Extended Torque Control" Function Module (Kt Estimator) - Siemens SINAMICS S120 Function Manual

Operating Modes
Servo control
3.1.6 "Extended torque control" function module (k
Description
The function module "extended torque control" comprises two modules – the k
estimator and the compensation of the voltage emulation error of the drive con-
verter. This allows the torque accuracy to be increased.
Note
When this function module is activated, the maximum number of drives that can
be controlled from a control unit is reduced by at least one drive.
Features
S k
estimator (only for synchronous motors)
T
S Compensation of the voltage emulation error of the drive converter
(p1952, p1953)
S Configuration via p1780
Commissioning via STARTER
The extended torque control can be activated via: Righthand mouse click on the
drive –> Properties –> Function modules.
Parameter r0108.1 indicates whether it has been activated.
Description k estimator
T
The adaptation of the torque constants for synchronous motors is used to improve
the absolute torque accuracy for the control (closed-loop) of synchronous motors.
The magnetization of the permanent magnets varies as a result of production tole-
rances and temperature fluctuations and saturation effects. This function "k
mator" adapts the torque constant k
magnetization. It only makes sense to use the k
friction characteristic as the k
The frictional losses must be compensated from the friction characteristic using a
supplementary torque.
The k estimator requires the most accurate values for the motor parameters as
T
possible in order to achieve a high torque accuracy. Before using the k
it is therefore necessary to carry-out a motor identification routine (p1909, p1910)
with the k
T
(p0350), leakage inductance (p0356) and voltage emulation errors (p1952, p1953).
The cable resistance must be calculated before the motor identification and ent-
ered into p0352.
3-80
estimator can only correct the inner motor torque.
T
estimator activated; this determines the values for the stator resistance
[Nm/A] in the control to the instantaneous
T
estimator in conjunction with the
T
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
estimator)
T
T
esti-
T
estimator,
T