Self-tuning resonant power transfer systems

• US 9,287,040 B2
• Filed: 07/29/2013
• Issued: 03/15/2016
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: Thoratec LLC
• Inventors: Petersen, Ethan, Hansen, John Freddy
• Primary Examiner(s): Kaplan, Hal
• Application Number:
  US13/953,583
• Publication Number:
  US 20140028110A1
• Time in Patent Office: 960 Days
• Field of Search: 307/104
• US Class Current: 1/1
• 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 transmit resonator coupled to a voltage source and a first impedance matching network; and

a receive resonator coupled to a second impedance matching network, the receive resonator being inductively coupled to the transmit resonator;

the system being 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.

5. The wireless power transfer system of claim 1, wherein the system is self-tuning and does not require an external control system to operate.

2. The wireless power transfer system of 1, wherein resonator tuning between the receiver and transmit resonators is optimized to keep a voltage gain within a specified range as the coupling coefficient varies.

3. The wireless power transfer system of 1, wherein resonator tuning between the receiver and transmit resonators is optimized to maximize efficiency over a given range.

4. The wireless power transfer system of 1, wherein resonator tuning between the receiver and transmit resonators is optimized to achieve a minimum amount of power transferred for a given source voltage.

6. A method of controlling a wireless power transfer system, comprising the steps of:

transmitting wireless power from a transmit resonator to a receive resonator; and

allowing resonant frequencies of the system to move towards an operating frequency of the system as a coupling coefficient between the transmit and receive resonators becomes smaller.

7. A wireless power transfer system, comprising:

a transmit resonator coupled to a voltage source and a first magnetic impedance matching network;

a receive resonator coupled to a second magnetic impedance matching network, the receive resonator being inductively coupled to the transmit resonator;

a transmit controller coupled to the first magnetic impedance matching network, the transmit controller configured to control a current in the first magnetic impedance matching network to generate a magnetic field in the transmit resonator; and

a receive controller coupled to the second magnetic impedance matching network, the receive controller 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.

8. The system of claim 7, wherein the DC load comprises a battery of an implantable medical device attached to the receive resonator.

9. The system of claim 8, wherein the current requested by the DC load is determined by a battery charge algorithm executed on the receive controller.

10. A method of controlling a wireless power transfer system, comprising the steps of:

transmitting wireless power from a transmit resonator to a receive resonator; and

controlling a current delivered to a DC load connected to the receive resonator 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.

11. A wireless power transfer system, comprising:

a transmit resonator coupled to a voltage source; and

a receive resonator inductively coupled to the transmit resonator and connected to a load with a rectifier circuit comprising a plurality of FETs, wherein the rectifier circuit acts as a controlled voltage source and is configured to tune resonant frequencies between the transmit resonator and the receive resonator.