1 Introduction
1.1 Purpose of the Manual
These operating instructions provide information for safe
installation and commissioning of the filter.
The operating instructions are intended for use by
qualified personnel.
Read and follow the operating instructions to use the filter
properly, and pay particular attention to the safety
instructions and general warnings. Keep these operating
instructions available with the filter at all times.
VLT
®
is a registered trademark.
1.2 Additional Resources
Resources available to understand advanced active filter
functions and programming:
•
The
VLT
®
Advanced Active Filter Service Manual
provides information on troubleshooting and
testing for field service technicians, as well as
disassembly and assembly instructions.
1.3 Product Overview
1.3.1 Working Principle
The VLT
®
Advanced Active Filter is used for harmonic
current mitigation and reactive current compensation. The
unit can integrate with various systems and applications as
a centrally installed filter or be combined with a VLT
®
frequency converter as a packaged low harmonic drive
solution.
M
M
M
130BB717.10
Illustration 1.1 Multiple Working Environments
The active shunt filter monitors all 3-phase line currents
and processes the measured current signal via a digital
signal processor system. The filter then compensates by
actively imposing signals in counter phase to the
unwanted elements of the current (harmonic distortion).
130BB718.10
Illustration 1.2 Active Filter Principles
The filter sets different IGBT switches in real time feeding a
DC voltage into the grid, which creates counter phase
signals. A built-in LCL filter smooths the compensated
current waveform, ensuring that the IGBT switching
frequency and DC component is not imposed to the grid.
The filter operates on generator or transformer supply and
can reduce individual motor loads, non-linear loads, or
Introduction
Operating Instructions
4
Danfoss A/S © 09/2014 All rights reserved.
MG90V302
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