Power transmission equipment and contactless power supply system

Abstract

To provide a power transmission device and a contactless power supply system capable of transmitting power over a wide range to a power receiving device while suppressing the generation of voltage standing waves with a simple configuration.SOLUTION: A power transmission electrode portion 40 includes a first power transmission electrode 11 and a second power transmission electrode 12 formed in different layers, which are alternately connected in series, and further includes a phase advancing portion 50 that advances the phase of the high frequency power supplied from a high frequency power supply portion 14 between the adjacent first power transmission electrode 11 and the second power transmission electrode 12 that are connected in series. The phase advancing portion 50 includes a capacitor 51 connected in series between the first power transmission electrode 11 and the second power transmission electrode 12, and the capacitor 51 is formed by capacitive coupling obtained from the overlap between the first power transmission electrode 11 and the adjacent second power transmission electrode 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power transmission device that transmits power to a power receiving device equipped with power receiving electrodes that receive power and supplies the received power to a load, using an electric field coupling method in a non-contact manner, and to a non-contact power supply system equipped with the power transmission device. [Background technology]

[0002] In recent years, electric vehicles and autonomous, unmanned electric vehicles have attracted attention, and various research and development efforts are underway. However, challenges remain in the widespread adoption of such electric vehicles, including the cost and weight of batteries, the length of charging time, the difficulty of recycling, and the increase in labor costs. One method being explored to address these challenges is the development of unmanned and contactless power supply technology.

[0003] One such contactless power supply method is the electric field coupling method. In the electric field coupling method, power is transmitted without contact by transmitting through space as electric field energy through a capacitor formed between the transmitting electrode and the receiving electrode. The electric field coupling method has high power reception efficiency and power output, and can be implemented at low cost, making it suitable for contactless power supply where power transmission equipment is required over a wide area. Therefore, the electric field coupling method is attracting attention as the mainstream method for contactless power supply to electric vehicles and electric motor vehicles.

[0004] In this electric field coupling method, when the size of the transmitting electrode becomes large enough that it cannot be ignored relative to the wavelength of the high-frequency power, a voltage standing wave is generated at the transmitting electrode by the incident wave of high-frequency power supplied from one end of the transmitting electrode and the reflected wave reflected by the other end of the transmitting electrode. At the nodes of the standing wave, the voltage becomes small, and if the receiving electrode is located at a node, it becomes difficult to receive power. On the other hand, there is a need for a power transmission device that can transmit power over a wide range to the receiving device.

[0005] In response to such demands, an invention has been proposed in which the power transmission electrodes are divided into multiple sections and connected in series, while a left-handed circuit (phase-advancing circuit) that advances the phase of high-frequency power is interposed between each power transmission electrode (for example, Patent Documents 1 and 2).

[0006] Patent Document 1 presents a theoretical analysis and the effects of suppressing standing waves using a left-handed circuit interposed between power transmission electrodes. According to Patent Document 1, the phase delay in the reflected wave can be corrected by phase leading using the left-handed circuit, and since the incident wave and the reflected wave are in phase, the generation of voltage standing waves at the power transmission electrodes can be suppressed, and power can be transmitted to the power receiving device over a wide area.

[0007] In this Patent Document 1, a symmetrical CLC circuit is presented as a left-handed circuit, in which, for example, two capacitors are directly connected and an inductor is connected in parallel between the two capacitors.

[0008] Furthermore, Patent Document 2 shows a specific structure for implementing the left-handed circuit presented in Patent Document 1 onto the power transmission electrode. Patent Document 2 uses a substrate loaded with multiple capacitors used as capacitors constituting the left-handed circuit. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2014-227025 [Patent Document 2] Japanese Patent Publication No. 2019-68581 [Overview of the project] [Problems that the invention aims to solve]

[0010] However, in the structure described in Patent Document 2, increasing the number of transmission electrodes connected in cascading order to transmit power over a wide area to the power receiving device increases the number of left-handed circuits required, which in turn increases the number of circuit boards loaded with multiple capacitors. Therefore, there were problems such as increased component costs and increased difficulty in implementation.

[0011] The present invention was made to solve the above-mentioned problems, and aims to provide a power transmission device and a contactless power supply system that can transmit power over a wide area to a power receiving device while suppressing the generation of voltage standing waves with a simple configuration. [Means for solving the problem]

[0012] To achieve this objective, a first aspect of the power transmission device of the present invention transmits power to a power receiving device equipped with a power receiving electrode that receives power and supplies the received power to a load, using an electric field coupling method in a non-contact manner, comprising: a power transmission electrode section configured by connecting a plurality of power transmission electrodes in cascaded order to transmit power to the power receiving electrode; and a high-frequency power supply section that supplies high-frequency power to the power transmission electrode section, wherein the power transmission electrode section comprises a plurality of power transmission electrode forming layers on which the power transmission electrodes are formed, and a phase advance section for advancing the phase of the supplied high-frequency power, at least a portion of the space between adjacent power transmission electrodes connected in cascaded order, the phase advance section comprising a capacitor connected in series with the power transmission electrode, the capacitor being formed by capacitive coupling obtained from the overlap of adjacent power transmission electrodes formed on different power transmission electrode forming layers.

[0013] A second aspect of the power transmission device of the present invention is the power transmission device of the first aspect, wherein the power transmission electrode section comprises a pair of power transmission electrodes forming a set of power transmission electrode pairs, and power supplied from the high-frequency power supply section is transmitted to the power transmission electrode pair, and one power transmission electrode of the power transmission electrode pair is connected in cascaded order to one power transmission electrode of an adjacent power transmission electrode pair, and the other power transmission electrode is connected in cascaded order to the other power transmission electrode of the adjacent power transmission electrode pair, thereby connecting a plurality of power transmission electrode pairs in cascaded order, and the phase advance section is provided in at least a portion of the space between adjacent power transmission electrode pairs that are connected in cascaded order.

[0014] A third aspect of the power transmission device of the present invention is the power transmission device of the second aspect, wherein the phase advancement unit comprises an inductor for advancing the phase of the high-frequency power in cooperation with the capacitor, and the inductor is formed between a pair of power transmission electrodes provided on a predetermined pair of power transmission electrodes.

[0015] A fourth aspect of the power transmission device of the present invention is the power transmission device of the third aspect, wherein the inductor is composed of a single coil, one end of which is connected to one of the pair of power transmission electrodes and the other end of which is connected to the other of the pair of power transmission electrodes.

[0016] A fifth aspect of the power transmission device of the present invention is a power transmission device of the third aspect, further comprising a ground plate maintained at a reference potential, wherein the inductor comprises a first coil, one end of which is connected to one of the pair of power transmission electrodes and the other end of which is connected to the ground plate, and a second coil, one end of which is connected to the other of the pair of power transmission electrodes and the other end of which is connected to the ground plate.

[0017] A sixth aspect of the power transmission device of the present invention is the power transmission device of the fifth aspect, wherein the ground plate is formed on the side opposite to the side facing the receiving electrode with respect to the power transmission electrode forming layer, and includes a region that overlaps with the power transmission electrode when viewed from the receiving electrode side.

[0018] The seventh aspect of the power transmission device according to the present invention is that in the power transmission device of any one of the third to sixth aspects, the inductor is provided only for the power transmission electrode pair that is closest and / or farthest from the high-frequency power supply unit as the predetermined power transmission electrode pair.

[0019] The eighth aspect of the power transmission device according to the present invention is that in the power transmission device of any one of the third to seventh aspects, the inductor is constituted by a printed pattern coil formed by a pattern printed on a printed circuit board.

[0020] The ninth aspect of the non-contact power supply system according to the present invention is for supplying power to a load in a non-contact manner, and includes any one of the power transmission devices of the first to eighth aspects, and a power receiving electrode that receives power transmitted from the power transmission electrodes of the power transmission device in a non-contact manner by an electric field coupling method, and a power receiving device that supplies the received power to the load.

Advantages of the Invention

[0021] According to the first aspect of the power transmission device of the present invention, high-frequency power is supplied from the high-frequency power supply unit to the power transmission electrode unit, and power is transmitted from the power transmission electrode unit to the power receiving electrode of the power receiving device in a non-contact manner by an electric field coupling method. This power transmission electrode unit is configured by a plurality of power transmission electrodes connected in series, and a phase advancing unit for advancing the phase of the supplied high-frequency power is provided at least partially between adjacent power transmission electrodes connected in series. By this phase advancing unit, the generation of voltage standing waves in the power transmission electrode unit is suppressed, and power can be transmitted over a wide range to the power receiving device. Further, the power transmission electrode unit is provided with a plurality of power transmission electrode formation layers on which power transmission electrodes are formed, and a capacitor connected in series with the power transmission electrode constituting the phase advancing unit is formed by capacitive coupling obtained from the overlap of adjacent power transmission electrodes formed in different power transmission electrode formation layers. Thus, the capacitor of the phase advancing unit can be realized simply by providing an overlap of adjacent power transmission electrodes formed in different power transmission electrode formation layers. Therefore, this power transmission device has the effect that it can suppress the generation of voltage standing waves with a simple configuration and transmit power over a wide range to the power receiving device.

[0022] According to a second embodiment of the power transmission device of the present invention, in addition to the effects of the first embodiment, the following effects are achieved. Specifically, the power transmission electrode section is composed of a pair of power transmission electrodes, and power supplied from the high-frequency power supply section is transmitted to this power transmission electrode pair. One power transmission electrode of the power transmission electrode pair is connected in cascaded order to one power transmission electrode of an adjacent power transmission electrode pair, and the other power transmission electrode is connected in cascaded order to the other power transmission electrode of the adjacent power transmission electrode pair, thereby connecting multiple power transmission electrode pairs in cascaded order. The phase advancement section is provided in at least a portion of the space between adjacent power transmission electrode pairs that are connected in cascaded order, and the capacitor of this phase advancement section is realized simply by providing an overlap of adjacent power transmission electrodes formed on different power transmission electrode forming layers. Therefore, even if the power transmission electrode section is composed of a pair of power transmission electrode pairs connected in cascaded order, it is possible to transmit power to a power receiving device over a wide area while suppressing the generation of voltage standing waves with a simple configuration.

[0023] According to a third aspect of the power transmission device of the present invention, in addition to the effects of the second aspect, the following effects are achieved. Specifically, the phase advancement section advances the phase of high-frequency power by means of an inductor in cooperation with a capacitor. This inductor is formed between a pair of power transmission electrodes provided on a predetermined power transmission electrode pair. As a result, the generation of voltage standing waves can be suppressed with a simple configuration by using a capacitor realized simply by providing an overlap between adjacent power transmission electrodes formed on different power transmission electrode forming layers, and this inductor.

[0024] According to a fourth aspect of the power transmission device of the present invention, in addition to the effects of the third aspect, the following effects are achieved. That is, the inductor of the phase-advancing section is composed of a single coil, one end of which is connected to one of the pair of power transmission electrodes and the other end of which is connected to the other of the pair of power transmission electrodes, thus reducing the number of parts.

[0025] According to a fifth aspect of the power transmission device of the present invention, in addition to the effects of the third aspect, the following effects are achieved. Specifically, a ground plate maintained at a reference potential is provided, and the inductor of the phase-advancing section is composed of a first coil, one end of which is connected to one of a pair of power transmission electrodes and the other end of which is connected to the ground plate, and a second coil, one end of which is connected to the other of the pair of power transmission electrodes and the other end of which is connected to the ground plate. As a result, the inductor between the power transmission electrodes is formed by connecting the first coil and the second coil between the pair of power transmission electrodes via the ground plate, which has the effect of making it easier to mount the inductor.

[0026] According to a sixth aspect of the power transmission device of the present invention, in addition to the effects of the fifth aspect, the following effects are achieved. That is, the ground plate is formed on the side opposite to the side facing the receiving electrode with respect to the power transmission electrode forming layer, and includes a region that overlaps with the power transmission electrode when viewed from the receiving electrode side. Therefore, the other end of the first coil, one end of which is connected to one of the pair of power transmission electrodes, can be easily connected to the ground plate, and the other end of the second coil, one end of which is connected to the other of the pair of power transmission electrodes, can be easily connected to the ground plate. Thus, there is an effect of increasing the degree of freedom in mounting the inductor.

[0027] According to the seventh aspect of the power transmission device of the present invention, in addition to the effects of any of the third to sixth aspects, the following effect is achieved. That is, since the inductor is provided only for the power transmission electrode pair closest to and / or furthest from the high-frequency power supply unit as a predetermined power transmission electrode pair, the number of parts can be reduced.

[0028] According to the eighth aspect of the power transmission device of the present invention, in addition to the effects of any of the third to seventh aspects, the following effects are achieved. That is, since the inductor is composed of a printed pattern coil formed by a pattern printed on a printed circuit board, the inductor is planar. Therefore, the volume required for mounting the inductor can be reduced, which has the effect of making the mounting of the inductor easier.

[0029] According to the ninth aspect of the contactless power supply system of the present invention, a power transmission device according to any of the first to eighth aspects is provided, and the power transmitted from the power transmission electrode of the power transmission device is received by the power receiving electrode of the power receiving device in a contactless manner by electric field coupling. The power received by the power receiving device is then supplied to the load. This makes it possible to achieve the same effects as the corresponding power transmission devices of the first to eighth aspects. [Brief explanation of the drawing]

[0030] [Figure 1] (a) is a schematic front view of a power transmission device and a contactless power supply system according to the first embodiment of the present invention, and (b) is a schematic plan view of the same power transmission device and contactless power supply system. [Figure 2] (a) is a schematic diagram of the phase-advancing section provided in the power transmission device, (b) is an equivalent circuit diagram of the phase-advancing section, and (c) is an equivalent circuit diagram of the power transmission device. [Figure 3] (a) is a schematic diagram showing one example of the construction of a capacitor in the co-phase-forward section, and (b) is a schematic diagram showing another example of the construction of the same capacitor. [Figure 4] (a) is a schematic perspective view of a power transmission device according to a second embodiment of the present invention, and (b) is a schematic perspective view showing another example of the same power transmission device. [Figure 5] (a) is an equivalent circuit diagram of a power transmission device according to a third embodiment of the present invention, and (b) is a schematic perspective view showing an implementation example of the power transmission device. [Figure 6] (a) is a schematic perspective view showing another implementation example of the power transmission device, and (b) is a schematic perspective view showing yet another implementation example of the power transmission device. [Figure 7] (a) is an equivalent circuit diagram of a power transmission device according to a fourth embodiment of the present invention, and (b) is a schematic perspective view showing an implementation example of the power transmission device. [Figure 8] (a) is a schematic perspective view showing another implementation example of the power transmission device, and (b) is a schematic perspective view showing yet another implementation example of the power transmission device. [Figure 9](a) is an equivalent circuit diagram of a power transmission device according to a fifth embodiment of the present invention, and (b) is a schematic perspective view showing an example of the implementation of the power transmission device. [Figure 10] (a) is a schematic perspective view showing another implementation example of the power transmission device, and (b) is a schematic perspective view showing yet another implementation example of the power transmission device. [Figure 11] (a) is a schematic plan view showing the printed pattern coils that constitute the phase advancement section 50 of the power transmission device 10, and (b) is a cross-section view of the end when cut along the cutting line XIb shown in (a). [Figure 12] (a) is a schematic diagram illustrating an example of forming a second power transmission electrode by sandwiching the first power transmission electrode, and (b) is a schematic diagram illustrating another example of forming a second power transmission electrode by sandwiching the first power transmission electrode. [Modes for carrying out the invention]

[0031] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The embodiments described below are all preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples and are not intended to limit the present invention. Accordingly, among the components in the following embodiments, those not described in the independent claims representing the highest-level concept of the present invention will be described as optional components. Furthermore, in each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0032] (First Embodiment) First, the schematic configuration of the power transmission device 10 and contactless power supply system 1 according to the first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1(a) is a schematic front view of the power transmission device 10 and contactless power supply system 1, and Figure 1(b) is a schematic plan view of the power transmission device 10 and contactless power supply system 1. However, in Figure 1(b), the travel path G is omitted.

[0033] Furthermore, Figure 2(a) is a schematic diagram of the phase-advancing unit 50 provided in the power transmission device 10, Figure 2(b) is an equivalent circuit diagram of the phase-advancing unit 50, and Figure 2(c) is an equivalent circuit diagram of the power transmission device 10. Also, Figure 3(a) is a schematic diagram showing one example of the construction of the capacitor 51 of the phase-advancing unit 50, and Figure 3(b) is a schematic diagram showing another example of the construction of the capacitor 51.

[0034] The contactless power supply system 1 is a system that supplies power to a load wirelessly (without contact). In the example shown in Figure 1, the contactless power supply system 1 uses a battery 31 mounted on a mobile body 30 traveling on a road G as the load, and supplies power to the battery 31 wirelessly. It consists of a power transmission device 10 fixedly installed on the road G and a power receiving device 20 provided on the mobile body 30.

[0035] The mobile unit 30 is exemplified by electric vehicles such as electric cars and automated guided vehicles (AGVs) that operate automatically without a driver. In addition to the power receiving device 20 and battery 31, it has drive wheels 32 and driven wheels 33. The mobile unit 30 receives power transmitted wirelessly from the power transmission device 10 at the power receiving device 20 and charges the battery 31 by supplying the received power to the battery 31. The mobile unit 30 drives the drive wheels 32 using the power from the charged battery 31 and travels along the road G.

[0036] Furthermore, the load that receives power via the contactless power supply system 1 may be a battery 31 or other device that operates using the supplied power (for example, a motor). Also, the load does not necessarily have to be mounted on a self-propelled device such as the mobile body 30; the power receiving device 20 and the load may be mounted on a non-self-propelled device, or the power receiving device 20 may be attached to the load itself.

[0037] The power transmission device 10 is a device that transmits (transmits) power to the power receiving device 20 in a non-contact manner using an electric field coupling method, and comprises at least a high-frequency power supply unit 14 and a power transmission electrode unit 40.

[0038] The high-frequency power supply unit 14 is a high-frequency inverter that generates high-frequency power from DC power or commercial power, and is fixed to or embedded in the travel path G. The high-frequency power generated by the high-frequency power supply unit 14 is supplied to the power transmission electrode unit 40.

[0039] The power transmission electrode section 40 includes at least a first power transmission electrode forming layer 11a on which a plurality of first power transmission electrodes 11 are formed, a second power transmission electrode forming layer 12a on which a plurality of second power transmission electrodes 12 are formed, and a phase advance section 50 (see Figure 2(a)).

[0040] The first power transmission electrode 11 and the second power transmission electrode 12 correspond to the power transmission electrodes of the present invention and are each composed of flat conductors embedded directly beneath the road surface of the travel path G. The size (length) of one first power transmission electrode 11 is set to be such that the wavelength of high-frequency power is negligible, and the size (length) of one second power transmission electrode 12 is set to be shorter than that of the first power transmission electrode 11. However, one second power transmission electrode 12 may be set to be longer than that of the first power transmission electrode 11.

[0041] The first power transmission electrode forming layer 11a, on which multiple first power transmission electrodes 11 are formed, is located directly beneath the road surface of the road G, while the second power transmission electrode forming layer 12a, on which multiple second power transmission electrodes 12 are formed, is located at a deeper position than the first power transmission electrode forming layer 11a. In other words, the first power transmission electrode forming layer 11a and the second power transmission electrode forming layer 12a are located at different positions (depths). These first power transmission electrode forming layer 11a and the second power transmission electrode forming layer 12a correspond to the power transmission electrode forming layers of the present invention.

[0042] In this embodiment, the case in which the second power transmission electrode forming layer 12a is provided at a deeper position than the first power transmission electrode forming layer 11a is described. However, the first power transmission electrode forming layer 11a and the second power transmission electrode forming layer 12a do not need to be provided at different positions (depths), and the second power transmission electrode forming layer 12a may be provided at a shallower position than the first power transmission electrode forming layer 11a.

[0043] As shown in Figure 1(b), each of the multiple first power transmission electrodes 11 formed in the first power transmission electrode forming layer 11a has a pair of first power transmission electrodes 11, and these pairs of first power transmission electrodes 11 constitute a set of first power transmission electrode pairs 11b. Similarly, each of the multiple second power transmission electrodes 12 formed in the second power transmission electrode forming layer 12a has a pair of second power transmission electrodes 12, and these pairs of second power transmission electrodes 12 constitute a set of second power transmission electrode pairs 12b. The power transmission electrode section 40 is constructed by connecting these first power transmission electrode pairs 11b and second power transmission electrode pairs 12b alternately in cascaded order.

[0044] Specifically, in any first power transmission electrode pair 11b, one of the first power transmission electrodes 11 constituting that first power transmission electrode pair 11b is connected in cascaded form to one of the second power transmission electrodes 12 constituting the adjacent second power transmission electrode pair 12b, and the other first power transmission electrode 11 constituting that first power transmission electrode pair 11b is connected in cascaded form to the other second power transmission electrode 12 constituting the adjacent second power transmission electrode pair 12b. In this way, the power transmission electrode section 40 is such that the transmission line through which high-frequency power is transmitted is divided into a plurality of first power transmission electrodes 11 and a plurality of second power transmission electrodes 12.

[0045] This cascaded connection is formed with respect to both the second power transmission electrode pair 12b adjacent to the first power transmission electrode pair 11b on the upstream side (high-frequency power supply unit 14 side) and the second power transmission electrode pair 12b adjacent to the downstream side (opposite side from the high-frequency power supply unit 14).

[0046] In the power transmission electrode section 40, a second power transmission electrode pair 12b is installed on the side closest to the high-frequency power supply unit 14 (nearest side) and the side furthest from it (farthest side). The high-frequency power supply unit 14 is connected via a matching circuit (not shown) to one end of the second power transmission electrode 12 of the second power transmission electrode pair 12b located on the nearest side of the high-frequency power supply unit 14, and the other end is connected to the other second power transmission electrode 12 of the second power transmission electrode pair 12b. As a result, the high-frequency power output from the high-frequency power supply unit 14 is supplied to the power transmission electrode section 40.

[0047] As described above, the first power transmission electrode 11 and the second power transmission electrode 12, which are connected in cascaded order, are formed in the first power transmission electrode forming layer 11a or the second power transmission electrode forming layer 12a, which are located at different positions (depths). These first power transmission electrode 11 and the second power transmission electrode 12, which are formed at different positions (depths), are arranged so that an overlapping region is formed when viewed from the direction of arrow U in Figure 1(a).

[0048] Capacitive coupling is achieved by the overlap of adjacent first and second power transmission electrodes 11 and 12 formed in the first and second power transmission electrode forming layers 11a and 12a, which are located at different positions (depths), and a capacitor 51 with capacitance C is formed in each overlapping region, as shown in Figure 2(a).

[0049] This capacitor 51 has a relative permittivity ε, as shown in Figure 3(a), for example. r The device is obtained by sandwiching an insulating layer 15 made of an insulator with a thickness d between the insulating layer 15, forming a second power transmission electrode 12 below the insulating layer 15, and forming a first power transmission electrode 11 above the insulating layer 15 such that it overlaps with the second power transmission electrode 12 by a predetermined overlap area S when viewed from the direction of arrow U. The thickness d of the insulating layer 15 is equal to the distance d between the first power transmission electrode 11 and the second power transmission electrode 12.

[0050] Alternatively, as shown in Figure 3(b), the capacitor 51 can also be obtained by creating an overlap of a predetermined overlap area S between the adjacent first power transmission electrode 11 and second power transmission electrode 12, and then inserting a spacer 16 of length d made of an insulator between them, and fixing the first power transmission electrode 11, the spacer 16, and the second power transmission electrode 12 with an insulating bolt 17 and an insulating nut 18. The length d of the spacer 16 is equal to the distance d between the first power transmission electrode 11 and the second power transmission electrode 12. In this case, the insulating layer between the first power transmission electrode 11 and the second power transmission electrode 12 is air. The relative permittivity of air is ε. r It is approximately 1.

[0051] On the other hand, as shown in Figures 1(a), (b) and 2(a), in the power transmission electrode section 40, a coil 13 with inductance L is provided between the pair of second power transmission electrodes 12 in each second power transmission electrode pair 12b. However, in the second power transmission electrode pairs 12b provided on the nearest and furthest sides of the high-frequency power supply section 14, a coil 13 with inductance 2L is provided between the pair of second power transmission electrodes 12. The coil 13 is either air-cored or has a three-dimensional shape using a ferrite core. This coil 13 corresponds to the inductor of the present invention.

[0052] Thus, for adjacent first power transmission electrode pairs 11b and second power transmission electrode pairs 12b, two capacitors 51 with capacitance C formed between one first power transmission electrode 11 and one second power transmission electrode 12 are connected in series between the first first power transmission electrode 11, and two capacitors 51 with capacitance C formed between the other first power transmission electrode 11 and one second power transmission electrode 12 are connected in series between the other first power transmission electrode 11. In addition, a coil 13 with inductance L between the pair of second power transmission electrodes 12 is connected in parallel between one first power transmission electrode 11 and the other first power transmission electrode 11.

[0053] With the configuration of the capacitor 51 and coil 13 as described above, a symmetrical CLC circuit as shown in Figure 2(b) is formed between the first power transmission electrode pair 11b adjacent to the second power transmission electrode pair 12b on the upstream side (high-frequency power supply unit 14 side) and the first power transmission electrode pair 11b adjacent to the downstream side (opposite side of the high-frequency power supply unit 14).

[0054] That is, as shown in Figure 2(c), the power transmission electrode section 40 is represented by an equivalent circuit in which a symmetrical CLC circuit, as shown in Figure 2(b), is connected in cascaded order between the adjacent first power transmission electrode pair 11b and the first power transmission electrode pair 11b via the second power transmission electrode pair 12b. This symmetrical CLC circuit becomes a phase-advancing section 50 in which the capacitor 51 and the coil 13 (inductor) work together to advance the phase of the high-frequency power, as described in Patent Documents 1 and 2.

[0055] Furthermore, in the power transmission electrode section 40, on the nearest and furthest sides of the high-frequency power supply section 14, a capacitor 51 with capacitance C formed between one of the paired first power transmission electrodes 11 and second power transmission electrode 12 is connected in series with the first first power transmission electrode 11, and a capacitor 51 with capacitance C formed between the other first power transmission electrode 11 and second power transmission electrode 12 is connected in series with the other first power transmission electrode 11. In addition, a coil 13 (inductor) with inductance 2L between the paired second power transmission electrodes 12 is connected in parallel between one first power transmission electrode 11 and the other first power transmission electrode 11.

[0056] With the above configuration, in the power transmission electrode section 40, circuits 50a and 50b, as shown in Figure 2(c), are formed in cascaded connection to the nearest and furthest sides of the high-frequency power supply section 14. When combined, circuits 50a and 50b are equivalent to a single symmetric CLC circuit, and together circuits 50a and 50b form a single phase advance section 50.

[0057] Here, the capacitance C of the capacitor 51 of the phase advance unit 50 and the inductance L (and 2L) of the coil 13 are appropriately determined based on the size (length) of the first power transmission electrode 11 and the size (length) of the second power transmission electrode 12, etc. The capacitance C of the capacitor 51 is expressed by the following equation (1). Here, ε0 is the permittivity of vacuum.

[0058] C=ε r ε0S / d (1) The power transmission electrode section 40 has a distance d between the first power transmission electrode 11 and the second power transmission electrode 12, an overlapping area S, and a relative permittivity ε. r By changing at least one of these, a capacitor 51 with the desired capacitance C can be formed.

[0059] As shown in Figures 1(a) and (b), the power receiving device 20 includes at least a pair of receiving electrodes 21 that receive power transmitted from the first power transmitting electrode 11 and the second power transmitting electrode 12 in a non-contact manner using an electric field coupling method.

[0060] Specifically, each pair of receiving electrodes 21 is composed of a flat conductor. When the mobile body 30 is traveling along the travel path G, one receiving electrode 21 is positioned to overlap with one of the pair of first transmitting electrodes 11 or one of the pair of second transmitting electrodes 12, as viewed from the direction of arrow U, and the other receiving electrode 21 is positioned to overlap with the other of the pair of first transmitting electrodes 11 or the other of the pair of second transmitting electrodes 12.

[0061] The power received by the receiving electrode 21 is supplied to the battery 31 via a matching circuit and a rectifier circuit (not shown).

[0062] The power transmission device 10 and the contactless power supply system 1 configured as described above operate as follows.

[0063] The high-frequency power output from the high-frequency power supply unit 14 is supplied to the power transmission electrode unit 40. When the mobile body 30 travels along the travel path G and the receiving electrode 21 of the power receiving device 20 provided on the mobile body 30 faces the first power transmission electrode 11 or the second power transmission electrode 12 of the power transmission electrode unit 40, a capacitor is formed between the receiving electrode 21 and the first power transmission electrode 11, or between the receiving electrode 21 and the second power transmission electrode 12. The power transmitted to the first power transmission electrode 11 and the second power transmission electrode 12 is transmitted to the receiving electrode 21 non-contact by an electric field coupling method, where the power is transmitted through space as electric field energy.

[0064] The power received by the receiving electrode 21 is supplied to the battery 31, and the battery 31 is charged. The mobile body 30 travels along the road G by using the power from the charged battery 31 to drive the drive wheels 32.

[0065] Here, in the power transmission electrode section 40, the transmission line is divided into a plurality of first power transmission electrodes 11 and a plurality of second power transmission electrodes 12, and the first power transmission electrodes 11 and the second power transmission electrodes 12 are connected alternately in cascaded order. Furthermore, in the power transmission electrode section 40, a phase advance section 50 is formed between adjacent cascaded first power transmission electrodes 11 by a capacitor 51 formed by capacitive coupling obtained from the overlap of adjacent first power transmission electrodes 11 and second power transmission electrodes 12, and a coil 13, which is an inductor, provided in parallel between a pair of second power transmission electrodes 12, and the two are connected in cascaded order.

[0066] When high-frequency power is transmitted from a single high-frequency power supply unit 14 to a transmission line over a long distance, the phase of the high-frequency power lags behind. In addition, reflected waves reflected from the far end of the transmission line are also present, and voltage standing waves are generated due to the relative phase relationship between the forward wave and the reflected wave.

[0067] In contrast, in this first embodiment, a phase advance unit 50 is formed between adjacent first transmission electrodes 11 that are connected in cascaded order, and the phases of the high-frequency power transmitted through the first and second transmission electrodes 11 are canceled out by this phase advance unit 50. Furthermore, the size (length) of each first and second transmission electrode 11 and second transmission electrode 12 is set to a length that is negligible compared to the wavelength of the high-frequency power, so the phases of the high-frequency power within each first and second transmission electrode 11 and second transmission electrode 12 are also negligible.

[0068] Therefore, regardless of the location of the mobile body 30 on the power transmission electrode section 40, impedance mismatch can be kept to a minimum, the generation of voltage standing waves in the power transmission electrode section 40 is suppressed, and power can be transmitted to the power receiving device 20 over a wide area.

[0069] The power transmission device 10 and contactless power supply system 1 described above will produce the following effects.

[0070] (1) The power transmission electrode section 40 is provided with a first power transmission electrode forming layer 11a on which the first power transmission electrode 11 is formed, and a second power transmission electrode forming layer 12a on which the second power transmission electrode 12 is formed. Capacitance coupling obtained from the overlap of the first power transmission electrode 11 and the second power transmission electrode 12, which are adjacent to each other at different positions (depths), forms a capacitor 51 with capacitance C that constitutes the phase-advancing section 50, and connects it in series with the first power transmission electrode 11. In this way, the capacitor 51 of the phase-advancing section 50 can be realized without preparing a capacitor as a component, simply by providing an overlap of adjacent power transmission electrodes formed in different power transmission electrode forming layers. Therefore, the power transmission device 10 and the non-contact power supply system 1 can transmit power over a wide area to the power receiving device 20 while suppressing the generation of voltage standing waves with a simple configuration by dividing the transmission line of the power transmission electrode section 40 that transmits high-frequency power into a plurality of first power transmission electrodes 11 and a plurality of second power transmission electrodes 12, and connecting them in cascading order while overlapping them alternately.

[0071] (2) The power transmission electrode section 40 is composed of a pair of first power transmission electrodes 11 to form a first power transmission electrode pair 11b, and a pair of second power transmission electrodes 12 to form a second power transmission electrode pair 12b. These first power transmission electrode pairs 11b and second power transmission electrode pairs 12b are alternately connected in cascaded configuration. Specifically, one first power transmission electrode 11 of the first power transmission electrode pair 11b is connected in cascaded configuration to one second power transmission electrode 12 of the adjacent second power transmission electrode pair 12b, and the other first power transmission electrode 11 is connected in cascaded configuration to the other second power transmission electrode 12 of the adjacent second power transmission electrode pair 12b. Power supplied from the high-frequency power supply section 14 is transmitted through these alternately connected first power transmission electrode pairs 11b and second power transmission electrode pairs 12b. The phase-shifting unit 50 is provided between adjacent first power transmission electrode pairs 11b and second power transmission electrode pairs 12b that are connected in cascaded order. The capacitor 51 of this phase-shifting unit 50 is realized simply by creating an overlap between the first power transmission electrodes 11 and second power transmission electrodes 12 that are at different positions (depths). Therefore, even if the power transmission electrode unit 40 is configured such that a pair of first power transmission electrode pairs 11b, composed of a pair of first power transmission electrodes 11, and a pair of second power transmission electrode pairs 12b, composed of a pair of second power transmission electrodes 12, are alternately connected in cascaded order, it is possible to transmit power to the power receiving device 20 over a wide area while suppressing the generation of voltage standing waves with a simple configuration.

[0072] (3) The phase advancement unit 50 advances the phase of the high-frequency power through the cooperation of the capacitor 51 and the inductor coil 13. This coil 13 is formed between the pair of second transmission electrodes 12 provided on the second transmission electrode pair 12b. As a result, the capacitor 51, which is realized simply by creating an overlap between the first transmission electrode 11 and the second transmission electrode 12 at different positions (depths), and this coil 13 can suppress the generation of voltage standing waves with a simple configuration.

[0073] (4) The inductor provided in the phase advancement section 50 of (1) consists of a single coil 13, one end of which is connected to one of the pair of second power transmission electrodes 12, and the other end of which is connected to the other of the pair of second power transmission electrodes 12, thus reducing the number of parts.

[0074] (Second Embodiment) Next, with reference to Figure 4, a power transmission device 10 according to a second embodiment of the present invention will be described. Figure 4(a) is a schematic perspective view of the power transmission device 10, and Figure 4(b) is a schematic perspective view showing another example of the power transmission device 10. In Figures 4(a) and (b), the same reference numerals are used for components identical to those in the power transmission device 10 according to the first embodiment, and their explanation is omitted here. Furthermore, the contactless power supply system 1 according to the second embodiment has the same configuration as the contactless power supply system 1 according to the first embodiment, except that the power transmission device 10 of the second embodiment is used instead of the power transmission device 10 of the first embodiment, so its explanation is omitted.

[0075] In the power transmission device 10 according to the second embodiment, a ground plate 19 is provided below the first power transmission electrode 11 and the second power transmission electrode 12, with an insulating layer in between. The ground plate 19 is a flat conductor maintained at a reference potential, and is formed on the side opposite to the side where the receiving electrode 21 faces the first power transmission electrode forming layer 11a and the second power transmission electrode forming layer 12a (see Figure 1(a)), including a region that overlaps with the first power transmission electrode 11 and the second power transmission electrode 12 when viewed from the receiving electrode 21 side.

[0076] By providing the ground plate 19, it is possible to suppress the high-frequency power transmitted to the first power transmission electrode 11 and the second power transmission electrode 12 from having various effects on various objects located beneath the road surface of the travel path G, such as the ground or under the floor, and conversely, from such objects having various effects on the high-frequency power transmitted to the first power transmission electrode 11 and the second power transmission electrode 12.

[0077] Furthermore, in the power transmission device 10 according to the second embodiment, the inductor of the phase-advancing unit 50 provided on the second power transmission electrode pair 12b is formed via a ground plate 19. Specifically, the inductor is composed of a first coil 13a with an inductance of L / 2, one end of which is connected to one of the paired second power transmission electrodes 12 and the other end of which is connected to the ground plate 19, and a second coil 13b with an inductance of L / 2, one end of which is connected to the other of the paired second power transmission electrodes 12 and the other end of which is connected to the ground plate.

[0078] Specifically, the inductor of the phase-advancing unit 50 is divided into two coils, a first coil 13a and a second coil 13b, which are connected in series and mounted. The first coil 13a and the second coil 13b are three-dimensional in shape using air cores or ferrite cores. The first coil 13a and the second coil 13b connected in series act equivalently to the coil 13 with inductance L according to the first embodiment.

[0079] As shown in Figure 4(a), for all second power transmission electrode pairs 12b on which inductors are provided, the inductor may be divided into a first coil 13a and a second coil 13b for implementation.

[0080] Furthermore, for some of the second power transmission electrode pairs 12b on which inductors are provided, the inductor may be divided into a first coil 13a and a second coil 13b for some of the second power transmission electrode pairs 12b, and for the remaining second power transmission electrode pairs 12b, a single coil 13 may be used, as in the first embodiment. For example, in the example shown in Figure 4(b), a single coil 13 is implemented in the second power transmission electrode pairs 12b provided on the nearest and furthest sides of the high-frequency power supply unit 14, and the first coil 13a and the second coil 13b are implemented in the other second power transmission electrode pairs 12b to constitute the inductor of the phase-advancing unit 50.

[0081] Furthermore, the inductances of the first coil 13a and the second coil 13b do not necessarily have to be L / 2; their respective inductances may be adjusted so that their combined inductance is L.

[0082] The power transmission device 10 according to the second embodiment described above provides the following effects.

[0083] (5) A ground plate 19 is provided, which is maintained at a reference potential. The inductor of the phase advance unit 50 is composed of a first coil 13a, one end of which is connected to one of the pair of second power transmission electrodes 12 and the other end of which is connected to the ground plate 19, and a second coil 13b, one end of which is connected to the other of the pair of second power transmission electrodes 12 and the other end of which is connected to the ground plate 19. This makes the size of the first coil 13a and the second coil 13b smaller than that of the coil 13 according to the first embodiment. Furthermore, even if an insulating layer or the like exists between the first power transmission electrodes 11 and the second power transmission electrodes 12 and the ground plate 19, the first coil 13a and the second coil 13b can be easily connected between the pair of second power transmission electrodes 12 via the ground plate 19. Therefore, in addition to the miniaturization of the first coil 13a and the second coil 13b, it is possible to easily mount the inductor between the second power transmission electrodes 12.

[0084] (6) The ground plate 19 is formed on the side opposite to the side facing the receiving electrode 21 with respect to the first power transmitting electrode forming layer 11a and the second power transmitting electrode forming layer 12a, and includes a region that overlaps with the first power transmitting electrode 11 and the second power transmitting electrode 12 when viewed from the receiving electrode 21 side. Therefore, the other end of the first coil 13a, whose one end is connected to one of the paired second power transmitting electrodes 12, can be easily connected to the ground plate 19, and the other end of the second coil 13b, whose one end is connected to the other of the paired second power transmitting electrodes 12, can be easily connected to the ground plate 19. Thus, the degree of freedom in mounting the inductor can be increased.

[0085] Furthermore, the power transmission device 10 according to the second embodiment has the same configuration as the power transmission device 10 according to the first embodiment and achieves the same effects. Also, the contactless power supply system 1 equipped with the power transmission device 10 according to the second embodiment achieves the effects of the power transmission device 10.

[0086] (Third embodiment) Next, with reference to Figures 5 and 6, a power transmission device 10 according to the third embodiment of the present invention will be described. Figure 5(a) is an equivalent circuit diagram of the power transmission device 10, Figure 5(b) is a schematic perspective view showing an example of the implementation of the power transmission device 10, Figure 6(a) is a schematic perspective view showing another example of the implementation of the power transmission device 10, and Figure 6(b) is a schematic perspective view showing yet another example of the implementation of the power transmission device 10.

[0087] In Figures 5 and 6, the same reference numerals are used for components identical to those in the power transmission device 10 of the first and second embodiments, and their explanation is omitted here. Furthermore, the contactless power supply system 1 of the third embodiment has the same configuration as the contactless power supply system 1 of the first embodiment, except that the power transmission device 10 of the third embodiment is used instead of the power transmission device 10 of the first and second embodiments; therefore, its explanation is omitted.

[0088] In the third embodiment, as shown in the equivalent circuit of Figure 5(a), the inductors of the phase-advancing unit 50 that are connected in parallel to each second power-transmitting electrode pair 12b in the first or second embodiment are combined into a single inductor, and this combined inductor is provided only to the second power-transmitting electrode pair 12b located closest to the high-frequency power supply unit 14.

[0089] For example, when constructing a phase-advancing unit 50 equivalent to the power transmission device 10 according to the first embodiment shown in Figure 2(c) in the third embodiment, if we assume that in Figure 2(c), a coil 13 with inductance 2L is mounted in parallel on the nearest and furthest sides of the high-frequency power supply unit 14, and that n other coils 13 with inductance L are mounted in parallel, then in the third embodiment, it is sufficient to provide an inductor with a combined inductance L / (n+1) only on the second power transmission electrode pair 12b located on the nearest side of the high-frequency power supply unit 14.

[0090] Even if only one composite inductor is provided at the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14, the cooperation between this single inductor and the capacitors 51 formed by the overlap of the adjacent first power transmission electrode 11 and second power transmission electrode 12 allows the phase of the high-frequency power to be advanced, and as a result, the generation of voltage standing waves at the power transmission electrode unit 40 can be suppressed.

[0091] The inductor of the phase-advancing unit 50 according to this third embodiment may be implemented, for example, by connecting one coil 13 with inductance L / (n+1) between the second power transmission electrode 12 of the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14, as shown in Figure 5(b), in the same manner as in the first embodiment.

[0092] Furthermore, as shown in Figure 6(a), if a ground plate 19 similar to that of the second embodiment is provided, the first coil 13a and the second coil 13b, having an inductance of L / (2(n+1)), may be connected between the second power transmission electrode 12 of the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14 via the ground plate 19, similar to Figure 4(a) of the second embodiment. Note that as long as the combined inductance of the first coil 13a and the second coil 13b is L / (n+1), the individual inductances may be arbitrary.

[0093] Furthermore, even if a ground plate 19 is provided, it goes without saying that, as shown in Figure 6(b), it may also be implemented by connecting one coil 13 with inductance L / (n+1) between the second power transmission electrodes 12b of the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14, in the same manner as in the first embodiment.

[0094] The power transmission device 10 according to the third embodiment described above provides the following effects.

[0095] (7) Since the inductor constituting the phase advancement unit 50 is provided only for the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14, the number of components can be reduced and costs can be lowered. Furthermore, ease of implementation can be improved.

[0096] (8) By combining the inductors into one, the required inductance for that inductor can be reduced to L / (n+1). Therefore, the coil 13 or the first coil 13a and the second coil 13b required to implement that inductor can be reduced. Thus, cost reduction and ease of implementation can be improved.

[0097] Furthermore, the power transmission device 10 according to the third embodiment has the same configuration as the power transmission devices 10 according to the first and second embodiments and achieves the same effects. Also, the contactless power supply system 1 equipped with the power transmission device 10 according to the third embodiment achieves the effects of the power transmission device 10.

[0098] (Fourth Embodiment) Next, with reference to Figures 7 and 8, a power transmission device 10 according to the fourth embodiment of the present invention will be described. Figure 7(a) is an equivalent circuit diagram of the power transmission device 10, Figure 7(b) is a schematic perspective view showing an example of the implementation of the power transmission device 10, Figure 8(a) is a schematic perspective view showing another example of the implementation of the power transmission device 10, and Figure 8(b) is a schematic perspective view showing yet another example of the implementation of the power transmission device 10.

[0099] In Figures 7 and 8, the same reference numerals are used for components identical to those in the power transmission device 10 of the first to third embodiments, and their explanation is omitted here. Furthermore, the contactless power supply system 1 of the fourth embodiment is identical in configuration to the contactless power supply system 1 of the first embodiment, except that the power transmission device 10 of the fourth embodiment is used instead of the power transmission device 10 of the first to third embodiments; therefore, its explanation is omitted.

[0100] In the third embodiment, the inductors of the phase-advancing unit 50 connected in parallel to each second power-transmitting electrode pair 12b in the first or second embodiment are combined into a single inductor, and the combined inductor is provided only to the second power-transmitting electrode pair 12b closest to the high-frequency power supply unit 14. However, in the fourth embodiment, as shown in the equivalent circuit of Figure 7(a), the combined inductor with inductance L / (n+1) is provided only to the second power-transmitting electrode pair 12b furthest from the high-frequency power supply unit 14.

[0101] Even if a single composite inductor is provided only at the second power transmission electrode pair 12b located furthest from the high-frequency power supply unit 14, similar to the third embodiment, this single inductor and the capacitors 51 formed by the overlap of the adjacent first power transmission electrode 11 and second power transmission electrode 12 work together to advance the phase of the high-frequency power, thereby suppressing the generation of voltage standing waves in the power transmission electrode unit 40.

[0102] The inductor of the phase-advancing unit 50 according to this fourth embodiment may be implemented, for example, by connecting one coil 13 with inductance L / (n+1) between the second power transmission electrodes 12b of the second power transmission electrode pair 12b located on the furthest side of the high-frequency power supply unit 14, as shown in Figure 7(b), in the same manner as in the first embodiment.

[0103] Furthermore, as shown in Figure 8(a), if a ground plate 19 similar to that of the second embodiment is provided, the first coil 13a and the second coil 13b, having an inductance of L / (2(n+1)), may be connected between the second power transmission electrode 12 of the second power transmission electrode pair 12b located on the furthest side of the high-frequency power supply unit 14 via the ground plate 19, similar to Figure 4(a) of the second embodiment. Note that as long as the combined inductance of the first coil 13a and the second coil 13b is L / (n+1), the individual inductances can be any value.

[0104] Furthermore, even if a ground plate 19 is provided, as shown in Figure 8(b), it may be implemented by connecting one coil 13 with inductance L / (n+1) between the second power transmission electrodes 12b of the second power transmission electrode pair 12b located on the furthest side of the high-frequency power supply unit 14, in the same manner as in the first embodiment.

[0105] According to the power transmission device 10 of the fourth embodiment described above, the inductor constituting the phase advancement unit 50 is provided only for the second power transmission electrode pair 12b located on the furthest side of the high-frequency power supply unit 14, thereby achieving the same effects as in the third embodiment.

[0106] Furthermore, the power transmission device 10 according to the fourth embodiment has the same configuration as the power transmission devices 10 according to the first and second embodiments and achieves the same effects. Also, the contactless power supply system 1 equipped with the power transmission device 10 according to the fourth embodiment achieves the effects of the power transmission device 10.

[0107] (Fifth embodiment) Next, with reference to Figures 9 and 10, a power transmission device 10 according to the fifth embodiment of the present invention will be described. Figure 9(a) is an equivalent circuit diagram of the power transmission device 10, Figure 9(b) is a schematic perspective view showing an example of the implementation of the power transmission device 10, Figure 10(a) is a schematic perspective view showing another example of the implementation of the power transmission device 10, and Figure 10(b) is a schematic perspective view showing yet another example of the implementation of the power transmission device 10.

[0108] In Figures 9 and 10, the same reference numerals are used for components identical to those in the power transmission device 10 of the first to fourth embodiments, and their explanation is omitted here. Furthermore, the contactless power supply system 1 according to the fifth embodiment is identical in configuration to the contactless power supply system 1 according to the first embodiment, except that the power transmission device 10 of the fifth embodiment is used instead of the power transmission device 10 of the first to fourth embodiments; therefore, its explanation is omitted.

[0109] In the third and fourth embodiments, the inductors of the phase-advancing unit 50 connected in parallel to each second power transmission electrode pair 12b in the first or second embodiment are combined into a single inductor, and the combined inductor is provided only to the second power transmission electrode pair 12b located on the nearest or furthest side of the high-frequency power supply unit 14.

[0110] In contrast, in the fifth embodiment, as shown in the equivalent circuit of Figure 9(a), the inductors of the phase-advancing unit 50 connected in parallel to each second power-transmitting electrode pair 12b in the first or second embodiment are combined into two inductors, one of which is provided on the second power-transmitting electrode pair 12b closest to the high-frequency power supply unit 14, and the other is also provided on the second power-transmitting electrode pair 12b closest to the high-frequency power supply unit 14.

[0111] If the inductance of each inductor is 2L / (n+1), then a phase-advancing unit 50 equivalent to the power transmission device 10 in the first embodiment shown in Figure 2(c) (where a coil 13 with an inductance of 2L is mounted in parallel on the nearest and furthest sides of the high-frequency power supply unit 14, and n coils 13 with an inductance of L are mounted in parallel elsewhere) can be constructed in the fifth embodiment. Note that the inductances of the two inductors do not necessarily have to be 2L / (n+1); it is sufficient that the combined inductance of these two inductors is L / (n+1).

[0112] Even when the two combined inductors are provided on the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14 and the second power transmission electrode pair 12b located furthest away, similar to the third and fourth embodiments, the two inductors and the capacitors 51 formed by the overlap of the adjacent first power transmission electrode 11 and second power transmission electrode 12 work together to advance the phase of the high-frequency power, thereby suppressing the generation of voltage standing waves in the power transmission electrode unit 40.

[0113] The inductor of the phase-advancing unit 50 according to this fifth embodiment may be implemented, for example, as shown in Figure 9(b), by connecting one coil 13 with inductance 2L / (n+1) between the second power transmission electrodes 12 of the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14, and another coil 13 with inductance 2L / (n+1) between the second power transmission electrodes 12 of the second power transmission electrode pair 12b located furthest from the high-frequency power supply unit 14, in the same manner as in the first embodiment.

[0114] Furthermore, as shown in Figure 10(a), if a ground plate 19 similar to that of the second embodiment is provided, the first coil 13a and the second coil 13b, having an inductance of L / (n+1), may be connected between the second power transmission electrode 12 of the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14 via the ground plate 19, similar to Figure 4(a) of the second embodiment. The first coil 13a and the second coil 13b, having an inductance of L / (n+1), may also be connected between the second power transmission electrode 12 of the second power transmission electrode pair 12b located furthest from the high-frequency power supply unit 14 via the ground plate 19, similar to Figure 4(a) of the second embodiment.

[0115] Furthermore, the first coil 13a and the second coil 13b, which are mounted on the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14, may have any individual inductance as long as their combined inductance is L / (n+1). Similarly, the first coil 13a and the second coil 13b, which are mounted on the second power transmission electrode pair 12b located furthest from the high-frequency power supply unit 14, may also have any individual inductance as long as their combined inductance is L / (n+1).

[0116] Furthermore, even if a ground plate 19 is provided, as shown in Figure 10(b), it may be implemented by connecting one coil 13 with inductance 2L / (n+1) between the second power transmission electrodes 12b of the second power transmission electrode pairs 12b located on the nearest and furthest sides of the high-frequency power supply unit 14, in the same manner as in the first embodiment.

[0117] The power transmission device 10 according to the fifth embodiment described above provides the following effects.

[0118] (7) Since the inductors constituting the phase advancement unit 50 are provided only for the second power transmission electrode pair 12b located closest to the high-frequency power supply unit 14 and the second power transmission electrode pair 12b located furthest away, the number of components can be reduced compared to the first and second embodiments, and costs can be lowered. Furthermore, the ease of mounting can also be improved.

[0119] (8) By combining one inductor into two inductors, the required inductance for that inductor can be reduced to 2L / (n+1). Therefore, compared to the first and second embodiments, the coil 13 or the first coil 13a and second coil 13b required to mount the inductor can be reduced. Therefore, cost reduction and ease of mounting can be improved.

[0120] (9) Since the phase advance unit 50 is composed of two inductors, it is possible to advance the phase of high-frequency power with greater precision compared to the third and fourth embodiments which are composed of one inductor.

[0121] Furthermore, the power transmission device 10 according to the fifth embodiment has the same configuration as the power transmission devices 10 according to the first and second embodiments and achieves the same effects. Also, the contactless power supply system 1 equipped with the power transmission device 10 according to the fifth embodiment achieves the effects of the power transmission device 10.

[0122] (Sixth Embodiment) Next, with reference to Figure 11, a power transmission device 10 according to the sixth embodiment of the present invention will be described. Figure 11(a) is a schematic plan view showing the printed pattern coil 13c constituting the phase advancement section 50 of the power transmission device 10, and Figure 11(b) is a cross-section view when cut along the cutting line XIb shown in Figure 11(a).

[0123] In Figures 11(a) and (b), the same reference numerals are used for components identical to those in the power transmission device 10 of the first to fifth embodiments, and their explanation is omitted here. Furthermore, the contactless power supply system 1 according to the sixth embodiment has the same configuration as the contactless power supply system 1 according to the first embodiment, except that the power transmission device 10 of the sixth embodiment is used instead of the power transmission device 10 of the first to fifth embodiments; therefore, its explanation is omitted.

[0124] In the first to fifth embodiments, the case in which a three-dimensional coil 13, a first coil 13a, and a second coil 13b made of an air core or ferrite core is used as the inductor of the phase-advancing unit 50 was described. In contrast, in the sixth embodiment, the coil 13, the first coil 13a, and the second coil 13b are composed of printed pattern coils 13c formed by patterns printed on a printed circuit board 60.

[0125] For example, as shown in Figures 11(a) and (b), a printed circuit board 60 is provided between a pair of second power transmission electrodes 12, and a rectangular coil pattern made of conductors is printed on the printed circuit board 60 to form a printed pattern coil 13c.

[0126] Furthermore, one end of the printed pattern coil 13c formed on the printed circuit board is connected to one of the pair of second power transmission electrodes 12, and the other end of the printed pattern coil 13c is connected to the other of the pair of second power transmission electrodes 12, so that the printed pattern coil 13c functions in the same way as the coil 13 of the phase advancement unit 50 in the first embodiment.

[0127] Furthermore, one end of the printed pattern coil 13c formed on the printed circuit board is connected to one or the other of the pair of second power transmission electrodes 12, and the other end of the printed pattern coil 13c is connected to the ground plate 19 (see Figure 4(a)), so that the printed pattern coil 13c functions in the same way as the first coil 13a or the second coil 13b of the phase advancement unit 50 in the second embodiment.

[0128] The power transmission device 10 according to the sixth embodiment described above provides the following effects.

[0129] (10) Since the inductor of the phase advancement unit 50 is composed of a printed pattern coil 13c formed by a pattern printed on the printed circuit board 60, the inductor is flattened. Therefore, the volume required for mounting the inductor can be reduced, making it easier to mount the inductor.

[0130] Furthermore, the power transmission device 10 according to the sixth embodiment has the same configuration as the power transmission devices 10 according to the first to fifth embodiments and achieves the same effects. In addition, the contactless power supply system 1 equipped with the power transmission device 10 according to the sixth embodiment achieves the effects of the power transmission device 10.

[0131] (modified version) Although the present invention has been described above based on embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention.

[0132] For example, each embodiment may be configured by modifying it by adding or replacing some or more parts of the configuration of other embodiments with those of other embodiments. Furthermore, the numerical values ​​given in the above embodiments are merely examples, and it is naturally possible to use other numerical values.

[0133] For example, in each of the above embodiments, the power transmission electrode section 40 was described in which the first power transmission electrode 11 is formed in the first power transmission electrode forming layer 11a and the second power transmission electrode 12 is formed in the second power transmission electrode forming layer 12a which is at a different position (depth) from the first power transmission electrode forming layer 11a, that is, the power transmission electrode is formed in two layers. However, the power transmission electrode may be composed of three or more layers. In this case, adjacent power transmission electrodes are formed in different layers, and the capacitor 51 of the phase advancement section 50 can be formed by capacitive coupling due to the overlap of adjacent power transmission electrodes.

[0134] Further, the second power transmission electrode 12 may be formed so as to span across a plurality of layers while sandwiching the first power transmission electrode 11. For example, as shown in FIG. 12(a), a second lower layer power transmission electrode 12c is formed in the lower layer of the first power transmission electrode 11, and a second upper layer power transmission electrode 12d is formed in the upper layer of the first power transmission electrode 11. The second lower layer power transmission electrode 12c and the second upper layer power transmission electrode 12d are conductors on a flat plate having the same area, and are laminated so that the overlapping area between the first power transmission electrode 11 and the second lower layer power transmission electrode 12c is the same as the overlapping area between the first power transmission electrode 11 and the second upper layer power transmission electrode 12d. Further, the second lower layer power transmission electrode 12c and the second upper layer power transmission electrode 12d are electrically connected by a conductor 12e.

[0135] As a result, a capacitor of capacitance C is formed by capacitive coupling due to the overlap between the first power transmission electrode 11 and the second lower layer power transmission electrode 12c L and a capacitor of capacitance C is formed by capacitive coupling due to the overlap between the first power transmission electrode 11 and the second upper layer power transmission electrode 12d. Here, the second lower layer power transmission electrode 12c and the second upper layer power transmission electrode 12d can be regarded as one second power transmission electrode 12 due to the connection by the conductor 12e, and a capacitance (C U ) is formed between the second power transmission electrode 12 regarded as one and the first power transmission electrode 11, which is equivalent to the case where a capacitor of capacitance (C L +C U ) is formed.

[0136] And when it can be ensured that the distance between the second upper layer power transmission electrode 12d and the second lower layer power transmission electrode 12c is kept constant, when the first power transmission electrode 11 is formed farther from the second lower layer power transmission electrode 12c than designed and closer to the second upper layer power transmission electrode 12d, although the capacitance C L decreases, the decrease is absorbed by the capacitance C U . Also, when the first power transmission electrode 11 is formed closer to the second lower layer power transmission electrode 12c than designed and farther from the second upper layer power transmission electrode 12d, although the capacitance C U increases, the capacitance C LThe increase is absorbed by this. As a result, the capacitance (C) between the second power transmission electrode 12 and the first power transmission electrode 11, which are considered as one, is absorbed. L +C U Since this value is kept approximately constant, a phase advance unit 50 can be configured that can advance the phase of high-frequency power with high accuracy.

[0137] As shown in Figure 12(b), the conductor 12e does not necessarily have to be provided, and the second upper transmission electrode 12d and the second lower transmission electrode 12c may exist independently. Even in this case, the second lower transmission electrode 12c and the second upper transmission electrode 12d can be virtually considered as one second transmission electrode 12, and the same effects and advantages as in Figure 12(a) can be obtained.

[0138] In the embodiments described above, the inductors of the phase-advancing unit 50 were either provided for all second power transmission electrode pairs 12b or only for the nearest and / or furthest second power transmission electrode pairs 12b of the high-frequency power supply unit 14. However, the invention is not limited to these cases, and the inductors of the phase-advancing unit 50 may be provided for any second power transmission electrode pairs 12b. For example, the second power transmission electrode pairs 12b may be grouped into predetermined units, and the inductors within each predetermined unit may be combined into a single inductor and provided for one second power transmission electrode pair 12b included in the predetermined unit. Reducing the number of inductors reduces the number of components used, thereby lowering costs, and also increases the flexibility of inductor mounting. On the other hand, by using multiple inductors as appropriate, a phase-advancing unit 50 that can accurately advance the phase of high-frequency power can be constructed. [Explanation of Symbols]

[0139] 1. Contactless power supply system 10 Power transmission equipment 11. First power transmission electrode 11a First power transmission electrode forming layer 11b First power transmission electrode pair 12. Second power transmission electrode 12a 2nd power transmission electrode forming layer 12b Second power transmission electrode pair 13. Coil (Inductor) 13a First coil (part of the inductor) 13b Second coil (part of the inductor) 13c Printed Pattern Coil 14 High frequency power supply section 19 Groundboard 20 Power receiving equipment 21 Receiving electrode 31 Battery (Load) 40 Power transmission electrode section 50 Leading phase part 51 Capacitors

Claims

1. A power transmission device that transmits power to a power receiving device equipped with power receiving electrodes that receive power and supplies the received power to a load, using an electric field coupling method in a non-contact manner, A power transmission electrode section is configured by connecting multiple power transmission electrodes in series to transmit power to the power receiving electrode, It comprises a high-frequency power supply unit that supplies high-frequency power to the power transmission electrode section, The aforementioned power transmission electrode section is A plurality of power transmission electrode forming layers on which the power transmission electrodes are formed, The system includes a phase advance unit for advancing the phase of the supplied high-frequency power, located at least in part between adjacent power transmission electrodes connected in cascade, The phase advancement unit includes a capacitor connected in series with the power transmission electrode, The power transmission device is characterized in that the capacitor is formed by capacitive coupling obtained from the overlap of adjacent power transmission electrodes formed on different power transmission electrode forming layers.

2. The power transmission electrode section consists of a pair of power transmission electrodes, and power supplied from the high-frequency power supply section is transmitted to this power transmission electrode pair. Multiple pairs of power transmission electrodes are connected in series, such that one power transmission electrode of one pair is connected in series with one power transmission electrode of an adjacent pair, and the other power transmission electrode is connected in series with the other power transmission electrode of the adjacent pair. The power transmission device according to claim 1, characterized in that the phase advancement portion is provided in at least a portion of the space between adjacent pairs of power transmission electrodes connected in cascading.

3. The phase advancement unit includes an inductor that works in cooperation with the capacitor to advance the phase of the high-frequency power. The power transmission device according to claim 2, characterized in that the inductor is formed between a pair of power transmission electrodes provided on a predetermined power transmission electrode pair.

4. The power transmission device according to claim 3, characterized in that the inductor is composed of a single coil, one end of which is connected to one of the pair of power transmission electrodes and the other end of which is connected to the other of the pair of power transmission electrodes.

5. Equipped with a ground plate maintained at a reference potential, The aforementioned inductor is A first coil, one end of which is connected to one of the pair of power-transmitting electrodes and the other end of which is connected to the ground plate, The power transmission device according to claim 3, further comprising a second coil, one end of which is connected to the other of the pair of power transmission electrodes, and the other end of which is connected to the ground plate.

6. The power transmission device according to claim 5, characterized in that the ground plate is formed on the side opposite to the side facing the power receiving electrode with respect to the power transmission electrode forming layer, and includes a region that overlaps with the power transmission electrode when viewed from the power receiving electrode side.

7. The power transmission device according to claim 3, characterized in that the inductor is provided only with respect to the power transmission electrode pair that is closest to and / or furthest from the high-frequency power supply unit, as the predetermined power transmission electrode pair.

8. The power transmission device according to claim 3, characterized in that the inductor is composed of a printed pattern coil formed by a pattern printed on a printed circuit board.

9. A contactless power supply system that supplies power to a load without contact, A power transmission device according to any one of claims 1 to 8, A contactless power supply system characterized by comprising a receiving electrode that receives power transmitted from the transmitting electrode of a power transmission device in a contactless manner using an electric field coupling method, and a receiving device that supplies the received power to the load.

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