METHOD FOR DETECTING FOREIGN MATERIAL, AND APPARATUS AND SYSTEM THEREFOR

• US 20190319495A1
• Filed: 06/25/2019
• Published: 10/17/2019
• Est. Priority Date: 08/23/2016
• Status: Active Grant

• Current Assignee: LG Innotek Company Limited (LG Corporation)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: PARK, Jae Hee
• Granted Patent: US 10,862,348 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• 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 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A method of controlling a wireless power transmitter is discussed. The method includes transmitting a power signal having a predetermined strength; measuring a quality factor and a peak frequency of a coil of the wireless power transmitter using the power signal; receiving reference values including a reference quality factor and a reference peak frequency of a wireless power receiver; determining whether or not a foreign object is present in a charging area of the wireless power transmitter based on a comparison of the reference quality factor with the measured quality factor and a comparison of the reference peak frequency with the measured peak frequency; transmitting response signals indicating a result of the determination; and determining whether to continue or stop a wireless charging procedure based on the response signals.

Claims

1. A method of controlling a wireless power transmitter, the method comprising:

transmitting a power signal having a predetermined strength;

measuring a quality factor and a peak frequency of a coil of the wireless power transmitter using the power signal;

receiving reference values including a reference quality factor and a reference peak frequency of a wireless power receiver;

determining whether or not a foreign object is present in a charging area of the wireless power transmitter based on a comparison of the reference quality factor with the measured quality factor and a comparison of the reference peak frequency with the measured peak frequency;

transmitting response signals indicating a result of the determination; and

determining whether to continue or stop a wireless charging procedure based on the response signals.

2. The method according to claim 1, wherein the response signals include a first response signal and a second response signal, and

wherein if at least one of the first and second response signals includes a negative response signal indicating the foreign object is present in the charging area, determining to stop the wireless charging procedure.

3. The method according to claim 2, wherein if the first and second response signals include a positive response signal indicating the foreign object is not present in the charging area in response to all of the reference values, determining to continue the wireless charging procedure.

4. The method according to claim 1, wherein the reference quality factor is received first from the wireless power receiver in a first foreign object detection status packet and then the reference peak frequency is received from the wireless power receiver in a second foreign object detection status packet, or

wherein the reference peak frequency is received first in the first foreign object detection status packet from the wireless power receiver and then the reference quality factor is received in the second foreign object detection status packet from the wireless power receiver.

5. The method according to claim 4, wherein the first and second foreign object detection status packets further include mode information identifying whether the reference peak frequency and the reference quality factor are included in the first and second foreign object detection status packets.

6. The method according to claim 1, wherein the peak frequency of the power signal is shifted when the foreign object is present in the charging area.

7. The method according to claim 1, wherein the reference peak frequency includes a frequency corresponding to a Q-factor in an operating frequency range of a reference wireless power transmitter.

8. The method according to claim 3, further comprising:

determining a threshold frequency based on a preset tolerance in addition to the reference peak frequency.

9. The method according to claim 8, wherein the response signals include the negative response signal when the measured peak frequency is greater than the threshold frequency, and

wherein the response signals include the positive response signal indicating when the measured peak frequency is equal or less than the threshold frequency.

10. The method according to claim 3, further comprising:

determining a threshold quality factor based on a preset tolerance in addition to the reference quality factor.

11. The method according to claim 10, wherein the response signals include the negative response signal when the measured quality factor is equal or less than the threshold quality factor, and

wherein the response signals include the positive response signal when the measured quality factor is greater than the threshold quality factor.

12. A wireless power transmitter, comprising:

a power transmission unit including at least one coil configured to transmit a power signal having a predetermined strength; and

a controller configured to;

measure a quality factor and a peak frequency of the at least one coil using the power signal,

receive reference values including a reference quality factor and a reference peak frequency of a wireless power receiver,

determine whether or not a foreign object is present in a charging area of the wireless power transmitter based on a comparison of the reference quality factor with the measured quality factor and a comparison of the reference peak frequency with the measured peak frequency,

control the power transmission unit to transmit response signals indicating a result of the determination, and

determine whether to continue or stop a wireless charging procedure based on the response signals.

13. The wireless power transmitter according to claim 12, wherein the response signals include a first response signal and a second response signal, and

wherein if at least one of the first and second response signals includes a negative response signal indicating the foreign object is present in the charging area, the controller determines to stop the wireless charging procedure due to the foreign object.

14. The wireless power transmitter according to claim 13, wherein if the first and second response signals include a positive response indicating the foreign object is not present in the charging area in response to all of the reference values, the controller determines to continue the wireless charging procedure.

15. The wireless power transmitter according to claim 12, wherein the reference quality factor is received first from the wireless power receiver in a first foreign object detection status packet and then the reference peak frequency is received from the wireless power receiver in a second foreign object detection status packet, or

wherein the reference peak frequency is received first in the first foreign object detection status packet from the wireless power receiver and then the reference quality factor is received in the second foreign object detection status packet from the wireless power receiver.

16. The wireless power transmitter according to claim 14, wherein the controller is further configured to:

determine a threshold frequency based on a preset tolerance in addition to the reference peak frequency.

17. The wireless power transmitter according to claim 16, wherein the response signals include the negative response signal indicating the foreign object is present in the charging area when the measured peak frequency is greater than the threshold frequency, and

wherein the response signals include the positive response indicating the foreign object is not present in the charging area when the measured peak frequency is equal or less than the threshold frequency.

18. A wireless power receiver, comprising:

a wireless communication unit configured to communicate with a wireless power transmitter;

a memory configured to store reference values including a reference quality factor and a reference peak frequency of the wireless power receiver; and

a controller configured to;

generate first and second foreign object status packets including mode information indicating whether or not information on the reference quality factor and the reference peak frequency are included in the first and second foreign object status packets,

transmit the first and second foreign object status packets to the wireless power transmitter, and

receive foreign object detection indicators indicating whether or not a foreign object is present in a charging area of the wireless power transmitter.

19. The wireless power receiver according to claim 18, wherein the controller is further configured to:

request end of power transfer in response to at least one of the foreign object detection indicators when the at least one of the foreign object detection indicators includes a negative response signal.

20. The wireless power receiver according to claim 18, wherein the controller is further configured to:

request to proceed a subsequent phase in response to at least one of the foreign object detection indicators when the at least one of the foreign object detection indicators includes a negative response signal.

21. The wireless power receiver according to claim 18, wherein if the foreign object detection indicators include a negative response signal indicating the foreign object is present in the charging area, the controller requests an end of a charging procedure.

22. The wireless power receiver according to claim 21, wherein if the foreign object detection indicators include a positive response signal indicating the foreign object is not present in the charging area, the charging procedure is not stopped due to the foreign object.

23. The wireless power receiver according to claim 18, wherein the first foreign object detection status packet is transmitted first and then the second foreign object detection status packet is transmitted, or

wherein the second foreign object detection status packet is transmitted first and then the first foreign object detection status packet is transmitted.

24. The wireless power receiver according to claim 18, wherein the foreign object detection indicators are determined based on the first and second foreign object status packets.

25. The wireless power receiver according to claim 22, wherein the foreign object detection indicators include the negative response signal when a measured peak frequency of a power signal transmitted by the wireless power transmitter is greater than a threshold frequency, and

wherein the foreign object detection indicators include the positive response signal when the measured peak frequency of the power signal transmitted by the wireless power transmitter is equal to or less than the threshold frequency.

26. The wireless power receiver according to claim 25, wherein the threshold frequency is determined by the wireless power transmitter based on the reference peak frequency.

27. The wireless power receiver according to claim 22, wherein the foreign object detection indicators include the negative response signal when a measured quality factor of a power signal transmitted by the wireless power transmitter is equal to or less than a threshold quality factor, and

wherein the foreign object detection indicators include the positive response signal when the measured quality factor of the power signal transmitted by the wireless power transmitter is greater than the threshold quality factor.

28. The wireless power receiver according to claim 27, wherein the threshold quality factor is determined by the wireless power transmitter based on the reference quality factor.

29. The wireless power receiver according to claim 18, wherein a peak frequency of a power signal transmitted by the wireless power transmitter is shifted from the reference peak frequency when the foreign object is present in the charging area.

30. The wireless power receiver according to claim 18, wherein the reference peak frequency includes a frequency corresponding to a Q-factor in an operating frequency range of a reference wireless power transmitter.