Reduced rating hybrid active power filter in a three-phase four-wire distribution system

In this paper, a new three-phase four-wire active power filter (APF) based on a zigzag transformer, three phase voltage source inverter (VSI) and single phase active power filter is proposed for power quality improvement. The proposed hybrid APF is used for the compensation of reactive power, harmonic currents, neutral current and load balancing at the point of common coupling. The zigzag transformer is used for providing a path to the zero-sequence current and compensates utility neutral current up to some extent. The single phase active power filter compensates the rest of the neutral current. The insulated gate bipolar transistor (IGBT) based VSI is supported by the inductor is controlled for the required compensation of the load current. The hybrid APF is tested for power factor correction along with neutral current compensation, harmonic elimination, and balancing of nonlinear loads. The performance characteristics of the three-phase four wire hybrid APF are validated using MATLAB software with its Simulink and power system block set toolboxes.