A Bidirectional Wireless Charging System for Unmanned Aerial Vehicles With Emergency Power Supply Capability

ABSTRACT The bidirectional wireless power transfer (WPT) system not only recharges the inspection unmanned aerial vehicles (UAVs) but also allows the UAVs to serve as an emergency power supply for electrical devices within the charging station. However, most existing bidirectional WPT systems are proposed for electric vehicles and do not meet the requirements of the lightweight design of UAVs. A novel bidirectional WPT system with low control complexity is proposed in this paper, which achieves inherent constant current (CC) to constant voltage (CV) transition during the charging process and CV output during the discharge process. The detailed analysis of the bidirectional operating mode is provided. The asymmetric coil structure is designed to minimize the impact of UAVs landing misalignment. Furthermore, eliminating ferrites on the UAV side helps reduce the weight of the UAVs. The series capacitor compensation on the UAV side enables the use of a half‐bridge converter configuration to reduce the cost of UAVs. The parameter design process, complemented by a sensitivity analysis, is employed to ensure that the system achieves both near zero phase angle (ZPA) and zero voltage switching (ZVS). Finally, an experimental prototype with 96 V input and 48 V/3 A output in charging mode, and 48 V input and 96 V output in discharge mode is built to verify the correctness and feasibility of the proposed bidirectional WPT system. The maximum efficiencies of 90.2% and 90.3% are obtained in the charging mode and discharge mode, respectively.