the cover is correctly attached to the base, the connection between the two terminals of the same detection coil is short-circuited. When the detection coil is physically disconnected, or when the cover is not correctly attached to the base, the two terminals of the same detection coil are opened. Therefore, if two terminals of the same detection coil are in an open state, it is considered that the detection coil is physically disconnected or the cover is not correctly attached to the base, so that there is a failure. Can be determined. Thereby, for example, when it is determined that there is a failure, the user can be urged to correctly attach the cover to the base by notifying the user that the cover is not correctly attached, etc. It becomes possible to suppress the failure of the coil device.

  The control unit may control the power transmission device so as to prohibit power supply for non-contact power supply when it is determined that a failure exists. If it is determined that a failure exists, it is considered that the detection coil is physically disconnected or the cover is not properly attached to the base. In this case, there is a possibility that the foreign object detection device cannot accurately detect the foreign object. For this reason, when it is determined that there is a failure, the non-contact power supply in a state where foreign object detection cannot be normally performed can be suppressed by prohibiting the power supply for the non-contact power supply. In addition, since the cover is not correctly attached to the base, if dust, water, or the like enters the coil device from the outside, the circuit in the coil device may break down. For this reason, when it is determined that there is a failure, by prohibiting the power supply for contactless power supply, contactless power supply in a state where the circuit does not function normally can be suppressed.

  When it is determined that there is a conductive foreign object, the control unit transmits power so as to prohibit power supply for contactless power supply or supply power lower than that for contactless power supply. The device may be controlled.

  The foreign object detection device may include a first detection coil, a second detection coil, and a switching unit, and the power transmission device may include a control unit. Even in such a configuration, it is possible to improve the detection accuracy of the foreign matter.

  The foreign object detection device may include a first detection coil, a second detection coil, a switching unit, and a control unit. Even in such a configuration, it is possible to improve the detection accuracy of the foreign matter.

  The foreign material detection apparatus which concerns on another aspect of this invention is a foreign material detection apparatus for coil apparatuses used for non-contact electric power feeding from a power transmission apparatus. The foreign object detection device is disposed on the casing of the coil device, and each of the first detection coil and the second detection coil includes two terminals, and one terminal of the first detection coil and one of the second detection coils. A switching unit that selects one of the terminals as the first terminal and selects one of the other terminal of the first detection coil and the other terminal of the second detection coil as the second terminal, and a different detection Whether the coil terminal is selected as the first terminal and the second terminal by the switching unit, the presence or absence of conductive foreign matter depending on whether the connection between the first terminal and the second terminal is a short-circuited state or an open state In response to a change in the amount of magnetic flux interlinking the same detection coil, the switching unit selects the two terminals of the same detection coil as the first terminal and the second terminal. 2nd foreign matter judgment to judge the presence or absence of foreign matter And a control unit that performs processing.

  According to this foreign matter detection device, the first foreign matter determination process is performed in which the presence or absence of conductive foreign matter is determined depending on whether the connection between the terminals of the different detection coils is in a short circuit state or an open state. At the same time, a second foreign matter determination process is performed in which the presence or absence of conductive foreign matter is determined according to the change in the amount of magnetic flux interlinking the same detection coil. When a conductive foreign substance exists in a region surrounded by the first detection coil or the second detection coil, the first detection coil and the second detection coil are not short-circuited. For this reason, although such a foreign substance cannot be detected in the first foreign substance determination process, the amount of magnetic flux interlinking the first detection coil or the second detection coil is less than the first detection coil or the first detection coil. Since the amount of magnetic flux interlinking the two detection coils is larger, the foreign matter can be detected by the second foreign matter determination process even if the foreign matter is not in contact with the first detection coil and the second detection coil. In addition, when a foreign object exists outside the region surrounded by the first detection coil and the region surrounded by the second detection coil, the amount of magnetic flux interlinking the first detection coil and the second detection coil is the presence of the foreign material. If not, the amount of magnetic flux interlinking the first detection coil and the second detection coil is substantially the same. For this reason, in the second foreign matter determination process, such a foreign matter cannot be detected, but when the foreign matter is in contact with the first detection coil and the second detection coil, the terminal of the first detection coil and the second Since the terminals of the detection coil are in a short circuit state, the foreign matter can be detected by the first foreign matter determination process. As a result, the foreign object detection accuracy can be improved.

  According to the present invention, the foreign matter detection accuracy can be improved.

It is a figure which shows the example of application of the power transmission system and foreign material detection apparatus which concern on one Embodiment. It is a figure which shows the function structure of the power transmission system which concerns on one Embodiment. It is a figure which shows the example of arrangement | positioning of each component of the foreign material detection apparatus of FIG. It is a figure which shows the example of arrangement | positioning of the detection coil of the foreign material detection apparatus of FIG. It is a figure which shows the example of wiring of the detection coil of FIG. It is a figure which shows the example of arrangement | positioning of the switching part of the foreign material detection apparatus of FIG. It is a figure which shows typically the structure of the switching part of FIG. (A) is a figure which shows the base and protective cover of the housing of the power transmission coil apparatus of FIG. 1, (b) is a figure which shows the state which attached the protective cover to the base correctly. (A) is a figure for demonstrating the detection coil of a normal state, (b) is a figure for demonstrating the detection coil of a disconnection state. (A) is a figure which shows the state in which the protective cover is closed normally, (b) is a figure which shows the state in which the protective cover is not closed normally. (A) is a figure for demonstrating the 1st foreign material detection process when a foreign material does not exist, (b) is a figure for demonstrating the 1st foreign material detection process when a foreign material exists. (A) is a figure for demonstrating the 2nd foreign material detection process when a foreign material does not exist, (b) is a figure for demonstrating the 2nd foreign material detection process when a foreign material exists. It is a flowchart which shows a series of processes which the foreign material detection apparatus of FIG. 2 performs. It is a flowchart which shows the failure diagnosis process of FIG. 13 in detail. It is a flowchart which shows the 1st foreign material detection process of FIG. 13 in detail. It is a flowchart which shows the 2nd foreign material detection process of FIG. 13 in detail. It is a figure which shows another example of arrangement | positioning of the detection coil of FIG. (A) is a figure which shows another form of the base and protective cover of the housing of the power transmission coil apparatus of FIG. 1, (b) is a figure which shows the state which attached the protective cover correctly to the base. It is a figure which shows another example of a connection of a detection coil and a switching part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

  FIG. 1 is a diagram illustrating an application example of a power transmission system and a foreign object detection device according to an embodiment. As shown in FIG. 1, the non-contact power supply system 1 includes a power transmission device 2 and a power reception device 3, and is a system for supplying power from the power transmission device 2 to the power reception device 3. The non-contact power supply system 1 is configured to supply electric power to an electric vehicle EV that has arrived at a parking lot or the like by using magnetic coupling between coils such as a magnetic resonance method or an electromagnetic induction method.

  The power transmission device 2 is a device that supplies power for non-contact power feeding. The power transmission device 2 generates desired AC power from a DC power source or an AC power source, and sends it to the power receiving device 3. The power transmission device 2 is installed on a road surface R such as a parking lot, for example. The power transmission device 2 includes a power transmission coil device 4 provided so as to protrude upward from a road surface R such as a parking lot. The power transmission coil device 4 has, for example, a flat frustum shape or a rectangular parallelepiped shape. The power transmission device 2 further includes a control unit 16 (see FIG. 2) and an inverter (not shown), and generates desired AC power from a DC power supply or an AC power supply. When the generated AC power is sent to the power transmission coil device 4, the power transmission coil device 4 generates magnetic flux.

  The power transmission coil device 4 includes a flat power transmission coil unit (not shown) that generates magnetic flux, and a housing 6 (housing) that houses the power transmission coil unit. The housing 6 has a flat frustum shape or a rectangular parallelepiped shape, for example, a base 61 fixed to the road surface R, and a protective cover 62 (cover) that defines the accommodation space V between the base 61 and the base 61. (See FIG. 3). The base 61 and the protective cover 62 are made of resin, for example. The base 61 may be realized by a nonmagnetic and conductive material (for example, aluminum).

  The power receiving device 3 is a device that receives power from the power transmitting device 2 and supplies power to a load (for example, a battery). The power receiving device 3 is mounted on, for example, an electric vehicle EV. The power receiving device 3 includes, for example, a power receiving coil device 5 attached to the bottom surface of a vehicle body (chassis or the like) of the electric vehicle EV. The power receiving coil device 5 is opposed to the power transmitting coil device 4 while being separated in the vertical direction during power supply. The power receiving coil device 5 has, for example, a flat frustum shape or a rectangular parallelepiped shape. The power receiving device 3 further includes a controller, a rectifier, and the like (both not shown). When the magnetic flux generated by the power transmission coil device 4 is linked to the power reception coil device 5, the power reception coil device 5 generates an induced current. Thereby, the receiving coil apparatus 5 receives the electric power from the power transmission coil apparatus 4 in non-contact. The electric power received by the receiving coil device 5 is supplied to a load (for example, a battery).

  The non-contact power supply system 1 further includes a foreign object detection device 10. The foreign object detection device 10 is a foreign object detection device for a coil device that is used for non-contact power feeding from the power transmission device 2, and is a device that detects foreign matter that has entered between the power transmission coil device 4 and the power receiving coil device 5. . The foreign matter to be detected is a conductive foreign matter, such as a coin and a steel nail. The foreign object detection device 10 is provided in the power transmission device 2, for example. Note that the power transmission system 7 is configured by the power transmission device 2 and the foreign object detection device 10.

  With reference to FIGS. 2-12, the power transmission system 7 and the foreign material detection apparatus 10 are demonstrated in detail. FIG. 2 is a diagram illustrating a functional configuration of the power transmission system 7. FIG. 3 is a diagram illustrating an arrangement example of each component of the foreign object detection device 10. FIG. 4 is a diagram illustrating an arrangement example of the detection coils. FIG. 5 is a diagram illustrating a wiring example of the detection coil. FIG. 6 is a diagram illustrating an arrangement example of the switching unit. FIG. 7 is a diagram schematically illustrating the configuration of the switching unit. FIG. 8A is a view showing a base and a protective cover of the housing of the power transmission coil device of FIG. 1, and FIG. 8B is a view showing a state where the protective cover is correctly attached to the base. FIG. 9A is a diagram for explaining a detection coil in a normal state, and FIG. 9B is a diagram for explaining a detection coil in a disconnected state. FIG. 10A is a diagram illustrating a state in which the protective cover is normally closed, and FIG. 10B is a diagram illustrating a state in which the protective cover is not normally closed. FIG. 11A is a diagram for explaining a first foreign object detection process when no foreign object exists, and FIG. 11B is a diagram for explaining a first foreign object detection process when a foreign object exists. is there. 12A is a diagram for explaining the second foreign object detection process when no foreign substance exists, and FIG. 12B is a diagram for explaining the second foreign object detection process when there is a foreign object. is there. 3 and 8, only one detection coil 11 is shown for convenience of explanation.

  As shown in FIGS. 2 and 3, the foreign object detection device 10 includes a plurality of detection coils 11, a switching unit 12, a measurement unit 13, a control unit 14, and a storage unit 15.

  The plurality of detection coils 11 are coils for detecting a foreign object, and include at least two detection coils (a first detection coil and a second detection coil). The detection coil 11 is disposed on the housing 6. The detection coil 11 is formed by a single conducting wire made of a conductive material, and a coil portion C is provided between a terminal A and a terminal B of the conducting wire. The coil part C only needs to have a shape capable of detecting a change in magnetic flux interlinking the coil part C, and is, for example, a one-turn (one turn) rectangular coil or an 8-shaped coil. The coil portion C is disposed in a state of being exposed on the surface 62 a of the protective cover 62. The detection coil 11 is disposed so as not to physically contact the other detection coils 11.

  As shown in FIG. 4, each of the coil portions C of the plurality of detection coils 11 has a surface so that the region surrounded by the coil portions C does not overlap the region surrounded by the coil portions C of the other detection coils 11. 62a. Each of the coil portions C of the plurality of detection coils 11 is separated from the coil portions C of the detection coils 11 adjacent to each other. The area of the region surrounded by the coil part C is determined according to the size of the foreign object to be detected. The distance between adjacent coil portions C is determined according to the size of the foreign object to be detected.

  In the example shown in FIG. 4, ten coil portions C1 to C10 are disposed on the surface 62a. The terminal A and the terminal B of the detection coil 11 are electrically connected to the first switching unit 21 and the second switching unit 22. As shown in FIG. 5A, the lead-out part D from the coil part C to the terminal A and the lead-out part E from the coil part C to the terminal B of the detection coil 11 extend along the side surface 62 c of the protective cover 62. Has been placed. Further, as shown in FIG. 5B, the lead-out portions D and E of the detection coil 11 may penetrate the protective cover 62 from the front surface 62a of the protective cover 62 toward the rear surface 62b. In this case, the protective cover 62 is provided with a through hole 62p, and the through hole 62p is subjected to conductive plating.

  The switching unit 12 is, for example, a selector. As shown in FIG. 6, the switching unit 12 is provided on the surface 61 a of the base 61. That is, the switching unit 12 is housed in the housing space V of the housing 6. Conductive wires 12a to 12t extend from the switching portion 12 to the periphery of the surface 61a, and a conductive pad P is provided at the tip of each conductive wire 12a to 12t. The conductive pad P is made of a conductive metal and has, for example, a rectangular shape. The switching unit 12 includes a first switching unit 21 and a second switching unit 22.

  As shown in FIG. 7, the first switching unit 21 includes a plurality of input terminals 21a to 21j, a plurality of input terminals 21k to 21t, an output terminal 21u, and an output terminal 21v. The input terminals 21a to 21t are connected to the conducting wires 12a to 12t, respectively. That is, each of the input terminals 21a to 21j corresponds to the terminals A1 to A10 of the plurality of detection coils 11, and the terminals A1 to A10 are connected to the input terminals 21a to 21j, respectively. Each of the input terminals 21k to 21t corresponds to the terminals B1 to B10 of the plurality of detection coils 11, and the terminals B1 to B10 are connected to the input terminals 21k to 21t, respectively. The arrangement of the input terminals 21a to 21t in FIG. 7 does not indicate a physical arrangement, but is changed from the arrangement of the conducting wires 12a to 12t in FIG. 6 for the sake of convenience in order to explain the function of the first switching unit 21. ing.

  In response to a first switching instruction from the control unit 14, the first switching unit 21 selects any one of the input terminals 21a to 21j and electrically connects it to the output terminal 21u. Any one of 21t is selected and electrically connected to the output terminal 21v. In other words, the first switching unit 21 selects any one of the terminals A1 to A10 of the plurality of detection coils 11 as the first terminal and electrically connects it to the output terminal 21u. Any one of the terminals B1 to B10 is selected as the second terminal and electrically connected to the output terminal 21v. In addition, the input terminal which is not selected in the 1st switching part 21 is an open state.

  The second switching unit 22 includes a plurality of input terminals 22a to 22j, a plurality of input terminals 22k to 22t, an output terminal 22u, and an output terminal 22v. The input terminals 22a to 22t are connected to the conducting wires 12a to 12t, respectively. That is, each of the input terminals 22a to 22j corresponds to the terminals A1 to A10 of the plurality of detection coils 11, and the terminals A1 to A10 are connected to the input terminals 22a to 22j, respectively. Each of the input terminals 22k to 22t corresponds to the terminals B1 to B10 of the plurality of detection coils 11, and the terminals B1 to B10 are connected to the input terminals 22k to 22t, respectively. Note that the arrangement of the input terminals 22a to 22t in FIG. 7 does not indicate a physical arrangement, but is changed from the arrangement of the conducting wires 12a to 12t in FIG. 6 for the sake of convenience in order to explain the function of the second switching unit 22. ing.

  In response to a second switching instruction from the control unit 14, the second switching unit 22 selects any one of the input terminals 22a to 22j and electrically connects it to the output terminal 22u. Any one of 22t is selected and electrically connected to the output terminal 22v. In other words, the second switching unit 22 selects any one of the terminals A1 to A10 of the plurality of detection coils 11 as the first terminal and electrically connects it to the output terminal 22u. Any one of the terminals B1 to B10 is selected as the second terminal and electrically connected to the output terminal 22v. In addition, the input terminal which is not selected in the 2nd switching part 22 is an open state.

  Of the input terminals 21a to 21t of the first switching unit 21 and the input terminals 22a to 22t of the second switching unit 22, the set of input terminals connected to the same terminal of the same detection coil 11 is the conductors 12a to 12t. Of these, they are connected to the same conductor. For example, the input terminal 21a and the input terminal 22a are connected to the terminal A1 of the first detection coil 11 via the conducting wire 12a. As shown in FIG. 8, the connection between the terminals A and B of each detection coil 11 and the corresponding conductors 12 a to 12 t is made through the conductive pads P. That is, when the protective cover 62 is attached to the base 61 at the correct position, the terminals A and B make contact with the conductive pads P provided at the tips of the corresponding conductive wires, respectively, and the corresponding input terminals 21a to 21t and It is electrically connected to the input terminals 22a to 22t.

  The measurement part 13 is measuring instruments, such as an ohmmeter, an ammeter, and a voltmeter, for example. The measurement unit 13 is provided below the road surface R, for example. The measurement unit 13 includes a first measurement unit 31 and a second measurement unit 32.

  The first measurement unit 31 includes a resistance value between the output terminal 21u and the output terminal 21v of the first switching unit 21, a current value flowing between the output terminal 21u and the output terminal 21v, or the output terminal 21u and the output terminal 21v. Measure the voltage value between. In response to the first measurement instruction from the control unit 14, the first measurement unit 31 supplies current between the output terminal 21 u and the output terminal 21 v to perform measurement. The first measurement unit 31 outputs the first measurement value to the control unit 14.

  The second measuring unit 32 has a resistance value between the output terminal 22u and the output terminal 22v of the second switching unit 22, a current value flowing between the output terminal 22u and the output terminal 22v, or the output terminal 22u and the output terminal 22v. Measure the voltage value between them (potential difference between terminals). The second measurement unit 32 performs measurement according to the second measurement instruction from the control unit 14. The second measurement unit 32 outputs the second measurement value to the control unit 14.

  The control unit 14 performs failure diagnosis processing, first foreign matter detection processing, and second foreign matter detection processing. The control unit 14 is a computer including a processor and a memory, for example. The control unit 14 is provided below the road surface R, for example. The control unit 14 includes a switching control unit 41, a failure determination unit 42, and a foreign object detection unit 43.

  The switching control unit 41 controls switching of the input terminal of the switching unit 12 connected to the output terminal of the switching unit 12. The switching control unit 41 outputs a first switching instruction to the first switching unit 21 and outputs a second switching instruction to the second switching unit 22. The switching control unit 41 outputs the first measurement instruction to the first measurement unit 31 after outputting the first switching instruction. The switching control unit 41 outputs the second measurement instruction to the second measurement unit 32 after outputting the second switching instruction.

  The failure determination unit 42 causes the first switching unit 21 to select the two terminals A and B of the same detection coil 11 as the first terminal and the second terminal, and the connection between the first terminal and the second terminal is short-circuited. It functions as a failure determination means for determining the presence or absence of a failure depending on whether the state is the open state or the open state. Specifically, the failure determination unit 42 performs failure diagnosis processing. The failure diagnosis processing is processing for determining whether or not the foreign object detection device 10 has failed. The failure determination unit 42 gives a first switching instruction to the switching control unit 41 so that the terminals A and B of the same detection coil 11 are connected to the output terminal 21u and the output terminal 21v of the first switching unit 21, respectively. Output. The failure determination unit 42 is in an open state (disconnected state) in which the terminals A and B of the detection coil 11 are electrically disconnected based on the first measurement value received from the first measurement unit 31. Or an open short circuit determination as to whether or not it is in a short circuit state (conductive state) that is an electrically connected state. The failure determination unit 42 performs open short circuit determination for all the detection coils 11. The order of the detection coils 11 in which the open / short circuit determination is performed is arbitrary.

  The open / short circuit determination is performed by comparing the first measured value with the first threshold value stored in the storage unit 15. The first threshold value is a current value, a voltage value, and a resistance value that are criteria for determining whether the terminal A and the terminal B of the detection coil 11 are in a short circuit state or an open state. When the first measurement value is a resistance value, if the first measurement value is greater than or equal to the first resistance threshold value, it is determined that the circuit is open, and if the first measurement value is less than the first resistance threshold value, the short circuit state is established. It is determined that there is. Since the current does not flow if the terminals are open, a very high resistance value is measured, and if the terminals are short-circuited, the resistance value of the conductive wire constituting the coil is measured. Low. When the first measurement value is a current value, if the first measurement value is equal to or greater than the first current threshold value, it is determined that the short circuit state is established. If the first measurement value is less than the first current threshold value, the open state is established. It is determined that there is. If the terminal is open, current does not flow, so a current value close to 0 is measured. If the terminal is short-circuited, current flows, so the current value corresponding to the amount of flow is measured. . When the first measurement value is a voltage value, if the first measurement value is greater than or equal to the first voltage threshold, it is determined to be in an open state, and if the first measurement value is less than the first voltage threshold, then in a short circuit state It is determined that there is. If the terminals are in an open state, the voltage value corresponding to the voltage applied to the terminals is measured. If the terminals are in a short circuit state, the resistance value of the coil conductor is low, so a voltage value close to 0 is measured. .

  As shown in FIG. 9A, when the conductor of the detection coil 11 is not disconnected, for example, the current supplied to the terminal A1 of the first detection coil 11 is output from the terminal B1. At this time, the current value measured by the first measuring unit 31 is equal to or greater than the first current threshold value, and the voltage value and the resistance value between the terminal A1 and the terminal B1 are smaller than the first voltage threshold value and the first resistance threshold value, respectively. . For this reason, the failure determination unit 42 determines that the terminal A1 and the terminal B1 of the detection coil 11 are in a short circuit state. The failure determination unit 42 determines that the terminals A and B are short-circuited in the same manner for the other detection coils 11 as well.

  As shown in FIG. 9B, for example, when the conducting wire of the first detection coil 11 is disconnected, the current supplied to the terminal A1 of the first detection coil 11 is not output from the terminal B1 or is small. The current of the current value is output. At this time, the current value measured by the first measuring unit 31 is smaller than the first current threshold value, and the voltage value and the resistance value between the terminal A1 and the terminal B1 are equal to or higher than the first voltage threshold value and the first resistance threshold value, respectively. Become. For this reason, the failure determination unit 42 determines that the terminal A1 and the terminal B1 of the first detection coil 11 are in an open state.

  As shown in FIG. 10A, when the protective cover 62 is attached to the correct position of the base 61 (when the protective cover 62 is properly closed), the terminals A and B of the detection coil 11 are used. Are in contact with the corresponding conductive pads P. In this state, for example, the current supplied to the input terminal of the first switching unit 21 to which the terminal A1 of the first detection coil 11 is connected is passed through the detection coil 11 to the terminal of the first detection coil 11. The signal is input to the input terminal of the first switching unit 21 to which B1 is connected. At this time, as in FIG. 9A, the current value measured by the first measurement unit 31 is equal to or greater than the first current threshold, and the voltage value and the resistance value between the terminal A1 and the terminal B1 are the first voltage, respectively. It becomes smaller than the threshold and the first resistance threshold. For this reason, the failure determination unit 42 determines that the terminal A1 and the terminal B1 of the detection coil 11 are in a short circuit state. The failure determination unit 42 determines that the terminals A and B are short-circuited in the same manner for the other detection coils 11 as well.

  As shown in FIG. 10 (b), when the protective cover 62 is attached with a deviation from the correct position of the base 61 (when the protective cover 62 is not properly closed), the terminals A and The terminals B do not make contact with the corresponding conductive pads P. In this state, for example, the current supplied to the input terminal of the first switching unit 21 to which the terminal A1 of the first detection coil 11 is connected is the first switch to which the terminal B1 of the first detection coil 11 is connected. A current having a small current value is input to the input terminal of the unit 21. At this time, as in FIG. 9B, the current value measured by the first measurement unit 31 is smaller than the first current threshold, and the voltage value and the resistance value between the terminal A1 and the terminal B1 are It becomes more than 1 voltage threshold value and 1st resistance threshold value. For this reason, the failure determination unit 42 determines that the terminal A1 and the terminal B1 of the detection coil 11 are in an open state. The failure determination unit 42 determines that the terminal A and the terminal B are in an open state for the other detection coils 11 as well.

  That is, in the failure determination unit 42, when the protective cover 62 is attached to the correct position of the base 61 and the conductor of the detection coil 11 is not broken, the terminal A and the terminal B of the detection coil 11 are in a short-circuit state. It is determined that The failure determination unit 42 determines that the terminal A and the terminal B of the detection coil 11 are in an open state when the protective cover 62 is attached so as to be displaced from the correct position of the base 61 or the conductor of the detection coil 11 is disconnected. It is determined that The failure determination unit 42 determines that the foreign object detection device 10 has not failed when it is determined that the terminals A and B of all the detection coils 11 are in a short-circuit state. If the failure determination unit 42 determines that at least one of the terminals A and B of the detection coil 11 is in an open state, the detection coil 11 is disconnected or the protective cover 62 is attached to the correct position of the base 61. Therefore, it is determined that the foreign object detection device 10 has failed. If the failure determination unit 42 determines that the foreign object detection device 10 has failed, the failure determination unit 42 controls the power transmission device 2 to prohibit power supply. The control of the power transmission device 2 is realized when the foreign object detection device 10 outputs a power supply prohibition instruction to the power transmission device 2.

  The foreign object detection unit 43 performs a first foreign object detection process and a second foreign object detection process. The first foreign object detection process is a foreign object detection process using open / short determination. In the foreign matter detection unit 43, for a combination of two different detection coils 11, the terminal A of one detection coil 11 and the terminal B of the other detection coil 11 are connected to the output terminal 21u and the output terminal 21v of the first switching unit 21, respectively. The switching control part 41 is made to output a 1st switching instruction | indication so that each may be connected. Based on the first measurement value received from the first measurement unit 31, the foreign object detection unit 43 determines whether the terminal A of one detection coil 11 and the terminal B of the other detection coil 11 are open or short-circuited. Open / short circuit judgment is performed. The foreign object detection unit 43 performs open / short-circuit determination for all combinations of two detection coils 11 that are different from each other among all the detection coils 11. The order of the combination of the detection coils 11 in which the open / short circuit determination is performed is arbitrary.

  As shown in FIG. 11A, when the foreign matter M is not present on the surface 62a of the protective cover 62, for example, in the combination of the first detection coil 11 and the second detection coil 11, the first detection is performed. The current supplied to the terminal A1 of the coil 11 is not output from the terminal B2 of the second detection coil 11. At this time, the current value measured by the first measurement unit 31 is smaller than the first current threshold value, and the voltage value and the resistance value between the terminal A1 and the terminal B2 are equal to or higher than the first voltage threshold value and the first resistance threshold value, respectively. Become. For this reason, the foreign object detection unit 43 determines that the terminal A1 of the first detection coil 11 and the terminal B2 of the second detection coil 11 are in an open state. Similarly, for the combination of the other two detection coils 11, the failure determination unit 42 determines that the terminal A of one detection coil 11 and the terminal B of the other detection coil 11 are open.

  As shown in FIG. 11B, the coil part C1 of the first detection coil 11, the coil part C2 of the second detection coil 11, the coil part C6 of the sixth detection coil 11, and the seventh detection coil. In the case where there is a foreign matter M in contact with the eleven coil portion C7, for example, in the combination of the first detection coil 11 and the second detection coil 11, it is supplied to the terminal A1 of the first detection coil 11. The current is output from the terminal B2 of the second detection coil 11 through the coil part C1, the foreign matter M, and the coil part C2 in this order. At this time, the current value measured by the first measuring unit 31 is equal to or greater than the first current threshold value, and the voltage value and the resistance value between the terminal A1 and the terminal B2 are smaller than the first voltage threshold value and the first resistance threshold value, respectively. . For this reason, the foreign object detection unit 43 determines that the terminal A1 of the first detection coil 11 and the terminal B2 of the second detection coil 11 are in a short-circuit state. The foreign matter M becomes a resistance when an electric current flows. Therefore, the short-circuit state due to the presence of the foreign matter M may cause an increase in resistance value, a decrease in current, and an increase in voltage (potential difference) as compared to a short-circuit state between terminals of the same coil where the foreign matter M does not exist. Accordingly, the first current threshold, the first voltage threshold, and the first resistance threshold are determined based on the assumed resistance value of the foreign matter M.

  When it is determined that the terminal A and the terminal B are in a short-circuited state in at least one of the combinations, the detection coil 11 of the combination is considered to be short-circuited by a foreign object, and thus the foreign object detection unit 43 includes a protective cover It is determined that foreign matter is present on the surface 62a of 62. When it is determined that the terminals A and B are open for all combinations of the detection coils 11, the foreign matter detection unit 43 detects foreign matter on the surface 62 a of the protective cover 62 by the first foreign matter detection process. Is determined not to exist.

  The second foreign object detection process is a foreign object detection process that uses a change in the amount of magnetic flux interlinking the coil portion C of the detection coil 11. During power feeding from the power transmission coil device 4 to the power reception coil device 5, magnetic flux is generated from the power transmission coil device 4. A part of this magnetic flux interlinks the coil portion C of the detection coil 11, whereby an induced voltage (induced electromotive force) and an induced current are generated between the terminal A and the terminal B of the detection coil 11. The induced voltage and the induced current change according to the amount of magnetic flux interlinking the coil part C. When conductive foreign matter exists in the region surrounded by the coil portion C, the amount of magnetic flux between the power transmission coil device 4 and the power receiving coil device 5 and the change of the magnetic flux path are caused by the material of the foreign matter. . For example, when the foreign material is a magnetic material (for example, iron), a magnetic flux is generated due to the spontaneous magnetization of the foreign material, or the magnetic flux path is changed due to the magnetic flux concentration on the foreign material. Thereby, the magnetic flux amount which links the coil part C may increase / decrease. Further, when the foreign matter is a non-magnetic material (for example, aluminum or copper), the magnetic flux path changes so as to bypass the foreign matter, so that the amount of magnetic flux interlinking the coil portion C may increase or decrease.

  The foreign object detection unit 43 instructs the power transmission device 2 to supply power to the power transmission coil device 4 for the second foreign object detection processing. The electric power supplied to the power transmission coil device 4 for the second foreign object detection process can be adjusted as appropriate according to the size of the foreign object to be detected. This power may be a power (for example, about 3.3 kW) at the time of non-contact power supply (at the time of normal power supply when there is no foreign object), or may be a smaller power (for example, about 100 W). . The foreign matter detection unit 43 outputs a second switching instruction to the switching control unit 41 so that the terminals A and B of the same detection coil 11 are connected to the output terminal 22u and the output terminal 22v of the second switching unit 22, respectively. Let The foreign object detection unit 43 determines whether or not the magnetic flux amount of the detection coil 11 has changed based on the second measurement value received from the second measurement unit 32. The foreign object detection unit 43 performs a magnetic flux amount change determination for all the detection coils 11. The order of the detection coils 11 in which the magnetic flux amount change determination is performed is arbitrary.

  In the magnetic flux amount change determination, the difference (absolute value) between the second measurement value and the second measurement value (reference measurement value) when no foreign matter is present is compared with the second threshold value stored in the storage unit 15. Is done by. The second threshold value is a current value and a voltage value that serve as a criterion for determining whether there is a foreign object in the region surrounded by the coil portion C or whether there is no foreign object. When the second measured value is a current value, if the difference between the second measured value and the reference measured value is equal to or greater than the second current threshold, it is determined that the amount of magnetic flux has changed, and the difference is less than the second current threshold. If there is, it is determined that the amount of magnetic flux has not changed. When the second measured value is a voltage value, if the difference between the second measured value and the reference measured value is greater than or equal to the second voltage threshold, it is determined that the amount of magnetic flux has changed, and the second measured value is the second voltage threshold. If less, it is determined that the amount of magnetic flux has not changed.

  As shown in FIG. 12A, when the foreign matter M is not present on the surface 62 a of the protective cover 62, for example, the amount of magnetic flux corresponding to the power supply from the power transmission coil device 4 is the coil portion of the second detection coil 11. Interlink C. At this time, the current value of the induced current flowing through the terminals A2 and B2 of the second detection coil 11, that is, the difference between the current value measured by the second measurement unit 32 and the reference measurement value is larger than the second current threshold value. The voltage value of the induced voltage generated at the terminals A2 and B2 of the second detection coil 11, that is, the difference between the voltage value measured by the second measurement unit 32 and the reference measurement value is smaller than the second voltage threshold. Get smaller. For this reason, the foreign matter detection unit 43 determines that the foreign matter M does not exist in the region surrounded by the coil portion C of the second detection coil 11. The foreign object detection unit 43 similarly determines that no foreign object M exists in the region surrounded by the coil part C of the detection coil 11 for the other detection coils 11.

  As shown in FIG. 12B, when the foreign matter M is present in the region surrounded by the coil portion C <b> 2 of the second detection coil 11, what is the amount of magnetic flux according to the power supply from the power transmission coil device 4? Different magnetic flux amounts interlink the coil portion C of the second detection coil 11. At this time, the difference between the current value of the induced current flowing through the terminals A2 and B2 of the second detection coil 11, that is, the current value measured by the second measurement unit 32 and the reference measurement value is equal to or greater than the second current threshold. The voltage value of the induced voltage generated at the terminal A2 and the terminal B2 of the second detection coil 11, that is, the difference between the voltage value measured by the second measurement unit 32 and the reference measurement value is equal to or greater than the second voltage threshold value. For this reason, the foreign matter detection unit 43 determines that the foreign matter M exists in the region surrounded by the coil portion C of the second detection coil 11.

  When it is determined that the amount of magnetic flux of at least one of the detection coils 11 has changed, it is considered that a foreign object exists in the region surrounded by the coil part C of the detection coil 11, and therefore the foreign object detection unit 43 is It is determined that foreign matter is present on the surface 62a of the protective cover 62. When it is determined that the amount of magnetic flux of all the detection coils 11 has not changed, the foreign matter detection unit 43 has no foreign matter that can be detected by the second foreign matter detection process on the surface 62a of the protective cover 62. judge.

  The foreign object detection unit 43 controls the power transmission device 2 to adjust the power supply when it is determined by the first foreign object detection process or the second foreign object detection process that a foreign object exists on the surface 62a of the protective cover 62. . The control of the power transmission device 2 is realized by the foreign matter detection unit 43 outputting a power supply adjustment instruction to the power transmission device 2. The power supply adjustment instruction is, for example, an instruction for prohibiting power supply for contactless power supply or an instruction for supplying lower power than that for normal contactless power supply. When the foreign matter detection unit 43 determines that no foreign matter is present on the surface 62a of the protective cover 62 in both the first foreign matter detection process and the second foreign matter detection process, the power transmission coil device is used for non-contact power feeding. The power transmission apparatus 2 is instructed to supply power to 4.

  The control unit 16 of the power transmission device 2 supplies power to the power reception device 3 via the power transmission coil device 4 in response to a power supply instruction from the foreign object detection unit 43. The control unit 16 prohibits power supply to the power receiving device 3 or supplies low power in response to a power supply prohibition instruction or power supply adjustment instruction from the failure determination unit 42 and the foreign object detection unit 43.

  Next, a series of processes performed by the foreign object detection device 10 will be described with reference to FIGS. FIG. 13 is a flowchart showing a series of processes performed by the foreign object detection device 10. FIG. 14 is a flowchart showing in detail the failure diagnosis process of FIG. FIG. 15 is a flowchart showing in detail the first foreign object detection process of FIG. FIG. 16 is a flowchart showing in detail the second foreign object detection process of FIG. The process illustrated in FIG. 13 is started in response to a power supply start instruction to the power transmission coil device 4, for example.

  First, the foreign object detection device 10 performs a failure diagnosis process (step S01). In the failure diagnosis process in step S01, as shown in FIG. 14, first, in the first switching unit 21, the input terminal connected to the terminal A of the same detection coil 11 and the input terminal connected to the terminal B are: The failure determination unit 42 causes the switching control unit 41 to output a first switching instruction so as to be connected to the output terminal 21u and the output terminal 21v, respectively. Then, in response to the first switching instruction from the switching control unit 41, the first switching unit 21 selects any one of the input terminals 21a to 21j and electrically connects it to the output terminal 21u for input. Any one of the terminals 21k to 21t is selected and electrically connected to the output terminal 21v (step S11).

  Then, the switching control unit 41 outputs the first measurement instruction to the first measuring unit 31 after outputting the first switching instruction. The first measurement unit 31 supplies current between the output terminal 21u and the output terminal 21v in response to the first measurement instruction from the switching control unit 41 (step S12), and between the output terminal 21u and the output terminal 21v. A current value flowing through the output terminal 21, a voltage value between the output terminal 21u and the output terminal 21v, or a resistance value between the output terminal 21u and the output terminal 21v is measured (step S13). Then, the first measurement unit 31 outputs the first measurement value to the control unit 14. Then, the failure determination unit 42 performs an open / short circuit determination as to whether the terminals A and B of the detection coil 11 are in an open state or a short circuit state based on the first measurement value received from the first measurement unit 31. Perform (step S14). The processes in steps S11 to S14 are repeated for all the detection coils 11 in order.

  And the failure determination part 42 determines whether the foreign material detection apparatus 10 is out of order based on the determination result of the open short circuit determination in step S14 (step S15). In step S15, when it is determined that at least one of the terminals A and B of the detection coil 11 is open, the detection coil 11 is disconnected or the protective cover 62 is attached to the correct position of the base 61. Therefore, the failure determination unit 42 determines that the foreign object detection device 10 has failed (step S15; failure present).

  Then, failure determination unit 42 outputs a power feeding prohibition instruction to power transmission device 2 (control unit 16) (step S16). Then, the power transmission device 2 prohibits power supply to the power reception device 3 in response to the power supply prohibition instruction from the failure determination unit 42, and the series of processes performed by the foreign object detection device 10 ends. On the other hand, when it is determined in step S15 that the terminals A and B of all the detection coils 11 are in a short-circuit state, the failure determination unit 42 determines that the foreign object detection device 10 has not failed (step S15; No failure), the process proceeds to step S02.

  Subsequently, the foreign object detection device 10 performs a first foreign object detection process (step S02). In the first foreign object detection process of step S02, as shown in FIG. 15, first, in the first switching unit 21, a combination of two different detection coils 11 is connected to the terminal A of one detection coil 11. The foreign matter detection unit 43 instructs the switching control unit 41 to perform the first switching so that the input terminal and the input terminal connected to the terminal B of the other detection coil 11 are connected to the output terminal 21u and the output terminal 21v, respectively. Output. Then, in response to the first switching instruction from the switching control unit 41, the first switching unit 21 selects any one of the input terminals 21a to 21j and electrically connects it to the output terminal 21u for input. Any one of the terminals 21k to 21t is selected and electrically connected to the output terminal 21v (step S21).

  Then, the switching control unit 41 outputs the first measurement instruction to the first measuring unit 31 after outputting the first switching instruction. Then, the first measurement unit 31 supplies current between the output terminal 21u and the output terminal 21v according to the first measurement instruction from the switching control unit 41 (step S22), and between the output terminal 21u and the output terminal 21v. The current value of the current flowing through the output terminal, the voltage value between the output terminal 21u and the output terminal 21v, or the resistance value between the output terminal 21u and the output terminal 21v are measured (step S23). Then, the first measurement unit 31 outputs the first measurement value to the control unit 14. And the foreign material detection part 43 is based on the 1st measurement value received from the 1st measurement part 31, and the terminal A of one detection coil 11 and the terminal B of the other detection coil 11 are an open state, or a short circuit state. An open / short circuit determination is performed (step S24). The process of the above step S21-step S24 is repeated in order about all the combinations of the mutually different two detection coils 11 among all the detection coils 11. FIG.

  And the foreign material detection part 43 determines whether the foreign material exists on the surface 62a of the protective cover 62 based on the determination result of the open short circuit determination in step S24 (step S25). If it is determined in step S25 that at least any combination of the terminals A and B is in a short-circuited state, it is considered that the detection coil 11 of the combination is short-circuited by the foreign matter, and therefore the foreign matter detection unit 43. Determines that there is foreign matter on the surface 62a of the protective cover 62 (step S25; foreign matter present).

  Then, the foreign object detection unit 43 outputs a power feeding adjustment instruction to the power transmission device 2 (control unit 16) (step S26). And the power transmission apparatus 2 prohibits the power feeding to the power receiving apparatus 3 according to the power feeding adjustment instruction from the foreign object detection unit 43, or the power feeding power to the power receiving apparatus 3 is lower than the power at the time of non-contact power feeding, A series of processes performed by the foreign object detection device 10 is completed. On the other hand, when it is determined in step S25 that the terminal A and the terminal B are open for all combinations of the detection coils 11, the foreign matter detection unit 43 detects the first foreign matter on the surface 62a of the protective cover 62. It is determined that there is no foreign matter that can be detected by the processing (step S25; no foreign matter), and the process proceeds to step S03.

  Subsequently, the foreign object detection device 10 performs a second foreign object detection process (step S03). In the second foreign object detection process of step S03, as shown in FIG. 16, first, the foreign object detection unit 43 first supplies power to the power transmission coil apparatus 4 for the second foreign object detection process (the control unit 16). ) Is instructed to supply power (step S31). Then, the power transmission device 2 supplies power to the power reception device 3 in response to a power supply instruction from the foreign object detection unit 43. At this time, the electric power supplied to the power transmission coil device 4 may be electric power at the time of non-contact electric power supply, or may be electric power smaller than that.

  In the second switching unit 22, the foreign matter detection unit 43 connects the input terminal connected to the terminal A of the same detection coil 11 and the input terminal connected to the terminal B to the output terminal 22u and the output terminal 22v, respectively. As described above, the switching control unit 41 is caused to output a second switching instruction. Then, the second switching unit 22 selects any one of the input terminals 22a to 22j and electrically connects to the output terminal 22u in response to the second switching instruction from the foreign object detection unit 43, and inputs Any one of the terminals 22k to 22t is selected and electrically connected to the output terminal 22v (step S32).

  Then, the switching control unit 41 outputs the second measurement instruction to the second measurement unit 32 after outputting the second switching instruction. Then, the second measuring unit 32 determines the current value of the current flowing between the output terminal 22u and the output terminal 22v or the voltage value between the output terminal 22u and the output terminal 22v in accordance with the second measurement instruction from the switching control unit 41. Is measured (step S33). Then, the second measurement unit 32 outputs the second measurement value to the control unit 14. Then, the foreign matter detection unit 43 determines whether or not the magnetic flux amount of the detection coil 11 has changed based on the second measurement value received from the second measurement unit 32 as compared to the magnetic flux amount when no foreign matter is present. An amount change determination is performed (step S34). The processes in steps S32 to S34 are repeated for all the detection coils 11 in order.

  And the foreign material detection part 43 determines whether the foreign material exists on the surface 62a of the protective cover 62 based on the determination result of magnetic flux amount change determination in step S34 (step S35). If it is determined in step S35 that the amount of magnetic flux of at least one of the detection coils 11 has changed, it is considered that there is a foreign object in the region surrounded by the coil portion C of the detection coil 11. The unit 43 determines that a foreign substance exists on the surface 62a of the protective cover 62 (step S35; foreign substance present).

  Then, the foreign object detection unit 43 outputs a power feeding adjustment instruction to the power transmission device 2 (control unit 16) (step S36). And the power transmission apparatus 2 prohibits the power feeding to the power receiving apparatus 3 according to the power feeding adjustment instruction from the foreign object detection unit 43, or the power feeding power to the power receiving apparatus 3 is lower than the power at the time of non-contact power feeding, A series of processes performed by the foreign object detection device 10 is completed. On the other hand, when it is determined in step S35 that the amount of magnetic flux of all the detection coils 11 has not changed, the foreign matter detection unit 43 detects foreign matter on the surface 62a of the protective cover 62 by the second foreign matter detection process. Is determined not to exist (step S35; no foreign matter), and the process proceeds to step S04.

  Subsequently, the foreign object detection device 10 outputs a power supply instruction to the power transmission device 2 (control unit 16) so as to start power supply to the power receiving device 3 for non-contact power supply (step S04). Then, the power transmission device 2 starts power supply to the power reception device 3 in response to a power supply instruction from the foreign object detection unit 43. At this time, the power transmission device 2 continues power feeding to the power receiving device 3 when power feeding at the time of non-contact power feeding is performed in step S03. In this way, a series of processes performed by the foreign object detection device 10 is completed. Note that a series of processing performed by the foreign object detection device 10 may be performed during non-contact power feeding. Further, step S03 may be performed before step S02, and step S02 and step S03 may be performed in parallel unless the same detection coil 11 is selected at the same time.

  As described above, in the foreign object detection device 10, the terminal A of one detection coil 11 and the terminal B of the other detection coil 11 are short-circuited with respect to a combination of two different detection coils 11 among the plurality of detection coils 11. The first foreign matter determination process is performed to determine the presence or absence of the conductive foreign matter depending on whether it is in the open state or the open state, and the conductive matter is determined according to the change in the amount of magnetic flux interlinking the same detection coil 11. Second foreign matter determination processing is performed in which the presence or absence of foreign matter is determined. When a conductive foreign substance exists in a region surrounded by one of the two different detection coils 11, the two detection coils 11 are not short-circuited. For this reason, such a foreign object cannot be detected in the first foreign object determination process. However, since the amount of magnetic flux interlinking the detection coil 11 surrounding the foreign matter changes from the amount of magnetic flux interlinking the detection coil 11 when no foreign matter is present, the foreign matter that is not in contact with the two or more detection coils 11 Even so, the foreign matter can be detected by the second foreign matter determination process. Further, when there is a foreign object in the dead zone, the amount of magnetic flux that links each of the detection coils 11 is substantially the same as the amount of magnetic flux that links each of the detection coils 11 when there is no foreign object. For this reason, such a foreign object cannot be detected in the second foreign object determination process. However, when a foreign object is in contact with two or more detection coils 11, the terminal A of one of the detection coils 11 and the terminal B of the other detection coil 11 are short-circuited. Therefore, the foreign matter can be detected by the first foreign matter determination process. As a result, the foreign object detection accuracy can be improved.

  When the terminals A and B of the same detection coil 11 are in an open state, it can be determined that a failure exists because the detection coil 11 is considered to be physically disconnected. When the detection coil 11 is disconnected, even if there is a foreign object in contact with the disconnected detection coil 11 and the other detection coil 11, the two detection coils 11 are in an open state. May be judged. For this reason, in the first foreign matter determination process, foreign matter detection may be missed. Further, when the detection coil 11 is disconnected, an induced current does not flow through the detection coil 11, so there is a possibility that a foreign object is erroneously detected in the second foreign object determination process. For example, when it is determined that the foreign object detection device 10 is out of order, the foreign object detection processing is not performed, thereby preventing erroneous detection and omission of foreign objects due to the detection coil 11 being disconnected. It becomes possible.

  When the protective cover 62 is correctly attached to the base 61, each terminal of the detection coil 11 is in contact with the conductive pad P and is electrically connected to one of the conductive wires 12a to 12t via the conductive pad P. The On the other hand, when the protective cover 62 is not correctly attached to the base 61, each terminal of the detection coil 11 does not make contact with the conductive pad P and is not electrically connected to the conducting wires 12a to 12t. For this reason, when the protective cover 62 is correctly attached to the base 61 and the detection coil 11 is not physically disconnected, the terminals A and B of the detection coil 11 are short-circuited. When the protective cover 62 is not correctly attached to the base 61 or when the detection coil 11 is physically disconnected, the terminals A and B of the detection coil 11 are opened. Therefore, when the terminals A and B of the same detection coil 11 are in an open state, the detection coil 11 is physically disconnected or the protective cover 62 is not correctly attached to the base 61. Since it is considered, it can be determined that the foreign object detection device 10 has failed. Thereby, for example, when it is determined that the foreign object detection device 10 has failed, the protective cover 62 is correctly attached to the base 61 by notifying the user that the protective cover 62 is not correctly attached. Can be encouraged. And by attaching (closing) the protective cover 62 to the correct position, dust and water can be prevented from entering the housing space V of the housing 6, and the failure of the power transmission coil device 4 due to the displacement of the protective cover 62 can be prevented. It becomes possible to suppress.

  Further, when the detection coil 11 is physically disconnected or the protective cover 62 is not correctly attached to the base 61, the foreign object detection device may not be able to detect the foreign object accurately. For this reason, when it is determined that there is a failure, the non-contact power supply in a state where foreign object detection cannot be normally performed can be suppressed by prohibiting the power supply for the non-contact power supply. Further, since the protective cover 62 is not correctly attached to the base 61, if dust, water, or the like enters the power transmission coil device 4 from the outside, the circuit in the power transmission coil device 4 may break down. For this reason, when it is determined that there is a failure, by prohibiting the power supply for contactless power supply, contactless power supply in a state where the circuit does not function normally can be suppressed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the number and shape of the detection coils 11 are not limited to the number and shape shown in FIG. The number of the detection coils 11 should just be at least two. The shape of the coil portion C of the detection coil 11 is not limited to a rectangular shape, and may be any shape that can capture magnetic flux. For example, the shape of the coil portion C of the detection coil 11 may be a polygonal shape such as an annular shape, a triangular shape, or a pentagonal shape. The coil portions C of the plurality of detection coils 11 may have different sizes and shapes.

  For example, as shown in FIG. 17, the coil portion C1 may be disposed near the center of the surface 62a of the protective cover 62, and the coil portion C2 may be disposed so as to surround the coil portion C1. Furthermore, each coil part C3-C9 may be arrange | positioned so that the coil part before the coil part may be enclosed in order of coil part C3-C9. That is, the coil part C9 is provided along the outer periphery of the surface 62a of the protective cover 62, and the coil part C8 that is slightly smaller is disposed in the area surrounded by the coil part C9, and further in the area surrounded by the coil part C8. Further, the coil portion C7 that is slightly smaller may be disposed, and thereafter, the coil portions C6 to C1 may be disposed in the order surrounded by the coil portion in front of the coil portion. Also, an arrangement combining the arrangement of FIG. 4 and the arrangement of FIG. 17 may be employed. The detection coil 11 may be disposed on the side surface 62 c of the protective cover 62. In addition, if the coil part C becomes large, the detection sensitivity of the foreign material by a 2nd foreign material detection process will fall. For this reason, the magnitude | size of the coil part C is defined according to the foreign material used as a detection target.

  The switching unit 12 includes the first switching unit 21 and the second switching unit 22, but may include one switching unit having the functions of the first switching unit 21 and the second switching unit 22. Further, the switching unit 12 is accommodated in the accommodating space V of the housing 6, but may be provided outside the housing 6. The measurement unit 13 includes the first measurement unit 31 and the second measurement unit 32, but may include one measurement unit having the functions of the first measurement unit 31 and the second measurement unit 32.

  Further, the shape of the conductive pad P may be circular. Further, the electrical connection between the terminals A and B of the detection coil 11 and the input terminal of the switching unit 12 is not limited to the configuration shown in FIG. For example, as shown in FIG. 18, the terminals A and B of the detection coil 11 may be conductive convex portions, and the conductive pads P provided at the tips of the conducting wires 12 a to 12 t of the switching portion 12 may be concave portions. When the protective cover 62 is attached to the correct position of the base 61, the convex portion and the concave portion are fitted to each other. Thereby, each terminal of the detection coil 11 is electrically connected to the conducting wires 12 a to 12 t of the switching unit 12. Furthermore, a thread groove may be provided in the convex part and the concave part. In this case, when the protective cover 62 is attached to the correct position of the base 61, the convex portion is screwed into the concave portion, so that each terminal of the detection coil 11 is electrically connected to the conducting wires 12a to 12t of the switching portion 12. May be.

  Further, the detection coil 11 and the switching unit 12 are connected via the conductive pad P. In addition, as shown in FIG. 19, the detection coil 11 and the switching unit 12 are respectively connected from the extraction part D and the extraction part E of the detection coil 11. You may connect by the branched conducting wire part 23. FIG. The switching unit 12 may connect each conducting wire unit 23 to a third switching unit different from the first switching unit 21 and the second switching unit 22, and the failure determination unit 42 uses the third switching unit to open-short circuit. A determination may be made. According to this configuration, the failure determination unit 42 can distinguish and determine whether or not the protective cover 62 is attached to the correct position of the base 61 and whether or not the conducting wire of the detection coil 11 is broken. . The failure determination unit 42 can determine that the foreign object detection device 10 has failed only when the detection coil 11 is disconnected.

  Further, the foreign object detection device 10 may not include the failure determination unit 42. That is, in the series of processes shown in FIG. 13, the failure diagnosis process in step S01 can be omitted.

  Moreover, although the foreign material detection apparatus 10 was demonstrated as providing the control part 14, this invention is not limited to this aspect. For example, the control unit 16 of the power transmission device 2 may have the same function as the control unit 14, and the control unit 16 of the power transmission device 2 may control the switching unit 12 of the foreign object detection device 10. And the control part 16 performs failure determination and foreign material detection, and controls the electric power feeding of the power transmission apparatus 2 based on the result of determination and detection. In this case, each process shown in FIG. 13 is realized by the power transmission system 7 including the foreign object detection device 10 and the power transmission device 2. Furthermore, instead of the power transmission device 2, the control unit of the power reception device 3 may have the same function as the control unit 14, and the control unit of the power reception device 3 may control the switching unit 12 of the foreign object detection device 10. The exchange of control signals between the power receiving device 3 and the foreign object detection device 10 is realized by connecting both devices with a signal line or providing a wireless communication device in both devices.

DESCRIPTION OF SYMBOLS 1 Non-contact electric power feeding system 2 Power transmission apparatus 3 Power receiving apparatus 4 Power transmission coil apparatus 5 Power receiving coil apparatus 6 Housing 7 Power transmission system 10 Foreign object detection apparatus 11 Detection coil 12 Switching part 13 Measurement part 14 Control part 16 Control part 16 Control part 21 1st switching part 22 1st 2 switching section 31 first measurement section 32 second measurement section 41 switching control section 42 failure determination section 43 foreign matter detection section 61 base 62 protective cover 62a surface A, A1-A10 terminal B, B1-B10 terminal C, C1-C10 coil Part

Claims (8)

A power transmission system comprising a power transmission device including a coil device used for non-contact power feeding and a foreign object detection device for the coil device,
A first detection coil and a second detection coil, each disposed on a housing of the coil device, each including two terminals;
One terminal of the first detection coil and one terminal of the second detection coil are selected as a first terminal, and the other terminal of the first detection coil and the other terminal of the second detection coil are selected. A switching unit for selecting one of the terminals as the second terminal;
Whether the terminals of the different detection coils are selected as the first terminal and the second terminal by the switching unit, and whether the connection between the first terminal and the second terminal is in a short-circuited state or an open state In response to the first foreign matter determination process for determining the presence or absence of conductive foreign matter, the switching unit selects the two terminals of the same detection coil as the first terminal and the second terminal, and the same A control unit for performing a second foreign matter determination process for determining the presence or absence of the foreign matter according to a change in the amount of magnetic flux interlinking the detection coil;
A power transmission system comprising:   The control unit further causes the switching unit to select two terminals of the same detection coil as the first terminal and the second terminal, and the connection between the first terminal and the second terminal is short-circuited. The power transmission system according to claim 1, wherein the presence or absence of a failure is determined according to whether it is in an open state. The housing includes a cover and a base that define a housing space for housing the coil device,
The switching unit includes a plurality of input terminals, and each of the plurality of input terminals corresponds to one of the terminals of the first detection coil and the second detection coil,
The first detection coil and the second detection coil are provided on the cover,
The power transmission system according to claim 2, wherein each terminal of the first detection coil and the second detection coil is electrically connected to a corresponding input terminal by attaching the cover to the base.   The power transmission system according to claim 2 or 3, wherein the control unit controls the power transmission device to prohibit power supply for non-contact power supply when it is determined that a failure exists.   When it is determined that the conductive foreign matter is present, the control unit prohibits power supply for non-contact power supply, or supplies power lower than that during non-contact power supply, The power transmission system according to any one of claims 1 to 4, wherein the power transmission device is controlled. The foreign object detection device includes the first detection coil, the second detection coil, and the switching unit.
The power transmission system according to any one of claims 1 to 5, wherein the power transmission device includes the control unit.   The power transmission system according to any one of claims 1 to 5, wherein the foreign object detection device includes the first detection coil, the second detection coil, the switching unit, and the control unit. A foreign matter detection device for a coil device used for non-contact power feeding from a power transmission device,
A first detection coil and a second detection coil, each disposed on a housing of the coil device, each including two terminals;
One terminal of the first detection coil and one terminal of the second detection coil are selected as a first terminal, and the other terminal of the first detection coil and the other terminal of the second detection coil are selected. A switching unit for selecting one of the terminals as the second terminal;
Whether the terminals of the different detection coils are selected as the first terminal and the second terminal by the switching unit, and whether the connection between the first terminal and the second terminal is in a short-circuited state or an open state In response to the first foreign matter determination process for determining the presence or absence of conductive foreign matter, the switching unit selects the two terminals of the same detection coil as the first terminal and the second terminal, and the same A control unit for performing a second foreign matter determination process for determining the presence or absence of the foreign matter according to a change in the amount of magnetic flux interlinking the detection coil;
A foreign object detection apparatus comprising:

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