ABB DCS 500B

Functional Software description
DCS 500 Software Description 63
erroneous result.
The limit at which the I-part is released can be defined by parame-
ter:
EMF REL LEV (1011) default value is 50
(100 * 50/3786 = 1.3%)
EMF-error value
filter
The EMF actual value can be filtered for the controller by means of
1st order filter. The time constant of the filter can be given by pa-
rameter
EMF FILT TC (513) scaling 1000 = 1s
(0...10000)
PI -gain value
scaling
P-gain of the controller is reduced above the field weakening point
by the factor 1/n in order to keep the process gain constant. P-gain
can be adjusted by means of parameter
EMF KP (1007) Scaling is internal unit
277 = 100 %
(1...999)
I-time constant does not have 1/n scaling factor, and it is separated
from the P-gain value. Time constant = 147200 / EMF KI and it can
be adjusted by means of parameter
EMF KI (1008) Scaling is internal unit
20000 = 7.4 ms
PI - controller
output limitation
The output of the PI-controller is limited so that 100% of final FLUX
reference is the absolute maximum value. The positive level of the
PI-controller is limited so that at exactly the field weakening point
the positive limit is zero. Above the field weakening point the posi-
tive limit starts to increase to facilitate a smooth transfer to the field
weakening area.
Limits for the PI-controller can be adjusted by means of parameters
EMF REG LIM P (1009) 4095 = nominal FLUX
+410 = default (+10%)
EMF REG LIM N (1010) -4095 = -nominal FLUX = def.