【作者】 董长宏；

【导师】 王英；

【作者基本信息】 大连交通大学 ， 交通信息工程及控制， 2007， 硕士

【摘要】 直接转矩控制技术自问世以来，就以其新颖的控制思想、简洁明了的系统结构、优良的动态和静态性能受到了广泛的关注并得到了迅速的发展。但是在异步电动机低速运行区段时，应用直接转矩控制技术仍然存在一些缺陷。针对直接转矩控制技术在异步电动机低速运行区段，转矩、电流和磁链脉动较大和调速过程转矩动态响应时间过缓等缺点，本文采用近似圆形定子磁链轨迹的控制理论，通过含有P／N调节器的转矩调节器、三点式磁链调节器、新型定子磁链观测器等改进的控制模块，同时结合对电压空间矢量选择单元的改进，从而较好地降低了转矩、电流和磁链的脉动，改善了直接转矩控制系统的调速性能和转矩动态响应。本文主要完成的工作包括以下几个方面：根据异步电机直接转矩控制的基本原理建立了改进的直接转矩控制系统的数学模型；利用MATLAB／SIMULINK软件，通过软件编程和模块调用，完成了含有P／N调节器的转矩调节器、三点式磁链调节器和新型磁链观测器的仿真模型的设计，搭建了直接转矩控制系统低速性能改善的仿真模型平台。通过改变转速和额定负载转矩等控制参数，对系统进行了低速运行区段和调速过程的仿真，分析比较最终的仿真结果后表明，本文所提出的改善策略使得直接转矩控制技术在异步电动机低速运行区段的控制性能有了较好的改善，转矩、电流和磁链脉动均得到了有效的控制，系统转矩的动态响应性能良好。直接转矩控制中无速度传感器技术的应用一直是该领域的研究热点。本文同时还分析了基于异步电动机物理模型的直接计算法以及基于模型参考自适应系统(MRAS)的速度辨识方法，这将为在直接转矩控制系统实用性模型中，能够合理的设计出速度反馈环节提供必要的理论支持。更多还原

【Abstract】 After direct torque control technology was invented, it has been given wide concern and has got rapid development because of its original control notion, concise system structure and excellent capability on activity and immobility. On the other hand, DTC technology directly applies optimum control on the switch conditions of inverter and generates.In this paper, summary to the question that in the DTC the ripples of torque,current and flux are large,switching frequency is low and not fixed, we develop the following improving method: the application of the integrated torque regulation be composed of P/N regulation; the application of flux regulation at three levels, use of improved swithching tables; use of the new stator flux observer based on the low-pass filter is designed. Use of this method can not only improve performance of motor through decreasing the ripple of torque, flux and current but also improve capability on activity.At first this thesis introduces the basic principle of direct torque control on asynchronous motor. Through mathematics model of asynchronous motor stator flux and torque can be got. The model of simulink is designed. The keystone of this thesis is the solving project for improving low-speed section of Asynchronous Motor based DTC. The thesis point out the following project: To demonstrate the validity of the asynchronous motor’s direct torque control system, simulation system of DTC is designed through the simulation software MATLAB/SIMULINK. The result of the test is analyzed. On the other hand, after changing the parameters in direct connection with flux- regulation and torque-regulation, this paper gives the effect of changing parameters to motor ability. The result of simulation expresses, this paper’s standpoint is a good project for improving low-speed section of the asynchronous motor.The speed sensorless estimation is an important trend of modern AC drive. This paper has discussed several primary algorithm of speed estimation and emphasized on the algorithm of speed estimate based on model reference adaptive system. It will become the theoretics support during designing the speed-recive part of the really DTC.更多还原