晶闸管直流调速系统变流器课程设计王盛 - 图文

摘要

由于直流电动机具有宽广的调速范围，平滑的调速特性，较高的过载能力和较大的起动、制动转矩，因此被广泛的应用于调速性能要求较高的场合中。在工业生产中，需要高性能速度控制的电力拖动场合中，直流调速系统发挥的重要的作用。本次课程设计是利用两组三相桥式全控整流系统的正反并联来实现晶闸管直流调速系统变流器的连续调速和可逆运行。当使正组变流器处于整流状态时，直流电动机正向运行；当使反组变流器处于整流状态时，直流电动机就能反向运行。

目 录

1 晶闸管直流调速系统变流器设计方案介绍························································ 3 1.1 设计目的······································································································ 3 1.2 设计方案介绍······························································································ 3

1.2.1 设计任务及指标要求···································································· 3

2 主电路的设计········································································································ 4 2.1 主电路的工作原理及原理图······································································ 4 2.2 参数计算······································································································ 9 2.2.1 整流变压器的计算········································································ 9

2.2.2 晶闸管的元件选择········································································ 9 2.3 保护电路···································································································· 10 3 元器件清单·········································································································· 12 4 总结······················································································································ 13 参考文献···················································································································· 14

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1 晶闸管直流调速系统变流器设计方案介绍

1.1 设计目的

电力电子课程设计是电气自动化专业学生在整个学习过程中一项综合性实践环节，是走向工作岗位、从事专业技术之前的一项综合性技能训练，对学生的职业能力培养和实践技能训练具有相当重要的意义。主要目的在于：

1、通过设计提高学生综合运用知识的能力，巩固和扩展学生的知识领域、培养学生严谨的科学态度和提高独立工作的能力；

2、通过设计使学生初步掌握电力电子系统设计方法，熟悉国家有关技术和经济方面的方针政策和安全规程，训练使用设计手册的技术资料的能力；

3、培养学生利用计算机编写技术和绘制设计图样的能力。

1.2 设计方案介绍

1.2.1 设计任务及指标要求

（1） 电网供电电压为380V； （2） 电网电压波动+5%—-10%； （3） 要求连续调速，可逆运行。

(4) 调速比D=15，电流脉动S1<=10%,静差率S<=1%。

1.2.2 设计内容

电动机的额定功率PN=60KW,额定电压UN=220KW,额定电流IN=305A.试设计选择晶闸管电流电动机调速系统的主电路。

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2 主电路的设计

2.1 主电路的工作原理及原理图

1 三相桥式全控整流电路

三相桥式全控整流电路的原理图如图2.1，此电路由变压器和6个晶闸管以及负载组成。变压器二次侧接成星形，而一次侧接成三角形，是为了避免三次谐波电流入电网。其中将阴极连接在一起的三个晶闸管（VT1、VT3、VT5）称为共阴极组；阳极连接在一起的三个晶闸管（VT2、VT4、VT6）称为共阳极组。此外，习惯上希望晶闸管按1到6的顺序导通，为此将晶闸管按图2.1所示的顺序编号，按此编号，晶闸管的导通顺序为VT1-VT2-VT3-VT4-VT5-VT6。

图2.1 三相桥式全控整流电路图

下面将对其原理进行说明：

假设将电路的晶闸管换做二极管，这种情况也就相当于晶闸管触发角α为0°时的情况，此时，对于共阴极组的三个晶闸管，阳极所接交流电压值最高的一个导通，而对于共阳极组的三个晶闸管，则是阴极所接的交流电压值最低的一个导通。这样得到其波形图如下：

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