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Rockwell Automation Publication 1407-UM002B-EN-P - February 2019
Appendix B
CGCM-DLR Unit Math Models
Voltage Regulator
Per-unit Block Diagram for Rotating Rectifier Excitation System
shows the
model of the CGCM-DLR excitation system that is used with a brush-type
rotating exciter.
The rotating exciter parameters are not included in this discussion because they
are the responsibility of the exciter manufacturer. V
P
is the input from the power
source for the excitation system.
A typical value for T
A
is 0. The forcing limit V
RLMT
is related to the power-input
voltage (V
P
) and the exciter field voltage (V
R
) as follows:
V
RLMT
= 1.4*V
P
/ V
R
The gain K
G
is used for compensating variations in system configuration such as
power input voltage. The per unit base of the parameters V
P
and V
R
is the
nominal exciter field voltage at no load.
The PID gains K
P
, K
I
, and K
D
are custom designed for the best performance for
each generator/exciter system. These continuous time gains are changed to
discrete and implemented in the CGCM-DLR digital controller. The PID gains
can be obtained from the PID Calculator software available from Rockwell
Automation.
Figure 60 - Per-unit Block Diagram for Rotating Rectifier Excitation System
V
RLMT
/(V
p
0.005)
-V
RLMT
/(V
p
0.005)