A Review of Some Recently Proposed Topologies for Multilevel DC-AC Conversion

Multilevel inverter (MLI) is gaining rapid popularity in high/medium power applications due to low THD and high quality output waveform. Recently, the MLI topologies with reduced part count has attracted the researchers by offering higher number of output voltage level with reduced part count as compared to classical topologies (CHB, NPC and FC). It is observed that these recently proposed topologies are aimed to increase the output level with less number of components but the discussion over their suitability for a particular application is not yet explored completely. The main purpose of this paper is to provide an instructive review and analysis of existing MLIs with reduced part count. An exhaustive comparison of MLIs are assessed based on the number of switches, standing/blocking voltage across the switches, conduction losses, switching losses and cost. With the outcome of comparison results, suitable structure of MLI can be judged with reduced number of components and losses for given applications.