Energy Management System Based on Fuzzy fractional order PID Controller for Transient Stability Improvement in Microgrids with Energy Storage

The need to reduce greenhouse effect using distributed energy resources (DER) has significantly increased in recent years, particularly with the advent of deregulated
market. Climate changes causes large swings in output power of renewable resources and the resulting fluctuations in frequency in the islanded Microgrid (MG).
To increase performance for a wide range of power system operating conditions, an energy management systems (EMS) is proposed based on a fuzzy fractional order
PID (FFOPID) controller. It is able to analyze and simulate the dynamic behavior in grid connected MGs. This controller is proposed in the MG encompassing
distributed generation resources with “plug and play” ability. The performance of FFOPID controller is verified for frequency control purposes and to support internal
bus voltage in both islanded and grid connected operating modes in accordance with the failure time. Energy storage (ES) is used to improve the system dynamic response,
reduce the distortion and provide damping for frequency oscillations caused by renewable resources. ES overload capacity is utilized for rapid initial control of
frequency in MG. To achieve this goal, EMS based on fuzzy decision mechanism combined with a PID-controller (termed as FLPID) and Fuzzy fractional order PID
(termed as FFOPID) are implemented according to the characteristics and limitations of overloading and state of charge (SOC). The obtained results show good
performance of FFOPID controllers by improving the transient stability following a fault that has caused the islanded operation. Simulation results have validated
the effectiveness of FFOPID controllers in the system under several scenarios with superior stabilization and more robustness in comparison with the FLPID and PID
controller.