A novel non isolated DC-DC step up converter for photovoltaic systems

High voltage gain dc-dc step up converters are crucial in photovoltaic systems generating electric power from solar energy. This paper presents a novel non isolated step up dc-dc converter which provides very large voltage conversion at a small duty cycle (duty cycle < 0.5). Due to the low duty cycle, the reverse recovery problem, conduction loss at the switches and electromagnetic interference are reduced. The power electronic switches in the proposed converter operate simultaneously depending on a single control signal. Firstly, the analysis at steady-state has been performed in continuous mode of operation. This gives the mathematical expressions for average output voltage, voltage gain, voltage strain across the switches and diodes, and peak to peak ripple current of inductor and ripple voltage of output. Secondly, a detailed operation has been carried out in discontinuous conduction mode and in boundary between continuous and discontinuous modes of operation. This analysis provides the mathematical expressions for inductor time constant to estimate the size of the inductor. Thirdly, a comparative analysis is shown to compare the proposed converter with the conventional step up converter. Finally, simulation results verify the complete analysis.