Small-signal Modeling of Lcc Resonant Converter

The small-signal modeling technique based on the extended describing function concept is applied to LCC resonant converters. The analytical model developed includes both frequency control and phase-shift control. The small-signal equivalent circuit models are also derived and implemented in PSPICE. The models are in good agreement with the measurement data. 1. INTRODUCTION An LCC resonant converter (Fig. 1) shares the advantages of other resonant converters, including natural commutation desirable for BJT, GTO and SCR devices when the switching frequency is lower than the resonant frequency, and zero voltage switching suitable for MOSFETs when the switching frequency is higher than the resonant frequency. These characteristics make the LCC resonant converter a potential candidate for high power or high frequency application. Besides the above features, the LCC resonant converter offers additional merits when compared with series resonant converters (SRCs) and parallel resonant converters (PRCs) [ l , 21. First, the series