Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 32)

Overview of Drive 1-15
7000 “B” Frame 7000-UM150I-EN-P – June 2013
Control Overview
Motor
Motor
Model
Line
Protection
Machine
Converter
Line
Converter DC Link
inductor
Motor filter
cap
Machine side
feedback and
gating
Line side feedback
and gating
Flux
a
ng
le
Alpha
machine
Ix
c
om
m
an
d
Iy
c
om
m
an
d
Speed
command
Line filter
cap
AC Line
reactor
Idc Feedback
Line voltage
Source
Tach feedback
Slip freq
Stator freq
Speed
Control
Sync
Transfer
Flux
Control
Current
Control
Alpha
line
Machine
Protection
Line
current
Motor
voltage
Motor
current
Speed feedback
Flux feedback
Faults
Faults
Figure 1.7 – PowerFlex 7000 Function Block Diagram
Direct Vector Control
The method of control in the PowerFlex 7000 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 .1-15 radians per second, while the torque bandwidth range
is 20-100 radians per second.