Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 287)

4-82 Commissioning
7000L-UM300I-EN-P – June 2013 7000 “C” Frame
3. Set parameter "Idc command test" in "Current Control" to 0.400
pu.
4. Set parameter "Curreg Bandwidth" in “Current Control” to 100
rad/sec. A lower than the normal bandwidth makes the step
response easier to measure.
5. Set parameter "T dc link" in “Current Control” to 0.020 sec,
which is at the low end of the normal range of values and should
produce an underdamped response.
6. Assign parameters "Idc Reference" and "Idc Feedback" in the
“Current Control” group to 2 SCBL test points (Rect TP1 and 2).
This can be done similarly to the way that the meter assignments
were described earlier in the chapter. Then they can be
displayed on your oscilloscope.
7. Start the drive. The dc link current will rise to 0.4 pu.
8. Set parameter "Idc ref step" in “Current Control” to 0.200 pu.
The dc link current will step up and down by this amount at
regular intervals.
9. Adjust the scope to trigger on the rising edge of the dc current
reference and observe the dc current feedback on the other
channel. The step response will probably have noticeable
overshoot, indicating that the dc link time constant is set too low.
10. Adjust parameter "T dc link" until the current feedback rises to
about 63% of its final value in 10 ms as shown in the figure. The
overshoot should now be quite small. Increasing “T dc link“
causes the rise time to increase. Since the desired step response
is slightly underdamped, “T dc link” should not be increased
beyond the value at which the overshoot disappears.
CURRENT REGULATOR TUNED CORRECTLY