A resonance dumping control for a line-current detection type active filter

The active power filters with line current detection need fewer detectors than those with individual load current detection, though the former have harmonics resonance problems. To avoid these problems, we propose a novel control system consisting of a line characteristics identifier and a 2nd-order filter. The identifier provides the line frequency characteristics observed from the point of the active power filter. The parameters of the 2nd-order filter are determined according to the identified characteristics. We obtained good results of both simulations and experiments using a prototype model