1.6.1 Block Diagram of the Frequency
Converter
is a block diagram of the internal
components of the frequency converter.
M
7
6
3
4
5
2
1
8
130BF760.10
4
M
7
6
3
4
5
2
1
8
9
J1–J5
J6–J7
Area
Component
Functions
1
Mains input
•
AC mains supply to the
frequency converter.
2
Rectifier
•
The rectifier bridge converts
the AC input to DC current to
supply inverter power.
3
DC bus
•
Intermediate DC-bus circuit
handles the DC current.
4
DC reactor
•
Filters the intermediate DC
circuit current.
•
Provides mains transient
protection.
•
Reduces the root mean square
(RMS) current.
•
Raises the power factor
reflected back to the line.
•
Reduces harmonics on the AC
input.
Area
Component
Functions
5
Capacitor bank
•
Stores the DC power.
•
Provides ride-through
protection for short power
losses.
6
Inverter
•
Converts the DC into a
controlled PWM AC waveform
for a controlled variable
output to the motor.
7
Output to motor
•
Regulated 3-phase output
power to the motor.
8
Control circuitry
•
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.
9
Brake chopper
•
Brake chopper is used in the
DC intermediate circuit to
control DC voltage when the
load feeds energy back.
Illustration 1.1 Example of Block Diagram for a Frequency
Converter
Introduction
VLT
®
AutomationDrive FC 360
4
Danfoss A/S © 03/2017 All rights reserved.
MG06A702
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