Digital non-linear controller-based active power filter for harmonic compensation

AbstractThis paper presents a design and implementation of digital non-linear controller-based, three-phase shunt-active filter for power line conditioner system. The active power filter is implemented with PWM-Voltage Source Inverter and its switching pulses are generated from Space Vector Modulation techniques. The active filter is applied for power quality improvements by compensating harmonics in the distribution network due to non-linear loads. The harmonic components are extracted from the sensed load currents from proposed non-linear control strategy. A simple and efficient Phase Locked Loop is used to synchronize the angle of vector orientation, which cancels the effect of harmonics and notches in the distribution network. An inner and outer loop Pl-control is incorporated with non-linear method for harmonic current control and dc-bus voltage regulator. Additionally, pre-filter is inserted at the input of each current loop in order to compensate for the effect of the left hand zero in the closed l...