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 ηmax. The other is to clarify the power transfer efficiency η via a demonstration of the WPT. A design method using an electromagnetic (EM) simulation is introduced and the prototype is manufactured. Results showed that ηmax of 79% at 2 MHz from the measured results could be achieved. Furthermore, η of about 50% at 6.78 MHz was maintained at around an input power of 275 W.