Foreign object detection in wireless energy transfer systems

Patent metadata

Field	Value
Publication number	US-10686337-B2
Application number	US-201916277148-A
Country	US
Kind code	B2
Filing date	Feb 15, 2019
Priority date	Oct 19, 2012
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

The disclosure features apparatus, methods, and systems for wireless power transfer that include a power source featuring at least one resonator, a power receiver featuring at least one resonator, a first detector featuring one or more loops of conductive material and configured to generate an electrical signal based on a magnetic field between the power source and the power receiver, a second detector featuring conductive material, and control electronics coupled to the first and second detectors, where during operation, the control electronics are configured to measure the electrical signal of the first detector and compare the measured electrical signal of the first detector to baseline electrical information for the first detector to determine information about whether debris is positioned between the power source and the power receiver.

First claim

What is claimed is:

1. A wireless power transfer system, comprising:
an auxiliary coil positioned in proximity to at least one of a power source and a power receiver;
a detector positioned in proximity to at least one of the power source and the power receiver, wherein the detector is configured to generate an electrical signal in response to a change in a magnetic field; and
control electronics coupled to the auxiliary coil and to the detector, wherein the control electronics are configured to:
activate the auxiliary coil to generate a magnetic field at a position of the detector;
measure an electrical signal generated by the detector in response to the magnetic field generated by the auxiliary coil; and
determine whether debris is positioned in proximity to the at least one of the power source and the power receiver based on the measured electrical signal.

2. The system of claim 1 , wherein the control electronics are configured to:
activate at least one of the power source and the auxiliary coil to generate a second magnetic field at the position of the detector;
measure a second electrical signal generated by the detector in response to the second magnetic field; and
determine an extent of misalignment between the power source and the power receiver based on the second measured electrical signal.

3. The system of claim 1 , further comprising:
a first amplifier connected to the power source and configured to provide a first electrical driving signal to the power source; and
a second amplifier connected to the auxiliary coil and configured to provide a second electrical driving signal to the auxiliary coil.

4. The system of claim 1 , wherein the controller is configured to determine whether debris is positioned in proximity to the at least one of the power source and the power receiver by comparing the measured electrical signal to electrical baseline information.

5. The system of claim 4 , wherein the electrical baseline information comprises information about an electrical signal generated by the detector when no debris is positioned in proximity to the power source and to the power receiver.

6. The system of claim 4 , wherein comparing the measured electrical signal to electrical baseline information comprises determining mean and covariance matrices for the baseline information and determining whether debris is positioned in proximity to at least one of the power source and the power receiver based on the mean and covariance matrices.

7. The system of claim 6 , wherein the controller is configured to calculate a likelihood value, based on the mean and covariance matrices, that debris is positioned in proximity to at least one of the power source and the power receiver.

8. The system of claim 1 , wherein the detector is coupled to the power receiver.

9. The system of claim 1 , wherein the detector is positioned closer to the power receiver than to the power source.

10. The system of claim 1 , wherein the detector is coupled to the power source.

11. A method, comprising:
activating an auxiliary coil, separate from a power source and from a power receiver of a wireless power transfer system, to generate a magnetic field;
using a detector positioned in proximity to at least one of the power source and the power receiver to generate an electrical signal in response to a change in a magnetic field in proximity to the detector; and
determining whether debris is positioned in proximity to at least one of the power source and the power receiver based on the electrical signal.

12. The method of claim 11 , wherein the electrical signal is generated by the detector in response to a change in the magnetic field generated by the auxiliary coil.

13. The method of claim 11 , wherein the electrical signal is generated by the detector in response to a change in a magnetic field that is at least partially generated by the auxiliary coil.

14. The method of claim 11 , further comprising:
generating a second magnetic field in proximity to the detector;
generating a second electrical signal in response to the second magnetic field; and
determining an extent of misalignment between the power source and the power receiver based on the second electrical signal.

15. The method of claim 14 , further comprising activating the power source to generate the second magnetic field.

16. The method of claim 14 , further comprising activating the auxiliary coil to generate the second magnetic field.

17. The method of claim 11 , further comprising providing a first electrical driving signal to the power source from a first amplifier, and providing a second electrical driving signal to the auxiliary coil from a second amplifier that is different from the first amplifier.

18. The method of claim 11 , further comprising comparing the measured electrical signal to electrical baseline information to determine whether debris is positioned in proximity to the at least one of the power source and the power receiver.

19. The method of claim 18 , wherein the electrical baseline information comprises information about an electrical signal generated by the detector when no debris is positioned in proximity to the power source and to the power receiver.

20. The method of claim 18 , further comprising comparing the measured electrical signal to electrical baseline information by determining mean and covariance matrices for the baseline information, and determining whether debris is positioned in proximity to at least one of the power source and the power receiver based on the mean and covariance matrices.

21. The method of claim 20 , further comprising calculating a likelihood value, based on the mean and covariance matrices, that debris is positioned in proximity to at least one of the power source and the power receiver.

22. The method of claim 11 , wherein the detector is coupled to the power receiver.

23. The method of claim 11 , wherein the detector is positioned closer to the power receiver than to the power source.

24. The method of claim 11 , wherein the detector is coupled to the power source.

Assignees

• Witricity Corp

Inventors

• Roy Arunanshu Mohan
• Katz Noam
• Kurs Andre B
• Buenrostro Christopher
• Verghese Simon
• Kesler Morris P
• Hall Katherine L
• Lou Herbert Toby

Classifications

• H02J50/50

  using additional energy repeaters between transmitting devices and receiving devices · CPC title

• H02J50/90

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

• Y02T90/14

  Plug-in electric vehicles · CPC title

• Y02T90/12

  Electric charging stations · CPC title

• Y02T10/7072

  Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors · CPC title