Series–Parallel Resonant Converter in Self-Sustained Oscillation Mode With the High-Frequency Transformer-Leakage-Inductance Effect: Analysis, Modeling, and Design

An accurate modeling of the series-parallel resonant converter operating in self-sustained oscillation mode including the overlap effects of the output rectifying stage due to the leakage inductance of the transformer is presented. This paper presents a systematic procedure to study the aforementioned effects on the converter dynamic and steady-state performance. Such information is critical in designing isolated high-frequency resonance-based voltage-regulator modules for powering future subvoltage very large scale integration circuits such as microprocessors. The extended describing function technique is used to extract the steady-state characteristics in order to get an optimum converter design. Averaging state-space techniques are employed to derive a small-signal model that can describe the converter dynamics accurately. Analytical and simulation results are given. Finally, a 1-kW experimental prototype is built to verify the validity of the proposed work