Active filtering of harmonic currents in three-phase, four-wire systems with three-phase and single-phase nonlinear loads

A novel active harmonic-neutralizing filter is proposed which eliminates current harmonic effects, caused by any configuration of nonlinear loads in a three-phase, four-wire systems. The authors present proposed filter topologies and simulation results verifying the concept. Theoretical analysis of the circuit is included to facilitate a detailed converter design. The proposed topology is shown to have distinct advantages over traditional approaches to the problem, particularly over the three single-phase inverter approach