H-infinity Linear Matrix Inequality Robust Control Strategy for Doubly Fed Induction Generators (DFIG)

One critical research domain in power systems engineering involves developing advanced control strategies for doubly fed induction generators (DFIGs). DFIGs are predominantly utilized in wind energy conversion systems due to their superior capability to harness wind power across variable speed ranges compared to conventional generators. Among various control methodologies, H-infinity Linear Matrix Inequality (H∞ LMI) robust control has emerged as a extensively researched approach. This control framework employs LMI optimization techniques to design controllers that guarantee system stability and performance robustness against operational uncertainties and dynamic disturbances. The implementation typically involves formulating the control problem as a convex optimization task using MATLAB's LMI toolbox, where key functions like "hinflmi" or "hinfstruct" are employed to solve the H-infinity norm minimization problem. The algorithm establishes stability criteria through Lyapunov-based matrix inequalities, ensuring the DFIG maintains optimal torque regulation and power output under grid faults or wind speed variations. By integrating this robust control strategy, wind power systems achieve enhanced reliability through improved fault ride-through capability, superior power quality via precise reactive power compensation, and increased energy efficiency through optimized generator torque characteristics. Code implementation aspects include designing observer-based controllers that compensate for parameter variations in the DFIG model, with Simulink blocks simulating grid-side and rotor-side converter interactions. The control structure typically incorporates disturbance rejection modules and uncertainty modeling blocks to validate performance under IEC 61400-21 standard compliance tests.