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

This article proposes two new nonisolated high-step-down dc–dc converters. The voltage conversion ratio of converters and the voltage stress of their semiconductor components are improved compared with 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 those of related high-step-down counterparts leading to lower volume and losses due to lower elements, increasing efficiency. The switches of the proposed converters switch simultaneously, reducing the converters' control circuit complexity. This article discusses the theoretical analysis and operational principle of both the proposed converters. Besides, to verify their performance, experimental results of the converters with 155-to-24-V input and output voltage are presented.