A High Step-up DC-DC Converter with Three-winding Coupled Inductor for Sustainable Energy Systems

This paper proposes a high step-up dc-dc converter with a continuous input current which is suitable for sustainable energy systems. A three-winding coupled inductor, two power switches, three diodes, and three capacitors are utilized to perform the functions of active switched inductor and switched capacitor. By charging the two primary windings in parallel, and discharging the two primary windings in series to the intermediate capacitor and the output, the conversion ratio can be further improved with lower voltage stresses and current stresses on its power switches. In addition, the energy stored in the leakage inductance is recycled to reduce the voltage spikes of the power switches. Eventually, a laboratory prototype with an input voltage of 36 V - 48 V, and output voltage of 400 V - 600 V with a rated power of 600 W is implemented to validate the correctness and effectiveness of the theoretical analyses. The maximum efficiency and full load efficiency are 97 % and 96.2 %, respectively.