Study of Active Power Filter Control Strategy based on Improved P-Q Harmonic Current Detection

The traditional harmonic current detection algorithm has large compensation current error when the three-phase voltage is asymmetric or the load changes abruptly. In order to solve the problem, an improved P-Q harmonic current detection method is used in this paper, which is suitable for both three-phase voltage symmetrical system and asymmetric system. Based on the analysis that the harmonic current of power system is mainly 6k ± 1 , the controllers of multiple proportional resonance (QPR) and PR+ fast repetitive control are used. The comparison shows that active power filter with improved P-Q harmonic current detection and PR+ fast repetitive control has the advantages of good harmonic compensation effect and fast dynamic response.