基于功率和载荷协调的变桨距控制策略

摘要

The ordinary pitch control strategy is that the pitch achieves the optimum torque when turbines start-up, and achieves constant power control while wind speed is above the rated. Generally, loads change caused by the variable pitch process will not exceed the threshold range under normal condition. However, load threshold may be decreased when equipments become ageing and fatigued, which do harm to wind turbine's security. Based on the establishment of mathematical model of wind turbine, the internal relationship between pitch angle and loads is analyzed , and pitch control strategies of power and loads coordination are proposed in the paper. When wind turbines are under overload operation, we can change ordinary pitch control strategy and adjust the pitch angle to ensure the operation of wind turbine's safety and stable. Using GH Bladed modeling and simulation, the feasibility and effectiveness of control strategy is proved by the simulation results.%风力机启动阶段变桨距实现最佳力矩,额定风速以上时变桨距实现恒功率控制.正常情况下变桨距过程引起的载荷变化不会超过设计阈值范围.但是,当风电机组设备老化疲劳后载荷阈值可能会下降,出现超载荷运行的现象,危害机组安全.本文在建立风电机组数学模型的基础上,分析了桨距角和载荷的内在关系,提出了功率和载荷协调的变桨距控制策略.当风电机组超载荷运行时,改变常规的变桨距控制策略,调整桨距角,优化变桨速率,以降低风电机组输出功率为代价,减小风电机组载荷,保证风电机组安全稳定运行.采用GH Bladed建模仿真,其仿真结果证明了控制策略的可行性和有效性.