Um restaurador dinâmico de tensão para correções de variações de tensão de curta duração em redes elétricas.

Abstract

This work proposes a methodology for restoring power system load voltages capable of deal- ing with unbalanced voltage sags and swells. The method makes use of a four-leg inverter based dynamic voltage restorer (DVR) in which the positive and the opposite of the neg- ative sequences are injected through three legs and the opposite of the zero sequence by the fourth one. The positive and negative sequences are computed by means of a digital scalar modulation whilst the zero one is generated by an alternative modulation technique. Also, it is presented an algorithm for estimating the sequence components in real-time. A collateral contribution arises from the application of these components in a feedback con- trol which improves the short duration voltage variation correction. In order to validate the methodology, a laboratory-scale dynamic voltage restorer was developed and a digital signal processor (DSP) carried out all signal acquisitions, control algorithms, generation of the PWM signals and voltage and current measurements. Experimental tests producing voltage sags and swells were analyzed and the results show the e ectiveness of the proposed methodology.