Recently, with the widespread application of UAVs in multiple fields, a single UAV can no longer meet complex tasks, and UAV cluster that collaborate to complete tasks are becoming increasingly popular. Wireless power transfer (WPT) technology provides a reliable and safe power supply/charging way/approach that could effectively improving the endurance of UAV clusters/UAVs. In this paper, a multiload WPT system with constant current/voltage (CC/CV) charging mode based on LCC-S topology for UAV clusters is proposed. Theoretical analysis is derived the method for implementing CC and CV charging mode in the proposed system, which can be achieved by switching the operating frequency of the system. Besides, a transmitter coil with uniform magnetic field distribution is designed in this manuscript, which can effectively guarantee that each UAV in the cluster receives the equivalent power. Subsequently, a WPT charging platform suitable for two UAVs is established. the experimental results show that the proposed WPT system can concurrently supply power to all UAVs, while the two UAVs could simultaneously achieve CC and CV charging modes. The experimental results show that the proposed WPT system can concurrently supply power to two UAVs, while the two UAVs could simultaneously achieve CC and CV charging modes independent of load resistance variations. The fluctuation percentage of charging current and voltage with load resistance change in CC and CV modes can be maintained below 4.5% and 5.2%, respectively.

wireless power transfer (WPT); constant current charging; constant voltage charging; unmanned ariel vehicle (UAV)