Impact of Duty Ratio and Saturation Cycling on Efficiency in Current-Fed Push-Pull DC/DC Converter with Active-Clamp

Abstract

This paper investigates the efficiency performance of a current-fed push-pull DC/DC converter incorporating an active-clamp circuit. The primary focus is to optimize the converter's efficiency by considering the influence of duty ratio and saturation cycling in the boost inductor. The study presents a new efficiency analysis model by incorporating theoretical, simulation, and experimental approaches. Through detailed analysis, the relationship between duty ratio, voltage gain, and efficiency is explored, with an emphasis on achieving high efficiency while minimizing input current ripple. This paper defines “saturation cycling” as a phenomenon that inherently arises when the boost inductor alternates between saturated and unsaturated states. This behavior is an unavoidable physical consequence of the design aimed at minimizing input current ripple. The results indicate that it is impossible to simultaneously achieve zero input ripple and maximum efficiency, thus necessitating careful duty ratio selection. Experimental validation confirms that the converter can reach efficiencies of up to 96.565%, demonstrating the robustness and performance of the proposed design. The findings suggest optimal design practices for high-efficiency power conversion in fuel cell applications and similar high-current energy conversion systems.