Rockwell Automation 7000A PowerFlex Medium Voltage Drive (A-Frame) - Classic Control - Manual (Page 246)

4-72 Commissioning
7000A-UM150F-EN-P – June 2013 7000 “A” Frame
12. Confirm that the commutation inductance is set to the correct
value by increasing the horizontal and vertical magnification and
observing the zero crossing of reconstructed voltage FAB1.
Because the line converter firing angle is about 90 degrees, the
commutation notch occurs near the zero crossing of the
reconstructed voltage. The signal should be a straight line
through the zero crossing with almost no visible distortion.
Either increasing or decreasing parameter “ L Commutation“
should cause the distortion to increase.
13. Stop the drive. Set parameters “Operating mode” to normal and
"Idc command test" to zero.
2. Current Regulator
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. “Curreg bandwidth”
2. "T dc link"
3. "L dc link”
Of these three parameters, inductance “L dc link“ 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.
Current Regulator Autotuning
The current regulator can be tuned automatically using the following
procedure:
1. Ensure that 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 "Autotune select" in "Autotuning" to Current Reg.
The drive will go into dc current test mode. The current regulator
bandwidth is temporarily set to the value specified by parameter
"Autotune Idc BW”. The dc current command is set to the value
specified by parameter "Autotune Idc cmd". The dc current step is
set to the value specified by parameter "Autotune Idc stp".