减小风力机1P气动载荷和3P气动转矩脉动的独立变桨距控制策略研究

INDIVIDUAL PITCH CONTROL STRATEGY OF WIND TURBINE TO REDUCE 1P AERODYNAMIC LOAD AND 3P AERODYNAMIC TORQUE RIPPLES

为研究风切变和塔影效应对三叶片风力机气动载荷、气动转矩以及输出功率的影响，根据风切变和塔影效应的风速模型，引入等效风速模型，推导分析风力机1P（P为风轮旋转频率）气动载荷和3P气动转矩脉动的形成机理，并基于GH Bladed仿真平台验证这2种脉动的存在性。为减小这2种脉动对风力机产生的影响，基于变桨控制，设计带通滤波器过滤出风力机输出功率的3P脉动分量，并结合方位角信号将其转换为每支叶片的桨距角调节信号，与统一变桨控制的桨距角参考信号叠加，实现基于输出功率和方位角联合反馈的独立变桨距控制。仿真结果表明，所提独立变桨距控制策略不仅能有效缓解风力机1P叶根挥舞载荷脉动，还能明显减小气动转矩和输出功率的3P分量，从而在减小风轮疲劳载荷的同时提高风电机组输出电能质量。

In order to study the influence of wind shear and tower shadow on the aerodynamic load, torque and output power of three-bladed wind turbine, the equivalent wind speed model is introduced based on the wind model of wind shear and tower shadow, the formation mechanism of 1P aerodynamic load and 3P aerodynamic torque ripples is derived, and the existence of the two ripples is verified on GH Bladed platform. In order to reduce the influence of the two ripples on wind turbine, the individual pitch control based on combined output power and azimuth angle feedback is studied, by designing a band-pass filter to obtain the 3P component of output power, calculating the pitch angle adjustment signal of each blade according to azimuth angle, and superimposing with the pitch angle reference value of collective pitch control. Simulation results show that the proposed individual pitch control strategy can not only effectively alleviate the ripples of 1P load, but also significantly reduce the 3P component of the torque and output power. The proposed individual pitch control strategy has good potential in reducing the rotor fatigue loads and improving the output power quality of wind turbine.