减小桨叶载荷的风电独立变桨优化控制模型

Model of Individual Blade Pitch Control of Wind Turbine to Reduce Load

针对超额定风速下运行的变速变桨风电机组,研究在维持功率额定的条件下,如何减小风剪切效应所引起的不平衡载荷,从而延长风机寿命。首先依据空气动力学原理,以不平衡载荷最小为优化目标,保证输出功率与额定功率的偏差在一定范围内为约束条件,建立载荷优化模型;然后采用非线性最小二乘法,以统一变桨距角为初值,优化计算得到3个桨叶对应的最优桨距角,以该角度为参考值分别进行独立变桨距控制。仿真结果表明,与传统变桨距控制方法相比,所提模型在保证功率维持在额定值附近的前提下,大幅度减少了不平衡载荷,且避免了频繁变桨。

This paper presents an optimal individual pitch control method for wind turbines operating at high wind speeds to reduce the unbalanced load caused by wind shear while maintaining the rated power, thus prolong the life of wind turbine. According to the principle of aerodynamics, a model of load optimization is established with the minimiza- tion of unbalanced load as objective, and restricting the difference between output power and rated power within allow- able range as restraint. Using the nonlinear least square method and with the unified individual pitch angles are initial values, the optimal pitch angles corresponding to three blades are calculated, and these angles are further used as refer- ence values to realize individual pitch control, respectively. Simulation results indicate that compared with the tradition- al pitch control method, the proposed model can reduce the unbalanced load significantly and avoid the loss of power and the frequent pitching.