A Novel Integrated Single-Phase Inverter With Auxiliary Step-Up Circuit for Low-Voltage Alternative Energy Source Applications

This paper presents a novel integrated single-phase inverter with both high step-up ratio and buck-boost capabilities for low-voltage alternative energy source applications. An auxiliary step-up circuit is integrated with an isolated Ćuk-derived voltage-source inverter to achieve a much higher voltage-conversion ratio while avoiding using extreme duty ratios in both dc-side and ac-side switches. In addition, the proposed circuit possesses the automatic energy-transfer characteristic between parallel charging and series discharging of two capacitors to achieve a much higher voltage level. Moreover, the voltage stress of dc-side active switches can be reduced to below one half as compared with that of a traditional isolated Ćuk converter. Finally, steady-state characteristics, performance analyses, and representative experimental results are also made to show the merits of the proposed inverter.