Experimental Validation and Comparisons of Active Filtering Strategies.

Abstract

This paper deals with different active filtering strategies and digital techniques that can be applied to their implementation. The central idea is based on an alternative method to evaluate the disturbing voltage and current components through selective decompositions. Those decompositions, applied directly on voltage and current signals, are used to identify the distorting, unbalancing and non-active components and can be used to compensate either non-active power, power oscillations, harmonics and asymmetries in a different way as provided by the well known pq Theory. Four compensation strategies are discussed and compared for solving typical power quality problems. Simulation and experimental results illustrate the main differences among them, when facing non-linear, unsymmetrical and variable loads under generic voltage conditions. According to these results, a shunt active filtering is even capable to improve the PCC voltages under critical conditions or can allow full compensation of a set of chosen harmonics, even if the active filter has limited bandwidth.