Siemens SINAMICS G110M - Motor Control; V;F Control

8.19 Motor control
Overview
The converter has two alternative methods to ensure the motor speed follows the con󹪝gured
speed setpoint:
• U/f control
• Vector control
8.19.1 V/f control
Overview
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In the "Flux Current Control (FCC)" U/f version, the converter controls the motor current (starting
current) at low speeds.
Figure 8-50 Simpli󹪝ed function diagram of the U/f control
The U/f control is a speed feedforward control with the following properties:
• The converter sets the output voltage on the basis of the U/f characteristic.
• The output frequency is essentially calculated from the speed setpoint and the number of
pole pairs of the motor.
• The slip compensation corrects the output frequency depending on the load and thus
increases the speed accuracy.
• The omission of a control loop means that the U/f control is stable in all cases.
• In applications with higher speed accuracy requirements, a load-dependent voltage boost
can be selected (󹪞ux current control, FCC)
For operation of the motor with U/f control, you must set at least the following subfunctions
appropriate for your application:
• U/f characteristic
• Voltage boost
Advanced commissioning
8.19 Motor control
Distributed converter for SIMOGEAR geared motors
Operating Instructions, 10/2020, FW V4.7 SP13, A5E31298649B AL 287