WIRELESS ENERGY TRANSFER

• US 20140265617A1
• Filed: 03/06/2014
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Abandoned Application

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Roy, Arunanshu Mohan, Efe, Volkan, Karalis, Aristeidis, Kurs, Andre B., McCauley, Alexander Patrick, Kesler, Morris P., Hall, Katherine L.
• Application Number:
  US14/199,083
• Publication Number:
  US 20140265617A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

A wireless power system includes: i) a power source; ii) a source resonator configured to receive power from the power source; iii) a receiver resonator configured to provide power to a load; and iv) at least one repeater resonator configured to couple power wirelessly from the source resonator to the receiver resonator. The power source is configured to provide power to the source resonator at a first frequency f₁ different from at least one of the resonant frequencies corresponding to the resonators.

Claims

1. A wireless power system comprising:

a power source;

a source resonator configured to receive power from the power source, wherein the source resonator has a resonant frequency f_s=ω

_s/2π

, an intrinsic loss rate Γ

_s, and is capable of storing electromagnetic energy with an intrinsic quality factor Q_s=ω

_s/(2Γ

_s);

a receiver resonator configured to provide power to a load, wherein the receiver resonator has a resonant frequency f_rc=ω

_rc/2π

, an intrinsic loss rate Γ

_rc, and is capable of storing electromagnetic energy with an intrinsic quality factor Q_rc=ω

_rc/(2Γ

_rc); and

at least one repeater resonator configured to couple power wirelessly from the source resonator to the receiver resonator, wherein the at least one repeater resonator has a resonant frequency f_r1=ω

_r1/2π

, an intrinsic loss rate Γ

_r1, and is capable of storing electromagnetic energy with an intrinsic quality factor Q_r1=ω

_r1/(2Γ

_r1), and

wherein the power source is configured to provide power to the source resonator at a first frequency f₁ different from at least one of the resonant frequencies.

2. The system of claim 1, wherein the first frequency f₁ differs from at least one of the resonant frequencies by more than 3%.

3. The system of claim 1, wherein the resonators are spatially distributed, and wherein the spatial distribution of the resonators causes the receiving resonator to receive power from the source resonator through the at least one repeater resonator with an energy transfer efficiency η

₁ larger than 30% and wherein η

₁ varies by less than 5% when f₁ varies by less than 5%.

4. The system of claim 1, wherein at least one of the intrinsic quality factors is greater than 100.

5. The system of claim 1, wherein at least one of the resonators comprises a capacitively loaded conducting wire loop.

6. The system of claim 1, wherein the resonators are spatially distributed, and wherein the spatial distribution of the resonators causes the receiving resonator to receive power from the source resonator through the at least one repeater resonator with an energy transfer efficiency η

₁, when the power source provides power to the source resonator at a frequency that differs from at least one of the resonant frequencies by more than 3%, and with an energy efficiency η

_o<

η

₁, when the power source provides power to the source resonator at a frequency that does not differ from the at least one of the resonant frequencies by more than 3%.

7. The system of claim 1, wherein during operation the power source is configured to vary the frequency of the power provided to the source resonator.

8. The system of claim 7, wherein during operation the power source is configured to adjust the frequency of the power provided to the source resonator to at least one other frequency f₀ within a range of frequencies including the first frequency f₁.

9. The system of claim 8, wherein the frequency f₀ is equal to the resonant frequency of at least one of the resonators.

10. The system of claim 8, wherein the frequency f₀ differs from the resonant frequency of at least one of the resonators by at least 5%.

11. The system of claim 7, wherein the power source is configured to vary the frequency of the power provided to the source resonator as at least one of the resonators moves relative to another one of the resonators.

12. The system of claim 11, wherein during operation the power source is configured to is configured to provide power to the source resonator at the frequencies f₁ and f₀ at the same time.

13. The system of claim 1, wherein the first frequency f₁ differs from the resonant frequency of at least one of the resonators by an amount greater than the intrinsic loss rate for the at least one resonator.

14. A wireless power method comprising:

providing power from a power source to a source resonator;

wherein the source resonator has a resonant frequency f_s=ω

_s/2π

, an intrinsic loss rate Γ

_s, and is capable of storing electromagnetic energy with an intrinsic quality factor Q_s=ω

_s/(2Γ

_s);

wirelessly transferring power from the source resonator to a receiver resonator through at least one repeater resonator, wherein the receiver resonator has a resonant frequency f_rcω

_rc/2π

, an intrinsic loss rate Γ

_rc, and is capable of storing electromagnetic energy with an intrinsic quality factor Q_rc=ω

_rc/(2Γ

_rc) and the at least one repeater resonator has a resonant frequency f_r1=ω

_r1/2π

, an intrinsic loss rate Γ

_r1, and is capable of storing electromagnetic energy with an intrinsic quality factor Q_r1=ω

_r1/(2Γ

_r1); and

providing power from the receiver resonator to a load,

wherein the power source provides power to the source resonator at a first frequency f₁ different from at least one of the resonant frequencies.

15. The method of claim 14, the method comprising:

providing energy from the power source to the source resonator at an operating frequency f_o;

wirelessly transferring energy from the source resonator to one or more receiving resonators through the at least one repeater resonator at the operating frequency f_o; and

adjusting the operating frequency f_o to include at least the first frequency f₁ different from at least one of the resonant frequencies corresponding to the resonators to control the energy transfer distribution to the one or more receiving resonators.

16. The method of claim 14, the method comprising:

providing energy from the power source to the source resonator at an operating frequency f_o;

wirelessly transferring energy from the source resonator to one or more receiving resonators through the at least one repeater resonator at the operating frequency f_o; and

adjusting the operating frequency f_o to include at least the first frequency f₁ different from the resonant frequency f_s of the source resonator.

17. The method of claim 16, further comprising measuring a property of the wireless energy transfer as the operating frequency is adjusted to determine an operating frequency f_o that improves the wireless energy transfer relative to that for an operating frequency f_o equal to the resonant frequency f_s for the source resonator.

18. The method of claim 17, further comprising adjusting a position of one or more of the resonators.

19. The method of claim 18, further comprising measuring a property of the wireless energy transfer as a function of the adjusted operating frequency and the adjusted position of the one or more resonators.

20. The method of claim 17, wherein the measured property of the wireless energy transfer is an energy output from the source resonator or an energy input to the one or more receiving resonators.

21. The method of claim 17, wherein the measured property of the wireless energy transfer is an efficiency of the wireless energy transfer to the one or more receiving resonators.

22. The method of claim 17, wherein the measured property of the wireless energy transfer is an impedance spectrum of one or more of the resonators.

23. A method for configuring a wireless power system, the method comprising:

providing a power source to provide power to a source resonator at an operating frequency f_o;

positioning one or more receiver resonators, each coupled to a load, at respective desired positions;

positioning at least one repeater resonator to wirelessly transfer energy from the source resonator to one or more receiving resonators through the at least one repeater resonator; and

adjusting the operating frequency f_o and/or the position of at least one of the repeater resonators to improve the wireless energy transfer to the one or more receiver resonators, wherein the operating frequency f_o is adjusted to include at least a first frequency f₁ different from at least one of the resonant frequencies corresponding to the resonators.

24. The method of claim 23, further comprising measuring a property of the wireless energy transfer as a function of the adjustment to the operating frequency and/or position of the at least one repeater resonator.

25. The method of claim 23, wherein the operating frequency f_o and the position of at least one of the repeater resonators are adjusted to improve the wireless energy transfer to the one or more receiver resonators.