Modified Resonant Z Circuit Analysis by Capacitive Power Transfer

Abstract

Capacitive type wireless power transfer systems, CPT, are becoming a suitable alternative to inductive type transfer systems. However, because their research is relatively recent, they have not achieved the power and efficiency levels of their inductive counterparts. To increase power with high efficiencies, feedback loops are used, but achieving adequate stability is problematic since the resonance frequency of this type of wireless system changes with respect to the distance of the capacitive plates, making it difficult to design the controller that could be used. In this work, the use of multi-resonant schemes to stabilize the resonance frequency is proposed. In particular, the analysis of the multi-resonant tank topology modified to compensate the frequency variation of a capacitive type energy transfer scheme is presented.