Analysis of Class-E LC Capacitive Power Transfer System

This paper presents the development of a new wireless power transfer technique using capacitive coupling. Capacitive power transfer (CPT) system has been introduced as an attractive alternative to the traditional inductive coupling method. This is due to the CPT benefits of simple topology, fewer components, better EMI performance and robustness to surrounding metallic elements. In this work, a Class-E inverter together with and without LC matching circuit has been utilized because of its ability to perform the dc-to-ac inversion efficiently with significant in switching losses. The validity of the proposed concept has been validated through simulation analysis using MATLAB Professional Software. The performance of the proposed topology are analysed in term of switching losses, input power, output power and dc-dc efficiency. Simulation results demonstrate that the system able to transfer 8.62W of power across 175pF capacitive interface, at an operating frequency of 1 MHz, with 93.4% efficiency for 0.25 mm coupling gap distance. With this topology, the zero voltage switching is able to be achieved even if the load is different by properly designing the LC matching transformation circuit.