Siemens SINAMICS G110M - Sensorless Vector Control with Speed Controller; Structure of Vector Control Without Encoder (Sensorless)

8.19.2 Sensorless vector control with speed controller
8.19.2.1 Structure of vector control without encoder (sensorless)
Overview
The vector control comprises closed-loop current control and a higher-level closed-loop speed
control.
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1)
for induction motors
2)
Settings that are required
Figure 8-54 Simpli󹪝ed function diagram for sensorless vector control with speed controller
Using the motor model, the converter calculates the following closed-loop control signals from
the measured phase currents and the output voltage:
• Current component I
q
• Current component I
q
• Speed actual value
The setpoint of the current component I
d
(󹪞ux setpoint) is obtained from the motor data. For
speeds above the rated speed, the converter reduces the 󹪞ux setpoint along the 󹪝eld weakening
characteristic.
When the speed setpoint is increased, the speed controller responds with a higher setpoint for
current component I
q
(torque setpoint). The closed-loop control responds to a higher torque
setpoint by adding a higher slip frequency to the output frequency. The higher output frequency
also results in a higher motor slip, which is proportional to the accelerating torque. I
q
and
Advanced commissioning
8.19 Motor control
Distributed converter for SIMOGEAR geared motors
296 Operating Instructions, 10/2020, FW V4.7 SP13, A5E31298649B AL