Wireless power transmission system

Abstract

This invention provides a wireless power transmission system that can suppress changes in the electric field between the electrodes on the power transmission device and the electrodes on the power reception device when the power reception device rotates or shifts in position along the surface of the electrodes on the power transmission device, thereby enabling stable wireless power transmission from the power transmission device to the power reception device. [Solution] The wireless power transmission system comprises a power transmitting device and a power receiving device used for wireless power transmission using an electric field coupling method. The power transmitting device has a first transmitting electrode with a porous shape in which a plurality of holes are randomly dispersed, a second transmitting electrode provided independently of the first transmitting electrode at a distance greater than that of the power receiving device, and a power supply that applies a time-varying voltage between the first transmitting electrode and the second transmitting electrode. The power receiving device has a first receiving electrode provided facing the first transmitting electrode of the power transmitting device, and a second receiving electrode provided independently of the first receiving electrode at a distance greater than that of the power transmitting device.

Description

Technical Field

[0001] The present disclosure relates to a wireless power transmission system using an electric field coupling method, and a power transmission device and a power reception device used in the wireless power transmission system.

Background Art

[0002] Conventionally, a wireless power transmission system using an electric field coupling method for transmitting power by electrically coupling an electrode on the power transmission side and an electrode on the power reception side is known.

[0003] Patent Document 1 discloses a power transmission system including a power transmission device (first power transmission device) having an active electrode and a passive electrode, and a power reception device (second power transmission device) having an active electrode and a passive electrode, in which the power transmission device and the power reception device are coupled by a capacitance generated between the active electrodes and a capacitance generated between the passive electrodes. In the power transmission system of Patent Document 1, when the area of the formation region of the active electrode of the power transmission device is represented by Sta, the area of the formation region of the passive electrode of the power transmission device is represented by Stp, the area of the formation region of the active electrode of the power reception device is represented by Sra, and the area of the formation region of the passive electrode of the power reception device is represented by Srp, the relationship is Sta≦Stp, Sra≦Srp. Also, at least one of the active electrodes of the power transmission device and the power reception device has a conductor portion in a frame shape, stripe shape, or lattice shape periodically arranged in the plane direction.

[0004] Patent Document 2 discloses a power transmission system comprising a vertical pair of inner and outer coupling capacitors. In the power transmission system of Patent Document 2, one plate of the outer coupling capacitor at least partially overlaps one plate of the inner coupling capacitor on the primary side, and another plate of the outer coupling capacitor at least partially overlaps another plate of the inner coupling capacitor on the secondary side. In the power transmission system of Patent Document 2, each plate of the outer coupling capacitor has a larger area than each plate of the inner coupling capacitor, the distance between the primary and secondary sides is greater than the distance between the plates of the inner and outer coupling capacitors on the primary and secondary sides respectively, and power is transmitted capacitively through the vertical pair of coupling capacitors. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-070574 [Patent Document 2] International Publication No. 2017 / 165577 Brochure [Overview of the Initiative]

[0006] A wireless power transmission system according to one aspect of the present disclosure comprises a power transmitting device and a power receiving device used for wireless power transmission by electric field coupling. The power transmitting device includes a first transmitting electrode having a porous shape with a plurality of holes randomly dispersed therein, a second transmitting electrode provided independently of the first transmitting electrode at a distance greater from the power receiving device than the first transmitting electrode, and a power supply that applies a time-varying voltage between the first transmitting electrode and the second transmitting electrode. The power receiving device includes a first receiving electrode provided facing the first transmitting electrode of the power transmitting device, and a second receiving electrode provided independently of the first receiving electrode at a distance greater from the power transmitting device than the first receiving electrode.

[0007] In the wireless power transmission system, the size of the first transmitting electrode in the planar direction is less than or equal to the size of the second transmitting electrode in the planar direction, and at least a portion of the second transmitting electrode may face the entire back surface of the first transmitting electrode.

[0008] In the wireless power transmission system, the planar size of the first receiving electrode is less than or equal to the planar size of the second receiving electrode, and at least a portion of the second receiving electrode may face the entire back surface of the first receiving electrode.

[0009] In the wireless power transmission system, the first receiving electrode and the second receiving electrode may each be positioned on the same plane that is inclined with respect to the front surface of the first transmitting electrode, but in positions that do not overlap each other.

[0010] In the wireless power transmission system, the size of the second receiving electrode in the planar direction may be less than or equal to the size of the second transmitting electrode in the planar direction.

[0011] In the wireless power transmission system, the first transmitting electrode may be formed of a porous body having at least a conductive surface. Here, the porous body may be a metallic porous body.

[0012] In the wireless power transmission system, the power transmission device may include a power supply that outputs an AC or DC signal, and a power transmission circuit that generates an AC voltage having a predetermined frequency and amplitude based on the signal output from the power supply and applies the AC voltage between the first transmitting electrode and the second transmitting electrode. The power receiving device may include a power receiving circuit that includes a rectifier circuit for rectifying the AC voltage generated between the first receiving electrode and the second receiving electrode.

[0013] In the wireless power transmission system, the power transmission circuit may include a dielectric constant sensor that detects a change in dielectric constant between the first transmitting electrode and the first receiving electrode, and a control circuit that determines a connection state in which wireless power transmission by electric field coupling between the power transmission device and the power receiving device is possible based on the detection result of the dielectric constant sensor, and controls wireless power transmission from the power transmission device to the power receiving device.

[0014] In the wireless power transmission system, the power transmission circuit may have a communication circuit for communicating with the power receiving device, and the power receiving circuit may have a communication circuit for communicating with the power transmission device. Here, the power transmission circuit may have a control circuit that controls wireless power transmission from the power transmission device to the power receiving device based on communication information transmitted and received between the power transmission device and the power receiving device.

[0015] In the wireless power transmission system, a plurality of power receiving devices may be provided, and the power transmission circuit may have a control circuit that controls wireless power transmission from the power transmission device to the plurality of power receiving devices based on the number of the plurality of power receiving devices.

[0016] In the wireless power transmission system, an inductor may be provided in at least one of the power transmission circuit and the power receiving circuit so as to perform wireless power transmission from the power transmission device to the power receiving device using a resonance phenomenon between at least one of the first transmitting electrode and the second transmitting electrode of the power transmission device and at least one of the first receiving electrode and the second receiving electrode of the power receiving device.

[0017] In the wireless power transmission system, the inductor is a variable inductor, and the power transmission circuit section may have a control circuit that controls wireless power transmission from the power transmission device to the power receiving device by changing the inductance of the variable inductor according to the status of wireless power transmission from the power transmission device to the power receiving device.

[0018] In the wireless power transmission system, the power transmission circuit may include a load switch and a control circuit that controls the load switch to switch the wireless power transmission from the power transmission device to the power receiving device on and off.

[0019] In the wireless power transmission system, the power transmission circuit may include a transmission circuit that generates an AC voltage having a predetermined frequency and amplitude applied to the first and second transmitting electrodes and outputs the AC voltage, a resonant element circuit for resonant power supply by series resonance provided in the signal path from either of the two output terminals of the transmission circuit that output the AC voltage, and a control circuit that controls the resonant element circuit. Here, the resonant element circuit may include a plurality of inductors with different inductances, a changeover switch that switches the plurality of inductors and connects the selected inductor to the signal path from either of the two output terminals, and a load switch provided between the inductor selected by the changeover switch and the first or second transmitting electrode. The control circuit may also control the switching of the inductors by the changeover switch and the on and off of the load switch.

[0020] In the wireless power transmission system, the power transmission circuit may include a transmission circuit that generates an AC voltage having a predetermined frequency and amplitude applied to the first and second transmission electrodes and outputs the AC voltage, a resonant element circuit for resonant power supply by parallel resonance provided between two signal paths of the two output terminals of the transmission circuit that output the AC voltage, and a control circuit that controls the resonant element circuit. Here, the resonant element circuit may include a plurality of inductors with different inductances, a changeover switch that switches the plurality of inductors and connects the selected inductor to one of the two signal paths, and a load switch provided between the inductor selected by the changeover switch and the other of the two signal paths. Furthermore, the control circuit may control the switching of the inductors by the changeover switch and the on and off of the load switch.

[0021] In the wireless power transmission system, the power receiving circuit section may include: a receiving circuit having an output terminal and a ground terminal that outputs a DC voltage rectified by the rectifier circuit; an inductor for resonant power supply by series resonance, provided in the signal path from either the first receiving electrode or the second receiving electrode to the receiving circuit; a DC pass-through circuit having an input terminal connected to the output terminal of the receiving circuit, an external output terminal that outputs a DC voltage to the power supply target, and a charging output terminal; and a charging control circuit and a battery connected between the charging output terminal of the DC pass-through circuit and the ground terminal of the receiving circuit.

[0022] In the wireless power transmission system, the power receiving circuit may include: a receiving circuit having an output terminal and a ground terminal that outputs a DC voltage rectified by the rectifier circuit; an inductor for resonant power supply by parallel resonance, provided between the first receiving electrode and the second receiving electrode and the receiving circuit and two signal paths; a DC pass-through circuit having an input terminal connected to the output terminal of the receiving circuit, an external output terminal that outputs a DC voltage to the power supply target and a charging output terminal; and a charging control circuit and a battery connected between the charging output terminal of the DC pass-through circuit and the ground terminal of the receiving circuit.

[0023] In the wireless power transmission system, the power transmission circuit may include a communication circuit for communicating with an external device, and a control circuit for stopping wireless power transmission from the power transmission device to the power receiving device in response to a request from the external device.

[0024] In the wireless power transmission system, the power transmission circuit may include a transmission circuit that generates an AC voltage having a predetermined frequency and amplitude applied to the first transmitting electrode and the second transmitting electrode, and outputs the AC voltage, and a control circuit that controls the transmission circuit to change at least one of the frequency and amplitude of the AC voltage applied between the first transmitting electrode and the second transmitting electrode, according to the status of wireless power transmission from the power transmission device to the power receiving device.

[0025] In the wireless power transmission system, the power transmission circuit unit may include a control circuit that controls wireless power transmission from the power transmission device to the power reception device using AI (artificial intelligence).

[0026] The program used in the wireless power transmission system of the present disclosure may include a learned model created using machine learning.

Brief Description of Drawings

[0027] [Figure 1] FIG. 1(a) and FIG. 1(b) are explanatory diagrams showing an example of a magnetic field coupling type wireless power transmission system according to a reference example. [Figure 2] FIG. 2(a) and FIG. 2(b) are explanatory diagrams showing an example of an electric field coupling type wireless power transmission system according to a reference example. [Figure 3] FIG. 3 is an explanatory diagram showing an example of a basic configuration of a power transmission device used in the wireless power transmission system according to an embodiment. [Figure 4] FIG. 4(a) and FIG. 4(b) are explanatory diagrams showing an example of a basic configuration of a power reception device used in the wireless power transmission system according to an embodiment, respectively. [Figure 5] FIG. 5(a) and FIG. 5(b) are perspective views and side views showing an example of a basic configuration of the wireless power transmission system according to an embodiment, respectively. [Figure 6] FIG. 6 is a perspective view showing another example of electrode arrangement in the power transmission device and the power reception device of the wireless power transmission system according to an embodiment. [Figure 7] FIG. 7(a) and FIG. 7(b) are explanatory diagrams showing an example of a first transmission electrode of the power transmission device of the wireless power transmission system according to an embodiment, respectively. [Figure 8] FIG. 8 is an explanatory diagram showing an example of an equivalent circuit in the power transmission device and the power reception device of the wireless power transmission system according to an embodiment. [Figure 9] FIG. 9 is an explanatory diagram showing an example of a basic configuration of a power transmission device of a wireless power transmission system according to a reference example. [Figure 10]Figure 10 is an explanatory diagram showing an example of the circuit configuration of a power transmission device according to an embodiment. [Figure 11] Figure 11 is an explanatory diagram showing another example of the circuit configuration of a power transmission device according to the embodiment. [Figure 12] Figure 12 is an explanatory diagram showing yet another example of the circuit configuration of a power transmission device according to the embodiment. [Figure 13] Figure 13 is an explanatory diagram showing an example of the circuit configuration of a power receiving device according to an embodiment. [Figure 14] Figure 14 is an explanatory diagram showing another example of the circuit configuration of the power receiving device according to the embodiment. [Figure 15] Figure 15 is an explanatory diagram showing another example of the circuit configuration of the power receiving device according to the embodiment. [Modes for carrying out the invention]

[0028] Embodiments of this disclosure will be described below with reference to the drawings. Note that each drawing is merely a schematic representation of the shape, size, positional relationships, correspondences, configuration, processing, steps, etc., to the extent that the contents of this disclosure can be understood. Therefore, this disclosure is not limited to the shapes, sizes, positional relationships, correspondences, configurations, processing, steps, and steps exemplified in each drawing. Furthermore, the numerical values ​​exemplified in this disclosure are merely preferred examples, and therefore, this disclosure is not limited to the numerical values ​​exemplified.

[0029] In one embodiment of the electric field coupling type wireless power transmission system of this disclosure, by using a porous first transmitting electrode formed by randomly dispersing multiple holes as the transmitting electrode of the power transmitting device facing the power receiving device, changes in the electric field between the transmitting electrode on the power transmitting device and the receiving electrode on the power receiving device can be suppressed when the power receiving device rotates or shifts in position relative to the power transmitting device. This enables stable wireless power transmission from the power transmitting device to the power receiving device. In particular, stable short-range wireless power transmission can be performed in configurations where the distance between the power transmitting device and the power receiving device is short.

[0030] Figures 1(a) and 1(b) are explanatory diagrams showing an example of a magnetic field coupling type wireless power transmission system according to a reference example. As shown in Figure 1(a), the power transmission device 910 in the magnetic field coupling type wireless power transmission system comprises a transmitting coil 912 wound around a magnetic core 911 and an AC power supply 913 that supplies AC current to the transmitting coil 912. The power receiving device 920 comprises a receiving coil 922 wound around a magnetic core 921. The power supply target 923 is connected to the receiving coil 922. The transmitting coil 912 of the power transmission device 910 and the receiving coil 922 of the power receiving device 920 are arranged to be on the same axis. When AC current is supplied to the transmitting coil 912, the magnetic flux Φ generated in the transmitting coil 912 links with the receiving coil 922 of the power receiving device 920, causing electromagnetic induction between the transmitting coil 912 and the receiving coil 922, so that AC current flows through the receiving coil 922 and power can be supplied to the power supply target 923. However, as shown in Figure 1(b), if the central axis of the transmitting coil 912 of the power transmission device 910 and the central axis of the receiving coil 922 of the power receiving device 920 are misaligned, a portion of the magnetic flux Ψ generated by the transmitting coil 912 does not link with the receiving coil 922, resulting in a problem where the power supplied to the powered device 923 (power supply amount) decreases.

[0031] Figures 2(a) and 2(b) are explanatory diagrams showing an example of a field-coupled wireless power transmission system according to a reference example. As shown in Figure 2(a), the power transmission device 930 in the field-coupled wireless power transmission system of the reference example comprises a pair of transmitting electrodes 931 and 932 arranged side by side on the same plane so as not to overlap, and an AC power supply 933 that applies an AC voltage to the transmitting electrodes 931 and 932. The power receiving device 940 comprises a pair of receiving electrodes 941 and 942 arranged side by side on the same plane so as not to overlap, facing the transmitting electrodes 931 and 932 of the power transmission device 930. The power supply target 943 is connected to the receiving electrodes 941 and 942. When an AC voltage is applied to the transmitting electrodes 931 and 932, an electric field is formed between the transmitting electrodes 931 and 932 and the receiving electrodes 941 and 942. Electrostatic induction through the capacitance between the transmitting electrodes 931 and 932 and the receiving electrodes 941 and 942 generates an AC voltage between the receiving electrodes 941 and 942, allowing power to be supplied to the powered device 943. However, as shown in Figure 2(b), if the central axes of the transmitting electrodes 931 and 932 of the power transmission device 930 and the central axes of the receiving electrodes 941 and 942 of the power receiving device 940 are misaligned, an uncoupled electric field E' is generated between the transmitting electrodes 931 and 932 and the receiving electrodes 941 and 942, resulting in a decrease in the power supplied to the powered device 943 (power supply amount).

[0032] The following embodiments describe a wireless power transmission system (hereinafter also referred to as the "WPT system") that can achieve stable wireless power transmission from a power transmission device to a power receiving device even when the power receiving device rotates or is misaligned relative to the power transmission device. The WPT system in these embodiments may also be a charging system that charges batteries incorporated into terminal devices or vehicles in a contactless manner.

[0033] Figure 3 is an explanatory diagram showing an example of the basic configuration of a power transmission device 10 used in a wireless power transmission system according to an embodiment. In Figure 3, the power transmission device 10 functions as a transmitting station in the WPT system and is a device suitable for short-range wireless power transmission (electric field coupled power transmission) using an electric field coupling method to a power receiving device located at the top of the figure.

[0034] The power transmission device 10 comprises a first transmitting electrode 11 and a second transmitting electrode 12, which are two conductive electrodes that are electrically isolated from each other by DC current, and a power supply 13 that applies a time-varying voltage between the first transmitting electrode 11 and the second transmitting electrode 12. The first transmitting electrode 11 is a porous electrode formed by randomly dispersing a plurality of holes 11A. The second transmitting electrode 12 is an electrode provided independently of the first transmitting electrode 11, at a distance greater than that of the first transmitting electrode 11 from the power receiving device located above in the figure.

[0035] The time-varying voltage applied between the first transmitting electrode 11 and the second transmitting electrode 12 may have any current-voltage characteristics, or it may be a voltage that changes in a time-dependent manner. In the example in Figure 3, the power supply 13 applies, for example, an AC voltage as the time-varying voltage. The frequency of the AC voltage is, for example, a microwave frequency (wavelength: 10 mm to 100 mm), a millimeter wave frequency (wavelength: 1 mm to 10 mm), or a submillimeter wave frequency (wavelength: 0.1 mm to 1 mm).

[0036] All or some of the multiple holes 11A dispersed in the first transmitting electrode 11 may have different shapes or sizes from each other. Furthermore, the shape (opening shape) of the multiple holes 11A in the electrode surface direction may be circular as shown in the figure, or it may be a triangle, square, or polygon with pentagons or more, or it may be an irregular shape with different shapes from each other. Also, the multiple holes 11A are formed randomly and dispersed, for example, so as to be non-periodic in the direction along the electrode surface (one-dimensional or two-dimensional direction). Some of the multiple holes 11A may be formed periodically in the direction along the electrode surface (one-dimensional or two-dimensional direction).

[0037] Here, if we define the conductor filling degree (metal filling degree) α as the proportion of the space in which the first transmitting electrode 11 is located that is occupied by the conductor (metal) (the portion other than the multiple holes), then by adjusting this α, the coupling coefficient (coupling degree), which indicates the degree of electric field coupling between the first transmitting electrode 11 and the receiving electrode on the power receiving device side, can be adjusted. The adjustment of α, i.e., the adjustment of the coupling coefficient (coupling degree), may be performed, for example, by changing the size, shape, density, etc., of the multiple holes 11A dispersed in the first transmitting electrode 11.

[0038] In the example shown in Figure 3, the planar dimensions of the first transmitting electrode 11 and the second transmitting electrode 12 are the same or nearly the same, but the planar dimensions of the first transmitting electrode 11 may be less than or equal to the planar dimensions of the second transmitting electrode 12. Also, in the example shown in Figure 3, the entire second transmitting electrode 12 faces the entire back surface (bottom surface in the figure) of the first transmitting electrode 11, but a part of the second transmitting electrode 12 may face the entire back surface of the first transmitting electrode 11. Furthermore, in the example shown in Figure 3, the electrode surfaces of the first transmitting electrode 11 and the second transmitting electrode 12 are parallel or nearly parallel to each other, but the electrode surface of the second transmitting electrode 12 may be inclined at a predetermined angle with respect to the electrode surface of the first transmitting electrode 11.

[0039] Furthermore, the planar external shape of the first transmitting electrode 11 and the second transmitting electrode 12 may be, for example, a quadrilateral shape (e.g., square, rectangle) as shown in the figure, or a polygonal shape such as a circle, ellipse, oblong, triangle, or pentagon, or any other shape. Also, the first transmitting electrode 11 and the second transmitting electrode 12 may be flat conductors as shown in the figure, or they may be conductors other than flat ones, or they may be three-dimensional conductors.

[0040] In the example shown in Figure 3, it is assumed that the receiving electrode of the power receiving device is located at the top of the figure; however, the receiving electrode of the power receiving device may be located at the bottom of the figure. In this case, the multiple holes are formed on the second transmitting electrode 12, not the first transmitting electrode 11.

[0041] Figures 4(a) and 4(b) are explanatory diagrams showing an example of the basic configuration of a power receiving device 20 used in a wireless power transmission system according to an embodiment. In Figures 4(a) and 4(b), the power receiving device 20 functions as a receiving station in the WPT system and is a device that receives wireless power transmission using an electric field coupling method from a power transmitting device located at the bottom of the figure.

[0042] The power receiving device 20 comprises a first receiving electrode 21 and a second receiving electrode 22, which are two conductive electrodes electrically isolated from each other by DC current, and which are of different sizes. The first receiving electrode 21 is an electrode provided so as to face the first transmitting electrode 11 of the power transmitting device 10 with a predetermined gap. The second receiving electrode 22 is an electrode provided independently of the first receiving electrode 21 at a distance greater from the power transmitting device 10 than the first receiving electrode 21. The received voltage of the alternating current generated between the first receiving electrode 21 and the second receiving electrode 22 by wireless power transmission from the power transmitting device 10 is supplied to the receiver 23.

[0043] In the example shown in Figure 4(a), the size of the first receiving electrode 21 is less than or equal to the size of the second receiving electrode 22, and the first receiving electrode 21 and the second receiving electrode 22 are arranged such that the centers of each electrode lie on the same vertical axis (a virtual axis in the vertical direction). The first receiving electrode 21 and the second receiving electrode 22 are arranged so as not to lie on the same plane (a virtual horizontal plane in the figure). At least a portion of the second receiving electrode 22 faces the entire back surface (the top surface in the figure) of the first receiving electrode 21. The first receiving electrode 21 and the second receiving electrode 22 may also be arranged with a horizontal offset (lateral direction in the figure) so that the centers of each electrode do not lie on the same vertical axis (a virtual axis in the vertical direction). Furthermore, the electrode surfaces of the first receiving electrode 21 and the second receiving electrode 22 are parallel or nearly parallel to each other, but the electrode surface of the second receiving electrode 22 may be inclined by a predetermined angle with respect to the electrode surface of the first receiving electrode 21.

[0044] In the example shown in Figure 4(b), the size of the first receiving electrode 21 is less than or equal to the size of the second receiving electrode 22, and the first receiving electrode 21 and the second receiving electrode 22 are arranged to be on the same plane (a virtual horizontal plane in the figure). However, the arrangement surfaces of the first receiving electrode 21 and the second receiving electrode 22 are positioned on the same plane that is inclined with respect to the front surface (the side facing the power receiving device) of the first transmitting electrode 11 of the power transmission device 10, and are not in positions that overlap each other.

[0045] In Figures 4(a) and 4(b), the planar shape of the first receiving electrode 21 and the second receiving electrode 22 may be, for example, a quadrilateral shape (e.g., square, rectangle) as shown, or a polygonal shape such as a circle, ellipse, oblong, triangle, or pentagon, or any other shape. Furthermore, the first receiving electrode 21 and the second receiving electrode 22 may be flat conductors as shown, or conductors other than flat ones, or three-dimensional conductors.

[0046] Figures 5(a) and 5(b) are a perspective view and a side view, respectively, showing an example of the basic configuration of a wireless power transmission system according to an embodiment. In the example shown in Figures 5(a) and 5(b), a vertically arranged WPT system is configured in which the electrodes are stacked in the thickness direction, with the pair of first transmitting electrodes 11 and second transmitting electrodes 12 of the power transmission device 10 in Figure 3, and the pair of first receiving electrodes 21 and second receiving electrodes 22 of the power receiving device 20 in Figure 4(a) positioned above them.

[0047] Figure 6 is a perspective view showing another example of the basic configuration of a wireless power transmission system according to an embodiment. In the example of Figure 6, a vertically arranged WPT system is configured in which a pair of first receiving electrodes 21 and second receiving electrodes 22 of the power receiving device 20 shown in Figure 4(b) are positioned above a pair of first transmitting electrodes 11 and second transmitting electrodes 12 of the power transmitting device 10 shown in Figure 3.

[0048] In Figures 5(a), 5(b), and 6, the size (area) of the second receiving electrode 22 of the power receiving device 20 may be less than or equal to the size (area) of the first transmitting electrode 11 and the second transmitting electrode 12 of the power transmitting device 10. For example, the size (area) of the second receiving electrode 22 of the power receiving device 20 may be less than or equal to half or one-third of the size (area) of the first transmitting electrode 11 and the second transmitting electrode 12 of the power transmitting device 10. In this case, wireless power can be transmitted simultaneously from a single power transmitting device 10 to two or more power receiving devices 20.

[0049] Figures 7(a) and 7(b) are explanatory diagrams showing examples of the first transmitting electrode 11 of the power transmission device 10 of a wireless power transmission system according to an embodiment. The porous first transmitting electrode 11 of the power transmission device 10 may be, for example, a porous body formed by dispersing a large number of holes (e.g., through holes) 11A in a two-dimensional direction, as shown in Figure 7(a), or a porous body formed by dispersing a large number of holes (e.g., through holes) 11A in a three-dimensional direction, as shown in Figure 7(b). The porous body is made of a material whose surface portion is conductive, and may be, for example, a metallic porous body. The internal spaces that make up the holes of the porous first transmitting electrode 11 may be filled with a medium other than air. In addition, at least one space between and around each electrode 11, 12 of the power transmission device 10, and at least one space between and around each electrode 21, 22 of the power receiving device 20 may be filled with any medium.

[0050] Figure 8 is an explanatory diagram showing an example of an equivalent circuit in the power transmission device 10 and power receiving device 20 of a wireless power transmission system according to an embodiment. In Figure 8, the electric field coupling section 300 between the four electrodes 11, 12, 21, and 22 can be represented by an equivalent circuit consisting of six capacitances C1 to C6. C1 and C2 in the figure are the capacitance between the first transmitting electrode 11 and the first receiving electrode 21 and the capacitance between the second transmitting electrode 12 and the second receiving electrode 22, respectively (also called "junction capacitance" or "coupling capacitance"), and mainly contribute to wireless power transmission. C3 and C4 in the figure are the capacitance between the first transmitting electrode 11 and the second transmitting electrode 12 and the capacitance between the first receiving electrode 21 and the second receiving electrode 22, respectively, and are self-capacitors (also called "parasitic capacitance") that do not contribute to wireless power transmission or hinder power transmission. In the figure, C5 and C6 are the capacitances between the first transmitting electrode 11 and the second receiving electrode 22, and the capacitance between the second transmitting electrode 12 and the first receiving electrode 21, respectively. These are mutual capacitances (also called "parasitic capacitances") that do not contribute to wireless power transmission or hinder power transmission. In this embodiment, by using a porous first transmitting electrode 11 formed by randomly dispersing multiple holes 11A, the capacitance C1 between the first transmitting electrode 11 and the first receiving electrode 21, which contributes to wireless power transmission, is reduced depending on the shape of the porous electrode. In addition, the capacitance C2 between the second transmitting electrode 12 and the second receiving electrode 22 is maintained, while other parasitic capacitances C3, C4, C5, and C6 are suppressed, thereby enabling highly efficient electric field coupled power transmission that is resistant to misalignment.

[0051] According to the WPT system of this embodiment disclosed in Figures 3 to 8, the first transmitting electrode 11 and the second transmitting electrode 12 of the power transmission device 10 can be arranged in overlapping positions, and the first receiving electrode 21 and the second receiving electrode 22 of the power receiving device 20 are arranged in overlapping positions facing the pair of first transmitting electrodes 11 and the second transmitting electrode 12. Since electric field coupled power transmission can be realized using two pairs of parallel plate electrodes in this way, the WPT system can be miniaturized.

[0052] In particular, according to the WPT system of this embodiment, the first transmitting electrode 11 of the power transmission device 10 facing the power receiving device 20 is a porous electrode formed by randomly dispersing a plurality of holes 11A. By using a porous first transmitting electrode 11 formed by randomly dispersing a plurality of holes 11A in this way, strong electric field coupling power transmission becomes possible even with respect to both rotation and displacement of the power receiving device 20 relative to the power transmission device. That is, when the power receiving device 20 rotates or shifts position along the planes of the transmitting electrodes 11 and 12 on the power transmission device 10 side, changes in the electric field (changes in capacitance) between the transmitting electrodes 11 and 12 on the power transmission device side and the receiving electrodes 21 and 22 on the power receiving device 20 side can be suppressed, enabling stable wireless power transmission. Furthermore, constraints on the position and design of the transmitting electrodes of the power transmission device 10 and the receiving electrodes of the power receiving device can be reduced, and the degree of freedom in the position and design of the transmitting electrodes and receiving electrodes can be increased.

[0053] Figure 9 is an explanatory diagram showing an example of the basic configuration of a power transmission device for a wireless power transmission system according to a reference example. Unlike the power transmission device 10 of the WPT system in Figures 3 to 8 according to this embodiment, the power transmission device 10 of the reference example in Figure 9 does not have holes in either the second transmitting electrode 12 or the first transmitting electrode 11' on the passive device side. In the configuration of this reference example, the capacitance C2 (see Figure 8) between the second transmitting electrode 12 and the second receiving electrode 22, which contribute to power transmission by electric field coupling (electric field coupling transmission), decreases, making highly efficient electric field coupling transmission difficult.

[0054] Figure 10 is an explanatory diagram showing an example of the circuit configuration of a power transmission device 10 according to an embodiment. In Figure 10, the power transmission device 10 has a porous first transmitting electrode 11, an arbitrary-shaped second transmitting electrode 12, and a power transmission circuit section 14 and a signal source 15 that constitute the aforementioned power supply 13. The signal source 15 outputs an AC (or DC) signal for generating an AC voltage, which is a time-varying voltage applied between the first transmitting electrode 11 and the second transmitting electrode 12. The power transmission circuit section 14 has a transmitting circuit 141 that generates an AC voltage having a predetermined frequency and amplitude based on the signal output from the signal source 15 and applies the AC voltage between the first transmitting electrode 11 and the second transmitting electrode 12. The transmitting circuit 141 has, for example, an AC / AC conversion function that generates a transmitting signal of an AC voltage having a predetermined frequency and amplitude based on the AC signal output from the signal source 15. The signal source 15 may have arbitrary current-voltage characteristics and may output a voltage that changes depending on time. The signal source 15 may be an AC power supply that generates an AC voltage signal using an oscillator, or a DC stabilized power supply that generates a DC signal. Alternatively, the signal source 15 may be an external signal source (e.g., commercial power supply) that is not provided within the power transmission device 10.

[0055] The power transmission circuit section 14 may include a circuit for transmission control (hereinafter also referred to as the "control circuit"). The control circuit can send control signals to the signal source 15 included in the power transmission device 10, and may control the signal source 15 using these control signals. The control circuit may have a connection confirmation function to confirm the connection (electric field coupling) with the power receiving device 20, a function to control communication with the power receiving device 20, and a negotiation function regarding power transmission (power supply) with the power receiving device 20.

[0056] The first transmitting electrode 11, the second transmitting electrode 12, the power transmission circuit 14, and the signal source 15 constituting the power transmission device 10 may be configured to supply power from a single power transmission device 10 to multiple power receiving devices 20. The power transmission circuit 14 may have a coordinating function to supply power to one or more power receiving devices 20 in cooperation with one or more other power transmission devices. Furthermore, the power transmission device 10 may be equipped with multiple sets of first transmitting electrodes 11 and second transmitting electrodes 12, and when supplying power to multiple power receiving devices 20, one or more sets of first transmitting electrodes 11 and second transmitting electrodes 12 may be used.

[0057] Figure 11 is an explanatory diagram showing another example of the circuit configuration of the power transmission device 10 according to the embodiment. In Figure 11, components common to Figure 10 are denoted by the same reference numerals and their descriptions are omitted. The power transmission circuit section 14 of the power transmission device 10 in Figure 11 has a circuit group 140 including a transmission circuit 141, a control circuit 142, and a communication circuit 143. The communication circuit 143 is a circuit for communicating with the power receiving device 20, other power transmission devices, or a coordinated control device. Here, the coordinated control device is a device that controls multiple power transmission devices to cooperate in supplying power to one or more power receiving devices.

[0058] The control circuit 142 controls, for example, communication between the power receiving device 20, other power transmitting devices, or interoperation control devices via the communication circuit 143, or negotiates with the power receiving device 20, other power transmitting devices, or interoperation control devices regarding wireless power transmission (power supply). For example, the control circuit 142 controls wireless power transmission from the power transmitting device 10 to the power receiving device 20 based on communication information transmitted and received between the power transmitting device 10 and the power receiving device 20.

[0059] The control circuit 142 may also control the transmission circuit 141 to stop wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20 in response to a request from an external device (for example, a power receiving device 20, a linkage control device, or another power transmission device).

[0060] The control circuit 142 may control the transmitting circuit 141 to change at least one of the frequency and amplitude of the AC voltage applied between the first transmitting electrode 11 and the second transmitting electrode 12, depending on the status of wireless power transmission (power supply) from the power transmitting device 10 to the power receiving device 20.

[0061] The functions of the control circuit 142 may be implemented using AI (artificial intelligence). For example, the control circuit 142 may use AI to control wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20.

[0062] If the WPT system includes multiple power receiving devices 20, the control circuit 142 may control the wireless power transmission (power supply) from the power transmission device 10 to the multiple power receiving devices 20 based on the number of power receiving devices 20 included in the WPT system.

[0063] The power transmission circuit 14 includes a dielectric constant sensor 144 as a connection detection means for detecting changes in dielectric constant between the first transmitting electrode 11 and the first receiving electrode 21. The control circuit 142 may determine a connection state that allows for wireless power transmission (power supply) by electric field coupling between the power transmission device 10 and the power receiving device 20 based on the detection result of the dielectric constant sensor 144, and control the wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20.

[0064] In the WPT system of this embodiment, an inductor may be provided in at least one of the power transmission circuit section 14 of the power transmission device 10 and the power receiving circuit section of the power receiving device 20 (described later) so as to perform wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20 using the resonance phenomenon between at least one of the first transmitting electrode 11 and the second transmitting electrode 12 of the power transmission device 10 and at least one of the first receiving electrode 21 and the second receiving electrode 22 of the power receiving device 20.

[0065] Here, the inductor may be a variable inductor. In this case, the control circuit 142 of the power transmission circuit 14 may change the inductance of the variable inductor according to the status of wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20, thereby controlling the wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20.

[0066] Furthermore, in the WPT system of this embodiment, the power transmission circuit 14 is equipped with a load switch, and the control circuit 142 may control the load switch to switch the wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20 on and off. In the power transmission device 10 of this embodiment, the parasitic capacitance between the first transmitting electrode 11 and ground is quite small, so an inductor with a fairly large inductance is required to perform power transmission using the above-mentioned resonance phenomenon (resonant power transmission). Moreover, when resonant power transmission is performed, the energy stored in the inductance connected to the power transmission circuit 14 becomes maximum. Considering the effect of the inductance with an energy maximum during this resonant power transmission, a load switch may be provided between the inductor and the first transmitting electrode 11 to switch the wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20 on and off. The load switch is, for example, turned on during normal wireless power transmission (power supply) and turned off to prevent large currents when the inductor is switched. Furthermore, by using a load switch to turn off wireless power transmission (power supply) in the event of an abnormality, the noise influence from the energy-storing inductance to the ground can be reduced.

[0067] In Figure 11, the power transmission circuit 14 includes a resonant element circuit 145 for resonant power supply by series resonance, provided in the signal path from one of the two output terminals 140a and 140b (output terminal 140a in this example) that output the AC voltage of the transmission circuit 141 to the first transmission electrode 11, and a load switch 146 provided between the resonant element circuit 145 and the first transmission electrode 11. The resonant element circuit 145 includes a plurality of power inductors 1451 and 1452 having different fixed inductances, a variable power inductor 1453 whose inductance can be changed, and a changeover switch 1454. The power inductors 1451 and 1452 and the variable power inductor 1453 are each inductors suitable for high power.

[0068] The changeover switch 1454 switches between several power inductors 1451, 1452, and 1453 based on a control signal from the control circuit 142, and connects the selected power inductor in series to the signal path from the output terminal 140a of the transmitting circuit 141 to the first transmitting electrode 11. In resonant feeding, for example, a series resonant circuit that resonates at the target frequency is formed by the output impedance of the transmitting circuit 141, the power inductor selected by the changeover switch 1454, the coupling capacitances C1 and C2 between the transmitting electrode and the receiving electrode (see Figure 8), and the input impedance of the receiving circuit 241 of the receiving device 20, enabling highly efficient power transmission from the transmitting device 10 to the receiving device 20.

[0069] The load switch 146 is a switch suitable for switching high power on and off, and is provided between each of the multiple power inductors 1451, 1452, and 1453 and the first transmitting electrode 11.

[0070] The control circuit 142 controls the switching of power inductors 1451, 1452, and 1453 by the changeover switch 1454 and the on / off switching of the load switch 146. For example, the control circuit 142 controls the load switch 146 to be on during normal wireless power transmission (power supply) and to be off when inductor switching occurs. The control circuit 142 also controls the load switch 146 to be off in order to stop wireless power transmission (power supply) in the event of an abnormality. Furthermore, depending on the status of wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20, the control circuit 142 controls the wireless power transmission (power supply) from the power transmission device 10 to the power receiving device 20 by changing the inductance of the variable power inductor 1453 when the variable power inductor 1453 is selected.

[0071] Figure 12 is an explanatory diagram showing yet another example of the circuit configuration of the power transmission device 10 according to the embodiment. In Figure 12, components common to Figures 10 and 11 are denoted by the same reference numerals and their descriptions are omitted. The power transmission device 10 in Figure 12 includes a resonant element circuit 145 for resonant power supply by parallel resonance. The resonant element circuit 145 is provided between two signal paths connected to two output terminals 141a and 141b that output the AC voltage of the transmitting circuit 141. In the example of the circuit configuration in Figure 12, a changeover switch 1454 is connected to the signal path from one output terminal 141a of the transmitting circuit 141 to the first transmitting electrode 11, and a load switch 147 is connected to the signal path from the other output terminal 141b to the second transmitting electrode 12. Power inductors 1451, 1452 and a variable power inductor 1453 are connected between the changeover switch 1454 and the load switch 147, respectively. In resonant power supply, for example, the power inductor selected by the changeover switch 1454 resonates with the self-capacitance C3 of the transmitting electrode (see Figure 8), and the inductor of the receiving circuit 241 of the power receiving device 20 resonates with the self-capacitance C4 of the receiving electrode. This forms a parallel resonant circuit capable of resonating at the target frequency in both the transmitting and receiving sections, enabling highly efficient power transmission from the power transmitting device 10 to the power receiving device 20.

[0072] Figure 13 is an explanatory diagram showing an example of the circuit configuration of a power receiving device 20 according to an embodiment. In Figure 13, the power receiving device 20 has at least a pair of first receiving electrodes 21 and second receiving electrodes 22, and a power receiving circuit section 24. The power receiving circuit section 24 includes a receiving circuit 241 which includes a rectifier circuit that rectifies the AC voltage generated between the first receiving electrode 21 and the second receiving electrode 22. The DC current rectified and output by the receiving circuit 241 can be supplied to a battery (internal power source) in the power receiving circuit section 24 for charging, or supplied to an external power source.

[0073] The power receiving circuit section 24 may include a circuit for receiving control (hereinafter also referred to as the "control circuit") and a communication circuit for communicating with the power transmission device 10, etc. The control circuit may have a connection confirmation function to confirm the connection (electric field coupling) with the power transmission device 10, a function to control communication with the power transmission device 10, and a function to negotiate with the power transmission device 10 regarding power transmission (power supply).

[0074] The first receiving electrode 21, the second receiving electrode 22, and the power receiving circuit 24 constituting the power receiving device 20 may be configured to supply power to the power receiving device 20 from multiple power transmitting devices 10. The power receiving circuit 24 may have a coordinating function to receive power from one or more power transmitting devices 10 in cooperation with one or more other power receiving devices 20. Furthermore, the power receiving device 20 may be equipped with multiple sets of first receiving electrodes 21 and second receiving electrodes 22, and when receiving power from multiple power transmitting devices 10, one or more sets of first receiving electrodes 21 and second receiving electrodes 22 may be used.

[0075] The power receiving circuit section 24 of the power receiving device 20 may include a receiving control circuit, an AC-DC conversion circuit, a DC-DC conversion circuit, a battery as a rechargeable internal power source, and a charging control circuit for the battery. The power receiving circuit section 24 may also have a DC pass-through charging function. Furthermore, the power receiving device 20 may have other power receiving functions not limited to electric field coupling (for example, a function to receive power from a wired power source, an energy harvesting device, a photovoltaic power generation device, etc.).

[0076] Figure 14 is an explanatory diagram showing another example of the circuit configuration of the power receiving device 20 according to the embodiment. In Figure 14, components common to Figure 13 are denoted by the same reference numerals and their descriptions are omitted. The power receiving circuit section 24 of the power receiving device 20 in Figure 14 has a circuit group 240 including a receiving circuit 241, a control circuit 242, and a communication circuit 243. The communication circuit 243 is a circuit for communicating with the power transmitting device 10, other power receiving devices, or a linkage control device. Here, the linkage control device is a device that controls multiple power receiving devices to cooperate in receiving power from one or more power transmitting devices.

[0077] The receiving circuit 241 of the power receiving circuit section 24 has an output terminal 240a that outputs a DC voltage rectified by a rectifier circuit and a ground terminal 240b.

[0078] The control circuit 242 controls, for example, communication between the power transmission device 10, other power receiving devices, or interoperation control devices via the communication circuit 243, or negotiates with the power transmission device 10, other power receiving devices, or interoperation control devices regarding wireless power transmission (power supply). For example, the control circuit 242 controls the reception of power from the power transmission device 10 based on communication information transmitted and received between the power transmission device 10 and the power receiving device 20.

[0079] The functions of the control circuit 242 may be implemented using AI (artificial intelligence). For example, the control circuit 242 may use AI (artificial intelligence) to control wireless power transmission (reception) from the power transmission device 10.

[0080] If the WPT system includes multiple power transmission devices 10, the control circuit 242 may control the wireless power transmission (reception) from the multiple power transmission devices 10 to the power receiving device 20 based on the number of multiple power transmission devices 10 included in the WPT system.

[0081] In Figure 14, the power receiving circuit 24 includes a power inductor 244 for resonant power supply by series resonance, which is provided in the signal path from either the first receiving electrode 21 or the second receiving electrode 22 (in this configuration, the first receiving electrode 21) to the receiving circuit 241. In resonant power supply, for example, a series resonant circuit that resonates at the target frequency is formed by the output impedance of the transmitting circuit 141 of the power transmitting device 10, the coupling capacitances C1 and C2 between the transmitting electrode and the receiving electrode (see Figure 8), the power inductor 244, and the input impedance of the receiving circuit 241 of the power receiving device 20, enabling highly efficient power transmission from the power transmitting device 10 to the power receiving device 20.

[0082] The power receiving circuit 24 also includes a DC pass-through circuit 245, a charging control circuit 246, and a battery 247. The DC pass-through circuit 245 has an input terminal 245a connected to the output terminal 240a of the receiving circuit 241, an external output terminal 245b that outputs a DC voltage to the powered device 800, and a charging output terminal 245c. The charging control circuit 246 is connected between the charging output terminal 245c of the DC pass-through circuit 245 and the ground terminal 240b of the receiving circuit 241, and controls the charging of the battery 247. When there is no wireless power transmission from the power transmission device 10, DC power may be supplied from the battery 247 to the powered device 800.

[0083] Figure 15 is an explanatory diagram showing another example of the circuit configuration of the power receiving device 20 according to the embodiment. In Figure 15, components common to Figures 13 and 14 are denoted by the same reference numerals and their descriptions are omitted. In Figure 15, the power receiving circuit section 24 includes a power inductor 244 for resonant power supply by parallel resonance, provided between two signal paths from the first receiving electrode 21 and the second receiving electrode 22 to the receiving circuit 241. In resonant power supply, for example, the power inductor selected by the changeover switch 1454 resonates with the self-capacitance C3 of the transmitting electrode (see Figure 8), and the inductor of the receiving circuit 241 of the power receiving device 20 resonates with the self-capacitance C4 of the receiving electrode. A parallel resonant circuit capable of resonating at the target frequency is formed in each transmitting and receiving section, enabling highly efficient power transmission from the power transmitting device 10 to the power receiving device 20.

[0084] As described above, according to the embodiments of this disclosure, stable wireless power transmission from the power transmission device 10 to the power receiving device 20 can be performed even if the power receiving device 20 rotates or is misaligned relative to the power transmission device 10.

[0085] Furthermore, according to the embodiments of this disclosure, the apparent transmitting electrode of the power transmission device 10 can be a single transmitting electrode, and the apparent receiving electrode of the power receiving device 20 can be a single receiving electrode. Therefore, constraints on the position and design of the transmitting electrode of the power transmission device 10 and the receiving electrode of the power receiving device 20 can be reduced, and the degree of freedom in the position and design of the transmitting electrode and the receiving electrode can be increased.

[0086] Furthermore, according to the embodiments of this disclosure, highly efficient power transmission from the power transmission device 10 to the power receiving device 20 is possible by resonant power supply via a series resonant circuit or a parallel resonant circuit between the power transmission device 10 and the power receiving device 20.

[0087] Furthermore, the wireless power transmission system disclosed herein can perform stable wireless power transmission from the power transmission device to the power reception device even if the power reception device rotates or shifts in position relative to the power transmission device, thus contributing to the achievement of Sustainable Development Goal (SDG) 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0088] The processing steps and components of the power transmission device, power receiving device, and wireless power transmission system described herein can be implemented by various means. For example, these steps and components may be implemented in hardware, firmware, software, or a combination thereof.

[0089] With respect to hardware implementation, means such as processing units used to realize the above processes and components in a physical entity (e.g., various wireless communication devices, Node B, terminals, hard disk drive devices, or optical disc drive devices) may be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, computers, or combinations thereof.

[0090] Furthermore, with respect to the firmware and / or software implementation, means such as processing units used to realize the above-mentioned components may be implemented in the form of a program (e.g., code such as procedures, functions, modules, instructions, etc.) that performs the functions described herein. Generally, any computer / processor-readable medium that clearly embodies the firmware and / or software code may be used to implement means such as processing units used to realize the above-mentioned processes and components as described herein. For example, the firmware and / or software code may be stored in memory in a control device, for example, and executed by a computer or processor. That memory may be implemented inside the computer or processor, or it may be implemented outside the processor. Also, the firmware and / or software code may be stored in a computer or processor-readable medium such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), electrically erasable PROM (EEPROM), flash memory, floppy disks, compact disks (CDs), digital versatile disks (DVDs), magnetic or optical data storage devices, etc. The code may be executed by one or more computers or processors, and the computers or processors may be made to perform functional embodiments as described herein.

[0091] Furthermore, the medium may be a non-temporary recording medium. Also, the program code may be readable and executable by a computer, processor, or other device or machine, and its format is not limited to a specific format. For example, the program code may be source code, object code, or binary code, or it may be a mixture of two or more of these codes.

[0092] Furthermore, the descriptions of embodiments disclosed herein are provided to enable those skilled in the art to manufacture or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein are applicable to other variations without departing from the spirit or scope of the disclosure. Therefore, the disclosure is not limited to the examples and designs described herein, but should be accepted in the broadest sense that conforms to the principles and novel features disclosed herein. [Explanation of Symbols]

[0093] 10: Power transmission equipment 11: First transmitting electrode 11': First transmitting electrode 11A: Hole 12: Second transmitting electrode 13: Power supply 14: Power transmission circuit section 15: Signal source 20: Power receiving device 21: First receiving electrode 22: Second receiving electrode 23: Receiver 24: Power receiving circuit section 140:Circuit group 140a: Output terminal 140b: Output terminal 141: Transmitter Circuit 141a: Output terminal 141b: Output terminal 142: Control circuit 143: Communication Circuit 144: Dielectric Constant Sensor 145: Resonant element circuit 146: Load switch 147: Load switch 240:Circuit group 240a: Output terminal 240b: Ground terminal 241: Receiving circuit 242: Control circuit 243: Communication Circuit 244: Power Inductor 245: DC pass-through circuit 245a: Input terminal 245b: External output terminal 245c: Charging output terminal 246: Charging control circuit 247: Battery 300: Electric field coupling section 800: Power supply target 1451: Power Inductor 1452: Power Inductor 1453: Variable Power Inductor 1454: Changeover switch

Claims

1. A wireless power transmission system, Equipped with a power transmission device and a power receiving device used for wireless power transmission using an electric field coupling method, The aforementioned power transmission device is A first transmitting electrode having a porous shape formed by randomly dispersing multiple holes, A second transmitting electrode is provided at a position further from the power receiving device than the first transmitting electrode, and is provided independently of the first transmitting electrode. The system includes a power supply that applies a time-varying voltage between the first transmitting electrode and the second transmitting electrode, The power receiving device is A first receiving electrode is provided so as to be opposite to the first transmitting electrode of the power transmission device, The device has a second receiving electrode, which is provided independently of the first receiving electrode at a distance greater than that from the power transmission device, A wireless power transmission system characterized by the following features.

2. In the wireless power transmission system of claim 1, The planar size of the first transmitting electrode is less than or equal to the planar size of the second transmitting electrode. At least a portion of the second transmitting electrode faces the entire back surface of the first transmitting electrode. A wireless power transmission system characterized by the following features.

3. In the wireless power transmission system of claim 1, The size of the first receiving electrode is less than or equal to the size of the second receiving electrode. At least a portion of the second receiving electrode faces the entire back surface of the first receiving electrode. A wireless power transmission system characterized by the following features.

4. In the wireless power transmission system of claim 1, The first receiving electrode and the second receiving electrode are each positioned on the same plane that is inclined with respect to the front surface of the first transmitting electrode, and in positions that do not overlap each other. A wireless power transmission system characterized by the following features.

5. In the wireless power transmission system of claim 1, The size of the second receiving electrode is less than or equal to the size of the second transmitting electrode. A wireless power transmission system characterized by the following features.

6. In the wireless power transmission system of claim 1, The first transmitting electrode is formed of a porous material whose surface is conductive, A wireless power transmission system characterized by the following features.

7. In a wireless power transmission system according to any one of claims 1 to 6, The aforementioned power transmission device is A power supply that outputs AC or DC signals, The system includes a power transmission circuit that generates an AC voltage having a predetermined frequency and amplitude based on the signal output from the power supply, and applies the AC voltage between the first transmitting electrode and the second transmitting electrode. The power receiving device is The power receiving circuit section includes a rectifier circuit that rectifies the AC voltage generated between the first receiving electrode and the second receiving electrode. A wireless power transmission system characterized by the following features.

8. In the wireless power transmission system of claim 7, The aforementioned power transmission circuit section is A dielectric constant sensor for detecting changes in dielectric constant between the first transmitting electrode and the first receiving electrode, The system includes a control circuit that, based on the detection results of the dielectric constant sensor, determines a connection state that enables wireless power transmission by electric field coupling between the power transmitting device and the power receiving device, and controls wireless power transmission from the power transmitting device to the power receiving device. A wireless power transmission system characterized by the following features.

9. In the wireless power transmission system of claim 7, The power transmission circuit section has a communication circuit for communicating with the power receiving device. The power receiving circuit section has a communication circuit for communicating with the power transmitting device. A wireless power transmission system characterized by the following features.

10. In the wireless power transmission system of claim 9, The power transmission circuit section includes a control circuit that controls wireless power transmission from the power transmission device to the power receiving device based on communication information transmitted and received between the power transmission device and the power receiving device. A wireless power transmission system characterized by the following features.

11. In the wireless power transmission system of claim 7, The system includes multiple of the aforementioned power receiving devices, The power transmission circuit section includes a control circuit that controls wireless power transmission from the power transmission device to the multiple power receiving devices based on the number of the multiple power receiving devices. A wireless power transmission system characterized by the following features.

12. In the wireless power transmission system of claim 7, An inductor is provided in at least one of the power transmission circuit and the power receiving circuit so as to perform wireless power transmission from the power transmission device to the power receiving device using the resonance phenomenon between at least one of the first transmitting electrode and the second transmitting electrode of the power transmission device and at least one of the first receiving electrode and the second receiving electrode of the power receiving device. A wireless power transmission system characterized by the following features.

13. In the wireless power transmission system of claim 12, The aforementioned inductor is a variable inductor, The power transmission circuit section includes a control circuit that controls wireless power transmission from the power transmission device to the power receiving device by changing the inductance of the variable inductor according to the status of wireless power transmission from the power transmission device to the power receiving device. A wireless power transmission system characterized by the following features.

14. In the wireless power transmission system of claim 12, The aforementioned power transmission circuit section is Load switch and, The system includes a control circuit that controls the load switch to switch the wireless power transmission from the power transmission device to the power receiving device on and off. A wireless power transmission system characterized by the following features.

15. In the wireless power transmission system of claim 12, The aforementioned power transmission circuit section is A transmitting circuit that generates an AC voltage having a predetermined frequency and amplitude applied to the first transmitting electrode and the second transmitting electrode, and outputs the AC voltage, A resonant element circuit for resonant power supply by series resonance is provided in the signal path from one of the two output terminals of the transmitting circuit that output the AC voltage, The circuit includes a control circuit for controlling the aforementioned resonant element circuit, The aforementioned resonant element circuit is Multiple inductors with different inductances, A selector switch that switches between the aforementioned multiple inductors and connects the selected inductor to the signal path from either of the two output terminals, The system includes a load switch provided between the inductor selected by the changeover switch and the first transmitting electrode or the second transmitting electrode, The control circuit controls the switching of the inductor by the changeover switch and the on / off state of the load switch based on the status of wireless power transmission from the power transmission device to the power receiving device. A wireless power transmission system characterized by the following features.

16. In the wireless power transmission system of claim 12, The aforementioned power transmission circuit section is A transmitting circuit that generates an AC voltage having a predetermined frequency and amplitude applied to the first transmitting electrode and the second transmitting electrode, and outputs the AC voltage, A resonant element circuit for resonant power supply by parallel resonance is provided between the two signal paths of the two output terminals of the transmitting circuit that output the AC voltage, The circuit includes a control circuit for controlling the aforementioned resonant element circuit, The aforementioned resonant element circuit is Multiple inductors with different inductances, A changeover switch that switches between the aforementioned plurality of inductors and connects the selected inductor to one of the two signal paths, The system includes a load switch provided between the inductor selected by the changeover switch and the other of the two signal paths, The control circuit controls the switching of the inductor by the changeover switch and the on / off state of the load switch based on the status of wireless power transmission from the power transmission device to the power receiving device. A wireless power transmission system characterized by the following features.

17. In the wireless power transmission system of claim 7, The power receiving circuit section is, A receiving circuit having an output terminal and a ground terminal that output a DC voltage rectified by the rectifier circuit, An inductor for resonant power supply by series resonance is provided in the signal path from either the first receiving electrode or the second receiving electrode to the receiving circuit, A DC pass-through circuit comprising an input terminal connected to the output terminal of the receiving circuit, an external output terminal that outputs a DC voltage to the power supply target, and a charging output terminal, The charging control circuit and battery are connected between the charging output terminal of the DC pass-through circuit and the ground terminal of the receiving circuit. A wireless power transmission system characterized by the following features.

18. In the wireless power transmission system of claim 7, The power receiving circuit section is, A receiving circuit having an output terminal and a ground terminal that output a DC voltage rectified by the rectifier circuit, An inductor for resonant power supply by parallel resonance is provided between the two signal paths from the first receiving electrode and the second receiving electrode to the receiving circuit, A DC pass-through circuit comprising an input terminal connected to the output terminal of the receiving circuit, an external output terminal that outputs a DC voltage to the power supply target, and a charging output terminal, The charging control circuit and battery are connected between the charging output terminal of the DC pass-through circuit and the ground terminal of the receiving circuit. A wireless power transmission system characterized by the following features.

19. In the wireless power transmission system of claim 7, The aforementioned power transmission circuit section is A communication circuit for communicating with external devices, The system includes a control circuit that stops wireless power transmission from the power transmission device to the power receiving device in response to a request from the external device, A wireless power transmission system characterized by the following features.

20. In the wireless power transmission system of claim 7, The aforementioned power transmission circuit section is A transmitting circuit that generates an AC voltage having a predetermined frequency and amplitude applied to the first transmitting electrode and the second transmitting electrode, and outputs the AC voltage, The system includes a control circuit that controls the transmitting circuit to change at least one of the frequency and amplitude of the AC voltage applied between the first transmitting electrode and the second transmitting electrode, depending on the status of wireless power transmission from the power transmitting device to the power receiving device. A wireless power transmission system characterized by the following features.

21. In the wireless power transmission system of claim 7, The power transmission circuit unit has a control circuit that uses AI (artificial intelligence) to control wireless power transmission from the power transmission device to the power receiving device. A wireless power transmission system characterized by the following features.

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