基于动力学耦合的风电机组载荷控制

发布时间：2018-07-24 13:08

【摘要】：风电机组日趋大型化,结构柔性增加,风轮载荷的低频波动,极易引发传动链、塔架、叶片的振动。针对风电机组载荷控制问题,主要研究工作:1、研究了复杂风况下风轮载荷特性根据风切变的指数模型分析了风切变指数、风轮直径对风轮载荷的影响。使用上风向塔影效应模型,分析塔筒对风速分布的影响。基于Kaimal谱建立了风湍流模型,分析湍流对风轮面上风速分布的影响。结果表明,风切变、塔影效应是风电机组中载荷周期性变化的主导因素,风湍流、尾流效应致使风轮多叶片载荷出现不对称。风轮载荷波动传递到机组其它部件成为周期性的激励力,当激励频率与其它部件固有频率一致时可产生大幅度的共振。2、建立了基于动力学的风电机组载荷模型基于叶素动量理论建立了风轮静态载荷模型,针对叶素动量理论的不足,研究了叶尖轮毂损失修正、诱导因子修正、动态入流修正、动态失速修正,使风轮载荷模型适用于动态载荷计算。依据材料力学推导了叶片、塔架的模态计算方法,研究了叶片、塔架的模态,通过模态叠加法构建了风轮、塔架的结构动力学模型。根据传动链、变桨系统、电机系统的主要动态特性建模。提出使用离散数值计算方法实现风电机组的载荷计算。3、提出了基于LPV增益调度的风电机组功率控制方法研究了复杂风况下风电机组风轮转速特性,将风轮惯性、状态估计风速引入变桨控制中,增强了风电机组控制系统应对风速变化的能力,稳定了机组的功率输出。风电机组是一个非线性的矢量系统,系统的稳态轨迹是一条空间曲线,提出使用LPV增益调度方法控制风电机组的功率,LPV增益调度控制将风电机组运行轨迹稳定在运行域内,增强了风电机组功率输出的稳定性。4、研究了可降低传动链、塔架、叶片疲劳载荷的风电机组载荷控制策略研究了传动链的扭振特性,使用Kalman滤波估计传动链的状态,通过发电机转矩控制,在传动链中增加阻尼控制,抑制了传动链的扭振,减缓齿轮的疲劳载荷,延长其疲劳寿命。研究了塔架的摆振特性,塔架在前后向存在气动阻尼作用,塔架在侧向阻尼很小极易发生大幅度振动,在变桨控制和发电机转矩控制中增加塔架阻尼控制,降低了塔架摆动幅度,增强了机组运行的可靠性。研究了复杂风况下叶片载荷波动的特性,提出了独立变桨控制降低叶片疲劳载荷。独立变桨控制把三个叶片的载荷看成周期性对称的,通过dq坐标变换,实现叶片载荷中谐波分量的提取,应用增益调度的PI控制,降低了叶片载荷的波动。研究了风轮不对称载荷问题,将对称分量法用于独立变桨控制,把不对称风轮系统看作由正序、负序、零序3个子系统组合而成。在正序、负序子系统中使用独立变桨控制,有效的抑制了风轮不对称载荷。研究了基于三种载荷测量量的独立变桨控制,分别为叶片坐标系下的载荷,轮毂坐标系下的载荷,机舱坐标系下的载荷,提高了独立变桨控制系统的可靠性。
[Abstract]:The wind turbine is becoming more and more large, the structure flexibility increases, the low frequency fluctuation of the wind wheel load is very easy to trigger the transmission chain, the tower frame and the vibration of the blade. The main research work is on the load control problem of the wind turbine. 1. The wind wheel load characteristics are analyzed according to the wind shear index model and the wind wheel diameter to the wind wheel load under the complex wind condition. The influence of the upper air flow to the tower shadow effect model is used to analyze the influence of the tower tube on the wind velocity distribution. Based on the Kaimal spectrum, the wind turbulence model is established to analyze the influence of turbulence on the wind velocity distribution on the wind wheel surface. The results show that the wind shear is the dominant factor of the periodic variation of the load in the wind turbine, wind turbulence and the wake effect cause the wind wheel. The load fluctuation of the multi blade is asymmetrical. The load fluctuation of the wind wheel is transmitted to the other components of the unit as the periodic excitation force. When the excitation frequency is consistent with the natural frequencies of other components, a large amplitude resonance.2 can be produced. A dynamic load model of the wind turbine is set up based on the Ye Sudong theory to establish the static load model of the wind wheel. For the deficiency of the leaf prime momentum theory, the loss correction, the inducer correction, the dynamic inflow correction, the dynamic stall correction, which make the wind wheel load model applicable to the dynamic load calculation, are studied. The modal calculation method of the blade and the tower is derived according to the material mechanics, the modal of the blade and the tower is studied, and the wind is constructed by the modal superposition method. The dynamic model of the structure of the tower is modeled. According to the main dynamic characteristics of the transmission chain, the variable propeller system and the motor system, the load calculation of the wind turbine is realized by using the discrete numerical calculation method (.3). The power control method of the wind turbine based on the LPV gain scheduling is proposed to study the speed characteristics of the wind turbine in the complex wind turbine. The wind turbine inertia and the state estimation wind speed are introduced into the variable propeller control, which enhances the ability of the wind turbine control system to respond to the change of wind speed and stabilizes the power output of the unit. The wind turbine is a nonlinear vector system, the steady-state trajectory of the system is a spatial curve, and the LPV gain scheduling method is proposed to control the power of the wind turbine, LPV The operation trajectory of the wind turbine is stable in the operating domain, and the stability of the power output of the wind turbine is enhanced by.4. The load control strategy of the wind turbine which can reduce the transmission chain, the tower and the fatigue load of the blade is studied. The torsional vibration characteristics of the transmission chain are studied. The state of the transmission chain is estimated with the Kalman filter, and the torque of the generator is used to pass the generator torque. Control, adding damping control in the transmission chain, restraining the torsional vibration of the transmission chain, slowing down the fatigue load of the gear and prolonging its fatigue life. The vibration characteristics of the tower are studied. The tower frame has the aerodynamic damping effect in the front and back, and the tower is very easy to have large amplitude vibration in the lateral damping, and the tower is added to the variable paddle control and the generator torque control. The frame damping control reduces the swing amplitude of the tower and enhances the reliability of the operation of the unit. The characteristics of the blade load fluctuation in the complex wind condition are studied. The independent variable propeller control is proposed to reduce the blade fatigue load. The independent variable propeller control takes the load of the three blades as periodic symmetry, and the load harmonic in the blade is realized through the transformation of the DQ coordinates. Using the PI control of the gain scheduling to reduce the fluctuation of the blade load, the asymmetric load problem of the wind turbine is studied. The symmetric component method is applied to the independent variable propeller control, and the asymmetrical wind wheel system is composed of 3 subsystems, positive sequence, negative sequence and zero sequence. The independent variable propeller control is used in the positive sequence and negative sequence subsystems. The unsymmetrical load of the wind wheel is suppressed. The independent variable propeller control based on three kinds of load measurement is studied. The load under the coordinate system of the blade, the load in the hub coordinate system and the load in the cabin coordinate system can improve the reliability of the independent variable propeller control system.
【学位授予单位】：华北电力大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM315

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