Wireless battery charging system for drones via capacitive power transfer

Abstract

We developed the wireless battery charging system for an unmanned aerial vehicle (UAV) or a drone using the capacitive power transfer (CPT) technology which provides a wide charging area for the drone to land especially required at autonomous flying. As the circuit on the power receiving side or drone side must be small and light in this application, we employ the circuit where a matching circuit, a transformer and all inductors are placed in the emitting side and the circuit in the receiving side is composed of the small devices using semiconductor elements for DC-DC converter and charge controlling IC. The system validity has been verified with prototype that delivered ~12W through a combined interface capacitance of 500 pf at an operating frequency 6.78MHz and efficiency exceeding 50%.