【作者】 张伟；

【导师】 欧阳斌林；

【作者基本信息】 东北农业大学 ， 农业电气化与自动化， 2008， 硕士

【摘要】 传统的调速控制多采用直流电动机,这是由于直流电动机可以通过改变电枢电压以及调节励磁电流实现无级调速。但是直流电机存在结构复杂,造价昂贵,机械换向器与电刷之间存在换向火花等问题,而且维护困难。随着生产技术的发展,交流调速已经进入逐渐取代直流调速的时代。交流电动机是多变量,强耦合的非线性时变系统,与直流电动机相比,交流电机的转矩控制要困难的多。直接转矩控制(Direct Torque Control)理论很好的解决了这一问题。这一理论主要采用空间矢量的方法,直接在定子坐标系下计算和控制交流电机的磁链和转矩,采用定子磁场定向控制的方法,直接跟踪定子磁链和电磁转矩,借助于调节器产生的PWM信号,对逆变器的开关状态进行最佳控制,以获得高动态性能的转矩响应。本文利用MATLAB/Simulink工具箱中的电力系统模块,根据直接转矩控制原理,建立了调速系统的数学模型,进行了仿真研究,研究结果表明磁链轨迹近似为圆形,实际转速跟随指令转速效果良好。硬件方面主电路采用交-直-交的拓扑结构。在设计方面采用TI公司专门为电机驱动开发的DSP芯片TMS320LF2407A作为控制系统的处理器,该芯片集成了许多电机控制所需要的功能控制模块,减少了外围电路设计工作。驱动部分主要采用IPM为驱动核心,通过光电耦合电路和DSP通信。软件进行了整体方案的构建,给出了软件流程。最后,完成了包括启动及闭环运行等在内的仿真实验,分析了实验结果,总结了系统设计的成功和不足之处,并展望了直接转矩控制技术的发展前景。更多还原

【Abstract】 It is always used for speed control by direct current motor, because the direct current motor may realizes the stepless speed regulation by changing armature voltage as well as adjusting the exciting current.But the direct current motor is sure of a lot of problems such as that the structure is complicated, it is very expensive,at times it has commutator spark consist in mechanical commutator and electronics brush, and most of important is very difficult to repair direct current motor. Along with the production technology’s development, the time is coming that the exchange velocity modulation technology substitutes for the direct-current velocity modulation technology gradually.Asynchronous motor is multivariable,close coupling and non-linear system that is variational with the time going.The theory of direct torque control is soluting the problem very well.The flux and torque of stator of AC induction electromotor are calculated and controlled in the stator-oriented coordinates, are adopted stator magnetic field orientation, are directly tracked.The signal of PWM is builtby dint of the discrete adjustment in order to control optimally the state of the switches ofinverter and get the high dynamic performance torque response.In the environment of Matlab/Simulink, the paper uses the power system block to build a mathematic mode based on the principle of DTC system and has done some simulation. The result of the simulation proves that the trajectory of the magnetic link is almost circular, the rotor speed follows the given speed.The hardware circuit of the system adopts the AC-DC-AC topological structure. The system uses TMS320LF2407A DSP chip which is specialized in motor control system by Texan instrument company.The chip contains many special modules for motor control and decreases many peripheral instruments. The newest Intelligent Power Module is used for power instrument core, it is correspond to DSP by electric coupling electric circuit. I give the whole software design.Finally, this paper completes the simulation debugging of the open loop start and the closed loop motion,we have analyzed the experimental result, summarized design success and the insufficiency in this system and at last forecast the direct torque control present’s development.更多还原