Half bridge LLC resonant converter with high voltage gain for single-phase AC/DC power system

This paper proposes a half bridge LLC resonant converter with high voltage gain employing Silicon Carbide (SiC) metal-oxide-semi-conductor field-effect transistor (MOSFET) for the DC/DC stage in the single-phase AC/DC power system. This converter is based on the switch integration techniques, which is merging the active-clamp forward (ACF) circuit and HB LLC resonant converter. The primary conduction loss can be significantly reduced by the high voltage gain. Although high voltage rating MOSFET is required, by applying high voltage rating SiC MOSFET with low channel resistance, the proposed converter can show high performance. Moreover, to asymmetric pulse width modulation (APWM), the optimal design for high efficiency can be achieved regardless the hold-up time and large ripple voltage. The validity of the proposed converter is confirmed by the experimental results of a prototype converter with 400VDC input and 800W (12V/65A) output.