Wireless power supply system and power transmission device

Abstract

A wireless power supply system (10) comprises: a power transmission device (30) comprising a wireless power transmission circuit including a power transmission coil (34) configured using a first annular conductor; and a power reception device (20) comprising a wireless power reception circuit including a power reception coil (22) configured using a second annular conductor. The power transmission coil (34) and the power reception coil (22) are electromagnetically coupled to perform wireless power supply. The power reception device (20) comprises a power reception device housing (200) which has a complicated outer shape having a plurality of vertices exceeding eight vertices and in which the power reception coil (22) is disposed. The power transmission device (30) comprises a power transmission device housing (H30) in which a recessed housing part (300) having a size capable of accommodating the power reception device housing (200) is formed. The recessed housing part (300) comprises a bottom surface (BT300) and a side surface (F301) installed upright from the bottom surface (BT300). The power reception device housing (200) makes a point contact or a line contact in a plurality of postures at two or more locations on the side surface in a first direction that is the normal to the bottom surface or at one or more locations on each of the bottom surface and the side surface. The first annular conductor has a spiral shape having a first opening, and is disposed in a position where the recessed housing part (300) is disposed in the first opening, and between the bottom surface and the side of the upper end of the power reception device housing (200) in the housed state or the upper end of the recessed housing part (300) that is closer to the bottom surface (BT300). The power reception device housing (200) is housed in the recessed housing part (300) such that a first central axis of the first annular conductor passes through a second opening of the second annular conductor.

Description

Wireless power supply system, power transmission device

[0001] The present invention relates to a wireless power supply technology that is not easily affected by the complex outer shape of a power receiving device.

[0002] Patent Document 1 describes a magnetic field generating device that generates a variable time in a predetermined area. The magnetic field generating device described in Patent Document 1 includes a plurality of power transmission coils. The plurality of power transmission coils are arranged so that their coil surfaces face the predetermined area.

[0003] At least one of the plurality of power transmitting coils is arranged to have a coil plane that intersects with the coil planes of the other power transmitting coils. A current is selectively supplied to the plurality of power transmitting coils and the power transmitting resonator.

[0004] Patent No. 6767119

[0005] The configuration of Patent Document 1 uses a plurality of power transmission coils whose coil surfaces intersect with each other, which results in an increased size of the device.

[0006] Furthermore, if the placement of the power receiving device relative to the power transmitting device is completely fixed, the degree of freedom in placement is lost, which reduces convenience for users.

[0007] Furthermore, small electronic devices such as canal hearing aids have complex shapes that are sometimes customized to fit the user's body. For small electronic devices with such complex shapes, it has not been easy to arrange them on the power transmitting device with a high degree of freedom, regardless of the orientation of the device, and to increase the coupling between the power transmitting coil and the power receiving coil so that the power receiving device can obtain large amounts of power.

[0008] Therefore, an object of the present invention is to provide a wireless power supply technology that suppresses the adverse effects of the complex external shape of the power receiving device, allows the power receiving device to be placed on the power transmitting device with a high degree of freedom in placement, and can increase the electromagnetic field coupling between the power transmitting coil and the power receiving coil.

[0009] The wireless power transfer system of the present invention includes a power transfer device having a wireless power transfer circuit including a power transfer coil configured using a first annular conductor, and a power receiving device having a wireless power receiving circuit including a power receiving coil configured using a second annular conductor, and performs resonant wireless power transfer by forming electromagnetic resonance coupling between the power transfer coil and the power receiving coil. The power receiving device has an outer shape with more than eight vertices and includes a power receiving device housing in which the power receiving coil is disposed. The power transfer device includes a power transfer device housing in which a recessed housing portion large enough to accommodate the power receiving device housing is formed. The recessed housing portion has a bottom surface and side surfaces extending upright from the bottom surface.

[0010] The power receiving device housing is in point or line contact with the power receiving device housing at two or more locations on the side surface in a first direction normal to the bottom surface in a plurality of positions, or at one or more locations on each of the bottom surface and the side surface. The first annular conductor is convoluted and has a first opening, and is positioned at a position where the recessed housing is disposed within the first opening, and is disposed between the top end of the power receiving device housing in the accommodated state, or the top end of the recessed housing closest to the bottom surface, and the bottom surface. The power receiving device housing is accommodated in the recessed housing.

[0011] In this configuration, even if the housing of the power receiving device has a complex external shape, the influence of the accommodation state of the power receiving device in the recessed accommodation portion is suppressed, and the second annular conductor is arranged in a stable position relative to the recessed accommodation portion of the power transmitting device, and the first annular conductor is arranged in a position where the openings of the second annular conductor arranged in the stable position overlap each other.

[0012] This allows the magnetic flux loops formed by the power transmitting coil using the first annular conductor to interlink with the power receiving coil using the second annular conductor over a wide area, thereby increasing the magnitude of electromagnetic coupling between the power transmitting coil and the power receiving coil.

[0013] According to this invention, even if the power receiving device has a complex external shape that is customized to fit the user's body, the adverse effects of the complex external shape of the power receiving device can be suppressed, the power receiving device can be placed on the power transmitting device with a high degree of freedom in placement, and the magnitude of the electromagnetic field resonance coupling formed by the power transmitting coil and the power receiving coil can be increased, making it possible to wirelessly supply large amounts of power with greater power efficiency than wireless power supply that uses only electromagnetic induction technology.

[0014] FIG. 1 is a functional block diagram of a wireless power supply system according to an embodiment of the present invention. FIG. 2(A) is a perspective view of a power receiving device according to an embodiment of the present invention, FIG. 2(B) is a first side view of the power receiving device, and FIG. 2(C) is a second side view of the power receiving device. FIG. 3(A) is a perspective view showing a portion of a power transmitting device according to an embodiment of the present invention, and FIG. 3(B) is a side cross-sectional view of the power transmitting device. FIG. 4(A) is a perspective view showing a state in which a power receiving device according to an embodiment of the present invention is arranged on a power transmitting device, and FIG. 4(B) is a side cross-sectional view of this state. FIG. 5 is a diagram showing an example of a method of arranging a power receiving device on a power transmitting device according to an embodiment of the present invention. FIG. 6 is a perspective view of a power transmitting device capable of wirelessly supplying power to multiple power receiving devices simultaneously.

[0015] A wireless power supply system according to an embodiment of the present invention will be described with reference to the drawings.

[0016] 1 is a functional block diagram of a wireless power supply system according to an embodiment of the present invention. As shown in FIG. 1, the wireless power supply system 10 includes a power receiving device 20 and a power transmitting device 30.

[0017] The power receiving device 20 includes a power receiving circuit 21, a charge control circuit 25, a secondary battery 26, and a load circuit 27. The power receiving circuit 21 includes a power receiving coil 22, a power receiving resonant capacitor 23, and a rectifying and smoothing circuit 24. The power receiving coil 22 and the power receiving resonant capacitor 23 are connected in series. The series circuit of the power receiving coil 22 and the power receiving resonant capacitor 23 forms a power receiving resonant circuit.

[0018] The power receiving resonant circuit is electrically connected to an input terminal of a rectifying and smoothing circuit 24. An output terminal of the rectifying and smoothing circuit 24 is electrically connected to an input terminal of a charging control circuit 25. An output terminal of the charging control circuit 25 is electrically connected to a secondary battery 26. The secondary battery 26 is electrically connected to a load circuit 27.

[0019] The power transmitting device 30 includes a power transmitting control circuit 31, a switching circuit 32, a power transmitting resonance capacitor 33, and a power transmitting coil 34. The power transmitting control circuit 31 is electrically connected to a direct current power source DC and to a control signal input terminal of the switching circuit 32.

[0020] A power input terminal of the switching circuit 32 is electrically connected to a direct-current power source DC. A control signal input terminal of the switching circuit 32 is electrically connected to the power transmission control circuit 31. An output terminal of the switching circuit 32 is connected to a series circuit of a power transmission resonance capacitor 33 and a power transmission coil 34. The series circuit of the power transmission resonance capacitor 33 and the power transmission coil 34 forms a power transmission resonance circuit.

[0021] The above-described circuit configuration of the power receiving device 20 and the power transmitting device 30 is an example, and the power receiving coil 22 and the power receiving resonant capacitor 23 of the power receiving device 20 may be connected in parallel. Furthermore, the power receiving device 20 and the power transmitting device 30 only need to have at least the above-described configuration, and may also have other circuit configurations.

[0022] (General Description of Power Supply Using Wireless Power Supply System 10) The power transmission control circuit 31 is realized by an MPU or the like. The power transmission control circuit 31 is driven by receiving DC power from a DC power source DC. The power transmission control circuit 31 generates a control signal to perform switching control at a predetermined switching frequency in the switching circuit 32, and outputs the control signal to the switching circuit 32.

[0023] The switching circuit 32 is configured using power semiconductor switching elements, etc. The switching circuit 32 receives a control signal and performs on / off control (switching control) of the power semiconductor switching elements. As a result, the DC voltage supplied to the switching circuit 32 from the DC power source DC is converted into an AC voltage of a switching frequency, and the AC current is supplied to a power transmitting resonant circuit made up of a power transmitting resonant capacitor 33 and a power transmitting coil 34.

[0024] The resonant frequency of the power transmitting resonant circuit is set to be substantially the same as the switching frequency. The power transmitting coil 34 excites an alternating magnetic field by an alternating current. This alternating magnetic field generates an external magnetic field by the power transmitting coil 34.

[0025] When the power receiving device 20 is disposed on the power transmitting device 30 so that the power receiving coil 22 is linked to the external magnetic field generated by the power transmitting coil 34 , a receiving current flows through the power receiving coil 22 .

[0026] The resonant frequency of the power receiving resonant circuit formed by the power receiving coil 22 and the power receiving resonant capacitor 23 is set to be substantially the same as the resonant frequency and switching frequency of the power transmitting resonant circuit. As a result, the power receiving coil 22 and the power transmitting coil 34 form an electromagnetic resonant field, achieving DC resonant electromagnetic coupling (electromagnetic resonant coupling). By achieving DC resonant electromagnetic coupling in this manner, power can be supplied from the power transmitting coil 34 to the power receiving coil 22 with low loss (high efficiency), thereby achieving low-loss wireless power transfer. Therefore, compared to wireless power transfer using only electromagnetic induction technology, large power can be transferred wirelessly (resonant wireless power transfer) with high power efficiency. In the description of this embodiment, unless otherwise specified, electromagnetic field coupling refers to electromagnetic resonant coupling.

[0027] This resonant frequency is preferably in the 6.78 MHz band or the 13.56 MHz band of the ISM band, which allows for safe wireless power transfer.

[0028] The rectifying and smoothing circuit 24 is realized by various rectifying circuits using switching elements and a smoothing capacitor. The rectifying and smoothing circuit 24 converts the AC receiving current input from the power receiving resonant circuit into DC power, smoothes it, and outputs a DC voltage (DC current) to the charge control circuit 25.

[0029] The charge control circuit 25 is realized by a voltage conversion circuit such as a DC-DC converter. The charge control circuit 25 converts the input DC voltage into an output DC voltage for charging the secondary battery 26 and outputs it to the secondary battery 26. The secondary battery 26 is charged by the input voltage (input current) from the charge control circuit 25.

[0030] Also, for example, when the power receiving device 20 is not receiving power supply from the power transmitting device 30 (e.g., when the power receiving device 20 is being used alone), the secondary battery 26 outputs load driving power (load driving voltage, load driving current) from the stored power to the load circuit 27.

[0031] The load circuit 27 receives a supply of load driving power from the secondary battery 26 and performs desired signal processing, etc. For example, if the load circuit 27 is a circuit that performs a hearing aid function, the load circuit 27 includes a microphone, a signal processing circuit such as a filter, an amplifier circuit, and a speaker. The load circuit 27 receives a supply of load driving power, filters and amplifies the sound signal picked up by the microphone, and emits the sound from the speaker.

[0032] In such a wireless power transfer system 10, the state of electromagnetic field coupling between the power transmitting coil 34 and the power receiving coil 22 when wirelessly transferring power from the power transmitting device 30 to the power receiving device 20 has a significant effect on power transfer efficiency. Specifically, the greater the magnitude of the electromagnetic field coupling between the power transmitting coil 34 and the power receiving coil 22, the higher the power transfer efficiency. For this reason, the positional relationship between the power transmitting coil 34 and the power receiving coil 22 when wirelessly transferring power becomes important.

[0033] However, if the external shape of the power receiving device 20 becomes complex, it becomes difficult to stabilize the position of the power receiving coil 22 built into the power receiving device 20 and arrange it on the power transmitting device 30. Therefore, the wireless power feed system 10 and the power transmitting device 30 of this embodiment solve this problem by having the following configuration. Below, the configuration of the power receiving device 20, the configuration of the power transmitting device 30, and the arrangement of the power receiving device 20 on the power transmitting device 30 will be described in that order.

[0034] (Configuration of power receiving device 20) Fig. 2(A) is a perspective view of a power receiving device according to an embodiment of the present invention, Fig. 2(B) is a first side view of the power receiving device, and Fig. 2(C) is a second side view of the power receiving device. Note that, in the following, to facilitate the explanation of the structure of the power receiving device 20, three orthogonal axes, i.e., x20 axis, y20 axis, and z20 axis, are set for the power receiving device 20, but this does not limit the manner in which the power receiving device 20 is arranged or used.

[0035] 2A, 2B, and 2C, the power receiving device 20 includes a power receiving device housing 200, a power receiving coil 22, and a circuit module (not shown) of the power receiving device 20. The power receiving device housing 200 includes a first housing unit 201 and a second housing unit 202.

[0036] The first housing unit 201 and the second housing unit 202 are aligned in the extension direction (longitudinal direction: z20 axis direction) of the power receiving device housing 200 and are physically connected to each other. In the alignment direction of the first housing unit 201 and the second housing unit 202, the end of the power receiving device housing 200 on the first housing unit 201 side is a first end E1 of the power receiving device housing 200, and the end of the power receiving device housing 200 on the second housing unit 202 side is a second end E2 of the power receiving device housing 200.

[0037] Both the first housing 201 and the second housing 202 have an internal space. The internal space of the first housing 201 and the internal space of the second housing 202 are in communication with each other.

[0038] The first housing 201 has a generally cubic shape with rounded corners. The second housing 202 has a generally cylindrical shape with rounded corners. The shape of the first housing 201 may be a generally rectangular parallelepiped shape, a generally spherical shape, or the like.

[0039] One end of the cylindrical extension direction of the second housing unit 202 is connected to the first housing unit 201. In this case, the extension direction of the second housing unit 202 does not have to be parallel to the direction in which the first housing unit 201 and the second housing unit 202 are aligned. For example, if the power receiving device 20 is a hearing aid or the like, the extension direction of the second housing unit 202 may have a predetermined angle (not 0°) with respect to the direction in which the first housing unit 201 and the second housing unit 202 are aligned, based on the shape of the wearer's ear canal, etc. Furthermore, the second housing unit 202 may be curved or bent at a position midway in the extension direction.

[0040] The first housing 201 has a housing orthogonal cross-sectional area S201 of the first housing 201 as the maximum cross-sectional area in the cross-sectional area perpendicular to the direction in which the first housing 201 and the second housing 202 are arranged.

[0041] The second housing unit 202 has a housing orthogonal cross-sectional area S202 of the second housing unit 202 as the maximum cross-sectional area in the cross-sectional area perpendicular to the direction in which the first housing unit 201 and the second housing unit 202 are arranged.

[0042] The orthogonal cross-sectional area S201 of the first housing part 201 is larger than the orthogonal cross-sectional area S202 of the second housing part 202.

[0043] 2(A), 2(B), and 2(C), the power receiving device housing 200 has at least a plurality of corners CN11, CN12, CN13, CN14, CN21, CN22, CN23, CN24, CN31, CN32, CN41, CN42, CN43, and CN44. Note that, in the power receiving device housing 200, these corners are chamfered and rounded, but the shape of the corners is not limited to this.

[0044] With this configuration, the power receiving device housing 200 has a complex outer shape with more than eight vertices.

[0045] The receiving coil 22 is configured using a spiral annular conductor (second annular conductor) having an opening (second opening). The second annular conductor is disposed inside the first housing 201. The second annular conductor is disposed at a predetermined position between the first end E1 of the first housing 201 and the connection end to the second housing 202.

[0046] The axial direction of the second annular conductor (axial direction of the spiral shape: direction perpendicular to the second opening surface) is approximately parallel to the direction in which the first housing part 201 and the second housing part 202 are aligned (z20 axis direction).

[0047] The circuit module of the power receiving device 20 includes the power receiving resonant capacitor 23, the charge control circuit 25, the secondary battery 26, and the load circuit 27 shown in FIG. 1 . For example, when the power receiving device 20 is a hearing aid, the circuit module of the power receiving device 20 is divided into at least two parts. The first part including the power receiving resonant capacitor 23, the charge control circuit 25, and the secondary battery 26 is disposed inside the first housing 201. More specifically, the first part is disposed inside the first housing 201 and more inward than the second annular conductor when viewed in a direction perpendicular to the first end E1. The second part including the load circuit 27 is disposed inside the second housing 202.

[0048] (Configuration of Power Transmission Device 30) FIG. 3A is a perspective view showing a part of the power transmission device according to the embodiment of the present invention, and FIG. 3B is a side cross-sectional view of the power transmission device.

[0049] As shown in FIGS. 3A and 3B, the power transmission device 30 includes a power transmission device housing H30, a power transmission coil 34, and a circuit module of the power transmission device 30 (not shown).

[0050] The power transmission device housing H30 has a top surface F30 and a recess 300. The recess 300 corresponds to the recessed housing portion.

[0051] The recess 300 has a shape recessed from the top surface F30 of the power transmission device housing H30. The recess 300 includes a first housing portion 301 and a second housing portion 302. The first housing portion 301 and the second housing portion 302 are in communication with each other.

[0052] The first accommodating portion 301 is cylindrical and has a constant diameter φ301. The axial direction of the cylinder (the direction of the dotted line in FIG. 3B ) is perpendicular to the top surface F30 of the power transmission device housing H30. One end of the cylinder in the axial direction opens from the top surface F30 to the outside. This opening serves as an opening OP300 of the recess 300.

[0053] The first accommodating portion 301 has a side surface F301. The side surface F301 is substantially parallel to the depth direction of the recess 300.

[0054] The second storage section 302 is generally conical in shape, with a circular tip of a predetermined area. The second storage section 302 is connected to the first storage section 301 at the bottom of the generally conical shape. The diameter of the second storage section 302 at this point is equal to the diameter of the first storage section 301.

[0055] The second accommodating portion 302 has a diameter that decreases with increasing distance from the first accommodating portion 301 in the height direction of the substantially conical shape, in other words, in the depth direction of the recess 300 .

[0056] The second housing portion 302 has a side surface F302. The side surface F302 is angled with respect to the depth direction of the recess 300, and the distance to the central axis decreases as the side surface F302 becomes farther from the first housing portion 301. The second housing portion 302 also has a bottom surface BT300. The bottom surface BT300 is circular when viewed in a direction parallel to the central axis, and has a diameter φ309.

[0057] As a result, the recess 300 opens with a diameter φ301 on the top surface F30, and also has a diameter φ301 in the first storage section 301, and the diameter gradually decreases from diameter φ301 in the second storage section 302, to a diameter φ309 (<φ301) at the bottom surface BT300.

[0058] The power transmission coil 34 is configured using a spiral annular conductor (first annular conductor) having an opening (first opening). The first annular conductor is disposed inside the power transmission device housing H30. More specifically, the first annular conductor is disposed at a position where the first housing portion 301 is disposed inside the first opening, between the upper end of the first housing portion 301 (the position of the opening OP300) and the connection portion to the second housing portion 302 (the deepest portion of the first housing portion 301).

[0059] The axial direction of the first annular conductor (the axial direction of the convoluted shape) is approximately parallel to the axial direction of the first accommodating portion 301 , in other words, the depth direction of the recess 300 .

[0060] The circuit module of the power transmitting device 30 includes at least the power transmitting control circuit 31, the switching circuit 32, and the power transmitting resonant capacitor 33 shown in Fig. 1. The circuit module of the power transmitting device 30 is disposed in a position that does not block the magnetic field generated by the power transmitting coil 34 (first annular conductor).

[0061] (Arrangement of power receiving device 20 on power transmitting device 30) FIG. 4A is a perspective view showing a state in which a power receiving device according to an embodiment of the present invention is arranged on a power transmitting device, and FIG. 4B is a side cross-sectional view of this state.

[0062] The diameter φ301 of the first accommodating portion 301 in the recess 300 of the power transmitting device 30 is larger than the diameter of the surface of the housing orthogonal cross-sectional area S201 (referred to as the maximum diameter of the first housing portion 201) of the first housing portion 201 of the power receiving device 20. Note that the diameter φ301 is not significantly larger than the maximum diameter of the first housing portion 201, but is approximately the same as but larger.

[0063] The diameter φ309 of the bottom surface of the second accommodating section 302 is at least twice the distance between the tip of the second end E2 of the second casing section 202 of the power receiving device casing 200 and the central axis Ax20 of the power receiving device casing 200 when the power receiving device casing 200 is accommodated in the recess 300.

[0064] The central axis Ax20 of the power receiving device housing 200 is, as shown mainly in Figure 2 (B), approximately parallel to the direction in which the first housing part 201 and the second housing part 202 in the power receiving device housing 200 are aligned, and is a straight line located at a position where the maximum distance L2011 and the maximum distance L2012 of the surfaces facing each other across the central axis Ax20 in the first housing part 201 coincide.

[0065] In this configuration, the power receiving device housing 200 is accommodated in the recess 300 so that the second housing part 202 is inserted at a deeper position than the first housing part 201. More specifically, the power receiving device housing 200 has the first housing part 201 disposed in the first housing part 301 and at least a portion of the second housing part 202 disposed in the second housing part 302.

[0066] In this case, the central axis of the recess 300 and the central axis Ax20 of the power receiving device housing 200 are approximately parallel to each other and are arranged at approximately the same position. Since the shape of the first housing 301 and the shape of the first housing unit 201 have the above-mentioned relationship, and the shape of the second housing 302 and the shape of the second housing unit 202 have the above-mentioned relationship, the housing unit orthogonal cross-sectional area of ​​the first housing unit 301 is larger than the housing orthogonal cross-sectional area of ​​the first housing unit 201 at any position in the direction in which each central axis extends. Furthermore, the housing unit orthogonal cross-sectional area of ​​the second housing unit 302 is larger than the housing orthogonal cross-sectional area of ​​the second housing unit 202 at any position in the direction in which each central axis extends.

[0067] In this state, when the power receiving device housing 200 is accommodated in the recess 300, as shown in Figures 4(A) and 4(B), the power receiving device housing 200 makes point or line contact with the recess 300 at two or more locations on the side F301 and the side F302 in a first direction that is normal to the bottom surface BT300 of the second accommodating section 302 of the recess 300 in multiple postures.

[0068] 4A and 4B, the power receiving device housing 200 contacts the side surface F301 of the first housing portion 301 at a first position PCH, which is located on one end of the first housing portion 201 and furthest from the side in a direction perpendicular to the central axis, and at a second position PCL, which is located on the other end of the first housing portion 201 and furthest from the side in a direction perpendicular to the central axis. The first position PCH and the second position PCL are located at different positions in a direction parallel to the central axis (the depth direction of the recess 300: the first direction). In the first direction, the first position PCH is closer to the opening OP300 at the top of the recess 300 than the second position PCL.

[0069] When the power receiving device housing 200 is accommodated in the recess 300 in this manner, the power receiving device housing 200 rotates around the central axis as the center of rotation, and even if it assumes multiple positions, it always contacts the side of the recess 300 at multiple positions between the upper end (opening OP300) of the recess 300 in the first direction and the bottom surface BT300, thereby stabilizing the position.

[0070] The power receiving device housing 200 may be in point contact or line contact with the bottom surface BT300 and one or more locations on each of the side surfaces F301 and F302 of the recess 300 in a plurality of positions. For example, as shown in FIG. 4B , the power receiving device housing 200 is accommodated in the recess 300 so that the second end E2 of the second housing part 202 contacts the bottom surface BT300 of the recess 300 (contact at the bottom surface position PCB) and contacts the bottom surface BT300 at at least one location corresponding to the first position PCH and the second position PCL. Even in this case, even when the power receiving device housing 200 rotates about the central axis and assumes a plurality of positions, contact is always made at multiple locations between the upper end (opening OP300) of the recess 300 in the first direction and the bottom surface BT300, and on the bottom surface BT300, thereby stabilizing the position.

[0071] In this arrangement, the arrangement of the power transmission coil 34 (first annular conductor) relative to the recess 300 and the arrangement of the power receiving coil 22 (second annular conductor) relative to the power receiving device housing 200 are as described above, so that the power receiving coil 22 (second annular conductor) is positioned within the opening of the power transmission coil 34.

[0072] That is, the power receiving device housing 200 is accommodated in the recess 300 so that the central axis (first central axis) of the power transmitting coil 34 (first annular conductor) passes through the opening (second opening) of the power receiving coil 22 (second annular conductor).

[0073] This allows the magnetic flux loop created by the power transmitting coil 34 (first annular conductor) to more reliably interlink with the power receiving coil 22 (second annular conductor). Therefore, the wireless power transfer system 10 can increase the magnitude of the electromagnetic field coupling between the power transmitting coil 34 and the power receiving coil 22 regardless of the orientation of the power receiving device 20 relative to the power transmitting device 30.

[0074] As a result, the wireless power supply system 10 can supply power from the power transmitting device 30 to the power receiving device 20 with low loss and high efficiency, even if the power receiving device 20 has a complex external shape. In other words, the wireless power supply system 10 suppresses the adverse effects of the complex external shape of the power receiving device 20, allows the power receiving device 20 to be arranged on the power transmitting device 30 with a high degree of freedom in arrangement, and can increase the electromagnetic field coupling between the power transmitting coil 34 and the power receiving coil 22, allowing for large power to be supplied.

[0075] 4B , the power transmitting coil 34 (first annular conductor) is disposed between the bottom surface BT300 and the upper end contact portion (first position PCH in the figure) that is the farthest from the bottom surface BT300 among the two or more contact portions. The power receiving coil 22 (second annular conductor) is disposed between the position closest to the second end E2 of the power receiving device housing 200 (the position closest to the bottom surface BT300) and the upper end contact portion (first position PCH in the figure) (including the upper end contact portion).

[0076] As a result, the power transmitting coil 34 (first annular conductor) and the power receiving coil 22 (second annular conductor) are positioned close to each other in the depth direction of the recess 300. Therefore, the magnetic flux loop created by the power transmitting coil 34 (first annular conductor) interlinks with the power receiving coil 22 (second annular conductor) to an even greater extent.

[0077] Furthermore, the power transmitting coil 34 (first annular conductor) is disposed at a position closer to the first position PCH than the bottom surface BT300 in the depth direction (first direction) of the recess 300. The power receiving coil 22 (second annular conductor) is disposed at a position closer to the upper end (first end E1) than to the lower end (second end E2) when the power receiving device housing 200 is accommodated in the recess 300.

[0078] As a result, the power transmitting coil 34 (first annular conductor) and the power receiving coil 22 (second annular conductor) are positioned close to each other in the depth direction of the recess 300. Therefore, the magnetic flux loop created by the power transmitting coil 34 (first annular conductor) interlinks with the power receiving coil 22 (second annular conductor) to an even greater extent.

[0079] Furthermore, in the configuration of this embodiment, the power transmitting coil 34 (first annular conductor) and the power receiving coil 22 (second annular conductor) overlap in the depth direction (first direction) of the recess 300 .

[0080] As a result, the magnetic flux loop created by the power transmission coil 34 (first annular conductor) is further largely linked to the power receiving coil 22 (second annular conductor).

[0081] Furthermore, in the configuration of this embodiment, the receiving device housing 200 is accommodated in the recess 300 so that the central axis (first central axis) of the transmitting coil 34 (first annular conductor) and the central axis (second central axis) of the receiving coil 22 (second annular conductor) are parallel to each other.

[0082] As a result, the magnetic flux loop created by the power transmission coil 34 (first annular conductor) is further largely linked to the power receiving coil 22 (second annular conductor).

[0083] In the above description, when the power receiving device housing 200 is housed in the recess 300, the first end E1 of the power receiving device housing 200 protrudes outward beyond the upper end (opening OP300) of the recess 300.

[0084] However, the recess 300 may have a shape that accommodates the entire power receiving device housing 200. In other words, the recess 300 may have a shape that, when the power receiving device housing 200 is accommodated in the recess 300, the first end E1 of the power receiving device housing 200 is located closer to the bottom surface BT300 than the upper end (opening OP300) of the recess 300.

[0085] In this case, the power transmitting coil 34 (first annular conductor) is preferably located between the first end E1 and the bottom surface BT300 when the power receiving device housing 200 is housed in the recess 300. This ensures that the power transmitting coil 34 (first annular conductor) and the power receiving coil 22 (second annular conductor) are positioned closer to each other in the depth direction of the recess 300.

[0086] 5 is a diagram showing an example of a method for arranging a power receiving device 20 on a power transmitting device 30 according to an embodiment of the present invention. In this description, the power receiving device 20 is a device worn on an ear, such as a hearing aid.

[0087] When using the power receiving device 20, the user wears the power receiving device 20 on the ear. At this time, the user wears the power receiving device 20 so that the second housing unit 202 is housed in the ear canal. In this case, the first housing unit 201 is exposed to the outside from the ear.

[0088] When placing the power receiving device 20 on the power transmitting device 30 from this state in order to charge the secondary battery 26 of the power receiving device 20, the user typically pinches the first housing part 201 that is exposed to the outside from the ear and removes the power receiving device 20 from the ear.

[0089] While holding the first housing part 201, the user places the power receiving device 20 in the recess 300 of the power transmitting device 30. As a result, the power receiving device housing 200 of the power receiving device 20 is placed in the recess 300 of the power transmitting device 30 and fixed as described above.

[0090] As described above, in the configuration of this embodiment, the user does not need to change the grip of the power receiving device 20 to accommodate it in the power transmitting device 30. That is, the user can easily accommodate the power receiving device 20 in the power transmitting device 30 through a natural detachment action. Even with this action, the power receiving device 20 is accommodated in the power transmitting device 30 in a state that allows for increased electromagnetic field coupling between the power transmitting coil 34 and the power receiving coil 22. Therefore, the wireless power transfer system 10 can supply large power from the power transmitting device 30 to the power receiving device 20.

[0091] (Power Transmitter Device Having Multiple Recesses) The above-described single power transmitter device 30 is configured to wirelessly feed power to one power receiver device 20. However, a configuration in which one power transmitter device wirelessly feeds power to multiple power receiver devices can also be realized.

[0092] Fig. 6 is a perspective view of a power transmitting device capable of wirelessly feeding power to a plurality of power receiving devices simultaneously. As shown in Fig. 6, the power transmitting device 30A includes a power transmitting device housing H30A, a recess 3001, a recess 3002, a power transmitting coil 341, and a power transmitting coil 342. Although not shown, a circuit module on the power transmitting device side that supplies AC voltage (AC current) for feeding power to the power transmitting coils 341 and 342 is housed inside the power transmitting device housing H30A.

[0093] The recesses 3001 and 3002 are recessed from the top surface F30 of the power transmission device housing H30A. The shapes of the recesses 3001 and 3002 are the same as the recess 300 described above. The recesses 3001 and 3002 are spaced apart from each other.

[0094] The recess 3001 has an opening OP3001 in the upper surface F30. The recess 3002 has an opening OP3002 in the upper surface F30.

[0095] The power transmitting coil 341 and the power transmitting coil 342 are configured using a spiral annular conductor having an opening. The annular conductors that make up the power transmitting coil 341 and the power transmitting coil 342 have the same configuration as the first annular conductor that makes up the power transmitting coil 34. The arrangement of the annular conductor that makes up the power transmitting coil 341 in the recess 3001 and the arrangement of the annular conductor that makes up the power transmitting coil 342 in the recess 3002 are the same as the arrangement of the first annular conductor that makes up the power transmitting coil 34 in the recess 300.

[0096] A plurality of power receiving devices (not shown) are respectively accommodated in the recesses 3001 and 3002. The accommodation of the plurality of power receiving devices in the recesses 3001 and 3002 is similar to the accommodation of the power receiving device 20 in the recess 300 described above.

[0097] With this configuration, the power transmission device 30A can wirelessly feed power to multiple power receiving devices simultaneously. The power transmission device 30A can increase the electromagnetic field coupling between the power receiving coil of the power receiving device housed in the recess 3001 and the power transmission coil 341, and can also increase the electromagnetic field coupling between the power receiving coil of the power receiving device housed in the recess 3002 and the power transmission coil 342. This allows the power transmission device 30A to feed power to multiple power receiving devices with low loss and high efficiency.

[0098] 6, the recess 3001 and the recess 3002 have the same shape. However, the recess 3001 and the recess 3002 may have different shapes according to the shapes of the power receiving device housings of the power receiving devices to be accommodated therein, in accordance with the shape of the recess 300 described above.

[0099] Furthermore, although the power transmitting device 30A has two recesses, it may have three or more recesses.

[0100] <1> A resonant wireless power transfer system comprising: a power transmitting device having a wireless power transmitting circuit including a power transmitting coil configured using a first annular conductor; and a power receiving device having a wireless power receiving circuit including a power receiving coil configured using a second annular conductor, wherein the power transmitting coil and the power receiving coil form electromagnetic resonance coupling to wirelessly transfer power, wherein the power receiving device has an outer shape with more than eight vertices and comprises a power receiving device housing in which the power receiving coil is arranged, the power transmitting device comprises a power transmitting device housing in which a recessed housing portion having a size large enough to accommodate the power receiving device housing is formed, the recessed housing portion having a bottom surface and a side surface extending from the bottom surface, and the power receiving device housing is in point contact or line contact with the power receiving device housing at two or more locations on the side surface in a first direction that is normal to the bottom surface, or at one or more locations on each of the bottom surface and the side surface, in a plurality of orientations, the first annular conductor is a spiral having a first opening, and is arranged at a position where the recessed accommodating portion is disposed within the first opening, and between the top end of the power receiving device housing in an accommodated state or the top end of the recessed accommodating portion closest to the bottom surface and the bottom surface; the power receiving device housing is accommodated in the recessed accommodating portion; and the magnetic flux loop created by the power transmitting coil is linked to the power receiving coil, thereby increasing the magnitude of the electromagnetic field resonance coupling.

[0101] <2> The wireless power supply system of <1>, wherein the second annular conductor is a spiral having a second opening and is arranged within the power receiving device housing, and the power receiving device housing is accommodated in the recessed accommodating portion so that a first central axis of the first annular conductor passes through the second opening of the second annular conductor.

[0102] <3> The wireless power feeding system of <1> or <2>, wherein the power transmitting device includes a power transmitting resonant capacitor that forms a resonant circuit together with the power transmitting coil, and the power receiving device includes a power receiving resonant capacitor that forms a resonant circuit together with the power receiving coil, and the power transmitting coil and the power transmitting resonant capacitor, and the power receiving coil and the power receiving resonant capacitor form the electromagnetic field resonance coupling to feed power wirelessly.

[0103] <4> The wireless power supply system of <1> or <2>, wherein the power transmitting coil is disposed between the bottom surface and an upper-end contact portion, which is farthest from the bottom surface among the two or more contact portions, and the power receiving coil is disposed between a position on the power receiving device housing closest to the bottom surface and the upper-end contact portion.

[0104] <5> The wireless power supply system of <4>, wherein the power transmitting coil is disposed at a position closer to the upper end contact portion than the bottom surface in the first direction, and the power receiving coil is disposed at a position closer to the upper end than the lower end when the power receiving device housing is housed in the recessed housing.

[0105] <6> The wireless power supply system according to any one of <1> to <5>, wherein the power receiving device housing is accommodated in the recessed accommodating portion so that a first central axis of the first annular conductor and a second central axis of the second annular conductor are parallel to each other.

[0106] <7> The recessed accommodating portion comprises: a cylindrical first accommodating portion that includes the upper end and has a constant orthogonal cross-sectional area regardless of its position in the first direction; and a cone-shaped second accommodating portion that communicates with the first accommodating portion, has the bottom surface, and has an accommodating portion orthogonal cross-sectional area orthogonal to the first direction that increases as the accommodating portion approaches the upper end from the bottom surface in the first direction; The power receiving device casing comprises: a first casing portion that has a larger casing orthogonal cross-sectional area orthogonal to the extension direction of the power receiving device casing; and a second casing portion that has a smaller casing orthogonal cross-sectional area; The power receiving device casing is accommodated in the recessed accommodating portion such that at least a portion of the first casing portion is inside the first accommodating portion; and in a state where the power receiving device casing is accommodated in the recessed accommodating portion, at any position in the first direction, the accommodating portion orthogonal cross-sectional area of ​​the first accommodating portion is larger than the casing orthogonal cross-sectional area of ​​the first casing portion, The wireless power supply system according to any one of <1> to <6>, wherein a housing orthogonal cross-sectional area of ​​the second housing portion is larger than a housing orthogonal cross-sectional area of ​​the second housing portion.

[0107] <8> The wireless power supply system of <7>, wherein the power transmitting coil is disposed at a position corresponding to the first housing portion in the first direction, and the power receiving coil is disposed inside the first housing portion in the first direction.

[0108] <9> The wireless power supply system according to any one of <1> to <8>, wherein a position of the first annular conductor and a position of the second annular conductor in the first direction overlap with each other.

[0109] <10> A power transmission device of a wireless power supply system, comprising: a wireless power transmission circuit including a power transmission coil constructed using a first annular conductor; and the power transmission device performs wireless power supply by coupling an electromagnetic field excited by the power transmission coil to a power receiving coil housed in a power receiving device housing having an external shape with more than eight vertices; the power transmission device housing has a recessed housing portion formed therein large enough to house the power receiving device housing; the recessed housing portion has a bottom surface and a side surface erected from the bottom surface, and is shaped to make point or line contact with the power receiving device housing at two or more locations on the side surface in a first direction that is normal to the bottom surface in a plurality of postures, or at one or more locations on each of the bottom surface and the side surface; and the first annular conductor is convoluted with a first opening, and is arranged at a position where the recessed housing portion is arranged within the first opening, and between an upper end of the recessed housing portion and the bottom surface.

[0110] <11> The power transmitting device according to <10>, wherein the power transmitting coil is disposed at a position closer to the top end than to the bottom surface in the first direction.

[0111] <12> The power transmission device described in <11>, wherein the recessed accommodating portion includes: a first accommodating portion having the bottom surface and a cone-shaped cross-sectional area perpendicular to the first direction that increases as the recessed accommodating portion approaches the top end from the bottom surface in the first direction; and a second accommodating portion having a cylindrical shape that communicates with the first accommodating portion, includes the top end, and has a constant cross-sectional area perpendicular to the first direction regardless of the position in the first direction.

[0112] <13> The power transmitting device according to <12>, wherein the power transmitting coil is disposed at a position corresponding to the second housing portion in the first direction.

[0113] <14> The power transmitting device according to <12> or <13>, wherein the first housing portion has a truncated cone shape, and the second housing portion has a cylindrical shape.

[0114] <15> The wireless power supply system according to any one of <1> to <9>, wherein the frequency of the magnetic field that generates the electromagnetic resonance coupling is in the 6.78 MHz band or the 13.56 MHz band of the ISM band.

[0115] <16> The wireless power supply system according to any one of <1> to <9> and <15>, wherein the power receiving device includes a secondary battery in a housing of the power receiving device, the secondary battery being electrically connected to the wireless power receiving circuit.

[0116] <17> The wireless power supply system according to <16>, wherein the secondary battery is a thin battery.

[0117] <18> The wireless power supply system according to <16> or <17>, wherein the power receiving device includes a power receiving circuit electrically connected to the wireless power receiving circuit and the secondary battery.

[0118] <19> The wireless power supply system according to any one of <1> to <9> and <15> to <18>, wherein the power receiving device is a hearing aid that is fitted to an ear canal.

[0119] <20> The wireless power supply system according to any one of <1> to <9> and <15> to <19>, wherein the power transmitting device includes a plurality of the recessed housing portions.

[0120] <21> The power transmission device according to any one of <10> to <14>, comprising a plurality of the recessed housing portions.

[0121] 10: Wireless power transfer system 20: Power receiving device 21: Power receiving circuit 22: Power receiving coil 23: Power receiving resonance capacitor 24: Rectification smoothing circuit 25: Charging control circuit 26: Secondary battery 27: Load circuit 30, 30A: Power transmitting device 31: Power transmitting control circuit 32: Switching circuit 33: Power transmitting resonance capacitor 34: Power transmitting coil 200: Power receiving device housing 201: First housing section 202: Second housing section 300: Recess 301: First housing section 302: Second housing section 341, 342: Power transmitting coil 3001, 3002: Recess Ax20: Central axis BT300: Bottom surface DC: Direct current power supply E1: First end E2: Second end F30: Top surface F301, F302: Side surfaces H30, H30A: Power transmission device housing OP300, OP3001, OP3002: Opening S201, S202: Housing orthogonal cross-sectional area PCB: Bottom position PCH: First position PCL: Second position

Claims

1. A resonant wireless power supply system comprising: a power transmitting device having a wireless power transmitting circuit including a power transmitting coil configured using a first annular conductor; and a power receiving device having a wireless power receiving circuit including a power receiving coil configured using a second annular conductor, wherein the power transmitting coil and the power receiving coil form an electromagnetic resonance coupling to wirelessly supply power, wherein the power receiving device has an outer shape with more than eight vertices and comprises a power receiving device housing in which the power receiving coil is disposed, the power transmitting device comprises a power transmitting device housing having a recessed housing portion formed therein that is large enough to accommodate the power receiving device housing, the recessed housing portion having a bottom surface and a side surface extending upright from the bottom surface, and the power receiving device housing is in point contact or line contact at two or more points on the side surface in a first direction that is normal to the bottom surface in a plurality of postures, or at one or more points on each of the bottom surface and the side surface, a first annular conductor having a spiral shape with a first opening, and arranged at a position where the concave accommodating portion is disposed within the first opening, and between an upper end of the power receiving device housing in a accommodated state or the upper end of the concave accommodating portion which is closer to the bottom surface and the bottom surface; the power receiving device housing is accommodated in the concave accommodating portion; and a magnetic flux loop created by the power transmitting coil is linked to the power receiving coil, thereby increasing the magnitude of the electromagnetic resonance coupling.

2. The wireless power supply system of claim 1, wherein the second annular conductor is a spiral having a second opening and is arranged within the power receiving device housing, and the power receiving device housing is accommodated in the recessed housing so that a first central axis of the first annular conductor passes through the second opening of the second annular conductor.

3. The wireless power supply system according to claim 1 or 2, wherein the power transmitting device includes a power transmitting resonant capacitor that forms a resonant circuit with the power transmitting coil, and the power receiving device includes a power receiving resonant capacitor that forms a resonant circuit with the power receiving coil, and the power transmitting coil, the power transmitting resonant capacitor, and the power receiving coil, the power receiving resonant capacitor form the electromagnetic field resonance coupling to perform wireless power supply.

4. A wireless power supply system as described in claim 1 or claim 2, wherein the transmitting coil is arranged between an upper end contact portion among two or more contact portions that is farthest from the bottom surface and the bottom surface, and the receiving coil is arranged between a position on the receiving device housing that is closest to the bottom surface and the upper end contact portion.

5. The wireless power supply system described in claim 4, wherein the transmitting coil is positioned closer to the upper end contact portion than the bottom surface in the first direction, and the receiving coil is positioned closer to the upper end than the lower end when the receiving device housing is accommodated in the recessed accommodation portion.

6. A wireless power supply system as described in any one of claims 1 to 5, wherein the power receiving device housing is accommodated in the recessed accommodation portion so that a first central axis of the first annular conductor and a second central axis of the second annular conductor are parallel to each other.

7. The concave accommodating section comprises: a cylindrical first accommodating section including the upper end and having a constant orthogonal cross-sectional area regardless of position in the first direction; and a cone-shaped second accommodating section communicating with the first accommodating section, having the bottom surface, the accommodating section orthogonal cross-sectional area orthogonal to the first direction increasing as the accommodating section approaches the upper end from the bottom surface in the first direction; the power receiving device housing comprises: a first housing section having a large housing orthogonal cross-sectional area orthogonal to the extension direction of the power receiving device housing; and a second housing section having a small housing orthogonal cross-sectional area; the power receiving device housing is accommodated in the concave accommodating section such that at least a portion of the first housing section is inside the first accommodating section; and in a state in which the power receiving device housing is accommodated in the concave accommodating section, at any position in the first direction, the accommodating section orthogonal cross-sectional area of ​​the first accommodating section is larger than the housing orthogonal cross-sectional area of ​​the first housing section, and the accommodating section orthogonal cross-sectional area of ​​the second accommodating section is larger than the housing orthogonal cross-sectional area of ​​the second housing section. The wireless power supply system according to claim 1 .

8. The wireless power supply system described in claim 7, wherein the transmitting coil is arranged at a position corresponding to the first housing portion in the first direction, and the receiving coil is arranged inside the first housing portion in the first direction.

9. A wireless power supply system according to any one of claims 1 to 8, wherein the position of the first annular conductor and the position of the second annular conductor in the first direction overlap.

10. A power transmission device of a wireless power supply system comprising: a wireless power transmission circuit including a power transmission coil constructed using a first annular conductor; and a power receiving coil housed in a power receiving device housing having an external shape with more than eight vertices, and which wirelessly supplies power by coupling an electromagnetic field excited by the power transmission coil to the power receiving device housing; the power transmission device housing has a concave accommodating section formed therein large enough to accommodate the power receiving device housing; the concave accommodating section has a bottom surface and a side surface erected from the bottom surface, and is shaped so that the power receiving device housing makes point or line contact at two or more points on the side surface or at one or more points on each of the bottom surface and the side surface in a first direction that is normal to the bottom surface in a plurality of postures; and the first annular conductor is of a spiral shape having a first opening, and is positioned so that the concave accommodating section is located within the first opening, and between an upper end of the concave accommodating section and the bottom surface.

11. The power transmitting device according to claim 10, wherein the power transmitting coil is disposed at a position closer to the upper end than to the bottom surface in the first direction.

12. The power transmission device described in claim 11, wherein the concave accommodating portion comprises: a cone-shaped first accommodating portion having the bottom surface and a cross-sectional area perpendicular to the first direction that increases as the distance from the bottom surface to the top end in the first direction increases; and a cylindrical second accommodating portion connected to the first accommodating portion, including the top end, and having a constant cross-sectional area perpendicular to the first direction regardless of the position in the first direction.

13. The power transmitting device according to claim 12, wherein the power transmitting coil is disposed at a position corresponding to the second housing portion in the first direction.

14. The power transmission device according to claim 12 or 13, wherein the first accommodating portion is frustum-shaped, and the second accommodating portion is cylindrical.

15. The wireless power supply system according to any one of claims 1 to 9, wherein the frequency of the magnetic field that generates the electromagnetic resonance coupling is in the 6.78 MHz band or the 13.56 MHz band of the ISM band.

16. A wireless power supply system according to any one of claims 1 to 9 and claim 15, wherein the power receiving device includes a secondary battery in the power receiving device housing, the secondary battery being electrically connected to the wireless power receiving circuit.

17. The wireless power supply system according to claim 16, wherein the secondary battery is a thin battery.

18. The wireless power supply system according to claim 16 or 17, wherein the power receiving device includes a power receiving circuit that is electrically connected to the wireless power receiving circuit and the secondary battery.

19. The wireless power supply system according to any one of claims 1 to 9 and claims 15 to 18, wherein the power receiving device is a hearing aid that is fitted in an ear canal.

20. A wireless power supply system according to any one of claims 1 to 9 and claims 15 to 19, wherein the power transmission device has a plurality of the recessed housing portions.

21. The power transmission device according to any one of claims 10 to 14, comprising a plurality of the recessed accommodating portions.

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