FERNANDES, D. A.; http://lattes.cnpq.br/4875481653656310; FERNANDES, Darlan Alexandria.
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.