参与电网调频的风电机组线性变参数变桨控制策略

Linear Parameter Varying-based Pitch Control Strategy for Wind Turbines Participating in Power Grid Frequency Regulation

风电机组参与调频时其输出功率的调整将改变风电机组变桨动作的风速范围,同时由于桨距角调节气动功率的灵敏度随风况变化,使得传统PI变桨控制难以适用于风电机组参与调频时的复杂工况,出现风电机组转速振荡问题。提出一种基于线性变参数(Linear Parameter Varying, LPV)系统的风电机组变桨控制方法,对风电机组模型进行线性化,根据风速和桨距角的变化范围进行凸分解,得到其具有四面体结构的LPV模型,通过求解不同平衡点处的线性矩阵不等式(Linear Matrix Inequality, LMI)设计出相应的变桨控制器。仿真结果表明:与传统PI变桨控制相比,LPV变桨控制能有效减小转速的波动,降低低速轴载荷以及减小桨距角的波动程度,验证了该控制策略的有效性和先进性。

When wind turbine participates in frequency regulation, the adjustment of output power will change the wind speed range in which pitch angle is needed to adjust.Additionally, the sensitivity of pitch angle to aerodynamic power varies with wind condition, which causes difficulty to apply the traditional PI pitch controller for complex conditions as wind turbine participates in frequency regulation, leading to rotor speed oscillation.Therefore, in this paper, a design method of wind turbine pitch controller is proposed based on linear variable parameter system(LPV).This method linearizes the wind turbine model, and the LPV model is obtained by convex decomposition according to the change range of wind speed and pitch angle, then the corresponding pitch controller is obtained by solving the linear matrix inequality(LMI).Compared with the traditional PI pitch controller, the LPV controller can effectively reduce the fluctuation of the rotational speed, reduce the low-speed shaft load and reduce the fluctuation of the pitch angle.The effectiveness and advancement of the method are verified by simulation.