Design of efficient matching networks for capacitive wireless power transfer systems

Abstract

High-power large air-gap capacitive wireless power transfer (WPT) systems require matching networks that provide large voltage or current gain and reactive compensation. This paper introduces an analytical optimization approach for the design of L-section multistage matching networks for capacitive WPT systems. The proposed approach maximizes the matching network efficiency and identifies the optimal distribution of gains and compensations among the L-section stages. The results of the proposed approach are validated using an exhaustive-search based numerical optimization for a 12-cm air-gap, 6.78-MHz, 125-W capacitive WPT system. A 6.78-MHz, 15-W prototype comprising a two-stage matching network is also designed using the proposed analytical approach and the theoretical predictions are validated experimentally.