Hysteresis current controlled active power filter for power quality improvement in three phase four wire electrical distribution system

Three-phase four-wire (3P4W) electrical distribution systems are extensively utilized in commercial and industrial sectors. These electrical distribution systems are facing severe power quality issues such as current harmonics, reactive power, and load unbalancing, excessive neutral current. This paper presents the analysis, design and digital simulation of a hysteresis current controller (HCC) based active power filter (APF) to improve the power quality in a 3P4W electrical distribution system. In the present work APF is implemented with a 4-leg voltage source inverter (VSI) which is connected in shunt to the 3P4W electrical distribution system. The VSI switching signals are generated through a hysteresis current controller (HCC), which has good current tracking accuracy, unconditioned stability and easy implementation. The proposed HCC based APF compensates current harmonics, reactive power, and load unbalancing and neutral current in 3P4W electric distribution system feeding nonlinear and unbalanced loads. The performance of the HCC based APF is demonstrated using MATLAB© simulation.