Lenze 8400 - Manual (Page 240)

5 Motor control (MCTRL)
5.9 Servo control (SC)
240
Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
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Field feedforward control
To have enough voltage reserve available for dynamic acceleration processes, a timely weakening
of the field is required. The field weakening is controlled by the field feedforward control.
The field feedforward control reciprocally reduces the magnetising current from the V/f base
frequency ( C00015 ) on. The starting point of the reduction can be shifted to low frequencies via the
field feedforward control ( C00576 ). Thus, more voltage reserve is available for acceleration
processes.
The field feedforward control (
C00576 ) must be specified in %, based on the rated slip of the
machine.

Tip!
Generally, the Lenze setting is sufficient for most applications.
• We recommend to increase the field feedforward control for applications with very
dynamic acceleration processes in the field weakening range.
• Reduce the field feedforward control for very slow applications if necessary.
Adaptive adaptation of the P component of the field and speed controllers
In the field weakening range, the properties of the drive change due to the reduction of the
magnetisation and the voltage limitation of the inverter. To be able to continue to provide a stable,
well dampened drive behaviour, the servo control has an automatic adaptation of the P component
of the field weakening controller and speed controller.
In the Lenze setting, this function is activated. Depending on the application, this function can be
deactivated via C00079/2 .

Tip!
Lenze recommends to always activate the adaptation of the field weakening and speed
controller.
Parameter Info Lenze setting
Value Unit
C00576 SC: Field feedforward control 200.0 %
Parameter Info Lenze setting
C00079/2 SC: Adaptive field weakening controller 1: On