“A” Group: Standard Functions
Configur
ing Dr
iv
e
P
a
ra
meters
3–14
Torque Control
Algorithms
The inverter generates the motor output
according to the V/f algorithm or the
sensorless vector control algorithm. Param-
eter A044 selects the inverter torque control
algorithm for generating the frequency
output, as shown in the diagram to the right
(A244 and A344 for 2nd and 3rd motors,
respectively). The factory default is 00
(constant torque V/f control).
Review the following descriptions to help
you choose the best torque control
algorithm for your application.
• The built-in V/f curves are oriented
toward developing constant torque or
variable torque characteristics (see
graphs below).
• The free-setting curve provides an even
more flexible characteristic, but it
requires more parameter settings.
• Sensorless vector control calculates an
ideal torque vector based on current
motor position, winding currents, and so
on. It is a more robust control method than the V/f control methods. However, it is more
dependent on actual motor parameters and will require you to set these values carefully or to
perform the auto-tuning procedure (see
“Auto-tuning of Motor Constants” on page 4–71
) to
obtain optimum performance.
• Sensorless vector control, 0Hz domain increases the low-speed torque performance (0–
2.5Hz) via an advanced Hitachi torque control algorithm. However, you will need to size the
inverter for one frame size larger than the motor for proper operation.
• Vector control with sensor requires expansion card SJ–FB encoder feedback board and a
motor shaft encoder. Choose this method when precise position/velocity control is required.
A038
Jog frequency setting
0.5 to 9.99 (Hz)
1.00
1.00
1.00
✔ ✔
Defines limited speed for jog
A039
Jog stop mode
FRS
00
Free-run stop, jogging disabled during
motor run
00
00
00
✘ ✔
Defines how end of jog stops
the motor
DEC
0 1
Controlled deceleration, jogging
disabled during motor run
DB
02
DC braking to stop, jogging disabled
during motor run
R-FRS
03
Free-run stop, jogging always enabled
R-DEC
04
Controlled deceleration, jogging always
enabled
R-DB
05
DC braking to stop, jogging always
enabled
Func.
Code
Name/
Description
Keypad
Range and Settings
Defaults
Run
Mode
Edit
Lo Hi
SRW
OPE
FEF2
FE2
(EU)
FUF2
FU2
(USA)
FF2
F2
(Jpn)
Output
V/f control,
constant torque
V/f control,
variable torque
V/f control, free-
setting curve
Inverter Torque Control Algorithms
Sensorless vector
(SLV) control
Sensorless vector,
0Hz domain
Vector control with
sensor
00
05
04
03
02
01
A044