Self-Tuning Controller of Active Power Filter in an Industrial Power System

The procedure for calculating controller parameters of an active power filter (APF), which is implemented into a multibus industrial power system for harmonic voltage mitigation, is presented. The node voltage detection control strategy is applied and the controller basic gain is found, taking into account required values of THDs of voltages at the bus-bars of the system and RMS values of the APF current. The structure of a self-tuning controller of the APF is proposed as well. The controller assures that the real APF current is hold in a proper range regardless the changes in operation modes of harmonic current sources in the power system.