Intelligent frequency control in microgrid: Fractional order fuzzy PID controller

Due to integration of different distributed power sources in microgrid, power quality is adversely affected and has caused many control problems. Hence power system requires much more proficiency and adaptability in control and optimization to overcome these problems. The power quality issues in microgrid system are mainly from frequency fluctuations. In real scenario, frequency fluctuations happen because of impulsive variations in load/generation or both. This research study presents a Fractional Order Fuzzy PID (FOFPID) controller for frequency control in microgrid. To test effectiveness of proposed controller, its performance is evaluated and compared with standard PID and Fuzzy PID (FPID) controller. To find optimal parameters of the FOFPID, Gravitational Search Algorithm (GSA) is employed. To illustrate the effectiveness of GSA, its outcome is compared with existing algorithms such as Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) algorithms. Further performance of each controller and optimizing method is assessed by looking at the fitness function value, statistical data, frequency deviation, amplitude and oscillations of control signal. Finally, the most optimized algorithm-based controller is tested for robustness against parameter variations and nonlinearities like Generation Rate Constraint (GRC).