Electromagnetic Model-Based Foreign Object Detection for Wireless Power Transfer

Foreign objects near wireless power transfer (WPT) systems are fire hazards that must be detected. In this paper, a new robust method is presented for foreign object detection based on an electromagnetic model for WPT. Foreign objects are detected by quantifying the deviation from a normal model. This deviation is caused by the foreign object's additional electromagnetic coupling. Advantages of this new method include invariance to power level allowing low-power tests prior to startup, receiver coil misalignment, and varying transmitting and receiver losses.