Siemens SINAMICS G115D Operating Instructions Manual page 337

Active efficiency optimization has the following advantages:
• Lower energy costs
• Lower motor temperature rise
• Lower motor noise levels
Active efficiency optimization has the following disadvantage:
• Longer acceleration times and more significant speed dips during torque surges.
The disadvantage is only relevant when the motor must satisfy high requirements relating
to the dynamic performance. Even when efficiency optimization is active, the converter
closed-loop motor control prevents the motor from stalling.
Precondition
Efficiency optimization functions under the following preconditions:
• Operation with an asynchronous motor
• Vector control is set in the converter.
Function description
The three variables that the converter can directly set, which define efficiency of an
asynchronous motor, are speed, torque and flux.
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.
SINAMICS G115D Wall Mounted distributed drive
Operating Instructions, 07/2023, FW V4.7 SP14, A5E52808211A AA
Advanced commissioning
7.28 Efficiency optimization
335