POWER FEEDING DEVICE AND WIRELESS POWER FEEDING SYSTEM

• US 20120187771A1
• Filed: 01/18/2012
• Published: 07/26/2012
• Est. Priority Date: 01/20/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KAMATA, Koichiro, SATO, Misako, OKANO, Shinya, MAEDA, Shuhei
• Granted Patent: US 9,024,482 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• 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: H03C 1/36 by means of semiconductor device having at least three electrodes H03C1/34, H03C1/50, H03C1/52, H03C1/62 take precedence
• CPC Class Codes: H03D 1/02 Details
• CPC Class Codes: H03H 7/38 Impedance-matching networks

Abstract

A resonant power feeding system that can provide high power transmission efficiency between a power feeding device and a power reception device without dynamically controlling the oscillation frequency in accordance with the distance between the power feeding device and the power reception device. High power transmission efficiency between the power feeding device and the power reception device is obtained by addition of a structure for adjusting the matching condition to both the power reception device and the power feeding device. Specifically, a transmission-reception circuit and a matching circuit are provided in both the power reception device and the power feeding device, and wireless signals for adjusting the matching circuit are transmitted and received through a resonant coil. Thus, the power feeding device can efficiently supply power to the power reception device without adjusting the oscillation frequency.

Claims

1. A wireless power feeding device comprising:

a high frequency power source;

a resonant coil configured to transmit power to a power reception device;

a coil electromagnetically coupled to the resonant coil;

a transmission-reception circuit configured to produce a first wireless signal and demodulate a second wireless signal from the power reception device received by the coil through the resonant coil;

a matching circuit configured to match impedance between the high frequency power source and the coil; and

a control circuit configured to control the matching circuit in accordance with a power value detected by the power reception device and included in the second wireless signal, and to generate a data of the first wireless signal superimposed on an alternating-current signal output from the high frequency power source.

2. The wireless power feeding device according to claim 1, wherein the transmission-reception circuit includes a modulation circuit configured to modulate the alternating-current signal output from the high frequency power source.

3. The wireless power feeding device according to claim 1, wherein the matching circuit includes a variable capacitor whose capacitance is controlled by the control circuit.

4. The wireless power feeding device according to claim 1, wherein the matching circuit includes a variable coil whose inductance is controlled by the control circuit.

5. A wireless power reception device comprising:

a rectifier circuit;

a resonant coil configured to receive power from a power feeding device;

a coil electromagnetically coupled to the resonant coil;

a transmission-reception circuit configured to produce a first wireless signal and demodulate a second wireless signal from the power feeding device received by the coil through the resonant coil;

a matching circuit configured to match impedance between the rectifier circuit and the coil; and

a control circuit configured to control the matching circuit in accordance with the second wireless signal, and to generate a data of the first wireless signal superimposed on an alternating-current signal output from the power feeding device.

6. The wireless power reception device according to claim 5, wherein the transmission-reception circuit includes a load modulator configured to apply load modulation to the alternating-current signal output from the power feeding device.

7. The wireless power reception device according to claim 5, wherein the matching circuit includes a variable capacitor whose capacitance is controlled by the control circuit.

8. The wireless power reception device according to claim 5, wherein the matching circuit includes a variable coil whose inductance is controlled by the control circuit.

9. A wireless power feeding system comprising:

a power feeding device comprising;

a high frequency power source;

a first resonant coil;

a first coil electromagnetically coupled to the first resonant coil;

a first transmission-reception circuit configured to produce a first wireless signal and demodulate a second wireless signal;

a first matching circuit configured to match impedance between the high frequency power source and the first coil; and

a first control circuit configured to control the first matching circuit, and

a power reception device comprising;

a second resonant coil receiving the first wireless signal from the power feeding device by resonating with the first resonant coil;

a second coil electromagnetically coupled to the second resonant coil;

a rectifier circuit;

a received power detection circuit;

a second transmission-reception circuit configured to produce the second wireless signal and demodulate the first wireless signal;

a second matching circuit configured to match impedance between the rectifier circuit and the second coil; and

a second control circuit configured to control the second matching circuit,

wherein the first control circuit is configured to control the first matching circuit in accordance with a power value detected by the received power detection circuit and included in the second wireless signal, and

wherein the second control circuit is configured to control the second matching circuit in accordance with a data of the first wireless signal.

10. The wireless power feeding system according to claim 9, wherein the first transmission-reception circuit includes a modulation circuit configured to modulate an alternating-current signal output from the high frequency power source.

11. The wireless power feeding system according to claim 9, wherein the second transmission-reception circuit includes a load modulator configured to apply load modulation to an alternating-current signal output from the power feeding device.

12. The wireless power feeding system according to claim 9, wherein a configuration of the first matching circuit is the same as a configuration of the second matching circuit.

13. The wireless power feeding system according to claim 12, wherein the first matching circuit includes a variable capacitor whose capacitance is controlled by the first control circuit, and the second matching circuit includes a variable capacitor whose capacitance is controlled by the second control circuit.

14. The wireless power feeding system according to claim 12, wherein the first matching circuit includes a variable coil whose inductance is controlled by the first control circuit, and the second matching circuit includes a variable coil whose inductance is controlled by the second control circuit.