A study of symmetrical and various asymmetrical DC source configurations of a novel cascaded multilevel inverter topology

In this paper, a novel structure of cascaded multilevel inverter (MLI) is proposed. Each module of the proposed MLI consists of four numbers of DC sources, seven unidirectional and 2 bi-directional power switches. Each module possesses the capability of generating bipolar voltage level at its output terminals with the help of H-bridge. Hence, the topology is analyzed for both symmetrical and asymmetrical DC source configurations. Extended structure of the proposed MLI topology has been studied where n numbers of basic unit connected cascaded. Two types of asymmetrical DC source configurations have been proposed. As compared with existing MLI topologies, the proposed MLI requires lower components such as switching devices, driver circuits to generate specific number of output voltage level. This further reduces the size and cost of the inverter system. The topology requires less number of conducting switches to generate maximum voltage levels that indicate to lower switching and conduction losses. Extensive simulation studies of 9 levels symmetrical and 13 levels asymmetrical proposed MLI have been done in Simulink /MATLAB. The different results of simulation studies prove the effectiveness of the proposed topology.