INCREASING THE Q FACTOR OF A RESONATOR

• US 20100237707A1
• Filed: 02/26/2010
• Published: 09/23/2010
• Est. Priority Date: 07/12/2005
• Status: Abandoned Application

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Karalis, Aristeidis, Soljacic, Marin, Moffatt, Robert, Kurs, Andre B., Joannopoulos, John D., Fisher, Peter H.
• Application Number:
  US12/713,556
• Publication Number:
  US 20100237707A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B60L 2210/20 AC to AC converters
• 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 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/04 Resonant antennas
• CPC Class Codes: H02J 50/12 of the resonant type
• 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: 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 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

Described herein are embodiments of a transmitter system for transmitting wireless electrical power, that includes a source which creates an output electrical signal having a specified frequency, a coupling part, directly connected to said source, said coupling part formed of a first loop of wire which is matched for optimal power transfer to said source, and a high-Q magnetic resonator part, spaced from said coupling part such that it is not directly connected to said coupling part, but magnetically coupled to a magnetic field created by said coupling part, receiving power wirelessly from said coupling part, and said high-Q magnetic resonator part creating a magnetic field based on said power that is wirelessly received, said high-Q magnetic resonator formed of an wire coil having an inductance L, and a capacitance C, and said resonator part having an LC value which is substantially resonant with said specified frequency.

Claims

1. A transmitter system for transmitting wireless electrical power, comprising:

a source which creates an output electrical signal having a specified frequency;

a coupling part, directly connected to said source, said coupling part formed of a first loop of wire which is matched for optimal power transfer to said source; and

a high-Q magnetic resonator part, spaced from said coupling part such that it is not directly connected to said coupling part, but magnetically coupled to a magnetic field created by said coupling part, receiving power wirelessly from said coupling part, and said high-Q magnetic resonator part creating a magnetic field based on said power that is wirelessly received, said high-Q magnetic resonator formed of an wire coil having an inductance L, and a capacitance C, and said resonator part having an LC value which is substantially resonant with said specified frequency.

2. A system as in claim 1, wherein said resonator part has a quality factor greater than 100.

3. A system as in claim 1, wherein said resonator is on a material that supports said resonator part, and said material has a quality factor that changes the intrinsic Q of the resonator by less than a factor of 25.

4. A system as in claim 2, wherein said resonator part is formed with an integral capacitor.

5. A system as in claim 2, wherein said resonator part has an inductive coil loop, and a capacitor connected across a portion of said inductive coil loop.

6. A system as in claim 5, wherein said resonator part has a single turn in the coil loop.

7. A system as in claim 5, wherein said resonator has two turns in the coil loop.

8. A system as in claim 1, further comprising a receiver for the electrical power, where the receiver includes a high-Q magnetic resonator that is tuned to said specified frequency.

9. A system as in claim 8, wherein the receiver has a quality factor value that is lower than the quality factor value of the transmitter.

10. A system as in claim 8, wherein the receiver has a quality factor that is equal to or less than ¼

of the quality factor of the transmitter.

11. A system as in claim 8, wherein the receiver resonator has a size that is smaller than the size of the transmitter resonator.

12. A system as in claim 8, wherein the transmitter resonator and receiver resonator are coupled to one another to form an energy link that has a coupling coefficient proportional to the mutual inductance of the resonators.

13. A system as in claim 1, wherein said quality factor is a ratio of a resonant frequency of the resonator to a half power bandwidth of the resonator.

14. A system as in claim 1, wherein said capacitor has a Q of at least 1000.

36. A transmitter system as in claim 1, wherein said specified frequency is 13.56 MHz.

15. A receiver system for receiving wireless power, comprising:

a high-Q magnetic resonator part, configured for wirelessly receiving a magnetic field, said high-Q magnetic resonator part formed of an inductive part with an inductance L and a capacitive part with a capacitance C, collectively an LC value which are substantially resonant with a specified frequency; and

a coupling loop, spaced from said high-Q magnetic resonator part, such that said coupling loop is magnetically connected to said high-Q magnetic resonator part, said coupling part receiving a signal having said specified frequency from said high-Q magnetic resonator part, and creating a power output based thereon.

16. A system as in claim 15, further comprising an electrical circuit that receives said power output and creates output power based thereon.

17. A system as in claim 16, wherein said resonator has a quality factor greater than 100.

18. A system as in claim 16, wherein said resonator is on a material that supports said resonator part, and said material has a quality factor that changes the intrinsic Q of the resonator by less than a factor of 25.

19. A system as in claim 17, wherein said resonator part is formed with an integral capacitor.

20. A system as in claim 17, wherein said resonator part has an inductive coil loop, and a capacitor connected across a portion of said inductive coil loop.

21. A system as in claim 20, wherein said resonator part has a single turn in the coil loop.

22. A system as in claim 20, wherein said resonator has two turns in the coil loop.

23. A system as in claim 17, further comprising a transmitter for the electrical power, where the transmitter includes a high-Q magnetic resonator that is tuned to a specified frequency.

24. A system as in claim 23, further comprising a transmitter for the electrical power, where the transmitter has a quality factor value that is lower than the quality factor value of the receiver.

25. A system as in claim 23, further comprising a transmitter for the electrical power, where the transmitter has a quality factor value that is equal to or less than ¼

of the quality factor value of the receiver.

26. A system as in claim 23, wherein the transmitter resonator has a size that is smaller than the size of the receiver resonator.

27. A system as in claim 23, wherein the transmitter resonator and receiver resonator are coupled to one another in order to form an energy link that has a coupling coefficient proportional to the mutual inductance of the resonators.

28. A system as in claim 23, wherein said quality factor is a ratio of a resonant frequency of the resonator to a half power bandwidth of the resonator.

29. A system as in claim 23, wherein said capacitor has a Q of at least 1000.

66. A receiver as in claim 15, wherein said specified frequency is 13.56 MHz.

30. A method for wireless power transfer, comprising:

creating a substantially magnetic field at a specified frequency based on applied power using a first loop which includes no separate capacitor attached thereto; and

coupling a portion of the wireless power between said first loop and a second loop high-Q resonator that are associated with one another and are not electrically connected to one another, where said second loop high-Q resonator has a capacitive element that is separate from said loop, and where said second loop high-Q resonator has a resonant value at said specified frequency.

31. A method as in claim 30, wherein said first loop and second loop high-Q resonators are both transmitters.

32. A method as in claim 30, wherein said coupling comprises coupling with a coupling coefficient proportional to the mutual inductance of the loops.

33. A method for wireless power transfer, comprising:

receiving a substantially magnetic field at a specified frequency based on applied power using a first loop high-Q resonator that has a capacitor element that is physically separate from said first loop high-Q resonator, from a second high-Q loop resonator that is associated with said first loop high-Q resonator, and where said first loop high-Q resonator and said second loop high-Q resonator are associated with one another and are not electrically connected to one another, and where said second loop high-Q resonator has no separate capacitor attached thereto and where said second loop high-Q resonator has a resonant value at said specified frequency;

coupling a portion of the wirelessly-received magnetic field between said first loop high-Q resonator; and

using an output from said second loop high-Q resonator to create a power output for a load.

34. A method as in claim 33, wherein said first loop and second loop high-Q resonators are both receivers.

35. A method as in claim 33, wherein said coupling comprises coupling with a coupling coefficient proportional to the mutual inductance of the loops.

37. A transmitter system for transmitting wireless electrical power, comprising:

a source which creates an output electrical signal having a specified frequency;

a coupling part, directly connected to said source, said coupling part formed of multiple loops of wire; and

an high-Q resonator part, spaced from said coupling part such that it is not directly connected to said coupling part, but magnetically coupled to a magnetic field created by said coupling part, said high-Q resonator part receiving power wirelessly from said coupling part, and said high-Q resonator part creating a magnetic field based on said power that is wirelessly received, said antenna part formed of a wire coil having an inductance L, and a capacitor having a capacitance C, and said antenna part having an LC value which is substantially resonant with said specified frequency.

38. A transmitter system as in claim 37, wherein said multiple loops of wire are matched for optimal power transfer from the source.

39. A system as in claim 37, wherein said resonator part has a quality factor greater than 100.

40. A system as in claim 37, wherein said resonator part is formed with an integral capacitor.

41. A system as in claim 37, wherein said resonator part has an inductive coil loop, and a capacitor connected across a portion of said inductive coil loop.

42. A system as in claim 37, wherein said resonator part has a single turn in the coil loop.

43. A system as in claim 37, wherein said resonator has two turns in the coil loop.

44. A system as in claim 37, further comprising a receiver for the electrical power, where the receiver includes a high-Q magnetic resonator that is tuned to said specified frequency.

45. A system as in claim 44, wherein the receiver has a quality factor value that is lower than the quality factor value of the transmitter.

46. A system as in claim 44, wherein the receiver has a quality factor value that is equal to or less than ¼

of the quality factor value of the transmitter.

47. A system as in claim 44, wherein the receiver resonator has a size that is smaller than the size of the transmitter resonator.

48. A system as in claim 44, wherein the transmitter resonator and receiver resonator are coupled to one another to form an energy link that has a coupling coefficient proportional to the mutual inductance of the loops.

49. A receiver system for receiving wireless electrical power, comprising:

a high-Q magnetic resonator part, configured for wirelessly receiving a magnetic field, said resonator part formed of an inductive part with an inductance L and a capacitive part with a capacitance C, collectively defining an LC value which are substantially resonant with a specified frequency; and

a coupling loop, spaced from said resonator part, such that said coupling loop is magnetically connected to said resonator part, said coupling part formed of multiple turns of wire, and said coupling loop receiving a signal having said specified frequency from said resonator part, and creating a power output based thereon.

50. A system as in claim 49, further comprising an electrical circuit that receives said power output and creates output power based thereon.

51. A system as in claim 49, wherein said resonator has a quality factor greater than 100.

52. A system as in claim 49, wherein said resonator part is on a material that supports said resonator part, and said material has a quality factor that changes the intrinsic Q of the resonator by less than a factor of 25.

53. A system as in claim 49, wherein said resonator part has a single turn in the coil loop.

54. A system as in claim 49, wherein said resonator has two turns in the coil loop.

55. A system as in claim 49, further comprising a transmitter for the electrical power, where the transmitter includes a resonator that is tuned to a specified frequency.

56. A system as in claim 55, further comprising a transmitter for the electrical power, where the transmitter has a quality factor value that is lower than the quality factor value of the receiver.

57. A system as in claim 55, further comprising a transmitter for the electrical power, where the transmitter has a quality factor value that is equal to or less than ¼

of the quality factor value of the receiver.

58. A system as in claim 55, wherein the transmitter resonator has a size that is smaller than the size of the receiver resonator.

59. A method for wireless power transfer, comprising:

creating a magnetic field at a specified frequency based on applied power using a first coil formed of multiple loops of wire, which includes no separate capacitor attached thereto; and

coupling a portion of the wireless power between said first coil and a second loop high-Q magnetic resonator that are associated with one another, where said second loop resonator has a capacitor element that is separate from said loop, and where said second loop resonator has a resonant value at said first specified frequency.

60. A wireless electrical power system, comprising:

a transmitter, comprising a source which creates an output electrical signal having a specified frequency, a coupling part, directly connected to said source, said coupling part formed of a first loop of wire which is matched for optimal power transfer to said source; and

a high-Q magnetic resonator part, spaced from said coupling part such that it is not directly connected to said coupling part, but magnetically coupled to a magnetic field created by said coupling part, receiving power wirelessly from said coupling part, and said resonator part creating a magnetic field based on said power that is wirelessly received, said resonator part formed of an wire coil having an inductance L, and a capacitance C, and said resonator part having an LC value which is substantially resonant with said specified frequency; and

a receiver for the electrical power, where the receiver includes an resonator that is tuned to said specified frequency;

wherein the receiver has a quality factor value that is lower that a quality factor value of the transmitter.

61. A system as in claim 60, wherein said coupling part has multiple turns.

62. A system as in claim 60, wherein said resonator part has a single turn in the coil loop.

63. A system as in claim 60, wherein said resonator has two turns in the coil loop.

64. A system as in claim 60, wherein the receiver has a quality factor that is equal to or less than ¼

the quality factor of the transmitter.

65. A system as in claim 60, wherein the receiver resonator has a size that is smaller than a size of the transmitter resonator.