Design and Performance Analysis of Buck–Boost, SEPIC, and Modified SEPIC DC–DC Converters for Fuel Cell-Based Applications

Abstract

This paper presents the design and performance comparison of three non-isolated DC–DC converter topologies—Buck–Boost, SEPIC, and Modified SEPIC converters for fuel cell-based applications. Fuel cells produce a variable DC output that requires effective power conditioning to maintain a stable supply. The Buck–Boost converter provides both step-up and step-down capability but produces an inverted output with higher ripple. The SEPIC converter eliminates polarity inversion and ensures continuous input current, although at the cost of increased circuit complexity. To overcome these limitations, a Modified SEPIC converter with enhanced voltage gain, reduced ripple, and improved efficiency is proposed. Simulation studies are conducted under identical operating conditions to evaluate key performance parameters. Loss analysis, load variation studies, and hardware implementation are carried out to validate converter performance. The results demonstrate improved voltage regulation, stable operation, and an efficiency of approximately 92%, exhibiting performance comparable to recently reported high-gain converter topologies. Hence, the Modified SEPIC converter is a suitable choice for fuel cell-based power conversion systems.