2 oscillation damping in the field weakening range, Oscillation damping in the field weakening range, 5motor control (mctrl) – Lenze 8400 StateLine User Manual
Page 218
5
Motor control (MCTRL)
5.9
Parameterisable additional functions
218
Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
5.9.6.2
Oscillation damping in the field weakening range
When the max. possible output voltage (full modulation) has been reached, a voltage dip in the DC
bus causes a voltage fluctuation in the motor. With load and during no-load operation this voltage
fluctuation can cause mechanical oscillations.
The "oscillation damping field weakening" adjustable in
serves to limit the maximum
output voltage. This can be used to always compensate voltage dips in the DC bus to the output
voltage (constant output voltage). This serves to prevent mechanical oscillations due to these
voltage dips.
the limitation of the output voltage is set so that voltage dips
in the DC bus in the output voltage for the single-phase and three-phase devices can largely be
compensated so that no speed oscillations may be expected. Thus, an adaptation of
not required in the majority of cases.
• Maximum output voltage to be reached with Lenze setting of
• Single-phase devices: 98.2 %
• Three-phase devices: 99.7 %
How to eliminate speed oscillations in the field weakening range:
1. Approach the area where the speed oscillations occur.
2. Reduce the speed oscillations by changing
step by step (increment 1).
3. These can be indicators for smooth running:
• Constant motor current characteristic
• Reduction of the mechanical oscillations in the bearing seat
Parameter
Info
Lenze setting
Value Unit
Oscillation damping field weakening
• Setting "0" ≡ 100 % output voltage can be reached
14
Note!
The limitation of the output voltage via
in the extreme field weakening range
(high speeds) causes a reduction of the max. possible output torque (stalling torque).
• If the output torque to be reached in the extreme field weakening range is not
sufficient (motor is stalling too early), reduce the setting in
.