High voltage gain single-switch non-isolated DC-DC converters for renewable energy applications

A new class of single-switch non-isolated dc-dc converters with high-voltage gain and reduced semiconductor voltage stress is proposed in this paper. The proposed topologies utilize a voltage multiplier cell and/or hybrid switched-capacitor technique for providing high voltage gain without extreme switch duty-cycle. This enables the use of a lower voltage and R_DS-ON MOSFET switch, which will reduce costs as well as switching and conduction losses. The components´ voltage ratings and energy volumes of passive components of the proposed converters are greatly reduced compared to other high step-up converters. In addition, the low voltage stress across the diodes allows the use of Schottky rectifiers for alleviating the reverse-recovery current problem, leading to a further reduction in the switching and conduction losses. Other advantages of the proposed topologies include: continuous input/output current, simple structure and control. The principle of operation, theoretical analysis, and performance comparisons between the proposed and other high step-up converters is performed. Experimental results of a 50 W / 240 V_dc with 24 V_dc input voltage are provided to evaluate the performance of the proposed scheme.