RESONANT POWER TRANSFER SYSTEMS HAVING EFFICIENCY OPTIMIZATION BASED ON RECEIVER IMPEDANCE

• US 20170104369A1
• Filed: 10/06/2016
• Published: 04/13/2017
• Est. Priority Date: 10/07/2015
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Inventors: Petersen, Ethan Falk
• Granted Patent: US 10,177,604 B2
• Time in Patent Office: Days
• CPC Class Codes: A61M 2205/8243 by induction
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/873 specially adapted for wireless or transcutaneous energy transfer [TET], e.g. inductive charging
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

The present disclosure provides systems and methods for controlling wireless power transfer systems. A wireless power transfer system includes a transmitter driven by a power source and a transmit controller, wherein the transmitter is configured to control delivery of wireless power, and a receiver inductively coupled to the transmitter, the receiver configured to receive the wireless power from the transmitter and deliver the received wireless power to a load. The receiver includes receiver electronics configured to determine a Thevenin equivalent impedance of the wireless power transfer system, determine a Thevenin equivalent source voltage of the wireless power transfer system, and control, based on the determined Thevenin equivalent impedance and the determined Thevenin equivalent source voltage, an ideal source voltage of the receiver to vary the amount of the wireless power transferred from the transmitter to the receiver.

Claims

1. A wireless power transfer system comprising:

a transmitter driven by a power source and a transmit controller, wherein the transmitter is configured to control delivery of wireless power; and

a receiver inductively coupled to the transmitter, the receiver configured to receive the wireless power from the transmitter and deliver the received wireless power to a load, the receiver including receiver electronics configured to;

determine a Thevenin equivalent impedance of the wireless power transfer system;

determine a Thevenin equivalent source voltage of the wireless power transfer system; and

control, based on the determined Thevenin equivalent impedance and the determined Thevenin equivalent source voltage, an ideal source voltage of the receiver to vary the amount of the wireless power transferred from the transmitter to the receiver.

2. The wireless power transfer system of claim 1, wherein the receiver electronics are further configured to:

determine that the load requires additional power; and

transmit a control message to the transmitter that causes the transmitter to provide additional wireless power.

3. The wireless power transfer system of claim 1, wherein to control an ideal source voltage of the receiver, the receiver electronics are configured to:

compare Thevenin equivalent source voltage to the ideal source voltage; and

control the ideal source voltage based on the comparison.

4. The wireless power transfer system of claim 3, wherein to control the ideal source voltage based on the comparison, the receiver electronics are configured to increase the ideal source voltage when the Thevenin equivalent source voltage is greater than the ideal source voltage.

5. The wireless power transfer system of claim 3, wherein to control the ideal source voltage based on the comparison, the receiver electronics are configured to decrease the ideal source voltage when the Thevenin equivalent source voltage is less than the ideal source voltage.

6. The wireless power transfer system of claim 1, wherein to control an ideal source voltage of the receiver, the receiver electronics are configured to:

calculate a power limit voltage as a product of the Thevenin equivalent impedance and an ideal source current of the receiver; and

control the ideal source voltage such that the ideal source voltage is always less than or greater than the power limit voltage.

7. The wireless power transfer system of claim 6, wherein the receiver electronics are further configured to:

determine that a difference between the power limit voltage and the ideal source voltage is less than a predetermined value; and

transmit a control message to the transmitter that causes the transmitter to increase the Thevenin equivalent source voltage.

8. The wireless power transfer system of claim 1, wherein to determine a Thevenin equivalent impedance, the receiver electronics are configured to determine the Thevenin equivalent impedance by monitoring changes in an ideal source current of the receiver while varying the ideal source voltage.

9. A receiver for use in a wireless power transfer system, the receiver configured to receive wireless power from a transmitter driven by a power source and a transmit controller, and configured to deliver the received wireless power to a load, the receiver comprising:

a receiving coil; and

receiver electronics coupled to the receiving coil, the receiver electronics configured to;

determine a Thevenin equivalent impedance of the wireless power transfer system;

determine a Thevenin equivalent source voltage of the wireless power transfer system; and

control, based on the determined Thevenin equivalent impedance and the determined Thevenin equivalent source voltage, an ideal source voltage of the receiver to vary the amount of the wireless power transferred from the transmitter to the receiver.

10. The receiver of claim 9, wherein the receiver electronics are further configured to:

determine that the load requires additional power; and

transmit a control message to the transmitter that causes the transmitter to provide additional wireless power.

11. The receiver of claim 9, wherein to control an ideal source voltage of the receiver, the receiver electronics are configured to:

compare Thevenin equivalent source voltage to the ideal source voltage; and

control the ideal source voltage based on the comparison.

12. The receiver of claim 11, wherein to control the ideal source voltage based on the comparison, the receiver electronics are configured to increase the ideal source voltage when the Thevenin equivalent source voltage is greater than the ideal source voltage.

13. The receiver of claim 11, wherein to control the ideal source voltage based on the comparison, the receiver electronics are configured to decrease the ideal source voltage when the Thevenin equivalent source voltage is less than the ideal source voltage.

14. The receiver of claim 9, wherein to control an ideal source voltage of the receiver, the receiver electronics are configured to:

calculate a power limit voltage as a product of the Thevenin equivalent impedance and an ideal source current of the receiver; and

control the ideal source voltage such that the ideal source voltage is always less than or greater than the power limit voltage.

15. The receiver of claim 14, wherein the receiver electronics are further configured to:

determine that a difference between the power limit voltage and the ideal source voltage is less than a predetermined value; and

transmit a control message to the transmitter that causes the transmitter to increase the Thevenin equivalent source voltage.

16. The receiver of claim 9, wherein to determine a Thevenin equivalent impedance, the receiver electronics are configured to determine the Thevenin equivalent impedance by monitoring changes in an ideal source current of the receiver while varying the ideal source voltage.

17. A method for controlling a wireless power transfer system, the wireless power transfer system including a receiver inductively coupled to a transmitter, the receiver configured to receive wireless power from the transmitter and deliver the received wireless power to a load, the method comprising:

determining, using receiver electronics at the receiver, a Thevenin equivalent impedance of the wireless power transfer system;

determining, using the receiver electronics, a Thevenin equivalent source voltage of the wireless power transfer system; and

controlling, using the receiver electronics, based on the determined Thevenin equivalent impedance and the determined Thevenin equivalent source voltage, an ideal source voltage of the receiver to vary the amount of the wireless power transferred from the transmitter to the receiver.

18. The method of claim 17, further comprising:

determining that the load requires additional power; and

transmitting a control message to the transmitter that causes the transmitter to provide additional wireless power.

19. The method of claim 17, wherein controlling an ideal source voltage of the receiver comprises:

comparing Thevenin equivalent source voltage to the ideal source voltage; and

controlling the ideal source voltage based on the comparison.

20. The method of claim 17, wherein controlling an ideal source voltage of the receiver comprises:

calculating a power limit voltage as a product of the Thevenin equivalent impedance and an ideal source current of the receiver; and

controlling the ideal source voltage such that the ideal source voltage is always less than or greater than the power limit voltage.