A Wide-Input-Range Current-Fed Resonant DC-DC Converter With Triple-Mode Operation for Fuel-Cell Vehicles

Conventional current-fed converters have limitations to accommodate a wide voltage range of fuel-cell stacks. To solve this issue, this study proposes a current-fed resonant converter with a wide input range designed for fuel-cell vehicles. The proposed converter adopts a current-fed bridge and an asymmetric active voltage doubler on the primary and secondary sides of the transformer, achieving high step-up capability while minimizing input current ripple. Moreover, it reduces hard-switching turn-on losses compared with conventional symmetric modulations owing to extended asymmetric modulation. Furthermore, the proposed converter features triple-mode operation, enabling various resonant operations to obtain a wide input voltage range and a soft-switching mechanism. As a result, the proposed converter attains high voltage gain, low input current ripple, and high efficiency over a broad input voltage range. Subsequently, a 400-W/380-V prototype is introduced to experimentally affirm the viability of the proposed converter across a specified input voltage range spanning from 40 to 70 V.