Moment Of Inertia Estimator - Siemens SINAMICS G120C Operating Instructions Manual

Advanced commissioning
6.5 Motor control
6.5.2.3

Moment of inertia estimator

Background
From the load moment of inertia and the speed setpoint change, the inverter calculates the
accelerating torque required for the motor. Via the speed controller precontrol, the
accelerating torque specifies the main percentage of the torque setpoint. The speed
controller corrects inaccuracies in the precontrol (feed-forward control).
Figure 6-36
The more precise the value of the moment of inertia in the inverter, the lower the overshoot
after speed changes.
Figure 6-37
Function
From the actual speed, the actual motor torque and the frictional torque of the load, the
inverter calculates the total moment of inertia of the load and motor.
Figure 6-38
208
Influence of the moment of inertia estimator on the speed control
Influence of the moment of inertia estimator on the speed
Overview of the function of the moment of inertia estimator
Operating Instructions, 07/2015, FW V4.7 SP3, A5E34263257B AC
SINAMICS G120C converter