Model Predictive Based Control of Wind Turbine Blade Pitch Angle

Abstract

The utilization of wind energy has become increasingly crucial in the energy composition of numerous countries and is projected to continue expanding in the forthcoming years. Wind turbine control has evolved into a crucial element within contemporary wind turbine systems. However, wind energy has emerged as a promising and sustainable source of power generation, but the intermittent and unpredictable nature of wind presents significant challenges for efficient and reliable operation of wind turbines. When the strong wind appears, power fluctuation is occurred, this leads to damage many materials. Accurately predicting and effectively managing the output power of wind turbines is crucial to mitigate the adverse impacts caused by excessive power fluctuations on both the wind turbine itself and the power grid. It is essential to ensure proper planning and control measures are in place to maintain stable and reliable operation. Since the wind turbines are nonlinear systems, the blade pitch angle plays a crucial role in capturing the maximum energy from the wind and ensuring safe turbine operation. This thesis developed a control strategy that maximizes energy extraction from the wind while maintaining the structural integrity of the turbine. Model predictive control (MPC) has chosen as the foundation for this approach due to its ability to handle complex and uncertain dynamics inherent in the wind turbines. To investigate the regulation of the pitch angle in a wind turbine, a comprehensive mathematical model encompassing all the system's elements has constructed. To facilitate simulation, the MATLAB software tool is utilized to develop the pertinent models. The MPC controller achieves a maximum pitch angle of 1.57 radians or 90 degrees. In the case of wind speeds ranging between the cut-in and rated speed, the pitch angle needs to be adjusted based on the prevailing wind speed. When the wind speed reached at nominal values, the pitch angle maintained at 0 radian. The generator speed settling time of PI is 1.3461 sec and rise time is 0.0806 sec. The generator speed settling time of MPC is 1.1995 sec and rise time is 0.0803 sec. The highest overshoot generator output power for PI is 5.035 MW which means 0.70% above the rated speed. The highest overshoot generator output power for MPC is 5.0145 MW which means 0.29% above the rated speed. In general, the MPC controller shows the higher quality stability of output power.