Muhammad Hammad ZafarSadam SarwarAyaz Ahmad Butt2015-05-222015-05-222015https://escholar.umt.edu.pk/handle/123456789/1554Variable Frequency drive is a drive use to controls the speed of motor. It uses the technique of PWM (pulse width modulation) to control the frequency of a sinusoidal voltage produced by PWM inverter. Frequency drives widely used to control the speed of pumps, conveyer belts, blowers and in centrifuge applications. It plays an important role in industrial applications .VFD is sub divided in to three main parts, RECTIFIERS which converts AC voltage to DC voltage by using bridge circuit, DC link or a link to the DC circuit and INVERTER.BS ThesisFrequency DriveThesis