An Implementation Method of Capacitive Power Transfer in Seawater Environments with Single-Wire Connection Using Seawater Ionic Conduction Effect

The strong ionic conduction of seawater creates a quasi-electrostatic shielding effect, leading to weak capacitive power transfer with the mutual coupling between capacitors suppressed. To achieve undersea capacitive power transfer (CPT), this letter proposes and introduces an implementation method using a single wire to connect two Y-type capacitors, thus constructing a dual-pathway system where seawater serves as second conductive channel. The single wire is designed to provide an additional conduction path for power loop, which guides current in the seawater to the receiver. The conductive principle of the method is first introduced, describing the power flow and the distribution of the displacement and conduction current. Then, a LC-CL compensated topology with single wire and Y-type capacitors is analyzed to obtain constant voltage output. Finally, an experimental prototype is built to verify the proposal. The results indicate the system can successfully transfer 2kW with 91% DC-DC efficiency to the load.