Wireless energy transfer
Disclosed is an apparatus for use in wireless energy transfer, which includes a first resonator structure configured to transfer energy non-radiatively with a second resonator structure over a distance greater than a characteristic size of the second resonator structure. The non-radiative energy transfer is mediated by a coupling of a resonant field evanescent tail of the first resonator structure and a resonant field evanescent tail of the second resonator structure.
1. A source assembly for use with a wireless power system including a device resonator and a load coupled to the device resonator to receive power from the device resonator, the device resonator having a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and an intrinsic quality factor Q 2 =ω 2 /(2Γ 2 )>100, the source assembly comprising:
a source resonator having a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and an intrinsic quality factor Q 1 =ω 1 /(2Γ 1 )>100; and
a current probe configured to measure a current in the source resonator,
wherein the source resonator and the device resonator are configured to resonantly and wirelessly couple electromagnetic power from the source resonator to the device resonator over a range of distances D between the source resonator and the device resonator using non-radiative electromagnetic induction having a coupling coefficient K.
2. The source assembly of claim 1 , further comprising a power supply coupled to the source resonator to provide power to the source resonator.
3. The source assembly of claim 1 , wherein the intrinsic loss rates satisfy κ/√{square root over (Γ 1 Γ 2 )}>2 over the range of distances D between the source resonator and the device resonator.
4. The source assembly of claim 1 , further comprising a monitor configured to measure an efficiency of power coupled to the load from the source resonator using information from the current measurement.
5. The source assembly of claim 4 , further comprising a frequency adjuster configured to adjust a frequency of the wireless energy transfer based on the measurement by the monitor.
6. The source assembly of claim 5 , wherein the frequency adjuster is configured to adjust the resonant frequency of the source resonator.
7. The source assembly of claim 4 , wherein the resonators wirelessly exchange information based on the measurement by the monitor.
8. The source assembly of claim 1 , wherein f 1 =ω 1 /(2π) and f 1 is between 1 MHz and 10 MHz.
9. The source assembly of claim 1 , wherein Q 1 >200.
10. The source assembly of claim 9 , wherein f 1 =ω 1 /(2π) and f 1 is between 10 KHz and 1 MHz.
11. A device assembly for use with a wireless power system including a source resonator and a power supply coupled to the source resonator to provide power to the source resonator, the source resonator having a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and an intrinsic quality factor Q 1 =ω 1 /(2Γ 1 )>100, the device assembly comprising:
a device resonator having a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and an intrinsic quality factor Q 2 =ω 2 /(2Γ 2 )>100; and
a current probe configured to measure a current in the device resonator,
wherein the source resonator and the device resonator are configured to resonantly and wirelessly couple electromagnetic power from the source resonator to the device resonator over a range of distances D between the source resonator and the device resonator using non-radiative electromagnetic induction having a coupling coefficient κ.
12. The device assembly of claim 11 , further comprising a load coupled to the device resonator to receive power from the device resonator.
13. The device assembly of claim 11 , wherein the intrinsic loss rates satisfy κ/√{square root over (Γ 1 Γ 2 )}>2 over the range of distances D between the source resonator and the device resonator.
14. The device assembly of claim 11 , further comprising a monitor configured to measure an efficiency of power coupled to the load from the source resonator using information from the current measurement.
15. The device assembly of claim 14 , further comprising a frequency adjuster configured to adjust a frequency of the wireless energy transfer based on the measurement by the monitor.
16. The device assembly of claim 15 , wherein the frequency adjuster is configured to adjust the resonant frequency of the device resonator.
17. The device assembly of claim 14 , wherein the resonators wirelessly exchange information based on the measurement by the monitor.
18. The device assembly of claim 11 , wherein f 2 =ω 2 /(2π) and f 2 is between 1 MHz and 10 MHz.
19. The device assembly of claim 11 , wherein Q 2 >200.
20. The device assembly of claim 19 , wherein f 2 =ω 2 /(2π) and f 2 is between 10 KHz and 1 MHz.
21. A vehicle configured for use with a wireless power system including a source resonator and a power supply coupled to the source resonator to provide power to the source resonator, the source resonator having a resonant frequency ω 1 , an intrinsic loss rate Γ 1 , and an intrinsic quality factor Q 1 =ω 1 /(2Γ 1 )>100, the vehicle comprising:
a device resonator having a resonant frequency ω 2 , an intrinsic loss rate Γ 2 , and an intrinsic quality factor Q 2 =ω 2 /(2Γ 2 )>100;
a load coupled to the device resonator to receive power from the device resonator; and
a current probe configured to measure a current in the device resonator,
wherein the source resonator and the device resonator are configured to resonantly and wirelessly couple electromagnetic power from the source resonator to the device resonator over a range of distances D between the source resonator and the device resonator using non-radiative electromagnetic induction having a coupling coefficient κ.
22. The vehicle of claim 21 , further comprising a monitor configured to measure an efficiency of power coupled to the load from the source resonator using information from the current measurement.
23. The vehicle of claim 22 , further comprising a frequency adjuster configured to adjust a frequency of the wireless energy transfer based on the measurement by the monitor.
24. The vehicle of claim 23 , wherein the frequency adjuster is configured to adjust the resonant frequency of the device resonator.
25. The vehicle of claim 22 , wherein the resonators wirelessly exchange information based on the measurement by the monitor.
26. The vehicle of claim 21 , wherein Q 1 >200 and Q 2 >200, wherein the load is configured to provide power to a vehicle, wherein the intrinsic loss rates satisfy κ/√{square root over (Γ 1 Γ 2 )} >5 over the range of distances D, and wherein the power provided to the load from the device resonator is greater than about 10 Watt.
27. The vehicle of claim 26 , wherein f 1 =ω 1 /(2π) and f 2 =ω 2 /(2π), and f 1 and f 6 are between 10 kHz and 1 MHz.