Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 232)

Commissioning 4-73
7000 “B” Frame 7000-UM150I-EN-P – June 2013
3. Start the drive. The step response of the current regulator is
measured and the dc link time constant is adjusted to produce a
critically damped response. This test may take up to two minutes
to perform. When the desired response has been achieved, the
drive shuts off.
The current regulator bandwidth is set back to its normal value and
parameter "Autotune select" is set to Off. Parameter "Autotune Tdc"
indicates the results of the test. If the test is successful, parameter "T dc
link" in "Current Control" is set equal to "Autotune Tdc". If the test
fails, then parameter "T dc link" is not changed and a warning is issued
indicating the cause of the failure:
T dc low - indicates that the measured dc link time constant is
less than 0.020 second. The step response of the current regulator
should be checked using the manual method described below.
T dc high - indicates that the measured dc link time constant is
greater than 0.100 second. The step response of the current regulator
should be checked using the manual method described below.
Current Regulator Manual Tuning
An appropriate value for the “T dc link” parameter can be determined
from the current regulator step response while operating in dc current
test mode. The following procedure should be followed:
1. Be sure that all the parameters in the "Drive Hardware" and
"Motor Ratings" groups have been set to the correct values.
Otherwise, the calculated value of parameter "L DC link" in
"Current Control" will not be correct.
2. Set parameter "Operating mode" in the " Feature Select " to DC
Current to enter dc current test mode.
Current Control Parameter Screen