Foreign object detection in wireless energy transfer systems
View Patent ↗A wireless energy transfer system includes a foreign object debris detection system. The system includes at least one wireless energy transfer source configured to generate an oscillating magnetic field. The foreign object debris may be detected by at least one field gradiometer positioned in the oscillating magnetic field. The voltage of the at least one field gradiometer may be measured using readout circuitry and a feedback loop based on the readings from the gradiometers may be used to control the parameters of the wireless energy source.
1. A wireless energy transfer system with foreign object debris detection, the system comprising:
a wireless energy transfer source comprising a source resonator configured to generate an oscillating magnetic field; and
a foreign object debris detection system comprising:
at least one magnetic field sensor; and
at least one readout circuit configured to measure one or more electrical parameters of at the at least one magnetic field sensor,
wherein the at least one magnetic field sensor is positioned within the magnetic field of the wireless energy transfer system; and
wherein the foreign object debris detection system is configured to verify that foreign object debris has not moved onto or over the source resonator during generation of the oscillating magnetic field.
2. The system of claim 1 , wherein the wireless energy transfer source is configured to generate the oscillating magnetic field to transfer energy to a vehicle.
3. The system of claim 2 , wherein the foreign object debris detection system is configured to verify that foreign object debris has not moved onto or over the source resonator prior to a transfer of energy from the source resonator to the vehicle.
4. The system of claim 3 , wherein the foreign object debris detection system is configured to perform a health and/or status check of the wireless energy transfer source before the vehicle is positioned over the source resonator.
5. The system of claim 4 , wherein the foreign object debris detection system is configured to perform the health and/or status check less frequently than the verification that foreign object debris has not moved onto or over the source resonator prior to a transfer of energy from the source resonator to the vehicle.
6. The system of claim 4 , wherein the foreign object debris detection system is configured to periodically perform the health and/or status check and the verification that foreign object debris has not moved onto or over the source resonator prior to a transfer of energy from the source resonator to the vehicle.
7. The system of claim 2 , wherein the foreign object debris detection system is configured to verify that foreign object debris has not moved onto or over the source resonator after the vehicle is positioned over the source resonator and prior to a transfer of energy from the source resonator to the vehicle.
8. The system of claim 1 , wherein the foreign object debris detection system is configured to verify that foreign object debris has not moved onto or over the source resonator prior to generation of the oscillating magnetic field.
9. The system of claim 1 , wherein the wireless energy transfer source is a component of a vehicle charging station.
10. The system of claim 9 , further comprising a device module configured to be mounted on an electric vehicle.
11. The system of claim 1 , wherein the foreign object debris detection system is integrated into the wireless energy transfer source.
12. The system of claim 1 , further comprising an enclosure housing at least a portion of the wireless energy transfer source, wherein the foreign object debris detection system is integrated into the enclosure.
13. The system of claim 1 , wherein the wireless energy transfer source is configured to deliver a power of more than 3.3 kW to a wireless power receiving device.
14. The system of claim 1 , wherein:
the at least one magnetic field sensor comprises a first conductive loop and a second conductive loop having a maximum dimension larger than a maximum dimension of the first conductive loop;
the first conductive loop is positioned in a first spatial region and the second conductive loop is positioned in a second spatial region different from the first spatial region; and
an amplitude of the oscillating magnetic field in the first spatial region is larger than an amplitude of the oscillating magnetic field in the second spatial region.
15. The system of claim 1 , wherein:
the at least one magnetic field sensor comprises a first conductive loop and a second conductive loop having a maximum dimension larger than a maximum dimension of the first conductive loop;
the first conductive loop is positioned in a first spatial region and the second conductive loop is positioned in a second spatial region different from the first spatial region; and
a spatial variation of the oscillating magnetic field in the first spatial region is larger than a spatial variation of the oscillating magnetic field in the second spatial region.
16. A method of detecting foreign object debris in a wireless energy transfer system, the method comprising:
performing a health and/or status check of a source resonator of the wireless energy transfer system;
verifying that no foreign object debris has moved onto or over the source resonator;
positioning a vehicle over the source resonator;
verifying that no foreign object debris has moved onto or over the source resonator;
generating an oscillating magnetic field using the source resonator to transfer energy wirelessly to the vehicle to charge a battery of the vehicle; and
verifying that no foreign object debris has moved onto or over the source resonator during the transfer of energy.