Comparative analysis between classical and third-order sliding mode controllers for maximum power extraction in wind turbine system

Introduction. Maximizing power extraction in wind energy conversion systems is crucial for efficiency but remains a challenge due to rapid wind speed variations and the high inertia of the generator. Conventional controllers, such as the PI controller, struggle to maintain optimal performance under such dynamic conditions, leading to suboptimal power capture and increased system oscillations. The goal of this study is to enhance the efficiency of wind turbine systems by applying linear and nonlinear controllers in a maximum power point tracking (MPPT) strategy. This approach focuses on improving generator speed regulation and power conversion performance. Methods. A comparative analysis is conducted using three different control strategies: third-order sliding mode control (TO-SMC), classical sliding mode control (SMC) and PI control. These controllers are implemented in the generator speed loop of a wind turbine system, and their performance is evaluated through MATLAB/Simulink simulations. The assessment focuses on key performance metrics such as tracking accuracy, total harmonic distortion (THD), response time, and system stability. Results. The simulation results confirm that all controllers achieve MPPT, but with varying levels of effectiveness. The TO-SMC outperforms both SMC and PI controllers, offering higher efficiency, reduced chattering, better disturbance rejection, and lower THD (reduced from 73 % in SMC to 68.09 %). Additionally, TO-SMC significantly improves dynamic response, reducing overshoot and enhancing system stability. Originality. This study introduces a TO-SMC for MPPT in wind turbine systems, demonstrating its superiority over conventional control techniques. The findings highlight its ability to maintain optimal power extraction even under rapid wind variations, making it a promising solution for advanced wind energy systems. Practical value. By improving power quality, reducing system oscillations, and enhancing overall wind turbine efficiency, the proposed TO-SMC contributes to the reliable integration of wind energy into power grids. These advancements can benefit renewable energy operators, power system engineers, and researchers seeking efficient and robust MPPT solutions for wind turbines. References 13, figures 11.