Design of a direct control strategy for a static shunt compensator to improve power quality in polluted and unbalanced grids

Abstract Many control techniques for three-phase active filters with the aim of improving the power factor and reducing the current harmonic distortion at the source level exist today and are widely reported in the scientific literature. Almost all of these methods are designed for a perfect sine-wave source and do not perform sinusoidal current when voltages are distorted or unbalanced. The work developed in this paper concerns the active filtering on a perturbed and unbalanced network. First, the proposed control method is described and validated by simulations and experimental results, and then the proposed method is compared to the classical control laws such as the original p-q theory, the modified p-q theory and the p − q − r method. Experimental results are conducted on a three-wire low power distribution network under perturbed voltage and non-linear load using a DSPACE control system. The assessment is performed on the source currents after filtering, and a comparative evaluation in terms of unbalance factor and current Total Harmonic Distortion ( THD i ) is carried out for all methods.