A Novel Approach to Implement a Single-Stage Step Up/Down Inverter by Using Auxiliary Pumping Circuit

This paper presents a novel single-stage inverter with high step-up ratio and step-up/down capabilities. A forward-pumping circuit is integrated to the 262;uk-derived voltage source inverter (VSI) to achieve a much higher voltage conversion ratio, while avoiding the use of at larger duty ratio of dc-side switch and modulation index of inverter. The proposed inverter can operate oneself naturally to perform capacitive charging in parallel and discharging in series to give a higher voltage multiple, without increasing dc-side voltage stress and sacrificing ac output voltage step-up/down characteristics. Furthermore, one can adopt lower voltage rating devices to further reduce both switching and conduction losses of dc-side switch. The validity of the proposed inverter is be verified by means of some comprehensive results.