A New SEPIC-Flyback DC-DC Converter for Fuel Cell systems

Articles in Press

Document Type : Research Paper

Authors

1 Department of Electrical Engineering, Isf.C., Islamic Azad University, Isfahan, Iran

2 Department of Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran

10.22104/hfe.2025.7747.1372

Abstract

In this paper, a SEPIC converter featuring a novel lossless snubber circuit is proposed for fuel cell applications. In the proposed topology, the main switch turns on under Zero-Current Switching (ZCS) conditions and turns off under Zero-Voltage Switching (ZVS), while all diodes experience Zero-Current turn-off, thereby eliminating reverse recovery issues. Moreover, the energy stored in the snubber circuit is transferred to the output, ensuring that the snubber does not introduce significant power loss to the system. The proposed snubber not only enables soft-switching operation but also enhances the voltage gain of the converter through the use of a three-winding transformer. Additionally, the absence of an auxiliary switch simplifies the control circuitry considerably. The converter has been implemented with a rated power of 200 W, and experimental results confirm the accuracy of both the PSPICE simulations and the theoretical analysis. Low input current ripple, high efficiency of 96.5%, and a switching frequency of 100 kHz make this converter highly suitable for fuel cell energy systems.

Keywords

Main Subjects

Hydrogen, Fuel Cell & Energy Storage

Articles in Press, Accepted Manuscript
Available Online from 13 October 2025

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