异步电动机功率因数控制系统的研究

包括大图,文档,外文翻译,文档字数:20803.页数:51  文档编号:JD383

摘要

本文首先推导出异步电动机的功率因数关系表达式并以异步电动机的功率因数作为控制对象，使电动机一直处于较高的功率因数下运行，减少无功能量的损耗，从而达到节能的目的。仿真结果表明，当电机处于空载和轻载时，可取的一定的节能效果。
异步电动机是工农业生产中使用量以及耗电量最多的一种电气设备。在电气拖动系统中，往往以最高的负载加上裕量来设计参数以及选型。而在实际的运行中，负载的变化会随着实际的需要量而变化，因此，就会遇到功率电机拖动小负载的情况。通过对电动机的负载电流，电动机负载电压及功率因数的分析，就可发现：当电动机为空载或轻载的时候，电动机的功率因数较低；当电动机为满载，负载的功率因数较高。较高的功率因数是节能降耗的一项重要的任务。变频调速是一种典型的直流电动机高调速方法，它既适用于异步电动机，也适用于同步电动机。交流电动机采用变频调速不但能无级调速，而且根据负载的不同，通过适当的调节电压与频率之间的关系，可使电机始终运行在高效率区，并保证良好的动态性能。
关键字：单片机；功率因数；异步电动机；节能

Abstract

This text derive and offer asynchronous power factor relation of motor expressed and show at first, and regard power factor of the asynchronous motor as the target of controlling , make the motor run under higher power factor , Reduce the loss which does not have function quantity, thus achieve the energy-conserving goal. Emulation result indicates , when the motor is in unloaded and light year, can make certain energy- conserving result .
 Asynchronous motor is used in industrial and agricultural production and consumption of a maximum of electrical equipment. In electric drive system, often with the highest load plus margin to design parameters and selection. In actual operation, the load will change with the actual requirements and changes, it will have electrical power load drag on the situation. Through the load current motor, motor load voltage and power factor analysis, can be found: When the motor for light-load or no load when the motor power factor lower when the motor for the full load of high power factor. Higher energy saving power factor is an important task. Frequency Control is a typical high-speed DC motor way, it applies to asynchronous motor, but also to synchronous motor. AC motors can be used not only VVVF stepless speed regulation, but under different load, through the appropriate voltage and frequency adjustment of the relationship between the motor will always run at high efficiency, and to ensure good dynamic performance.
Key word: One-chip computer; Power factor; Asynchronous motor; Energy-conservation
目录
0 引言………………………………………………………………………………1
1概述 ……………………………………………………………………………2
1.1 调速的意义与发展状况…………………………………………………………2
1.1.1交流调速技术发展的概况与趋势……………………………………………2
1.1.2变频调速的意义和发展概况………………………………………………2
1.2变频调速的一些基本概念………………………………………………………3
1.2.1交流电动机调速方式…………………………………………………………3
1.2.2变频调速 ……………………………………………………………………4
1.2.3变频装置 ……………………………………………………………………10
1.2.4正弦波脉宽调制（SPWM）变压变频器…………………………………… 13
1.3本文档的目的和任务………………………………………………………… 19
2异步电动机的功率因数 …………………………………………………………20
3带有功率因数自动控制的异步电动机变频调速系统的设计………………… 25
3.1主电路的设 ……………………………………………………………………25
3.2单片机及其扩展……………………………………………………………… 26
3.2.1单片机简介…………………………………………………………………26
3.2.2 8098及其扩展…………………………………………………………… 27
3.3 SPWM波的形成与驱动…………………………………………………………38
3.3.1 SPWM波的形成………………………………………………………………38
3.4反馈信号的测取和功率因数的输入…………………………………………43
3.4.1 电压和电流反馈信号的测取………………………………………………43
3.4.2 转速检测……………………………………………………………………44
3.5 系统原理与程序流程……………………………………………………… 44
4 技术经济分析 ……………………………………………………………………47
5结论…………………………………………………………………………… 48
致谢……………………………………………………………………………… 49
参考文献 …………………………………………………………………………50
附录 A  译文…………………………………………………………………… 51
附录 B  外文文献……………………………………………………………… 58

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