A New Zero Voltage Transition Non-Isolated Bidirectional DC-DC Converter

Abstract

The primary objective of this study is to examine and develop novel Zero Voltage Transition (ZVT) non-isolated bidirectional DC-DC converters specifically designed for battery storage purposes in hybrid electric vehicles. The initial focus is on a bidirectional converter (BDC) that has been specifically engineered to possess a high voltage gain. Additionally, this converter is equipped with the capability of performing soft-switching operations on Insulated Gate Bipolar Transistors (IGBTs). To attain minimized switching losses and enhanced efficiency, the primary insulated-gate bipolar transistors (IGBTs) are operated under zero-current conditions during the commutation phase from turn-on to turn-off state. The zero-current turn-off operation is achieved through the utilization of a soft-switched cell, comprising of a resonant inductor, capacitor, and supplementary IGBTs. A novel converter is suggested, which incorporates zero-voltage transition operation for the insulated-gate bipolar transistors (IGBTs). The performance of the hard-switched bridgeless dc-dc converter (BDC) has been enhanced with the incorporation of supplementary soft-switched cells. The soft-switched cell is composed of resonant inductors, capacitors, and auxiliary switching devices. The soft-switched cell has been utilized to achieve zero voltage turn-on of the primary insulated-gate bipolar transistors (IGBTs). The operation of this converter involves charging the battery in the buck mode and utilizing the charged battery to give the desired output voltage in boost mode.  This study involved doing a design simulation analysis on a high-gain bidirectional converter (BDC) within a 70V/300V power system. The converter was evaluated under an operating frequency of 50kHz, with a maximum output power of 800W. The high-gain soft-switched BDC demonstrated an efficiency of 96.5% in boost mode and 97% in buck mode. This study presents the operational principles, design analysis, and simulation assessments.