METHOD AND SYSTEM OF WIRELESS POWER TRANSFER FOREIGN OBJECT DETECTION

• US 20130181724A1
• Filed: 01/17/2013
• Published: 07/18/2013
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Triune Systems, LLC (Semtech Corporation)
• Original Assignee: Triune Ip, LLC (Semtech Corporation)
• Inventors: Teggatz, Ross E., Atrash, Amer, Chen, Wayne, Knight, Jonathan
• Granted Patent: US 9,417,199 B2
• Time in Patent Office: Days
• US Class Current: 324/629
• 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 wireless power transfer foreign object detector comprising:

at least one secondary receiver coil;

an adjustable load electrically coupled to said at least one secondary receiver coil; and

at least one temperature sensor providing at least one temperature detection signal, said at least one temperature sensor responsive to at least one thermal state of said at least one secondary receiver coil; and

wherein foreign object detection is based at least in part upon said at least one temperature detection signal.

2. The wireless power transfer foreign object detector according to claim 1 further comprising a timer electrically coupled to said adjustable load.

3. The wireless power transfer foreign object detector according to claim 1 wherein said adjustable load is complex.

4. The wireless power transfer foreign object detector according to claim 1 wherein said at least one temperature sensor comprises at least one of a thermocouple, a thermopile, a thermo-diode, a thermo-transistor and an optical thermal sensor.

5. A method of wireless power transfer foreign object detection comprising the steps of:

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

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

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

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

6. The method of wireless power transfer foreign object detection according to claim 5 further comprising the step of:

timing a predetermined soak period after said tuned temperature measurement.

7. The method of wireless power transfer foreign object detection according to claim 5 further comprising the step of:

reducing at least one power signal to said at least one secondary receiver based at least in part upon said at least one foreign object determination.

8. A wireless power transfer foreign object detector comprising:

at least one primary transmitter coil;

at least one secondary receiver coil responsive to said at least one primary transmitter coil;

an adjustable complex load electrically coupled to said at least one secondary receiver coil; and

at least one temperature sensor responsive to at least one thermal state of said at least one secondary receiver coil; and

wherein a foreign object detection is based at least in part upon said at least one thermal state of said at least one secondary receiver coil.

9. The wireless power transfer foreign object detector according to claim 8 wherein said at last one transmitted power signal transmits a substantially constant power.

10. The wireless power transfer foreign object detector according to claim 8 wherein said at last one transmitted power signal at a predetermined rate of decrease.

11. The wireless power transfer foreign object detector according to claim 8 wherein said at last one transmitted power signal transmits at a predetermined rate of increase.

12. A wireless power transfer foreign object detector comprising:

at least one primary transmitter coil;

a plurality of satellite transmitter coils adjacent to said 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 two of said plurality of satellite transmitter coils.

13. The wireless power transfer foreign object detector according to claim 12 further comprising:

at least one secondary receiver coil electrically responsive to at least one of said at least one primary transmitter coil and at least one of said plurality of satellite transmitter coils.

14. The wireless power transfer foreign object detector according to claim 12 further comprising:

at least one secondary receiver coil;

a plurality of satellite receiver coils adjacent to said at least one secondary receiver coil; and

wherein foreign object detection is based at least in part upon at least one characteristic of an electrical coupling of said plurality of satellite receiver coils to said plurality of said satellite transmitter coils.

15. The wireless power transfer foreign object detector according to claim 12 wherein said at least one characteristic of said electrical coupling of said at least two of said plurality of satellite transmitter coils is a coupling coefficient.

16. The wireless power transfer foreign object detector according to claim 12 wherein said at least one characteristic of said electrical coupling of said at least two of said plurality of satellite transmitter coils is power.

17. The wireless power transfer foreign object detector according to claim 12 wherein said at least one characteristic of said electrical coupling of said at least two of said plurality of satellite transmitter coils is a temperature.

18. A wireless power transfer foreign object detector comprising:

at least one secondary receiver coil;

a plurality of satellite receiver coils adjacent to said at least one secondary receiver coil; and

wherein foreign object detection is based at least in part upon at least one characteristic of an electrical coupling of at least two of said plurality of satellite receiver coils.

19. The wireless power transfer foreign object detector according to claim 18 further comprising:

at least one primary transmitter coil electrically responsive to at least one of said at least one secondary receiver coil and at least one of said plurality of satellite receiver coils.

20. A method of wireless power transfer foreign object detection comprising the steps of:

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 said 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 said measured at least one characteristic of said electrical coupling between said at least one primary transmitter coil and said at least one satellite transmitter coil and between said at least one primary transmitter coil and said at least one secondary receiver coil.

21. The method of wireless power transfer foreign object detection according to claim 20 further comprising the steps of:

measuring at least one characteristic of an electrical coupling between said at least one secondary receiver coil and at least one satellite receiver coil; and

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

22. The method of wireless power transfer foreign object detection according to claim 20 further comprising the steps of:

reducing a power transmitted signal to said at least one primary transmitter coil based at least in part upon said determined at least one foreign object.

23. The method of wireless power transfer foreign object detection according to claim 20 further comprising the steps of:

generating a fault flag based at least in part upon said determined at least one foreign object.

24. A method of wireless power transfer foreign object detection comprising the steps of:

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 said at least one primary transmitter coil and said at least one secondary receiver coil; and

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

25. The method of wireless power transfer foreign object detection according to claim 24 further comprising the steps of:

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

measuring at least one characteristic of capacitive coupling between said at least one satellite transmitter coil and said at least one secondary receiver coil; and

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

26. The method of wireless power transfer foreign object detection according to claim 24 further comprising the steps of:

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

measuring at least one characteristic of capacitive coupling between said at least one satellite receiver coil and said at least one primary transmitter coil; and

determining at least one foreign object based at least in part upon said measured at least one characteristic of capacitive coupling between said at least one satellite transmitter coil and said at least one primary transmitter coil.

27. A method of wireless power transfer foreign object detection comprising the steps of:

setting at least one receiver power transmitted from at least one secondary receiver coil;

measuring at least one receiver temperature state of said at least one secondary receiver coil; and

determining at least one foreign object based at least in part upon at least one of said measured at least one receiver temperature state.

28. The method of wireless power transfer foreign object detection of claim 27 further comprising the steps of:

setting at least one transmitter power transmitted from at least one primary transmitter coil;

measuring at least one transmitter temperature state of said at least one primary transmitter coil; and

determining at least one foreign object based at least in part upon at least one of said measured at least one transmitter temperature state.

29. A wireless power transfer foreign object detector comprising:

at least one inner primary transmitter coil;

at least one outer primary transmitter coil, said outer primary transmitter coil adjacent to said at least one inner primary transmitter coil; and

at least one temperature sensor providing at least one transmitter temperature detection signal, said at least one temperature sensor responsive to at least one thermal state of said at least one inner primary transmitter coil and at least one outer primary transmitter coil; and

wherein foreign object detection is based at least in part upon said at least one transmitter temperature detection signal.

30. A wireless power transfer foreign object detector comprising:

at least one inner secondary receiver coil;

at least one outer secondary receiver coil, said outer secondary receiver coil adjacent to said at least one secondary receiver coil; and

at least one temperature sensor providing at least one receiver temperature detection signal, said at least one temperature sensor responsive to at least one thermal state of said at least one inner secondary receiver coil and at least one outer secondary receiver coil; and

wherein foreign object detection is based at least in part upon said at least one receiver temperature detection signal.

31. A wireless power transfer foreign object detector comprising:

a plurality of mobile ferrites;

at least one optical detector optically responsive to said plurality of mobile ferrites, said at least one optical detector providing an optical detection signal; and

wherein foreign object detection is based at least in part upon said optical detection signal.

32. A wireless power transfer foreign object detector comprising:

a plurality of mobile ferrites;

at least one magnetic detector responsive to said plurality of mobile ferrites, said at least one magnetic detector providing a magnetic detection signal, wherein foreign object detection is based at least in part upon said magnetic detection signal; and

at least one mobile ferrite sweeper that locationally directs at least one of said plurality of mobile ferrites based at least in part upon said foreign object detection signal.

33. The wireless power transfer foreign object detector according to claim 32 wherein said at least one magnetic detector responsive to at least one of a primary transmitter coil and a secondary receiver coil.

34. The wireless power transfer foreign object detector according to claim 33 wherein said at least one mobile ferrite sweeper responsive to at least one of said primary transmitter coil and said secondary receiver coil.