变频器的控制电路及几种常见故障分析

中文字数:4062,中文页数:5   英文字数: 2463页数:8

 变频器的控制电路及几种常见故障分析
1. 引言
 随着变频器在工业生产中日益广泛的应用，了解变频器的结构、主要器件的电气特性和一些常用参数的作用及其常见故障对于实际工作越来越重要。
2. 变频器控制电路
 给异步电动机供电的主电路提供控制信号的回路，称为控制电路。控制电路由频率、电压的运算电路，主电路的电压、电流检测电路，电动机的速度检测电路，将运算电路的控制信号进行放大的驱动电路，以及逆变器和电动机的保护电路等组成。
 在控制电路增加了速度检测电路，即增加速度指令，可以对异步电动机的速度进行更精确的闭环控制。
 (1)运算电路将外部的速度、转矩等指令同检测电路的电流、电压信号进行比较运算，决定逆变器的输出电压、频率。
 (2)电压、电流检测电路为与主回路电位隔离检测电压、电流等。
 (3)驱动电路为驱动主电路器件的电路，它与控制电路隔离，控制主电路器件的导通、关断。
 (4)I/O输入输出电路使变频器更好地人机交互，其具有多信号的输入，还有各种内部参数的输入。

Frequency changer control circuit and several kind of common fault analysis[ Steven W. Blume. 《Electric Power System Basics For The Nonelectrical Professional》.2007年10月出版
.Wiley-IEEE Press ]

1． Introduction
 Along with the frequency changer in the industrial production the widespread application, understood day by day the frequency changer the structure, the main component electrical specification and some commonly used parameters functions and its the common breakdown are more and more important regarding the practical work. 2.  Frequency changer control circuit
 Provides the control signal to the asynchronous motor power supply main circuit the return route, is called the control circuit. The control circuit by the frequency, the voltage arithmetic circuit, the main circuit voltage, the electric current examination electric circuit, the electric motor speed examination electric circuit, the arithmetic circuit control signal will carry on the enlargement the actuation electric circuit, as well as the inversion and the electric motor protection circuit and so on will compose.
    Increased the speed examination electric circuit in the control circuit, namely increases the speed instruction, and may carry on the more precise closed-loop control to the asynchronous motor speed.
 (1) The arithmetic circuit instruction and so on exterior speed, torque with will examine the electric circuit the electric current, the voltage signal carries on the comparison operation, will decide the inversion output voltage, the frequency.
 (2) The voltage, the electric current examination electric circuit for isolates the examination voltage, the electric current with the host return route electric potential and so on.

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