A Free-Positioning and Compact Unmanned Aerial Vehicle Wireless Charging System Based on Two-Stage Energy Peak-to-Valley Matching Output Fluctuation Suppression

This paper proposes a wireless charging system for unmanned aerial vehicles (UAVs) that achieves high tolerance to misalignment through a novel two-stage energy matching technique. In the first stage, the orthogonal receiving coils within each receiver capture complementary horizontal and vertical magnetic flux components generated by reverse-series transmitting coils, achieving magnetic energy peak-to-valley matching through rectification and superposition, effectively eliminating energy dead zones. In the second stage, the outputs of two receivers are combined to achieve electrical energy matching, effectively reducing output fluctuations and enhancing system efficiency. The design incorporates a mode-switching strategy and fundamental wave analysis to meet power transmission and charging control requirements. Experimental results demonstrate that the system can deliver a constant current of approximately 6.1 A with a consistent DC-DC efficiency of 82.2%. Within a deviation range of ±90 mm, the output efficiency fluctuation is limited to 4.57%, and with varying angular misalignment, the output current fluctuation is only 0.98%. This indicates the system's high effectiveness in UAV wireless charging, even under misaligned conditions. The proposed approach provides a valuable technical reference for the engineering deployment of UAV wireless charging systems.