Multilevel Inverters: A Review of Recent Topologies and New Modulation Techniques

The advent of high power and medium power appliances has given substantial importance to Multilevel Inverters (MLI) in recent times. The MLI is widely used in driving AC loads which requires to be operated with low harmonics. In this paper, the various MLI topologies and the modulation techniques implemented on MLIs are reviewed. While reviewing the various MLI topologies, they are categorized into symmetrical type and asymmetrical type. All the existing MLIs topologies and those that are developed in future can be categorized into one of these two categories. A comprehensive review is done of these topologies to examine the various performance parameters. The modulation techniques are also classified into fundamental switching frequency (FSF) modulation techniques and high switching frequency (HSF) modulation techniques. This classification provides an easy understanding of the concepts that are conveyed by MLI. This paper also gives a broad understanding of the various features of each modulation technique.