Design of wireless power transfer system for autonomous underwater vehicles considering seawater eddy current loss

This paper presents a multi-objective design method of underwater wireless power transfer (UWPT) system for autonomous underwater vehicles (AUV) based on the cooperative design of compensation network and a DC/DC converter, considering seawater eddy current loss. Firstly, the electromagnetic field model of the underwater coil is established based on the non-axisymmetric model, and the analysis method of eddy current loss is given. Then, according to the circuit model with seawater eddy current loss, a two-port network including a compensation network and coil coupling model, is established. The cooperative design method of compensation network and DC/DC converter is presented to improve the efficiency of the UWPT system and reduce the electrical stress of the inverter, considering seawater eddy current loss. Finally, a 1 kW AUV UWPT system prototype is built. The experimental results prove that the proposed seawater eddy current loss analysis method is effective. The experimental results also show that the proposed compensation network and DC / DC converter duty cycle design method can achieve the purpose of constant voltage output, optimization of system efficiency, reduction of inverter electrical stress and inverter zero-voltage-switch.