Non-linear adaptive fuzzy control for microgrid-integrated UPQC under severe disturbances

This work suggests the functionality of the grid integrated microgrid-based unified power quality conditioner (UPQC) system employing proposed reference generation scheme and proposed feedback compensator based current and voltage controller approach underneath extreme power system perturbations generated at the microgrid source owing to the fault originated during interfacing of renewable energy resources. The proposed methodology follows a three-stage approach. First, Takagi-Sugeno fuzzy (TSF) logic and adjustable proportional-integral-derivative (APID) control are coupled to make an adjustable non-linear gain fuzzy (ANGF) controller. In order to achieve minimal steady-state error, this controller controls the capacitor voltage variances within the UPQC during load and source variations. Second, an improved fuzzy phase-locked loop (IFPLL) based on Mamdani fuzzy principles improves the UPQC’s performance even under grid disruptions. Third, a modified synchronous reference frame (MSRF) system generates accurate current and voltage references for UPQC operation. In addition, the proposed feedback compensator benefits the UPQC system by improving tracking error deterioration, gain stability, and lessening amplitude deformation as well as sensitivity to exterior disorders. The effectiveness of the suggested control approach for UPQC is considered through evaluation with a conventional enhanced phase-locked loop (EPLL) and TSF- synchronous reference frame (SRF) controller and then justified via simulation and real-time HIL system under extreme power system environments such as voltage swell/sag along with distorted voltage, random fluctuation of load, voltage interruption, voltage unbalance, and under-voltage.