A Current Detecting Method for Reactive Power, Harmonic and Negative Sequence Based on Positive Sequence Extractor of Fundamental Wave

Whether the active power filters (APF) could or not get desirable harmonic eliminating effects according to the work principle, it mainly depends on the fastand accurate detecting method for reactive, harmonic and negative sequence current . After analyzing the selective frequency characteristic of amplitude integration signal, this paper addresses a positive sequence extractor of fundamental wave, and presents a novel current detecting method for reactive power, harmonic and negative sequence. This detecting method needs neither the phase locked loop (PLL) nor the low pass filters (LPF), and can omit some complex calculations for the coordinate transformations. Simulation and experiment results all verify the perfect filtering performance of this shunt APF which employs the novel detecting method.