Comparative Performance Study of Dynamic Voltage Restorer Employing Various Conventional Control Approaches

Voltage sag poses a prominent and frequent occurring power quality (PQ) issue for a 3-phase distribution system (DS). When integrated in series between the grid voltage and the load, a Dynamic Voltage Restorer (DVR) can effectively shield the load from voltage aberrations, with or without an injection transformer. This study explores the application of a DVR equipped with a suitable control algorithm as an ideal solution for mitigating voltage sags. The study involves modeling a benchmark 3-phase DS incorporating a capacitor-supported voltage source converter (VSC) as the DVR. Various conventional control strategies, including unit template (UT), synchronous reference frame (SRF) theory, and instantaneous reactive power theory (IRPT) with PI controllers, are employed for sag mitigation. The proposed DVR control approaches are thoroughly examined through simulated results in the MATLAB environment to conduct a comparative performance study under various sag conditions.