A review & analysis of harmonics in Variable Frequency Drives (VFDs)

In this manuscript, the author has tried to analyze a study of Variable Frequency Drives. Variable frequency drives are energy saving drives. But they generate harmonics generates. Harmonics introduced by any means affect the performance parameters of any system The presence of harmonics is the system for a long duration & that, too, of higher order affect the various parameters in a Power distribution system. Harmonics change the shapes of current & voltage waveform there by affecting the overall power quality. In this work, it is concluded that Variable Frequency Drives introduce harmonics that affect the current signal waveform and increase Total Harmonics Distortion (THD). The results showed that by placing a three phase harmonic filter in the circuit where VFD is used for speed control of motor the THD is reduced considerably. This method of eliminating harmonics is a very cost effective and robust. It is also applicable in industries where VFDs are used for motor speed control especially higher rating motors.