A Novel Quadratic High Step-Up Converter Featuring Low Ripple Input Current and Lossless Snubber

This paper introduces a high step-up DC–DC converter that combines a quadratic boost architecture with a flyback stage and incorporates a novel lossless snubber network to enhance efficiency and voltage stress performance. The converter achieves a substantial step-up ratio increase with diminished switch over-voltage, while maintaining soft-switching operation for all semiconductor devices. Consequently, transition-related losses are suppressed and diode reverse-recovery is mitigated. The leakage inductance energy is efficiently captured by the snubber and redirected to the output, contributing to overall performance enhancement. The circuit design is simplified due to the ground-referenced single power switch, which facilitates easier control and gate driving. Moreover, the low input-current ripple renders the converter configuration highly suitable for photovoltaic energy systems. A comprehensive theoretical analysis is conducted, and a 140 W prototype has been built. The experimental results validate the proposed analysis and indicate a 4% efficiency improvement over conventional hard-switched equivalents.