Multi-stage sliding mode control design with optimal state estimator for load frequency regulation in hybrid-source...

Area of Science:

• Electrical Engineering
• Control Systems Engineering
• Renewable Energy Systems

Background:

• Modern power systems (PSs) face challenges in automatic load frequency control (LFC) due to high renewable energy source (RES) penetration, leading to uncertainties and reduced inertia.
• Conventional LFC strategies struggle with the complexity and disturbances inherent in hybrid power systems (HPSs), impacting stability and reliability.

Purpose of the Study:

• To develop a robust LFC scheme for multi-area HPSs integrating diverse energy sources, including RES and energy storage.
• To enhance system stability, reliability, and dynamic response under uncertain operating conditions and disturbances.

Main Methods:

• A novel multi-stage sliding mode control (SMC) scheme was designed, incorporating an optimal state estimator (OSE) for accurate state feedback.
• A new multi-term sliding surface was formulated to ensure fast dynamics and resilience against system uncertainties.
• Mathematical stability validation and extensive simulations were conducted under various scenarios, including communication delays.

Main Results:

• The proposed OSE improved control robustness under uncertain conditions.
• The multi-stage SMC scheme demonstrated superior performance compared to existing methods, reducing overshoot/undershoot significantly.
• Settling time was reduced by up to 23.8%, and control signal chattering was eliminated.

Conclusions:

• The proposed LFC scheme offers enhanced robustness, reliability, and practical applicability for complex HPSs with high RES integration.
• The controller effectively manages uncertainties and disturbances, ensuring stable and reliable power system operation.
• This approach is well-suited for future power grids with increasing reliance on renewable energy.