Closed-Loop Speed Control - Siemens SINAMICS G120 Operating Instructions Manual

Setting functions
8.5 Motor control
8.5.2

Closed-loop speed control

Sensorless vector control
Using a motor model, the speed control calculates the load and the motor slip. As a result of
this calculation, the inverter controls its output voltage and frequency so that the motor
speed follows the setpoint, independent of the motor load.
Speed control is possible without directly measuring the motor speed and is therefore also
called "sensorless vector control".
Figure 8-21 Simplified function diagram of sensorless vector control
You can find additional information on speed control in the function diagrams 6020 ff. of the
List Manual.
Vector control with encoder
Instead of the calculated speed from the motor model, the vector control with encoder
evaluates an encoder.
248
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB