Wireless power delivery in dynamic environments

Patent metadata

Field	Value
Publication number	US-11090481-B2
Application number	US-201916358528-A
Country	US
Kind code	B2
Filing date	Mar 19, 2019
Priority date	May 21, 2012
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

An adaptive system for efficient and long-range wireless power delivery using magnetically coupled resonators responds to changes in a dynamic environment, and maintains high efficiency over a narrow or fixed frequency range. The system uses adaptive impedance matching to maintain high efficiency. The wireless power transfer system includes a drive inductor coupled to a high-Q transmitter coil, and a load inductor coupled to a high-Q receiver coil. The transmitter coil and receiver coil for a magnetically coupled resonator. A first matching network is (i) operably coupled to the drive inductor and configured to selectively adjust the impedance between the drive inductor and the transmitter coil, or (ii) is operably coupled to the load inductor and configured to selectively adjust the impedance between the load inductor and the receiver coil.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An adaptive impedance matching wireless power transfer system comprising:
a drive inductor configured to receive alternating current electric power from a power source at a fixed frequency;
a high quality factor (“high-Q”) transmitter coil inductively coupled to the drive inductor;
a high-Q receiver coil configured to be inductively coupled to the transmitter coil; and
a load inductor inductively coupled to the receiver coil;
a first impedance matching network comprising a plurality of capacitors that are (i) operably coupled to the drive inductor and configured to selectively adjust the impedance between the drive inductor and the transmitter coil, or (ii) are operably coupled to the load inductor and configured to selectively adjust the impedance between the load inductor and the receiver coil;
a switching circuit comprising a microcontroller operably connected to a plurality of sub-circuits, wherein each of the plurality of sub-circuits engage an associated one of the plurality of capacitors to operably engage or disengage the associated one of the plurality of capacitors;
wherein each sub-circuit comprises:
a pair of back to back field effect transistors that connect the associated capacitor to a ground, and a gate driver operatively controlled by the microprocessor and configured to selectively switch the field effect transistors between an open state, and a closed state, each gate driver comprising:
a resistor connected to gates of the pair of back to back field effect transistors,
a transistor of the gate driver, and
a diode connected to the resistor and to the gates of the pair of back to back field effect transistors on one side and connected to the transistor of the gate driver on the other side, wherein the diode is connected to ground when transistor of the gate driver is turned ON;

and wherein the microcontroller is configured to receive a measured operating parameter of the adaptive impedance matching wireless power transfer system and to use the measured operating parameter to selectively adjust the impedance between the drive inductor and the transmitter coil or selectively adjust the impedance between the load inductor and the receiver coil.

2. The system of claim 1 , wherein the drive inductor forms a portion of the first impedance matching network.

3. The system of claim 1 , wherein the load inductor comprises a single loop.

4. The system of claim 1 , wherein the first impedance matching network comprises a first π-match network.

5. The system of claim 1 , wherein the microcontroller is controlled to selectively adjust the impedance to achieve a capacitance that maximizes the forward transmission gain to the transmitter coil.

6. The system of claim 1 , wherein the microcontroller exhaustively engages each combination of the plurality of capacitors to produce an optimal power transfer.

7. The system of claim 1 , wherein the microcontroller uses the measured operating parameter with a lookup table to selectively adjust the impedance.

8. The system of claim 1 , wherein the microcontroller monitors a measured performance parameter of the system and uses the measured performance parameter to selectively adjust the impedance.

9. The system of claim 1 , wherein the microcontroller monitors more than one measured operating parameters of the system, and calculates an optimal capacitance based on the measured operating parameters.

10. The system of claim 1 , wherein the at least one switchable bank of capacitors comprises at least five capacitors.

11. The system of claim 1 , further comprising a second impedance matching network that is operable to selectively adjust the impedance between the receiver coil and the load inductor.

12. The system of claim 11 , wherein the load inductor forms a portion of the second impedance matching network.

13. The system of claim 11 , wherein the first impedance matching network comprises a first π-match network with variable capacitances and the second impedance matching network comprises a second n-match network with variable capacitances.

14. The system of claim 1 , further comprising a rectifier configured to receive alternating current from the load coil, an active impedance matching circuit configured to receive direct current from the rectifier, and a microcontroller configured to monitor the direct current from the rectifier and to control the active impedance matching circuit to selectively harvest power from the rectifier and provide power to a device.

15. The system of claim 14 , wherein the active impedance matching circuit comprises a buck converter.

16. The system of claim 15 , wherein the microcontroller selectively adjusts the buck converter.

17. The system of claim 1 , wherein the first impedance matching network comprises a first π-match network.

18. The system of claim 1 , wherein the measured operating parameter comprises an S-parameter or an RMS voltage measured in the system.

Assignees

• Univ Washington Through Its Center For Commercialization

Inventors

• Smith Joshua R
• Waters Benjamin H
• Wisdom Scott
• Sample Alanson P

Classifications

• H02J50/90 Primary

  involving detection or optimisation of position, e.g. alignment · CPC title

• A61M60/216 Primary

  including a rotating member acting on the blood, e.g. impeller · CPC title

• A61M60/873

  specially adapted for wireless or transcutaneous energy transfer [TET], e.g. inductive charging · CPC title

• A61M60/538

  Regulation using real-time blood pump operational parameter data, e.g. motor current · CPC title

• A61M60/523

  using blood flow data, e.g. from blood flow transducers · CPC title