Wireless energy transfer for implantable devices
Wireless energy transfer apparatus include, in at least one aspect, a device resonator configured to supply power for a load by receiving wirelessly transferred power from a source resonator; a temperature sensor positioned to measure a temperature of a component of the apparatus; a tunable component coupled to the device resonator to adjust a resonant frequency of the device resonator, an effective impedance the device resonator, or both; and control circuitry configured to, in response to detecting a temperature condition using the temperature sensor, (i) tune the tunable component to adjust the resonant frequency of the device resonator, the effective impedance of the device resonator, or both, and (ii) signal the source resonator regarding the temperature condition to cause an adjustment of a resonant frequency of the source resonator, a power output of the source resonator, or both.
1. A wireless energy transfer apparatus for an implantable medical device, the apparatus comprising:
a device resonator configured to supply power for a load of the implantable medical device by receiving wirelessly transferred power from a source resonator coupled with a power source;
a temperature sensor positioned to measure a component of the apparatus;
a tunable component coupled to the device resonator to adjust a resonant frequency of the device resonator, an effective impedance the device resonator, or both; and
control circuitry coupled with the temperature sensor and the tunable component;
wherein the control circuitry is configured to, in response to detecting a temperature condition using the temperature sensor positioned to measure the temperature of the component of the apparatus,
(i) tune the tunable component to adjust the resonant frequency of the device resonator, the effective impedance of the device resonator, or both, and
(ii) signal the source resonator regarding the temperature condition to cause an adjustment of a resonant frequency of the source resonator, a power output of the source resonator, or both.
2. The wireless energy transfer apparatus of claim 1 , wherein the control circuitry comprises a communication controller coupled to wireless communication circuitry useable to signal the source resonator regarding the temperature condition.
3. The wireless energy transfer apparatus of claim 1 , wherein the tunable component comprises a variable capacitor.
4. The wireless energy transfer apparatus of claim 1 , wherein the tunable component comprises a bank of capacitors.
5. The wireless energy transfer apparatus of claim 1 , wherein the tunable component comprises an inductor.
6. The wireless energy transfer apparatus of claim 1 , wherein the device resonator has a Q>100.
7. The wireless energy transfer apparatus of claim 1 , wherein the control circuitry is configured to continuously monitor temperatures of the component of the apparatus and trends of the temperatures of the component of the apparatus, and adjust the tunable component to stabilize the temperature of the component of the apparatus.
8. The wireless energy transfer apparatus of claim 7 , wherein the tunable component comprises at least one inductor or at least one capacitor of the component of the apparatus that the temperature sensor is positioned to measure.
9. The wireless energy transfer apparatus of claim 1 , wherein the device resonator is tuned incrementally until the temperature stabilizes.
10. The wireless energy transfer apparatus of claim 9 , wherein the device resonator is tuned in increments of 1 kHz or more.
11. The wireless energy transfer apparatus of claim 1 , wherein the tunable component is adjusted to tune the resonant frequency of the device resonator to be above the resonant frequency of the source resonator.
12. The wireless energy transfer apparatus of claim 1 , wherein the tunable component is adjusted to tune the resonant frequency of the device resonator to be below the resonant frequency of the source resonator.
13. The wireless energy transfer apparatus of claim 1 , wherein the tunable component is adjusted to maintain the temperature of the component of the apparatus below 50 degrees Celsius.
14. The wireless energy transfer apparatus of claim 1 , comprising a rechargeable battery, wherein the device resonator is coupled with the implantable medical device and supplies power to the load through the rechargeable battery.
15. A wireless energy transfer system comprising:
the wireless energy transfer apparatus of claim 1 ; and
the source resonator;
wherein the device resonator and the source resonator are tuned to increase overall heat dissipation by reducing heat dissipation occurring in the device resonator and increasing heat dissipation occurring in the source resonator.
16. The wireless energy transfer system of claim 15 , comprising an active cooling system for the source resonator.
17. The wireless energy transfer system of claim 16 , wherein the active cooling system for the source resonator comprises a fan.
18. The wireless energy transfer system of claim 16 , wherein the active cooling system for the source resonator is configured to safely dissipate 5 watts or more of heat.
19. The wireless energy transfer system of claim 16 , wherein the active cooling system for the source resonator comprises a water cooling system.
20. The wireless energy transfer system of claim 16 , wherein the active cooling system for the source resonator is configured to safely dissipate 15 watts or more of power.