High Step-Up Interleaved Forward-Flyback Boost Converter With Three-Winding Coupled Inductors

A novel high step-up interleaved converter for high-power high-voltage applications is proposed in this paper. Through three-winding coupled inductors, a high step-up conversion with high efficiency is obtained. The proposed converter not only reduces the current stress, but also constrains the input current ripple, which decreases the conduction losses and lengthens the life time of input source. In addition, due to the lossless passive clamp performance, leakage energy is recycled to the output terminal. Hence, large voltage spikes across the main switches are alleviated and the efficiency is improved. Even, the low-voltage stresses on semiconductor components are substantially lower than the output voltage. Finally, the prototype circuit with input voltage 48 V, output voltage 380 V, and output power 2 kW is operated to verify its performance. The highest efficiency is 96.5%, and the full-load efficiency is 92.6%.