Danfoss VLT AQUA Drive Design Manual page 28

2. Introduction to the VLT AQUA Drive
4.
2
Type of Control
PI-control
PID tight control
PID some overshoot
Ziegler Nichols tuning for regulator, based on a stability boundary.
Experience has shown that the control setting according to the Ziegler Nichols rule provides a
good closed-loop response for many systems. If necessary, the operator can perform the final
tuning of the control iteratively in order to modify the response of the control loop.
28
NOTE: P should be measured when the amplitude of oscillation is relatively small. The
u
output must not saturate (i.e., the maximum or minimum feedback signal must not be
reached during the test).
Use the table below to calculate the necessary PID control parameters.
Proportional Gain
K
0.45 *
u
K
0.6 *
u
0.33 * K
u
MG.20.N2.22 - VLT
Integral Time Differentiation
Time
P
0.833 * -
u
P
0.5 * 0.125 *
u
0.5 * P 0.33 *
u
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VLT ® AQUA Drive Design Guide
P
u
P
u