Fuzzy Logic Based Proportional Integral with Anti-windup Dynamic Control of Grid-Tied Microgrid (Case Study: ASTU Student Cafeteria)

Abstract

Economic aspects, environmental issue, social and technical aspects are key factors for revolution of electric grid to develop microgrid. The grid tied microgrid consisting of solar photovoltaic system and battery energy storage system is modelled to support load without interruption. The frequency and voltage fluctuation are major problems in a grid tied microgrid due to intermittent nature of solar photovoltaic system while battery energy storage system acts as a master unit which is responsible for setting up the voltage and frequency at the point of common coupling by balancing active power. This research work focuses on active power regulation, frequency and voltage control at the point of common coupling between microgrid and utility grid. Microgrid needs good frequency dynamic performance, good voltage amplitude dynamic performance and well regulated active power at the point of common coupling. Microgrid components are analyzed by using MATLAB/Simulink. Mathematical modelling of the proposed system is performed. Fuzzy logic based proportional integral with anti-windup and proportional integral anti-windup voltage and current controllers are designed to control the current and voltage output of three phase three level neutral point clamped voltage source inverter connected to battery energy storage system, utility grid and loads at the point of common coupling. Fuzzy logic based Proportional integral (PI) with anti-windup and PI anti windup controller are compared based on their dynamic frequency performance and dynamic voltage amplitude performance during different operation mode of microgrid. Fuzzy-PI anti-windup gives settling time of 12:00 hour of frequency with overshoot of 0.1976% per 50Hz in a grid connected operation of microgrid with varying solar irradiance at point of common coupling. But, PI anti wind up results settling time of 12:30 hour with overshoot of 0.1997% for the same conditions. Also, Fuzzy-PI anti windup gives settling time of 3.97 minute of voltage amplitude with overshoot of 4.4634% in the same condition. But, PI anti windup results settling time of 4 minute of voltage amplitude with overshoot of 4.4766% in the same condition. The detailed analysis of microgrid dynamic operation control is performed by conducting three scenario. In all cases system parameters maintained within the acceptable range for stable operation of grid tied microgrid. In general fuzzy PI anti-windup is recommended for microgrid dynamic control.