Small-signal Impedance Model of an Inductive Power Transfer System Using LCC-LCC Compensation

Unregulated inductive power transfer systems are widely adopted for wireless charging scenarios. Such a system is usually cascaded with a dc/dc converter for input or output regulation. The overall system stability needs an in-depth study of the terminal impedance from the small signal perspective. This paper focuses on the impedance model of an LCC-LCC compensated system. An equivalent circuit model is built and used to explicitly derive the input and output impedance. The experiment results show that the model is simple and accurate up to 1/5 of the switching frequency.