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异步电机直接转矩控制系统的探讨与实践

Research and Practice of Direct Torque Control System of AC Induction Motor

【作者】 雷娟

【导师】 李春茂; 肖建;

【作者基本信息】 西南交通大学 , 系统工程, 2003, 硕士

【摘要】 近20年来,异步电动机直接转矩控制以其简洁明了的系统结构,优良的静、动态性能,得到了极大的发展。它直接在定子坐标系下计算和控制交流电动机的转矩,采用定子磁场定向控制,直接对逆变器的开关状态进行最佳控制。本文对直接转矩控制算法进行了仿真实验,并利用DSP实现控制系统的全数字化软件设计。 本文对异步电机直接转矩控制变频调速方法进行了研究,采用MATHWORKS软件公司为MATLAB开发的系统模型图形输入和仿真工具Simulink对直接转矩控制的六边形和近似圆形两种定子磁链控制方法进行了仿真,实现了有速度传感器的直接转矩控制系统的构建,从理论上证明了这两种方法的可行性。在仿真中分析了转矩滞环和磁链滞环参数的变化对系统控制性能的影响,并且对两种控制方法在基速范围内的切换进行了仿真研究,同时在仿真中采用积分分离式PI调节算法对传统的PI调节器进行了改进。 以TI公司生产的电机专用数字信号处理器TMS320F240为核心,可方便的实现直接转矩控制系统的全数字化。F240内部的外设模块为电机控制提供的硬件功能,使软件编程的工作得到大大的简化,它的实时运算能力大大提高了电机的控制性能和可靠性。在本文中采用DSP汇编语言完成了有速度传感器的直接转矩控制系统的软件编写,实现了定子相电流采样、相电压的计算、定子磁链的观测、开关信号输出等功能。 通过理论分析和对控制系统的设计,作者在DSP电机控制教学实验及系统开发平台上对六边形磁链控制算法进行了初步的开环实验,完成了电机在一定频率下空载和带负载的实验,并对实验结果进行了对比分析,结果验证了系统设计方案的可行性。

【Abstract】 During the recent 20 years, Direct Torque Control (DTC) for induction motor has been developed greatly because of its simple system scheme and excellent dynamic and static performances. In this scheme, the torque of motor is calculated and controlled in the staler reference frame. By using stator field orientation, the optimum switching mode is achieved to control the inverter. In this dissertation, the author has accomplished the simulation of the DTC system and analyzed the corresponding results. The software of the digital control system, in which the digital signal processor (DSP) is used, has also been designed in the thesis.The Direct Torque Control scheme is studied in the paper, and the simulation models of hexagon flux control system and approximate circle flux control system are presented based on the application of MATLAB/Simulink. In the simulation system, the performances have been analyzed when the parameter of torque hysterelic comparator or the hysteretic band of stator flux is changed. The simulat ion of switching between hexagon flux control and circle flux control is also compl eted. In addition, the traditional PI regulator is improved in the paper.The digital DTC system is implemented easily using TMS320F210, which is a fixed-point DSP and developed specially for motor&motion control by Texas Instruments Inc. It combines high-performance processing capabilities and several advanced peripherals that include the event manager module and a dual 10-bit analog-to-digital converter. The design of the control software becomes easy and the performance and reliability of the control system are greatly improved due to the application of DSP. In the thesis, the software of control system withspeed sensor is complied in DSP assembly language. This software has realized functions of the sampling of stator phase current, calculating of the phase voltage, the observing of stator flux and the output of switching signal etc.According to the analysis of the theory of DTC scheme and the design of the control software, the author of this paper has done the primary experiments of the open-loop hexagon flux control system using the DSP test-bed for experimentation and development of motor control. The experiments of motor without and with load on a given frequency are completed in this paper. These results are compared and analyzed. The feasibility of the scheme is validated through the analysis of the results.

  • 【分类号】TM343
  • 【被引频次】8
  • 【下载频次】576
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