Wireless power apparatus and methods

Patent metadata

Field	Value
Publication number	US-9774086-B2
Application number	US-1806908-A
Country	US
Kind code	B2
Filing date	Jan 22, 2008
Priority date	Mar 2, 2007
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

Wireless energy transfer system. Antennas are maintained at resonance with High Q. Techniques of maintaining the high-Q resonance matching are disclosed.

First claim

What is claimed is:

1. A method of transferring power, comprising:
transmitting power from a transmitter to a receiver, wherein the transmitter comprises
a coupling loop driven by a source, and
a resonating circuit magnetically coupled to the coupling loop, and spaced apart from the coupling loop, the resonating circuit comprising
an inductive loop antenna, and
a capacitor electrically coupled to the inductive loop antenna, the inductive loop antenna spaced apart from the coupling loop, the coupling loop configured to inductively excite the resonating circuit, and the coupling loop further configured to provide matching between the source and the resonating circuit based at least in part on the spacing between the coupling loop and the resonating circuit, the resonating circuit configured to generate a magnetic field based on being excited by the coupling loop to transmit power sufficient to charge or power a load of the receiver;
receiving signaling information from the receiver, the signaling information indicating a level of received power as determined by the receiver;
comparing the level of the received power to a level of the transmitted power; and
tuning the resonant frequency of the transmitter based at least in part on the comparison of the level of the received power to the level of the transmitted power.

2. The method as in claim 1 , wherein said tuning comprises matching impedances between the transmitter and the receiver.

3. The method as in claim 2 , wherein the capacitor comprises an adjustable capacitor, and wherein said tuning comprises electrically adjusting a capacitance value of the adjustable capacitor in the transmitter.

4. The method as in claim 3 , wherein said tuning comprises adjusting a distance between plates in the adjustable capacitor.

5. The method as in claim 3 , wherein said adjustable capacitor comprises an electrically adjustable capacitor, and said tuning comprises automatically tuning.

6. The method as in claim 5 , wherein said electrically adjustable capacitor comprises a varactor diode.

7. The method as in claim 3 , further comprising a fixed value capacitor in addition to said adjustable capacitor.

8. The method as in claim 7 , further comprising a variable capacitor that has 8-12% of a capacitance value of the fixed value capacitor.

9. The method as in claim 1 , further comprising detecting an object in response to detecting a reduction in matching between the transmitter and the receiver.

10. The method as in claim 1 , wherein the capacitor comprises an electrically-adjustable capacitor, and wherein said tuning comprises electrically adjusting a capacitance value of the electrically-adjustable capacitor in the transmitter to a desired value.

11. The method as in claim 1 , wherein said transmitting comprises storing energy in a near field of the transmitter and inducing said energy into the receiver.

12. The method as in claim 1 , wherein inductive loop antenna has a Q of at least 1000.

13. The method as in claim 1 , wherein the inductive loop antenna is a magnetic antenna which is tuned to within 10% of its resonant value.

14. The method as in claim 2 , wherein the transmitter includes at least one additional capacitor therein, and further comprising sizing the capacitor and the additional capacitor to withstand at least 2 KV of reactive voltage.

15. A wireless power transmitter, comprising:
a coupling loop driven by a source;
a resonating circuit magnetically coupled to the coupling loop, and spaced apart from the coupling loop, the resonating circuit comprising an inductive loop antenna and a capacitor electrically coupled to the inductive loop antenna, the inductive loop antenna spaced apart from the coupling loop, the coupling loop configured to inductively excite the resonating circuit, and the coupling loop further configured to provide matching between the source and the resonating circuit based at least in part on the spacing between the coupling loop and the resonating circuit, the resonating circuit configured to generate a magnetic field based on being excited by the coupling loop to transmit power sufficient to charge or power a load of a receiver;
a receiving signaling information circuit configured to receive signaling information from the receiver, the signaling information indicating a level of received power as determined by the receiver, and the receiving signaling information circuit further configured to compare the level of the received power to a level of the transmitted power; and
a tuning circuit configured to tune the resonant frequency of the inductive loop antenna based at least in part on the comparison of the level of the received power to the level of the transmitted power.

16. The transmitter as in claim 15 , wherein said tuning circuit comprises an adjustable capacitor.

17. The transmitter as in claim 16 , wherein said adjustable capacitor comprises a capacitor with plates whose relative distance can be adjusted.

18. The transmitter as in claim 15 , wherein said tuning circuit comprises an electrically adjustable capacitor.

19. The transmitter as in claim 18 , wherein said tuning circuit comprises a varactor diode.

20. The transmitter as in claim 18 , further comprising a fixed value capacitor in addition to said adjustable capacitor.

21. The transmitter as in claim 20 , wherein the adjustable capacitor is a variable capacitor that has 8-12% of a capacitance value of the fixed value capacitor.

22. The transmitter as in claim 15 , further comprising a detection circuit configured to detect, during operation, interference caused by an object reducing the matching between the inductive loop antenna and a receiving antenna, the detection circuit further configured to terminate power transmission until the reduction of matching is terminated.

23. The transmitter as in claim 15 , wherein the capacitor comprises an electrically-adjustable capacitor connected to the inductive loop antenna and wherein said tuning circuit electrically adjusts a capacitance value of the electrically-adjustable capacitor to improve said matching.

24. The transmitter as in claim 15 , wherein said inductive loop antenna has a Q of at least 1000.

25. The transmitter as in claim 15 , wherein said inductive loop antenna is a magnetic antenna which is tuned to within 10% of its resonant value.

26. The transmitter as in claim 15 , wherein at least part of said inductive loop antenna is electrically decoupled from said power transmitter.

27. A system for transferring power, the system comprising:
means for transmitting power to a receiver, wherein the transmitting means comprises a coupling loop driven by a source; and
a resonating circuit magnetically coupled to the coupling loop and spaced apart from the coupling loop, the resonating circuit comprising
an inductive loop antenna; and
a capacitor electrically coupled to the inductive loop antenna, the inductive loop antenna spaced apart from the coupling loop, the coupling loop configured to inductively excite the resonating circuit and the coupling loop further configured to provide matching between the source and the resonating circuit based at least in part on the spacing between the coupling loop and the resonating circuit, the resonating circuit configured to generate a magnetic field based on being excited by the coupling loop to transmit power sufficient to charge or power a

Assignees

• Cook Nigel P
• Meier Paul
• Sieber Lukas
• Secall Marc
• Widmer Hanspeter
• Qualcomm Inc

Inventors

• Cook Nigel P
• Meier Paul
• Sieber Lukas
• Secall Marc
• Widmer Hanspeter

Classifications

• H02J50/90

  involving detection or optimisation of position, e.g. alignment · CPC title

• H02J50/12

  of the resonant type · CPC title

• H01Q7/005 Primary

  with variable reactance for tuning the antenna · CPC title

• H02J50/10

  using inductive coupling · CPC title

• H02J17/00

  Electricity · mapped topic