Filtering of harmonic currents and damping of resonances in power systems with a hybrid-active filter

A novel hybrid-active filter topology to minimize electric utility current harmonics at high power levels is presented in this paper. The proposed topology combines both passive and active filters to obtain the lowest power converter VA rating as compared to the power converter rating in the active filter and the series-active hybrid filter configurations. This is demonstrated with experimental results from a laboratory model. Transient and steady state operation of the hybrid-active filter is also presented. The control of the proposed filter is extended to provide damping of resonances due to neighboring loads. Simulation results showing the effect of active damping are presented