Using magnetizing reactances of transformer in hybrid active power filter

A hybrid active power filter (HAPF) topology which is appropriate for high-voltage grid is proposed. The passive filter of this topology consists of capacitors and 3-phase transformer (YnYn). Magnetizing reactances of transformer are used in passive filter, tuning with capacitors at 5th harmonic order frequency. The active power filter (APF) is connected in series to transformer and capacitors. This connection cause greatly to reduce the voltage rating of APF. Because of this advantage, proposed topology is effective to be used in the high-voltage distribution grid. The basic principle of this topology is introduced briefly. Then, the steady state compensation characteristic and the resonance-damping characteristic of this topology are analyzed in detail. The principle of the designing method of HAPF is also given. The proposed HAPF was simulated and results of the simulation are provided to validate the topology and the design considerations.