Wireless energy transfer with variable size resonators for implanted medical devices

• US 8,901,778 B2
• Filed: 10/21/2011
• Issued: 12/02/2014
• Est. Priority Date: 09/27/2008
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Kesler, Morris P., Hall, Katherine L., Kulikowski, Konrad, Karalis, Aristeidis, Kurs, Andre B., Soljacic, Marin, Campanella, Andrew J., Efe, Volkan
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Mourad, Rasem
• Application Number:
  US13/279,007
• Publication Number:
  US 20120235633A1
• Time in Patent Office: 1,138 Days
• Field of Search: 307/104, 320/108
• US Class Current: 307/104
• 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 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance

Abstract

A medical device-powering wireless receiver for use with a first electromagnetic resonator coupled to a power supply. The wireless receiver including a load is configured to power the medical device using electrical power, and a second electromagnetic resonator adapted to be housed within the medical device and configured to be coupled to the load, wherein the second electromagnetic resonator is configured to be wirelessly coupled to the first electromagnetic resonator to provide resonant, non-radiative wireless power to the second electromagnetic resonator from the first electromagnetic resonator, the area circumscribed by the inductive element of at least one of the electromagnetic resonators can be varied to improve performance.

Claims

1. A medical device-powering wireless receiver for use with a first electromagnetic resonator coupled to a power supply, first electromagnetic resonator having a mode with a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and a first Q-factor Q₁=ω

₁/2Γ

₁, the wireless receiver comprising;

a load configured to power the medical device using electrical power; and

a second electromagnetic resonator adapted to be integrated with the medical device or the load, the second electromagnetic resonator having a mode with a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and a second Q-factor Q₂=ω

₂/2Γ

₂;

wherein the second electromagnetic resonator is configured to be wirelessly coupled to the first electromagnetic resonator to provide resonant, non-radiative wireless power to the second electromagnetic resonator from the first electromagnetic resonator;

wherein an inductive element of at least one of the electromagnetic resonators comprises a plurality of conductors;

wherein the at least one of the electromagnetic resonators comprises a collection of switches coupled with the plurality of conductors and configured to selectively connect one or more of the plurality of conductors to vary an effective size of the at least one of the electromagnetic resonators to improve performance;

wherein the square root of the product of the respective Q factors is greater than 100; and

wherein the plurality of conductors comprise a series of concentric loops with decreasing radii.

2. The wireless receiver of claim 1, wherein the first electromagnetic resonator is the at least one of the electromagnetic resonators, the second electromagnetic resonator is a fixed size device resonator, the medical device is implanted in a patient, and the first electromagnetic resonator is more than twice as large as the second electromagnetic resonator.

3. The wireless receiver of claim 2, wherein the effective size of the first electromagnetic resonator is selected for a given separation, position and/or orientation of the patient by adjusting the effective size of the first electromagnetic resonator relative to the fixed size device resonator.

4. The wireless receiver of claim 1, wherein the second electromagnetic resonator is the at least one of the electromagnetic resonators.

5. The wireless receiver of claim 1, wherein the medical device is implanted in a patient, and the effective size of the at least one of the electromagnetic resonators is adjusted in response to movement of the second electromagnetic resonator relative to the first electromagnetic resonator while transferring effective power.

6. The wireless receiver of claim 1, wherein the medical device is a diagnostic device.

7. A power source for wirelessly providing power to a wireless receiver of an electrically powered medical device, the power source comprising:

a power supply, the power supply configured to supply power at a rate sufficient to charge a battery of the medical device; and

a first electromagnetic resonator coupled to the power supply and having a mode with a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and a first Q-factor Q₁=ω

₁/2Γ

₁, the first electromagnetic resonator housed in a housing configured to be disposed remotely from the medical device;

wherein the first electromagnetic resonator is configured to be wirelessly coupled to a second electromagnetic resonator integrated with the medical device or a load associated with the medical device to provide non-radiative wireless power to the second electromagnetic resonator, the second electromagnetic resonator having a mode with a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and a second Q-factor Q₂=ω

₂/2Γ

₂;

wherein an inductive element of at least one of the electromagnetic resonators comprises a plurality of conductors;

wherein the at least one of the electromagnetic resonators comprises a collection of switches coupled with the plurality of conductors and configured to selectively connect one or more of the plurality of conductors to vary an effective size of the at least one of the electromagnetic resonators to improve performance;

wherein the square root of the product of the respective Q factors is greater than 100;

wherein the first electromagnetic resonator is the at least one of the electromagnetic resonators, the second electromagnetic resonator is a fixed size device resonator, the medical device is implanted in a patient, and the first electromagnetic resonator is more than twice as large as the second electromagnetic resonator; and

wherein the plurality of conductors comprise a series of concentric loops with decreasing radii.

8. The power source of claim 7, wherein the effective size of the first electromagnetic resonator is selected for a given separation, position and/or orientation of the patient by adjusting the effective size of the first electromagnetic resonator relative to the fixed size device resonator.

9. The power source of claim 7, wherein the effective size of the first electromagnetic resonator is adjusted in response to movement of the second electromagnetic resonator relative to the first electromagnetic resonator while transferring effective power.

10. The power source of claim 7, wherein the medical device is a diagnostic device.

11. A medical device wireless power system, comprising:

a power supply, the power supply configured to supply power at a rate sufficient to charge a medical device implanted in a patient;

a first electromagnetic resonator coupled to the power supply and having a mode with a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and a first Q-factor Q₁=ω

₁/2Γ

₁, the first electromagnetic resonator housed in a housing configured to be disposed remotely from the medical device;

a load configured to power the medical device using electrical power; and

a second electromagnetic resonator adapted to be integrated with the medical device or the load, the second electromagnetic resonator having a mode with a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and a second Q-factor Q₂=ω

₂/2Γ

₂;

wherein the first electromagnetic resonator is configured to be wirelessly coupled to the second electromagnetic resonator within the medical device to provide non-radiative wireless power to the second electromagnetic resonator;

wherein an inductive element of at least one of the electromagnetic resonators comprises a plurality of conductors;

wherein the at least one of the electromagnetic resonators comprises a collection of switches coupled with the plurality of conductors and configured to selectively connect one or more of the plurality of conductors to vary an effective size of the at least one of the electromagnetic resonators to improve performance;

wherein the square root of the product of the respective Q factors is greater than 100; and

wherein the first electromagnetic resonator is the at least one of the electromagnetic resonators, the medical device is one of a plurality of medical devices having different sized device resonators that realize maximum transfer efficiency for different sized source resonators, and the first electromagnetic resonator'"'"'s effective size is altered to preferentially charge a first of the plurality of medical devices over a second of the plurality of medical devices.

12. The wireless power system of claim 11, wherein the first electromagnetic resonator is more than twice as large as the second electromagnetic resonator.

13. The wireless power system of claim 11, wherein the effective size of the at least one of the electromagnetic resonators is selected relative to the other of the electromagnetic resonators for a given separation, position and/or orientation of the patient.

14. The wireless power system of claim 11, wherein the plurality of conductors comprise a series of concentric loops with decreasing radii.

15. The wireless power system of claim 11, wherein the effective size of the at least one of the electromagnetic resonators is adjusted in response to movement of the second electromagnetic resonator relative to the first electromagnetic resonator while transferring effective power.

16. The wireless power system of claim 11, wherein the medical device is a diagnostic device.

17. A medical device wireless power system, comprising:

a power supply, the power supply configured to supply power at a rate sufficient to charge a medical device implanted in a patient;

a first electromagnetic resonator coupled to the power supply and having a mode with a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and a first Q-factor Q₁=ω

₁/2Γ

₁, the first electromagnetic resonator housed in a housing configured to be disposed remotely from the medical device;

a load configured to power the medical device using electrical power; and

a second electromagnetic resonator adapted to be integrated with the medical device or the load, the second electromagnetic resonator having a mode with a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and a second Q-factor Q₂=ω

₂/2Γ

₂;

wherein the first electromagnetic resonator is configured to be wirelessly coupled to the second electromagnetic resonator within the medical device to provide non-radiative wireless power to the second electromagnetic resonator;

wherein an inductive element of at least one of the electromagnetic resonators comprises a plurality of conductors;

wherein the at least one of the electromagnetic resonators comprises a collection of switches coupled with the plurality of conductors and configured to selectively connect one or more of the plurality of conductors to vary an effective size of the at least one of the electromagnetic resonators to improve performance;

wherein the square root of the product of the respective Q factors is greater than 100; and

wherein the first electromagnetic resonator is the at least one of the electromagnetic resonators, the medical device is one of a plurality of medical devices, and the first electromagnetic resonator'"'"'s effective size is altered based on a number of the plurality of medical devices and a distribution of the plurality of medical devices.

18. The wireless power system of claim 17, wherein the first electromagnetic resonator is more than twice as large as the second electromagnetic resonator.

19. The wireless power system of claim 17, wherein the effective size of the at least one of the electromagnetic resonators is selected relative to the other of the electromagnetic resonators for a given separation, position and/or orientation of the patient.

20. The wireless power system of claim 17, wherein the plurality of conductors comprise a series of concentric loops with decreasing radii.

21. The wireless power system of claim 17, wherein the effective size of the at least one of the electromagnetic resonators is adjusted in response to movement of the second electromagnetic resonator relative to the first electromagnetic resonator while transferring effective power.

22. The wireless power system of claim 17, wherein the medical device is a diagnostic device.