Efficient near-field wireless energy transfer using adiabatic system variations

• US 9,831,682 B2
• Filed: 08/13/2014
• Issued: 11/28/2017
• Est. Priority Date: 10/01/2008
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Hamam, Rafif E., Karalis, Aristeidis, Joannopoulos, John D., Soljacic, Marin
• Primary Examiner(s): Chen, Sibin
• APPLICATION: US 20140354071A1
• Time in patent office: 1203 Days
• CPC Class Codes: H02J 17/00 Systems for supplying or distributing electric power by electromagnetic waves
• CPC Class Codes: H02J 5/005 with inductive power transfer for charging H02J7/025
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/025 using non-contact coupling, e.g. inductive, capacitive
• CPC Class Codes: H04B 5/0037 for power transfer

Abstract

Disclosed is a method for transferring energy wirelessly including transferring energy wirelessly from a first resonator structure to an intermediate resonator structure, wherein the coupling rate between the first resonator structure and the intermediate resonator structure is κ_1B, transferring energy wirelessly from the intermediate resonator structure to a second resonator structure, wherein the coupling rate between the intermediate resonator structure and the second resonator structure is κ_B2, and during the wireless energy transfers, adjusting at least one of the coupling rates κ_1B and κ_B2 to reduce energy accumulation in the intermediate resonator structure and improve wireless energy transfer from the first resonator structure to the second resonator structure through the intermediate resonator structure.

Claims

1. A method comprising:

transferring energy from a first resonant object to a second resonant object using a third resonant object to mediate the energy transfer, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, more strongly than the first resonant object is capable of resonantly coupling with the second resonant object; and

maintaining a reduced level of energy accumulation in the third resonant object by varying over time a coupling rate between the third resonant object and (i) the first resonant object, (ii) the second resonant object, or (iii) both, based on a loss rate of (i) the first resonant object, (ii) the second resonant object, or (iii) both;

wherein the reduced level of energy accumulation is reduced relative to energy accumulation that would occur in the third resonant object without the varying of the coupling rate over time.

2. The method of claim 1, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, at least five times more strongly than the first resonant object is capable of resonantly coupling with the second resonant object.

3. The method of claim 1, wherein varying the coupling rate comprises changing a relative orientation between one or more pairs of the first resonant object, the second resonant object, and the third resonant object.

4. The method of claim 1, wherein varying the coupling rate comprises changing a relative position between one or more pairs of the first resonant object, the second resonant object, and the third resonant object.

5. The method of claim 1, wherein varying the coupling rate comprises changing a size of at least one of the first resonant object, the second resonant object, or the third resonant object.

6. A method comprising:

transferring energy from a first resonant object to a second resonant object using a third resonant object to mediate the energy transfer, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, more strongly than the first resonant object is capable of resonantly coupling with the second resonant object; and

maintaining a reduced level of energy accumulation in the third resonant object by varying over time a coupling rate between the third resonant object and (i) the first resonant object, (ii) the second resonant object, or (iii) both, based on a loss rate of (i) the first resonant object, (ii) the second resonant object, or (iii) both;

wherein;

transferring the energy comprises wirelessly transferring energy from the first resonant object to the second resonant object using the third resonant object to mediate the wireless energy transfer; and

maintaining the reduced level of energy accumulation in the third resonant object comprises varying both (i) a coupling rate between the first resonant object and the third resonant object and (ii) a coupling rate between the third resonant object and the second resonant object, over time in accordance with an adiabatic time evolution of an eigenstate for the three resonant objects.

7. The method of claim 6, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, at least five times more strongly than the first resonant object is capable of resonantly coupling with the second resonant object.

8. The method of claim 6, wherein the first resonant object has a loss rate unequal to that of the second resonant object.

9. The method of claim 6, wherein each of the first resonant object, the second resonant object, and the third resonant object has a resonant frequency between 50 kHz and 500 MHz.

10. The method of claim 6, wherein varying the coupling rate comprises changing a relative orientation between one or more pairs of the first resonant object, the second resonant object, and the third resonant object.

11. The method of claim 6, wherein varying the coupling rate comprises changing a relative position between one or more pairs of the first resonant object, the second resonant object, and the third resonant object.

12. The method of claim 6, wherein varying the coupling rate comprises changing a resonator property of at least one of the first resonant object, the second resonant object, or the third resonant object.

13. The method of claim 6, wherein varying the coupling rate comprises changing a size of at least one of the first resonant object, the second resonant object, or the third resonant object.

14. A system comprising:

a first resonant object to provide energy;

a second resonant object to receive energy;

a third resonant object to mediate energy transfer between the first resonant object and the second resonant object, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, more strongly than the first resonant object is capable of resonantly coupling with the second resonant object; and

a control mechanism configured and arranged to maintain a reduced level of energy accumulation in the third resonant object by varying over time a coupling rate between the third resonant object and (i) the first resonant object, (ii) the second resonant object, or (iii) both, based on a loss rate of (i) the first resonant object, (ii) the second resonant object, or (iii) both;

wherein the reduced level of energy accumulation is reduced relative to energy accumulation that would occur in the third resonant object without the varying of the coupling rate over time.

15. The system of claim 14, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, at least five times more strongly than the first resonant object is capable of resonantly coupling with the second resonant object.

16. The system of claim 14, wherein the control mechanism is configured and arranged to change a relative orientation between one or more pairs of the first resonant object, the second resonant object, and the third resonant object.

17. The system of claim 14, wherein the control mechanism is configured and arranged to change a relative position between one or more pairs of the first resonant object, the second resonant object, and the third resonant object.

18. The system of claim 14, wherein the control mechanism is configured and arranged to change a size of at least one of the first resonant object, the second resonant object, or the third resonant object.

19. A system comprising:

a first resonant object to provide energy;

a second resonant object to receive energy;

a third resonant object to mediate energy transfer between the first resonant object and the second resonant object, wherein the third resonant object is capable of resonantly coupling with (i) the first resonant object, (ii) the second resonant object, or (iii) both, more strongly than the first resonant object is capable of resonantly coupling with the second resonant object; and

a control mechanism configured and arranged to improve energy transfer by varying over time a coupling rate between the third resonant object and (i) the first resonant object, (ii) the second resonant object, or (iii) both, based on a loss rate of (i) the first resonant object, (ii) the second resonant object, or (iii) both;

wherein the first resonant object is a first wireless resonator, the second resonant object is a second wireless resonator, the third resonant object is a third wireless resonator, and the control mechanism is configured and arranged to vary both (i) a coupling rate between the first wireless resonator and the third wireless resonator and (ii) a coupling rate between the third wireless resonator and the second wireless resonator, over time in accordance with an adiabatic time evolution of an eigenstate for the three wireless resonators.

20. The system of claim 19, wherein the third wireless resonator is capable of resonantly coupling with (i) the first wireless resonator, (ii) the second wireless resonator, or (iii) both, at least five times more strongly than the first wireless resonator is capable of resonantly coupling with the second wireless resonator.

21. The system of claim 19, wherein the first wireless resonator has a loss rate unequal to that of the second wireless resonator.

22. The system of claim 19, wherein each of the first wireless resonator, the second wireless resonator, and the third wireless resonator has a resonant frequency between 50 kHz and 500 MHz.

23. The system of claim 19, wherein the control mechanism is configured and arranged to change a relative orientation between one or more pairs of the first wireless resonator, the second wireless resonator, and the third wireless resonator.

24. The system of claim 19, wherein the control mechanism is configured and arranged to change a relative position between one or more pairs of the first wireless resonator, the second wireless resonator, and the third wireless resonator.

25. The system of claim 19, wherein the control mechanism is configured and arranged to change a resonator property of at least one of the first wireless resonator, the second wireless resonator, or the third wireless resonator.

26. The system of claim 19, wherein the control mechanism is configured and arranged to change a size of at least one of the first wireless resonator, the second wireless resonator, or the third wireless resonator.

27. An apparatus comprising:

an intermediary wireless resonator to mediate energy transfer between a source wireless resonator and a destination wireless resonator, wherein the intermediary wireless resonator is capable of resonantly coupling with (i) the source wireless resonator, (ii) the destination wireless resonator, or (iii) both, more strongly than the source wireless resonator is capable of resonantly coupling with the destination wireless resonator; and

a control mechanism configured and arranged to maintain a reduced level of energy accumulation in the intermediary wireless resonator by varying over time a coupling rate between the source wireless resonator and the intermediary wireless resonator and between the intermediary wireless resonator and the destination wireless resonator;

wherein the reduced level of energy accumulation is reduced relative to energy accumulation that would occur in the intermediary wireless resonator without the varying of the coupling rate over time.

28. The apparatus of claim 27, wherein the control mechanism is configured and arranged to change an orientation, a resonator property, or a size of the intermediary wireless resonator.