Symmetrical And Asymmetrical Topology of Cascaded Multilevel Inverter With Reduced Number of Switches And DC Sources

Abstract

Cascaded H-bridge Multilevel Inverter(MLI) is the most popular MLI amongst the ‘classical’ topologies, partly owed to its modularity and partly for having fewer amount of switches than the other two for the same output generated. It is quite simple in construction. Simplicity and modularity makes it easier to manufacture and packaging too. The Cascaded H- bridge Multilevel Inverter is composed of an H-bridge cell and an autonomous DC source. The DC source could be capacitors, batteries or even photovoltaic cells, making it attractive for renewable energy systems. It generates a good sinusoidal output waveform with little total harmonic distortion (THD). A major disadvantage of Cascaded Multilevel inverter is, it requires multiple DC sources. This paper proposed a novel topology for symmetrical and asymmetrical multilevel inverter having less number of power electronic switches, which helps in reducing the cost and area of installation and reduce the complexity of the control system. This paper is subdivided into introduction explaining in short about the structural components of the inverter then after that analysis of the proposed inverter that is switching strategy and operational principles are given. This paper represents Symmetric Cascaded Multilevel inverter which utilizes variable frequency carrier predicated pulse width modulation techniques. This topology helps in decreasing total harmonic distortion and helps to reduce the switching losses for various level inverters. The simulation study about the performance and operation of the suggested topology has been performed in MATLAB/SIMULINK. The objective of this paper is to implement less number of switches and DC power source to achieve a different level of MLI as compared to the traditional converter topologies.