Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive (A Frame) - ForGe Control (PanelView 550) - Manual (Page 15)

Overview of Drive 1-3
7000 “A” Frame 7000A-UM151D-EN-P – March 2013
Topology
The PowerFlex 7000 utilizes a Pulse Width Modulated (PWM) –
Current Source Inverter (CSI) for the machine side converter as shown
in Figure 1.1. This topology offers a simple, reliable, cost-effective
power structure that is easy to apply to a wide voltage and power
range. The power semiconductor switches used are easy-to-series for
any medium voltage level. Semi-conductor fuses are not required for
the power structure due to the current limiting DC link inductor.
With 6500 volt PIV rated power semiconductor devices, the number
of inverter components is kept to a minimum. For example, only six
inverter switching devices are required at 2400V, 12 at 3300-4160V,
and 18 at 6600V.
The PowerFlex 7000 has the additional benefit of inherent
regenerative braking for applications where the load is overhauling
the motor, or where high inertia loads need to be slowed down
quickly. Symmetrical Gate Commutated Thyristors (SGCTs) are
used for machine converter switches and line converter switches.
2U (X1)
2V (X2)
2W (X3)
SGCTs
LINE CONVERTER DC LINK
L+ M+
SGCTs
MACHINE CONVERTER
U (T1)
V (T2)
W (T3)
L- M-
Figure 1.1 – PWM-CSI AC Drive