Wireless energy transfer to a moving device between high-Q resonators

• US 8,791,599 B2
• Filed: 12/30/2009
• Issued: 07/29/2014
• Est. Priority Date: 07/12/2005
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Joannopoulos, John D., Karalis, Aristeidis, Soljacic, Marin
• Primary Examiner(s): Fleming, Fritz M
• Application Number:
  US12/649,635
• Publication Number:
  US 20100102640A1
• Time in Patent Office: 1,672 Days
• Field of Search: 307/104
• US Class Current: 307/104
• 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: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01Q 9/04 Resonant antennas
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• 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 embodiments of a first resonator with a quality factor, Q1, greater than 100, coupled to an energy source, generating an oscillating near field region, and a second resonator, with a quality factor, Q2, greater than 100, optionally coupled to an energy drain, and moving freely within the near field region of the first resonator. The first resonator and the second resonator may be coupled to transfer electromagnetic energy from said first resonator to said second resonator as the second resonator moves freely within the near field region.

Claims

1. A system, comprising:

a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁) greater than 100, and configured to be coupled to an energy source to generate an oscillating near field region; and

a second resonator having a resonant frequency ω

₂ and an intrinsic loss rate Γ

₂, and capable of storing electromagnetic energy with an intrinsic quality factor Q₂=ω

₂/(2Γ

₂) greater than 100, and configured to move freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are configured to be coupled to transfer electromagnetic energy from said first resonator to said second resonator when the first resonator is coupled to the energy source as the second resonator moves freely within the near field region, and

further comprising the energy source configured to be coupled to the first resonator and an energy drain configured to be coupled to the second resonator to provide useful power to the energy drain, and wherein the energy source is configured to provide energy to the first resonator at a rate that varies with a rate of wireless energy transfer κ

between the first resonator and the second resonator.

2. The system of claim 1, wherein near field of the near field region is a magnetic field.

3. The system of claim 1, wherein near field of the near field region is an electromagnetic field.

4. The system of claim 1, wherein each intrinsic loss rate comprises a resistive component and a radiative component.

5. The system of claim 1, wherein the energy source is configured to provide energy to the first resonator at a rate that substantially minimizes the energy stored in the first resonator and the second resonator.

6. The system of claim 1, wherein the energy source is configured to provide energy to the first resonator at a rate that substantially maximizes a ratio of the useful power to lost power from the energy source to the energy drain.

7. A method, comprising:

providing a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁) greater than 100, coupled to an energy source, generating an oscillating near field region; and

providing a second resonator having a resonant frequency ω

₂ and an intrinsic loss rate Γ

₂, and capable of storing electromagnetic energy with an intrinsic quality factor Q₂=∩

₂/(2Γ

₂), greater than 100, and moving freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are coupled to transfer electromagnetic energy from said first resonator to said second resonator as the second resonator moves freely within the near field region,

wherein an energy drain is coupled to the second resonator to provide useful power to the energy drain, and the method further comprises providing energy to the first resonator at a rate that varies with a rate of wireless energy transfer κ

between the first resonator and the second resonator.

8. The method of claim 7, wherein near field of the near field region is a magnetic field.

9. The method of claim 7, wherein near field of the near field region is an electromagnetic field.

10. The method of claim 7, wherein each intrinsic loss rate comprises a resistive component and a radiative component.

11. The method of claim 7, wherein the energy source provides energy to the first resonator at a rate that substantially minimizes the energy stored in the first resonator and the second resonator.

12. The method of claim 7, wherein the energy source provides energy to the first resonator at a rate that substantially maximizes a ratio of the useful power to lost power from the energy source to the energy drain.

13. A system, comprising:

a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), and configured to be coupled to an energy source to generate a near field region comprising an oscillating magnetic field; and

a second resonator having a resonant frequency ω

₂ and an intrinsic loss rate Γ

₂, and capable of storing electromagnetic energy with an intrinsic quality factor Q₂=ω

₂/(2Γ

₂), and configured to move freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are configured to be coupled to wirelessly transfer electromagnetic energy from said first resonator to said second resonator when the first resonator is coupled to the energy source as the second resonator moves freely within the near field region,

wherein √

{square root over (Q₁Q₂)}>

100, and

further comprising the energy source configured to be coupled to the first resonator and an energy drain configured to be coupled to the second resonator to provide useful power to the energy drain, and wherein the energy source is configured to provide energy to the first resonator at a rate that varies with a rate of wireless energy transfer κ

between the first resonator and the second resonator.

14. The system of claim 13, where Q₁>

100 and Q₂>

100.

15. The system of claim 13, further comprising an energy drain coupled to the second resonator.

16. The system of claim 15, wherein the energy drain comprises a robot, vehicle, computer, cell phone, or a portable electronic device.

17. The system of claim 13, further comprising a third resonator, optionally coupled to an energy drain, located at a variable distance from the first resonator, and wherein the first resonator and the third resonator are coupled to wirelessly transfer electromagnetic energy from the first resonator to the third resonator.

18. The system of claim 13, further comprising a third resonator, optionally coupled to an external power supply, located at a variable distance from the second resonator, and wherein the third resonator and the second resonator are coupled to wirelessly transfer electromagnetic energy from the third resonator to the second resonator.

19. The system of claim 13, wherein at least one of the resonators is a tunable resonator.

20. The system of claim 13, wherein the energy transfer in the near-field region occurs over a range of distances that includes 5 cm.

21. The system of claim 13, wherein the energy transfer in the near-field region occurs over a range of distances that includes 10 cm.

22. The system of claim 13, wherein the energy transfer in the near-field region occurs over a range of distances that includes 30 cm.

23. The system of claim 13, wherein the efficiency of the wireless energy transfer is at least 20% over a range of distances in the near-field region.

24. The system of claim 13, further comprising a feedback mechanism coupled to at least one of the resonators to correct for detuning.

25. The system of claim 13, wherein the energy source is configured to provide energy to the first resonator at a rate that substantially minimizes the energy stored in the first resonator and the second resonator.

26. The system of claim 13, wherein the energy source is configured to provide energy to the first resonator at a rate that substantially maximizes a ratio of the useful power to lost power from the energy source to the energy drain.

27. The system of claim 13, where Q₁>

200 and Q₂>

200.

28. The system of claim 13, wherein each intrinsic loss rate comprises a resistive component and a radiative component.

29. A system, comprising:

a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), and configured to be coupled to an energy source to generate a near field region comprising an oscillating magnetic field; and

a second resonator having a resonant frequency ω

₂ and an intrinsic loss rate Γ

₂, and capable of storing electromagnetic energy with an intrinsic quality factor Q₂=ω

₂/(2Γ

₂), and configured to move freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are configured to be coupled to wirelessly transfer electromagnetic energy from said first resonator to said second resonator when the first resonator is coupled to the energy source as the second resonator moves freely within the near field region,

wherein √

{square root over (Q₁Q₂)}>

100, and

further comprising the energy drain coupled to the second resonator, and wherein the power supply and energy drain are configured to be driven to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ

between the first resonator and the second resonator.

30. A system, comprising:

a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), and configured to be coupled to an energy source to generate a near field region comprising an oscillating magnetic field; and

a second resonator having a resonant frequency ω

₂ and an intrinsic loss rate Γ

₂ and capable of storing electromagnetic energy with an intrinsic quality factor Q₂=ω

₂/(2Γ

₂), and configured to move freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are configured to be coupled to wirelessly transfer electromagnetic energy from said first resonator to said second resonator when the first resonator is coupled to the energy source as the second resonator moves freely within the near field region,

wherein √

{square root over (Q₁Q₂)}>

100, and

wherein the first resonator and second resonator are configured to be adjustably tuned to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ

between the first resonator and the second resonator.

31. A method, comprising:

providing a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), coupled to an energy source, generating a near field region comprising an oscillating magnetic field; and

providing a second resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), and moving freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are coupled to wirelessly transfer electromagnetic energy from said first resonator to said second resonator as the second resonator moves freely within the near field region,

wherein √

{square root over (Q₁Q₂)}>

100, and

wherein an energy drain is coupled to the second resonator to provide useful power to the energy drain, and the method further comprises providing energy to the first resonator at a rate that varies with a rate of wireless energy transfer κ

between the first resonator and the second resonator.

32. The method of claim 31, where Q₁>

100 and Q₂>

100.

33. The method of claim 31, wherein an energy drain is coupled to the second resonator.

34. The method of claim 33, wherein the energy drain comprises a robot, vehicle, computer, cell phone, or a portable electronic device.

35. The method of claim 31, wherein a third resonator is optionally coupled to an energy drain and is located at a variable distance from the first resonator, and further comprising wirelessly transferring electromagnetic energy from the first resonator to the third resonator.

36. The method of claim 31, wherein a third resonator is optionally coupled to an external power supply and is located at a variable distance from the second resonator, and further comprising wirelessly transferring electromagnetic energy from the third resonator to the second resonator.

37. The method system of claim 31, wherein at least one of the resonators is a tunable resonator.

38. The method of claim 31, wherein the energy transfer in the near-field region occurs over a range of distances that includes 5 cm.

39. The method of claim 31, wherein the energy transfer in the near-field region occurs over a range of distances that includes 10 cm.

40. The method of claim 31, wherein the energy transfer in the near-field region occurs over a range of distances that includes 30 cm.

41. The method of claim 31, wherein the efficiency of the wireless energy transfer is at least 20% over a range of distances in the near-field region.

42. The method of claim 31, wherein a feedback mechanism is coupled to at least one of the resonators to correct for detuning.

43. The method of claim 31, wherein the energy source provides energy to the first resonator at a rate that substantially minimizes the energy stored in the first resonator and the second resonator.

44. The method of claim 31, wherein the energy source provides energy to the first resonator at a rate that substantially maximizes a ratio of the useful power to lost power from the energy source to the energy drain.

45. The method of claim 31, where Q₁>

200 and Q₂>

200.

46. The method of claim 31, wherein each intrinsic loss rate comprises a resistive component and a radiative component.

47. A method, comprising:

providing a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), coupled to an energy source, generating a near field region comprising an oscillating magnetic field; and

providing a second resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), and moving freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are coupled to wirelessly transfer electromagnetic energy from said first resonator to said second resonator as the second resonator moves freely within the near field region,

wherein √

{square root over (Q₁Q₂)}>

100, and

wherein the energy drain is coupled to the second resonator, and wherein the power supply and energy drain are driven to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ

between the first resonator and the second resonator.

48. A method, comprising:

providing a first resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), coupled to an energy source, generating a near field region comprising an oscillating magnetic field; and

providing a second resonator having a resonant frequency ω

₁ and an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), and moving freely within the near field region of the first resonator,

wherein the first resonator and the second resonator are coupled to wirelessly transfer electromagnetic energy from said first resonator to said second resonator as the second resonator moves freely within the near field region,

wherein √

{square root over (Q₁Q₂)}>

100, and

wherein the first resonator and second resonator are adjustably tuned to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ

between the first resonator and the second resonator.