JP7203332B2 - Power transmitting device, power receiving device, and wireless power transmission system - Google Patents

Description

The present disclosure relates to a power transmitting device, a power receiving device, and a wireless power transmission system.

2. Description of the Related Art In recent years, the development of wireless power transmission technology for transmitting power wirelessly, that is, in a contactless manner, to mobile devices such as mobile phones and electric vehicles is underway. Wireless power transmission technology includes methods such as an electromagnetic induction method and an electric field coupling method. Among them, in the electric field coupling type wireless power transmission system, AC power is wirelessly transmitted from a pair of power transmission electrodes to a pair of power reception electrodes while the pair of power transmission electrodes and the pair of power reception electrodes face each other. A wireless power transmission system using such an electric field coupling method is used, for example, for transmitting power from a pair of power transmission electrodes provided on a road surface or a floor surface to a load. Patent Literature 1 discloses an example of a wireless power transmission system based on such an electric field coupling method.

International Publication No. 2013/187102

In the conventional wireless power transmission using the electric field coupling method, electric field leakage occurs around the power transmitting electrode or the power receiving electrode, which may cause malfunctions of peripheral electronic devices. The present disclosure provides a technology capable of suppressing leakage of an electric field around power transmitting electrodes or power receiving electrodes.

A power transmission device according to one aspect of the present disclosure is a power transmission device used in an electric field coupling type wireless power transmission system, and includes a plurality of first power transmission electrodes and a plurality of A second power transmission electrode, a first terminal connected to the plurality of first power transmission electrodes, and a second terminal connected to the plurality of second power transmission electrodes, wherein an alternating current from the first terminal and the second terminal is provided. a power transmission circuit that outputs electric power; a back electrode connected to a point bearing a potential between the potentials.

A power transmission device according to another aspect of the present disclosure is a power transmission device used in an electric field coupling type wireless power transmission system, comprising a plurality of first power transmission electrodes and a plurality of a second power transmission electrode, a back electrode arranged with a gap on the back side of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes, the plurality of first power transmission electrodes, the plurality of second power transmission electrodes a conductive housing containing a power transmission electrode and the back electrode, the housing being connected to the back electrode;

A power receiving device according to still another aspect of the present disclosure is a power receiving device used in an electric field coupling type wireless power transmission system, wherein a plurality of first power receiving electrodes and A plurality of second power receiving electrodes, a first terminal connected to the plurality of first power receiving electrodes, and a second terminal connected to the plurality of second power receiving electrodes, wherein the first terminal and the second terminal a power receiving circuit for converting AC power input from the power receiving circuit into other power and outputting the same; a back electrode connected to a location having a potential between the potential of the first terminal and the potential of the second terminal.

A power receiving device according to still another aspect of the present disclosure is a power receiving device used in an electric field coupling type wireless power transmission system, wherein a plurality of first power receiving electrodes and a plurality of second power receiving electrodes; a back electrode arranged with a gap on the back side of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes; the plurality of first power receiving electrodes; 2 a power receiving electrode, and a conductive housing containing the back electrode, the housing being connected to the back electrode.

Any of the general or specific aspects described above may be implemented in a system, method, integrated circuit, computer program, or recording medium. Alternatively, they may be embodied in any combination of systems, devices, methods, integrated circuits, computer programs and recording media.

According to the technology of the present disclosure, it is possible to suppress the leakage of the electric field around the power transmitting electrode or the power receiving electrode, and reduce the risk of malfunction of peripheral electronic devices.

1 is a diagram schematically showing an example of a wireless power transmission system using an electric field coupling method; FIG. FIG. 10 is a diagram schematically showing another example of a wireless power transmission system using an electric field coupling method; FIG. 10 is a diagram schematically showing another example of a wireless power transmission system using an electric field coupling method; 1 is a diagram showing a schematic configuration of a wireless power transmission system; FIG. FIG. 4 is a diagram showing an example of distribution of an electric field formed around a power transmission electrode during power transmission; 1 is a perspective view schematically showing an example of a wireless power transmission system capable of reducing leakage electric field strength; FIG. 5 is a diagram showing a schematic configuration of the wireless power transmission system shown in FIG. 4; FIG. FIG. 5 is a schematic cross-sectional view for explaining the effect of suppressing a leakage electric field in the system shown in FIG. 4; 1 is a block diagram schematically showing the configuration of a wireless power transmission system according to an embodiment of the present disclosure; FIG. It is a figure which shows typically the structural example of the power inverter circuit by the side of power transmission. FIG. 4 is a diagram schematically showing a configuration example of a power conversion circuit on the power receiving side; FIG. 4 is a diagram showing an example of connection between a back electrode, each side electrode, and a power transmission circuit; It is a figure which shows the structure of the experiment for verifying the effect of this embodiment. It is a figure which shows the structure of the experiment for verifying the effect of this embodiment. It is a figure which shows an experimental result. FIG. 4 is a diagram showing an example of intensity distribution of an electric field formed around power transmission electrodes in a configuration in which each electrode is not divided; 11B is a diagram showing an example of a configuration in which a back electrode is arranged on the back side of the power transmission electrode in the configuration shown in FIG. 11A and an example of electric field intensity distribution in that case; FIG. FIG. 4 is a diagram showing an example of a configuration in which a power transmission electrode is not divided into a plurality of partial electrodes; It is a figure which shows the example of electric field intensity distribution. It is a graph which shows an analysis result. FIG. 4 is a diagram showing a configuration example without a back electrode and an example of electric field strength distribution; 13B is a diagram showing a configuration example in which a back electrode is added to the back side of the power transmission electrode group to the configuration shown in FIG. 13A, and an example of electric field strength distribution in that case; FIG. FIG. 4 is a diagram showing a configuration example with a back electrode and an example of electric field strength distribution; 14B is a diagram showing an example of electric field intensity distribution in the configuration shown in FIG. 14A; FIG. It is a graph which shows an analysis result. FIG. 4 is a diagram showing an example of a configuration in which a back electrode is divided into a plurality of parts; FIG. 10 is a diagram showing an example of a configuration with a single back electrode; It is a figure which shows an analysis result. FIG. 4 is a diagram showing an example of a configuration in which a back electrode is divided into a plurality of parts; It is a figure which shows an analysis result. It is a figure which shows the 1st example of a structure of a power transmission apparatus. FIG. 10 is a diagram showing a second example of the configuration of the power transmission device; FIG. 10 is a diagram illustrating a third example of the configuration of the power transmission device; FIG. 10 is a diagram showing a fourth example of the configuration of the power transmission device; FIG. 12 is a diagram showing a fifth example of the configuration of the power transmission device; FIG. 12 is a diagram showing a sixth example of the configuration of the power transmission device; FIG. 12 is a diagram showing a seventh example of the configuration of the power transmission device; FIG. 12 is a diagram showing an eighth example of the configuration of the power transmission device; FIG. 10 is a diagram showing a modification of the connection between the back electrode and each side electrode and the power transmission circuit; FIG. 10 is a diagram showing another example of a matching circuit in the power transmission device; FIG. 10 is a diagram showing another example of a matching circuit in the power receiving device; It is a figure which shows the example of arrangement|positioning of a power transmission electrode group and a back electrode. FIG. 10 is a diagram showing another arrangement example of the power transmission electrode group and the back electrode;

(Findings on which this disclosure is based)
Prior to describing the embodiments of the present disclosure, knowledge on which the present disclosure is based will be described.

FIG. 1A is a diagram schematically showing an example of a wireless power transmission system using an electric field coupling method. The “electric field coupling method” refers to the method of receiving power from a power transmission electrode group by electric field coupling (hereinafter also referred to as “capacitive coupling”) between a power transmission electrode group including a plurality of power transmission electrodes and a power reception electrode group including a plurality of power reception electrodes. A transmission method in which power is wirelessly transmitted to a group of electrodes. The illustrated wireless power transmission system is a system that wirelessly transmits power to a moving body 10 such as an automated guided vehicle (AGV) used for transporting articles in a factory. In this system, a pair of flat power transmission electrodes 120 a and 120 b are arranged on a floor surface 30 . The moving body 10 includes a pair of power receiving electrodes facing the pair of power transmitting electrodes 120a and 120b. The moving body 10 receives the AC power transmitted from the power transmitting electrodes 120a and 120b by a pair of power receiving electrodes. The received power is supplied to a load such as a motor, a secondary battery, or a storage capacitor of the moving body 10 . Thereby, the mobile body 10 is driven or charged.

FIG. 1A shows XYZ coordinates indicating mutually orthogonal X, Y, and Z directions. The following description uses the XYZ coordinates shown. The direction in which the power transmission electrodes 120a and 120b extend is the Y direction, the direction perpendicular to the surfaces of the power transmission electrodes 120a and 120b is the Z direction, and the direction perpendicular to the Y and Z directions is the X direction. The X direction is the direction in which the power transmission electrodes 120a and 120b are arranged. It should be noted that the orientations of the structures shown in the drawings of the present application are set in consideration of the clarity of explanation, and do not limit the orientations when the embodiments of the present disclosure are actually implemented. Also, the shape and size of all or part of the structures shown in the drawings are not intended to limit the actual shape and size.

In the example of FIG. 1A, the pair of power transmission electrodes 120 are laid on the ground, but the pair of power transmission electrodes 120 may be laid on the side surface of a wall or the like or the top surface of the ceiling or the like. The arrangement and orientation of the power receiving electrodes 220 on the mobile body 10 are determined according to the location and orientation where the power transmitting electrodes 120 are laid.

FIG. 1B shows an example in which power transmission electrodes 120 are laid on the side surface of a wall or the like. In this example, the power receiving electrode 220 is arranged on the side of the moving body 10 . FIG. 1C shows an example in which the power transmission electrodes 120 are installed on the ceiling. In this example, the power receiving electrode 220 is arranged on the top plate of the moving body 10 . As in these examples, there are various variations in the arrangement of power transmitting electrode 120 and power receiving electrode 220 .

FIG. 2 is a diagram showing a schematic configuration of the wireless power transmission system shown in FIGS. 1A to 1C. This wireless power transmission system includes a power transmission device 100 and a mobile object 10 . The power transmission device 100 includes a pair of power transmission electrodes 120a and 120b and a power transmission circuit 110 that supplies AC power to the power transmission electrodes 120a and 120b. The power transmission circuit 110 is, for example, an AC output circuit including an inverter circuit. The power transmission circuit 110 converts DC power supplied from a DC power supply (not shown) into AC power and outputs the AC power to a pair of power transmission electrodes 120a and 120b. A matching circuit may be inserted between the AC output circuit and the power transmission electrodes 120a and 120b to reduce impedance mismatch.

The mobile object 10 includes a power receiving device 200 and a load 320 . The power receiving device 200 includes a pair of power receiving electrodes 220 a and 220 b and a power receiving circuit 210 that converts AC power received by the power receiving electrodes 220 a and 220 b into DC power required by a load 320 and supplies the DC power to the load 320 . The power receiving circuit 210 may include various circuits such as a rectifying circuit or a frequency converting circuit, for example. A matching circuit that reduces impedance mismatch may be inserted between the power receiving electrodes 220a and 220b and the rectifier circuit.

The load 320 is a device that consumes or stores power, such as a motor, a storage capacitor, or a secondary battery. Due to the electric field coupling between the pair of power transmission electrodes 120a and 120b and the pair of power reception electrodes 220a and 220b, power is wirelessly transmitted while the two electrodes face each other. The transmitted power is supplied to load 320 .

Each power transmitting electrode may be placed across the floor rather than parallel to it. For example, when placed on a wall or the like, each power transmitting electrode can be placed substantially perpendicular to the floor surface. Each power receiving electrode in the moving body can also be arranged across the floor so as to face the power transmitting electrode. Thus, the placement of the power receiving electrodes is determined according to the placement of the power transmitting electrodes.

In such an electric field coupling type wireless power transmission system, generally, the capacitance between the power transmitting electrode and the power receiving electrode facing each other is small. Therefore, when transmitting a large amount of power, a high voltage is applied to the power transmitting electrodes 120a and 120b. In that case, the intensity of the electric field leaking around power transmitting electrodes 120a and 120b and power receiving electrodes 220a and 220b also increases.

FIG. 3 is a diagram showing an example of the electric field distribution formed around the power transmission electrodes 120a and 120b during power transmission. In FIG. 3, regions with higher electric field strength are drawn darker. In order to reduce the influence of electromagnetic noise and the like on electronic equipment, it is required to narrow the range of the area distributed around each electrode where the electric field strength is high. For example, it is required that the electric field strength at a position a predetermined distance away from each electrode does not exceed the immunity standard value defined by the electronic device. In addition, in consideration of biological safety, it may be necessary to reduce the leakage electric field strength with the reference value set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) as a target. .

FIG. 4 is a perspective view schematically showing an example of a wireless power transmission system capable of reducing leakage electric field intensity. 5 is a diagram showing a schematic configuration of the wireless power transmission system shown in FIG. 4. FIG. In the systems shown in FIGS. 4 and 5, unlike the systems shown in FIGS. 1A to 2, the power transmission device includes a first power transmission electrode group including a plurality of first power transmission electrodes 120a and a plurality of second power transmission electrodes 120b. and a second power transmission electrode group including. Two first power transmission electrodes 120a and two second power transmission electrodes 120b are alternately arranged at regular intervals in a first direction (X direction in this example) along the surface of each power transmission electrode 120a, 220a. I'm in. The plurality of first power transmission electrodes 120a and the plurality of second power transmission electrodes 120b extend in parallel along the floor surface and are arranged substantially on the same plane.

The power receiving device 200 includes a first power receiving electrode group including a plurality of first power receiving electrodes 220a and a second power receiving electrode group including a plurality of second power receiving electrodes 220b. The two first power receiving electrodes 220a and the two second power receiving electrodes 220b are alternately arranged in one direction (the X direction in FIG. 4). During power transmission, the plurality of first power receiving electrodes 220a face the plurality of first power transmitting electrodes 120a, respectively, and the plurality of second power receiving electrodes 220b face the plurality of second power transmitting electrodes 120b, respectively. In this state, power is wirelessly transmitted from the power transmission device 100 to the mobile object 10 including the power reception device 200 .

The power transmission circuit 110 has two terminals for outputting AC power. One terminal is connected to the two first power transmission electrodes 120a, and the other terminal is connected to the two second power transmission electrodes 120b. When transmitting power, the power transmission circuit 110 applies a first voltage to the two first power transmission electrodes 120a and applies a second voltage opposite in phase to the first voltage to the two second power transmission electrodes 120b. is applied.

FIG. 6 is a schematic cross-sectional view for explaining the effect of suppressing a leakage electric field in this system. The arrows in the figure simply indicate a part of the electric lines of force. FIG. 6 shows the situation at the moment when a positive (+) voltage is applied to each first power transmission electrode 120a and a negative (-) voltage is applied to each second power transmission electrode 120b. At other moments, a negative (-) voltage is applied to each first transmitting electrode 120a and a positive (+) voltage is applied to each second transmitting electrode 120b. In FIG. 6, illustration of electric lines of force on the back side (−Z side) of the power transmission electrodes 120a and 120b is omitted.

As shown in FIG. 6, in this system, two first power transmission electrodes 120a to which a positive voltage is applied and two second power transmission electrodes 120b to which a negative voltage is applied are alternately arranged in the X direction at a given moment. are placed. Therefore, the electric field formed by the first power transmitting electrode 120a having the first voltage and the electric field formed by the second power transmitting electrode 120b having the second voltage of the opposite phase are partially canceled. be. As a result, the strength of the electric field mainly formed above the gap between the first power transmission electrode 120a and the second power transmission electrode 120b is reduced. This effect occurs similarly between any two adjacent electrodes. For this reason, in this embodiment, compared to the case of using two relatively wide power transmission electrodes as shown in FIGS. be able to.

Such an effect can be obtained even when the number of each of the first power transmission electrodes 120a and the number of the second power transmission electrodes 120b is different from two. The number of at least one of the first power transmission electrodes 120a and the second power transmission electrodes 120b should be two or more, and at least part of the first power transmission electrodes and the second power transmission electrodes should be alternately arranged. Also, the number of first power transmission electrodes 120a and the number of second power transmission electrodes 120b may not match. This point also applies to the power receiving electrode group. Also, only one of the power transmitting electrode group and the power receiving electrode group may have the electrode structure as described above.

According to the above system, the electric field intensity around the electrodes can be reduced. came to mind. An outline of the embodiments of the present disclosure will be described below.

A power transmission device according to an aspect of the present disclosure includes a plurality of first power transmission electrodes and a plurality of second power transmission electrodes that are alternately arranged in a first direction along an electrode arrangement surface, and connected to the plurality of first power transmission electrodes. a power transmission circuit including a first terminal and a second terminal connected to the plurality of second power transmission electrodes, the power transmission circuit outputting AC power from the first terminal and the second terminal; and the plurality of first power transmission electrodes and the a back electrode connected to a portion having a potential between the potential of the first terminal and the potential of the second terminal in the power transmission circuit, the back electrode being arranged with a gap on the back side of the plurality of second power transmission electrodes; Prepare.

Here, the "electrode arrangement surface" is not limited to a strictly flat surface, and may be a curved surface. It is not necessary for all transmitting electrodes to be coplanar. This point also applies to the power receiving electrode described later.

“A plurality of first power transmission electrodes and a plurality of second power transmission electrodes that are alternately arranged in a first direction” means that these electrodes are aligned along the first direction with the first power transmission electrodes, the second power transmission electrodes, the It means that they are arranged in the order of the first power transmission electrode and the second power transmission electrode. That is, one second power transmission electrode is arranged between two first power transmission electrodes, and one first power transmission electrode is arranged between two second power transmission electrodes.

The “rear side” means the side opposite to the side where the power receiving device that wirelessly receives power from the power transmitting device is located. The back electrode is connected to a point in the transmission circuit that assumes a potential between the potential of the first terminal and the potential of the second terminal. Therefore, the potential of the back electrode fluctuates with a smaller amplitude than the potential of the first power transmitting electrode and the potential of the second power transmitting electrode during power transmission. By arranging such a back electrode, it is possible to suppress a leakage electric field particularly on the back side of the power transmission electrode. Thereby, for example, the risk of malfunction of peripheral devices can be reduced.

A power transmission device according to another aspect of the present disclosure includes a plurality of first power transmission electrodes and a plurality of second power transmission electrodes that are alternately arranged in a first direction along an electrode arrangement surface, and the plurality of first power transmission electrodes and the plurality of a back electrode arranged with a gap on the back side of the second power transmission electrode; and a conductive housing that houses the plurality of first power transmission electrodes, the plurality of second power transmission electrodes, and the back electrode. and a housing connected to the back electrode.

In this configuration, the back electrode is connected to the conductive housing of the power transmission device. Thereby, when the housing is grounded, for example, the potential fluctuation of the back electrode is significantly smaller than the potential fluctuation of each power transmitting electrode. As a result, the back electrode can effectively suppress the leakage electric field.

In the above configuration, the power transmission device may further include a power transmission circuit that applies AC voltage to the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. At a given moment, a first voltage is applied to the plurality of first power transmitting electrodes, and a second voltage opposite in phase to the first voltage is applied to the plurality of second power transmitting electrodes. A power transmission device is used with a power transmission circuit, but may be manufactured or sold without a power transmission circuit.

The power transmission device of the present disclosure has various structural variations. For example, the following structures are possible.

When viewed from a direction perpendicular to the electrode arrangement surface, the back electrode may overlap at least one of the plurality of gaps between the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. .

The back electrode may be divided into a plurality of parts.

The plurality of portions may be arranged in the first direction or in a second direction crossing the first direction and parallel to the electrode arrangement surface.

When viewed in a direction perpendicular to the electrode arrangement plane, the plurality of portions are aligned in the first direction and are arranged in the plurality of gaps between the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. They may overlap each other.

The plurality of first power transmission electrodes, the plurality of second power transmission electrodes, and the back electrode have a structure extending in a second direction that crosses the first direction and is parallel to the electrode arrangement plane. good too.

The power transmission device is arranged with a gap in the first direction from at least one of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes, and the potential of the first terminal in the power transmission circuit is and the potential of the second terminal, or one or more lateral electrodes connected to the conductive housing.

The side electrodes may be positioned on both sides of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes.

By providing the side electrodes, it is possible to suppress leakage electric fields in the vicinity of the electrodes positioned at the ends of the power transmission electrode group, particularly in the lateral direction. The two side electrodes may be positioned on both sides of the area defined by the power transmission electrode group when viewed from the direction perpendicular to the electrode arrangement surface. In that case, since the electric field strength in the vicinity of the two electrodes at both ends can be reduced, a higher effect can be obtained.

The plurality of first power transmission electrodes and the plurality of second power transmission electrodes may be arranged on the same plane. The side electrode may include a portion protruding from the plane in a direction perpendicular to the plane.

The side electrode may be connected to the back electrode. Also, the side electrodes and the back electrode may be composed of a single conductive member.

The back electrode may be connected to a location in the power transmission circuit where the potential fluctuates with an amplitude less than 10% of the amplitude of the potential fluctuation of the first terminal and the second terminal. Similarly, the side electrode may be connected to a location in the power transmission circuit where the potential fluctuates with an amplitude less than 10% of the potential fluctuation amplitude of the first terminal and the second terminal. The amplitude of the potential fluctuation of the back electrode and the side electrode may be smaller than 5% of the amplitude of the potential fluctuation of the first terminal and the second terminal.

The power transmission circuit may include a matching circuit including the first terminal and the second terminal. The matching circuit includes, for example, a first inductor connected to the first terminal, a second inductor connected to the second terminal, wiring between the first terminal and the first inductor, and the A first capacitor and a second capacitor connected between a second terminal and a wire between the second inductor may be included. The back electrode may be connected to a point between the first capacitor and the second capacitor. The side electrode may also be connected to a point between the first capacitor and the second capacitor.

The above structure can be applied not only to the power transmission device but also to the power reception device. A similar electric field suppression effect can also be obtained in the power receiving device by providing a back electrode. For example, the present disclosure includes the following power receiving device.

A power receiving device according to another aspect of the present disclosure includes a plurality of first power receiving electrodes and a plurality of second power receiving electrodes that are alternately arranged in a first direction along an electrode arrangement surface, and connected to the plurality of first power receiving electrodes. and a second terminal connected to the plurality of second power receiving electrodes, the power receiving circuit converting AC power input from the first terminal and the second terminal into other power and outputting the other power. and a potential between the potential of the first terminal and the potential of the second terminal in the power receiving circuit, which are arranged on the back side of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes with a gap therebetween. a back electrode connected to the point bearing the

“A plurality of first power receiving electrodes and a plurality of second power receiving electrodes that are alternately arranged in a first direction” means that these electrodes are arranged in the first direction in such a manner that the first power receiving electrodes, the second power receiving electrodes, the second power receiving electrodes, the It means that they are arranged in the order of the first power receiving electrode and the second power receiving electrode. That is, one second power receiving electrode is arranged between two first power receiving electrodes, and one first power receiving electrode is arranged between two second power receiving electrodes.

The “rear side” means the side opposite to the side where the power transmitting device is positioned when power is received. The potential of the back electrode fluctuates with a smaller amplitude than the potential of the first power receiving electrode and the potential of the second power receiving electrode during power transmission. By arranging such a back electrode, it is possible to suppress a leakage electric field particularly on the back side of the power receiving electrode. Thereby, for example, the risk of malfunction of peripheral devices can be reduced.

A power receiving device according to still another aspect of the present disclosure includes: a plurality of first power receiving electrodes and a plurality of second power receiving electrodes arranged alternately in a first direction along an electrode arrangement surface; A back electrode arranged with a gap on the back side of the plurality of second power receiving electrodes, and a conductive housing housing the plurality of first power receiving electrodes, the plurality of second power receiving electrodes, and the back electrode. a housing connected to the back electrode.

In this configuration, the back electrode is connected to the conductive housing of the power receiving device. Thereby, when the housing is grounded, for example, the potential fluctuation of the back electrode is significantly smaller than the potential fluctuation of each power receiving electrode. As a result, the back electrode can effectively suppress the leakage electric field.

In the above configuration, the power receiving device further includes a power receiving circuit that converts the AC power received by the plurality of first power receiving electrodes and the plurality of second power receiving electrodes into another form of power (for example, DC power) and outputs the power. may be provided. A power receiving device is used with a power receiving circuit, but may be manufactured or sold without a power receiving circuit.

As for the power receiving device, there are various structural variations as in the case of the power transmitting device. For example, the following structures are possible.

The back electrode may overlap at least one of a plurality of gaps between the plurality of first power receiving electrodes and the plurality of second power receiving electrodes when viewed in a direction perpendicular to the electrode arrangement surface. .

The back electrode may be divided into a plurality of parts.

The plurality of portions may be arranged in the first direction or in a second direction crossing the first direction and parallel to the electrode arrangement surface.

When viewed from a direction perpendicular to the electrode arrangement surface, the plurality of portions are aligned in the first direction and are arranged in the plurality of gaps between the plurality of first power receiving electrodes and the plurality of second power receiving electrodes. They may overlap each other.

The plurality of first power receiving electrodes, the plurality of second power receiving electrodes, and the back electrode have a structure extending in a second direction that crosses the first direction and is parallel to the electrode arrangement plane. good too.

The power receiving device is arranged with a gap in the first direction from at least one of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes, and the potential of the first terminal in the power receiving circuit is and the potential of the second terminal, or at least one lateral electrode connected to the conductive housing.

The side electrodes may be positioned on both sides of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes.

The plurality of first power receiving electrodes and the plurality of second power receiving electrodes may be arranged on the same plane. The side electrode may include a portion protruding from the plane in a direction perpendicular to the plane.

The side electrode may be connected to the back electrode.

In this specification, a group of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes may be referred to as a "power transmission electrode unit". Also, a group of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes may be referred to as a "power receiving electrode unit". These electrode units may comprise sheet-like structures. Each electrode may be inside the sheet-like structure. A conductor pattern formed on a substrate included in the sheet-like structure may be used as each electrode. The sheet-like structure may be, for example, a laminated structure having multiple layers. A back electrode may be provided on one of those layers. In the configuration in which side electrodes are provided, the side electrodes may be provided in a layer different from that of the power transmission electrode or the power reception electrode, or may be provided in the same layer.

A wireless power transmission system according to an aspect of the present disclosure includes the power transmission device according to any one of the aspects described above, and a power reception device that wirelessly receives power from the power transmission device. A wireless power transmission system according to another aspect of the present disclosure includes a power transmission device that wirelessly transmits power and a power reception device according to any one of the aspects described above. A wireless power transmission system may include both the power transmitting device according to any aspect described above and the power receiving device according to any aspect described above.

In some embodiments, the number of first power receiving electrodes is equal to the number of first power transmitting electrodes and the number of second power receiving electrodes is equal to the number of second power transmitting electrodes. In such an embodiment, during power transmission, the plurality of first power receiving electrodes face the plurality of first power transmitting electrodes, and the plurality of second power receiving electrodes face the plurality of second power transmitting electrodes. Electric power is transmitted wirelessly due to the electric field coupling between these opposing electrodes. In order to achieve efficient power transmission, between the power transmitting electrode unit and the power receiving electrode unit, the number of first power transmitting electrodes, the number of second power transmitting electrodes, the number of first power receiving electrodes, and the number of second power receiving electrodes , the width of each electrode, and the placement of each electrode can be designed to match. However, power transfer is possible even if these are not strictly matched. For example, the number of first power receiving electrodes may differ from the number of first power transmitting electrodes, and the number of second power receiving electrodes may also differ from the number of second power transmitting electrodes. Even in that case, it is possible to achieve good power transmission characteristics by appropriately designing the width of each electrode. Further, the width of each of the first power receiving electrode and the width of the second power receiving electrode may be different from the width of each of the first power transmitting electrode and the second power transmitting electrode. Good power transmission can also be achieved by appropriately designing the mutual spacing of the plurality of power transmitting electrodes and the mutual spacing of the plurality of power receiving electrodes arranged in the first direction.

The power receiving device can be mounted, for example, on a mobile object. A “moving object” in the present disclosure is not limited to vehicles as described above, and means any movable object driven by electric power. A mobile object includes, for example, an electric vehicle having an electric motor and one or more wheels. Such vehicles include, for example, automated guided vehicles (AGV) such as the above-mentioned moving bodies, forklifts, overhead hoist transfers (OHT), electric vehicles (EV), electric carts, electric can be in a wheelchair. A "moving object" in the present disclosure also includes a movable object that does not have wheels. For example, bipedal robots, unmanned aerial vehicles (UAVs, so-called drones) such as multicopters, manned electric aircraft, and elevators are also included in the “mobile body”.

Hereinafter, embodiments of the present disclosure will be described more specifically. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art. It is noted that the inventors provide the accompanying drawings and the following description for a full understanding of the present disclosure by those skilled in the art and are not intended to limit the claimed subject matter thereby. Absent. In the following description, constituent elements having the same or similar functions are given the same reference numerals.

(embodiment)
FIG. 7 is a block diagram that schematically illustrates the configuration of a wireless power transmission system according to an exemplary embodiment of the present disclosure; This wireless power transmission system includes a power transmission device 100 and a power reception device 200 . The power receiving device 200 can be mounted on a moving object 10 as shown in FIGS. 1A to 1C and 4, for example.

The power transmission device 100 includes a power transmission circuit 110, a plurality of first power transmission electrodes 120a, a plurality of second power transmission electrodes 120b, two side electrodes 140, and a back electrode . The first power transmission electrodes 120a and the second power transmission electrodes 120b are alternately arranged along one direction along the electrode arrangement surface. Hereinafter, the first power transmission electrode 120a and the second power transmission electrode 120b may be collectively referred to as the "power transmission electrode group 120". The back electrode 130 is arranged on the back side of the first power transmission electrode 120a and the second power transmission electrode 120b with a gap therebetween. The two side electrodes 140 are located on both sides of the power transmission electrode group 120 . More specifically, the first power transmission electrode 120a and the second power transmission electrode 120b located at both ends of the power transmission electrode group 120 are arranged outside with a gap therebetween.

The power transmission circuit 110 includes first terminals 111 connected to the plurality of first power transmission electrodes 120a, and second terminals 112 connected to the plurality of second power transmission electrodes 120b. The power transmission circuit 110 outputs AC power from the first terminal 111 and the second terminal 112 . The back electrode 130 is connected to a point 113 having a potential between the potential of the first terminal 111 and the potential of the second terminal 112 in the power transmission circuit 110 . Each side electrode 140 is similarly connected to a point 113 having a potential between the potential of the first terminal 111 and the potential of the second terminal 112 in the power transmission circuit 110 .

The power transmission circuit 110 in this embodiment includes a power conversion circuit 170 and a matching circuit 180 . The power conversion circuit 170 includes, for example, an inverter circuit that converts the DC power output from the external power supply 310 into AC power. The matching circuit 180 is a circuit that matches the impedances of the power conversion circuit 170 and the power transmission electrode group 120 . In the present embodiment, the rear electrode 130 and the side electrodes 140 are connected to a portion of the matching circuit 180 where the potential fluctuation is relatively small. It should be noted that the back electrode 130 and the side electrodes 140 may be connected to a conductive housing included in the power transmission device 100 instead of a portion in the matching circuit 180 where the potential fluctuation is small. In a configuration in which the housing is grounded, potential fluctuations of the rear electrode 130 and the side electrodes 140 can be effectively suppressed by connecting the rear electrode 130 and the side electrodes 140 to the housing.

The power receiving device 200 includes a power receiving circuit 210 , multiple first power receiving electrodes 220 a , multiple second power receiving electrodes 220 b , two side electrodes 240 , and a back electrode 230 . The first power receiving electrodes 220a and the second power receiving electrodes 220b are alternately arranged along one direction along the electrode arrangement surface of the power receiving device 200 . Hereinafter, the first power receiving electrode 220a and the second power receiving electrode 220b may be collectively referred to as "power receiving electrode group 220". The back electrode 230 is arranged on the back side of the first power receiving electrode 220a and the second power receiving electrode 220b with a gap therebetween. The two side electrodes 240 are positioned on both sides of the power receiving electrode group 220 . More specifically, the first power receiving electrode 220a and the second power receiving electrode 220b located at both ends of the power receiving electrode group 220 are arranged outside with a gap therebetween.

The power receiving circuit 210 includes first terminals 211 connected to the plurality of first power receiving electrodes 220a and second terminals 212 connected to the plurality of second power receiving electrodes 220b. The power receiving circuit 210 converts AC power input from the first terminal 211 and the second terminal 212 into other power such as DC power and outputs the converted power. The back electrode 230 is connected to a point 213 having a potential between the potential of the first terminal 211 and the potential of the second terminal 212 in the power receiving circuit 210 . Each side electrode 240 is similarly connected to a point 213 having a potential between the potential of the first terminal 211 and the potential of the second terminal 212 in the power receiving circuit 210 .

The power receiving circuit 210 in this embodiment includes a power conversion circuit 270 and a matching circuit 280 . The power conversion circuit 270 includes, for example, a rectification circuit that converts AC power input from the power receiving electrode group 220 into DC power. The matching circuit 280 is a circuit that matches the impedances of the power conversion circuit 270 and the power receiving electrode group 220 . In the present embodiment, the back electrode 230 and the side electrodes 240 are connected to a location within the matching circuit 280 where the potential fluctuation is relatively small. Note that the back electrode 230 and the side electrodes 240 in the power receiving device 200 may be connected to a conductive housing included in the power receiving device 200 instead of a location in the power receiving circuit 210 where the potential fluctuation is small. In a configuration where the housing is grounded, potential fluctuations of the rear electrode 230 and the side electrodes 240 can be effectively suppressed by connecting the rear electrode 230 and the side electrodes 240 to the housing.

Each of power transmitting electrodes 120a and 120b, power receiving electrodes 220a and 220b, back electrodes 130 and 230, side electrodes 140 and 240, the housing of power transmitting device 100, and the housing of power receiving device 200 is made of any conductive material. obtain. For example, conductive materials such as aluminum, copper, iron, or alloys may be used.

In the example shown in FIG. 7 , power receiving device 200 further includes charge/discharge control circuit 290 and power storage device 330 . The power storage device 330 is a device that stores power, such as a secondary battery or a capacitor for power storage. The power receiving circuit 210 converts the AC power received by the power receiving electrode group 220 into a voltage required by the power storage device 330 and a load such as an electric motor (not shown), such as a predetermined DC voltage, and outputs the converted voltage. Charge/discharge control circuit 290 is a circuit that controls charging and discharging of power storage device 330 . Charge/discharge control circuit 290 supplies power to power storage device 330 while monitoring the voltage and state of charge (States Of Charge: SOC) of power storage device 330 until the voltage reaches a predetermined value. Thereby, charging of power storage device 330 is realized. Powered device 200 may also include other components not shown, such as motor control circuitry and drive wheels.

FIG. 8A is a diagram schematically showing a configuration example of the power conversion circuit 170. As shown in FIG. In this example, the power conversion circuit 170 has a full-bridge inverter circuit including four switching elements (for example, transistors such as IGBTs or MOSFETs) and a power transmission control circuit 160 . The power transmission control circuit 160 includes a gate driver that outputs a control signal for controlling the on (conducting) and off (non-conducting) states of each switching element, and a processor such as a microcontroller (microcomputer) that causes the gate driver to output the control signal. and Instead of the illustrated full-bridge inverter circuit, a half-bridge inverter circuit or other oscillator circuit such as class E may be used.

The power transmission circuit 110 may include a modulation/demodulation circuit for communication and various sensors for measuring voltage/current. When a modulation/demodulation circuit for communication is provided, data can be superimposed on AC power and transmitted to the power receiving device 200 . If the power supply 310 is an AC power supply, the power conversion circuit 170 converts the input AC power into another form of AC power having a different frequency or voltage.

The power source 310 is, for example, a commercial power source, a primary battery, a secondary battery, a solar cell, a fuel cell, a USB (Universal Serial Bus) power source, a high-capacity capacitor (eg, an electric double layer capacitor), or a voltage converter connected to a commercial power source. It can be any power source such as a device. Although the power supply 310 is a DC power supply in this embodiment, it may be an AC power supply.

The frequency of power transmission may be set, for example, between 50 kHz and 300 GHz, in some examples between 20 kHz and 10 GHz, in other examples between 79 kHz and 20 MHz, and in still other examples between 79 kHz and 14 MHz.

FIG. 8B is a diagram schematically showing a configuration example of the power conversion circuit 270 on the power receiving side. In this example, power conversion circuit 270 is a full-wave rectifier circuit including a diode bridge and a smoothing capacitor. The power conversion circuit 270 may have other rectifier configurations, such as a half wave rectifier circuit or a voltage doubler rectifier circuit. The power conversion circuit 270 may include various circuits such as a constant voltage/constant current control circuit and a modulation/demodulation circuit for communication, in addition to the rectifier circuit. Power conversion circuit 270 converts the AC energy it receives into DC energy that load 320 can use.

The sizes of the housing of the moving body 10, the power transmitting electrodes 120a and 120b, and the power receiving electrodes 220a and 220b are not particularly limited, but can be set to the following sizes, for example. The length (size in the Y direction) of the power transmission electrodes 120a and 120b can be set within a range of 50 cm to 20 m, for example. The width (size in the X direction) of each of the power transmission electrodes 120a and 120b can be set within a range of 0.5 cm to 1 m, for example. When the side electrodes 140 are arranged on at least one side of the power transmitting electrode group, the width can be set within a range of 0.5 mm to 200 mm, for example. Each size of the housing of the moving body 10 in the advancing direction and the lateral direction can be set within a range of 20 cm to 5 m, for example. The length (size in the traveling direction) of each of the power receiving electrodes 220a and 220b can be set within a range of 5 cm to 2 m, for example. The width (size in the lateral direction) of each of the power receiving electrodes 220a and 220b can be set within a range of 0.5 cm to 1 m, for example. When the side electrode 240 is arranged on at least one side of the power receiving electrode group, the width can be set within a range of 0.5 mm to 200 mm, for example. The gap between power transmitting electrodes and the gap between power receiving electrodes can be set within a range of 1 mm to 40 cm, for example. However, it is not limited to these numerical ranges.

In this embodiment, the length of the power transmission electrodes 120a and 120b is greater than the size of the housing of the moving body 10 in the traveling direction. For example, the length of the power transmission electrodes 120a and 120b may be two to 100 times the size of the housing of the mobile body 10 in the traveling direction. In one example, the length of the power transmitting electrodes 120a and 120b may be 5 times or more and 20 times or less than the size of the housing of the mobile object 10 in the traveling direction. Thus, by using the power transmission electrode group 120 that is significantly longer than the size of the housing of the mobile body 10, charging can be performed while the mobile body 10 is moving.

FIG. 9 is a diagram showing an example of connection between the back electrode 130 and each side electrode 140 and the power transmission circuit 110. As shown in FIG. In this example, a power transmitting electrode group 120 , a back electrode 130 and two side electrodes 140 are arranged in a power transmitting electrode sheet 150 . The power receiving electrode group 220 is arranged inside the power receiving electrode sheet 250 . Note that FIG. 9 omits illustration of components of the power receiving device 200 other than the power receiving electrode sheet 250 .

In this example, the matching circuit 180 has a first terminal 180a and a second terminal 180b. The matching circuit 180 includes a first inductor Lt1 connected to the first terminal 180a, a second inductor Lt2 connected to the second terminal 180b, wiring between the first terminal 180a and the first inductor Lt1, and a second inductor Lt1. It includes a first capacitor Ct1 and a second capacitor Ct2 connected between the two terminals 180b and the wiring between the second inductor Lt2. The matching circuit 180 in this example further includes a third capacitor Ct3, a fourth capacitor Ct4, and a third inductor Lt3. The third capacitor Ct3 is connected between the first inductor Lt1 and one of the output terminals of the power conversion circuit 170 as a series circuit element. The fourth capacitor Ct4 is connected between the second inductor Lt2 and the other output terminal of the power conversion circuit 170 as a series circuit element. The third inductor Lt3 is connected as a parallel circuit element between the wiring between the first inductor Lt1 and the third capacitor Ct3 and the wiring between the second inductor Lt2 and the fourth capacitor Ct4. The back electrode 130 is connected to a point between the first capacitor Ct1 and the second capacitor Ct2. Also, each side electrode 140 is connected to the back electrode 130 and indirectly connected to the above point between the first capacitor Ct1 and the second capacitor Ct2.

In this specification, reference symbols such as Lt1 and Lt2 representing inductors are also used as symbols representing inductance values of the inductors. Similarly, a reference number such as Ct1 representing a capacitor is also used as a symbol representing the capacitance value of that capacitor.

The capacitances of capacitors Ct1 and Ct2 can be set to values that are the same or close to each other. The inductances of inductances Lt1 and Lt2 can also be set to the same or close to each other. Capacitances of capacitances Ct3 and Ct4 may similarly be set to values that are the same or close to each other.

According to such a configuration, potential fluctuations of the back electrode 130 and the side electrodes 140 are suppressed during power transmission. Therefore, the electric field in the vicinity of the power transmission electrode group 120 can be effectively suppressed, and the risk of leakage current or electric leakage can be reduced.

Note that the configuration of the matching circuit 180 shown in FIG. 9 is merely an example, and the configuration of the matching circuit 180 is appropriately selected according to required power transmission characteristics. Moreover, if there is no need for impedance matching between the power conversion circuit 170 and the power transmission electrode group 120, the matching circuit 180 may be omitted. In that case, the back electrode 130 and each side electrode 140 can be connected to a location within the power conversion circuit 170 where the potential fluctuation is relatively small.

Although not shown in FIG. 9, the connection between the back electrode 230 and the side electrodes 240 in the power receiving device 200 and the power receiving circuit 210 can also be realized with a similar configuration.

Next, the results of experiments conducted to confirm the effect of suppressing the leakage electric field according to this embodiment will be described.

FIG. 10A is a diagram showing the configuration of this experiment. In this experiment, the power transmitting electrode sheet 150 and the power receiving electrode sheet 250 were placed on the support base 400 in a state perpendicular to the horizontal plane as shown in FIG. 10A. In this state, electric field measuring device 420 measured the strength of the electric field generated around each electrode when power was transmitted from power transmitting electrode sheet 150 to power receiving electrode sheet 250 . The measurement was performed at 15 locations around the electrode by changing the position of the electric field measuring device 420 as shown in FIG. 10B. Experiments were conducted for the following three configurations (a) to (c).
(a) A configuration in which the back electrode 130 is not provided (b) As shown in FIG. ) A configuration in which the back electrode 130 is provided, but the back electrode 130 is not connected to any part of the power transmission circuit 110

FIG. 10C is a diagram showing the results of this experiment. In FIG. 10C, the "observation point" numbers on the horizontal axis correspond to the numbers shown in FIG. 10B. The vertical axis indicates the strength of the leakage electric field. As shown in FIG. 10C , by providing the back electrode 130 , the leakage electric field intensity is reduced on all of the back side, the side side, and the front side of the power transmission electrode sheet 150 . In particular, by connecting the back electrode 130 and the midpoint of the electric potential of the power transmission circuit 110 as in the present embodiment, it can be seen that the effect of suppressing the leakage electric field on the back side is enhanced.

The effect of providing the back electrode 130 is that, as in the example shown in FIG. It can also be obtained in configuration.

FIG. 11A is a diagram showing an example of intensity distribution of an electric field formed around power transmitting electrodes 120a and 120b in a configuration in which each electrode is not divided. With the configuration of power transmitting electrodes 120a and 120b shown in the upper diagram of FIG. 11A, the electric field intensity distribution shown in the lower diagram of FIG. 11A is obtained.

FIG. 11B is a diagram showing an example of a configuration in which the back electrode 130 is arranged on the back side of the power transmission electrodes 120a and 120b in the configuration shown in FIG. 11A, and an example of the electric field intensity distribution in that case. In this example as well, the back electrode 130 is connected to the potential midpoint of the power transmission circuit 110 .

As can be seen from these figures, even in a configuration in which the power transmission electrodes 120a and 120b are not divided into a plurality of partial electrodes, the provision of the back electrode 130 can reduce the electric field strength on the back side.

Next, changes in the electric field suppression effect when the width of the back electrode 130 is changed will be described.

FIG. 12A shows an example of a configuration in which the power transmitting electrodes 120a, 120b are not divided into multiple partial electrodes. The inventors confirmed how the electric field intensity observed at the position of the observation line shown in FIG. 12B changes when the width 2W _BG of the back electrode 130 is changed in the configuration shown in FIG. 12A. We performed an analysis to FIG. 12C is a graph showing the results of the analysis. FIG. 12C shows examples of electric field strength distributions in observation lines when the width 2W _BG of the back electrode 130 is set to 5 mm, 50 mm, 100 mm, and 400 mm. As can be seen from FIG. 12C, the greater the width of the back electrode 130, the greater the reduction in electric field strength.

13A and 13B show examples of electric field strength distributions in an example in which two first power transmission electrodes 120a and two second power transmission electrodes 120b are arranged alternately. FIG. 13A shows a configuration example without the back electrode 130 and an example of electric field intensity distribution. FIG. 13B shows a configuration example in which a back electrode 130 is added to the back side of the power transmission electrode group 120 in addition to the configuration shown in FIG. 13A, and an example of electric field intensity distribution in that case. As can be seen from these figures, the splitting of the electrodes suppresses leakage fields in the region above the gap between two adjacent electrodes. Furthermore, by providing the back electrode 130, the leakage electric field on the back side can be greatly reduced.

The inventors conducted an analysis to confirm the change in the electric field strength on the back side when the width of the back electrode 130 is changed also in the configuration shown in FIG. 13B. In the configuration shown in FIG. 14A, it was confirmed how the electric field strength observed at the position of the observation line shown in FIG. 14B changes when the width 2W _BG of the back electrode 130 is changed. FIG. 14C is a graph showing the results of the analysis. FIG. 14C shows examples of electric field intensity distributions in observation lines when the width 2W _BG of the back electrode 130 is set to 5 mm, 50 mm, 100 mm, and 400 mm, respectively. As can be seen from FIG. 14C, also in this example, the greater the width of the back electrode 130, the greater the reduction in electric field intensity.

As described above, by providing the back electrode 130 and setting the potential of the back electrode 130 to be between the potential of the first power transmission electrode 120a and the potential of the second power transmission electrode 120b, the power transmission electrode group The leakage field on the back side of 120 can be reduced. A similar effect is obtained when a similar back electrode 230 is arranged on the back side of the power receiving electrode group 220, that is, on the side opposite to the side where the power transmitting electrode group 120 is located. The same applies to the configuration in which the back electrode 130 is connected to the grounded conductive housing of the power transmitting device 100 and the configuration in which the back electrode 230 is connected to the grounded conductive housing of the power receiving device 200. effect is obtained.

The above effects can be obtained even when the back electrode 130 is divided into a plurality of parts. The electric field suppression effect in an example in which the back electrode 130 is divided into a plurality of portions will be described below.

FIG. 15A is a diagram showing an example of a configuration in which the back electrode 130 is divided into a plurality of parts. In this example, the multiple portions of the back electrode 130 are arranged in the same first direction as the arrangement direction of the power transmission electrodes 120a and 120b. When viewed in a direction perpendicular to the electrode arrangement plane, the plurality of portions are arranged so as to overlap the plurality of gaps between the plurality of first power transmission electrodes 120a and the plurality of second power transmission electrodes 120b. In this example, the back electrode 130 is divided into three parts. The number of divisions of the back electrode 130 may be different from three.

The inventors conducted an analysis to confirm changes in the electric field strength when the width W _GC of the central portion of the back electrode 130 shown in FIG. 15A is changed. In this analysis, the width W _GS of the two portions on both sides of the back electrode 130 shown in FIG. 15A was fixed at 135 mm. For comparison, as shown in FIG. 15B, the electric field strength was also analyzed for the configuration in which the back electrode 130 was not divided. The electric field strength was compared on the observation line as in the example shown in FIG. 14B.

FIG. 15C shows the results of this analysis. It was confirmed that under the condition that the width W _GS of both end portions of the back electrode 130 was fixed at 135 mm, the electric field strength at the central portion on the back side decreased as the width W _GC of the center portion increased.

The present inventors also confirmed the change in the electric field strength when the width W _GC of the central portion is fixed and the width W _GS of both side portions is changed so as to spread toward the central side, as shown in FIG. 16A. bottom. FIG. 16B shows examples of the electric field intensity at the observation line in the configurations with widths W _GS of 40 mm, 135 mm, 160 mm, and 210 mm, and in the configuration shown in FIG. 15B. As shown in FIG. 15B, under the condition that the width W _GC of the central portion of the back electrode 130 is fixed, the more the width W _GS of the two portions on both sides approaches the inner side, the more effectively the leakage electric field is suppressed. In particular, under the two conditions of W _GS of 160 mm and 210 mm, it was confirmed that the electric field suppression effect in the outer portion on the back side is higher than in the case of using the single back electrode 130 shown in FIG. 15B.

Next, a modified example of this embodiment will be described.

In the example shown in FIG. 7 , the power transmission device 100 includes a back electrode 130 and two side electrodes 140, but the side electrodes 140 may not be provided. Alternatively, the side electrode 140 may be arranged only on one side of the power transmission electrode group 120 . Likewise, the power receiving device 200 does not have to include the side electrode 240 . Alternatively, the side electrode 240 may be arranged only on one side of the power receiving electrode group 220 . Alternatively, only one of the power transmitting device 100 and the power receiving device 200 may include the back electrode. Each back-electrode may be divided into multiple portions, as described above.

FIG. 17A is a diagram showing an example of a configuration in which power transmission device 100 does not include side electrodes 140 . Also in such a configuration, since the back electrode 130 is arranged, it is possible to suppress the leakage electric field on the back side of the electrode.

FIG. 17B is an example in which the power transmission device 100 does not include the side electrode 140 and the back electrode 130 is divided into a plurality of parts. Thus, even if the back electrode 130 is divided into a plurality of parts, the leakage electric field on the back side can be suppressed as described above.

FIG. 17C shows an example in which two side electrodes 140 are spaced apart on both sides of the power transmitting electrode group 120 . In this example, when viewed from the back side, the single back electrode 130 covers the area where the power transmitting electrode group 120 and the two side electrodes 140 are arranged.

FIG. 17D shows an example in which the power transmission device 100 includes two side electrodes 140 and the back electrode 130 is divided into multiple parts. In this example, multiple portions of the back electrode 130 cover the gaps between the power transmitting electrode group 120 and the two side electrodes 140 when viewed from the back side.

17E and 17F show another example in which the power transmission device 100 includes two side electrodes 140 on both sides of the power transmission electrode group 120. FIG. In these examples, each side electrode 140 includes a portion protruding in a direction perpendicular to the plane on which the first power transmission electrode 120a and the second power transmission electrode 120b are arranged. According to such a structure, the effect of suppressing the leakage electric field on the side of the power transmission electrode group 120 is improved.

17G and 17H show the back electrode 130 and side electrode 140 connected to form a single structure. The back electrode 130 and the side electrodes 140 may be made of the same conductive material, or may be made of different conductive materials. Multiple slits may be formed in the bottom of the single structure, as in the example of FIG. 17H.

FIG. 18 is a diagram showing a modification of the connection between the back electrode 130 and the side electrodes 140 and the power transmission circuit 110. As shown in FIG. In this example, each of the back electrode 130 and the side electrode 140 is directly connected to the midpoint of the potential in the power transmission circuit 110 . Such a configuration may be employed, or the side electrode 140 may be indirectly connected to the midpoint potential via the back electrode 130 as in the example shown in FIG.

19A is a diagram showing another example of matching circuit 180 in power transmission device 100. FIG. FIG. 19B is a diagram showing another example of matching circuit 280 in power receiving device 200 . In these examples, matching circuits 180 and 280 have transformers and are configured to step up or step down. In the example of FIG. 19A, power transmission electrodes 120a and 120b are connected to two input terminals T1 and T2 from which AC power is output, respectively, and a terminal Tc having a potential intermediate between the potentials of the two terminals T1 and T2 A back electrode 130 and a side electrode 140 are connected. In the example of FIG. 19B, power receiving electrodes 220a and 220b are connected to two input terminals R1 and R2, respectively, and a back electrode 230 and a side electrode 230 are connected to a terminal Rc having a potential intermediate between the potentials of the two terminals R1 and R2. 240 are connected.

In power transmission device 100 , back electrode 130 and side electrode 140 may be connected to the conductive housing of power transmission device 100 instead of the midpoint of the potential of power transmission circuit 110 . Also in power receiving device 200 , back electrode 230 and side electrode 240 may be connected to the conductive housing of power receiving device 200 instead of the potential midpoint of power receiving circuit 210 . Even with such a configuration, similar effects can be obtained when the housing is grounded.

20A and 20B are diagrams showing an arrangement example of the power transmission electrode group 120 and the back electrode 130. FIG. In the example of FIG. 20A, both the power transmitting electrode group 120 and the back electrode 130 have a sheet-like structure extending along the electrode arrangement surface. The back electrode 130 in this example is divided into a plurality of portions, and the plurality of portions are arranged along the arrangement direction of the power transmitting electrode group 120 . Each part of the back electrode 130 is arranged so as to cover the gap between two adjacent power transmission electrodes in the power transmission electrode group 120 . In the example of FIG. 20B, the back electrode 130 is divided into a plurality of small portions arranged two-dimensionally. In the example of FIG. 20B, the plurality of portions are arranged two-dimensionally along the arrangement direction of power transmission electrode group 120 and the direction intersecting this. Also in this example, each part of the back electrode 130 is arranged so as to cover the gap between two adjacent power transmission electrodes in the power transmission electrode group 120 . In this manner, various modifications are possible for the arrangement of the back electrode 130 .

In the above description, the configuration of the power transmission device 100 side is mainly illustrated, but the configuration of each of the modifications described above can be similarly applied to the configuration of the power reception device 200 side.

Although each electrode has a structure extending in parallel in the same direction in the above embodiments, such a structure may not be necessary depending on the application. For example, each electrode may have a rectangular shape, such as a square. The technology of the present disclosure can be applied as long as such a plurality of rectangular electrodes are arranged in one direction. Moreover, it is not an essential requirement that the surfaces of all the electrodes be on the same plane. Furthermore, the surface of each electrode does not need to have a completely planar shape, and may have, for example, a curved shape or a shape including unevenness. Also, each electrode may be inclined with respect to the road surface.

In the above explanation, the explanation given with respect to the power transmitting electrode unit can also be applied to the power receiving electrode unit as it is unless there is a contradiction. Similarly, the description given for the power receiving electrode unit is also applicable to the power transmitting electrode unit as is, unless inconsistent.

The wireless power transmission system according to the embodiments of the present disclosure can be used as a system for transporting articles within a factory, as described above. The moving body 10 has a carrier on which articles are loaded, and functions as a cart that autonomously moves within the factory and conveys articles to required locations. However, the wireless power transmission system and mobile object according to the present disclosure are not limited to such uses, and can be used for various other uses. For example, the moving body is not limited to AGVs, but may be other industrial machines, service robots, electric vehicles, forklifts, multicopters (drones), elevators, and the like. The wireless power transmission system can be used not only in factories but also in shops, hospitals, homes, roads, runways, and other places.

The technology of the present disclosure can be used for any device driven by electric power. For example, it can be used in mobile objects such as electric vehicles (EV), automated guided vehicles (AGV) used in factories, or unmanned aerial vehicles (UAV).

REFERENCE SIGNS LIST 10 moving body 30 floor surface 100 power transmission device 110 power transmission circuit 120a, 120b power transmission electrode 130 back electrode 140 side electrode 150 power transmission electrode sheet 160 power transmission control circuit 170 power conversion circuit 180 matching circuit 200 power receiving device 210 power receiving circuit 220a, 220b power receiving electrode 230 Back electrode 240 Side electrode 250 Power receiving electrode sheet 270 Power conversion circuit 280 Matching circuit 290 Charge/discharge control circuit 310 Power source 320 Load 330 Power storage device 400 Support base 420 Electric field measuring device

Claims (14)

A power transmission device used in an electric field coupling type wireless power transmission system,
a plurality of first power transmission electrodes and a plurality of second power transmission electrodes alternately arranged in a first direction along the electrode arrangement surface;
A power transmission circuit that includes a first terminal connected to the plurality of first power transmission electrodes and a second terminal connected to the plurality of second power transmission electrodes, and outputs AC power from the first terminal and the second terminal. When,
The plurality of first power transmission electrodes and the plurality of second power transmission electrodes are arranged on the rear side of the plurality of power transmission electrodes with a gap therebetween, and have a potential between the potential of the first terminal and the potential of the second terminal in the power transmission circuit. a back electrode connected to the point;
The potential of the first terminal and the second terminal in the power transmission circuit are arranged in the first direction with a gap from at least one of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. one or more side electrodes connected to a point bearing a potential between the potential of
with
the side electrode is connected to the back electrode;
transmission device. A power transmission device used in an electric field coupling type wireless power transmission system,
a plurality of first power transmission electrodes and a plurality of second power transmission electrodes alternately arranged in a first direction along the electrode arrangement surface;
a back electrode arranged with a gap on the back side of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes;
a conductive housing that houses the plurality of first power transmission electrodes, the plurality of second power transmission electrodes, and the back electrode, the housing being connected to the back electrode;
one or more side electrodes arranged with a gap in the first direction from at least one of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes and connected to the housing;
with
the side electrode is connected to the back electrode;
transmission device. The power transmission device according to claim 1 or 2 , wherein the side electrodes are positioned on both sides of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. The plurality of first power transmission electrodes and the plurality of second power transmission electrodes are arranged on the same plane,
The power transmitting device according to any one of claims 1 to 3 , wherein the side electrode includes a portion protruding from the plane in a direction perpendicular to the plane. A power transmission device used in an electric field coupling type wireless power transmission system,
a plurality of first power transmission electrodes and a plurality of second power transmission electrodes alternately arranged in a first direction along the electrode arrangement surface;
A power transmission circuit that includes a first terminal connected to the plurality of first power transmission electrodes and a second terminal connected to the plurality of second power transmission electrodes, and outputs AC power from the first terminal and the second terminal. When,
The plurality of first power transmission electrodes and the plurality of second power transmission electrodes are arranged on the rear side of the plurality of power transmission electrodes with a gap therebetween, and have a potential between the potential of the first terminal and the potential of the second terminal in the power transmission circuit. a back electrode connected to the point;
with
The power transmission device, wherein the back electrode is connected to a location in the power transmission circuit where the potential fluctuates with an amplitude less than 10% of the amplitude of the potential fluctuation of the first terminal and the second terminal. A power transmission device used in an electric field coupling type wireless power transmission system,
a plurality of first power transmission electrodes and a plurality of second power transmission electrodes alternately arranged in a first direction along the electrode arrangement surface;
A power transmission circuit that includes a first terminal connected to the plurality of first power transmission electrodes and a second terminal connected to the plurality of second power transmission electrodes, and outputs AC power from the first terminal and the second terminal. When,
The plurality of first power transmission electrodes and the plurality of second power transmission electrodes are arranged on the rear side of the plurality of power transmission electrodes with a gap therebetween, and have a potential between the potential of the first terminal and the potential of the second terminal in the power transmission circuit. a back electrode connected to the point;
The potential of the first terminal and the second terminal in the power transmission circuit are arranged in the first direction with a gap from at least one of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. one or more side electrodes connected to a point bearing a potential between the potential of
with
The power transmission device, wherein the back electrode is connected to a location in the power transmission circuit where the potential fluctuates with an amplitude less than 10% of the amplitude of the potential fluctuation of the first terminal and the second terminal. A power transmission device used in an electric field coupling type wireless power transmission system,
a plurality of first power transmission electrodes and a plurality of second power transmission electrodes alternately arranged in a first direction along the electrode arrangement surface;
A power transmission circuit that includes a first terminal connected to the plurality of first power transmission electrodes and a second terminal connected to the plurality of second power transmission electrodes, and outputs AC power from the first terminal and the second terminal. When,
The plurality of first power transmission electrodes and the plurality of second power transmission electrodes are arranged on the rear side of the plurality of power transmission electrodes with a gap therebetween, and have a potential between the potential of the first terminal and the potential of the second terminal in the power transmission circuit. a back electrode connected to the point;
with
The power transmission circuit includes a matching circuit including the first terminal and the second terminal,
The matching circuit further comprises:
a first inductor connected to the first terminal;
a second inductor connected to the second terminal;
a first capacitor and a second capacitor connected between a wiring between the first terminal and the first inductor and a wiring between the second terminal and the second inductor;
including
the back electrode is connected to a point between the first capacitor and the second capacitor ;
transmission device. A power transmission device used in an electric field coupling type wireless power transmission system,
a plurality of first power transmission electrodes and a plurality of second power transmission electrodes alternately arranged in a first direction along the electrode arrangement surface;
A power transmission circuit that includes a first terminal connected to the plurality of first power transmission electrodes and a second terminal connected to the plurality of second power transmission electrodes, and outputs AC power from the first terminal and the second terminal. When,
The plurality of first power transmission electrodes and the plurality of second power transmission electrodes are arranged on the rear side of the plurality of power transmission electrodes with a gap therebetween, and have a potential between the potential of the first terminal and the potential of the second terminal in the power transmission circuit. a back electrode connected to the point;
The potential of the first terminal and the second terminal in the power transmission circuit are arranged in the first direction with a gap from at least one of the plurality of first power transmission electrodes and the plurality of second power transmission electrodes. one or more side electrodes connected to a point bearing a potential between the potential of
with
The power transmission circuit includes a matching circuit including the first terminal and the second terminal,
The matching circuit further comprises:
a first inductor connected to the first terminal;
a second inductor connected to the second terminal;
a first capacitor and a second capacitor connected between a wiring between the first terminal and the first inductor and a wiring between the second terminal and the second inductor;
including
the back electrode is connected to a point between the first capacitor and the second capacitor;
transmission device. A power receiving device used in an electric field coupling type wireless power transmission system,
a plurality of first power receiving electrodes and a plurality of second power receiving electrodes alternately arranged in a first direction along the electrode arrangement surface;
A first terminal connected to the plurality of first power receiving electrodes and a second terminal connected to the plurality of second power receiving electrodes are provided, and AC power input from the first terminal and the second terminal is supplied to the other. a power receiving circuit that converts and outputs the power of
The plurality of first power receiving electrodes and the plurality of second power receiving electrodes are arranged on the rear side with a gap therebetween, and have a potential between the potential of the first terminal and the potential of the second terminal in the power receiving circuit. a back electrode connected to the point;
The potential of the first terminal and the second terminal in the power receiving circuit are arranged with a gap in the first direction from at least one of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes. one or more side electrodes connected to a point bearing a potential between the potential of
with
the side electrode is connected to the back electrode;
Powered device. A power receiving device used in an electric field coupling type wireless power transmission system,
a plurality of first power receiving electrodes and a plurality of second power receiving electrodes alternately arranged in a first direction along the electrode arrangement surface;
a back electrode arranged with a gap on the back side of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes;
a conductive housing that houses the plurality of first power receiving electrodes, the plurality of second power receiving electrodes, and the back electrode, the housing being connected to the back electrode;
one or more side electrodes arranged with a gap in the first direction from at least one of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes and connected to the housing;
with
the side electrode is connected to the back electrode;
Powered device. The power receiving device according to claim 9 or 10 , wherein the side electrodes are positioned on both sides of the plurality of first power receiving electrodes and the plurality of second power receiving electrodes. The plurality of first power receiving electrodes and the plurality of second power receiving electrodes are arranged on the same plane,
The power receiving device according to any one of claims 9 to 11 , wherein the side electrode includes a portion protruding from the plane in a direction perpendicular to the plane. a power transmission device according to any one of claims 1 to 8 ;
a power receiving device that wirelessly receives power from the power transmitting device;
A wireless electrode transmission system comprising: a power transmission device that wirelessly transmits power;
The power receiving device according to any one of claims 9 to 12 , wherein the power receiving device wirelessly receives power from the power transmitting device;
A wireless electrode transmission system comprising:

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