Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 33)

Overview of Drive 1-15
7000 “C” Frame 7000L-UM300I-EN-P – June 2013
Control Overview
Motor
Stator Freq.
Line
Converter
Feedback
Line
Conversion
Protection
(HW)
Line gating
and diagnostic
feedback
Slip Freq.
Speed Feedback
Torque current command
Flux
Torque
Machine Converter Line Converter
Line
side
control
DC Link
Inductor
Motor filter cap.
Faults
Fa
ult
s
Line
Converter
Protection
Faults
Line
Synch
Current
Control
Machine
side
control
Idc ref
Line
c
on
ver
ter
fi
ring
an
gle
M
ac
hine
c
on
ver
ter
fir
ing
an
gle
Sy
nc
. an
gle
Flux
Control
Mag. Current
command
Machine gating
and diagnostic
feedback
Machine
Converter
Feedback
Machine
Converter
Protection
(HW)
Machine
Converter
Protection
(SW)
Motor
Model
Speed
Control
Speed
Command
Ta
ch
. Fe
ed
ba
ck
Speed Ref. Skip Speed
and
Speed Ramp
Synch.
Transfer
Ref. Current
and Phase Shift
Calculator
Figure 1.10 – PowerFlex 7000L Function Block Diagram
Direct Vector Control
The method of control in the PowerFlex 7000L “C” Frame medium
voltage AC drive is called sensorless direct vector control, meaning
that the stator current is divided into torque producing and flux
producing components, allowing the motor torque to be changed
quickly without affecting motor flux. This method of control is used
without tachometer feedback for applications requiring continuous
operation above 6 Hertz and less than 100% starting torque.
Full vector control can also be achieved with tachometer feedback
for applications requiring continuous operation down to 0.2 Hertz
with up to 150% starting torque. Vector control offers superior
performance over volts/hertz type drives. The speed bandwidth
range is 5-25 radians per second, while the torque bandwidth range is
15-50 radians per second.