100 MHz Wireless Power Transfer for Lightweight UAVs and Agile Robots

Wireless power transfer for lightweight unmanned aerial vehicles (UAV) and agile robots require relatively long transfer distances, tolerance to misalignment, light weight, and high power. In this paper, we show that operating at VHF (very-high-frequency) together with segmenting air-core coils using discrete capacitors and driving each segment separately is an effective method to achieve these goals. An active-to-passive segmented (APS) WPT system with eight primitive current-mode class D (CMCD) converters was demonstrated to operate at 100 MHz with 6W output power with 69% end-to-end drain (dc-dc) efficiency; 10W output power with 65% end-to-end drain (dc-dc) efficiency both at 4 cm transfer distance using an active segmented CMCD inverter and a passive segmented CMCD rectifier.