A High Step-Up Nonisolated DC–DC Converter With Flexible Voltage Gain

In this article, a high step-up nonisolated dc–dc converter is proposed to provide high voltage gain with low voltage stress on semiconductors. The main feature of the proposed structure is its flexibility in providing constant output voltages with a reasonable range of voltage stress. This flexibility of the voltage gain is achieved by different combinations of duty cycles. Also, this feature improves the efficiency of the proposed converter. The structure consists of three switches, two inductors, three capacitors, and four diodes. In this article, descriptions of continuous conduction mode, discontinuous conduction mode, boundary condition mode, nonideal model, and control method are presented. Comparisons between the proposed converter and other related structures show that in this converter, the voltage gain is improved and semiconductors voltage stresses are reduced. In order to verify the mathematical analysis, a 500-W laboratory prototype of the proposed converter is built and its experimental results are investigated completely.