基于模糊控制的双馈式风力发电机并网研究

发布时间：2018-04-02 23:05

本文选题：风电并网　切入点：双闭环　出处：《东北石油大学》2016年硕士论文

【摘要】：由于风能的间歇性等因素,使得双馈式异步风力发电系统具有时变性、多变量性、非线性等,并网运行期间无法精确测量每台电机的参数。从而增加了控制难度,影响并网过程。在并网电压幅值控制中,传统的PI控制方法需要模型参数,所以在参数变化时控制效果不佳。虽然模糊控制不需要精确的数学模型,鲁棒性强,但是其控制点附近误差大,存在盲区和死区,控制精度差。通过对发电机数学模型的分析,本文将模糊控制与PI控制相结合,应用于网侧变换器控制中,外环采用直流电压PI控制,保证网侧变换器的正常工作和励磁电流的正弦波形,从而控制输入功率因数。内环采用模糊PI控制,以转子电流PI控制为主,结合电网电压模糊控制为辅,构造模糊PI控制器,控制并网时的电压幅值,分别在理想情况下和电机参数发生变换的情况下对该控制方法进行验证分析,对比传统的电流模糊PI控制。该系统可以很好的控制定子电压幅值,响应速度快精度高,对发电机参数的变化具有很好的鲁棒性。在风机功率控制方面,本文在传统的扰动观察法的基础上改进,采用模糊扰动观测法,主要思想为在风机的功率曲线上取不同的观测点,依据每个观测点斜率,通过模糊控制来调节扰动观测的步长,当斜率较大时采用大步长追踪实现粗调,当斜率较小时采用小步长追踪实现细调节。实现风机最大功率追踪控制。该方法不但可以提高风机功率调节速度,还可以提高精度。
[Abstract]:Because of the intermittent wind energy, the doubly-fed asynchronous wind power generation system is time-varying, multi-variable, nonlinear and so on. It is impossible to accurately measure the parameters of each motor during grid connection.Thus, it increases the difficulty of control and affects the process of grid connection.In grid-connected voltage amplitude control, the traditional Pi control method needs model parameters, so the control effect is not good when the parameters change.Although fuzzy control does not need accurate mathematical model, it has strong robustness, but the error near control point is large, there are blind area and dead zone, and the control precision is poor.By analyzing the mathematical model of generator, this paper combines fuzzy control with Pi control, and applies it to the control of grid-side converter. The outer loop adopts DC voltage Pi control to ensure the normal operation of grid-side converter and the sine wave shape of excitation current.Thus the input power factor is controlled.The inner loop adopts fuzzy Pi control, with the rotor current Pi control as the main control, combined with the grid voltage fuzzy control as the auxiliary, the fuzzy Pi controller is constructed to control the voltage amplitude when connected to the grid.The proposed control method is verified and analyzed under ideal conditions and in the case of motor parameter transformation, and compared with the traditional current fuzzy Pi control.The system can control the voltage amplitude of the stator well, the response speed is fast and the precision is high, and the system is robust to the change of generator parameters.In the aspect of fan power control, this paper improves on the traditional disturbance observation method and adopts the fuzzy disturbance observation method. The main idea is to take different observation points on the power curve of the fan, according to the slope of each observation point.The step size of disturbance observation is adjusted by fuzzy control. When the slope is large, the coarse tuning is realized by using large step tracking, and the fine adjustment is realized by small step tracking when slope is small.The maximum power tracking control of fan is realized.This method can not only improve the speed of fan power regulation, but also improve the accuracy.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM315

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