JP6858151B2 - Wireless power supply device and its impedance adjustment method - Google Patents

Description

The present invention relates to a wireless power feeding device that wirelessly (wirelessly, non-contactly) transmits power by utilizing electric field coupling (including electric field resonance) or magnetic field coupling (including magnetic field resonance).

Technology for supplying energy wirelessly is being actively researched. The wireless power feeding method mainly includes an electromagnetic induction method, an electromagnetic field resonance method (general term for electric field resonance and magnetic field resonance), and an electric field coupling method.

For example, the electromagnetic field resonance method includes a power supply unit that supplies AC power, a coupler unit that wirelessly transmits power, and a load to which power received is supplied via the coupler unit. Further, the coupler unit includes a power transmission coupler that transmits the AC power supplied from the power supply unit to the power receiving side, and a power receiving coupler that receives the AC power transmitted from the power transmission coupler.

The power transmission coupler includes a power transmission LC circuit that resonates at the frequency of the supplied AC power, and the power reception coupler includes a power reception LC circuit that receives AC power from the power transmission LC circuit. When the power receiving LC circuit resonates or resonates with an electric field, the AC power of the frequency component that resonates with the LC can be wirelessly transmitted. Here, the electric field resonance method uses the electric field resonance between the capacitors (electrodes, etc.) of the power transmission / reception LC circuit, and the magnetic field resonance method uses the magnetic field resonance between the inductors (coils, etc.).

In the electromagnetic field resonance type wireless power supply, if the input / output impedances of the power supply unit, the coupler unit, and the load are matched, power transmission with high power supply efficiency is performed. However, in the current electromagnetic field resonance type wireless power supply, the impedance of the coupler section changes depending on the distance between the couplers for power transmission and the coupler for power reception. For example, the distance between the couplers for power transmission and the coupler for power reception deviates from the design value, resulting in impedance mismatch. In addition, impedance mismatch may occur due to load fluctuations. For example, if the load is a battery, it becomes difficult for current to flow through the circuit as charging progresses. When the battery is empty, the impedance is low, and when the battery is almost fully charged, the impedance is high. In this way, impedance mismatch has been caused by various causes at present.

Therefore, various impedance matching methods for wireless power feeding devices have been proposed. The resonance conditions of the LC circuit are determined by the frequency, inductance and capacitance. Therefore, for example, a method of impedance matching by changing the capacitance of the LC circuit has been proposed. In Patent Document 1, the resonance capacitance of the transmitting side resonator is configured by a variable capacitor, and the resonance frequency characteristic of the transmission resonance system composed of the transmitting side resonator and the receiving side resonator is used to determine the capacitance of the variable capacitor during power transmission. A magnetic resonance type wireless power feeding device has been proposed in which the peak of the resonance frequency characteristic is adjusted so as to match the frequency of the power to be fed. Further, in an electromagnetic induction type wireless power feeding device used in a low frequency band, a method of controlling the phase of a switching power supply for matching has also been proposed.

Japanese Unexamined Patent Publication No. 2013-85350

However, in the wireless power feeding device described in Patent Document 1, a variable capacitor called a variable capacitor is used as the resonance capacitance of the power transmitting side resonator. Since the variable capacitor mechanically changes between the electrodes, there is a problem that the response is slow. There is also a problem that the life is short and the reliability is poor. Further, in the electromagnetic field resonance type wireless power feeding using a high frequency of MHz or higher, it is very difficult to control the phase in a short time.

Therefore, the present invention has been made to solve the above problems, and it is possible to change the inductance of the power transmission LC circuit and / or the power reception LC circuit according to the state of power transmission. It is an object of the present invention to provide a power feeding device.

In order to achieve the above object, the first aspect of the wireless power feeding device of the present invention includes a power transmitting coupler having a power transmitting LC circuit and a power receiving coupler having a power receiving LC circuit, and the power transmitting LC circuit. And the power receiving LC circuit are wireless power feeding devices that wirelessly transmit power from the power transmitting coupler to the power receiving coupler by an electric field or a magnetic field, and electrically to at least one of the power transmitting LC circuit and the power receiving LC circuit. The adjusting coil connected to the adjusting coil, the variable inductance portion including the adjusting coil and capable of changing the inductance of the adjusting coil, and the inductance of the adjusting coil of the variable inductance portion are changed according to the state of the power transmission. It is characterized by having an impedance adjusting unit.

In another aspect of the wireless power feeding device of the present invention, the variable inductance unit outputs a DC current to the inductance variable circuit in which the inductance of the adjusting coil changes based on the input DC current and the inductance variable circuit. A working circuit for operating the variable inductance circuit is provided, and the impedance adjusting unit is characterized in that it controls a direct current output to the variable inductance circuit.

In another aspect of the wireless power feeding device of the present invention, the variable inductance circuit has a magnetic core formed of a magnetically saturated magnetic material and the adjustment formed so as to wind a main winding around the magnetic core. The magnetic core is provided with a coil and a control coil formed so as to wind a control winding around the magnetic core, and when a DC current is input from the control winding, the magnetic core responds to the input DC current. It is characterized by changing the magnetic permeability of.

Another aspect of the wireless power feeding device of the present invention is characterized in that the magnetic path is formed in a closed circuit in the magnetic core.

In another aspect of the wireless power feeding device of the present invention, the magnetic material core includes a first magnetic material core portion and a second magnetic material core portion, and the first magnetic material core portion and the second magnetic material. The third magnetic core portion arranged between the core portions, the first magnetic core portion, the third magnetic core portion, and the second magnetic core portion are connected from one or the other, respectively. The control coil has a first magnetic core connection portion and a second magnetic core connection portion, and the control coil is formed so as to wind the control winding around the third magnetic core portion, and the adjustment coil is formed. Is formed so as to wind a first main winding and a second main winding around the first magnetic core portion and the second magnetic core portion, respectively, and the first main winding and the said It has a first main coil and a second main coil formed so that the magnetic fields excited in the second main winding are opposite to each other, and the first magnetic core connection portion and the second magnetic core connection. The first main coil, the second main coil, and the control coil are arranged between each other, and the first magnetic core portion, the third magnetic core portion, and the second magnetic portion are arranged. It is characterized by connecting the body core part.

Another aspect of the wireless power feeding device of the present invention is characterized in that the magnetic core is an annular core.

Another aspect of the wireless power feeding device of the present invention is characterized in that the magnetic core is a columnar core.

In another aspect of the wireless power feeding device of the present invention, the operating circuit is provided between a directional coupler arranged in a transmission path through which alternating reflected power is transmitted, and between the directional coupler and the variable inductance circuit. A rectifying unit is provided, the directional coupler branches the reflected power and outputs the reflected power to the rectifying unit, and the rectifying unit transfers the reflected power input from the directional coupler to a direct current. It is characterized in that it is rectified to and output to the variable inductance circuit.

Another aspect of the wireless power feeding device of the present invention is characterized in that the operating circuit outputs a direct current from a constant current source to the variable inductance circuit.

Another aspect of the wireless power feeding device of the present invention is characterized in that the operating circuit rectifies AC power input from a power supply unit into DC power and outputs the AC power to the variable inductance circuit.

In another aspect of the wireless power feeding device of the present invention, the variable inductance portion is formed by the adjusting coil formed so as to wind a winding and a magnetic material that is magnetically saturated and inserted into the adjusting coil. It is characterized by including a cylindrical magnetic core and a position adjusting portion that changes the inductance of the adjusting coil by changing the relative positions of the adjusting coil and the magnetic core.

Another aspect of the wireless power feeding device of the present invention includes a first voltage detection circuit that detects the voltage of the AC transmission power transmitted by the transmission coupler, and a first current detection circuit that detects the current of the transmission power. A second voltage detection circuit for detecting the voltage of the AC received power received by the power receiving coupler and a second current detection circuit for detecting the current of the received power are provided, and the impedance adjusting unit is described as described above. The voltage and current of the transmitted power and the voltage and current of the received power detected by the first voltage detection circuit, the first current detection circuit, the second voltage detection circuit and the second current detection circuit are input and input. It is characterized in that the DC current output to the voltage variable circuit is controlled based on the phase difference between the voltage and current of the transmitted power and the voltage and current of the received power.

In another aspect of the wireless power feeding device of the present invention, the impedance adjusting unit is detected by the first voltage detection circuit, the first current detection circuit, the second voltage detection circuit, and the second current detection circuit. The voltage and current of the transmitted power and the voltage and current of the received power are input, and it is determined whether or not the phase difference between the input voltage and current of the transmitted power and the voltage and current of the received power is within a predetermined range. When the phase difference is out of the predetermined range, the DC current output from the operating circuit to the variable inductance circuit is changed.

Another aspect of the wireless power feeding device of the present invention includes a position sensor for detecting the distance between the power transmission coupler and the power receiving coupler, and the impedance adjusting unit detects the distance detected by the position sensor. It is characterized in that it is input and the inductance of the adjusting coil of the variable inductance portion is changed based on the input distance.

Another aspect of the wireless power feeding device of the present invention includes a detection unit that detects a current flowing through an outer conductor of a cable connected to at least one of the power transmission coupler and the power reception coupler, and the impedance adjustment unit is the detection unit. It is characterized in that a current flowing through the outer conductor detected by the unit is input, and the inductance of the adjusting coil of the variable inductance unit is changed based on the input current.

Another aspect of the wireless power feeding device of the present invention further includes a variable capacitance section whose capacitance can be changed, and the impedance adjusting section includes the inductance of the adjusting coil and the variable capacitance section according to the state of the power transmission. It is characterized by changing the capacity.

An aspect of the impedance adjusting method of the wireless power feeding device of the present invention includes a power transmitting coupler having a power transmitting LC circuit and a power receiving coupler having a power receiving LC circuit, and the power transmitting LC circuit and the power receiving LC circuit are combined with each other. An impedance adjustment method used in a wireless power feeding device that wirelessly transmits power from a power transmitting coupler to the power receiving coupler by an electric field or a magnetic field, and is electrically connected to at least one of a power transmitting LC circuit and a power receiving LC circuit. The adjusting coil is provided, and the adjusting coil includes the adjusting coil, and has a variable inductance portion capable of changing the inductance of the adjusting coil. It is characterized by changing the inductance.

According to the present invention, the inductance of the power transmission LC circuit and / or the power reception LC circuit can be changed according to the state of power transmission. For example, in an electromagnetic field resonance type wireless power feeding device, when the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit deviate from each other, the inductance of the power transmission LC circuit and / or the power reception LC circuit is changed. Therefore, the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit can be substantially matched in a short time. As a result, when the wireless power feeding device of the present invention is used, power transmission can be performed with high power feeding efficiency.

It is a circuit diagram which schematically represented one configuration example of the wireless power feeding device by the electric field resonance method which concerns on one Embodiment of this invention. It is a circuit diagram which schematically represented the structure of the wireless power feeding apparatus 900 by the electric field resonance method of the prior art. It is a circuit diagram which schematically represented another configuration of the electric field resonance type wireless power feeding apparatus which concerns on one Embodiment of this invention. It is a figure which shows the BH curve of ferrite. It is a perspective view of the inductance variable circuit 60 of a basic structure. It is a perspective view of the inductance variable circuit 80 using an annular ferrite core. It is a figure for demonstrating the inductance variable circuit 70, (a) is the perspective view of the inductance variable circuit 70, (b) is the figure which represented the inductance variable circuit 70 by a circuit symbol, (c) is a figure. It is a front view of the ferrite core 73 of the inductance variable circuit 70. It is a graph which shows the inductance variable characteristic of the inductance variable circuit 70. It is a circuit diagram of inductance measurement. This is an inductance variable circuit 90 using a cylindrical ferrite core. It is a figure which shows the structure of the other variable inductance part. It is a circuit diagram for demonstrating the operation circuit 50. It is a block diagram for demonstrating feedback control. It is a flowchart of resonance frequency adjustment processing by feedback control. It is a circuit diagram which represented typically an example of the structure of the magnetic field resonance type wireless power feeding apparatus 300 which concerns on one Embodiment of this invention.

Hereinafter, the wireless power feeding device according to the preferred embodiment of the present invention will be described in detail with reference to the drawings. The description in the present embodiment shows an example of the wireless power feeding device according to the present invention, and is not limited thereto. The detailed configuration of the wireless power feeding device according to the present embodiment can be appropriately changed without departing from the spirit of the present invention. In addition, each component having the same function is indicated by the same reference numeral for the sake of illustration and simplification of description.

The wireless power supply device according to the present invention includes a power transmission coupler having a power transmission LC circuit and a power reception coupler having a power reception LC circuit, and the power transmission LC circuit and the power reception LC circuit are electrically coupled (including electric field resonance). ) Or magnetic power coupling (including magnetic resonance) to wirelessly transmit power from the power transmission coupler to the power reception coupler. First, the problems of the conventional wireless power feeding device will be described using the conventional wireless power feeding device 900 based on the electric field resonance method shown in FIG.

The wireless power supply device 900 is supplied with power received through a power supply unit 10 that supplies AC power having a predetermined resonance frequency, an electric field resonance type coupler 930 that wirelessly transmits power by an electric field resonance method, and an electric field resonance type coupler 930. The load 20 is provided. The electric field resonance type coupler 930 includes a power transmission coupler 931 and a power reception coupler 932, the power transmission coupler 931 is connected to the power supply unit 10, and the power reception coupler 932 is connected to the load 20.

The power transmission coupler 931 of the electric field resonance type coupler 930 includes two power transmission electrodes (first electrode 911 and second electrode 912) and two resonance coils (first resonance coil 913 and second resonance coil 914). The first electrode 911 and the second electrode 912 form a capacitor. One end of each of the first resonance coil 913 and the second resonance coil 914 is connected to the ends of the first electrode 911 and the second electrode 912, respectively. These two power transmission electrodes 911 and 912 and two resonance coils 913 and 914 form a resonance circuit (power transmission LC circuit). Further, the resonance frequency of the power transmission LC circuit is designed to substantially match the frequency of the AC power supplied.

Similarly, the power receiving coupler 932 also includes two power receiving electrodes 921 and 922 (third electrode and fourth electrode) and two resonance coils (third resonance coil and fourth resonance coil) 923 and 924. The three electrodes 921 and the fourth electrode 922 form a capacitor. Then, one end of each of the third resonance coil 923 and the fourth resonance coil 924 is connected to the ends of the third electrode 921 and the fourth electrode 922, respectively, to form a resonance circuit (power receiving LC circuit). The resonance frequency of the power receiving LC circuit is designed to substantially match the frequency of the received AC power. That is, the resonance frequency of the power receiving LC circuit is designed to substantially match the resonance frequency of the power transmission LC circuit described above.

The electric field resonance type coupler 930 causes electric field resonance between the power transmission LC circuit and the power reception LC circuit by arranging the power transmission electrodes 911 and 912 and the power reception electrodes 921 and 922 facing each other. That is, when the power transmission electrodes 911 and 912 and the power reception electrodes 921 and 922 are arranged to face each other with a predetermined interval D, respectively, and AC power of a predetermined frequency is supplied to the power transmission LC circuit, the power transmission electrodes 911 and 912 and the power transmission electrodes 911 and 912 are arranged. It is designed so that electric field resonance occurs between the power receiving electrodes 921 and 922, and power is supplied from the power transmission coupler 931 to the power receiving coupler 932.

However, for example, when the wireless power supply device 900 is used for wireless power supply of a vehicle such as an electric vehicle, the distance between the power transmission device having the power transmission coupler 931 and the vehicle having the power reception coupler 932 changes depending on the stop position of the vehicle. .. Therefore, the distance D (distance between couplers) between the power transmission coupler 931 and the power receiving coupler 932 may deviate from the distance between the couplers at the time of designing the use. In the electric field resonance type wireless power feeding device, the capacitance of the electric field resonance type coupler 930 also changes when the distance D between the couplers changes.

Here, the resonance frequency f of the LC circuit is represented by the equation (1). L is the inductance of the LC circuit and C is the capacitance of the LC circuit.
f = 1 / {2π (LC) ^1/2 } ・ ・ ・ ・ ・ (1)
Therefore, when the distance D between the couplers deviates from the distance between the couplers at the time of designing the use, the capacitance of the electric field resonance type coupler 930 changes, and the resonance frequency of the LC circuit also changes. As a result, the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit deviate from each other, and the conventional wireless power feeding device 900 has a problem that the power feeding efficiency becomes low.

The above-mentioned problem is not only a problem of the wireless power feeding device 900 by the electric field resonance method of the prior art, but also a similar problem in the wireless power feeding device of the magnetic field resonance method of the prior art. The conventional wireless power feeding device based on the magnetic field resonance method differs from the electric field resonance type wireless power feeding device 900 in that the magnetic field resonance type coupler is provided instead of the electric field resonance type coupler 930, but power is transmitted when the distance D between the couplers changes. The resonance frequency of the power receiving LC circuit and the resonance frequency of the power receiving LC circuit are the same. The reason for the deviation is that the capacitance of the electric field resonance type coupler changes in the electric field resonance type wireless power feeding device, but the inductance of the magnetic field resonance type coupler changes in the magnetic field resonance type wireless feeding device.

Therefore, in order to solve the above problems, the wireless power feeding device according to the present invention includes an adjusting coil electrically connected to at least one of a power transmitting LC circuit and a power receiving LC circuit, and the adjusting coil. It is equipped with a variable inductance unit that can change the inductance of the coil. Further, an impedance adjusting unit for changing the inductance of the adjusting coil of the variable inductance unit is provided according to power transmission. For example, in a wireless power feeding device using an electric field resonance method, the impedance adjustment unit adjusts the resonance frequency of the LC circuit connected to the adjustment coil by changing the inductance of the adjustment coil of the variable inductance unit to adjust the resonance frequency of the LC circuit for power transmission. The resonance frequency and the resonance frequency of the power receiving LC circuit can be substantially matched in a short time.

First, with reference to FIG. 1, a wireless power feeding device based on an electric field resonance method according to an embodiment of the present invention will be described. FIG. 1 is a circuit diagram schematically showing a configuration example of a wireless power feeding device based on an electric field resonance method according to an embodiment of the present invention.

The wireless power feeding device 100 of the present embodiment includes a power supply unit 10 that supplies AC power having a predetermined resonance frequency, a variable inductance unit 150, an electric field resonance type coupler 30 that wirelessly transmits power by an electric field resonance method, and an electric field resonance type coupler 30. It is provided with a load 20 to which the power received is supplied via the above, and an impedance adjusting unit 130. The electric field resonance type coupler 30 includes a power transmission coupler 31 and a power reception coupler 32, the power transmission coupler 31 is connected to a variable inductance unit 150 connected to the power supply unit 10, and the power reception coupler 32 is connected to the load 20. .. The variable inductance unit 150 includes an adjusting coil 140, and changes the inductance of the adjusting coil 140.

The power transmission coupler 31 of the electric field resonance type coupler 30 includes two power transmission electrodes (first electrode 111 and second electrode 112) and two resonance coils (first resonance coil 113 and second resonance coil 114). .. The power transmission electrodes 111 and 112 are, for example, rectangular plate electrodes, but the present invention is not limited thereto. By arranging the long side of the first electrode 111 on the side close to the second electrode 112 and the long side of the second electrode 112 facing the first electrode 111 substantially in parallel with a predetermined interval, the first electrode 111 and the first electrode 111 are arranged. The two electrodes 112 form a capacitor. One ends of the first resonance coil 113 and the second resonance coil 114 are connected to the ends of the first electrode 111 and the first electrode 112, respectively.

The variable inductance unit 150 is arranged so that the adjusting coil 140 is connected in series with the power transmission coupler 31. For example, in FIG. 13, the adjusting coil is the adjusting coil 71. Although the adjusting coil 140 is connected in series with the resonance coil 113 in FIGS. 1 and 13, the adjusting coil 140 may be connected in parallel with the resonance coil 113.

A resonance circuit (LC circuit for power transmission) is formed by two power transmission electrodes 111 and 112, two resonance coils 113 and 114, and an adjustment coil 140. The resonance frequency of the power transmission LC circuit is designed to substantially match the frequency of the AC power supplied by using the inductance of the adjusting coil 140 in the initial state when the variable inductance unit 150 is not operating.

The power receiving coupler 32 includes two power receiving electrodes 121 and 122 (third electrode and fourth electrode) and two resonance coils (third resonance coil and fourth resonance coil) 123 and 124, and the third electrode The third electrode 121 and the fourth electrode 122 form a capacitor by arranging the two opposite long sides of the 121 and the fourth electrode 122 substantially in parallel with a predetermined interval. Then, one ends of the third resonance coil 123 and the fourth resonance coil 124 are connected to the ends of the third electrode 121 and the fourth electrode 122, respectively, to form a resonance circuit (power receiving LC circuit). The resonance frequency of the power receiving LC circuit is designed to substantially match the frequency of the received AC power. That is, the resonance frequency of the power receiving LC circuit is designed to substantially match the resonance frequency of the power transmission LC circuit described above.

The electric field resonance type coupler 30 causes electric field resonance between the power transmission LC circuit and the power reception LC circuit by arranging the power transmission electrodes 111 and 112 and the power reception electrodes 121 and 122 so as to face each other. That is, when the power transmission electrodes 111 and 112 and the power reception electrodes 121 and 122 are arranged to face each other with a predetermined interval D, and AC power of a predetermined frequency is supplied to the power transmission LC circuit, the power transmission electrodes 111 and 112 and It is designed so that electric field resonance occurs between the power receiving electrodes 121 and 122, and power is supplied from the power transmission coupler 31 to the power receiving coupler 32.

The impedance adjustment unit 130 adjusts the resonance frequency of the transmission LC circuit provided with the variable inductance unit 150 by changing the inductance of the adjustment coil 140 of the variable inductance unit 150, and adjusts the resonance frequency of the transmission LC circuit and the power reception. Approximately match the resonance frequency of the LC circuit. For example, when the distance D between couplers changes from the distance between couplers in the design used, the capacitance of the electric field resonance type coupler 30 changes. As shown in the equation (1), the resonance frequency f of the LC circuit is determined by the inductance L and the capacitance C. Therefore, the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit deviate from each other. When the resonance frequency shift occurs in this way, the impedance adjustment unit 130 adjusts the resonance frequency of the power transmission LC circuit by changing the inductance of the adjustment coil 140 of the variable inductance unit 150, and the power transmission LC. The resonance frequency of the circuit and the resonance frequency of the power receiving LC circuit are substantially matched. As a result, the wireless power supply device 100 of the present embodiment can transmit power from the power transmission coupler 31 to the power reception coupler 32 with high power supply efficiency.

The wireless power supply device 100 of the present embodiment has a configuration in which a variable inductance unit 150 having an adjusting coil electrically connected to at least one of a power transmission LC circuit and a power reception LC circuit is provided in the power transmission LC circuit. It is a device, and has a configuration in which a variable inductance unit 150 is connected to a power transmission coupler 931 (FIG. 2) of the prior art to form a power transmission LC circuit, but the configuration is not limited to this. FIG. 3 is a circuit diagram schematically showing another configuration of the wireless power feeding device according to the electric field resonance method of the present embodiment. For example, as shown in FIG. 3A, a wireless power feeding device having a configuration in which a variable inductance unit 150 is arranged instead of the first resonance coil 113 connected to the power transmission electrode 111 to form a power transmission LC circuit may be used. Further, a wireless power feeding device having a configuration in which the variable inductance unit 150 is provided in the power receiving LC circuit may be used. For example, as shown in FIG. 3B, a wireless power feeding device having a configuration in which a variable inductance unit 150 is added to the power receiving LC circuit of the prior art to form a power receiving LC circuit may be used.

Further, a wireless power feeding device having a configuration in which the variable inductance unit 150 is provided in both the power transmission LC circuit and the power receiving LC circuit may be used. For example, as shown in FIG. 3C, a variable inductance unit 150 is added to the conventional power transmission LC circuit to form a power transmission LC circuit, and a variable inductance unit 150 is added to the conventional power transmission LC circuit. A wireless power supply device having a configuration for forming an LC circuit for receiving power may also be used. Further, in the examples shown in FIGS. 1 and 3, only one variable inductance unit 150 is provided in the power transmission LC circuit and the power reception LC circuit, but the present invention is not limited to this, and wireless power feeding is provided in a plurality of configurations. It may be a device. Further, the variable inductance unit 150 arranged in the power transmission LC circuit and the variable inductance unit 150 arranged in the power receiving LC circuit may be arranged in an unbalanced number and position.

(Variable inductance part)
Next, the variable inductance unit will be described. The variable inductance unit provided in the wireless power feeding device of the present embodiment may have any configuration as long as it is a circuit, mechanism, or the like that can change the inductance of the adjusting coil. Hereinafter, a configuration example of a preferable variable inductance unit in the wireless power feeding device of the present embodiment will be described.

The variable inductance unit preferably includes an inductance variable circuit in which the inductance of the adjusting coil changes based on the input DC current, and an operating circuit that outputs a DC current to the inductance variable circuit to operate the inductance variable circuit. ..

An example of an inductance variable circuit provided in the variable inductance unit will be described.
First, a variable inductance circuit using the magnetic characteristics of a magnetic material will be described. Hereinafter, in the present specification, ferrite will be described as an example of the magnetic material, but any magnetic material may be used as long as it is a magnetic material that is in a magnetically saturated state. For example, iron, nickel, etc. may be used.

There is a phenomenon that the magnetic flux is saturated when a current is continuously applied to a simple ferrite for a certain period of time or longer, and the apparent magnetic permeability μ (hereinafter, simply referred to as “magnetic permeability”) becomes very small.
FIG. 4 is a diagram showing a BH curve of ferrite. As can be seen from FIG. 4, when the ferrite is placed in a magnetic field and the magnetic field H is changed, the magnetic flux density B also changes. Then, in the state of magnetic saturation, the magnetic flux density B does not substantially change even if the magnetic field H is increased.
Here, the magnetic permeability μ is represented by the equation (2). B is the magnetic flux density and H is the magnetic field.
μ = B / H ・ ・ ・ ・ ・ (2)
Therefore, according to the equation (2), the magnetic permeability μ changes when the magnetic field H changes, and the magnetic permeability μ decreases as the magnetic field H is increased in the state of magnetic saturation.

The variable inductance circuit utilizing the magnetic characteristics of the magnetic material is a circuit that changes the inductance of the adjusting coil wound around the magnetic material core by changing the magnetic permeability μ of the magnetic material core. FIG. 5 is a perspective view of an inductance variable circuit 60 having a basic structure utilizing the magnetic characteristics of a magnetic material.

The variable inductance circuit 60 includes a ferrite core 63 having a structure in which a part of the annular core is cut off, an adjusting coil 61 formed so as to wind a main winding 66 around the ferrite core 63, and a control winding around the ferrite core 63. A control coil 62 formed so as to wind the 67 is provided.

The control coil 62 is a coil for changing the magnetic permeability μ of the ferrite core 63 by utilizing the magnetic saturation characteristic of the magnetic material. For example, when the auxiliary power supply to which a DC voltage is applied is connected to the ends 66a and 66b of the control winding 67 and the DC current flowing through the control coil 62 is changed by the impedance adjusting unit 130, the magnetic permeability μ of the ferrite core 63 is changed. Change.

The adjusting coil 61 is a coil whose inductance L changes according to a change in the magnetic permeability μ of the ferrite core 63, and electricizes the ends 66a and 66b of the main winding 66 to the power transmission LC circuit and / or the power receiving LC circuit. Connect and use. For example, in the wireless power feeding device 100 shown in FIG. 1, the end 66a of the main winding 66 is connected to the power supply unit 10, and the end 66b is connected to the power receiving coupler 32 (first resonance coil 113).
Here, the inductance L of the adjusting coil 61 is represented by the equation (3).
L = (μ ・ S ・ N ² ) / l ・ ・ ・ ・ ・ (3)
μ: Core magnetic permeability S: Core cross-sectional area N: Number of turns of main winding l: Magnetic path length From equation (3), when the magnetic permeability μ of the ferrite core 63 is changed, the inductance L of the adjusting coil 61 increases. Change.

Therefore, the variable inductance circuit 60 changes the magnetic permeability μ of the ferrite core 63 by changing the direct current flowing through the control coil 62, and further changes the magnetic permeability μ of the ferrite core 63 to change the inductance L of the adjusting coil 61. It is a circuit that can change. That is, it is a circuit capable of changing the inductance L of the adjusting coil 61 by changing the direct current flowing through the control coil 62.

As shown in FIG. 5, the ferrite core 63 has an open magnetic circuit structure in which a magnetic flux path (magnetic path) is formed in an open circuit, but a ferrite having a closed magnetic circuit structure in which a magnetic path is formed in a closed circuit. The core is preferable. This is because the ferrite core having a closed magnetic circuit structure can change the magnetic permeability μ to about 1 in a magnetically saturated state. For example, an annular ferrite core. FIG. 6 is a perspective view of an inductance variable circuit 80 using an annular ferrite core. The variable inductance circuit 80 includes an annular ferrite core 83, an adjustment coil 81 formed so as to wind the main winding around the ferrite core 83, and a control coil formed so as to wind the control winding around the ferrite core 83. It is equipped with 82. The inductance variable circuit 80 changes the magnetic permeability μ of the ferrite core 83 by changing the control current flowing through the control coil, and adjusts the inductance L of the adjusting coil. At this time, the magnetic permeability μ in the magnetically saturated state can be changed up to about 1. That is, since the variable width of the magnetic permeability μ of the ferrite core 83 can be widely changed from the order of 1000 to 10000 to about 1, the variable width of the inductance L of the adjusting coil 81 is also widened.

Next, an inductance variable circuit preferable to the inductance variable circuit 80 will be described. As shown in FIG. 6, the inductance variable circuit 80 has a configuration in which the adjusting coil 81 and the control coil 82 are transformer-coupled. Therefore, if it is simply arranged in the power transmission LC circuit and / or the power reception LC circuit, the magnetic field generated by the direct current flowing through the control coil 82 due to the transformer coupling may affect the adjustment coil 81. Therefore, the present inventor devised a method of winding the windings of the adjusting coil and the control coil and the shape of the ferrite core so that even if a direct current is passed through the control coil, the influence on the adjusting coil is small. The variable inductance circuit 70 was newly devised.

The inductance variable circuit 70 will be described. 7A and 7B are views for explaining the variable inductance circuit 70, FIG. 7A is a perspective view of the variable inductance circuit 70, and FIG. 7B is a diagram showing the variable inductance circuit 70 with a circuit symbol. c) is a front view of the ferrite core 73 of the variable inductance circuit 70.

The variable inductance circuit 70 winds a ferrite core 73 having a closed magnetic circuit structure, an adjusting coil 71 formed so as to wind a main winding 76 around a ferrite core 73 having a closed magnetic circuit structure, and a control winding 77 around the ferrite core 73. It includes a control coil 72 formed to rotate. The ferrite core 73 has a shape in which an E-shaped core made of the same material and a flat plate are integrated, the front surface and the back surface have a shape in which the letter "Sun" is laid horizontally, and the upper surface, the lower surface, and the left and right side surfaces are formed. It is a rectangular core. Here, when the ferrite core 73 is viewed from the front, the three vertical plate portions connecting the upper plate portion and the lower plate portion are arranged in the order of the first vertical plate portion 73a, the second vertical plate portion 73b, and the third vertical plate portion from one side surface side. 3 Vertical plate portion 73c.

The main winding 76 includes a first main winding 76a and a second main winding 76b, and the adjusting coil 71 includes a first main coil 71a and a second main coil 71b, and the first main coil 71a and the second. The main coils 71b are formed by connecting them in parallel. The first main coil 71a is a coil formed so as to wind the first main winding 76a around the first vertical plate portion 73a of the farite core 73, and the second main coil 71b is the second main coil 73a of the farite core 73. 3 This is a coil formed so as to wind the second main winding 76b around the vertical plate portion 73c. Further, the first main coil 71a and the second main coil 71b are formed so that the winding directions of the first main winding 76a and the second main winding 76b are opposite to each other and are connected in parallel. The control coil 72 is a coil formed so as to wind the control winding 77 around the second vertical plate portion 73b of the farite core 73.

In the variable inductance circuit 70, for example, when the ends 75a and 75b of the main winding 76 are connected to the auxiliary power supply and a DC voltage is applied to the adjusting coil 71 (first main coil 71a and second main coil 71b), the first A current flows through the main winding 71a in the direction of the solid line arrow 81a, and a current flows through the second main winding 71b in the direction of the solid line arrow 81b. At this time, the magnetic field generated by the current flowing through the first main winding 76a flows in the direction indicated by the dotted arrow 82a along the closed magnetic path in the ferrite core 73. Further, the magnetic field generated by the current flowing through the second main winding 76b flows in the direction indicated by the dotted arrow 82b along the closed magnetic path in the ferrite core 73. As a result, in the magnetic path in the second vertical plate portion 73b, the magnetic field generated by the current flowing in the first main winding 76a and the magnetic field generated by the current flowing in the second main winding 76b cancel each other out.

Therefore, in the variable inductance circuit 70 of the present embodiment, the control coil 72 is formed by winding the control winding 77 around a magnetic path (second vertical plate portion 73b of the farite core 73) in which magnetic fields cancel each other out. Therefore, the adjustment coil 71 and the control coil 72 are configured so as not to be transformer-coupled. Therefore, even if a direct current is passed through the control coil 72, the influence of the adjusting coil 71 (71a, 71b) can be reduced.

In the above embodiment, the first main winding 76a and the second main winding 76a and the second are such that the magnetic field generated by the current flowing through the first main winding 76a and the magnetic field generated by the current flowing through the second main winding 76b cancel each other out. The main windings 76b are formed so that the winding directions are opposite to each other and are connected in parallel. In addition, the magnetic fields excited by the first main winding 76a and the second main winding 76b are opposite to each other. It may be formed so as to face each other. For example, when the first main winding 76a and the second main winding 76b are connected in series, one end of the first main winding 76a (FIG. 15). By connecting the end connected to the middle 75a) and the other end of the second main winding 76b (the end connected to 75b in FIG. 15), it was created by the current flowing through the first main winding 76a. The magnetic field and the magnetic field generated by the current flowing through the second main winding 76b can be configured to cancel each other out in the same manner as in the above-described embodiment. In addition, when the first main winding 76a and the second main winding 76b are formed so that the winding directions are the same, one end of the first main winding 76a (connected to 75a in FIG. 15). The end to be wound) and the other end of the second main winding 76b (the end connected to 75b in FIG. 15) may be connected in parallel, or the first main winding 76a and the second main winding may be connected. One end of 76b may be connected in series.

FIG. 8 is a graph showing the variable inductance characteristic of the variable inductance circuit 70. In the graph, the horizontal axis is the control current I of the control coil 72, and the vertical axis is the inductance L of the adjustment coil 71. Further, FIG. 9 is a circuit diagram of inductance measurement. As shown in FIGS. 7 and 9, the inductance of the adjusting coil 71 of the variable inductance circuit 70 was measured with an LCR meter while changing the control current of the control coil 72 of the variable inductance circuit 70. As can be seen from the equation (3), the inductance L is a value that changes depending on the magnetic permeability μ, the cross-sectional area S of the core, the number of turns N of the windings of the adjusting coil, and the magnetic path length l. Therefore, the variable inductance characteristic differs depending on the difference in these parameters. In actual use, the inductance of the adjusting coil 71 is measured by measuring the inductance variable characteristics of the inductance variable circuit 70 to be used in advance and controlling the control current of the control coil 72 based on the measured inductance variable characteristics. L can be adjusted to a desired value.

As another structure of the inductance variable circuit utilizing the magnetic characteristics of the magnetic material, for example, a cylindrical ferrite core having a simple structure may be used. FIG. 10 is an inductance variable circuit 90 using a columnar ferrite core. The variable inductance circuit 90 includes a cylindrical ferrite core 93, an adjusting coil 91 formed so as to wind a main winding around the ferrite core 93, and a control formed so as to wind a control winding around the ferrite core 93. It includes a coil 92. The inductance variable circuit 90 can also adjust the inductance L of the adjusting coil 91 by changing the magnetic permeability μ of the ferrite core having an open magnetic path structure by changing the control current flowing through the control coil 92.

Next, an operating circuit that outputs a direct current to the variable inductance circuit to operate the variable inductance circuit will be described. The operating circuit may be any circuit as long as it can output a direct current, but an operating circuit that utilizes reflected power is preferable. The reflected power is power transmitted as a reflected wave reflected from the power transmitting coupler 31 to the power receiving coupler 32 without being transmitted. An operating circuit using reflected power will be described with reference to FIG. FIG. 12 is a circuit diagram for explaining the operating circuit 50. Here, the variable inductance circuit 70 will be described as the variable inductance circuit. As shown in FIG. 12, the operating circuit 50 includes a directional coupler 51 and a rectifying unit 52. The directional coupler 51 is arranged in a transmission line in which the reflected wave reflected from the power transmitting coupler 31 without being transmitted to the power receiving coupler 32 is transmitted as reflected power, and the reflected power is branched to the rectifying unit 52. Output. A circulator may be used as the directional coupler 51. The rectifying unit 52 is arranged between the directional coupler 51 and the inductance variable circuit 70 and is connected to each of them. The rectifying unit 52 rectifies and smoothes the AC reflected power input from the directional coupler 51 into DC power, and then outputs a DC current (control current) to the control coil 72 of the connected inductance variable circuit 70. .. As a result, the variable inductance circuit 70 can change the inductance of the adjusting coil 71 based on the direct current input to the control coil 72. A DC power supply may be provided so as to output DC power according to the reflected reflected power.

In addition to the operating circuit 50, the operating circuit may be a circuit that outputs a direct current from a constant current source to an inductance variable circuit as shown in FIG. Further, the AC power input from the power supply unit 10 may be rectified and smoothed into DC power, and then the DC current may be output to the variable inductance circuit.

The variable inductance unit described so far has been a variable inductance unit having a configuration including control coils (62, 72, 82, 92), but other configurations may be used. For example, as shown in FIG. 11, the adjustment coil 96 formed so as to wind the winding, the columnar ferrite core 97 inserted into the adjustment coil 96, and the relative positions of the adjustment coil 96 and the ferrite core 97. May be a variable inductance unit 95 provided with a position adjusting unit (not shown) that changes the inductance of the adjusting coil 96 by changing the above. The variable inductance unit 95 adjusts the inductance L of the adjusting coil 96 by changing the relative position of the ferrite core 97 and the adjusting coil 96 (for example, sliding the ferrite core 97 to change the relative position).

(Impedance adjustment unit)
Next, the impedance adjusting unit provided in the wireless power feeding device of the present embodiment will be described. The impedance adjusting unit changes the inductance of the adjusting coil of the variable inductance unit according to the state of power transmission. That is, the impedance adjusting unit 130 of the wireless power feeding device 100 of the present embodiment changes the inductance of the adjusting coil of the variable inductance unit (for example, the DC current output from the above-mentioned operating circuit 50 to the variable inductance circuit 70). (By changing the inductance of the adjusting coil by controlling), adjust the resonance frequency of the power transmission LC circuit and / or the power receiving LC circuit connected to the adjusting coil, and adjust the resonance frequency of the power transmission LC circuit and the power receiving LC. Approximately match the resonance frequency of the circuit. Hereinafter, preferable processing of the resonance frequency adjustment processing performed by the impedance adjustment unit will be described.

First, the resonance frequency adjustment process by feedback control will be described. FIG. 13 is a block diagram for explaining feedback control. Further, FIG. 14 is a flowchart of the resonance frequency adjustment process by feedback control. As shown in FIG. 13, in the wireless power supply device 100 of the present embodiment, the first voltage detection circuit 211 for detecting the voltage of the AC transmission power transmitted by the transmission coupler 31 and the first voltage detection circuit 211 for detecting the transmission power current. 1 A current detection circuit 212, a second voltage detection circuit 213 that detects the voltage of the AC received power received by the power receiving coupler 32, and a second current detection circuit 214 that detects the current of the received power are provided. The configuration should be such that the voltage and current of the transmitted power and the voltage and current of the received power can be detected. Then, the impedance adjusting unit 130 controls the control current (direct current) output to the inductance variable circuit 70 based on the phase difference between the detected voltage and current of the transmitted power and the voltage and current of the received power. For example, by performing the resonance frequency adjustment processing by the feedback control method shown in FIG. 14, the resonance frequency of the power transmitting LC circuit and the resonance frequency of the power receiving LC circuit are substantially matched.

In the resonance frequency adjustment process by feedback control, first, the value of the control current output from the DC current source 215 to the inductance variable circuit 70 is set to I0, which is an initial value, and is output from the DC current source 215 (S101). It should be noted that the current may not be output with I0 = 0. Here, the DC current source 215 may be, for example, reflected power to which a DC current is output by the operating circuit 50. Next, power is output from the AC power supply (S102). Next, the voltage and current of the transmitted power and the voltage and current of the received power detected by the first voltage detection circuit 211, the first current detection circuit 212, the second voltage detection circuit 213, and the second current detection circuit 214 are input. Then, the phase difference between the traveling wave output from the AC power source and the reflected wave flowing toward the power source is obtained from the voltage of the transmitted power and the voltage of the received power, and the current of the transmitted power and the current of the received power (S103). Next, it is determined whether or not the obtained phase difference is within a predetermined range (for example, ± 5 degrees or less) (S104). If the phase difference is within a predetermined range (Yes), the process ends. If the phase difference is not within a predetermined range (No), the value of the control current I output from the DC current source 215 to the inductance variable circuit 70 is increased by a predetermined value ΔI (for example, ΔI is 1A). (I = I + ΔI), output from the DC current source 215 (S105). After that, the process returns to step S103, and the processes of steps S103 to S105 are repeated in a predetermined cycle until the phase difference falls within a predetermined range. By this process, the inductance of the adjusting coil 71 is sequentially changed, and finally, the resonance frequency of the power transmission LC circuit and the resonance frequency of the power receiving LC circuit are substantially the same.

As the resonance frequency adjustment process, in addition to the above process by feedback control, there is also an adjustment process using a position sensor. For example, the wireless power feeding device 100 of the present embodiment is provided with a position sensor, and the position sensor detects the distance D between couplers. The impedance adjusting unit 130 inputs the inter-coupler distance D detected by the position sensor, and changes the inductance of the adjusting coil 140 of the variable inductance unit 150 based on the input inter-coupler distance D. As a result, the resonance frequency of either or both of the power transmission LC circuit and the power reception LC circuit provided with the variable inductance unit 150 is changed, and the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit are approximately abbreviated. Match.

There is also an adjustment process that utilizes the common mode current flowing through the outer conductor of the power transmission coupler or the cable connected to the power reception coupler. For example, the wireless power feeding device 100 of the present embodiment is provided with a detection unit for detecting the common mode current, and the detection unit detects the common mode current. The impedance adjusting unit 130 inputs the common mode current detected by the detecting unit, and changes the inductance of the adjusting coil 140 of the variable inductance unit 150 based on the input common mode current. As a result, the resonance frequency of either or both of the power transmission LC circuit and the power reception LC circuit provided with the variable inductance unit 150 is changed, and the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit are approximately abbreviated. Match.

As described above, the wireless power feeding device of the present embodiment is used in a state of impedance mismatch, for example, when the resonance frequency of the power transmitting LC circuit and the resonance frequency of the power receiving LC circuit deviate from each other. By changing the inductance of the circuit and / or the power receiving LC circuit, the resonance frequencies of the power transmitting LC circuit and the power receiving LC circuit can be easily substantially matched. As a result, when the wireless power feeding device of the present embodiment is used, power transmission can be performed with high power feeding efficiency. Further, since the specific band is narrow at high frequencies in the ISM frequency band, it is necessary to finely adjust the resonance frequency with high accuracy in adjusting the resonance frequency at high frequencies. Therefore, it is better that the variable width of the adjustment parameter is large. In the wireless power feeding device of the present embodiment, a magnetic permeability μ having a large variable width as compared with the dielectric constant ε is used. Therefore, adjusting the resonance frequency using the inductance can be finely adjusted with higher accuracy than adjusting the resonance frequency using the capacitance C.

The wireless power feeding device of the present embodiment described above has a configuration in which the inductance of the adjusting coil is changed to change the inductance of the power transmission LC circuit and / or the power receiving LC circuit. The impedance adjustment unit may change the inductance of the adjustment coil and the capacitance of the variable capacitance unit according to the state of power transmission.

Next, a magnetic field resonance type wireless power feeding device according to an embodiment of the present invention will be described. So far, the electric field resonance type wireless power feeding device has been described, but the magnetic field resonance type wireless power feeding device is the same as the electric field resonance type wireless power feeding device. FIG. 15 is a circuit diagram schematically showing a configuration example of a magnetic field resonance type wireless power feeding device 300 according to an embodiment of the present invention. The wireless power feeding device 300 of the present embodiment includes a power supply unit 10 that supplies AC power having a predetermined resonance frequency, a variable inductance unit 150, a magnetic field resonance type coupler 330 that wirelessly transmits power by a magnetic field resonance method, and a magnetic field resonance type coupler 330. It includes a load 20 to which power received is supplied via the above, and an impedance adjusting unit 130. The magnetic field resonance type coupler 330 includes a power transmission coupler 331 and a power reception coupler 332, the power transmission coupler 331 is connected to the power supply unit 10, and the power reception coupler 332 is connected to the load 20. The variable inductance unit 150 is the same as that described in the electric field resonance type wireless power feeding device, includes the adjusting coil 140, and can change the inductance of the adjusting coil 140.

The power transmission coupler 331 includes a first resonance coil 341, a first capacitor 342, and a variable inductance unit 150. Further, the resonance coil 341, the first capacitor 342 and the adjustment coil 140 are connected in series to form a resonance circuit (LC circuit for power transmission). The power receiving coupler 332 includes a second resonance coil 351 and a second capacitor 352, and the second resonance coil 351 and the second capacitor 352 are connected to form a resonance circuit (power receiving LC circuit). The resonance frequency of the power transmission LC circuit is designed to substantially match the frequency of the AC power supplied based on the inductance of the adjusting coil 140 in the initial state when the variable inductance unit 150 is not operating. ing. Further, the resonance frequency of the power receiving LC circuit is designed to substantially match the frequency of the received AC power. That is, the resonance frequency of the power receiving LC circuit is designed to substantially match the resonance frequency of the power transmission LC circuit described above. Then, in the magnetic field resonance type coupler 330, when the power transmission coupler 331 and the power reception coupler 332 are arranged to face each other at a predetermined interval and AC power of a predetermined frequency is supplied to the power transmission LC circuit, the power transmission LC circuit and the power reception LC circuit are supplied. It is designed so that a magnetic field resonance occurs between the power transmission coupler 331 and the power transmission coupler 332 to supply power to the power reception coupler 332.

The impedance adjustment unit 130 has the same function as that described in the electric field resonance type wireless power feeding device, and adjusts the resonance frequency of the power transmission LC circuit by changing the inductance of the adjustment coil 140 to resonate the power transmission LC circuit. The frequency and the resonance frequency of the power receiving LC circuit are substantially matched. For example, when the distance D between couplers changes from the distance D0 between couplers in the design used, the inductance of the magnetic field resonance type coupler 300 changes. As shown in the equation (1), since the resonance frequency f of the LC circuit is determined by the inductance L and the capacitance C, the resonance frequency of the LC circuit for transmission and the resonance frequency of the LC circuit for power reception deviate from each other. Therefore, the impedance adjustment unit 130 changes the inductance of the adjustment coil 140 of the variable inductance unit 150 so that the resonance frequency of the power transmission LC circuit and the resonance frequency of the power reception LC circuit substantially match, and the power transmission LC circuit Adjust the resonance frequency of. As a result, the wireless power supply device 300 of the present embodiment can transmit power from the power transmission coupler 331 to the power reception coupler 332 with high power supply efficiency.

The variable inductance unit 150 provided in the wireless power feeding device 300 of the present embodiment may be provided in either or both of the power transmission LC circuit and the power receiving LC circuit, similarly to the electric field resonance type wireless power feeding device. ..
From the above, it is possible to obtain the same effect as the wireless power feeding device by the magnetic field resonance method of the present embodiment with respect to the wireless power feeding device by the magnetic field resonance method of the present embodiment.

The impedance adjusting unit, the variable inductance unit (variable inductance circuit and the working circuit), the adjusting coil, and the like described in the present invention have not only power transmission by electric field resonance or magnetic field resonance, but also have an inductance depending on the power transmission state. It may be applied to other electric circuits that require modification. For example, in a wireless power feeding device using electric field coupling or magnetic field coupling that is not electric field resonance or magnetic field resonance, the present invention can be applied even when at least one of the inductances of the power transmitting side and the power receiving side is changed according to the power feeding state. ..

30 Electric field resonance type coupler 31 Transmission coupler 32 Power receiving coupler 50 Operating circuit 51 Directional coupler 52 Rectifier 60, 70, 80, 90 Inductance variable circuit 61, 71, 81, 91, 140 Adjustment coil 62, 72, 82 , 92 Control coil 63, 73, 83, 93 Ferrite core 100, 300 Wireless power supply device 130 Impedance adjustment unit 150 Variable inductance unit

Claims (13)

A power transmission coupler having a power transmission LC circuit and a power reception coupler having a power reception LC circuit are provided, and the power transmission LC circuit and the power reception LC circuit are connected to each other by an electric field or a magnetic field from the power transmission coupler to the power reception coupler. It is a wireless power supply device that wirelessly transmits power to
An adjustment coil that is electrically connected to at least one of the power transmission LC circuit and the power reception LC circuit.
A variable inductance unit that includes the adjusting coil and can change the inductance of the adjusting coil,
The variable inductance unit includes an impedance adjusting unit that changes the inductance of the adjusting coil of the variable inductance unit according to the state of power transmission.
An inductance variable circuit that changes the inductance of the adjustment coil based on the input DC current, and
An operating circuit that outputs a direct current to the variable inductance circuit to operate the variable inductance circuit,
With
The impedance adjusting unit controls a direct current output to the variable inductance circuit, and the operating circuit includes a directional coupler arranged in a transmission line through which alternating current reflected power is transmitted, the directional coupler, and the above. It is equipped with a rectifying unit arranged between variable inductance circuits.
The directional coupler branches the reflected power and outputs it to the rectifying unit.
The rectifying unit is a wireless power feeding device characterized in that the reflected power input from the directional coupler is rectified into a direct current and output to the variable inductance circuit. A first voltage detection circuit that detects the voltage of AC power transmitted by the power transmission coupler, and
The first current detection circuit that detects the current of the transmitted power and
A second voltage detection circuit that detects the voltage of the AC received power received by the power receiving coupler, and
A second current detection circuit for detecting the current of the received power is provided.
The impedance adjustment unit is
The voltage and current of the transmitted power and the voltage and current of the received power detected by the first voltage detection circuit, the first current detection circuit, the second voltage detection circuit and the second current detection circuit are input. The wireless power supply according to claim 1, wherein the DC current output to the variable inductance circuit is controlled based on the phase difference between the input voltage and current of the transmitted power and the voltage and current of the received power. apparatus. The impedance adjustment unit is
The voltage and current of the transmitted power and the voltage and current of the received power detected by the first voltage detection circuit, the first current detection circuit, the second voltage detection circuit and the second current detection circuit are input. It is determined whether or not the phase difference between the input voltage and current of the transmitted power and the voltage and current of the received power is within a predetermined range, and when the phase difference is out of the predetermined range, from the operating circuit. The wireless power feeding device according to claim 2 , wherein the DC current output to the variable inductance circuit is changed. A position sensor for detecting the distance between the power transmission coupler and the power reception coupler is provided.
Any of claims 1 to 3, wherein the impedance adjusting unit inputs the distance detected by the position sensor and changes the inductance of the adjusting coil of the variable inductance unit based on the input distance. The wireless power supply device according to item 1. A power transmission coupler having a power transmission LC circuit and a power reception coupler having a power reception LC circuit are provided, and the power transmission LC circuit and the power reception LC circuit are connected to each other by an electric field or a magnetic field from the power transmission coupler to the power reception coupler. It is a wireless power supply device that wirelessly transmits power to
An adjustment coil that is electrically connected to at least one of the power transmission LC circuit and the power reception LC circuit.
A variable inductance unit that includes the adjusting coil and can change the inductance of the adjusting coil,
The variable inductance unit includes an impedance adjusting unit that changes the inductance of the adjusting coil of the variable inductance unit according to the state of power transmission.
An inductance variable circuit that changes the inductance of the adjustment coil based on the input DC current, and
An operating circuit that outputs a direct current to the variable inductance circuit to operate the variable inductance circuit,
With
The impedance adjusting unit controls the direct current output to the variable inductance circuit, and controls the direct current.
A detection unit for detecting a current flowing through an outer conductor of a cable connected to at least one of the power transmission coupler and the power reception coupler is provided.
The impedance adjusting unit inputs a current flowing through the outer conductor detected by the detecting unit, and changes the inductance of the adjusting coil of the variable inductance unit based on the input current. .. The wireless power feeding device according to claim 5, wherein the operating circuit outputs a direct current from a constant current source to the variable inductance circuit. The wireless power feeding device according to claim 5 or 6, wherein the operating circuit rectifies AC power input from a power supply unit into DC power and outputs the AC power to the variable inductance circuit. The variable inductance circuit is
A magnetic core formed of a magnetically saturated magnetic material and
The adjusting coil formed so as to wind the main winding around the magnetic core,
A control coil formed so as to wind a control winding around the magnetic core,
With
The wireless power supply according to any one of claims 1 to 7, wherein when a direct current is input from the control winding, the magnetic permeability of the magnetic core is changed according to the input direct current. apparatus. The wireless power feeding device according to claim 8 , wherein the magnetic core has a magnetic path formed in a closed circuit. The magnetic core includes a first magnetic core portion, a second magnetic core portion, and a second magnetic core portion.
A third magnetic core portion arranged between the first magnetic core portion and the second magnetic core portion, and a third magnetic core portion.
A first magnetic core connecting portion and a second magnetic core connecting portion connecting the first magnetic core portion, the third magnetic core portion, and the second magnetic core portion from one and the other, respectively. Have,
The control coil is formed so as to wind the control winding around the third magnetic core portion.
The adjusting coil is formed so as to wind the first main winding and the second main winding around the first magnetic core portion and the second magnetic core portion, respectively, and the first main winding. It has a first main coil and a second main coil formed so that the magnetic fields excited in the wire and the second main winding are opposite to each other.
The first main coil, the second main coil, and the control coil are arranged between the first magnetic core connection portion and the second magnetic core connection portion, and the first magnetic core is provided. The wireless power feeding device according to claim 9, wherein the unit, the third magnetic core portion, and the second magnetic core portion are connected to each other. The wireless power feeding device according to claim 9, wherein the magnetic core is an annular core. The wireless power feeding device according to claim 8 , wherein the magnetic core is a columnar core. Further equipped with a variable capacitance section that can change the capacitance,
The wireless power feeding device according to any one of claims 1 to 12, wherein the impedance adjusting unit changes the inductance of the adjusting coil and the capacitance of the variable capacitance unit according to the state of power transmission. ..

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