Derivation and Comparison of Efficiency and Power in Non-resonant and Resonant Circuit of Capacitive Power Transfer

Capacitive Power Transfer (CPT) is safer than Inductive Power Transfer (IPT), because eddy current is not generated in CPT. In this study, conditions for transfer with high efficiency and high power were presented by deriving equation of the resonance conditions, efficiency, power, and optimal load considering internal resistance in non-resonance (N-N), primary resonance (S-N), secondary resonance (N-S), series-series (S-S) and series-parallel (S-P) without approximation. In addition, the value of efficiency and power are derived and compared in the five topologies. As a result, it is said that S-S can transfer 95W output power with 95% efficiency and S-S can transfer 98W output power with 95% efficiency when input voltage is 100V. And, S-S and S-P are superior to other three topologies. Furthermore, the validity of the results was shown by conducting experiments.