Rockwell Automation 1407-CGCM Combination Generator Control Module - Manual (Page 186)

186 Rockwell Automation Publication 1407-UM001G-EN-P - April 2013
Appendix B CGCM Unit Math Models
Voltage Regulator The Per-unit Block Diagram for Rotating Rectifier Excitation System shows the
model of the CGCM excitation system 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
) to the CGCM 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 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)