Effect of parasitic components in the integrated boost-flyback high step-up converter

The increasing interest for renewable energy sources like those based on photovoltaic panels and fuel-cells have driven the power electronics community toward the study and development of high step-up DC-DC converters, able to efficiently interface the low voltage side of such energy sources with the high-voltage dc link side of the grid connected inverter. Between the different investigated topologies, those based on the combination of a boost section and a flyback one are quite interesting, thanks to the possibility to boost the output voltage while keeping the switch voltage stress at a reasonable level. However, the analysis reported in literature always neglect the effect of parasitic components that strongly modify the converter behavior. In this paper, the analysis of the integrated boost-flyback converter with voltage multiplier is presented that includes the effect of the parasitic components. It is shown that a resonance occurs that helps to increase the converter´s voltage gain. Experimental results taken from a 300 W rated prototype are included, showing a good agreement with the theoretical expectations.