Applying a Novel CLDD Lossless Snubber for SEPIC Converters

This paper proposes a CLDD lossless snubber for application in SEPIC converters. Unlike conventional designs, this snubber employs no active components, utilizing instead two diodes, a snubber inductor, and a snubber capacitor to reduce switching losses and enhance efficiency. The paper thoroughly explains its operating principle, derives detailed mathematical expressions related to the components for better understanding its mechanism, and calculates the voltage and current stresses on the switching components. During the design of this lossless snubber, particular attention is paid to component selection to ensure stable converter operation. This lossless snubber effectively enhances the conversion efficiency of the circuit topology. Finally, a 60 W prototype DC-DC SEPIC converter with 30 V output was designed and tested to evaluate the proposed circuit. Experimental validation demonstrates that the proposed topology boosts peak efficiency from 85.63% to 93.72% (8.10% improvement) across the entire load range, confirming its structural simplicity and effectiveness.