单片机控制直流电动机调速系统

电子机电论文编号:JD409字数:24813.页数:58  

目  录
摘  要 .....................................................................i
Abstract ...................................................................ii
目  录 .....................................................................iii
1  绪论 .....................................................................1
1.1 序言 ....................................................................1
1.2 直流调速系统发展概况.....................................................1
1.3 单片机主流产品介绍.......................................................2
2  直流脉宽调速系统的理论研究................................................3
2.1 直流电动机的调速方案.....................................................3
2.2 直流电机PWM调速原理 .....................................................3
2.3 双闭环可逆直流PWM调速系统原理............................................6
2.3.1 转速、电流双闭环调速系统的组成 ........................................6
2.3.2 稳态结构图和静特性.....................................................6
2.3.3 双闭环脉宽调速系统的动态性能 ..........................................7
3 双闭环可逆直流PWM调速系统的硬件设计 .......................................12
3.1 单片机的选择.............................................................13
3.2 电流检测电路 ............................................................15
3.2.1 AD574芯片及引脚功能简介 ...............................................16
3.2.2 AD574的工作原理........................................................17
3.2.3 AD574与89C51单片机的接口电路 ..........................................17
3.3转速测量电路 .............................................................18
3.3.1 M/T法测速原理 .........................................................18
3.3.2 8253可编程定时器/计数器芯片 ...........................................19
3.3.3 转速测量硬件电路 ......................................................20
3.4 转速设定/显示电路 .......................................................21
3.4.1 8279可编程键盘、显示接口芯片 ..........................................21
3.4.2 键盘/显示接口电路 .....................................................23
3.5 PWM调制信号产生电路 .....................................................24
3.5.1 DAC1208内部结构与引脚功能 .............................................24
3.5.2 DAC1208与89C51单片机的接口 ............................................25
3.5.3 专用PWM集成电路芯片TL494 ..............................................26
3.5.4 TL494电路实现..........................................................27
3.6 直流电机PWM驱动电路 .....................................................28
3.6.1 LMD18200驱动电路原理...................................................28
3.6.2 专用直流电动机驱动芯片LMD18200 ........................................31
4 双闭环可逆直流PWM调速系统的软件设计 .......................................34
4.1 软件的结构设计...........................................................34
4.2 主程序设计...............................................................36
4.3 电流调节器和转速调节器的算法及软件实现...................................37
全文总结.....................................................................41
致  谢 ......................................................................42
参考文献 ....................................................................43
附  录 ......................................................................44

摘      要 

本文介绍了一种基于单片机控制的PWM直流电机调速系统，系统以89C51单片机为核心,以小型直流电机为控制对象,实现双闭环PI控制。系统包括转速给定、转速显示、转速检测、电流检测、PWM脉宽信号产生电路以及直流电机驱动电路。从直流调速系统原理出发，逐步建立了双闭环直流PWM调速系统的数学模型，给出了该系统的详细设计思路、软硬件设计、电路结构和采用PI控制算法的控制程序流程。在芯片选择方面，以89C51为控制核心，分别采用了AD574电流模/数转换、8253转速M/T法测量、8279转速设定/显示、DAC1208/TL494PWM波形产生、LDM18200电机驱动等芯片与一些外围电路。该系统具有较好的控制精度,可以在中小功率直流电动机上广泛应用。

关键词: 单片机,直流电机,调速系统,PWM,双闭环控制

Abstract

A kind of PWM direct current motor speeding control system by this paper is introduced based on Single-Chip Computer control.In this system, taking the single- chip computer89C51 as the core part and the small-type of DC motor as the control object.a double closed-loop PI control is implemented.This system consists of rotation setting,display and detection, current sensing, PWM pulse signals generator circuit and the DC drive circuit.Beginning with the theory of the DC timing system,this article has built up the maths model of the reversible DC-PWM timing system with a dual-converter and dual-closed-loop,Given the details of the system design, software and hardware design, circuit structure and control algorithms using the PI process control proce- dures. In the chip selection, to 89C51 for the control of the core,By using the AD574 current A/D converter, 8253 Speed M/T measurement, 8279 speed settings/Show, DAC1208/TL494PWM waveform generator, LDM18200 motor drive, such as chips and some external circuit.The system has better control accuracy, in small and medium-sized power on the wider use of DC motor.

Key  words: single-chip computer,DC motor, adjustment speed system, PWM,double closed-loop control