2.5 PID Control
2.5.1 Speed PID Control
Parameter 1-00 Configuration Mode
Parameter 1-01 Motor Control Principle
U/f
VVC
+
[1] Speed closed loop
Not available
1)
Active
Table 2.5 Control Configurations, Active Speed Control
1) Not available indicates that the specific mode is not available at all.
The following parameters are relevant for the speed control:
Parameter
Description of function
Parameter 7-00 Speed PID Feedback Source
Select from which input the speed PID gets its feedback.
Parameter 7-02 Speed PID Proportional Gain
The higher the value, the quicker the control. However, too high a value may lead to
oscillations.
Parameter 7-03 Speed PID Integral Time
Eliminates steady state speed error. Lower values mean quicker reaction. However, too low
a value may lead to oscillations.
Parameter 7-04 Speed PID Differentiation Time
Provides a gain proportional to the rate of change of the feedback. A setting of 0 disables
the differentiator.
Parameter 7-05 Speed PID Diff. Gain Limit
If there are quick changes in reference or feedback in a given application, which means
that the error changes swiftly, the differentiator may soon become too dominant. This is
because it reacts to changes in the error. The quicker the error changes, the stronger the
differentiator gain is. The differentiator gain can thus be limited to allow setting of the
reasonable differentiation time for slow changes and a suitably quick gain for quick
changes.
Parameter 7-06 Speed PID Lowpass Filter Time
A low-pass filter that dampens oscillations on the feedback signal and improves steady
state performance. However, too long a filter time deteriorates the dynamic performance of
the speed PID control.
Practical settings of
parameter 7-06 Speed PID Lowpass Filter Time
taken from the number of
pulses per revolution on from encoder (PPR):
Encoder PPR
Parameter 7-06 Speed PID Lowpass Filter
Time
512
10 ms
1024
5 ms
2048
2 ms
4096
1 ms
Table 2.6 Speed Control Parameters
Product Overview
Design Guide
MG07B102
Danfoss A/S © 03/2016 All rights reserved.
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