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大型双馈风电机组动态载荷控制策略研究

Research on Dynamic Load Control Strategy of Large Scale Double Feed Wind Turbine

【作者】 王晓东

【导师】 姚兴佳;

【作者基本信息】 沈阳工业大学 , 电工理论与新技术, 2011, 博士

【摘要】 随着风力发电技术和产业的迅速发展,风电机组单机容量不断增大,叶片、传动系统和塔架等主要部件的柔性显著增加,机组运行过程中所受的动态载荷越来越复杂。通过控制策略减小风电机组动态载荷已成为风力发电领域的一个研究热点。本文以国家科技支撑计划重大专项“适应海、陆环境的双馈式变速恒频风电机组的研制”课题为依托,以3MW双馈变速恒频风电机组为对象,对动态载荷控制策略进行了深入的研究。目的是通过叶片桨距角和发电机转矩控制减小机组运行过程中所受的动态载荷,重点解决风电机组无法准确建模、强外部扰动给动态载荷控制带来的问题。主要研究工作归纳如下:基于对风电机组运行过程中所受动态载荷及其特性的研究分析,提出了一种双环结构风电机组动态载荷控制策略。为了在确保发电量的前提下,通过控制策略减小风电机组运行过程中的动态载荷,在发电机转矩控制和变桨距控制的基础上分别叠加了动态载荷控制环,以变桨距系统、变流器为作动器通过减小叶片受力不平衡和抑制振动减小风轮、塔架和传动系统的动态载荷。研究了以变桨距系统为作动器的风轮不平衡载荷和塔架顶部载荷主动控制方法。针对风速空间分布、风速变化及风轮流固耦合无法准确建模的问题,提出了基于泛模型的风轮动态载荷自适应控制策略。该方法不依赖于风轮的精准数学模型,且能较好的解决三个叶片桨距角和风轮动态载荷的非线性耦合、载荷测量引起的时滞等问题。仿真结果表明,基于泛模型的风轮动态载荷自适应控制能明显减小风轮不平衡载荷、抑制风轮和塔架的耦合振动,减小塔架顶部载荷。研究了以变流器为作动器的传动系统扭转载荷主动控制方法。针对齿轮弹性形变、齿轮啮合误差、柔性联轴器弹性形变等不确定因素导致的参数动态变化问题,建立了考虑不确定因素作用的传动系统集中参数模型,并以此为基础提出了传动系统扭转载荷自抗扰控制策略。采用扩张状态观测器将传动系统内部不确定因素作用和外部扰动归结为总扰动进行动态估计,并在状态误差反馈中进行补偿,提高了控制器对系统内部不确定因素和外部干扰的鲁棒性。仿真结果表明,传动系统扭转载荷自抗扰控制策略能够明显抑制传动系统扭矩波动,减小扭转载荷。对动态载荷控制策略进行了试验验证。构建了3Mw风电机组控制系统半实物测试平台,通过模拟典型风电场风况对动态载荷控制策略进行了试验研究。试验结果进一步验证了本文所应用的控制算法和提出的动态载荷控制策略在减小风电机组动态载荷方面是可行且有效的。

【Abstract】 With the rapid development of wind energy technology and industry, the capacity size of wind turbine become more and more bigger, the rotor, drive train and tower become more and more flexible, which lead to the wind turbine dynamic load go into complexity and inclemency. The 3MW double feed wind turbine is taken as the research object in this thesis based on the project supported by National Key Technology Research and Development program. The goal of the research work is to reduce the dynamic load through special control strategy design, and the key is to solve the problem from the difficulty in building the rotor aero model and disturbance effect. Following is the main contents of this thesis:A kind of double loop control strategy is put forward based on analyses of wind turbine dynamic load and its influencing factor. In order to reduce the dynamic load on the premise of ensuring the output energy, the dynamic load active control loop is leaded into the power and speed controller, in which the pitch system and the inverter is taken as actor.The active control method of rotor unbalance aerodynamic load and tower top load is studied. Aimed at the complex noline coupling and the difficulty in building the mathematic aero model of rotor, a kind of rotor dynamic load active control strategy based on general model. It is a model free method. and it is good at handled the noline coupling of three pitch angle and rotor dynamic load and the sensor delay. The GH bladed simulation result shows that the dynamic load active control strategy based on general model can reduce the rotor unbalance load, restrain the coupling vibration between rotor and tower, and reduce the tower top load.The active control method of drive train rotation dynamic load is studied. Aimed at the parameter perturbation problem from the uncertainty factor, such as gear elastic deformation, gear engaging error, dynamic stiffness and damp of flexible coupling, the drive train dynamic model including uncertainty factor effect is built. An active disturbance rejection rotation dynamic load active control strategy is put forward. The strategy reduces the load through torque vibration surprising based on extended status observer and nonlinear state error feedback. The uncertainty factor effect and external disturbance are summarized as general disturbance. The general disturbance is estimated by extended status observer and compensated in nonlinear state error feedback. The GH bladed simulation result shows that the active disturbance rejection load active control strategy can surprises the drive train torque vibration and reduce the rotation dynamic load.The dynamic load active control strategy is verified through measurement on a wind turbine control system test bench. A 3MW wind turbine control system test bench is built. The strategy is tested through simulate the wind of classic wind farm. The test data shows that the new presented control strategy is feasible and effective.

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