Study and Optimization of Shore-to-Ship Underwater Capacitive Power Transfer System Considering Parasitic Coupling

The increasing trend towards electrification in transportation highlights the potential for electric ships and the demand for safe, rapid charging systems. Underwater capacitive power transfer (UCPT) is considered a suitable solution due to its high power density potential. This article presents research on and optimization of UCPT for shore-to-ship charging in freshwater environments. It proposes a design for an insulation coupler and explores the influence of parasitic capacitance in the environment. This study demonstrates how the ship and shore impact the coupler’s coupling coefficient and mutual capacitance, thereby affecting the power and efficiency. Through theoretical calculations and finite element analysis, a kW-level UCPT coupler is designed. Experimental verification under different cases confirms the efficiency and constant current output characteristics, with superior performance observed when the coupler is positioned further away from the ship or shore. This study showcases the potential of UCPT to provide reliable and efficient power supply for electric ships, while emphasizing the importance of considering environmental factors and parasitic effects in system design and operation. These findings contribute to advancing UCPT technology and offer insights for further optimization to enhance practical applicability.