Enhanced Power Quality Control in Grid Tied PVG-UAPF Systems Using a Modified Second Order Generalized Integrator and Notch Filter

In This paper presents a Modern grid-connected power system face serious power quality issues due to DC offsets, nonlinear load harmonics, and distorted grid voltages, leading to increased Total Harmonic Distortion (THD) and reduced system stability. Conventional controllers like the Second-Order Generalized Integrator (SOGI) and Enhanced SOGI (ESOGI) provide basic mitigation but struggle to balance harmonic filtering and fast dynamic response. This work proposes a Modified SOGI combined with a Notch Filter (MSOGI) in a Photovoltaic Generator–Unified Active Power Filter (PVG-UAPF) system to overcome these limitations. The proposed control method improves harmonic rejection, suppresses DC offsets, and compensates for both grid- and load-side disturbances while maintaining unity power factor. MATLAB/Simulink simulations and OPAL-RT real-time validations demonstrate the system's performance under dynamic conditions. The MSOGI-based approach achieves THD values of 1.85% for grid current and 2.04% for load voltage, ensuring compliance with IEEE-519 standards and proving its effectiveness for modern smart grid applications.by using matlab simulink software

Keywords: Notch filter (NF), modified second order generalized integrator (MSOGI), unified active power filter (UAPF), power quality (PQ), photovoltaic generator (PVG).