Bidirectional Naturally Clamped Soft-switching Current-fed Push-Pull DC/DC Converter

The proposed converter has the following features: 1) zero current commutation (ZCC) and natural voltage clamping (NVC) eliminate the need for active-clamp circuits or passive snubbers required to absorb surge voltage in conventional current-fed topologies; 2) Switching losses are reduced significantly owing to zero-current switching (ZCS) of primary side devices and zero-voltage switching (ZVS) of secondary side devices. Turn-on switching transition loss of primary devices is also negligible. 3) Soft-switching and NVC are inherent and load independent. 4) The voltage across primary side device is independent of duty cycle with varying input voltage and output power and clamped at rather low reflected output voltage enabling the use of low voltage semiconductor devices. These merits make the converter good candidate for interfacing low voltage dc bus with high voltage dc bus for higher current applications. Steady state, analysis, design, simulation and experimental results are presented.