PWM控制直流调速系统毕业设计(有全套图纸).doc

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PWM控制直流调速系统设计
摘 要
在电气时代的今天，电动机在工农业生产、人们日常生活中起着十分重要的作用。直流电机是最常见的一种电机，在各领域中得到广泛应用。研究直流电机的控制和测量方法，对提高控制精度和响应速度、节约能源等都具有重要意义。电机调速问题一直是自动化领域比较重要的问题之一。不同领域对于电机的调速性能有着不同的要求，因此，不同的调速方法有着不同的应用场合。
本文基于PWM的双闭环直流调速系统进行了研究，并设计出应用于直流电动机的双闭环直流调速系统。首先描述了变频器的发展历程，提出了PWM调速方法的优势，指出了未来PWM调速方法的发展前景，点出了研究PWM调速方法的意义。应用于直流电机的调速方式很多，其中以PWM变频调速方式应用最为广泛，而PWM变频器中，H型PWM变频器性能尤为突出，作为本次设计的基础理论，本文将对PWM的理论进行详细论述。在此基础上，本文将做出SG3525单片机控制的H型PWM变频调速系统的整体设计，然后对各个部分分别进行论证，力图在每个组成单元上都达到最好的系统性能。

关键词：直流调速 ；双闭环 ；PWM ；SG3525 ；直流电机

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DC-drive speed system with PWM

ABSTRACT

In electrical time's today, the electric motor in the industry and agriculture production, the people daily life is playing the very vital role. The direct current machine is the most c
Key word: DC speed regulation ；Double-loop ；PWM ；SG3525；DC moter；

II

目 录
摘要·····································································ⅠAbstract··································································Ⅱ前言·····································································1第1章 直流调速系统的方案设计············································2
1.1 设计技术指标要求···················································2
1.2 现行方案的讨论与比较···············································2
1.3 选择PWM控制调速系统的理由·······································4
1.4 选择IGBT的H桥型主电路的理由·····································4
1.5 采用转速、电流双闭环的理由·······································5第2章 PWM控制直流调速系统主电路设计 ··································6
2.1 主电路结构设计·····················································6
2.1.1 PWM变换器介绍···························································6
2.1.2 泵升电路·································································13
2.2 参数设计···································································13
2.2.1 IGBT的参数······························································13
2.2.2 缓冲电路参数····························································14
2.2.3 泵升电路参数····························································14
第3章 PWM控制直流调速系统控制电路设计·································15 3.1 PWM信号发生器···························································15
3.1.1 SG3525芯片的主要特点·············································15
3.1.2 SG3525引脚各端子功能·············································16
3.1.3 SG3525的工作原理·················································18
3.2 转速、电流双闭环设计················································18
3.2. 1 转速、电流双闭环系统的组成·······································18
3.2.2 转速、电流双闭环调速系统的静特性··································19
3.2.3 电流调节器设计···················································22
3.2.4 速度调节器设计···················································24

第4章 系统实验验证······················································26
4.1 系统结框图·························································26
4.2 系统工作原理·······················································26
4.3 系统单元调试·······················································27
4.3.1 基本调试·························································27
4.3.2 脉宽发生单元的整定···············································27
4.3.3 转速反馈调节器、电流反馈调节器的整定······························28
4.4 实验结果···························································28
4.4.1 开环机械特性测试·················································28
4.4.2 闭环机械特性测试·················································29
结束语···································································30
参考文献·································································31
致谢·····································································32

PWM控制直流调速系统设计

前 言

在现代科学技术革命过程中，电气自动化在20世纪的后四十年曾进行了两次重大的技术更新。一次是元器件的更新，即以大功率半导体器件晶闸管取代传统的变流机组，以线形组件运算放大器取代电磁放大器件。后一次技术更新主要是把现代控制理论和计算机技术用于电气工程，控制器由模拟式进入了数字式。在前一次技术更新中，电气系统的动态设计仍采用经典控制理论的方法。而后一次技术更新是设计思想和理论概念上的一个飞跃和质变，电气系统的结构和性能亦随之改观。在整个电气自动化系统中，电力拖动及调速系统是其中的核心部分。
直流电压输入为300V的情况下，发电机输出首先空载，从零开始逐渐调大给定电压Ug，使电动机转速接近1200rpm，然后在发电机的电枢绕组接入负载电阻Rg，逐渐增大电动机负载（即减小负载的电阻值），直至电动机的电枢电流Id=1.1A，即可测出系统静态特性，测定n=f（Id）并记录于下表中：
Id(A)
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
n(rpm)
1208
1208
1208
1207
1209
1210
1214
1216
1215
改变电机的转向，重复上述的步骤：
n(rpm)
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
n(rpm)
1200
1197
1193
1193
1200
1203
1205
1210
1215
再降低给定电压Ug，再测试800rpm的静态特性曲线，记录于下表中：
Id(A)
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0

n(rpm)
800
801
801
801
800
800
799
799
802

图4-2 闭环系统特性曲线

结束语
“PWM双闭环直流调速系统” 的设计 ，是在DJDK－1型电力电子技术及电机控制实验装置上进行的。测定直流电动机的各项电气参数和时间常数，并应用经典控制理论的工程设计方法设计转速和电流双闭环直流调速系统。以SG3525为核心实现PWM脉宽调速，形成无静差的转速电流双闭环控制。
PWM双闭环直流调速系统，具有调速简单、调速范围大、精度高、速度平稳、电流脉动小、电机温升低等优点，使调速各项性能指标大为提高。
纵观整个设计，经典部分是已学过的知识，通过毕业设计深入理解了工程设计方法，扩展了知识面，各门课程综合应用，收益颇多，使我对直流调速系统的控制有了更深的认识。但由于理论水平有限，仍有许多不足之处有待解决。

参考文献
1 DJDK-1型电力电子技术及电机控制试验装置实验指导书
2 夏得砛，翁贻方.自动控制理论．第2版．机械工业出版社，2007
3 陈伯时．电力拖动自动控制系统．第2版．机械工业出版社，2003
4 王兆安，黄俊．电力电子技术．第4版．机械工业出版社，2007
5 杨兴姚．电动机调速的原理及系统．北京水利电力出版社，2003

6 刘军．孟祥忠．电力拖动自动控制系统．机械工业出版社，2007
7 王华强. 直流电机调速系统的工程设计方法的探讨. 荆门职业技术学院学报. 2002
8 吴守箴，藏英杰.电气传动的脉宽调制控制技术[M] .机械工业出版社，1995
9 William L.Brogan, Ph.D. Modern Control Theory．NewJersey：Prentice-Hall，Inc.1985
10 Leonhard W.Control of Electrical Drives.Springer-Verlag，Inc.2001
11 Kuo B.C.Automatic Control Systems.Prentice-Hall, Inc.2002
12 工控相关网站

致 谢
首先要感谢我的指导老师—郑载满老师。在他的悉心指导下，我才得以顺利的完成本次毕业设计。他从最初就为我们制定了周密科学的工作任务安排，每次都很认真的查看我们的工作日志完成情况，对于我们的提问也总给予耐心的解答。
我还要感谢同组的同学，跟他们一起讨论相关的课题，使我的思路得以极大的开阔，并能发现自己在某些内容上的欠缺。另外，我也深深的感受到了同学间的互相帮助和友谊。这也是我顺利完成毕业设计的一大动力。
还有许多在论文完成过程中给予我帮助的人，在此不一一列举了，一并表示最衷心的感谢。

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