BONFIGLIOLI Agile Operating Instructions Manual page 230

The settings of the current controllers should not be too dynamic in order to ensure a sufficient re-
serve range. The control tends to increased oscillations if the reverse range is reduced.
The dimensioning of the current controller parameters by calculation of the time constant is to be
done for a switching frequency of 2 kHz. For other switching frequencies, the values are adapted in-
ternally so that the setting can remain un-changed for all switching frequencies. The dynamic proper-
ties of the current controller improve if the switching and scanning frequency increases.
The fixed time interval for the modulation results in the following scanning frequencies of the current
controller via parameter
Switching frequency
2 kHz
4 kHz
8 kHz
16 kHz
746 Cross-Coupling Factor
For an asynchronous motor (
610), the coupling between the flux-forming current Isd and the torque-forming current Isq can be
undone largely by the activated cross-coupling compensation. In this way, it is possible to impress the
torque-forming current in the machine more quickly and the speed control circuit has a lower tenden-
cy toward vibration.
The cross-coupling exists between the flux-forming current Isd and the torque-forming current Isq
and is caused by the voltage drop at the stator inductivity and the stator leakage inductivity. For this
reason, the cross-coupling increases with the stator frequency. The cross-coupling becomes particular-
ly apparent in the case of high stator frequencies at relatively small switching frequencies (e.g. 300 Hz
stator frequency at 4 kHz switching frequency), as with small switching frequencies, the current con-
troller slows down.
Parameters
No. Description
746 Cross-Coupling Factor
1)
30 = 410
Configuration
2)
30 = 610
Configuration
Cross-coupling compensation can be optimized as follows:
• First, set the speed controller. To that end, define reference speed jumps at small rotary frequen-
Set a speed of approx. 2 3 � of the rated speed.
cies. See chapter 7.9.5.3 "Speed controller".
•
Define reference speed jumps again. During the accelerations, currents Isq of approx. 50% of the
•
rated current should occur.
• Starting from 0%, increase the value of
ple.
• The influence by Isq on Isd during the reference speed jumps should decrease with increasing
values of
Cross-Coupling Factor
cilographed using the scope function of the PC user software. A minimum influence should be
reached at 100%.
Set the
•
Cross-Coupling Factor
Very high values for
Cross-Coupling Factor
break.
Agile
Operating Instructions
400.
Switching Frequency
Setting
Scanning frequency
2 kHz
4 kHz
8 kHz
8 kHz
30 = 410) and synchronous motor (
Configuration
Min.
0.00%
Cross-Coupling Factor
746. For checking, signal sources Isd and Isq can be os-
746 to a value slightly below the determined optimum value.
746 (e.g. 125%) may result in an overcurrent circuit
06/2013
Setting
Max.
300.00%
746 in steps of 25%, for exam-
230
Parameter descriptions
30 =
Configuration
Fact. sett.
1)
100.00%
2)
75.00%
Control functions