Power Quality EnhancementInGrid-Connected PV SystemsUsing Gaussian Membership Function Type II Fuzzy LogicControllerAndDynamic Voltage Restorer

Power quality is a critical concern in modern electrical grids, particularly with the increasing integration of grid-connected photovoltaic (PV) systems. Voltage sags and swells, which are common disturbances in such systems, can significantly impact the stability and efficiency of power supply. This paper introduces an advanced approach to enhancing power quality in grid-connected PV systems by employing a Type II Fuzzy Logic Controller (FLC) with Gaussian membership functions and integrating a Dynamic Voltage Restorer (DVR). The Type II FLC is specifically designed to handle the inherent uncertainties and nonlinearities in PV systems more effectively than traditional controllers. By utilizing Gaussian membership functions, the controller offers precise and adaptive control, addressing the variations in solar power output and grid conditions. The DVR complements the FLC by injecting compensating voltage to mitigate disturbances such as voltage sags and swells, ensuring a stable voltage profile at the point of common coupling (PCC). Simulation results demonstrate a significant enhancement in power quality, with a reduction in total harmonic distortion (THD) by approximately 35% and voltage sags and swells mitigated by up to 45%. This study provides valuable insights into advanced control strategies, showing that the proposed system significantly improves the overall performance and reliability of PV systems, thereby contributing to the maintenance of optimal power quality in renewable energy grids.   Keywords-Dynamic Voltage Restorer (DVR), Grid-Connected PV Systems, Power Quality, Type II Fuzzy Logic Controller, Voltage Sags and Swells, Optimization Techniques.