This paper proposes a wireless power transfer (WPT) system with quasi-uniform magnetic coupling to satisfy the Unmanned Aerial Vehicle (UAV) lightweight constant current (CC) charging without secondary feedback control. The traditional wired charging for UAVs is less automated and not portable. WPT as a new way of energy supply has shown great potential for charging UAVs with safety and automation. However, some actual challenges still exist due to the UAV's special structure and lightweight requirements. Accordingly, a coupler with a lightweight receiving coil and double transmitting coils to satisfy the CC wireless charge of the UAV without communication and control is proposed in this paper. The power transfer and CC charging theory analysis are carried out, and the structure of the coupler is designed. A simulation model and a prototype are built, as well as the simulation and experimental results are given to verify the performance of the proposed UAV CC charging system. In the experiment, 23.8 Wh of power is charged to the UAV's lithium battery pack with CC in two hours. This paper provides a reference to the design of the UAV wireless charging stations.

Inductively coupled power transfer (ICPT) is a new technology used in mooring buoy for underwater sensors power supply. In this paper, an ICPT system with a mooring cable to power double ultracapacitor chargers is proposed. Firstly, the system model is analyzed in detail, including the primary side of abovewater system, the mooring cable, and the secondary side of underwater system. Secondly, to reduce the torque between buoy and mooring cable, a non-contact rotary magnetic coupler, which can provide two degrees of freedom, is designed. Thirdly, considering that the charging voltage is difficult to feedback directly, indirect closed-loop control using current in the mooring cable is applied to achieve constant current and voltage charging. Finally, the proposed analyses are verified in experiments. As gap of the abovewater magnetic coupler changes, two ultracapacitor modules are charged in 1A, and the maximum efficiency is 65.75% respectively.