Adaptive fuzzy-PI controlled dynamic voltage restorer for mitigating voltage sags

The rising integration of sensitive loads at the distribution level demands superior power quality and uninterrupted supply to prevent critical disruptions and financial losses. This study introduces a high-performance Dynamic Voltage Restorer (DVR) with an optimized control strategy to mitigate voltage sags caused by motor starting and short-circuit faults, addressing both magnitude and phase disruptions in the load voltage. A hybrid DC energy storage system, combining a supercapacitor and a proton exchange membrane fuel cell (PEMFC), is integrated through a multi-input single boost converter, governed by an intelligent energy management algorithm. This configuration ensures reliable support during both short- and long-duration voltage sags. To enhance dynamic response, a fuzzy gain-scheduled PI controller is employed, offering adaptive and robust voltage restoration. The system is validated on a low-voltage experimental setup featuring a three-phase double cage induction motor and a sensitive load. Results confirm significant improvements in voltage profile restoration and sustained system stability without over-modulation. The compensated scenario shows that the different sag indices reduce effectively, indicating near-elimination of sag severity. The proposed DVR solution demonstrates a scalable and resilient approach for modern power distribution networks facing increasing power quality challenges.