An Optimized Two-Module Capacitive Wireless Power Transfer System for EV Charging

This paper proposes a design optimization for a two-module capacitive wireless power transfer (CWPT) system for electric vehicle charging. Various spatial arrangements of the coupler plates in the two modules are considered and an optimized arrangement is chosen considering trade-offs among system efficiency, misalignment tolerance, and fringing electric field levels. An improved method is proposed to mitigate the adverse effects of inter-module parasitic capacitances considering the inherent asymmetries in the modules, enabling the modules to be effectively decoupled and designed independently. A 6.78-MHz 3.7-kW 15-cm air-gap two-module CWPT prototype designed based on the proposed optimization is built and tested at a scaled-down power level.