Performance Study of a Modified Sine Wave Inverter


This paper presents the performance of a modified sine wave voltage sourceinverter with duty cycle. Evaluation of quality factors like the Total HarmonicDistortion THD of the output voltage for various values of switching-on angle αindicates that the minimum harmonic distortion occurs at α=23.2180, where theTHD is 28.96%, about 60% of that of the square wave. The 3rd harmonic is about12.61% of the fundamental, and about third of the square wave.The current paper, illustrates the inverter waveforms and how different typesof loads behave when operating from them. Therefore, the THD of the outputcurrent depends on the load types. Results of typical load types are presented.No heavy filters or complex timing circuits are necessary; therefore, theresulting inverter is smaller, lighter weight, and simpler, implying greaterreliability and lower cost. These advantages invite a closer look at inverter-motorsystems. Variations in induction motor performance may occur when the motor isdriven from a modified sine wave inverter rather than a sine wave source.