Enhanced Robustness of Sliding Mode Control For DFIG-Based Wind Energy Systems Under Grid Faults and Wind Variations

Abstract

This work presents an enhanced Sliding Mode Control (SMC) scheme for wind energy 
conversion systems with Doubly Fed Induction Generators (DFIGs). The proposed 
control ensures accurate, current regulation and disturbance rejection under parameter 
variations and grid disturbance. Due to its inherent complex structure and nonlinear 
operations, DFIG systems are vulnerable to losing stability and poor performance under 
internal or external disturbances. The modern grid code lays strict rules to ensure 
stability even under disturbances. This work employs an integral sliding surface design to 
tackle the impact on system performance under stator and rotor parameter variations 
and grid disturbances.  This control method integrates adaptive decoupling terms that 
effectively restrain cross-axis coupling and minimize chattering using a smooth 
saturation function. A detailed mathematical model, the system was simulated on the 
MATLAB platform under various dynamic conditions to confirm the effectiveness and 
performance of the novel SMC. The simulation results validate the enhanced performance 
of the proposed controller under voltage sag and swell and wind gust-induced torque 
variations. These results satisfy compliance with low voltage ride-through (LVRT) 
requirements in quick error convergence, lower chattering, and stale voltage adaptation.  
The enhanced SMC maintains bounded control inputs, reduces overshoot, and 
significantly improves disturbance rejection, making it a reliable choice for wind energy 
integration.