Improvement for the closed-loop control of shunt Active Power Filter

The Active Power Filter harmonic compensation system based on supply-side current detection method, because of its closed-loop in essence would have a certain suppression for phase delay and resonance of the system, but closed-loop gain too great will lead instability of the system, which not only influence the effect of harmonic compensation, but also lose the aforementioned advantage. Previous papers enhanced stability margin so as to increase loop gain by adding phase lead correction to the system, however, the improvement of compensation effect is limited. The reasons for hindering further improve of the effectiveness compensation is found out and which is improved in this paper, its effectiveness is verified by the results of experiment.