Torque Generation; Armature Voltage Control; Fiel Current Control; Armature Current Control - ABB DCS 600 Manual
Dcs thyristor power converters
for dc drive systems
25 to 5150 a
6 to 4900 kw
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Also See for DCS 600:
- Operating instructions manual (80 pages) ,
- Manual (62 pages) ,
- Service manual (126 pages)
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3.6 Torque Generation
Interface between SDCS-AMC-DC board and DC
control board SDCS-CON-2
The major signals exchanged each 2 ms between
the CON-2 and the AMC-DC board are:
SPEED_ACTUAL
speed actual value from
CON-2
TORQ_USED_REF
active torque reference to
CON-2
In addition, the calculated torque limits from the
CON-2 are read from the CON-2 each 8 ms:
TC_TORQMAX
TC_TORQMIN
The addition of the torque correction TQ_CORR
from an analogue input of CON-2 is done by the
CON-2 software.
Armature voltage Control
This controller enables operation in the field
weakening range. It outputs the field current
reference. At low speed the field current is
constant and armature voltage is roughly propor-
tional to the speed. At higher speed the field
current reference is reduced so that the armature
voltage doesn’t exceed its reference.
Field Current Control
Two field exciters can be operated simultaneous-
ly for two different motors.
The second field exciter has a fixed current
reference. However, it may be reduced for field
heating purposes.
The first field exciter can be operated with fixed
current reference, the output of the armature
voltage controller (field weakening) or with a
reduced reference for field heating.
A field reversal control is available for the first
field exciter. This is needed in case of a four
quadrant drive with a single direction armature
converter.
Optitorque is a special control method where the
flux is reduced at small torque reference. This is
available for drives with and without field revers-
al.
Armature Current Control
The armature current reference is calculated from
torque reference and flux. Then it is processed by
a ramp, limitation and speed dependent limita-
tion.
The actual value of the armature current is the
measured mean value between two firing pulses.
The armature voltage reference is generated by a
PI controller.
The firing angle is calculated from this voltage
reference depending on the actual line voltage
and the conduction time (adaptation between
continuous and discontinuous state of the con-
verter current).
A simplified scheme of the armature current
control is given in diagram fig. 3.7/3.
II F 3-5
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