A hybrid active filter for damping of harmonic resonance in industrial power systems

This paper proposes a hybrid active filter for damping of harmonic resonance in industrial power systems. The hybrid filter consists of a small-rated active filter and a 5th tuned passive filter. The active filter is characterized by detecting the 5th harmonic current flowing into the passive filter. It is controlled in such a way as to behave as a negative or positive resistor by adjusting a feedback gain from a negative to positive value, and vice versa. The negative resistor presented by the active filter cancels a positive resistor inherent in the passive filter, so that the hybrid filter acts as an ideal passive filter with infinite quality factor. This significantly improves damping the harmonic resonance, compared with the passive filter used alone. Moreover, the active filter acts as a positive resistor to prevent an excessive harmonic current from flowing into the passive filter. Experimental results obtained from a 20 kW laboratory model verify the viability and effectiveness of the hybrid active filter proposed in this paper

Digital Object Identifier: 10.1109/PESC.1998.701901
Published with permission from the copyright holder. This is the institute's copy, as published in Power Electronics Specialists Conference, 1998. PESC 98 Record. 29th Annual IEEE, 17-22 May 1998, Volume 1, Pages 209-216.
Publisher URL:http://dx.doi.org/10.1109/PESC.1998.701901
Copyright © 1998 IEEE. All rights reserved.