A Family of True Zero Voltage Zero Current Switching (ZVZCS) Non-isolated  Bidirectional DC-DC Converter with Wide Soft Switching Range        

Abstract

This paper proposes a true zero voltage zero   current switching (ZVZCS) non-isolated bidirectional dc-dc  converter with reduced component count. An auxiliary  resonant network—which comprises of an inductor,  capacitor, diode and two switches provide the ZVS  transitions of the main switches at turn on and turn off  instants. In addition, a pair of auxiliary inductors, which  act as inductive snubbers, aids the ZCS transitions. The  proposed configuration is able to provide soft  commutation for the main switches for a wide range of  input voltage, switching frequency and load current  variations—thus significantly improving the efficiency  profile over a wide operating window. Besides, the  auxiliary switches are also soft commutated, while the  reverse recovery loss induced by the high side diode is  eliminated. The ZVZCS soft switching operation is  demonstrated by a 150 W prototype converter; it is proven  consistent with the waveforms derived from the  theoretical analysis. Its performance is evaluated against  the standard hard-switched boost, buck and several other  leading soft switching converters published in the recent  literature. The maximum full load efficiency at 100 kHz is  recorded at 98.2 % and 97.5 % in the boost and buck  modes, respectively.