JP6215969B2 - Wireless power transmission system and power transmission device and power reception device thereof - Google Patents

Description

The present invention relates to a wireless power transmission system, and more particularly to a wireless power transmission system compatible with a plurality of transmission methods. The present invention also relates to a power transmission device and a power reception device used in the wireless power transmission system.

  In recent years, a wireless power transmission system that wirelessly transmits power from a power transmission device to a power reception device by using magnetic field coupling between the power transmission coil and the power reception coil has been put into practical use.

  As a power transmission method using magnetic coupling (hereinafter, abbreviated as a transmission method), a power transmission coil and a power reception coil are placed close to each other, and electromagnetic power is transmitted from the power transmission device to the power reception device using the electromagnetic induction between the power transmission coil and the power reception coil. Magnetics that can transmit power from the power transmitting device to the power receiving device even when the distance between the power transmitting coil and the power receiving coil is long by using the electromagnetic induction method for transmitting the power and the magnetic resonance between the power transmitting coil and the power receiving coil A resonance method or the like is used.

  As a device related to an electromagnetic induction type conventional wireless power transmission system, a non-contact power transmission device (wireless power transmission system) as shown in Patent Document 1 has been proposed. FIG. 11 is an explanatory diagram showing a configuration of the non-contact power transmission apparatus 400 according to Patent Document 1.

  As illustrated in FIG. 11, the non-contact power transmission device 400 includes a primary circuit corresponding to the power transmission device and a secondary circuit corresponding to the power reception device. The circuit on the primary side includes a DC power supply 410, an inverter circuit 403 connected to the DC power supply 410, and a primary coil 405 a connected to the inverter circuit 403. The inverter circuit 403 includes capacitors 411, 412, 413, switching elements 414, 415 such as FETs, and diodes 414b, 415b.

  The secondary circuit includes a secondary coil 405b having a center tap, a rectifier circuit 421 connected to the secondary coil 405b, and a load 409 connected to the rectifier circuit 421. The rectifier circuit 421 includes a load matching capacitor 416, diodes 417 and 418, a current smoothing reactor 419, and a smoothing capacitor 240.

  The inverter circuit 403 generates an AC electrical signal for power transmission. The electric signal generated by the inverter circuit 403 is applied to the primary coil 405a. The primary coil 405a and the secondary coil 405b constitute a separable and detachable transformer 405. When the primary coil 405a and the secondary coil 405b are brought close to each other, electromagnetic waves are generated between the primary coil 405a and the secondary coil 405b. Induction occurs. Then, the AC electrical signal applied to the primary coil 405a is transmitted to the secondary coil 405b using electromagnetic induction between the primary coil 405a and the secondary coil 405b. The electric signal transmitted to the secondary coil 405b is converted into a DC electric signal via the rectifier circuit 421 and then output to the load 409.

  In this way, the non-contact power transmission device 400 uses the electromagnetic induction of the primary coil 405a and the secondary coil 405b to transmit power from the primary side circuit to the secondary side circuit in a non-contact (wireless) manner. ing.

  As a conventional wireless power transmission system of the magnetic resonance system, a non-contact power feeding system (wireless power transmission system) according to Patent Document 2 has been proposed. FIG. 12 is an explanatory diagram showing a configuration of a non-contact power feeding system 500 according to Patent Document 2. As shown in FIG.

  As illustrated in FIG. 12, the non-contact power supply system 500 includes a power supply facility 501 (power transmission device) and a power reception device 502. The power supply facility 501 includes a high frequency power supply device 510, a primary coil 520, a primary self-resonant coil 530, and a control device 540. The high frequency power supply device 510 generates a predetermined high frequency voltage based on a drive signal received from the control device 540 and supplies high frequency power for power transmission. Primary coil 520 transmits high-frequency power supplied from high-frequency power supply device 510 to primary self-resonant coil 530. Primary self-resonant coil 530 is an LC resonant coil for power transmission. C1 is the stray capacitance of the primary self-resonant coil 530.

  The power receiving device 502 includes a secondary self-resonant coil 560 and a secondary coil 570. Secondary self-resonant coil 560 is an LC resonant coil for receiving power. C2 is the stray capacitance of the secondary self-resonant coil 560. Secondary coil 570 extracts the power received by secondary self-resonant coil 560 and outputs the extracted power to load 503.

  Then, the non-contact power supply system 500 uses the resonance (magnetic resonance) via the electromagnetic field generated between the primary self-resonant coil 530 and the secondary self-resonant coil 560 to transfer power from the power supply facility 501 to the power receiving device 502. Power is transmitted by contact (wireless).

JP 2002-101578 A JP 2010-193598 A

  In recent years, there has been an increasing need for a wireless power transmission system that supports both the electromagnetic induction method and the magnetic resonance method. That is, regardless of whether the power receiving apparatus is an electromagnetic induction system or a magnetic resonance system, the wireless power transmission system that can transmit power from the power transmitting apparatus to the power receiving apparatus or the power transmitting apparatus There is a demand for practical use of a wireless power transmission system capable of transmitting power from a power transmission device to a power reception device, regardless of whether the transmission method is an induction method or a magnetic resonance method.

  In recent years, a plurality of transmission systems having different transmission frequencies and the like have been proposed in the electromagnetic induction system, and needs for wireless power transmission systems corresponding to these transmission systems are increasing. Similarly, in the magnetic resonance system, a plurality of transmission systems having different transmission frequencies and the like have been proposed, and needs for wireless power transmission systems corresponding to these transmission systems are increasing.

  Although the technique regarding the wireless power transmission system corresponding to two different transmission systems is not disclosed in Patent Documents 1 and 2, for example, on the power transmission device side, electric signals for power transmission corresponding to the respective transmission systems are disclosed. Can be applied to the two power transmission coils. However, in such a method, when two power transmission coils are arranged close to each other, unnecessary magnetic field coupling is generated between the two power transmission coils. And by the magnetic field coupling between two power transmission coils, the electric signal transmitted from one power transmission coil of the two power transmission coils is also transmitted to the other power transmission coil, and accordingly, the power transmission device receives power from the power transmission device. There is a possibility that the transmission efficiency (power transmission efficiency when transmitting power from the power transmission device to the power reception device) will be reduced.

Also, on the power receiving device side, a method of arranging two power receiving coils corresponding to each transmission method and receiving an electric signal corresponding to each transmission method is conceivable. However, in such a method, when two power receiving coils are arranged close to each other, magnetic field coupling occurs between the two power receiving coils. Then, due to magnetic field coupling between the two power receiving coils, a part of the electric signal received by one power receiving coil of the two power receiving coils is transmitted to the other power receiving coil, and accordingly, the power receiving device receives power from the power transmitting device. There is a possibility that the transmission efficiency to the apparatus is lowered.

The present invention has been made in view of the situation of the prior art as described above, and an object thereof is wireless power transmission capable of supporting two transmission methods and suppressing reduction in transmission efficiency from the power transmission apparatus to the power reception apparatus. A system and its power transmission device and power reception device are provided.

In order to solve this problem, a wireless power transmission system according to claim 1 includes a power transmission device having a power transmission coil and a power reception device having a power reception coil, and magnetic field coupling between the power transmission coil and the power reception coil. A wireless power transmission system that wirelessly transmits power from the power transmission device to the power reception device, wherein the power transmission device includes a first power transmission circuit corresponding to a first transmission method, and a second transmission. A second power transmission circuit corresponding to the system, a first power transmission coil corresponding to the first transmission system, a second power transmission coil corresponding to the second transmission system, the first power transmission circuit, and the first power transmission. Controlling a first switch element that switches a connection state with a coil, a second switch element that switches a connection state between the second power transmission circuit and the second power transmission coil, and the first switch element and the second switch element A control unit that, the, the first transmitting coil is a coil that corresponds to the wireless power transmission of electromagnetic induction type which is the first transmission method, the second power transmission coil transmitting the second The coil is compatible with magnetic resonance wireless power transmission, which is a system, and the control unit is configured to connect the second power transmission circuit and the second power transmission circuit when the first power transmission circuit and the first power transmission coil are in a connected state. When the power transmission coil is disconnected and the second power transmission circuit and the second power transmission coil are connected, the first power transmission circuit and the first power transmission coil are disconnected. The first switch element and the second switch element are controlled. A power transmission device according to a seventh aspect is a power transmission device used in the wireless power transmission system.

  In the wireless power transmission system having this configuration, the power transmission device includes a first power transmission circuit corresponding to the first transmission method, a second power transmission circuit corresponding to the second transmission method, and a first power transmission circuit corresponding to the first transmission method. 1 power transmission coil and a second power transmission coil corresponding to the second transmission system. Therefore, power can be transmitted from the power transmission apparatus to the power reception apparatus, regardless of which of the two transmission systems the power reception apparatus is.

  Moreover, when the first power transmission circuit and the first power transmission coil are in a connected state, the second power transmission circuit and the second power transmission coil are in a disconnected state, and the second power transmission circuit and the second power transmission coil are in a connected state. Sometimes, the first power transmission circuit and the first power transmission coil are disconnected. Therefore, even if the electric signal applied to the first power transmission coil is transmitted to the second power transmission coil due to the magnetic field coupling between the first power transmission coil and the second power transmission coil, the second power transmission coil and the second power transmission circuit are not connected. By setting the connection state, it is possible to prevent unnecessary current from flowing through the second power transmission circuit. In addition, even when an electric signal applied to the second power transmission coil is transmitted to the first power transmission coil due to magnetic field coupling between the first power transmission coil and the second power transmission coil, the first power transmission coil and the first power transmission circuit are not connected. By setting it as a connection state, it can prevent that an unnecessary electric current flows into a 1st power transmission circuit. As a result, power loss on the power transmission device side can be suppressed, and a decrease in transmission efficiency from the power transmission device to the power reception device can be suppressed.

The electromagnetic induction method is a transmission method that transmits power by bringing a power transmission coil and a power reception coil close to each other. The magnetic resonance method transmits power even when the distance between the power transmission coil and the power reception coil is long. This is a transmission method capable of Therefore, even when the power transmission device and the power reception device are close to each other or when the distance between the power transmission device and the power reception device is large, power can be transmitted from the power transmission device to the power reception device. As a result, the degree of freedom with respect to the distance between the power transmission device and the power reception device can be expanded.

In the wireless power transmission system according to claim 2 , a coil diameter of one coil of the first power transmission coil and the second power transmission coil is larger than a coil diameter of the other coil, and the one coil is In the plan view, the coil is disposed so as to surround the other coil.

  In the wireless power transmission system having this configuration, the coil diameter of one coil of the first power transmission coil and the second power transmission coil is larger than the coil diameter of the other coil. It arrange | positions so that the circumference | surroundings of a coil may be enclosed. Therefore, the space inside one coil can be effectively used, and the power transmission device can be reduced in size.

The wireless power transmission system according to claim 3 , wherein the power transmission device has a power feeding surface on which the power receiving device is placed, and the first power transmission coil and the second power transmission coil are on the back surface of the power feeding surface. The coil diameter of the second power transmission coil is larger than the coil diameter of the first power transmission coil.

  In the wireless power transmission system having this configuration, the power transmission device has a power feeding surface on which the power receiving device is placed, and the first power transmission coil and the second power transmission coil are disposed on the back side of the power feeding surface. Therefore, it is easy to stabilize the distance between the power transmission coil and the power reception coil, and power can be stably transmitted from the power transmission device to the power reception device. Moreover, in the wireless power transmission system with this configuration, the second power transmission coil is a coil that supports magnetic resonance wireless power transmission, and the coil diameter of the second power transmission coil is larger than the coil diameter of the first power transmission coil. Is also big. In the magnetic resonance wireless power transmission, the transmission distance (distance where the power can be effectively transmitted) can be increased as the outer diameter of the power transmission coil is increased. Therefore, even when the power receiving device is separated from the power feeding surface, it is easy to maintain power transmission from the power transmitting device to the power receiving device.

The wireless power transmission system according to claim 4 , comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and utilizing the magnetic field coupling between the power transmission coil and the power reception coil. A wireless power transmission system that wirelessly transmits power to the power receiving device, wherein the power transmission device includes a first power transmission circuit corresponding to a first transmission method and a second power transmission circuit corresponding to a second transmission method. And a switch for switching a connection state between the first power transmission coil corresponding to the first transmission method, the second power transmission coil corresponding to the second transmission method, and the first power transmission circuit and the first power transmission coil. And a control unit that controls the switch element, wherein the first power transmission coil is a coil corresponding to electromagnetic induction wireless power transmission that is the first transmission method, and the second power transmission. coil The a second coil corresponding to the wireless power transmission of the magnetic resonance method is a transmission method, the coil diameter of the second transmission coil is greater than the coil diameter of the first transmission coil, the second power transmitting coil Is arranged so as to surround the first power transmission coil in a plan view, and when the control unit applies an electric signal for power transmission to the first power transmission coil, the first power transmission circuit and the first power transmission The switch element is controlled so that the first power transmission circuit and the first power transmission coil are disconnected when the coil is connected and an electric signal for power transmission is applied to the second power transmission coil. It is characterized by that. A power transmission device according to an eighth aspect is a power transmission device used in the wireless power transmission system.

  In the wireless power transmission system having this configuration, the power transmission device includes a first power transmission circuit corresponding to the first transmission method, a second power transmission circuit corresponding to the second transmission method, and a first power transmission circuit corresponding to the first transmission method. 1 power transmission coil and a second power transmission coil corresponding to the second transmission system. Therefore, power can be transmitted from the power transmission apparatus to the power reception apparatus, regardless of which of the two transmission systems the power reception apparatus is.

  In addition, when the electrical signal for power transmission is applied to the first power transmission coil, the first power transmission circuit and the first power transmission coil are connected, and when the electrical signal for power transmission is applied to the second power transmission coil, the first power transmission is performed. The circuit and the first power transmission coil are disconnected. Therefore, even if the electric signal applied to the second power transmission coil is transmitted to the first power transmission coil by the magnetic field coupling between the first power transmission coil and the second power transmission coil, the first power transmission coil and the first power transmission circuit are not connected. By setting it as a connection state, it can prevent that an unnecessary electric current flows into a 1st power transmission circuit.

  Moreover, the coil diameter of the 2nd power transmission coil is larger than the coil diameter of the 1st power transmission coil, and the 2nd power transmission coil is arrange | positioned so that the circumference | surroundings of the 1st power transmission coil may be enclosed in planar view. Therefore, compared with the magnetic field coupling of the 1st power transmission coil and the 2nd power transmission coil by the magnetic flux which the 2nd power transmission coil generated, the 1st power transmission coil and the 2nd power transmission coil by the magnetic flux which the 1st power transmission coil generated The magnetic field coupling can be weakened. And it can suppress that the electric signal applied to the 1st power transmission coil is transmitted to the 2nd power transmission coil. As a result, power loss on the power transmission device side can be suppressed, and a decrease in transmission efficiency from the power transmission device to the power reception device can be suppressed.

The electromagnetic induction method is a transmission method that transmits power by bringing a power transmission coil and a power reception coil close to each other. The magnetic resonance method transmits power even when the distance between the power transmission coil and the power reception coil is long. This is a transmission method capable of Therefore, even when the power transmission device and the power reception device are close to each other or when the distance between the power transmission device and the power reception device is large, power can be transmitted from the power transmission device to the power reception device. As a result, the degree of freedom with respect to the distance between the power transmission device and the power reception device can be expanded.

The wireless power transmission system according to claim 5 , comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and utilizing the magnetic field coupling between the power transmission coil and the power reception coil. A wireless power transmission system that wirelessly transmits power to the power receiving device, wherein the power receiving device includes a first power receiving coil corresponding to a first transmission method and a second power receiving coil corresponding to a second transmission method. And a first power receiving circuit corresponding to the first transmission method, a second power receiving circuit corresponding to the second transmission method, and a first switching circuit for switching a connection state between the first power receiving coil and the first power receiving circuit. A third switch element, a fourth switch element that switches a connection state between the second power receiving coil and the second power receiving circuit, and a control unit that controls the third switch element and the fourth switch element. , before The first power receiving coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission method, and the second power receiving coil is the magnetic resonance wireless power transmission that is the second transmission method. a coil corresponding to said control unit, wherein when the first power receiving coil and the first power-receiving circuit is in the connected state, and the second receiving coil and the second power-receiving circuit is disconnected, the The third switch element and the fourth switch element are arranged such that when the second power receiving coil and the second power receiving circuit are connected, the first power receiving coil and the first power receiving circuit are disconnected. It is characterized by controlling. A power receiving device according to claim 9 is a power receiving device used in the wireless power transmission system.

  In the wireless power transmission system configured as described above, the power receiving device includes a first power receiving coil corresponding to the first transmission method, a second power receiving coil corresponding to the second transmission method, and a first power receiving device corresponding to the first transmission method. 1 power receiving circuit and a second power receiving circuit corresponding to the second transmission method. Therefore, power can be transmitted from the power transmission device to the power receiving device, regardless of which of the two transmission methods the power transmission device is.

  Moreover, when the first power receiving coil and the first power receiving circuit are connected, the second power receiving coil and the second power receiving circuit are disconnected, and the second power receiving coil and the second power receiving circuit are connected. Sometimes, the first power receiving coil and the first power receiving circuit are disconnected. Therefore, even if a part of the electric signal transmitted from the power transmission coil to the first power receiving coil is transmitted to the second power receiving coil due to the magnetic field coupling between the first power receiving coil and the second power receiving coil, the second power receiving coil and the second power receiving coil By making the second power receiving circuit non-connected, it is possible to prevent unnecessary current from flowing through the second power receiving circuit. Further, even if a part of the electrical signal transmitted from the power transmission coil to the second power receiving coil is transmitted to the first power receiving coil due to the magnetic field coupling between the first power receiving coil and the second power receiving coil, the first power receiving coil and the second power receiving coil By setting the one power receiving circuit in a disconnected state, it is possible to prevent an unnecessary current from flowing through the first power receiving circuit. As a result, power loss on the power receiving device side can be suppressed, and a decrease in transmission efficiency from the power transmitting device to the power receiving device can be suppressed.

The wireless power transmission system according to claim 6 , comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and utilizing the magnetic field coupling between the power transmission coil and the power reception coil. A wireless power transmission system that wirelessly transmits power to the power receiving device, wherein the power receiving device includes a first power receiving coil corresponding to a first transmission method and a second power receiving coil corresponding to a second transmission method. And a switch for switching a connection state between the first power receiving circuit corresponding to the first transmission method, the second power receiving circuit corresponding to the second transmission method, and the first power receiving coil and the first power receiving circuit. An element and a control unit that controls the switch element, wherein the first power receiving coil is a coil corresponding to electromagnetic induction wireless power transmission that is the first transmission method, and the second power receiving coil. coil The a coil corresponding to the wireless power transmission of the magnetic resonance method is the second transmission scheme, the coil diameter of the second receiving coil is larger than the coil diameter of the first receiving coil, the second power-receiving coil Is arranged so as to surround the periphery of the first power receiving coil in plan view, and the control unit transmits the electrical signal from the power transmitting coil to the first power receiving coil. When the power receiving coil is in a connected state and an electric signal is transmitted from the power transmitting coil to the second power receiving coil, the switch element is arranged so that the first power receiving circuit and the first power receiving coil are in a disconnected state. It is characterized by controlling. A power receiving device according to claim 10 is a power receiving device used in the wireless power transmission system.

  In the wireless power transmission system configured as described above, the power receiving device includes a first power receiving coil corresponding to the first transmission method, a second power receiving coil corresponding to the second transmission method, and a first power receiving device corresponding to the first transmission method. 1 power receiving circuit and a second power receiving circuit corresponding to the second transmission method. Therefore, power can be transmitted from the power transmission device to the power receiving device, regardless of which of the two transmission methods the power transmission device is.

  In addition, when the electric signal is transmitted from the power transmission coil to the first power receiving coil, the first power receiving circuit and the first power receiving coil are connected, and when the electric signal is transmitted from the power transmitting coil to the second power receiving coil, the first power receiving is received. The circuit and the first power receiving coil are connected. Therefore, even if a part of the electrical signal transmitted from the power transmission coil 12 to the second power receiving coil is transmitted to the first power receiving coil by the magnetic field coupling between the first power receiving coil and the second power receiving coil, By setting the first power receiving circuit in a disconnected state, it is possible to prevent unnecessary current from flowing through the first power receiving circuit.

  Moreover, the coil diameter of the 2nd receiving coil is larger than the coil diameter of the 1st receiving coil, and the 2nd receiving coil is arrange | positioned so that the circumference | surroundings of the 1st receiving coil may be enclosed in planar view. Therefore, compared with the magnetic coupling of the 1st receiving coil and the 2nd receiving coil by the magnetic flux which the 2nd receiving coil generated, the 1st receiving coil and the 2nd receiving power by the magnetic flux which the 1st receiving coil generated The magnetic field coupling with the coil can be weakened. And it can suppress that a part of electric signal transmitted to the 1st receiving coil is transmitted to the 2nd receiving coil. As a result, power loss on the power receiving device side can be suppressed, and a decrease in transmission efficiency from the power transmitting device to the power receiving device can be suppressed.

ADVANTAGE OF THE INVENTION According to this invention, the wireless power transmission system which can respond to two transmission systems, and can suppress the fall of the transmission efficiency from a power transmission apparatus to a power receiving apparatus, its power transmission apparatus, and a power receiving apparatus can be provided.

1 is a block diagram illustrating a configuration of a wireless power transmission system 1 according to a first embodiment of the present invention. It is explanatory drawing which shows the structure of the power transmission apparatus 10 shown in FIG. It is explanatory drawing which shows the connection state of the power transmission apparatus 10 shown in FIG. It is explanatory drawing which shows distribution of the magnetic flux which the power transmission coil 12 shown in FIG. 1 generate | occur | produced. It is a block diagram which shows the structure of the wireless power transmission system 101 which concerns on 2nd Embodiment of this invention. It is explanatory drawing which shows the switching method of the connection state of the power transmission apparatus 110 shown in FIG. It is a block diagram which shows the structure of the wireless power transmission system 201 which concerns on 3rd Embodiment of this invention. It is explanatory drawing which shows the switching method of the connection state of the power receiving apparatus 220 shown in FIG. It is a block diagram which shows the structure of the wireless power transmission system 301 which concerns on 4th Embodiment of this invention. It is explanatory drawing which shows the switching method of the connection state of the power receiving apparatus 320 shown in FIG. It is explanatory drawing which shows the structure of the non-contact electric power transmission apparatus 400 which concerns on patent document 1. It is explanatory drawing which shows the structure of the non-contact electric power feeding system 500 which concerns on patent document 2. FIG.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In each drawing, the description will be made with the X1 direction as the left direction, the X2 direction as the right direction, the Y1 direction as the front, the Y2 direction as the rear, the Z1 direction as the upper side, and the Z2 direction as the lower side.

  First, the configuration of the wireless power transmission system 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a block diagram showing a configuration of a wireless power transmission system 1 according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating a structure of the power transmission device 10 illustrated in FIG. 1. Fig.2 (a) is a schematic diagram which shows the structure at the time of seeing the power transmission apparatus 10 from the top. In FIG. 2A, the cover 16 is omitted for easy understanding of the internal structure. FIG. 2B is a schematic diagram showing the structure of the A1-A1 cross section of FIG. FIG. 3 is an explanatory diagram illustrating a connection state of the power transmission device 10 illustrated in FIG. 1. FIG. 3A shows a connection state when power transmission corresponding to the electromagnetic induction method is performed. FIG. 3B shows a connection state when power transmission corresponding to the magnetic resonance method is performed.

  As shown in FIG. 1, the wireless power transmission system 1 includes a power transmission device 10 and a power reception device 20. The wireless power transmission system 1 is a wireless power transmission system that supports both the electromagnetic induction method (first transmission method) and the magnetic resonance method (second transmission method). The electromagnetic induction method is a transmission method in which a power transmission coil and a power reception coil are brought close to each other, and electric power is transmitted from the power transmission device to the power reception device using electromagnetic induction between the power transmission coil and the power reception coil. The magnetic resonance method is a transmission method capable of transmitting electric power from the power transmission apparatus to the power reception apparatus using the magnetic resonance between the power transmission coil and the power reception coil even if the distance between the power transmission coil and the power reception coil is long. .

  The power transmission device 10 is a power transmission device that supports both the electromagnetic induction method and the magnetic resonance method. As shown in FIG. 1, the power transmission device 10 includes two power transmission circuits 11, two power transmission coils 12, two switch elements 13, and a control circuit 14 (control unit) that controls the two switch elements 13, have. The two power transmission circuits 11 are a first power transmission circuit 11a and a second power transmission circuit 11b. The two power transmission coils 12 are a first power transmission coil 12a and a second power transmission coil 12b. The two switch elements 13 are a first switch element 13a and a second switch element 13b. As shown in FIG. 2, the power transmission device 10 includes a case 15 for housing various circuits of the power transmission device 10 and the power transmission coil 12, and a cover 16 fixed to the upper side of the case 15. .

  The first power transmission circuit 11a generates an electric signal for power transmission corresponding to the electromagnetic induction method. As an electrical signal corresponding to the electromagnetic induction method, an alternating electrical signal having a frequency in the vicinity of several tens of kHz to several hundreds of kHz is usually used. A circuit such as an inverter circuit is used as the first power transmission circuit 11a.

  The second power transmission circuit 11b generates an electric signal for power transmission corresponding to the magnetic resonance method. As an electrical signal corresponding to the magnetic resonance system, an alternating electrical signal having a frequency in the vicinity of several MHz to several tens of MHz is usually used. A circuit such as an inverter circuit is used as the second power transmission circuit 11b.

  As shown in FIG. 2, the first power transmission coil 12 a is a spiral coil wound around the outer periphery of a circle. The first power transmission coil 12a corresponds to an electromagnetic induction method. Both ends of the first power transmission coil 12a are connected to the first power transmission circuit 11a via the first switch element 13a and a wiring (not shown). Then, the electric signal generated by the first power transmission circuit 11a is applied to the first power transmission coil 12a. The first power transmission coil 12a is formed by winding a conductive wire made of metal into a predetermined shape.

  The 2nd power transmission coil 12b is also a spiral coil wound along the outer periphery of the circle as shown in FIG. The second power transmission coil 12b corresponds to the magnetic resonance method. The coil diameter of the second power transmission coil 12b is set larger than the coil diameter of the first power transmission coil 12a. And the 2nd power transmission coil 12b is arrange | positioned so that the circumference | surroundings of the 1st power transmission coil 12a may be surrounded seeing from the top. Further, the second power transmission coil 12b resonates at a predetermined frequency due to its own inductance and stray capacitance.

  Both ends of the second power transmission coil 12b are connected to the second power transmission circuit 11b via the second switch element 13b and a wiring (not shown). Then, the electrical signal generated by the second power transmission circuit 11b is applied to the second power transmission coil 12b. The second power transmission coil 12b is formed by winding a conductive wire made of metal into a predetermined shape.

  The first switch element 13a switches the connection state between the first power transmission circuit 11a and the first power transmission coil 12a. When the first switch element 13a is turned on, the first power transmission circuit 11a and the both ends of the first power transmission coil 12a are electrically connected, and when the first switch element 13a is turned off. The electrical connection between the first power transmission circuit 11a and both ends of the first power transmission coil 12a is disconnected.

  Hereinafter, the state where the first power transmission circuit 11a and both ends of the first power transmission coil 12a are electrically connected is abbreviated as the connection state between the first power transmission circuit 11a and the first power transmission coil 12a. . In addition, the first power transmission circuit 11a and the first power transmission coil 12a are in a disconnected state that the electrical connection between the first power transmission circuit 11a and the both ends of the first power transmission coil 12a is disconnected. Abbreviated. As the first switch element 13a, a switching semiconductor such as an FET is used.

  The second switch element 13b switches the connection state between the second power transmission circuit 11b and the second power transmission coil 12b. When the second switch element 13b is turned on, the second power transmission circuit 11b and the both ends of the second power transmission coil 12b are electrically connected, and when the second switch element 13b is turned off. The electrical connection between the second power transmission circuit 11b and both ends of the second power transmission coil 12b is disconnected.

  Hereinafter, the state where the second power transmission circuit 11b and the both ends of the second power transmission coil 12b are electrically connected is abbreviated as the connection state between the second power transmission circuit 11b and the second power transmission coil 12b. . Further, the second power transmission circuit 11b and the second power transmission coil 12b are in a disconnected state that the electrical connection between the second power transmission circuit 11b and the both ends of the second power transmission coil 12b is disconnected. Abbreviated. As the second switch element 13b, a switching semiconductor such as an FET is used.

  The control circuit 14 is connected to an input device such as an operation switch (not shown). Then, the control circuit 14 selects which one of the electromagnetic induction method and the magnetic resonance method is used for power transmission based on a predetermined input operation on the input device. Then, the first switch element 13a and the second switch element 13b are controlled corresponding to the selected transmission method, the connection state of the first power transmission circuit 11a and the first power transmission coil 12a, the second power transmission circuit 11b and the second power transmission circuit 11b. 2 The connection state with the power transmission coil 12b is switched.

  As shown in FIG. 3A, when performing power transmission corresponding to the electromagnetic induction method, the control circuit 14 turns the first switch element 13a on and the second switch element 13b off. As a result, the first power transmission circuit 11a and the first power transmission coil 12a are connected, and the second power transmission circuit 11b and the second power transmission coil 12b are disconnected. And the electric signal corresponding to an electromagnetic induction system is applied from the 1st power transmission circuit 11a to the 1st power transmission coil 12a, and the magnetic field corresponding to the electrical signal to which the 1st power transmission coil 12a was applied is generated. The second power transmission coil 12b is disconnected from the second power transmission circuit 11b.

  On the other hand, as shown in FIG. 3B, when performing power transmission corresponding to the magnetic resonance method, the control circuit 14 turns the first switch element 13a off and the second switch element 13b on. As a result, the second power transmission circuit 11b and the second power transmission coil 12b are connected, and the first power transmission circuit 11a and the first power transmission coil 12a are disconnected. And the electric signal corresponding to a magnetic resonance system is applied to the 2nd power transmission coil 12b from the 2nd power transmission circuit 11b, and the magnetic field corresponding to the electrical signal to which the 2nd power transmission coil 12b was applied is generated. The first power transmission coil 12a is disconnected from the first power transmission circuit 11a.

  The case 15 is a substantially rectangular parallelepiped member made of synthetic resin or the like, and includes a circuit housing portion 15a and a coil housing portion 15b. As shown in FIG. 2, the coil accommodating portion 15b accommodates a first power transmission coil 12a and a second power transmission coil 12b. Although not shown, the circuit housing portion 15a houses the first power transmission circuit 11a, the second power transmission circuit 11b, the first switch element 13a, the second switch element 13b, and the control circuit 14.

  The cover 16 is a plate-like member made of synthetic resin or the like, and has a substantially rectangular plate surface on the top and bottom. And the cover 16 is being fixed to the upper side of the case 15 so that the circuit accommodating part 15a and the coil accommodating part 15b may be covered. The upper surface of the cover 16 serves as a power feeding surface 16a on which the power receiving device 20 is placed. The 1st power transmission coil 12a and the 2nd power transmission coil 12b are arrange | positioned under the electric power feeding surface 16a (back side).

  The power receiving device 20 is a power receiving device corresponding to one of the electromagnetic induction method and the magnetic resonance method. The power receiving device 20 may be a power receiving device fixed to one of the transmission methods, or a power receiving device capable of switching the transmission method by an operation switch or the like. As illustrated in FIG. 1, the power receiving device 20 includes a power receiving coil 21, a power receiving circuit 22, and a load 23. As shown in FIG. 2, the power receiving device 20 is placed on the power feeding surface 16 a so that the power transmission coil 12 and the power receiving coil 21 face each other with the cover 16 interposed therebetween.

  The power receiving coil 21 is magnetically coupled to one of the two power transmitting coils 12. When the power receiving device 20 is a device compatible with the electromagnetic induction method, the power receiving coil 21 is magnetically coupled to the first power transmitting coil 12a as shown in FIG. In that case, the 1st power transmission coil 12a and the receiving coil 21 are couple | bonded by electromagnetic induction.

  When the power receiving device 20 is a device compatible with the magnetic resonance system, the power receiving coil 21 is magnetically coupled to the second power transmitting coil 12b as shown in FIG. In that case, the power receiving coil 21 resonates at a predetermined frequency, and the second power transmitting coil 12b and the power receiving coil 21 are coupled by magnetic resonance.

  Then, the AC electrical signal applied to the power transmission coil 12 is transmitted to the power reception coil 21 by magnetic field coupling between the power transmission coil 12 and the power reception coil 21. Although not shown, the power receiving coil 21 is also formed by winding a conductive wire made of metal into a predetermined shape, like the power transmitting coil 12.

  The power receiving circuit 22 is a circuit having a rectifier circuit, a smoothing circuit, and the like. The power receiving circuit 22 is connected to both ends of the power receiving coil 21. The power receiving circuit 22 rectifies and smoothes the AC electrical signal transmitted to the power receiving coil 21 and converts it into a DC electrical signal, and then outputs it to the load 23. As described above, the wireless power transmission system 1 wirelessly transmits power from the power transmission device 10 to the power reception device 20 by using the magnetic field coupling between the power transmission coil 12 and the power reception coil 21.

  Next, the transmission efficiency from the power transmitting apparatus 10 to the power receiving apparatus 20 will be described with reference to FIG. FIG. 4 is an explanatory diagram showing the distribution of magnetic flux generated by the power transmission coil 12 shown in FIG. Fig.4 (a) is a figure which shows typically distribution of the magnetic flux B1 which the 1st power transmission coil 12a generated. FIG. 4B is a diagram schematically showing the distribution of the magnetic flux B2 generated by the second power transmission coil 12b. 4A and 4B show the distribution of magnetic flux when the first power transmission coil 12a and the second power transmission coil 12b are viewed from the side.

  First, the magnetic field coupling between the power transmission coil 12 and the power reception coil 21 when performing power transmission corresponding to the electromagnetic induction method will be described. When power transmission corresponding to the electromagnetic induction method is performed, an electric signal for power transmission is applied to the first power transmission coil 12a. And as shown to Fig.4 (a), the 1st power transmission coil 12a generates the magnetic flux B1 around self. Although not shown, a magnetic field is formed around the first power transmission coil 12a corresponding to the magnetic flux B1 generated by the first power transmission coil 12a. Then, the magnetic field formed above the first power transmission coil 12a magnetically couples the first power transmission coil 12a and the power reception coil 21, and power transmission from the power transmission device 10 to the power reception device 20 becomes possible.

  Further, a magnetic field is also formed around the second power transmission coil 12b corresponding to the magnetic flux B1 generated by the first power transmission coil 12a. Then, the first power transmission coil 12a and the second power transmission coil 12b are magnetically coupled by the magnetic field formed around the second power transmission coil 12b. When the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b becomes strong, a part of the electrical signal applied to the first power transmission coil 12a is also transmitted to the second power transmission coil 12b.

  Next, transmission efficiency when performing power transmission corresponding to the electromagnetic induction method will be described. The power transmitted from the power transmission device 10 using the first power transmission coil 12a is Pt, the power transmitted to the power reception device 20 by magnetic coupling between the first power transmission coil 12a and the power reception coil 21 is Pr, and the first power transmission coil 12a. Pm is the power that is transmitted to the second power transmission circuit 11b by magnetic field coupling between the power transmission device 12b and the second power transmission coil 12b, and η is the transmission efficiency from the power transmission device 10 to the power reception device 20, and there is power loss other than the power Pm. If there is no transmission efficiency, η can be expressed as η = Pr / Pt = Pr / (Pr + Pm).

  Further, the load resistance on the power receiving circuit 22 side as viewed from the power receiving coil 21 side is Rr, the current flowing through the power receiving circuit 22 along with the power transmission from the power transmitting device 10 to the power receiving device 20 is viewed from the second power transmitting coil 12b side. When the load resistance on the second power transmission circuit 11b side is Rm, and the current flowing through the second power transmission circuit 11b due to the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b is Im, the power Pr is Pr = Rr · Ir ^ 2, power Pm can be expressed as Pm = Rm · Im ^ 2, and transmission efficiency η can be expressed as η = (Rr · Ir ^ 2) / (Rr · Ir ^ 2 + Rm · Im ^ 2).

  As can be seen from the above equation, the transmission efficiency η decreases as the current Im flowing through the second power transmission circuit 11b increases with the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b. On the other hand, even if the first power transmission coil 12a and the second power transmission coil 12b are magnetically coupled, the second power transmission circuit 11b and the second power transmission coil 12b are not connected, and the current Im flows through the second power transmission circuit 11b. If not, no power loss occurs in the second power transmission circuit 11b, and a decrease in transmission efficiency can be suppressed.

  Next, magnetic field coupling between the power transmission coil 12 and the power reception coil 21 when performing power transmission corresponding to the magnetic resonance method will be described. When power transmission corresponding to the magnetic resonance method is performed, an electrical signal for power transmission is applied to the second power transmission coil 12b. And as shown in FIG.4 (b), the 2nd power transmission coil 12b generates the magnetic flux B2 around self. Although not shown, a magnetic field is formed around the second power transmission coil 12b corresponding to the magnetic flux B2 generated by the second power transmission coil 12b. The first power transmission coil 12a and the power reception coil 21 are magnetically coupled by the magnetic field formed above the second power transmission coil 12b, and power transmission from the power transmission device 10 to the power reception device 20 becomes possible.

  Further, a magnetic field is also formed around the first power transmission coil 12a corresponding to the magnetic flux B2 generated by the second power transmission coil 12b. The first power transmission coil 12a and the second power transmission coil 12b are magnetically coupled by the magnetic field formed around the first power transmission coil 12a. When the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b becomes stronger, a part of the electrical signal applied to the second power transmission coil 12b is also transmitted to the first power transmission coil 12a.

  Although detailed description is omitted about the transmission efficiency when the power receiving apparatus 20 is an apparatus corresponding to a magnetic resonance system, even if the first power transmission coil 12a and the second power transmission coil 12b are magnetically coupled, the first power transmission If the circuit 11a and the first power transmission coil 12a are not connected and no current flows through the first power transmission circuit 11a, no power loss occurs in the first power transmission circuit 11a, and a decrease in transmission efficiency is suppressed. be able to.

  Normally, since the magnetic flux generated by the coil is concentrated inside the coil, the magnetic flux density inside the coil becomes high, and accordingly, the magnetic field strength inside the coil becomes strong. On the other hand, the magnetic flux density is reduced outside the coil, and accordingly, the magnetic field strength outside the coil is weakened. And in this embodiment, the coil diameter of the 2nd power transmission coil 12b is larger than the coil diameter of the 1st power transmission coil 12a, and the 2nd power transmission coil 12b surrounds the circumference | surroundings of the 1st power transmission coil 12a in planar view. Has been placed. Therefore, in comparison with the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b by the magnetic flux B2 generated by the second power transmission coil 12b, the first power transmission coil by the magnetic flux B1 generated by the first power transmission coil 12a. Magnetic field coupling between 12a and the second power transmission coil 12b is weaker.

  Next, the effect of this embodiment will be described. In the wireless power transmission system 1 according to the present embodiment, the power transmission device 10 includes a first power transmission circuit 11a corresponding to the electromagnetic induction method, a second power transmission circuit 11b corresponding to the magnetic resonance method, and a first corresponding to the electromagnetic induction method. It has the power transmission coil 12a and the 2nd power transmission coil 12b corresponding to a magnetic resonance system. Therefore, power can be transmitted from the power transmission device 10 to the power reception device 20 regardless of which of the two transmission methods the power reception device 20 is.

  Moreover, the power transmission device 10 switches the first switch element 13a that switches the connection state between the first power transmission circuit 11a and the first power transmission coil 12a, and the second that switches the connection state between the second power transmission circuit 11b and the second power transmission coil 12b. A switch element 13b and a control circuit 14 for controlling the first switch element 13a and the second switch element 13b are provided. And when the 1st power transmission circuit 11a and the 1st power transmission coil 12a are a connection state, the control circuit 14 will be in a connection state with the 2nd power transmission circuit 11b and the 2nd power transmission coil 12b. When the second power transmission coil 12b is in a connected state, the first switch element 13a and the second switch element 13b are controlled so that the first power transmission circuit 11a and the first power transmission coil 12a are in a disconnected state. Yes.

  Therefore, even if the electric signal applied to the 1st power transmission coil 12a is transmitted to the 2nd power transmission coil 12b by the magnetic field coupling of the 1st power transmission coil 12a and the 2nd power transmission coil 12b, the 2nd power transmission circuit 11b and the 2nd By making the power transmission coil 12b non-connected, it is possible to prevent unnecessary current from flowing through the second power transmission circuit 11b. Moreover, even if the electric signal applied to the 2nd power transmission coil 12b is transmitted to the 1st power transmission coil 12a by the magnetic field coupling of the 1st power transmission coil 12a and the 2nd power transmission coil 12b, the 1st power transmission circuit 11a and the 1st By setting the power transmission coil 12a to the disconnected state, it is possible to prevent unnecessary current from flowing through the first power transmission circuit 11a. As a result, power loss on the power transmission device 10 side can be suppressed, and a decrease in transmission efficiency from the power transmission device 10 to the power reception device 20 can be suppressed.

  Further, in the wireless power transmission system 1 of the present embodiment, the first power transmission coil 12a is a coil compatible with electromagnetic induction wireless power transmission, and the second power transmission coil 12b is compatible with magnetic resonance wireless power transmission. Coil. The electromagnetic induction method is a transmission method that transmits power by bringing a power transmission coil and a power reception coil close to each other. The magnetic resonance method can transmit power even when the distance between the power transmission coil and the power reception coil is long. It is a simple transmission method. Therefore, in the wireless power transmission system 1, even when the power transmission device 10 and the power reception device 20 are close to each other or when the distance between the power transmission device 10 and the power reception device 20 is long, the power transmission device 10 to the power reception device 20. Electric power can be transmitted. As a result, the degree of freedom with respect to the distance between the power transmission device 10 and the power reception device 20 can be expanded.

  Moreover, in the wireless power transmission system 1 of the present embodiment, the coil diameter of the second power transmission coil 12b is larger than the coil diameter of the first power transmission coil 12a, and the second power transmission coil 12b is in the first view when viewed in plan. It is arranged so that it surrounds Therefore, even when the second power transmission coil 12b is a spiral coil wound around the outer periphery of the circle and a space is formed inside the second power transmission coil 12b, the inner side of the second power transmission coil 12b. Thus, the power transmission device 10 can be downsized.

  Moreover, in the wireless power transmission system 1 of the present embodiment, the power transmission device 10 has the power feeding surface 16a on which the power receiving device 20 is placed, and the first power transmission coil 12a and the second power transmission coil 12b are the power feeding surface 16a. It is arranged on the lower side (back side). Therefore, it is easy to stabilize the distance between the power transmission coil 12 and the power reception coil 21, and power can be stably transmitted from the power transmission device 10 to the power reception device 20. Moreover, in the wireless power transmission system 1, the second power transmission coil 12b is a coil that supports magnetic resonance wireless power transmission, and the coil diameter of the second power transmission coil 12b is the coil diameter of the first power transmission coil 12a. Bigger than. In the magnetic resonance type wireless power transmission, the larger the outer diameter of the power transmission coil 12, the longer the transmission distance (distance at which power can be transmitted effectively). Therefore, even when the power receiving device 20 is separated from the power feeding surface 16a, it is easy to maintain power transmission from the power transmitting device 10 to the power receiving device 20.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In addition, in this embodiment, when it is the same structure as 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  First, the configuration of the wireless power transmission system 101 according to the second embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing a configuration of the wireless power transmission system 101 according to the second embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating a method for switching the connection state of the power transmission device 110 illustrated in FIG. 5. FIG. 6A shows a connection state when power transmission corresponding to the electromagnetic induction method is performed. FIG. 6B shows a connection state when power transmission corresponding to the magnetic resonance method is performed.

  As shown in FIG. 5, the wireless power transmission system 101 includes a power transmission device 110 and a power reception device 120. The configuration of the power receiving device 120 is the same as the configuration of the power receiving device 20 in the first embodiment. The configuration of the power transmission device 110 is substantially the same as the configuration of the power transmission device 10 in the first embodiment. However, in this embodiment, the connection between the second power transmission circuit 11b and the second power transmission coil 12b is different from that in the first embodiment. . In the power transmission device 110, there is no second switch element 13b, and the second power transmission circuit 11b and the second power transmission coil 12b are always connected.

  As shown in FIG. 6, when the control circuit 14 performs power transmission corresponding to the electromagnetic induction method, that is, when an electric signal for power transmission is applied to the first power transmission coil 12 a, the control circuit 14 and the first power transmission circuit 11 a The first switch element 13a is controlled so that the first power transmission coil 12a is connected. In addition, when the control circuit 14 performs power transmission corresponding to the magnetic resonance method, that is, when an electric signal for power transmission is applied to the second power transmission coil 12b, the first power transmission circuit 11a and the first power transmission coil 12a The first switch element 13a is controlled so as to be in a disconnected state.

  The structure of the power transmission coil 12 is the same as the structure of the power transmission coil 12 in the first embodiment. That is, the coil diameter of the 2nd power transmission coil 12b is larger than the coil diameter of the 1st power transmission coil 12a, and the 2nd power transmission coil 12b is arrange | positioned so that the circumference | surroundings of the 1st power transmission coil 12a may be enclosed in planar view. Therefore, as in the first embodiment, the first power transmission coil 12a is generated compared to the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b by the magnetic flux B2 generated by the second power transmission coil 12b. Magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b by the magnetic flux B1 becomes weaker.

  Next, the effect of this embodiment will be described. In the wireless power transmission system 101 according to the present embodiment, the power transmission device 110 includes a first power transmission circuit 11a corresponding to the electromagnetic induction method, a second power transmission circuit 11b corresponding to the magnetic resonance method, and a first corresponding to the electromagnetic induction method. It has the power transmission coil 12a and the 2nd power transmission coil 12b corresponding to a magnetic resonance system. Therefore, power can be transmitted from power transmission device 110 to power reception device 120 regardless of which of the two transmission methods is used by power reception device 120.

  And the power transmission apparatus 110 has the switch element 13 which switches the connection state of the 1st power transmission circuit 11a and the 1st power transmission coil 12a, and the control circuit 14 which controls the switch element 13. FIG. And when the control circuit 14 applies the electric signal for power transmission to the 1st power transmission coil 12a, the 1st power transmission circuit 11a and the 1st power transmission coil 12a will be in a connection state, and the electric power for power transmission to the 2nd power transmission coil 12b. When a signal is applied, the switch element 13 is controlled so that the first power transmission circuit 11a and the first power transmission coil 12a are disconnected. Therefore, even if the electric signal applied to the second power transmission coil 12b is transmitted to the first power transmission coil 12a due to the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b, the first power transmission circuit 11a and the first power transmission circuit 11a By setting the power transmission coil 12a to the disconnected state, it is possible to prevent unnecessary current from flowing through the first power transmission circuit 11a.

  Moreover, the coil diameter of the 2nd power transmission coil 12b is set larger than the coil diameter of the 1st power transmission coil 12a, and the 2nd power transmission coil 12b is a 1st power transmission coil 12a seeing from a top (in planar view). It is arranged so that it surrounds Therefore, in comparison with the magnetic field coupling between the first power transmission coil 12a and the second power transmission coil 12b by the magnetic flux B2 generated by the second power transmission coil 12b, the first power transmission coil by the magnetic flux B1 generated by the first power transmission coil 12a. Magnetic field coupling between 12a and the second power transmission coil 12b can be weakened. And it can suppress that the electric signal applied to the 1st power transmission coil 12a is transmitted to the 2nd power transmission coil 12b. As a result, power loss on the power transmission device 110 side can be suppressed, and a decrease in transmission efficiency from the power transmission device 110 to the power reception device 120 can be suppressed.

  Further, in the wireless power transmission system 101 of the present embodiment, the first power transmission coil 12a is a coil compatible with electromagnetic induction wireless power transmission, and the second power transmission coil 12b is compatible with magnetic resonance wireless power transmission. Coil. The electromagnetic induction method is a transmission method that transmits power by bringing a power transmission coil and a power reception coil close to each other. The magnetic resonance method can transmit power even when the distance between the power transmission coil and the power reception coil is long. It is a simple transmission method. Therefore, in the wireless power transmission system 101, the power transmission device 110 and the power reception device 120 are connected to each other even when the power transmission device 110 and the power reception device 120 are close to each other or when the distance between the power transmission device 110 and the power reception device 120 is long. Electric power can be transmitted, and the degree of freedom with respect to the distance between the power transmission device 110 and the power reception device 120 can be expanded.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. In the present embodiment, switching of the connection state between the power transmission circuit 11 and the power transmission coil 12 in the power transmission device 10 of the first embodiment is applied to the power reception device side. In addition, in this embodiment, when it is the same structure as 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  First, the structure of the wireless power transmission system 201 according to the third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram showing a configuration of a wireless power transmission system 201 according to the third embodiment of the present invention. FIG. 8 is an explanatory diagram illustrating a method for switching the connection state of the power receiving device 220 illustrated in FIG. 7. FIG. 8A shows a connection state when power transmission corresponding to the electromagnetic induction method is performed. FIG. 8B shows a connection state when power transmission corresponding to the magnetic resonance method is performed.

  As shown in FIG. 7, the wireless power transmission system 201 includes a power transmission device 210 and a power reception device 220.

  The power transmission device 210 is a power transmission device corresponding to one of the electromagnetic induction method and the magnetic resonance method. The power transmission device 210 may be a power transmission device fixed to one of the transmission methods, or may be a power transmission device whose transmission method can be switched by an operation switch or the like. As illustrated in FIG. 7, the power transmission device 210 includes a power transmission circuit 11 and a power transmission coil 12. When the power transmission device 210 is a device compatible with the electromagnetic induction method, the power transmission circuit 11 and the power transmission coil 12 correspond to the electromagnetic induction method, and when the power transmission device 210 is a device compatible with the magnetic resonance method, The power transmission coil 12 corresponds to the magnetic resonance method.

  The power receiving device 220 is a power receiving device that supports both the electromagnetic induction method and the magnetic resonance method. As shown in FIG. 7, the power receiving device 220 includes two power receiving coils 21, two power receiving circuits 22, a load 23, two switch elements 24, and a control circuit 25 (control unit) that controls the switch elements 24. And have. The two power receiving coils 21 are a first power receiving coil 21a and a second power receiving coil 21b. The two power receiving circuits 22 are a first power receiving circuit 22a and a second power receiving circuit 22b. The two switch elements 24 are a third switch element 24a and a fourth switch element 24b.

  The first power receiving coil 21a corresponds to an electromagnetic induction method. Although not shown, the first power receiving coil 21a is a spiral coil wound around the outer circumference of a circle. Both end portions of the first power receiving coil 21a are connected to the first power receiving circuit 22a via the third switch element 24a and wiring.

  The second power receiving coil 21b corresponds to the magnetic resonance method. Although not shown, the second power receiving coil 21b is a spiral coil wound around the outer circumference of a circle. The coil diameter of the second power receiving coil 21b is set to be larger than the coil diameter of the first power receiving coil 21a. The second power receiving coil 21b is viewed from above (in plan view) and around the first power receiving coil 21a. Is arranged so as to surround. Both ends of the second power receiving coil 21b are connected to the second power receiving circuit 22b through the fourth switch element 24b and wiring.

  The first power receiving circuit 22a is a power receiving circuit compatible with the electromagnetic induction method, and the second power receiving circuit 22b is a power receiving circuit compatible with the magnetic resonance method. The third switch element 24a switches the connection state between the first power receiving coil 21a and the first power receiving circuit 22a. The fourth switch element 24b switches the connection state between the second power receiving coil 21b and the second power receiving circuit 22b.

  Then, as shown in FIG. 8, the control circuit 25 performs the second power reception when performing power transmission corresponding to the electromagnetic induction method, that is, when the first power reception coil 21a and the first power reception circuit 22a are in the connected state. The third switch element 24a and the fourth switch element 24b are controlled so that the coil 21b and the second power receiving circuit 22b are disconnected. Further, the control circuit 25 performs power transmission corresponding to the magnetic resonance method, that is, when the second power receiving coil 21b and the second power receiving circuit 22b are in a connected state, the first power receiving coil 21a and the first power receiving circuit. The third switch element 24a and the fourth switch element 24b are controlled so that the terminal 22a is disconnected.

  Next, the effect of this embodiment will be described. In the wireless power transmission system 201 of the present embodiment, the power receiving device 220 includes a first power receiving coil 21a that is compatible with the electromagnetic induction method, a second power receiving coil 21b that is compatible with the magnetic resonance method, and a first power source that is compatible with the electromagnetic induction method. The power receiving circuit 22a and the second power receiving circuit 22b corresponding to the magnetic resonance method are included. Therefore, power can be transmitted from the power transmission apparatus 210 to the power reception apparatus 220 regardless of which of the two transmission systems the power transmission apparatus 210 is capable of.

  Moreover, the power receiving apparatus 220 is configured to switch the connection state between the third switch element 24a that switches the connection state between the first power reception coil 21a and the first power reception circuit 22a, and the connection state between the second power reception coil 21b and the second power reception circuit 22b. A switch circuit 24b and a control circuit 25 that controls the third switch element 24a and the fourth switch element 24b are provided. When the first power receiving coil 21a and the first power receiving circuit 22a are connected, the second power receiving coil 21b and the second power receiving circuit 22b are disconnected from each other, and the second power receiving coil 21b and the second power receiving circuit 22b are connected. Are in a connected state, the first power receiving coil 21a and the first power receiving circuit 22a are in a disconnected state.

  Therefore, even if a part of the electrical signal transmitted from the power transmission coil 12 to the first power receiving coil 21a is transmitted to the second power receiving coil 21b by the magnetic field coupling between the first power receiving coil 21a and the second power receiving coil 21b, By setting the second power receiving coil 21b and the second power receiving circuit 22b in a disconnected state, it is possible to prevent unnecessary current from flowing through the second power receiving circuit 22b. Further, even if a part of the electrical signal transmitted from the power transmission coil 12 to the second power receiving coil 21b is transmitted to the first power receiving coil 21a by the magnetic field coupling between the first power receiving coil 21a and the second power receiving coil 21b, the first power receiving coil 21a By setting the first power receiving coil 21a and the first power receiving circuit 22a in a disconnected state, it is possible to prevent an unnecessary current from flowing through the first power receiving circuit 22a. As a result, power loss on the power receiving apparatus 220 side can be suppressed, and a decrease in transmission efficiency from the power transmitting apparatus 210 to the power receiving apparatus 220 can be suppressed.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. In the present embodiment, switching of the connection state between the power transmission circuit 11 and the power transmission coil 12 in the power transmission device 110 of the second embodiment is applied to the power reception device side. In addition, in this embodiment, when it is the same structure as 1st Embodiment thru | or 3rd Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  First, the configuration of the wireless power transmission system 301 according to the fourth embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a block diagram showing a configuration of a wireless power transmission system 301 according to the fourth embodiment of the present invention. FIG. 10 is an explanatory diagram illustrating a method for switching the connection state of the power transmission device 320 illustrated in FIG. 9. FIG. 10A shows a connection state when power transmission corresponding to the electromagnetic induction method is performed. FIG. 10B shows a connection state when power transmission corresponding to the magnetic resonance method is performed.

  As illustrated in FIG. 9, the wireless power transmission system 301 includes a power transmission device 310 and a power reception device 320. The configuration of the power transmission device 310 is the same as the configuration of the power transmission device 210 in the third embodiment. The configuration of the power receiving device 320 is substantially the same as the configuration of the power receiving device 220 in the third embodiment. However, in this embodiment, the connection between the second power receiving coil 21b and the second power receiving circuit 22b is different from that in the third embodiment. . In the power receiving device 320, there is no fourth switch element 24b, and the second power receiving coil 21b and the second power receiving circuit 22b are always connected. The structure of the power receiving coil 21 is the same as the structure of the power receiving coil 21 in the third embodiment.

  As shown in FIG. 10, the control circuit 25 performs the first power receiving coil 21a when performing power transmission corresponding to the electromagnetic induction method, that is, when transmitting an electric signal from the power transmitting coil 12 to the first power receiving coil 21a. And the first power receiving circuit 22a are controlled so that the third switch element 24a is controlled. In addition, the control circuit 25 performs the power transmission corresponding to the magnetic resonance method, that is, when an electric signal is transmitted from the power transmission coil 12 to the second power receiving coil 21b, the first power receiving coil 21a and the first power receiving circuit 22a The third switch element 24a is controlled so as to be in a disconnected state.

  Next, the effect of this embodiment will be described. In the wireless power transmission system 301 according to the present embodiment, the power receiving device 320 includes a first power receiving coil 21a corresponding to the electromagnetic induction method, a second power receiving coil 21b corresponding to the magnetic resonance method, and a first power corresponding to the electromagnetic induction method. The power receiving circuit 22a and the second power receiving circuit 22b corresponding to the magnetic resonance method are included. Therefore, power can be transmitted from the power transmission device 310 to the power reception device 320 regardless of which of the two transmission methods the power transmission device 310 is.

  In addition, the power receiving device 320 includes a third switch element 24a that switches a connection state between the first power receiving coil 21a and the first power receiving circuit 22a, and a control circuit 25 that controls the third switch element 24a. When the electric signal is transmitted from the power transmission coil 12 to the first power reception coil 21a, the first power reception coil 21a and the first power reception circuit 22a are connected, and the electric signal is transmitted from the power transmission coil 12 to the second power reception coil 21b. When it does, the 1st receiving coil 21a and the 1st receiving circuit 22a will be in a disconnection state. Therefore, even if a part of the electrical signal transmitted from the power transmission coil 12 to the first power receiving coil 21a is transmitted to the second power receiving coil 21b by the magnetic field coupling between the first power receiving coil 21a and the second power receiving coil 21b, By setting the second power receiving coil 21b and the second power receiving circuit 22b in a disconnected state, it is possible to prevent unnecessary current from flowing through the second power receiving circuit 22b.

  The coil diameter of the second power receiving coil 21b is set to be larger than the coil diameter of the first power receiving coil 21a, and the second power receiving coil 21b is viewed from above (in plan view), and the first power receiving coil 21a. It is arranged so that it surrounds Therefore, as compared with the magnetic field coupling between the first power receiving coil 21a and the second power receiving coil 21b by the magnetic flux generated by the second power receiving coil 21b, the first power receiving coil 21a by the magnetic flux generated by the first power receiving coil 21a and The magnetic field coupling with the second power receiving coil 21b can be weakened. And it can suppress that a part of electrical signal transmitted to the 1st receiving coil 21a is transmitted to the 2nd receiving coil 21b. As a result, power loss on the power reception device 320 side can be suppressed, and a decrease in transmission efficiency from the power transmission device 310 to the power reception device 320 can be suppressed.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to said embodiment, In the range which does not deviate from the objective of this invention, it can change suitably.

  In the embodiment of the present invention, the power transmission circuit 11 may have a configuration other than that described above. For example, the first power transmission circuit 11a and the second power transmission circuit 11b may share part of the circuit. Further, the first power transmission circuit 11a and the second power transmission circuit 11b may be an amplifier circuit connected to the oscillation circuit instead of the inverter circuit. The power transmission circuit 11 may appropriately change the frequency of the electric signal to be generated in accordance with the system standard. The power receiving circuit 22 may have a configuration other than that described above. For example, the first power receiving circuit 22a and the second power receiving circuit 22b may share a part of the circuit. Further, the power receiving device 20 (or the power receiving device 120, the power receiving device 220, and the power receiving device 320) does not have the load 23, and the power receiving circuit 22 may be connected to another electronic device serving as a load.

  In the embodiment of the present invention, the power transmission coil 12 and the power reception coil 21 may be made of materials and shapes other than those described above. For example, the number of turns of the power transmission coil 12 and the power reception coil 21 may be appropriately changed according to the system standard. Moreover, the power transmission coil 12 and the power reception coil 21 may be a spiral coil wound along a polygonal outer periphery instead of a spiral coil wound along a circular outer periphery. The power transmission coil 12 and the power reception coil 21 may be helical coils instead of spiral coils. The power transmission coil 12 and the power reception coil 21 may be coils formed as electrode patterns on the plate surface of the substrate. Moreover, the capacity | capacitance etc. for adjusting a resonant frequency may be added to the 2nd power transmission coil 12b or the 2nd power receiving coil 21b.

  In the embodiment of the present invention, as long as a predetermined function can be realized, the direction of the power feeding surface 16a may be appropriately changed according to the use conditions. Moreover, the power transmission coil 12 may be accommodated in a separate member separable from the case 15 and connected to the power transmission circuit 11 via wiring.

  In the embodiment of the present invention, the switch element 13 and the switch element 24 may be mechanical switch elements such as a MEMS element and a relay. Moreover, if the predetermined function can be realized, the switch element 13 does not switch the connection state between the both ends of the power transmission coil 12 and the power transmission circuit 11, but instead of one end of the power transmission coil 12 and the power transmission circuit 11. It is possible to switch only the connection state. The switch element 24 may switch only the connection state between one end of the power receiving coil 21 and the power receiving circuit 22 instead of switching the connection state between the both ends of the power receiving coil 21 and the power receiving circuit 22. .

  In the embodiment of the present invention, the power transmission device 10 (or the power transmission device 110) performs wireless communication with the detection unit for detecting the transmission method of the power reception device 20 or the power reception device 20 (or the power reception device 120). You may further have a communication means for performing. The control circuit 14 automatically determines which of the electromagnetic induction method and the magnetic resonance method is used for power transmission based on the detection result of the detection means, the communication result with the power receiving device 20, and the like. You can choose.

DESCRIPTION OF SYMBOLS 1 Wireless power transmission system 10 Power transmission apparatus 11 Power transmission circuit 11a 1st power transmission circuit 11b 2nd power transmission circuit 12 Power transmission coil 12a 1st power transmission coil 12b 2nd power transmission coil 13 Switch element 13a 1st switch element 13b 2nd switch element 14 Control circuit DESCRIPTION OF SYMBOLS 15 Case 15a Circuit accommodating part 15b Coil accommodating part 16 Cover 16a Power feeding surface 20 Power receiving apparatus 21 Power receiving coil 22 Power receiving circuit 23 Load 101 Wireless power transmission system 110 Power transmitting apparatus 120 Power receiving apparatus 201 Wireless power transmission system 210 Power transmitting apparatus 220 Power receiving apparatus 21a 1st 1 receiving coil 21b 2nd receiving coil 22a 1st receiving circuit 22b 2nd receiving circuit 24 switch element 24a 3rd switch element 24b 4th switch element 25 control circuit 301 wireless power transmission system 310 power transmission apparatus 20 powered device

Claims (10)

A power transmission device having a power transmission coil;
A power receiving device having a power receiving coil,
Utilizing magnetic field coupling between the power transmission coil and the power reception coil,
A wireless power transmission system that wirelessly transmits power from the power transmission device to the power reception device,
The power transmission device is:
A first power transmission circuit corresponding to the first transmission method;
A second power transmission circuit corresponding to the second transmission method;
A first power transmission coil corresponding to the first transmission method;
A second power transmission coil corresponding to the second transmission method;
A first switch element for switching a connection state between the first power transmission circuit and the first power transmission coil;
A second switch element for switching a connection state between the second power transmission circuit and the second power transmission coil;
A control unit that controls the first switch element and the second switch element;
The first power transmission coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission system,
The second power transmission coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission system,
The controller is
When the first power transmission circuit and the first power transmission coil are in a connected state,
The second power transmission circuit and the second power transmission coil are disconnected from each other,
When the second power transmission circuit and the second power transmission coil are in a connected state,
In order for the first power transmission circuit and the first power transmission coil to be in a disconnected state,
A wireless power transmission system that controls the first switch element and the second switch element. Of the first power transmission coil and the second power transmission coil,
The coil diameter of one coil is larger than the coil diameter of the other coil,
The one coil is arranged to surround the other coil in a plan view,
The wireless power transmission system according to claim 1 . The power transmission device is:
A power supply surface on which the power receiving device is placed;
The first power transmission coil and the second power transmission coil are:
Arranged on the back side of the feeding surface,
The coil diameter of the second power transmission coil is
The coil diameter of the first power transmission coil is larger,
The wireless power transmission system according to claim 2 . A power transmission device having a power transmission coil;
A power receiving device having a power receiving coil,
Utilizing magnetic field coupling between the power transmission coil and the power reception coil,
A wireless power transmission system that wirelessly transmits power from the power transmission device to the power reception device,
The power transmission device is:
A first power transmission circuit corresponding to the first transmission method;
A second power transmission circuit corresponding to the second transmission method;
A first power transmission coil corresponding to the first transmission method;
A second power transmission coil corresponding to the second transmission method;
A switch element for switching a connection state between the first power transmission circuit and the first power transmission coil;
A control unit for controlling the switch element,
The first power transmission coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission system,
The second power transmission coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission system,
The coil diameter of the second power transmission coil is larger than the coil diameter of the first power transmission coil,
The second power transmission coil is disposed so as to surround the first power transmission coil in a plan view.
The controller is
When applying an electric signal for power transmission to the first power transmission coil,
The first power transmission circuit and the first power transmission coil are connected,
When applying an electrical signal for power transmission to the second power transmission coil,
In order for the first power transmission circuit and the first power transmission coil to be in a disconnected state,
A wireless power transmission system for controlling the switch element. A power transmission device having a power transmission coil;
A power receiving device having a power receiving coil,
Utilizing magnetic field coupling between the power transmission coil and the power reception coil,
A wireless power transmission system that wirelessly transmits power from the power transmission device to the power reception device,
The power receiving device is:
A first power receiving coil corresponding to the first transmission method;
A second power receiving coil corresponding to the second transmission method;
A first power receiving circuit corresponding to the first transmission method;
A second power receiving circuit corresponding to the second transmission method;
A third switch element for switching a connection state between the first power receiving coil and the first power receiving circuit;
A fourth switch element for switching a connection state between the second power receiving coil and the second power receiving circuit;
A control unit for controlling the third switch element and the fourth switch element;
The first power receiving coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission method,
The second power receiving coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission method,
The controller is
When the first power receiving coil and the first power receiving circuit are in a connected state,
The second power receiving coil and the second power receiving circuit are disconnected from each other,
When the second power receiving coil and the second power receiving circuit are in a connected state,
The first power receiving coil and the first power receiving circuit are disconnected from each other.
A wireless power transmission system that controls the third switch element and the fourth switch element. A power transmission device having a power transmission coil;
A power receiving device having a power receiving coil,
Utilizing magnetic field coupling between the power transmission coil and the power reception coil,
A wireless power transmission system that wirelessly transmits power from the power transmission device to the power reception device,
The power receiving device is:
A first power receiving coil corresponding to the first transmission method;
A second power receiving coil corresponding to the second transmission method;
A first power receiving circuit corresponding to the first transmission method;
A second power receiving circuit corresponding to the second transmission method;
A switch element for switching a connection state between the first power receiving coil and the first power receiving circuit;
A control unit for controlling the switch element,
The first power receiving coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission method,
The second power receiving coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission method,
The coil diameter of the second power receiving coil is larger than the coil diameter of the first power receiving coil,
The second power receiving coil is disposed so as to surround the first power receiving coil in a plan view,
The controller is
When transmitting an electrical signal from the power transmission coil to the first power reception coil,
The first power receiving circuit and the first power receiving coil are connected,
When transmitting an electrical signal from the power transmission coil to the second power reception coil,
The first power receiving circuit and the first power receiving coil are disconnected from each other.
A wireless power transmission system for controlling the switch element.   A wireless transmission device comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and wirelessly transmitting power from the power transmission device to the power reception device using magnetic coupling between the power transmission coil and the power reception coil. The power transmission device in a power transmission system,
  A first power transmission circuit corresponding to the first transmission method;
  A second power transmission circuit corresponding to the second transmission method;
  A first power transmission coil corresponding to the first transmission method;
  A second power transmission coil corresponding to the second transmission method;
  A first switch element for switching a connection state between the first power transmission circuit and the first power transmission coil;
  A second switch element for switching a connection state between the second power transmission circuit and the second power transmission coil;
  A control unit that controls the first switch element and the second switch element;
  The first power transmission coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission system,
  The second power transmission coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission system,
  The controller is
  When the first power transmission circuit and the first power transmission coil are in a connected state,
  The second power transmission circuit and the second power transmission coil are disconnected from each other,
  When the second power transmission circuit and the second power transmission coil are in a connected state,
  In order for the first power transmission circuit and the first power transmission coil to be in a disconnected state,
  A power transmission device that controls the first switch element and the second switch element.   A wireless transmission device comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and wirelessly transmitting power from the power transmission device to the power reception device using magnetic coupling between the power transmission coil and the power reception coil. The power transmission device in a power transmission system,
  A first power transmission circuit corresponding to the first transmission method;
  A second power transmission circuit corresponding to the second transmission method;
  A first power transmission coil corresponding to the first transmission method;
  A second power transmission coil corresponding to the second transmission method;
  A switch element for switching a connection state between the first power transmission circuit and the first power transmission coil;
  A control unit for controlling the switch element,
  The first power transmission coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission system,
  The second power transmission coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission system,
  The coil diameter of the second power transmission coil is larger than the coil diameter of the first power transmission coil,
  The second power transmission coil is disposed so as to surround the first power transmission coil in a plan view.
  The controller is
  When applying an electric signal for power transmission to the first power transmission coil,
  The first power transmission circuit and the first power transmission coil are connected,
  When applying an electrical signal for power transmission to the second power transmission coil,
  In order for the first power transmission circuit and the first power transmission coil to be in a disconnected state,
  A power transmission device that controls the switch element.   A wireless transmission device comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and wirelessly transmitting power from the power transmission device to the power reception device using magnetic coupling between the power transmission coil and the power reception coil. The power receiving device in a power transmission system,
  A first power receiving coil corresponding to the first transmission method;
  A second power receiving coil corresponding to the second transmission method;
  A first power receiving circuit corresponding to the first transmission method;
  A second power receiving circuit corresponding to the second transmission method;
  A third switch element for switching a connection state between the first power receiving coil and the first power receiving circuit;
  A fourth switch element for switching a connection state between the second power receiving coil and the second power receiving circuit;
  A control unit for controlling the third switch element and the fourth switch element;
  The first power receiving coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission method,
  The second power receiving coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission method,
  The controller is
  When the first power receiving coil and the first power receiving circuit are in a connected state,
  The second power receiving coil and the second power receiving circuit are disconnected from each other,
  When the second power receiving coil and the second power receiving circuit are in a connected state,
  The first power receiving coil and the first power receiving circuit are disconnected from each other.
  The power receiving device controls the third switch element and the fourth switch element.   A wireless transmission device comprising: a power transmission device having a power transmission coil; and a power reception device having a power reception coil, and wirelessly transmitting power from the power transmission device to the power reception device using magnetic coupling between the power transmission coil and the power reception coil. The power receiving device in a power transmission system,
  A first power receiving coil corresponding to the first transmission method;
  A second power receiving coil corresponding to the second transmission method;
  A first power receiving circuit corresponding to the first transmission method;
  A second power receiving circuit corresponding to the second transmission method;
  A switch element for switching a connection state between the first power receiving coil and the first power receiving circuit;
  A control unit for controlling the switch element,
  The first power receiving coil is a coil corresponding to the electromagnetic transmission wireless power transmission that is the first transmission method,
  The second power receiving coil is a coil corresponding to a magnetic resonance wireless power transmission that is the second transmission method,
  The coil diameter of the second power receiving coil is larger than the coil diameter of the first power receiving coil,
  The second power receiving coil is disposed so as to surround the first power receiving coil in a plan view,
  The controller is
  When transmitting an electrical signal from the power transmission coil to the first power reception coil,
  The first power receiving circuit and the first power receiving coil are connected,
  When transmitting an electrical signal from the power transmission coil to the second power reception coil,
  The first power receiving circuit and the first power receiving coil are disconnected from each other.
  A power receiving device that controls the switch element.