Analysis and Design of LCC Resonant Converter with Capacitive Filter for Wide Output Voltage Range Applications

An unfolder circuit-based DC-AC power conversion system requires the DC-DC stage to produce a wide range of output voltages. This paper evaluates the feasibility of employing an LCC resonant converter with a capacitive filter (LCC-CF) in such applications. The LCC-CF converter design uses a switching frequency modulation technique, which enables the generation of a wide output voltage range ($67 \mathrm{~V}-392 \mathrm{~V}$) from a 28 V DC source under varying load conditions. The proposed design approach guarantees zero-voltage switching (ZVS) in the primary-side halfbridge MOSFETs across the entire output voltage and load range. The design is validated through PLECS simulation and experimental results from a 70 W LCC-CF hardware prototype.