Product Overview; Internal Frequency Converter Controller Functions - GE AF-650 GP Design And Installation Manual

Introduction

1.4 Product Overview

A frequency converter is an electronic motor controller
1 1
that converts DC into a variable AC waveform output. The
frequency and voltage of the output are regulated to
control the motor speed or torque. The frequency
converter can vary the speed of the motor in response to
system feedback, such as position sensors on a conveyor
belt. The frequency converter can also regulate the motor
by responding to remote commands from external
controllers.
The frequency converter offers many control, monitoring,
and efficiency functions such as:
•
Monitoring the system and motor status
•
Issuing warnings or alarms for fault conditions
•
Starting and stopping the motor
•
Optimizing energy efficiency
Operation and monitoring functions are available as status
indications to an outside control system or serial communi-
cation network.
1.5 Internal Frequency Converter Controller
Functions
Illustration 1.9 is a block diagram of the frequency
converter's internal components.
Illustration 1.9 Frequency Converter Block Diagram
Area
1 Mains input
2 Rectifier
3 DC-bus
14
Title Functions
•
3-phase AC mains supply to the
frequency converter.
•
The rectifier bridge converts the
AC input to DC current to
supply inverter power.
•
Intermediate DC-bus circuit
handles the DC current.
Area
4 DC reactors
5 Capacitor bank
6 Inverter
7 Output to motor
8 Control circuitry
Table 1.2 Legend to Illustration 1.9
DET-767c All rights reserved.
Title Functions
•
Filter the intermediate DC circuit
voltage.
•
Prove mains transient
protection.
•
Reduce RMS current.
•
Raise the power factor reflected
back to the line.
•
Reduce harmonics on the AC
input.
•
Stores the DC power.
•
Provides ride-through protection
for short power losses.
•
Converts the DC into a
controlled PWM AC waveform
for a controlled variable output
to the motor.
•
Regulated 3-phase output
power to the motor.
•
Input power, internal processing,
output, and motor current are
monitored to provide efficient
operation and control.
•
User interface and external
commands are monitored and
performed.
•
Status output and control can
be provided.
MG35M402