K. S. Krikor; Khalid I. Alnaimi; Jamal A. Mohammed
Abstract
The traditional two or three levels inverter does not completely eliminatethe unwanted harmonics in the output waveform. Therefore, using themultilevel inverter as an alternative to ...
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The traditional two or three levels inverter does not completely eliminatethe unwanted harmonics in the output waveform. Therefore, using themultilevel inverter as an alternative to traditional PWM inverters isinvestigated.This paper describes the Optimized Harmonic Elimination Stepped WaveformOHESW technique to improve the output waveform quality of multilevelinverter fed induction motor. A new method is presented where switchingangles are computed such that a desired fundamental sinusoidal voltage isproduced while at the same time certain higher order harmonics are eliminated.The proposed method also is used to minimize the Total Harmonic DistortionTHD of the synthesized multilevel waveform. The THD is investigated over awide range of possible output control voltages and number of voltage levelsused to synthesize the output waveform.Simulation results of a cascade multilevel inverter under OHESW techniquewith 5- up to 15-levels are used to eliminate the (3rd-13th) harmonics.A prototype single-phase cascade 7- level inverter loaded by single-phaseinduction motor is investigated.