Internal Controller Functions - Danfoss VLT FC 100 Instruction Manual

Introduction

1.5 Internal Controller Functions

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Figure 1.4 is a block diagram of the adjustable frequency
drive's internal components. See Table 1.3 for their
functions.
Figure 1.4 Adjustable Frequency Drive Block Diagram
1-4
®
VLT HVAC Drive D-Frame
Instruction Manual
Area
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Table 1.3 Adjustable Frequency Drive Internal Components
®
MG16D222 - VLT is a registered Danfoss trademark
Title
•
Mains input Three-phase AC line power
supply to the adjustable
frequency drive
•
Rectifier The rectifier bridge converts
the AC input to DC current to
supply inverter power
•
DC bus Intermediate DC bus circuit
handles the DC current
•
DC reactors Filter the intermediate DC
circuit voltage
•
Prove line transient protection
•
Reduce RMS current
•
Raise the power factor
reflected back to the line
•
Reduce harmonics on the AC
input
•
Capacitor bank Stores the DC power
•
Provides ride-through
protection for short power
losses
•
Inverter Converts the DC into a
controlled PWM AC waveform
for a controlled variable
output to the motor
•
Output to motor Regulated three-phase output
power to the motor
•
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
Functions