A new soft switching interleaved flyback converter with recovery leakage inductance energy

In this paper, a ZVS interleaved flyback converter with two transformers is presented, which consists of two active clamp flyback converters and the main switch of one converter acts as an auxiliary switch of another converter. This converter has less auxiliary elements and less voltage and current stress compared to similar soft switching interleaved flyback converters. The introduction of a new auxiliary circuit for soft switching, in addition to increasing efficiency, minimizes the number of added semiconductors. Also, another advantage of this structure is the applicability of the provided auxiliary circuit to other isolated converters. The soft switching conditions in this converter are created by the auxiliary circuit in such a way that the converter switches turn on and off under ZVS conditions and the converter diodes turn on and off under ZCS conditions. The efficiency of the proposed ZVS interleaved flyback converter at full load is increased by 5%. Another advantage of the proposed converter is that the Q2 switch, in addition to providing zero voltage switching conditions for the Q1 switch, it also transmits energy and increases the density of the converter power and reduces the current stress. The converter is thoroughly analyzed and a 300W laboratory prototype is made to confirm its correct operation and practical results are presented.