A novel active power filter for high voltage application

A new active power filter (APF) is proposed in this paper which combines the two mechanisms of harmonic tracking and cancellation as well as variable resistance. This strategy greatly reduces the requirement of the passive filter. A shunt resonant passive filter, which falls in resonance in the fundamental frequency and 6/sup th/ harmonics, is employed in this paper mainly to reduce the fundamental current loss of the HAPF. Simulation results demonstrate that the system can suppress harmonics from 2th to 20th with more than 20 dB attenuation and 10 Hz-30 Hz with approximately 20 dB. The HAPF expands the pass-band width of the PF, while demonstrates high impedance at fundamental frequency.