DESIGN OF A MULTI-PULSE CONVERTER FOR FIELD ORIENTED CONTROL OF INDUCTION MOTOR FOR HARMONIC REDUCTION

Abstract

It is well known that undesirable harmonic currents may be generated in a field control of induction motors because of the switching components used in the rectification and inversion proces. The rectification of AC power to DC power itself may in general produce undesirable current harmonics. These non-linear components cause severe current harmonics that may not be tolerated by either a shutdown of the device or unacceptable powering of the devices. The great majority of power electronic equipment operates from an ac source but with an intermediate dc link. Thus, a significant opportunity exists to facilitate power electronics applications by using ac to dc rectifiers that produce low harmonic current in the ac source. Multi-pulse converters in general and non-isolated multi-pulse converters in particular can be applied to achieve clean power which is of major interest in higher power ratings. In general, by increasing the number of pulses in multi-pulse converters THD (total harmonic distortion) can be reduced and other associated performance parameters can be enhanced. The twelve pulse and a twenty four pulse multi- pulse converter is being designed in this work. The total harmonic distortion is being compared with a conventional six pulse type of multi level converter. The model is being simulated in a MATLAB simulink environment and results are being discussed.