Adaptive active power filter for power quality improvement under random load variation

This paper presents new control strategies to improve the dynamic behavior of the shunt active power filter operated under random load variation. In these strategies a feedback of load value is applied to control system through linear and non-linear functions to regulate the output of conventional PI controller. Employing these strategies, the active power filter compensates harmonics and reactive power generated by the nonlinear-load simultaneously and will be robust under fast load variation condition. The proposed control strategies are tested and compared for wide range of variable load current and results are found to be quite satisfactory to mitigate harmonics and reactive power components from the utility current especially when non-linear feedback is connected.