Conductive Coupler for Wireless Power Transfer Under Seawater

This paper presents a coupler consisting of two pairs of parallel-plate electrodes for wireless power transfer (WPT) under seawater. The paper clarifies two points. One is the operational principle of our conductive coupler using a simplified equivalent circuit. The crucial parameters for the design are based on a theoretical equation to obtain maximum available efficiency. The other is to clarify the power transfer efficiency via a demonstration of the WPT. A design method using an electromagnetic (EM) simulation is introduced and the prototype is manufactured. Results showed that the maximum available efficiency of 79 % at 2 MHz from the measured results could be achieved. Furthermore, power transfer efficiency of about 50 % at 6.78 MHz was maintained at around a input power of 275 W.