New hybrid parallel active filterconfiguration minimising active filter size

The authors propose a new topology for a hybrid parallel active filter that can further reduce the active filter (inverter) power rating. The basic idea is to install the active filter in parallel with the passive filter inductor. One advantage of this is that the passive filter can operate by itself if the inverter is in the high-impedance mode. This means that the passive filter can operate without the aid of the active filter. Another advantage is that, because the significant portion of fundamental and harmonic components flows through the passive filter, the current loading to the inverter is reduced greatly. This contributes to reducing the cost of the expensive inverter, and, hence, this makes the application of a hybrid active power filter more feasible. Through computer simulations and experiments, the authors have verified the effectiveness of the proposed topology.