The electric power generation systems are relatively affected by unbalanced, fault voltages and harmonic distortions in singlephase or three-phase systems. These abnormal conditions cause power quality problems and have severe influences on control of power conversion systems. This paper presents a comparative benchmarking of positive-negative sequence (PNS) extractor methods for reference current generation, sag/swell detection without time delay and eliminating oscillations on control signals. The performance comparisons of the sequence extractor are examined in terms of harmonics, unbalanced networks and startup. The selected PNS extractors are also applicable for control of single and three phase applications. The effectiveness and validation of the PNS extractors are examined in a power conditioner controller under various cases.

Keywords: Average filter, Positive and negative sequence extractor, Distributed generation, Power quality, Harmonic distortions