Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 214)

4-60 Commissioning
7000A-RM001A-EN-P – January 2011 7000 “A” Frame
• T DC Link
The tuning of the current regulator is controlled by three parameters
– two in the Current Control group, and one in the Drive Hardware
group:
1. Current regulator bandwidth CurReg Bandwidth
2. DC Link time constant T DC Link
3. DC Link inductance in per unit DCLnk Induct pu
Of these three parameters, inductance DCLnk Induct pu is calculated
from its nameplate rating, the current regulator bandwidth should be
set to its default value of 200 rad/sec, and only T DC link is unknown
and must be measured. Although the current regulator was tuned
during factory test, it should be retuned during commissioning
because the dc link time constant is affected by the impedance of the
drive input transformer.
The following auto-tune procedure is used to complete the rectifier
side tuning:
Rectifier
Auto-tuning
1.
Ensure that the parameters in the Drive Hardware and Motor
Ratings groups have been set to the correct values.
2.
Set parameter Autotune Select in the Autotuning parameter group
to Rectifier. The drive will go into DC Current test mode. The
current regulator bandwidth is set to Autotune Idc BW (212).
3.
Start the drive. The dc current will increase to 0.2pu and stay at
that level for couple of seconds. The drive records the data under
this condition and then ramps up to approximately rated current.
After staying at the level for couple of seconds, the drive will again
record the measured data and then ramp the current to zero. The
current regulator bandwidth is set back to the original value. From
the recorded data, the drive will calculate the Autotune L Input
(P217) and Autotune T DCLnk (218). At the end of the tuning Input
Impedance is set to Autotune L Input and T DC Link is set to
Autotune T DCLnk. During tuning if the values are determined to
be out of range, the drive will issue warnings indicated below. Try
to tune the drive again, but if the warnings persist, verify the result
by tuning the drive manually.
Warnings during Rectifier tuning and their interpretation:
L Input Low - indicates that the measured L Input is less than
0.02 pu. The L Input must be tuned using the manual method
described below.
Tuning Procedure (cont.)