A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1998

In the present, harmonic distortions from the use of adjustable speed drives have a significant impact on other system components and equipment operating within a facility and even at other facilities on the utility distribution system. The increasing use of static thyristor rectifiers has resulted in some unwanted side effects, one of that is the level of harmonic voltage distortion imposed on the supply network. The current drawn from the supply network by a thyristor rectifier is largely non-sinusoidal and contains various harmonic currents in addition to the fundamental 50/60 Hz component. The harmonic currents present and their respective amplitudes depend largely on the bridge configuration and, therefore, the number of de current pulses per supply cycle. Thus the use of thyristor drives system in an industry involving control of the voltage and speed of induction motor. The result of these harmonic currents flowing in the supply network is to generate harmonic voltages across the various supply impedance. This paper is presents with analytical and experimental investigations on harmonics in the voltage and current waveforms of an induction motor fed from Adjustable Speed Drive. A computer calculates is used to evaluate the harmonic spectrum of a given waveform, which is obtained from the mathematical model of a drive, which controls by PWM inverter in the stator phases of a delta-connected induction motor. In addition, tests and measurements of torque-speed, voltage, current, harmonics components, and all electrical power from direct an actual system in laboratory. And then analysis of resulting experiments by separate as two parts. The first is measurement data from input of ASp. Second is measurement data from out put of ASD or input of an induction motors. And results compared to an analysis solution. In final of this paper, analysis model of Induction Motor circuit by uses a computer calculates of each harmonic distortion with non-sinusoidal voltage supply. The finally, include the simply economics of ASD relate to induction motor.