风电机组风轮不平衡载荷的影响分析与控制

发布时间：2018-07-21 08:45

【摘要】：随着新能源技术的发展,风能在电力能源结构中所占比例不断增加。中国风电机组装机总容量已达到全球第一,单机容量更大,塔架更高,叶片更长,是当代风电技术发展的主要趋势。不平衡载荷引发的风电机组振动及转矩波动问题愈发严重,影响着风电机组的运行安全。一旦过振失控,轻则过疲劳损伤,重则塔架断裂倒塌。因此,对风电机组的载荷、塔架位移的控制研究意义重大。为研究不平衡载荷对风电机组气动转矩的影响,在空气动力学的理论基础上,建立了将风切变、塔影效应考虑在内的风模型,利用对该模型求解得到的等效风速可直接用于计算气动转矩。仿真结果表明了风切变、塔影效应的存在使得气动转矩产生3p的波动,并通过仿真结果对比得知,塔影效应对输出转矩的影响远大于风切变的影响。同时,气动转矩的波动会造成塔架的振动,利用结构动力学的知识,对叶片与塔筒的各阶振型进行仿真建模,并对其振动频率进行了分析,为后续的控制环节设计提供理论依据。风电机组的变桨调节主要用于额定风速以上的恒功率控制及额定风速以下的风能捕捉优化。同步变桨控制能够在风速高于额定风速时维持风电机组的额定功率输出,但是无法实现对不平衡载荷的控制,因此,所设计的整个变桨距控制系统包含两部分内容,一部分为同步变桨控制用于保持风电机组的额定功率,另一部分是在同步变桨基础上针对载荷的独立变桨距调节。根据风电机组设计的基本理论,建立风电机组模型,提出基于增益调度算法的同步变桨控制,并在经典运动方程中引入独立变桨距载荷控制算法,依据鲁棒控制与最优控制理论,完成控制器的设计。在MATLAB完成控制器的仿真,并利用C++语言编写dll文件完成GL Bladed软件外部控制器的编写,实现了同步变桨算法与独立变桨算法的控制过程,结果表明所采用的控制方法能够在满足风电机组变桨距控制需求的基础上,显著减小不平衡载荷和塔架俯仰力矩。
[Abstract]:With the development of new energy technology, the proportion of wind energy in power energy structure is increasing. The total installed capacity of wind turbine units in China has reached the first place in the world, the single unit capacity is larger, the tower is higher, and the blade is longer, which is the main trend of the development of modern wind power technology. The problem of wind turbine vibration and torque fluctuation caused by unbalanced load is becoming more and more serious, which affects the safety of wind turbine operation. Once the vibration is out of control, the fatigue damage is light and the tower collapses. Therefore, it is of great significance to study the load and tower displacement control of wind turbine. In order to study the effect of unbalanced load on the aerodynamic torque of wind turbine, a wind model which takes wind shear and tower shadow effect into account is established on the basis of aerodynamics theory. The equivalent wind speed obtained from the model can be directly used to calculate the aerodynamic torque. The simulation results show that the wind shear and the tower shadow effect make the aerodynamic torque fluctuate with 3p. The comparison of the simulation results shows that the influence of the tower shadow effect on the output torque is much greater than the wind shear effect. At the same time, the vibration of the tower will be caused by the fluctuation of the aerodynamic torque. Using the knowledge of structural dynamics, the vibration frequency of the blade and the tower tube is simulated and modeled, and its vibration frequency is analyzed. It provides a theoretical basis for the subsequent design of control links. The variable propeller regulation of wind turbine is mainly used to control the constant power above the rated wind speed and to capture and optimize the wind energy below the rated wind speed. The synchronous propeller control can maintain the rated power output of the wind turbine when the wind speed is higher than the rated wind speed, but it can not realize the control of the unbalanced load. Therefore, the whole variable pitch control system is composed of two parts. One part is used to maintain the rated power of the wind turbine, the other is the independent pitch adjustment for load on the basis of synchronous variable propeller. According to the basic theory of wind turbine design, the wind turbine model is established, and the synchronous variable propeller control based on gain scheduling algorithm is proposed, and the independent variable pitch load control algorithm is introduced into the classical motion equation. According to the theory of robust control and optimal control, the controller is designed. The simulation of the controller is completed in MATLAB, and the external controller of GL laded software is compiled with C language dll file. The control process of synchronous pitch algorithm and independent pitch algorithm is realized. The results show that the proposed control method can significantly reduce the unbalanced load and the pitch moment of the tower on the basis of satisfying the requirements of variable pitch control of wind turbine.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614

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