Robust H-infinity and μ-synthesis controllers to mitigate sub-synchronous control interaction in DFIG wind farms considering time delay

Wind power has rapidly emerged as a leading renewable energy source, with doubly-fed induction generators gaining attention for their independent power control capability. Integrating doubly-fed induction generator-based wind farms into the grid requires significant upgrades to transmission and distribution infrastructure to fully harness wind energy’s potential and address challenges like sub-synchronous control interaction. This phenomenon poses risks such as equipment damage and power supply interruptions. To mitigate these risks, a novel adaptive control strategy incorporating uncertainty and disturbance estimators, alongside H∞ and μ-synthesis controllers, is proposed. By introducing a time delay into the control system, oscillations can be detected and stabilized, ensuring system stability across various operational conditions. The controller parameters are optimized using a dynamic opposite learning-based enhanced mountain gazelle optimization algorithm. This algorithm is utilized to determine the optimal controller parameters that ensure system stability across different operational conditions. Simulation results conducted in MATLAB validate the effectiveness of the proposed controller in damping oscillations under different compensations and wind speeds. Specifically, it demonstrates superior damping capabilities at various wind speeds and compensations, enhancing power system stability and reliability. Results confirm the better damping capability of proposed controller under different compensations such as 75% and 45% and wind speeds such as 13 m/s, 7 m/s, and 11 m/s. This research provides better stability and reliability of power systems by dampening oscillations at 1.5 s, ensuring the sustainable integration of wind energy.