WO2016114158A1 - Wireless power transmission system - Google Patents

Abstract

In the present invention, a relay cable resonator is configured by connecting, in parallel, a shared capacitor and a plurality of loop-shaped relay coils to a pair of feeding lines, which are formed by facing, in parallel, surfaces of two lines at a distance apart of one-third or less of the width of the line surfaces. A loop-shaped transmission coil in which a transmission system capacitor and a power supply circuit are connected in series or in parallel is brought close to and electromagnetically coupled to the relay coils. In addition, a loop-shaped reception coil in which a reception system capacitor and a load circuit are connected in series or in parallel is brought close to and electromagnetically coupled to other relay coils, or a load circuit is connected to each of the relay coils in series, or a load circuit is connected to the shared capacitor in parallel. Accordingly, power is wirelessly transmitted from the power supply circuit to the load circuit through the relay cable resonator.

Description

Wireless power transmission system

The present invention relates to a wireless power transmission system that supplies electric power to an electric device across a space.

A wireless power transmission system that feeds power to a power receiving coil that is opposed to a power transmitting coil with a space therebetween can transmit power without contacting the electrode terminal of the power supply device and the electrode terminal of the load device. There is an advantage that the problem of contact failure of the contact point where the contact is made does not occur. Taking advantage of this advantage, wireless power transmission systems are used for toothbrushes and mobile phones.

In order to improve the power transmission efficiency of this wireless power transmission system, in Patent Document 1, the power receiving coil of the load device is coupled to the power transmitting coil connected to the power circuit of the power device by electromagnetic induction. A resonance circuit that resonates with the power supply current of the power supply circuit and a load circuit of the load device are connected to the power receiving coil, and the load device that receives power by the power receiving coil consumes power. The power receiving coil is physically spaced from the power transmitting coil, but both coils are brought close to each other and electromagnetically coupled to transmit power wirelessly. However, in a wireless power transmission system that transmits power from one power transmission coil to one power reception coil, there is a problem that the position of the power reception coil is limited to the vicinity of the power transmission coil in order to perform efficient wireless power transmission. there were.

On the other hand, in Patent Document 2, as a technique for increasing the degree of freedom of the position where the power receiving coil is arranged so that the position of the power receiving coil is not limited to the vicinity of one power transmission coil, a power transmission array is configured with a plurality of power transmission coils. A system has been proposed in which power is transmitted from an array to a receiving coil to increase the degree of freedom of the installation position of the receiving coil.

In Patent Document 3, in order to transmit power to the power receiving coil of the load device at a position away from the power supply device, first, the power transmission coil of the power supply device is opposed to the first relay coil connected to the tip of the relay cable. Then, power is transmitted from the power transmission coil to the first relay coil. Next, the power received by the first relay coil is transmitted by the relay cable to the second relay coil at the end of the relay cable. The power receiving coil of the load device is brought close to and electromagnetically coupled to the second relay coil, and power is transmitted from the second relay coil to the power receiving coil. In this way, in Patent Document 3, the power is transmitted from the power transmission coil of the power supply device to the power reception coil of the load device via the first relay coil, the relay cable, and the second relay coil that relay power transmission. Has been proposed.

JP 2010-011654 A JP 2003-224937 A JP 2013-0666263 A

However, in Patent Document 2, one of a plurality of power transmission coils of a power transmission array is selected by a multiplexer and energized, and the power receiving coil and the power transmission coil are electromagnetically coupled one-to-one to transmit wireless power. Therefore, there is a problem that the electric circuit becomes complicated. Further, in Patent Technology 3, a sufficient solution to the problem of what kind of relay cable should be used to mediate wireless power transmission has not been disclosed.

Therefore, a problem to be solved by the present invention is to provide an appropriate relay cable circuit for mediating wireless power transmission by electromagnetic coupling to a power transmission coil or a power reception coil.

In order to solve this problem, the present invention provides a common capacitor and a plurality of feeder lines that are configured so that the surfaces of two lines face each other in parallel with an interval of one third or less of the width of the line. A loop-shaped relay coil is connected in parallel to form a relay cable resonator, a loop-shaped power transmission coil in which a power transmission system capacity and a power supply circuit are connected in series or in parallel is brought close to the relay coil and electromagnetically coupled, and A loop-shaped power receiving coil, in which a power receiving system capacitor and a load circuit are connected in series or in parallel, is brought close to the other relay coil and electromagnetically coupled, or a load circuit is connected in series to a relay coil, or the shared capacitor A load circuit is connected in parallel to the load circuit, and power is wirelessly transmitted from the power supply circuit to the load circuit via the relay cable resonator.

With this configuration, the present invention has an effect that the inductance of the power supply line pair becomes smaller than the inductance of the relay coil connected to the power supply line pair, and the deterioration of the power transmission characteristics due to the power supply line pair can be prevented.

In addition, the present invention provides a common capacitor and a plurality of loop-shaped relay coils in a pair of feeder lines configured by facing the surfaces of two lines in parallel with an interval of one-third or less of the width of the surface of the line. Are connected in parallel to form a relay cable resonator, a power circuit is connected in series to one of the relay coils, or a power circuit is connected in parallel to the shared capacitor, and the other relay coil is connected to A power receiving system capacitor and a load circuit connected in series or in parallel are brought close to each other and electromagnetically coupled to transmit power from the power supply circuit to the load circuit wirelessly via the relay cable resonator. This is a feature of a wireless power transmission system.

The present invention also provides a shared capacitor resonator in which three or more relay coils are connected in parallel to a shared capacitor, and a loop-shaped power transmission coil in which a power transmission system capacitor and a power circuit are connected in series or in parallel is connected to the relay coil. Close to and electromagnetically coupled to the other relay coil, and close to the loop-shaped power receiving coil in which the power receiving system capacity and the load circuit are connected in series or in parallel, or to be electromagnetically coupled, or to the load coil in series with the relay coil Or a load circuit connected in parallel to the shared capacitor, and wirelessly transmitting power from the power supply circuit to the load circuit via the shared capacitor resonator. is there.

The present invention also comprises a shared capacitor resonator in which two or more relay coils are connected in parallel to the shared capacitor, and a power circuit is connected in series to one of the relay coils, or a power source is connected in parallel to the shared capacitor. A circuit is connected, and a loop-shaped power receiving coil in which a power receiving system capacitor and a load circuit are connected in series or in parallel is brought close to and electromagnetically coupled to the other relay coil, and the shared capacitive resonator is connected from the power circuit. And wirelessly transmitting power to the load circuit.

Also, the present invention is the above-described wireless power transmission system, wherein a part of the surface of the relay coil is arranged so as to overlap a part of the surface of the adjacent relay coil.

Further, the present invention is the above-described wireless power transmission system, characterized in that the shared capacitor is configured by a plurality of capacitors distributed in parallel according to the position of the relay coil and installed in parallel to the relay coil. A wireless power transmission system.

The wireless power transmission system of the present invention uses a pair of power supply lines that are configured by facing the surfaces of two lines parallel to each other, and the distance between the surfaces of the lines of the power supply line pair is set to 3 minutes of the width of the surface of the line. By reducing the inductance of the power supply line pair to be smaller than the inductance of the coil connected to the power supply line pair, it is possible to prevent deterioration of power transmission characteristics due to the power supply line pair.

(A) It is a top view of the receiving coil and power transmission coil of the wireless power transmission system of the 1st Embodiment of this invention. (B) It is a side view of a wireless power transmission system. (C) It is a top view of a relay cable resonator similarly. It is a top view of the receiving coil of the wireless power transmission system of Example 1 of the 1st Embodiment of this invention. It is a graph of S parameter (S21) showing the wireless power transmission efficiency of the simulation result of the wireless power transmission system of Example 1 of this invention. It is a graph showing the frequency characteristic of the input impedance of the circuit seen from the power supply circuit side of the modification 2 of Example 1 of this invention. It is a top view of the relay cable resonator of the 2nd Embodiment of this invention. It is a graph of S parameter (S21) showing the wireless power transmission efficiency of the wireless power transmission system of Example 2 of the 2nd Embodiment of this invention. 4 is an equivalent circuit of the wireless power transmission system according to the first to third embodiments of the present invention. It is a graph showing the frequency characteristic of the input impedance of the circuit seen from the power supply circuit side of the radio | wireless power transmission system of the modification 7 of Example 2 of this invention. It is a graph of S parameter showing the wireless power transmission efficiency of the wireless power transmission system of the modification 8 of Example 2 of this invention. It is the graph of S parameter showing the wireless power transmission efficiency of the 2nd of the modification 8 of Example 2 of this invention. It is a top view of the relay cable resonator of the 4th Embodiment of this invention. It is a graph of S parameter (S21) showing the wireless power transmission efficiency of the wireless power transmission system of Example 3 of the 4th Embodiment of this invention. It is a top view of the relay cable resonator of the 5th Embodiment of this invention. It is a graph of S parameter (S21) showing the wireless power transmission efficiency of the wireless power transmission system of Example 4 of the 5th Embodiment of this invention. It is a top view of the relay cable resonator of the 6th Embodiment of this invention. It is a graph of S parameter (S21) showing the wireless power transmission efficiency of the wireless power transmission system of Example 5 of the 6th Embodiment of this invention.

<First Embodiment>
(Power transmission coil system)
FIG. 1 shows the configuration of the wireless power transmission system according to the first embodiment of the present invention. The diagram on the left side of the plan view of FIG. 1A shows a power transmission coil system in which a loop-shaped power transmission coil LB, a power transmission system capacitor C, and a power supply circuit SC are connected in series. Here, a capacitor for the power transmission system capacitance C is inserted in series between the power transmission coils LB of the power transmission coil system, and the two terminals at the end of the power transmission coil LB are connected to the output terminal of the power supply circuit SC. As a modification of this circuit, the power transmission coil LB can be an antenna with an open end, and the capacity formed between the open ends can be a power transmission system capacity C.

(Receiving coil system)
The right side of the plan view of FIG. 1A shows a power receiving coil system in which a loop-shaped power receiving coil LU, a power receiving system capacitance CU, and a load circuit LD are connected in series. Here, a capacitor for the power receiving system capacitance CU is inserted in series between the power receiving coil LU of the power receiving coil system, and the two terminals at the end of the power receiving coil LU are connected to the two input terminals of the load circuit LD. As a modified example of this circuit, the power receiving coil LU can be an antenna with an open end, and the capacity formed between the open ends can be a power receiving system capacity C.

(Relay cable resonator)
The side view of FIG. 1B shows the configuration of the side arrangement of the power receiving coil LU, the power transmitting coil LB, and the relay cable resonator 1 of the wireless power transmission system. The plan view of the relay cable resonator 1 is shown in the plan view of FIG. The relay cable resonator 1 is configured by connecting a plurality of relay coils in parallel to a shared capacitor CW connected to the feeder line pair LA.

(Relay coil)
Among the plurality of relay coils of the relay cable resonator 1, the relay coil LM1 is the relay coil LM1 that is close to and electromagnetically coupled to the power transmission coil LB, and the relay coil LM2 is the relay coil that is close to and electromagnetically coupled to the power reception coil LU. . The power transmission coil LB and the power reception coil LU are opposed to the relay coils LM1 and LM2 with a coil interval h therebetween.

(Feeding line pair LA)
In FIG. 1C and FIGS. 5, 11, and 13 to be described later, for the convenience of explanation, the feed lines LA1 and LA2 of the feed line pair LA are displayed while being shifted from each other, but the actual feed line LA1 is displayed. And LA2 overlap the surfaces of the belt-shaped feeder line LA1 and the surface of the feeder line LA2 facing each other in parallel without shifting the overlapping region. The interval between the opposing surfaces is at least a narrow interval equal to or less than one third of the width of the belt-like surfaces of the feeder lines LA1 and LA2. In a circuit in which currents flowing in the feeder lines LA1 and LA2 flow in opposite directions by narrowing the distance between the surfaces of the feeder lines LA1 and LA2 to one third or less of the width of the feeder lines LA1 and LA2, This has the effect of reducing the (self) inductance of LA. As a result, the characteristic impedance Z of the power supply line pair LA is reduced.

(Conditions for power supply line pair LA)
With respect to the length len of the feeder line pair LA of the relay cable resonator 1, satisfying the condition of the following formula 1 related to the self-inductance L of the power transmission coil LB and the power receiving coil LU, the power supply lines of the power supply line pair LA are The inductance possessed can be made smaller than the self-inductance L of the power transmission coil LB and the power reception coil LU. Thereby, there is an effect that the influence of the inductance of the feeder line can be reduced.

That is, when the characteristic impedance of the feed line pair LA is Z and the length of the feed line pair LA is len, the inductance of each feed line of the feed line pair LA is the self-inductance L of the power transmission coil LB and the power reception coil LU. The smaller condition is given by Equation 1 below.
(Formula 1) (Z / c) × len <L
Here, c is a signal transmission speed (light speed).

Equation 1 is also valid when there is a dielectric having a predetermined relative permittivity ε _r between the power supply lines LA1 and LA2 of the power supply line pair LA. As its characteristic impedance Z to the influence of the dielectric is reduced by a factor of √Ipushiron _r min when the signal transmission speed c of the feed line pair LA (light velocity) becomes smaller by a factor of √Ipushiron _r min.

By reducing the inductance of the power supply line pair LA by making the distance between the surfaces of the power supply lines LA1 and LA2 of the power supply line pair LA face each other at a narrow distance of 1/3 or less of the surface width, the power transmission coil B and the power reception coil LU Even when a feed line pair LA that is about four times the size of the coil surface is used, there is an effect that the feed line pair LA can have a low inductance that satisfies Equation 1.

(Modification 1)
As a first modification of the feed line pair LA of the first embodiment, a coaxial feed line pair LA configured by concentrically facing the cylindrical surfaces of the cylindrical feed lines LA1 and LA2 in parallel can be used. . By reducing the distance between the surfaces of the feed lines LA1 and LA2 that are coaxially opposed to each other to one third or less of the width of the feed lines LA1 and LA2, that is, the circumferential length of the cylinder, The inductance of LA with respect to LA can be reduced.

Similarly, a coaxial feeder line pair LA having a rectangular cross-sectional shape can be used. Further, the feeder line LA1 is used as the core of a strip-shaped conductor, and the inner surface of the rectangular cylindrical feeder line LA2 surrounding the feeder line LA1 is parallel to the surface of the feeder line LA1, and is not more than one-third of the circumference of the rectangular cylinder. A pair of power supply lines LA facing each other can be formed. Furthermore, a pair of feeder lines LA in which the surfaces of the feeder lines LA1 and LA2 in which a plurality of strip-like surfaces are combined so that the cross section has a comb shape is fitted to each other and the surfaces face each other in parallel are used. it can.

(Shared capacity CW)
In the feeder line pair LA of the relay cable resonator 1, a shared capacitor CW is provided between the feeder line LA1 and the feeder line LA2. Then, two relay coils LM1 and LM2 are connected in parallel to the shared capacitor CW.

Here, the shared capacitor CW is configured by combining a capacitance formed by opposing the surface of the feeder line LA1 and the surface of the feeder line LA2, and a capacitor connected in parallel between the feeder line LA1 and the feeder line LA2. To do. It is sufficient that the capacitor for the shared capacitor CW is connected in parallel between the power supply lines LA1 and LA2 of the power supply line pair LA, and the connection position of the capacitor may be connected between the power supply line pair LA. , It may be connected to the end.

(Principle of relay cable resonator)
The relay cable resonator 1 is configured by connecting a plurality of relay coils in parallel to the shared capacitor CW. In this relay cable resonator 1, a plurality of relay coils share the capacity of the shared capacitor CW and all the relay coils resonate at the same resonance frequency f.

(Inductance LW of the entire relay coil)
The relay cable resonator 1 is represented by a circuit shown at the center of the equivalent circuit of the wireless power transmission system of FIG. 7, and the shared capacitor CW and the plurality of relay coils connected in parallel with each other form a resonance circuit and resonate. The resonance frequency resonates at the resonance frequency f of the resonance circuit constituted by the entire inductance LW of the plurality of relay coils connected in parallel to the shared capacitor CW and the shared capacitor CW. Here, the overall inductance LW of the plurality of relay coils is a set of inductances in which the inductances of the relay coils are connected in parallel, and is smaller than the inductances of the individual relay coils.

イ ン ダ ク タ ン ス The inductances of multiple relay coils connected in parallel to the shared capacitor CW need not be the same value. Even if the inductance of each relay coil has a different value, the inductance LW of the entire relay coil and the shared capacitor CW resonate. That is, even if the relay coils have different self-inductances, the relay coils share the capacity of the shared capacitor CW and all the relay coils resonate at the same resonance frequency f.

In the wireless power transmission system, the power transmission coil LB is brought close to the relay coil LM1 of the relay cable resonator 1 and electromagnetically coupled as shown in the side view of FIG. For example, the two coils are opposed in parallel, and the distance between the two coils is approached with a distance h equal to or less than the diameter of the power transmission coil LB to be electromagnetically coupled. Further, the power receiving coil LU is brought close to the relay coil LM2 of the relay cable resonator 1 to be electromagnetically coupled. For example, the coils are opposed in parallel, and the distance between the coils is electromagnetically coupled with a distance h equal to or less than the diameter of the power receiving coil LU.

The resonance frequency f of the relay cable resonator 1, the resonance frequency f of the power transmission coil system, and the resonance frequency f of the power reception coil system are made equal, and a current of the resonance frequency f is supplied from the power supply circuit SC of the power transmission coil system. The power is transmitted to the coil load circuit LD.

Specifically, when the self-inductance of the power transmission coil LB is LB, the capacity of the power transmission system capacitor C is C, the self inductance of the power reception coil LU is LU, and the capacity of the power reception system capacity CU is CU, The relationship of 2 is satisfied, and the angular frequency ω of the resonance of the coil system is made the same. Here, the angular frequency ω = 2πf (f is the resonance frequency).
(Formula 2) LB × C = LU × CU = LW × CW = 1 / ω ²

(Image impedance)
In the present embodiment, an image impedance inversely proportional to the impedance of the load circuit LD appears in the relay coil LM2 facing the power receiving coil LU, and the image impedance appears in the relay coil LM1 at the other end of the relay cable resonator 1. A second image impedance that is inversely proportional to the image impedance, that is, the impedance of the load circuit LD appears in the power transmission coil LB facing the relay coil LM1. For this reason, the impedance of the load circuit LD appears in the input impedance of the circuit of the wireless power transmission system observed from the power supply circuit SC side.

(Power supply circuit SC)
It is desirable to make the output impedance of the power supply circuit SC equal to the input impedance of the circuit of the wireless power transmission system observed from the power supply circuit SC side in order to match the impedance of the circuit of the wireless power transmission system and transmit power efficiently. .

This condition can also be realized by using a power supply circuit SC using a constant voltage power source or a constant current power source having a sufficiently small output impedance. The reason is that the power supply circuit SC constituted by a constant voltage power supply or a constant current power supply having a sufficiently small output impedance has a power supply circuit having an output impedance equal to the input impedance of the circuit of the wireless power transmission system observed from the power supply circuit SC side. This is because the operation is equivalent.

When the constant voltage power supply having a sufficiently small output impedance is the power supply circuit SC, when the imaginary component (reactance) of the input impedance of the circuit observed from the power supply circuit SC side is sufficiently smaller than the real component, the constant voltage power supply The power supply circuit SC supplies a current inversely proportional to the real component of the input impedance of the circuit. In that case, the power supply circuit SC has an output impedance equal to the input impedance of the circuit, and is equivalent to a power supply circuit in which the internal voltage source has a voltage twice the output voltage. That is, it is equivalent to a power supply circuit whose output impedance is equal to the input impedance of the circuit and whose impedance is matched.

When the imaginary component of the input impedance of the circuit is small, most of the power output from the power supply circuit SC, that is, the product of voltage and current is effective power, and most of the effective power is effectively consumed by the load circuit LD. Is done. Therefore, a constant voltage power source or a constant current power source having a sufficiently small output impedance is used as the power supply circuit SC, and the power circuit SC is used under the condition that the imaginary component (reactance) of the input impedance of the circuit observed from the power circuit SC side is sufficiently smaller than the real component. Thus, there is an effect that the wireless power transmission efficiency of the wireless power transmission system can be improved.

In order to easily control the frequency of the power supply circuit SC that efficiently performs wireless power transmission, the width of the frequency where the imaginary component (reactance) of the input impedance of the circuit is sufficiently smaller than the real component is made as wide as possible. Is desirable. In the following, an embodiment having a load circuit LD having an impedance that satisfies the condition that the imaginary component of the input impedance of the circuit becomes small in a wide frequency range will be mainly described. Even when the load circuit LD has other impedance and the frequency range where the imaginary component of the impedance is small is narrow, wireless power transmission can be efficiently performed by accurately controlling the frequency of the power supply circuit SC within that range. Can do.

(When load circuit LD has rectifier circuit and charging capacitor)
When the load circuit LD is composed of a rectifier circuit and a charging capacitor or capacitor connected to the rectifier circuit, the load circuit LD is considered to operate as follows. In the initial state in which the capacitor for charging the load circuit LD is not charged, the capacitor for charging having a large capacity of the load circuit LD can be regarded as a load having an impedance close to 0 and a small impedance.

Next, when the charging capacitor is charged, the current rectified by the rectifying circuit of the load circuit LD can no longer flow into the charging capacitor, and the charging capacitor of the load circuit LD is considered to have changed to a load having a large impedance. I think I can do it. As described above, since the load of the load circuit LD changes as the charging capacitor is charged, it is desirable to perform control to change the current for charging the charging capacitor accordingly.

(Example 1)
As Example 1 of the first embodiment, as shown in FIG. 1, a relay cable resonator 1, a power transmission coil system configured by connecting a loop-shaped power transmission coil LB, a power transmission system capacitor C, and a power supply circuit SC in series. The operation of the wireless power transmission system composed of a power receiving coil system configured by connecting a loop-shaped power receiving coil LU, a power receiving system capacitance CU, and a load circuit LD in series was investigated by electromagnetic field simulation.

(Power transmission coil LB and power reception coil LU)
In the first embodiment, as shown in FIG. 2, a power receiving coil LU and a power transmitting coil LB are formed of a rectangular one-turn coil having a width of 50 mm and a thickness of 0.2 mm and formed of a copper strip having a side of 350 mm. As the power receiving coil LU, the same power receiving coil LU as that of the first embodiment is used in all the following embodiments, that is, the second embodiment, the third embodiment, the fourth embodiment, and the fifth embodiment. About power transmission coil LB and a relay coil, Example 2, Example 3, and Example 4 use the same power transmission coil LB and relay coil as Example 1. FIG.

In Example 1, the capacity C of the power transmission system capacity C and the capacity CU of the power reception system capacity CU are set to 4.3 nF, and the power transmission coil system and the power reception coil system are resonated at 3.25 MHz.

(Relay cable resonator)
The relay coil LM1 and the relay coil LM2 of the relay cable resonator 1 are formed in the same shape as the power transmission coil LB and the power reception coil LU. The relay coil LM2 and the relay coil LM1 are connected to both ends of a feed line pair LA having a length len = 1450 mm. The feeder line LA1 and the feeder line LA2 constituting the feeder line pair LA are formed by a copper strip having a width of 50 mm and a thickness of 0.2 mm, and the surfaces of the strip-like feeder lines LA1 and LA2 are opposed to each other in parallel. The feeder line pair LA is formed by opening the surface of the feeder line by 80 μm, which is 1/625 of the surface width of 50 mm. In this case, the condition of Formula 1 is satisfied, and the inductance of each feeder line of the feeder line pair LA is sufficiently smaller than the inductance of the relay coil of the relay cable resonator 1.

In the first embodiment, the power supply line pair LA is configured so that the surfaces of the power supply lines LA1 and LA2 face each other with an interval of 80 μm therebetween, so that the capacity formed by the surfaces of the power supply lines LA1 and LA2 facing each other is 8 .3 nF, and the capacity of 8.3 nF is the shared capacity CW. By setting the shared capacitor CW to this value, the resonance frequency of the relay cable resonator 1 is set to 3.25 MHz, which is the same as the resonance frequency of the power transmission coil system and the power reception coil system.

In Example 1, the distance between the power transmission coil LB and the relay coil LM1 of the relay cable resonator 1 and the distance between the relay coil LM2 and the power reception coil LU are set to be 120 mm apart and face each other in parallel. The coupling coefficient k between the coils is 0.2. The coupling coefficient k = 0.2 between the relay coil and the power transmission coil LB and the coupling coefficient k = 0.2 between the relay coil and the power receiving coil LU in the first embodiment are the following second embodiment, third embodiment, and fourth embodiment. But make it the same.

FIG. 3 shows a graph of the frequency characteristic of the wireless power transmission efficiency as a result of the electromagnetic field simulation of the first embodiment. This is a case where the input impedance r2 of the load circuit LD is set to 2.2Ω and the output impedance r1 of the power supply circuit SC is set to 2.2Ω as conditions for widening the frequency range where the wireless power transmission efficiency is high. Attenuation of power transmitted from the power supply circuit SC to the load circuit LD is efficiently transmitted only at −0.06 dB. Further, the frequency width at which this power can be transmitted efficiently is about 0.5 MHz.

(Modification 2) Power supply circuit SC
As a second modification of the first embodiment, a constant voltage power source or a constant current power source having a sufficiently small output impedance r1 of 0.1Ω or less is used for the power supply circuit SC. Here, the input impedance r2 of the load circuit LD is set to 2.2Ω, and the capacity of the power receiving system capacity CU is set to 4.4 nF. FIG. 4 shows a graph of the frequency characteristics of the input impedance obtained by observing the circuit of the wireless power transmission system of Modification 2 from the power supply circuit SC side. The input impedance of this circuit is in the frequency range of 3.14 MHz to 3.34 MHz, and the imaginary number component (reactance) is sufficiently smaller than the real number component. The input impedance of the circuit is 2.3 Ω of the real number, and the resistance Input impedance.

When a power supply circuit SC of a constant voltage power supply having a sufficiently small output impedance r1 is connected to this wireless power transmission system and power of 10 volts is supplied at a frequency of 3.14 MHz or more and 3.34 MHz or less, 10 / A current of 2.3 (A) = 4.3 A flows into the circuit of the wireless power transmission system. The power supply circuit SC supplies 10 × 10 / 2.3 (W) = 43 W of power, and most of the power is efficiently transmitted to the load circuit LD and consumed. The power supply circuit SC of this constant voltage power supply has an output voltage with the same resistance as 2.3 Ω of the resistance input impedance of the circuit of the wireless power transmission system observed from the power supply circuit SC side, and has an internal voltage source of 20 volts. It is equivalent to the power supply circuit SC. Thus, a constant voltage power source or a constant current power source having a sufficiently small output impedance r1 is equivalent to a power source circuit having an output impedance equal to the input impedance of the circuit observed from the power source circuit SC side.

(Modification 3) When the load circuit LD has a rectifier circuit and a charging capacitor In the modification 3 of the first embodiment, the load circuit LD is composed of a rectifier circuit and a charging capacitor connected to the rectifier circuit. In this case, when the resonance frequency of the relay cable resonator 1 and the resonance frequency of the power transmission coil system and the power reception coil system are set to 3.25 MHz, it is considered that the operation is as follows.

In the initial state where the capacitor for charging the load circuit LD is not charged, the capacitor for charging the load circuit LD can be regarded as a load having a small impedance close to zero. The impedance of the load having the small value appears as a second image impedance in the circuit observed from the power supply circuit SC side. When a constant voltage power supply is used for the power supply circuit SC, large power can be supplied by flowing a large current through the impedance of the small value, and a charging capacitor connected to the tip of the rectifier circuit can be quickly charged. There is an effect that can be done.

When the capacitor for charging the load circuit LD is sufficiently charged, the current rectified by the rectifier circuit does not flow into the capacitor for charging, and the load circuit LD can be regarded as a load having a large impedance. The impedance of the load having a large value appears as a second image impedance in the circuit observed from the power supply circuit SC side. The power supply circuit SC desirably performs power supply control to stop a current flowing into the circuit when a large impedance appears in the input impedance of the circuit.

(Modification 4) Feeder line pair LA
As a fourth modification of the first embodiment, the interval between the feeder lines LA1 and LA2 of the feeder line pair LA of the relay cable resonator 1 is set to 1 mm, which is 1/50 of the 50 mm width of the band of the feeder lines LA1 and LA2. Open. In this case, the capacitance between the feeder lines LA1 and LA2 is as small as about 0.6 nF. Therefore, by connecting a capacitor with a capacity of 7.2 nF between the power supply lines LA1 and LA2 in parallel, the shared capacity CW is set to a total capacity of the capacity between the power supply lines LA1 and LA2 and the capacity of the capacitor 7.2 nF. To do. That is, the shared capacity CW is
CW = 7.2nF + 0.6nF = 7.8nF
To. Thereby, the resonance frequency of the relay cable resonator 1 is matched with 3.25 MHz of the resonance frequency of the power transmission coil system and the resonance frequency of the power reception coil system.

In this case, the frequency characteristic of the input impedance of the circuit of the wireless power transmission system observed from the power supply circuit SC side has a real input impedance of about 2.3Ω at a frequency of 3.14 MHz to 3.34 MHz. The result was the same as in the case of 2.

(Modification 5) Power transmission coil system As Modification 5 of the first embodiment, a power transmission coil system is configured by connecting a loop-shaped power transmission coil LB, a power transmission system capacity C, and a power supply circuit SC in parallel. can do. At a frequency near the resonance frequency, a power transmission coil system circuit in which they are connected in parallel is substantially equivalent to a power transmission coil system circuit in which they are connected in series.

(Modification 6) Receiving Coil System As Modification 6 of the first embodiment, the receiving coil system is configured by connecting a loop-shaped receiving coil LU, a receiving system capacitor CU, and a load circuit LD in parallel. can do. At a frequency near the resonance frequency, the receiving coil system circuit in which they are connected in parallel is substantially equivalent to the receiving coil system circuit in which they are connected in series.

<Second Embodiment>
The plan view of the relay cable resonator 1 of the wireless power transmission system of the second embodiment is shown in the plan view of FIG. FIG. 7 shows an equivalent circuit thereof. The second embodiment is different from the first embodiment in that six relay coils are connected in parallel to the shared capacitor CW of the relay cable resonator 1. As in the first embodiment, the shared capacitor CW of the relay cable resonator 1 of the second embodiment is such that the surface of the power supply line LA1 and the surface of the power supply line LA2 that constitute the pair len of the length len are opposite to each other. And the capacitance of the external capacitor connected in parallel with the capacitance.

In FIG. 5, the number of relay coils connected in parallel to the common capacitor CW of the relay cable resonator 1 is six, but the number of relay coils is not limited to this number, and three or more relay coils are shared. What is necessary is just to install in parallel with the capacity | capacitance CW. Each relay coil may be connected to any position of the feed line pair LA, and each relay coil may have a different shape or self-inductance. Even if the relay coils have different self-inductances, the relay coils share the capacity of the shared capacitor CW and all the relay coils resonate at the same resonance frequency, so that wireless power transmission can be performed with high efficiency.

The power transmission coil system and the power reception coil system similar to those of the first embodiment are used, and the power transmission coil LB of the power transmission coil system is brought close to any relay coil of the relay cable resonator 1 in the same manner as in the first embodiment. Then, the power receiving coil LU of the power receiving coil system is brought close to any other relay coil and electromagnetically coupled to perform wireless power transmission.

(Example 2)
The second embodiment will be described below with reference to Example 2. In the second embodiment, as shown in FIG. 5, as the relay cable resonator 1, six relay coils LM1 to LM6 having the same shape as that of the power transmission coil LB and the power reception coil LU are connected in parallel to the feeder line pair LA. The configuration in which the six relay coils in Example 2 are connected in parallel to the feeder line pair LA is the same in Example 3 of the later fourth embodiment, and the same in Example 4 of the fifth embodiment. To do.

The power transmission coil LB of the power transmission coil system is brought close to the relay coil LM1 installed at the end of the power supply line pair LA and electromagnetically coupled with a coupling coefficient k = 0.2. The power receiving coil LU of the power receiving coil system is brought close to one of the remaining five relay coils connected to the power line pair LA, for example, the relay coil LM6 at the end of the power line pair LA, and the electromagnetic coupling is performed with a coupling coefficient k = 0.2. Let In addition, the power transmission system capacity C of the power transmission coil system is set to 4.3 nF, the power reception system capacity CU of the power reception coil system is set to 4.3 nF, and the resonance frequency of the power transmission coil system and the power reception coil system is set to 3.25 MHz.

(Feeding line pair LA)
The feed line pair LA is formed by a feed line LA1 and a feed line LA2 having a length len = 1450 mm. Six relay coils are connected in parallel between the feeder line LA1 and the feeder line LA2. The lines of the feeder line LA1 and the feeder line LA2 are formed of a copper strip having a surface width of 50 mm and a thickness of 0.2 mm. A pair of power supply lines LA is formed with the surfaces of the belt-shaped power supply lines LA1 and LA2 facing each other in parallel and spaced by 29 μm. The configuration of the feeder line pair LA of Example 2 is the same in Example 3 of the fourth embodiment described later, and is the same in Example 4 of the fifth embodiment.

The capacitance CW between the feed lines LA1 and LA2 facing the feed line pair LA is 22.8 nF. When this capacity is set, the resonance frequency of the relay cable resonator 1 becomes 3.25 MHz, which is the same as the resonance frequency of the power transmission coil system and the power reception coil system.

FIG. 6 shows a graph of the frequency characteristics of the wireless power transmission efficiency as a result of the electromagnetic field simulation of the second embodiment. This is a case where the circuit is matched by setting the input impedance r2 of the load circuit LD to 1.25Ω and the output impedance r1 of the power supply circuit SC to 1.25Ω as a condition for widening the frequency range where the wireless power transmission efficiency is good. It is. In the graph of FIG. 6, the power is efficiently transmitted when the attenuation of the power transmitted from the power supply circuit SC to the load circuit LD is only −0.09 dB. The width of the frequency at which power can be transmitted efficiently is about 0.3 MHz.

Further, this configuration is slightly changed, and the relay coil that brings the power receiving coil LU closer is changed from the relay coil LM6 at the end of the power supply line pair LA to the relay coil LM5 at the intermediate position of the power supply line pair LA. The graph of the frequency characteristic of the wireless power transmission efficiency as a result of the electromagnetic field simulation in this case is also a graph of the same frequency characteristic overlapping the graph of FIG.

Further, the relay coil to be electromagnetically coupled by bringing the power transmission coil LB closer to the power transmission coil LB was replaced with the relay coil LM3 at the intermediate position of the feed line pair LA, and the power receiving coil LU was electromagnetically coupled by being brought closer to the relay coil LM5. The graph of the frequency characteristic of the wireless power transmission efficiency as a result of the electromagnetic field simulation in this case is also a graph of the same frequency characteristic overlapping the graph of FIG.

Further, even if the combination of the relay coils of the relay cable resonator 1 that brings the power transmission coil LB and the power reception coil LU close to each other, the same wireless power transmission efficiency graph as the wireless power transmission efficiency graph of FIG. 6 is obtained. There is an effect that wireless power transmission can be performed efficiently.

(Modification 7)
As a modified example 7 of the second example of the second embodiment, a constant voltage power source having an output impedance r1 of 0.1Ω or less and a sufficiently small voltage is applied to the power supply circuit SC as in the modified example 2 of the first example of the first embodiment. Use. Here, the input impedance r2 of the load circuit is set to 1.34Ω. FIG. 8 shows the frequency characteristics of the input impedance of the circuit of the wireless power transmission system observed from the side of the power supply circuit SC in Modification 7. The input impedance of this circuit is a frequency of 3.19 MHz to 3.31 MHz, and has a resistive input impedance of 1.44 Ω whose imaginary number component (reactance) is sufficiently smaller than the real number component.

When a power supply circuit SC of a constant voltage power supply is connected to this circuit, the power supply circuit SC has the same output impedance as the resistance input impedance value of 1.44Ω, and is twice the output voltage to the circuit. Is equivalent to a power supply circuit having an internal voltage source.

<Third Embodiment> (Shared Capacitance Resonator)
Further, the third embodiment is a wireless power transmission system represented by the equivalent circuit of FIG. 7, and includes a shared capacitor resonator having a configuration in which a plurality of relay coils are simply connected in parallel to one shared capacitor CW. The current of all relay coils flowing into the shared capacitor CW is resonated at the same resonance frequency. The equivalent circuit of the wireless power transmission system of the third embodiment remains as in FIG. 7, but a feeder line pair LA having a sufficiently small inductance is used instead of the relay cable resonator 1 of the second embodiment. Use no shared capacitance resonator.

As an example of the shared capacitor resonator, a shared capacitor resonator in which the gap between the feeder lines LA1 and LA2 of the feeder line pair LA of the relay cable resonator 1 is widened to increase the inductance of the feeder lines LA1 and LA2 can be configured. The inductances of the feeder lines LA1 and LA2 become part of the inductance of each relay coil connected to the shared capacitor CW. This shared capacitor resonator is a shared capacitor resonator in which a plurality of relay coils having different inductances are connected in parallel to the shared capacitor CW. In this case as well, all the relay coils resonate at the same resonance frequency and wireless power transmission is performed. Can be performed with high efficiency.

Similarly to the relay cable resonator 1, the shared capacitor resonator is also made close to the relay coil of the shared capacitor resonator and electromagnetically coupled to the power transmitter coil LB and the receiver coil LU, and from the power supply circuit SC to the shared capacitor resonance with the transmitter coil LB. A wireless power transmission system that wirelessly transmits power to the load circuit LD via the power receiver and the receiving coil LU is configured.

In the shared capacitor resonator, it is desirable to connect the three or more relay coils in parallel to the shared capacitor CW to configure the shared capacitor resonator. When the power transmission coil LB is brought close to one relay coil and electromagnetically coupled, the power receiving coil LU can be electromagnetically coupled by bringing the power receiving coil LU close to any of a plurality of other relay coils, thereby providing a degree of freedom in the position of installing the power receiving coil LU. This is to make it higher.

(Modification 8)
As a modification 8 of the second embodiment and the third embodiment, a plurality of power receiving coil systems in which a load circuit LD, a power receiving coil LU, and a power receiving capacity LC are combined are prepared, and the power receiving coils LU of each power receiving coil system are vacant. Close to the relay coil and electromagnetically couple. A wireless power transmission system that wirelessly transmits power in parallel to the power receiving coils LU of the plurality of power receiving coil systems from the power transmitting coil LB connected to the power supply circuit SC via the relay cable resonator 1 or the shared capacitance resonator. Can be configured.

(Example in which power is supplied in parallel to two power receiving coils LU in Modification 8)
As the first of the modification 8 of the second embodiment of the second embodiment, the relay cable resonator 1 is brought close to the relay coil LM1 of the relay cable resonator 1 and electromagnetically coupled to the relay coil LM1 of the power transmission coil system. Supply power. Then, the first power receiving coil LU1 is brought close to and electromagnetically coupled to the relay coil LM5, so that power is wirelessly transmitted from the relay cable resonator 1 to the first power receiving coil LU1.

Further, the power is transmitted wirelessly from the relay cable resonator 1 to the second power receiving coil LU2 by bringing the second power receiving coil LU2 closer to the relay coil LM6 and electromagnetically coupled thereto. Thus, wireless power transmission is performed in parallel to the first load circuit LD1 connected to the first power receiving coil LU1 and the second load circuit LD2 connected to the second power receiving coil LU2.

In this modified example 8, the distance between the power transmission coil LB and the relay coil LM1 is set to be 75 mm opposite to each other. The coupling coefficient k between the coils is k = 0.32. Similarly, the power receiving coil LU1 and the power receiving coil LU2 were electromagnetically coupled with a coupling coefficient k = 0.32 with a spacing of 75 mm between the relay coil LM5 and the relay coil LM6.

When the receiving coil system is only the receiving coil LU1 and no receiving coil LU2 is provided under these conditions, the output impedance r1 of the power supply circuit SC is set to 2Ω and connected to the receiving coil LU1 under the condition of the coupling coefficient k = 0.32. The circuit was matched by setting the input impedance r2 of the load circuit LD to be 2Ω.

When two sets of the receiving coil LU1 and the receiving coil LU2 are inductively coupled to the relay coil of the relay cable resonator 1 under the condition of the coupling coefficient k = 0.32, the output impedance r1 of the power supply circuit SC is 1.6Ω. When the input impedance of the load circuit LD1 connected to the receiving coil LU1 is increased to 3Ω and the input impedance of the load circuit LD2 connected to the receiving coil LU2 is also set to 3Ω, the impedance of the circuit is well matched.

FIG. 9 shows a graph of the frequency characteristics of the wireless power transmission efficiency as a result of electromagnetic field simulation of a circuit having two sets of power receiving coil systems in Modification 8 of Embodiment 2. In FIG. 9, the wireless power transmission efficiency from the power supply circuit SC to the first load circuit LD1 via the relay coil LM5 of the relay cable resonator 1 is indicated by S51, and the relay of the relay cable resonator 1 from the power supply circuit SC. The wireless power transmission efficiency to the second load circuit LD2 via the coil LM6 is indicated by S61.

In FIG. 9, S51 and S61 each have a transmission efficiency of minus 3 dB, half of the power from the power supply circuit SC is transmitted to the first load circuit LD1, and the remaining power is transmitted to the second load circuit LD2. The In this way, it is possible to configure a wireless power transmission system that can efficiently transmit power by half from the power supply circuit SC to the two parallel load circuits LD via the relay cable resonator 1.

(Example in which power is supplied in parallel to the three power receiving coils LU in Modification 8)
As the second modification 8 of the second embodiment of the second embodiment, the relay coils LM4, LM5, and LM6 of the relay cable resonator 1 are respectively connected to the first power receiving coil LU1, the second power receiving coil LU2, and the second power receiving coil LU2. The second power receiving coil LU3 connected to the first power receiving coil LU1 and the second power receiving coil LU2 are connected from the relay cable resonator 1 to the second power receiving coil LU2 by approaching and electromagnetically coupling the three power receiving coils LU3. The power is wirelessly transmitted to the load circuit LD2 and the third load circuit LD3 connected to the third power receiving coil LU3. In this embodiment, there are three sets of receiving coil systems, the output impedance r1 of the power supply circuit SC is further lowered to 1.4Ω, and the input impedances of the load circuits LD1, LD2 and LD3 are increased to 4.5Ω, respectively. The impedance matched well.

FIG. 10 shows a graph of frequency characteristics of the wireless power transmission efficiency as a result of electromagnetic field simulation of a circuit having three sets of receiving coil systems in the modified example 8 of the second embodiment. In FIG. 10, the wireless power transmission efficiency from the power supply circuit SC to the first load circuit LD1 via the relay coil LM4 of the relay cable resonator 1 is indicated by S41, and the relay of the relay cable resonator 1 from the power supply circuit SC. The wireless power transmission efficiency to the second load circuit LD2 via the coil LM5 is indicated by S51, and the wireless power transmission from the power supply circuit SC to the third load circuit LD3 via the relay coil LM6 of the relay cable resonator 1 The efficiency is indicated by S61.

In FIG. 10, S41, S51, and S61 each have a transmission efficiency of minus 5 dB, and one third of the power from the power supply circuit SC is the first load circuit LD1, the second load circuit LD2, and the third To the load circuit LD3. In this way, a wireless power transmission system that can efficiently transmit power by one third wirelessly from the power supply circuit SC to the three parallel load circuits LD via the relay cable resonator 1 can be configured.

<Fourth Embodiment>
The relay cable resonator 1 of the wireless power transmission system of the fourth embodiment is shown in the plan view of FIG. The wireless power transmission system of the fourth embodiment is different from that of the second embodiment in that one relay coil LM1 among the plurality of relay coils of the relay cable resonator 1 is shared with the power transmission coil LB and the power supply circuit SC. Is connected to the relay coil LM1 in series. In this case, a part of the shared capacity CW is used as the power transmission system capacity C to be connected to the shared power transmission coil LB. Other configurations are the same as those of the second embodiment.

(Example 3)
The fourth embodiment will be described below with reference to Example 3. As shown in FIG. 11, the power supply circuit SC is connected in series to the relay coil LM1 connected to the end of the feeder line pair LA. The other five relay coils are referred to as relay coils LM2, LM3, LM4, LM5, and LM6. The power receiving coil LU of the power receiving coil system is brought close to any one of the relay coils and electromagnetically coupled with a coupling coefficient k = 0.2 to perform wireless power transmission. The receiving system capacitance CU of the receiving coil system is set to 4.4 nF, and the resonance frequency of the receiving coil system is set to 3.25 MHz.

FIG. 12 shows a graph of the frequency characteristics of the wireless power transmission efficiency as a result of the electromagnetic field simulation of the third embodiment. This is a case where the power receiving coil LU is electromagnetically coupled to the relay coil LM6 at the end of the feeder line pair LA of the relay cable resonator 1 with a coupling coefficient k = 0.2. In this case, when the input impedance r2 of the load circuit LD is set to 0.7Ω and the output impedance r1 of the power supply circuit SC is set to 8Ω which is larger than the input impedance r2 of the load circuit LD, the circuit is well matched.

In the graph of FIG. 12, the attenuation of power transmitted from the power supply circuit SC to the load circuit LD via the relay cable resonator 1 and the power receiving coil LU is about −0.08 dB, and wireless power transmission with high efficiency can be performed. The frequency range with good power transmission efficiency is about 0.2 MHz.

Further, the power receiving coil LU was brought close to and electromagnetically coupled to the relay coil LM5 in the middle position of the feeder line pair LA of the relay cable resonator 1. The graph of the frequency characteristic of the wireless power transmission efficiency as a result of the electromagnetic field simulation in this case is the same graph as the graph of FIG. Further, the power receiving coil LU was brought close to the relay coil LM2 and electromagnetically coupled. In this case, the graph of the frequency characteristic of the wireless power transmission efficiency is almost the same as that in FIG.

(Modification 9)
As a ninth modification of the third embodiment, similarly to the second modification of the first embodiment of the first embodiment and the seventh modification of the second embodiment of the second embodiment, the output impedance of the power supply circuit SC is sufficiently small. Use a constant voltage power supply. Then, by electromagnetic field simulation, a condition that the imaginary component (reactance) of the input impedance of the entire circuit including the power transmission coil system and the power reception coil system, observed from the power supply circuit SC side, is set to 0 over as wide a frequency range as possible. Asked.

In the modified example 9, if the input impedance r2 of the load circuit LD is 1.1Ω and the capacitance CU of the power receiving system capacitor CU is 4.5 nF, the imaginary component of the input impedance of the entire circuit observed from the power supply circuit SC side is It became 0 stably in the frequency range of 3.1 MHz to 3.5 MHz.

At that time, the real component of the input impedance of the entire circuit observed from the power supply circuit SC side varied between 8Ω and 3Ω. Although the value of the real component is not a constant value, the power supply circuit SC is equivalent to a power supply circuit that outputs power with the same real value output impedance r1 as the real component in the frequency range, and the power supply circuit SC outputs Thus, it is possible to perform good wireless power transmission in which all the power is effectively consumed by the load circuit LD.

(Modification 10)
As a tenth modification of the wireless power transmission system of the fourth embodiment, among the plurality of relay coils connected in parallel to the shared capacitor CW in the shared capacitor resonator of the third embodiment shown by the equivalent circuit of FIG. A wireless power transmission system in which one is shared with the power transmission coil LB and connected in series to the power supply circuit SC can be configured.

<Fifth Embodiment>
The relay cable resonator 1 of the wireless power transmission system of the fifth embodiment is shown in the plan view of FIG. The fifth embodiment differs from the second embodiment to the fourth embodiment in that the power supply circuit SC is electrically connected in parallel to the shared capacitor CW between the feed lines LA1 and LA2 of the feed line pair LA. It is. As in the second embodiment, the power receiving coil LU of the power receiving coil system including the load circuit LD is brought close to the relay coil LM6 and electromagnetically coupled to transmit power wirelessly. The configuration of the fifth embodiment is characterized in that the output impedance of the power supply circuit SC for matching the impedance of the circuit is increased.

Example 4
Hereinafter, the fifth embodiment will be described by Example 4. As shown in FIG. 13, the power supply circuit SC is connected to the feeder line pair LA. Then, the power receiving coil LU of the power receiving coil system is brought close to any one of the relay coils and electromagnetically coupled with a coupling coefficient k = 0.2 to transmit power wirelessly. The capacity CU of the power receiving system CU of the power receiving coil system is set to 4.3 nF, and the resonance frequency of the power receiving coil system is set to 3.25 MHz.

FIG. 14 shows a graph of the frequency characteristics of the wireless power transmission efficiency of Example 4. Here, the power receiving coil LU is brought close to the relay coil LM6 at the end of the feeder line pair LA of the relay cable resonator 1 and electromagnetically coupled with a coupling coefficient k = 0.2. In this case, the input impedance r2 of the load circuit LD is set to 1Ω, and the output impedance r1 of the power supply circuit SC is increased to 28Ω, that is, the input impedance r2 of the load circuit LD is set larger than 1Ω to improve the circuit impedance. Consistent.

The wireless power transmission efficiency is also good in the graph of FIG. In addition, the frequency range for efficient wireless power transmission is about 0.2 MHz.

In Example 4, when the input impedance r2 of the load circuit LD was set to 0.5Ω smaller than 1Ω, the output impedance r1 of the appropriate power supply circuit SC was also reduced to 23Ω to match the impedance of the circuit. When the input impedance r2 of the load circuit LD is further reduced to 0.2Ω, the output impedance r1 of the power supply circuit SC for matching the impedance of the circuit is also reduced to 6Ω.

(Modification 11)
As a modification 11 of the wireless power transmission system of the fifth embodiment, in the shared capacitor resonator of the third embodiment shown by the equivalent circuit in FIG. 7, a power supply circuit SC is connected in parallel to the shared capacitor CW, and the shared capacitor A wireless power transmission system that wirelessly transmits power from the power supply circuit SC to the load circuit LD can be configured by causing the power receiving coil LU to approach and electromagnetically couple to one of the relay coils of the resonator. In the shared capacitance resonator of the modification 11, it is desirable to configure a shared capacitance resonator by connecting two or more relay coils in parallel to the shared capacitance CW. This is because providing two or more relay coils for electromagnetically coupling the power receiving coil LU close to each other can provide a degree of freedom in the position where the power receiving coil LU is installed.

(Modification 12)
As a modification 12 of the fourth embodiment of the fifth embodiment, as in a modification 8 of the second embodiment of the second embodiment, a plurality of power receiving coils are supplied from the relay cable resonator 1 fed with power from the power supply circuit SC. For example, power is supplied in parallel to the two load circuits LD1 and LD2 to the system load circuit.

In the twelfth modified example, the gap between the relay coil and the power receiving coil LU1 of the power receiving coil system and the relay coil LM5 is opposed to each other in parallel by 75 mm and electromagnetically coupled with a coupling coefficient k = 0.32. Similarly, the gap between the power receiving coil LU2 and the relay coil LM6 is made 75 mm opposite to be electromagnetically coupled with a coupling coefficient k = 0.32.

In this case, when the power receiving coil system is only the power receiving coil LU1 and the power receiving coil LU2 is not provided, when the input impedance r2 of the load circuit LD connected to the power receiving coil LU1 is 1.4Ω, the output of the power circuit SC The impedance of the circuit is well matched by setting the impedance r1 to 18Ω.

Here, when the power receiving coil to be inductively coupled to the relay coil of the relay cable resonator 1 is the power receiving coil LU1 and the power receiving coil LU2, the input impedance of the load circuit LD1 connected to the power receiving coil LU1 is 1.4Ω. The input impedance of the load circuit LD2 connected to the power receiving coil LU2 is also set to 1.4Ω, and the output impedance r1 of the power supply circuit SC is lowered to 10Ω so that the impedance of the circuit is well matched.

<Sixth Embodiment>
The plan view of the relay cable resonator 1 of the wireless power transmission system of the sixth embodiment is shown in the plan view of FIG. Similar to the fourth embodiment, the sixth embodiment uses a relay cable resonator 1 having a configuration in which the relay coil LM1 is shared with the power transmission coil LB and the power supply circuit SC is connected in series to the relay coil LM1. This embodiment is different from the fourth embodiment in that a part of the coil surfaces of the relay coils LM2 to LM14 are arranged so as to overlap a part of the surface of the adjacent relay coil.

In FIG. 15, the feed lines LA1 and LA2 of the feed line pair LA are displayed as two parallel lines as a conceptual diagram. However, the actual feed lines LA1 and LA2 are the same as those in the fourth embodiment, the second embodiment, and the second embodiment. As in the case of the first embodiment, it is a strip of a conductor having a length of len that is opposed to each other with an interval of 1/3 or less of the width of the surface of the feeder line. And the capacity | capacitance formed by the feed lines LA1 and LA2 of the feed line pair LA facing each other and the capacity of the capacitor connecting both the feed lines are connected in parallel to form a shared capacity CW.

This relay cable resonator 1 has a plurality of relay coils LM1 to LM14 connected in parallel to the shared capacitor CW as shown in FIG. A power supply circuit SC is connected in series to the relay coil LM1. Other than that, the relay coils LM2 to LM14 in which a part of the coil surface overlaps each other, the power receiving coil LU having the same configuration as that of the first embodiment is brought close to and electromagnetically coupled to transmit power wirelessly.

In the sixth embodiment, a part of the coil surface of the relay coils LM2 to LM14 is arranged so as to overlap with a part of the surface of the adjacent relay coil. With this configuration, the power receiving coil LU is electromagnetically coupled to face the plurality of relay coils. The power receiving coil LU brought close to the plurality of relay coils does not change the graph of the frequency characteristic of the wireless power transmission efficiency even if it is moved from position A to position B in FIG. There is an effect that wireless power transmission can be performed.

(Example 5)
Hereinafter, the sixth embodiment will be described with reference to Example 5. As shown in FIG. 15, all the relay coils LM1 to LM14 are connected in parallel to the shared capacitor CW. The power supply circuit SC is connected in series to the relay coil LM1 to supply power. The relay coil groups of the relay coils LM2 to LM14 of the relay cable resonator 1 are arranged such that a part of the surface (coil surface) surrounding the relay coil is overlapped with a part of the surface of the adjacent relay coil. The power receiving coil LU is brought close to a plurality of relay coils in the relay coil group and electromagnetically coupled to transmit power wirelessly.

The shape of the receiving coil LU is the same as that of the first embodiment, and a rectangular receiving coil LU having a side of the coil surface of 350 mm is used. A power receiving system capacitor CU and a load circuit LD are connected in series to the power receiving coil LU. The capacity CU of the power receiving system capacity CU connected to the power receiving coil LU is set to 4.4 nF, and the resonance frequency of the power receiving coil system is set to 3.25 MHz.

The pair of feeder lines LA is formed by facing copper strip-like feeder lines LA1 and LA2 having a width of 50 mm and a length of 3.9 m in parallel with an interval of 1 mm. A capacitor having a capacitance of 5.8 nF was connected as a shared capacitor CW between the feeder lines LA1 and LA2 of the feeder line pair LA. The relay cable resonator 1 is configured by connecting the relay coils LM1 to LM14 in parallel to the shared capacitor CW. The resonance frequency of the relay cable resonator 1 substantially matches the resonance frequency of 3.25 MHz of the power transmission coil system and the power reception coil system.

The relay coil LM1 of the relay cable resonator 1 was formed of a rectangular one-turn coil having a dimension of a surface of a coil of 875 mm × 550 mm formed of a copper strip having a width of 25 mm and a thickness of 0.2 mm. The relay coils LM2 to LM14 were formed of a rectangular one-turn coil having a coil surface width of 875 mm × 825 mm and formed of a copper strip having a coil wiring width of 25 mm and a thickness of 0.2 mm. In the relay coils LM2 to LM14, a part of the wiring of the coil is carried by the power supply line pair LA. The relay coils LM2 to LM14 were superposed on each other by shifting by 225 mm, which is a quarter of the length of the coil surface of the relay coil 875 mm, in the direction of the feed line pair LA.

In this way, since the relay coils LM2 to LM14 are shifted by 225 mm and arranged so that the surfaces of the coils are overlapped, the rectangular power receiving coil LU whose one side of the coil is 350 mm faces the five to six relay coils, Of these, two to three relay coils are completely surrounded. Even if the power receiving coil LU is moved from position A to position B in FIG. 15 by 1400 mm, the number of coupling systems between the relay coil group of the relay cable resonator 1 and the power receiving coil LU is hardly changed.

FIG. 16 shows a graph of the frequency characteristics of the wireless power transmission efficiency as a result of the electromagnetic field simulation of the fifth embodiment. This graph shows a case where the power receiving coil LU is installed between the position A or the position B of the relay cable resonator 1 and its position. In this simulation, as conditions for widening the frequency range where the wireless power transmission efficiency is high, the input impedance r2 of the load circuit LD is set to 0.8Ω, and the output impedance r1 of the power supply circuit SC is set to 15Ω so that the circuits are well matched.

In the graph of FIG. 16, the width of the frequency with high wireless power transmission efficiency is approximately the same as that of the third embodiment. And between the position A to the position B in FIG. 15 where the power receiving coil LU is installed, there is an effect that the graph of the frequency characteristic of the wireless power transmission efficiency hardly changes even if the position of the power receiving coil LU is changed.

(Comparative Example 1)
As Comparative Example 1 compared with Example 5, the relay cable resonator 1 is provided with only the relay coil LM1 shared with the power transmission coil LB and the relay coil LM11, and the power receiving coil LU is surrounded only by the relay coil LM11. . The wireless power transmission system using the relay cable resonator 1 of Comparative Example 1 was subjected to electromagnetic field simulation, and a graph of frequency characteristics was calculated. As a result, the graph of the frequency characteristic of the wireless power transmission efficiency of Comparative Example 1 is the same as that of Example 5, and the position of the power receiving coil LU for efficiently transmitting power wirelessly is the relay coil LM11 with dimensions of 875 mm × 825 mm. It has been found that the power receiving coil LU is limited to a position that is completely surrounded. That is, the degree of freedom of the position of movement of the power receiving coil LU within the range of Comparative Example 1 was about 475 mm.

Compared to the comparative example 1, in the relay cable resonator 1 of the fifth embodiment, the degree of freedom of movement of the position of the power receiving coil LU is wireless even if the large distance of 1400 mm from the position A to the position B in FIG. The graph of the frequency characteristic of the power transmission efficiency did not change, and there was an effect that the degree of freedom of the movement position of the power receiving coil LU was three times larger.

Further, if the length of the relay coil LM11 of the comparative example 1 is increased to about the length of the coil surface of the entire relay coil group of the fifth embodiment, the degree of freedom of movement of the position of the power receiving coil LU can be increased even in the comparative example 1. The size can be increased as in the fifth embodiment. However, in that case, in Comparative Example 1, there is a problem that, as the coil of the relay coil LM11 is increased, the magnetic field leaking to the outside of the coil increases and the radiation noise leaking to the outside environment increases. On the other hand, in the relay coil group of the fifth embodiment, the current flows only through the relay coil near the power receiving coil LU. Therefore, the length of the coil surface of the entire relay coil group is increased to move the position of the power receiving coil LU. Even if the degree of freedom is increased, the magnetic field leaking out of the coil does not increase.

(Effect of common mode current flowing in the power supply line pair LA)
In the sixth embodiment, the feeder line pair LA constitutes a part of the coils of the relay coils LM2 to LM14. Therefore, when the resonance current of the relay coil LM2 flows through the relay coil, a common mode current that is a current in phase flows through the feeder lines LA1 and LA2 as part of the relay coil LM2 through a part of the feeder line pair LA. . In the portion where the common mode current flows, the feeder line pair LA exhibits a self-inductance with respect to the current, and a part of the self-inductance of the relay coil LM2 is formed.

However, the power supply line pair LA has a self-inductance that cannot be ignored because the resonance current of the individual resonance circuit of each relay coil is common to the power supply lines LA1 and LA2 of the power supply line pair LA used as a part of the relay coil. Only when mode current flows. Therefore, since the power supply line pair LA supplies power to the resonance circuit of each relay coil, the self-inductance does not appear in the circuits that cause currents to flow in the opposite directions to the power supply lines LA1 and LA2. It does not become an obstacle to supplying power to the resonance circuit of the relay coil.

(Distributed installation of shared capacity CW)
In the present embodiment, since the self-inductance appears in the portion where the resonance circuit of the relay coil passes the common mode current to the feeder line pair LA, each of the relay coils LM2 to LM14 has the portion of the shared capacitor CW for constituting the resonance circuit. It is desirable to install in the vicinity of the relay coils LM2 to LM14. For this purpose, it is desirable to disperse the shared capacitor CW connecting the power supply lines LA1 and LA2 for each position of the relay coils LM2 to LM14 to a plurality of parallel capacitors and to install them in the power supply line pair LA at the position of each relay coil. . Each capacitor in which the shared capacitor CW is dispersed is not necessarily provided for each relay coil, but one capacitor may be provided for each relay coil in the feeder line pair LA.

(Modification 13)
As a modified example 13, in the wireless power transmission system of the sixth embodiment, the power supply circuit SC can be connected in parallel to the shared capacitor CW of the relay cable resonator 1 as in the fifth embodiment. Similarly to the second embodiment, the power transmission coil LB of the power transmission coil system to which the power supply circuit SC is connected can be brought close to one of the relay coils to be electromagnetically coupled to supply power from the power supply circuit SC wirelessly.

(Modification 14)
As a modification 14, the wireless power transmission system of the sixth embodiment can be configured as a shared capacitance resonator having the same configuration as that of the third embodiment. That is, a shared capacitor resonator in which a plurality of relay coils are simply connected in parallel to the shared capacitor CW can be applied. In that case, a power supply line pair LA composed of power supply lines LA1 and LA2 is necessary to connect the relay coil group, and the self-inductance of the power supply line pair LA cannot be ignored. It is desirable to install a plurality of capacitors that distribute CW to the feeder line pair LA.

It should be noted that the present invention is not limited to the embodiment described above, and a wireless power transmission system having a circuit configuration in which the power supply circuit SC and the load circuit LD are replaced in the circuit of the above embodiment can also be configured.

The present invention can be applied to an application in which inductive energy is supplied across a desk plate to an electronic device installed on a desk. Further, the present invention can be applied to an application for supplying electric power to a vehicle or the like from a power supply facility in a contactless manner. Further, the present invention can be applied to an application in which electric power or an electric signal is transmitted in a non-contact manner between wiring layers of an integrated circuit within a semiconductor integrated circuit.

DESCRIPTION OF SYMBOLS 1 ... Relay cable resonator, C ... Power transmission system capacity, CU ... Power reception system capacity, CW ... Shared capacity, f ... Frequency, h ... Coil interval, LA ... Supply Wire pair, LA1, LA2 ... feed line, LB ... power transmission coil, LD ... load circuit,
LM1, LM2, LM3, LM4, LM5, LM6, LM7, LM8, LM9, LM10, LM11, LM12, LM13, LM14 ... Relay coil, LU ... Power receiving coil, r1 ... Output impedance of power supply circuit, r2: input impedance of load circuit, SC: power supply circuit

Claims (6)

1. A common capacitor and a plurality of loop-shaped relay coils are connected in parallel to a pair of feeders configured such that the surfaces of two lines face each other in parallel with an interval of 1/3 or less of the width of the line. A relay cable resonator is configured, and a loop-shaped power transmission coil in which a power transmission system capacitor and a power supply circuit are connected in series or in parallel is brought close to the relay coil and electromagnetically coupled. A power receiving circuit in which a loop-shaped power receiving coil connected in series or in parallel with a load circuit is approached and electromagnetically coupled, or a load circuit is connected in series with a saddle relay coil, or a load circuit is connected in parallel with the shared capacitor To wirelessly transmit power to the load circuit via the relay cable resonator.
2. A common capacitor and a plurality of loop-shaped relay coils are connected in parallel to a pair of feeders configured such that the surfaces of two lines face each other in parallel with an interval of 1/3 or less of the width of the line. A relay cable resonator is configured, a power circuit is connected in series to one of the relay coils, or a power circuit is connected in parallel to the shared capacitor, and a power receiving system capacitor and a load circuit are connected to the other relay coil. Wireless power transmission, wherein a loop-shaped power receiving coil connected in series or in parallel is brought close to and electromagnetically coupled, and power is wirelessly transmitted from the power supply circuit to the load circuit via the relay cable resonator system.
3. A shared capacity resonator is formed by connecting three or more relay coils in parallel to the shared capacity, and a loop-shaped power transmission coil in which a power transmission system capacitor and a power circuit are connected in series or in parallel is brought close to the relay coil and electromagnetically coupled. In addition, a loop-shaped power receiving coil in which a power receiving system capacity and a load circuit are connected in series or in parallel is brought close to the other relay coil and electromagnetically coupled, or a load circuit is connected in series to the saddle relay coil, or A wireless power transmission system, wherein a load circuit is connected in parallel to a shared capacitor, and power is wirelessly transmitted from the power supply circuit to the load circuit via the shared capacitor resonator.
4. A shared capacitor resonator in which two or more relay coils are connected in parallel to the shared capacitor, a power circuit is connected in series to one of the relay coils, or a power circuit is connected in parallel to the shared capacitor; and In addition, a loop-shaped power receiving coil in which a power receiving system capacitor and a load circuit are connected in series or in parallel is brought close to and electromagnetically coupled to the other relay coil, and the load circuit is connected from the power supply circuit via the shared capacitive resonator. A wireless power transmission system characterized by transmitting power wirelessly.
5. The wireless power transmission system according to any one of claims 1 to 4, wherein a part of the surface of the relay coil is arranged so as to overlap a part of the surface of the adjacent relay coil. Transmission system.
6. 6. The wireless power transmission system according to claim 5, wherein the shared capacitor is composed of a plurality of capacitors distributed in parallel according to the position of the relay coil and installed in parallel to the relay coil. system.

Images