Description Of Operation - Danfoss VLT AQUA Drive FC 202 Design Manual

Product Overview
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1
0
0 12,5
®
1 VLT
AQUA Drive FC 202
2 Star/delta starter
3 Soft starter
4 Start directly on line power
Figure 2.8 Start-up Current

2.2 Description of Operation

The adjustable frequency drive supplies a regulated
amount of AC line power to the motor to control its speed.
The adjustable frequency drive supplies variable frequency
and voltage to the motor.
The adjustable frequency drive is divided into four main
modules:
•
Rectifier
•
Intermediate DC bus circuit
•
Inverter
•
Control and regulation
Figure 2.9 is a block diagram of the internal components of
the adjustable frequency drive. See Table 2.3 for their
functions.
Figure 2.9 Adjustable Frequency Drive Block Diagram
MG20N622
Design Guide
4
3
2
25 37,5 50Hz
Full load
& speed
Danfoss A/S © 09/2014 All rights reserved.
Area Title
•
3-phase AC line power supply to
Line power
1
the adjustable frequency drive.
input
•
The rectifier bridge converts the
AC input to DC current to supply
2 Rectifier
inverter power.
•
Intermediate DC bus circuit
3 DC bus
handles the DC current.
•
Filter the intermediate DC circuit
voltage.
•
Prove electrical transient
protection.
•
Reduce RMS current.
4 DC reactors
•
Raise the power factor reflected
back to the line.
•
Reduce harmonics on the AC
input.
•
Stores the DC power.
•
5 Capacitor bank Provides ride-through protection
for short power losses.
•
Converts the DC into a controlled
PWM AC waveform for a
6 Inverter
controlled variable output to the
motor.
•
Regulated 3-phase output power
7 Output to motor
to the motor.
•
Input power, internal processing,
output, and motor current are
monitored to provide efficient
operation and control.
•
User interface and external
8 Control circuitry
commands are monitored and
performed.
•
Status output and control can be
provided.
Table 2.3 Legend to Figure 2.9
1. The adjustable frequency drive rectifies AC
voltage from line power into DC voltage.
2. The DC voltage is converted into an AC current
with a variable amplitude and frequency.
The adjustable frequency drive supplies the motor with
variable voltage/current and frequency, which enables
variable speed control of 3-phased, standard asynchronous
motors and non-salient PM motors.
Functions
2
19
2