Power transmission device, power reception device, and system

Abstract

To provide a power transmission device, a power reception device, and a system in which a magnetic flux can be cancelled in accordance with a peripheral environment.SOLUTION: In a system 1, a power transmission device capable of transmitting power that is wirelessly transmitted to a power reception device along a power transmission direction, includes: a power transmission coil; a first power transmission auxiliary coil in which the power transmission coil is positioned between the first power transmission auxiliary coil and the power reception device in the power transmission direction; and a second power transmission auxiliary coil that is positioned outside the power transmission coil in a direction intersecting the power transmission direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power transmission device, a power reception device, and a system.

Background Art

[0002] Patent Document 1 discloses a power transmission device that wirelessly transmits power to a device having a power reception coil by magnetic coupling. The power transmission device of Patent Document 1 has a cancellation coil for canceling leakage magnetic flux in a state where power is transmitted to the power reception coil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power transmission device of Patent Document 1, no consideration is given to canceling leakage magnetic flux according to the surrounding environment.

[0005] An object of the present disclosure is to provide a power transmission device, a power reception device, and a system capable of canceling magnetic flux according to the surrounding environment.

Means for Solving the Problems

[0006] A power transmission device according to an aspect of the present disclosure is a power transmission device capable of wirelessly transmitting power to a power reception device along a power transmission direction, including a power transmission coil, a first power transmission auxiliary coil that is located farther from the power reception device than the power transmission coil in the power transmission direction and has the power transmission coil positioned between the first power transmission auxiliary coil and the power reception device in the power transmission direction, and a second power transmission auxiliary coil that is located outside the power transmission coil in a direction intersecting the power transmission direction. The power transmission device is provided with these components.

[0007] A power receiving device according to one aspect of the present disclosure is a power receiving device capable of wirelessly receiving power transmitted from a power transmitting device along a power transmission direction, including a power receiving coil, a first power receiving auxiliary coil that is located farther from the power transmitting device than the power receiving coil in the power transmission direction and has the power receiving coil located therebetween and the power transmitting device in the power transmission direction, and a second power receiving auxiliary coil that is located outside the power receiving coil in a direction intersecting the power transmission direction and includes.

[0008] A system according to one aspect of the present disclosure is a power transmitting device, and a power receiving device capable of wirelessly receiving power transmitted from the power transmitting device along a power transmission direction and includes, wherein the power transmitting device includes a power transmitting coil, a first power transmitting auxiliary coil that is located farther from the power receiving device than the power transmitting coil in the power transmission direction and has the power transmitting coil located therebetween and the power receiving device in the power transmission direction, and a second power transmitting auxiliary coil that is located outside the power transmitting coil in a direction intersecting the power transmission direction and includes, wherein the power receiving device includes a power receiving coil, a first power receiving auxiliary coil that is located farther from the power transmitting device than the power receiving coil in the power transmission direction and has the power receiving coil located therebetween and the power transmitting device in the power transmission direction, and a second power receiving auxiliary coil that is located outside the power receiving coil in a direction intersecting the power transmission direction and includes.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to realize a power transmitting device, a power receiving device, and a system capable of canceling magnetic flux according to the surrounding environment.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

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Figure 10

Figure 11

Figure 12

Figure 13

Modes for Carrying Out the Invention

[0011] Hereinafter, an example of the present disclosure will be described with reference to the accompanying drawings. The following description is merely illustrative in nature and does not limit the present disclosure, its applications, and its uses. The accompanying drawings are schematic drawings, and the illustrated configurations and actual products may have different ratios of dimensions and the like.

[0012] (First Embodiment) As shown in FIG. 1, the system 1 according to the first embodiment of the present disclosure includes a power transmission device 10 and a power reception device 20. The power transmission device 10 is configured to wirelessly transmit power along a power transmission direction (for example, the Z direction) to the power reception device 20. The power reception device 20 is configured to receive power wirelessly transmitted from the power transmission device 10 along the power transmission direction Z. The system 1 can adopt any wireless power supply method.

[0013] As shown in FIG. 1, the power transmission device 10 includes a power transmission coil 11, a first power transmission auxiliary coil 12, and a second power transmission auxiliary coil 13. The power transmission coil 11 is configured to supply wireless power to the power reception coil 21.

[0014] As shown in FIG. 1, the power reception device 20 includes a power reception coil 21, a first power reception auxiliary coil 22, and a second power reception auxiliary coil 23. The power reception coil 21 is configured to receive wireless power supplied from the power transmission coil 11. The wireless power received by the power reception coil 21 is supplied to, for example, a battery (not shown) connected to the power reception coil 21.

[0015] In the present embodiment, current is supplied from a power source (for example, a current source or a voltage source) 30 to the power transmission coil 11, the first power transmission auxiliary coil 12, and the second power transmission auxiliary coil 13. Current is supplied from a power source (for example, a current source or a voltage source) 40 to the first power reception auxiliary coil 22 and the second power reception auxiliary coil 23. As shown in FIG. 2, the power source 30 includes a power source 31 that supplies current to the first power transmission auxiliary coil 12 and a power source 32 that supplies current to the second power transmission auxiliary coil 13. The power source 40 includes a power source 41 that supplies current to the first power reception auxiliary coil 22 and a power source 42 that supplies current to the second power reception auxiliary coil 23.

[0016] As shown in FIGS. 2 and 3, as an example, the power transmission coil 11 is annular (for example, an annular shape with a polygonal diameter including a quadrilateral, and a circular annular shape including a perfect circle and an ellipse), and has a coil axis L1 extending along the power transmission direction Z. The power transmission coil 11 is formed of, for example, Litz wire or copper wire.

[0017] The first power transmission auxiliary coil 12 is, as an example, annular and substantially the same as the power transmission coil 11, and is located around the coil axis L1 of the power transmission coil 11. The first power transmission auxiliary coil 12 is formed of, for example, a litz wire or a copper wire. The first power transmission auxiliary coil 12 is positioned such that the power transmission coil 11 is located between it and the power receiving device 20 in the power transmission direction Z. In the present embodiment, the first power transmission auxiliary coil 12 is located substantially coaxially with the coil axis L1 of the power transmission coil 11, but is not limited thereto.

[0018] The second power transmission auxiliary coil 13 is, as an example, annular and larger than the power transmission coil 11, and is located around the coil axis L1 of the power transmission coil 11. The second power transmission auxiliary coil 13 is formed of, for example, a litz wire or a copper wire. The second power transmission auxiliary coil 13 is located outside the power transmission coil 11 in a direction (for example, the X direction) intersecting the power transmission direction Z. In the present embodiment, as shown in FIG. 3, the second power transmission auxiliary coil 13 is located along a center line CL1 that passes through the center of the power transmission coil 11 in the power transmission direction Z and extends in a direction intersecting the power transmission direction Z, but is not limited thereto.

[0019] As shown in FIGS. 2 and 3, the power receiving coil 21 is, as an example, annular (for example, square annular or circular annular) and has a coil axis L2 extending along the power transmission direction Z. The power receiving coil 21 is formed of, for example, a litz wire or a copper wire. In the present embodiment, the coil axis L2 of the power receiving coil 21 is located substantially coaxially with the coil axis L1 of the power transmission coil 11, but is not limited thereto.

[0020] The first power receiving auxiliary coil 22 is, as an example, annular and substantially the same as the power receiving coil 21, and is located around the coil axis L2 of the power receiving coil 21. The first power receiving auxiliary coil 22 is formed of, for example, a litz wire or a copper wire. The first power receiving auxiliary coil 22 is positioned such that the power receiving coil 21 is located between it and the power transmission device 10 in the power transmission direction Z. In the present embodiment, the first power receiving auxiliary coil 22 is located substantially coaxially with the coil axis L2 of the power receiving coil 21, but is not limited thereto.

[0021] As an example, the second power receiving auxiliary coil 23 is annular and larger than the power receiving coil 21, and is positioned around the coil axis L2 of the power receiving coil 21. The second power receiving auxiliary coil 21 is formed of, for example, Litz wire or copper wire. The second power receiving auxiliary coil 23 is located outside the power receiving coil 21 in a direction intersecting the power transmission direction Z. In the present embodiment, as shown in FIG. 3, the second power receiving auxiliary coil 23 is positioned along a center line CL2 that passes through the center of the power receiving coil 21 in the power transmission direction Z and extends in a direction intersecting the power transmission direction Z, but is not limited thereto.

[0022] In the present embodiment, the power transmission device 10 and the power receiving device 20 further include control devices 14 and 24. The control devices 14 and 24 include, as an example, processors 141 and 241, storage devices 142 and 242, and communication devices 143 and 243. The processors 141 and 241 and the storage devices 142 and 242 constitute, for example, part of the current control circuit described later. The control device 14 of the power transmission device 10 includes an inverter, and the control device 24 of the power receiving device 20 includes a rectifier circuit.

[0023] The processors 141 and 241 include, for example, a CPU, MPU, GPU, DSP, FPGA, ASIC, or a combination thereof. The storage devices 142 and 242 include non-transitory computer-readable storage media constituted by, for example, internal recording media or external recording media. The internal recording media include non-volatile memories and the like. The external recording media include hard disk drives (HDDs), solid state drives (SSDs), optical disk devices, and the like. The communication devices 143 and 243 are constituted by, for example, communication circuits or communication modules for transmitting and receiving data to and from external devices such as servers, portable terminal devices such as smartphones and tablets, or external input devices such as remote controllers (remote operation devices).

[0024] The control device 14 of the power transmission device 10 is configured to be able to control at least one of the first current flowing through the first power transmission auxiliary coil 12 and the second current flowing through the second power transmission auxiliary coil 13. In the present embodiment, the control device 14 is configured to be able to control both the first current and the second current, the switches 33, 34 (shown in FIG. 2), and the current flowing through the power transmission coil 11. The directions of the first current and the second current are controlled by a current control circuit included in the control device 14. The on / off of the first current and the second current is controlled by the switches 33, 34. The current flowing through the power transmission coil 11 is not limited to being controlled by the control device 14, and may be controlled by an external device, for example.

[0025] The control device 14 is configured to be able to perform at least one of the following processes (1) and (2). · Process (1) The control device 14 controls the first current so that the first current is in phase with the current flowing through the power transmission coil 11, and strengthens the magnetic field (also referred to as leakage magnetic field) in the power transmission direction Z. If a detection target (for example, a shielding object or an operator) exists in the strengthened magnetic field, a specific parameter changes as compared with the case where the detection target does not exist. The control device 14 detects whether a detection target exists in the power transmission direction Z (in other words, whether a detection target exists in a range or region located in the power transmission direction Z with respect to the power transmission device 10) from this change in the parameter. When the presence of the detection target is detected, the control device 14 specifies the range where the detection target exists, and controls the first current so that the first current is out of phase with the current flowing through the power transmission coil 11, thereby suppressing the magnetic field in the power transmission direction Z of the power transmission device 10. · Process (2) The control device 14 controls the second current so as to be in phase with the current flowing through the power transmission coil 11, and strengthens the magnetic field in the direction intersecting the power transmission direction Z. If a detection target exists within the strengthened magnetic field, a specific parameter changes as compared with the case where the detection target does not exist. The control device 14 detects from this change in the parameter whether the detection target exists in the direction intersecting the power transmission direction Z (in other words, whether the detection target exists in the range or region located in the direction intersecting the power transmission direction Z with respect to the power transmission device 10). When detecting the presence of the detection target, the control device 14 specifies the range where the detection target exists, and controls the second current so as to be out of phase with the current flowing through the power transmission coil 11, and suppresses the magnetic field in the direction intersecting the power transmission direction Z of the power transmission device 10.

[0026] By controlling the first current and the second current simultaneously, the presence of the detection target can be detected and the magnetic field can be suppressed in the three-dimensional range around the power transmission device 10. By changing the positions of the first power transmission auxiliary coil 12 and the second power transmission auxiliary coil 13 with respect to the power transmission coil 11, the range of the detection target detectable by each auxiliary coil and the range of the magnetic field suppressible can be set. For example, when the second power transmission auxiliary coil 13 is located between the power transmission coil 11 and the first power transmission auxiliary coil 12 in the power transmission direction Z, the control device 14 can detect whether a detection target exists in the lower right direction and the lower left direction of the power transmission device 10 in FIG. 3, and can suppress the magnetic field in the lower right direction and the lower left direction of the device 10 in FIG. 3.

[0027] The control device 24 of the power reception device 20 is configured to be able to control at least one of the third current flowing through the first power reception auxiliary coil 22 and the fourth current flowing through the second power reception auxiliary coil 23. In the present embodiment, the control device 24 is configured to be able to control both the third current and the fourth current, and the switches 43 and 44 (shown in FIG. 2). The directions of the third current and the fourth current are controlled by a current control circuit included in the control device 24. The on / off of the third current and the fourth current are controlled by the switches 43 and 44.

[0028] The control device 24 is configured to be capable of performing at least one of the following processes (3) and (4). · Process (3) The control device 24 controls the third current so as to be in phase with the current flowing through the power receiving coil 21, thereby strengthening the magnetic field in the power transmission direction Z. If a detection target exists within the strengthened magnetic field, a specific parameter changes as compared with the case where the detection target does not exist. The control device 24 detects whether a detection target exists in the power transmission direction Z (in other words, whether a detection target exists in the range or area located in the power transmission direction Z with respect to the power receiving device 20) from this change in the parameter. When the presence of the detection target is detected, the control device 24 specifies the range in which the detection target exists, and controls the third current so as to be out of phase with the current flowing through the power receiving coil 21, thereby suppressing the magnetic field in the power transmission direction Z of the power receiving device 20. · Process (4) The control device 24 controls the fourth current so as to be in phase with the current flowing through the power receiving coil 21, thereby strengthening the magnetic field in the direction intersecting the power transmission direction Z. If a detection target exists within the strengthened magnetic field, a specific parameter changes as compared with the case where the detection target does not exist. The control device 24 detects whether a detection target exists in the direction intersecting the power transmission direction Z (in other words, whether a detection target exists in the range or area located in the direction intersecting the power transmission direction Z with respect to the power receiving device 20) from this change in the parameter. When the presence of the detection target is detected, the control device 24 specifies the range in which the detection target exists, and controls the fourth current so as to be out of phase with the current flowing through the power receiving coil 21, thereby suppressing the magnetic field in the direction intersecting the power transmission direction Z of the power receiving device 20.

[0029] By controlling the third current and the fourth current simultaneously, the presence of a detection target can be detected and the magnetic field can be suppressed within a three-dimensional range around the power receiving device 20. By changing the positions of the first power receiving auxiliary coil 22 and the second power receiving auxiliary coil 23 with respect to the power receiving coil 21, the range of the detection target detectable by each auxiliary coil and the range of the magnetic field suppressible can be set. For example, when the second power receiving auxiliary coil 23 is located between the power receiving coil 21 and the first power receiving auxiliary coil 22 in the power transmission direction Z, the control device 34 can detect whether a detection target exists in the upper right direction and the upper left direction of the power receiving device 20 in FIG. 3, and can suppress the magnetic fields in the upper right direction and the upper left direction of the power receiving device 20 in FIG. 3.

[0030] In processes (1) to (4), "the first to fourth currents are out of phase with the currents flowing through the power transmission coil 11 or the power receiving coil 21" means, for example, that when viewed along the power transmission direction Z, the direction in which the Nth current flows is opposite to the direction in which the current flows through the power transmission coil 11 or the power receiving coil 21. "The first to fourth currents are in phase with the currents flowing through the power transmission coil 11 or the power receiving coil 21" means, for example, that when viewed along the power transmission direction Z, the direction in which the Nth current flows is the same as the direction in which the current flows through the power transmission coil 11 or the power receiving coil 21.

[0031] In processes (1) to (4), the region where the magnetic field is strengthened is set by the positional relationship between the power transmission coil 11 (or the power receiving coil 21) and each auxiliary coil and the relationship between the current amplitudes supplied to each coil.

[0032] In processes (1) to (4), the specific parameters include, for example, the degree of coupling between the power transmission coil 11 (or the power receiving coil 21) and each auxiliary coil, or the current value flowing through each auxiliary coil, or the input impedance of each auxiliary coil. An example of a method for obtaining the input impedance of each auxiliary coil is shown below. · Assume that the power transmission device 10 or the power reception device 20 is configured to supply a current of a constant amplitude to each auxiliary coil with a constant current source such as an inverter (DC→AC) (see Fig. 2). In this case, the input impedance of each auxiliary coil is obtained from the voltage measured using a voltmeter connected in parallel with each auxiliary coil as seen from the current source and the current flowing through each auxiliary coil. · Assume that the power transmission device 10 or the power reception device 20 is configured to apply a voltage of a constant amplitude to each auxiliary coil with a constant voltage source (see Figs. 5 and 6). In this case, the input impedance of each auxiliary coil is obtained from the change in current measured using an ammeter connected in series with each auxiliary coil and the voltage applied to each auxiliary coil.

[0033] With reference to Fig. 4, an example of the power transmission process of the power transmission device 10 will be described. In the power transmission process of Fig. 4, it is assumed that the control device 14 is configured to be able to perform process (1) and process (2). The power transmission process shown in Fig. 4 is implemented, for example, by the processor 141 executing a predetermined program stored in the storage device 142.

[0034] As shown in Fig. 4, when the power transmission process is started, the control device 14 controls the first current and the second current to cause currents in the first power transmission auxiliary coil 12 and the second power transmission auxiliary coil 13 that are in phase with the current flowing through the power transmission coil 11 (step S1), and strengthens the magnetic fields in the power transmission direction Z and the direction intersecting the power transmission direction Z (step S2).

[0035] When the magnetic field is strengthened, the control device 14 determines whether a detection target exists within a range located in the power transmission direction Z of the power transmission device 10 and the direction intersecting the power transmission direction Z (step S3).

[0036] When it is determined that a detection target exists, the control device 14 specifies the range where the detection target exists (step S4), and selects a power transmission auxiliary coil capable of suppressing the magnetic field in the specified range (step S5). When the power transmission auxiliary coil is selected, the control device 14 causes a current having a phase opposite to that of the current flowing through the power transmission coil 11 to flow through the selected auxiliary coil (step S6), and suppresses the magnetic field in the specified range (step S7).

[0037] If it is not determined in step S3 that a detection target exists, or if the magnetic field in the range specified in step S7 is suppressed, the control device 14 determines whether to end the power transmission process (step S8). The control device 14 determines to end the power transmission process, for example, when the current supply from the power source 30 to the power transmission coil 11 stops, or when it receives an instruction to end the power transmission process via the communication device 143 or the like. If it is not determined to end the power transmission process, the process returns to step S3, and it is determined whether a detection target exists in the range located in the power transmission direction Z of the power transmission device 10 and in the direction intersecting the power transmission direction Z.

[0038] The power transmission process shown in FIG. 4 can also be applied to the power reception process of the power reception device 20 including the control device 24 capable of performing processes (3) and (4).

[0039] The power transmission device 10 of the first embodiment can exhibit the following effects.

[0040] The power transmission device 10 is a power transmission device 10 capable of wirelessly transmitting power to the power reception device 20 along the power transmission direction Z, and includes a power transmission coil 11, a first power transmission auxiliary coil 12, and a second power transmission auxiliary coil 13. The first power transmission auxiliary coil 12 is configured such that the power transmission coil 11 is positioned between it and the power reception device 20 in the power transmission direction Z. The second power transmission auxiliary coil 13 is positioned outside the power transmission coil 11 in the direction intersecting the power transmission direction Z. With such a configuration, a power transmission device 10 capable of canceling magnetic flux according to the surrounding environment can be realized.

[0041] The power transmission device 10 includes a control device 14 capable of controlling a first current flowing through the first power transmission auxiliary coil 12. The control device 14 is configured to control the first current so that the first current is in phase with the current flowing through the power transmission coil 11, and is configured to be able to detect whether a detection target exists in the power transmission direction Z. With such a configuration, the power transmission device 10 capable of canceling magnetic flux according to the surrounding environment can be more reliably realized.

[0042] When the control device 14 detects the presence of a detection target, the control device 14 is configured to control the first current so that the first current is out of phase with the current flowing through the power transmission coil 11, and is configured to be able to suppress the magnetic field in the power transmission direction Z. With such a configuration, the power transmission device 10 capable of canceling magnetic flux according to the surrounding environment can be more reliably realized.

[0043] The power transmission device 10 includes a control device 14 capable of controlling a second current flowing through the second power transmission auxiliary coil 13. The control device 14 is configured to control the second current so that the second current is in phase with the current flowing through the power transmission coil 11, and is configured to be able to detect whether a detection target exists in a direction intersecting the power transmission direction Z. With such a configuration, the power transmission device 10 capable of canceling magnetic flux according to the surrounding environment can be more reliably realized.

[0044] When the control device 14 detects the presence of a detection target, the control device 14 is configured to control the second current so that the second current is out of phase with the current flowing through the power transmission coil 11, and is configured to be able to suppress the magnetic field in a direction intersecting the power transmission direction Z. With such a configuration, the power transmission device 10 capable of canceling magnetic flux according to the surrounding environment can be more reliably realized.

[0045] The power receiving device 20 of the first embodiment can exhibit the following effects.

[0046] The power receiving device 20 is a power receiving device capable of wirelessly receiving power transmitted from the power transmitting device 10 along the power transmission direction Z, and includes a power receiving coil 21, a first power receiving auxiliary coil 22, and a second power receiving auxiliary coil 23. The first power receiving auxiliary coil 22 is configured such that the power receiving coil 20 is positioned between it and the power transmitting device 10 in the power transmission direction Z. The second power receiving auxiliary coil 23 is positioned outside the power receiving coil 21 in a direction intersecting the power transmission direction Z. With such a configuration, a power receiving device 20 capable of canceling magnetic flux according to the surrounding environment can be realized.

[0047] The power receiving device 20 includes a control device 24 capable of controlling a third current flowing through the first power receiving auxiliary coil 22. The control device 24 is configured to control the third current so that it is in phase with the current flowing through the power receiving coil 21, enabling detection of whether a detection target exists in the power transmission direction Z. With such a configuration, a power receiving device 20 capable of canceling magnetic flux according to the surrounding environment can be realized more reliably.

[0048] When the control device 24 detects the presence of a detection target, it is configured to control the third current so that it is out of phase with the current flowing through the power receiving coil 21, suppressing the magnetic field in the power transmission direction Z. With such a configuration, a power receiving device 20 capable of canceling magnetic flux according to the surrounding environment can be realized more reliably.

[0049] The power receiving device 20 includes a control device 24 capable of controlling a fourth current flowing through the second power receiving auxiliary coil 23. The control device 24 is configured to control the fourth current so that it is in phase with the current flowing through the power receiving coil 21, enabling detection of whether a detection target exists in a direction intersecting the power transmission direction Z. With such a configuration, a power receiving device 20 capable of canceling magnetic flux according to the surrounding environment can be realized more reliably.

[0050] When the control device 24 detects the presence of the detection target, the control device 24 controls the fourth current so as to be opposite in phase to the current flowing through the power receiving coil 21, and is configured to suppress the magnetic field in the direction intersecting the power transmission direction Z. With such a configuration, the power receiving device 20 capable of canceling the magnetic flux according to the surrounding environment can be more reliably realized.

[0051] The system 1 of the first embodiment can exhibit the following effects.

[0052] The system 1 includes a power transmission device 10 and a power receiving device 20 capable of receiving power wirelessly transmitted from the power transmission device 10 along the power transmission direction Z. The power transmission device 10 includes a power transmission coil 11, a first power transmission auxiliary coil 12, and a second power transmission auxiliary coil 13. The first power transmission auxiliary coil 12 is configured such that the power transmission coil 11 is positioned between the power transmission device 10 and the power receiving device 20 in the power transmission direction Z. The second power transmission auxiliary coil 13 is positioned outside the power transmission coil 11 in the direction intersecting the power transmission direction Z. The power receiving device 20 includes a power receiving coil 21, a first power receiving auxiliary coil 22, and a second power receiving auxiliary coil 23. The first power receiving auxiliary coil 22 is configured such that the power receiving coil 20 is positioned between the power receiving device 20 and the power transmission device 10 in the power transmission direction Z. The second power receiving auxiliary coil 23 is positioned outside the power receiving coil 21 in the direction intersecting the power transmission direction Z. With such a configuration, the system 1 capable of canceling the magnetic flux according to the surrounding environment can be realized.

[0053] The system 1, the power transmission device 10, and the power receiving device 20 of the first embodiment can be configured as follows.

[0054] The first current, the second current, the third current, and the fourth current are not limited to being controlled by the current control circuit. For example, as shown in FIG. 5, variable capacitors 35, 36, 45, and 46 are connected in series to each auxiliary coil to form a circuit, and by changing the capacitance of the variable capacitors 35, 36, 45, and 46, the directions of the first current, the second current, the third current, and the fourth current can be controlled. By setting the capacitance of the variable capacitors 35, 36, 45, and 46 to a value smaller than that in the resonant state, the magnetic field formed by each auxiliary coil and the magnetic field formed by the power transmission coil 11 or the power reception coil 21 become in phase, and it becomes possible to strengthen the magnetic field. On the other hand, by setting the capacitance of the variable capacitors 35, 36, 45, and 46 to a value larger than that in the resonant state, the magnetic field formed by each auxiliary coil and the magnetic field formed by the power transmission coil 11 or the power reception coil 21 become out of phase, and it becomes possible to suppress the magnetic field.

[0055] In the system 1 of FIG. 5, instead of the circuit including the variable capacitors 35, 36, 45, and 46, the circuit shown in FIG. 6 can be used. The circuit shown in FIG. 6 includes two capacitors 51, 52 and two switches 61, 62, and by controlling the two switches 61, 62, the capacitors 51, 52 connected to each auxiliary coil can be switched.

[0056] As shown in FIG. 7, in addition to the first power transmission auxiliary coil 12 and the second power transmission auxiliary coil 13, the power transmission device 10 can include a third power transmission auxiliary coil 15 and a fourth power transmission auxiliary coil 16. The third power transmission auxiliary coil 15 is configured such that the first power transmission auxiliary coil 12 is positioned between the third power transmission auxiliary coil 15 and the power transmission coil 11 in the power transmission direction Z. The fourth power transmission auxiliary coil 16 is positioned outside the second power transmission auxiliary coil 13 in a direction intersecting the power transmission direction Z. By configuring in this way, the range of the magnetic field that can be strengthened and suppressed becomes wider. The power transmission device 10 may include only one of the third power transmission auxiliary coil 15 and the fourth power transmission auxiliary coil 16. The power transmission device 10 may include a power transmission auxiliary coil in which the third power transmission auxiliary coil 15 is positioned between the first power transmission auxiliary coil 12 and the power transmission direction Z. The power transmission device 10 may include a power transmission auxiliary coil positioned outside the fourth power transmission auxiliary coil 16 in a direction intersecting the power transmission direction Z. The current flowing through all the power transmission auxiliary coils is controlled by, for example, the control device 14.

[0057] As shown in FIG. 7, similar to the power transmission device 10, the power reception device 20 can also include a third power reception auxiliary coil 25 and a fourth power reception auxiliary coil 26. The third power reception auxiliary coil 25 is configured such that the first power reception auxiliary coil 22 is positioned between the third power reception auxiliary coil 25 and the power reception coil 21 in the power transmission direction Z. The fourth power reception auxiliary coil 26 is positioned outside the second power reception auxiliary coil 23 in a direction intersecting the power transmission direction Z. By configuring in this way, the range of the magnetic field that can be strengthened and suppressed becomes wider. The power reception device 20 may include only one of the third power reception auxiliary coil 25 and the fourth power reception auxiliary coil 26. The power reception device 20 may include a power reception auxiliary coil in which the third power reception auxiliary coil 25 is positioned between the first power reception auxiliary coil 22 and the power transmission direction Z. The power reception device 20 may include a power reception auxiliary coil positioned outside the fourth power reception auxiliary coil 26 in a direction intersecting the power transmission direction Z. The current flowing through all the power reception auxiliary coils is controlled by, for example, the control device 14.

[0058] The power transmission device 10 and the power reception device 20 are not limited to being configured as a single device including the control devices 14 and 24. For example, the control devices 14 and 24 may be distributed among any number of networked computers, or may be provided in each of any number of networked computers. That is, the control devices 14 and 24 may or may not form part of the power transmission device 10 and the power reception device 20.

[0059] The power supplies 30 and 40 may or may not form part of the power transmission device 10 and the power reception device 20.

[0060] The power transmission device 10 may include a power transmission core 18 located between the power transmission coil 11 and the first power transmission auxiliary coil 12 in the power transmission direction Z (see FIGS. 8 and 9). Similarly, the power reception device 20 may also include a power reception core 28 located between the power reception coil 21 and the first power reception auxiliary coil 22 in the power transmission direction Z (see FIGS. 8 to 11).

[0061] The first embodiment of the present disclosure will be described below with reference numerals attached.

[0062] The power transmission device 10 according to the first aspect of the first embodiment is a power transmission device 10 capable of wirelessly transmitting power transmitted along the power transmission direction to the power reception device 20, a power transmission coil 11, a first power transmission auxiliary coil 12 located between the power transmission coil 11 and the power reception device 20 in the power transmission direction, and a second power transmission auxiliary coil 13 located outside the power transmission coil 11 in a direction intersecting the power transmission direction and includes.

[0063] The power transmission device 10 according to the second aspect of the first embodiment is the power transmission device 10 according to the first aspect, and includes a third power transmission auxiliary coil 15 located between the first power transmission auxiliary coil 12 and the power transmission coil 11 in the power transmission direction.

[0064] The power transmission device 10 according to the third aspect of the first embodiment is the power transmission device 10 according to the first aspect or the second aspect, and includes a fourth power transmission auxiliary coil 16 located outside the second power transmission auxiliary coil 13 in a direction intersecting the power transmission direction.

[0065] The power transmission device 10 according to the fourth aspect of the first embodiment is the power transmission device 10 according to any one of the first aspect to the third aspect, and includes a control device 14 capable of controlling a first current flowing through the first power transmission auxiliary coil 12. The control device 14 is configured to control the first current so that the first current is in phase with the current flowing through the power transmission coil 11, and to be able to detect whether a detection target exists in the power transmission direction.

[0066] The power transmission device 10 according to the fifth aspect of the first embodiment is the power transmission device 10 according to the fourth aspect, and when the control device 14 detects the presence of the detection target, the control device 14 is configured to control the first current so that the first current is out of phase with the current flowing through the power transmission coil 11, and to be able to suppress the magnetic field in the power transmission direction.

[0067] The power transmission device 10 according to the sixth aspect of the first embodiment is the power transmission device 10 according to any one of the first aspect to the fifth aspect, and includes a control device 14 capable of controlling a second current flowing through the second power transmission auxiliary coil 13. The control device 14 is configured to control the second current so that the second current is in phase with the current flowing through the power transmission coil 11, and to be able to detect whether a detection target exists in a direction intersecting the power transmission direction.

[0068] The power transmission device 10 according to the seventh aspect of the first embodiment is the power transmission device 10 according to the sixth aspect, and when the control device 14 detects the presence of the detection target, the control device 14 is configured to control the second current so that the second current is out of phase with the current flowing through the power transmission coil 11, and to be able to suppress the magnetic field in a direction intersecting the power transmission direction.

[0069] The power receiving device 20 according to the eighth aspect of the first embodiment is a power receiving device 20 capable of wirelessly receiving power transmitted from the power transmitting device 10 along the power transmission direction, including a power receiving coil 21, a first power receiving auxiliary coil 22 located between the power receiving coil 21 and the power transmitting device 10 in the power transmission direction, and a second power receiving auxiliary coil 23 located outside the power receiving coil 21 in a direction intersecting the power transmission direction. It is provided with.

[0070] The power receiving device 20 according to the ninth aspect of the first embodiment is the power receiving device 20 according to the eighth aspect, in which a third power receiving auxiliary coil 25 is provided, in which the first power receiving auxiliary coil 22 is located between the power receiving coil 21 and the power transmitting device 10 in the power transmission direction.

[0071] The power receiving device 20 according to the tenth aspect of the first embodiment is the power receiving device 20 according to the eighth or ninth aspect, in which a fourth power receiving auxiliary coil 26 is provided, which is located outside the second power receiving auxiliary coil 23 in a direction intersecting the power transmission direction.

[0072] The power receiving device 20 according to the eleventh aspect of the first embodiment is the power receiving device 20 according to any one of the eighth to tenth aspects, in which a control device 24 capable of controlling a third current flowing through the first power receiving auxiliary coil 22 is provided, and the control device 24 is configured to control the third current so that the third current is in phase with the current flowing through the power receiving coil 21, and to be able to detect whether a detection target exists in the power transmission direction.

[0073] The power receiving device 20 according to the twelfth aspect of the first embodiment is the power receiving device 20 according to the eleventh aspect, in which when the control device 24 detects the existence of the detection target, the control device 24 controls the third current so that the third current is out of phase with the current flowing through the power receiving coil 21, and is configured to suppress the magnetic field in the power transmission direction.

[0074] The power receiving device 20 according to the 13th aspect of the first embodiment is the power receiving device 20 according to any one of the 8th to 12th aspects, and includes a control device 24 capable of controlling a fourth current flowing through the second power receiving auxiliary coil 23. The control device 24 is configured to control the fourth current so that the fourth current is in phase with the current flowing through the power receiving coil 21, and to be able to detect whether or not there is a detection target in a direction intersecting the power transmission direction.

[0075] The power receiving device 20 according to the 14th aspect of the first embodiment is the power receiving device 20 according to the 13th aspect, and when the control device 24 detects the presence of the detection target, the control device 24 is configured to control the fourth current so that the fourth current is out of phase with the current flowing through the power receiving coil 21, and to suppress a magnetic field in a direction intersecting the power transmission direction.

[0076] The system 1 according to the 15th aspect of the first embodiment includes a power transmission device 10 and a power receiving device 20 capable of wirelessly receiving power transmitted from the power transmission device 10 along a power transmission direction. The power transmission device 10 includes a power transmission coil 11, a first power transmission auxiliary coil 12 positioned between the power transmission coil 11 and the power receiving device 20 in the power transmission direction, and a second power transmission auxiliary coil 13 positioned outside the power transmission coil 11 in a direction intersecting the power transmission direction. The power receiving device 20 includes a power receiving coil 21, a first power receiving auxiliary coil 22 positioned between the power receiving coil 21 and the power transmission device 10 in the power transmission direction, and a second power receiving auxiliary coil 23 positioned outside the power receiving coil 21 in a direction intersecting the power transmission direction.

[0077] (Second Embodiment) As shown in FIGS. 8 and 9, the power transmission device 10 of the system 1 according to the second embodiment includes a power transmission coil 11, a first power transmission auxiliary coil 12 (an example of a power transmission auxiliary coil), and a first shield member 17. In the present embodiment, the power transmission device 10 further includes a power transmission core 18. The power reception device 20 of the system 1 according to the second embodiment includes a power reception coil 21, a first power reception auxiliary coil 22 (an example of a power reception auxiliary coil), and a second shield member 27. In the present embodiment, the power reception device 20 further includes a power reception core 28.

[0078] As shown in FIG. 9, the first shield member 17 of the power transmission device 10 is positioned farther from the power reception device 20 than the power transmission coil 11 in the power transmission direction Z, and the power transmission coil 11 is positioned between the first shield member 17 and the power reception device 20 in the power transmission direction Z. The first power transmission auxiliary coil 12 is positioned between the power transmission coil 11 and the first shield member 17 in the power transmission direction Z.

[0079] In the present embodiment, the first shield member 17 includes a substantially rectangular plate-shaped first member 171 and a first magnetic member 173. The first member 171 is formed of, for example, a non-magnetic conductor (e.g., aluminum or copper). The first magnetic member 173 is formed of, for example, ferrite. The first magnetic member 173 is provided at a portion of the first member 171 that faces the power transmission coil 11 in the power transmission direction Z and at both end portions in a direction (e.g., the X direction) intersecting the power transmission direction Z of the first member 171, but is not limited thereto. The first magnetic member 173 may be provided at at least a part of the portion of the first member 171 that faces the power transmission coil 11 in the power transmission direction Z.

[0080] As shown in FIG. 9, the power transmission core 18 is located between the power transmission coil 11 and the first power transmission auxiliary coil 12 in the power transmission direction Z. The power transmission core 18 is formed of a magnetic material such as ferrite, for example. As shown in FIGS. 8 and 9, the power transmission core 18 includes a first main body portion 181 configured to overlap the power transmission coil 11 when viewed along the power transmission direction Z. In the present embodiment, the first main body portion 181 has a substantially rectangular plate shape and is formed of a magnetic material such as ferrite. The first main body portion 181 is configured such that the power transmission coil 11 is located inside the outer contour line of the power transmission core 18 when viewed along the power transmission direction Z. As an example, the first main body portion 181 has substantially the same shape and size as the first shield member 17.

[0081] In the power transmission direction Z, gaps are formed between the power transmission coil 11 and the power transmission core 18, between the power transmission core 18 and the first power transmission auxiliary coil 12, and between the first power transmission auxiliary coil 12 and the first shield member 17. The size of the gap can be changed, for example, in units of mm (millimeters). By increasing the gap, the effect of suppressing shield loss can be easily obtained. The gap may be filled with a material such as resin.

[0082] As shown in FIG. 9, the second shield member 27 of the power reception device 20 is located farther from the power transmission device 10 than the power reception coil 21 in the power transmission direction Z, and the power reception coil 21 is located between the second shield member 27 and the power transmission device 10 in the power transmission direction Z. The first power reception auxiliary coil 22 is located between the power reception coil 21 and the second shield member 27 in the power transmission direction Z.

[0083] In this embodiment, the second shielding member 27 includes a substantially rectangular plate-shaped third member 271 and a second magnetic member 273. The third member 271 is formed of, for example, a non-magnetic conductor (e.g., aluminum or copper). The second magnetic member 273 is provided at a portion of the third member 271 that faces the power receiving coil 21 in the power transmission direction Z and at both end portions in a direction (e.g., the X direction) intersecting the power transmission direction Z of the third member 271, but is not limited thereto. The second magnetic member 273 may be provided at at least a part of the portion of the third member 271 that faces the power receiving coil 21 in the power transmission direction Z.

[0084] As shown in FIG. 9, the power receiving core 28 is located between the power receiving coil 21 and the first power receiving auxiliary coil 22 in the power transmission direction Z. The power receiving core 28 is formed of, for example, a magnetic material such as ferrite. As shown in FIGS. 8 and 9, the power receiving core 28 includes a second main body portion 281 configured to overlap the power receiving coil 21 when viewed along the power transmission direction Z. In this embodiment, the second main body portion 281 has a substantially rectangular plate shape and is formed of a magnetic material such as ferrite. The second main body portion 281 is configured such that the power receiving coil 21 is located inside the outer contour line of the power receiving core 28 when viewed along the power transmission direction Z. As an example, the second main body portion 281 has substantially the same shape and size as the second shielding member 27.

[0085] In the power transmission direction Z, gaps are formed between the power receiving coil 21 and the power receiving core 28, between the power receiving core 28 and the first power receiving auxiliary coil 22, and between the first power receiving auxiliary coil 22 and the second shielding member 27. The size of the gap can be changed, for example, in units of mm. By increasing the gap, the effect of suppressing shield loss can be easily obtained. The gap may be filled with a material such as resin.

[0086] The power transmission device 10 of the second embodiment can exhibit the following effects.

[0087] The power transmission device 10 is a power transmission device 10 capable of wirelessly transmitting power along the power transmission direction Z to the power reception device 20, and includes a power transmission coil 11, a first shield member 17, and a first power transmission auxiliary coil 12. The first shield member 17 is positioned farther from the power reception device 20 than the power transmission coil 11 in the power transmission direction Z, and is configured such that the power transmission coil 11 is positioned between the first shield member 17 and the power reception device 20 in the power transmission direction Z. The first power transmission auxiliary coil 12 is positioned between the power transmission coil 11 and the first shield member 17 in the power transmission direction Z. With such a configuration, for example, by making the current flowing through the first power transmission auxiliary coil 12 opposite in phase to the current flowing through the power transmission coil 11, the magnetic field incident on the first shield member 17 is suppressed. As a result, it is possible to realize the power transmission device 10 that can suppress the shield loss caused by the eddy current generated when the magnetic field is incident on the first shield member 17.

[0088] The first shield member 17 includes a first magnetic member 173 provided in a portion facing the power transmission coil 11 in the power transmission direction Z. With such a configuration, it is possible to realize the power transmission device 10 that can more reliably suppress the shield loss.

[0089] The power reception device 20 of the second embodiment can exhibit the following effects.

[0090] The power reception device 20 is a power reception device 20 capable of receiving power wirelessly transmitted along the power transmission direction Z from the power transmission device 10, and includes a power reception coil 21, a second shield member 27, and a first power reception auxiliary coil 22. The second shield member 27 is positioned farther from the power transmission device 10 than the power reception coil 21 in the power transmission direction Z, and is configured such that the power reception coil 21 is positioned between the second shield member 27 and the power transmission device 10 in the power transmission direction Z. The first power reception auxiliary coil 22 is positioned between the power reception coil 21 and the second shield member 27 in the power transmission direction Z. With such a configuration, for example, by making the current flowing through the first power reception auxiliary coil 22 opposite in phase to the current flowing through the power reception coil 21, the magnetic field incident on the second shield member 27 is suppressed. As a result, it is possible to realize the power reception device 20 that can suppress the shield loss caused by the eddy current generated when the magnetic field is incident on the second shield member 27.

[0091] The second shielding member 27 includes a second magnetic member 273 provided at a portion facing the power receiving coil 21 in the power transmission direction Z. With such a configuration, a power receiving device 20 capable of more reliably suppressing shielding loss can be realized.

[0092] The system 1 of the second embodiment can exhibit the following effects.

[0093] The system 1 includes a power transmission device 10 and a power receiving device 20 capable of receiving power wirelessly transmitted along the power transmission direction Z from the power transmission device 10. The power transmission device 10 includes a power transmission coil 11, a first shielding member 17, and a first power transmission auxiliary coil 12. The first shielding member 17 is positioned farther from the power receiving device 20 than the power transmission coil 11 in the power transmission direction Z, and is configured such that the power transmission coil 11 is positioned between the first shielding member 17 and the power receiving device 20 in the power transmission direction Z. The first power transmission auxiliary coil 12 is positioned between the power transmission coil 11 and the first shielding member 17 in the power transmission direction Z. The power receiving device 20 includes a power receiving coil 21, a second shielding member 27, and a first power receiving auxiliary coil 22. The second shielding member 27 is positioned farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction Z, and is configured such that the power receiving coil 21 is positioned between the second shielding member 27 and the power transmission device 10 in the power transmission direction Z. The first power receiving auxiliary coil 22 is positioned between the power receiving coil 21 and the second shielding member 27 in the power transmission direction Z. With such a configuration, a system 1 capable of suppressing shielding loss caused by eddy currents generated when a magnetic field is incident on the first shielding member 17 and / or the second shielding member 27 can be realized.

[0094] The system 1, the power transmission device 10, and the power receiving device 20 of the second embodiment can be configured as follows.

[0095] As shown in FIGS. 10 and 11, the power transmission core 18 may include a first protruding portion 182 that protrudes from the first main body portion 181 in the power transmission direction Z. The first protruding portion 182 is located outside the power transmission coil 11 in a direction intersecting the power transmission direction Z, and extends from the first main body portion 181 in the power transmission direction Z and in a direction approaching the power transmission coil 11. In the system 1 of FIGS. 10 and 11, the first protruding portion 182 surrounds the power transmission coil 11 around the power transmission direction Z over the entire circumference of the power transmission coil 11, but is not limited thereto. The power transmission core 18 may be configured such that the first protruding portion 182 surrounds a part of the power transmission coil 11, or the first protruding portion 182 intermittently surrounds the periphery of the power transmission coil 11.

[0096] The power reception core 28 can also be configured in the same manner as the power transmission core 18. That is, the power reception core 28 may include a second protruding portion 282 that protrudes from the second main body portion 281 in the power transmission direction Z. The second protruding portion 282 is located outside the power reception coil 21 in a direction intersecting the power transmission direction Z, and extends from the second main body portion 281 in the power transmission direction Z and in a direction approaching the power reception coil 21. In the system 1 of FIGS. 10 and 11, the second protruding portion 282 surrounds the power reception coil 21 around the power transmission direction Z over the entire circumference of the power reception coil 21, but is not limited thereto. The power reception core 28 may be configured such that the second protruding portion 282 surrounds a part of the power reception coil 21, or the second protruding portion 282 intermittently surrounds the periphery of the power reception coil 21.

[0097] The power transmission device 10 is not limited to the case of including only the first power transmission auxiliary coil 12, and may include a plurality of power transmission auxiliary coils. The plurality of power transmission auxiliary coils are arranged, for example, between the power transmission coil 11 and the first shield member 17 in the power transmission direction Z and / or outside the power transmission coil 11 in a direction intersecting the power transmission direction Z. Similarly, the power reception device 20 is not limited to the case of including only the first power reception auxiliary coil 22, and may include a plurality of power reception auxiliary coils. The plurality of power reception auxiliary coils are arranged, for example, between the power reception coil 21 and the second shield member 27 in the power transmission direction Z and / or outside the power reception coil 21 in a direction intersecting the power transmission direction Z.

[0098] The power transmission device 10 can include a control device 14 capable of controlling the current flowing through the first power transmission auxiliary coil 12. Similarly, the power reception device 20 can include a control device 24 capable of controlling the current flowing through the first power reception auxiliary coil 22.

[0099] The power transmission core 18 and the power reception core 28 can be omitted.

[0100] The first shielding member 17 and the second shielding member 27, and the power transmission core 18 and the power reception core 28 can be applied to the power transmission device 10 and the power reception device 20 of the first embodiment. The power transmission core 18 and the power reception core 28 can be applied to the power transmission device 10 and the power reception device 20 of the third embodiment.

[0101] A second embodiment of the present disclosure will be described below with reference numerals attached.

[0102] The power transmission device 10 of the first aspect of the second embodiment is a power transmission device capable of wirelessly transmitting power along a power transmission direction to the power reception device 20, including a power transmission coil 11, a first shielding member 17 that is located farther from the power reception device 20 than the power transmission coil 11 in the power transmission direction and has the power transmission coil 11 positioned therebetween and the power reception device 20 in the power transmission direction, and a power transmission auxiliary coil positioned between the power transmission coil 11 and the first shielding member 17 in the power transmission direction and including the same.

[0103] The power transmission device 10 of the second aspect of the second embodiment is the power transmission device 10 of the first aspect, and includes a power transmission core 18 positioned between the power transmission coil 11 and the power transmission auxiliary coil in the power transmission direction, wherein the power transmission core 18 includes a first main body portion 181 configured to overlap the power transmission coil 11 when viewed along the power transmission direction, It is located outside the power transmission coil 11 in a direction intersecting the power transmission direction, and includes a first protruding portion 182 that extends from the first main body portion 181 in the power transmission direction and toward the power transmission coil 11. and includes.

[0104] The power transmission device 10 according to the third aspect of the second embodiment is the power transmission device 10 according to the first aspect or the second aspect, wherein the first shielding member 17 includes a first magnetic member 173 provided at a portion facing the power transmission coil 11 in the power transmission direction.

[0105] The power receiving device 20 according to the fourth aspect of the second embodiment is a power receiving device 20 capable of wirelessly receiving power transmitted along the power transmission direction from the power transmission device 10, including a power receiving coil 21, a second shielding member 27 that is located farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction and has the power receiving coil 21 positioned therebetween in the power transmission direction between the power transmission device 10 and the second shielding member 27, and a power receiving auxiliary coil positioned between the power receiving coil 21 and the second shielding member 27 in the power transmission direction. and is provided with.

[0106] The power receiving device 20 according to the fifth aspect of the second embodiment is the power receiving device 20 according to the fourth aspect, and includes a power receiving core 28 positioned between the power receiving coil 21 and the power receiving auxiliary coil in the power transmission direction, wherein the power receiving core 28 includes a second main body portion 281 configured to overlap the power receiving coil 21 when viewed along the power transmission direction, and a second protruding portion 282 that is located outside the power receiving coil 21 in a direction intersecting the power transmission direction and extends from the second main body portion 281 in the power transmission direction and toward the power receiving coil 21. and includes.

[0107] The power receiving device 20 according to the sixth aspect of the second embodiment is the power receiving device 20 according to the fourth aspect or the fifth aspect, The second shielding member 27 includes a second magnetic member 273 provided at a portion facing the power receiving coil 21 in the power transmission direction.

[0108] The system 1 according to the seventh aspect of the second embodiment includes a power transmission device 10 and a power receiving device 20 capable of receiving power wirelessly transmitted along the power transmission direction from the power transmission device 10. The power transmission device 10 includes a power transmission coil 11, a first shielding member 17 that is located farther from the power receiving device 20 than the power transmission coil 11 in the power transmission direction and has the power transmission coil 11 positioned therebetween in the power transmission direction with respect to the power receiving device 20, and a power transmission auxiliary coil positioned between the power transmission coil 11 and the first shielding member 17 in the power transmission direction. The power receiving device 20 includes a power receiving coil 21, a second shielding member 27 that is located farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction and has the power receiving coil 21 positioned therebetween in the power transmission direction with respect to the power transmission device 10, and a power receiving auxiliary coil positioned between the power receiving coil 21 and the second shielding member 27 in the power transmission direction. The power receiving device 20 includes a power receiving coil 21, a second shielding member 27 that is located farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction and has the power receiving coil 21 positioned therebetween in the power transmission direction with respect to the power transmission device 10,

[0109] (Third Embodiment) As shown in FIGS. 12 and 13, the power transmission device 10 of the system 1 according to the third embodiment includes a power transmission coil 11, a first shielding member 17, and a power transmission core 18. The first shielding member 17 is configured to be located farther from the power receiving device 20 than the power transmission coil 11 in the power transmission direction Z and to have the power transmission coil 11 positioned therebetween in the power transmission direction Z with respect to the power receiving device 20. The power transmission core 18 is positioned between the power transmission coil 11 and the first shielding member 17 in the power transmission direction Z.

[0110] The first shield member 17 includes a first member 171, a second member 172, and a first magnetic member 173.

[0111] The first member 171 is configured to overlap the power transmission core 18 when viewed along the power transmission direction Z. In the present embodiment, the first member 171 has a substantially rectangular plate shape and is formed of, for example, a non-magnetic material (e.g., aluminum or copper). The first member 171 is configured such that when viewed along the power transmission direction Z, the power transmission core 18 is located inside the outer contour line of the first member 171.

[0112] The second member 172 is located outside the power transmission core 18 in a direction intersecting the power transmission direction Z and extends from the first member 171 in the power transmission direction Z and in a direction approaching the power transmission core 18. In the present embodiment, the second member 172 is formed of, for example, a non-magnetic material (e.g., aluminum or copper). The second member 172 extends from the first member 171 to the portion facing the power receiving device 20 of the power transmission coil 11, but is not limited thereto. The second member 172 may be configured to extend from the first member 171 to a position closer to the power receiving device 20 than the power transmission coil 11, or may be configured to extend from the first member 171 to a position farther from the power receiving device 20 than the power transmission coil 11. The second member 172 surrounds the power transmission coil 11 and the power transmission core 18 around the power transmission direction Z over the entire circumference of the power transmission core 18, but is not limited thereto. The first shield member 17 may be configured such that the second member 172 surrounds a part of the power transmission coil 11 and the power transmission core 18, or intermittently surrounds the periphery of the power transmission coil 11 and the power transmission core 18.

[0113] The first magnetic member 173 is provided on the first member 171 and the second member 172. Specifically, the first magnetic member 173 is provided on a portion of the first member 171 that faces the power transmission core 18 in the power transmission direction Z (hereinafter referred to as the bottom portion 176 of the first shield member 17), a portion of the second member 172 that faces the power transmission core 18 in a direction intersecting the power transmission direction Z (hereinafter referred to as the inner portion 174 of the first shield member 17), and a portion of the second member 172 that faces the power receiving device 20 in the power transmission direction Z (hereinafter referred to as the tip portion 175 of the first shield member 17). In the present embodiment, the first magnetic member 173 is provided over the entire bottom portion 176, inner portion 174, and tip portion 175, but is not limited thereto. The first magnetic member 173 may be provided on a part of the bottom portion 176, inner portion 174, and tip portion 175.

[0114] In the present embodiment, the first magnetic member 173 has a thickness smaller than that of the power transmission core 18. For example, the thickness of the first magnetic member 173 provided on the bottom portion 176 and the tip portion 175 is the dimension of each portion of the first magnetic member 173 in the power transmission direction Z. The thickness of the power transmission core 18 is the dimension of the power transmission core 18 in the power transmission direction Z. The thickness of the first magnetic member 173 provided on the inner portion 174 is the dimension of the inner portion 174 in a direction intersecting the power transmission direction Z (for example, the X direction).

[0115] The power receiving device 20 of the system 1 according to the third embodiment includes a power receiving coil 21, a second shield member 27, and a power receiving core 28. The second shield member 27 is configured to be located farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction Z and to have the power receiving coil 21 located therebetween and the power transmission device 10 in the power transmission direction Z. The power receiving core 28 is located between the power receiving coil 21 and the second shield member 27 in the power transmission direction Z.

[0116] The second shield member 27 includes a third member 271, a fourth member 272, and a second magnetic member 273.

[0117] The third member 271 is configured to overlap with the power receiving core 28 when viewed along the power transmission direction Z. In the present embodiment, the third member 271 has a substantially rectangular plate shape and is formed of, for example, a non-magnetic material (e.g., aluminum or copper). The third member 271 is configured such that when viewed along the power transmission direction Z, the power receiving core 28 is located inside the outer contour line of the third member 271.

[0118] The fourth member 272 is located outside the power receiving core 28 in a direction intersecting the power transmission direction Z and extends from the third member 271 in the power transmission direction Z and in a direction approaching the power receiving core 28. In the present embodiment, the fourth member 272 is formed of, for example, a non-magnetic material (e.g., aluminum or copper). The fourth member 272 extends from the third member 271 to the portion of the power transmission device 10 facing the power receiving coil 21, but is not limited thereto. The fourth member 272 may be configured to extend from the third member 271 to a position closer to the power transmission device 10 than the power receiving coil 21, or may be configured to extend from the third member 271 to a position farther from the power transmission device 10 than the power receiving coil 21. The fourth member 272 surrounds the power receiving coil 21 and the power receiving core 28 around the power transmission direction Z over the entire circumference of the power receiving core 28, but is not limited thereto. The second shield member 27 may be configured such that the fourth member 272 surrounds a part of the power receiving coil 21 and the power receiving core 28, or intermittently surrounds the periphery of the power receiving coil 21 and the power receiving core 28.

[0119] The second magnetic member 273 is provided on the third member 271 and the fourth member 272. Specifically, the second magnetic member 273 includes a portion that faces the power receiving core 28 in the power transmission direction Z of the third member 271 (hereinafter referred to as the bottom portion 276 of the second shield member 27), a portion that faces the power receiving core 28 in a direction intersecting the power transmission direction Z of the fourth member 272 (hereinafter referred to as the inner portion 274 of the second shield member 27), and a portion that faces the power transmission device 10 in the power transmission direction Z (hereinafter referred to as the tip portion 275 of the second shield member 27). In the present embodiment, the second magnetic member 273 is provided over the entire bottom portion 276, inner portion 274, and tip portion 275, but is not limited thereto. The first magnetic member 173 may be provided on a part of the bottom portion 276, inner portion 274, and tip portion 275.

[0120] In the present embodiment, the second magnetic member 273 has a thickness smaller than that of the power receiving core 28. For example, the thickness of the second magnetic member 273 provided on the bottom portion 276 and the tip portion 275 is the dimension in the power transmission direction Z of each part of the second magnetic member 273. The thickness of the power receiving core 28 is the dimension in the power transmission direction Z of the power receiving core 28. The thickness of the second magnetic member 273 provided on the inner portion 274 is the dimension in a direction intersecting the power transmission direction Z of the inner portion 274 (for example, the X direction).

[0121] The power transmission device 10 of the third embodiment can exhibit the following effects.

[0122] The power transmission device 10 is a power transmission device capable of wirelessly transmitting power along the power transmission direction Z to the power reception device 20, and includes a power transmission coil 11, a first shield member 17, and a power transmission core 18. The first shield member 17 is positioned farther from the power reception device 20 than the power transmission coil 11 in the power transmission direction Z, and is configured such that the power transmission coil 11 is positioned between the first shield member 17 and the power reception device 20 in the power transmission direction Z. The power transmission core 18 is positioned between the power transmission coil 11 and the first shield member 17 in the power transmission direction Z. The first shield member 17 includes a first member 171, a second member 172, and a first magnetic member 173 provided on the first member 171 and the second member 172. The first member 171 is configured to overlap the power transmission core 18 when viewed along the power transmission direction Z. The second member 172 is positioned outside the power transmission core 18 in a direction intersecting the power transmission direction Z, and extends from the first member 171 in the power transmission direction Z and in a direction approaching the power transmission core 18. The first magnetic member 173 is provided on a portion of the first member 171 facing the power transmission core 18 in the power transmission direction Z, a portion of the second member 172 facing the power transmission core 18 in a direction intersecting the power transmission direction Z, and a portion of the second member 172 facing the power reception device 20 in the power transmission direction Z. With such a configuration, while reducing the leakage magnetic field by the first member 171 and the second member 172, the first magnetic member 173 can induce the magnetic flux toward the inside of the power transmission coil 11 to improve the coupling coefficient. As a result, it is possible to realize the power transmission device 10 capable of reducing the leakage magnetic field while ensuring the WPT (Wireless Power Transmission) efficiency.

[0123] The first magnetic member 173 has a thickness smaller than that of the power transmission core 18. With such a configuration, the manufacturing cost of the power transmission device 10 can be reduced.

[0124] The power reception device 20 of the third embodiment can exhibit the following effects.

[0125] The power receiving device 20 is a power receiving device capable of wirelessly receiving power transmitted from the power transmitting device 10 along the power transmission direction, and includes a power receiving coil 21, a second shielding member 27, and a power receiving core 28. The second shielding member 27 is positioned farther from the power transmitting device 10 than the power receiving coil 21 in the power transmission direction Z, and is configured such that the power receiving coil 21 is positioned between the second shielding member 27 and the power transmitting device 10 in the power transmission direction Z. The power receiving core 28 is positioned between the power receiving coil 21 and the second shielding member 27 in the power transmission direction Z. The second shielding member 27 includes a third member 271, a fourth member 272, and a second magnetic member 273 provided on the third member 271 and the fourth member 272. The third member 271 is configured to overlap the power receiving core 28 when viewed along the power transmission direction Z. The fourth member 272 is positioned outside the power receiving core 28 in a direction intersecting the power transmission direction Z, and extends from the third member 271 in the power transmission direction Z and toward the power receiving core 28. The second magnetic member 273 is provided on a portion of the third member 271 facing the power receiving core 28 in the power transmission direction Z, and portions of the fourth member 272 facing the power receiving core 28 in a direction intersecting the power transmission direction Z and facing the power transmitting device 10 in the power transmission direction Z. With such a configuration, while the leakage magnetic field is reduced by the third member 271 and the fourth member 272, the magnetic flux can be induced toward the inside of the power transmission coil 11 by the second magnetic member 273 to improve the coupling coefficient. As a result, it is possible to realize a power transmitting device 10 capable of reducing the leakage magnetic field while ensuring the WPT efficiency.

[0126] The second magnetic member 273 has a thickness smaller than that of the power receiving core 28. With such a configuration, the manufacturing cost of the power receiving device 20 can be reduced.

[0127] The system 1 of the third embodiment can exhibit the following effects.

[0128] System 1 includes a power transmission device 10 and a power reception device 20 capable of wirelessly receiving power transmitted from the power transmission device 10 along the power transmission direction Z. The power transmission device 10 includes a power transmission coil 11, a first shield member 17, and a power transmission core 18. The first shield member 17 is positioned farther from the power reception device 20 than the power transmission coil 11 in the power transmission direction Z, and is configured such that the power transmission coil 11 is positioned between the first shield member 17 and the power reception device 20 in the power transmission direction Z. The power transmission core 18 is positioned between the power transmission coil 11 and the first shield member 17 in the power transmission direction Z. The first shield member 17 includes a first member 171, a second member 172, and a first magnetic member 173 provided on the first member 171 and the second member 172. The first member 171 is configured to overlap the power transmission core 18 when viewed along the power transmission direction Z. The second member 172 is positioned outside the power transmission core 18 in a direction intersecting the power transmission direction Z, and extends from the first member 171 in the power transmission direction Z and in a direction approaching the power transmission core 18. The first magnetic member 173 is provided on a portion of the first member 171 facing the power transmission core 18 in the power transmission direction Z, a portion of the second member 172 facing the power transmission core 18 in a direction intersecting the power transmission direction Z, and a portion of the second member 172 facing the power reception device 20 in the power transmission direction Z. The power reception device 20 includes a power reception coil 21, a second shield member 27, and a power reception core 28. The second shield member 27 is positioned farther from the power transmission device 10 than the power reception coil 21 in the power transmission direction Z, and is configured such that the power reception coil 21 is positioned between the second shield member 27 and the power transmission device 10 in the power transmission direction Z. The power reception core 28 is positioned between the power reception coil 21 and the second shield member 27 in the power transmission direction Z. The second shield member 27 includes a third member 271, a fourth member 272, and a second magnetic member 273 provided on the third member 271 and the fourth member 272. The third member 271 is configured to overlap the power reception core 28 when viewed along the power transmission direction Z. The fourth member 272 is positioned outside the power reception core 28 in a direction intersecting the power transmission direction Z, and extends from the third member 271 in the power transmission direction Z and in a direction approaching the power reception core 28.The second magnetic member 273 is provided at a portion facing the power receiving core 28 in the power transmission direction Z of the third member 271, a portion facing the power receiving core 28 in a direction intersecting the power transmission direction Z of the fourth member 272, and a portion facing the power transmission device 10 in the power transmission direction Z. With such a configuration, it is possible to realize the system 1 capable of reducing the leakage magnetic field while ensuring the WPT efficiency.

[0129] The system 1, the power transmission device 10, and the power receiving device 20 of the third embodiment can be configured as follows.

[0130] The power transmission device 10 may include a first power transmission auxiliary coil 12 (see FIG. 11) located between the first shield member 17 and the power transmission core 18 in the power transmission direction Z. By configuring in this way, it is possible to realize the power transmission device 10 capable of suppressing the shield loss caused by the eddy current generated when the magnetic field enters the first shield member 17.

[0131] The power transmission device 10 can include a plurality of power transmission auxiliary coils. The plurality of power transmission auxiliary coils are arranged, for example, between the power transmission coil 11 and the first shield member 17 in the power transmission direction Z, and / or outside the power transmission coil 11 in a direction intersecting the power transmission direction Z.

[0132] The power receiving device 20 may include a first power receiving auxiliary coil 22 (see FIG. 11) located between the second shield member 27 and the power receiving core 28 in the power transmission direction Z. By configuring in this way, it is possible to realize the power receiving device 20 capable of suppressing the shield loss caused by the eddy current generated when the magnetic field enters the second shield member 27.

[0133] The power receiving device 20 can include a plurality of power receiving auxiliary coils. The plurality of power receiving auxiliary coils are arranged, for example, between the power receiving coil 21 and the second shield member 27 in the power transmission direction Z, and / or outside the power receiving coil 21 in a direction intersecting the power transmission direction Z.

[0134] The power transmission device 10 can include a control device 14 (see FIG. 1) capable of controlling the current flowing through the power transmission auxiliary coil. Similarly, the power reception device 20 can include a control device 24 (see FIG. 1) capable of controlling the current flowing through the power reception auxiliary coil.

[0135] The first magnetic member 173 is not limited to having a thickness smaller than that of the power transmission core 18, and may have the same thickness as the power transmission core 18 or a thickness larger than that of the power transmission core 18. Similarly, the second magnetic member 273 is not limited to having a thickness smaller than that of the power reception core 28, and may have the same thickness as the power reception core 28 or a thickness larger than that of the power reception core 28.

[0136] The first shielding member 17 and the second shielding member 27 can be applied to the power transmission device 10 and the power reception device 20 of the first embodiment and the second embodiment.

[0137] A third embodiment of the present disclosure will be described below with reference numerals attached.

[0138] The power transmission device 10 according to the first aspect of the third embodiment is a power transmission device capable of wirelessly transmitting power along a power transmission direction to the power reception device 20, including a power transmission coil 11, a first shielding member 17 that is located farther from the power reception device 20 than the power transmission coil 11 in the power transmission direction and has the power transmission coil 11 positioned therebetween and the power reception device 20 in the power transmission direction, and a power transmission core 18 positioned between the power transmission coil 11 and the first shielding member 17 in the power transmission direction, and the first shielding member 17 includes a first member 171 configured to overlap the power transmission core 18 when viewed along the power transmission direction, a second member 172 that is located outside the power transmission core 18 in a direction intersecting the power transmission direction and extends from the first member 171 in the power transmission direction and in a direction approaching the power transmission core 18, the first magnetic member 173 provided on the first member 171 and the second member 172 including the first magnetic member 173 is provided at a portion facing the power transmission core 18 in the power transmission direction of the first member 171, a portion facing the power transmission core 18 in a direction intersecting the power transmission direction of the second member 172, and a portion facing the power receiving device 20 in the power transmission direction.

[0139] The power transmission device 10 according to the second aspect of the third embodiment is the power transmission device 10 according to the first aspect, comprising a first power transmission auxiliary coil 12 located between the first shield member 17 and the power transmission core 18 in the power transmission direction.

[0140] The power transmission device 10 according to the third aspect of the third embodiment is the power transmission device 10 according to the first aspect or the second aspect, the first magnetic member 173 has a thickness smaller than that of the power transmission core 18.

[0141] The power receiving device 20 according to the fourth aspect of the third embodiment is a power receiving device 20 capable of wirelessly receiving power transmitted along the power transmission direction from the power transmission device 10, including a power receiving coil 21, a second shield member 27 located farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction and having the power receiving coil 21 positioned therebetween in the power transmission direction between the power transmission device 10 and the power receiving coil 21, and a power receiving core 28 located between the power receiving coil 21 and the second shield member 27 in the power transmission direction. comprising the second shield member 27 includes a third member 271 configured to overlap the power receiving core 28 when viewed along the power transmission direction, a fourth member 272 located outside the power receiving core 28 in a direction intersecting the power transmission direction and extending from the third member 271 in the power transmission direction and in a direction approaching the power receiving core 28, the second magnetic member 273 provided on the third member 271 and the fourth member 272 including The second magnetic member 273 is provided at a portion facing the power receiving core 28 in the power transmission direction of the third member 271, a portion facing the power receiving core 28 in a direction intersecting the power transmission direction of the fourth member 272, and a portion facing the power transmission device 10 in the power transmission direction.

[0142] The power receiving device 20 according to the fifth aspect of the third embodiment is the power receiving device 20 according to the fourth aspect, and includes a first power receiving auxiliary coil 22 positioned between the second shielding member 27 and the power receiving core 28 in the power transmission direction.

[0143] The power receiving device 20 according to the sixth aspect of the third embodiment is the power receiving device 20 according to the fourth or fifth aspect, wherein the second magnetic member 273 has a thickness smaller than that of the power receiving core 28.

[0144] The system 1 according to the seventh aspect of the third embodiment includes a power transmission device 10, a power receiving device 20 capable of receiving power wirelessly transmitted along the power transmission direction from the power transmission device 10, and the power transmission device 10 includes a power transmission coil 11, a first shielding member 17 that is located farther from the power receiving device 20 than the power transmission coil 11 in the power transmission direction and has the power transmission coil 11 positioned therebetween in the power transmission direction with respect to the power receiving device 20, and a power transmission core 18 positioned between the power transmission coil 11 and the first shielding member 17 in the power transmission direction, and the first shielding member 17 includes a first member 171 configured to overlap the power transmission core 18 when viewed along the power transmission direction, A second member 172 that is located outside the power transmission core 18 in a direction intersecting the power transmission direction and extends from the first member 171 in the power transmission direction and in a direction approaching the power transmission core 18, a first magnetic member 173 provided on the first member 171 and the second member 172, and includes the first magnetic member 173 is provided on a portion of the first member 171 that faces the power transmission core 18 in the power transmission direction, a portion of the second member 172 that faces the power transmission core 18 in a direction intersecting the power transmission direction, and a portion of the second member 172 that faces the power receiving device 20 in the power transmission direction, the power receiving device 20 includes a power receiving coil 21, a second shield member 27 that is located farther from the power transmission device 10 than the power receiving coil 21 in the power transmission direction and has the power receiving coil 21 located therebetween in the power transmission direction with respect to the power transmission device 10, and a power receiving core 28 located between the power receiving coil 21 and the second shield member 27 in the power transmission direction, and is provided with the second shield member 27 includes a third member 271 configured to overlap the power receiving core when viewed along the power transmission direction, a fourth member 272 that is located outside the power receiving core 28 in a direction intersecting the power transmission direction and extends from the third member 271 in the power transmission direction and in a direction approaching the power receiving core 28, and a second magnetic member 273 provided on the third member 271 and the fourth member 272, and includes the second magnetic member 273 is provided on a portion of the third member 271 that faces the power receiving core 28 in the power transmission direction, a portion of the fourth member 272 that faces the power receiving core 28 in a direction intersecting the power transmission direction, and a portion of the fourth member 272 that faces the power transmission device 10 in the power transmission direction.

[0145] By appropriately combining any of the various embodiments or variations thereof, the respective effects can be achieved. Also, combinations of embodiments, combinations of examples, or combinations of an embodiment and an example are possible, and combinations of features from different embodiments or examples are also possible.

[0146] Although the present disclosure has been described in each embodiment with a certain degree of detail, the disclosed content of these embodiments should change in terms of the details of the configuration, and changes in the combination and order of elements in each embodiment can be realized without departing from the scope and spirit of the claimed present disclosure.

Industrial Applicability

[0147] The present disclosure can be applied to, for example, moving bodies such as AGVs (Automated Guided Vehicles) or EVs (Electric Vehicles), pallets used in conveyor lines, and slip rings used in robotic arms and the like.

Explanation of Signs

[0148] 1 System 10 Power Transmission Device 11 Power Transmission Coil 12 First Power Transmission Auxiliary Coil 13 Second Power Transmission Auxiliary Coil 14 Control Device 15 Third Power Transmission Auxiliary Coil 16 Fourth Power Transmission Auxiliary Coil 17 First Shielding Member 18 Power Transmission Core 20 Power Reception Device 21 Power Reception Coil 22 First Power Reception Auxiliary Coil 23 Second Power Reception Auxiliary Coil 24 Control Device 25 Third Power Reception Auxiliary Coil 26 Fourth Power Reception Auxiliary Coil 27 Second Shielding Member 28 Power Reception Core 30, 31, 32, 40, 41, 42 Power supply 33, 34, 43, 44, 61, 62 Switch 35, 36, 45, 46 Variable capacitor 40, 41, 42 Power supply 51, 52 Capacitor 141 Processor 142 Memory device 143 Communication device 171 First member 172 Second member 173 First magnetic member 174 Inner part 175 Tip part 176 Bottom part 181 First main body part 182 First protruding part 241 Processor 242 Memory device 243 Communication device 271 Third member 272 Fourth member 273 Second magnetic member 274 Inner part 275 Tip part 276 Bottom part 281 Second main body part 282 Second protruding part

Claims

1. A power transmission device capable of wirelessly transmitting power transmitted wirelessly along a power transmission direction to a power reception device, a power transmission coil, a first power transmission auxiliary coil located between the power transmission coil and the power reception device in the power transmission direction, and a second power transmission auxiliary coil located outside the power transmission coil in a direction intersecting the power transmission direction The power transmission device comprising.

2. The power transmission device according to claim 1, further comprising a third power transmission auxiliary coil located between the first power transmission auxiliary coil and the power transmission coil in the power transmission direction.

3. The power transmission device according to claim 1 or 2, further comprising a fourth power transmission auxiliary coil located outside the second power transmission auxiliary coil in a direction intersecting the power transmission direction.

4. Comprising a control device capable of controlling a first current flowing through the first power transmission auxiliary coil, The control device is configured to control the first current so that the first current is in phase with the current flowing through the power transmission coil, so as to be able to detect whether a detection target exists in the power transmission direction. The power transmission device according to claim 1.

5. When the control device detects the presence of the detection target, the control device controls the first current so that the first current is out of phase with the current flowing through the power transmission coil, so as to suppress the magnetic field in the power transmission direction. The power transmission device according to claim 4.

6. Comprising a control device capable of controlling a second current flowing through the second power transmission auxiliary coil, The control device is configured to control the second current so that the second current is in phase with the current flowing through the power transmission coil, so as to be able to detect whether a detection target exists in a direction intersecting the power transmission direction. The power transmission device according to claim 1.

7. When the control device detects the presence of the detection target, the control device controls the second current so that the second current is out of phase with the current flowing through the power transmission coil, so as to suppress the magnetic field in a direction intersecting the power transmission direction. The power transmission device according to claim 6.

8. A power reception device capable of receiving power transmitted wirelessly along a power transmission direction from a power transmission device, a power reception coil, a first power reception auxiliary coil located between the power reception coil and the power transmission device in the power transmission direction, and a second power reception auxiliary coil located outside the power reception coil in a direction intersecting the power transmission direction The power reception device comprising.

9. The power receiving device according to claim 8, further comprising a third power receiving auxiliary coil positioned between the power receiving coil in the power transmission direction.

10. The power receiving device according to claim 8 or 9, further comprising a fourth power transmission auxiliary coil positioned outside the second power receiving auxiliary coil in a direction intersecting the power transmission direction.

11. Comprising a control device capable of controlling a third current flowing through the first power receiving auxiliary coil, The control device is configured to control the third current so that the third current is in phase with the current flowing through the power receiving coil, and is configured to be able to detect whether a detection target exists in the power transmission direction. The power receiving device according to claim 8.

12. When the control device detects the presence of the detection target, the control device controls the third current so that the third current is out of phase with the current flowing through the power receiving coil, and is configured to suppress the magnetic field in the power transmission direction. The power receiving device according to claim 11.

13. Comprising a control device capable of controlling a fourth current flowing through the second power receiving auxiliary coil, The control device is configured to control the fourth current so that the fourth current is in phase with the current flowing through the power receiving coil, and is configured to be able to detect whether a detection target exists in a direction intersecting the power transmission direction. The power receiving device according to claim 8.

14. When the control device detects the presence of the detection target, the control device controls the fourth current so that the fourth current is out of phase with the current flowing through the power receiving coil, and is configured to suppress the magnetic field in a direction intersecting the power transmission direction. The power receiving device according to claim 13.

15. A power transmission device, A power receiving device capable of wirelessly receiving power transmitted from the power transmission device along the power transmission direction And comprising, The power transmission device is A power transmission coil, A first power transmission auxiliary coil positioned between the power transmission coil and the power receiving device in the power transmission direction, A second power transmission auxiliary coil positioned outside the power transmission coil in a direction intersecting the power transmission direction Including, The power receiving device is A power receiving coil, A first power receiving auxiliary coil positioned between the power receiving coil and the power transmission device in the power transmission direction, A second power receiving auxiliary coil positioned outside the power receiving coil in a direction intersecting the power transmission direction Including, a system.

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