Siemens SINAMICS G120 Operating Instructions Manual page 355

Efficiency optimization, method 2
Generally, energy efficiency optimization method 2 achieves a better efficiency than method 1.
We recommend that you set method 2.
Figure 6-76
Based on its thermal motor model, the inverter continually determines - for the actual operating
point of the motor - the interdependency between efficiency and flux. The inverter then sets
the flux to achieve the optimum efficiency.
Figure 6-77
Depending on the motor operating point, the inverter either decreases or increases the flux in
partial load operation of the motor.
Efficiency optimization, method 1
Figure 6-78
Converter with the CU250S-2 Control Units
Operating Instructions, 04/2018, FW V4.7 SP10, A5E31759476B AG
Determining the optimum flux from the motor thermal model
Qualitative result of efficiency optimization, method 2
Reduce the flux setpoint in the partial load range of the motor
Advanced commissioning
6.32 Efficiency optimization
353