However, in all applications, speed and torque are specified by the driven machine. As a
consequence, the remaining variable for the efficiency optimization is the flux.
The converter has two different methods of optimizing the efficiency.
Efficiency optimization, method 2
Generally, energy efficiency optimization method 2 achieves a better efficiency than method 1.
We recommend that you set method 2.
,QYHUWHU
7KHUPDOPRWRU
PRGHO
(IILFLHQF\
GHSHQGHQWRQWKH
IOX[
2SWLPXPIOX[
Figure 6-93
Determining the optimum flux from the motor thermal model
Based on its thermal motor model, the converter continually determines - for the actual
operating point of the motor - the interdependency between efficiency and flux. The converter
then sets the flux to achieve the optimum efficiency.
)OX[
(IILFLHQF\
)OX[
(IILFLHQF\
(IILFLHQF\RSWLPL]DWLRQLVQRWDFWLYH
(IILFLHQF\RSWLPL]DWLRQLVDFWLYH
Figure 6-94
Qualitative result of efficiency optimization, method 2
Depending on the motor operating point, the converter either decreases or increases the flux
in partial load operation of the motor.
Advanced commissioning
6.10 Energy saving
SINAMICS G120X converter
Operating Instructions, 06/2019, FW V1.01, A5E44751209B AC
435
