Flux-Feed Forward; Parameters For Flux Feed-Forward - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

Advanced Operating Functions

8.7 Flux-Feed Forward

8.7 Flux-Feed Forward
8.7.1

Parameters for Flux Feed-Forward

Parameters for Flux Feed-Forward
Refer to Motor Parameter Menu (1000) in Section Options for Motor Menu (1) of
Chapter Parameter Assignments / Addressing for parameters associated with this function:
• Leakage inductance (1070)
• Saliency constant (1091)
8.7.2 Flux Feed-Forward
Flux feed-forward is a compensation input to increase performance of the flux loop. It works in
the following way:
1. The flux reference is preset to the no-load flux command when enabled. This eliminates a
delay in the response of the flux loop that would occur if starting from zero.
2. Next, the flux based on the load is compensated by feeding a reference proportional to the
torque command to the output of the flux regulator.
This compensates for the reduction of flux resulting from interaction with the torque current,
increasing the I
The functionality of flux feed-forward is essentially the same for both induction motors (IM) and
synchronous motors (SM). The difference between the motor types is as follows:
• IM: compensate for leakage inductance losses only using parameter Leakage inductance
(1070) to affect the amount of compensation.
• SM: compensate for the leakage inductance and a part of the mutual inductance, using
parameter Saliency constant (1091). This parameter applies only to SM control, and is used
instead of the leakage inductance parameter. Zeroing the saliency constant still provides the
no load feed-forward term, which essentially provides the no load flux reference. The
saliency constant provides additional compensation for the inductance losses due to
fluctuations of torque current for which the flux regulator may be too slow to correct. Setting
it too high can cause the motor flux to be too high resulting in motor over-voltage or
saturation.
240
(reactive) current as a linear function of I
d
(torque) current.
q
NXGPro+ Control Manual
Operating Manual, A5E50491925A