TWO-STAGE GRID CONNECTED PHOTOVOLTAIC SYSTEM WITH UPQC APPLIED TO AC MICROGRIDS

Recently there is a rapid increase in exploring the potential in renewable energy sources(RES) like solar, wind etc. Because of the abundance of solar energy, the interest in installing solar power generation systems are accelerating day by day. As a result, large number of photo-voltaic(PV) systems are getting interconnected with utility grid. Due to high penetration of PV power to grid, energy regulatory bodies are imposing strict grid codes to maintain the power quality at the PCC. This paper discusses the detailed modeling and control strategies adopted for three phase two stage photo-voltaic unified power quality conditioner (2SPV-UPQC) connected to micro grid. Besides injection of active power into the grid, the series compensator of the 2SPV-UPQC system compensates for the power quality problems in grid such as load unbalancing, voltage sags/swells, harmonics etc. The proposed system combines both the benefits of improving power quality and clean energy generation.In this paper, a 50 KW system is simulated in MATLAB/Simulink software and the proposed control is illustrated using various case studies. Different power quality issues and along with associated remedies are discussed. The results obtained demonstrate the ability of the proposed system to improve power quality in microgrids.