WIRELESS POWER TRANSMITTER, WIRELESS POWER RECEIVER AND WIRELESS POWER TRANSMISSION METHOD

• US 20130154386A1
• Filed: 12/12/2012
• Published: 06/20/2013
• Est. Priority Date: 12/19/2011
• Status: Active Grant

• Current Assignee: LG Innotek Company Limited (LG Corporation)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: BAE, Su Ho
• Granted Patent: US 9,601,946 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

Disclosed is a wireless power transmitter for wirelessly transmitting a power to a wireless power receiver. The wireless power transmitter includes a transmitting unit for transmitting a power supplied from a power source to the wireless power receiver using resonance, and a detecting unit for measuring an input impedance seen to the transmitting unit at the power source to detect a variation of an output impedance of the wireless power receiver by using the measured input impedance.

Claims

1. A wireless power transmitter for wirelessly transmitting a power to a wireless power receiver, the wireless power transmitter comprising:

a transmitting unit for transmitting a power supplied from a power source to the wireless power receiver using resonance; and

a detecting unit for measuring an input impedance seen to the transmitting unit at the power source to detect a variation of an output impedance of the wireless power receiver by using the measured input impedance.

2. The wireless power transmitter of claim 1, wherein the detecting unit detects a phase difference between an input voltage and an input current of the wireless power transmitter by using the measured input impedance, and detects the variation of the output impedance of the wireless power receiver by using the phase difference.

3. The wireless power transmitter of claim 1, wherein the wireless power receiver comprises:

a receiving unit for receiving the power from the transmitting unit using resonance; and

an impedance varying unit for transferring the power received in the receiving unit to a load side and for varying the output impedance, and

wherein the output impedance is an impedance seen to the impedance varying unit at the receiving unit of the wireless power receiver.

4. The wireless power transmitter of claim 2, wherein the phase difference has a value of either 0 degree or 90 degrees.

5. The wireless power transmitter of claim 1, wherein the transmitting unit comprises:

a transmission induction coil for receiving the power from the power source and

a transmission resonance coil for transferring the power received from the transmission induction coil through electromagnetic induction to the wireless power receiver using resonance.

6. The wireless power transmitter of claim 2, further comprising:

a state information determining unit for determining state information about the wireless power receiver based on the phase difference.

7. The wireless power transmitter of claim 6, further comprising:

a power controlling unit for controlling the power source according to the state information to control the power transmitted to the wireless power receiver.

8. A wireless power receiver for receiving a power from a wireless power transmitter, the wireless power receiver comprising:

an impedance varying unit for varying an output impedance of the wireless power receiver to vary an input impedance of the wireless power transmitter;

a receiving unit for receiving a power according to a variation of the output impedance from the wireless power transmitter using resonance.

9. The wireless power receiver of claim 8, wherein the output impedance is an impedance seen to the impedance varying unit at the receiving unit.

10. The wireless power receiver of claim 8, wherein the impedance varying unit comprises:

a switch; and

a capacitor connected to the switch, and

wherein the output impedance is varied by shorting or opening the switch.

11. The wireless power receiver of claim 8, wherein the receiving unit comprises:

a reception resonance coil for receiving the power from the wireless power transmitter using resonance; and

a reception induction coil for receiving a power from the reception resonance coil through electromagnetic induction.

12. The wireless power receiver of claim 8, wherein the wireless power receiver transmits state information about the wireless power receiver to the wireless power transmitter by varying the output impedance.

13. The wireless power transmitter of claim 12, wherein the state information about the wireless power receiver includes at least one of information about a present charge amount of the wireless power receiver and information about completion of charge informing of charge completion.

14. A method for transmitting a power in a wireless power system which includes a wireless power transmitter and a wireless power receiver for wirelessly receiving the power from the wireless power transmitter, the method comprising:

varying an output impedance of the wireless power receiver;

detecting an input impedance of the wireless power transmitter according to a variation of the output impedance; and

detecting the variation of the output impedance based on the input impedance.

15. The method of claim 14, wherein the detecting of the output impedance comprises:

detecting a phase difference between an input voltage and an output voltage of the wireless power transmitter based on the input impedance; and

detecting the output impedance based on the phase difference.

16. The method of claim 14, wherein the varying of the output impedance comprises:

varying the output impedance by using a switch and a capacitor included in the wireless power receiver.

17. The method of claim 14, further comprising:

determining state information about the wireless power receiver based on the variation of the output impedance.

18. The method of claim 17, further comprising:

transmitting the power to the wireless power receiver using resonance according to the state information about the wireless power receiver.

19. A recording medium having a program for executing the method for transmitting a power in the wireless power transmission system claimed in claim 14.

20. A recording medium having a program for executing the method for transmitting a power in the wireless power transmission system claimed in claim 15.