Harmonic Filtering in Variable Speed Drives

This paper discusses and presents results related to still open controversial issues in passive harmonic filters design, such as the identification of filter resonant frequencies, the effects of interactions of harmonic filters with system impedances and the importance of damping elements. Benefits of passive rectifiers equipped with harmonic filters are compared to those of other rectifier front-ends typically used in VSD applications. An experimental comparative evaluation of harmonic performances of passive and active rectifiers is also provided.