WIRELESS POWER-SUPPLYING SYSTEM

• US 20170256993A1
• Filed: 05/17/2017
• Published: 09/07/2017
• Est. Priority Date: 02/06/2015
• Status: Active Grant

• Current Assignee: IHI Corporation
• Original Assignee: IHI Corporation
• Inventors: NAKAMURA, Toshio, MURAYAMA, Takahiko, ARAKI, Jun
• Granted Patent: US 10,454,314 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 5/00 Current collectors for power supply lines of electrically-propelled vehicles current collectors in general H01R41/00
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60M 7/00 Power lines or rails specially adapted for electrically-propelled vehicles of special types, e.g. suspension tramway, ropeway, underground railway
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A wireless power-supplying system according to the present disclosure includes a power-transmitting device and a power-receiving device. The power-transmitting device includes a power-transmitting coil to which AC power of a certain frequency is input from a power supply and a controller which controls a frequency. The power-receiving device includes a power-receiving coil magnetically coupled with the power-transmitting coil with a certain coupling coefficient and a power-receiving side series element connected to the power-receiving coil in series and having imaginary impedance jZ_S2i. The imaginary impedance is defined so that impedance when a power-receiving side is seen from the power supply is independent of the coupling coefficient when the frequency and the coupling coefficient are predetermined values. The controller changes the frequency according to at least one of power-transmitting status information of the power-transmitting device and power-receiving status information of the power-receiving device when the coupling coefficient changes.

Claims

1. A wireless power-supplying system comprising a power-transmitting device and a power-receiving device,

wherein the power-transmitting device includes a power-transmitting coil to which AC power of a certain frequency is input from a power supply and a controller which controls the frequency,

the power-receiving device includes a power-receiving coil which is magnetically coupled with the power-transmitting coil with a certain coupling coefficient and a power-receiving side series element connected to the power-receiving coil in series and having an imaginary impedance jZ_S2i,

the imaginary impedance is defined so that impedance when a power-receiving side is seen from the power supply is independent of the coupling coefficient when the frequency and the coupling coefficient are predetermined values, and

the controller changes the frequency according to at least one of power-transmitting status information of the power-transmitting device and power-receiving status information of the power-receiving device when the coupling coefficient changes.

2. The wireless power-supplying system according to claim 1,

wherein a fixed load is connected to the power-receiving device as a power-supply target,

the power-transmitting status information is a current I₁ flowing through the power-transmitting coil,

the power-receiving status information is a current I₂ flowing through the power-receiving coil, and

the controller changes the frequency so that Equation 1 is satisfied

3. The wireless power-supplying system according to claim 1,

wherein a fixed load is connected to the power-receiving device as a power-supply target,

the power-transmitting status information is a voltage V₁ across the power-transmitting coil,

the power-receiving status information is a voltage V₂ across the power-receiving coil, and

the controller changes the frequency so that Equation 2 is satisfied

4. The wireless power-supplying system according to claim 1,

wherein a load is connected to the power-receiving device as a power-supply target,

the power-receiving status information is load information which is one of power, a current, and a voltage input to the load, and

the controller changes the frequency so that the load information approaches a desired value.

5. The wireless power-supplying system according to claim 4,

wherein the load is a variable load.

6. The wireless power-supplying system according to claim 4,

wherein impedance of at least one of the power-transmitting coil, the power-receiving coil, and the power-receiving side series element changes.

7. The wireless power-supplying system according to claim 5,

wherein impedance of at least one of the power-transmitting coil, the power-receiving coil, and the power-receiving side series element changes.

8. The wireless power-supplying system according to claim 4,

wherein the controller further controls a magnitude of a voltage output from the power supply and changes the magnitude so that the load information approaches the desired value.

9. The wireless power-supplying system according to claim 5,

wherein the controller further controls a magnitude of a voltage output from the power supply and changes the magnitude so that the load information approaches the desired value.

10. The wireless power-supplying system according to claim 6,

wherein the controller further controls a magnitude of a voltage output from the power supply and changes the magnitude so that the load information approaches the desired value.

11. The wireless power-supplying system according to claim 7,

wherein the controller further controls a magnitude of a voltage output from the power supply and changes the magnitude so that the load information approaches the desired value.

12. The wireless power-supplying system according to claim 8,

wherein the power-transmitting status information is a phase difference of a voltage with respect to a current output from the power supply, and

the controller changes the magnitude if the phase difference is less than a threshold value due to a change in the frequency.

13. The wireless power-supplying system according to claim 9,

wherein the power-transmitting status information is a phase difference of a voltage with respect to a current output from the power supply, and

the controller changes the magnitude if the phase difference is less than a threshold value due to a change in the frequency.

14. The wireless power-supplying system according to claim 10,

wherein the power-transmitting status information is a phase difference of a voltage with respect to a current output from the power supply, and

the controller changes the magnitude if the phase difference is less than a threshold value due to a change in the frequency.

15. The wireless power-supplying system according to claim 11,

wherein the power-transmitting status information is a phase difference of a voltage with respect to a current output from the power supply, and

the controller changes the magnitude if the phase difference is less than a threshold value due to a change in the frequency.

16. The wireless power-supplying system according to claim 12,

wherein the controller further changes the frequency if the phase difference is equal to or greater than the threshold value due to a change in the magnitude.

17. The wireless power-supplying system according to claim 13,

wherein the controller further changes the frequency if the phase difference is equal to or greater than the threshold value due to a change in the magnitude.

18. The wireless power-supplying system according to claim 14,

wherein the controller further changes the frequency if the phase difference is equal to or greater than the threshold value due to a change in the magnitude.

19. The wireless power-supplying system according to claim 15,

wherein the controller further changes the frequency if the phase difference is equal to or greater than the threshold value due to a change in the magnitude.

20. The wireless power-supplying system according to claim 8,

wherein there is a maximum value of the magnitude, and

the controller changes the frequency when the magnitude reaches the maximum value due to control of the magnitude.