An adaptive notch filtering approach for harmonic and reactive current extraction in active power filters

This paper introduces a new adaptive notch filtering (ANF) approach for extraction of harmonic and reactive current components for use in active power filters (APFs). The main function of this method is to provide synchronized harmonic and reactive current components for the control purposes. The proposed method can successfully detect and track the variations in the frequency of the measured signal and extract the time-varying harmonics. The theoretical analysis is presented and the performance of the method is evaluated by applying it to a shunt APF. The methodology is applicable as a basis for detection of the reference signals in a wide range of equipments such as uninterrupted power supplies, regenerative converters, etc.