WO2015050095A1 - Power transmission apparatus, power reception apparatus, and wireless power transmission system - Google Patents

Power transmission apparatus, power reception apparatus, and wireless power transmission system Download PDF

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Publication number
WO2015050095A1
WO2015050095A1 PCT/JP2014/075986 JP2014075986W WO2015050095A1 WO 2015050095 A1 WO2015050095 A1 WO 2015050095A1 JP 2014075986 W JP2014075986 W JP 2014075986W WO 2015050095 A1 WO2015050095 A1 WO 2015050095A1
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Prior art keywords
electrode
power
transformer
power transmission
voltage
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PCT/JP2014/075986
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French (fr)
Japanese (ja)
Inventor
市川敬一
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株式会社村田製作所
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Priority to JP2015540490A priority Critical patent/JP5935950B2/en
Publication of WO2015050095A1 publication Critical patent/WO2015050095A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/70—Circuit arrangements or systems for wireless supply or distribution of electric power involving the reduction of electric, magnetic or electromagnetic leakage fields

Definitions

  • the present invention relates to a power transmission device, a power reception device, and a wireless power transmission system that transmit power wirelessly by an electric field coupling method.
  • wireless power transmission can be performed simply by installing the electronic device in the charging device in order to eliminate the trouble of connecting a charging cable to the electronic device.
  • a method of transmitting electric power from a power transmission device (charging device) side to a power reception device (electronic device) side using electric field coupling is known (for example, see Patent Document 1).
  • each of the power transmitting device and the power receiving device includes an active electrode on the high potential side and a passive electrode on the low potential side, and the active electrodes and the passive electrodes are separated by a gap.
  • a strong electric field is formed between the electrodes by making them face each other, and the electrodes are electric field coupled. This electric field coupling enables wireless power transmission between devices.
  • an object of the present invention is to provide a power receiving device, a power transmitting device, and a wireless power transmission system in which a ratio of capacities generated in a high potential portion and a low potential portion can be easily set in order to suppress a change in reference potential. It is in.
  • the power receiving device includes a power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side
  • a power receiving apparatus comprising: a first transformer to which a voltage induced in a passive electrode is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein power is transmitted from the power transmitting apparatus by electric field coupling.
  • the first transformer has a primary coil and a secondary coil, a first end of the primary coil is connected to the power receiving side active electrode, and a second end is connected to a reference potential of the device itself.
  • the primary coil has a single-winding transformer, a primary coil, and a secondary coil.
  • the first end of the primary coil is connected to the passive passive electrode, and the second end is connected to the reference potential of the device.
  • the capacitance is C11
  • the inductance of the primary coil of the second winding transformer is L12
  • the second capacitance generated between the first end and the second end of the primary coil is C12
  • power transmission In the case of 1 / ⁇ C11 ⁇ L11 and 1 / ⁇ C12 ⁇ L12, C11 ⁇ C12, and when 1 / ⁇ C11> ⁇ L11 and 1 / ⁇ C12> ⁇ L12, L11 ⁇ L12. It is characterized by being.
  • the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first winding transformer and the second winding transformer so as to satisfy each condition. .
  • variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
  • first capacitance and the second capacitance are stray capacitances between windings of the primary coil of the first winding transformer and the second winding transformer.
  • the capacitance ratio generated between the active electrode (high potential part) and the passive electrode (low potential part) is set by combining the primary coil and the secondary coil according to the winding ratio of the winding transformer. it can.
  • the present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode
  • a first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein the first power is transmitted from the power transmission device by electric field coupling.
  • the transformer has a first winding transformer and a second winding transformer having a primary coil and a secondary coil, and the first winding transformer has a first end of the primary coil connected to the power receiving side active electrode.
  • the second end is connected to the first end of the primary coil of the second winding transformer, and the second end of the primary coil is the front end of the second winding transformer. It is the structure connected to the power receiving side passive electrode, and the electrostatic capacitance between the primary coil and the secondary coil of the first winding transformer is C13, the primary coil of the second winding transformer and the When the capacitance between the secondary coils is represented by C14, C13 ⁇ C14.
  • the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first winding transformer and the second winding transformer so as to satisfy each condition. .
  • variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
  • the present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode
  • a first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein the first power is transmitted from the power transmission device by electric field coupling.
  • the transformer includes a first piezoelectric transformer and a second piezoelectric transformer having a voltage input electrode, a voltage output electrode, and a reference potential electrode connected to a reference potential of the device itself, and the first piezoelectric transformer includes the voltage An input electrode is connected to the power receiving side active electrode, and the voltage output electrode is connected to the voltage output electrode of the second piezoelectric transformer.
  • the second piezoelectric transformer has a configuration in which the voltage input electrode is connected to the power-receiving-side passive electrode, and an electrostatic charge generated between the voltage input electrode of the first piezoelectric transformer and the reference potential electrode.
  • the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first winding transformer and the second winding transformer so as to satisfy each condition. .
  • variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
  • the power receiving device can be reduced in size and thickness.
  • the present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode
  • a first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein the first power is transmitted from the power transmission device by electric field coupling.
  • the transformer includes a first piezoelectric transformer and a second piezoelectric transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode, and a second voltage output electrode, wherein the first piezoelectric transformer One voltage input electrode is connected to the power receiving side active electrode, and the second voltage input electrode is connected to a reference potential of the device itself, and the second piezoelectric The lance has the second voltage input electrode connected to the power-receiving-side passive electrode, the first voltage input electrode connected to the second voltage input electrode of the first piezoelectric transformer, and a reference potential of the device itself.
  • the capacitance generated between the first voltage input electrode and the second voltage input electrode of the first piezoelectric transformer is C51, the first voltage input electrode, the second voltage input electrode, and the A capacitance generated between the first voltage output electrode and the second voltage output electrode is represented by C53, and a static electricity generated between the first voltage input electrode and the second voltage input electrode of the second piezoelectric transformer.
  • the capacitance generated between the first voltage input electrode and the second voltage input electrode and the first voltage output electrode and the second voltage output electrode is represented by C63, and C51 + C53 ⁇ C61 + C63. Ah It is characterized in.
  • the present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode
  • a first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage applied by the first transformer is applied, wherein the first transformer Includes a first piezoelectric transformer and a second piezoelectric transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode, and a second voltage output electrode, wherein the first piezoelectric transformer includes the first piezoelectric transformer
  • the voltage input electrode is connected to the power receiving side active electrode, and the second piezoelectric transformer is configured such that the second voltage input electrode is the power receiving side passive electrode.
  • the first voltage input electrode is connected to the second voltage input electrode of the first piezoelectric transformer, and the first voltage input electrode and the second voltage input electrode of the first piezoelectric transformer are connected.
  • a capacitance generated between the first voltage output electrode and the second voltage output electrode is represented by C53, and the first voltage input electrode, the second voltage input electrode, and the first voltage of the second piezoelectric transformer
  • the capacitance generated between the voltage output electrode and the second voltage output electrode is represented by C63, and C53 ⁇ C63.
  • the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first piezoelectric transformer and the second piezoelectric transformer so as to satisfy each condition.
  • variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
  • the power receiving device can be reduced in size and thickness.
  • the ratio between the capacitance generated between the active electrode and the reference potential and the capacitance generated between the passive electrode and the reference potential. can be set. Thereby, the fluctuation
  • FIG. 1 is a circuit diagram of a wireless power transmission system according to a first embodiment.
  • the figure which shows the equivalent circuit of the power receiving apparatus shown in FIG. Equivalent circuit diagram of a wireless power transmission system with some parts omitted
  • voltage fall part The figure which shows another example of the pressure
  • FIG. 10 is a diagram illustrating an example of a piezoelectric transformer according to a fifth embodiment. Equivalent circuit diagram of the wireless power transmission system shown in FIG. Diagram for explaining a method for measuring parasitic capacitance generated in a piezoelectric transformer Circuit diagram of wireless power transmission system according to Embodiment 6
  • FIG. 10 is a diagram illustrating an example of a piezoelectric transformer according to a sixth embodiment. The figure for explaining the measuring method of the capacitor which occurs in the piezoelectric transformer
  • FIG. 1 is a circuit diagram of a wireless power transmission system 1 according to the first embodiment.
  • the wireless power transmission system 1 includes a power transmission device 101 and a power reception device 201.
  • a power receiving apparatus 201 is placed on the power transmitting apparatus 101. In that state, the power transmission apparatus 101 transmits electric power to the power reception apparatus 201 using electric field coupling.
  • the power receiving apparatus 201 includes a load circuit RL including a secondary battery and a charging circuit, and charges the secondary battery with the power transmitted from the power transmitting apparatus 101.
  • the power transmission device 101 includes a power circuit 11.
  • the power supply circuit 11 converts a DC voltage (for example, DC 19 V) converted from an AC voltage (AC 100 V to 240 V) by an AC adapter connected to a commercial power source into an AC voltage using a DC-AC inverter circuit.
  • a step-up transformer 12 is connected to the power circuit 11.
  • the step-up transformer 12 is an insulated winding transformer having a primary coil and a secondary coil.
  • the primary coil is connected to the power supply circuit 11.
  • One end of the secondary coil is connected to the active electrode 13, and the other end is connected to the passive electrode 14.
  • the active electrode 13 and the passive electrode 14 are both flat, and the active electrode 13 has the same or smaller area than the passive electrode 14.
  • the active electrode 13 has the same or larger potential difference than the passive electrode 14 with respect to the reference potential of the power transmission device 101.
  • An alternating voltage boosted by the step-up transformer 12 is applied to the active electrode 13 and the passive electrode 14.
  • capacitors C1a and C1p are connected in series.
  • the connection point of the capacitors C1a and C1p is connected to the reference potential of the power transmission device 101.
  • the capacitance of the capacitor C1a (hereinafter referred to as C1a) is smaller than or equal to the capacitance of the capacitor C1p (hereinafter referred to as C1p), and the relationship of C1a ⁇ C1p is established.
  • the capacitors C1a and C1p suppress fluctuations in the reference potential and will be described in detail later.
  • the power receiving apparatus 201 includes an active electrode 23 and a passive electrode 24.
  • the active electrode 23 faces the active electrode 13 of the power transmission apparatus 101
  • the passive electrode 24 faces the passive electrode 14 of the power transmission apparatus 101.
  • the active electrode 23 and the passive electrode 24 are both flat, the active electrode 23 has the same area as the opposing active electrode 13, and the passive electrode 24 has the same area as the opposing passive electrode 14. . That is, the active electrode 23 has a smaller area or the same area as the passive electrode 24.
  • the active electrode 23 has a larger potential difference or the same potential as the reference potential of the power receiving device 201 than the passive electrode 24.
  • the capacitance generated (equivalently connected) between the active electrodes 13 and 23 is represented by a capacitor Ca
  • the capacitance generated (equivalently connected) between the passive electrodes 14 and 24 is represented by a capacitor Cp.
  • the capacitance of the capacitor Ca is represented by Caa
  • the capacitance of the capacitor Cp is represented by Cpp.
  • the active electrode 23 and the passive electrode 24 have the same area as the active electrode 13 and the passive electrode 14 facing each other.
  • the size of the electrodes is determined so that the facing area between the active electrodes 13 and 23 is smaller than or equal to the facing area between the passive electrodes 14 and 24, and the relationship of Caa ⁇ Cpp may be established.
  • a load circuit RL is connected to the active electrode 23 and the passive electrode 24 via a step-down unit 25, a rectifying diode bridge DB, a smoothing inductor L1, and a capacitor Co.
  • a voltage is applied to the active electrode 13 and the passive electrode 14 of the power transmission device 101, the active electrodes 13 and 23 and the passive electrodes 14 and 24 are electrically coupled.
  • a voltage is induced in the active electrode 23 and the passive electrode 24.
  • the step-down unit 25 steps down the induced voltage.
  • the step-down unit 25 corresponds to a “first transformer” according to the present invention.
  • the step-down unit 25 has two winding transformers T21 and T22.
  • the winding transformer T21 corresponds to the first winding transformer according to the present invention
  • the winding transformer T22 corresponds to the second winding transformer according to the present invention.
  • Winding transformers T21 and T22 have a primary coil and a secondary coil.
  • a capacitor C11 indicated by a broken line in the figure is a stray capacitance between windings of the primary coil of the winding transformer T21.
  • the capacitor C12 is a stray capacitance between windings of the primary coil of the winding transformer T22.
  • the primary coils of the winding transformers T21 and T22 and the secondary coils are connected in series.
  • a connection point of the primary coils connected in series is connected to the reference potential of the power receiving device 201. More specifically, one end of the primary coil of the winding transformer T21 is connected to the active electrode 23, and the other end is connected to the reference potential of the power transmission apparatus 101.
  • One end of the primary coil of the winding transformer T22 is connected to the passive electrode 24, and the other end is connected to the reference potential of the power transmission apparatus 101.
  • the secondary coils of the winding transformers T21 and T22 are connected in series.
  • condition (1) When 1 / ⁇ C11 ⁇ L11 and 1 / ⁇ C12 ⁇ L12, the influence of the capacitances C11 and C12 is dominant in the fluctuation of the reference potential of the power receiving apparatus 201.
  • the winding transformers T21 and T22 are selected so as to satisfy at least the condition of C11 ⁇ C12 (hereinafter referred to as condition (1)).
  • condition (2) the condition of L11 ⁇ L12
  • FIG. 2 is a diagram showing an equivalent circuit of the power receiving device 201 shown in FIG.
  • the step-down unit 25 can be equivalently represented by the circuit shown in FIG.
  • the primary coil of the winding transformers T21 and T22 connected in series is represented by one primary coil n1
  • the secondary coil of the winding transformers T21 and T22 connected in series is one secondary coil. This is represented by n2.
  • the capacitors C11 and C12 can be represented by a configuration in which the capacitors C11 and C12 are connected in series between the active electrode 23 and the passive electrode 24, as shown in FIG.
  • the connection point between the capacitors C11 and C12 is connected to the reference potential of the power receiving device 201.
  • FIG. 3 is an equivalent circuit diagram of the wireless power transmission system 1 with a part omitted.
  • FIG. 3 mainly shows a circuit composed of capacitors C1a, C1p, C11, C12 and capacitors Ca, Cp, and other circuits, for example, the diode bridge DB of the power receiving device 201, are grouped as a load circuit RL.
  • 3 is a reference potential point of the power transmitting apparatus 101
  • RG is a reference potential point of the power receiving apparatus 201.
  • the reference potential of the power receiving apparatus 201 can be stabilized by suppressing the potential difference between the power transmitting apparatus side reference potential point TG and the power receiving apparatus side reference potential point RG.
  • the impedances of the capacitors C1a and C1p are represented by Z1 and Z2.
  • the impedance of the capacitor C11 and the inductor L11 connected in parallel is represented by Z3, and the impedance of the capacitor C12 and the inductor L12 connected in parallel is represented by Z4.
  • the resistance component is ignored.
  • the impedances Z1, Z2, Z3, and Z4 are expressed by the following equations (1) to (4) (in the following, the symbol “//” represents parallel connection).
  • Z1 1 / j ⁇ C1a (1)
  • Z2 1 / j ⁇ C1p (2)
  • Z3 (j ⁇ L11) // (1 / j ⁇ C11) (3)
  • Z4 (j ⁇ L12) // (1 / j ⁇ C12) (4)
  • the reference of the power receiving device 201 As described above, by making the capacitance ratio of the capacitances C1a and C1p, the capacitance ratio of the capacitances Caa and Cpp, the capacitance ratio of the capacitances C11 and C12, or the inductance ratio of the inductances L2p and L2a, the reference of the power receiving device 201 The potential can be prevented from fluctuating.
  • the winding transformers T21 and T22 are configured so as to be the same as (or close to) the capacitance ratio of the capacitors Ca and Cp when the power receiving apparatus 201 is manufactured. You just have to decide on a combination.
  • an existing winding transformer may be selected as appropriate, and it is necessary to newly design the winding transformer to suppress the variation of the reference potential. Absent. Further, it is not necessary to provide the elements of the capacitors C11 and C12, and the power receiving device 201 can be saved in space.
  • the step-down unit 25 according to the present embodiment is not limited to the above-described configuration.
  • 4A and 4B are diagrams illustrating another example of the step-down unit 25.
  • FIG. 4A and 4B are diagrams illustrating another example of the step-down unit 25.
  • the secondary coils of the winding transformers T21 and T22 of the step-down unit 25 are connected in series, but the secondary coils may be connected in parallel as shown in FIG. 4A.
  • the step-down unit 25 according to the present embodiment is an insulated winding transformer that can handle a high voltage, but the step-down unit 25 has non-insulated winding transformers T21 and T22 as shown in FIG. 4B. A winding transformer may be used.
  • the primary coils of the winding transformers T21 and T22 are connected in series, and the connection point is connected to the reference potential of the power receiving apparatus 201, but is connected to the reference potential. You don't have to.
  • FIG. 5 is a diagram illustrating an example in which the connection point of the primary coil of the winding transformers T21 and T22 included in the step-down unit 25 is not connected to the ground.
  • the primary sides of the winding transformers T21 and T22 are insulated from the reference potential of the power receiving device 201.
  • the inductances L11 and L12 and the capacitances C11 and C12 do not contribute to fluctuations in the reference potential of the power receiving apparatus 201. Therefore, in this example, in order to suppress the fluctuation of the reference potential of the power receiving apparatus 201, the primary-secondary capacitance C13 of the winding transformer T21 and the primary-order of the winding transformer T22 are illustrated.
  • the winding transformers T21 and T22 need to be combined so that the relationship between the secondary capacitance C14 satisfies C13 ⁇ C14.
  • the voltage generated in the secondary coil is sufficiently low. Since the secondary coil is connected to the reference potential, it can be equivalently viewed as a circuit having the entire secondary coil as the reference potential.
  • the ratio between the capacitance C13 and the capacitance C14 is adjusted to (close to) the ratio between the capacitances Caa and Cpp. That is, the condition of C13 ⁇ C14 can be derived from the relationship of Caa ⁇ Cpp.
  • FIG. 6 is a diagram for explaining the capacitances C13 and C14.
  • a line capacitance C01 is generated between the primary coil and the secondary coil of the winding transformer T21.
  • the capacitance C13 is an equivalent representation of the inter-line capacitance C01.
  • a line capacitance C02 is generated between the primary coil and the secondary coil of the winding transformer T22.
  • the capacitance C14 is an equivalent representation of the inter-line capacitance C02.
  • the power transmission device 101 includes the step-up transformer 12 and the power reception device 201 includes the step-down unit 25.
  • the transformers included in the devices 101 and 201 are not limited to step-up and step-down.
  • the power transmission device 101 and the power reception device 201 may include an insulating transformer that does not transform
  • the power transmission device 101 may include a step-down transformer
  • the power reception device 201 may include a step-up transformer.
  • the winding transformer of the step-up transformer is appropriately combined using the capacitors C11 and C12 that are capacitor components included in the step-up transformer, as in the present embodiment, and You may make it suppress the fluctuation
  • Emodiment 2 In the present embodiment, the configuration of the step-up transformer included in the power transmission device of the wireless power transmission system is different from that in the first embodiment.
  • the power receiving apparatus is the same as that in the first embodiment.
  • FIG. 7 is a circuit diagram of the power transmission apparatus 102 according to the second embodiment.
  • the power transmission device 102 includes a power supply circuit 11, a booster 15, an active electrode 13, and a passive electrode 14.
  • the booster 15 has two winding transformers T11 and T12.
  • the booster 15 corresponds to a second transformer according to the present invention.
  • the winding transformer T11 corresponds to a third winding transformer according to the present invention, and the winding transformer T12 corresponds to a fourth winding transformer according to the present invention.
  • Winding transformers T11 and T12 have a primary coil and a secondary coil.
  • a capacitor C21 indicated by a broken line in FIG. 7 is a stray capacitance between windings of the secondary coil of the winding transformer T11.
  • the capacitor C22 is a stray capacitance between windings of the secondary coil of the winding transformer T12.
  • the primary coils and secondary coils of the winding transformers T11 and T12 are connected in series.
  • the connection point of the secondary coils connected in series is connected to the reference potential of the power transmission device 102. More specifically, one end of the secondary coil of the winding transformer T ⁇ b> 11 is connected to the active electrode 13, and the other end is connected to the reference potential of the power transmission device 102.
  • One end of the secondary coil of the winding transformer T ⁇ b> 12 is connected to the passive electrode 14, and the other end is connected to the reference potential of the power transmission device 102.
  • the primary coils of the winding transformers T11 and T12 are connected in series.
  • the inductance of the secondary coil of the winding transformer T11 is represented by L21, and the capacitance of the capacitor C21 of the primary coil is represented by C21. Further, the inductance of the secondary coil of the winding transformer T12 is represented by L22, and the capacitance of the capacitor C22 of the primary coil is represented by C22.
  • the operating angular frequency during power transmission of the wireless power transmission system 1 is represented by ⁇ .
  • the winding transformers T11 and T12 are selected so as to satisfy at least the condition of C21 ⁇ C22 (hereinafter referred to as condition (3)). Thereby, the fluctuation
  • variation of the reference electric potential of a receiving device can be suppressed. Further, if C21 / C22 Caa / Cpp, fluctuations in the reference potential of the power receiving apparatus can be further stabilized.
  • the influence of the inductances L21 and L22 is dominant in the fluctuation of the reference potential of the power receiving apparatus.
  • the winding transformers T11 and T12 are selected so as to satisfy at least the condition of L21 ⁇ L22 (hereinafter referred to as condition (4)). Thereby, the fluctuation
  • variation of the reference electric potential of a receiving device can be suppressed. Further, if L22 / L21 Caa / Cpp, the fluctuation of the reference potential of the power receiving apparatus can be more stabilized.
  • the winding transformer T11 of the step-up unit and the winding transformer T21 of the step-down unit are the same winding transformer.
  • the winding transformer T12 of the step-up unit and the winding transformer T22 of the step-down unit can use the same winding transformer.
  • the power transmission device 101 and the power receiving device 201 can have substantially the same capacity ratio, and the reference potential of the power receiving device 201 can be further stabilized.
  • connection point of the secondary coils of the winding transformers T11 and T12 included in the boosting unit 15 may not be connected to the ground.
  • the secondary sides of the winding transformers T11 and T12 are insulated from the reference potential of the power transmission device 102.
  • inductance L21, L22 and capacitance C21, C22 do not contribute to the fluctuation
  • FIG. Therefore, in this example, in order to suppress the fluctuation of the reference potential of the power transmitting apparatus 102, the primary-secondary capacitance C23 of the winding transformer T11 and the primary-secondary of the winding transformer T12. It is necessary to combine the winding transformers T11 and T12 so that the relationship with the electrostatic capacity C24 satisfies C23 ⁇ C24.
  • FIG. 8 is a circuit diagram of a power receiving device of the wireless power transmission system according to the third embodiment.
  • the power receiving device 202 according to the present embodiment is different from the first embodiment in the configuration of the step-down unit 26.
  • the power transmission device of the wireless power transmission system is the same as that of the first embodiment.
  • the step-down unit 26 includes Rosen-type piezoelectric transformers 261 and 262.
  • the piezoelectric transformer 261 corresponds to the first piezoelectric transformer according to the present invention
  • the piezoelectric transformer 262 corresponds to the second piezoelectric transformer according to the present invention.
  • the piezoelectric transformer 261 vibrates in the ⁇ resonance mode
  • the piezoelectric transformer 262 vibrates in the ( ⁇ / 2) resonance mode.
  • the piezoelectric transformers 261 and 262 have first electrodes E11 and E21, second electrodes E12 and E22, and third electrodes E13 and E23.
  • the first electrode E11 of the piezoelectric transformer 261 is connected to the active electrode 23.
  • the first electrode E ⁇ b> 21 of the piezoelectric transformer 262 is connected to the passive electrode 24.
  • the second electrodes E12 and E22 of the piezoelectric transformers 261 and 262 are connected to the reference potential of the power receiving device 202.
  • the third electrodes E13 and E23 of the piezoelectric transformers 261 and 262 are connected to a resonance inductor L2, a rectification diode bridge DB, a smoothing inductor L1, and a capacitor Co.
  • the piezoelectric transformers 261 and 262 when a voltage is applied to the first electrodes E11 and E21, the piezoelectric transformers 261 and 262 generate stress at a period corresponding to the drive signal due to the inverse piezoelectric effect, and the voltage is lowered due to the mechanical distortion. The voltage is output from the third electrodes E13 and E23. In the piezoelectric transformers 261 and 262, the first electrodes E11 and E21 and the third electrodes E13 and E23 maintain insulation. For this reason, in the step-down unit of the power receiving apparatus 202, the influence of noise due to the high-voltage unit (the coupling of the active electrodes 13 and 23) to the load circuit RL side can be suppressed by electrically insulating the input and output.
  • a capacitor C15 indicated by a broken line in FIG. 8 is a capacitance component generated between the first electrode E11 and the second electrode E12 of the piezoelectric transformer 261, and the capacitor C16 is a first electrode E21 and a second electrode E22 of the piezoelectric transformer 262. Is a capacitance component generated between The third electrodes E13 and E23 are connected to the reference potential of the power receiving device 202.
  • the capacitor C15 is a capacitance generated between the active electrode 23 and the reference potential
  • the capacitor C16 is a capacitance generated between the passive electrode 24 and the reference potential.
  • the piezoelectric transformer 261 vibrates in the ⁇ resonance mode and the piezoelectric transformer 262 vibrates in the ( ⁇ / 2) resonance mode
  • the distance between the first electrode E11 and the second electrode E12 is the first electrode E21 and the first electrode E21. It is longer than the distance to the two electrodes E22. That is, the capacitance of the capacitor C15 (hereinafter represented by C15) is smaller than the capacitance of the capacitor C16 (hereinafter represented by C16). For this reason, the relationship of C15 ⁇ C16 is established.
  • the relationship of C15 16 is established.
  • the capacitors C15 and C16 can be regarded as a circuit configuration in which the connection points of the capacitors C15 and C16 are connected to the reference potential in series between the active electrode 23 and the passive electrode 24 as in the first embodiment. .
  • the influence of the capacitors C15 and C16 becomes dominant, fluctuations in the reference potential of the power receiving apparatus 202 can be suppressed by combining the piezoelectric transformers 261 and 262 so that C15 ⁇ C16 holds.
  • C15 / C16 Caa / Cpp
  • fluctuations in the reference potential of the power receiving apparatus 202 can be further stabilized.
  • the voltage step-down unit 26 is configured by the piezoelectric transformers 261 and 262 so that the power receiving device 202 is reduced in size and thickness. Can be realized.
  • the configuration of the step-up transformer included in the power transmission device of the wireless power transmission system is different from that in the third embodiment.
  • the power receiving device is the same as the power receiving device according to the first or third embodiment.
  • FIG. 9 is a circuit diagram of the power transmission device 103 according to the fourth embodiment.
  • the power transmission device 103 includes a power supply circuit 11, a booster 16, an active electrode 13, and a passive electrode 14.
  • the step-up unit 16 has two Rosen-type piezoelectric transformers 161 and 162.
  • the piezoelectric transformer 161 corresponds to the third piezoelectric transformer according to the present invention
  • the piezoelectric transformer 162 corresponds to the fourth piezoelectric transformer according to the present invention.
  • the piezoelectric transformer 161 vibrates in the ⁇ resonance mode
  • the piezoelectric transformer 162 vibrates in the ( ⁇ / 2) resonance mode.
  • the piezoelectric transformers 161 and 162 have first electrodes E31 and E41, second electrodes E32 and E42, and third electrodes E33 and E43.
  • the first electrode E31 of the piezoelectric transformer 161 is connected to the active electrode 13.
  • the first electrode E41 of the piezoelectric transformer 162 is connected to the passive electrode 14.
  • the second electrodes E32 and E42 of the piezoelectric transformers 161 and 162 are connected to the reference potential of the power transmission device 103.
  • the third electrodes E33 and E43 of the piezoelectric transformers 161 and 162 are connected to the power supply circuit 11.
  • the piezoelectric transformers 161 and 162 when the AC voltage is applied to the piezoelectric transformers 161 and 162 from the power supply circuit 11 to the second electrodes E32 and E42 and the third electrodes E33 and E43, the piezoelectric transformers 161 and 162 have an inverse piezoelectric effect. Stress is generated at a period corresponding to the drive signal, and a voltage boosted by the mechanical strain is output from the first electrodes E31 and E41. The voltage boosted by the piezoelectric transformers 161 and 162 is applied to the active electrode 13 and the passive electrode 14.
  • a capacitor C25 indicated by a broken line in FIG. 9 is a capacitance component generated between the first electrode E31 and the second electrode E32 of the piezoelectric transformer 161, and the capacitor C26 is a first electrode E41 and a second electrode E42 of the piezoelectric transformer 162. Is a capacitance component generated between The third electrodes E33 and E43 are connected to the reference potential of the power transmission device 103.
  • the capacitor C25 is a capacitance generated between the active electrode 13 and the reference potential
  • the capacitor C26 is a capacitance generated between the passive electrode 14 and the reference potential.
  • the distance between the first electrode E31 and the second electrode E32 of the piezoelectric transformer 161 is the piezoelectric transformer. 162 is longer than the distance between the first electrode E41 and the second electrode E42. That is, the capacitance of the capacitor C25 (hereinafter represented by C25) is smaller than the capacitance of the capacitor C26 (hereinafter represented by C26). For this reason, the relationship of C25 ⁇ C26 is established.
  • C25 C26
  • the capacitors C25 and C26 are connected in series between the active electrode 13 and the passive electrode 14 as in the second embodiment, and can be regarded as a circuit configuration in which the connection point of the capacitors C25 and C26 is connected to the reference potential. .
  • the power transmission device 103 can be reduced in size and thickness.
  • the piezoelectric transformer 261 of the step-down unit 26 of the third embodiment and the piezoelectric transformer 161 of the step-up unit 16 of the present embodiment are the same. It is a piezoelectric transformer, and it is preferable that the piezoelectric transformer 262 of the step-down unit 26 of the third embodiment and the piezoelectric transformer 162 of the step-up unit 16 of the present embodiment are the same piezoelectric transformer. In this case, the capacity ratio can be made substantially the same between the power transmission device and the power reception device, and the reference potential of the power reception device can be further stabilized.
  • FIG. 10 is a circuit diagram of the wireless power transmission system 5 according to the fifth embodiment.
  • the power transmission device 105 and the power reception device 205 included in the wireless power transmission system 5 include reference potential electrodes 105A and 205A connected to respective reference potentials.
  • the reference potential electrodes 105A and 205A face each other to form a capacitor Cg. Therefore, the reference potential of the power receiving device 205 is connected to the reference potential of the power transmission device 105 via the formed capacitor Cg.
  • the power transmission device 105 includes a boosting unit 17 that boosts an AC voltage from the power supply circuit 11 and applies the boosted voltage to the active electrode 13 and the passive electrode 14.
  • the booster unit 17 has two piezoelectric transformers 171 and 172.
  • the piezoelectric transformer 171 corresponds to a “third piezoelectric transformer” according to the present invention, and the piezoelectric transformer 171 corresponds to a “fourth piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 171 includes a first electrode E51, a second electrode E52, a third electrode E53, and a fourth electrode E54.
  • the piezoelectric transformer 172 includes a first electrode E61, a second electrode E62, a third electrode E63, and a fourth electrode E64.
  • the first electrodes E51 and E61 correspond to “first voltage input electrodes” according to the present invention.
  • the second electrodes E52 and E62 correspond to the “second voltage input electrode” according to the present invention.
  • the third electrodes E53 and E63 correspond to the “first voltage output electrode” according to the present invention.
  • the fourth electrodes E54 and E64 correspond to the “second voltage output electrode” according to the present invention.
  • the first electrode E51 and the second electrode E52 of the piezoelectric transformer 171 are connected to the power supply circuit 11.
  • the third electrode E53 is connected to the active electrode 13.
  • the fourth electrode E54 is connected to the third electrode E63 of the piezoelectric transformer 172 and the reference potential of the power transmission device 105.
  • the first electrode E61 and the second electrode E62 of the piezoelectric transformer 172 are connected to the power supply circuit 11.
  • the third electrode E63 is connected to the fourth electrode E54 of the piezoelectric transformer 171 and the reference potential of the power transmission device 105.
  • the fourth electrode E64 is connected to the passive electrode 14.
  • the second electrode E52 of the piezoelectric transformer 171 and the first electrode E61 of the piezoelectric transformer 172 are connected to the power supply circuit 11, respectively, but the second electrode E52 of the piezoelectric transformer 171 and the first electrode of the piezoelectric transformer 172 are connected.
  • the electrode E61 may be connected to each other.
  • a parasitic capacitance (capacitor) is generated between the electrodes.
  • a parasitic capacitance generated between the first electrode E51 and the second electrode E52 of the piezoelectric transformer 171 is represented by C31
  • a parasitic capacitance generated between the third electrode E53 and the fourth electrode E54 is represented by C32.
  • a parasitic capacitance generated between the first electrode E51 and the second electrode E52 and the third electrode E53 and the fourth electrode E54 is represented by C33.
  • the parasitic capacitance generated between the first electrode E61 and the second electrode E62 of the piezoelectric transformer 172 is represented by C41
  • the parasitic capacitance generated between the third electrode E63 and the fourth electrode E64 is represented by C42
  • a parasitic capacitance generated between the first electrode E61 and the second electrode E62 and between the third electrode E63 and the fourth electrode E64 is represented by C43.
  • the power receiving device 205 includes a step-down unit 27 that steps down the voltage induced in the active electrode 23 and the passive electrode 24 and supplies the voltage to the diode bridge DB.
  • the step-down unit 27 has two piezoelectric transformers 271 and 272.
  • the piezoelectric transformer 271 corresponds to a “first piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 272 corresponds to a “second piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 271 includes a first electrode E71, a second electrode E72, a third electrode E73, and a fourth electrode E74.
  • the piezoelectric transformer 272 includes a first electrode E81, a second electrode E82, a third electrode E83, and a fourth electrode E84.
  • the first electrodes E71 and E81 correspond to the “first voltage input electrode” according to the present invention.
  • the second electrodes E72 and E82 correspond to the “second voltage input electrode” according to the present invention.
  • the third electrodes E73 and E83 correspond to the “first voltage output electrode” according to the present invention.
  • the fourth electrodes E74 and E84 correspond to the “second voltage output electrode” according to the present invention.
  • the first electrode E71 of the piezoelectric transformer 271 is connected to the active electrode 23.
  • the second electrode E72 is connected to the first electrode E81 of the piezoelectric transformer 272 and the reference potential of the power receiving device 205.
  • the third electrode E73 and the fourth electrode E74 are connected to the diode bridge DB.
  • the first electrode E81 of the piezoelectric transformer 272 is connected to the second electrode E72 of the piezoelectric transformer 271 and the reference potential of the power receiving device 205.
  • the second electrode E82 is connected to the passive electrode 24.
  • the third electrode E83 and the fourth electrode E84 are connected to the diode bridge DB.
  • the fourth electrode E74 of the piezoelectric transformer 271 and the third electrode E83 of the piezoelectric transformer 272 are connected to the diode bridge DB, respectively, the fourth electrode E74 of the piezoelectric transformer 271 and the third electrode of the piezoelectric transformer 272 are connected.
  • the electrode E83 may be connected to each other.
  • parasitic capacitance is generated between the electrodes.
  • a parasitic capacitance generated between the first electrode E71 and the second electrode E72 of the piezoelectric transformer 271 is represented by C51
  • a parasitic capacitance generated between the third electrode E73 and the fourth electrode E74 is represented by C52
  • the parasitic capacitance generated between the first electrode E71 and the second electrode E72 and the third electrode E73 and the fourth electrode E74 is represented by C53.
  • the parasitic capacitance generated between the first electrode E81 and the second electrode E82 of the piezoelectric transformer 272 is represented by C61
  • the parasitic capacitance generated between the third electrode E83 and the fourth electrode E84 is represented by C62
  • a parasitic capacitance generated between the first electrode E81 and the second electrode E82 and the third electrode E83 and the fourth electrode E84 is represented by C63.
  • the piezoelectric transformers 171, 172, 271, 272 are formed on separate piezoelectric element bodies.
  • the piezoelectric transformers 171, 172, 271, and 272 have the same configuration, and are polarized in the thickness direction of the piezoelectric element body on both the input side and the output side.
  • the piezoelectric transformer 271 will be described.
  • FIG. 11 is a diagram illustrating an example of the piezoelectric transformer 271 according to the fifth embodiment.
  • the piezoelectric transformer 271 includes a piezoelectric body 301 formed by stacking, for example, PZT ceramic sheets.
  • the piezoelectric body 301 has, along the length direction, a high impedance drive unit A1, a low impedance power generation unit A2, and an insulation unit A3 formed between the drive unit A1 and the power generation unit A2. .
  • the piezoelectric body 301 in the driving unit A1 is polarized in the thickness direction.
  • the internal electrodes 302 and 303 are alternately stacked in the thickness direction inside the piezoelectric body 301, and the first electrode E71 and the second electrode E72 are provided on the upper and lower surfaces.
  • the internal electrode 302 is connected to the first electrode E71 by a side electrode 304, and the internal electrode 303 is connected to the second electrode E72 by a side electrode (not shown) formed at a position facing the side electrode 304.
  • the piezoelectric body 301 is polarized in the thickness direction.
  • a plurality of piezoelectric bodies 301 and internal electrodes 305 and 306 are alternately stacked, and a third electrode E73 and a fourth electrode E74 are formed on the upper and lower surfaces.
  • the internal electrode 305 is connected to the third electrode E73 by the side electrode 307.
  • the internal electrode 306 indicated by a broken line is not exposed on the surface side on which the side electrode 307 is formed, but is exposed on the opposite surface side.
  • the internal electrode 306 is connected to the fourth electrode E74 by a side electrode (not shown) formed at a position facing the side electrode 307.
  • the piezoelectric transformer 271 having this structure, when an AC voltage is input to the first electrode E71 and the second electrode E72 of the drive unit A1 and driven, the voltage is stepped down from the third electrode E73 and the fourth electrode E74 of the power generation unit A2. A voltage is output.
  • the step-down and step-up voltage transformation ratios can be set by adjusting the laminated configuration of the drive unit A1 and the power generation unit A2.
  • FIG. 12 is an equivalent circuit diagram of the wireless power transmission system 5 shown in FIG. In FIG. 12, the piezoelectric transformers 171 and 172 of the booster unit 17 and the piezoelectric transformers 271 and 272 of the step-down unit 27 are shown as equivalent circuits.
  • the booster 17 has a transformer 170.
  • the transformer 170 is connected between the power supply circuit 11 and the active electrode 13 and the passive electrode 14.
  • a series circuit of capacitors C33 and C43 generated in the piezoelectric transformers 171 and 172 and a series circuit of capacitors C32 and C42 are connected between the active electrode 13 and the passive electrode 14.
  • the connection points of the capacitors C33 and C43 and the connection points of the capacitors C32 and C42 are respectively connected to the reference potential.
  • the step-down unit 27 has a transformer 270.
  • the transformer 270 is connected between the active electrode 23 and the passive electrode 24 and the diode bridge DB.
  • a series circuit of capacitors C51 and C61 generated in the piezoelectric transformers 271 and 272 and a series circuit of capacitors C53 and C63 are connected between the active electrode 23 and the passive electrode 24.
  • the connection point between the capacitors C51 and C61 and the connection point between the capacitors C53 and C63 are connected to a reference potential.
  • the capacitors C52 and C62 generated in the piezoelectric transformers 271 and 272 are not shown.
  • the booster unit 17 of the power transmission device 105 can be equivalently expressed as a configuration in which the capacitors C32 and C33 connected in parallel and the capacitors C42 and C43 connected in parallel are connected in series.
  • capacitors C51 and C53 connected in parallel and capacitors C61 and C63 connected in parallel can be equivalently expressed as a series connection.
  • the capacitances of the capacitors C32, C33, C42, C43, C51, C53, C61, and C63 are represented by C32, C33, C42, C43, C51, C53, C61, and C63, respectively.
  • the capacitors C32, C33, C42, and C43 shown in FIG. 12 can be expressed by a configuration in which a capacitor having a capacitance of C32 + C33 and a capacitor having a capacitance of C42 + C43 are connected in series.
  • the capacitors C51, C53, C61, and C63 shown in FIG. 12 have a configuration in which a capacitor having a capacitance of C51 + C53 and a capacitor having a capacitance of C61 + C63 are connected in series.
  • the area of the passive electrodes 14 and 24 is larger than or equal to the area of the active electrodes 13 and 23, and the relationship of Caa ⁇ Cpp is established.
  • the piezoelectric transformers 171, 172, 271, and 272 are selected so that C32 + C33 ⁇ C42 + C43 and C51 + C53 ⁇ C61 + C63 are satisfied.
  • variation of the reference electric potential of the power receiving apparatus 205 can be suppressed.
  • problems due to fluctuations in the reference potential, for example, malfunction of the device can be prevented.
  • FIG. 13 is a diagram for explaining a method for measuring the parasitic capacitance generated in the piezoelectric transformer 271.
  • a method for measuring the parasitic capacitance generated in the piezoelectric transformer 271 is described, but the method for measuring the parasitic capacitance generated in the other piezoelectric transformers 171, 172, 272 is the same.
  • the constant current source 150 is connected to the first electrode E71 of the piezoelectric transformer 271 and the second electrode E72 is connected to the ground.
  • the third electrode E73 and the fourth electrode E74 are short-circuited and connected to the ground.
  • the capacitor C51 generated in the piezoelectric transformer 271 is a capacitance generated between the first electrode E71 and the second electrode E72
  • the capacitor C52 is a capacitance generated between the third electrode E73 and the fourth electrode E74. Therefore, for example, the capacitance of the capacitor C51 can be obtained by measuring the capacitance between the first electrode E71 and the second electrode E72. Further, the capacitance of the capacitor C52 is obtained by measuring the capacitance between the third electrode E73 and the fourth electrode E74.
  • each of the power transmission device 105 and the power reception device 205 is configured to include a piezoelectric transformer, but only one of the power transmission device 105 and the power reception device 205 may include a piezoelectric transformer.
  • the step-down unit 27 of the power reception device 205 is configured by a winding transformer.
  • the piezoelectric transformers 171 and 172 are selected so as to satisfy C32 + C33 ⁇ C42 + C43.
  • the booster unit 17 of the power transmitting device 105 includes a winding transformer.
  • the piezoelectric transformers 271 and 272 are selected so as to satisfy C51 + C53 ⁇ C61 + C63.
  • the input electrode E72 of the piezoelectric transformer 271 and the input electrode E81 of the piezoelectric transformer 272 are connected to the reference potential, respectively. Good.
  • the input electrode side and the output electrode side of the piezoelectric transformers 271 and 272 are in an insulated state, noise flowing into the input electrode side via the ground can be suppressed.
  • the variation of the reference potential of the power receiving device 205 can be suppressed by selecting the piezoelectric transformers 271 and 272 so as to satisfy C53 ⁇ C63.
  • the fourth electrode E54 of the piezoelectric transformer 171 and the third electrode E63 of the piezoelectric transformer 172 may not be connected to the reference potential of the power transmission device 105.
  • the variation in the reference potential of the power receiving device 205 can be suppressed by selecting the piezoelectric transformers 171 and 172 to satisfy C33 ⁇ C43.
  • the input / output unit uses a piezoelectric transformer that is polarized in the thickness direction of the piezoelectric element body, whereas in the present embodiment, either the input unit or the output unit is a piezoelectric element element.
  • This embodiment is different from the fifth embodiment in that a piezoelectric transformer is used which is polarized in the longitudinal direction and the other is polarized in the thickness direction.
  • differences from the fifth embodiment will be described.
  • FIG. 14 is a circuit diagram of the wireless power transmission system 6 according to the sixth embodiment.
  • the power transmission device 106 included in the wireless power transmission system 6 includes a boosting unit 18 that boosts the AC voltage from the power supply circuit 11 and applies the boosted voltage to the active electrode 13 and the passive electrode 14.
  • the booster 18 has two piezoelectric transformers 181 and 182.
  • the piezoelectric transformer 181 corresponds to a “third piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 182 corresponds to a “fourth piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 181 includes a first electrode E91, a second electrode E92, a third electrode E93, and a fourth electrode E94.
  • the piezoelectric transformer 172 includes a first electrode E101, a second electrode E102, a third electrode E103, and a fourth electrode E104.
  • the first electrodes E91 and E101 correspond to “first voltage input electrodes” according to the present invention.
  • the second electrodes E92 and E102 correspond to the “second voltage input electrode” according to the present invention.
  • the third electrodes E93 and E103 correspond to the “first voltage output electrode” according to the present invention.
  • the fourth electrodes E94 and E104 correspond to the “second voltage output electrode” according to the present invention.
  • the first electrode E91 and the second electrode E92 of the piezoelectric transformer 181 are connected to the power supply circuit 11.
  • the first electrode E91 is also connected to the reference potential of the power transmission device 106.
  • the third electrode E93 is connected to the active electrode 13.
  • the fourth electrode E94 is connected to the third electrode E103 of the piezoelectric transformer 182 and the reference potential of the power transmission device 106.
  • the first electrode E101 and the second electrode E102 of the piezoelectric transformer 182 are connected to the power supply circuit 11.
  • the first electrode E101 is also connected to the reference potential of the power transmission device 106.
  • the fourth electrode E104 is connected to the passive electrode.
  • the third electrode E103 is connected to the fourth electrode E94 of the piezoelectric transformer 181 and the reference potential of the power transmission device 106.
  • parasitic capacitance is generated between the electrodes.
  • a parasitic capacitance generated between the first electrode E91 and the second electrode E92 of the piezoelectric transformer 181 and the third electrode E93 is represented by Ca1, and between the first electrode E91, the second electrode E92, and the fourth electrode E94.
  • the resulting parasitic capacitance is represented by Cb1.
  • a parasitic capacitance generated between the first electrode E91 and the second electrode E92 is represented by Cc1.
  • a parasitic capacitance generated between the first electrode E101 and the second electrode E102 of the piezoelectric transformer 182 and the third electrode E103 is represented by Ca2
  • the first electrode E101, the second electrode E102, the fourth electrode E104, The parasitic capacitance generated during the period is represented by Cb2.
  • a parasitic capacitance generated between the first electrode E101 and the second electrode E102 is represented by Cc2.
  • the power receiving device 206 included in the wireless power transmission system 6 includes a step-down unit 28 that steps down the voltage induced in the active electrode 23 and the passive electrode 24 and supplies the voltage to the diode bridge DB.
  • the step-down unit 28 has two piezoelectric transformers 281 and 282.
  • the piezoelectric transformer 281 corresponds to a “first piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 282 corresponds to a “second piezoelectric transformer” according to the present invention.
  • the piezoelectric transformer 281 includes a first electrode E111, a second electrode E112, a third electrode E113, and a fourth electrode E114.
  • the piezoelectric transformer 282 includes a first electrode E121, a second electrode E122, a third electrode E123, and a fourth electrode E124.
  • the first electrodes E111 and E121 correspond to “first voltage output electrodes” according to the present invention.
  • the second electrodes E112 and E122 correspond to the “second voltage output electrode” according to the present invention.
  • the third electrodes E113 and E123 correspond to the “first voltage input electrode” according to the present invention.
  • the fourth electrodes E114 and E124 correspond to “second voltage input electrodes” according to the invention.
  • the first electrode E111 and the second electrode E112 of the piezoelectric transformer 281 are connected to the diode bridge DB.
  • the third electrode E113 is connected to the active electrode 23.
  • the fourth electrode E114 is connected to the third electrode E123 of the piezoelectric transformer E282 and the reference potential of the power receiving device 206.
  • the first electrode E121 and the second electrode E122 of the piezoelectric transformer 282 are connected to the diode bridge DB.
  • the fourth electrode E124 is connected to the passive electrode 24.
  • the third electrode E123 is connected to the fourth electrode E114 of the piezoelectric transformer E281 and the reference potential of the power receiving device 206.
  • parasitic capacitance is generated between the electrodes.
  • a parasitic capacitance generated between the first electrode E111 and the second electrode E112 of the piezoelectric transformer 281 and the third electrode E113 is represented by Ca3, and between the first electrode E111, the second electrode E112, and the fourth electrode E114.
  • the resulting parasitic capacitance is represented by Cb3.
  • a parasitic capacitance generated between the first electrode E111 and the second electrode E112 is represented by Cc3.
  • a parasitic capacitance generated between the first electrode E121 and the second electrode E122 of the piezoelectric transformer 282 and the third electrode E123 is represented by Ca4, and the first electrode E121, the second electrode E122, and the fourth electrode E124 The parasitic capacitance generated during the period is represented by Cb4. Further, the parasitic capacitance generated between the first electrode E121 and the second electrode E122 is represented by Cc4.
  • the piezoelectric transformers 181, 182, 281 and 282 are piezoelectric transformers in which one of the input unit and the output unit is polarized in the longitudinal direction of the piezoelectric body and the other is polarized in the thickness direction.
  • Each of the piezoelectric transformers 181, 182, 281, and 282 has the same configuration, and the piezoelectric transformer 281 will be described below.
  • FIG. 15 is a diagram illustrating an example of the piezoelectric transformer 281 according to the sixth embodiment.
  • the piezoelectric transformer 281 includes a piezoelectric body 401 formed by stacking, for example, PZT ceramic sheets.
  • the piezoelectric transformer 281 vibrates in the length direction in the (3 ⁇ / 2) resonance mode.
  • ⁇ is one wavelength of vibration in the length direction. Therefore, the length of the piezoelectric body 401 is (3 ⁇ / 2).
  • the width and thickness of the piezoelectric body 401 are preferably less than ( ⁇ / 2). By doing so, the vibration in the width direction and the thickness direction is not coupled to the vibration in the length direction, and the vibration of the entire piezoelectric transformer 281 is not unstable.
  • the piezoelectric body 401 has a first region B1, a second region B2, and a third region B3. Each of the regions B1 to B3 has a length of ⁇ / 2.
  • the first region B1 and the third region B3 are polarized in parallel with the length direction of the piezoelectric body, and the second region B2 is polarized in parallel with the thickness direction.
  • the first region B1 and the third region B3 are polarized in opposite directions.
  • Examples of the polarization treatment method include a method of applying a voltage of 2 kV / mm to the piezoelectric plate in insulating oil at 170 ° C.
  • the first electrode E111 and the second electrode E112 are provided to face the side surface of the piezoelectric body 401.
  • the second region B2 is provided with a plurality of internal electrodes 402 stacked in the thickness direction.
  • the internal electrodes 402 are alternately connected to the first electrode E111 and the second electrode E112.
  • a pair of third electrodes E113A and 113B are provided in the first region B1 so as to face the side surface of the piezoelectric body 401.
  • the pair of third electrodes E113A and 113B corresponds to the third electrode E113 shown in FIG.
  • a plurality of internal electrodes 403 stacked in the thickness direction are provided in the first region B1. All of the internal electrodes 403 are connected to both the third electrodes E113A and 113B.
  • a pair of fourth electrodes E114A and 114B are provided to face the side surface of the piezoelectric body 401.
  • the pair of fourth electrodes E114A and 114B corresponds to the fourth electrode E114 shown in FIG.
  • a plurality of internal electrodes 404 stacked in the thickness direction are provided. All of the internal electrodes 404 are connected to both the fourth electrodes E114A and 114B.
  • the piezoelectric transformer 281 configured as described above, when voltage is input from the pair of third electrodes E113A and 113B and the pair of fourth electrodes E114A and 114B, the first region B1 and the third region B3 An electric field is applied in the polarization direction (length direction). Then, longitudinal vibration is excited in the polarization direction, that is, the length direction of the piezoelectric body 401 by the inverse piezoelectric effect. When longitudinal vibration is excited, mechanical distortion occurs in the polarization direction in the second region B2, and a potential difference occurs in the polarization direction due to the piezoelectric transverse effect. Due to this potential difference, the second region B2 becomes a low voltage portion, and a low voltage is extracted from the first electrode E111 and the second electrode E112 in the second region B2.
  • the relationship between the parasitic capacitance generated in the piezoelectric transformers 181, 182, 281, and 282 according to the present embodiment and the parasitic capacitance generated in the piezoelectric transformers 171, 172, 271, and 272 according to the fifth embodiment will be described.
  • the relationship between the capacitors Ca3, Cb3, Cc3 generated in the piezoelectric transformer 281 according to the present embodiment and the capacitors C51, C52, C53 (see FIG. 10) generated in the piezoelectric transformer 271 according to the fifth embodiment is taken as an example. explain.
  • the capacitors Ca1, Cb1, and Cc1 generated in the piezoelectric transformer 181 have the same correspondence relationship as the capacitors C31, C32, and C33 generated in the piezoelectric transformer 171.
  • the capacitors Ca2, Cb2, and Cc2 generated in the piezoelectric transformer 182 have the same correspondence relationship as the capacitors C41, C42, and C43 generated in the piezoelectric transformer 172.
  • the capacitors Ca4, Cb4, and Cc4 generated in the piezoelectric transformer 282 have the same correspondence relationship as the capacitors C61, C62, and C63 generated in the piezoelectric transformer 272.
  • the piezoelectric transformers 181, 182, 281, and 282 are selected so as to satisfy C32 + C33 ⁇ C42 + C43 and C51 + C53 ⁇ C61 + C63. Thereby, the fluctuation
  • FIG. 16 is a diagram for explaining a method for measuring a capacitor generated in the piezoelectric transformer 281.
  • FIG. 16 only the method for measuring the capacitor generated in the piezoelectric transformer 281 is described, but the method for measuring the capacitor generated in the other piezoelectric transformers 181, 182, and 282 is the same.
  • the constant current source 150 is connected to the third electrode E113 of the piezoelectric transformer 281 and the fourth electrode E114 is connected to the ground.
  • the first electrode E111 and the second electrode E112 are short-circuited and connected to the ground.
  • the capacitance when the capacitors Ca3 and Cb3 are connected in series can be measured.
  • Piezoelectric transformer (second piezoelectric transformer)
  • C11 Capacitor (first capacitance)
  • C12 Capacitor (second capacitance)
  • C13 Capacitor (third capacitance)
  • C14 Capacitor (fourth capacitance)
  • C15 Capacitor (input capacitance of the first piezoelectric transformer)
  • C16 Capacitor (input capacitance of the second piezoelectric transformer)
  • C17 Capacitor (input capacitance of the third piezoelectric transformer)
  • C18 Capacitor (input capacitance of the fourth piezoelectric transformer)
  • Co ... capacitor Ca Cp ... capacitor DB ... diode bridge E11, E21 ...

Abstract

A step-down section (25) that is provided in a power reception apparatus (201) is provided with winding transformers (T21, T22), said power reception apparatus having power transmitted thereto from a power transmission apparatus (101) by means of electric field-coupling. Primary coils of the winding transformers (T21, T22) are connected in series, and a connection point is connected to a reference potential of the power reception apparatus (201). When an electrostatic capacitance generated in the primary coil of the winding transformer (T21) is expressed as (C11), and an inductance is expressed as (L11), an electrostatic capacitance generated between the primary coils of the winding transformer (T21) is expressed as (C12), and an inductance is expressed as (L12), the winding transformers (T11, T12) are selected such that the condition of C11≤C12 is satisfied in the cases where 1/ωC11<ωL11 and 1/ωC12<ωL12, and the condition of L11≥L12 is satisfied in the cases where 1/ωC11>ωL11 and 1/ωC12>ωL12. Consequently, the power reception apparatus wherein a ratio between capacitances generated in a high-potential section and a low-potential section can be easily set in order to suppress fluctuation of the reference potential, a power transmission apparatus, and a wireless power transmission system are provided.

Description

送電装置、受電装置及びワイヤレス電力伝送システムPower transmission device, power reception device, and wireless power transmission system
　本発明は、電界結合方式によりワイヤレスで電力を伝送する送電装置、受電装置及びワイヤレス電力伝送システムに関する。 The present invention relates to a power transmission device, a power reception device, and a wireless power transmission system that transmit power wirelessly by an electric field coupling method.
　近年、携帯電話機、又はモバイルＰＣなどの電子機器を充電する際、電子機器に充電用のケーブルを接続するといった煩わしさを無くすために、充電装置に電子機器を設置するだけで充電できるワイヤレス電力伝送が提案されている。ワイヤレス電力伝送として、電界結合を利用して送電装置（充電装置）側から受電装置（電子機器）側へ電力を伝送する方式が知られている（例えば、特許文献１参照）。 In recent years, when charging an electronic device such as a mobile phone or a mobile PC, wireless power transmission can be performed simply by installing the electronic device in the charging device in order to eliminate the trouble of connecting a charging cable to the electronic device. Has been proposed. As wireless power transmission, a method of transmitting electric power from a power transmission device (charging device) side to a power reception device (electronic device) side using electric field coupling is known (for example, see Patent Document 1).
　特許文献１に記載の電力伝送システムでは、送電装置、及び受電装置それぞれに高電位側となるアクティブ電極と、低電位側となるパッシブ電極とを備え、アクティブ電極同士、及びパッシブ電極同士を、間隙を介して対向させることで電極間に強い電界を形成し、電極同士を電界結合させる。この電界結合により装置間でのワイヤレスな電力伝送を可能としている。 In the power transmission system described in Patent Document 1, each of the power transmitting device and the power receiving device includes an active electrode on the high potential side and a passive electrode on the low potential side, and the active electrodes and the passive electrodes are separated by a gap. A strong electric field is formed between the electrodes by making them face each other, and the electrodes are electric field coupled. This electric field coupling enables wireless power transmission between devices.
特表２００９－５３１００９号公報JP-T 2009-531009
　この電界結合方式のワイヤレス電力伝送システムでは、アクティブ電極同士に印加される電圧を相対的に高くし、パッシブ電極同士に印加される電圧を相対的に低くして電力伝送される。このため、基準電位に対するアクティブ電極の電位の絶対値と、基準電位に対するパッシブ電極の電位の絶対値との差は大きい。この場合、装置の基準電位とアクティブ電極（高電位部）との間に形成される容量と、装置の基準電位とパッシブ電極（低電位部）との間に形成される容量との容量比が適切な値に設定されていないと、受電装置の基準電位が変動するおそれがある。そして、基準電位が変動すると、それに伴い、受電装置において不具合が生じるおそれがある。 In this electric field coupling type wireless power transmission system, power is transmitted with a relatively high voltage applied between the active electrodes and a relatively low voltage applied between the passive electrodes. For this reason, the difference between the absolute value of the potential of the active electrode with respect to the reference potential and the absolute value of the potential of the passive electrode with respect to the reference potential is large. In this case, the capacitance ratio between the capacitance formed between the reference potential of the device and the active electrode (high potential portion) and the capacitance formed between the reference potential of the device and the passive electrode (low potential portion) is If it is not set to an appropriate value, the reference potential of the power receiving apparatus may fluctuate. If the reference potential fluctuates, a problem may occur in the power receiving apparatus.
　この問題を回避するために、変動する容量比を調整する回路を構成することが考えられるが、この場合、外付け部品により省スペース化を阻害するといった問題が生じる。また、装置の回路又は素子の設計変更を必要とし、手間を要するといった問題も生じる。このため、高電位部と低電位部とに生じる容量の比を、容易に調整することは難しい。 In order to avoid this problem, it is conceivable to construct a circuit that adjusts the changing capacitance ratio. In this case, however, there arises a problem that space saving is hindered by external parts. In addition, there is a problem in that it requires a design change of the circuit or element of the apparatus, which takes time. For this reason, it is difficult to easily adjust the ratio of the capacitance generated between the high potential portion and the low potential portion.
　そこで、本発明の目的は、基準電位の変動を抑制するために、高電位部と低電位部とに生じる容量の比を容易に設定できる受電装置、送電装置及びワイヤレス電力伝送システムを提供することにある。 Accordingly, an object of the present invention is to provide a power receiving device, a power transmitting device, and a wireless power transmission system in which a ratio of capacities generated in a high potential portion and a low potential portion can be easily set in order to suppress a change in reference potential. It is in.
　本発明に係る受電装置は、送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、前記第１トランスは、１次コイル及び２次コイルを有し、前記１次コイルの第１端が前記受電側アクティブ電極に接続され、第２端が自装置の基準電位に接続された第１巻線トランスと、１次コイル、及び２次コイルを有し、前記１次コイルの第１端が前記受電側パッシブ電極に接続され、第２端が自装置の基準電位に接続された第２巻線トランスと、を有し、前記第１巻線トランスの前記１次コイルのインダクタンスをＬ１１、前記１次コイルの前記第１端と前記第２端との間に生じる第１静電容量をＣ１１、前記第２巻線トランスの１次コイルのインダクタンスをＬ１２、前記１次コイルの前記第１端と前記第２端との間に生じる第２静電容量をＣ１２、電力伝送の動作角周波数をωで表すと、１／ωＣ１１＜ωＬ１１、１／ωＣ１２＜ωＬ１２である場合、Ｃ１１≦Ｃ１２であり、１／ωＣ１１＞ωＬ１１、１／ωＣ１２＞ωＬ１２である場合、Ｌ１１≧Ｌ１２であることを特徴とする。 The power receiving device according to the present invention includes a power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side In a power receiving apparatus, comprising: a first transformer to which a voltage induced in a passive electrode is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein power is transmitted from the power transmitting apparatus by electric field coupling. The first transformer has a primary coil and a secondary coil, a first end of the primary coil is connected to the power receiving side active electrode, and a second end is connected to a reference potential of the device itself. It has a single-winding transformer, a primary coil, and a secondary coil. The first end of the primary coil is connected to the passive passive electrode, and the second end is connected to the reference potential of the device. A first winding that is generated between the first end and the second end of the primary coil. The capacitance is C11, the inductance of the primary coil of the second winding transformer is L12, the second capacitance generated between the first end and the second end of the primary coil is C12, power transmission In the case of 1 / ωC11 <ωL11 and 1 / ωC12 <ωL12, C11 ≦ C12, and when 1 / ωC11> ωL11 and 1 / ωC12> ωL12, L11 ≧ L12. It is characterized by being.
　この構成では、各条件を満たすよう、第１巻線トランスと第２巻線トランスとを組み合わせることにより、アクティブ電極（高電位部）とパッシブ電極（低電位部）とに生じる容量比を設定できる。これにより、受電装置の基準電位の変動を抑制して、不具合を防止できる。 In this configuration, the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first winding transformer and the second winding transformer so as to satisfy each condition. . Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
　前記第１静電容量、及び前記第２静電容量は、前記第１巻線トランス、及び前記第２巻線トランスの前記１次コイルの巻線間浮遊容量である、ことが好ましい。 It is preferable that the first capacitance and the second capacitance are stray capacitances between windings of the primary coil of the first winding transformer and the second winding transformer.
　この構成では、巻線トランスの巻線比に応じて、１次コイル及び２次コイルを組み合わせすることで、アクティブ電極（高電位部）とパッシブ電極（低電位部）とに生じる容量比を設定できる。 In this configuration, the capacitance ratio generated between the active electrode (high potential part) and the passive electrode (low potential part) is set by combining the primary coil and the secondary coil according to the winding ratio of the winding transformer. it can.
　本発明は、送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、前記第１トランスは、１次コイル及び２次コイルを有する第１巻線トランス及び第２巻線トランスを有し、前記第１巻線トランスは、前記１次コイルの第１端が前記受電側アクティブ電極に接続され、第２端が前記第２巻線トランスの１次コイルの第１端に接続された構成であり、前記第２巻線トランスは、前記１次コイルの第２端が前記受電側パッシブ電極に接続された構成であり、前記第１巻線トランスの前記１次コイル及び前記２次コイルの間の静電容量をＣ１３、前記第２巻線トランスの前記１次コイル及び前記２次コイルの間の静電容量をＣ１４で表すと、Ｃ１３＜Ｃ１４であることを特徴とする。 The present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode A first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein the first power is transmitted from the power transmission device by electric field coupling. The transformer has a first winding transformer and a second winding transformer having a primary coil and a secondary coil, and the first winding transformer has a first end of the primary coil connected to the power receiving side active electrode. And the second end is connected to the first end of the primary coil of the second winding transformer, and the second end of the primary coil is the front end of the second winding transformer. It is the structure connected to the power receiving side passive electrode, and the electrostatic capacitance between the primary coil and the secondary coil of the first winding transformer is C13, the primary coil of the second winding transformer and the When the capacitance between the secondary coils is represented by C14, C13 <C14.
　この構成では、各条件を満たすよう、第１巻線トランスと第２巻線トランスとを組み合わせることにより、アクティブ電極（高電位部）とパッシブ電極（低電位部）とに生じる容量比を設定できる。これにより、受電装置の基準電位の変動を抑制して、不具合を防止できる。 In this configuration, the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first winding transformer and the second winding transformer so as to satisfy each condition. . Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
　本発明は、送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、前記第１トランスは、電圧入力電極、電圧出力電極、及び、自装置の基準電位に接続される基準電位用電極を有する第１圧電トランス及び第２圧電トランスを有し、前記第１圧電トランスは、前記電圧入力電極が前記受電側アクティブ電極に接続され、前記電圧出力電極が、前記第２圧電トランスの前記電圧出力電極に接続された構成であり、前記第２圧電トランスは、前記電圧入力電極が前記受電側パッシブ電極に接続された構成であり、前記第１圧電トランスの前記電圧入力電極と前記基準電位用電極との間に生じる静電容量をＣ１５、前記第２圧電トランスの前記電圧入力電極と前記基準電位用電極との間に生じる静電容量をＣ１６で表すと、Ｃ１５≦Ｃ１６であることを特徴とする。 The present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode A first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein the first power is transmitted from the power transmission device by electric field coupling. The transformer includes a first piezoelectric transformer and a second piezoelectric transformer having a voltage input electrode, a voltage output electrode, and a reference potential electrode connected to a reference potential of the device itself, and the first piezoelectric transformer includes the voltage An input electrode is connected to the power receiving side active electrode, and the voltage output electrode is connected to the voltage output electrode of the second piezoelectric transformer. The second piezoelectric transformer has a configuration in which the voltage input electrode is connected to the power-receiving-side passive electrode, and an electrostatic charge generated between the voltage input electrode of the first piezoelectric transformer and the reference potential electrode. When the capacitance is expressed as C15 and the capacitance generated between the voltage input electrode and the reference potential electrode of the second piezoelectric transformer is expressed as C16, C15 ≦ C16.
　この構成では、各条件を満たすよう、第１巻線トランスと第２巻線トランスとを組み合わせることにより、アクティブ電極（高電位部）とパッシブ電極（低電位部）とに生じる容量比を設定できる。これにより、受電装置の基準電位の変動を抑制して、不具合を防止できる。また、圧電トランスを用いることで、受電装置の小型化、薄型化を実現できる。 In this configuration, the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first winding transformer and the second winding transformer so as to satisfy each condition. . Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented. In addition, by using a piezoelectric transformer, the power receiving device can be reduced in size and thickness.
　本発明は、送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、前記第１トランスは、第１電圧入力電極、第２電圧入力電極、第１電圧出力電極及び第２電圧出力電極を有する第１圧電トランス及び第２圧電トランスを有し、前記第１圧電トランスは、前記第１電圧入力電極が前記受電側アクティブ電極に接続され、前記第２電圧入力電極が、自装置の基準電位に接続された構成であり、前記第２圧電トランスは、前記第２電圧入力電極が前記受電側パッシブ電極に接続され、前記第１電圧入力電極が、前記第１圧電トランスの前記第２電圧入力電極、及び、自装置の基準電位に接続された構成であり、前記第１圧電トランスの前記第１電圧入力電極と前記第２電圧入力電極との間に生じる静電容量をＣ５１、前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ５３で表し、前記第２圧電トランスの前記第１電圧入力電極と前記第２電圧入力電極との間に生じる静電容量をＣ６１、前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ６３で表すと、Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３であることを特徴とする。 The present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode A first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage excited by the first transformer is applied, wherein the first power is transmitted from the power transmission device by electric field coupling. The transformer includes a first piezoelectric transformer and a second piezoelectric transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode, and a second voltage output electrode, wherein the first piezoelectric transformer One voltage input electrode is connected to the power receiving side active electrode, and the second voltage input electrode is connected to a reference potential of the device itself, and the second piezoelectric The lance has the second voltage input electrode connected to the power-receiving-side passive electrode, the first voltage input electrode connected to the second voltage input electrode of the first piezoelectric transformer, and a reference potential of the device itself. The capacitance generated between the first voltage input electrode and the second voltage input electrode of the first piezoelectric transformer is C51, the first voltage input electrode, the second voltage input electrode, and the A capacitance generated between the first voltage output electrode and the second voltage output electrode is represented by C53, and a static electricity generated between the first voltage input electrode and the second voltage input electrode of the second piezoelectric transformer. The capacitance generated between the first voltage input electrode and the second voltage input electrode and the first voltage output electrode and the second voltage output electrode is represented by C63, and C51 + C53 ≦ C61 + C63. Ah It is characterized in.
　本発明は、送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスによりされた電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、前記第１トランスは、第１電圧入力電極、第２電圧入力電極、第１電圧出力電極及び第２電圧出力電極を有する第１圧電トランス及び第２圧電トランスを有し、前記第１圧電トランスは、前記第１電圧入力電極が前記受電側アクティブ電極に接続された構成であり、前記第２圧電トランスは、前記第２電圧入力電極が前記受電側パッシブ電極に接続され、前記第１電圧入力電極が、前記第１圧電トランスの前記第２電圧入力電極に接続された構成であり、前記第１圧電トランスの前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ５３で表し、前記第２圧電トランスの前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ６３で表すと、Ｃ５３≦Ｃ６３であることを特徴とする。 The present invention is induced on a power receiving side active electrode facing a power transmitting side active electrode of a power transmitting device, a power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, the power receiving side active electrode, and the power receiving side passive electrode A first transformer to which a voltage to be applied is applied; and a load circuit to which a voltage applied by the first transformer is applied, wherein the first transformer Includes a first piezoelectric transformer and a second piezoelectric transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode, and a second voltage output electrode, wherein the first piezoelectric transformer includes the first piezoelectric transformer The voltage input electrode is connected to the power receiving side active electrode, and the second piezoelectric transformer is configured such that the second voltage input electrode is the power receiving side passive electrode. The first voltage input electrode is connected to the second voltage input electrode of the first piezoelectric transformer, and the first voltage input electrode and the second voltage input electrode of the first piezoelectric transformer are connected. A capacitance generated between the first voltage output electrode and the second voltage output electrode is represented by C53, and the first voltage input electrode, the second voltage input electrode, and the first voltage of the second piezoelectric transformer The capacitance generated between the voltage output electrode and the second voltage output electrode is represented by C63, and C53 ≦ C63.
　この構成では、各条件を満たすよう、第１圧電トランスと第２圧電トランスとを組み合わせることにより、アクティブ電極（高電位部）とパッシブ電極（低電位部）とに生じる容量比を設定できる。これにより、受電装置の基準電位の変動を抑制して、不具合を防止できる。また、圧電トランスを用いることで、受電装置の小型化、薄型化を実現できる。 In this configuration, the capacitance ratio generated between the active electrode (high potential portion) and the passive electrode (low potential portion) can be set by combining the first piezoelectric transformer and the second piezoelectric transformer so as to satisfy each condition. Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented. In addition, by using a piezoelectric transformer, the power receiving device can be reduced in size and thickness.
　本発明によれば、第１巻線トランスと第２巻線トランスとを組み合わせることにより、アクティブ電極と基準電位との間に生じる容量と、パッシブ電極と基準電位との間に生じる容量との比を設定できる。これにより、受電装置の基準電位の変動を抑制して、不具合を防止できる。 According to the present invention, by combining the first winding transformer and the second winding transformer, the ratio between the capacitance generated between the active electrode and the reference potential and the capacitance generated between the passive electrode and the reference potential. Can be set. Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed, and a malfunction can be prevented.
実施形態１に係るワイヤレス電力伝送システムの回路図1 is a circuit diagram of a wireless power transmission system according to a first embodiment. 図１に示す受電装置の等価回路を示す図The figure which shows the equivalent circuit of the power receiving apparatus shown in FIG. 一部を省略したワイヤレス電力伝送システムの等価回路図Equivalent circuit diagram of a wireless power transmission system with some parts omitted 降圧部の別の例を示す図The figure which shows another example of the pressure | voltage fall part 降圧部の別の例を示す図The figure which shows another example of the pressure | voltage fall part 降圧部が有する巻線トランスの１次コイルの接続点を、グランド接続しない場合の例を示す図The figure which shows the example in case the connection point of the primary coil of the coil | winding transformer which a step-down part does not connect to the ground 静電容量を説明するための図Diagram for explaining capacitance 実施形態２に係る送電装置の回路図Circuit diagram of power transmission device according to embodiment 2 実施形態３に係るワイヤレス電力伝送システムの受電装置の回路図Circuit diagram of power receiving device of wireless power transmission system according to embodiment 3 実施形態４に係る送電装置の回路図Circuit diagram of power transmission device according to Embodiment 4 実施形態５に係るワイヤレス電力伝送システムの回路図Circuit diagram of wireless power transmission system according to Embodiment 5 実施形態５に係る圧電トランスの一例を示す図FIG. 10 is a diagram illustrating an example of a piezoelectric transformer according to a fifth embodiment. 図１０に示すワイヤレス電力伝送システムの等価回路図Equivalent circuit diagram of the wireless power transmission system shown in FIG. 圧電トランスに生じる寄生容量の測定方法を説明するための図Diagram for explaining a method for measuring parasitic capacitance generated in a piezoelectric transformer 実施形態６に係るワイヤレス電力伝送システムの回路図Circuit diagram of wireless power transmission system according to Embodiment 6 実施形態６に係る圧電トランスの一例を示す図FIG. 10 is a diagram illustrating an example of a piezoelectric transformer according to a sixth embodiment. 圧電トランスに生じるキャパシタの測定方法を説明するための図The figure for explaining the measuring method of the capacitor which occurs in the piezoelectric transformer
（実施形態１）
　図１は、実施形態１に係るワイヤレス電力伝送システム１の回路図である。ワイヤレス電力伝送システム１は、送電装置１０１と受電装置２０１とを備えている。送電装置１０１には受電装置２０１が載置される。その状態で、送電装置１０１は、電界結合を利用して受電装置２０１へ電力を伝送する。受電装置２０１は、二次電池及び充電回路を含む負荷回路ＲＬを備えていて、送電装置１０１から送電された電力を二次電池に充電する。 (Embodiment 1)
FIG. 1 is a circuit diagram of a wireless power transmission system 1 according to the first embodiment. The wireless power transmission system 1 includes a power transmission device 101 and a power reception device 201. A power receiving apparatus 201 is placed on the power transmitting apparatus 101. In that state, the power transmission apparatus 101 transmits electric power to the power reception apparatus 201 using electric field coupling. The power receiving apparatus 201 includes a load circuit RL including a secondary battery and a charging circuit, and charges the secondary battery with the power transmitted from the power transmitting apparatus 101.
　送電装置１０１は電源回路１１を備えている。電源回路１１は、商用電源に接続されたＡＣアダプタにより交流電圧（ＡＣ１００Ｖ～２４０Ｖ）から変換された直流電圧（例えばＤＣ１９Ｖ）を、ＤＣ－ＡＣインバータ回路で交流電圧に変換する。 The power transmission device 101 includes a power circuit 11. The power supply circuit 11 converts a DC voltage (for example, DC 19 V) converted from an AC voltage (AC 100 V to 240 V) by an AC adapter connected to a commercial power source into an AC voltage using a DC-AC inverter circuit.
　電源回路１１には昇圧トランス１２が接続されている。昇圧トランス１２は、１次コイル及び２次コイルを有する絶縁型巻線トランスである。１次コイルは電源回路１１に接続されている。２次コイルの一端はアクティブ電極１３に接続され、他端はパッシブ電極１４に接続されている。 A step-up transformer 12 is connected to the power circuit 11. The step-up transformer 12 is an insulated winding transformer having a primary coil and a secondary coil. The primary coil is connected to the power supply circuit 11. One end of the secondary coil is connected to the active electrode 13, and the other end is connected to the passive electrode 14.
　アクティブ電極１３及びパッシブ電極１４はいずれも平板状であり、アクティブ電極１３はパッシブ電極１４よりも面積が同じ又は小さい。そして、アクティブ電極１３はパッシブ電極１４よりも送電装置１０１の基準電位に対して電位差が同じ又は大きい。これらアクティブ電極１３及びパッシブ電極１４には、昇圧トランス１２で昇圧された交流電圧が印加される。 The active electrode 13 and the passive electrode 14 are both flat, and the active electrode 13 has the same or smaller area than the passive electrode 14. The active electrode 13 has the same or larger potential difference than the passive electrode 14 with respect to the reference potential of the power transmission device 101. An alternating voltage boosted by the step-up transformer 12 is applied to the active electrode 13 and the passive electrode 14.
　アクティブ電極１３及びパッシブ電極１４の間には、キャパシタＣ１ａ，Ｃ１ｐが直列に接続されている。キャパシタＣ１ａ，Ｃ１ｐの接続点は、送電装置１０１の基準電位に接続されている。また、キャパシタＣ１ａの容量（以下、Ｃ１ａで表す）は、キャパシタＣ１ｐの容量（以下、Ｃ１ｐで表す）より小さい又は等しく、Ｃ１ａ≦Ｃ１ｐの関係が成り立つ。このキャパシタＣ１ａ，Ｃ１ｐは、基準電位の変動を抑制するものであり、詳しくは後述する。 Between the active electrode 13 and the passive electrode 14, capacitors C1a and C1p are connected in series. The connection point of the capacitors C1a and C1p is connected to the reference potential of the power transmission device 101. Further, the capacitance of the capacitor C1a (hereinafter referred to as C1a) is smaller than or equal to the capacitance of the capacitor C1p (hereinafter referred to as C1p), and the relationship of C1a ≦ C1p is established. The capacitors C1a and C1p suppress fluctuations in the reference potential and will be described in detail later.
　受電装置２０１は、アクティブ電極２３及びパッシブ電極２４を備えている。受電装置２０１を送電装置１０１に載置した場合に、アクティブ電極２３は、送電装置１０１のアクティブ電極１３に対向し、パッシブ電極２４は、送電装置１０１のパッシブ電極１４に対向する。アクティブ電極２３及びパッシブ電極２４はいずれも平板状であり、アクティブ電極２３は、対向するアクティブ電極１３と同面積を有し、パッシブ電極２４は、対向するパッシブ電極１４と同面積を有している。すなわち、アクティブ電極２３はパッシブ電極２４よりも面積が小さい、又は同じである。そして、アクティブ電極２３はパッシブ電極２４よりも受電装置２０１の基準電位に対して電位差が大きい、又は同じである。 The power receiving apparatus 201 includes an active electrode 23 and a passive electrode 24. When the power receiving apparatus 201 is placed on the power transmission apparatus 101, the active electrode 23 faces the active electrode 13 of the power transmission apparatus 101, and the passive electrode 24 faces the passive electrode 14 of the power transmission apparatus 101. The active electrode 23 and the passive electrode 24 are both flat, the active electrode 23 has the same area as the opposing active electrode 13, and the passive electrode 24 has the same area as the opposing passive electrode 14. . That is, the active electrode 23 has a smaller area or the same area as the passive electrode 24. The active electrode 23 has a larger potential difference or the same potential as the reference potential of the power receiving device 201 than the passive electrode 24.
　以下では、アクティブ電極１３，２３の間に生じる（等価的に接続される）容量をキャパシタＣａで表し、パッシブ電極１４，２４の間に生じる（等価的に接続される）容量をキャパシタＣｐで表す。また、キャパシタＣａのキャパシタンスをＣａａ、キャパシタＣｐのキャパシタンスをＣｐｐで表す。この場合、パッシブ電極１４，２４間の対向面積は、アクティブ電極１３，２３間の対向面積よりも大きい、又は同じであるから、Ｃａａ≦Ｃｐｐの関係が成り立つ。 In the following, the capacitance generated (equivalently connected) between the active electrodes 13 and 23 is represented by a capacitor Ca, and the capacitance generated (equivalently connected) between the passive electrodes 14 and 24 is represented by a capacitor Cp. . The capacitance of the capacitor Ca is represented by Caa, and the capacitance of the capacitor Cp is represented by Cpp. In this case, since the facing area between the passive electrodes 14 and 24 is larger than or the same as the facing area between the active electrodes 13 and 23, a relationship of Caa ≦ Cpp is established.
　なお、アクティブ電極２３及びパッシブ電極２４は、対向するアクティブ電極１３及びパッシブ電極１４と同面積を有しているとしているが、これに限らない。アクティブ電極１３，２３間の対向面積が、パッシブ電極１４，２４間の対向面積より小さい、または同じであるように電極の大きさを定め、Ｃａａ≦Ｃｐｐの関係が成り立てばよい。 The active electrode 23 and the passive electrode 24 have the same area as the active electrode 13 and the passive electrode 14 facing each other. However, the present invention is not limited to this. The size of the electrodes is determined so that the facing area between the active electrodes 13 and 23 is smaller than or equal to the facing area between the passive electrodes 14 and 24, and the relationship of Caa ≦ Cpp may be established.
　アクティブ電極２３及びパッシブ電極２４には、降圧部２５、整流用のダイオードブリッジＤＢ、平滑用のインダクタＬ１及びキャパシタＣｏを介して、負荷回路ＲＬが接続されている。送電装置１０１のアクティブ電極１３及びパッシブ電極１４に電圧が印加されると、アクティブ電極１３，２３同士、パッシブ電極１４，２４同士が電界結合する。そして、アクティブ電極２３及びパッシブ電極２４には電圧が誘起される。降圧部２５は、この誘起された電圧を降圧する。降圧部２５は、本発明に係る「第１トランス」に相当する。 A load circuit RL is connected to the active electrode 23 and the passive electrode 24 via a step-down unit 25, a rectifying diode bridge DB, a smoothing inductor L1, and a capacitor Co. When a voltage is applied to the active electrode 13 and the passive electrode 14 of the power transmission device 101, the active electrodes 13 and 23 and the passive electrodes 14 and 24 are electrically coupled. A voltage is induced in the active electrode 23 and the passive electrode 24. The step-down unit 25 steps down the induced voltage. The step-down unit 25 corresponds to a “first transformer” according to the present invention.
　降圧部２５は、二つの巻線トランスＴ２１，Ｔ２２を有している。巻線トランスＴ２１は、本発明に係る第１巻線トランスに相当し、巻線トランスＴ２２は、本発明に係る第２巻線トランスに相当する。巻線トランスＴ２１，Ｔ２２は、１次コイルと２次コイルとを有している。 The step-down unit 25 has two winding transformers T21 and T22. The winding transformer T21 corresponds to the first winding transformer according to the present invention, and the winding transformer T22 corresponds to the second winding transformer according to the present invention. Winding transformers T21 and T22 have a primary coil and a secondary coil.
　なお、図の破線で示すキャパシタＣ１１は、巻線トランスＴ２１の１次コイルの巻線間浮遊容量である。また、キャパシタＣ１２は、巻線トランスＴ２２の１次コイルの巻線間浮遊容量である。 Note that a capacitor C11 indicated by a broken line in the figure is a stray capacitance between windings of the primary coil of the winding transformer T21. The capacitor C12 is a stray capacitance between windings of the primary coil of the winding transformer T22.
　巻線トランスＴ２１，Ｔ２２の１次コイル同士、２次コイル同士はそれぞれ直列に接続されている。直列に接続された１次コイルの接続点は、受電装置２０１の基準電位に接続されている。より詳しくは、巻線トランスＴ２１の１次コイルの一端はアクティブ電極２３に接続され、他端は送電装置１０１の基準電位に接続されている。巻線トランスＴ２２の１次コイルの一端はパッシブ電極２４に接続され、他端は送電装置１０１の基準電位に接続されている。また、巻線トランスＴ２１，Ｔ２２の２次コイルは直列接続されている。 The primary coils of the winding transformers T21 and T22 and the secondary coils are connected in series. A connection point of the primary coils connected in series is connected to the reference potential of the power receiving device 201. More specifically, one end of the primary coil of the winding transformer T21 is connected to the active electrode 23, and the other end is connected to the reference potential of the power transmission apparatus 101. One end of the primary coil of the winding transformer T22 is connected to the passive electrode 24, and the other end is connected to the reference potential of the power transmission apparatus 101. The secondary coils of the winding transformers T21 and T22 are connected in series.
　巻線トランスＴ２１，Ｔ２２を所定の条件を満たすように組み合わせ、降圧部２５を構成した場合、受電装置２０１の基準電位の変動を抑制できる。以下に、その条件について説明する。 When the winding transformers T21 and T22 are combined so as to satisfy a predetermined condition and the step-down unit 25 is configured, fluctuations in the reference potential of the power receiving device 201 can be suppressed. The conditions will be described below.
　巻線トランスＴ２１の１次コイルのインダクタンスをＬ１１、その１次コイルのキャパシタＣ１１のキャパシタンスをＣ１１で表す。また、巻線トランスＴ２２の１次コイルのインダクタンスをＬ１２、その１次コイルのキャパシタＣ１２のキャパシタンスをＣ１２で表す。ワイヤレス電力伝送システム１の電力伝送時の動作角周波数ω（＝２πｆ、ｆ：動作周波数）で表す。 The inductance of the primary coil of the winding transformer T21 is represented by L11, and the capacitance of the capacitor C11 of the primary coil is represented by C11. Further, the inductance of the primary coil of the winding transformer T22 is represented by L12, and the capacitance of the capacitor C12 of the primary coil is represented by C12. It is represented by an operating angular frequency ω (= 2πf, f: operating frequency) during power transmission of the wireless power transmission system 1.
　１／ωＣ１１＜ωＬ１１、１／ωＣ１２＜ωＬ１２である場合、受電装置２０１の基準電位の変動は、キャパシタンスＣ１１，Ｃ１２による影響が支配的となる。この場合、少なくともＣ１１≦Ｃ１２の条件（以下、条件（１）と言う。）を満たすように、巻線トランスＴ２１，Ｔ２２を選択する。 When 1 / ωC11 <ωL11 and 1 / ωC12 <ωL12, the influence of the capacitances C11 and C12 is dominant in the fluctuation of the reference potential of the power receiving apparatus 201. In this case, the winding transformers T21 and T22 are selected so as to satisfy at least the condition of C11 ≦ C12 (hereinafter referred to as condition (1)).
　１／ωＣ１１＞ωＬ１１、１／ωＣ１２＞ωＬ１２である場合、受電装置２０１の基準電位の変動は、インダクタンスＬ１１，Ｌ１２による影響が支配的となる。この場合、少なくともＬ１１≧Ｌ１２の条件（以下、条件（２）と言う。）を満たすように、巻線トランスＴ２１，Ｔ２２を選択する。 When 1 / ωC11> ωL11 and 1 / ωC12> ωL12, the influence of the inductances L11 and L12 is dominant in the fluctuation of the reference potential of the power receiving apparatus 201. In this case, the winding transformers T21 and T22 are selected so as to satisfy at least the condition of L11 ≧ L12 (hereinafter referred to as condition (2)).
　図２は、図１に示す受電装置２０１の等価回路を示す図である。降圧部２５は、等価的に図２に示す回路で表すことができる。図２では、直列接続された、巻線トランスＴ２１，Ｔ２２の１次コイルを一つの１次コイルｎ１で表し、直列接続された、巻線トランスＴ２１，Ｔ２２の２次コイルを一つの２次コイルｎ２で表している。キャパシタＣ１１，Ｃ１２は、図２で示すように、アクティブ電極２３及びパッシブ電極２４の間に直列に接続された構成で表せる。そして、キャパシタＣ１１，Ｃ１２の接続点は、受電装置２０１の基準電位に接続された構成となる。 FIG. 2 is a diagram showing an equivalent circuit of the power receiving device 201 shown in FIG. The step-down unit 25 can be equivalently represented by the circuit shown in FIG. In FIG. 2, the primary coil of the winding transformers T21 and T22 connected in series is represented by one primary coil n1, and the secondary coil of the winding transformers T21 and T22 connected in series is one secondary coil. This is represented by n2. The capacitors C11 and C12 can be represented by a configuration in which the capacitors C11 and C12 are connected in series between the active electrode 23 and the passive electrode 24, as shown in FIG. The connection point between the capacitors C11 and C12 is connected to the reference potential of the power receiving device 201.
　このワイヤレス電力伝送システム１において、前記の各条件（１）、（２）を満たすことで、受電装置２０１の基準電位の変動を抑制できる。そして、その結果、基準電位の変動による不具合、例えば、装置の誤作動等を防止できる。 In the wireless power transmission system 1, fluctuations in the reference potential of the power receiving device 201 can be suppressed by satisfying the above conditions (1) and (2). As a result, problems due to fluctuations in the reference potential, for example, malfunction of the device can be prevented.
　以下に、受電装置２０１の基準電位が安定する理由について説明する。 Hereinafter, the reason why the reference potential of the power receiving apparatus 201 is stabilized will be described.
　図３は、一部を省略したワイヤレス電力伝送システム１の等価回路図である。図３では、キャパシタＣ１ａ，Ｃ１ｐ，Ｃ１１，Ｃ１２及びキャパシタＣａ，Ｃｐから構成される回路を主に示し、他の回路、例えば、受電装置２０１のダイオードブリッジＤＢなどは負荷回路ＲＬとしてまとめている。また、図３に示すＴＧは、送電装置１０１の基準電位点であり、ＲＧは受電装置２０１の基準電位点である。この図３において、送電装置側基準電位点ＴＧと受電装置側基準電位点ＲＧとの電位差を抑えることにより、受電装置２０１の基準電位の安定化が可能となる。 FIG. 3 is an equivalent circuit diagram of the wireless power transmission system 1 with a part omitted. FIG. 3 mainly shows a circuit composed of capacitors C1a, C1p, C11, C12 and capacitors Ca, Cp, and other circuits, for example, the diode bridge DB of the power receiving device 201, are grouped as a load circuit RL. 3 is a reference potential point of the power transmitting apparatus 101, and RG is a reference potential point of the power receiving apparatus 201. In FIG. 3, the reference potential of the power receiving apparatus 201 can be stabilized by suppressing the potential difference between the power transmitting apparatus side reference potential point TG and the power receiving apparatus side reference potential point RG.
　図３において、キャパシタＣ１ａ，Ｃ１ｐのインピーダンスをＺ１，Ｚ２で表す。また、並列接続したキャパシタＣ１１及びインダクタＬ１１のインピーダンスをＺ３で表し、並列接続したキャパシタＣ１２及びインダクタＬ１２のインピーダンスをＺ４で表す。なお、説明を簡単にするため抵抗成分は無視する。この場合、インピーダンスＺ１，Ｚ２，Ｚ３，Ｚ４それぞれは以下の式（１）～（４）で表される（以下では、記号「//」は並列接続を表す）。 In FIG. 3, the impedances of the capacitors C1a and C1p are represented by Z1 and Z2. The impedance of the capacitor C11 and the inductor L11 connected in parallel is represented by Z3, and the impedance of the capacitor C12 and the inductor L12 connected in parallel is represented by Z4. For the sake of simplicity, the resistance component is ignored. In this case, the impedances Z1, Z2, Z3, and Z4 are expressed by the following equations (1) to (4) (in the following, the symbol “//” represents parallel connection).
　Ｚ１＝１／ｊωＣ１ａ…（１）
　Ｚ２＝１／ｊωＣ１ｐ…（２）
　Ｚ３＝（ｊωＬ１１）//（１／ｊωＣ１１）…（３）
　Ｚ４＝（ｊωＬ１２）//（１／ｊωＣ１２）…（４）
　ここで、電源回路側から視たブリッジ回路及び負荷回路側から視たブリッジ回路の両方の平衡条件から、
　Ｚ１／Ｚ２＝Ｚ３／Ｚ４＝（１／ｊωＣａａ）／（１／ｊωＣｐｐ）…（５）
　を満たしているとき、送電装置側基準電位点ＴＧと受電装置側基準電位点ＲＧとの電位差が０となる。 Z1 = 1 / jωC1a (1)
Z2 = 1 / jωC1p (2)
Z3 = (jωL11) // (1 / jωC11) (3)
Z4 = (jωL12) // (1 / jωC12) (4)
Here, from the equilibrium condition of both the bridge circuit viewed from the power supply circuit side and the bridge circuit viewed from the load circuit side,
Z1 / Z2 = Z3 / Z4 = (1 / jωCaa) / (1 / jωCpp) (5)
Is satisfied, the potential difference between the power transmission device side reference potential point TG and the power reception device side reference potential point RG is zero.
　前記式（１）～（５）から以下の式（６）が成り立つ。 The following formula (6) is established from the above formulas (1) to (5).
　C１ｐ／C１ａ＝（ωＬ１１－１／ωＣ１１）／（ωＬ１２－１／ωＣ１２）＝Ｃｐｐ／Ｃａａ…（６）
　よって、前記式（６）が成り立つように周波数に応じて各定数を定めれば送電装置側基準電位点ＴＧと受電装置側基準電位点ＲＧとの電位差が０となる。 C1p / C1a = (ωL11-1 / ωC11) / (ωL12-1 / ωC12) = Cpp / Caa (6)
Therefore, if each constant is determined according to the frequency so that the formula (6) is satisfied, the potential difference between the power transmission device side reference potential point TG and the power reception device side reference potential point RG becomes zero.
　ここで、Ｃａａ≦Ｃｐｐであるから、式（６）により、少なくともＣ１ａ≦Ｃ１ｐ、｜ωＬ１１－１／ωＣ１１｜≧｜ωＬ１２－１／ωＣ１２｜であることにより、不等号が逆の場合と比べて式（５）の各辺の差は小さい。このため、送電装置側基準電位点ＴＧと受電装置側基準電位点ＲＧとの電位差は小さい。ωＬ１１－１／ωＣ１１及びωＬ１２－１／ωＣ１２は、周波数によってインダクタンスＬ１１，Ｌ１２、又はキャパシタンスＣ１１，Ｃ１２の影響の大きさは変化する。 Here, since Caa ≦ Cpp, according to the equation (6), at least C1a ≦ C1p and | ωL11-1 / ωC11 | ≧ | ωL12-1 / ωC12 | The difference between the sides in (5) is small. For this reason, the potential difference between the power transmission device side reference potential point TG and the power reception device side reference potential point RG is small. In ωL11-1 / ωC11 and ωL12-1 / ωC12, the magnitude of the influence of the inductances L11 and L12 or the capacitances C11 and C12 varies depending on the frequency.
　以上より、キャパシタンスＣ１ａ，Ｃ１ｐの容量比と、キャパシタンスＣａａ，Ｃｐｐの容量比と、キャパシタンスＣ１１，Ｃ１２の容量比、又はインダクタンスＬ２ｐ，Ｌ２ａのインダクタンス比とを同じにすることで、受電装置２０１の基準電位が変動しないようにできる。 As described above, by making the capacitance ratio of the capacitances C1a and C1p, the capacitance ratio of the capacitances Caa and Cpp, the capacitance ratio of the capacitances C11 and C12, or the inductance ratio of the inductances L2p and L2a, the reference of the power receiving device 201 The potential can be prevented from fluctuating.
　条件（１）の場合、キャパシタンスＣ１１，Ｃ１２の影響が支配的となるため、Ｃ１１≦Ｃ１２が成り立つよう巻線トランスＴ２１，Ｔ２２の組み合わせることで、受電装置２０１の基準電位の変動を抑制できる。また、Ｃ１１／Ｃ１２＝Ｃａａ／Ｃｐｐであれば、より受電装置２０１の基準電位の変動を安定できる。 In the case of condition (1), the influence of the capacitances C11 and C12 becomes dominant. Therefore, by combining the winding transformers T21 and T22 so that C11 ≦ C12 is satisfied, fluctuations in the reference potential of the power receiving device 201 can be suppressed. Further, if C11 / C12 = Caa / Cpp, the fluctuation of the reference potential of the power receiving apparatus 201 can be further stabilized.
　条件（２）の場合、インダクタンスＬ１１，Ｌ１２の影響が支配的となるため、Ｌ１１≧Ｌ１２が成り立つよう巻線トランスＴ２１，Ｔ２２の組み合わせることで、受電装置２０１の基準電位の変動を抑制できる。また、Ｌ１２／Ｌ１１＝Ｃａａ／Ｃｐｐであれば、より受電装置２０１の基準電位の変動を安定できる。 In the condition (2), the influence of the inductances L11 and L12 becomes dominant. Therefore, by combining the winding transformers T21 and T22 so that L11 ≧ L12 is satisfied, fluctuations in the reference potential of the power receiving device 201 can be suppressed. Further, if L12 / L11 = Caa / Cpp, fluctuations in the reference potential of the power receiving apparatus 201 can be further stabilized.
　以上から、基準電位の変動を抑制するためには、受電装置２０１の製造時において、キャパシタＣａ，Ｃｐの容量比と同じになるように（又はそれに近づけるように）、巻線トランスＴ２１，Ｔ２２の組み合わせを決めればよい。 From the above, in order to suppress fluctuations in the reference potential, the winding transformers T21 and T22 are configured so as to be the same as (or close to) the capacitance ratio of the capacitors Ca and Cp when the power receiving apparatus 201 is manufactured. You just have to decide on a combination.
　巻線トランスＴ２１，Ｔ２２の組み合わせにより、基準電位の変動を抑制できるため、既存の巻線トランスを適宜選択すればよく、基準電位の変動を抑制のために巻線トランスを新たに設計する必要がない。また、キャパシタＣ１１，Ｃ１２の素子を設ける必要がなく、受電装置２０１の省スペース化が図れる。 Since the variation of the reference potential can be suppressed by the combination of the winding transformers T21 and T22, an existing winding transformer may be selected as appropriate, and it is necessary to newly design the winding transformer to suppress the variation of the reference potential. Absent. Further, it is not necessary to provide the elements of the capacitors C11 and C12, and the power receiving device 201 can be saved in space.
　本実施形態に係る降圧部２５は、上述の構成に限定されない。図４Ａ及び図４Ｂは、降圧部２５の別の例を示す図である。 The step-down unit 25 according to the present embodiment is not limited to the above-described configuration. 4A and 4B are diagrams illustrating another example of the step-down unit 25. FIG.
　本実施形態では、降圧部２５の巻線トランスＴ２１，Ｔ２２の２次コイルは直列に接続されているが、図４Ａに示すように、２次コイルは並列に接続されてもよい。また、本実施形態に係る降圧部２５は、高電圧を取り扱うことができる絶縁型巻線トランスとしているが、降圧部２５は、図４Ｂに示すように、巻線トランスＴ２１，Ｔ２２は非絶縁型巻線トランスであってもよい。 In the present embodiment, the secondary coils of the winding transformers T21 and T22 of the step-down unit 25 are connected in series, but the secondary coils may be connected in parallel as shown in FIG. 4A. In addition, the step-down unit 25 according to the present embodiment is an insulated winding transformer that can handle a high voltage, but the step-down unit 25 has non-insulated winding transformers T21 and T22 as shown in FIG. 4B. A winding transformer may be used.
　また、本実施形態に係る降圧部２５において、巻線トランスＴ２１，Ｔ２２の１次コイルは直列に接続され、その接続点は、受電装置２０１の基準電位に接続されているが、基準電位に接続しなくてもよい。 In the step-down unit 25 according to the present embodiment, the primary coils of the winding transformers T21 and T22 are connected in series, and the connection point is connected to the reference potential of the power receiving apparatus 201, but is connected to the reference potential. You don't have to.
　図５は、降圧部２５が有する巻線トランスＴ２１，Ｔ２２の１次コイルの接続点を、グランド接続しない場合の例を示す図である。 FIG. 5 is a diagram illustrating an example in which the connection point of the primary coil of the winding transformers T21 and T22 included in the step-down unit 25 is not connected to the ground.
　この例では、巻線トランスＴ２１，Ｔ２２の１次側が、受電装置２０１の基準電位に対して絶縁している。このため、インダクタンスＬ１１，Ｌ１２、及びキャパシタンスＣ１１，Ｃ１２は、受電装置２０１の基準電位の変動には寄与しない。したがって、この例では、受電装置２０１の基準電位の変動を抑制するためには、図示する、巻線トランスＴ２１の１次－２次間の静電容量Ｃ１３と、巻線トランスＴ２２の１次－２次間の静電容量Ｃ１４との関係が、Ｃ１３≦Ｃ１４を満たすように、巻線トランスＴ２１，Ｔ２２を組み合わせる必要がある。 In this example, the primary sides of the winding transformers T21 and T22 are insulated from the reference potential of the power receiving device 201. For this reason, the inductances L11 and L12 and the capacitances C11 and C12 do not contribute to fluctuations in the reference potential of the power receiving apparatus 201. Therefore, in this example, in order to suppress the fluctuation of the reference potential of the power receiving apparatus 201, the primary-secondary capacitance C13 of the winding transformer T21 and the primary-order of the winding transformer T22 are illustrated. The winding transformers T21 and T22 need to be combined so that the relationship between the secondary capacitance C14 satisfies C13 ≦ C14.
　巻線トランスＴ２１，Ｔ２２の１次コイルに印加される電圧と比較すると、２次コイルに発生する電圧は十分低い。２次コイルは基準電位に接続しているため、２次コイル全体を基準電位とした回路と等価的に見ることができる。この場合、静電容量Ｃ１３と静電容量Ｃ１４との比を、キャパシタンスＣａａ，Ｃｐｐの比に合わせる（近づける）。すなわち、Ｃａａ≦Ｃｐｐの関係から、Ｃ１３≦Ｃ１４の条件が導くことができる。Ｃ１３≦Ｃ１４の条件を満たすように、巻線トランスＴ２１，Ｔ２２の組み合わせることで、受電装置２０１の基準電位の変動を抑制できる。 Compared with the voltage applied to the primary coil of the winding transformers T21 and T22, the voltage generated in the secondary coil is sufficiently low. Since the secondary coil is connected to the reference potential, it can be equivalently viewed as a circuit having the entire secondary coil as the reference potential. In this case, the ratio between the capacitance C13 and the capacitance C14 is adjusted to (close to) the ratio between the capacitances Caa and Cpp. That is, the condition of C13 ≦ C14 can be derived from the relationship of Caa ≦ Cpp. By combining the winding transformers T21 and T22 so as to satisfy the condition of C13 ≦ C14, fluctuations in the reference potential of the power receiving device 201 can be suppressed.
　図６は、静電容量Ｃ１３，Ｃ１４を説明するための図である。図に示すように、巻線トランスＴ２１の１次コイルと２次コイルとの間には、線間容量Ｃ０１が生じる。静電容量Ｃ１３は、この線間容量Ｃ０１を総合して等価的に表したものである。同様に、巻線トランスＴ２２の１次コイルと２次コイルとの間には、線間容量Ｃ０２が生じる。静電容量Ｃ１４は、この線間容量Ｃ０２を総合して等価的に表したものである。 FIG. 6 is a diagram for explaining the capacitances C13 and C14. As shown in the figure, a line capacitance C01 is generated between the primary coil and the secondary coil of the winding transformer T21. The capacitance C13 is an equivalent representation of the inter-line capacitance C01. Similarly, a line capacitance C02 is generated between the primary coil and the secondary coil of the winding transformer T22. The capacitance C14 is an equivalent representation of the inter-line capacitance C02.
　なお、本実施形態では、送電装置１０１は昇圧トランス１２を備え、受電装置２０１は降圧部２５を備えた場合について説明したが、各装置１０１，２０１が備えるトランスは、昇圧及び降圧に限定されない。例えば、送電装置１０１及び受電装置２０１は変圧しない絶縁型トランスを備えていてもよいし、送電装置１０１は降圧トランスを備え、受電装置２０１は昇圧トランスを備えていてもよい。そして、受電装置２０１が昇圧トランスを備える場合、本実施形態と同様に、昇圧トランスが有するキャパシタ成分であるキャパシタＣ１１，Ｃ１２を利用して、昇圧トランスの巻線トランスを適宜組み合わせ、受電装置２０１の基準電位の変動を抑制するようにしてもよい。 In the present embodiment, the power transmission device 101 includes the step-up transformer 12 and the power reception device 201 includes the step-down unit 25. However, the transformers included in the devices 101 and 201 are not limited to step-up and step-down. For example, the power transmission device 101 and the power reception device 201 may include an insulating transformer that does not transform, the power transmission device 101 may include a step-down transformer, and the power reception device 201 may include a step-up transformer. When the power receiving device 201 includes a step-up transformer, the winding transformer of the step-up transformer is appropriately combined using the capacitors C11 and C12 that are capacitor components included in the step-up transformer, as in the present embodiment, and You may make it suppress the fluctuation | variation of a reference potential.
（実施形態２）
　本実施形態では、ワイヤレス電力伝送システムの送電装置が有する昇圧トランスの構成が、実施形態１と相違する。受電装置は実施形態１と同様である。 (Embodiment 2)
In the present embodiment, the configuration of the step-up transformer included in the power transmission device of the wireless power transmission system is different from that in the first embodiment. The power receiving apparatus is the same as that in the first embodiment.
　図７は、実施形態２に係る送電装置１０２の回路図である。送電装置１０２は、電源回路１１、昇圧部１５、アクティブ電極１３及びパッシブ電極１４を備えている。 FIG. 7 is a circuit diagram of the power transmission apparatus 102 according to the second embodiment. The power transmission device 102 includes a power supply circuit 11, a booster 15, an active electrode 13, and a passive electrode 14.
　昇圧部１５は、二つの巻線トランスＴ１１，Ｔ１２を有している。昇圧部１５は、本発明に係る第２トランスに相当する。巻線トランスＴ１１は、本発明に係る第３巻線トランスに相当し、巻線トランスＴ１２は、本発明に係る第４巻線トランスに相当する。巻線トランスＴ１１，Ｔ１２は、１次コイルと２次コイルとを有している。 The booster 15 has two winding transformers T11 and T12. The booster 15 corresponds to a second transformer according to the present invention. The winding transformer T11 corresponds to a third winding transformer according to the present invention, and the winding transformer T12 corresponds to a fourth winding transformer according to the present invention. Winding transformers T11 and T12 have a primary coil and a secondary coil.
　なお、図７の破線で示すキャパシタＣ２１は、巻線トランスＴ１１の２次コイルの巻線間浮遊容量である。また、キャパシタＣ２２は、巻線トランスＴ１２の２次コイルの巻線間浮遊容量である。 Note that a capacitor C21 indicated by a broken line in FIG. 7 is a stray capacitance between windings of the secondary coil of the winding transformer T11. The capacitor C22 is a stray capacitance between windings of the secondary coil of the winding transformer T12.
　巻線トランスＴ１１，Ｔ１２の１次コイル同士、２次コイル同士はそれぞれ直列に接続されている。直列に接続された２次コイルの接続点は、送電装置１０２の基準電位に接続されている。より詳しくは、巻線トランスＴ１１の２次コイルは、一端がアクティブ電極１３に接続され、他端が送電装置１０２の基準電位に接続されている。巻線トランスＴ１２の２次コイルは、一端がパッシブ電極１４に接続され、他端が送電装置１０２の基準電位に接続されている。また、巻線トランスＴ１１，Ｔ１２の１次コイルは直列接続されている。 The primary coils and secondary coils of the winding transformers T11 and T12 are connected in series. The connection point of the secondary coils connected in series is connected to the reference potential of the power transmission device 102. More specifically, one end of the secondary coil of the winding transformer T <b> 11 is connected to the active electrode 13, and the other end is connected to the reference potential of the power transmission device 102. One end of the secondary coil of the winding transformer T <b> 12 is connected to the passive electrode 14, and the other end is connected to the reference potential of the power transmission device 102. The primary coils of the winding transformers T11 and T12 are connected in series.
　巻線トランスＴ１１，Ｔ１２を所定の条件を満たすように組み合わせ、昇圧部１５を構成した場合、送電装置１０２から電力伝送される受電装置の基準電位の変動を抑制できる。以下に、その条件について説明する。 When the winding transformers T <b> 11 and T <b> 12 are combined so as to satisfy a predetermined condition and the boosting unit 15 is configured, fluctuations in the reference potential of the power receiving device to which power is transmitted from the power transmitting device 102 can be suppressed. The conditions will be described below.
　巻線トランスＴ１１の２次コイルのインダクタンスをＬ２１、その１次コイルのキャパシタＣ２１のキャパシタンスをＣ２１で表す。また、巻線トランスＴ１２の２次コイルのインダクタンスをＬ２２、その１次コイルのキャパシタＣ２２のキャパシタンスをＣ２２で表す。ワイヤレス電力伝送システム１の電力伝送時の動作角周波数をωで表す。 The inductance of the secondary coil of the winding transformer T11 is represented by L21, and the capacitance of the capacitor C21 of the primary coil is represented by C21. Further, the inductance of the secondary coil of the winding transformer T12 is represented by L22, and the capacitance of the capacitor C22 of the primary coil is represented by C22. The operating angular frequency during power transmission of the wireless power transmission system 1 is represented by ω.
　１／ωＣ２１＜ωＬ２１、１／ωＣ２２＜ωＬ２２である場合、受電装置の基準電位の変動は、キャパシタンスＣ２１，Ｃ２２による影響が支配的となる。この場合、少なくともＣ２１≦Ｃ２２の条件（以下、条件（３）と言う。）を満たすように、巻線トランスＴ１１，Ｔ１２を選択する。これにより、受電装置の基準電位の変動を抑制できる。また、Ｃ２１／Ｃ２２＝Ｃａａ／Ｃｐｐであれば、より受電装置の基準電位の変動を安定できる。 When 1 / ωC21 <ωL21 and 1 / ωC22 <ωL22, the influence of the capacitances C21 and C22 is dominant in the fluctuation of the reference potential of the power receiving apparatus. In this case, the winding transformers T11 and T12 are selected so as to satisfy at least the condition of C21 ≦ C22 (hereinafter referred to as condition (3)). Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed. Further, if C21 / C22 = Caa / Cpp, fluctuations in the reference potential of the power receiving apparatus can be further stabilized.
　１／ωＣ２１＞ωＬ２１、１／ωＣ２２＞ωＬ２２である場合、受電装置の基準電位の変動は、インダクタンスＬ２１，Ｌ２２による影響が支配的となる。この場合、少なくともＬ２１≧Ｌ２２の条件（以下、条件（４）と言う。）を満たすように、巻線トランスＴ１１，Ｔ１２を選択する。これにより、受電装置の基準電位の変動を抑制できる。また、Ｌ２２／Ｌ２１＝Ｃａａ／Ｃｐｐであれば、より受電装置の基準電位の変動を安定できる。 When 1 / ωC21> ωL21 and 1 / ωC22> ωL22, the influence of the inductances L21 and L22 is dominant in the fluctuation of the reference potential of the power receiving apparatus. In this case, the winding transformers T11 and T12 are selected so as to satisfy at least the condition of L21 ≧ L22 (hereinafter referred to as condition (4)). Thereby, the fluctuation | variation of the reference electric potential of a receiving device can be suppressed. Further, if L22 / L21 = Caa / Cpp, the fluctuation of the reference potential of the power receiving apparatus can be more stabilized.
　なお、送電装置１０１の昇圧部、及び受電装置２０１の降圧部それぞれに巻線トランスを設ける本実施形態において、昇圧部の巻線トランスＴ１１と、降圧部の巻線トランスＴ２１とが同じ巻線トランスを用い、昇圧部の巻線トランスＴ１２と、降圧部の巻線トランスＴ２２とが同じ巻線トランスを用いることができる。この場合、送電装置１０１と受電装置２０１とで容量比を略同じにすることができ、受電装置２０１の基準電位をより安定化できる。 In this embodiment in which a winding transformer is provided in each of the step-up unit of the power transmission device 101 and the step-down unit of the power receiving device 201, the winding transformer T11 of the step-up unit and the winding transformer T21 of the step-down unit are the same winding transformer. The winding transformer T12 of the step-up unit and the winding transformer T22 of the step-down unit can use the same winding transformer. In this case, the power transmission device 101 and the power receiving device 201 can have substantially the same capacity ratio, and the reference potential of the power receiving device 201 can be further stabilized.
　また、実施形態１の図５で説明した場合と同様に、昇圧部１５が有する巻線トランスＴ１１，Ｔ１２の２次コイルの接続点は、グランド接続されていなくてもよい。この場合、巻線トランスＴ１１，Ｔ１２の２次側が、送電装置１０２の基準電位に対して絶縁している。このため、インダクタンスＬ２１，Ｌ２２、及びキャパシタンスＣ２１，Ｃ２２は、送電装置１０２の基準電位の変動には寄与しない。したがって、この例では、送電装置１０２の基準電位の変動を抑制するためには、巻線トランスＴ１１の１次－２次間の静電容量Ｃ２３と、巻線トランスＴ１２の１次－２次間の静電容量Ｃ２４との関係が、Ｃ２３≦Ｃ２４を満たすように、巻線トランスＴ１１，Ｔ１２を組み合わせる必要がある。 Further, similarly to the case described with reference to FIG. 5 of the first embodiment, the connection point of the secondary coils of the winding transformers T11 and T12 included in the boosting unit 15 may not be connected to the ground. In this case, the secondary sides of the winding transformers T11 and T12 are insulated from the reference potential of the power transmission device 102. For this reason, inductance L21, L22 and capacitance C21, C22 do not contribute to the fluctuation | variation of the reference electric potential of the power transmission apparatus 102. FIG. Therefore, in this example, in order to suppress the fluctuation of the reference potential of the power transmitting apparatus 102, the primary-secondary capacitance C23 of the winding transformer T11 and the primary-secondary of the winding transformer T12. It is necessary to combine the winding transformers T11 and T12 so that the relationship with the electrostatic capacity C24 satisfies C23 ≦ C24.
（実施形態３）
　図８は、実施形態３に係るワイヤレス電力伝送システムの受電装置の回路図である。本実施形態に係る受電装置２０２は、降圧部２６の構成が実施形態１と相違する。ワイヤレス電力伝送システムの送電装置は、実施形態１と同様である。 (Embodiment 3)
FIG. 8 is a circuit diagram of a power receiving device of the wireless power transmission system according to the third embodiment. The power receiving device 202 according to the present embodiment is different from the first embodiment in the configuration of the step-down unit 26. The power transmission device of the wireless power transmission system is the same as that of the first embodiment.
　降圧部２６は、ローゼン型の圧電トランス２６１，２６２を備えている。圧電トランス２６１は、本発明に係る第１圧電トランスに相当し、圧電トランス２６２は、本発明に係る第２圧電トランスに相当する。圧電トランス２６１は、λ共振モードで振動し、圧電トランス２６２は、（λ／２）共振モードで振動する。 The step-down unit 26 includes Rosen-type piezoelectric transformers 261 and 262. The piezoelectric transformer 261 corresponds to the first piezoelectric transformer according to the present invention, and the piezoelectric transformer 262 corresponds to the second piezoelectric transformer according to the present invention. The piezoelectric transformer 261 vibrates in the λ resonance mode, and the piezoelectric transformer 262 vibrates in the (λ / 2) resonance mode.
　圧電トランス２６１，２６２は、第１電極Ｅ１１，Ｅ２１、第２電極Ｅ１２，Ｅ２２、及び第３電極Ｅ１３，Ｅ２３を有している。圧電トランス２６１の第１電極Ｅ１１は、アクティブ電極２３に接続されている。圧電トランス２６２の第１電極Ｅ２１は、パッシブ電極２４に接続されている。圧電トランス２６１，２６２の第２電極Ｅ１２，Ｅ２２は、受電装置２０２の基準電位に接続されている。圧電トランス２６１，２６２の第３電極Ｅ１３，Ｅ２３は、共振用のインダクタＬ２、整流用のダイオードブリッジＤＢ、平滑用のインダクタＬ１及びキャパシタＣｏが接続されている。 The piezoelectric transformers 261 and 262 have first electrodes E11 and E21, second electrodes E12 and E22, and third electrodes E13 and E23. The first electrode E11 of the piezoelectric transformer 261 is connected to the active electrode 23. The first electrode E <b> 21 of the piezoelectric transformer 262 is connected to the passive electrode 24. The second electrodes E12 and E22 of the piezoelectric transformers 261 and 262 are connected to the reference potential of the power receiving device 202. The third electrodes E13 and E23 of the piezoelectric transformers 261 and 262 are connected to a resonance inductor L2, a rectification diode bridge DB, a smoothing inductor L1, and a capacitor Co.
　この降圧部２６において、圧電トランス２６１，２６２は、第１電極Ｅ１１，Ｅ２１に電圧が印加されると、逆圧電効果により、駆動信号に応じた周期で応力が生じ、その機械的歪みにより降圧した電圧を第３電極Ｅ１３，Ｅ２３から出力する。この圧電トランス２６１，２６２は、第１電極Ｅ１１，Ｅ２１と、第３電極Ｅ１３，Ｅ２３とは絶縁性を保っている。このため、受電装置２０２の降圧部において、入出力間で電気的に絶縁することで、負荷回路ＲＬ側への高圧部（アクティブ電極１３，２３の結合）によるノイズの影響を抑制できる。 In the step-down unit 26, when a voltage is applied to the first electrodes E11 and E21, the piezoelectric transformers 261 and 262 generate stress at a period corresponding to the drive signal due to the inverse piezoelectric effect, and the voltage is lowered due to the mechanical distortion. The voltage is output from the third electrodes E13 and E23. In the piezoelectric transformers 261 and 262, the first electrodes E11 and E21 and the third electrodes E13 and E23 maintain insulation. For this reason, in the step-down unit of the power receiving apparatus 202, the influence of noise due to the high-voltage unit (the coupling of the active electrodes 13 and 23) to the load circuit RL side can be suppressed by electrically insulating the input and output.
　図８の破線で示すキャパシタＣ１５は、圧電トランス２６１の第１電極Ｅ１１と第２電極Ｅ１２との間に生じるキャパシタンス成分であり、キャパシタＣ１６は、圧電トランス２６２の第１電極Ｅ２１と第２電極Ｅ２２との間に生じるキャパシタンス成分である。また、第３電極Ｅ１３，Ｅ２３は、受電装置２０２の基準電位に接続されている。換言すれば、キャパシタＣ１５は、アクティブ電極２３と基準電位との間に生じる容量、キャパシタＣ１６は、パッシブ電極２４と基準電位との間に生じる容量である。 A capacitor C15 indicated by a broken line in FIG. 8 is a capacitance component generated between the first electrode E11 and the second electrode E12 of the piezoelectric transformer 261, and the capacitor C16 is a first electrode E21 and a second electrode E22 of the piezoelectric transformer 262. Is a capacitance component generated between The third electrodes E13 and E23 are connected to the reference potential of the power receiving device 202. In other words, the capacitor C15 is a capacitance generated between the active electrode 23 and the reference potential, and the capacitor C16 is a capacitance generated between the passive electrode 24 and the reference potential.
　また、圧電トランス２６１はλ共振モードで振動し、圧電トランス２６２は（λ／２）共振モードで振動することから、第１電極Ｅ１１と第２電極Ｅ１２との距離は、第１電極Ｅ２１と第２電極Ｅ２２との距離より長い。すなわち、キャパシタＣ１５のキャパシタンス（以下、Ｃ１５で表す）は、キャパシタＣ１６（以下、Ｃ１６で表す）のキャパシタンスよりも小さい。このため、Ｃ１５＜Ｃ１６の関係が成り立つ。なお、圧電トランス２６１，２６２に同じ圧電トランスを用いた場合には、Ｃ１５＝１６の関係が成り立つ。 Further, since the piezoelectric transformer 261 vibrates in the λ resonance mode and the piezoelectric transformer 262 vibrates in the (λ / 2) resonance mode, the distance between the first electrode E11 and the second electrode E12 is the first electrode E21 and the first electrode E21. It is longer than the distance to the two electrodes E22. That is, the capacitance of the capacitor C15 (hereinafter represented by C15) is smaller than the capacitance of the capacitor C16 (hereinafter represented by C16). For this reason, the relationship of C15 <C16 is established. When the same piezoelectric transformer is used for the piezoelectric transformers 261 and 262, the relationship of C15 = 16 is established.
　以上より、キャパシタＣ１５，Ｃ１６は、実施形態１と同様に、アクティブ電極２３及びパッシブ電極２４の間に直列に接続され、キャパシタＣ１５，Ｃ１６の接続点が基準電位に接続された回路構成と同視できる。この場合、キャパシタＣ１５，Ｃ１６の影響が支配的となるため、Ｃ１５≦Ｃ１６が成り立つよう、圧電トランス２６１，２６２を組み合わせることで、受電装置２０２の基準電位の変動を抑制できる。また、Ｃ１５／Ｃ１６＝Ｃａａ／Ｃｐｐであれば、より受電装置２０２の基準電位の変動を安定できる。 As described above, the capacitors C15 and C16 can be regarded as a circuit configuration in which the connection points of the capacitors C15 and C16 are connected to the reference potential in series between the active electrode 23 and the passive electrode 24 as in the first embodiment. . In this case, since the influence of the capacitors C15 and C16 becomes dominant, fluctuations in the reference potential of the power receiving apparatus 202 can be suppressed by combining the piezoelectric transformers 261 and 262 so that C15 ≦ C16 holds. Further, if C15 / C16 = Caa / Cpp, fluctuations in the reference potential of the power receiving apparatus 202 can be further stabilized.
　また、受電装置２０２が例えば携帯電話機等、小型化、薄型化が望まれる装置である場合には、圧電トランス２６１，２６２により降圧部２６を構成することで、受電装置２０２の小型化、薄型化を実現できる。 Further, when the power receiving device 202 is a device that is desired to be reduced in size and thickness, such as a mobile phone, the voltage step-down unit 26 is configured by the piezoelectric transformers 261 and 262 so that the power receiving device 202 is reduced in size and thickness. Can be realized.
（実施形態４）
　本実施形態では、ワイヤレス電力伝送システムの送電装置が有する昇圧トランスの構成が、実施形態３と相違する。受電装置は、実施形態１又は実施形態３に係る受電装置と同じである。 (Embodiment 4)
In the present embodiment, the configuration of the step-up transformer included in the power transmission device of the wireless power transmission system is different from that in the third embodiment. The power receiving device is the same as the power receiving device according to the first or third embodiment.
　図９は、実施形態４に係る送電装置１０３の回路図である。送電装置１０３は、電源回路１１、昇圧部１６、アクティブ電極１３及びパッシブ電極１４を備えている。 FIG. 9 is a circuit diagram of the power transmission device 103 according to the fourth embodiment. The power transmission device 103 includes a power supply circuit 11, a booster 16, an active electrode 13, and a passive electrode 14.
　昇圧部１６は、二つのローゼン型の圧電トランス１６１，１６２を有している。圧電トランス１６１は、本発明に係る第３圧電トランスに相当し、圧電トランス１６２は、本発明に係る第４圧電トランスに相当する。圧電トランス１６１は、λ共振モードで振動し、圧電トランス１６２は、（λ／２）共振モードで振動する。 The step-up unit 16 has two Rosen-type piezoelectric transformers 161 and 162. The piezoelectric transformer 161 corresponds to the third piezoelectric transformer according to the present invention, and the piezoelectric transformer 162 corresponds to the fourth piezoelectric transformer according to the present invention. The piezoelectric transformer 161 vibrates in the λ resonance mode, and the piezoelectric transformer 162 vibrates in the (λ / 2) resonance mode.
　圧電トランス１６１，１６２は、第１電極Ｅ３１，Ｅ４１、第２電極Ｅ３２，Ｅ４２、及び第３電極Ｅ３３，Ｅ４３を有している。圧電トランス１６１の第１電極Ｅ３１は、アクティブ電極１３に接続されている。圧電トランス１６２の第１電極Ｅ４１は、パッシブ電極１４に接続されている。圧電トランス１６１，１６２の第２電極Ｅ３２，Ｅ４２は、送電装置１０３の基準電位に接続されている。圧電トランス１６１，１６２の第３電極Ｅ３３，Ｅ４３は、電源回路１１に接続されている。 The piezoelectric transformers 161 and 162 have first electrodes E31 and E41, second electrodes E32 and E42, and third electrodes E33 and E43. The first electrode E31 of the piezoelectric transformer 161 is connected to the active electrode 13. The first electrode E41 of the piezoelectric transformer 162 is connected to the passive electrode 14. The second electrodes E32 and E42 of the piezoelectric transformers 161 and 162 are connected to the reference potential of the power transmission device 103. The third electrodes E33 and E43 of the piezoelectric transformers 161 and 162 are connected to the power supply circuit 11.
　このように構成される昇圧部１６において、圧電トランス１６１，１６２は、第２電極Ｅ３２，Ｅ４２、及び第３電極Ｅ３３，Ｅ４３に、電源回路１１から交流電圧が印加されると、逆圧電効果により、駆動信号に応じた周期で応力が生じ、その機械的歪みにより昇圧した電圧を第１電極Ｅ３１，Ｅ４１から出力する。そして、アクティブ電極１３及びパッシブ電極１４には、圧電トランス１６１，１６２により昇圧された電圧が印加される。 In the boosting unit 16 configured as described above, when the AC voltage is applied to the piezoelectric transformers 161 and 162 from the power supply circuit 11 to the second electrodes E32 and E42 and the third electrodes E33 and E43, the piezoelectric transformers 161 and 162 have an inverse piezoelectric effect. Stress is generated at a period corresponding to the drive signal, and a voltage boosted by the mechanical strain is output from the first electrodes E31 and E41. The voltage boosted by the piezoelectric transformers 161 and 162 is applied to the active electrode 13 and the passive electrode 14.
　図９の破線で示すキャパシタＣ２５は、圧電トランス１６１の第１電極Ｅ３１と第２電極Ｅ３２との間に生じるキャパシタンス成分であり、キャパシタＣ２６は、圧電トランス１６２の第１電極Ｅ４１と第２電極Ｅ４２との間に生じるキャパシタンス成分である。また、第３電極Ｅ３３，Ｅ４３は、送電装置１０３の基準電位に接続されている。換言すれば、キャパシタＣ２５は、アクティブ電極１３と基準電位との間に生じる容量、キャパシタＣ２６は、パッシブ電極１４と基準電位との間に生じる容量である。 A capacitor C25 indicated by a broken line in FIG. 9 is a capacitance component generated between the first electrode E31 and the second electrode E32 of the piezoelectric transformer 161, and the capacitor C26 is a first electrode E41 and a second electrode E42 of the piezoelectric transformer 162. Is a capacitance component generated between The third electrodes E33 and E43 are connected to the reference potential of the power transmission device 103. In other words, the capacitor C25 is a capacitance generated between the active electrode 13 and the reference potential, and the capacitor C26 is a capacitance generated between the passive electrode 14 and the reference potential.
　また、圧電トランス１６１はλ共振モードで振動し、圧電トランス１６２は（λ／２）共振モードで振動することから、圧電トランス１６１の第１電極Ｅ３１と第２電極Ｅ３２との距離は、圧電トランス１６２の第１電極Ｅ４１と第２電極Ｅ４２との距離より長い。すなわち、キャパシタＣ２５のキャパシタンス（以下、Ｃ２５で表す）は、キャパシタＣ２６のキャパシタンス（以下、Ｃ２６で表す）よりも小さい。このため、Ｃ２５＜Ｃ２６の関係が成り立つ。なお、圧電トランス１６１，１６２に同じ圧電トランスを用いた場合には、Ｃ２５＝Ｃ２６の関係が成り立つ。 Also, since the piezoelectric transformer 161 vibrates in the λ resonance mode and the piezoelectric transformer 162 vibrates in the (λ / 2) resonance mode, the distance between the first electrode E31 and the second electrode E32 of the piezoelectric transformer 161 is the piezoelectric transformer. 162 is longer than the distance between the first electrode E41 and the second electrode E42. That is, the capacitance of the capacitor C25 (hereinafter represented by C25) is smaller than the capacitance of the capacitor C26 (hereinafter represented by C26). For this reason, the relationship of C25 <C26 is established. When the same piezoelectric transformer is used for the piezoelectric transformers 161 and 162, the relationship of C25 = C26 is established.
　以上より、キャパシタＣ２５，Ｃ２６は、実施形態２と同様に、アクティブ電極１３及びパッシブ電極１４の間に直列に接続され、キャパシタＣ２５，Ｃ２６の接続点が基準電位に接続された回路構成と同視できる。この場合、キャパシタＣ２５，Ｃ２６の影響が支配的となるため、Ｃ２５≦Ｃ２６が成り立つよう、圧電トランス１６１，１６２を組み合わせることで、受電装置の基準電位の変動を抑制できる。また、Ｃ２５／Ｃ２６＝Ｃａａ／Ｃｐｐであれば、より受電装置の基準電位の変動を安定できる。 As described above, the capacitors C25 and C26 are connected in series between the active electrode 13 and the passive electrode 14 as in the second embodiment, and can be regarded as a circuit configuration in which the connection point of the capacitors C25 and C26 is connected to the reference potential. . In this case, since the influence of the capacitors C25 and C26 becomes dominant, the piezoelectric transformers 161 and 162 are combined so that C25 ≦ C26 can be satisfied, so that fluctuations in the reference potential of the power receiving device can be suppressed. Further, if C25 / C26 = Caa / Cpp, fluctuations in the reference potential of the power receiving apparatus can be further stabilized.
　また、送電装置１０３に圧電トランス１６１，１６２を適用することで、送電装置１０３の小型化、薄型化を実現できる。 Further, by applying the piezoelectric transformers 161 and 162 to the power transmission device 103, the power transmission device 103 can be reduced in size and thickness.
　なお、送電装置の昇圧部、及び受電装置の降圧部それぞれに圧電トランスを設けた場合、実施形態３の降圧部２６の圧電トランス２６１と、本実施形態の昇圧部１６の圧電トランス１６１とが同じ圧電トランスであり、実施形態３の降圧部２６の圧電トランス２６２と、本実施形態の昇圧部１６の圧電トランス１６２とが同じ圧電トランスであることが好ましい。この場合、送電装置と受電装置とで容量比を略同じにすることができ、受電装置の基準電位をより安定化できる。 In addition, when a piezoelectric transformer is provided in each of the step-up unit of the power transmission device and the step-down unit of the power receiving device, the piezoelectric transformer 261 of the step-down unit 26 of the third embodiment and the piezoelectric transformer 161 of the step-up unit 16 of the present embodiment are the same. It is a piezoelectric transformer, and it is preferable that the piezoelectric transformer 262 of the step-down unit 26 of the third embodiment and the piezoelectric transformer 162 of the step-up unit 16 of the present embodiment are the same piezoelectric transformer. In this case, the capacity ratio can be made substantially the same between the power transmission device and the power reception device, and the reference potential of the power reception device can be further stabilized.
（実施形態５）
　図１０は、実施形態５に係るワイヤレス電力伝送システム５の回路図である。 (Embodiment 5)
FIG. 10 is a circuit diagram of the wireless power transmission system 5 according to the fifth embodiment.
　ワイヤレス電力伝送システム５が備える送電装置１０５及び受電装置２０５は、それぞれの基準電位に接続された基準電位電極１０５Ａ，２０５Ａを備えている。送電装置１０５に受電装置２０５を載置した場合、基準電位電極１０５Ａ，２０５Ａは対向し、キャパシタＣｇを形成する。したがって、受電装置２０５の基準電位は、形成されたキャパシタＣｇを介して、送電装置１０５の基準電位と接続される。受電装置２０５の基準電位を、キャパシタＣｇを介して送電装置１０５の基準電位に接続することで、受電装置２０５の基準電位の安定化が図れる。 The power transmission device 105 and the power reception device 205 included in the wireless power transmission system 5 include reference potential electrodes 105A and 205A connected to respective reference potentials. When the power receiving device 205 is mounted on the power transmitting device 105, the reference potential electrodes 105A and 205A face each other to form a capacitor Cg. Therefore, the reference potential of the power receiving device 205 is connected to the reference potential of the power transmission device 105 via the formed capacitor Cg. By connecting the reference potential of the power receiving apparatus 205 to the reference potential of the power transmitting apparatus 105 via the capacitor Cg, the reference potential of the power receiving apparatus 205 can be stabilized.
　送電装置１０５は、電源回路１１からの交流電圧を昇圧し、アクティブ電極１３及びパッシブ電極１４へ印加する昇圧部１７を備えている。昇圧部１７は、二つの圧電トランス１７１，１７２を有している。圧電トランス１７１は、本発明に係る「第３圧電トランス」に相当し、圧電トランス１７１は、本発明に係る「第４圧電トランス」に相当する。 The power transmission device 105 includes a boosting unit 17 that boosts an AC voltage from the power supply circuit 11 and applies the boosted voltage to the active electrode 13 and the passive electrode 14. The booster unit 17 has two piezoelectric transformers 171 and 172. The piezoelectric transformer 171 corresponds to a “third piezoelectric transformer” according to the present invention, and the piezoelectric transformer 171 corresponds to a “fourth piezoelectric transformer” according to the present invention.
　圧電トランス１７１は、第１電極Ｅ５１、第２電極Ｅ５２、第３電極Ｅ５３及び第４電極Ｅ５４を備えている。圧電トランス１７２は、第１電極Ｅ６１、第２電極Ｅ６２、第３電極Ｅ６３及び第４電極Ｅ６４を備えている。第１電極Ｅ５１，Ｅ６１は、本発明に係る「第１電圧入力電極」に相当する。第２電極Ｅ５２，Ｅ６２は、本発明に係る「第２電圧入力電極」に相当する。第３電極Ｅ５３，Ｅ６３は、本発明に係る「第１電圧出力電極」に相当する。第４電極Ｅ５４，Ｅ６４は、本発明に係る「第２電圧出力電極」に相当する。 The piezoelectric transformer 171 includes a first electrode E51, a second electrode E52, a third electrode E53, and a fourth electrode E54. The piezoelectric transformer 172 includes a first electrode E61, a second electrode E62, a third electrode E63, and a fourth electrode E64. The first electrodes E51 and E61 correspond to “first voltage input electrodes” according to the present invention. The second electrodes E52 and E62 correspond to the “second voltage input electrode” according to the present invention. The third electrodes E53 and E63 correspond to the “first voltage output electrode” according to the present invention. The fourth electrodes E54 and E64 correspond to the “second voltage output electrode” according to the present invention.
　圧電トランス１７１の第１電極Ｅ５１及び第２電極Ｅ５２は電源回路１１に接続されている。第３電極Ｅ５３は、アクティブ電極１３に接続されている。第４電極Ｅ５４は、圧電トランス１７２の第３電極Ｅ６３、及び、送電装置１０５の基準電位に接続されている。 The first electrode E51 and the second electrode E52 of the piezoelectric transformer 171 are connected to the power supply circuit 11. The third electrode E53 is connected to the active electrode 13. The fourth electrode E54 is connected to the third electrode E63 of the piezoelectric transformer 172 and the reference potential of the power transmission device 105.
　圧電トランス１７２の第１電極Ｅ６１及び第２電極Ｅ６２は、電源回路１１に接続されている。第３電極Ｅ６３は、圧電トランス１７１の第４電極Ｅ５４、及び、送電装置１０５の基準電位に接続されている。第４電極Ｅ６４は、パッシブ電極１４に接続されている。 The first electrode E61 and the second electrode E62 of the piezoelectric transformer 172 are connected to the power supply circuit 11. The third electrode E63 is connected to the fourth electrode E54 of the piezoelectric transformer 171 and the reference potential of the power transmission device 105. The fourth electrode E64 is connected to the passive electrode 14.
　なお、圧電トランス１７１の第２電極Ｅ５２と、圧電トランス１７２の第１電極Ｅ６１とはそれぞれ、電源回路１１に接続しているが、圧電トランス１７１の第２電極Ｅ５２と、圧電トランス１７２の第１電極Ｅ６１とが互いに接続された構成でもよい。 The second electrode E52 of the piezoelectric transformer 171 and the first electrode E61 of the piezoelectric transformer 172 are connected to the power supply circuit 11, respectively, but the second electrode E52 of the piezoelectric transformer 171 and the first electrode of the piezoelectric transformer 172 are connected. The electrode E61 may be connected to each other.
　圧電トランス１７１，１７２には電極間に寄生容量（キャパシタ）が生じる。圧電トランス１７１の第１電極Ｅ５１及び第２電極Ｅ５２間に生じる寄生容量をＣ３１で表し、第３電極Ｅ５３及び第４電極Ｅ５４間に生じる寄生容量をＣ３２で表す。また、第１電極Ｅ５１及び第２電極Ｅ５２と第３電極Ｅ５３及び第４電極Ｅ５４との間に生じる寄生容量をＣ３３で表す。 In the piezoelectric transformers 171 and 172, a parasitic capacitance (capacitor) is generated between the electrodes. A parasitic capacitance generated between the first electrode E51 and the second electrode E52 of the piezoelectric transformer 171 is represented by C31, and a parasitic capacitance generated between the third electrode E53 and the fourth electrode E54 is represented by C32. Further, a parasitic capacitance generated between the first electrode E51 and the second electrode E52 and the third electrode E53 and the fourth electrode E54 is represented by C33.
　また、圧電トランス１７２の第１電極Ｅ６１及び第２電極Ｅ６２間に生じる寄生容量をＣ４１で表し、第３電極Ｅ６３及び第４電極Ｅ６４間に生じる寄生容量をＣ４２で表す。また、第１電極Ｅ６１及び第２電極Ｅ６２間と第３電極Ｅ６３及び第４電極Ｅ６４との間に生じる寄生容量をＣ４３で表す。 Further, the parasitic capacitance generated between the first electrode E61 and the second electrode E62 of the piezoelectric transformer 172 is represented by C41, and the parasitic capacitance generated between the third electrode E63 and the fourth electrode E64 is represented by C42. A parasitic capacitance generated between the first electrode E61 and the second electrode E62 and between the third electrode E63 and the fourth electrode E64 is represented by C43.
　受電装置２０５は、アクティブ電極２３及びパッシブ電極２４に誘起される電圧を降圧し、ダイオードブリッジＤＢへ供給する降圧部２７を備えている。降圧部２７は、二つの圧電トランス２７１，２７２を有している。圧電トランス２７１は、本発明に係る「第１圧電トランス」に相当する。圧電トランス２７２は、本発明に係る「第２圧電トランス」に相当する。 The power receiving device 205 includes a step-down unit 27 that steps down the voltage induced in the active electrode 23 and the passive electrode 24 and supplies the voltage to the diode bridge DB. The step-down unit 27 has two piezoelectric transformers 271 and 272. The piezoelectric transformer 271 corresponds to a “first piezoelectric transformer” according to the present invention. The piezoelectric transformer 272 corresponds to a “second piezoelectric transformer” according to the present invention.
　圧電トランス２７１は、第１電極Ｅ７１、第２電極Ｅ７２、第３電極Ｅ７３及び第４電極Ｅ７４を備えている。圧電トランス２７２は、第１電極Ｅ８１、第２電極Ｅ８２、第３電極Ｅ８３及び第４電極Ｅ８４を備えている。第１電極Ｅ７１，Ｅ８１は、本発明に係る「第１電圧入力電極」に相当する。第２電極Ｅ７２，Ｅ８２は、本発明に係る「第２電圧入力電極」に相当する。第３電極Ｅ７３，Ｅ８３は、本発明に係る「第１電圧出力電極」に相当する。第４電極Ｅ７４，Ｅ８４は、本発明に係る「第２電圧出力電極」に相当する。 The piezoelectric transformer 271 includes a first electrode E71, a second electrode E72, a third electrode E73, and a fourth electrode E74. The piezoelectric transformer 272 includes a first electrode E81, a second electrode E82, a third electrode E83, and a fourth electrode E84. The first electrodes E71 and E81 correspond to the “first voltage input electrode” according to the present invention. The second electrodes E72 and E82 correspond to the “second voltage input electrode” according to the present invention. The third electrodes E73 and E83 correspond to the “first voltage output electrode” according to the present invention. The fourth electrodes E74 and E84 correspond to the “second voltage output electrode” according to the present invention.
　圧電トランス２７１の第１電極Ｅ７１は、アクティブ電極２３に接続されている。第２電極Ｅ７２は、圧電トランス２７２の第１電極Ｅ８１、及び、受電装置２０５の基準電位に接続されている。第３電極Ｅ７３及び第４電極Ｅ７４は、ダイオードブリッジＤＢに接続されている。 The first electrode E71 of the piezoelectric transformer 271 is connected to the active electrode 23. The second electrode E72 is connected to the first electrode E81 of the piezoelectric transformer 272 and the reference potential of the power receiving device 205. The third electrode E73 and the fourth electrode E74 are connected to the diode bridge DB.
　圧電トランス２７２の第１電極Ｅ８１は、圧電トランス２７１の第２電極Ｅ７２、及び、受電装置２０５の基準電位に接続されている。第２電極Ｅ８２は、パッシブ電極２４に接続されている。第３電極Ｅ８３及び第４電極Ｅ８４は、ダイオードブリッジＤＢに接続されている。 The first electrode E81 of the piezoelectric transformer 272 is connected to the second electrode E72 of the piezoelectric transformer 271 and the reference potential of the power receiving device 205. The second electrode E82 is connected to the passive electrode 24. The third electrode E83 and the fourth electrode E84 are connected to the diode bridge DB.
　なお、圧電トランス２７１の第４電極Ｅ７４と、圧電トランス２７２の第３電極Ｅ８３とはそれぞれ、ダイオードブリッジＤＢに接続しているが、圧電トランス２７１の第４電極Ｅ７４と、圧電トランス２７２の第３電極Ｅ８３とが互いに接続された構成でもよい。 Although the fourth electrode E74 of the piezoelectric transformer 271 and the third electrode E83 of the piezoelectric transformer 272 are connected to the diode bridge DB, respectively, the fourth electrode E74 of the piezoelectric transformer 271 and the third electrode of the piezoelectric transformer 272 are connected. The electrode E83 may be connected to each other.
　圧電トランス２７１，２７２には電極間に寄生容量が生じる。圧電トランス２７１の第１電極Ｅ７１及び第２電極Ｅ７２間に生じる寄生容量をＣ５１で表し、第３電極Ｅ７３及び第４電極Ｅ７４間に生じる寄生容量をＣ５２で表す。また、第１電極Ｅ７１及び第２電極Ｅ７２と第３電極Ｅ７３及び第４電極Ｅ７４との間に生じる寄生容量をＣ５３で表す。 In the piezoelectric transformers 271 and 272, parasitic capacitance is generated between the electrodes. A parasitic capacitance generated between the first electrode E71 and the second electrode E72 of the piezoelectric transformer 271 is represented by C51, and a parasitic capacitance generated between the third electrode E73 and the fourth electrode E74 is represented by C52. Further, the parasitic capacitance generated between the first electrode E71 and the second electrode E72 and the third electrode E73 and the fourth electrode E74 is represented by C53.
　また、圧電トランス２７２の第１電極Ｅ８１及び第２電極Ｅ８２間に生じる寄生容量をＣ６１で表し、第３電極Ｅ８３及び第４電極Ｅ８４間に生じる寄生容量をＣ６２で表す。また、第１電極Ｅ８１及び第２電極Ｅ８２と第３電極Ｅ８３及び第４電極Ｅ８４との間に生じる寄生容量をＣ６３で表す。 Further, the parasitic capacitance generated between the first electrode E81 and the second electrode E82 of the piezoelectric transformer 272 is represented by C61, and the parasitic capacitance generated between the third electrode E83 and the fourth electrode E84 is represented by C62. A parasitic capacitance generated between the first electrode E81 and the second electrode E82 and the third electrode E83 and the fourth electrode E84 is represented by C63.
　ここで、圧電トランス１７１，１７２，２７１，２７２の具体的構成について説明する。本実施形態では、圧電トランス１７１，１７２，２７１，２７２はそれぞれ別の圧電体素体に形成されている。圧電トランス１７１，１７２，２７１，２７２それぞれは同じ構成であり、入力側、出力側ともに圧電対素体の厚み方向に分極されている。以下では、圧電トランス２７１について説明する。 Here, a specific configuration of the piezoelectric transformers 171, 172, 271, 272 will be described. In the present embodiment, the piezoelectric transformers 171, 172, 271, and 272 are formed on separate piezoelectric element bodies. The piezoelectric transformers 171, 172, 271, and 272 have the same configuration, and are polarized in the thickness direction of the piezoelectric element body on both the input side and the output side. Hereinafter, the piezoelectric transformer 271 will be described.
　図１１は、実施形態５に係る圧電トランス２７１の一例を示す図である。圧電トランス２７１は、例えばＰＺＴ系セラミックスシートが積層されて形成された圧電体３０１を備えている。圧電体３０１は、長さ方向に沿って、高インピーダンスの駆動部Ａ１と、低インピーダンスの発電部Ａ２と、駆動部Ａ１及び発電部Ａ２の間に形成された絶縁部Ａ３とを有している。 FIG. 11 is a diagram illustrating an example of the piezoelectric transformer 271 according to the fifth embodiment. The piezoelectric transformer 271 includes a piezoelectric body 301 formed by stacking, for example, PZT ceramic sheets. The piezoelectric body 301 has, along the length direction, a high impedance drive unit A1, a low impedance power generation unit A2, and an insulation unit A3 formed between the drive unit A1 and the power generation unit A2. .
　駆動部Ａ１での圧電体３０１は厚み方向に分極されている。そして、駆動部Ａ１では、圧電体３０１内部に内部電極３０２，３０３が厚み方向に沿って交互に積層され、上下面に第１電極Ｅ７１及び第２電極Ｅ７２が設けられている。内部電極３０２は、側面電極３０４により第１電極Ｅ７１と接続され、内部電極３０３は、側面電極３０４に対向する位置に形成された側面電極（不図示）により第２電極Ｅ７２と接続されている。 The piezoelectric body 301 in the driving unit A1 is polarized in the thickness direction. In the drive unit A1, the internal electrodes 302 and 303 are alternately stacked in the thickness direction inside the piezoelectric body 301, and the first electrode E71 and the second electrode E72 are provided on the upper and lower surfaces. The internal electrode 302 is connected to the first electrode E71 by a side electrode 304, and the internal electrode 303 is connected to the second electrode E72 by a side electrode (not shown) formed at a position facing the side electrode 304.
　発電部Ａ２では、圧電体３０１の厚み方向に分極されている。発電部Ａ２では、圧電体３０１と内部電極３０５，３０６を交互に複数枚積層しており、上下面に第３電極Ｅ７３及び第４電極Ｅ７４が形成されている。内部電極３０５は、側面電極３０７により第３電極Ｅ７３と接続されている。破線で示す内部電極３０６は、側面電極３０７が形成された面側には露出せず、反対面側に露出している。そして、内部電極３０６は、側面電極３０７に対向する位置に形成された側面電極（不図示）により第４電極Ｅ７４と接続されている。 In the power generation unit A2, the piezoelectric body 301 is polarized in the thickness direction. In the power generation unit A2, a plurality of piezoelectric bodies 301 and internal electrodes 305 and 306 are alternately stacked, and a third electrode E73 and a fourth electrode E74 are formed on the upper and lower surfaces. The internal electrode 305 is connected to the third electrode E73 by the side electrode 307. The internal electrode 306 indicated by a broken line is not exposed on the surface side on which the side electrode 307 is formed, but is exposed on the opposite surface side. The internal electrode 306 is connected to the fourth electrode E74 by a side electrode (not shown) formed at a position facing the side electrode 307.
　この構造を有する圧電トランス２７１において、駆動部Ａ１の第１電極Ｅ７１及び第２電極Ｅ７２に交流電圧を入力して駆動させると、発電部Ａ２の第３電極Ｅ７３及び第４電極Ｅ７４から降圧された電圧が出力される。なお、図１１に示す構造の圧電トランスは、駆動部Ａ１、発電部Ａ２の積層構成を調整することにより、降圧及び昇圧の変圧比を設定できる。 In the piezoelectric transformer 271 having this structure, when an AC voltage is input to the first electrode E71 and the second electrode E72 of the drive unit A1 and driven, the voltage is stepped down from the third electrode E73 and the fourth electrode E74 of the power generation unit A2. A voltage is output. In the piezoelectric transformer having the structure shown in FIG. 11, the step-down and step-up voltage transformation ratios can be set by adjusting the laminated configuration of the drive unit A1 and the power generation unit A2.
　図１２は、図１０に示すワイヤレス電力伝送システム５の等価回路図である。図１２では、昇圧部１７の圧電トランス１７１，１７２、及び、降圧部２７の圧電トランス２７１，２７２それぞれを、等価回路で示している。 FIG. 12 is an equivalent circuit diagram of the wireless power transmission system 5 shown in FIG. In FIG. 12, the piezoelectric transformers 171 and 172 of the booster unit 17 and the piezoelectric transformers 271 and 272 of the step-down unit 27 are shown as equivalent circuits.
　昇圧部１７は変圧部１７０を有している。この変圧部１７０は電源回路１１と、アクティブ電極１３及びパッシブ電極１４との間に接続されている。また、圧電トランス１７１，１７２に生じるキャパシタＣ３３，Ｃ４３の直列回路と、キャパシタＣ３２，Ｃ４２の直列回路とが、アクティブ電極１３及びパッシブ電極１４の間に接続されている。キャパシタＣ３３，Ｃ４３の接続点、及び、キャパシタＣ３２，Ｃ４２の接続点は、それぞれ基準電位に接続されている。 The booster 17 has a transformer 170. The transformer 170 is connected between the power supply circuit 11 and the active electrode 13 and the passive electrode 14. A series circuit of capacitors C33 and C43 generated in the piezoelectric transformers 171 and 172 and a series circuit of capacitors C32 and C42 are connected between the active electrode 13 and the passive electrode 14. The connection points of the capacitors C33 and C43 and the connection points of the capacitors C32 and C42 are respectively connected to the reference potential.
　なお、図１２では、圧電トランス１７１，１７２に生じるキャパシタＣ３１，Ｃ４１の図示は省略している。 In FIG. 12, the capacitors C31 and C41 generated in the piezoelectric transformers 171 and 172 are not shown.
　降圧部２７は変圧部２７０を有している。この変圧部２７０は、アクティブ電極２３及びパッシブ電極２４と、ダイオードブリッジＤＢとの間に接続されている。また、圧電トランス２７１，２７２に生じるキャパシタＣ５１，Ｃ６１の直列回路と、キャパシタＣ５３，Ｃ６３の直列回路とが、アクティブ電極２３及びパッシブ電極２４の間に接続されている。キャパシタＣ５１，Ｃ６１の接続点、及び、キャパシタＣ５３，Ｃ６３の接続点は基準電位に接続されている。図１２では、圧電トランス２７１，２７２に生じるキャパシタＣ５２，Ｃ６２の図示は省略している。 The step-down unit 27 has a transformer 270. The transformer 270 is connected between the active electrode 23 and the passive electrode 24 and the diode bridge DB. A series circuit of capacitors C51 and C61 generated in the piezoelectric transformers 271 and 272 and a series circuit of capacitors C53 and C63 are connected between the active electrode 23 and the passive electrode 24. The connection point between the capacitors C51 and C61 and the connection point between the capacitors C53 and C63 are connected to a reference potential. In FIG. 12, the capacitors C52 and C62 generated in the piezoelectric transformers 271 and 272 are not shown.
　この回路構成において、送電装置１０５の昇圧部１７では、並列接続されたキャパシタＣ３２，Ｃ３３と、並列接続されたキャパシタＣ４２，Ｃ４３とが、直列接続された構成と等価的に表せる。また、受電装置２０５の降圧部２７では、並列接続されたキャパシタＣ５１，Ｃ５３と、並列接続されたキャパシタＣ６１，Ｃ６３とが、直列接続された構成と等価的に表せる。 In this circuit configuration, the booster unit 17 of the power transmission device 105 can be equivalently expressed as a configuration in which the capacitors C32 and C33 connected in parallel and the capacitors C42 and C43 connected in parallel are connected in series. In addition, in the step-down unit 27 of the power receiving device 205, capacitors C51 and C53 connected in parallel and capacitors C61 and C63 connected in parallel can be equivalently expressed as a series connection.
　ここで、キャパシタＣ３２，Ｃ３３，Ｃ４２，Ｃ４３，Ｃ５１，Ｃ５３，Ｃ６１，Ｃ６３それぞれのキャパシタンスをＣ３２，Ｃ３３，Ｃ４２，Ｃ４３，Ｃ５１，Ｃ５３，Ｃ６１，Ｃ６３で表す。この場合、図１２に示すキャパシタＣ３２，Ｃ３３，Ｃ４２，Ｃ４３は、Ｃ３２＋Ｃ３３のキャパシタンスを有するキャパシタと、Ｃ４２＋Ｃ４３のキャパシタンスを有するキャパシタとが直列接続された構成で表せる。また、図１２に示すキャパシタＣ５１，Ｃ５３，Ｃ６１，Ｃ６３は、Ｃ５１＋Ｃ５３のキャパシタンスを有するキャパシタと、Ｃ６１＋Ｃ６３のキャパシタンスを有するキャパシタとが直列接続された構成となる。 Here, the capacitances of the capacitors C32, C33, C42, C43, C51, C53, C61, and C63 are represented by C32, C33, C42, C43, C51, C53, C61, and C63, respectively. In this case, the capacitors C32, C33, C42, and C43 shown in FIG. 12 can be expressed by a configuration in which a capacitor having a capacitance of C32 + C33 and a capacitor having a capacitance of C42 + C43 are connected in series. Further, the capacitors C51, C53, C61, and C63 shown in FIG. 12 have a configuration in which a capacitor having a capacitance of C51 + C53 and a capacitor having a capacitance of C61 + C63 are connected in series.
　この場合、実施形態１で説明したように、パッシブ電極１４，２４の面積は、アクティブ電極１３，２３の面積よりも大きい、又は同じであり、Ｃａａ≦Ｃｐｐの関係が成り立つ。そして、Ｃ３２＋Ｃ３３≦Ｃ４２＋Ｃ４３、かつ、Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３を満たすように、圧電トランス１７１，１７２，２７１，２７２を選択する。これにより、受電装置２０５の基準電位の変動を抑制できる。そして、その結果、基準電位の変動による不具合、例えば、装置の誤作動等を防止できる。 In this case, as described in the first embodiment, the area of the passive electrodes 14 and 24 is larger than or equal to the area of the active electrodes 13 and 23, and the relationship of Caa ≦ Cpp is established. Then, the piezoelectric transformers 171, 172, 271, and 272 are selected so that C32 + C33 ≦ C42 + C43 and C51 + C53 ≦ C61 + C63 are satisfied. Thereby, the fluctuation | variation of the reference electric potential of the power receiving apparatus 205 can be suppressed. As a result, problems due to fluctuations in the reference potential, for example, malfunction of the device can be prevented.
　以下に、圧電トランス１７１，１７２，２７１，２７２に生じる寄生容量の測定方法について説明する。 Hereinafter, a method for measuring the parasitic capacitance generated in the piezoelectric transformers 171, 172, 271 and 272 will be described.
　図１３は、圧電トランス２７１に生じる寄生容量の測定方法を説明するための図である。なお、図１３では、圧電トランス２７１に生じる寄生容量の測定方法について説明するが、他の圧電トランス１７１，１７２，２７２に生じる寄生容量の測定方法も同様である。 FIG. 13 is a diagram for explaining a method for measuring the parasitic capacitance generated in the piezoelectric transformer 271. In FIG. 13, a method for measuring the parasitic capacitance generated in the piezoelectric transformer 271 is described, but the method for measuring the parasitic capacitance generated in the other piezoelectric transformers 171, 172, 272 is the same.
　圧電トランス２７１の第１電極Ｅ７１に定電流源１５０を接続し、第２電極Ｅ７２はグランドに接続する。また、第３電極Ｅ７３及び第４電極Ｅ７４は短絡し、グランドに接続する。この接続構成において、キャパシタＣ５３のキャパシタンスは、圧電トランス２７１に入力される電圧Ｖｉｎと、圧電トランス２７１から出力される電流Ｉｏｕｔとから、Ｃ５３＝Ｉｏｕｔ／２πｆＶｉｎの式により求めることができる。 The constant current source 150 is connected to the first electrode E71 of the piezoelectric transformer 271 and the second electrode E72 is connected to the ground. The third electrode E73 and the fourth electrode E74 are short-circuited and connected to the ground. In this connection configuration, the capacitance of the capacitor C53 can be obtained from the voltage Vin input to the piezoelectric transformer 271 and the current Iout output from the piezoelectric transformer 271 by the equation C53 = Iout / 2πfVin.
　なお、圧電トランス２７１に生じるキャパシタＣ５１は、第１電極Ｅ７１及び第２電極Ｅ７２間に生じる容量、キャパシタＣ５２は、第３電極Ｅ７３及び第４電極Ｅ７４間に生じる容量である。したがって、例えば、キャパシタＣ５１のキャパシタンスは、第１電極Ｅ７１と第２電極Ｅ７２との間の容量を測定することで得られる。また、キャパシタＣ５２のキャパシタンスは、第３電極Ｅ７３と第４電極Ｅ７４との間の容量を測定することで得られる。 The capacitor C51 generated in the piezoelectric transformer 271 is a capacitance generated between the first electrode E71 and the second electrode E72, and the capacitor C52 is a capacitance generated between the third electrode E73 and the fourth electrode E74. Therefore, for example, the capacitance of the capacitor C51 can be obtained by measuring the capacitance between the first electrode E71 and the second electrode E72. Further, the capacitance of the capacitor C52 is obtained by measuring the capacitance between the third electrode E73 and the fourth electrode E74.
　以上のように、Ｃ３２＋Ｃ３３≦Ｃ４２＋Ｃ４３、かつ、Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３の条件が満たされるように、圧電トランス１７１，１７２，２７１，２７２を選択することで、受電装置２０５の基準電位の変動を抑制できる。そして、その結果、基準電位の変動による不具合、例えば、装置の誤作動等を防止できる。 As described above, by selecting the piezoelectric transformers 171, 172, 271, and 272 so that the conditions of C32 + C33 ≦ C42 + C43 and C51 + C53 ≦ C61 + C63 are satisfied, fluctuations in the reference potential of the power receiving device 205 can be suppressed. As a result, problems due to fluctuations in the reference potential, for example, malfunction of the device can be prevented.
　なお、本実施形態では、送電装置１０５及び受電装置２０５それぞれが圧電トランスを備えた構成としているが、送電装置１０５及び受電装置２０５の一方のみが圧電トランスを備えていてもよい。 In the present embodiment, each of the power transmission device 105 and the power reception device 205 is configured to include a piezoelectric transformer, but only one of the power transmission device 105 and the power reception device 205 may include a piezoelectric transformer.
　送電装置１０５のみが圧電トランスを備えている場合、受電装置２０５の降圧部２７は、巻線トランスで構成される。そして、この場合、Ｃ３２＋Ｃ３３＜Ｃ４２＋Ｃ４３を満たすように、圧電トランス１７１，１７２を選択する。受電装置２０５のみが圧電トランスを備えている場合、送電装置１０５の昇圧部１７は、巻線トランスで構成される。そして、この場合、Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３を満たすように、圧電トランス２７１，２７２を選択する。 When only the power transmission device 105 includes a piezoelectric transformer, the step-down unit 27 of the power reception device 205 is configured by a winding transformer. In this case, the piezoelectric transformers 171 and 172 are selected so as to satisfy C32 + C33 <C42 + C43. When only the power receiving device 205 includes a piezoelectric transformer, the booster unit 17 of the power transmitting device 105 includes a winding transformer. In this case, the piezoelectric transformers 271 and 272 are selected so as to satisfy C51 + C53 ≦ C61 + C63.
　また、本実施形態では、受電装置２０５の降圧部２７において、圧電トランス２７１の入力電極Ｅ７２と、圧電トランス２７２の入力電極Ｅ８１とはそれぞれ基準電位に接続しているが、接続していなくてもよい。この場合、圧電トランス２７１，２７２の入力電極側と出力電極側とが絶縁状態となるため、グランド経由で入力電極側に流れ込むノイズを抑制できる。そして、この場合では、Ｃ５３≦Ｃ６３を満たすよう、圧電トランス２７１，２７２を選択することで、受電装置２０５の基準電位の変動を抑制できる。 In the present embodiment, in the step-down unit 27 of the power receiving device 205, the input electrode E72 of the piezoelectric transformer 271 and the input electrode E81 of the piezoelectric transformer 272 are connected to the reference potential, respectively. Good. In this case, since the input electrode side and the output electrode side of the piezoelectric transformers 271 and 272 are in an insulated state, noise flowing into the input electrode side via the ground can be suppressed. In this case, the variation of the reference potential of the power receiving device 205 can be suppressed by selecting the piezoelectric transformers 271 and 272 so as to satisfy C53 ≦ C63.
　同様に、送電装置１０５において、圧電トランス１７１の第４電極Ｅ５４と、圧電トランス１７２の第３電極Ｅ６３とが、送電装置１０５の基準電位に接続していなくてもよい。この場合では、Ｃ３３≦Ｃ４３を満たすよう、圧電トランス１７１，１７２を選択することで、受電装置２０５の基準電位の変動を抑制できる。 Similarly, in the power transmission device 105, the fourth electrode E54 of the piezoelectric transformer 171 and the third electrode E63 of the piezoelectric transformer 172 may not be connected to the reference potential of the power transmission device 105. In this case, the variation in the reference potential of the power receiving device 205 can be suppressed by selecting the piezoelectric transformers 171 and 172 to satisfy C33 ≦ C43.
（実施形態６）
　実施形態５では、入出力部がともに圧電体素体の厚み方向に分極された圧電トランスを用いているのに対し、本実施形態では、入力部もしくは出力部のいずれか一方が圧電体素体の長手方向に分極され、他方が厚み方向に分極された圧電トランスを用いている点で、実施形態５と相違する。以下、実施形態５との相違点について説明する。 (Embodiment 6)
In the fifth embodiment, the input / output unit uses a piezoelectric transformer that is polarized in the thickness direction of the piezoelectric element body, whereas in the present embodiment, either the input unit or the output unit is a piezoelectric element element. This embodiment is different from the fifth embodiment in that a piezoelectric transformer is used which is polarized in the longitudinal direction and the other is polarized in the thickness direction. Hereinafter, differences from the fifth embodiment will be described.
　図１４は、実施形態６に係るワイヤレス電力伝送システム６の回路図である。 FIG. 14 is a circuit diagram of the wireless power transmission system 6 according to the sixth embodiment.
　ワイヤレス電力伝送システム６が備える送電装置１０６は、電源回路１１からの交流電圧を昇圧し、アクティブ電極１３及びパッシブ電極１４へ印加する昇圧部１８を備えている。昇圧部１８は、二つの圧電トランス１８１，１８２を有している。圧電トランス１８１は、本発明に係る「第３圧電トランス」に相当する。圧電トランス１８２は、本発明に係る「第４圧電トランス」に相当する。 The power transmission device 106 included in the wireless power transmission system 6 includes a boosting unit 18 that boosts the AC voltage from the power supply circuit 11 and applies the boosted voltage to the active electrode 13 and the passive electrode 14. The booster 18 has two piezoelectric transformers 181 and 182. The piezoelectric transformer 181 corresponds to a “third piezoelectric transformer” according to the present invention. The piezoelectric transformer 182 corresponds to a “fourth piezoelectric transformer” according to the present invention.
　圧電トランス１８１は、第１電極Ｅ９１、第２電極Ｅ９２、第３電極Ｅ９３及び第４電極Ｅ９４を備えている。圧電トランス１７２は、第１電極Ｅ１０１、第２電極Ｅ１０２、第３電極Ｅ１０３及び第４電極Ｅ１０４を備えている。第１電極Ｅ９１，Ｅ１０１は、本発明に係る「第１電圧入力電極」に相当する。第２電極Ｅ９２，Ｅ１０２は、本発明に係る「第２電圧入力電極」に相当する。第３電極Ｅ９３，Ｅ１０３は、本発明に係る「第１電圧出力電極」に相当する。第４電極Ｅ９４，Ｅ１０４は、本発明に係る「第２電圧出力電極」に相当する。 The piezoelectric transformer 181 includes a first electrode E91, a second electrode E92, a third electrode E93, and a fourth electrode E94. The piezoelectric transformer 172 includes a first electrode E101, a second electrode E102, a third electrode E103, and a fourth electrode E104. The first electrodes E91 and E101 correspond to “first voltage input electrodes” according to the present invention. The second electrodes E92 and E102 correspond to the “second voltage input electrode” according to the present invention. The third electrodes E93 and E103 correspond to the “first voltage output electrode” according to the present invention. The fourth electrodes E94 and E104 correspond to the “second voltage output electrode” according to the present invention.
　圧電トランス１８１の第１電極Ｅ９１及び第２電極Ｅ９２は電源回路１１に接続されている。また、第１電極Ｅ９１は、送電装置１０６の基準電位にも接続されている。第３電極Ｅ９３はアクティブ電極１３に接続されている。第４電極Ｅ９４は、圧電トランス１８２の第３電極Ｅ１０３、及び、送電装置１０６の基準電位に接続されている。 The first electrode E91 and the second electrode E92 of the piezoelectric transformer 181 are connected to the power supply circuit 11. The first electrode E91 is also connected to the reference potential of the power transmission device 106. The third electrode E93 is connected to the active electrode 13. The fourth electrode E94 is connected to the third electrode E103 of the piezoelectric transformer 182 and the reference potential of the power transmission device 106.
　圧電トランス１８２の第１電極Ｅ１０１及び第２電極Ｅ１０２は、電源回路１１に接続されている。また、第１電極Ｅ１０１は、送電装置１０６の基準電位にも接続されている。第４電極Ｅ１０４はパッシブ電極１４に接続されている。第３電極Ｅ１０３は、圧電トランス１８１の第４電極Ｅ９４、及び、送電装置１０６の基準電位に接続されている。 The first electrode E101 and the second electrode E102 of the piezoelectric transformer 182 are connected to the power supply circuit 11. The first electrode E101 is also connected to the reference potential of the power transmission device 106. The fourth electrode E104 is connected to the passive electrode. The third electrode E103 is connected to the fourth electrode E94 of the piezoelectric transformer 181 and the reference potential of the power transmission device 106.
　圧電トランス１８１，１８２には電極間に寄生容量が生じる。圧電トランス１８１の第１電極Ｅ９１及び第２電極Ｅ９２と、第３電極Ｅ９３との間に生じる寄生容量をＣａ１で表し、第１電極Ｅ９１及び第２電極Ｅ９２と、第４電極Ｅ９４との間に生じる寄生容量をＣｂ１で表す。また、第１電極Ｅ９１と第２電極Ｅ９２との間に生じる寄生容量をＣｃ１で表す。 In the piezoelectric transformers 181 and 182, parasitic capacitance is generated between the electrodes. A parasitic capacitance generated between the first electrode E91 and the second electrode E92 of the piezoelectric transformer 181 and the third electrode E93 is represented by Ca1, and between the first electrode E91, the second electrode E92, and the fourth electrode E94. The resulting parasitic capacitance is represented by Cb1. Further, a parasitic capacitance generated between the first electrode E91 and the second electrode E92 is represented by Cc1.
　同様に、圧電トランス１８２の第１電極Ｅ１０１及び第２電極Ｅ１０２と、第３電極Ｅ１０３との間に生じる寄生容量をＣａ２で表し、第１電極Ｅ１０１及び第２電極Ｅ１０２と、第４電極Ｅ１０４との間に生じる寄生容量をＣｂ２で表す。また、第１電極Ｅ１０１と第２電極Ｅ１０２との間に生じる寄生容量をＣｃ２で表す。 Similarly, a parasitic capacitance generated between the first electrode E101 and the second electrode E102 of the piezoelectric transformer 182 and the third electrode E103 is represented by Ca2, and the first electrode E101, the second electrode E102, the fourth electrode E104, The parasitic capacitance generated during the period is represented by Cb2. A parasitic capacitance generated between the first electrode E101 and the second electrode E102 is represented by Cc2.
　ワイヤレス電力伝送システム６が備える受電装置２０６は、アクティブ電極２３及びパッシブ電極２４に誘起される電圧を降圧し、ダイオードブリッジＤＢへ供給する降圧部２８を備えている。降圧部２８は、二つの圧電トランス２８１，２８２を有している。圧電トランス２８１は、本発明に係る「第１圧電トランス」に相当する。圧電トランス２８２は、本発明に係る「第２圧電トランス」に相当する。 The power receiving device 206 included in the wireless power transmission system 6 includes a step-down unit 28 that steps down the voltage induced in the active electrode 23 and the passive electrode 24 and supplies the voltage to the diode bridge DB. The step-down unit 28 has two piezoelectric transformers 281 and 282. The piezoelectric transformer 281 corresponds to a “first piezoelectric transformer” according to the present invention. The piezoelectric transformer 282 corresponds to a “second piezoelectric transformer” according to the present invention.
　圧電トランス２８１は、第１電極Ｅ１１１、第２電極Ｅ１１２、第３電極Ｅ１１３及び第４電極Ｅ１１４を備えている。圧電トランス２８２は、第１電極Ｅ１２１、第２電極Ｅ１２２、第３電極Ｅ１２３及び第４電極Ｅ１２４を備えている。第１電極Ｅ１１１，Ｅ１２１は、本発明に係る「第１電圧出力電極」に相当する。第２電極Ｅ１１２，Ｅ１２２は、本発明に係る「第２電圧出力電極」に相当する。第３電極Ｅ１１３，Ｅ１２３は、本発明に係る「第１電圧入力電極」に相当する。第４電極Ｅ１１４，Ｅ１２４は、本発明に係る「第２電圧入力電極」に相当する。 The piezoelectric transformer 281 includes a first electrode E111, a second electrode E112, a third electrode E113, and a fourth electrode E114. The piezoelectric transformer 282 includes a first electrode E121, a second electrode E122, a third electrode E123, and a fourth electrode E124. The first electrodes E111 and E121 correspond to “first voltage output electrodes” according to the present invention. The second electrodes E112 and E122 correspond to the “second voltage output electrode” according to the present invention. The third electrodes E113 and E123 correspond to the “first voltage input electrode” according to the present invention. The fourth electrodes E114 and E124 correspond to “second voltage input electrodes” according to the invention.
　圧電トランス２８１の第１電極Ｅ１１１及び第２電極Ｅ１１２は、ダイオードブリッジＤＢに接続されている。第３電極Ｅ１１３はアクティブ電極２３に接続されている。第４電極Ｅ１１４は、圧電トランスＥ２８２の第３電極Ｅ１２３、及び、受電装置２０６の基準電位に接続されている。 The first electrode E111 and the second electrode E112 of the piezoelectric transformer 281 are connected to the diode bridge DB. The third electrode E113 is connected to the active electrode 23. The fourth electrode E114 is connected to the third electrode E123 of the piezoelectric transformer E282 and the reference potential of the power receiving device 206.
　圧電トランス２８２の第１電極Ｅ１２１及び第２電極Ｅ１２２は、ダイオードブリッジＤＢに接続されている。第４電極Ｅ１２４はパッシブ電極２４に接続されている。第３電極Ｅ１２３は、圧電トランスＥ２８１の第４電極Ｅ１１４、及び、受電装置２０６の基準電位に接続されている。 The first electrode E121 and the second electrode E122 of the piezoelectric transformer 282 are connected to the diode bridge DB. The fourth electrode E124 is connected to the passive electrode 24. The third electrode E123 is connected to the fourth electrode E114 of the piezoelectric transformer E281 and the reference potential of the power receiving device 206.
　圧電トランス２８１，２８２には電極間に寄生容量が生じる。圧電トランス２８１の第１電極Ｅ１１１及び第２電極Ｅ１１２と、第３電極Ｅ１１３との間に生じる寄生容量をＣａ３で表し、第１電極Ｅ１１１及び第２電極Ｅ１１２と、第４電極Ｅ１１４との間に生じる寄生容量をＣｂ３で表す。また、第１電極Ｅ１１１と第２電極Ｅ１１２との間に生じる寄生容量をＣｃ３で表す。 In the piezoelectric transformers 281 and 282, parasitic capacitance is generated between the electrodes. A parasitic capacitance generated between the first electrode E111 and the second electrode E112 of the piezoelectric transformer 281 and the third electrode E113 is represented by Ca3, and between the first electrode E111, the second electrode E112, and the fourth electrode E114. The resulting parasitic capacitance is represented by Cb3. A parasitic capacitance generated between the first electrode E111 and the second electrode E112 is represented by Cc3.
　同様に、圧電トランス２８２の第１電極Ｅ１２１及び第２電極Ｅ１２２と、第３電極Ｅ１２３との間に生じる寄生容量をＣａ４で表し、第１電極Ｅ１２１及び第２電極Ｅ１２２と、第４電極Ｅ１２４との間に生じる寄生容量をＣｂ４で表す。また、第１電極Ｅ１２１と第２電極Ｅ１２２との間に生じる寄生容量をＣｃ４で表す。 Similarly, a parasitic capacitance generated between the first electrode E121 and the second electrode E122 of the piezoelectric transformer 282 and the third electrode E123 is represented by Ca4, and the first electrode E121, the second electrode E122, and the fourth electrode E124 The parasitic capacitance generated during the period is represented by Cb4. Further, the parasitic capacitance generated between the first electrode E121 and the second electrode E122 is represented by Cc4.
　ここで、圧電トランス１８１，１８２，２８１，２８２の具体的構成について説明する。本実施形態では、圧電トランス１８１，１８２，２８１，２８２は、入力部もしくは出力部のいずれか一方が圧電体素体の長手方向に分極され、他方が厚み方向に分極された圧電トランスである。圧電トランス１８１，１８２，２８１，２８２それぞれは同じ構成であり、以下では、圧電トランス２８１について説明する。 Here, a specific configuration of the piezoelectric transformers 181, 182, 281 and 282 will be described. In the present embodiment, the piezoelectric transformers 181, 182, 281, and 282 are piezoelectric transformers in which one of the input unit and the output unit is polarized in the longitudinal direction of the piezoelectric body and the other is polarized in the thickness direction. Each of the piezoelectric transformers 181, 182, 281, and 282 has the same configuration, and the piezoelectric transformer 281 will be described below.
　図１５は、実施形態６に係る圧電トランス２８１の一例を示す図である。圧電トランス２８１は、例えばＰＺＴ系セラミックスシートが積層されて形成された圧電体４０１を備えている。 FIG. 15 is a diagram illustrating an example of the piezoelectric transformer 281 according to the sixth embodiment. The piezoelectric transformer 281 includes a piezoelectric body 401 formed by stacking, for example, PZT ceramic sheets.
　圧電トランス２８１は、（３λ／２）共振モードで長さ方向に振動するものとする。ここで、λは長さ方向の振動の１波長である。したがって、圧電体４０１の長さは（３λ／２）としている。ここで、圧電体４０１の幅及び厚みは（λ／２）未満とすることが好ましい。そうすることで、幅方向及び厚み方向の振動が長さ方向の振動に結合せず、圧電トランス２８１全体の振動が不安定とならない。 Suppose that the piezoelectric transformer 281 vibrates in the length direction in the (3λ / 2) resonance mode. Here, λ is one wavelength of vibration in the length direction. Therefore, the length of the piezoelectric body 401 is (3λ / 2). Here, the width and thickness of the piezoelectric body 401 are preferably less than (λ / 2). By doing so, the vibration in the width direction and the thickness direction is not coupled to the vibration in the length direction, and the vibration of the entire piezoelectric transformer 281 is not unstable.
　圧電体４０１は、第１領域Ｂ１、第２領域Ｂ２、第３領域Ｂ３が形成されている。各領域Ｂ１～Ｂ３の長さは、何れもλ／２である。 The piezoelectric body 401 has a first region B1, a second region B2, and a third region B3. Each of the regions B1 to B3 has a length of λ / 2.
　第１領域Ｂ１及び第３領域Ｂ３は、圧電体の長さ方向に平行に分極されており、第２領域Ｂ２は、厚み方向に平行に分極されている。第１領域Ｂ１と第３領域Ｂ３とは逆方向に分極されている。分極処理の方法としては、例えば、圧電体板を１７０℃の絶縁油中で２ｋＶ／ｍｍの電圧を印加する方法等が挙げられる。 The first region B1 and the third region B3 are polarized in parallel with the length direction of the piezoelectric body, and the second region B2 is polarized in parallel with the thickness direction. The first region B1 and the third region B3 are polarized in opposite directions. Examples of the polarization treatment method include a method of applying a voltage of 2 kV / mm to the piezoelectric plate in insulating oil at 170 ° C.
　第２領域Ｂ２には、第１電極Ｅ１１１及び第２電極Ｅ１１２が圧電体４０１の側面に対向するよう設けられている。また、第２領域Ｂ２には、厚み方向に積層された複数の内部電極４０２が設けられている。この内部電極４０２は、交互に第１電極Ｅ１１１及び第２電極Ｅ１１２に接続している。 In the second region B2, the first electrode E111 and the second electrode E112 are provided to face the side surface of the piezoelectric body 401. The second region B2 is provided with a plurality of internal electrodes 402 stacked in the thickness direction. The internal electrodes 402 are alternately connected to the first electrode E111 and the second electrode E112.
　同様に、第１領域Ｂ１には、一対の第３電極Ｅ１１３Ａ，１１３Ｂが圧電体４０１の側面に対向するよう設けられている。一対の第３電極Ｅ１１３Ａ，１１３Ｂは、図１４に示す第３電極Ｅ１１３に相当する。第１領域Ｂ１には、厚み方向に積層された複数の内部電極４０３が設けられている。この内部電極４０３は、全てが第３電極Ｅ１１３Ａ，１１３Ｂの両方に接続している。 Similarly, a pair of third electrodes E113A and 113B are provided in the first region B1 so as to face the side surface of the piezoelectric body 401. The pair of third electrodes E113A and 113B corresponds to the third electrode E113 shown in FIG. In the first region B1, a plurality of internal electrodes 403 stacked in the thickness direction are provided. All of the internal electrodes 403 are connected to both the third electrodes E113A and 113B.
　第３領域Ｂ３には、一対の第４電極Ｅ１１４Ａ，１１４Ｂが圧電体４０１の側面に対向するよう設けられている。一対の第４電極Ｅ１１４Ａ，１１４Ｂは、図１４に示す第４電極Ｅ１１４に相当する。第３領域Ｂ３には、厚み方向に積層された複数の内部電極４０４が設けられている。この内部電極４０４は、全てが第４電極Ｅ１１４Ａ，１１４Ｂの両方に接続している。 In the third region B3, a pair of fourth electrodes E114A and 114B are provided to face the side surface of the piezoelectric body 401. The pair of fourth electrodes E114A and 114B corresponds to the fourth electrode E114 shown in FIG. In the third region B3, a plurality of internal electrodes 404 stacked in the thickness direction are provided. All of the internal electrodes 404 are connected to both the fourth electrodes E114A and 114B.
　以上のように構成された圧電トランス２８１において、一対の第３電極Ｅ１１３Ａ，１１３Ｂ、及び、一対の第４電極Ｅ１１４Ａ，１１４Ｂから電圧が入力されると、第１領域Ｂ１及び第３領域Ｂ３には分極方向（長さ方向）に電界が加えられる。そして、逆圧電効果により分極方向、すなわち、圧電体４０１の長さ方向に縦振動が励振される。縦振動が励振されると、第２領域Ｂ２では分極方向に機械的歪みが生じ、圧電横効果により分極方向に電位差が発生する。この電位差により第２領域Ｂ２が低電圧部となり、第２領域Ｂ２の第１電極Ｅ１１１及び第２電極Ｅ１１２からから低電圧が取り出される。 In the piezoelectric transformer 281 configured as described above, when voltage is input from the pair of third electrodes E113A and 113B and the pair of fourth electrodes E114A and 114B, the first region B1 and the third region B3 An electric field is applied in the polarization direction (length direction). Then, longitudinal vibration is excited in the polarization direction, that is, the length direction of the piezoelectric body 401 by the inverse piezoelectric effect. When longitudinal vibration is excited, mechanical distortion occurs in the polarization direction in the second region B2, and a potential difference occurs in the polarization direction due to the piezoelectric transverse effect. Due to this potential difference, the second region B2 becomes a low voltage portion, and a low voltage is extracted from the first electrode E111 and the second electrode E112 in the second region B2.
　以下に、本実施形態に係る圧電トランス１８１，１８２，２８１，２８２に生じる寄生容量と、実施形態５に係る圧電トランス１７１，１７２，２７１，２７２に生じる寄生容量との関係について説明する。ここでは、本実施形態に係る圧電トランス２８１に生じるキャパシタＣａ３，Ｃｂ３，Ｃｃ３と、実施形態５に係る圧電トランス２７１に生じるキャパシタＣ５１，Ｃ５２，Ｃ５３（図１０参照）との関係を例に挙げて説明する。 Hereinafter, the relationship between the parasitic capacitance generated in the piezoelectric transformers 181, 182, 281, and 282 according to the present embodiment and the parasitic capacitance generated in the piezoelectric transformers 171, 172, 271, and 272 according to the fifth embodiment will be described. Here, the relationship between the capacitors Ca3, Cb3, Cc3 generated in the piezoelectric transformer 281 according to the present embodiment and the capacitors C51, C52, C53 (see FIG. 10) generated in the piezoelectric transformer 271 according to the fifth embodiment is taken as an example. explain.
　キャパシタＣａ３，Ｃｂ３，Ｃｃ３のキャパシタンスをそれぞれ、Ｃａ３，Ｃｂ３，Ｃｃ３で表すと、キャパシタＣ５１，Ｃ５２，Ｃ５３に対応するキャパシタンスはそれぞれ、Ｃ５１＝（１／Ｃａ３＋１／Ｃｂ３）－１、Ｃ５２＝Ｃｃ３、Ｃ５３＝Ｃａ３＋Ｃｂ３で表すことができる。 When the capacitances of the capacitors Ca3, Cb3, and Cc3 are represented by Ca3, Cb3, and Cc3, respectively, the capacitances corresponding to the capacitors C51, C52, and C53 are C51 = (1 / Ca3 + 1 / Cb3) −1 and C52 = Cc3, C53, respectively. = Ca3 + Cb3.
　同様に、圧電トランス１８１に生じるキャパシタＣａ１，Ｃｂ１，Ｃｃ１は、圧電トランス１７１に生じるキャパシタＣ３１，Ｃ３２，Ｃ３３と、同様の対応関係を有する。圧電トランス１８２に生じるキャパシタＣａ２，Ｃｂ２，Ｃｃ２は、圧電トランス１７２に生じるキャパシタＣ４１，Ｃ４２，Ｃ４３と、同様の対応関係を有する。圧電トランス２８２に生じるキャパシタＣａ４，Ｃｂ４，Ｃｃ４は、圧電トランス２７２に生じるキャパシタＣ６１，Ｃ６２，Ｃ６３と、同様の対応関係を有する。 Similarly, the capacitors Ca1, Cb1, and Cc1 generated in the piezoelectric transformer 181 have the same correspondence relationship as the capacitors C31, C32, and C33 generated in the piezoelectric transformer 171. The capacitors Ca2, Cb2, and Cc2 generated in the piezoelectric transformer 182 have the same correspondence relationship as the capacitors C41, C42, and C43 generated in the piezoelectric transformer 172. The capacitors Ca4, Cb4, and Cc4 generated in the piezoelectric transformer 282 have the same correspondence relationship as the capacitors C61, C62, and C63 generated in the piezoelectric transformer 272.
　これらの関係から、Ｃ３２＋Ｃ３３≦Ｃ４２＋Ｃ４３、かつ、Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３を満たすように、圧電トランス１８１，１８２，２８１，２８２を選択する。これにより、受電装置２０６の基準電位の変動を抑制できる。そして、その結果、基準電位の変動による不具合、例えば、装置の誤作動等を防止できる。 From these relationships, the piezoelectric transformers 181, 182, 281, and 282 are selected so as to satisfy C32 + C33 ≦ C42 + C43 and C51 + C53 ≦ C61 + C63. Thereby, the fluctuation | variation of the reference potential of the power receiving apparatus 206 can be suppressed. As a result, problems due to fluctuations in the reference potential, for example, malfunction of the device can be prevented.
　以下に、圧電トランス１８１，１８２，２８１，２８２に生じる寄生容量の測定方法について説明する。 Hereinafter, a method for measuring the parasitic capacitance generated in the piezoelectric transformers 181, 182, 281 and 282 will be described.
　図１６は、圧電トランス２８１に生じるキャパシタの測定方法を説明するための図である。なお、図１６では、圧電トランス２８１に生じるキャパシタの測定方法のみを説明するが、他の圧電トランス１８１，１８２，２８２に生じるキャパシタの測定方法も同様である。 FIG. 16 is a diagram for explaining a method for measuring a capacitor generated in the piezoelectric transformer 281. In FIG. 16, only the method for measuring the capacitor generated in the piezoelectric transformer 281 is described, but the method for measuring the capacitor generated in the other piezoelectric transformers 181, 182, and 282 is the same.
　圧電トランス２８１の第３電極Ｅ１１３に定電流源１５０を接続し、第４電極Ｅ１１４はグランドに接続する。また、第１電極Ｅ１１１及び第２電極Ｅ１１２は短絡し、グランドに接続する。この接続構成において、キャパシタＣａ３（＝キャパシタＣ５３）のキャパシタンスは、圧電トランス２８１に入力される電圧Ｖｉｎと、圧電トランス２８１から出力される電流Ｉｏｕｔとから、Ｃａ３＝Ｃ５３＝Ｉｏｕｔ／２πｆＶｉｎの式により求めることができる。 The constant current source 150 is connected to the third electrode E113 of the piezoelectric transformer 281 and the fourth electrode E114 is connected to the ground. The first electrode E111 and the second electrode E112 are short-circuited and connected to the ground. In this connection configuration, the capacitance of the capacitor Ca3 (= capacitor C53) is obtained from the voltage Vin input to the piezoelectric transformer 281 and the current Iout output from the piezoelectric transformer 281 by the equation Ca3 = C53 = Iout / 2πfVin. be able to.
　圧電トランス２８１の第３電極Ｅ１１３及び第４電極Ｅ１１４間の容量を測定することで、キャパシタＣａ３，Ｃｂ３を直列接続した場合のキャパシタンスが測定できる。これにより、前記のＣ５１＝（１／Ｃａ３＋１／Ｃｂ３）－１から、キャパシタンスＣ５１を測定できる。また、第１電極Ｅ１１１及び第２電極Ｅ１１２間の容量を測定することで、前記のＣ５２＝Ｃｃ３からキャパシタンスＣ５２を測定できる。 By measuring the capacitance between the third electrode E113 and the fourth electrode E114 of the piezoelectric transformer 281, the capacitance when the capacitors Ca3 and Cb3 are connected in series can be measured. Thereby, the capacitance C51 can be measured from the above-mentioned C51 = (1 / Ca3 + 1 / Cb3) −1 . Further, by measuring the capacitance between the first electrode E111 and the second electrode E112, the capacitance C52 can be measured from the aforementioned C52 = Cc3.
　以上のように、Ｃ３２＋Ｃ３３≦Ｃ４２＋Ｃ４３、かつ、Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３の条件が満たされるように、圧電トランス１８１，１８２，２８１，２８２を選択することで、受電装置２０６の基準電位の変動を抑制できる。そして、その結果、基準電位の変動による不具合、例えば、装置の誤作動等を防止できる。 As described above, by selecting the piezoelectric transformers 181, 182, 281, and 282 so that the conditions of C32 + C33 ≦ C42 + C43 and C51 + C53 ≦ C61 + C63 are satisfied, fluctuations in the reference potential of the power receiving device 206 can be suppressed. As a result, problems due to fluctuations in the reference potential, for example, malfunction of the device can be prevented.
１，５，６…ワイヤレス電力伝送システム
１１…電源回路
１２…昇圧トランス（第２トランス）
１３，２３…アクティブ電極
１４，２４…パッシブ電極
１５，１６,１７…昇圧部（第２トランス）
２５，２６，２７…降圧部（第１トランス）
１０１，１０２，１０３，１０５，１０６…送電装置
１６１，１７１…圧電トランス（第３圧電トランス）
１６２，１７２…圧電トランス（第４圧電トランス）
２０１，２０２，２０３，２０５，２０６…受電装置
２６１，２７１…圧電トランス（第１圧電トランス）
２６２，２８１…圧電トランス（第２圧電トランス）
Ｃ１１…キャパシタ（第１静電容量）
Ｃ１２…キャパシタ（第２静電容量）
Ｃ１３…キャパシタ（第３静電容量）
Ｃ１４…キャパシタ（第４静電容量）
Ｃ１５…キャパシタ（第１圧電トランスの入力容量）
Ｃ１６…キャパシタ（第２圧電トランスの入力容量）
Ｃ１７…キャパシタ（第３圧電トランスの入力容量）
Ｃ１８…キャパシタ（第４圧電トランスの入力容量）
Ｃｏ…キャパシタ
Ｃａ，Ｃｐ…キャパシタ
ＤＢ…ダイオードブリッジ
Ｅ１１，Ｅ２１…第１電極（電圧入力電極）
Ｅ３１，Ｅ４１…第１電極（電圧出力電極）
Ｅ５１，Ｅ６１，Ｅ７１，Ｅ８１，Ｅ９１，Ｅ１０１，Ｅ１１３，Ｅ１２３…第１電極（第１電圧入力電極）
Ｅ１２，Ｅ２２，Ｅ３２，Ｅ４２…第２電極（基準電位用電極）
Ｅ５２，Ｅ６２，Ｅ７２，Ｅ８２，Ｅ９２，Ｅ１０２，Ｅ１１４，Ｅ１２４…第２電極（第２電圧入力電極）
Ｅ１３，Ｅ２３…第３電極（電圧出力電極）
Ｅ３３，Ｅ４３…第３電極（電圧入力電極）
Ｅ５３，Ｅ６３，Ｅ７３，Ｅ８３，Ｅ９３，Ｅ１０３，Ｅ１１１，Ｅ１２１…第３電極（第１電圧出力電極）
Ｅ５４，Ｅ６４，Ｅ７４，Ｅ８４，Ｅ９４，Ｅ１０４，Ｅ１１２，Ｅ１２２…第３電極（第２電圧出力電極）
Ｌ１…インダクタ
Ｌ２…インダクタ
ｎ１…１次コイル
ｎ２…２次コイル
Ｒ１…抵抗成分
ＲＧ…受電装置側基準電位点
ＴＧ…送電装置側基準電位点
ＲＬ…負荷回路
Ｔ１１…巻線トランス（第３巻線トランス）
Ｔ１２…巻線トランス（第４巻線トランス）
Ｔ２１…巻線トランス（第１巻線トランス）
Ｔ２２…巻線トランス（第２巻線トランス）
Ｚ１，Ｚ２，Ｚ３，Ｚ４…インピーダンス DESCRIPTION OF SYMBOLS 1, 5, 6 ... Wireless electric power transmission system 11 ... Power supply circuit 12 ... Boost transformer (2nd transformer)
13, 23 ... Active electrodes 14, 24 ... Passive electrodes 15, 16, 17 ... Booster (second transformer)
25, 26, 27 ... Step-down unit (first transformer)
101, 102, 103, 105, 106 ... power transmission devices 161, 171 ... piezoelectric transformer (third piezoelectric transformer)
162, 172 ... Piezoelectric transformer (fourth piezoelectric transformer)
201, 202, 203, 205, 206 ... power receiving devices 261, 271 ... piezoelectric transformer (first piezoelectric transformer)
262, 281 ... Piezoelectric transformer (second piezoelectric transformer)
C11: Capacitor (first capacitance)
C12: Capacitor (second capacitance)
C13: Capacitor (third capacitance)
C14: Capacitor (fourth capacitance)
C15: Capacitor (input capacitance of the first piezoelectric transformer)
C16: Capacitor (input capacitance of the second piezoelectric transformer)
C17: Capacitor (input capacitance of the third piezoelectric transformer)
C18: Capacitor (input capacitance of the fourth piezoelectric transformer)
Co ... capacitor Ca, Cp ... capacitor DB ... diode bridge E11, E21 ... first electrode (voltage input electrode)
E31, E41 ... 1st electrode (voltage output electrode)
E51, E61, E71, E81, E91, E101, E113, E123... First electrode (first voltage input electrode)
E12, E22, E32, E42 ... Second electrode (reference potential electrode)
E52, E62, E72, E82, E92, E102, E114, E124 ... second electrode (second voltage input electrode)
E13, E23 ... Third electrode (voltage output electrode)
E33, E43 ... Third electrode (voltage input electrode)
E53, E63, E73, E83, E93, E103, E111, E121 ... Third electrode (first voltage output electrode)
E54, E64, E74, E84, E94, E104, E112, E122 ... Third electrode (second voltage output electrode)
L1 ... inductor L2 ... inductor n1 ... primary coil n2 ... secondary coil R1 ... resistance component RG ... power receiving device side reference potential point TG ... power transmission device side reference potential point RL ... load circuit T11 ... winding transformer (third winding) Trance)
T12 ... Winding transformer (fourth winding transformer)
T21 ... Winding transformer (first winding transformer)
T22 ... Winding transformer (second winding transformer)
Z1, Z2, Z3, Z4 ... impedance

Claims (17)

  1. 　送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、
    　前記第１トランスは、
    　１次コイル及び２次コイルを有し、前記１次コイルの第１端が前記受電側アクティブ電極に接続され、第２端が自装置の基準電位に接続された第１巻線トランスと、
    　１次コイル及び２次コイルを有し、前記１次コイルの第１端が前記受電側パッシブ電極に接続され、第２端が自装置の基準電位に接続された第２巻線トランスと、
    　を有し、
    　前記第１巻線トランスの前記１次コイルのインダクタンスをＬ１１、前記１次コイルの前記第１端と前記第２端との間に生じる第１静電容量をＣ１１、前記第２巻線トランスの１次コイルのインダクタンスをＬ１２、前記１次コイルの前記第１端と前記第２端との間に生じる第２静電容量をＣ１２、電力伝送の動作角周波数をωで表すと、
    　１／ωＣ１１＜ωＬ１１、１／ωＣ１２＜ωＬ１２である場合、Ｃ１１≦Ｃ１２であり、
    　１／ωＣ１１＞ωＬ１１、１／ωＣ１２＞ωＬ１２である場合、Ｌ１１≧Ｌ１２である、
    　受電装置。     The power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, the power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, and the voltage induced in the power receiving side active electrode and the power receiving side passive electrode are In a power receiving device including a first transformer to be applied and a load circuit to which a voltage excited by the first transformer is applied, power is transmitted from the power transmitting device by electric field coupling.
    The first transformer is
    A first winding transformer having a primary coil and a secondary coil, the first end of the primary coil being connected to the power-receiving-side active electrode, and the second end being connected to the reference potential of the device;
    A second winding transformer having a primary coil and a secondary coil, wherein a first end of the primary coil is connected to the power-receiving-side passive electrode, and a second end is connected to a reference potential of the device;
    Have
    The inductance of the primary coil of the first winding transformer is L11, the first capacitance generated between the first end and the second end of the primary coil is C11, and the inductance of the second winding transformer is Expressing the inductance of the primary coil as L12, the second capacitance generated between the first end and the second end of the primary coil as C12, and the operating angular frequency of power transmission as ω,
    When 1 / ωC11 <ωL11 and 1 / ωC12 <ωL12, C11 ≦ C12,
    When 1 / ωC11> ωL11 and 1 / ωC12> ωL12, L11 ≧ L12.
    Power receiving device.
  2. 　前記第１静電容量及び前記第２静電容量は、前記第１巻線トランス、及び前記第２巻線トランスの前記１次コイルの巻線間浮遊容量である、
    　請求項１に記載の受電装置。     The first capacitance and the second capacitance are stray capacitances between windings of the primary coil of the first winding transformer and the second winding transformer,
    The power receiving device according to claim 1.
  3. 　送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、
    　前記第１トランスは、
    　１次コイル及び２次コイルを有する第１巻線トランス及び第２巻線トランスを有し、
    　前記第１巻線トランスは、
    　前記１次コイルの第１端が前記受電側アクティブ電極に接続され、第２端が前記第２巻線トランスの１次コイルの第１端に接続された構成であり、
    　前記第２巻線トランスは、前記１次コイルの第２端が前記受電側パッシブ電極に接続された構成であり、
    　前記第１巻線トランスの前記１次コイル及び前記２次コイルの間の静電容量をＣ１３、前記第２巻線トランスの前記１次コイル及び前記２次コイルの間の静電容量をＣ１４で表すと、Ｃ１３≦Ｃ１４である、
    　受電装置。     The power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, the power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, and the voltage induced in the power receiving side active electrode and the power receiving side passive electrode are In a power receiving device including a first transformer to be applied and a load circuit to which a voltage excited by the first transformer is applied, power is transmitted from the power transmitting device by electric field coupling.
    The first transformer is
    A first winding transformer and a second winding transformer having a primary coil and a secondary coil;
    The first winding transformer
    A first end of the primary coil is connected to the power-receiving-side active electrode, and a second end is connected to a first end of the primary coil of the second winding transformer;
    The second winding transformer has a configuration in which a second end of the primary coil is connected to the power-receiving-side passive electrode,
    The capacitance between the primary coil and the secondary coil of the first winding transformer is C13, and the capacitance between the primary coil and the secondary coil of the second winding transformer is C14. When expressed, C13 ≦ C14.
    Power receiving device.
  4. 　送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、
    　前記第１トランスは、
    　電圧入力電極、電圧出力電極、及び、自装置の基準電位に接続される基準電位用電極を有する第１圧電トランス及び第２圧電トランスを有し、
    　前記第１圧電トランスは、
    　前記電圧入力電極が前記受電側アクティブ電極に接続され、前記電圧出力電極が、前記第２圧電トランスの前記電圧出力電極に接続された構成であり、
    　前記第２圧電トランスは、
    　前記電圧入力電極が前記受電側パッシブ電極に接続された構成であり、
    　前記第１圧電トランスの前記電圧入力電極と前記基準電位用電極との間に生じる静電容量をＣ１５、前記第２圧電トランスの前記電圧入力電極と前記基準電位用電極との間に生じる静電容量をＣ１６で表すと、Ｃ１５≦Ｃ１６である、
    　受電装置。     The power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, the power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, and the voltage induced in the power receiving side active electrode and the power receiving side passive electrode are In a power receiving device including a first transformer to be applied and a load circuit to which a voltage excited by the first transformer is applied, power is transmitted from the power transmitting device by electric field coupling.
    The first transformer is
    A first piezoelectric transformer and a second piezoelectric transformer having a voltage input electrode, a voltage output electrode, and a reference potential electrode connected to the reference potential of the device;
    The first piezoelectric transformer is
    The voltage input electrode is connected to the power receiving side active electrode, and the voltage output electrode is connected to the voltage output electrode of the second piezoelectric transformer,
    The second piezoelectric transformer is
    The voltage input electrode is connected to the power receiving side passive electrode,
    The electrostatic capacitance generated between the voltage input electrode of the first piezoelectric transformer and the reference potential electrode is C15, and the electrostatic capacitance generated between the voltage input electrode of the second piezoelectric transformer and the reference potential electrode. When the capacity is represented by C16, C15 ≦ C16.
    Power receiving device.
  5. 　送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、
    　前記第１トランスは、
    　第１電圧入力電極、第２電圧入力電極、第１電圧出力電極及び第２電圧出力電極を有する第１圧電トランス及び第２圧電トランスを有し、
    　前記第１圧電トランスは、
    　前記第１電圧入力電極が前記受電側アクティブ電極に接続され、前記第２電圧入力電極が、自装置の基準電位に接続された構成であり、
    　前記第２圧電トランスは、
    　前記第２電圧入力電極が前記受電側パッシブ電極に接続され、前記第１電圧入力電極が、前記第１圧電トランスの前記第２電圧入力電極、及び、自装置の基準電位に接続された構成であり、
    　前記第１圧電トランスの前記第１電圧入力電極と前記第２電圧入力電極との間に生じる静電容量をＣ５１、前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ５３で表し、
    　前記第２圧電トランスの前記第１電圧入力電極と前記第２電圧入力電極との間に生じる静電容量をＣ６１、前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ６３で表すと、
    　Ｃ５１＋Ｃ５３≦Ｃ６１＋Ｃ６３である、
    　受電装置。     The power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, the power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, and the voltage induced in the power receiving side active electrode and the power receiving side passive electrode are In a power receiving device including a first transformer to be applied and a load circuit to which a voltage excited by the first transformer is applied, power is transmitted from the power transmitting device by electric field coupling.
    The first transformer is
    A first piezoelectric transformer and a second piezoelectric transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode and a second voltage output electrode;
    The first piezoelectric transformer is
    The first voltage input electrode is connected to the power receiving side active electrode, and the second voltage input electrode is connected to a reference potential of the device itself,
    The second piezoelectric transformer is
    The second voltage input electrode is connected to the power-receiving-side passive electrode, and the first voltage input electrode is connected to the second voltage input electrode of the first piezoelectric transformer and a reference potential of the device itself. Yes,
    The capacitance generated between the first voltage input electrode and the second voltage input electrode of the first piezoelectric transformer is C51, the first voltage input electrode, the second voltage input electrode, and the first voltage output electrode. And the capacitance generated between the second voltage output electrode and C53 is represented by C53,
    The capacitance generated between the first voltage input electrode and the second voltage input electrode of the second piezoelectric transformer is C61, the first voltage input electrode, the second voltage input electrode, and the first voltage output electrode. And the capacitance generated between the second voltage output electrode and C63 is represented by C63,
    C51 + C53 ≦ C61 + C63,
    Power receiving device.
  6. 　送電装置の送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電装置の送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極に誘起される電圧が印加される第１トランスと、前記第１トランスにより励起された電圧が印加される負荷回路とを備え、電界結合により前記送電装置から電力が伝送される受電装置において、
    　前記第１トランスは、
    　第１電圧入力電極、第２電圧入力電極、第１電圧出力電極及び第２電圧出力電極を有する第１圧電トランス及び第２圧電トランスを有し、
    　前記第１圧電トランスは、
    　前記第１電圧入力電極が前記受電側アクティブ電極に接続された構成であり、
    　前記第２圧電トランスは、
    　前記第２電圧入力電極が前記受電側パッシブ電極に接続され、前記第１電圧入力電極が、前記第１圧電トランスの前記第２電圧入力電極に接続された構成であり、
    　前記第１圧電トランスの前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ５３で表し、
    　前記第２圧電トランスの前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ６３で表すと、
    　Ｃ５３≦Ｃ６３である、
    　受電装置。     The power receiving side active electrode facing the power transmitting side active electrode of the power transmitting device, the power receiving side passive electrode facing the power transmitting side passive electrode of the power transmitting device, and the voltage induced in the power receiving side active electrode and the power receiving side passive electrode are In a power receiving device including a first transformer to be applied and a load circuit to which a voltage excited by the first transformer is applied, power is transmitted from the power transmitting device by electric field coupling.
    The first transformer is
    A first piezoelectric transformer and a second piezoelectric transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode and a second voltage output electrode;
    The first piezoelectric transformer is
    The first voltage input electrode is connected to the power receiving side active electrode,
    The second piezoelectric transformer is
    The second voltage input electrode is connected to the power-receiving-side passive electrode, and the first voltage input electrode is connected to the second voltage input electrode of the first piezoelectric transformer,
    A capacitance generated between the first voltage input electrode and the second voltage input electrode of the first piezoelectric transformer and the first voltage output electrode and the second voltage output electrode is represented by C53.
    When the capacitance generated between the first voltage input electrode and the second voltage input electrode of the second piezoelectric transformer and the first voltage output electrode and the second voltage output electrode is represented by C63,
    C53 ≦ C63,
    Power receiving device.
  7. 　受電装置の受電側アクティブ電極に対向する送電側アクティブ電極と、前記受電装置の受電側パッシブ電極に対向する送電側パッシブ電極と、前記送電側アクティブ電極及び前記送電側パッシブ電極に印加する交流電圧が印加される第２トランスとを備え、電界結合により前記受電装置へ電力を伝送する送電装置において、
    　前記第２トランスは、
    　１次コイル及び２次コイルを有し、前記２次コイルの第１端が前記送電側アクティブ電極に接続され、第２端が自装置の基準電位に接続された第３巻線トランスと、
    　１次コイル及び２次コイルを有し、前記２次コイルの第１端が前記送電側パッシブ電極に接続され、第２端が自装置の基準電位に接続された第４巻線トランスと、
    　を有し、
    　前記第３巻線トランスの前記２次コイルのインダクタンスをＬ２１、前記１次コイルの前記第１端と前記第２端との間に生じる第１静電容量をＣ２１、前記第４巻線トランスの前記２次コイルのインダクタンスをＬ２２、前記２次コイルの前記第１端と前記第２端との間に生じる第２静電容量をＣ２２、電力伝送の動作角周波数をωで表すと、
    　１／ωＣ２１＜ωＬ２１、１／ωＣ２２＜ωＬ２２である場合、Ｃ２１≦Ｃ２２であり、
    　１／ωＣ２１＞ωＬ２１、１／ωＣ２２＞ωＬ２２である場合、Ｌ２１≧Ｌ２２である、
    　送電装置。     A power transmission side active electrode facing the power reception side active electrode of the power reception device, a power transmission side passive electrode facing the power reception side passive electrode of the power reception device, and an AC voltage applied to the power transmission side active electrode and the power transmission side passive electrode are A power transmission device including a second transformer to be applied and transmitting electric power to the power reception device by electric field coupling;
    The second transformer is
    A third winding transformer having a primary coil and a secondary coil, the first end of the secondary coil being connected to the power transmission side active electrode, and the second end being connected to the reference potential of the device itself;
    A fourth winding transformer having a primary coil and a secondary coil, a first end of the secondary coil being connected to the power transmission side passive electrode, and a second end being connected to a reference potential of the device;
    Have
    The inductance of the secondary coil of the third winding transformer is L21, the first capacitance generated between the first end and the second end of the primary coil is C21, and the inductance of the fourth winding transformer is C21. L22 represents the inductance of the secondary coil, C22 represents the second capacitance generated between the first end and the second end of the secondary coil, and ω represents the operating angular frequency of power transmission.
    When 1 / ωC21 <ωL21 and 1 / ωC22 <ωL22, C21 ≦ C22,
    When 1 / ωC21> ωL21 and 1 / ωC22> ωL22, L21 ≧ L22.
    Power transmission device.
  8. 　前記第１静電容量、及び前記第２静電容量は、前記第３巻線トランス、及び前記第４巻線トランスの前記２次コイルの巻線間浮遊容量である、
    　請求項７に記載の送電装置。     The first capacitance and the second capacitance are stray capacitances between windings of the secondary coil of the third winding transformer and the fourth winding transformer,
    The power transmission device according to claim 7.
  9. 　受電装置の受電側アクティブ電極に対向する送電側アクティブ電極と、前記受電装置の受電側パッシブ電極に対向する送電側パッシブ電極と、前記送電側アクティブ電極及び前記送電側パッシブ電極に印加する交流電圧が印加される第２トランスとを備え、電界結合により前記受電装置へ電力を伝送する送電装置において、
    　前記第２トランスは、
    　１次コイル及び２次コイルを有する第３巻線トランス及び第４巻線トランスを有し、
    　前記第３巻線トランスは、前記２次コイルの第１端が前記送電側アクティブ電極に接続され、第２端が前記第４巻線トランスの前記２次コイルの第１端に接続された構成であり、
    　前記第４巻線トランスは、前記２次コイルの第２端が前記送電側パッシブ電極に接続された構成であり、
    　前記第３巻線トランスの１次コイル、及び前記２次コイルの間の静電容量をＣ２３、前記第４巻線トランスの１次コイル、及び前記２次コイルの間の静電容量をＣ２４で表すと、Ｃ２３≦Ｃ２４である、
    　送電装置。     A power transmission side active electrode facing the power reception side active electrode of the power reception device, a power transmission side passive electrode facing the power reception side passive electrode of the power reception device, and an AC voltage applied to the power transmission side active electrode and the power transmission side passive electrode are A power transmission device including a second transformer to be applied and transmitting electric power to the power reception device by electric field coupling;
    The second transformer is
    Having a third winding transformer and a fourth winding transformer having a primary coil and a secondary coil;
    The third winding transformer has a configuration in which a first end of the secondary coil is connected to the power transmission side active electrode and a second end is connected to a first end of the secondary coil of the fourth winding transformer. And
    The fourth winding transformer has a configuration in which a second end of the secondary coil is connected to the power transmission side passive electrode,
    The capacitance between the primary coil and the secondary coil of the third winding transformer is C23, and the capacitance between the primary coil and the secondary coil of the fourth winding transformer is C24. Expressed as C23 ≦ C24,
    Power transmission device.
  10. 　受電装置の受電側アクティブ電極に対向する送電側アクティブ電極と、前記受電装置の受電側パッシブ電極に対向する送電側パッシブ電極と、前記送電側アクティブ電極及び前記送電側パッシブ電極に印加する交流電圧が印加される第２トランスとを備え、電界結合により前記受電装置へ電力を伝送する送電装置において、
    　前記第２トランスは、
    　電圧入力電極、電圧出力電極及び自装置の基準電位に接続される基準電位用電極を有する第３圧電トランス及び第４圧電トランスを有し、
    　前記第３圧電トランスは、
    　前記電圧出力電極が前記送電側アクティブ電極に接続され、前記電圧入力電極が、前記第４圧電トランスの前記電圧入力電極に接続された構成であり、
    　前記第４圧電トランスは、
    　前記電圧出力電極が前記送電側パッシブ電極に接続された構成であり、
    　前記第３圧電トランスの前記電圧出力電極と前記基準電位用電極との間に生じる静電容量をＣ２５、前記第４圧電トランスの前記電圧出力電極と前記基準電位用電極との間に生じる静電容量をＣ２６で表すと、Ｃ２５≦Ｃ２６である、
    　送電装置。     A power transmission side active electrode facing the power reception side active electrode of the power reception device, a power transmission side passive electrode facing the power reception side passive electrode of the power reception device, and an AC voltage applied to the power transmission side active electrode and the power transmission side passive electrode are A power transmission device including a second transformer to be applied and transmitting electric power to the power reception device by electric field coupling;
    The second transformer is
    A third piezoelectric transformer and a fourth piezoelectric transformer having a voltage input electrode, a voltage output electrode, and a reference potential electrode connected to the reference potential of the device;
    The third piezoelectric transformer is
    The voltage output electrode is connected to the power transmission side active electrode, and the voltage input electrode is connected to the voltage input electrode of the fourth piezoelectric transformer,
    The fourth piezoelectric transformer is
    The voltage output electrode is connected to the power transmission side passive electrode,
    The electrostatic capacity generated between the voltage output electrode of the third piezoelectric transformer and the reference potential electrode is C25, and the electrostatic capacity generated between the voltage output electrode of the fourth piezoelectric transformer and the reference potential electrode. When the capacity is represented by C26, C25 ≦ C26.
    Power transmission device.
  11. 　受電装置の受電側アクティブ電極に対向する送電側アクティブ電極と、前記受電装置の受電側パッシブ電極に対向する送電側パッシブ電極と、前記送電側アクティブ電極及び前記送電側パッシブ電極に印加する交流電圧が印加される第２トランスとを備え、電界結合により前記受電装置へ電力を伝送する送電装置において、
    　前記第２トランスは、
    　第１電圧入力電極、第２電圧入力電極、第１電圧出力電極及び第２電圧出力電極を有する第３圧電トランス及び第４圧電トランスを有し、
    　前記第３圧電トランスは、
    　前記第１電圧出力電極が前記送電側アクティブ電極に接続され、前記第２電圧出力電極が自装置の基準電位に接続された構成であり、
    　前記第４圧電トランスは、
    　前記第２電圧出力電極が前記送電側パッシブ電極に接続され、前記第１電圧出力電極が、前記第３圧電トランスの前記第２電圧出力電極、及び、自装置の基準電位に接続された構成であり、
    　前記第３圧電トランスの前記第１電圧出力電極と前記第２電圧出力電極との間に生じる静電容量をＣ３２、前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ３３で表し、
    　前記第４圧電トランスの前記第１電圧出力電極と前記第２電圧出力電極との間に生じる静電容量をＣ４２、前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ４３で表すと、
    　Ｃ３２＋Ｃ３３≦Ｃ４２＋Ｃ４３である、
    　送電装置。     A power transmission side active electrode facing the power reception side active electrode of the power reception device, a power transmission side passive electrode facing the power reception side passive electrode of the power reception device, and an AC voltage applied to the power transmission side active electrode and the power transmission side passive electrode are A power transmission device including a second transformer to be applied and transmitting electric power to the power reception device by electric field coupling;
    The second transformer is
    A third voltage transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode and a second voltage output electrode, and a fourth piezoelectric transformer;
    The third piezoelectric transformer is
    The first voltage output electrode is connected to the power transmission side active electrode, and the second voltage output electrode is connected to a reference potential of the device itself,
    The fourth piezoelectric transformer is
    The second voltage output electrode is connected to the power transmission side passive electrode, and the first voltage output electrode is connected to the second voltage output electrode of the third piezoelectric transformer and a reference potential of the device itself. Yes,
    The capacitance generated between the first voltage output electrode and the second voltage output electrode of the third piezoelectric transformer is C32, the first voltage input electrode, the second voltage input electrode, and the first voltage output electrode. And a capacitance generated between the second voltage output electrode and the second voltage output electrode is represented by C33,
    The capacitance generated between the first voltage output electrode and the second voltage output electrode of the fourth piezoelectric transformer is C42, the first voltage input electrode, the second voltage input electrode, and the first voltage output electrode. And the capacitance generated between the second voltage output electrode and the second voltage output electrode is represented by C43.
    C32 + C33 ≦ C42 + C43.
    Power transmission device.
  12. 　受電装置の受電側アクティブ電極に対向する送電側アクティブ電極と、前記受電装置の受電側パッシブ電極に対向する送電側パッシブ電極と、前記送電側アクティブ電極及び前記送電側パッシブ電極に印加する交流電圧が印加される第２トランスとを備え、電界結合により前記受電装置へ電力を伝送する送電装置において、
    　前記第２トランスは、
    　第１電圧入力電極、第２電圧入力電極、第１電圧出力電極及び第２電圧出力電極を有する第３圧電トランス及び第４圧電トランスを有し、
    　前記第３圧電トランスは、
    　前記第１電圧出力電極が前記送電側アクティブ電極に接続された構成であり、
    　前記第４圧電トランスは、
    　前記第２電圧出力電極が前記送電側パッシブ電極に接続され、前記第１電圧出力電極が、前記第３圧電トランスの前記第２電圧出力電極に接続された構成であり、
    　前記第３圧電トランスの前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ３３で表し、
    　前記第４圧電トランスの前記第１電圧入力電極及び前記第２電圧入力電極と前記第１電圧出力電極及び前記第２電圧出力電極との間に生じる静電容量をＣ４３で表すと、
    　Ｃ３３≦Ｃ４３である、
    　送電装置。     A power transmission side active electrode facing the power reception side active electrode of the power reception device, a power transmission side passive electrode facing the power reception side passive electrode of the power reception device, and an AC voltage applied to the power transmission side active electrode and the power transmission side passive electrode are A power transmission device including a second transformer to be applied and transmitting electric power to the power reception device by electric field coupling;
    The second transformer is
    A third voltage transformer having a first voltage input electrode, a second voltage input electrode, a first voltage output electrode and a second voltage output electrode, and a fourth piezoelectric transformer;
    The third piezoelectric transformer is
    The first voltage output electrode is connected to the power transmission side active electrode,
    The fourth piezoelectric transformer is
    The second voltage output electrode is connected to the power transmission side passive electrode, and the first voltage output electrode is connected to the second voltage output electrode of the third piezoelectric transformer,
    A capacitance generated between the first voltage input electrode and the second voltage input electrode of the third piezoelectric transformer and the first voltage output electrode and the second voltage output electrode is represented by C33,
    When the capacitance generated between the first voltage input electrode and the second voltage input electrode of the fourth piezoelectric transformer and the first voltage output electrode and the second voltage output electrode is represented by C43,
    C33 ≦ C43.
    Power transmission device.
  13. 　送電側アクティブ電極と、送電側パッシブ電極と、送電側アクティブ電極及び送電側パッシブ電極に交流電圧を印加する送電側トランスを有する送電装置と、
    　前記送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極の間に生じる電圧が印加される受電側トランスとを有する受電装置と、
    　を備え、
    　前記受電側トランスは、
    　１次コイル及び２次コイルを有し、前記１次コイルの第１端が前記受電側アクティブ電極に接続され、第２端が自装置の基準電位に接続された第１巻線トランスと、
    　１次コイル及び２次コイルを有し、前記１次コイルの第１端が前記受電側パッシブ電極に接続され、第２端が自装置の基準電位に接続された第２巻線トランスと、
    　を有し、
    　前記第１巻線トランスの前記１次コイルのインダクタンスをＬ１１、前記１次コイルの前記第１端と前記第２端との間に生じる第１静電容量をＣ１１、前記第２巻線トランスの１次コイルのインダクタンスをＬ１２、前記１次コイルの前記第１端と前記第２端との間に生じる第１静電容量をＣ１２、電力伝送の動作角周波数をωで表すと、
    　１／ωＣ１１＜ωＬ１１、１／ωＣ１２＜ωＬ１２である場合、Ｃ１１≦Ｃ１２であり、
    　１／ωＣ１１＞ωＬ１１、１／ωＣ１２＞ωＬ１２である場合、Ｌ１１≧Ｌ１２である、
    　ワイヤレス電力伝送システム。     A power transmission device including a power transmission side active electrode, a power transmission side passive electrode, a power transmission side active electrode, and a power transmission side transformer that applies an AC voltage to the power transmission side passive electrode;
    A power receiving side active electrode facing the power transmitting side active electrode, a power receiving side passive electrode facing the power transmitting side passive electrode, and a power receiving side to which a voltage generated between the power receiving side active electrode and the power receiving side passive electrode is applied. A power receiving device having a transformer;
    With
    The power receiving side transformer is:
    A first winding transformer having a primary coil and a secondary coil, the first end of the primary coil being connected to the power-receiving-side active electrode, and the second end being connected to the reference potential of the device;
    A second winding transformer having a primary coil and a secondary coil, wherein a first end of the primary coil is connected to the power-receiving-side passive electrode, and a second end is connected to a reference potential of the device;
    Have
    The inductance of the primary coil of the first winding transformer is L11, the first capacitance generated between the first end and the second end of the primary coil is C11, and the inductance of the second winding transformer is L12 represents the inductance of the primary coil, C12 represents the first capacitance generated between the first end and the second end of the primary coil, and ω represents the operating angular frequency of power transmission.
    When 1 / ωC11 <ωL11 and 1 / ωC12 <ωL12, C11 ≦ C12,
    When 1 / ωC11> ωL11 and 1 / ωC12> ωL12, L11 ≧ L12.
    Wireless power transmission system.
  14. 　送電側アクティブ電極と、送電側パッシブ電極と、送電側アクティブ電極及び送電側パッシブ電極に交流電圧を印加する送電側トランスを有する送電装置と、
    　前記送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極の間に生じる電圧が印加される受電側トランスとを有する受電装置と、
    　を備え、
    　前記送電側トランスは、
    　１次コイル及び２次コイルを有する第３巻線トランス、及び第４巻線トランスを有し、
    　前記第３巻線トランスは、前記２次コイルの第１端が前記送電側アクティブ電極に接続され、第２端が前記第４巻線トランスの前記２次コイルの第１端に接続された構成であり、
    　前記第４巻線トランスは、前記１次コイルの第２端が前記送電側パッシブ電極に接続された構成であり、
    　前記第３巻線トランスの１次コイル、及び前記２次コイルの間の静電容量をＣ１３、前記第４巻線トランスの１次コイル、及び前記２次コイルの間の静電容量をＣ１４で表すと、Ｃ１３≦Ｃ１４である、
    　ワイヤレス電力伝送システム。     A power transmission device including a power transmission side active electrode, a power transmission side passive electrode, a power transmission side active electrode, and a power transmission side transformer that applies an AC voltage to the power transmission side passive electrode;
    A power receiving side active electrode facing the power transmitting side active electrode, a power receiving side passive electrode facing the power transmitting side passive electrode, and a power receiving side to which a voltage generated between the power receiving side active electrode and the power receiving side passive electrode is applied. A power receiving device having a transformer;
    With
    The power transmission side transformer is:
    A third winding transformer having a primary coil and a secondary coil, and a fourth winding transformer;
    The third winding transformer has a configuration in which a first end of the secondary coil is connected to the power transmission side active electrode and a second end is connected to a first end of the secondary coil of the fourth winding transformer. And
    The fourth winding transformer has a configuration in which a second end of the primary coil is connected to the power transmission side passive electrode,
    The capacitance between the primary coil of the third winding transformer and the secondary coil is C13, and the capacitance between the primary coil of the fourth winding transformer and the secondary coil is C14. When expressed, C13 ≦ C14.
    Wireless power transmission system.
  15. 　送電側アクティブ電極と、送電側パッシブ電極と、送電側アクティブ電極及び送電側パッシブ電極に交流電圧を印加する送電側トランスを有する送電装置と、
    　前記送電側アクティブ電極に対向する受電側アクティブ電極と、前記送電側パッシブ電極に対向する受電側パッシブ電極と、前記受電側アクティブ電極及び前記受電側パッシブ電極の間に生じる電圧が印加される受電側トランスとを有する受電装置と、
    　を備え、
    　前記受電側トランスは、
    　電圧入力電極、電圧出力電極、及び、前記受電装置の基準電位に接続される基準電位用電極を有する第１圧電トランス、第２圧電トランスを有し、
    　前記第１圧電トランスは、
    　前記電圧入力電極が前記受電側アクティブ電極に接続され、前記電圧出力電極が、前記第２圧電トランスの前記電圧出力電極に接続された構成であり、
    　前記第２圧電トランスは、
    　前記電圧入力電極が前記受電側パッシブ電極に接続された構成であり、
    　前記第１圧電トランスの前記電圧入力電極と前記基準電位用電極との間に生じる静電容量をＣ１５、前記第２圧電トランスの前記電圧入力電極と前記基準電位用電極との間に生じる静電容量をＣ１６で表すと、Ｃ１５≦Ｃ１６である、
    　ワイヤレス電力伝送システム。     A power transmission device including a power transmission side active electrode, a power transmission side passive electrode, a power transmission side active electrode, and a power transmission side transformer that applies an AC voltage to the power transmission side passive electrode;
    A power receiving side active electrode facing the power transmitting side active electrode, a power receiving side passive electrode facing the power transmitting side passive electrode, and a power receiving side to which a voltage generated between the power receiving side active electrode and the power receiving side passive electrode is applied. A power receiving device having a transformer;
    With
    The power receiving side transformer is:
    A first piezoelectric transformer having a voltage input electrode, a voltage output electrode, and a reference potential electrode connected to a reference potential of the power receiving device; a second piezoelectric transformer;
    The first piezoelectric transformer is
    The voltage input electrode is connected to the power receiving side active electrode, and the voltage output electrode is connected to the voltage output electrode of the second piezoelectric transformer,
    The second piezoelectric transformer is
    The voltage input electrode is connected to the power receiving side passive electrode,
    The electrostatic capacitance generated between the voltage input electrode of the first piezoelectric transformer and the reference potential electrode is C15, and the electrostatic capacitance generated between the voltage input electrode of the second piezoelectric transformer and the reference potential electrode. When the capacity is represented by C16, C15 ≦ C16.
    Wireless power transmission system.
  16. 　前記送電側トランスは、
    　電圧入力電極、電圧出力電極、及び、前記送電装置の基準電位に接続される基準電位用電極を有する第３圧電トランス、第４圧電トランスを有し、
    　前記第３圧電トランスは、
    　前記電圧出力電極が前記送電側アクティブ電極に接続され、前記電圧入力電極が、前記第４圧電トランスの前記電圧入力電極に接続された構成であり、
    　前記第４圧電トランスは、
    　前記電圧出力電極が前記送電側パッシブ電極に接続された構成であり、
    　前記第３圧電トランスの前記電圧出力電極と前記基準電位用電極との間に生じる静電容量をＣ２５、前記第４圧電トランスの前記電圧出力電極と前記基準電位用電極との間に生じる静電容量をＣ２６で表すと、Ｃ２５≦Ｃ２６である、
    　請求項１５に記載のワイヤレス電力伝送システム。     The power transmission side transformer is:
    A third piezoelectric transformer having a voltage input electrode, a voltage output electrode, and a reference potential electrode connected to a reference potential of the power transmission device; a fourth piezoelectric transformer;
    The third piezoelectric transformer is
    The voltage output electrode is connected to the power transmission side active electrode, and the voltage input electrode is connected to the voltage input electrode of the fourth piezoelectric transformer,
    The fourth piezoelectric transformer is
    The voltage output electrode is connected to the power transmission side passive electrode,
    The electrostatic capacity generated between the voltage output electrode of the third piezoelectric transformer and the reference potential electrode is C25, and the electrostatic capacity generated between the voltage output electrode of the fourth piezoelectric transformer and the reference potential electrode. When the capacity is represented by C26, C25 ≦ C26.
    The wireless power transmission system according to claim 15.
  17. 　前記第１圧電トランス及び前記第３圧電トランスは、同一の圧電トランスであり、
    　前記第２圧電トランス及び前記第４圧電トランスは、同一の圧電トランスである、
    　請求項１６に記載のワイヤレス電力伝送システム。     The first piezoelectric transformer and the third piezoelectric transformer are the same piezoelectric transformer,
    The second piezoelectric transformer and the fourth piezoelectric transformer are the same piezoelectric transformer.
    The wireless power transmission system according to claim 16.
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