A New Three-Winding Coupled Inductor High Step-Up DCDC Converter Integrating With Switched-Capacitor Technique

In this article, a modified quasi-Z-source high step-up dc-dc converter is suggested for renewable energy applications, which features lower voltage stress of switch and wider region of duty cycle control. In addition, the superiority of the novel converter embodies ultrahigh voltage gain with a small turns ratio of coupled inductor, continuous input current, and an adjustable wide range of voltage gain. From coupled inductor, a step-down type winding (turn ratio less than 1) and a step-up type winding (turn ratio more than 1) not only enhance the voltage gain, but also provide more flexible voltage regulation. The low pulsating input current can decrease the volume and capacity of the input filter. Moreover, the switched-capacitor contains an internal passive clamp circuit for the power switch, which can alleviate the voltage spike during turn-OFF operation and restore the leakage inductor energy. The operating principle and theoretical analysis of the converter are given in detail. A 200-W prototype was fabricated in the laboratory according to the design guideline, and the experimental results verify the validity of analysis.