Performance Analysis of Harmonic Elimination Techniques in Voltage Controlled Converters

Abstract

This paper presents a comparative analysis of various techniques used for elimination of the selected low-order harmonics in an inverter-output voltage waveform. The techniques employed are advanced switching patterns to result a voltage waveform with minimum harmonic contents, fixed frequency and constant voltage magnitude. Newton Raphson Algorithm is used to compute the appropriate switching angles, where the total harmonic distortion (THD) is the cost function to be minimized. Single phase inverter is simulated using Sim Power System Matlab Toolbox with switching angle computed to minimize THD. Models of inverters and resulting THD and output voltage spectrum are presented in this paper. Among Diode Clamped Multilevel inverter (DCMLI), Pulse Width Modulation (PWM) and combination of both. The later results minimum THD with less number of controlled switches compared to DCMLI.