高压变频器使用手册 - 中英文版-第3章

第3章 系统原理Chapter 3 System Theory

第3章 ChapterⅡ

系统原理 System Principle

本章主要介绍PowerSmartTM变频调速系统的原理

The chapter mainly introduces the principle of PowerSmartTM Variable

Frequency Speed-Regulating Device

3.1 系统的单线原理图

3.1 Single-line Schematic Diagram of the System

本高压变频调速系统主要由PowerSmartTM系列变频器、远控操作箱、机旁操作箱及旁路开关柜等部分组成。其中远控操作箱、机旁操作箱和旁路开关柜为选配设备，旁路开关柜可以采用手动或自动旁路形式，根据用户具体要求设计。工频自动旁路系统的单线原理图如下所示：

The high-voltage Variable Frequency Speed-Regulating Device is mainly composed of PowerSmartTM series drive, remote-control operation box, machine-side operation box, bypass switch cabinet and so on, among which remote-control operation box, machine-side operation box and bypass switch cabinet are matching equipments, bypass switch cabinet may be adopted manual or automatic bypass form, which is designed according to concrete requirements of users. The single-line schematic diagram of power frequency automatic bypass system follows as below:

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第3章 系统原理 Chapter 3 System Theory

图3-1 系统的单线原理图

Fig3-1 Single-line Schematic Diagram of the System

注：旁路开关柜中KM2、KM3采用高压真空接触器，QF1采用高压真空断路器。 Note: KM2 and KW3 in bypass switch cabinet adopt high-voltage vacuum contactor

and QF1 adopts high-voltage vacuum circuit breaker.

3.1.1 旁路系统的运行原理

3.1.1 Operation Theory of Bypass System

如上图所示，当系统在变频方式下运行时，QF1断开，KM2和KM3闭合；当系统在工频方式下运行时，KM2与KM3则断开，QF1闭合。

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第3章 系统原理Chapter 3 System Theory

As above figure, when the system operates with drive mode, QF1 opens , KM2 and KM3 close ; when the system operates with power frequency mode, KM2 and KM3 open, QF1 closes .

旁路开关的作用是实现变频/工频运行方式的切换，以方便变频器的维护和检修。当变频器故障时，合上旁路高压真空断路器，使电机进入工频状态运行，此时可检修变频器。但是，检修过程中应注意柜内尚有直流剩余电压，应待其放掉后进行。当电机需要变频运行时，应先将电机停掉，再将旁路开关柜投向变频状态，然后启动变频器。 The function of bypass switch is to realize the switch of drive/power frequency mode. When malfunction of drive, close up bypass high-voltage vacuum circuit breaker and make motor to operate with power frequency mode, at this point drive may be checked. However, DC residual voltage may exist in the process of examining and repairing, which should be paid attention to and let out. When motor needs frequency-changing operation, firstly, close up motor, switch bypass switch cabinet to frequency-changing status and then start up drive.

3.1.2 远控操作箱或机旁操作箱的运行原理

3.1.2 Operation principle of Remote-control Operation Box and Bypass Operation Box.

远控操作箱一般安装在电机的操作室内，能够指示变频器的运行状态，如：输出频率、输出电流等。通过远控操作箱可以启动、停止、升速和降速变频器。

Generally, remote-control operation box is installed in the operation room of motor, which can instruct the operation status of drive, such as output frequency, output current and so on. Drive may be started, stopped, raised and reduced speed by remote-control operation box.

机旁操作箱安装在电机旁，也是用来监控变频器运行状态的，它是由特殊用户定制的，目前应用较少。

Machine-side operation box is installed on side of motor, which is also used to monitor operation status of drive; it is customized by particular user and has little application at present.

3.2

PowerSmartTM系列变频器的基本原理

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第3章 系统原理 Chapter 3 System Theory

3.2 Basic Principle of PowerSmartTM Series Drive

PowerSmartTM系列高压变频器是一种单元串联、多重叠加的高-高型变频器，它主要由输入切分变压器、功率单元柜和控制单元柜等三部分组成。

PowerSmartTM Series High-voltage Drive is unit series connection and multiple overlay high-high model drive, which is mainly composed of segmentation transformers, power unit cabinet and control unit cabinet.

本高压变频器的内部连线图如下所示：

The inner connecting graph of the high-voltage drive follows as below:

图3-2 内部连线图

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第3章 系统原理Chapter 3 System Theory

Fig3-2 Inner Connecting Graph

三相高压电经用户侧的高压开关柜进入本变频器。

Three-phase high-voltage electricity enters into the drive via high-voltage switch cabinet of user.

首先，经过输入变压器的降压、移相，然后供给功率单元柜中的功率单元。为功率单元供电的各个副边绕组是相互独立、相互隔离的，每台单元均为三电平单相输出。这些单元分为三部分，每部分组成一相。每一相中相邻功率单元的输出端首尾相串，这三相之间最终形成星形连接方式为高压电动机提供可变频变压的高压交流电。

Firstly, input transformer performs voltage reducing and phase shift for three-phase high-voltage electricity, and then supplies it to power unit of power unit cabinet. All secondary windings that supply power for power unit are independent and isolated with each other; each unit is three-level single-phase output. These units are divided into three parts, each part forms a phase. The input ends of adjacent power units in each phase are connected from beginning to end. Y connection mode is finally formed among the three-phase, which supplies high-voltage AC current with variable frequency and variable voltage for high-voltage motor.

3.3 额定电压为6KV的变频器基本原理

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