Comparison of conventional and new cascaded multilevel inverter topologies based on novel indices

This paper proposes new indices of cascaded multilevel inverters (MLIs) in order to compare the conventional topology with 10-existed new topologies. Reduction in the number of power switches is the main target of these new topologies. This aim is to reduce the total cost of designed inverters, though the mentioned aim is not enough to design new inverters. Thus, in this study, four comparative indices including sources power uniform distribution index (SPUDI), switches current uniform distribution index (SCUDI), switches loss uniform distribution index (SLUDI), and switches voltage uniform distribution index (SVUDI), are proposed. In addition, it is shown that in most of the new topologies, reducing the number of switches can lead to lowered values of the proposed indices, after which non-uniform power, current, loss, and voltage pattern are obtained. The results prove that mere emphasis on the number of switches, along with the exclusion of either of the proposed indices will cause significant problems, where cost reduction may be underachieved. Based on new indices, the advantages of conventional topology over new ones are presented in this study.