Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 49)

Rockwell Automation Publication 750-RM002B-EN-P - September 2013 49
Drive Configuration Chapter 1
Figure 6 - PowerFlex 750-Series Bus Regulation – Both Adj First
Flux Vector (FV) Control
With the Regen Power Limit left at default, and a decel time of 0.1 seconds, the
drive is limiting the amount of power to a point where the resistor could be
heating up due to duty cycle considerations. So the drive stops the DB transistor
from firing and switches to “Adjust Frequency” to regulate the bus and then
enables another DB pulse and then back to adjust frequency and so on until the
bus voltage remains below the trigger level.
Figure 7 - PowerFlex 750-Series Bus Regulation – Both DB First FV
If the Regen Power Limit is opened up to 100% for instance, the plot will look
exactly the same as the Sensorless Vector mode plot show below.
800
780
760
740
720
700
680
660
12
10
8
6
4
2
0
-2
-0.2 0 0.2 0.4 0.6 0.8 1 1.2
DC Bus Voltage DC Current
DC Bus
Seconds
DC B
us
V
olt
s
10
Vol
ts = Base
Speed
Speed Fdbk
Motor Speed
Brake Current
900
800
700
600
500
400
300
200
100
0
14
12
10
8
6
4
2
0
-2
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
DC Bus Voltage DC Current
DC Bus
Seconds
DC B
us
V
olt
s
10
V
olt
s =
B
ase
Sp
ee
d
Speed Fdbk
Motor Speed
Brake
Current