Product Overview; Internal Frequency Converter Controller Functions - Danfoss VLT Decentral Drive FCD 302 Operating Manual

Introduction
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provide customer service and instruction for
applications.
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for downloads or additional information.

1.5 Product Overview

A frequency converter is an electronic motor controller
that converts AC mains input into a variable AC waveform
output. The frequency and voltage of the output are
regulated to control the motor speed or torque.
In addition, the frequency converter monitors the system
and motor status, issues warnings or alarms for fault
conditions, starts and stops the motor, optimizes energy
efficiency, provides line harmonics protection, 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 communi-
cation network.
®
The VLT Decentral Drive FCD 302 is designed for decentral
mounting, for example, in the food and beverage industry,
or for other material handling applications. With the FCD
302 it is possible to reduce costs by placing the power
electronics decentrally. Central panels are then rendered
obsolete, saving cost, space and effort for installation and
wiring. The basic design is service-friendly, with a
pluggable electronic part and a flexible and "spacious"
wiring box. It is easy to change electronics without the
need for re-wiring.
1.6 Internal Frequency Converter Controller
Functions
Below is a block diagram of the internal components of
the frequency converter. See Table 1.1 for their functions.
1 2 3
4
8
Illustration 1.1 Frequency Converter Block Diagram
MG04F402
Operating Guide
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7
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Area Title Functions
1 Mains input Three-phase AC mains power supply to the
frequency converter.
2 Rectifier The rectifier bridge converts the AC input to
DC current for use within the frequency
converter.
3 DC bus The intermediate DC-bus circuit of the
frequency converter handles the DC current
for internal routing.
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4 DC line Filter the intermediate DC circuit voltage
reactors
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Prove line transient protection
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Reduce RMS current
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Raise the power factor reflected back to
the line
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Reduce harmonics on the AC input
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5 Capacitor Stores the DC power
bank
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Provides a regulated DC current supply
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Provides ride-through protection for short
power losses
6 Inverter The inverter converts the DC into a controlled
PWM AC waveform for a controlled variable
output to the motor.
7 Output to By controlling the voltage and frequency, the
motor frequency converter provides regulated motor
control from 0-50/60 Hz at 100% supply
voltage.
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8 Control Input power, internal processing, output,
circuitry and motor current are monitored to
provide efficient operation and control
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User interface and external commands are
monitored and performed
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Status output and control can be provided
Table 1.1 Frequency Converter Internal Components
1 1
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