Design of a Capacitive Power Transfer System with Tolerance of Large Coupling Variations

This paper presents a new design methodology for capacitive power transfer (CPT) systems aimed at enhancing insensitivity to coupling variations. The designed CPT system maintains quasi-constant output power regardless of large coupling variations caused by misalignment. Its compensation network is designed to generate a constant current source. Design equations are derived for determining circuit parameters. The conditions and allowable range of the coupling variations are specified. Simulations and experimental results have demonstrated the validity of the proposed design method. A prototype CPT system has been built, capable of delivering up to 10W output power, with coupling changing from good alignment to 70mm longitudinal deviation.