文档介绍：摘要
当今，自动化控制系统已经在各行各业得到了广泛的应用和发展，而直流驱动控制作为电气传动的主流在现代化生产中起着主要作用。长期以来，直流电动机因其转速调节比较灵活，方法简单，易于大围平滑调速，控制性能好等特点，一直在传动领域占有统治地位。[2]
本毕业设计主要是通过PWM调速器实现直流电机的正转、反转、加速、减速、停止等操作，并实现电路的仿真。为实现系统的微机控制，在设计中，采用了AT89C51单片机作为整个控制系统的控制电路的核心部分，配以各种显示、驱动模块，实现对电动机转速参数的显示和测量；由命令输入模块、光电隔离模块及H型驱动模块组成。采用带中断的独立式键盘作为命令的输入，单片机在程序控制下，不断给光电隔离电路发送PWM波形，，采用PWM调速方式，通过改变PWM的占空比从而改变电动机的电枢电压，进而实现对电动机的调速。设计的整个控制系统，在硬件结构上采用了大量的集成电路模块，大大简化了硬件电路，提高了系统的稳定性和可靠性，使整个系统的性能得到提高。
关键词：直流电机，AT89C51单片机，PWM调速，仿真
Abstract
Nowadays, automation control system has been widely used in all walks of life and development, and DC drive control as a mainstream electric drive plays a major role in the modernization of production. For a long time, because the DC motor speed regulation is more flexible, simple, easy-to-large-scale smooth speed control performance and good features, has been the dominant in the field of transmission.
The graduation project is mainly achieved by PWM DC motor speed controller forward, reverse, speed up, slow down, stop and other operations, and to achieve the simulation of the circuit. To achieve microputer control system design, using a control circuit AT89C51 microcontroller as the core of the entire control system part, with various display driver module, the parameters of the motor speed display and measurement; by the mand input module optical isolation module and H-drive module. Using a separate keyboard with interrupt input as a mand, the microcontroller under program control, continuous optical isolation circuit to transmit PWM waveform, H-drive motor reversing control circuit is pleted in the design, using PWM speed control mode by changing thus changing the duty cycle of the PWM motor armature voltage, and thus realize the motor speed. The whole control system design, the hardware structure with a lot of integrated circuit module, greatly simplifying the hardware circuit to improve the stability and reliability of the system, so that overall system performance