Rockwell Automation Allen-Bradley PowerFlex 755T Flux Vector Tuning - Page 43

Rockwell Automation Publication 750-AT006D-EN-P - January 2022 43
Chapter 2 Product Features
Gain Stabilization is good for situations where there are more resonances than there are notch filters and for keeping the drive stable.
Instability and audible noise are caused from the following situations:
• HF resonances that are not already suppressed by filters
• MF resonances that are suppressed by filters but the filter bandwidths are too close to the closed loop bandwidth
• LF resonances that result when load observer is not applied with the recommended out-of-box settings
• LF resonances that result from classical instability
Figure 42 - Identifying One LF Resonance
Other considerations:
• Adaptive tuning Gain Stabilization is not recommended for vertical loads as detuning can cause load drops.
Tracking Notch and Gain Stabilization
10:2110 [AdptTune Config] = TrkNFGainStb (3) – In this mode, adaptive tuning applies the Tracking Notch function if necessary, followed by
Gain Stabilization function if necessary. Parts of the control loop structure affected by this mode are highlighted in Figure 43.
Figure 43 - Tracking Notch Filter and Gain Stabilization Configuration
First, the adaptive tuning Tracking Notch function sets the actual torque notch filter parameters to suppress HF resonances if they exist.
Next, the adaptive tuning Gain Stabilization function sets the actual torque low pass filter parameters to suppress additional HF resonances
if they exist. This is useful for suppressing more HF resonances than there are notch filters.
2
1
sJ
T
PI
s
PI
s
Fs
K
T
P
REG
V
REG
Velocity
Feedback
Filter
Position
Feedback
Velocity
Estimate
Feed
Forwards
Kvff Kaff
Position
Command
LP
LL
N
Torque Loop Filters
Load Torque
Load
Observer
K
J
Torque
Estimate
Adaptive
Tuning
RN
System Under Control
P
REF