Passive, active and hybrid filters as a part of the energy efficient electrical drives curriculum

Power quality problems such as voltage, current or frequency deviation of the supply system, are more and more recognized as the source of failures or mal-function of electrical equipment. Electronically controlled, energy efficient modern industrial and commercial electrical consumers, due to enclosed power electronics devices act as non-linear loads and generate power quality problems. Also, they present the most sensitive equipment to deviations in the supply system. Different filtering solutions and techniques have been analyzed, tested and implemented throughout the recent years. This paper analyzes performance of series and parallel passive filters, active filter with open-loop and closed-loop control and selected hybrid power filter topology using computer simulation. As a consequence of variable speed drives application with a diode bridge as an input rectifier unit, grid current harmonics are introduced. The aim of this paper is to present how students can get familiar with the basic harmonics mitigation techniques trough simulation models. Hence, the responsible application of modern controlled electrical drives is promoted, considering the power quality requirements, thus comprising the entirety called energy efficient electrical drives.