5motor interface – Lenze 9400 User Manual
Page 192
5
Motor interface
5.6
V/f control (VFCplus)
192
Lenze · Servo-Inverter 9400 HighLine · Reference manual · DMS 10.0 EN · 11/2013 · TD05/06
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Identification of the oscillation
Before the oscillation damping can be parameterised, the oscillation has to be identified. One way
is to examine the motor current while oscillation damping is switched off (
= 0 %). At steady-
state operation, a constant current flows. If the drive oscillates, these oscillations are also visible on
the motor current. It is therefore possible to determine the frequency and the amplitude of the
oscillation from the alternating component of the motor current. In the following, this alternating
component is referred to as "current oscillation".
Parameter setting
• The time constant (
) is determined from the reciprocal value of twice the frequency of
the current oscillation:
• The gain factor (
) is calculated with the following formula based on the relationship
between the amplitude of the current oscillation and the maximum device current:
• The maximum oscillation frequency (
) serves to the absolute limitation of the oscillation
frequency calculated before it is added to the field frequency. It can be derived from the
amplitude of the current oscillation, the rated motor current, and the slip frequency of the
motor connected:
•
From software version V5.0:
The ramp end frequency (
) defines the rotational frequency
from which the gain factor is to have reached its nominal value (
• The ramp end frequency refers to the rated motor frequency in percent (
).
• Below a speed of 10 rpm, the oscillation damping remains deactivated.
• For machines with a power greater than 55 kW a ramp end frequency of 20 % is
recommended.
Short overview: Parameters for oscillation damping
Parameter
Info
Lenze setting
Value Unit
VFC: Gain - oscillation damping
20 %
VFC: Time const. - oscill. damp.
5 ms
VFC: Limitation - oscillation damping
0.2 Hz
VFC: Ramp end freq. - oscillation damping
0 %
Time constant
1
2 Oscillation frequency
⋅
--------------------------------------------------------------
=
Gain
Current amplitude
2 Maximum device current (C00789)
⋅
------------------------------------------------------------------------------------------------------
100 %
⋅
=
Max. frequency
2 Amplitude of the current oscillation
⋅
Rated motor current
----------------------------------------------------------------------------------------------------
Rated slip frequency
⋅
=