JPWO2018034196A1 - Wireless power transmission system - Google Patents

Abstract

Wireless power is transmitted by electromagnetic induction from the AC power supply circuit that supplies AC power from the AC power supply circuit of the power transmission device to the power reception coil of the power reception device that is separated by space, AC power is transmitted from the power reception coil to the load circuit, and consumed. In the wireless power transmission system, a relay electromagnetic induction circuit is provided between the AC power supply circuit and the power transmission coil or between the power reception coil and the load circuit, and the relay electromagnetic induction circuit is a primary Mutual inductance variable means for varying mutual inductance of a primary side resonance circuit including a side relay coil, a secondary side resonance circuit including a secondary side relay coil, and the primary side relay coil and the secondary side relay coil By using the wireless power transmission system having the above, when the mutual inductance of the transmitting coil and the receiving coil fluctuates, power is stably supplied to the load.

Description

  The present invention relates to a wireless power transmission system for transmitting and consuming power from a power supply circuit across a space to a load.

  Conventionally, as a non-contact power transmission device that does not use a power cord or a power transmission cable, for example, as disclosed in Patent Document 1, an AC magnetic field of a power transmission coil of a power transmission circuit and an AC magnetic field of a power receiving coil of a power receiving side resonant circuit of a power receiving circuit A wireless power transmission system has been proposed that resonates and wirelessly transmits power from a power transmission coil of a power transmission circuit to a power reception coil of a power reception circuit. In Patent Document 1, a power receiving circuit is configured by a power receiving side resonance circuit including a power receiving coil, a rectifier circuit, and a storage device, and alternating current power received by the power receiving coil of the power receiving side resonance circuit is rectified to DC power by the rectifier circuit. The storage device is being charged.

  Further, in Patent Document 2, in order to improve the impedance mismatch between the power transmission side and the power reception side due to the fluctuation of the impedance of the load of the power reception circuit, a DC voltage conversion circuit is installed between the rectifier circuit and the power storage device. Techniques for matching impedance have been proposed. In patent document 2, the conversion ratio of impedance is adjusted by changing the width | variety of the switching pulse which opens and closes the switch of the switching element of a chopper circuit, using a chopper circuit as the direct current voltage conversion circuit.

JP, 2009-106136, A International Publication No. 2010/035321

  However, in the wireless power transmission system of Patent Document 1, when the power transmission coil and the power reception coil are separated and the mutual inductance of both coils decreases, the resonance current flowing in the power reception side resonance circuit decreases and the received power received by the power reception coil from the power transmission coil is small. As a result, there has been a problem that the power receiving circuit can not receive a sufficient amount of wireless power.

  In the wireless power transmission system of Patent Document 2, since the DC voltage conversion circuit is inserted between the rectifier circuit and the storage device of the load, the conversion ratio of the impedance of the DC voltage conversion circuit is adjusted, and the load side is The impedance of the seen load can be reduced. Thus, it is considered that the Q value of the resonance of the power reception side resonance circuit can be increased to increase the resonance current of the power reception side resonance circuit, whereby the wireless power received by the power reception circuit can be increased.

  However, the DC voltage conversion circuit using the chopper circuit of Patent Document 2 has a problem that the output voltage of the chopper circuit becomes abnormal when the load resistance connected to the output terminal is large. In the chopper circuit, there is a problem that the resonance current flowing in the power receiving side resonance circuit is not stable when such a problem occurs depending on the condition of the load.

  Therefore, an object of the present invention is to provide a wireless power transmission system for stably supplying power to a load when the mutual inductance of the power transmission coil and the power reception coil fluctuates.

  In order to solve this problem, according to the present invention, wireless power is transmitted by electromagnetic induction from a power transmission coil supplying AC power from an AC power supply circuit of a power transmission apparatus to a power receiving coil of a power receiving apparatus separated by a space. A wireless power transmission system for transmitting AC power from a coil to a load circuit for consumption, comprising: a relay electromagnetic induction circuit between the AC power supply circuit and the power transmission coil or between the power receiving coil and the load circuit The relay electromagnetic induction circuit includes a primary resonance circuit including a primary relay coil, a secondary resonance circuit including a secondary relay coil, the primary relay coil, and the secondary relay. It is a wireless power transmission system characterized by having mutual inductance variable means for making the mutual inductance of coils variable.

According to this configuration, the mutual inductance varying means causes the mutual inductance of the primary side relay coil and the secondary side relay coil of the relay electromagnetic induction circuit to follow the variation in the mutual inductance of the power transmission coil and the power reception coil. By changing the voltage, it is possible to stably supply power to the load.

The present invention is also the above wireless power transmission system, wherein
The power reception device includes a power reception resonance circuit including the power reception coil, and the load circuit.
The power transmission device includes a power transmission resonance circuit including the AC power supply circuit, the relay electromagnetic induction circuit, and the power transmission coil.
The AC power supply circuit is connected to the primary side resonance circuit of the relay electromagnetic induction circuit,
The power transmission resonant circuit is connected to the secondary side resonant circuit,
The alternating current frequency of the alternating current power supply circuit, the resonance frequency of the primary side resonance circuit, and the resonance frequency of the entire secondary side resonance circuit, the power transmission resonance circuit, and the power reception resonance circuit are matched. Wireless power transmission system.

The present invention is also the above wireless power transmission system, wherein
The power transmission device includes the AC power supply circuit, and a power transmission resonant circuit including the power transmission coil.
The power reception device includes a power reception resonance circuit including the power reception coil, the relay electromagnetic induction circuit, and the load circuit.
The power reception resonance circuit is connected to the primary side resonance circuit of the relay electromagnetic induction circuit,
The load circuit is connected to the secondary side resonance circuit,
The alternating current frequency of the alternating current power supply circuit, the resonance frequency of the entire power transmission resonance circuit, the power reception resonance circuit, and the entire primary side resonance circuit are matched with the resonance frequency of the secondary side resonance circuit. Wireless power transmission system.

  According to this configuration, the mutual inductance varying means causes the mutual inductance of the primary side relay coil and the secondary side relay coil of the relay electromagnetic induction circuit to follow the variation in the mutual inductance of the power transmission coil and the power reception coil. By changing the voltage, it is possible to stably supply power to the load.

BRIEF DESCRIPTION OF THE DRAWINGS It is a circuit diagram showing the whole power transmission apparatus of the wireless power transmission system of 1st Embodiment of this invention, and a power receiving apparatus. It is a schematic plan view which shows the structure of the mutual inductance variable means by the side of the power transmission apparatus of the 1st Embodiment of this invention. It is a circuit diagram showing the whole power transmission device and power receiving device of a wireless power transmission system of a 2nd embodiment of the present invention. It is a schematic plan view which shows the structure of the mutual inductance variable means by the side of the power transmission apparatus of the 2nd Embodiment of this invention. It is a circuit diagram showing the whole power transmission device and power receiving device of a wireless power transmission system of a 4th embodiment of the present invention. It is a schematic plan view which shows the structure of the mutual inductance variable means by the side of the power transmission apparatus of the 4th Embodiment of this invention. It is a circuit diagram showing the whole power transmission apparatus and power receiving apparatus of the wireless power transmission system of the 5th Embodiment of this invention. It is a circuit diagram showing the whole power transmission device and power receiving device of a wireless power transmission system of a 6th embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

First Embodiment
A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. As in the circuit diagram of FIG. 1, the wireless power transmission system of the first embodiment includes a power transmission device 10 and a power reception device 20.

  The power transmission coil L3 of the power transmission resonance circuit 13 of the power transmission device 10 and the power reception coil L4 of the power reception resonance circuit 21 of the power reception device 20 are approached to cause electromagnetic induction with mutual inductance M to separate a space from the power transmission coil L3 to the power reception coil L4. Transmit wireless power. A load circuit 30 is connected to the power reception resonance circuit 21 of the power reception device 20, and the load circuit 30 consumes power.

(Power transmission device 10)
The power transmission device 10 includes an AC power supply circuit 11 that outputs an alternating current of a constant voltage of an output voltage E of a frequency f, a power transmission device relay electromagnetic induction circuit 12 that resonates at the frequency f, and a power transmission resonance circuit 13.

(AC power supply circuit 11)
The AC power supply circuit 11 of the power transmission device 10 supplies an output current i1 of frequency f at a constant voltage. The primary side resonance circuit of the power transmission device relay electromagnetic induction circuit 12 is connected in series to the AC power supply circuit 11, and an output current i1 flows.

(Relay electromagnetic induction circuit 12 for power transmission equipment)
The power transmission device relay electromagnetic induction circuit 12 of the power transmission device 10 includes a primary side resonance circuit including the primary side relay coil L1, a secondary side resonance circuit including the secondary side relay coil L2, and a primary side relay coil L1. And a power transmission apparatus mutual inductance variable means 12a for making the mutual inductance M1 of the secondary side relay coil L2 variable.

  The primary side resonance circuit is composed of a primary side resonance capacitor C1 and a primary side relay coil L1, and the secondary side resonance circuit is composed of a secondary side resonance capacitor C2 and a secondary side relay coil L2. The primary side relay coil L1 of the primary side resonant circuit and the secondary side relay coil L2 of the secondary side resonant circuit are electromagnetically induced by the mutual inductance M1. Each of the primary side resonant circuit and the secondary side resonant circuit resonates at the frequency f of the AC power supply circuit 11.

  The AC power supply circuit 11 is connected in series to the primary side resonance circuit to flow the output current i1 of the AC power supply circuit 11, and the power transmission resonance circuit 13 is connected in series to the secondary side resonance circuit to flow the resonance current i2.

  Here, the secondary relay coil L2 and the secondary resonance capacitor C2 of the relay electromagnetic induction circuit 12 for power transmission device are connected in series to the power transmission resonance capacitor C3 of the power transmission resonant circuit 13 and the power transmission coil L3, and The whole is resonated at the frequency f of the AC power of the AC power supply circuit 11.

(Mutual inductance variable means 12a for power transmission equipment)
The mutual inductance M1 of the electromagnetic induction of the primary side relay coil L1 and the secondary side relay coil L2 is made variable using the power transmission device mutual inductance variable means 12a. The power transmission device mutual inductance varying means 12a mechanically moves the primary side relay coil L1 or the secondary side relay coil coil L2 of the power transmission device relay electromagnetic induction circuit 12 to generate the primary side relay coil L1 and the secondary side. The mutual inductance M1 can be changed by changing the relative position of the relay coil L2.

  For example, the mutual inductance variable means 12a for a power transmission apparatus can be used to freely change the distance between the primary relay coil L1 and the secondary relay coil L2, or as shown in the plan view of FIG. The mutual inductance M1 between the two coils can be freely adjusted by using the mutual inductance variable means 12a for the power transmission device which freely shifts the axis of L1 and the secondary side relay coil L2.

(Transmission resonance circuit 13)
The power transmission resonance circuit 13 of the power transmission device 10 is connected in series to the secondary side resonance circuit of the power transmission device relay electromagnetic induction circuit 12. The power transmission resonance circuit 13 includes a power transmission resonance capacitor C3 and a power transmission coil L3. The entire circuit consisting of the power transmission resonant circuit 13 and the secondary side resonant circuit connected in series is resonated at the same resonant frequency f as the resonant frequency f of the primary side resonant circuit to flow a resonant current i2.

(Power receiving device 20)
The power reception device 20 is configured by connecting a load circuit 30 in series to the power reception resonance circuit 21. The power reception resonance circuit 21 is configured by connecting in series a power reception coil L4 that performs electromagnetic induction on the power transmission coil L3 of the power transmission resonance circuit 13 and a power reception resonance capacitor C4. The power reception resonance circuit 21 is caused to resonate at the same resonance frequency f as the power transmission resonance circuit 13 to flow the resonance current i3 and flow it into the load circuit 30.

(Load circuit 30)
The load circuit 30 includes a rectifier circuit 31 connected to the power reception resonance circuit 21, a power storage device 32, and a load 33. The rectification circuit 31 rectifies the resonance current i3 of the power reception resonance circuit 21 into a direct current. The direct current power output from the rectifier circuit 31 is stored in the storage device 32 formed of a capacitor or a secondary battery and consumed by the load 33 such as a light emitting element or a motor.

(Secondary resonance current limiting function of relay electromagnetic induction circuit 12 for power transmission equipment)
Assuming that the output voltage of the AC power supply circuit 11 is E and the angular frequency of the resonance frequency f is ω, when the secondary side relay coil L2 is electromagnetically coupled to the primary side relay coil L1 by mutual inductance M1, secondary The resonance current i2 flowing through the side relay coil L2 and the power transmission coil L3 of the power transmission resonance circuit 13 can be calculated by the following equation 1.
(Formula 1) i2 = E / (jωM1)

  In Equation 1, the resonance current i2 flowing through the secondary relay coil L2 and the power transmission coil L3 is not influenced by the power receiving device 20, and only the mutual inductance M1 of the primary relay coil L1 and the secondary relay coil L2 is It means that it is inversely proportional.

  By fixing the mutual inductance variable means 12a for the power transmission device of the relay electromagnetic induction circuit 12 for the power transmission device connected to the AC power supply circuit 11 of constant voltage according to this equation 1, the primary side relay coil L1 and the secondary side relay coil L2 When the mutual inductance M1 is made constant, the resonance current i2 flowing through the secondary side resonance circuit and the power transmission resonance circuit 13 is maintained at a constant value, and there is a secondary side resonance current limiting effect. That is, the relay electromagnetic induction circuit 12 for power transmission device connected to the AC power supply circuit 11 of constant voltage is not influenced by the mutual inductance M of the power transmission coil L3 and the power reception coil L4, and the resonant current i2 to flow through the power transmission coil L3 is constant value Can be limited to

  The secondary relay coil L2 and the power transmission resonance circuit 13 can be obtained by changing the number of turns of the primary relay coil L1 and the number of turns of the secondary relay coil L2 in the power transmission device relay electromagnetic induction circuit 12. The resonant current i2 flowing to the power transmission coil L3 can be changed. For example, when the number of turns of the secondary relay coil L2 is halved with respect to the number of turns of the primary relay coil L1 of the power transmission device relay electromagnetic induction circuit 12, the output of the resonance current i2 The ratio to the voltage E can be doubled.

The resonance current i3 flowing through the load circuit 30 of the power reception device 20 affects the output current i1 of the AC power supply circuit 11 according to the following equation (2).
(Expression 2) i1 = (M / M1) i3

  Expression 2 means that when the resonance current i3 flows in the load circuit 30, the output current i1 represented by Expression 2 flows out from the AC power supply circuit 11. That means that the image impedance at the position of the output terminal of the AC power supply circuit 11 is a square multiple of (M1 / M) of the input impedance of the load circuit 30. Therefore, when the mutual inductance M of the power transmission coil L3 and the power reception coil L4 decreases, the image impedance increases, which means that the output current i1 of the AC power supply circuit 11 decreases.

  Conventionally, in a circuit in which the power transmission resonance circuit 13 is connected in series to the AC power supply circuit 11 of constant voltage, the output current i1 of the AC power supply circuit 11 flows to the power transmission coil L3 of the power transmission resonance circuit 13 and the resonance current i2 of the power transmission coil L3 Although the output current i1 is large, when the distance between the power transmission coil L3 and the power reception coil L4 increases and the mutual inductance M decreases, there is a problem that the resonance current i2 and the output current i1 increase infinitely.

  In the present invention, this problem is solved by installing the relay electromagnetic induction circuit 12 for power transmission between the AC power supply circuit 11 of constant voltage and the power transmission resonance circuit 13, and the resonance flowing in the power transmission coil L 3 of the power transmission resonance circuit 13. The current i2 can be limited to a constant value.

  Here, using the relay electromagnetic induction circuit 12 for a power transmission device having a secondary side resonance circuit having the same resonance frequency f as the resonance frequency f of the power transmission resonance circuit 13 and a primary side resonance circuit, an AC power supply circuit of the resonance frequency f It is important to connect 11 in series to the primary side resonant circuit.

  When the alternating current frequency of the alternating current power supply circuit 11 deviates from the resonant frequency f of the power transmission resonant circuit 13 and the relay electromagnetic induction circuit 12 for power transmission device, an infinitely large resonant current i2 flows in the power transmission coil L3 of the power transmission resonant circuit 13 Can occur.

  Therefore, it is desirable to provide a frequency stabilization circuit that makes the frequency of the AC power supply circuit 11 always coincide with the resonant frequency f of the power transmission resonant circuit 13 and the relay electromagnetic induction circuit 12 for power transmission device. Also, when the frequency of the AC power supply circuit 11 deviates from the resonant frequency f of the power transmission resonance circuit 13 and the relay electromagnetic induction circuit 12 for power transmission device, the connection on the way from the AC power supply circuit 11 to the power transmission coil L3 is disconnected It is desirable to provide a circuit.

(Voltage E4 applied to load circuit 30)
Since the resonance current i2 flowing through the power transmission coil L3 is expressed by the formula 1, an induced electromotive force E4 expressed by the following formula 3 is generated in the power receiving coil L4 electromagnetically induced by the mutual inductance M in the power transmission coil L3. The induced electromotive force E4 is applied to the load circuit 30.
(Equation 3) E4 = jωM × i2 = (M / M1) E
Equation 3 indicates that the induced electromotive force E4 induced in the power receiving coil L4 applied to the load circuit 30 is (M / M1) times the output voltage E of the AC power supply circuit 11.

(Output power stabilization control means 40)
The output power stabilization control unit 40 includes a power supply current measurement unit 41 that measures the output current i 1 of the constant voltage AC power supply circuit 11 and an output power control calculation unit 42. The output power control calculation means 42 of the output power stabilization control means 40 operates the power transmission device mutual inductance variable means 12a so that the output current i1 of the AC power supply circuit 11 measured by the power supply current measurement means 41 has a constant value. By performing control, the supply of power to the load circuit 30 can be stabilized.

  When the distance between the power transmission coil L3 of the power transmission device 10 and the power reception coil L4 of the power reception device 20 changes, the mutual inductance M of the electromagnetic induction of the power transmission coil L3 and the power reception coil L4 changes. In that case, the power supply current measurement unit 41 of the output power stabilization control unit 40 measures the fluctuation of the output current i1 of the AC power supply circuit 11, and operates the power transmission device mutual inductance variable unit 12a based on the measurement result. The mutual inductance M1 of the primary side relay coil L1 and the secondary side relay coil L2 is varied in proportion to the mutual inductance M.

  By the control, the induced electromotive force E4 induced to the power receiving coil L4 of the power receiving resonant circuit 21 is maintained at a constant value according to the equation 3, and the induced electromotive force E4 is added to the load circuit 30 to stabilize the load circuit 30. The constant power can be supplied, and the resonance current i3 flowing to the load circuit 30 can also be stabilized. At that time, the output current i1 of the AC power supply circuit 11 can also be stabilized in accordance with Equation 2.

  Further, when the power receiving device 20 is not near the power transmission device 10, the output power control calculation means 42 searches for the power receiving coil L4 of the power receiving device 20 using the power supply current measurement means 41. That is, the power supply current measurement means 41 measures an increase in the output current i1 of the AC power supply circuit 11, thereby detecting the approach of the power receiving coil L4 to the power transmitting coil L3. Here, in order to increase the sensitivity of detection of the power receiving coil L4, the output power control calculation means 42 intermittently reduces the mutual inductance M1 to cause the current i2 to flow through the power transmission coil L3 and the output current i1 of the AC power supply circuit 11 Control to increase.

Second Embodiment
A second embodiment of the present invention will be described with reference to FIGS. 3 and 4. The second embodiment includes the power transmission device 10 and the power reception device 20 as in the first embodiment. The second embodiment is different from the first embodiment in that the power transmission resonant circuit 13 doubles as the secondary side resonance circuit of the power transmission device relay electromagnetic induction circuit 12 as shown in the circuit diagram of FIG. It is.

  That is, the power transmission coil L3 of the power transmission resonance circuit 13 includes the secondary relay coil L2 of the power transmission device relay electromagnetic induction circuit 12, and the power transmission resonance capacity C3 of the power transmission resonance circuit 13 is the power transmission device relay electromagnetic induction circuit 12. The secondary side resonance capacitor C2 is included. The power transmission resonance circuit 13 configured by the power transmission coil L3 and the power transmission resonance capacitor C3 resonates at the frequency f of the AC power supply circuit 11.

(Relay electromagnetic induction circuit 12 for power transmission equipment)
The power transmission device relay electromagnetic induction circuit 12 of the power transmission device 10 has a primary side resonance circuit connected in series to the AC power supply circuit 11. The primary side resonance circuit is configured of a primary side resonance capacitor C1 and a primary side relay coil L1, and resonates at the frequency f of the AC power supply circuit 11. The primary side relay coil L1 of the power transmission device relay electromagnetic induction circuit 12 electromagnetically induces the power transmission coil L3 of the power transmission resonance circuit 13 with the mutual inductance M1. In the power transmission coil L3 of the power transmission resonance circuit 13, the power reception coil L4 of the power reception resonance circuit 21 further induces electromagnetic induction with the mutual inductance M.

(Mutual inductance variable means 12a for power transmission equipment)
The power transmission device mutual inductance variable means 12a freely changes the overlapping area of the primary side relay coil L1 of the power transmission device relay electromagnetic induction circuit 12 and the power transmission coil L3 of the power transmission resonance circuit 13 as shown in the plan view of FIG. By using the power transmission device mutual inductance variable means 12a, the mutual inductance M1 between both coils can be adjusted freely. In addition, the mutual inductance variable means 12a for the power transmission device is configured to freely change the interval in which the primary side relay coil L1 of the power transmission device relay electromagnetic induction circuit 12 and the power transmission coil L3 of the power transmission resonance circuit 13 are opposed. The inductance variable means 12a can also be used.

Third Embodiment
Similar to the first embodiment, the third embodiment includes the power transmission device 10 and the power reception device 20, and the power transmission device 10 has the power transmission device relay electromagnetic induction circuit 12. Here, the power transmission coil L3 of the power transmission resonance circuit 13 of the power transmission device 10 and the power reception coil L4 of the power reception resonance circuit 21 of the power reception device 20 are coupled by mutual inductance M to form an integrated circuit and resonate, and the resonant frequency of the integrated circuit Has a resonance frequency different from the resonance frequency of the power transmission resonance circuit 13 alone or the resonance frequency of the power reception resonance circuit 21 alone.

  The third embodiment is different from the first and second embodiments in that the resonant frequency of the integrated circuit in which the power transmission coil L3 of the power transmission resonant circuit 13 and the power receiving coil L4 of the power receiving resonant circuit 21 are electromagnetically coupled The point is that power is transmitted by making the resonance frequency of the device relay electromagnetic induction circuit 12 and the frequency f of the AC power supply circuit 11 the same. Further, the resonant frequency of the power transmission resonant circuit 13 alone and the resonant frequency of the power reception resonant circuit 21 alone are different from the frequency f of the AC power supply circuit 11 from the first and second embodiments.

(Secondary resonance current limit function)
Also in the third embodiment, the primary relay coil L1 and the secondary side are fixed by fixing the mutual inductance variable means 12a for the power transmission device relay electromagnetic induction circuit 12 connected to the constant voltage AC power supply circuit 11. When the mutual inductance M1 of the relay coil L2 is made constant, the resonance current i2 flowing through the power transmission coil L3 of the secondary side resonance circuit and the power transmission resonance circuit 13 is maintained at a constant value expressed by Equation 1 effective. In the third embodiment, there is an effect that the resonance current i3 flowing through the power receiving coil L4 is maintained at a constant value similar to that of the resonance current i2 by linking to the resonance current i2 flowing through the power transmission coil L3 of the integrated circuit.

  The ratio of the resonant current i3 flowing through the power receiving coil L4 to the resonant current i2 flowing through the power transmitting coil L3 is a constant value related to the self inductance of the power transmitting coil L3 and the power receiving coil L4. Therefore, in the third embodiment, in order to make the value of the resonance current i3 constant, the power transmission device mutual inductance variable means 12a is fixed and the primary side relay coils L1 and L2 of the power transmission device relay electromagnetic induction circuit 12 are fixed. It is only necessary to set the mutual inductance M1 of the next relay coil L2 to a constant value.

Fourth Embodiment
A fourth embodiment of the present invention will be described with reference to FIGS. 5 and 6. The fourth embodiment differs from the above embodiments in that the secondary resonance circuits of the power transmission resonant circuit 13 and the relay electromagnetic induction circuit 12 for power transmission device are connected in parallel via a resonance capacitor. . That is, a circuit in which the resonance capacitor C5 and the power transmission coil L3 are connected in parallel to the secondary relay coil L2 of the power transmission device relay electromagnetic induction circuit 12 is configured to resonate at the frequency f of the AC power supply circuit 11.

  The fourth embodiment includes the power transmission device 10 and the power reception device 20 as in the first embodiment. The power transmission device 10 includes an AC power supply circuit 11 of frequency f, a power transmission device relay electromagnetic induction circuit 12 resonating at the frequency f, and a power transmission resonance circuit 13. The receiving coil L4 of the power receiving device 20 is electromagnetically induced by the mutual inductance M to the power transmission coil L3 of the power transmission resonance circuit 13 and the AC power supplied by the AC power supply circuit 11 up to the power receiving coil L4 separated from the power transmission coil L3 Transmit power wirelessly. A load circuit 30 is connected to the power reception resonance circuit 21 of the power reception device 20, and the load circuit 30 consumes power.

(Relay electromagnetic induction circuit 12 for power transmission equipment)
The AC power supply circuit 11 of the power transmission device 10 is connected in series to the primary side resonance circuit of the power transmission device relay electromagnetic induction circuit 12 to flow the output current i1 of the AC power supply circuit 11.

  By connecting the secondary relay coil L2 of the relay electromagnetic induction circuit 12 for power transmission device to the resonance capacitance C5 and connecting the power transmission coil L3 of the power transmission resonance circuit 13 in parallel to the resonance capacitance C5, the resonance capacitance C5 Are shared by the secondary side resonance circuit and the power transmission resonance circuit 13 of the power transmission device relay electromagnetic induction circuit 12. The primary side relay coil L1 and the secondary side relay coil L2 of the primary side resonance circuit of the power transmission device relay electromagnetic induction circuit 12 are electromagnetically induced by the mutual inductance M1. The primary side resonance circuit, the secondary side resonance circuit, and the power transmission resonance circuit 13 are resonated at the frequency f of the output current i1 of the AC power supply circuit 11.

(Mutual inductance variable means 12a for power transmission equipment)
By changing the relative position of the primary relay coil L1 and the secondary relay coil L2 using the power transmission device mutual inductance variable means 12a as shown in the plan view of FIG. 6, the primary relay coil L1 is made variable. And the mutual inductance M1 of the electromagnetic induction of the secondary side relay coil L2 is made variable.

(Current limit function)
The AC power supply circuit 11 is connected in series to the primary side resonance circuit to flow the output current i1 of the AC power supply circuit 11. The secondary relay coil L2 of the secondary resonance circuit and the power transmission coil L3 of the power transmission resonance circuit 13 are connected in parallel to the resonance capacitor C5. A resonant current i2 flows in the secondary relay coil L2. A resonant current i4 flows in the power transmission coil L3 of the power transmission resonant circuit 13. At this time, the resonance current i2 flowing through the secondary relay coil L2 can be calculated by Equation 1.

When the secondary relay coil L2 and the power transmission coil L3 are connected in parallel to the resonance capacitor C5, and the primary relay coil L1 and the secondary relay coil L2 are electromagnetically coupled by mutual inductance M1, circuit simulation shows As a result of analyzing the voltage E5 of the power transmission coil L3, the following equation 4 approximately obtained was obtained.
(Equation 4) E5 = E / k1
That is, the voltage E5 of the power transmission coil L3 becomes a value obtained by dividing the output voltage E of the AC power supply circuit 11 by the coupling coefficient k1 = (M1 / L2).

The following approximate equation 5 was obtained for the resonance current i4 flowing through the power transmission coil L3.
(Formula 5) i4 = E5 / (jωL3) = E / (jωL3 × k1)

  Similarly to the first embodiment, in the fourth embodiment, the power transmission device variable inductance means 12a of the power transmission device relay electromagnetic induction circuit 12 connected to the constant voltage AC power supply circuit 11 is fixed to the primary side. When the mutual inductance M1 of the relay coil L1 and the secondary side relay coil L2 is made constant, there is a current limiting effect of limiting the resonance current i4 flowing through the power transmission coil L3 to the value or less of Formula 5. That is, the relay electromagnetic induction circuit 12 for power transmission device connected to the AC power supply circuit 11 of constant voltage is not influenced by the mutual inductance M of the power transmission coil L3 and the power reception coil L4, and the resonant current i4 to flow through the power transmission coil L3 is constant value It can be limited to:

(Power receiving device 20, etc.)
The power reception device 20 of the fourth embodiment and the output power stabilization control means 40 of the power transmission device 10 are configured in the same manner as in the first embodiment.

Since the resonance current i2 flowing through the power transmission coil L3 is expressed by the equation 5, the induced electromotive force E4 generated in the power receiving coil L4 having the mutual inductance M with the power transmission coil L3 is expressed by the following approximate expression 6, The induced electromotive force E4 is applied to the load circuit 30.
(Equation 6) E4 = jωM × i4 = (k / k1) E

  Equation 6 shows that the induced electromotive force E4 applied to the load circuit 30 is the coupling coefficient k = (M / L3) of the power transmission coil L3 and the power reception coil L4 with the primary side relay coil L1 of the power transmission device relay electromagnetic induction circuit 12 It means that it is proportional to the value divided by the coupling coefficient k1 = (M1 / L2) of the secondary side relay coil L2.

On the other hand, the output current i1 of the AC power supply circuit 11 is expressed by the following equation 7 with respect to the resonance current i3 flowing through the load circuit 30 and the power receiving coil L4.
(Equation 7) i1 = (k / k1) i3

  Expression 7 means that when the resonance current i3 flows in the load circuit 30, the output current i1 represented by Expression 7 flows out of the AC power supply circuit 11. That means that the image impedance at the position of the output terminal of the AC power supply circuit 11 is a square multiple of (k1 / k) of the input impedance of the load circuit 30. Therefore, when the coupling coefficient k (or mutual inductance M) of the power transmission coil L3 and the power reception coil L4 decreases, the image impedance at the position of the output terminal of the AC power circuit 11 increases and the output current i1 of the AC power circuit 11 decreases. It means to become.

  When the distance between the power transmission coil L3 of the power transmission device 10 and the power reception coil L4 of the power reception device 20 fluctuates and the mutual inductance M of the power transmission coil L3 and power reception coil L4 fluctuates, the power supply current measurement of the output power stabilization control means 40 The means 41 detects the output current i1 of the AC power supply circuit 11 to detect the fluctuation.

  Then, the output power control calculation means 42 controls the power transmission device mutual inductance variable means 12a of the power transmission device relay electromagnetic induction circuit 12 to make the mutual inductance M1 of the primary side relay coil L1 and the secondary side relay coil L2 mutual. Change in proportion to the inductance M. By this control, the induced electromotive force E4 induced to the power receiving coil L4 of the power receiving resonant circuit 21 can be maintained at a constant value and added to the load circuit 30, and there is an effect that stable power supply to the load circuit 30 can be performed.

Fifth Embodiment
A fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is different from the above embodiments in that the power reception device relay electromagnetic induction circuit 22 is installed between the power reception resonance circuit 21 of the power reception device 20 and the load circuit 30.

  In the fifth embodiment, as in the first embodiment, the power transmission coil L3 of the power transmission device 10 and the power reception coil L4 of the power reception resonance circuit 21 of the power reception device 20 are electromagnetically induced by mutual inductance M The wireless power is transmitted to the power receiving coil L4 separated from the space.

(Power transmission device 10)
As the power transmission device 10 of the fifth embodiment, the conventional power transmission device 10 without the power transmission device relay electromagnetic induction circuit 12 can be used. Alternatively, for the power transmission device 10, the power transmission device of any of the circuits of the first to fourth embodiments of the present invention can be used. A resonant current i5 is supplied to the power transmission coil L3 of the power transmission device 10.

(Power receiving device 20)
The power reception device 20 installs the power reception device relay electromagnetic induction circuit 22 between the load circuit 30 and the power reception resonance circuit 21 configured by the power reception coil L4 and the power reception resonance capacitance C4.

(Relay electromagnetic induction circuit 22 for power receiving device)
The power receiving device relay electromagnetic induction circuit 22 of the power receiving device 20 includes a primary side resonance circuit including a primary side relay coil L6, a secondary side resonance circuit including a secondary side relay coil L7, and a primary side relay coil L6. And a mutual inductance variable means 22a for power reception device which makes the mutual inductance M2 of the secondary side relay coil L7 variable.

  The primary side resonance circuit is composed of a primary side resonance capacitor C6 and a primary side relay coil L6, and the secondary side resonance circuit is composed of a secondary side resonance capacitor C7 and a secondary side relay coil L7. The primary side relay coil L6 of the primary side resonant circuit and the secondary side relay coil L7 of the secondary side resonant circuit are electromagnetically induced by the mutual inductance M2.

  In this embodiment, the primary side resonance circuit is connected in series to the power reception resonance circuit 21, and the resonance current i3 of the power reception resonance circuit 21 is supplied to the primary side resonance circuit, and the secondary side resonance circuit and the load connected in series thereto. A resonant current i6 is supplied to the circuit 30.

  The power reception resonance circuit 21 connected in series and the entire primary side resonance circuit resonate at a resonance frequency f. The resonance frequency f is made to coincide with the resonance frequency f of the secondary side resonance circuit. In addition, an alternating current of the frequency f is supplied to the power transmission coil L3 of the power transmission device 10.

(Mutual inductance variable means 22 a for power receiving device)
The mutual inductance M2 of the electromagnetic induction of the primary side relay coil L6 and the secondary side relay coil L7 is made variable by using the power receiving device mutual inductance changing means 22a, and can be freely adjusted. The power receiving device mutual inductance changing means 22a is configured in the same manner as the power transmitting device mutual inductance changing means 12a of the first embodiment, and the primary side relay coil L6 or the secondary side of the power receiving device relay electromagnetic induction circuit 22. It is possible to use means for mechanically moving the relay coil L7 to change the relative position of the primary relay coil L6 and the secondary relay coil L7 to change the mutual inductance M2.

(Load circuit 30)
A load circuit 30 is connected in series to the secondary side resonance circuit of the power receiving device relay electromagnetic induction circuit 22, and power is consumed by the load circuit 30. The load circuit 30 includes a rectifier circuit 31 connected to the secondary side resonance circuit, a power storage device 32, and a load 33. The rectifier circuit 31 rectifies the resonance current i6 of the secondary side resonance circuit into a direct current. The direct current power output from the rectifier circuit 31 is stored in the storage device 32 formed of a capacitor or a secondary battery and consumed by the load 33 such as a light emitting element or a motor. The resonance current i6 to be supplied to the load circuit 30 can be varied by adjusting the power receiving device mutual inductance varying means 22a.

(Secondary resonance current adjustment function)
In the circuit simulation, the secondary relay coil L7 and the series thereof are adjusted in the case of adjusting the mutual inductance M2 of the electromagnetic induction of the primary relay coil L6 and the secondary relay coil L7 using the power receiving device mutual inductance varying means 22a. As a result of analyzing the resonance current i6 flowing through the load circuit 30 connected to the circuit, there is a relation of the following approximate expression 8.
(Expression 8) i6 = (M / M2) i5

  This equation 8 means that, when the resonance current i5 of the power transmission coil L3 is constant, the current of the value of equation 8 flows without being influenced by the input impedance of the load circuit 30, the resonance current i6 flowing through the load circuit 30. Do. The resonance current i6 is inversely proportional to the mutual inductance M2 of the primary side relay coil L6 and the secondary side relay coil L7 of the power receiving device relay electromagnetic induction circuit 22.

  Here, when the input impedance of the load circuit 30 is large, the voltage E4 applied to the load circuit 30 becomes large. In that case, the resonance current i3 flowing through the power receiving coil L4 is increased. The large resonance current i3 flows to the primary relay coil L6 to cause electromagnetic induction, thereby inducing a large induced electromotive force E4 to the secondary relay coil L7, and the induced electromotive force E4 is added to the load circuit 30.

  On the other hand, the power received by the receiving coil L4 from the transmitting coil L3 is a product of the induced electromotive force generated in the receiving coil L4 by electromagnetic induction from the transmitting coil L3 and the resonant current i3 flowing in the receiving coil L4, and becomes large power . Therefore, when the input impedance of the load circuit 30 is large, large power is transmitted from the power transmission coil L3 to the load circuit 30 via the power receiving coil L4, the primary relay coil L6, and the secondary relay coil L7 for consumption. Be done.

  When the mutual inductance M2 of the primary side relay coil L6 and the secondary side relay coil L7 of the power receiving device relay electromagnetic induction circuit 22 is fixed to a fixed value, the mutual inductance M of the power transmitting coil L3 and the power receiving coil L4 decreases. The resonance current i6 flowing through the secondary relay coil L7 decreases. By changing the mutual inductance M2 of the power reception device relay electromagnetic induction circuit 22 in proportion to the mutual inductance M of the power transmission coil L3 and the power reception coil L4 using the power reception device mutual inductance variable means 22a, the secondary side relay coil L7 Can be stabilized to a constant value.

(Received power stabilization control means 50)
The received power stabilization control means 50 includes a load current measuring means 51 for measuring the resonance current i6 flowing in the load circuit 30 or the current flowing in the load 33, and the received power control calculation means 52. The received power control calculation means 52 of the received power stabilization control means 50 controls the power receiving device mutual inductance varying means 22a so as to make the current value measured by the load current measuring means 51 a constant value, and the power from the power transmission coil L3. Stably receive power.

When the distance between the power transmission coil L3 of the power transmission device 10 and the power reception coil L4 of the power reception device 20 changes, the mutual inductance M of the electromagnetic induction of the power transmission coil L3 and the power reception coil L4 changes. In that case, the load current measurement means 51 of the received power stabilization control means 50 measures the fluctuation of the resonant current i6 flowing in the load circuit 30, and operates the power reception device mutual inductance variable means 22a based on the measurement result. The mutual inductance M2 of the primary side relay coil L6 and the secondary side relay coil L7 is varied in proportion to the mutual inductance M. By the control, there is an effect that the resonance current i6 to be flowed into the load circuit 30 can be stabilized at a constant level.

  Also, when the power receiving device 20 approaches the power transmission device 10 from a position away from the power transmission device 10, the received power control calculation unit 52 searches for the power transmission coil L3 of the power transmission device 10 using the load current measurement device 51. . That is, the load current measurement unit 51 measures an increase in the resonance current i6 flowing through the load circuit 30, thereby detecting the approach of the power receiving coil L4 to the power transmitting coil L3. Here, in order to increase the detection sensitivity of the power transmission coil L3, the received power control calculation means 52 performs control to intermittently decrease the mutual inductance M2 and increase the resonance current i6 flowing through the load circuit 30.

  When the power transmission device 10 includes the output power stabilization control unit 40 as in the first embodiment, the output power stabilization control unit 40 of the power transmission device 10 and the received power stabilization of the power reception device 20 are provided. The control means 50 will compete. In that case, since the output power stabilization control means 40 of the power transmission device 10 and the received power stabilization control means 50 of the power reception device 20 wirelessly communicate, the transmission of wireless power is stabilized using either of the power stabilization control means It is desirable to determine and control whether to

(Modification 1)
Like the power transmission resonant circuit 13 of the second embodiment, the power reception resonant circuit 21 of the fifth embodiment is a circuit in which the power reception resonant circuit 21 doubles as the primary side resonance circuit of the power receiving device relay electromagnetic induction circuit 22. Can be configured. That is, the receiving coil L4 of the power receiving resonance circuit 21 includes the primary side relay coil L6 of the power receiving device relay electromagnetic induction circuit 22, and the power receiving resonance capacitance C4 of the power receiving resonance circuit 21 includes the power transmission device relay electromagnetic induction circuit. The twelve primary side resonance capacitors C6 can be included. By resonating the power reception coil L4 and the power reception resonance capacitance C4 of the power reception resonance circuit 21 at the frequency f of the AC power supply circuit 11, the power reception coil separated from the power transmission coil L3 from the AC power supply circuit 11 is similarly to the above. Power can be transmitted to the load circuit 30 via the coil L4.

Sixth Embodiment
A sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, as in the fifth embodiment, the resonance current i5 is supplied to the power transmission coil L3 and the relay electromagnetic induction circuit 22 for power reception is interposed between the power reception resonance circuit 21 of the power reception device 20 and the load circuit 30. Install. The sixth embodiment differs from the fifth embodiment in that the primary side resonance circuits of the power reception resonance circuit 21 and the relay electromagnetic induction circuit 22 for power reception device are connected in parallel via a resonance capacitor. is there. That is, by making the circuit in which the resonance capacitor C8 and the primary relay coil L6 of the relay electromagnetic induction circuit 22 for the power receiving device are connected in parallel to the power receiving coil L4, the power reception resonance circuit 21 and the primary side resonance circuit are resonant capacitors. Connected in parallel via C8, the entire circuit is resonated at the frequency f of the AC power supply circuit 11.

  That is, by connecting the power receiving coil L4 of the power receiving resonance circuit 21 and the primary side relay coil L6 of the primary side resonance circuit of the power receiving apparatus relay electromagnetic induction circuit 22 in parallel to the resonance capacity C8, the resonance capacity C8 is shared by the primary resonance circuit of the power reception resonance circuit 21 and the relay electromagnetic induction circuit 22 for power reception device.

  A resonant current i3 is supplied to the power receiving coil L4 connected in parallel to the resonant capacitor C8, and a resonant current i7 is supplied to the primary relay coil L6. In the power receiving apparatus relay electromagnetic induction circuit 22, the primary side relay coil L6 and the secondary side relay coil L7 are electromagnetically induced by the mutual inductance M2. The load circuit 30 is connected in series to the secondary side relay coil L7 of the secondary side resonant circuit, and a resonance current i6 flows. Then, the power reception resonance circuit 21, the primary side resonance circuit, and the secondary side resonance circuit are resonated at the frequency f of the AC power supply circuit 11.

In the circuit simulation, the secondary relay coil L7 and the series thereof are adjusted in the case of adjusting the mutual inductance M2 of the electromagnetic induction of the primary relay coil L6 and the secondary relay coil L7 using the power receiving device mutual inductance varying means 22a. As a result of analyzing the resonance current i6 flowing through the load circuit 30 connected to the circuit, there is a relation of the following approximate expression 9.
(Equation 9) i6 = (M / M2) (L6 / L4) i5 = (k / k2) i5

  This equation 9 means that when the resonance current i5 of the power transmission coil L3 is constant, the current of the value of equation 9 flows without being influenced by the input impedance of the load circuit 30, the resonance current i6 flowing through the load circuit 30. Do. The resonant current i6 is inversely proportional to the coupling coefficient k2 = (M2 / L6) of the primary side relay coil L6 and the secondary side relay coil L7 of the power receiving device relay electromagnetic induction circuit 22.

  When the mutual inductance M2 and coupling coefficient k2 of the electromagnetic induction of the primary side relay coil L6 and the secondary side relay coil L7 of the relay electromagnetic induction circuit 22 for power reception device are fixed to a fixed value, the power transmission coil L3 and the power reception coil L4 As the mutual inductance M decreases, the resonance current i6 flowing through the secondary relay coil L7 decreases. By changing the mutual inductance M2 of the power reception device relay electromagnetic induction circuit 22 following the mutual inductance M of the power transmission coil L3 and the power reception coil L4 using the power reception device mutual inductance variable means 22a, the secondary side relay The resonant current i6 flowing through the coil L7 can be stabilized to a constant value.

Example 1
In the circuit configuration of the fifth embodiment of the present invention, in the circuit simulation, the power transmission coil L3 of the power transmission device 10 is 1.1 μH, and the power transmission coil L3 has a resonant current i5 with a frequency f of 1.7 MHz and an amplitude of 1 A. Flowed out. The receiving coil L4 and the primary relay coil L6 and the secondary relay coil L7 of the power receiving apparatus 20 are 1.1 μH, and the receiving resonance capacitor C4, the primary resonance capacitor C6 and the secondary resonance capacitor C7 are 8 nF. I made it. The mutual inductance M of the power transmission coil L3 and the power reception coil L4 and the mutual inductance M2 of the primary relay coil L6 and the secondary relay coil L7 were set to 0.1 μH.

Here, as a result of performing circuit simulation by changing the input impedance of the load circuit 30 from 1Ω to 32Ω, the amplitude of the resonance current i6 flowing through the load circuit 30 is as shown in Table 1 below.
(Table 1)
Input impedance of load circuit 30, amplitude of resonant current i6 1Ω 1A
2Ω 1A
4Ω 0.9A
8Ω 0.8A
16 Ω 0.6 A
32 Ω 0.35 A

  That is, when the input impedance of the load circuit 30 is 2 Ω or less, the amplitude of the resonance current i6 becomes 1 A according to the equation 8. When the input impedance of the load circuit 30 becomes larger than that, the resonance current i6 becomes smaller.

(Example 2)
In the circuit configuration of the fifth embodiment of the present invention, in the circuit simulation, the power transmission coil L3 of the power transmission device 10 is 2.2 μH, and the power transmission coil L3 has a resonant current i5 with a frequency f of 1.7 MHz and an amplitude of 1 A. Flowed out. The receiving coil L4 and the primary relay coil L6 and the secondary relay coil L7 of the power receiving apparatus 20 are 2.2 μH, and the receiving resonance capacitor C4, the primary resonance capacitor C6 and the secondary resonance capacitor C7 are 4 nF. I made it. The mutual inductance M of the power transmission coil L3 and the power reception coil L4 and the mutual inductance M2 of the primary relay coil L6 and the secondary relay coil L7 are 0.2 μH.

Here, as a result of performing circuit simulation by changing the input impedance of the load circuit 30 from 1Ω to 64Ω, the amplitude of the resonant current i6 flowing through the load circuit 30 is as shown in Table 2 below.
(Table 2)
Input impedance of load circuit 30, amplitude of resonant current i6 1Ω 1A
2Ω 1A
4Ω 1A
8Ω 0.9A
16Ω 0.8A
32Ω 0.6A
64 Ω 0.35 A

  That is, when the input impedance of the load circuit 30 is 4 Ω or less, the amplitude of the resonance current i6 becomes 1 A according to the equation 8. When the input impedance of the load circuit 30 becomes larger than that, the resonance current i6 becomes smaller.

  The phenomenon that the resonance current i6 becomes smaller than 1A when the input impedance of the load circuit 30 becomes larger than a predetermined value in the first embodiment and the second embodiment is that the frequency of the resonance current i3 is from the optimum resonance frequency of the circuit. I think that it was a phenomenon that affected slightly as follows.

  As the input impedance of the load circuit 30 is increased, the tolerance range of the optimum resonance frequency of the resonance current i3 at which the power reception device relay electromagnetic induction circuit 22 can relay the wireless power to the load circuit 30 narrows, and the optimum resonance frequency It is considered that the value of the resonance current i6 is smaller than the value 1A at the optimum resonance frequency because the frequency shift slightly deviated from the above is not acceptable.

  The present invention is not limited to the embodiments described above, and in the mutual inductance variable means 12a for power transmission device or the mutual inductance variable means 22a for power reception device, the mutual inductance of the primary side relay coil and the secondary side relay coil coil The means for changing may be other means than mechanically moving the primary side relay coil or the secondary side relay coil coil of the relay electromagnetic induction circuit to change the mutual inductance.

  For example, as means for changing the mutual inductance, mutual inductance variable means for switching the mutual inductance by switching the wiring of the relay coil with a switch can be used.

  As another means for changing mutual inductance, mutual inductance variable means for switching mutual inductance can be used by switching and using a plurality of relay electromagnetic induction circuits having different mutual inductances.

  The present invention is used in non-contact power supply to moving objects such as electric vehicles and flying objects, in applications where power is supplied to an electronic device installed on a desk by separating a desk plate, and installed in a living body It can be applied to the application of supplying power by separating the skin of the device. Further, the present invention can be applied to an application of transmitting power without contact between wiring layers of an integrated circuit in a semiconductor integrated circuit.

10 power transmission device, 11 AC power supply circuit, 12 power transmission device relay electromagnetic induction circuit, 12a power transmission device mutual inductance variable means, 13 power transmission resonance circuit, 20 power reception device, 21 power reception resonance circuit, 22 power reception device relay electromagnetic induction circuit, 22a Power receiving device mutual inductance variable means, 30 load circuit, 31 rectification circuit, 32 storage device, 33 load, 40 output power stabilization control means, 41 power source current measurement means, 42 output power control arithmetic means, 50 received power stabilization Control means, 51 load current measuring means, 52 received power control computing means, C1 (for power transmission device) primary side resonance capacity, C2 (for power transmission device) secondary side resonance capacity, C3 power transmission resonance capacity, C4 received power Capacitance for resonance, C5 (for power transmission device) capacitance for resonance, C6 (for power reception device) capacitance for primary side resonance, C7 (for power reception device) capacitance for secondary side resonance, C8 (power reception device) ) Capacitance for resonance, output voltage of E AC power supply circuit, voltage applied to E4 load circuit, voltage of E5 power transmission coil, output current of i1 AC power supply circuit, i2, i3, i4, i5, i6, i7 resonance current, L1 ( For power transmission device) Primary side relay coil, L2 (for power transmission device) secondary side relay coil, L3 power transmission coil, L4 power receiving coil, L6 (for power reception device) Primary side relay coil, L7 (for power reception device) secondary Mutual inductance of the side relay coil, M power transmission coil and receiving coil, mutual inductance of the relay electromagnetic induction circuit for M1 power transmission device, mutual inductance of the relay electromagnetic induction circuit for M2 power reception device

Claims (3)

Wireless power is transmitted by electromagnetic induction from the AC power supply circuit that supplies AC power from the AC power supply circuit of the power transmission device to the power reception coil of the power reception device that is separated by space, AC power is transmitted from the power reception coil to the load circuit, and consumed. Wireless power transmission system,
A relay electromagnetic induction circuit is provided between the AC power supply circuit and the power transmission coil or between the power reception coil and the load circuit, and the relay electromagnetic induction circuit includes a primary side resonance including a primary side relay coil. A wireless power supply comprising: a circuit; a secondary side resonance circuit including a secondary side relay coil; and mutual inductance variable means for making the mutual inductance of the primary side relay coil and the secondary side relay coil variable. Transmission system. The wireless power transmission system according to claim 1,
The power reception device includes a power reception resonance circuit including the power reception coil, and the load circuit.
The power transmission device includes a power transmission resonance circuit including the AC power supply circuit, the relay electromagnetic induction circuit, and the power transmission coil.
The AC power supply circuit is connected to the primary side resonance circuit of the relay electromagnetic induction circuit,
The power transmission resonant circuit is connected to the secondary side resonant circuit,
The alternating current frequency of the alternating current power supply circuit, the resonance frequency of the primary side resonance circuit, and the resonance frequency of the entire secondary side resonance circuit, the power transmission resonance circuit, and the power reception resonance circuit are matched. Wireless power transmission system. The wireless power transmission system according to claim 1,
The power transmission device includes the AC power supply circuit, and a power transmission resonant circuit including the power transmission coil.
The power reception device includes a power reception resonance circuit including the power reception coil, the relay electromagnetic induction circuit, and the load circuit.
The power reception resonance circuit is connected to the primary side resonance circuit of the relay electromagnetic induction circuit,
The load circuit is connected to the secondary side resonance circuit,
The alternating current frequency of the alternating current power supply circuit, the resonance frequency of the entire power transmission resonance circuit, the power reception resonance circuit, and the entire primary side resonance circuit are matched with the resonance frequency of the secondary side resonance circuit. Wireless power transmission system.

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