Sensorless Vector Control With Speed Controller; Structure Of Vector Control Without Encoder (Sensorless) - Siemens SINAMICS G115D Operating Instructions Manual

Advanced commissioning
6.18 Motor control
6.18.2

Sensorless vector control with speed controller

6.18.2.1

Structure of vector control without encoder (sensorless)

Overview
The vector control comprises closed-loop current control and a higher-level closed-loop speed
control.
for asynchronous motors
1 )
Settings that are required
2 )
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
• Current component I
• Speed actual value
The setpoint of the current component I
speeds above the rated speed, the converter reduces the flux setpoint along the field
weakening characteristic.
When the speed setpoint is increased, the speed controller responds with a higher setpoint
for current component I
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 and I
q
matching current component I
260
q
d
(torque setpoint). The closed-loop control responds to a higher
q
controllers keep the motor flux constant using the output voltage, and adjust the
d
(flux setpoint) is obtained from the motor data. For
d
in the motor.
q
Operating Instructions, 12/2020, FW V4.7 SP13, A5E48681219B-002
SINAMICS G115D distributed drive