Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 295)

4-90 Commissioning
7000L-UM300I-EN-P – June 2013 7000 “C” Frame
Tuning the Flux Regulator
The tuning of the flux regulator for a synchronous machine is
determined by four parameters:
1. Flxreg Bandwidth in "Flux Control"
2. L magnetizing in "Motor Model"
3. T rotor in "Motor Model"
4. Lmd in “Motor Model”
"Flux Regulator Bandwidth" should be set to the default value for
almost all applications. "L magnetizing", “Lmd”, and "T rotor" are
usually unknown and must be measured. Although these motor
parameters change with different operating conditions, 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. Flux Command Base Speed in "Flux Command"
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 autotuning 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.
Flux Regulator Autotuning
Note: If a position encoder is fitted to the motor, the flux regulator
autotuning is performed with the encoder feedback turned off because
it is assumed that the encoder has not been aligned with the rotor axis
yet. Since less starting torque is produced with the encoder feedback
off, this test should be performed with reduced load. The encoder
offset measurement is also most accurate with no load on the motor.
The flux regulator is tuned with the motor running at constant speed
using the following procedure:
1. Ensure that the analog reference for the field current has been set
up as described previously, and that parameter “L total leakage”
has been set to the correct value.
2. Set parameter "Autotune Select" in "Autotuning" to “Flux Reg”.