毕业设计(论文)-基于AT89S52单片机直流电机PWM控制系统的设计.doc

摘要 电机在各行各业发挥着重要的作用,而电机转速是电机重要的性能指标之一,因而测量电机的转速和电机的调速,使它满足人们的各种需要,更显得重要随着科技的发展,PWM调速成为电机调速的新方式AT89S52和L298控制的直流电机脉宽调制调速系统。利用AT89S52芯片进行低成本直流电动机控制系统的设计，能够简化系统构成、降低系统成本、增强系统性能、满足更多应用场合的需要。系统实现对电机的正转、反转、急停、加速、减速的控制，以及PWM的占空比在LED上的实时显示。 关键词 直流电机；AT89S52；PWM调速；L298 Abstract Motors play important roles in all walks of life and the rotation speed of motors is one of the vatal performance indexs.In addition,it is more important to meet people’s demands by testing the rotation speed and the speed governing of motors.What’s more ,with the development of science,a new way of speed governing turned up which called PWM. With the rapid development of digital technology, micro-controller in all areas of society have been widely used.Because digital system has many advantages which analog system does not have,such as strong anti-interference, simple interface with the PC, easy upgrade and maintenance for system. This project is a speed governing system of the pulse width of DC motor controlled by microcontroller AT89S52 and L298.Making the use of the chip of AT89S52 ,I design a controlling system of DC motor of low cost.It can simplify the system structure reduce system cost,strengthen system performance and meet more needs from more applications.And the system can control the corotation,reversal,scraming,accelerating and slowdown of motors and display the duty ratio of PWM on LED in real time. Keywords DC Motor AT89S52 PMW Speed Automatic L298 目 录 1 绪论 1 1.1直流电机 1 1.1.1直流电机的发展 1 1.1.2直流电机控制方法 1 1.1.3直流电机工作原理 2 1.1.4直流电机主要技术参数 2 1.2单片机及微处理器控制系统的发展 2 2 系统论述 4 2.1设计背景 4 2.2设计思路 4 2.3系统框架设计 4 3 PWM脉宽调制原理 6 3.1 PWM调速原理 6 3.2 PWM调速方法 6 3.3 PWM实现方式 7 3.4 PWM控制流程图 7 4系统硬件设计 8 4.1系统基本组成 8 4.1.1硬件模块组成 8 4.1.2单片机整个控制模块 8 4.2 AT89S52的简介 9 4.2.1 AT89S52主要性能 9 4.2.2 AT89S52主要功能列举 9 4.2.3 AT89S52各引脚功能介绍 10 4.2.4 AT89S52的内部资源 12 4.3 L298电机驱动模块 12 4.3.1 L298电机驱动简介 13 4.3.2 L298内部的原理图 13 4.3.3 L298内部H桥驱动电路 13 4.3.4 L298引脚符号及功能 15 4.3.5 L298的逻辑功能 15 4.4.6本系统中单片机与L298的连接 16 4.4 LED数码管显示 1