Integrated boost-sepic converter for high step-up applications

A general boost converter has limited voltage step-up ratio because of its parasitic resistances. Thus, it is not applicable for high step-up applications. As a solution, combining a boost converter with a series output module can be considered to supplement the insufficient step-up ratio. By applying this concept, a new integrated boost-sepic (IBS) converter, which provides additional step-up ratio with the help of an isolated sepic converter, is proposed in this paper. Since the boost converter and the sepic converter share a boost inductor and a switch, its structure is simple. Moreover, the proposed IBS converter needs no current- snubber for the diodes, since the transformer leakage inductor alleviates the reverse recovery. The operational principle and characteristics of proposed converter are presented, and verified experimentally with a 200-W, 42-V_dc input, 400-V_dc output converter prototype.