A novel ZCZVT forward converter with synchronous rectification

Abstract

A novel zero-current-zero-voltage transition (ZCZVT) forward converter with synchronous rectification (SR) is presented in this paper. The proposed converter is operating at 300 kHz and processes the features of both zero-voltage transition (ZVT) at turn on and zero-current transition (ZCT) at turn off for the main switch. The auxiliary switch also achieves zero-current switching (ZCS). The flux of transformer can be reset without tertiary winding. The steady-state analysis and design considerations are investigated in detail in this work. Moreover, a self-driven synchronous rectification is also added to the ZCZVT forward converter to reduce the conduction losses of the output rectifier. For 48-V input and 12-V 100-W output, a prototype of the proposed converter for 300-kHz switching is built to verify the theoretical analysis. Finally, the power losses are well estimated. The overall efficiency of the proposed converter is achieved at 89% at full load.