Aerodynamic Efficiency Optimization And Control Of 1.5MW Wind Turbine

The objective of wind turbine development nowadays is high energy efficiency and high reliability.The efficiency of wind turbine is mainly determined by the aerodynamic efficiency and the control strategy during operation.Therefore,a series of researches on aerodynamic efficiency and control strategies of wind turbine is implemented.The correction model of BEM with introduced the cone angle ? is proposed based on the traditional BEM theory,which can not be used to optimize the cone angle.And the cone angle of 1.5MW wind turbine with NACA0012 airfoil is optimized with corrected ?-BEM.The results show that the power coefficient has been further improved.A viewpoint is proposed and confirmed that "the best angle of attack" for obtaining maximum power coefficient of a wind turbine is actually larger than "the maximum lift-to-drag ratio angle of attack",because the current situation that "the maximum lift-to-drag ratio angle of attack"is applied in the angle of attack design and the control strategy of wind turbine generally,but the wind turbine is different from structure and energy conversion mode of the aircraft.The differential model for optimizing the angle of attack is build first,then an example of "the best angle of attack" is implemented and analyzed.Finally,the effects of the cone angle and the effects of the torque control under variable wind conditions on the best angle of attack is analyzed.The results show that the power coefficient is significantly improved.An improved MPPT control strategy based on optimal regression path is proposed,for the traditional MPPT control strategy does not take the effects of the regression path on the output power into consideration.Based on the traditional MPPT control process,pitch control is introduced to optimize the regression path of the working point of the wind turbine.The reference value of pitch angle is determined by ?-BEM correction model with the secondary search algorithm in real time to maximize the output power of the wind turbine during the MPPT process.The regression paths are optimized for step reduction,step increase and turbulent wind respectively.The results show that the output power of the wind turbine has been improved by the optimization.An Nonlinear Model Predictive Control(NMPC)controller has been designed to reduce tower load,blade load,pitch activity and to stabilize generator power by introducing future disturbance information into the nonlinear model predictive controller's optimal control strategy,aimed at the output power fluctuations.The result shows that the NMPC controller can suppress the fluctuation of output power under extreme continuous gust and turbulent wind conditions.