Design considerations when applying various ASD topologies to meet harmonic compliance

In order to limit the harmonic distortion produced by Adjustable Speed Drives (ASD´s), manufacturers have introduced several methods of both passive and active harmonic mitigation. Users of ASD´s however, who are faced with the various options often find it difficult to select the most appropriate one for their particular application. Using computer simulation and laboratory measurements, this paper analyzes the most common passive solutions which include AC line reactors or DC link chokes, phase shifting to produce multi-pulse ASD´s and inline passive harmonic filters. Various design considerations, particularly related to power system parameters, are addressed.