Design of a High-Gain Common-Grounded ZVT DC-DC Converter with Sustained Soft Switching

To address the performance requirements of power interface converters in fuel cell vehicles, a high-voltage gain DC–DC converter with a common-ground structure and zero-voltage-transition (ZVT) operation is proposed. The converter employs two interleaved boost cells in an input-parallel output-series (IPOS) configuration to achieve low input-current ripple and high voltage gain. A single auxiliary circuit enables soft-switching for all switches during turn-on and turn-off, while diodes operate under zero-current switching (ZCS), reducing switching and reverse-recovery losses. In addition, voltage stress across devices is limited to half of the output voltage, allowing the use of lower-rated components. A 1 kW prototype operating at 50 V input and 400 V output at 50 kHz is experimentally validated. The converter achieves efficiency above 92.5%, with a peak of 95.46% and up to 97.41% at higher input voltages, while maintaining stable output performance. These results demonstrate the suitability of the proposed converter for high-efficiency fuel cell-based applications.