Improved Microgrid Controller with Robust Stability, Conjunction with PID Controllers

Microgrids are gaining prominence as essential components of modern power systems, particularly in facilitating renewable energy integration and enhancing system resilience. However, the inherent complexity and dynamic behavior of microgrids present significant control challenges, including voltage stability, frequency regulation, and fault mitigation. This paper proposes an improved microgrid controller designed to ensure robust stability under varying and uncertain operating conditions. The controller integrates a Linear Matrix Inequality (LMI)-based design approach with Proportional-Integral-Derivative (PID) control strategies, enabling adaptive and efficient performance tuning. By employing the Lyapunov stability theory and Linear Quadratic Regulator (LQR) principles, the proposed controller minimizes control effort while maintaining system robustness in the presence of nonlinearities, parametric uncertainties, harmonic distortions, and dynamic load variations. Detailed modeling of both single-phase and three-phase microgrid systems is presented, incorporating critical components such as voltage source inverters (VSIs), LC filters, and transformers. The controller's design is validated through extensive simulations, evaluating its response to various real-world load conditions, including harmonic, non-linear, dynamic, asynchronous, and unknown loads. Results demonstrate the controller’s effectiveness in reducing Total Harmonic Distortion (THD), maintaining voltage and current stability, and enhancing system adaptability during faults and operational fluctuations. A comparative analysis with conventional controllers further underscores the improved controller's superior performance in ensuring stability and reliability. This study contributes a scalable and resilient control framework, well-suited for evolving smart grid environments and high-penetration renewable energy systems.