This document summarizes various techniques for improving power quality in grid integration of small-scale photovoltaic systems. It discusses PI-based reactive power control systems, flicker logistic control methods, automated filtering mechanisms, shunt active power filters, grid synchronization techniques, and integrated optimization-based AI techniques. For each method, it explores the benefits and limitations, and provides a comparative analysis of their effectiveness in addressing issues like voltage fluctuations, harmonics, and flicker. The review also highlights future research directions and challenges in implementing these techniques to enhance power quality in grid integration of small-scale photovoltaic systems.