Rockwell Automation Publication 7000L-UM301F-EN-P - March 2020
245
Commissioning
Chapter 4
3.
T Rotor in Motor Model
FlxReg Bandwidth
should be set to the default value of 10 r/s for almost all
applications.
Lm Rated
and
T Rotor
are usually unknown and must be measured.
Both of these motor parameters change substantially with different operating
conditions, but the variations do not significantly affect the operation of the flux
regulator.
The other aspect of flux control is the variation of motor flux with speed. This is
determined by two parameters:
1.
Base Speed
in
Flux Control
2.
FlxCmd RatedLoad
in
Flux Control
In most applications, the motor runs at constant flux below rated speed and
constant voltage above rated speed. The motor flux is normally set to a level that
provides rated voltage at rated speed and full load. The flux level required to
achieve this is a function of the motor parameters. The flux regulator auto-tuning
determines a value of rotor flux that should provide rated motor voltage at full
load and rated speed, and sets the flux command parameter to this value.
Speed Regulator
The tuning of the speed regulator is determined by two parameters in the
Speed
Control
group:
1.
SpdReg Bandwidth
2.
Total Inertia
Parameter
SpdReg Bandwidth
is set to a value determined by the requirements of
the application, but parameter
Total Inertia
is usually unknown and must be
measured. The auto-tuning determines the total inertia by measuring the change
in speed that occurs when a low frequency sinusoidal torque perturbation is
applied to the motor. The inertia measurement is not affected by the load torque
as long as the drive does not hit torque limit. Do not disconnect the driven load
from the motor, as it is the total inertia of motor and load that is being measured.
FluxSpeed Reg Auto-tuning [Induction Motor]
The following procedure should be used to perform FluxSpeed Reg auto-tuning:
1.
Ensure that parameters
Rated Motor RPM
in
Motor Ratings
and
L Total Leakage
in
Motor Model
are set to the correct value. Ensure that
parameters
Autotune Spd Cmd
and
Autotune Trq Stp
in
Autotune
are set to
default values.
2.
Set parameter
Autotune Select
in
Autotuning
to
FluxSpeed Reg
.
