Separated Circular Capacitive Coupler for Reducing Cross-Coupling Capacitance in Drone Wireless Power Transfer System

Abstract

Capacitive power transfer (CPT) system can be employed for wireless charging of drone applications. However, in the CPT system, cross-coupling capacitance caused by coupling of the two pairs of plates on different sides, which do not form the main capacitance must be considered. Designs that do not properly consider the cross-coupling capacitance can cause decrease in the efficiency of the system. In this article, we propose a separate circular capacitive coupler for the CPT system. To reduce the cross-coupling capacitance in drone applications, the plates on the same side are separated. The circuit model of the coupler is presented; it considers a total of six coupling capacitances. For maximum power transfer efficiency, impedance of the receiver is considered to determine the parameter value of the LC resonance. Through simulation and measurement, we verified that the proposed separated circular coupler can reduce the cross-coupling capacitance. The plate-to-plate power transfer efficiency is maintained at 89.4% with 100-W output power.