Shunt active filters: selective compensation of current harmonics via state observer

This paper deals with partial current harmonics compensation by means of shunt active filter. A novel observer-based scheme is proposed to estimate load harmonics. This task is performed in d-q reference frame where active and reactive current components are enlightened. Positive and negative sequences are distinguished for selective compensation. Predictive action can be generated using the proposed observer to improve current tracking performances. Experimental results are presented to show the effectiveness of this technique.