Nonisolated High-Step-Down DC–DC Converters With Low Component Count and Voltage Stress

Abstract

This paper proposes two new non-isolated high step-down DC/DC converters. The converters' voltage conversion ratio and their semiconductor components' voltage stress are improved compared to the conventional buck converter. By coupling the inductors of the first proposed converter, its volume and price is reduced. By employing a clamp circuit with low elements to the first proposed converter, the second proposed converter is introduced, in which its voltage conversion ratio and the voltage stress of components are improved significantly; thus, in high input voltage applications, high-quality components (switches with low on-resistance and diodes with low forward voltage) can be used. In these converters, the leakage inductances of the coupled inductor are clamping, and their energy is recovered. The proposed converters have fewer elements than related high step-down counterparts' converters leading to lower volume and losses due to lower elements, increasing efficiency. The switches of the proposed converters are switches simultaneously, reducing the converters' control circuit complexity. This paper discusses the theoretical analysis and operational principle of both proposed converters. Besides, to verify their performances, experimental results of the converters with 155-24 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> input and output voltage are presented.