Sensorless Vector Control With Speed Controller; Overview - Siemens SINAMICS G120 Operating Instructions Manual

6.18.3

Sensorless vector control with speed controller

6.18.3.1

Overview

Overview
The vector control comprises closed-loop current control and a higher-level closed-loop speed
control.
For induction motors
1)
Figure 6-48 Simplified function diagram for sensorless vector control with speed controller
All of the function block diagrams 6020 ff. for vector control are provided in the List Manual:
Using the motor model, the inverter calculates the following closed-loop control signals from
the measured phase currents and the output voltage:
● Current component I
● Current component I
● Speed actual value
The setpoint of the current component I
speeds above the rated speed, the inverter reduces the flux setpoint along the field weakening
characteristic.
When the speed setpoint is increased, the speed controller responds with a higher setpoint
for the current component I
torque setpoint by adding a higher slip frequency to the output frequency. Also in the motor,
the higher output frequency results in a higher slip, which is proportional to the accelerating
Converter with the CU240B-2 and CU240E-2 Control Units
Operating Instructions, 01/2017, FW V4.7 SP6, A5E34259001B AD
d
q
(flux setpoint) is obtained from the motor data. For
d
(torque setpoint). The closed-loop control responds to a higher
q
Advanced commissioning
6.18 Motor control
285