Hybrid foreign object detection (FOD) loop array board

• US 10,124,687 B2
• Filed: 09/14/2016
• Issued: 11/13/2018
• Est. Priority Date: 09/14/2016
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: Qualcomm, Inc.
• Inventors: Percebon, Leandro, Kuerschner, Daniel
• Primary Examiner(s): Memula, Suresh
• Application Number:
  US15/264,908
• Publication Number:
  US 20180072166A1
• Time in Patent Office: 790 Days
• Field of Search: 320108
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Techniques for detecting a presence of a metallic and/or a ferromagnetic object over a region for wirelessly transferring power to charge an electric vehicle are presented. An example apparatus includes one or more foreign object detection (FOD) loops arranged in an array over a charging area, at least a portion of the FOD loops being in a first configuration and at least a portion of the FOD loops being second configuration different than the first configuration based on a value indicative of an amount of magnetic coupling between the charging area and a respective one the FOD loops within a corresponding area of the array.

Claims

1. An apparatus for detecting a presence of a metallic or a ferromagnetic object over a region for wirelessly transferring power to charge an electric vehicle, the apparatus comprising:

a plurality of foreign object detection (FOD) loops arranged in an array over a charging area, at least a portion of the plurality of FOD loops being in a first configuration and at least a portion of the plurality of FOD loops being in a second configuration different than the first configuration based on a value indicative of an amount of magnetic coupling between one or more charging coils in the charging area and a respective one the plurality of FOD loops within a corresponding area of the array, wherein a difference between the first configuration and the second configuration corresponds to a difference in a magnetic flux direction of the respective portions of FOD loops.

2. The apparatus of claim 1 wherein the amount of magnetic coupling is based on an operating frequency of the one or more charging coils in the charging area.

3. The apparatus of claim 1 wherein the charging area includes one or more areas with a first magnetic flux direction and one or more areas with a second magnetic flux direction different from the first magnetic flux direction.

4. The apparatus of claim 3 wherein the at least a portion of the plurality of FOD loops being in the first configuration are disposed over the one or more areas with the first magnetic flux direction, and the at least a portion of the plurality of FOD loops being in the second configuration are disposed over the one or more areas with the second magnetic flux direction.

5. The apparatus of claim 1 wherein the first configuration is a circular loop and the second configuration is a double loop.

6. The apparatus of claim 5 wherein the double loop is wound with a figure-eight configuration.

7. The apparatus of claim 5 wherein the second configuration is a double loop orientated along an x-axis or a double loop oriented along a y-axis.

8. The apparatus of claim 5 wherein the second configuration is a double loop oriented along a diagonal axis oriented between an x-axis and a y-axis.

9. The apparatus of claim 1 further comprising a control circuit operably coupled to each of the plurality of FOD loops and configured to drive each of the plurality of FOD loops at a first frequency that is different from an operating frequency of the one or more charging coils in the charging area to generate a magnetic field, and to detect the metallic or the ferromagnetic object based on an electrical characteristic in one or more of the plurality of FOD loops caused by the metallic or the ferromagnetic object coupling with the magnetic field.

10. The apparatus of claim 9 wherein the electrical characteristic is a voltage amplitude value.

11. The apparatus of claim 9 wherein the electrical characteristic is a phase measurement.

12. The apparatus of claim 9 wherein the control circuit is configured to reduce a charging operation based on the electrical characteristic in one or more of the plurality of FOD loops.

13. A method of detecting foreign objects in a wireless power transfer system, comprising:

determining a foreign object detection (FOD) array dimension, wherein the FOD array comprises a plurality of FOD loop elements disposed over one or more primary charging coils in the wireless power transfer system;

determining one or more FOD loop configurations for each of the plurality of FOD loop elements, wherein the one or more FOD loop configurations include a circular loop and a double loop;

determining a FOD loop orientation for each of the one or more FOD loop configurations in each of the plurality of FOD loop elements; and

selecting a FOD loop configurations and the FOD loop orientation for each of the plurality of FOD loop elements based on a magnetic coupling to the one or more primary charging coils.

14. An apparatus for wirelessly transferring power to charge an electric vehicle, comprising:

a primary charging coil in a double-D (DD) configuration configured to operate at a first frequency;

a plurality of foreign object detection (FOD) loops arranged in an array over the primary charging coil, at least a portion of the plurality of FOD loops being in a first configuration and at least a portion of the plurality of FOD loops being a second configuration that is different than the first configuration, wherein a difference between the first configuration and the second configuration corresponds to a magnetic flux direction of the respective at least a portion of the plurality of FOD loops; and

a control circuit operably coupled to the primary charging coil and the plurality of FOD loops, and configured to drive the plurality of FOD loops at a second frequency that is different from the first frequency to generate a magnetic field, and to detect a foreign object based on an electrical characteristic in at least one of the plurality of FOD loops caused by the foreign object coupling with the magnetic field.

15. The apparatus of claim 14 wherein the first configuration is a circular loop and the second configuration is a double loop.

16. The apparatus of claim 14 wherein the primary charging coil includes one or more areas with a first magnetic flux direction and one or more areas with a second magnetic flux direction different from the first magnetic flux direction.

17. The apparatus of claim 16 wherein the at least a portion of the plurality of FOD loops being in the first configuration are disposed over the one or more areas with the first magnetic flux direction, and the at least a portion of the plurality of FOD loops being in the second configuration are disposed over the one or more areas with the second magnetic flux direction.

18. The apparatus of claim 14 wherein the second configuration is a double loop oriented along a diagonal axis oriented between an x-axis and a y-axis.

19. The apparatus of claim 14 wherein the electrical characteristic is at least one of a voltage amplitude value or a phase measurement.

20. The apparatus of claim 14 wherein the control circuit is configured to reduce a transfer of power to the electric vehicle based on the electrical characteristic in one or more of the plurality of FOD loops.

21. The apparatus of claim 14 wherein the first frequency is in a range from 80-90 kHz.

22. The apparatus of claim 14 wherein the second frequency is in a range from 1-10 MHz.

23. An apparatus for wirelessly transferring power to charge an electric vehicle, comprising:

a primary charging means for providing power to the electric vehicle at a first frequency;

detection means for detecting foreign objects, the detection means arranged in an array over the primary charging means, at least a portion of the detection means being in a first configuration and at least a portion of the detection means being a second configuration that is different than the first configuration, wherein a difference between the first configuration and the second configuration corresponds to a magnetic flux direction of the respective at least a portion of the detection means; and

a control means operably coupled to the detection means and configured to drive the detection means at a second frequency that is different from the first frequency to generate a magnetic field, and to detect a foreign object based on an electrical characteristic in the detection means caused by the foreign object coupling with the magnetic field.

24. The apparatus of claim 23 wherein the control means is operably coupled to the primary charging means and configured to reduce a transfer of power to the electric vehicle based on the electrical characteristic in the detection means.