Wireless non-radiative energy transfer
The electromagnetic energy transfer device includes a first resonator structure receiving energy from an external power supply. The first resonator structure has a first Q-factor. A second resonator structure is positioned distal from the first resonator structure, and supplies useful working power to an external load. The second resonator structure has a second Q-factor. The distance between the two resonators can be larger than the characteristic size of each resonator. Non-radiative energy transfer between the first resonator structure and the second resonator structure is mediated through coupling of their resonant-field evanescent tails.
1. A system for wirelessly providing power to a load, the system comprising:
a first electromagnetic resonator configured to be coupled to a power supply, the first resonator having a characteristic size L 1 , a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 );
a second electromagnetic resonator configured to be coupled to the load, the second resonator having a characteristic size L 2 , a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ),
wherein the first and second resonators are configured to be wirelessly coupled to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ, and
wherein the resonators satisfy κ/√{square root over (Γ 1 Γ 2 )}>1 for at least some distances D between the first and second resonators satisfying D/L 2 >1.
2. The system of claim 1 , wherein the distances D satisfy D/L 2 >2.
3. The system of claim 1 , wherein the distances D satisfy D/L 2 >3.
4. The system of claim 1 , wherein the distances D satisfy D/L 2 >5.
5. The system of claim 1 , wherein the resonators further satisfy κ/√{square root over (Γ 1 Γ 2 )}>1 for the distances D/L 2 >1 and different relative orientations of the first and second resonators.
6. The system of claim 1 , wherein Q 1 >100.
7. The system of claim 1 , wherein Q 2 >100.
8. The system of claim 1 , wherein (√{square root over (Q 1 Q 2 )})>100.
9. The system of claim 1 , wherein the first and second resonators are movable relative to one another.
10. The system of claim 1 , further comprising the power supply coupled to the first resonator and the load coupled to the second resonator.
11. The system of claim 1 , wherein the first resonator provides at least 10 W of wireless power to the second resonator.
12. The system of claim 1 , wherein the efficiency of the wireless energy transfer from the first resonator to the second resonator is at least 20%.
13. The system of claim 12 , wherein the distances D include 10 cm.
14. The system of claim 1 , wherein the distances D include 5 cm.
15. The system of claim 1 , wherein the distances D include 30 cm.
16. The system of claim 1 , wherein the resonant frequencies f 1 =ω 1 /2π and f 2 =ω 2 /2π are each at least 5 MHz.
17. The system of claim 1 , wherein said first resonator comprises a capacitive element and an inductive element.
18. The system of claim 1 , wherein said second resonator comprises a capacitive element and an inductive element.
19. The system of claim 1 , further comprising a feedback mechanism coupled to at least one of the resonators to correct for frequency detuning.
20. The system of claim 11 , wherein the power supply and load are driven to increase the ratio of useful-to-lost power for the wireless energy transfer rate κ.
21. The system of claim 11 , wherein the second resonator and the load are part of a portable electronic device.
22. The system of claim 21 , wherein the portable electronic device is a cell phone, a computer, a robot, or a vehicle.
23. The system of claim 1 , wherein the characteristic size of at least one of the resonators is at least 1 cm.
24. The system of claim 1 , wherein the characteristic size of at least one of the resonators is at least 30 cm.
25. The system of claim 1 , wherein the characteristic sizes of the first and second resonators are different from one another.
26. The system of claim 1 , wherein at least one of the resonators is tunable.
27. The system of claim 1 , wherein the resonators satisfy κ/√{square root over (Γ 1 Γ 2 )}>2 for the distances D.
28. The system of claim 1 , wherein the resonators satisfy κ/√{square root over (Γ 1 Γ 2 )}>5 for the distances D.
29. The system of claim 1 , further comprising an additional electromagnetic resonator configured to receive resonant non-radiative wireless power from the first resonator.
30. A system for wirelessly providing power to a portable electronic device, the system comprising:
a first electromagnetic resonator coupled to a power supply, the first resonator having a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 );
a second electromagnetic resonator coupled to a load in the portable electronic device, the second resonator having a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ),
wherein the first and second resonators are wirelessly coupled to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ and an efficiency of at least 20% for distances D of at least 10 cm between the first and second resonators.
31. The system of claim 30 , wherein the portable electronic device is a cell phone, a computer, a robot, or a vehicle.
32. The system of claim 30 , further comprising a feedback mechanism coupled to at least one of the resonators to correct for frequency detuning.
33. The system of claim 30 , wherein the resonant frequencies f 1 =ω 1 /2π and f 2 =ω 2 /2π are each at least 5 MHz.
34. The system of claim 30 , wherein at least one of the electromagnetic resonators is tunable.
35. The system of claim 30 , wherein at least one of Q 1 and Q 2 is greater than 100.
36. The system of claim 30 , wherein the power supply and load are driven to increase the ratio of useful-to-lost power for the wireless energy transfer rate κ.
37. The system of claim 30 , wherein each of the electromagnetic resonators comprise a capacitive element and an inductive element.
38. A portable electronic device for use with a first electromagnetic resonator coupled to a power supply, the first resonator having a characteristic size L 1 , a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 ), the portable electronic device comprising:
a load; and
a second electromagnetic resonator configured to be coupled to the load and movable relative to the first resonator, the second resonator having a characteristic size L 2 , a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ),
wherein the second resonator is configured to be wirelessly coupled to the first resonator to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ, and
wherein the resonators satisfy κ/√{square root over (Γ 1 Γ 2 )}>1 for at least some distances D between the first and second resonators satisfying D/L 2 >1.
39. The device of claim 38 , wherein Q 2 >100.
40. The device of claim 38 , wherein (√{square root over (Q 1 Q 2 )})>100.
41. The device of claim 38 , wherein the second resonator is tunable.
42. The device of claim 38 , wherein the wireless power is at least 10 W.
43. The device of claim 38 , wherein the device is a cell phone, a computer, a robot, or a vehicle.
44. The device of claim 38 , wherein the resonant frequency f 2 =ω 2 /2π is at least 5 MHz.
45. The device of claim 38 , wherein the efficiency of the wireless power transfer is at least 20% for distances D of at least 10 cm between the first and second resonators.
46. The device of claim 38 , wherein during operation the load is driven to increase the ratio of useful-to-lost power for the wireless energy transfer rate κ.
47. A power source for wirelessly providing power to a portable electronic device, the power source comprising:
a power supply; and
a first electromagnetic resonator coupled to a power supply, the first resonator having a characteristic size L 1 , a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 ), the portable electronic device,
wherein the first resonator is configured to be wirelessly coupled to a second electromagnetic resonator in the portable electronic device to provide non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ,
wherein the second electromagnetic resonator is coupled to a load in the portable electronic device and movable relative to the first resonator, the second resonator having a characteristic size L 2 , a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ),
wherein the resonators satisfy κ/√{square root over (Γ 1 Γ 2 )}>1 for at least some distances D between the first and second resonators satisfying D/L 2 >1.
48. The power source of claim 47 , wherein Q 1 >100.
49. The power source of claim 47 , wherein (√{square root over (Q 1 Q 2 )})>100.
50. The power source of claim 47 , wherein the first resonator is tunable.
51. The power source of claim 47 , wherein the wireless power is at least 10 W.
52. The power source of claim 47 , wherein the device is a cell phone, a computer, a robot, or a vehicle.
53. The power source of claim 47 , wherein the resonant frequency f 1 =ω 1 /2π is at least 5 MHz.
54. The power source of claim 47 , wherein the efficiency of the wireless power transfer is at least 20% for distances D of at least 10 cm between the first and second resonators.
55. The power source of claim 47 , wherein during operation the power supply is driven to increase the ratio of useful-to-lost power for the wireless energy transfer rate κ.
56. A portable electronic device for use with a first electromagnetic resonator coupled to a power supply, the first resonator having a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 ), the portable electronic device comprising:
a load; and
a second electromagnetic resonator configured to be coupled to the load and movable relative to the first resonator, the second resonator having a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ),
wherein the second resonator is configured to be wirelessly coupled to the first resonator to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ, and
wherein the efficiency of the wireless power transfer is at least 20% for distances D of at least 10 cm between the first and second resonators.
57. The device of claim 56 , wherein Q 2 >100.
58. The device of claim 56 , wherein (√{square root over (Q 1 Q 2 )})>100.
59. The device of claim 56 , wherein the second resonator is tunable.
60. The device of claim 56 , wherein the device is a cell phone, a computer, a robot, or a vehicle.
61. The device of claim 56 , wherein the resonant frequency f 2 =ω 2 /2π is at least 5 MHz.
62. The device of claim 56 , wherein during operation the load is driven to increase the ratio of useful-to-lost power for the wireless energy transfer rate κ.
63. A power source for wirelessly providing power to a portable electronic device, the power source comprising:
a power supply; and
a first electromagnetic resonator coupled to a power supply, the first resonator having a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 ), the portable electronic device,
wherein the first resonator is configured to be wirelessly coupled to a second electromagnetic resonator in the portable electronic device to provide non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ,
wherein the second electromagnetic resonator is coupled to a load in the portable electronic device and movable relative to the first resonator, the second resonator having a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ),
wherein the efficiency of the wireless power transfer is at least 20% for distances D of at least 10 cm between the first and second resonators.
64. The power source of claim 63 , wherein Q 1 >100.
65. The power source of claim 63 , wherein (√{square root over (Q 1 Q 2 )})>100.
66. The power source of claim 63 , wherein the first resonator is tunable.
67. The power source of claim 63 , wherein the device is a cell phone, a computer, a robot, or a vehicle.
68. The power source of claim 63 , wherein the resonant frequency f 1 =ω 1 /2π is at least 5 MHz.
69. The power source of claim 63 , wherein during operation the power supply is driven to increase the ratio of useful-to-lost power for the wireless energy transfer rate κ.