Dynamic modeling and control of an AC-link dynamic voltage restorer

This paper introduces the dynamic modeling along with a control strategy for a novel dynamic voltage restorer (DVR). This DVR is realized using phase-shifting transformers, an AC-link, and a vector switching matrix converter as building blocks. It has the ability of independently and selectively generating positive as well as negative sequence voltages, and hence it can compensate for different kinds of sags. The dynamic model along with a feedback controller design procedure are discussed in detail. Experimental waveforms under closed-loop regulation using a laboratory prototype are presented in order to validate the approach.