Self-tuning resonant power transfer systems

• US 9,997,928 B2
• Filed: 02/05/2016
• Issued: 06/12/2018
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Inventors: Petersen, Ethan, Hansen, John Freddy
• Primary Examiner(s): KAPLAN, HAL IRA
• Application Number:
  US15/016,840
• Publication Number:
  US 20160190819A1
• Time in Patent Office: 858 Days
• Field of Search: 307104, 320108
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/30 using light, e.g. lasers

Abstract

Systems and designs for tuning a wireless power transfer system are provided, which may include any number of features. In one embodiment, a wireless power transfer system can be configured such that resonant frequencies of the system move towards an operating frequency of the system as a coupling coefficient between the transmit and receive resonators becomes smaller. In another embodiment, a receive controller can be configured to control a current delivered to a DC load by comparing an actual current at the DC load to a current requested by the DC load and adjusting an angle or a magnitude of a voltage at the DC load to match the requested current. In another embodiment, a rectifier circuit can act as a controlled voltage source and be configured to tune resonant frequencies between the transmit resonator and the receive resonator. Methods of use are also provided.

Claims

1. A wireless power transfer system comprising:

a transmitter comprising a transmit resonator coupled to a voltage source; and

a receiver comprising a receive resonator coupled to a load through a rectifier circuit, wherein the system is configured to be actively tuned by modifying a reactance of the load to tune a resonant frequency of the transmit and receive resonators.

2. The wireless power transfer system of claim 1, wherein the rectifier circuit is a full bridge rectifier circuit, such that the receiver functions as a controlled voltage source.

3. The wireless power transfer system of claim 1, wherein the rectifier circuit comprises a plurality of field effect transistors (FETs).

4. The wireless power transfer system of claim 3, wherein the plurality of FETs are configured to operate to change a power factor of the load.

5. The wireless power transfer system of claim 1, wherein the system is configured such that varying a voltage and a phase of the voltage source controls power transmitted through the system.

6. The wireless power transfer system of claim 1, wherein the system is configured such that varying a voltage and a phase of the rectifier circuit controls power transmitted through the system.

7. The wireless power transfer system of claim 1, wherein the system is further configured to self-tune by automatically moving the resonant frequency of the transmit and receive resonators towards an operating frequency of the system as a coupling coefficient between the transmit and receive resonators becomes smaller.

8. The wireless power transfer system of claim 7, wherein the self-tuning is optimized to maintain a voltage gain within a specified range as the coupling coefficient varies.

9. The wireless power transfer system of claim 7, wherein the self-tuning is optimized to maximize efficiency over a given range.

10. The wireless power transfer system of claim 7, wherein the self-tuning is optimized to achieve a minimum amount of power transferred for a given source voltage.

11. A method of operating a wireless power transfer system, the method comprising:

inductively coupling a transmitter to a receiver, the transmitter including a transmit resonator coupled to a voltage source, and the receiver including a receive resonator coupled to a load through a rectifier circuit; and

actively tuning a resonant frequency of the transmit and receive resonators by modifying a reactance of the load.

12. The method of claim 11, wherein the rectifier circuit is a full bridge rectifier circuit, such that the receiver functions as a controlled voltage source.

13. The method of claim 11, wherein the rectifier circuit comprises a plurality of field effect transistors (FETs).

14. The method of claim 13, wherein modifying a reactance of the load comprises controlling the plurality of FETs to change a power factor of the load.

15. The method of claim 11, further comprising varying a voltage and a phase of the voltage source to control power transmitted through the system.

16. The method of claim 11, further comprising varying a voltage and a phase of the rectifier circuit to control power transmitted through the system.

17. The method of claim 11, further comprising self-tuning the wireless power transfer system by automatically moving the resonant frequency of the transmit and receive resonators towards an operating frequency of the system as a coupling coefficient between the transmit and receive resonators becomes smaller.

18. The method of claim 17, wherein self-tuning the wireless power transfer system comprises self-tuning the wireless power transfer system to maintain a voltage gain within a specified range as the coupling coefficient varies.

19. The method of claim 17, wherein self-tuning the wireless power transfer system comprises self-tuning the wireless power transfer system to maximize efficiency over a given range.

20. The method of claim 17, wherein self-tuning the wireless power transfer system comprises self-tuning the wireless power transfer system to achieve a minimum amount of power transferred for a given source voltage.