Rockwell Automation 7000 PowerFlex Medium Voltage (B Frame) Commissioning - ForGe (PanelView 550) - Manual (Page 103)

Rockwell Automation Publication 7000-IN006B-EN-P - May 2013 99
Commissioning the Drive Chapter 5
Flux Regulator
Three parameters determine tuning for the flux regulator in an induction motor:
• FlxReg Bandwidth in Flux Control
• Lm Rated in Motor Model
• T Rotor in Motor Model
Set FlxReg Bandwidth to the default value of 10 r/s for almost all applications.
Lm Rated and T Rotor are usually unknown; measure them individually. 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,
determined by two parameters:
• Base Speed in Flux Control
• 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 normally operates at 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
Two parameters in the Speed Control group determine the speed regulator
tuning:
• SpdReg Bandwidth
• Total Inertia
Set Parameter SpdReg Bandwidth to a value determined by the requirements of
the application. Total Inertia is usually unknown; measure it separately. 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.
Load torque does not affect the inertia measurement as long as the drive does not
hit torque limit. Do not disconnect the driven load from the motor, you are
measuring the total inertia of motor and load.
Use the following procedure to auto-tune FluxSpeed Reg (Induction Motor):
1. Ensure that parameters Rated Motor RPM in Motor Ratings and L Total
Leakage in Motor Model have the correct value. Ensure that parameters
Autotune Spd Cmd and Autotune Trq Stp in Autotune use default values.
2. Set the Autotune Select parameter in Autotuning to FluxSpeed Reg.