An improved active-clamp ZVS forward converter circuit

In order to achieve zero voltage switching (ZVS) easier for both primary switch and auxiliary switch in the active clamp forward converter, an improved active-clamp ZVS forward converter topology is proposed in this paper. Compared with the conventional active-clamp forward converter, the improved one with an auxiliary network which is consisted of a clamp capacitor and an inductor could easily achieve ZVS in full-load range. Therefore the circuit efficiency is increased by reducing the switching loss of the switches. The operation principles of the proposed converter circuit are analyzed in detail and the performance is compared with the conventional one. The design procedure and the experimental results are presented for a converter with a 230 V input; 14.4 V/10 A output. The experimental results match the theoretical analysis very well.