SPLL based control for active filter with reactive power compensation

This paper presents a single phase shunt active power filter with reactive power compensation. The employed control method combines the functionality of a feedforward active filter with the functionality of a shunt connected static compensator (STATCOM). Both to extract the load harmonic currents for active filtering and to measure the phase angles for reactive power compensation a novel software phase locked loop (SPLL) is employed. The SPLL architecture has two interconnected control loops, an amlitude controller and a phase angle controller, which provide a quick measure of amplitude, frequency and phase angle of the input signal, even for low amplitude signals. Moreover adaptive techniques employed in the SPLL make it quasi inmune to white noise and give it an excellent harmonics cancellation. The other features of the whole control as the current control loop, the dc-link capacitor controller and the reactive power compensation are widely explained too. Simulation and real time implementation results are presented to verify the performance of the model.