Efficiency Optimization - Siemens SINAMICS S120 Function Manual

Operating Modes
Vector control
3.2.12

Efficiency optimization

Description
The following can be achieved when optimizing the efficiency using p1580:
S Lower motor losses in the partial load range
S Noise in the motor is minimized
Fig. 3-42
It only makes sense to activate this function if the dynamic response requirements
of the speed controller are low (e.g. pump and fan applications).
For p1580 = 100 %, the flux in the motor under no-load operating conditions is re-
duced to half of the setpoint (reference flux) (p1570/2). As soon as load is connec-
ted to the drive, the setpoint (reference) flux linearly increases with the load and at
approx. r0077 = r0331 * p1570 reaches the setpoint set in p1570.
In the field-weakening mode, the final value is reduced by the actual degree of field
weakening. The smoothing time (p1582) should be set to approx. 100 to 200 ms.
The flux differentiation (also refer to p1401.1) is automatically de-activated inter-
nally after magnetization.
Overview of important parameters (refer to the List Manual)
S r0077
S r0331
S p1570
S p1580
Function diagrams (refer to the List Manual)
S 6722
S 6723
3-154
f
set
p 1580
0 %
p1570
50 %
p1570*0.75
100 %
p1570*0.5
p1570*r0331/2
Efficiency optimization
CO: Current setpoints, torque-generating
Motor magnetizing current/short-circuit current (actual)
CO: Flux setpoint
Efficiency is optimization
Field weakening characteristic, Id setpoint (ASM, p0300 = 1)
Field weakening control, flux control for induction motors
(p0300 = 1)
i
(r 0077 )
qset
p1570*r0331
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition