Rockwell Automation 20Y PowerFlex Active Front End - Manual (Page 16)

16 Rockwell Automation Publication 20Y-UM001E-EN-P - July 2014
Preface
Description of Operation The PowerFlex Active Front End is a regenerative DC bus supply that is used to
supply DC power to a lineup of common DC bus drives or a single common bus
drive. The AFE uses a PWM (Pulse Width Modulated)-controlled IGBT
converter to allow bi-directional power flow to the AC line. The following
figures show examples of the AFE powering a lineup of PowerFlex 755 drives and
the AFE powering a single PowerFlex 755 drive. For additional information and
bus conditioning requirements, see Drives in Common Bus Configurations,
publication DRIVES-AT002.
Figure 1 - AFE Supplying a Lineup of Common Bus Drives
Figure 2 - AFE Supplying a Single Drive
Active current and reactive currents are calculated from the three input phase
current measurements (I
L1
, I
L2
, and I
L3
) as shown in Figure 3 . The DC voltage
controller is a PI type regulator. A DC voltage reference sets the value of the DC
link voltage to be maintained. It is compared to measured DC voltage to obtain a
DC voltage error as the input for the DC voltage controller.
L1
L2
L3
3-Phase
400VAC
DC+
DC+
DC-
DC-
BR1 BR2
M
L1 L1
L2 L2
L3 L3
DC+ DC- BR1 BR2
M
PowerFlex 755
See publication DRIVES-AT002
for bus conditioning requirements.
PowerFlex
Active Front End
PowerFlex 755
DC+ DC- BR1 BR2
M
L1 L1
L2 L2
L3 L3
DC+ DC- BR1 BR2
M
PowerFlex 755 PowerFlex 755
Bus Conditioner
*
*
*
L1
L2
L3
3-Phase
400VAC
DC+
DC-
M
DC+
DC-
PowerFlex 755 PowerFlex
Active Front End
See publication DRIVES-AT002
for bus conditioning requirements.
*
*
Bus Conditioner
*