WIRELESS POWER APPARATUS AND METHODS

• US 20080211320A1
• Filed: 01/22/2008
• Published: 09/04/2008
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: Nigel Power LLC (Qualcomm, Inc.)
• Inventors: Widmer, Hanspeter, Sieber, Lukas, Cook, Nigel P., Secall, Marc, Meier, Paul
• Granted Patent: US 9,774,086 B2
• Time in Patent Office: Days
• US Class Current: 307/149
• CPC Class Codes: H01Q 7/005 with variable reactance for tuning the antenna
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• 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

Abstract

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

Claims

1. A method, comprising:

inducing power into a near field magnetic field of a transmitting antenna; and

operating the transmitting antenna along with a receiving antenna, to couple the power magnetically to a receiving antenna that has at least one characteristic that is matched to the transmitting antenna; and

tuning at least one of said antennas to improve a matching therebetween.

2. A method as in claim 1, wherein said matching comprises matching impedances between said antennas.

3. A method as in claim 2, wherein said tuning comprises using an adjustable capacitor in the at least one of said antennas and electrically adjusting a capacitance value of the adjustable capacitor to a desired value.

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

5. A method as in claim 4, wherein said adjusting comprises using screws made of a non-electrical material.

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

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

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

9. A method as in claim 8, wherein said variable capacitor has 10% of a capacitance value of the fixed value capacitor.

10. A method as in claim 2, further comprising detecting a temporary situation that reduces matching between the transmitter and receiver, and carrying out at least one operation responsive to said detecting.

11. A method as in claim 10, wherein said detecting is carried out at the transmitter.

12. A method as in claim 11, wherein said least one operation comprises terminating power transmission until the temporary situation is terminated.

13. A method as in claim 2 wherein said tuning comprises using an electrically adjustable capacitor in the at least one antenna and electrically adjusting a capacitance value of the electrically-adjustable capacitor to a desired value and wherein said at least one operation comprises changing a value of said adjustable capacitor.

14. A method as in claim 1, wherein said transmitter and said receiver are both formed of antennas made of circular shaped loops of electrically conductive material.

15. A method as in claim 1, wherein said operating comprises storing energy in and near field of the transmitting antenna and inducing said energy into the receiving antenna.

16. A method as in claim 1, wherein each of said antennas have a Q of at least 1000.

17. A method as in claim 1, wherein each of said antennas are magnetic antennas which are tuned to within 10% of their resonant values.

18. A method as in claim 2, wherein said antennas include capacitors therein, and further comprising sizing said capacitors to withstand at least 2 KV of reactive voltage.

19. A wireless power transmitter, comprising:

a power transmitter, that produces power to be transmitted wirelessly over a magnetic link; and

an inductive loop antenna part, having at least one capacitive part connected to said inductive loop part, wherein said capacitive part is sized to withstand at least 2 KV of reactive voltage.

20. A transmitter as in claim 19, further comprising a receiver with a receiving antenna that is matched to the transmitting antenna.

21. A transmitter as in claim 19, further comprising a tuning part that allows tuning said antenna.

22. A transmitter as in claim 21, wherein said tuning part comprises an adjustable capacitor.

23. A transmitter as in claim 22, wherein said adjustable capacitor comprises a capacitor with plates whose distance can be adjusted.

24. A transmitter as in claim 23, wherein said capacitor has screws made of a non-electrical material.

25. A transmitter as in claim 21, wherein said tuning part comprises an electrically adjustable capacitor.

26. A transmitter as in claim 25, wherein said tuning part comprises a varactor diode.

27. A transmitter as in claim 25, further comprising a fixed value capacitor in addition to said adjustable capacitor.

28. A transmitter as in claim 27, wherein said variable capacitor that has 10% of a capacitance value of the fixed value capacitor.

29. A transmitter as in claim 20, further comprising a part that detects a reduction of matching between the transmitter and receiver, and carries out at least one operation responsive to the detecting.

30. A transmitter as in claim 29, wherein said device terminates power transmission until the temporary situation is terminated.

31. A transmitter as in claim 29, further comprising an adjustable capacitor in at least one antenna and said device electrically adjusts a capacitance value of the electrically-adjustable capacitor to a desired value to change a value of said adjustable capacitor to improve said matching.

32. A transmitter as in claim 19, wherein said antenna is made of circular shaped loop of electrically conductive material.

33. A transmitter as in claim 19, wherein said antenna has a Q of at least 1000.

34. A transmitter as in claim 19, wherein said antenna is a magnetic antenna which is tuned to within 10% of its resonant value.

35. A transmitter as in claim 19, wherein said antenna has a first part, connected to the power transmitter, and forming a coupling loop, and a second part, electrically unconnected to said coupling loop, into which power is electrically induced.

36. A transmitter as in claim 19, wherein at least part of said antenna is electrically decoupled from said power transmitter.

37. A transmitter as in claim 19, wherein at least part of said antenna is coated with an anti corrosion material.

38. A wireless power receiver, comprising:

an inductive loop antenna part, having at least one capacitive part connected to said inductive loop part, wherein said capacitive part is sized to withstand at least 2 KV of reactive voltage; and

a power receiver, coupled to receive power from said inductive loop antenna part, that has been transmitted wirelessly over a magnetic link.

39. A receiver as in claim 38, wherein said inductive loop antenna part forms a receiving antenna, and further comprising a transmitter with a transmitting antenna that is matched to the receiving antenna.

40. A receiver as in claim 38, further comprising a tuning part that allows tuning said antenna.

41. A receiver as in claim 40, wherein said tuning part comprises an adjustable capacitor.

42. A receiver as in claim 41, wherein said adjustable capacitor comprises a capacitor with plates whose distance can be adjusted.

43. A receiver as in claim 42, wherein said capacitor has screws made of a non-electrical material.

44. A receiver as in claim 40, wherein said tuning part comprises an electrically adjustable capacitor.

45. A receiver as in claim 44, wherein said tuning part comprises a varactor diode.

46. A receiver as in claim 44, further comprising a fixed value capacitor in addition to said adjustable capacitor.

47. A receiver as in claim 46, wherein said variable capacitor that has 10% of a capacitance value of the fixed value capacitor.

48. A receiver as in claim 39, further comprising a part that detects a reduction of matching between the receiver and transmitter, and carries out at least one operation responsive to the detecting.

49. A receiver as in claim 48, wherein said device terminates power transmission until the temporary situation is terminated.

50. A receiver as in claim 48, further comprising an adjustable capacitor in at least one antenna and said device electrically adjusts a capacitance value of the electrically-adjustable capacitor to a desired value to change a value of said adjustable capacitor to improve said matching.

52. A receiver as in claim 38, wherein said antenna is made of a circular shaped loop of electrically conductive material.

53. A receiver as in claim 38, wherein said antenna has a Q of at least 1000.

54. A receiver as in claim 38, wherein said antenna is a magnetic antenna which is tuned to within 10% of its resonant value.

55. A receiver as in claim 38, wherein at least part of said antenna is coated with an anti corrosion material.

56. A wireless power transmitter, comprising:

a power transmitter connection, that receives energy to be transmitted wirelessly over a magnetic link;

a first coupling antenna part, electrically connected to receive said energy; and

a second antenna part, electrically disconnected from said first coupling part and from said power transmitter connection, and operating to transmit, magnetically, said energy.

57. A transmitter as in claim 56, wherein at least one of said antenna parts includes an inductive loop antenna part, having at least one capacitive part connected to said inductive loop part, wherein said capacitive part is sized to withstand at least 2 KV of reactive voltage.

58. A transmitter as in claim 56, further comprising a tuning part that allows tuning said antenna.

59. A transmitter as in claim 58, wherein said tuning part comprises an adjustable capacitor.

60. A transmitter as in claim 56, wherein said adjustable capacitor comprises a capacitor with plates whose distance can be adjusted.

61. A transmitter as in claim 58, wherein said tuning part comprises an electrically adjustable capacitor.

62. A transmitter as in claim 61, wherein said tuning part comprises a varactor diode.

63. A transmitter as in claim 61, further comprising a fixed value capacitor in addition to said adjustable capacitor.

64. A transmitter as in claim 63, wherein said variable capacitor that has 10% of a capacitance value of the fixed value capacitor.

65. A method, comprising:

transmitting power from a transmitting antenna to a receiving antenna;

automatically detecting a detuning event that detunes a relationship between said transmitting antenna and receiving antenna; and

responsive to said detecting, automatically taking an action to change a characteristic of said transmitting.

66. A method as in claim 65, wherein said action comprises terminating device power transmission during a time of the detuning event.

67. A transmitter as in claim 65, wherein said action comprises electronically tuning one of said antennas to a different resonance value.

68. A wireless power transmitter, comprising:

a power transmitter connection, that receives energy to be transmitted wirelessly over a magnetic link;

at least one antenna part formed of a single loop of conductive material; and

a capacitor part, having a value to match an L and C value of the antenna to a frequency of said power transmitter.

69. A transmitter as in claim 68, wherein said antenna includes a first coupling antenna part, electrically connected to receive said energy;

and

a second antenna part, electrically disconnected from said first coupling part and from said power transmitter connection, and operating to transmit, magnetically, said energy.

70. A transmitter as in claim 68, wherein said capacitor part is sized to withstand 2 KV of reactive voltage.

71. A method, comprising:

magnetically transmitting power from a transmitting antenna to a receiving antenna, where each of said antennas has a Q value for a specified frequency, greater than 1000; and

tuning said antennas to maintain resonance at said specified frequency.

72. A method comprising:

forming a radiated magnetic field with energy therein using a transmitting antenna with a Q value greater than 1000;

extracting energy from the radiated field of the transmitting antenna, at a receiving antenna location that is unconnected to said transmitting antenna by any wires; and

using said energy in an electronic device that is unconnected to said transmitting antenna by any wires.

73. A method as in claim 72, further comprising adaptively tuning circuit one of said antennas.

74. A method as in claim 73 wherein said adaptive tuning is carried out automatically by an electric circuit associated with at least one of said antennas.

75. A method as in claim 72, further comprising matching a resistance of a receiving antenna to the load resistance.

76. A method as in claim 72, further comprising shielding at least one of said antennas against external influences to resonance.

77. A method as in claim 76, wherein said shield is against stray capacitance.

78. An apparatus comprising:

a receiving antenna, operative to extract energy from a radiated field at a receiving antenna location that is unconnected to any transmitting antenna by any wires; and

a power system, using said energy in an electronic device that is unconnected to said transmitting antenna by any wires.

79. An apparatus as in claim 78, further comprising an adaptive tuning circuit, changing a tuning value of one of said antennas.

80. An apparatus as in claim 79 wherein said adaptive tuning circuit is an automatic tuning circuit associated with at least one of said antennas.

81. An apparatus as in claim 78, further comprising a matching circuit that matches a resistance of a receiving antenna to the load resistance.

82. An apparatus as in claim 78, further comprising a shield that shields at least one of said antennas against external influences to resonance.

83. An apparatus as in claim 82, wherein said shield is a slotted shield.