Single Phase Seven-Level Inverter topology with Single DC Source and Reduce Device Count for Medium and High Power Applications

This paper present a single phase transformer less seven level inverter topology. The topology is based on the modified H-Bridge inverter. One leg of the H-Bridge inverter is kept same producing two level as usual. The second leg is split into three equal parts with the help of two additional branches to gain access to the additional levels. The added branches comprise of the bidirectional switches. Single DC source is converted into three dc-link using capacitors. A level shifted sinusoidal PWM scheme is used for high frequency control. Performance of the proposed circuit is validated using MATLAB/Simulink software with R as well as RL load. Output voltage and current THD is 15.33% and 2.61% for RL load respectively. Based on the number of dc sources and switches used, the proposed topology is compared with other conventional seven level topologies. The results obtained comply with the norms set for the output voltage and current which makes it suitable for various medium and high voltage applications.