Lenze i410 - Set Oscillation Damping

9.2.6 Set
oscillaon damping
The oscillaon damping serves to reduce 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
The funcon is only eecve in the motor control type "V/f characterisc control (VFC open
loop)".
Restricons
Observe the following restricons:
•
Damping is possible only f
or constant 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
Set the gain of the oscillaon signal according to the following equaon:
0x2B0A:001 (P318.01) = current amplitude * 100 % / (Ö
2
* maximum device current)
The default me constant of the PT1 lter is 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 is dampened and higher-frequency components are ltered from
the signal. The me constant is given by the reciprocal value of double the current oscillaon
frequency:
0x2B0A:002 (P318.02) = 1 / (2 * oscillaon frequency)
Parameter
Address Name / seng range / [default seng] Informaon
0x2B0A:001
(P318.01)
Oscillaon damping: Gain
(Oscilla
t. damp.: Gain)
-400 ... [150] ... 400 %
Gain of the oscillaon signal.
•
With the seng 0, oscillaon damping is deacvated.
0x2B0A:002
(P318.02)
Oscillaon damping: Filter me
(Oscillat. damp.: Filter me)
1 ... [30] ... 600 ms
Time constant of the PT1 lter.
Conguring the motor control
V
/f characterisc control for asynchronous motor (VFC open loop)
Set oscillaon damping
150