An Inductive and Capacitive Integrated Coupler and Its LCL Compensation Circuit Design for Wireless Power Transfer

This paper proposes a novel coupler structure for wireless power transfer, which takes advantage of both magnetic and electric fields. The coupler contains four metal structures, two each at the primary and secondary sides, which are capacitively coupled. Each structure consists of long strips of metal sheet to increase its self-inductance, which is then inductively coupled with the other three structures. The structures are vertically arranged and the outer structures are larger than the inner ones to maintain the capacitive couplings. An external LCL compensation network is proposed to resonate with the coupler. The resonance provides conduction currents flowing through each plate to establish magnetic fields and displacement currents flowing between different plates corresponding to electric fields. A 100-W output power prototype is designed and implemented to operate at 1.0 MHz, and it achieves 73.6% efficiency from dc source to dc load across an air-gap distance of 18 mm. The contribution of this paper is to propose a concept to transfer power using magnetic and electric fields simultaneously.