Parasitics-Assisted Soft-Switching and Secondary Modulated Snubberless Clamping Current-Fed Bidirectional Voltage Doubler for Fuel Cell Vehicles

A current-fed full-bridge bidirectional voltage doubler with secondary-assisted device voltage clamping and zero-current commutation (ZCC) is proposed for fuel cell vehicles (FCVs). The proposed topology is suitable for interfacing energy storage and/or fuel cell stack with a dc bus in FCVs. A voltage doubler on the secondary side is selected to enhance the gain by 2×, reduce transformer size, and efficiently reduce the low-frequency dc current harmonics. Parasitics-based zero-voltage switching (ZVS), secondary-based zero-current switching of low-voltage-side devices, and ZVS of secondary devices are achieved. The proposed secondary modulation technique naturally clamps the voltage across the primary-side devices with ZCC, thus eliminating the necessity for traditional active-clamp or passive snubbers. Switching losses are reduced, owing to the soft-switching of all semiconductor devices. Steady-state analysis and design are studied and explained. The experimental results of a 1-kW proof-of-concept hardware prototype are shown to demonstrate the performance and confirm the proposed claims.