Siemens SINAMICS S120 Function Manual page 138

Operating Modes
Vector control
Speed Setpoint
Actual speed
M_
set
p [C]
1503
(0)
p 1 =M_
1501 ctrl active
[ .7] r .
FP 2520 1406 12
M_ 1
suppl
p [C]
1511
(0)
M _ 1
suppl scal
p [C]
1512
(0)
M_ 2
suppl
p [C]
1513
(0)
Fig. 3-35 Closed-loop speed/torque control
The total of the two torque setpoints is limited in the same way as the speed con-
trol torque setpoint. At speeds in excess of the maximum speed (p1182), a speed
limiter reduces the torque limits to prevent the drive from being accelerated further.
True torque control (with self-adjusting speed) is only possible in closed-loop but
not open-loop control for sensorless vector control (SLVC). In open-loop control,
the torque setpoint adjusts the setpoint speed via a ramp-function generator (inte-
gration time ~ p1499 x p0341 x p0342). For this reason, sensorless torque control
at standstill is only suitable for applications that require an accelerating torque but
no load torque (e.g. traction drives). This restriction does not apply to torque con-
trol with sensor.
3-138
K
T
p n
PI speed
controller
0
–
T
i
1
p =M
1300
Ctrl
ψ
M_ 2 scal
suppl
-10 000 %... 10 000 %
p 1514 [D ] (100 .0%)
r
1538
p [0]
1547
r
p [1]
1539
1547
r .2
1407
r
1515
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
r
0079
Torque
setpoint