A novel structure for parallel hybrid active power filters with series resonant circuits

This paper presents a new parallel hybrid active power filter (HAPF) topology, which is suitable to suppress harmonic currents and compensate reactive power simultaneously in high-or medium-voltage power systems and can reduce the VA rating of the active power filter (APF) greatly. Based on the conventional topology of the parallel HAPF, the new structure includes a resonant circuit with a small inductor in parallel with APF controlled as harmonic current source, in order to force the fundamental reactive current to flow through the additional inductor, instead of flowing through APF. Furthermore, the APF need not withstand harmonic voltage due to the passive power filter is designed well-tuned in the new topology. So the VA rating of the APF is reduced greatly. Simulation results prove that the proposed parallel HAPF is good in harmonics elimination, reactive power compensation, and reliability.