Analysis and design of an active-clamping ZVS isolated inverse-SEPIC converter

This paper proposes an active-clamping zero-voltage-switching (ZVS) isolated inverse-SEPIC converter. The high voltage spikes when turning off the switches are eliminated. The energies stored in the parasitic elements can be recycled to achieve the ZVS of switches. Therefore the converter efficiency increases substantially, and the circuit cost is also reduced. Detailed analysis and design of this new topology are described. Experimental results are recorded for a prototype converter with a DC input voltage ranging from 130 to 180 V, an output voltage of 12 V and an output rated power of 120 W, operating at a switching frequency of 65 kHz. The average active-mode efficiency is above 88 %.