Parasitics assisted soft-switching and secondary-clamped current-fed bidirectional voltage doubler for fuel cell vehicles

A novel current-fed secondary-assisted clamped zero current commutated bidirectional full-bridge voltage doubler is proposed for fuel cell vehicles (FCVs). The proposed topology with novel modulation is suitable for interfacing energy storage with fuel cell or dc bus in FCVs. Voltage doubler on secondary side is selected to enhance the gain by 2x and reduce transformer size. 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 eliminating the necessity for traditional active-clamp or passive snubbers. Switching losses are reduced significantly owing to soft-switching of all semiconductor devices. Synchronous rectification may be implemented to obtain high efficiency. Soft-switching and voltage-clamping are inherent and achieved at variation in load and source voltage. Steady state operation, analysis, design, simulation and experimental results are presented in this paper.