WIRELESS ENERGY TRANSFER WITH FREQUENCY HOPPING

• US 20100171368A1
• Filed: 12/31/2009
• Published: 07/08/2010
• Est. Priority Date: 09/27/2008
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Kesler, Morris P., Schatz, David A., Karalis, Aristeidis, Hall, Katherine L., Soljacic, Marin, Kurs, Andre B., Kulikowski, Konrad J., Giler, Eric R.
• Granted Patent: US 8,692,410 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: H01Q 1/248 provided with an AC/DC converting device, e.g. rectennas
• CPC Class Codes: H01Q 7/005 with variable reactance for tuning the antenna
• 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• 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 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

Described herein are improved capabilities for a source resonator having a Q-factor Q₁>100 and a characteristic size x₁ coupled to an energy source, and a second resonator having a Q-factor Q₂>100 and a characteristic size x₂ coupled to an energy drain located a distance D from the source resonator, where the source resonator and the second resonator are coupled to exchange energy wirelessly among the source resonator and the second resonator.

Claims

1. A wireless energy transfer system comprising:

a source, having at least one source magnetic resonator, each resonator having a resonant frequency;

at least one power and control circuit, coupled to a power source, and configured to energize at least one source magnetic resonator to generate an oscillating magnetic field;

a device, having at least one device magnetic resonator configured to capture said oscillating magnetic field, each device magnetic resonator having a resonant frequency;

wherein magnetic energy transferred by the source to the device is converted into electrical energy by one or more device resonators and wherein frequency of said oscillating magnetic field of said source is varied in time.

2. The system of claim 1, wherein said oscillating magnetic field generated by the source is substantially at the resonant frequency of the energized source magnetic resonator.

3. The system of claim 1, wherein the frequency of said oscillating magnetic field is varied to prevent power transfer to unauthorized devices.

4. The system of claim 1, wherein the frequency of said oscillating magnetic field is varied in time to a random value within a predetermined frequency range.

5. The system of claim 1, wherein the frequency of said oscillating magnetic field is varied in time in a predetermined sequence.

6. The system of claim 1, wherein the frequency of said oscillating magnetic field is varied in time to pseudo-random values within a predetermined frequency range.

7. The system of claim 6, wherein the frequency of said oscillating magnetic field is varied at least ten times per second.

8. The system of claim 6, wherein the frequency of said oscillating magnetic field is varied at least ten times per minute.

9. The system of claim 6, wherein the frequency of said oscillating magnetic field is varied at least ten times per hour.

10. The system of claim 6, wherein the frequency of said oscillating magnetic field is varied between a set of discrete frequencies.

11. The system of claim 10, wherein the frequency of said oscillating magnetic field is varied between a set of three or more discrete frequencies.

12. The system of claim 10, wherein the frequency of said oscillating magnetic field is varied between a set of 100 or more discrete frequencies.

13. The system of claim 6, wherein the frequency of said oscillating magnetic field is varied to any frequency in a predetermined frequency range.

14. The system of claim 13, wherein the predetermined frequency range is between 1 kHz and 100 MHz.

15. The system of claim 2, wherein said resonators are coupled to adjustable electrical components.

16. The system of claim 15, wherein the adjustable electrical components include capacitors.

17. The system of claim 15, wherein the adjustable electrical components include inductors.

18. The system of claim 15, wherein the resonant frequency of said resonators is varied by tuning at least one value of said adjustable electrical components.

19. The system of claim 15, wherein said magnetic resonators are high-Q magnetic resonators.

20. The system of claim 19, wherein the quality factor of said magnetic resonators is at least 100.

21. The system of claim 19, wherein the quality factor of said magnetic resonators is at least 100 for more than one frequency.

22. The system of claim 5, wherein the resonant frequency of at least one device magnetic resonator is varied in the same said predetermined sequence as the said oscillating magnetic field.

23. The system of claim 6, wherein the resonant frequency of at least one device magnetic resonator is varied to the same pseudo-random values within said predetermined frequency range as the said oscillating magnetic field.

24. The system of claim 2, wherein different said source magnetic resonators are energized depending on the frequency of said oscillating magnetic field.

25. The system of claim 2, wherein the frequency of said oscillating magnetic field is changed to reduce interference with other power transfer systems.

26. The system of claim 2, wherein the frequency of said oscillating magnetic field is changed to multiplex power to multiple device resonators tuned to different resonant frequencies.

27. A wireless energy transfer source comprising:

at least one source magnetic resonator, each resonator having a resonant frequency;

at least one power and control circuit, coupled to a power source, and configured to energize at least one source magnetic resonator to generate an oscillating magnetic field;

wherein the frequency of said oscillating magnetic field of said source is varied in time.

28. The source of claim 27, wherein said oscillating magnetic field generated is substantially at the resonant frequency of the energized source magnetic resonator.

29. The source of claim 28, wherein the frequency of said oscillating magnetic field is varied in a predetermined sequence.

30. The source of claim 28, wherein the frequency of said oscillating magnetic field is varied to a pseudo-random value within a predetermined frequency range.

31. The source of claim 27, wherein the quality factor of said magnetic resonators is at least 100.

32. The source of claim 29, wherein the resonant frequency of the energized source magnetic resonator may be varied using at least one tunable electrical component.

33. The source of claim 29, wherein the quality factor of said magnetic resonators is maintained above 100 as the source frequency is changed.

34. A wireless energy transfer device comprising:

at least one device magnetic resonator configured to capture an oscillating magnetic field, each resonator having a resonant frequency;

at least one tunable electrical component coupled to at least one said magnetic resonator

wherein the resonant frequency of at least one said magnetic resonator is varied in time.

35. The device of claim 34, wherein said tunable electrical components comprise an adjustable capacitor.

36. The device of claim 34, wherein said tunable electrical components comprise an adjustable inductor.

37. The device of claim 34, wherein the resonant frequency of said magnetic resonator is varied in a predetermined sequence.

38. The device of claim 34, wherein the resonant frequency of said magnetic resonator is varied to a pseudo-random value.

39. The device of claim 34, wherein the quality factor of said magnetic resonators is at least 100.

40. A method of wireless power transfer comprising:

providing a source, having a source magnetic resonator;

energizing said source magnetic resonator to generate an oscillating magnetic field at substantially a single frequency;

providing a device, having a device magnetic resonator configured to capture said oscillating magnetic field;

tuning said source and device resonators to another resonant frequency after a period of operation using tunable electrical components.

41. The method of claim 40, wherein the period of operation is less than one second.

42. The method of claim 40, wherein the period of operation is less than one minute.

43. The method of claim 40, wherein said tunable electrical components comprise an adjustable capacitor.

44. The method of claim 40, wherein said tunable electrical components comprise an adjustable inductor.

45. The method of claim 40, wherein during tuning to another resonant frequency, the said frequency is varied in a predetermined sequence.

46. The method of claim 40, wherein during tuning to another resonant frequency, the said frequency is varied in a pseudo-random sequence.