Active filters for the improvement of electric power quality

In this paper the application of the active EMI filters in order to solve practical utility problems and to improve the electric power quality are presented. Electrical distribution system components are designed to operate at the standard 50 or 60 Hz frequency. However, many loads found in industrial and residential settings demand currents that have frequency components with multiples of the 60 Hz fundamental. The most common effect of harmonic load currents is heating. The increased temperature reduces rating of equipment and operating performance. In extreme cases failure of equipment may occur. The results demonstrate that although the larger components, differential-mode capacitors and common-mode inductors, may be needed for attenuation at the fundamental frequency, their effectiveness becomes very limited at higher frequencies due to parasitics.