Reference Current Extraction through Sliding DFT Assisted Single Phase p-q Theory for Shunt Active Power Filter

Active Power Filters (APF) are more effective than conventional passive filters with regard to mitigating harmonics and compensating reactive power. As a result, deployment of APF in the distribution network is ever increasing. The performance of APF mainly depends on the reference extraction technique adopted. This work proposes sliding Discrete Fourier Transform (DFT) assisted single phase p-q theory for the extraction of reference current. The proposed algorithm exploits the inherent ability of sliding DFT (SDFT) to provide the fundamental and its quadrature component of signal (voltage or current) to derive the reference current with the help of a single-phase p-q theory. Furthermore, the algorithm involves the phase shifting of the fundamental component alone, and is suitable even for distorted utility voltage. Effectiveness of the proposed method is demonstrated through simulation results.