Detection of harmonic and reactive currents for shunt active power filter

The compensation performance of active power filter(APF) strictly depends on the accurate detection of harmonic and reactive currents in the course of harmonic elimination by using APF.Due to the application of referenceframe transformation and inverse transformation to detect the harmonic and reactive currents,traditional detection method based on instantaneous reactive power theory gives more complexity in realizing the control circuit of the APF.Imaging the voltage of electrified wire netting is sine wave,a new method to detect the harmonic and reactive currents was proposed in this paper.Since the harmonic and reactive currents were determined in the a-b-c reference frame based on instantaneous reactive power theory,there was no reference-frame transformation requirement.Therefore the control circuit implemented by the proposed algorithm has been carefully simplified and facilitating the practicality of the method.Furthermore,this detection method has improved the real-time performance of compensation,because there was no phase lag caused by the low-pass-filter.The theoretical analysis and simulation verify the validity of this detection method.