Analysis of Eddy Current Loss and Frequency Optimization in Seawater WPT Systems with High Distance-Diameter Ratio

The wireless power transfer (WPT) technology is an effective way to solve the underwater equipment charging problem to achieve long-term continuous work. However, the presence of eddy current loss leads to a significant decrease in the efficiency of long-distance WPT in a seawater environment. Focusing on the efficiency problem of the seawater WPT system, this paper analyzes the principle of eddy-current loss first. Then, a 50 cm×50 cm coupler is simulated using HFSS finite element analysis software, with a distance of 50 cm. The relationship among eddy current loss, magnetic core, frequency, and coupler parameters is analyzed. At last, the total loss and efficiency of the system are derived based on the S-S compensation topology. At a frequency of 15kHz and transmitting 500W of power, the system efficiency is 87.365%, significantly improving the transmission efficiency under HDDR conditions in SWPT systems.