三相异步电动机调速系统设计(精)

Anhui Vocactional & Technical College of Industry & Trade

毕业论文

三相异步电动机调速系统设计

Three-phase asynchronous motor drive system design

所在系院：电气与信息工程系

专业班级：、

机电一体技术

学生学号：43

学生姓名：叶海英

指导教师：王琳

；

2013年3月23日

安徽工贸职业技术学院

毕业设计（论文）任务书系（院）专业班级

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摘要

本文所讨论的是三相异步电动机的串级调速的基本原理与实现方法。对于一般交流电动机的调速，我们都是从电动机的定子侧引入控制变量（改变定子供电电压、频率）来实现的，这对于转子处于短路状态的三相笼型异步电动机是唯一的途径。但是，对于绕线式异步电动机来说，其转子绕组能够通过变量以实现调速。绕线式异步电动机转子侧的控制变量有电流、电动势、电阻等。通常转子电流随负载的大小决定，不能任意调节；而转子回路阻抗的调节属于耗能型调速，缺点较多，所以转子侧的控制变量只能是电动势。在发挥绕线式异步电动机转子的可控性优势的基础上，提高调速性能需要从两方面着手：

1从节能角度考虑，应将损耗在转子附加电阻上的能量吸收，转化成别的有用的能量或反馈到电网，以提高传动系统的效率

2从高性能调速要求考虑，应用控制理论，将其组成闭环调速控制系统，满足调速精度、动态响应等指标的要求。

综合所述，利用串级调速系统，是使绕线式异步电动机实现高性能调速的有效办法。用转子串反电动势来代替电阻，吸收转差功率；用双闭环控制提高系统的静、动态性能。把这种用附加电动势的方法将转差功率回收利用的调速称为双闭环串级调速。

【关键字】节能，双闭环，调速，变极

Abstract

This paper discusses the three-phase induction motor cascade speed control principle and Realization method. For the general AC motor speed, we are all from the motor stator side of the introduction of the control variable ( a change in the stator voltage, frequency to achieve, the

rotor in a short-circuit state AC squirrel cage rotor asynchronous motor is the only way. However, for winding type asynchronous motor, due to

its rotor winding through the variables to achieve the speed. The rotor side of the control variables are the current, electromotive force, resistance. Usually the rotor current with load determines the size, cannot be adjusted; and the rotor loop impedance regulator belonging to the energy dissipation type adjustable speed, a lot of problems, so the rotor side control variables can only be electromotive force. In the

play of wound-rotor asynchronous motor control on the foundation of the advantage, improve speed performance to need from two aspects:

1 from the energy point of view, should be the loss in rotor of

additional resistance on energy absorption, energy or converted into other useful feedback to the grid, to enhance the transmission

efficiency of the system

2 from the high performance speed requirements are taken into account, the application of control theory, the closed loop speed control system composition, meet the accuracy of speed, dynamic response requirement.

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Above all, use of cascade speed regulation system, is to make the

winding type asynchronous motor speed and effective measures to realize high performance. With rotor EMF to replace resistor, absorb slip power; double closed-loop control system can improve the static, dynamic performance. This additional electromotive force method will slip power recovery speed is known as a double closed loop cascade speed control.

【eywords 】Energy saving, Double closed-loop, Speed control, Variable pole