Additional Resources; Product Overview; Internal Controller Functions - Danfoss VLT AutomationDrive FC 300 Instruction Manual

Introduction

1.2 Additional Resources

Other resources are available to understand advanced
adjustable frequency drive functions and programming.
•
®
The VLT Programming Guide provides greater
detail on working with parameters and many
application examples.
•
®
The VLT Design Guide is intended to provide
detailed capabilities and functionality to design
motor control systems.
•
Supplementary publications and manuals are
available from Danfoss.
See http://www.danfoss.com/Products/Literature/
Technical+Documentation.htm for listings.
•
Optional equipment is available that may change
some of the procedures described. Reference the
instructions supplied with those options for
specific requirements. Contact the local Danfoss
supplier or visit the Danfoss website for
downloads or additional information.

1.3 Product Overview

An adjustable frequency drive is an electronic motor
controller that converts AC line power input into a variable
AC waveform output. The frequency and voltage of the
output are regulated to control the motor speed or torque.
The adjustable frequency drive can vary the speed of the
motor in response to system feedback, such as position
sensors on a conveyor belt. The adjustable frequency drive
can also regulate the motor by responding to remote
commands from external controllers.
In addition, the adjustable frequency drive monitors the
system and motor status, issues warnings or alarms for
fault conditions, starts and stops the motor, optimizes
energy efficiency, and offers many more control,
monitoring, and efficiency functions. Operation and
monitoring functions are available as status indications to
an outside control system or serial communication
network.

1.4 Internal Controller Functions

Figure 1.3 is a block diagram of the adjustable frequency
drive's internal components. See Table 1.3 for their
functions.
VLT ® AutomationDrive Instruction
Manual
Figure 1.3 Adjustable Frequency Drive Block Diagram
Area
®
MG33AL22 - VLT is a registered Danfoss trademark
Title
•
1 Line power input Three-phase AC line power
supply to the adjustable
frequency drive
•
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 reactors Filter the intermediate DC
circuit voltage
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Provide line transient
protection
•
Reduce RMS current
•
Raise the power factor
reflected back to the line
•
Reduce harmonics on the AC
input
•
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
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7 Output to motor Regulated three-phase output
power to the motor
1
Functions
1-3
1