Fully Soft Switched Resonant Isolated SEPIC Converter With Wide Input Voltage Range

In this article, an isolated half-bridge series resonant converter (HB-SRC) based on the single-ended primary-inductor converter (SEPIC) topology (HB-SSRC) with a wide input voltage range is proposed. In this topology, the transformer leakage inductance is effectively used and the zero-voltage switching (ZVS) operation is provided for all the semiconductor elements. A simple fixed frequency asymmetrical pulse width modulation (APWM) scheme is used in the proposed converter to regulate the dc output voltage. The series resonant network is designed at the resonant frequency for ensuring the load-independent voltage gain of HB-SSRC. Detailed theoretical analysis of the proposed converter is presented. A 100-W prototype with 24-V output voltage at 200-kHz switching frequency is designed and implemented for a wide input voltage range of 80–240 VDC to verify the converter analysis and performance.