Harmonic Analysis of Symmetrical and Asymmetrical Cascaded H-Bridge Multilevel Inverter

Abstract

This paper proposes harmonic comparison between Symmetrical and Asymmetrical CHB MLI using multiple carrier based phase disposition PWM technique (PDPWM). Topologies of different multilevel inverter are reported in the literature, but mainly this work focuses on the harmonic comparison of Symmetrical and Asymmetrical cascaded MLI with same count of sources and switches. In this paper, PWM switching technique for harmonic comparison of both symmetrical and asymmetrical cascaded MLI is PD. Total harmonic distortion is analyzed in FFT window. Results are observed in SIMULINK/MATLAB software. In these comparative results we can see that an asymmetrical configuration is producing higher voltage levels in voltage output with equal quantity of component compared with the 5-level symmetric inverter and this could lead towards the reduction in harmonic content of output voltage. The benefits of this method of control are applicability and simplicity for n-levels MLI, with no any considerable change in the control circuitry. The experimental measurement results validate proper operation of the discussed MLI