Null-free two-dimensional capacitive wireless power transfer based on inversion of electric field distribution

Abstract

One of the crucial challenges of capacitive two-dimensional wireless power transfer (2-D WPT) is the variation in transfer efficiency depending on the RX position. In this paper, we suppress this variation using an inversion of the electric field distribution. First, we analyze the E-field distribution on a comb-like TX electrode for use in capacitive 2-D WPT. The null points are generated on the comb-like electrode, and their positions are identified by deriving the input admittance. Then, we confirm that they are inverted by open-/short-termination switching. Finally, the variation in the power transfer efficiency is suppressed by switching the termination condition.