Delay-Dependent Stability Analysis of Load Frequency Control Systems With Electric Vehicles

Area of Science:

• Electrical Engineering
• Control Systems
• Power Systems

Background:

• Load frequency control (LFC) is crucial for maintaining power system stability.
• Integrating electric vehicles (EVs) introduces complexities like uncertain parameters and time delays into LFC systems.
• Accurate stability analysis is essential for reliable grid operation with high EV penetration.

Purpose of the Study:

• To investigate delay-dependent stability for a one-area LFC system incorporating EVs.
• To develop novel closed-loop models for the LFC system with EVs, considering state of charge and parameter uncertainties.
• To derive accurate admissible delay upper bounds (ADUB) for enhanced system stability.

Main Methods:

• Development of two closed-loop LFC system models with EVs: one using model reconstruction and another with uncertain parameters.
• Application of the Lyapunov-Krasovskii functional method for stability analysis.
• Derivation of delay-dependent stability criteria to determine the ADUB.

Main Results:

• Two delay-dependent stability criteria were established for the LFC system with EVs.
• The proposed methods yield a more accurate ADUB compared to existing approaches.
• Case studies demonstrated the interrelationship between ADUB, PI controller gains, and EV parameters.

Conclusions:

• The developed models and stability criteria effectively analyze the delay-dependent stability of LFC systems with EVs.
• The findings provide valuable insights for designing robust LFC controllers in power grids with significant EV integration.
• Accurate ADUB determination is critical for ensuring the stability and reliability of power systems with EVs.