A novel generalized sampled-data dynamic model for a series-parallel resonant converter under self-sustained oscillation mode. Part I: capacitive output filter

Mohamed Z. Youssef^* and Praveen K. Jain:

A novel analytical sampled data dynamic model for a series-parallel resonant converter with capacitive output filter operating in self-sustai-ned oscillation mode (SSOC) is presented. Generalized state-space small-signal and large-signal models, which include the high frequency effects such as leakage inductance of the transformer and series equivalent resistance of the output filter capacitor, are derived for the first time to study the behavior under any loading condition and operating frequency. Finally, numerical solution, simulation results, and experimental results are addressed to verify the proposed methodology. It is shown that the series-parallel converter with capacitive output filter has better transient response than the converter with the inductive-capacitive output filter. The presented modeling technique will be useful in designing the resonant power supplies for low voltage and high current applications with very fast load transient requirement.