Method and device for impedance matching using isolated resonator in wireless power transmission system

• US 10,141,793 B2
• Filed: 04/21/2016
• Issued: 11/27/2018
• Est. Priority Date: 10/21/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Seungkeun, Kwon, Ui Kun, Kim, Sang Joon
• Primary Examiner(s): Shin, Jeffrey
• Application Number:
  US15/134,525
• Publication Number:
  US 20160233725A1
• Time in Patent Office: 950 Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

A wireless power transmitter includes a source resonator configured to transmit wireless power by resonating with a target resonator, a first power supply configured to supply power to the source resonator, a first switch configured to turn ON/OFF a connection between of the source resonator to the first power supply, and a controller configured to match an impedance of the source resonator by estimating a distance between the source resonator and the target resonator.

Claims

1. A wireless power transmitter comprising:

a source resonator configured to transmit wireless power by resonating with a target resonator;

a first power supply configured to supply power to the source resonator;

a first switch configured to turn ON/OFF a connection of the source resonator to the first power supply, wherein the source resonator is isolated in response to the first switch turning OFF; and

a controller configured to match an impedance of the source resonator by estimating a distance between the source resonator and the target resonator.

2. The wireless power transmitter of claim 1, wherein the controller is further configured to control the wireless power transmitter to operate in a power transmission mode and an impedance matching mode.

3. The wireless power transmitter of claim 2, wherein the controller is further configured to control a supply of power to the source resonator by controlling the first switch in the impedance matching mode.

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

a second power supply configured to supply power to the source resonator; and

a second switch configured to turn ON/OFF a connection of the source resonator to the second power supply;

wherein the controller is further configured to control a supply of power to the source resonator by controlling the second switch in the impedance matching mode.

5. The wireless power transmitter of claim 2, wherein the controller comprises:

an envelope detector configured to detect an envelope of the wireless power transmitted by the source resonator in the impedance matching mode;

a distance estimator configured to estimate a distance between the source resonator and the target resonator based on the envelope; and

an impedance matcher configured to match the impedance of the source resonator based on the estimated distance.

6. The wireless power transmitter of claim 5, wherein the distance estimator is further configured to estimate a coupling coefficient or a mutual inductance between the source resonator and the target resonator based on a time difference between at least two points of the envelope.

7. The wireless power transmitter of claim 6, wherein the at least two points comprise at least two of:

at least one peak point at which an amplitude of the envelope reaches a peak;

at least one minimum point at which the amplitude of the envelope reaches a minimum; and

a start point at which the source resonator and the target resonator start the resonating in the impedance matching mode.

8. The wireless power transmitter of claim 2, wherein the controller is further configured to control the wireless power transmitter to operate in the impedance matching mode based on predetermined intervals or a predetermined power transmission efficiency.

9. The wireless power transmitter of claim 2, wherein the controller is further configured to end the impedance matching mode in response to the resonating of the target resonator and the source resonator being suspended in the impedance matching mode.

10. The wireless power transmitter of claim 2, wherein the controller is further configured to match the impedance of the source resonator in the impedance matching mode based on a resonance frequency between the source resonator and the target resonator in the power transmission mode.

11. A wireless power receiver comprising:

a target resonator configured to receive wireless power by resonating with a source resonator;

a load configured to receive power from the target resonator; and

a controller configured to match an impedance of the target resonator by estimating a distance between the source resonator and the target resonator,

wherein the controller is further configured to estimate the distance based on an envelope of the wireless power received by the target resonator.

12. The wireless power receiver of claim 11, wherein the controller is further configured to control the wireless power receiver to operate in a power transmission mode and an impedance matching mode.

13. The wireless power receiver of claim 12, wherein the controller is further configured to control the wireless power receiver to operate in the impedance matching mode in response to a change in the wireless power received by the target resonator.

14. The wireless power receiver of claim 12, further comprising a switch configured to turn ON/OFF a connection of the target resonator to the load;

wherein the controller is further configured to turn OFF the switch in the impedance matching mode.

15. The wireless power receiver of claim 12, wherein the controller comprises:

an envelope detector configured to detect the envelope of the wireless power received by the target resonator in the impedance matching mode;

a distance estimator configured to estimate the distance between the source resonator and the target resonator based on the envelope; and

an impedance matcher configured to match an impedance of the target resonator based on the estimated distance.

16. The wireless power receiver of claim 15, wherein the distance estimator is further configured to estimate a coupling coefficient or a mutual inductance between the source resonator and the target resonator based on a time difference between at least two points of the envelope.

17. The wireless power receiver of claim 16, wherein the at least two points comprise at least two of:

at least one peak point at which an amplitude of the envelope reaches a peak;

at least one minimum point at which the amplitude of the envelope reaches a minimum; and

a start point at which the source resonator and the target resonator start the resonating in the impedance matching mode.

18. A wireless power transmitter comprising:

a source resonator configured to transmit wireless power by resonating with a target resonator in response to power supplied to the source resonator;

a switch configured to interrupt the power from being supplied to the source resonator; and

a controller configured to match an impedance of the source resonator based on an envelope of the wireless power transmitted by the source resonator in response to the switch interrupting the power from being supplied to the source resonator.

19. The wireless power transmitter of claim 18, wherein the controller is further configured to control the switch not to interrupt the power from being supplied to the source resonator during a power transmission mode, control the switch to interrupt the power from being supplied to the source resonator during an impedance matching mode, and match the impedance of the source resonator during the impedance matching mode.

20. The wireless power transmitter of claim 19, wherein the controller is further configured to control the switch to interrupt the power from being supplied to the source resonator a plurality of times during the impedance matching mode.

21. The wireless transmitter of claim 18, wherein the controller is further configured to estimate a coupling coefficient or a mutual inductance between the source resonator and the target resonator based on a time difference between two points of the envelope, and match the impedance of the source resonator based on the estimated coupling coefficient or mutual inductance.

22. The wireless transmitter of claim 21, wherein the time difference changes as a distance between the source resonator and the target resonator changes.

23. The wireless transmitter of claim 21, further comprising a lookup table (LUT) storing a relationship between the coupling coefficient or the mutual inductance and the time difference;

wherein controller is further configured to estimate the coupling coefficient or the mutual inductance by looking up the time difference in the LUT, and reading out a coupling coefficient or a mutual inductance corresponding to the time difference from the LUT.

24. A wireless power receiver comprising:

a target resonator configured to receive wireless power by resonating with a source resonator; and

a controller configured to match an impedance of the target resonator based on an envelope of the wireless power received by the target resonator, control a switch not to interrupt the power from being received by a load during a power transmission mode, control a switch to interrupt the power from being received by the load during an impedance matching mode, and match the impedance of the target resonator during the impedance matching mode.

25. The wireless transmitter of claim 24, wherein the controller is further configured to estimate a coupling coefficient or a mutual inductance between the source resonator and the target resonator based on a time difference between two points of the envelope, and match the impedance of the target resonator based on the estimated coupling coefficient or mutual inductance.

26. The wireless transmitter of claim 25, wherein the time difference changes as a distance between the source resonator and the target resonator changes.

27. The wireless transmitter of claim 25, further comprising a lookup table (LUT) storing a relationship between the coupling coefficient or the mutual inductance and the time difference;

wherein controller is further configured to estimate the coupling coefficient or the mutual inductance by looking up the time difference in the LUT, and reading out a coupling coefficient or a mutual inductance corresponding to the time difference from the LUT.