Controller Adaptations - Baumuller b maXX BM3000 Operating Manual

4.7
Controllers
4.7.7

Controller adaptations

Several adaptations and compensations are available to the controller. Some can be set
in the parameter (controller adaptations-) mode Z155.1–. The status of the controller ad-
aptations are shown in the parameter (controller adaptations-) status Z155.2–.
In general the controller can operate without adaption (compensation) from the deviating
operating conditions of the operating point or from the deviating values of the data sheet.
An adaption makes the manual setting of the controller parameters easier and more reli-
able. On the other hand the adaption can improve the accuracy of some secondary vari-
able display parameters (such as the motor voltage) and the encoderless model-based
processes.
Linear functions are preferred.
Refer to the following listing of factors that effect the controller.
Field weakening effects
At asynchronous motors in the field weakening the "system gain" Ks drops when the mag-
netic flux falls and the electro-motoric force (EMF) of the motor (in contrast to the measure
point).
Temperature effects
If the motor temperature rises the electric resistance value in the motor increases.
At synchronous machines with permanent magnets an increase of the motor temperature
causes a reversible weakening of the magnetic force. This way a reversible drop of the
Kt-, Ke- and the Ks factors with the increasing motor temperature.
Saturation effects
In order to profit of the asynchronous motor normally the main inductance is brought to
the saturation point at the measuring point. In the field weakening with falling field current
the main inductance mainly originates from the saturation. Due to this the value of the
main inductance increases and therewith the ratio of magnetic flux and the magnetizing
current.
Generally, synchronous motors operate until standstill current lo in the linear range of the
torque current characteristic (or in the linear range of the Lq inductance, which means that
Lq is constant). The Lq inductance is nearly led to the saturation limit. The torque per
torque current and the Lq inductance drop similarly.
Load changing effects
If the load inertia torque changes considerably, then the actual "system gain" will strongly
differ from the used system gain (Ks factor Z18.40–) in the controller. At some applica-
tions the changes can be preassigned. The controller can be adjusted during operation.
Fabrication tolerances
The motor data can differ in contrast to the data sheet with regard to the fabrication. For
instance the Kt factor of the synchronous motor can differ about ±8% (contact the motor
manufacturer concerning this matter).
520 Parameter manual b maXX BM3000
Document no.: 5.12001.07
of 820
Baumüller Nürnberg GmbH