Small-signal Modeling of a Series-Parallel Wireless Power Transfer System with Capacitive Output Filter Using Extended Describing Functions

In this paper, a small-signal model of a capacitive loaded series-parallel Wireless power transfer system is presented. Dynamic analysis of a series-parallel compensated wireless power transfer system with a capacitive output filter is illustrated based on extended describing function technique. Trial and error methods are still applied to this type of converters because of their ambiguous small-signal model. Since the small-signal model might experience a significant variation due to the load change, the trial and error procedure is not a reliable option. The proposed method provides a convenient option to obtain the small-signal model of the system which would lead to a systematic controller design. The precision of the derived model is verified by comparing it with the circuit simulation in open-loop and closed-loop modes of operation.