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Application Notes
C-3
PowerFlex 700S Phase II AC Drive User Manual -
Publication 20D-UM006G-EN-P – July 2008
Field Oriented Control, Permanent Magnet Motor Control, and Volts/Hertz
Control are described in further detail below.
Field Oriented Control
Field oriented control is used with AC squirrel cage induction motors for
high performance. Motor data and an autotune is required for correct
operation in this mode. Field oriented control is selected by setting
parameter 485 [Motor Ctrl Mode] = 0 "FOC".
In field oriented control, the drive takes the speed reference that is specified
by the Speed Reference Selection Block and compares it to the speed
feedback. The speed regulator uses Proportional and Integral gains to adjust
the torque reference for the motor. This torque reference attempts to operate
the motor at the specified speed. The torque reference is then converted to
the torque producing component of the motor current.
This type of speed regulator produces a high bandwidth response to speed
command and load changes. In field oriented control the flux and torque
producing currents are independently controlled. Therefore, you can send a
torque reference directly instead of a speed reference. The independent flux
control also allows you to reduce the flux in order to run above base motor
speed.
Ad
a
ptive
Controller
High B
a
ndwidth C
u
rrent Reg
u
l
a
tor
S
PEED REF.
TORQUE REF.
S
LIP
S
PEED FEEDBACK
CURRENT FEEDBACK
AUTOTUNE PARAMETER
S
V m
a
g
V
a
ng
C
u
rrent
Reg.
S
peed
Reg.
Fl
u
x
Reg.
Volt
a
ge
Control
Inverter
Motor
Encoder