Optimized Design of High-Efficiency Immittance Matching Networks for Capacitive Wireless Power Transfer Systems

This paper introduces an analytical approach to optimize the design of immittance matching networks that provide gain and reactive compensation in capacitive wireless power transfer (WPT) systems while maintaining load-independent output current. The proposed approach maximizes the matching network efficiency by identifying the optimal number of matching network stages, and by optimally distributing the overall gain among these stages. Compared to the conventional approach to designing immittance matching networks in capacitive WPT systems, the proposed approach is shown to achieve 82% smaller losses. A 6.78-MHz capacitive WPT prototype utilizing immittance matching networks is designed and built, and the measured network efficiency is shown to match well with analytical predictions.