Efficient Method for Computing Capacitance Changes between Electrodes due to Foreign Objects in Capacitive WPT Systems

Abstract

In this paper, a foreign object detection method based on an integral formula is derived for capacitive wireless power transfer systems. The formula expresses the capacitance changes of the system and can predict even very small changes with high accuracy and computational efficiency, as the change is directly evaluated from the electric field in the volume of the foreign object. First, the derivation of the integral formula is presented, then a simple configuration is investigated using the finite element method.