JEE_V2_N3_RP2 E. Chandra Sekaran P. Anbalagan S. Elango Journal on Electrical Engineering 2230 – 7176 2 3 26 35 harmonics, THD, diode clamped multi level inverter The usage of non-linear loads like variable speed drives, SMPS, UPS, etc., connected to power systems cause the harmonic currents which make sinusoidal currents/voltages to non-sinusoidal currents/voltages. Harmonic voltage results from the harmonic currents interacting with the impedance of the power systems, which results in the power quality problem. In this research paper, the harmonic levels of a sinusoidal pulse width modulated two level three-phase inverter are compared with the sinusoidal pulse width modulated three level inverter. The three-phase three level diode clamp inverter is designed and simulated using PSpice and the DSP based hardware model is developed using IGBT as the power devices. The hardware model is tested for resistive load, which results are obtained with the help of Fluke 434 power quality analyzer. In this multilevel inverter the magnitude of the fundamental component is increased and the total harmonic distortion decreased by 50% for both practical and simulated cases, when compared to the three phase two level conventional PWM inverter. January - March 2009 Copyright © 2009 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=255