Stability Prediction of Soft Switched Isolated DC-DC Converter

Abstract

Mathematical analysis and stability prediction of soft switched isolated dc-dc converter is presented in this paper. Half bridge dc-dc converter is an attractive topology for low voltage applications due to its simplicity, lower cost, improved reliability and enhanced dynamic performance. Both power semiconductor switches of the proposed isolated converter operate asymmetrically under Zero Voltage Switching (ZVS) to achieve high efficiency and low voltage stress. Furthermore, the ringing resulted from the oscillation between the transformer leakage inductance and the junction capacitance of two switches is eliminated. Conversion efficiency is also improved by providing synchronous rectifier with very small output filter. The operating principle, state space analysis and control strategy of proposed converter is explained with small signal model. Experimental results are presented to explain the zero voltage switching capability and stability features of proposed converter.