A Full Soft-Switching High Step-Up DC/DC Converter With Active Switched Inductor and Three-Winding Coupled Inductor

This article proposes a full soft-switching high step-up dc/dc converter with active switched inductor and three-winding coupled inductor (ASL-TWCI). By utilizing the three-winding coupled inductor (TWCI) with a modified switched capacitor cell, the voltage gain of the ASL-TWCI is further extended without requiring an extreme duty or a high turns ratio of TWCI. Therefore, the voltage stress across the power switches is restricted. By utilizing the leakage energy of TWCI, all semiconductors achieve the zero current switching performance, which has significantly reduced the switching losses of the ASL-TWCI. Additionally, the soft-switching performance is realized by utilizing few components, which reduces the losses and improves the overall efficiency. Moreover, the construction of capacitor-clamped cell has been adjusted to decrease capacitance and voltage rating, which significantly improve the power density of ASL-TWCI. The operating principles, steady-state analysis, design, and extensive performance comparison of ASL-TWCI are described in detail. Finally, a 400 W prototype with 400 V output voltage is fabricated to verify the theoretical analysis.