Soft-Switching Ultra-High Step-Up DC-DC Converter Featuring Coupled Inductor and Low Voltage Stress on Switches

This paper introduces a non-isolated DC-DC converter for achieving ultra-high step-up (UHSU) voltage conversion with the use of a two-winding coupled inductor (CI). In this proposed UHSU converter, a significant increase in voltage is achieved by employing low duty cycles and a reduced turn ratio for the CI, which results in a smaller CI core size. Additionally, the presented UHSU converter features soft-switching capabilities for both power switches and diodes, contributing to high efficiency. This design keeps the voltage stress on the switches low, thereby minimizing losses and enhancing overall efficiency. Detailed analysis of the operational modes is provided, along with a comparison to other topologies to showcase the effectiveness of the suggested UHSU converter. Finally, the performance of the proposed UHSU circuit is verified through the construction and testing of a 150-W laboratory prototype operating at a switching frequency of 50kHz with Vin=20V and Vout=300V.