Small Signal Equivalent Circuit Modeling of Resonant Converters

A general analytical procedure is presented for the equivalent circuit modeling of resonant converters, using the series and parallel resonant converters as examples. The switched tank elements of a resonant converter are modeled by a lumped parameter equivalent circuit. The tank element circuit model consists in general of discrete energy states, but may be approximated by a low frequency continuous time model. These equivalent circuit models completely characterize the terminal behavior of the converters, and are solvable for any transfer function or impedance of interest. Closed form solutions are given for the equivalent circuit models of both converter examples, and the theoretical results are validated by experiment.