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

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