Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 22)

1-4 Overview of Drive
7000L-UM300I-EN-P – June 2013 7000 “C” Frame
Topology
The PowerFlex 7000L “C” Frame drive 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
twelve inverter switching devices are required at 4160V and 18
inverter switching devices at 6600V.
The PowerFlex 7000L “C” Frame drive 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. Silicon-controlled rectifiers
(SCRs) (18 pulse) or SGCTs (for AFE rectifiers) are used for the line
converter switches.
2U (X1)
2V (X2)
2W (X3)
SGCT’s
LINE CONVERTER DC LINK
L+ M+
SGCT’s
MACHINE CONVERTER
U (T1)
V (T2)
W (T3)
L- M-
1U
1V
1W
LR
Figure 1.1 – PWM with Line Reactor (4160 Volt)