ABB ACSM1 - Page 53

Drive control and features
53
The figure below shows speed responses at a speed reference step (typically
1…20%).
The figure below is a simplified block diagram of the speed controller. The controller
output is the reference for the torque controller.
For more information on the use of the autotune function, see the description of
parameter 28.16 PI TUNE MODE.
A: Undercompensated
B: Normally tuned (autotuning)
C: Normally tuned (manually). Better dynamic performance than with B
D: Overcompensated speed controller
%
t
n
C
B
D
n
N
A
Derivative
Proportional,
integral
Derivative
acceleration
compensation
Torque
reference
Speed
reference
Actual speed
Error
value
-
+
+
+
+