FOPDT model and CHR method based control of flywheel energy storage integrated microgrid

Area of Science:

• Electrical Engineering
• Control Systems
• Renewable Energy Systems

Background:

• Islanded microgrids face frequency instability due to fluctuating loads and distributed generating units (DGUs).
• Maintaining frequency stability is crucial for reliable operation, especially in renewable energy-powered microgrids.
• Existing control strategies often struggle with the dynamic nature of these systems.

Purpose of the Study:

• To design and validate a Proportional Integral Derivative (PID) controller for enhancing frequency stability in islanded microgrids.
• To investigate the effectiveness of the Chien-Hrones-Reswick (CHR) tuning method for PID controllers in microgrid applications.
• To demonstrate the controller's performance in handling load disturbances and setpoint tracking.

Main Methods:

• A linearized transfer function model of an islanded microgrid, including DGUs and a flywheel energy storage system (FESS), was developed.
• The model was approximated to a first-order plus time delay (FOPTD) form for PID controller design.
• PID controller parameters were tuned using the CHR method, optimizing for 0% and 20% overshoot in setpoint tracking and load disturbance rejection.

Main Results:

• The CHR method, particularly for load disturbance rejection with 20% overshoot, proved superior to other tuning approaches.
• Real-time simulations and frequency analysis confirmed the proposed PID controller's effectiveness in stabilizing microgrid frequency.
• Transient responses demonstrated the controller's ability to mitigate oscillations under varying conditions.

Conclusions:

• The proposed PID control strategy, tuned via the CHR method, offers a robust solution for frequency stabilization in islanded microgrids.
• The FOPTD approximation and CHR tuning provide an efficient and analyzable approach for PID controller design in microgrids.
• The validated method enhances the reliability and performance of renewable energy-based islanded microgrid systems.