A Robust Stability Control Method Integrating Linear Quadratic Regulator and Proportional Integral for Islanded AC Microgrid

The Linear Quadratic Regulator (LQR) has been frequently employed for controlling islanded microgrids (MGs). However, it shows limited effectiveness in transient response regulation and resilience. To enhance the robustness and performance of three-phase inverters operating in islanded mode, a power-sharing control technique integrating Linear Quadratic Regulator (LQR) and Proportional Integral (PI) controllers is presented in this paper. Traditional Single Input Single Output (SISO) controllers are unable to handle transient responses and stability issues. The proposed hybrid LQR-PI control technique minimizes the quadratic value of power error and control inputs during transients while also optimizing robustness margins by including an adaptive tuning mechanism. The methodology involves a comprehensive analysis and application across multiple operational domains, which are used to develop a model that integrates voltage and current dynamics, as well as power sharing, in a synchronous reference frame. The proposed approach was thoroughly tested, and the suggested strategy demonstrates a significant reduction in settling time, as well as improved system responsiveness and stability. The results indicate that this hybrid control method is highly effective in providing precise and efficient control under varying operational conditions, as it ensures rapid convergence to the desired state with minimum overshoot. Under dynamic conditions, the research proposes a process for creating an islanded microgrid model in a synchronous reference frame, with robustness analysis confirming the stability of the LQR and PI controllers. The validation is conducted entirely in a Matlab/Simulink environment. This study is focused on simulation-based validation under ideal conditions. Simulation results validate the accuracy and efficiency of the proposed model and control technique, showing significant enhancements in transient response and robustness in islanded mode operations. It is very effective when requiring precise and efficient control under varying operational conditions since it guarantees rapid convergence to the desired state with minimum overshoot. Under dynamic conditions, the research proposes a process for creating an islanded microgrid model in a synchronous reference frame with robustness analysis confirming the stability of both controllers. The validation is conducted entirely in a Matlab/Simulink environment. This study focuses on simulation based validation under ideal conditions. Simulation results validate the accuracy and efficiency of the proposed model and control technique showing significant enhancements in transient response and robustness in islanded mode operations.