Foreign Object Detection In Wireless Energy Transfer Systems

Abstract

The disclosure features wireless energy transfer systems that include a plurality of sensors coupled to a controller, wherein the controller is configured to: obtain a system calibration state including a set of basis vectors derived from a first set of electrical signals generated by the plurality of sensors with no foreign object debris in proximity to the system; measure a second set of electrical signals from the sensors; calculate a projection of the second set of electrical signals onto the set of basis vectors; calculate a detection signal based on the projection; determine whether foreign object debris is present in proximity to the system by comparing the calculated detection signal to a detection threshold value; and adjust the system calibration state based on the presence or absence of foreign object debris in proximity to the system to generate an updated system calibration state.

What is claimed is: 
     
         1 . A wireless energy transfer system, comprising:
 a source resonator configured to generate an oscillating magnetic field to transfer energy to a receiver resonator;   a plurality of sensors, wherein each of the sensors is configured to generate an electrical signal in response to a magnetic field; and   a controller coupled to each of the sensors,   wherein during operation of the system, the controller is configured to:
 obtain a system calibration state comprising a set of basis vectors derived from a first set of electrical signals generated by the plurality of sensors with no foreign object debris in proximity to the system; 
 measure a second set of electrical signals generated by the plurality of sensors; 
 calculate a projection of the second set of electrical signals onto the set of basis vectors; 
 calculate a detection signal based on the projection of the second set of electrical signals; 
 determine whether foreign object debris is present in proximity to the system by comparing the calculated detection signal to a detection threshold value; and 
 adjust the system calibration state based on the presence or absence of foreign object debris in proximity to the system to generate an updated system calibration state.