WO2014030440A1 - Power supply device - Google Patents

Abstract

A power transmission unit is configured by arranging a plurality of resonators such that the resonators one-dimensionally or two-dimensionally form a periodic structure, and transmits power by radio by propagating power to adjacent resonators by a resonance action, and leaking an electromagnetic field to the surroundings. A power supply unit supplies power to one or more of the resonators of the power transmission unit. A power reception unit receives the transmitted power from the power transmission unit. Among the resonators which form the one-dimensional or two-dimensional periodic structure of the power transmission unit, resonators at ends are each loaded with a capacitive element.

Description

Power supply

The present invention relates to a power supply system, and more specifically, to a system that supplies power to a power receiving device without contact with a power transmission line.

A method of supplying power wirelessly to a separated power receiving apparatus is known. For example, Patent Document 1 discloses a configuration in which an electromagnetic wave propagates in an electromagnetic wave transmission sheet and an electromagnetic field leaking from the sheet is supplied to the power receiving device. This type of related technology is also disclosed in US Pat.
Patent Document 3 discloses a method of transmitting power from a primary coil on the power supply side to a secondary coil on the load side by magnetic coupling. This type of related technology is also disclosed in US Pat. This type of technology is often used for charging small household electronic devices such as shavers and electric toothbrushes.
Patent Document 5 discloses a power transmission method using a microwave beam. In this power transmission method, for example, solar power generation is performed on a satellite orbit, and energy obtained by power generation is transmitted to the ground with a microwave beam. Then, the microwave is reconverted into electric power by the ground power receiving device.
In recent years, a method of supplying power wirelessly to various electronic devices placed in a room has been sought, and an example thereof is disclosed in Non-Patent Document 1.
This concept is cited from the disclosure by Non-Patent Document 2.
The concept of “Proposal and Evaluation of Electromagnetic Resonance Multi-Hop Wireless Power Transmission System” studied by Professor Asami and Professor Kawahara of the University of Tokyo Graduate School The power is wirelessly supplied to a plurality of electronic devices arranged in the network.
The electronic device here includes, for example, a power transmission sheet, and there is a utilization form in which power is supplied to the small electronic device from the power transmission sheet.
Referring to FIG. 23, a plurality of coils 14 are arranged in a plane and embedded in a wall or floor 13 of room 10. And it utilizes that the coils which adjoin in the direction orthogonal to a central axis also resonate. That is, if power is supplied to one of the coils, the electric power hops to the adjacent coil.
Electric power is propagated to adjacent coils, and an electromagnetic field is leaked from the coil 14 into the room 10. Then, power can be supplied to a plurality of electronic devices 11 and a desk-top electronic device 12 arranged in a wide area of the room 10. Thereby, it can be expected that operations such as wiring of the power supply line, charging, battery replacement and the like are unnecessary.

JP 2008-66841 A JP 2007-281678 A JP-A-7-322534 US7825543 Specification JP 2008-259392 A

According to the above method, there is a possibility that power can be supplied wirelessly to the electronic device in the room.
However, the above method cannot guarantee that the electromagnetic field distribution for each coil is uniform, and it is expected that the power transmission efficiency greatly depends on the position of the power receiving device. Therefore, a technique for supplying power (transmitting power) wirelessly throughout the room is desired.
An object of the present invention is to provide a power supply system that can supply power efficiently without depending on the position of a power receiving device in wireless power feeding.

In the power supply system according to the aspect of the present invention, a plurality of resonators are arranged so as to form a one-dimensional or two-dimensional periodic structure, and power is propagated to an adjacent resonator by a resonance action, A power transmission unit that wirelessly transmits power by leaking an electromagnetic field, a power supply unit that supplies power to one or a plurality of the resonators of the power transmission unit, and a power receiving device that receives transmission power from the power transmission unit, Is provided. Among the plurality of resonators arranged so as to form a one-dimensional or two-dimensional periodic structure, a capacitive element is loaded on the resonator arranged at the end.

According to the present invention, it is possible to provide a power supply system that can efficiently supply power wirelessly without depending on the position of the power receiving apparatus.

FIG. 1 is a perspective view showing two examples of a power supply system to be realized in the present invention.
FIG. 2 is a diagram showing an example of a state in which electromagnetic propagation waves are generated in a periodic structure formed by a plurality of resonators arranged one-dimensionally.
FIG. 3 is a diagram showing a dispersion curve representing the relationship between the frequency (f) and the wave number (k) of electromagnetic propagation waves that can be generated in a periodic structure with a plurality of resonators.
FIG. 4 shows a single coil having an input port.
FIG. 5 is an equivalent circuit diagram of the coil of FIG.
FIG. 6 is a diagram showing a model in which two coils are arranged.
FIG. 7 is an equivalent circuit diagram of a circuit in which a plurality of coils are arranged at a constant pitch.
FIG. 8 is an equivalent circuit diagram for one unit (one cycle) of a periodic structure formed by a plurality of coils.
FIG. 9 is a diagram for explaining vibration in an example in which nine coils are arranged one-dimensionally.
FIG. 10 is a diagram showing a state where all of the plurality of coils arranged one-dimensionally vibrate in the same phase.
FIG. 11 is a diagram showing a state in which all of the plurality of coils arranged one-dimensionally vibrate in reverse phase.
FIG. 12 is a characteristic diagram showing an example of a dispersion curve.
FIG. 13 is a diagram showing the relationship between the frequency and the vibration state of each of the plurality of coils.
FIG. 14 is a diagram showing a termination portion of the equivalent circuit diagram of FIG.
FIG. 15 is a diagram showing a terminal portion of the equivalent circuit diagram of FIG.
FIG. 16 is a diagram showing (a) a capacitive element composed of a capacitance and (b) a capacitive element composed of an impedance inverter and an inductive element as an example of (c) a capacitive element loaded on a coil. is there.
FIG. 17 is a view showing a coil loaded with a capacitive element.
FIG. 18 is a diagram showing an example in which capacitive elements are loaded on coils at both ends of a one-dimensional coil array.
FIG. 19 is a diagram comparing current distributions when a capacitor is loaded on the coils at both ends of the coil arrangement and when a capacitor is not loaded.
FIG. 20 is a perspective view showing an embodiment of the present invention.
FIG. 21 is a diagram showing two examples of the coil arrangement in one embodiment of the present invention.
FIG. 22 is a diagram showing (a) a planar spiral coil and (b) a coil mounted on the back surface of the printed board as examples of the coil used in the embodiment of the present invention.
FIG. 23 is a diagram for explaining the concept of the electromagnetic resonance type multi-hop wireless power transmission method according to the related art.

(Basic concept)
First, FIG. 1A and FIG. 1B show two examples of a power supply system 100 to be realized by the present invention. The power supply system 100 includes a power transmission unit 110, a power reception device 120, and a power supply unit 130.
In FIG. 1A, the power receiving device 120 is not in electrical contact with the power transmission unit 110.
The power transmission unit 110 includes a plurality of resonators 111, and the plurality of resonators 111 are arranged two-dimensionally (planarly). As the resonator 111, for example, a conductor coil is typical. In FIGS. 1A and 1B, the resonator is a helical coil 112.
The power transmission unit 110 may be configured by, for example, a room wall or a floor itself. That is, for example, a plurality of resonators 111 (that is, the coils 112) are embedded in one surface of the floor, wall, or ceiling 115 of the room and used as the power transmission unit 110. The material of the floor, wall, or ceiling 115 may be anything as long as it does not impair the function as the power transmission unit.
The power feeding unit 130 supplies power to one or more resonators 111. An alternating current may flow from the power supply unit 130 to the resonator 111, or an oscillating magnetic field may be applied to the resonator 111.
In this configuration, when power is supplied from the power supply unit 130 to one or more resonators 111, the power hops between adjacent resonators, and the power propagates through the power transmission unit 110. And electromagnetic waves leak from the power transmission part 110 as shown to Fig.1 (a) and FIG.1 (b).
At this time, it is desired that the electromagnetic field distribution of the leaked electromagnetic wave is substantially uniform for each resonator without depending on the position of the power receiving device 120.
For example, in FIG. 1A, it is assumed that there are three power receiving apparatuses 120 to which power is supplied. In this case, it is desired to make the electromagnetic field intensity uniform at the three power receiving devices 120.
The theoretical background and specific configuration that enable such power supply will be described below.
(idea)
As a result of diligent research, the present inventors have conceived that a plurality of resonators are arranged to form a periodic structure, which is regarded as an electromagnetic field transmission line.
Furthermore, when this periodic structure was resonated in a specific frequency band, the idea was that this structure itself could be treated as a metamaterial.
Therefore, a method for analytically handling the electromagnetic field distribution generated in the periodic structure (transmission line) was pursued, and this could be achieved. In other words, a method has been developed to analytically determine what wave propagation modes occur in the periodic structure of the resonator.
As a result, for example, when the coils 112 that are the resonators are arranged as shown in FIG. 2, it is possible to determine what mode wave is generated by the electromagnetic field hopping. Hereinafter, this wave is referred to as “electromagnetic propagation wave”.
That is, the present inventors expressed the relationship between the frequency (f) and the wave number (k) of the electromagnetic propagation wave that can occur in the periodic structure of the coil as a dispersion curve as shown in FIG.
2d represents one cycle length of the periodic structure, and is, for example, a center-to-center distance between adjacent coils.
Therefore, “wave number (k) × one cycle length (d)” which is the horizontal axis of the graph of FIG. 3 means a phase change per cycle length.
In the dispersion curve of FIG. 3, it can be seen that the coil periodic structure can be treated as a metamaterial at a frequency f between f _max and f _min . The inventors have come up with a configuration in which an arbitrary electric field distribution is generated in the periodic structure (transmission line).
(Theory for obtaining the dispersion curve of electromagnetic wave propagation)
A method of obtaining a dispersion curve of electromagnetic propagation waves generated there by treating a resonator periodic structure in which resonators are periodically arranged as a metamaterial will be described. Here, a spring type coil is taken as an example of the resonator.
The resonance frequency fres, inductance L, capacitance C, and resistance R of a single coil are obtained, and further, a coupling constant M when two coils are arranged adjacent to each other is obtained.
First, the characteristics of a single coil can be calculated from the frequency dependence of impedance Z by inserting and connecting the input port 113 in the coil 112 (in the middle of coil wiring) as shown in FIG.
That is, the circuit of FIG. 4 is replaced with the equivalent circuit of FIG. 5 in which the capacitance component and the resistance component are extracted. Then, the frequency dependence of the real part Re (Z) and the imaginary part Im (Z) of the impedance Z is obtained by electromagnetic field analysis or actual measurement. Here, the impedance and the parameter of the equivalent circuit have the relationship of the following formula (1).

The resonance frequency f _res is obtained from the point at which Im (Z) is obtained.
An inductance L and a capacitance C are obtained by the following equation (2) using two points in the vicinity of the resonance frequency f _res .
Two points in the vicinity of the resonance frequency f _res are _defined as (f ₁ , Im (Z ₁ )) and (f ₂ , Im (Z ₂ )).

Next, the mutual inductance of the two coils 112 and 112 is obtained.
As shown in FIG. 6, the splitting of the resonance frequency is confirmed using a model in which two coils 112 and 112 are arranged.
In FIG. 6, power is supplied to one coil 112 from the input port 113, and the power is hopped to the other coil 112, and the power of the other coil 112 is obtained from the output port 114.
When the coupling between the two coils 112 and 112 is weak and the splitting cannot be confirmed, the splitting can be performed by changing the internal resistance of the input port 113 and the output port 114. Here, it is assumed that the resonance frequency f _res is split into a frequency f _a and a frequency f _b . Then, the coupling constant k can be calculated from the two split frequencies f _a and f _b by the following equation (3).

The mutual inductance M is obtained from the coupling constant k and the inductance L by the following relational expression (4).

Next, when a plurality of coils 112 are arranged horizontally at a constant pitch, an equivalent circuit thereof can be drawn as shown in FIG.
In FIG. 7, one coil 112 is depicted as being divided into two coil components 112h and 112h. Therefore, the inductance of one coil component 112h is L / 2. In this case, the resistance R is ignored.
Furthermore, one unit (one unit) of this periodic structure can be redrawn in the equivalent circuit of FIG. 8 by taking the mutual inductance M as a non-negative value.
Then, one unit (one unit) of the periodic structure can be expressed by the following formula (5) using a T matrix.

Let d be the periodic interval (distance between the centers of the coils) of this periodic structure.
Further, when the periodic structure is a metamaterial, the wave number in the traveling direction of the electromagnetic propagation wave traveling through the metamaterial is k _x .
Then, k _x × d represents the phase of the wave for each period, and the following equation (6) is established.

The dispersion relation is obtained by plotting the relation between the phase (k _x × d) and the frequency f (= ω / 2π) using the above formula (6).
Thereby, the frequency band (f _min <f < _max ) of the electromagnetic field wave generated in the metamaterial is obtained.
That is, the dispersion curve of FIG. 3 can be drawn in the frequency band (f _min <f <f _max ).
Up to this point, a dispersion curve was obtained when the coil periodic structure was a metamaterial. When any power is supplied to the coil periodic structure, the electromagnetic field is transmitted by hopping, and the coil periodic structure becomes a transmission line for electromagnetic propagation waves. Furthermore, if the transmission line loss is small, the electromagnetic field distribution on the transmission line is a so-called standing wave distribution.
(Example of configuration)
Up to this point, it was found that a coil periodic structure can be used as a transmission line, and a standing wave can be generated in the transmission line.
Furthermore, if a wave that satisfies the resonance condition of the coil periodic structure is generated, the number of antinodes of the standing wave (electromagnetic propagation wave) can be controlled.
The number of coils is n, the coil interval is d, and the phase between adjacent coils (the phase with respect to a certain frequency f in the dispersion curve) is X (= k _x × d) [rad].
When the resonance condition is satisfied, the following expression (7) is established.

Here, since the phase X is 0 ≦ X ≦ π, m satisfying the above equation (7) is n in m = 0, 1,... N−1.
As shown in FIG. 9, when the number of coils is nine (n = 9), there are phases X that satisfy nine resonance states of m = 0, 1,.
FIG. 9 shows a case where nine coils are arranged in a line at a constant pitch and power is supplied from the power supply unit 130 to the middle coil. For explanation, when the coil numbers 1 to 9 are assigned in order from the left in the figure, the middle fifth coil is a coil that receives power from the power supply unit 130.
The frequency of the power supplied from the power supply unit 130 (for example, the frequency of the alternating current) is controlled to be in a resonance state, and a standing wave of electromagnetic propagation waves is generated in the coil periodic structure.
In FIG. 9, the positions of the first, third, fifth, seventh and ninth coils are antinodes of standing waves, and the positions of the second, fourth, sixth and eighth coils are standing waves. It is a clause.
Note that m = 0 means that all coils are in phase as shown in FIG. In this case, the number of bellies is 1 (the number of nodes is 0).
For example, m = 8 means that all the coils are out of phase as shown in FIG. In this case, the number of bellies is 9 (the number of nodes is 8).
By utilizing such a phenomenon, the coil periodic structure is used as the power transmission unit 110, and the number of beams (locations at which the electromagnetic field strength is increased) can be controlled at positions close to the power transmission unit 110.
Here, based on the equivalent circuit diagram of FIG. 8, a dispersion curve derived from the equivalent circuit for each period is shown in FIG. In the calculation of FIG. 12, the self inductance of the coil is 2.4 μH, the self capacitance is 7.5 pF, and the mutual inductance is 0.19 μH.
Furthermore, FIG. 13 shows a result of circuit analysis in which nine coils corresponding to FIG. 9 are arranged at equal intervals based on the equivalent circuit diagram of FIG. The self-inductance, self-capacitance, and mutual inductance of the coil are 2.4 μH, 7.5 pF, and 0.19 μH, respectively, as in FIG. Further, each coil has an internal resistance of 1.8Ω, and the internal resistance of the power feeding port is 50Ω. The horizontal axis represents the coil number, and the vertical axis represents the current value for each coil.
As described so far, the combination of the phase and the frequency where the standing wave of the dispersion curve in FIG. 12 exists represents the current distribution having the desired number of antinodes at the corresponding frequency in FIG. I understand that.
Here, attention is paid to both ends of the current distribution diagram corresponding to each frequency in FIG. Theoretically, relational expression (7) that satisfies the resonance condition described above assumes that both ends of the coil are short-circuited, that is, the current is reflected without phase change. On the other hand, when FIG. 7 and FIG. 8 showing the equivalent circuit are viewed by the coil at the end as shown in FIG. 14 and FIG. 15, respectively, the impedance at the circuit end is not an ideal short end but an impedance value corresponding to the mutual inductance value. It can be seen that it is terminated with jωM (j is a unit imaginary number and ω is an angular frequency). It can be interpreted that this incomplete short end is a factor that the coil current values at both ends are relatively small with respect to the coil current value near the center as shown in FIG. Here, in order to approach the ideal short end, an element having an impedance value corresponding to −jωM may be loaded on the coils at both ends.
As an example of an element that realizes an impedance corresponding to −jωM, a capacitance having an appropriate capacitance can be considered. For example, as shown in FIG. 16A, the impedance of a capacitor having a capacitance C is represented by 1 / (jωC). Therefore, in order to represent the impedance corresponding to −jωM, −jωM = 1 / (jωC ), A capacitor satisfying C = 1 / (ω ² M) is suitable. In practice, a capacitor having a capacitance value very close to the capacitance value shown on the left (substantially equal value) may be selected from a range where it can be obtained or manufactured.
As another example of an element that realizes an impedance corresponding to −jωM, a circuit element in which an impedance inverter is connected to an inductor (inductive element) having an inductance value M as shown in FIG. Conceivable. Note that in the circuit diagram of FIG. 16B, the notation of the DC power supply necessary for the operation of the operational amplifier OP is omitted. The impedance inverter requires a DC power supply in addition to the passive circuit components. However, since the impedance value satisfies −jωM for each arbitrary frequency ω, an ideal short end at an arbitrary frequency on the dispersion curve diagram. There is an advantage that can be brought close to.
When the two-terminal element corresponding to −jωM is expressed as shown in FIG. 16C as described above, the two-terminal element (impedance element) 150 is inserted in series in the middle of the wiring of the coil 112 as shown in FIG. It is only necessary to connect and load them and place them at both ends of a normal coil arrangement as shown in FIG.
Here, a capacitor having a capacitance value of 79.4 pF is loaded on the coils at both ends of the coil array so that the impedance value is substantially the same as the impedance value indicated by −jωM at 41.3 MHz, which can be regarded as approximately f _{max in} the dispersion curve of FIG. FIG. 19 shows a calculation result when capacitors are loaded in series on the coils 112 at both ends of the coil arrangement in FIG. 12 and 13, the self-inductance, self-capacitance, and mutual inductance are 2.4 μH, 7.5 pF, and 0.19 μH, respectively, and each coil has a resistance of 1.8Ω as an internal resistance. Yes. FIG. 19 shows a result when a capacitor is not loaded on both terminal coils of the coil arrangement at 41.3 MHz as a comparative example.
From FIG. 19, it can be seen that the current distribution is flatter when the capacitor is loaded on both end coils of the coil arrangement than when the capacitor is not loaded. That is, it was shown that a uniform magnetic field distribution that is resistant to displacement of the power receiving coil (power receiving device) can be realized by loading capacitive elements on both terminal coils of the coil array.
(First embodiment of the present invention)
FIG. 20 is a conceptual diagram showing the first embodiment of the present invention. In FIG. 20, the power supply device 200 includes a power transmission unit 210, a power supply unit 220, and a power reception unit (power reception device) 280.
As described above, the power transmission unit 210 includes a coil as a resonance body, and a plurality of coils 211 are arranged so as to form a periodic structure. A capacitive element 160 is loaded on the resonators (coils) at both ends of the periodic structure. The power transmission unit 210 may be configured by a one-dimensional array of coils, but it is a matter of course that the coils may be arranged in a plane to form a two-dimensional periodic structure, which may be used as a power transmission unit.
For example, as shown in FIGS. 21A and 21B, it is assumed that there is an array structure of resonators (coils) 211 having a two-dimensional periodic structure. Here, a resonator surrounded by a dotted line is a capacitive element loaded resonator. As shown in FIG. 21A, capacitive elements may be loaded on a plurality of resonators at both ends in one direction (that is, a plurality of resonators in the rightmost and leftmost columns indicated by broken lines). Further, as shown in FIG. 21B, a capacitive element loaded type resonator may surround the outermost periphery as shown by a broken line with respect to the periodic structure of the two-dimensional resonator.
In the above-described embodiment, a helical coil is exemplified as the resonator, but a planar spiral coil shown in FIG. 22A may be used as the resonator, for example. The planar spiral coil 201 has an advantage that it can be mounted on a conventional printed circuit board. That is, one spiral coil 201 may be mounted on the front surface or the back surface of the printed board.
Alternatively, planar spiral coils may be mounted on both sides of the printed board. For example, the planar spiral coil 201 shown in FIG. 22A is mounted on the front side of the printed board. And the coil 202 of FIG.22 (b) is mounted in the back surface of a printed circuit board.
FIG. 22B is a perspective view of the coil 202 mounted on the back surface of the printed board from the front surface side.
At this time, a continuous spiral shape can be formed as double-sided mounting by electrically connecting the front side coil 201 and the back side coil 202 at the joint point 203.
Furthermore, by connecting the front-side coil 201 and the back-side coil 202 with a capacitive element, a capacitive element-loaded resonator for providing at both ends of the resonator array required in the present invention can be configured.
The capacitive element may be embedded in the front surface side coil 201 or may be embedded in the back surface side coil 202.
Although the case of surface mounting and double-side mounting has been described here, various spiral conductors can be mounted on a multilayer board by the spiral conductors of each layer and the conductors connecting the layers even in the multilayer board.
Further, in the multilayer substrate, various capacitive element loaded spiral conductors can be mounted on the multilayer substrate by the spiral conductors of the respective layers and the capacitive elements connecting the layers. In this case, the capacitive element may be embedded in the front side coil or in the back side coil.
22A and 22B illustrate a spiral coil having a rectangular shape and each side of the rectangle being a straight line shape, it goes without saying that it may be a curved spiral.
Moreover, the spiral coil may be mounted on the high dielectric substrate.
Alternatively, a spiral coil may be mounted on the magnetic material.
Thereby, magnetic flux density can be raised and size reduction of a resonance body (coil) can be achieved.
The coil may be a coil having a coil core made of a dielectric or magnetic material.
The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.
The space between the power transmission unit and the power reception device is generally air, but water, seawater, soil, or a wall may be provided between the power transmission unit and the power reception device. Moreover, there may be water, seawater, soil, and a wall so as to surround the power transmission unit and the power receiving device.
For example, the power transmission unit 110 may be an antenna for an RFID (Radio Frequency Identification) reader. The power receiving unit 120 may be an RFID tag.
For example, the power receiving device may be built in as a power supply source for a moving object such as a robot, such as a self-propelled floor cleaner, a look around in a room that can freely move on the floor, and a watching robot. . The power receiving device may also be incorporated into an autonomous submarine.
The resonance body (coil) of the power transmission unit may be sandwiched between two rigid substrates so that the power transmission unit does not bend.
Alternatively, the power transmission unit may be bent flexibly by sandwiching the resonator (coil) of the power transmission unit between two flexible sheets.
In this specification, the term “periodic structure” is used to express that the power transmission unit is composed of a periodic structure including a plurality of resonators.
Here, the periodic structure should not be construed to be limited to an array structure with a strictly constant pitch. It does not have to be strictly a constant cycle, and it is allowed that the arrangement pitch of the resonators deviates within a range in which the power transmission unit can be handled as a metamaterial in view of the entire purpose of the present invention.
Further, in the case of an actual product, the arrangement pitch of the resonators is designed in consideration of manufacturing restrictions, so that the arrangement period is allowed to deviate depending on the manufacturing conditions.
This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2012-184787 for which it applied on August 24, 2012, and takes in those the indications of all here.

DESCRIPTION OF SYMBOLS 100 Power supply system 110 Power transmission part 111 Resonator 112 Coil 112h Coil component 113 Input port 114 Output port 120 Power receiving apparatus 130 Power supply part 200 Power supply system 201 Coil (surface side coil)
202 coil (coil on the back side)
203 Junction

Claims (10)

1. A plurality of resonators are arranged in a one-dimensional or two-dimensional periodic structure, and power is propagated to the next resonator by resonance action, and electromagnetic fields are leaked to the surrounding area to transmit power wirelessly. A power transmission unit that performs
   A power supply unit that supplies power to one or more of the resonators of the power transmission unit;
   A power receiving device for receiving the transmitted power from the power transmission unit,
   Among the resonators arranged so as to form a one-dimensional or two-dimensional periodic structure, a capacitive element is loaded on a resonator disposed at an end or a resonator disposed on the outer periphery. A power supply device.
2. 2. The power supply device according to claim 1, wherein an absolute value of an impedance value of a capacitive element loaded on a resonator arranged at the end is substantially equal to an absolute value of an impedance value corresponding to a mutual inductance between the resonators. A power supply device characterized by being equal to each other.
3. 3. The power supply apparatus according to claim 1, wherein the capacitive element loaded on the resonator arranged at the end is a capacitor.
4. 3. The power supply apparatus according to claim 1, wherein the capacitive element loaded on the resonator arranged at the end includes an impedance inverter and an inductive element.
5. 5. The power supply apparatus according to claim 1, wherein the resonance body is a coil having a coil core made of a dielectric material or a magnetic material.
6. 6. The power supply apparatus according to claim 1, wherein the resonance body is a helical coil.
7. 6. The power supply apparatus according to claim 1, wherein the resonance body is a spiral coil.
8. The power supply apparatus according to any one of claims 1 to 7, wherein the power reception apparatus is an RFID tag.
9. 9. The power supply apparatus according to claim 1, wherein the power transmission unit is an RFID reader.
10. The power supply device according to any one of claims 1 to 7, wherein the power reception device is incorporated in a robot that can freely move around on a floor where the power feeding unit is provided.

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