Three switch high step-down converter

Abstract

A step down converter is presented here which is having only one coupled inductor and one energy transferring capacitor. The step down converter is having much lower voltage conversion ratio so the duty ratio needed is only small. The voltage conversion ratio is linear, thereby making control quiet easy. The merits of the converter are if one switch fails or is abnormally controlled a high voltage does not appear on the output terminal thus the output load can be protected and another merit is that the converter contain only three switches. In the step down mode the capacitor is connected between the input voltage and coupled inductor, which plays a certain role to step down the input voltage. The structure of the converter is quiet simple and very suitable for industrial applications. The converter is having high efficiency and switching losses can be greatly reduced. In this study, the operating principles and experimental results are provided to verify the effectiveness and performance of the converter. Moreover, in the modes of operation, the switches Q1, Q3 and Q4 can achieve ZVS turn-on. To verify the effectiveness of the converter, a simulation is done on MATLAB/Simulink.