Rockwell Automation Allen-Bradley PowerFlex 755T Flux Vector Tuning User Manual

56 Rockwell Automation Publication 750-AT006D-EN-P - January 2022
Chapter 3 Out-of-Box Tuning
To increase damping when K
VP
is artificially lowered, different methods are applied based on the load observer mode:
• Load Observer Disabled
on page 56
• Load Observer Only or Acceleration Feedback on page 56
• Velocity Estimate Only on page 57
• Load Observer with Velocity Estimate on page 57
Load Observer Disabled
When 10:901 [Load Ratio] = 0 and 10:2020 [LdObs Mode] = Disabled (0), the position loop gains decrease by an additional factor of 10. This
reduction increases the loop spacing to allow enough room for K
VP
when it is artificially lowered. K
VI
does not decrease by an additional
factor of 10 because it provides improved stiffness without the risk of instability. The default damping factor is Z = 1, which produces a loop
spacing of 4Z
2
= 4.
Figure 56 - Out-of-Box Gain Relationships for Load Observer Disabled
Load Observer Only or Acceleration Feedback
When 10:901 [Load Ratio] = 0 and 10:2020 [LdObs Mode] = LdObs Only (1) or 10:2020 [LdObs Mode] = Accel Fdbk (4), there is no need to
decrease the position loop gains by an additional factor of 10 because the load observer accounts for the unknown load to maintain that K
VP
is not artificially lowered. Also, K
VI
is disabled because the load observer operates as a good velocity integrator. Load Observer Only mode is
recommended for velocity control applications.
Table 20 - Variables for Increasing Damping
Bandwidth Abbreviation Parameter No. Parameter Name Description Units
T
BW
— — Torque Loop Bandwidth Hz
Z 10:907 [System Damping] System Damping —
K
PP
10:1754 [c PReg Kp] Position Loop Bandwidth Hz
K
PI
10:1756 [c PReg Ki] Position Integrator Bandwidth Hz
K
VP
10:1955 [c VReg Kp] Velocity Loop Bandwidth Hz
K
VI
10:1957 [c VReg Ki] Velocity Integrator Bandwidth Hz
K
OP
10:2021 [c LdObs Kp] Load Observer Bandwidth Hz
K
OI
10:2023 [c LdObs Ki] Load Observer Integrator Bandwidth Hz
LPF 10:2154 [c Trq LPF BW] Torque Low Pass Filter Bandwidth —
0
K
PI
K
PP
K
VP
K
VI
2
4
1
Z
1
2
40
1
Z
K
OP
K
OI
0
LPF
5
System
BW
1
T
BW
2
4
1
Z
2 Hz
(Open Loop
Virtual Encoder)

Rockwell Automation Allen-Bradley PowerFlex 755T Flux Vector Tuning Specifications

General

Brand	Rockwell Automation
Model	Allen-Bradley PowerFlex 755T Flux Vector Tuning
Category	Industrial Equipment
Language	English