随着国内外电力电子器件和电机控制芯片的不断更新换代，异步电动机的调速技术在不断发展，调速技术经历了调压调频控制、矢量控制和直接转矩控制等三个阶段。直接转矩控制作为一种新型的交流调速技术，其控制思想新颖、控制结构简单、控制手段直接以及转矩响应迅速等特点，使其在运动控制领域中发挥着越来越重要的作用。 直接转矩是通过控制电压空间矢量来控制磁链轨迹的旋转速度，达到控制电动机转速的目的。它是在定子坐标系下，利用磁链调节器和转矩调节器，直接跟踪定子磁链和转矩，从而控制逆变器输出的电压，以获得较快的转矩响应。 本文在阐述异步电动机定子坐标系的数学模型的基础上，介绍基于电压空间矢量的逆变器模型、六边形磁链轨迹的形成以及直接转矩的控制原理。分析电压空间矢量在磁链调节和转矩调节中的作用，研究磁链调节器的给定值与六边形磁链轨迹的关系、转矩调节器的容差值与输出转矩的关系以及占空比的大小与转速的关系。基于磁链调节原理，改变不同电压空间矢量的作用时间产生圆形磁链轨迹。 依据磁链和转矩的调节原理，就磁链给定值、转矩容差值和占空比在直接转矩中如何改变磁链轨迹、转矩脉动和转速的问题。在MATLAB／Simulink仿真平台下搭建开环直接转矩仿真模型，并建立仿真系统的各个模块。仿真研究表明磁链给定值越大，磁链轨迹越大；转矩容差值越大，输出转矩脉动越大；非零电压矢量的占空比越大转速越高。 设计直接转矩调速系统的软硬件系统，完成部分实验调试。硬件设计包括主电路和控制电路。主电路包括整流电路、启动电路、滤波电路、逆变电路，介绍逆变模块IPM的应用以及对各个器件的参数进行设计。控制电路包括DSP(TMS320F28335)控制芯片、隔离电路、故障信号电路、检测电路。介绍软件系统的开发环境CCS3.3，分析主程序和初始化程序流程图。对调速系统进行部分调试。

With the development of power electronics and motor control chips, the speed control technology of the asynchronous motor is developing rapidly which has gone through V/F control, vector control and direct torque control. Direct Torque Control is a new technology in the ares of AC speed control which has many advantages such as new control method, simple structure, direct control means and fast torque response. DTC technology is playing a very important role in the area of motion control. By controlling the voltage space vector, Direct Torque Control can control the rotation speed of flux, so as to achieve the goal of control motor speed. With the flux regulator and the torque regulator, DTC can follow the stator flux and the torque so as to control the output voltage and obtain fast torque response. In this thesis, Based on the mathematical model of asynchronous motor under the stator coordinate system. The inverter model based on voltage space vector, the hexagon flux trajectory and the principle of DTC are introduced. Four kinds of relationships are analyzed which contains the role of voltage space vector in flux adjust and torque adjust, the relationship between the given value of flux regulator and hexagon flux, the relationship between the tolerance value of torque controller and the output torque, and the relationship between the size of the duty ratio and rotational speed. Based on flux regulating principle, DTC can generate circular flux by adjusting the effecting time of voltage. Based on the regulation principle of flux and torque, With the question of how to change the flux trajectory, the torque ripple and speed by changing the given values of stator flux, the tolerance of torque and the duty cycle in DTC. Direct torque control open-loop simulation model is established by the simulation software–Matlab/Simulink, and create the various modules of the simulation system. The simulation results show that the greater the flux value is, the bigger the flux orbit is, greater torque tolerance leading to greater torque ripple and the greater the duty cycle bring faster speed. The hardware and software of DTC system are designed in this article, part of the experimental testing has been completed. The hardware system design consists of the main circuit and control circuit. The main circuit includes the rectifier circuit, the startup circuit, the filter and inverter ones, Introduce the application of inverter module IPM and design parameters of each device.The control circuit contains control chip DSP (TMS320F28335), sthe isolation circuit, the signal failure circuit and the detection one. The CCS3.3 development environment of software system are introduced. Analysis the main program and the initialization flowchart. Debugging part of speed regulating system.