WO2019189374A1 - Power transmission module, power transmission device, and wireless power transfer system - Google Patents

Abstract

This power transmission module is used for a power transmission device in a wireless power transfer system that can simultaneously transfer energy to two or more power reception electrode groups from a power transmission electrode group wirelessly via an electric field. The power transmission module is provided with: the power transmission electrode group that includes two or more power transmission electrodes; a first matching circuit connected between a first power conversion circuit that outputs a first AC voltage and the power transmission electrode group; and a second matching circuit connected between the power transmission electrode group and the first power conversion circuit or a second power conversion circuit that outputs a second AC voltage. The first and second matching circuits supply AC energies of the same phase to the power transmission electrode group.

Description

Power transmission module, power transmission device, and wireless power transmission system

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

In recent years, 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 has been promoted. Wireless power transmission techniques include a magnetic field coupling method and an electric field coupling method. In a wireless power transmission system using a magnetic field coupling method, AC power is transmitted from a power transmission coil to a power reception coil in a contactless manner with the power transmission coil and the power reception coil facing each other. Patent Document 1 discloses an example of a magnetic field coupling type wireless power transmission system. On the other hand, in a wireless power transmission system using an electric field coupling method, AC power is wirelessly transmitted from a pair of power transmission electrodes to a pair of power reception electrodes in a state where the pair of power transmission electrodes and the pair of power reception electrodes face each other. Patent Document 2 discloses an example of a wireless power transmission system using such an electric field coupling method.

JP 2017-147848 A JP 2010-193692 A

This disclosure provides a technique for suppressing a reduction in transmission efficiency when power is transmitted simultaneously from one power transmission device to two or more power reception devices in a wireless power transmission system using an electric field coupling method.

The power transmission module according to an aspect of the present disclosure is used in a power transmission device in a wireless power transmission system capable of wirelessly transmitting energy from a power transmission electrode group to two or more power reception electrode groups via an electric field. The power transmission module includes a power transmission electrode group including two or more power transmission electrodes, a first power conversion circuit that outputs a first AC voltage, and a first matching circuit connected between the power transmission electrode group. And a second matching circuit connected between the first power conversion circuit or the second power conversion circuit that outputs a second AC voltage and the power transmission electrode group. The first and second matching circuits supply in-phase AC energy to the power transmission electrode group.

The comprehensive or specific aspect of the present disclosure can be realized by an apparatus, a system, a method, an integrated circuit, a computer program, or a recording medium. Alternatively, the present invention may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

According to the technique of the present disclosure, in a wireless power transmission system using an electric field coupling method, it is possible to suppress a decrease in transmission efficiency when power is transmitted simultaneously from one power transmission device to two or more power reception devices.

FIG. 1 is a diagram schematically illustrating an example of a wireless power transmission system using an electric field coupling method. FIG. 2 is a diagram illustrating a schematic configuration of the wireless power transmission system illustrated in FIG. 1. FIG. 3 is a diagram schematically illustrating another example of the wireless power transmission system using the electric field coupling method. 4 is a diagram showing a schematic configuration of the wireless power transmission system shown in FIG. FIG. 5 is a diagram illustrating a situation in which two mobile objects are simultaneously receiving power from the power transmission electrode group. FIG. 6 is a diagram for explaining a problem that occurs when two moving bodies simultaneously receive power from the power transmission electrode group. FIG. 7A is a schematic diagram of a wireless power transfer system in an exemplary embodiment of the present disclosure. FIG. 7B is a schematic diagram of a wireless power transmission system according to another exemplary embodiment of the present disclosure. FIG. 8A is a diagram illustrating a first configuration example of the matching circuit. FIG. 8B is a diagram illustrating a second configuration example of the matching circuit. FIG. 8C is a diagram illustrating a third configuration example of the matching circuit. FIG. 8D is a diagram illustrating a fourth configuration example of the matching circuit. FIG. 8E is a diagram illustrating a fifth configuration example of the matching circuit. FIG. 8F is a diagram illustrating a sixth configuration example of the matching circuit. FIG. 8G is a diagram illustrating a seventh configuration example of the matching circuit. FIG. 8H is a diagram illustrating an eighth configuration example of the matching circuit. FIG. 8I is a diagram illustrating a ninth configuration example of the matching circuit. FIG. 9 is a diagram schematically illustrating a configuration example of two inductors in the matching circuit. FIG. 10A is a diagram illustrating a configuration example of a wireless power transmission system. FIG. 10B is a diagram illustrating another configuration example of the power transmission device. FIG. 11 is a diagram schematically illustrating a configuration example of an inverter circuit. FIG. 12 is a diagram schematically illustrating a configuration example of the rectifier circuit. FIG. 13A is a diagram illustrating a modification of the wireless power transmission system. FIG. 13B is a diagram illustrating another modification of the wireless power transmission system. FIG. 14A is a diagram illustrating still another modification of the wireless power transmission system. FIG. 14B is a diagram illustrating still another modification of the wireless power transmission system.

(Knowledge that became the basis of this disclosure)
Prior to describing the embodiments of the present disclosure, the knowledge underlying the present disclosure will be described.

FIG. 1 is a diagram schematically showing an example of a wireless power transmission system using an electric field coupling method. “Electric field coupling method” refers to electric field coupling (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 transmitted wirelessly. For simplicity, an example will be described in which each of the power transmission electrode group and the power reception electrode group is configured by a pair of two electrodes.

The wireless power transmission system shown in FIG. 1 is a system that wirelessly transmits power to a moving body 10 that is an automated guided vehicle (AGV). The mobile body 10 can be used for conveying articles in a factory or a warehouse, for example. In this system, a pair of flat power transmission electrodes 120 a and 120 b are arranged on the floor 30. The moving body 10 includes a pair of power receiving electrodes facing the pair of power transmitting electrodes 120a and 120b during power transmission. The moving body 10 receives the AC power transmitted from the pair of power transmission electrodes 120a and 120b by the pair of power reception electrodes. The received electric power is supplied to a load such as a motor, a secondary battery, or a capacitor for electric storage provided in the moving body 10. Thereby, driving or charging of the moving body 10 is performed.

FIG. 1 shows XYZ coordinates indicating X, Y, and Z directions orthogonal to each other. In the following description, illustrated XYZ coordinates are used. The direction in which each power transmission electrode extends is defined as the Y direction, the direction perpendicular to the surface of each power transmission electrode is defined as the Z direction, and the direction perpendicular to the Y direction and the Z direction, that is, the width direction of the power transmission electrode is defined as the X direction. Note that the orientation of the structure shown in the drawings of the present application is set in consideration of the ease of explanation, and does not limit the orientation when the embodiment of the present disclosure is actually implemented. Further, the shape and size of the whole or a part of the structure shown in the drawings do not limit the actual shape and size.

FIG. 2 is a diagram showing a schematic configuration of the wireless power transmission system shown in FIG. The wireless power transmission system includes a power transmission device 100 and a moving body 10.

The power transmission device 100 includes a power transmission electrode group 120, a matching circuit 180, and an inverter circuit 110. The power transmission electrode group 120 includes a pair of power transmission electrodes 120a and 120b. The inverter circuit 110 converts the DC power output from the power source 310 into AC power and outputs the AC power. The power source 310 may be an AC power source. In that case, instead of the inverter circuit 110, the input AC power is converted into, for example, another AC power having a different frequency or voltage and output. Matching circuit 180 is connected between inverter circuit 110 and power transmission electrode group 120. The matching circuit 180 improves the degree of impedance matching between the inverter circuit 110 and the power transmission electrode group 120. A filter circuit for removing noise components may be inserted.

The moving body 10 includes a power receiving device 200 and a load 330. The power receiving device 200 includes a power receiving electrode group 220, a matching circuit 280, a rectifier circuit 210, and a DC / DC converter 270. The power receiving electrode group 220 includes a pair of power receiving electrodes 220a and 220b. The rectifier circuit 210 converts AC power received by the pair of power receiving electrodes 220 into DC power and outputs the DC power. The DC / DC converter 270 converts the DC power output from the rectifier circuit 210 into DC power having a voltage required by the load 330 and supplies the DC power to the load 330. Instead of the rectifier circuit 210 and the DC / DC converter 270, another type of conversion circuit such as an AC conversion circuit may be provided. A matching circuit 280 that reduces impedance mismatch is connected between the power receiving electrode group 220 and the rectifier circuit 210. A filter circuit for removing noise components may be inserted.

The load 330 is a device that consumes or stores electric power, such as a motor, a capacitor for power storage, or a secondary battery. The load 330 is charged or driven by electric power transmitted by electric field coupling between the power transmission electrode group 120 and the power reception electrode group 220.

In this example, each of the power transmission electrodes 120a and 120b is disposed substantially parallel to the floor surface 30, but may be disposed so as to intersect the floor surface 30. For example, when arranged on a wall, each power transmission electrode 120 a, 120 b can be arranged substantially perpendicular to the floor surface 30. Similarly, each of the power receiving electrodes 220a and 220b in the moving body 10 may be disposed so as to intersect the floor surface. The arrangement of the power receiving electrodes 220a and 220b is determined to be an arrangement facing the power transmitting electrodes 120a and 120b.

Each of the power transmitting electrodes 120a and 120b and the power receiving electrodes 220a and 220b may be divided into two or more parts. For example, you may employ | adopt a structure as shown in FIG. 3 and FIG.

FIG. 3 is a perspective view showing an example of a wireless power transmission system in which each of the power transmitting electrodes 120a and 120b and the power receiving electrodes 220a and 220b is divided into two parts. FIG. 4 is a diagram schematically showing a circuit configuration in this example. In this example, the power transmission device 100 includes two first power transmission electrodes 120a and two second power transmission electrodes 120b. Similarly, the power receiving apparatus 200 includes two first power receiving electrodes 220a and two second power receiving electrodes 220b. During power transmission, the two first power receiving electrodes 220a are opposed to the two first power transmitting electrodes 120a, respectively, and the two second power receiving electrodes 220b are respectively opposed to the two second power transmitting electrodes 120b. The matching circuit 180 includes two terminals that output 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. During power transmission, the matching circuit 180 applies the first voltage to the two first power transmission electrodes 120a, and the second voltage having the opposite phase to the first voltage to the two second power transmission electrodes 120b. Apply voltage. Thereby, electric power is wirelessly transmitted by capacitive coupling between the power transmission electrode group 120 including four power transmission electrodes and the power reception electrode group 220 including four power reception electrodes. According to such a configuration, it is possible to obtain an effect of suppressing a leakage electric field on the boundary between any two adjacent power transmission electrodes. Thus, in each of the power transmission device 100 and the power reception device 200, the number of powers to be transmitted or received is not limited to two.

In the following embodiment, as illustrated in FIGS. 1 and 2, a configuration in which the power transmission device 100 includes two power transmission electrodes 120a and 120b and the power reception device 200 includes two power reception electrodes 220a and 220b will be mainly described. . In the embodiment of the present disclosure, each electrode may be divided into a plurality of parts as illustrated in FIGS. 3 and 4. In either case, the electrodes to which the first voltage is applied at a certain moment and the electrodes to which the second voltage having the opposite phase to the first voltage are alternately arranged are arranged. Here, the “reverse phase” is defined not only when the phase difference is 180 degrees but also including the case where the phase difference is in the range of 90 degrees to 270 degrees. In this specification, a plurality of power transmission electrodes included in the power transmission device 100 are collectively referred to as “power transmission electrode group 120”, and a plurality of power reception electrodes included in the power reception device 200 are collectively referred to as “power reception electrode group 220”.

In the wireless power transmission system as described above, the power transmission device 100 is designed so that power can be efficiently transmitted to one moving body 10. Values such as inductance and capacitance of each circuit element in the matching circuit 180 are optimized so that power can be transmitted from the power transmission apparatus 100 to one mobile body 10 with high efficiency. In addition, a shielding member for suppressing electric field leakage may be disposed in the vicinity of the power transmission electrode group 120.

On the other hand, the power transmission electrode group 120 in the power transmission device 100 has a dimension longer than the dimension in the moving direction of the moving body 10. For example, the power transmission electrode group 120 may have a size that is approximately twice to 100 times the size of the moving body 10 in the moving direction. By using such a long power transmission electrode group 120, the mobile body 10 can be charged while moving. Considering that such a long power transmission electrode group 120 is laid, if power can be supplied from the power transmission electrode group 120 to two or more moving bodies 10 simultaneously, the convenience of the system can be greatly improved.

However, if power is transmitted from the power transmission electrode group 120 to two or more moving bodies 10 at the same time, impedance mismatch occurs, and transmission efficiency is greatly reduced. For this reason, such a system could not be realized conventionally.

FIG. 5 shows a situation where two mobile bodies 10A and 10B are about to receive power from the pair of power transmission electrodes 120a and 120b at the same time. FIG. 6 schematically shows the configuration of the system at this time. In FIG. 6, “TX” indicates a component of the power transmission device 100, and “RX” indicates a component of the power reception device 200.

As shown in FIG. 6, a situation is considered in which the second moving body 10B is approaching the power transmission electrode group 120 in a state where the power receiving electrode group 220 of the first moving body 10A faces the power transmission electrode group 120.

The power transmission device 100 is designed in advance so as to increase the transmission efficiency when energy is transmitted to the first moving body 10A via the coupling capacitance between the power transmission electrode group 120 and the power reception electrode group 220. In other words, the matching circuit 180 on the power transmission side includes a resonance circuit optimized for energy transmission with a predetermined impedance. Also for the first moving body 10A, the matching circuit 280 on the power receiving side includes a resonance circuit optimized for energy transmission with a predetermined impedance in advance.

In order for the power transmission device 100 to achieve high-efficiency energy transmission to the second moving body 10B as well, the same conditions as those for the first moving body 10A are set in the second moving body 10B. Must also be realized. That is, the matching circuit 280 in the second moving body 10B also needs to have a resonance circuit optimized for energy transmission with the predetermined impedance. In a wireless power transmission system having a resonance circuit in a matching circuit, a high transmission efficiency is obtained in a one-to-one relationship between the individual mobile bodies 10A and 10B and the power transmission device 100 under a condition that basically maintains a constant impedance. It is possible to achieve good transmission with

However, if the power receiving electrode group 220 of the second moving body 10B faces the power transmitting electrode group 120 and, for example, the same power supply as that of the first moving body 10A is requested, the power supplied from the power transmitting apparatus 100 is 2 Double. As a result, the inter-electrode voltage difference Vtx of the power transmission electrode group 120 increases by √2. Then, an impedance mismatch clearly occurs between the matching circuit 180 of the power transmission device 100 and the matching circuit 280 of each of the mobile bodies 10A and 10B. As a result, the efficiency of power transmission to each mobile unit 10A, 10B is greatly reduced. The decrease in power transmission efficiency leads to serious heat generation on the moving body side.

Furthermore, if the voltage difference Vtx between the electrodes fluctuates, the behavior of the leakage electric field particularly around the power transmission electrode changes. In particular, due to an increase in the inter-electrode voltage difference Vtx, a leakage countermeasure shielding method designed for the condition of transmitting power to one mobile body may not sufficiently suppress electromagnetic leakage to the surrounding space. . Further, when the inter-electrode voltage difference Vtx of the power transmission electrode group 120 becomes high, Vtx approaches or exceeds the threshold that can maintain insulation. In that case, reliability problems such as shortening of the life of the apparatus may be caused.

As described above, when two or more moving bodies 10 simultaneously receive power from one power transmission device 100, impedance mismatch occurs. As a result, at least one of an unfavorable situation such as a significant decrease in transmission efficiency, an increase in heat generation, a decrease in the level of suppression of electric field leakage around the transmission electrode group 120, or an increase in the voltage difference between the electrodes of the transmission electrode group 120 is caused. It might be.

The inventors of the present invention have found the above-mentioned problems and have conceived the configuration of each embodiment described below in order to solve the above problems.

The power transmission module according to an aspect of the present disclosure is used in a power transmission device in a wireless power transmission system capable of wirelessly transmitting energy from a power transmission electrode group to two or more power reception electrode groups via an electric field. The power transmission module includes a power transmission electrode group including two or more power transmission electrodes, a first matching circuit, and a second matching circuit. The first matching circuit is connected between a first power conversion circuit that outputs a first AC voltage and the power transmission electrode group. The second matching circuit is connected between the first power conversion circuit or the second power conversion circuit that outputs a second AC voltage and the power transmission electrode group. The first and second matching circuits supply in-phase AC energy to the power transmission electrode group.

By providing such a power transmission module in the power transmission device, it is possible to suppress a reduction in power transmission efficiency when two or more power receiving electrode groups are opposed to the power transmitting electrode group.

When the number of matching circuits is two, the transmission efficiency decreases when three or more power receiving electrode groups face the power transmitting electrode group. However, even in that case, the efficiency is improved as compared with the case where the second matching circuit is not provided.

”Here,“ in-phase AC energy ”does not mean AC energy whose phases are exactly the same. In the present disclosure, if the phase difference between the two is less than 45 degrees, it is interpreted as “the same phase”.

The power transmission device may or may not include the first power conversion circuit. Similarly, the power transmission device may or may not include the second power conversion circuit. When the power transmission device includes the second power conversion circuit, the second matching circuit is connected to the second power conversion circuit. When the power transmission device does not include the second power conversion circuit, the second matching circuit is connected to the first power conversion circuit.

Each of the first and second power conversion circuits may be an inverter circuit as described above, for example. In this case, each power conversion circuit converts DC energy (also referred to as “DC power”) into AC energy (also referred to as “AC power”) and outputs the converted energy. Each power conversion circuit may be an AC conversion circuit that converts AC power into other AC power having a different frequency and / or voltage. In the case of using an AC power supply, such an AC conversion circuit can be used.

A power transmission device according to another aspect of the present disclosure is configured to turn on / off a connection between the power transmission module, the first power conversion circuit, and the first power conversion circuit and the second matching circuit. A switch for switching, and a control circuit for controlling the switch. In this case, the second matching circuit is connected to the first power conversion circuit via the switch.

With such a configuration, whether or not AC energy is supplied from the second matching circuit to the power transmission electrode group is switched according to the number of power reception electrode groups (that is, the number of power reception devices or moving bodies) facing the power transmission electrode group. be able to.

For example, when one power receiving electrode group faces the power transmitting electrode group, the control circuit instructs the switch to turn off the connection between the first power conversion circuit and the second matching circuit. Send. When two or more power receiving electrode groups face the power transmitting electrode group, the control circuit instructs the switch to turn on the connection between the first power conversion circuit and the second matching circuit. Send.

Thereby, the second matching circuit is used only when two or more power receiving electrode groups are opposed to the power transmitting electrode group, and a decrease in transmission efficiency can be suppressed.

A power transmission device according to another aspect of the present disclosure controls the power transmission module, the first power conversion circuit, the second power conversion circuit, and the first and second power conversion circuits, and And a control circuit that outputs AC energy having the same phase from the first and second matching circuits. In this case, the second matching circuit is connected to the second power conversion circuit.

According to the above aspect, two sets of the power conversion circuit and the matching circuit are provided, and AC energy having the same phase is supplied from the first and second matching circuits to the power transmission electrode group. Thereby, the fall of the transmission efficiency in the case where two or more power receiving electrode groups oppose the power transmitting electrode group can be suppressed.

The control circuit drives only the first power conversion circuit and stops the operation of the second power conversion circuit when one power reception electrode group faces the power transmission electrode group. The control circuit drives both the first and second power conversion circuits when two or more power receiving electrode groups face the power transmitting electrode group.

In the above aspect, the second power conversion circuit is stopped when one power receiving electrode group faces the power transmitting electrode group, and the second power conversion circuit when two or more power receiving electrode groups face the power transmitting electrode group. Is driven. That is, whether or not the second power conversion circuit is used is determined according to the number of power receiving electrode groups that receive power (that is, the number of power receiving devices or moving bodies). Thereby, the fall of the transmission efficiency in case two or more receiving electrode groups oppose a power transmission electrode group can be suppressed. In addition, when two or more power receiving electrode groups face the power transmitting electrode group, at least one of an increase in heat generation, a deterioration in the suppression level of electric field leakage around the power transmitting electrode, and an increase in the voltage difference between the electrodes in the power transmitting electrode Can also be suppressed.

The control circuit monitors at least one of voltage, current, and power in the first matching circuit, and the number of power receiving electrode groups facing the power transmitting electrode group based on at least one value of voltage, current, and power May be detected. Or the said control circuit may grasp | ascertain whether it is in a receiving state by communication between the receiving device provided with the said receiving electrode group, or a mobile body.

The control circuit monitors at least one of voltage, current, and power output from each of the first and second matching circuits, and based on at least one value of the voltage, current, and power By controlling the second power conversion circuit and the second power conversion circuit, the phases of the AC energy output from the first and second matching circuits may be matched. For example, when the phase difference of the voltage or current output from each of the first and second matching circuits is larger than a predetermined value, the control circuit is in at least one of the first and second power conversion circuits. The phase difference may be reduced by adjusting the timing of the switching control.

A power transmission device according to another aspect of the present disclosure is a power transmission device in a wireless power transmission system capable of transmitting energy wirelessly from a power transmission electrode group to two or more power reception electrode groups via an electric field. The power transmission device includes a power transmission electrode group including two or more power transmission electrodes, N (N is an integer of 2 or more) AC output circuits that supply AC energy to the power transmission electrode group, and the N AC outputs. And a control circuit for controlling the circuit. When the control circuit transmits energy from the power transmitting electrode group to n power receiving electrode groups simultaneously (n is an integer of 1 to N), n AC output circuits among the N AC output circuits In addition, a command to supply AC energy having the same phase to the power transmission electrode group is sent.

According to the above aspect, when the control circuit transmits energy from the power transmitting electrode group to n power receiving electrode groups (n is an integer of 1 to N) at the same time, of the N AC output circuits. A command for supplying AC energy having the same phase to the power transmission electrode group is sent to n AC output circuits. As a result, only the required number of AC output circuits are activated according to the number of power receiving electrode groups that need to transmit power simultaneously, and a decrease in transmission efficiency can be suppressed.

In this specification, “AC output circuit” widely means a circuit that outputs AC energy. The “AC output circuit” is a concept that includes both the above-described “matching circuit” and “combination of a power conversion circuit and a matching circuit”.

The control circuit may control the N AC output circuits to supply energy of the same intensity to all of the n power receiving electrode groups that receive the energy simultaneously from the power transmitting electrode group, Different strengths of energy may be supplied.

The power transmission device may further include another power transmission electrode group including two or more power transmission electrodes. The N AC output circuits supply AC energy to the other power transmission electrode group, and the control circuit receives n power (n is an integer from 1 to N) simultaneously from the other power transmission electrode group. When transmitting the energy to the electrode group, a command for supplying AC energy having the same phase to the other power transmission electrode group may be sent to n AC output circuits among the N AC output circuits.

The power transmission device may further include a second power transmission electrode group including two or more power transmission electrodes and a third power transmission electrode group including two or more power transmission electrodes. A first AC output circuit of the N AC output circuits may supply AC energy to the second power transmission electrode group. A second AC output circuit of the N AC output circuits may supply AC energy to the third power transmission electrode group. The control circuit instructs the first AC output circuit to supply the AC energy to the second power transmission electrode group when transmitting the energy from the second power transmission electrode group to one power reception electrode group. When the energy is transmitted from the third power transmission electrode group to the other power reception electrode group, a command to supply the AC energy to the third power transmission electrode group is sent to the second AC output circuit. May be.

In each of the above aspects, the power transmission module can be manufactured or sold independently of other components of the power transmission device. That is, the power transmission module can be manufactured or sold independently of, for example, the first power conversion circuit, the second conversion circuit, the switch, the control circuit, or the communication circuit.

A wireless power transmission system according to another aspect of the present disclosure includes the power transmission device according to any one of the above-described aspects and at least one power reception device including a power reception electrode group that wirelessly receives power from the power transmission electrode group. For example, power transmission can be performed between the power transmission electrode group and the power reception electrode group via air or another dielectric.

The power receiving device can be mounted on a moving body, for example. When the power receiving apparatus is a mobile object, the wireless power transmission system may be referred to as a “mobile system”. The “moving body” in the present disclosure is not limited to a vehicle such as the above-described automatic guided vehicle, but means any movable object driven by electric power. The moving body includes, for example, an electric vehicle including an electric motor and one or more wheels. Such a vehicle can be, for example, the aforementioned automated guided vehicle (AGV), electric vehicle (EV), electric cart, and electric wheelchair. The “moving body” in the present disclosure includes a movable object having no wheels. For example, unmanned aircraft (unmanned aerial vehicle: UAV, so-called drone) such as bipedal walking robots and multicopters, manned electric aircrafts, and elevators are also included in the “mobile body”.

Hereinafter, embodiments of the present disclosure will be described in more detail. However, more detailed explanation than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. In addition, the inventors provide the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and these are intended to limit the subject matter described in the claims. is not. In the following description, the same or similar components are denoted by the same reference numerals.

(Embodiment)
FIG. 7A is a diagram illustrating a configuration of a wireless power transmission system in an exemplary embodiment of the present disclosure. This wireless power transmission system includes a power source 310, a power transmission device 100, a first moving body 10A, and a second moving body 10B.

The power transmission device 100 includes a power transmission module 50, a switch 190, and an inverter circuit 110. The power transmission module 50 includes a first matching circuit 180A, a second matching circuit 180B, and a power transmission electrode group 120. A switch (SW) 190 is disposed between the inverter circuit 110 and the second matching circuit 180B. The switch 190 switches on (connected) / off (non-connected) the connection between the inverter circuit 110 and the second matching circuit 180B. The first matching circuit 180A and the second matching circuit 180B have the same configuration. Matching circuits 180 </ b> A and 180 </ b> B supply AC power having the same phase to power transmission electrode group 120.

Each of the moving bodies 10A and 10B in the present embodiment has the same configuration. Each moving body includes a power receiving electrode group 220, a matching circuit 280, a rectifier circuit 210, a DC / DC converter 270, and a load 330.

The switch 190 may be a semiconductor switch such as a MOSFET or an IGBT. The switch 190 is controlled by a control circuit (not shown).

In this embodiment, in a state where only the power receiving electrode group 220 of the first moving body 10A faces the power transmitting electrode group 120, the switch 190 is set to OFF. At this time, AC energy output from the inverter circuit 110 is supplied to the matching circuit 180A, but not supplied to the matching circuit 180B. For this reason, AC energy is supplied to the power transmission electrode group 120 only from the matching circuit 180A. On the other hand, in a state where the power receiving electrode group 220 of both the first moving body 10A and the second moving body 10B is opposed to the power transmitting electrode group 120, the switch 190 is set to ON. At this time, the AC energy output from the inverter circuit 110 is supplied not only to the matching circuit 180A but also to the matching circuit 180B. Thereby, AC energy is supplied to the power transmission electrode group 120 from both the matching circuits 180A and 180B.

In this embodiment, the voltage difference Vtx between the power transmission electrodes hardly changes between when the power is supplied only to the moving body 10A and when the power is supplied to both of the moving bodies 10A and 10B. The transmitted power is approximately doubled, but Vtx is substantially constant, and the current flowing through each power transmission electrode is approximately doubled. This brings about an effect equivalent to that the area of each power transmission electrode is doubled. Unlike the configuration illustrated in FIG. 6, the pressure resistance performance required for the power transmission device 100 does not become serious, and the strength of the leakage electric field to the periphery of the power transmission device 100 does not increase. Further, even when power is supplied to the two mobile bodies 10A and 10B, impedance matching is realized, so that a reduction in transmission efficiency can be suppressed. As a result, the heat generation in each mobile body that occurs when two mobile bodies 10A and 10B are simultaneously charged increases compared to the case where only the mobile body 10A or only the mobile body 10B is charged alone. do not do. Regarding the electrical performance required for the power receiving device mounted on the mobile bodies 10A and 10B, in other words, the electrical performance required for each element in the power receiving device, higher performance is required compared to the case of the single charge specification. do not do.

FIG. 7B is a diagram illustrating another configuration example of the present embodiment. In this example, the power transmission device 100 further includes a second inverter circuit 110B having the same configuration and performance as the first inverter circuit 110A. The power transmission module 50 has the same configuration as the example shown in FIG. 7A. However, the second matching circuit 180B is connected to the second inverter circuit 110B. The switch 190 is connected between the power supply 310 and the second inverter circuit 110B. A control circuit (not shown) turns off the switch 190 and drives only the first inverter circuit 110A when supplying power to only one moving body. On the other hand, when supplying power to the two moving bodies simultaneously, the control circuit turns on the switch 190 and simultaneously drives the inverter circuits 110A and 110B. At this time, control is performed so that AC power having the same phase is output from the matching circuits 180A and 180B. Thereby, the same effect as the example shown to FIG. 7A can be acquired.

7B requires two inverter circuits, but the performance required for each inverter circuit can be kept low. In particular, when handling a high frequency and a high voltage, the configuration of FIG. 7A requires a high-performance inverter circuit 110, but in the configuration of FIG. 7B, a cheaper inverter circuit 110 can be used.

7A and 7B, the switch 190 is not limited to the illustrated position, and may be disposed at other positions. The switch 190 may be disposed at any position as long as the second matching circuit 180B can be disconnected from the power transmission path. In the configuration of FIG. 7B, the switch 190 can be omitted because the operation of the inverter circuit 110B is controlled by the control circuit.

Next, an example of the configuration of each matching circuit 180A, 180B, 280 will be described.

8A to 8I are diagrams showing configuration examples of the matching circuits. Here, description will be made assuming that the matching circuit is provided in the power transmission device 100. For simplicity, an example in which the power transmission electrode group 120 includes two power transmission electrodes 120a and 120b will be described. Hereinafter, the inverter circuit 110 is also referred to as a “power conversion circuit 110”. The matching circuit 280 in the moving body may employ a configuration in which the input side (left side in the figure) and the output side (right side in the figure) are inverted in each of the following configuration examples.

FIG. 8A is a diagram illustrating a first example of a matching circuit. The matching circuit in this example includes a first inductor Lt1, a second inductor Lt2, and a capacitor Ct1. The first inductor Lt1 is connected as a series circuit element between the power transmission electrode 120a and the first terminal 60a of the power conversion circuit 110. The second inductor Lt2 is connected as a series circuit element between the power transmission electrode 120b and the second terminal 60b of the power conversion circuit 110. Capacitor Ct1 is connected as a parallel circuit element between the wiring between power transmission electrode 120a and inductor Lt1 and the wiring between power transmission electrode 120b and inductor Lt2.

The first inductor Lt1 and the second inductor Lt2 are magnetically coupled. The coupling coefficient k of these inductors can be set to a value satisfying, for example, −1 <k <0. The first inductor Lt1 and the second inductor Lt2 can function as a common mode choke filter. In that case, the frequency used for power transmission and the common mode noise in the lower harmonic band can be reduced. In such a configuration, a resonator constituted by the first inductor Lt1, the second inductor Lt2, and the first capacitor Ct1 may be referred to as a “common mode choke resonator”.

FIG. 8B is a diagram illustrating a second example of the matching circuit. This matching circuit further includes a second capacitor Ct2, a third capacitor Ct3, and a third inductor Lt3 in addition to the configuration shown in FIG. 8A. The second capacitor Ct2 is connected as a series circuit element between the first inductor Lt1 and the first terminal 60a. The third capacitor Ct3 is connected as a series circuit element between the second inductor Lt2 and the second terminal 60b. The third inductor Lt3 is connected as a parallel circuit element between the wiring between the first inductor Lt1 and the second capacitor Ct2 and the wiring between the second inductor Lt2 and the third capacitor Ct3. Is done. This configuration can be said to be a configuration in which a high-pass filter having a symmetric circuit configuration is added to the preceding stage of the configuration of the matching circuit shown in FIG. 8A. According to such a configuration, transmission efficiency can be further improved.

FIG. 8C is a diagram illustrating a third example of the matching circuit. This matching circuit further includes a second capacitor Ct2 and a third inductor Lt3 in addition to the configuration shown in FIG. 8A. The second capacitor Ct2 is connected as a series circuit element between the first inductor Lt1 and the first terminal 60a. The third inductor Lt3 is connected as a parallel circuit element between the wiring between the first inductor Lt1 and the second capacitor Ct2 and the wiring between the second inductor Lt2 and the second terminal 60b. Is done. This configuration can be said to be a configuration in which a high-pass filter having an asymmetric circuit configuration is added to the preceding stage of the configuration of the matching circuit shown in FIG. 8A. Compared with the configuration of FIG. 8B, the positive / negative symmetry of the circuit is reduced, but the number of elements can be reduced. Even with such a configuration, the transmission efficiency can be further improved.

FIG. 8D is a diagram illustrating a fourth example of the matching circuit. This matching circuit further includes a third inductor Lt3 and a second capacitor Ct2 in addition to the configuration shown in FIG. 8A. The third inductor Lt3 is connected as a series circuit element between the first inductor Lt1 and the first terminal 60a. The second capacitor Ct2 is connected as a parallel circuit element between the wiring between the first inductor Lt1 and the third inductor Lt3 and the wiring between the second inductor Lt2 and the second terminal 60b. Is done. This configuration can be said to be a configuration in which a low-pass filter having an asymmetric circuit configuration is added to the preceding stage of the configuration of the matching circuit shown in FIG. 8A. Even with such a configuration, the transmission efficiency can be further improved.

FIG. 8E is a diagram showing a fifth example of the matching circuit. This matching circuit includes a third inductor Lt3, a fourth inductor Lt4, and a second capacitor Ct2 in addition to the configuration shown in FIG. 8A. The third inductor Lt3 is connected as a series circuit element between the first inductor Lt1 and the first terminal 60a. The fourth inductor Lt4 is connected as a series circuit element between the second inductor Lt2 and the second terminal 60b. The second capacitor Ct2 is connected as a parallel circuit element between the wiring between the first inductor Lt1 and the third inductor Lt3 and the wiring between the second inductor Lt2 and the fourth inductor Lt4. Is done. The third inductor Lt3 and the fourth inductor Lt4 can also be designed to be coupled with a negative coupling coefficient, for example. This configuration can be said to be a configuration in which a low-pass filter having a symmetric circuit configuration is added to the preceding stage of the configuration of the matching circuit shown in FIG. 8A. Even with such a configuration, the transmission efficiency can be further improved. 8E can also be regarded as a configuration in which the common mode choke resonator shown in FIG. 8A is connected in multiple stages. The number of connected common mode choke resonators is not limited to two and may be three or more.

FIG. 8F is a diagram illustrating a sixth modification of the matching circuit. This matching circuit further includes a third inductor Lt3 in addition to the configuration shown in FIG. 8A. The third inductor Lt3 is connected as a series circuit element between the first inductor Lt1 and the first terminal 60a. In addition to the coupling between the first inductor Lt1 and the second inductor Lt2, for example, when an inductor that is not coupled to the second inductor Lt2 is required for matching, this configuration also improves the transmission efficiency. be able to.

FIG. 8G is a diagram illustrating a seventh modification of the matching circuit. In addition to the configuration shown in FIG. 8A, the matching circuit further includes a series resonance circuit 130s connected to the power conversion circuit 110 and a parallel resonance circuit 140p that is magnetically coupled to the series resonance circuit 130s. The parallel resonant circuit 140p is connected to the first inductor Lt1 and the second inductor Lt2. According to such a configuration, it is possible to further increase the transformation ratio and realize good characteristics.

FIG. 8H is a diagram illustrating an eighth modification of the matching circuit. This matching circuit includes a series resonance circuit 130s connected to the terminals 60a and 60b of the power conversion circuit 110, and a parallel resonance circuit 140p connected to the electrodes 120a and 120b. Series resonant circuit 130s includes an inductor L1 and a capacitor C1 connected in series. The parallel resonant circuit includes an inductor L2 and a capacitor Ct1 connected in parallel. The series resonant circuit 130s and the parallel resonant circuit 140p are magnetically coupled and function as a booster circuit. Even if it is such a structure, the effect of this embodiment can be acquired.

FIG. 8I is a diagram showing a ninth modification of the matching circuit. This matching circuit includes a parallel resonant circuit 130p connected to terminals 60a and 60b of power conversion circuit 110, and a parallel resonant circuit 140p connected to electrodes 120a and 120b. Parallel resonant circuit 130p includes an inductor L1 and a capacitor C1 connected in parallel. Parallel resonant circuit 140p includes an inductor L2 and a capacitor Ct1 connected in parallel. The parallel resonant circuit 130p and the parallel resonant circuit 140p are magnetically coupled to exhibit a boost function resulting from the turns ratio of the inductor L1 and the inductor L2, and realize impedance matching between the power supply circuit and the power transmission electrode. Even if it is such a structure, the effect of this embodiment can be acquired.

In addition to the circuit elements shown in the drawings, the matching circuit in each of the above examples may include other circuit elements, such as a circuit network that performs a filter function. In each figure, the element expressed as one inductor or one capacitor may be a plurality of inductors or a collection of a plurality of capacitors.

Next, the configuration of the inductors Lt1 and Lt2 shown in FIGS. 8A to 8G will be described more specifically. The inductors Lt1 and Lt2 can also function as a common mode choke filter that couples with a predetermined coupling coefficient. The inductance values of these inductors Lt1 and Lt2 can be set to substantially equal values.

FIG. 9 is a diagram schematically showing a configuration example of the two inductors Lt1 and Lt2. In this example, two inductors Lt1 and Lt2 are wound around a core 410 that is a ring-shaped or toroidal magnetic body. The core 410 may be, for example, a soft magnetic ferrite core. The inductors Lt1 and Lt2 are arranged in a direction to realize a negative coupling coefficient via the core 410. Specifically, when the coupling coefficient of the inductors Lt1 and Lt2 is k, −1 <k <0. The closer the coupling coefficient k is to -1, the better the transmission efficiency characteristics can be obtained from the viewpoint of transmission efficiency. The coupling coefficient can be measured by, for example, a method defined in JISC5321. When in-phase current is input to the inductors Lt1 and Lt2 from the left input / output terminal of FIG. 9, no in-phase current is output to the right output terminal of FIG. With such a configuration, it is possible to suppress the probability that common mode noise that may occur in the previous stage of the circuit is transmitted to the subsequent stage.

The capacitor Ct1 shown in FIGS. 8A to 8G can be designed to resonate with the leakage inductances of the inductors Lt1 and Lt2. The resonance frequency of the common mode choke resonance circuit configured by the inductors Lt1 and Lt2 and the capacitor Ct1 can be designed to be equal to the frequency f1 of the AC power output from the power conversion circuit 110. This resonance frequency may be set to a value in the range of about 50 to 150% of the transmission frequency f1, for example. The frequency f1 of the power transmission can be set to, for example, 50 Hz to 300 GHz, 20 kHz to 10 GHz in one example, 20 kHz to 20 MHz in another example, and 80 kHz to 14 MHz in another example.

Next, an example of a more detailed configuration of the wireless power transmission system in the present embodiment will be described.

FIG. 10A is a diagram showing an example of a more detailed configuration of the wireless power transmission system shown in FIG. 7A. The power transmission device 100 in this example includes a control circuit 150 that controls the inverter circuit 110 and the switch 190. The control circuit 150 may be an integrated circuit including a microprocessor and a memory, for example. The control circuit 150 may include a measuring instrument that measures at least one of the current, voltage, and voltage in the circuit in each matching circuit 180A, 180B. The control circuit 150 may include a communication circuit that communicates with an external device. The matching circuits 180A and 180B in this example have the configuration shown in FIG. 8B. The matching circuit 280 in the mobile power receiving apparatus 200 has the configuration shown in FIG. 8D. FIG. 10A shows only one moving body, and illustration of the configuration of the other moving bodies is omitted.

When one power receiving electrode group 220 faces the power transmitting electrode group 120, the control circuit 150 sends a command to the switch 190 to turn off the connection between the inverter circuit 110 and the second matching circuit 180B. On the other hand, when the two power receiving electrode groups 220 face the power transmitting electrode group 120, a command to turn on the connection between the inverter circuit 110 and the second matching circuit 180B is sent to the switch 190. The control circuit 150 monitors, for example, at least one of voltage, current, and power in the first matching circuit 180A, and receives power that faces the power transmission electrode group 120 based on at least one value of the measured voltage, current, and power. The number of electrode groups 220 can be detected. For example, the peak value or effective value of the voltage output from the matching circuit 180A can be compared with a threshold value, and the approach of another moving body can be detected based on the comparison result. In addition, the control circuit 150 may detect the approach of another moving body by communicating with another moving body or a central control device that controls the operation of each moving body.

FIG. 10B is a diagram illustrating an example of a more detailed configuration of the power transmission device 100 in the wireless power transmission system illustrated in FIG. 7B. The power transmission device 100 in this example includes a first inverter circuit 110A, a second inverter circuit 110B, and a control circuit 150 that controls the switch 190. The control circuit 150 in this example controls the first inverter circuit 110A and the second inverter circuit 110B to output AC energy having the same phase from the first matching circuit 180A and the second matching circuit 180B. When one power receiving electrode group 220 faces the power transmitting electrode group 120, the control circuit 150 drives only the first inverter circuit 110A, turns off the switch 190, and stops the operation of the second inverter circuit 110B. Let On the other hand, when two or more power receiving electrode groups 220 face the power transmitting electrode group 120, the control circuit 150 drives both the first inverter circuit 110A and the second inverter circuit 110B. The control circuit 150 can detect the power receiving electrode group 220 (that is, the number of moving bodies) facing the power transmitting electrode group 120 based on at least one value of voltage, current, and power in the first matching circuit 180A, for example. it can.

The control circuit 150 performs feedback control for controlling the first and second power conversion circuits based on at least one value of voltage, current, and power output from each of the matching circuits 180A and 180B. Even if the phases of the voltages output from the inverter circuits 110A and 110B match, the phases of the voltages output from the matching circuits 180A and 180B may be shifted depending on the configuration of the matching circuits 180A and 180B. Therefore, for example, the control circuit 150 monitors the voltage output from each of the matching circuits 180A and 180B, and controls the inverter circuits 110A and 111B so as to compensate for the deviation when the deviation occurs. Thereby, the phases of the AC energy output from the matching circuits 180A and 180B can be matched.

FIG. 11 is a diagram schematically illustrating a configuration example of the inverter circuit 110 in the power transmission device 100. In this example, the power source 310 is a DC power source. The inverter circuit 110 is a full bridge type inverter circuit including four switching elements. Each switching element may be constituted by a transistor such as an IGBT or a MOSFET. The control circuit 150 includes a gate driver that outputs a control signal for controlling the conduction (on) and non-conduction (off) states of each switching element, and a processor that causes the gate driver to output a control signal. The processor can be, for example, a CPU in a microcontroller unit (MCU). Instead of the full-bridge inverter circuit shown in FIG. 11, a half-bridge inverter circuit, another oscillation circuit such as class E, or a switching amplifier may be used.

The control circuit 150 may include elements such as a modulation / demodulation circuit for communication and various sensors for measuring voltage or current. In the case where the control circuit 150 includes a communication modulation / demodulation circuit, data can be transmitted to the power receiving device while being superimposed on AC power.

When the power source 310 is an AC power source, instead of the inverter circuit 110, a circuit that converts input AC power into AC power for power transmission having a different frequency or voltage is used.

FIG. 12 is a diagram schematically illustrating a configuration example of the rectifier circuit 210 in the power receiving device 200. In this example, the rectifier circuit 210 is a full-wave rectifier circuit including a diode bridge and a smoothing capacitor, but may have other circuit configurations. In addition, the mobile body 10 may include various circuits such as a constant voltage / constant current control circuit and a communication modulation / demodulation circuit. The rectifier circuit 210 converts the received AC energy into DC energy that can be used by the load 330. Various sensors for measuring voltage, current, and the like may be provided. When the energy used by the load 330 is AC energy, an AC converter circuit is used instead of the rectifier circuit 210.

The DC / DC converter 270 converts the DC power output from the rectifier circuit 210 into other DC power required by the load 330. The DC / DC converter 270 is controlled by a power reception control circuit (not shown). For example, the power reception control circuit controls the output power of the DC / DC converter 270 to be constant. The power reception control circuit can be realized by a circuit including a processor and a memory, such as a microcontroller unit (MCU).

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 (for example, an electric double layer capacitor), a voltage conversion connected to the commercial power source It may be any power source such as a vessel. The power source 310 may be a DC power source or an AC power source.

The size of the casing of the moving body 10, each power transmission electrode, and each power reception electrode is not particularly limited, but may be set to the following size, for example. Each length (size in the Y direction shown in FIG. 1) of the power transmission electrode can be set within a range of 50 cm to 20 m, for example. Each width | variety (size of the X direction shown in FIG. 1) of a power transmission electrode can be set in the range of 0.5 cm to 1 m, for example. Each size in the advancing direction and the lateral direction of the casing of the moving body 10 can be set within a range of 20 cm to 5 m, for example. Each length (that is, the size in the traveling direction) of the power receiving electrode may be set within a range of 5 cm to 2 m, for example. Each width (that is, the size in the lateral direction) of the power receiving electrode can be set within a range of 2 cm to 2 m, for example. The gap between the power transmitting electrode pair and the gap between the power receiving electrode pair can be set within a range of 1 mm to 40 cm, for example. The distance between the power transmitting electrodes 120a and 120b and the power receiving electrodes 220a and 220b can be, for example, about 5 mm to 30 mm. However, it is not limited to these numerical ranges.

The load 330 may include, for example, an electric motor for driving, a capacitor for storing electricity, or a secondary battery. The load 330 is driven or charged by DC power output from the DC / DC converter 270.

The electric motor can be any motor such as a direct current motor, a permanent magnet synchronous motor, an induction motor, a stepping motor, a reluctance motor. The motor rotates the wheels of the moving body 10 via a shaft, gears, and the like to move the moving body 10. Depending on the type of motor, the driving device in the moving body may include various circuits such as a rectifier circuit, an inverter circuit, a DC / DC converter, a control circuit that controls the inverter and the DC / DC converter. The power conversion circuit 210 may include a converter circuit that directly converts the frequency of received energy (that is, AC power) into a frequency for driving the motor in order to drive the AC motor.

The capacitor for power storage can be a high-capacity and low-resistance capacitor such as an electric double layer capacitor or a lithium ion capacitor. By using such a capacitor as a capacitor, it is possible to charge more rapidly than when a secondary battery is used. Instead of the capacitor, a secondary battery such as a lithium ion battery may be used. In this case, the time required for charging increases, but more energy can be stored. The moving body 10 moves by driving a motor with electric power stored in a capacitor for storage or a secondary battery.

When the moving body 10 moves, the storage amount of the storage capacitor or the secondary battery decreases. For this reason, recharging is required to continue the movement. Therefore, when the amount of charge falls below a predetermined threshold during movement, the moving body 10 moves to the vicinity of the power transmission device 100 and performs charging. This movement may be performed under the control of a central control device (not shown), or may be performed by the mobile body 10 autonomously judging. The power transmission device 100 can be installed at a plurality of locations in the factory.

Each inductor in each matching circuit can be, for example, a litz wire made of a material such as copper or aluminum, or a wound coil using a twisted wire. A planar coil or a laminated coil formed on the circuit board may be used. For each capacitor, any type of capacitor having, for example, a chip shape or a lead shape can be used. It is also possible to cause the capacitance between two wirings via air to function as each capacitor.

Next, the effect of this embodiment will be described.

Table 1 shows the results of analysis performed to verify the effects of the present embodiment. For each of the comparative example having the configuration shown in FIG. 6 and the example having the configuration shown in FIG. 7B, the transmission efficiency when power was simultaneously supplied to two moving bodies was compared. As shown in Table 1, in the comparative example, when the number of moving bodies that are charged simultaneously increases from one to two, the efficiency decreases to about half. On the other hand, in the embodiment, even if the number of mobile bodies that perform charging at the same time increases from one to two, the charging efficiency in each mobile body hardly decreases.

Also, the voltage difference Vtx between the power transmission electrodes was analyzed. As a result, according to this example, there was almost no difference in the peak value of Vtx between when power was supplied to one mobile body and when power was simultaneously supplied to two mobile bodies. Specifically, Vtx in the case where only one moving body is charged was 11.2 kV. On the other hand, Vtx when the two moving bodies were charged simultaneously was 10.8 kV. Since the voltage difference between the power transmission electrodes hardly increased, it can be said that the electric field leakage intensity around the power transmission electrodes did not change without depending on the change in the number of mobile bodies to be charged.

From the above results, according to the present embodiment, it is possible to maintain high transmission efficiency even when power is simultaneously supplied to two moving bodies while sharing the power transmission electrode. Furthermore, an increase in the voltage difference between the power transmission electrodes can be prevented, and the system can be operated without deteriorating the electric field strength leaking to the periphery. This effect is not limited to the configuration shown in FIG. 7B but can be obtained in the same manner even when the configuration shown in FIG. 7A is adopted.

Next, a modification of this embodiment will be described.

7A, 7B, 10A, and 10B include two matching circuits 180A and 180B, but may include more matching circuits. The same number of matching circuits are arranged according to the number of mobile bodies 10 that are fed simultaneously. In the configurations shown in FIGS. 7B and 10B, the same number of AC conversion circuits such as inverter circuits are further arranged.

As described above, the power transmission device may include N (N is an integer of 2 or more) AC output circuits that supply AC energy to the power transmission electrode group, and a control circuit that controls the N AC output circuits. . When the control circuit transmits energy from the power transmitting electrode group to n (n is an integer of 1 to N) power receiving electrode groups at the same time, the control circuit transmits the energy to n AC output circuits of the N AC output circuits. Sends a command to supply phase AC energy to the transmission electrode group. Such control can suppress a decrease in efficiency, an increase in voltage difference between power transmission electrodes, and an increase in leakage electric field, regardless of the number of moving bodies that supply power simultaneously. The control circuit can control N AC output circuits to supply energy of the same intensity to all n moving bodies that are simultaneously fed from the power transmission electrode group.

In the above embodiment, the power transmission device 100 includes one power transmission electrode group 120, but the power transmission device 100 may include a plurality of power transmission electrode groups.

FIG. 13A is a diagram schematically illustrating an example of a wireless power transmission system in which the power transmission device 100 includes a plurality of power transmission electrode groups. The power transmission device in this example includes two power transmission electrode groups 120A and 120B and two AC output circuits 170A and 170B. Each AC output circuit includes the matching circuit in the above-described embodiment. Each AC output circuit may include both the matching circuit and the inverter circuit in the above-described embodiment. In this example, the two power transmission electrode groups 120A and 120B extend in the same direction and are arranged in a straight line. Each of AC output circuits 170A and 170B supplies AC power to both power transmission electrode groups 120A and 120B. In each of power transmission electrode groups 120A and 120B, control is performed so that the phase of AC power supplied from AC output circuit 170A matches the phase of AC power supplied from AC output circuit 170B. With such a configuration, each of the power transmission electrode groups 120A and 120B can transmit power to two moving bodies at a high efficiency at the same time. In addition, the length of the chargeable region can be extended by a factor of two. In any of the charging regions defined by the two power transmission electrode groups 120A and 120B laid, power can be transmitted with high efficiency to a plurality of moving bodies that are moving or working. Despite such advantages, it is possible to appropriately reduce the cost for arranging the power supply circuit unit.

In the configuration of FIG. 13A, the number of AC output circuits may be increased according to the number of moving bodies that can be fed simultaneously from each power transmission electrode group. The power transmission device may include N AC output circuits, where N is an integer equal to or greater than 2. In that case, the N AC output circuits supply AC energy to each of the two power transmission electrode groups 120A and 120B shown in FIG. 13A. When the control circuit transmits energy from the power transmission electrode group 120A or 120B to n power receiving electrode groups simultaneously (n is an integer of 1 to N), n AC output circuits among the N AC output circuits. In addition, control is performed so that AC energy having the same phase is supplied to the power transmission electrode group.

FIG. 13B is a diagram schematically illustrating another example of the wireless power transmission system in which the power transmission device 100 includes a plurality of power transmission electrode groups. In this example, the power transmission device 100 includes a first power transmission electrode group 120A, a second power transmission electrode group 120B, a third power transmission electrode group 120C, a first AC output circuit 170A, and a second AC output. Circuit 170B. Each power transmission electrode group has a flat plate-like structure extending in the same direction. In this example, the second power transmission electrode group 120B, the first power transmission electrode group 120A, and the third power transmission electrode group 120C are arranged on a straight line in this order. The first AC output circuit 170A supplies AC energy to the first power transmission electrode group 120A and the second power transmission electrode group 120B. The second AC output circuit 170B supplies AC energy to the first power transmission electrode group 120A and the third power transmission electrode group 120C. In this case, when the control circuit transmits energy from the second power transmitting electrode group 120B to the power receiving electrode group in one moving body, the control circuit transmits the AC energy to the first AC output circuit 170A and the second power transmitting electrode group 120B. Instruct to supply. When transmitting energy from the third power transmission electrode group 120C to the power reception electrode group in another moving body, the control circuit supplies the second AC output circuit 170B with AC energy to the third power transmission electrode group 120C. Instruct.

In this example, power can be supplied to two mobile bodies from the first power transmission electrode group 120A at the same time, and power can be supplied to one mobile body from each of the second power transmission electrode group 120B and the third power transmission electrode group 120C. . The length of the chargeable region can be extended by a factor of three compared to the case where only the first power transmission electrode group 120A is arranged. In the configuration of FIG. 13B, a larger number of AC output circuits may be connected to each power transmission electrode group. According to such a configuration, it is possible to supply power to a larger number of moving bodies simultaneously. In any of the charging regions defined by the three power transmission electrode groups laid, power can be transmitted with high efficiency to a moving body that is moving or working. Despite such advantages, it is possible to appropriately reduce the cost for arranging the power supply circuit unit.

Each electrode group in the above embodiment has a structure extending in parallel in the same direction, but such a structure may not be used depending on the application. For example, each electrode may have a rectangular shape such as a square. As long as such a plurality of rectangular electrodes are arranged in one direction, the technique of the present disclosure can be applied. Further, it is not an essential requirement that the surfaces of all the electrodes are 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. Such a surface is also referred to as a “planar surface” if it is generally planar.

In the above embodiment, the power transmission electrode group 120 is laid on the ground, but the power transmission electrode group 120 may be laid on a side surface such as a wall or an upper surface such as a ceiling. The arrangement and orientation of the power receiving electrode group 220 of the moving body 10 are determined according to the location and orientation where the power transmitting electrode group 120 is laid.

FIG. 14A shows an example in which the power transmission electrode group 120 is laid on a side surface such as a wall. In this example, the power receiving electrode group 220 is disposed on the side of the moving body 10. FIG. 14B shows an example in which the power transmission electrode group 120 is laid on the ceiling. In this example, the power receiving electrode group 220 is disposed on the top plate of the moving body 10. As in these examples, there are various variations in the arrangement of the power transmission electrode group 120 and the power reception electrode group 220.

The wireless power transmission system according to the embodiment of the present disclosure can be used as a system for transporting articles in a factory as described above. The moving body 10 has a loading platform on which articles are loaded, and functions as a carriage that autonomously moves in the factory and conveys the articles to a necessary place. However, the wireless power transmission system and the moving body in the present disclosure are not limited to such applications, and can be used for various other applications. For example, the moving body is not limited to AGV, but may be other industrial machines, service robots, electric vehicles, forklifts, multicopters (drone), elevators, and the like. The wireless power transmission system is not limited to being used in a factory, and can be used in, for example, stores, 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 for a moving body such as an electric vehicle (EV), an automatic guided vehicle (AGV) used in a factory, a forklift, an unmanned aerial vehicle (UAV), or an elevator.

DESCRIPTION OF SYMBOLS 10 Mobile body 30 Floor surface 100 Power transmission apparatus 110 Inverter circuit 120 Power transmission electrode group 150 Control circuit 170 AC output circuit 180 Matching circuit 190 Switch 200 Power receiving apparatus 210 Rectifier circuit 220 Power receiving electrode group 270 DC / DC converter 280 Matching circuit 310 Power supply 330 Load

Claims (13)

1. A power transmission module used in a power transmission device in a wireless power transmission system capable of wirelessly transmitting energy via electric field from a power transmission electrode group to two or more power reception electrode groups,
   A group of power transmission electrodes including two or more power transmission electrodes;
   A first matching circuit connected between a first power conversion circuit that outputs a first AC voltage and the power transmission electrode group;
   A second matching circuit connected between the first power conversion circuit or the second power conversion circuit that outputs a second AC voltage and the power transmission electrode group;
   With
   The first and second matching circuits supply AC energy having the same phase to the power transmission electrode group.
   Power transmission module.
2. The power transmission module according to claim 1, wherein the second matching circuit is connected to the first power conversion circuit;
   The first power conversion circuit;
   A switch for switching on / off a connection between the first power conversion circuit and the second matching circuit;
   A control circuit for controlling the switch;
   A power transmission device comprising:
3. The control circuit includes:
   When one power receiving electrode group faces the power transmitting electrode group, a command to turn off the connection between the first power conversion circuit and the second matching circuit is sent to the switch,
   When two or more power receiving electrode groups face the power transmitting electrode group, a command to turn on the connection between the first power conversion circuit and the second matching circuit is sent to the switch.
   The power transmission device according to claim 2.
4. The control circuit monitors at least one of voltage, current, and power in the first matching circuit, and based on at least one value of voltage, current, and power, a power receiving electrode group facing the power transmitting electrode group The power transmission device according to claim 3, wherein the number is detected.
5. The power transmission module according to claim 1, wherein the second matching circuit is connected to the second power conversion circuit;
   The first power conversion circuit;
   The second power conversion circuit;
   A control circuit that controls the first and second power conversion circuits so as to output in-phase AC energy from the first and second matching circuits;
   A power transmission device comprising:
6. The control circuit includes:
   When one power receiving electrode group is opposed to the power transmitting electrode group, only the first power conversion circuit is driven, the operation of the second power conversion circuit is stopped,
   When two or more power receiving electrode groups are opposed to the power transmitting electrode group, both the first and second power conversion circuits are driven.
   The power transmission device according to claim 2.
7. The control circuit monitors at least one of voltage, current, and power in the first matching circuit, and based on at least one value of voltage, current, and power, a power receiving electrode group facing the power transmitting electrode group The power transmission device according to claim 6, wherein the number is detected.
8. The control circuit monitors at least one of voltage, current, and power output from each of the first and second matching circuits, and based on at least one value of the voltage, current, and power The power transmission device according to claim 5, wherein the phases of the AC energy output from the first and second matching circuits are matched by controlling the second power conversion circuit and the second power conversion circuit.
9. A power transmission device in a wireless power transmission system capable of transmitting energy wirelessly via an electric field from a power transmission electrode group to two or more power reception electrode groups,
   A group of power transmission electrodes including two or more power transmission electrodes;
   N (N is an integer of 2 or more) AC output circuits for supplying AC energy to the power transmission electrode group;
   A control circuit for controlling the N AC output circuits, wherein when transmitting energy from the power transmitting electrode group to n (n is an integer of 1 to N) power receiving electrode groups, the N AC current circuits are transmitted. A control circuit for sending a command to supply alternating current energy of the same phase to the power transmission electrode group to n AC output circuits of the output circuit;
   A power transmission device comprising:
10. The control circuit controls the N AC output circuits to supply energy of the same intensity to all of the n power receiving electrode groups that receive the energy simultaneously from the power transmitting electrode group. The power transmission device described.
11. And further comprising another power transmission electrode group including two or more power transmission electrodes,
    The N AC output circuits supply AC energy to the other power transmission electrode groups,
    When the control circuit transmits energy from the other power transmitting electrode groups to n power receiving electrode groups simultaneously (n is an integer of 1 or more and N or less), n ACs among the N AC output circuits are transmitted. The power transmission device according to claim 9 or 10, wherein a command for supplying AC energy having the same phase to the other power transmission electrode group is sent to an output circuit.
12. A second group of power transmission electrodes including two or more power transmission electrodes;
    A third power transmission electrode group including two or more power transmission electrodes;
    Further comprising
    A first AC output circuit among the N AC output circuits supplies AC energy to the second power transmission electrode group,
    A second AC output circuit of the N AC output circuits supplies AC energy to the third power transmission electrode group,
    The control circuit includes:
    When transmitting energy from the second power transmission electrode group to one power reception electrode group, a command to supply the AC energy to the second power transmission electrode group is sent to the first AC output circuit,
    When transmitting energy from the third power transmission electrode group to one other power reception electrode group, a command to supply the AC energy to the third power transmission electrode group is sent to the second AC output circuit.
    The power transmission device according to claim 10 or 11.
13. A power transmission device according to any one of claims 2 to 12,
    At least one power receiving device including a power receiving electrode group that receives power wirelessly from the power transmitting electrode group;
    A wireless power transmission system comprising:

Images