A Family of True Zero Voltage Zero Current Switching (ZVZCS) Nonisolated Bidirectional DC-DC Converter With Wide Soft Switching Range

This paper proposes a true zero voltage zero current switching (ZVZCS) nonisolated bidirectional dc-dc converter with reduced component count. An auxiliary resonant network-which comprises of an inductor, capacitor, diode, and two switches-provides the zero voltage switching 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 zero current switching 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.