Wireless power transmitter, wireless power receiver and wireless power transmission method

• US 9,601,946 B2
• Filed: 12/12/2012
• Issued: 03/21/2017
• Est. Priority Date: 12/19/2011
• Status: Expired due to Fees

• Current Assignee: LG Innotek Company Limited (LG Corporation)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Bae, Su Ho
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Mourad, Rasem
• Application Number:
  US13/712,643
• Publication Number:
  US 20130154386A1
• Time in Patent Office: 1,560 Days
• Field of Search: 307/104, 320/108
• US Class Current: 1/1
• 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 through a resonance frequency band being a resonance-coupled frequency between the wireless power transmitter and the wireless power receiver, the wireless power transmitter comprising:

a transmitting unit configured to transmit a power supplied from a power source to the wireless power receiver through the resonance frequency band;

a detecting unit configured to measure an input impedance seen by the power source, and to detect a phase difference of the input impedance to obtain a state information of the wireless power receiver while transmitting the power; and

a power controlling unit configured to control the transmitting unit based on the state information in order to control an amount of the power transmitted to the wireless power receiver;

wherein the state information is created according to an output impedance of the wireless power receiver;

wherein the transmitting unit transmits an adjusted power based on the state information;

wherein the phase difference of the input impedance corresponds to a variation of the output impedance of the wireless power receiver;

wherein the wireless power transmitter recognizes information about a present charge amount of the wireless power receiver based on the phase difference, and adjusts the power corresponding to the recognized information about the present charge amount of the wireless power receiver;

wherein the phase difference in the input impedance of the wireless power transmitter is induced by the output impedance of the wireless power receiver;

wherein the state information is determined based on the phase difference of the input impedance of the wireless power transmitter; and

wherein the input impedance and the output impedance are expressed by the equation

2. The wireless power transmitter of claim 1, wherein the phase difference of the input impedance is determined using a phase difference between an input voltage and an input current of the wireless power transmitter by using the measured input impedance.

3. The wireless power transmitter of claim 2, wherein the phase difference of the input impedance is determined according to a state of a switch of the wireless power receiver.

4. The wireless power transmitter of claim 3, wherein the phase difference has a value of 0 degrees or 90 degrees.

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

a transmission induction coil configured to receive the power from the power source and

a transmission resonance coil configured to transfer 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 3, wherein the phase difference of the input impedance has a value of 0 or 1.

19. The wireless power transmitter of claim 1, wherein the state information includes information about the present charge amount of the wireless power receiver.

20. The wireless power transmitter of claim 1, wherein the state information includes information about completion of charge informing of charge completion of the wireless power receiver.

21. The wireless power transmitter of claim 1, wherein the state information includes information about a change of the charged amount of the wireless power receiver.

22. The wireless power transmitter of claim 1, further comprising a state information determining unit configured to determine the state information about the wireless power receiver based on a phase difference received from the detecting unit;

wherein the power controlling unit receives the state information from the state information determining unit.

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

a switch for varying an output impedance of the wireless power receiver to communicate state information about the wireless power receiver to the wireless power transmitter while receiving the power; and

a receiving unit configured to receive a power according to the state information from the wireless power transmitter using resonance;

wherein the switch modulates a phase difference of an input impedance of the wireless power transmitter;

wherein the state information is determined according to a state of the switch;

wherein the switch is connected in parallel to the receiving unit;

wherein the phase difference of the input impedance corresponds to a variation of the output impedance of the wireless power receiver;

wherein the phase difference represents information about a present charge amount of the wireless power receiver;

wherein the phase difference in the input impedance of the wireless power transmitter is induced by the output impedance of the wireless power receiver;

wherein the state information is determined based on the phase difference of the input impedance of the wireless power transmitter; and

wherein the input impedance and the output impedance are expressed by the equation

8. The wireless power receiver of claim 7, wherein the output impedance is an impedance seen by the receiving unit.

9. The wireless power receiver of claim 7, further comprising

a capacitor connected to the switch,

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

10. The wireless power receiver of claim 7, wherein the receiving unit comprises:

a reception resonance coil configured to receive the power from the wireless power transmitter using resonance; and

a reception induction coil configured to receive a power from the reception resonance coil through electromagnetic induction.

11. The wireless power receiver of claim 7, wherein the state information about the wireless power receiver includes the information about the present charge amount of the wireless power receiver.

17. The wireless power receiver of claim 7, wherein the state information about the power receiver includes at least one of a first information or a second information,

wherein the first information is information about completion of charge informing of charge completion, and

wherein the second information is information about a change of the charged amount of the wireless power receiver.

18. The wireless power receiver of claim 7, wherein the phase difference of the input impedance has a value of 0 degrees or 90 degrees.

12. 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 a phase difference of an input impedance of the wireless power transmitter according to a variation of the output impedance;

detecting state information of the wireless power receiver based on the phase difference; and

transmitting the power to the wireless power receiver using resonance according to the state information;

wherein the power is regulated based on the state information;

wherein the phase difference of the input impedance corresponds to a variation of the output impedance of the wireless power receiver;

wherein the wireless power transmitter recognizes information about a present charge amount of the wireless power receiver based on the base difference, and adjusts the power corresponding to the recognized information about the present charge amount of the wireless power receiver;

wherein the phase difference in the input impedance of the wireless power transmitter is induced by the output impedance of the wireless power receiver;

wherein the state information is determined based on the phase difference of the input impedance of the wireless power transmitter; and

wherein the input impedance and the output impedance are expressed by the equation

13. The method of claim 12, wherein the phase difference of the input impedance is determined using a phase difference between an input voltage and an output voltage of the wireless power transmitter.

14. The method of claim 12, wherein the output impedance is varied by using a switch and a capacitor included in the wireless power receiver.

15. The method of claim 12, wherein the state information includes at least one of a first information or a second information,

wherein the first information is information about a change of the charged amount of the wireless power receiver, and

wherein the second information is information about completion of charge information of charge completion of the wireless power receiver.

16. The method of claim 12, wherein the phase differences of the input impedance has a value of 0 degrees or 90 degrees.