Lenze i510 - Oscillation Damping

7.3.5 Oscillaon damping
The oscillaon damping serves to r
educe the oscillaons during no-load operaon which are
caused by energy oscillang between the mechanical system (mass inera) and the electrical
system (DC bus). Furthermore, the oscillaon damping can also be used to compensate for
resonances.
Precondions
"V/f characterisc control (VFC open loop)" motor control has been selected in 0x2C00
(PAR 300). Otherwise the oscillaon damping is not eecve.
Restricons
Observe the following restricons:
•
Damping is possible only for constan
t oscillaons at a steady-state operang point.
•
Oscillaons occurring sporadically cannot be damped.
•
Oscillaon damping is not suitable for oscillaons occurring during dynamic processes (e.
g.
acceleraons or load changes).
•
Oscillaon damping is only acve if the setpoint speed is greater than 10 rpm and the DC-
bus voltage exceeds a value of 100 V.
Details
The determinaon of the oscillaon is based on the acve current. In order to obtain the
alternang component of the acve current, this current is dierenated. This signal is then
passed through a PT1 lter.
Idencaon of the oscillaon
Before the oscillaon damping funcon can be parameterised, the oscillaon has to be iden-
ed. One way to do this is to examine the motor current while oscillaon damping is switched
o (gain = 0 %). At steady-state operaon, a constant current ows. If the drive oscillates,
these oscillaons are also visible on the motor current. It is therefore possible to determine
the frequency and the amplitude of the oscillaon from the alternang component of the
motor current. In the following, this alternang component is referred to as "current oscilla-
on".
Parameter seng
The gain of the oscillaon signal is to be set according to the following equaon:
0x2B0A:001 (PAR 318/001) = current amplitude * 100 % / (Ö2 * ma
ximum device current)
The default me constant of the PT1 lter should be sucient for most applicaons. If
required, it is only possible to adapt the me constant via »EASY Starter«. Generally, the me
constant must be set so that the oscillaon can be dampened, but that higher-frequency com-
ponents are ltered from the signal. The me constant is determined from the reciprocal
value of the double current oscillaon frequency:
0x2B0A:002 (PAR 318/002) = 1 / (2 * oscillaon frequency)
Parameter Name / value range / [default seng] Info
0x2B0A:001
(PAR 318/001)
Oscillaon damping: Gain
(Oscillaon damping
: Oscillaon: gain)
-100 ... [20] ... 100 %
Gain of the oscillaon signal.
•
With the seng 0, oscillaon damping is deacvated.
0x2B0A:002
(PAR 318/002)
Oscillaon damping: Filter me
(Oscillaon damping: Oscillaon: me)
1 ... [5] ... 600 ms
Time constant of the PT1 lter.
0x2DDF:002 Axis informaon: Maximum current
•
Read only: x.xx A
•
Default seng depending on the size.
Display of the maximum current of the axis.
0x2D88
(PAR 104)
Actual motor current
(Act. motor current)
•
Read only: x.x A
Display des present current-r.m.s. value.
Motor control
Opmisaon of motor control
Oscillaon damping
88
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