异步电机弱磁控制系统的设计

发布时间：2018-08-23 11:55

【摘要】：高速数控机床是先进制造技术的核心，其性能主要取决于高速主轴的性能，目前我国高速化驱动技术与国外先进水平相比仍有一定差距。异步电机的结构适合于弱磁高速运行，一直是主轴驱动电机的主流，因而研究其弱磁控制技术具有一定的现实意义。按转子磁场定向的矢量控制方案，可实现电机转矩电流和磁场电流的解耦控制，是进行异步电机弱磁控制的基础。本文首先从电机空间矢量定义入手，推导出异步电机的动态方程，然后在此基础上详细阐述了转子磁场定向和间接矢量控制原理。在交流电机矢量控制中，，常采用空间矢量脉宽调制（SVPWM）方法生成逆变器驱动脉冲信号。本文介绍了SVPWM的基本原理及其实现步骤，并引入了一种基于傅立叶分解的线性增益过调制策略，在减小电压畸变的同时实现了近似于1的调制比。异步电机运行过程中会受到最大电压、电流和最大转差率的限制，本文根据这些约束条件推导出了异步电机转矩最大化电流矢量轨迹，并在此基础上引出了基于电机理想模型的基本弱磁策略。针对基本弱磁策略的不足，一种加入了电压反馈的改进弱磁策略被提出。此外，本文构造了复矢量PI控制器解决高速运行控制量耦合加剧的问题，并设计了一种基于无功的转子时间常数在线辨识算法，以削弱转子时间常数变化对磁场定向的影响。最后，本文搭建了基于matlab的异步电机弱磁控制系统仿真平台，对文章各部分算法的有效性进行了验证。
[Abstract]:High-speed CNC machine tool is the core of advanced manufacturing technology, and its performance mainly depends on the performance of high-speed spindle. At present, there is still a certain gap between high-speed drive technology of our country and advanced level of foreign countries. The structure of asynchronous motor is suitable for high speed operation of weak magnetic field and has always been the mainstream of spindle drive motor. Therefore, it is of practical significance to study the weak magnetic field control technology of asynchronous motor. The decoupling control of torque current and magnetic field current can be realized according to the vector control scheme of rotor flux orientation, which is the basis of the weak magnetic field control of asynchronous motor. In this paper, the dynamic equation of induction motor is derived from the definition of space vector, and then the principle of rotor flux orientation and indirect vector control is described in detail. In vector control of AC motor, space vector pulse width modulation (SVPWM) method is often used to generate inverter driving pulse signal. This paper introduces the basic principle of SVPWM and its implementation steps, and introduces a linear gain overmodulation strategy based on Fourier decomposition, which can reduce the voltage distortion and achieve a modulation ratio of approximately 1. The maximum voltage, current and maximum slip rate of the asynchronous motor will be limited during operation. According to these constraints, the maximum current vector locus of the torque of the asynchronous motor is derived in this paper. On this basis, the basic weak magnetic field strategy based on the motor ideal model is introduced. In order to overcome the shortcomings of the basic weak magnetic strategy, an improved weak magnetic strategy with voltage feedback is proposed. In addition, a complex vector Pi controller is constructed to solve the problem of increasing coupling of high speed control variables, and an on-line reactive power based rotor time constant identification algorithm is designed to weaken the influence of rotor time constant change on magnetic field orientation. Finally, the simulation platform of induction motor weak magnetic field control system based on matlab is built, and the validity of each part of the algorithm is verified.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM343;TM301.2

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