摘要上个世纪60年代左右以前是以旋转变流机组供电的直流调速系统为主，还有一些静止式水银整流器供电的直流调速系统。20世纪60年代以来以晶闸管组成的可控直流供电系统逐步取代了直流机组和水银整流器。20世纪80年代末期全数字控制的直流调速系统迅速取代了模拟控制的直流调速系统。46125
现如今，伴随随一些功率大的电子器件的快速萌生，变频调速技术已经日益成熟起来了，而且渐渐成为主导，但这完全不会使得传统的直流调速技术淡出日常生产活动之中，而且恰恰相反，最近一段时间交流变频调速在控制精度技术问题上面停滞不前，难以克服暂时，这样子直流调速系统的优势大大的出现了。直流调速依旧是是现如今最稳定，精确度最高的调速方法。例如在对控制精确度有比较高的要求的造纸行业依然离不开直流调速这一类的装置，所以对直流调速系统的研究开发学习还是很有意义的。鉴于直流调速系统在国民经济的重要作用，对直流调速系统的研究和开发显得意义深远。
毕业论文关键词：直流调速；微机控制；PWM；
ABSTRACT
Before 1960s, it was mainly used to supply the DC speed regulation system with the rotary variable flow unit, and some of the DC speed regulating system. In 1957, the Ge Corp of the United States of York made the world's first A.R thyristor, which marks the beginning of the era of power electronics. Since 1960s the thyristor controlled DC power supply system composed of gradually replaced the DC generator and mercury rectifier. DC speed control system at the end of the 1980s digital control is rapidly replacing the DC speed control system simulation and control.
At present, with the rapid development of the power electronic devices, AC variable frequency speed control technology has matured and become the mainstream of the practical application, but this does not mean that traditional DC speed control technology already completely withdraw from the stage of practical application. On the contrary, in recent years, the AC frequency conversion speed control in the control of the improvement of the accuracy of the bottleneck, so the advantages of DC speed is revealed. DC speed regulation is still the most reliable, the highest accuracy of the speed control method. For example, in the control of the precision of the paper, turntable, turbine positioning system can not be separated from DC speed control device, therefore, to strengthen the research of DC speed control system is very necessary. In view of the important role of DC speed control system in the national economy, industrial and agricultural production and national defense, it is necessary to make further research and development of DC speed regulating system.
Key words：Measurement of rotating speed；Microcomputer control；PWM；
目 录
第一章 绪 论 1
1.1直流调速系统的发展现状及前景 1
1.2课题的提出及意义 2
1.3本课题所研究的主要内容 3
1.4 PWM变频调速概述 3
第二章 总体设计 4
2.1基本原理分析 4
2.1.1直流PWM变换器的基本原理、电路结构和工作状态 4
2.1.2 PWM变频调速 6
2.2 直流电机调速系统设计 7
2.2.2 总体方案选择 8
2.2.3 电机调速控制模块方案比较与选择 8
2.2.4 直流电机PWM调速原理 9
第三章 硬件系统设计 11
3.1 系统硬件组成 11
3.2 AT89S51单片机特性及管脚说明 11
3.3 直流电源部分 13
3.4 电机驱动电路 13 AT89S51单片机PWM直流调速系统的微机控制:http://www.youerw.com/zidonghua/lunwen_47783.html