Design and Experimental Validation of a Fully Soft-Switched High Step-Up DC–DC Converter with Reduced Input Current Ripple for Distributed Generation Systems Applications

This paper introduces a non-isolated high step-up DC–DC converter suitable for distributed generation system applications. The proposed topology uses the zero-voltage-transition (ZVT) technique to achieve soft-switching conditions over a wide range of output power levels, resulting in improved efficiency and reliability. Since the main switch turns on under ZVS conditions, the capacitive turn-on loss is eliminated, thereby reducing switching losses. In addition to the soft-switching capability, the converter provides a continuous input current, which reduces the input filter requirement and improves both power density and cost-effectiveness. Moreover, the converter design effectively increases the voltage gain by utilizing coupled-inductor, switched-capacitor, and voltage-multiplier techniques, allowing the proposed converter to be used in high-voltage applications. The proposed converter employs an independent input inductor and a four-winding coupled inductor implemented using two magnetic cores. Furthermore, the proposed converter features lower voltage stress across the switches, enabling the use of cost-effective, low-resistance MOSFETs, which further improve efficiency. Finally, a common ground structure, the absence of floating switches, and the elimination of the reverse-recovery problem in all diodes are additional valuable advantages of the proposed converter. Comprehensive analytical investigations, together with experimental evaluations conducted at a power level of 200 W, demonstrate that the proposed converter achieves enhanced performance characteristics and outperforms previously reported converter topologies.