KFU 2-/4-
212
16.5.6.1 Limitation
of
Modulation Controller
The output signal of the modulation controller is the internal reference flux. The con-
troller output and the integrating part are limited via the parameter
Reference Imr
lower limit
755
or the product of
Rated magnetizing current
716
and
Reference flux
717
. The magnetizing current parameter forming the upper limit is to be set to the
rated figure of the machine. For the lower limit, select a value which also builds up an
adequate flux in the machine in the field weakening area. The limitation of the control
deviation at the output of the modulation controller prevents a possible oscillation of
the control loop in the case of load surges. The parameter
Control deviation limita-
tion
756
is stated as an absolute value and acts both as a positive and a negative
limit.
Parameter
Settings
No.
Description
Min.
Max.
Fact. sett.
755 Reference Imr lower limit
0.01
I
FUN
ü
I
FUN
0.01
I
FUN
756 Control deviation limitation
0.00 %
100.00 %
10.00 %