Modified design TWCI-based high step-up DC-DC converter with reduced elements and low input current ripple for renewable applications

This paper presents a non-isolated high step-up DC-DC converter based on a modified three-winding coupled inductor, which is proposed for renewable energy applications. The proposed converter, which embeds a modified voltage multiplier cell utilizing a secondary winding of a coupled inductor, achieves an ultra-high voltage gain without requiring extreme duty cycles. and not only minimizes the overall component count but also significantly reduces voltage stress across semiconductors and capacitors, thereby lowering system cost. Moreover, the employed cell based on the coupled inductor offers simplicity and flexibility, making it suitable for integration into other converter topologies as well. The architecture further ensures a continuous, low-ripple input current and maintains a common-ground connection between source and load, making it highly compatible with photovoltaic and fuel-cell integration. Comprehensive analysis of the operating principles, steady-state performance, and device stresses is provided, together with theoretical efficiency estimation and comparative evaluation against recent state-of-the-art designs. Experimental validation is conducted using a 250 W prototype converting 24 V to 400 V, achieving a peak efficiency of 95.3%, which substantiates the analytical predictions and highlights the practical effectiveness of the proposed topology for next-generation renewable energy systems.