Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 133

Adjustable Flux Demand
Note
This feature is currently not implemented in NXGPro+
Some motors require less flux at startup to prevent saturation, some applications require
increased torque at start or low speed and hence a higher than rated flux to start. Another
possibility is increasing flux below base speed of a motor to allow higher torque up to rated
speed with the motor achieving full voltage at less than rated speed – essentially changing the
Volts/Hz slope of the flux.
By utilizing fixed speed points that are distributed with a higher concentration in the lower speed
regions, a flux table can be created to address all these needs. The user sets the flux at each
speed setpoint to create the desired starting curve.
Each of 12 speed setpoints are identified in the menu as "Flux @ xx% spd" in PU flux demand. The
range is from 0.0% (0.0) to 40% (0.4) with the default flux set to 1.0 at each setpoint. The 13th
speed setpoint is at 50% and is set by the original parameter "Flux Demand" (3150). Refer to
table Flux Table Menu (3131) Parameters.
When enabled by the parameter "Flux Table Enable" (3132), the flux demand it set by the flux
demand at each speed setpoint and linear interpolation is used to address points in between.
'On use' is for reduced flux on startup. The table will extend in the lower speed regions up to 50%
speed. There are no additional flux table entries above this point. See figure Flux Reduction.
1.2
1
0.8
0.6
0.4
0.2
0
Figure 6-3
For some applications, a flux boost rather than flux weakening is desired. See figure Flux Boost.
NXGPro+ Control Manual
Operating Manual, A5E50491925A
0 7 14 21 28 35 42 49 56 63 70 77 84 91 98
Flux Reductiom
6.8 Options for Stability Menu (3) - first half
Flux Reduc on
Parameter Assignment/Addressing
Flux in PU
131