Application of Cycle Skipping Modulation in Buck–Boost Photovoltaic Microconverters

Cycle skipping modulation (CSM) was previously demonstrated for efficiency improvement in different converters intended for photovoltaic module-level applications. Currently, galvanically isolated buck–boost converters (IBBCs) have attracted increased attention in these applications due to the uptake of dc microgrids. This article revisits the topic of CSM and applies it to a quasi-Z-source-based IBBC. Two new CSM schemes are proposed for the given converter. Power losses in components are estimated for different CSM schemes to predict efficiency improvement that could be attained. A 300-W prototype was built to verify the efficiency estimation results. The efficiency trends are the same between the theoretical estimations and experimental measurements. Converter operation was studied for two bell-shaped solar irradiance daily profiles using a solar array simulator. The converter demonstrates efficiency improvement during morning and evening hours for a sunny day and during the whole day for overcast sky conditions.