异步电机矢量控制系统的参数辨识研究

【作者】 张艳存；

【导师】 喻寿益；

【作者基本信息】 中南大学 ， 控制科学与工程， 2008， 硕士

【摘要】 本文主要研究异步电机矢量控制系统中的参数辨识问题。目前,矢量控制方法是交流调速领域较为成熟的控制方法,它基于转子磁场定向通过旋转坐标系变换,实现定子电流的解耦。矢量控制建立在转子磁链准确观测基础上,控制系统性能受电机参数变化影响较大。异步电机受工况影响,电机参数会发生变化,特别是转子电阻和电感随温度变化,导致转子磁链观测存在误差,影响定子电流完全解耦,从而降低矢量控制系统性能。论文简要介绍了异步电机矢量控制系统的组成以及工作原理,证明电机参数辨识的必要性;借助Matlab/Simulink软件工具定量分析了电机参数变化对转子磁链观测的影响,并定性分析了电机参数变化对矢量控制系统稳态、动态性能的影响,阐明电机参数辨识的重要性。为了抑制电机参数变化对矢量控制系统性能的不良影响,论文采用模型参考自适应法在线辨识异步电机转子时间常数。推导了基于转子磁链模型的转子时间常数辨识算法,但其辨识精度受定子电阻变化影响较大。因此采用基于无功功率模型的转子时间常数辨识算法,消除定子电阻变化对辨识算法的影响,并应用模糊控制技术改进自适应律,提高该辨识算法的收敛速度,得到基于模型参考模糊自适应的转子时间常数辨识方法。将这种参数辨识方法应用于异步电机矢量控制系统,并利用Matlab/Simulink软件进行仿真实验,仿真结果表明该参数辨识算法具有良好的准确性和理想的收敛速度,明显改善了异步电机矢量控制系统性能。更多还原

【Abstract】 This paper focuses on the parameters estimation of vector control system of asynchronous motor. At present, the vector control strategy works well in the field of alternating current speed regulation, which bases on rotor flux orientation and solves the decoupling problem of stator current through rotating coordinate system transform. Because the vector control based on the accurate observe of rotor flux, its performance is greatly affected by the change of motor parameters. However, asynchronous motor is influenced by working condition and its parameters change. Especially the resistance and inductance of rotor change as the temperature, resulting in the incensement of observing error of rotor flux and incomplete decoupling of stator current so as to reduce the performance of the vector control system.The components and working principle of vector control system of asynchronous motor is presented briefly to prove that it is necessary to identify motor parameters. And then the influence of parameters changing on observation accuracy of rotor flux is quantitatively analyzed by Matlab/Simulink and the influence on the dynamic and static performance of vector control system is also analyzed, so it is important to identify motor parameters.In order to restrain the blight of parameters changing on vector control system, model reference adaptive is used for rotor time constant of induction motor on-line estimation. The method of identifying rotor time constant based on rotor flux model is deduced but the change of stator resistance affects heavily on the identification accuracy. Therefore, the method of identifying rotor time constant based on reactive power model is used to reduce the influence of the change of stator resistance, and fuzzy control technology is used to improve adaptive law to increase convergence rate, and then the method of identifying rotor time constant based on model reference fuzzy adaptive is proposed. The method is applied in vector control system, and the simulation result in simulation experiment by Matlab/Simulink shows that the method of identifying rotor time constant has high accuracy and convergence rate, and it improves the performance of vector control system effectively.更多还原