Rockwell Automation 7000A PowerFlex Medium Voltage Drive (A-Frame) - Classic Control - Manual (Page 245)

Commissioning 4-71
7000 “A” Frame 7000A-UM150F-EN-P – June 2013
6. Measure the average width in degrees of the commutation notch
nearest the peak of the VAB1-OUT waveform as seen in the
following figures.
7. Record the values of the parameters "V line average", and "Idc
reference” in “Current control”
8. Calculate the commutation inductance using the following
formula:
L commutation = V line x sin (notch width) / Idc reference
9. Set parameter "L commutation" to the calculated value. If there
was visible distortion in the reconstructed voltage FAB1, the
distortion should decrease. If the distortion increases, it is
possible that the polarity of the line current feedback is
backwards.
COMMUTATION INDUCTANCE TUNED CORRECTLY COMMUTATION INDUCTANCE INCORRECTLY TUNED
10. Set parameter "Idc command test" to 0.800 pu. The dc current
will increase and the commutation notches will become much
larger.
11. Repeat steps 6 to 9. The higher current will produce a more
accurate measurement of the commutation inductance.