Soft-Switched Asymmetric Interleaved WCCI High Step-Down Converter With Low-Voltage Stress

In this article, an asymmetric interleaved nonisolated high step-down dc–dc converter is proposed, which is developed by synthesizing buck and Cuk converters. The main advantages of this topology are low main switches voltage stress, extended duty cycle, continuous output current with low ripple, and providing soft-switching conditions for the main switches and diodes. The switches are turned on under zero-voltage switching (ZVS) condition and capacitive turn-on losses are removed. Besides, the diodes turn-on and off under zero-current switching (ZCS) condition and reverse recovery losses are eliminated. The series capacitors and coupled inductors techniques are used to improve conversion ratio and extend duty cycle without imposing extra voltage stress across the active switches. In addition, winding-cross-coupled inductors (WCCI) technique is used to improve the output current ripple. A 200-W laboratory prototype with 310-V input voltage and 24-V output voltage is implemented to confirm the converter operation and theoretical analysis.