JP6819951B2 - Wireless power transfer system - Google Patents

Description

The present invention relates to a wireless power transmission system that transmits and consumes electric power from a power supply circuit across 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 in Patent Document 1, the AC magnetic field of the power transmission coil on the power transmission circuit side and the AC magnetic field of the power reception coil of the power reception side resonance circuit on the power reception circuit side are used. A wireless power transmission system has been proposed in which power is transmitted wirelessly from a transmission coil of a power transmission circuit to a power reception coil of a power reception circuit by resonating with each other. In Patent Document 1, the power receiving circuit is composed of a power receiving side resonance circuit including a power receiving coil, a rectifier circuit, and a power storage device, and the AC power received by the power receiving coil of the power receiving side resonance circuit is rectified into DC power by the rectifier circuit. The power storage device is being charged.

Further, in Patent Document 2, in order to improve the impedance mismatch between the power transmitting side and the power receiving side due to the fluctuation of the impedance of the load of the power receiving circuit, a DC voltage conversion circuit is installed between the rectifier circuit and the power storage device to form the circuit. Techniques for matching impedance have been proposed. In Patent Document 2, a chopper circuit is used as the DC voltage conversion circuit, and the impedance conversion ratio is adjusted by changing the width of the switching pulse that opens and closes the switch of the switching element of the chopper circuit.

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

However, in the wireless power transmission system of Patent Document 1, when the transmission coil and the power receiving coil are separated and the mutual inductance of both coils becomes small, the resonance current flowing in the power receiving side resonance circuit becomes small and the power received by the power receiving coil from the power transmitting coil is small. As a result, there is a problem that the power receiving circuit cannot receive a sufficiently large amount of wireless power.

In the wireless power transmission system of Patent Document 2, since a DC voltage conversion circuit is inserted between the rectifier circuit and the load storage device, the impedance conversion ratio of the DC voltage conversion circuit is adjusted to move the load side from the power receiving coil. The impedance of the seen load can be reduced. Therefore, it is considered that the Q value of the resonance of the power receiving side resonance circuit can be increased to increase the resonance current of the power receiving side resonance circuit, thereby increasing the radio power received by the power receiving circuit.

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 load condition.

Therefore, an object of the present invention is to provide a wireless power transmission system that stably supplies electric power to a load when the mutual inductance of a power transmitting coil and a power receiving coil fluctuates.

In order to solve this problem, the present invention transmits wireless power by electromagnetic induction of mutual inductance M from a transmission coil to which AC power is supplied from an AC power supply circuit of a power transmission device to a power receiving coil of a power receiving device separated by a space. A wireless power transmission system for transmitting AC power from the power receiving coil to a load circuit for consumption, wherein the power receiving device has a power receiving resonance circuit including the power receiving coil and the load circuit.
A relay electromagnetic induction circuit is provided between the AC power supply circuit of the power transmission device and the power transmission coil.
The relay electromagnetic induction circuit has a primary side resonance circuit composed of a primary side relay coil and a primary side resonance capacitance, and the primary side relay coil and the transmission coil are electromagnetically induced by a mutual inductance M1. It has a mutual inductance variable means for making the mutual inductance M1 variable.
It has a power transmission resonance circuit composed of the power transmission coil and a power transmission resonance capacity.
It has a load current measuring means for measuring the current of the load circuit and a received power control calculation means.
The AC power supply circuit is connected to the primary side resonance circuit of the relay electromagnetic induction circuit, and the AC frequency of the AC power supply circuit, the resonance frequency of the primary side resonance circuit, the transmission resonance circuit, and the power reception resonance Match the resonant frequencies of the entire circuit of the circuit,
The power supply current measuring means measures the fluctuation of the output current of the AC power supply circuit,
The output power control calculation means operates the mutual inductance variable means so as to make the output current of the AC power supply circuit a constant value.
It is a wireless power transmission system characterized by stabilizing the supply of electric power to the load circuit .
Further, the present invention is the above-mentioned wireless power transmission system.
So that the output power control calculation means keeps the output current constant.
By operating the mutual inductance variable means and changing the mutual inductance M1 in proportion to the mutual inductance M,
Stabilize the power supply to the load circuit
It is a wireless power transmission system characterized by this.

In the present invention, according to this configuration, the mutual inductance variable means follows and changes the mutual inductance of the primary side relay coil of the relay electromagnetic induction circuit and the power transmission coil with respect to the fluctuation of the mutual inductance of the power transmission coil and the power reception coil. This has the effect of being able to stably supply power to the load.

Further, in the present invention, wireless power is transmitted from a power transmitting coil to which AC power is supplied from an AC power supply circuit of a power transmitting device to a power receiving coil of a power receiving device separated by a space by electromagnetic induction of mutual inductance M, and from the power receiving coil. A wireless power transmission system that transmits AC power to a load circuit and consumes it.
The power transmission device has the AC power supply circuit and a power transmission resonance circuit including the power transmission coil, and a relay electromagnetic induction circuit is provided between the power reception coil of the power reception device and the load circuit.
The relay electromagnetic induction circuit has a power receiving resonance circuit composed of the power receiving coil and a power receiving resonance capacitance, and has a secondary side relay coil for electromagnetic induction with the power receiving coil and mutual inductance M2, and the secondary side relay. It has a secondary resonance circuit composed of a coil and a capacitance for secondary resonance, and has a mutual inductance variable means for making the mutual inductance M2 variable.
It has a load current measuring means for measuring the current of the secondary relay coil and a power receiving power control calculation means.
The load circuit is connected to the secondary resonance circuit, and the AC frequency of the AC power supply circuit is matched with the resonance frequency of the entire circuit of the transmission resonance circuit, the power reception resonance circuit, and the secondary resonance circuit. ,
The load current measuring means measures the fluctuation of the current of the secondary relay coil, and the load current measuring means measures the fluctuation of the current.
The received power control calculation means operates the mutual inductance variable means so as to make the current of the secondary side relay coil a constant value.
It is a wireless power transmission system characterized by stabilizing the supply of electric power to the load circuit .
Further, the present invention is the above-mentioned wireless power transmission system.
The received power control calculation means keeps the current of the secondary relay coil constant.
By operating the mutual inductance variable means and changing the mutual inductance M2 in proportion to the mutual inductance M,
Stabilize the power supply to the load circuit
It is a wireless power transmission system characterized by this.

In the present invention, according to this configuration, the mutual inductance variable means follows the mutual inductance of the primary side relay coil and the secondary side relay coil of the relay electromagnetic induction circuit with respect to the fluctuation of the mutual inductance of the power transmission coil and the power reception coil. This has the effect of being able to stably supply power to the load.

It is a circuit diagram which shows the whole of the power transmission device and the power receiving device of the wireless power transmission system of the 1st Embodiment of this invention. It is a schematic plan view which shows the structure of the mutual inductance variable means on the power transmission apparatus side of 1st Embodiment of this invention. It is a circuit diagram which shows the whole of the power transmission device and the power receiving device of the wireless power transmission system of the 2nd Embodiment of this invention. It is a schematic plan view which shows the structure of the mutual inductance variable means on the power transmission apparatus side of the 2nd Embodiment of this invention. It is a circuit diagram which shows the whole of the power transmission device and the power receiving device of the wireless power transmission system of the 4th Embodiment of this invention. It is a schematic plan view which shows the structure of the mutual inductance variable means on the power transmission apparatus side of the 4th Embodiment of this invention. It is a circuit diagram which shows the whole of the power transmission device and the power receiving device of the wireless power transmission system of the 5th Embodiment of this invention. It is a circuit diagram which shows the whole of the power transmission device and the power receiving device of the wireless power transmission system of the sixth embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
The first embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown 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 brought close to each other and electromagnetically induced by the mutual inductance M, and a space is separated from the power transmission coil L3 to the power reception coil L4. Transmit wireless power. A load circuit 30 is connected to the power receiving resonance circuit 21 of the power receiving device 20, and the load circuit 30 consumes power.

(Power transmission device 10)
The power transmission device 10 is composed of an AC power supply circuit 11 that outputs a constant voltage AC of the output voltage E of the frequency f, a relay electromagnetic induction circuit 12 for the power transmission device 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 the output current i1 of the frequency f at a constant voltage. The primary side resonance circuit of the relay electromagnetic induction circuit 12 for a power transmission device is connected in series to the AC power supply circuit 11 to pass an output current i1.

(Relay electromagnetic induction circuit 12 for power transmission device)
The relay electromagnetic induction circuit 12 for the power transmission device 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 the mutual inductance variable means 12a for the power transmission device which makes the mutual inductance M1 of the secondary side relay coil L2 variable.

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

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

Here, the secondary side relay coil L2 and the secondary side resonance capacitance C2 of the transmission device relay electromagnetic induction circuit 12 are connected in series to the transmission resonance capacitance C3 of the transmission resonance circuit 13 and the transmission coil L3, respectively. 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 device)
The mutual inductance variable means 12a for the power transmission device is used to make the mutual inductance M1 of the electromagnetic induction of the primary side relay coil L1 and the secondary side relay coil L2 variable. The mutual inductance variable means 12a for the power transmission device 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, and 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 coil L2.

For example, the mutual inductance variable means 12a for a power transmission device that freely changes the interval at which the primary side relay coil L1 and the secondary side relay coil L2 face each other is used, or the primary side relay coil is as shown in the plan view of FIG. By using the mutual inductance variable means 12a for the power transmission device that freely shifts the axes of the L1 and the secondary relay coil L2, the mutual inductance M1 between the two coils can be freely adjusted.

(Power transmission resonance circuit 13)
The power transmission resonance circuit 13 of the power transmission device 10 is connected in series to the secondary resonance circuit of the relay electromagnetic induction circuit 12 for the power transmission device. The power transmission resonance circuit 13 is composed of a power transmission resonance capacitance C3 and a power transmission coil L3. The entire circuit including the transmission resonance circuit 13 and the secondary side resonance circuit connected in series with the transmission resonance circuit 13 is resonated at the same resonance frequency f as the resonance frequency f of the primary side resonance circuit, and the resonance current i2 is passed.

(Power receiving device 20)
The power receiving device 20 is configured by connecting the load circuit 30 in series with the power receiving resonance circuit 21. The power receiving resonance circuit 21 is configured by connecting a power receiving coil L4 that electromagnetically induces the power transmission coil L3 of the power transmission resonance circuit 13 and a power receiving resonance capacitance C4 in series. The power receiving resonance circuit 21 is resonated at the same resonance frequency f as the transmission resonance circuit 13, and the resonance current i3 is passed through the load circuit 30.

(Load circuit 30)
The load circuit 30 includes a rectifier circuit 31 connected to the power receiving resonance circuit 21, a power storage device 32, and a load 33. The rectifier circuit 31 rectifies the resonance current i3 of the power receiving resonance circuit 21 to direct current. The DC power output by the rectifier circuit 31 is stored in the power storage device 32 composed of a capacitor and a secondary battery, and is consumed by a 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 device)
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, the secondary side relay coil L2 is electromagnetically coupled to the primary side relay coil L1 by the mutual inductance M1. The resonance current i2 flowing through the side relay coil L2 and the transmission coil L3 of the transmission resonance circuit 13 can be calculated by the following equation 1.
(Equation 1) i2 = E / (jωM1)

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

According to this equation 1, the primary side relay coil L1 and the secondary side relay coil L2 are fixed 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 constant voltage AC power supply circuit 11. When the mutual inductance M1 of the above is made constant, the resonance current i2 flowing through the secondary side resonance circuit and the 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 a power transmission device connected to the constant voltage AC power supply circuit 11 sets a constant value of the resonance current i2 flowing through the power transmission coil L3 without being affected by the mutual inductance M of the power transmission coil L3 and the power reception coil L4. Can be limited to.

By changing the number of turns of the coil of the primary side relay coil L1 and the number of turns of the coil of the secondary side relay coil L2 of the relay electromagnetic induction circuit 12 for the power transmission device, the secondary side relay coil L2 and the power transmission resonance circuit 13 The resonance current i2 flowing through the transmission coil L3 of the above can be changed. For example, if the number of turns of the coil of the secondary side relay coil L2 is halved with respect to the number of turns of the coil of the primary side relay coil L1 of the relay electromagnetic induction circuit 12 for a power transmission device, 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 receiving device 20 affects the output current i1 of the AC power supply circuit 11 in relation to the following equation 2.
(Equation 2) i1 = (M / M1) i3

Equation 2 means that when the resonance current i3 flows through the load circuit 30, the output current i1 represented by Equation 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 the square of (M1 / M) of the input impedance of the load circuit 30. Therefore, when the mutual inductance M of the power transmitting coil L3 and the power receiving coil L4 becomes small, the image impedance thereof becomes large, which means that the output current i1 of the AC power supply circuit 11 becomes small.

Conventionally, in a circuit in which a transmission resonance circuit 13 is connected in series with a constant voltage AC power supply circuit 11, the output current i1 of the AC power supply circuit 11 flows through the transmission coil L3 of the transmission resonance circuit 13, and the resonance current i2 of the transmission coil L3 flows. = Output current i1, but when the distance between the transmission coil L3 and the power receiving coil L4 becomes large and the mutual inductance M becomes small, there is a problem that the resonance current i2 and the output current i1 become infinitely large.

In the present invention, this problem is solved by installing the relay electromagnetic induction circuit 12 for a power transmission device between the constant voltage AC power supply circuit 11 and the power transmission resonance circuit 13, and the resonance flowing through the power transmission coil L3 of the power transmission resonance circuit 13 is solved. There is an effect that the current i2 can be limited to a constant value.

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

When the AC frequency of the AC power supply circuit 11 deviates from the resonance frequency f of the transmission resonance circuit 13 and the relay electromagnetic induction circuit 12 for the transmission device, an infinitely large resonance current i2 flows through the transmission coil L3 of the transmission resonance circuit 13. Is possible.

Therefore, it is desirable to provide a frequency stabilization circuit that always matches the frequency of the AC power supply circuit 11 with the resonance frequency f of the transmission resonance circuit 13 and the relay electromagnetic induction circuit 12 for the transmission device. Further, when the frequency of the AC power supply circuit 11 deviates from the resonance frequency f of the transmission resonance circuit 13 and the relay electromagnetic induction circuit 12 for the transmission device, the connection in the middle of the circuit from the AC power supply circuit 11 to the transmission coil L3 is disconnected, which is safe. It is desirable to provide a circuit.

(Voltage E4 applied to the load circuit 30)
Since the resonance current i2 flowing through the transmission coil L3 is represented by the equation 1, the induced electromotive force E4 represented by the following equation 3 is generated in the power receiving coil L4 that electromagnetically induces the transmission coil L3 with the mutual inductance M. The induced electromotive force E4 is applied to the load circuit 30.
(Equation 3) E4 = jωM × i2 = (M / M1) E
This equation 3 shows 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 means 40 is composed of a power supply current measuring means 41 for measuring the output current i1 of the constant voltage AC power supply circuit 11 and an output power control calculation means 42. The output power control calculation means 42 of the output power stabilization control means 40 operates the mutual inductance variable means 12a for the power transmission device so that the output current i1 of the AC power supply circuit 11 measured by the power supply current measuring means 41 becomes a constant value. By controlling, the supply of electric 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 fluctuates, the mutual inductance M of the electromagnetic induction of the power transmission coil L3 and the power reception coil L4 fluctuates. In that case, the power supply current measuring means 41 of the output power stabilization control means 40 measures the fluctuation of the output current i1 of the AC power supply circuit 11, and based on the measurement result, the mutual inductance variable means 12a for the power transmission device is operated. The mutual inductance M1 of the primary side relay coil L1 and the secondary side relay coil L2 is changed in proportion to the mutual inductance M.

By the control, the induced electromotive force E4 induced in the power receiving coil L4 of the power receiving resonance circuit 21 is maintained at a constant value according to the equation 3, and the induced electromotive force E4 is applied to the load circuit 30 to stabilize the load circuit 30. It has the effect of being able to supply a constant amount of power and stabilizing the resonant current i3 flowing through the load circuit 30. At that time, the output current i1 of the AC power supply circuit 11 can also be stabilized constantly according to 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 by using the power supply current measuring means 41. That is, the power supply current measuring means 41 measures the increase in the output current i1 of the AC power supply circuit 11 to detect the approach of the power receiving coil L4 to the power transmission coil L3. Here, in order to increase the detection sensitivity of the power receiving coil L4, the output power control calculation means 42 intermittently reduces the mutual inductance M1 to reduce the mutual inductance M1 to pass the current i2 to 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, like the first embodiment, comprises the power transmission device 10 and the power receiving device 20. The difference between the second embodiment and the first embodiment is that the transmission resonance circuit 13 also serves as the secondary resonance circuit of the relay electromagnetic induction circuit 12 for the transmission device, as shown in the circuit diagram of FIG. Is.

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

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

(Mutual inductance variable means 12a for power transmission device)
As shown in the plan view of FIG. 4, the mutual inductance variable means 12a for the power transmission device can freely change the overlapping area of the primary side relay coil L1 of the relay electromagnetic induction circuit 12 for the power transmission device and the power transmission coil L3 of the power transmission resonance circuit 13. By using the mutual inductance variable means 12a for the power transmission device, the mutual inductance M1 between both coils can be freely adjusted. Further, the mutual inductance variable means 12a for the power transmission device is configured to freely change the interval at which the primary side relay coil L1 of the relay electromagnetic induction circuit 12 for the power transmission device and the power transmission coil L3 of the power transmission resonance circuit 13 face each other. Inductance variable means 12a can also be used.

<Third embodiment>
Similar to the first embodiment, the third embodiment includes a power transmission device 10 and a power receiving device 20, and the power transmission device 10 has a relay electromagnetic induction circuit 12 for the power transmission device. 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 a mutual inductance M to form an integrated circuit and resonate, and the resonance frequency of the integrated circuit. Has a resonance frequency different from the resonance frequency of the power transmission resonance circuit 13 alone and the resonance frequency of the power reception resonance circuit 21 alone.

The difference between the third embodiment and the first and second embodiments is that the resonance frequency of the integrated circuit in which the transmission coil L3 of the transmission resonance circuit 13 and the power reception coil L4 of the power reception resonance circuit 21 are electromagnetically coupled and the transmission The point is that the resonance frequency of the relay electromagnetic induction circuit 12 for the device and the frequency f of the AC power supply circuit 11 are set to the same frequency to transmit power. Further, it is different from the first and second embodiments that the independent resonance frequency of the power transmission resonance circuit 13 and the independent resonance frequency of the power reception resonance circuit 21 are different from the frequency f of the AC power supply circuit 11.

(Secondary resonance current limiting function)
Also in the third embodiment, the primary side relay coil L1 and the secondary side are fixed 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 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 transmission coil L3 of the secondary side resonance circuit and the transmission resonance circuit 13 is maintained at a constant value represented by Equation 1, and the secondary side resonance current limit is maintained. 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 with the resonance current i2 flowing through the transmission coil L3 of the integrated circuit.

The ratio of the resonance current i3 flowing through the power receiving coil L4 to the resonance current i2 flowing through the power transmission coil L3 is a constant value related to the self-inductance of the power transmission coil L3 and the power reception coil L4. Therefore, in the third embodiment, in order to make the value of the resonance current i3 constant, the mutual inductance variable means 12a for the power transmission device is fixed, and the primary side relay coils L1 and 2 of the relay electromagnetic induction circuit 12 for the power transmission device 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-described embodiment in that the power transmission resonance circuit 13 and the secondary resonance circuit of the relay electromagnetic induction circuit 12 for the power transmission device are connected in parallel via the resonance capacitance. .. That is, a circuit in which the resonance capacitance C5 and the transmission coil L3 are connected in parallel with the secondary side relay coil L2 of the relay electromagnetic induction circuit 12 for the power transmission device is configured, and the circuit is resonated at the frequency f of the AC power supply circuit 11.

The fourth embodiment, like the first embodiment, comprises the power transmission device 10 and the power receiving device 20. The power transmission device 10 is composed of an AC power supply circuit 11 having a frequency f, a relay electromagnetic induction circuit 12 for a power transmission device that resonates at the frequency f, and a power transmission resonance circuit 13. The power receiving coil L4 of the power receiving device 20 is electromagnetically induced by the power transmitting coil L3 of the power transmitting resonance circuit 13 with a mutual inductance M, and the AC power supplied by the AC power supply circuit 11 is transferred from the power transmitting coil L3 to the power receiving coil L4 separated by a space. Power is transmitted wirelessly. A load circuit 30 is connected to the power receiving resonance circuit 21 of the power receiving device 20, and the load circuit 30 consumes power.

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

By connecting the secondary side relay coil L2 of the relay electromagnetic induction circuit 12 for a power transmission device to the resonance capacitance C5 and connecting the power transmission coil L3 of the power transmission resonance circuit 13 in parallel with the resonance capacitance C5, the resonance capacitance C5 Is shared by the secondary resonance circuit and the transmission resonance circuit 13 of the relay electromagnetic induction circuit 12 for the power transmission device. The primary side relay coil L1 and the secondary side relay coil L2 of the primary side resonance circuit of the relay electromagnetic induction circuit 12 for a power transmission device are electromagnetically induced by the mutual inductance M1. The primary side resonance circuit, the secondary side resonance circuit, and the 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 device)
By making the relative positions of the primary side relay coil L1 and the secondary side relay coil L2 variable by using the mutual inductance variable means 12a for the power transmission device as shown in the plan view of FIG. 6, the primary side relay coil L1 And the mutual inductance M1 of the electromagnetic induction of the secondary side relay coil L2 is made variable.

(Current limiting function)
The AC power supply circuit 11 is connected in series with the primary resonance circuit to pass the output current i1 of the AC power supply circuit 11. The secondary side 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 capacitance C5. A resonance current i2 is passed through the secondary relay coil L2. A resonance current i4 is passed through the power transmission coil L3 of the power transmission resonance 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 side relay coil L2 and the power transmission coil L3 are connected in parallel with the resonance capacitance C5, and the primary side relay coil L1 and the secondary side relay coil L2 are electromagnetically coupled by the mutual inductance M1, the circuit simulation is performed. As a result of analyzing the voltage E5 of the power transmission coil L3, the following equation 4 which holds approximately is obtained.
(Equation 4) E5 = E / k1
That is, the voltage E5 of the power transmission coil L3 is the 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.
(Equation 5) i4 = E5 / (jωL3) = E / (jωL3 × k1)

Similar to the first embodiment, the fourth embodiment is also on the primary side 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 constant voltage AC power supply circuit 11. 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 transmission coil L3 to the value of Equation 5 or less. That is, the relay electromagnetic induction circuit 12 for a power transmission device connected to the constant voltage AC power supply circuit 11 sets a constant value of the resonance current i4 flowing through the power transmission coil L3 without being affected by the mutual inductance M of the power transmission coil L3 and the power reception coil L4. It can be limited to:

(Power receiving device 20 etc.)
The power receiving device 20 of the fourth embodiment and the output power stabilizing 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 transmission coil L3 is represented by the equation 5, the induced electromotive force E4 generated in the power receiving coil L4 having the mutual inductance M with the transmission coil L3 is represented by the following approximate equation 6. The induced electromotive force E4 is applied to the load circuit 30.
(Equation 6) E4 = jωM × i4 = (k / k1) E

In this equation 6, the induced electromotive force E4 applied to the load circuit 30 sets the coupling coefficient k = (M / L3) between the power transmitting coil L3 and the power receiving coil L4 to the primary side relay coil L1 of the power transmitting 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 relay coil L2.

On the other hand, the output current i1 of the AC power supply circuit 11 is represented 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

Equation 7 means that when the resonance current i3 flows through the load circuit 30, the output current i1 represented by the equation 7 flows out from the AC power supply circuit 11. This means that the image impedance at the position of the output terminal of the AC power supply circuit 11 is the square 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 transmitting coil L3 and the power receiving coil L4 becomes small, the image impedance at the position of the output terminal of the AC power supply circuit 11 becomes large, and the output current i1 of the AC power supply circuit 11 becomes small. Means to be.

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 the power reception coil L4 fluctuates, the power supply current measurement of the output power stabilization control means 40 The means 41 detects the fluctuation by detecting the output current i1 of the AC power supply circuit 11.

Then, the output power control calculation means 42 controls the mutual inductance variable means 12a for the power transmission device of the relay electromagnetic induction circuit 12 for the power transmission device, and mutually inverts the mutual inductance M1 of the primary side relay coil L1 and the secondary side relay coil L2. Change in proportion to the inductance M. By this control, the induced electromotive force E4 induced in the power receiving coil L4 of the power receiving resonance circuit 21 can be maintained at a constant value and applied to the load circuit 30, which has the effect of stably supplying power to the load circuit 30.

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

In the fifth embodiment as well, similarly to 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 the mutual inductance M to electromagnetically induce the power transmission coil L3. 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, a conventional power transmission device 10 having no relay electromagnetic induction circuit 12 for the power transmission device can be used. Alternatively, the power transmission device 10 may use a power transmission device having a circuit according to any one of the first to fourth embodiments of the present invention. A resonance current i5 is passed through the power transmission coil L3 of the power transmission device 10.

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

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

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

In the present embodiment, the primary resonance circuit is connected in series with the power receiving resonance circuit 21, the resonance current i3 of the power receiving resonance circuit 21 is passed through the primary resonance circuit, and the load connected in series with the secondary resonance circuit. A resonant current i6 is passed through the circuit 30.

The power receiving resonance circuit 21 connected in series and the entire primary resonance circuit are resonated at the resonance frequency f. The resonance frequency f and the resonance frequency f of the secondary resonance circuit are matched. Further, an alternating current having a frequency f is passed through the power transmission coil L3 of the power transmission device 10.

(Mutual inductance variable means 22a for power receiving device)
Using the mutual inductance variable means 22a for the 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 so that it can be freely adjusted. The mutual inductance variable means 22a for the power receiving device has the same configuration as the mutual inductance variable means 12a for the power transmitting device of the first embodiment, and is the primary side relay coil L6 or the secondary side of the relay electromagnetic induction circuit 22 for the power receiving device. A means can be used in which the relay coil coil L7 is mechanically moved to change the relative positions of the primary side relay coil L6 and the secondary side relay coil coil L7 to change the mutual inductance M2.

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

(Secondary resonance current adjustment function)
When the mutual inductance variable means 22a for the power receiving device is used to adjust the mutual inductance M2 of the electromagnetic induction of the primary side relay coil L6 and the secondary side relay coil L7 by circuit simulation, the secondary side relay coil L7 and its series As a result of analyzing the resonance current i6 flowing through the load circuit 30 connected to the above, the following approximate equation 8 was found.
(Equation 8) i6 = (M / M2) i5

This equation 8 means that when the resonance current i5 of the transmission coil L3 is constant, the resonance current i6 flowing in the load circuit 30 flows the current of the value of the equation 8 without being affected by the input impedance of the load circuit 30. To 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 becomes large. The large resonance current i3 flows through the primary side relay coil L6 and is electromagnetically induced to induce a large induced electromotive force E4 in the secondary side relay coil L7, and the induced electromotive force E4 is applied to the load circuit 30.

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

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

(Power 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 through the load circuit 30 or the current flowing through the load 33, and a received power control calculation means 52. The power receiving power control calculation means 52 of the power receiving power stabilization control means 50 controls the mutual inductance variable means 22a for the power receiving device in order to make the current value measured by the load current measuring means 51 constant, and power is transmitted from the power transmission coil L3. Stable power reception.

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, the mutual inductance M of the electromagnetic induction of the power transmission coil L3 and the power reception coil L4 fluctuates. In that case, the load current measuring means 51 of the power receiving power stabilization control means 50 measures the fluctuation of the resonance current i6 flowing in the load circuit 30, and based on the measurement result, the mutual inductance variable means 22a for the power receiving device is operated. The mutual inductance M2 of the primary side relay coil L6 and the secondary side relay coil L7 is changed in proportion to the mutual inductance M. By the control, there is an effect that the resonance current i6 flowing into the load circuit 30 can be stably stabilized.

Further, the power receiving power control calculation means 52 searches for the power transmission coil L3 of the power transmission device 10 by using the load current measuring means 51 when the power receiving device 20 approaches the power transmission device 10 from a position away from the power transmission device 10. .. That is, the load current measuring means 51 measures the increase in the resonance current i6 flowing through the load circuit 30 to detect the approach of the power receiving coil L4 to the power transmission coil L3. Here, in order to increase the detection sensitivity of the power transmission coil L3, the received power control calculation means 52 intermittently controls to reduce the mutual inductance M2 and increase the resonance current i6 flowing in the load circuit 30.

When the power transmission device 10 is provided with the output power stabilization control means 40 as in the first embodiment, the output power stabilization control means 40 of the power transmission device 10 and the power reception power stabilization of the power receiving device 20 are stabilized. The control means 50 will compete. In that case, the output power stabilization control means 40 of the power transmission device 10 and the power reception power stabilization control means 50 of the power reception device 20 wirelessly communicate with each other to stabilize the transmission of wireless power by using either power stabilization control means. It is desirable to decide and control whether to make it.

(Modification example 1)
The power receiving resonance circuit 21 of the fifth embodiment is a circuit in which the power receiving resonance circuit 21 also serves as the primary side resonance circuit of the relay electromagnetic induction circuit 22 for the power receiving device, similarly to the transmission resonance circuit 13 of the second embodiment. Can be configured. That is, the power 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 transmitting device relay electromagnetic induction circuit. Twelve primary resonance capacitances C6 can be included. By resonating the power receiving coil L4 of the power receiving resonance circuit 21 and the power receiving resonance capacitance C4 at the frequency f of the AC power supply circuit 11, the power receiving from the AC power supply circuit 11 is separated from the power transmission coil L3 in the same manner as described 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, similarly to the fifth embodiment, the resonance current i5 is passed through the transmission coil L3, and the relay electromagnetic induction circuit 22 for the power receiving device is inserted between the power receiving resonance circuit 21 and the load circuit 30 of the power receiving device 20. Install. The sixth embodiment differs from the fifth embodiment in that the power receiving resonance circuit 21 and the primary side resonance circuit of the power receiving device relay electromagnetic induction circuit 22 are connected in parallel via a resonance capacitance. is there. That is, the resonance capacitance C8 and the primary side relay coil L6 of the power receiving device relay electromagnetic induction circuit 22 are connected in parallel with the power receiving coil L4 to make the power receiving resonance circuit 21 and the primary side resonance circuit the resonance capacitance. It is connected in parallel via C8, and 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 device relay electromagnetic induction circuit 22 in parallel with the resonance capacitance C8, the resonance capacitance C8 is shared by the power receiving resonance circuit 21 and the primary side resonance circuit of the power receiving device relay electromagnetic induction circuit 22.

A resonance current i3 is passed through the power receiving coil L4 connected in parallel with the resonance capacitance C8, and a resonance current i7 is passed through the primary relay coil L6. In the relay electromagnetic induction circuit 22 for a power receiving device, the primary side relay coil L6 and the secondary side relay coil L7 are electromagnetically induced by the mutual inductance M2. A load circuit 30 is connected in series with the secondary side relay coil L7 of the secondary side resonance circuit, and a resonance current i6 is passed therethrough. Then, the power receiving 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.

When the mutual inductance variable means 22a for the power receiving device is used to adjust the mutual inductance M2 of the electromagnetic induction of the primary side relay coil L6 and the secondary side relay coil L7 by circuit simulation, the secondary side relay coil L7 and its series As a result of analyzing the resonance current i6 flowing through the load circuit 30 connected to the above, there was a relationship 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 transmission coil L3 is constant, the resonance current i6 flowing in the load circuit 30 flows the current of the value of the equation 9 without being affected by the input impedance of the load circuit 30. To do. The resonance 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 the 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 the power receiving device are fixed to constant values, the power transmitting coil L3 and the power receiving coil L4 When the mutual inductance M becomes small, the resonance current i6 flowing through the secondary relay coil L7 becomes small. The mutual inductance variable means 22a for the power receiving device is used to change the mutual inductance M2 of the relay electromagnetic induction circuit 22 for the power receiving device so as to follow the mutual inductance M of the power transmitting coil L3 and the power receiving coil L4, thereby relaying to the secondary side. The resonance 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 set to 1.1 μH, and the power transmission coil L3 has a resonance current i5 having a frequency f of 1.7 MHz and an amplitude of 1 A. Shed. The power receiving coil L4, the primary side relay coil L6, and the secondary side relay coil L7 of the power receiving device 20 are set to 1.1 μH, and the power receiving resonance capacitance C4, the primary resonance capacitance C6, and the secondary resonance capacitance C7 are 8 nF. I made it. The mutual inductance M of the power transmitting coil L3 and the power receiving coil L4 and the mutual inductance M2 of the primary side relay coil L6 and the secondary side relay coil L7 were set to 0.1 μH.

Here, as a result of performing a 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 resonance current i6 1Ω 1A
2Ω 1A
4Ω 0.9A
8Ω 0.8A
16Ω 0.6A
32Ω 0.35A

That is, when the input impedance of the load circuit 30 is 2Ω or less, the amplitude of the resonance current i6 becomes 1A according to the equation 8. When the input impedance of the load circuit 30 became larger than that, the resonance current i6 became 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 set to 2.2 μH, and the power transmission coil L3 has a resonance current i5 having a frequency f of 1.7 MHz and an amplitude of 1 A. Shed. The power receiving coil L4, the primary side relay coil L6, and the secondary side relay coil L7 of the power receiving device 20 are set to 2.2 μH, and the power receiving resonance capacitance C4, the primary resonance capacitance C6, and the secondary resonance capacitance C7 are set to 4 nF. I made it. The mutual inductance M of the power transmitting coil L3 and the power receiving coil L4 and the mutual inductance M2 of the primary side relay coil L6 and the secondary side relay coil L7 are set to 0.2 μH.

Here, as a result of performing a circuit simulation by changing the input impedance of the load circuit 30 from 1Ω to 64Ω, the amplitude of the resonance 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 resonance current i6 1Ω 1A
2Ω 1A
4Ω 1A
8Ω 0.9A
16Ω 0.8A
32Ω 0.6A
64Ω 0.35A

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

In the first and second embodiments, 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 is that the frequency of the resonance current i3 is from the optimum resonance frequency of the circuit. I think that the slight deviation affected the phenomenon as follows.

As the input impedance of the load circuit 30 is increased, the allowable range of the optimum resonance frequency of the resonance current i3 at which the relay electromagnetic induction circuit 22 for the power receiving device can relay the wireless power to the load circuit 30 becomes narrower, and the optimum resonance frequency becomes narrower. It is considered that the value of the resonance current i6 is smaller than the value of 1A at the optimum resonance frequency because the deviation of the frequency slightly deviated from the above is no longer allowed.

The present invention is not limited to the above embodiment, and the mutual inductance of the primary side relay coil and the secondary side relay coil coil is determined in the mutual inductance variable means 12a for the power transmission device or the mutual inductance variable means 22a for the power receiving device. As the means for changing, means other than the means for 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 can also be used.

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

As another means for changing the mutual inductance, it is also possible to use a mutual inductance variable means for switching the mutual inductance by switching a plurality of relay electromagnetic induction circuits having different mutual inductances with a switch.

The present invention is used to supply electric power to a moving body such as an electric vehicle or a flying object in a non-contact manner, to supply electric power to an electronic device installed on a desk across a desk plate, or to be installed in a living body. It can be applied to the application of supplying electric power to the device by separating the skin. Further, it can be applied to applications in which electric power is transmitted non-contact between wiring layers of an integrated circuit in a semiconductor integrated circuit.

10 power transmission device, 11 AC power supply circuit, 12 relay electromagnetic induction circuit for power transmission device, 12a mutual inductance variable means for power transmission device, 13 transmission resonance circuit, 20 power receiving device, 21 power receiving resonance circuit, 22 relay electromagnetic induction circuit for power receiving device, 22a Mutual inductance variable means for power receiving device, 30 load circuit, 31 rectifying circuit, 32 power storage device, 33 load, 40 output power stabilizing control means, 41 power supply current measuring means, 42 output power control calculation means, 50 power receiving power stabilization Control means, 51 load current measuring means, 52 received power control calculation 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 power reception Resonance capacity, C5 (for power transmission device) resonance capacity, C6 (for power receiving device) primary side resonance capacity, C7 (for power receiving device) secondary side resonance capacity, C8 (for power receiving device) resonance capacity, Output voltage of E AC power supply circuit, voltage applied to E4 load circuit, voltage of E5 transmission coil, output current of i1 AC power supply circuit, i2, i3, i4, i5, i6, i7 resonance current, L1 (for power transmission device) 1 Next side relay coil, L2 (for power supply device) secondary side relay coil, L3 transmission coil, L4 power receiving coil, L6 (for power receiving device) primary side relay coil, L7 (for power receiving device) secondary side relay coil, M Mutual inductance of transmission coil and power receiving coil, mutual inductance of relay electromagnetic induction circuit for M1 power transmission device, mutual inductance of relay electromagnetic induction circuit for M2 power receiving device

Claims (4)

Wireless power is transmitted by electromagnetic induction of mutual inductance M from the transmission coil that supplies AC power from the AC power supply circuit of the power transmission device to the power receiving coil of the power receiving device that is separated by space, and the AC power is transmitted from the power receiving coil to the load circuit. A wireless power transmission system that transmits and consumes
The power receiving device has a power receiving resonance circuit including the power receiving coil and the load circuit.
A relay electromagnetic induction circuit is provided between the AC power supply circuit of the power transmission device and the power transmission coil.
The relay electromagnetic induction circuit has a primary side resonance circuit composed of a primary side relay coil and a primary side resonance capacitance.
It has a mutual inductance variable means for electromagnetically inducing the primary side relay coil and the power transmission coil with a mutual inductance M1 to make the mutual inductance M1 variable.
It has a power transmission resonance circuit composed of the power transmission coil and a power transmission resonance capacity.
It has a power supply current measuring means for measuring the output current of the AC power supply circuit and an output power control calculation means.
The AC power supply circuit is connected to the primary resonance circuit of the relay electromagnetic induction circuit.
The AC frequency of the AC power supply circuit, the resonance frequency of the primary resonance circuit, and the resonance frequency of the entire circuit of the transmission resonance circuit and the power reception resonance circuit are matched.
The power supply current measuring means measures the fluctuation of the output current of the AC power supply circuit,
The output power control calculation means operates the mutual inductance variable means so as to make the output current a constant value.
A wireless power transmission system characterized by stabilizing the supply of electric power to the load circuit . The wireless power transmission system according to claim 1.
So that the output power control calculation means keeps the output current constant.
By operating the mutual inductance variable means and changing the mutual inductance M1 in proportion to the mutual inductance M,
Stabilize the power supply to the load circuit
A wireless power transmission system characterized by that. Wireless power is transmitted by electromagnetic induction of mutual inductance M from the transmission coil that supplies AC power from the AC power supply circuit of the power transmission device to the power receiving coil of the power receiving device that is separated by space, and the AC power is transmitted from the power receiving coil to the load circuit. A wireless power transmission system that transmits and consumes
The power transmission device includes the AC power supply circuit and a power transmission resonance circuit including the power transmission coil.
A relay electromagnetic induction circuit is provided between the power receiving coil of the power receiving device and the load circuit.
The relay electromagnetic induction circuit has a power receiving resonance circuit composed of the power receiving coil and a power receiving resonance capacitance.
It has a secondary side relay coil that is electromagnetically induced by the mutual inductance M2 with the power receiving coil.
It has a secondary resonance circuit composed of the secondary relay coil and the secondary resonance capacitance.
It has a mutual inductance variable means for making the mutual inductance M2 variable.
It has a load current measuring means for measuring the current of the secondary relay coil and a power receiving power control calculation means.
The load circuit is connected to the secondary resonance circuit,
Match the AC frequency of the AC power supply circuit with the resonance frequency of the entire circuit of the transmission resonance circuit, the power reception resonance circuit, and the secondary side resonance circuit.
The load current measuring means measures the fluctuation of the current of the secondary relay coil, and the load current measuring means measures the fluctuation of the current.
The received power control calculation means operates the mutual inductance variable means so as to make the current of the secondary side relay coil a constant value.
A wireless power transmission system characterized by stabilizing the supply of electric power to the load circuit . The wireless power transmission system according to claim 3.
The received power control calculation means keeps the current of the secondary relay coil constant.
By operating the mutual inductance variable means and changing the mutual inductance M2 in proportion to the mutual inductance M,
Stabilize the power supply to the load circuit
A wireless power transmission system characterized by that.

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