Interleaved Reconfigurable-Bridge LLC Resonant Converter with Ultrawide Voltage Range

This paper proposes an interleaved reconfigurable-bridge LLC resonant converter for wide output voltage range applications. The converter is reconfigurable through different switching patterns depending on the output voltage conditions, achieving four operation modes: bridge change, effective turns ratio adjustment, and phase shift of the primary-and secondary-side switches. Therefore, the output voltage gain is significantly expanded while achieving a narrow switching frequency range. This allows for selection of an appropriate magnetizing inductance, and significantly reduces circulating current and conduction losses. It also reduces voltage and current stress by achieving zero-voltage switching of the MOSFETs at full load. To verify the performance of the proposed converter, a 3.3 kW rated converter with 400 V input and 150 V-1000 V output is designed.