Analysis and Design of Undersea Capacitive Power Transfer with Constant Voltage Output for Multiple Loads

Seawater capacitive power transfer (SCPT) technology has the advantages of low weight, long transmission distance and no eddy current loss, which has great potential in the power supply of underwater equipment. This paper proposes a single input and multiple output (SIMO)-SCPT with single wire, which has constant voltage (CV) output characteristic. Firstly, the diode conduction situation in one cycle in resonant and non-resonant conditions is analyzed, and equivalent circuits under two normal modes are drawn. Secondly, multi-load CV output design goals based on dual-mode are proposed, and second/third order compensated full impedance models are established. The feasibility of third-order compensation network to eliminate DC bias is analyzed, and all second-order compensation topologies that can realize multi-load CV output are summarized. Finally, a dual-load SCPT experimental device with a total output power of 476W is built, which can achieve multi-load CV output in seawater, and the input power is automatically adjusted in multiples according to the change in the number of loads.