Method and system of wireless power transfer foreign object detection

• US 10,250,081 B2
• Filed: 08/15/2016
• Issued: 04/02/2019
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Triune Systems, LLC (Semtech Corporation)
• Original Assignee: Triune Systems, LLC (Semtech Corporation)
• Inventors: Teggatz, Ross E., Atrash, Amer, Chen, Wayne, Knight, Jonathan
• Primary Examiner(s): Le, Son
• Assistant Examiner(s): Zakaria, Akm
• Application Number:
  US15/237,288
• Publication Number:
  US 20170012478A1
• Time in Patent Office: 960 Days
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A wireless power transfer foreign object detector having, at least one secondary receiver coil, an adjustable load electrically coupled to the at least one secondary receiver coil, and at least one temperature sensor providing at least one temperature detection signal, wherein the at least one temperature sensor responsive to at least one thermal state of the at least one secondary receiver coil, and wherein foreign object detection is based at least in part upon the at least one temperature detection signal.

Claims

1. A method of wireless power transfer foreign object detection comprising:

measuring at least one tuned state of at least one secondary receiver coil;

detuning an adjustable load of the at least one secondary receiver coil from at least one resonant frequency;

measuring at least one detuned state of the at least one secondary receiver coil; and

determining at least one foreign object based at least in part upon the at least one tuned state and the at least one detuned state.

2. The method of wireless power transfer foreign object detection according to claim 1 further comprising timing a predetermined period after the tuned state measurement.

3. The method of wireless power transfer foreign object detection according to claim 1 further comprising reducing at least one power signal to the at least one secondary receiver coil based at least in part upon the at least one foreign object determination.

4. A wireless power transfer foreign object detector comprising:

at least one primary transmitter coil;

one or more satellite transmitter coils adjacent to the at least one primary transmitter coil; and

wherein foreign object detection is based at least in part upon at least one characteristic of an electrical coupling of at least one of the one or more satellite transmitter coils.

5. The wireless power transfer foreign object detector according to claim 4 further comprising at least one secondary receiver coil electrically responsive to at least one of the at least one primary transmitter coil and at least one of the one or more satellite transmitter coils.

6. The wireless power transfer foreign object detector according to claim 4 further comprising at least one secondary receiver coil.

7. The wireless power transfer foreign object detector according to claim 4 further comprising:

at least one secondary receiver coil; and

a plurality of satellite receiver coils adjacent to the at least one secondary receiver coil.

8. The wireless power transfer foreign object detector according to claim 4 wherein the at least one characteristic of the electrical coupling of the at least two of the one or more satellite transmitter coils is a coupling coefficient.

9. The wireless power transfer foreign object detector according to claim 4 wherein the at least one characteristic of the electrical coupling of the at least two of the one or more satellite transmitter coils is power.

10. The wireless power transfer foreign object detector according to claim 4 wherein the at least one characteristic of the electrical coupling of the at least two of the one or more satellite transmitter coils is a temperature.

11. A method of wireless power transfer foreign object detection comprising:

measuring at least one characteristic of an electrical coupling between at least one primary transmitter coil and at least one satellite transmitter coil;

measuring at least one characteristic of an electrical coupling between the at least one primary transmitter coil and at least one secondary receiver coil; and

determining at least one foreign object based at least in part upon the measured at least one characteristic of the electrical coupling between the at least one primary transmitter coil and the at least one satellite transmitter coil and between the at least one primary transmitter coil and the at least one secondary receiver coil.

12. The method of wireless power transfer foreign object detection according to claim 11 further comprising measuring at least one characteristic of an electrical coupling between the at least one secondary receiver coil and at least one satellite receiver coil.

13. The method of wireless power transfer foreign object detection according to claim 12 further comprising determining at least one foreign object based at least in part upon the measured at least one characteristic of the electrical coupling between the at least one secondary receiver coil and at least one satellite receiver coil.

14. The method of wireless power transfer foreign object detection according to claim 11 further comprising reducing a power transmitted signal to the at least one primary transmitter coil based at least in part upon the determined at least one foreign object.

15. The method of wireless power transfer foreign object detection according to claim 11 further comprising generating a fault flag based at least in part upon the determined at least one foreign object.

16. A method of wireless power transfer foreign object detection comprising:

setting at least one primary transmitter coil to a primary transmitter voltage state;

setting at least one secondary receiver coil to a secondary receiver voltage state;

measuring a capacitive coupling between the at least one primary transmitter coil and the at least one secondary receiver coil; and

determining at least one foreign object based at least in part upon the measured capacitive coupling between the at least one primary transmitter coil and the at least one secondary receiver coil.

17. The method of wireless power transfer foreign object detection according to claim 16 further comprising setting at least one satellite transmitter coil to a satellite transmitter voltage state.

18. The method of wireless power transfer foreign object detection according to claim 17 further comprising measuring at least one characteristic of capacitive coupling between the at least one satellite transmitter coil and the at least one secondary receiver coil.

19. The method of wireless power transfer foreign object detection according to claim 18 further comprising determining at least one foreign object based at least in part upon the measured at least one characteristic of capacitive coupling between the at least one satellite transmitter coil and the at least one secondary receiver coil.

20. The method of wireless power transfer foreign object detection according to claim 16 further comprising setting at least one satellite receiver coil to a satellite receiver voltage state.