WIRELESS POWER FEEDING SYSTEM

• US 20120319646A1
• Filed: 06/07/2012
• Published: 12/20/2012
• Est. Priority Date: 06/17/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KAMATA, Koichiro
• Granted Patent: US 9,099,885 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• 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 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

An object is to provide a wireless power feeding system using the resonance method, which can increase power transmission efficiency. The wireless power feeding system includes a power transmission coil electrically connected to a high-frequency power supply, a power transmission resonance coil for transmitting power by electromagnetic induction with the power transmission coil, a power reception resonance coil for exciting high-frequency power by magnetic resonance, a load coil for exciting high-frequency power by electromagnetic induction with the power reception resonance coil, a load, and a variable element. The load includes a microprocessor for controlling the impedance of the load, a battery charger, and a battery. The battery charger is configured to charge the battery with the high-frequency power excited by the load coil.

Claims

1. A wireless power feeding system comprising:

a power transmission coil;

a power transmission resonance coil for transmitting power by electromagnetic induction with the power transmission coil;

a power reception resonance coil for exciting high-frequency power by magnetic resonance;

a load coil for exciting high-frequency power by electromagnetic induction with the power reception resonance coil;

a load electrically connected to the load coil;

a variable element for controlling an amount of charging current supplied to the load; and

a microprocessor for controlling the variable element;

wherein the load includes a battery charger and a battery, the battery charger being configured to charge the battery with the high-frequency power excited by the load coil.

2. The wireless power feeding system according to claim 1, wherein the variable, element is a switch provided in the battery charger.

3. The wireless power feeding system according to claim 1, wherein the load includes a rectifier circuit electrically connected to the load coil.

4. The wireless power feeding system according to claim 1 comprising a mobile phone, a personal digital assistant, and an electric car.

5. A wireless power feeding system comprising:

a high-frequency power supply;

a power transmission coil;

a power transmission resonance coil for transmitting power by electromagnetic induction with the power transmission coil;

a first microprocessor for controlling output of the high-frequency power supply;

a power reception resonance coil for exciting high-frequency power by magnetic resonance;

a load coil for exciting high-frequency power by electromagnetic induction with the power reception resonance coil;

a load electrically connected to the load coil;

a variable element for controlling an amount of charging current supplied to the load; and

a second microprocessor,

wherein the load includes a battery charger and a battery, the battery charger being configured to charge the battery with the high-frequency power excited by the load coil, and

wherein the second microprocessor is configured to control the variable element and transmit a signal to the first microprocessor, the signal being used for controlling supply current from the high-frequency power supply.

6. The wireless power feeding system according to claim 5, wherein the variable element is a switch provided in the battery charger.

7. The wireless power feeding system according to claim 5, wherein the load includes a rectifier circuit electrically connected to the load coil.

8. The wireless power feeding system according to claim 5 comprising a mobile phone, a personal digital assistant, and an electric car.

9. A device comprising:

a power-receiving device comprising;

a power reception resonance coil for exciting high-frequency power by magnetic resonance,

a load coil for exciting high-frequency power by electromagnetic induction with the power reception resonance coil,

a load electrically connected to the load coil,

a variable element for controlling an amount of charging current supplied to the load, and

a microprocessor for controlling the variable element,

wherein the load includes a battery charger and a battery, the battery charger being configured to charge the battery with the high-frequency power excited by the load coil.

10. The device according to claim 9, wherein the variable element is a switch provided in the battery charger.

11. The device according to claim 9, wherein the load includes a rectifier circuit electrically connected to, the load coil.

12. The device according to claim 9 comprising a mobile phone, a personal digital assistant and an electric car.

13. A wireless power feeding method comprising:

placing a power-transmitting device and a power-receiving device to feed power therebetween, the power transmitting device comprising a high-frequency power supply, a power transmission coil, and a power transmission resonance coil, the power-receiving device comprising a power reception resonance coil, a load coil, a microprocessor, and a load comprising a battery charger, a variable element and a battery;

turning on the high-frequency power supply;

transmitting the power from the power transmission coil to the power transmission resonance coil through electromagnetic induction;

transmitting the power from the power transmission resonance coil to the power reception resonance coil through magnetic coupling;

transmitting the power from the power reception resonance coil to the load coil through electromagnetic induction;

charging the battery through the battery charger;

obtaining values of voltage and current applied to the load;

obtaining a power value which is a product of the values of voltage and current,

storing data of the power value in the microprocessor;

controlling the variable element to change an amount of charging current supplied to the battery by the microprocessor;

optimizing impedance of the load; and

turning off the high-frequency power supply.

14. The wireless power feeding method according to claim 13, further comprising:

converting the power into DC voltage with a rectifier circuit included in the power-receiving device, wherein the DC voltage is applied to the load.