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ANTRIEBSTECHNIK
2
©
KEB Antriebstechnik, 1998
All Rights reserved
Chapter
Section
Page
Date
2
1
3
KEB COMBIVERT F4-F
Name: Basis
11.12.98
Product Description
Summary
=
~
=
~
U
N
R
C
W
U
V
U
ZK
L1
L2
(L3)
M
3 ~
2.1.1 Features of KEB
COMBIVERT F4-F
2.1
Product Description
KEB
COMBIVERT
F4-F
8 parameter sets
17 parameter groups
Prog. Operator menu
1 prog. relay output
7 prog. digital inputs
2 prog. digital outputs
2 prog. analog outputs
2 prog. analog inputs
Hardware current limit
Jogging-function (prog.)
Protective equipment
Prog. filter for analog and digital inputs
Software In-/Outputs
Adjustable balancing of the ramps
Hour meter
2.1.2 Function Principle
The power circuit of a frequency inverter consists basically of a mains rectifier, the
DC-link and an inverter at the output. The mains rectifier consists of an single or
three-phase bridge connection, the single-phase design is restricted to small powers.
It converts the AC-voltage of the mains into a DC-voltage, which is smoothed by the
DC-link capacitor, thus in the ideal case (inverter unloaded) the DC-link is charged
with a voltage of U
ZK
=
√
2
.
U
N.
Since during the charging of the DC-link capacitor very high currents flow for a short
time which would lead to the tripping of the input fuses or even to the destruction of
the mains rectifier, the charging current must be limited to a permissible level. This is
achieved by using an inrush current limiting resistor in series to the capacitor. After
the charging of the capacitor is completed the limiting resistor is bridged, for example,
by a relay and is therefore only active at the switch-on of the inverter.
As the smoothing of the DC-link voltage requires a large capacity, the capacitor still
has a high voltage for some time after the disconnection of the inverter from the
mains.
The actual task of the frequency inverter, to produce an output voltage variable in
frequency and amplitude for the regulation/control of the three-phase AC motor, is
taken over by the converter at the output. It makes available a 3-phase output voltage
according to the principle of the pulse-width modulation, which generates a sinusoidal
current at the three-phase asynchronous motor
Mains rectifier
Motor
Converter
DC-link
Picture 2.1.2
Block diagram of an inverter power circuit
2.
Overview
Inkremental encoder imitation
Positioning control
Field orientated control
Synchron running
Automatic control adjusting