基于混合滑模变结构的异步电机矢量控制系统研究

发布时间：2018-05-21 17:08

本文选题：异步电机 + 矢量控制　；参考：《河北工程大学》2014年硕士论文

【摘要】：异步电机具有可靠性高、制造成本低、维护方便等优点，在交流调速领域广泛应用。但异步电机是一个强耦合的时变系统，不能将励磁电流与转矩电流分开控制，这使得异步电机的数学模型在调速过程中存在偏差，在控制精度较高的场合，调速性能不能满足要求。异步电动机矢量控制可以解决交流控制系统中定转子磁链耦合问题，提高交流调速系统控制性能。但异步电动机矢量控制控制系统要获得良好的调速控制性能还需依赖于精确电机参数，在电机在运行过程中，，不可避免地会出现不确定性干扰以及由于温度升高等导致的电机参数的变化等问题，这些都将使调速控制系统控制性能下降。滑模变结构控制对系统数学模型要求不高，且对电机参数变化具有很好的鲁棒性。为了进一步增强系统的抗干扰能力，提高驱动系统的控制性能，本文将异步电机矢量控制系统的和改进滑模变结构控制策略结合进行了研究。本文首先对异步电机矢量控制原理进行了分析并在MATLAB/Simulink仿真软件中建立了异步电机矢量控制系统模型。其次本文第三章通过对大量文献以及控制系统仿真研究得出滑模变结构控制虽然对电机模型要求不高具有较好的鲁棒性但存在抖振。为了减小控制系统抖振问题，本文第四章建立了基于改进的滑模变结构控制的控制器。改进的滑模变结构控制器在常规滑模变结构控制器中增加了改进的切换项函数。切换项函数采用了改进的指数趋近律，该趋近律的趋近速度能很好的反应出系统当前状态与滑模面的距离，能根据状态量与滑模面之间的距离自动调节趋近速度。最后为了对改进的混合滑模变结构器性能进行研究，第五章利用MATLAB/Simulink仿真软件在异步电机矢量控制系统中分别建立了PI控制器，常规滑模变结构控制器以及改进的滑模变结构控制器模型。并对系统速度跟踪，正反转，增加负载等工况下系统控制性能进行了仿真。仿真结果表明改进的滑模变结构控制器能有效的加快系统跟踪速度，改善系统动态调速能力，增强系统鲁棒性。
[Abstract]:The asynchronous motor has the advantages of high reliability, low manufacturing cost and convenient maintenance, so it is widely used in the field of AC speed regulation. However, the induction motor is a time-varying system with strong coupling. The excitation current and torque current can not be controlled separately, which makes the mathematical model of the induction motor deviate in the course of speed regulation, and the control accuracy is high. Speed regulation performance can not meet the requirements. Vector control of asynchronous motor can solve the coupling problem of stator and rotor flux in AC control system and improve the control performance of AC speed regulating system. However, in order to obtain good speed control performance of asynchronous motor vector control system, it is necessary to rely on precise motor parameters. There will inevitably be some problems such as uncertainty disturbance and the change of motor parameters due to the increase of temperature. All of these will make the control performance of the speed control system degrade. Sliding mode variable structure control (VSC) requires not only the mathematical model of the system, but also has good robustness to the variation of motor parameters. In order to further enhance the anti-interference ability of the system and improve the control performance of the drive system, the vector control system of asynchronous motor and the improved sliding mode variable structure control strategy are studied in this paper. In this paper, the principle of vector control of asynchronous motor is analyzed, and the model of vector control system of asynchronous motor is established in MATLAB/Simulink simulation software. Secondly, the third chapter of this paper through a lot of literature and control system simulation research, it is concluded that the sliding mode variable structure control has good robustness to the motor model, but there exists buffeting. In order to reduce the buffeting problem of control systems, a controller based on improved sliding mode variable structure control is established in chapter 4. The improved sliding mode variable structure controller adds an improved switching term function to the conventional sliding mode variable structure controller. The switching term function adopts an improved exponential approach law. The approach speed of the law can well reflect the distance between the current state of the system and the sliding mode surface, and can automatically adjust the approach velocity according to the distance between the state quantity and the sliding mode surface. Finally, in order to study the performance of the improved hybrid sliding mode converter, in chapter 5, Pi controllers are established in the vector control system of asynchronous motor using MATLAB/Simulink simulation software. Conventional sliding mode variable structure controller and improved sliding mode variable structure controller model. The control performance of the system is simulated under the conditions of speed tracking, forward and reverse rotation and increasing load. The simulation results show that the improved sliding mode variable structure controller can effectively accelerate the tracking speed of the system, improve the dynamic speed of the system and enhance the robustness of the system.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM343

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