Siemens SINAMICS S120 Function Manual page 216

Vector control
6.2 Vector control without encoder (SLVC)
When the function is activated, at low speeds, additional noise can be heard, depending on the
motor design.
The procedure is suitable for motors with internal magnets.
Figure 6-5 Zero point in closed-loop operation down to zero speed
Note
Only open-loop controlled operation is permitted when using a sine-wave filter.
Note
1FW4 torque motors
Siemens "1FW4" torque motors can be started from standstill and operated in the closed-loop
torque controlled mode. The function is activated with parameter p1750.5 = 1.
Third-party motors must be checked on a case-for-case basis.
Supplementary conditions for the use of third-party motors
● The procedure is very suitable for motors with magnets within the rotor core (IPMSM -
Interior Permanent Magnet Synchronous Motors).
● The ratio of stator quadrature reactance (Lsq): Stator direct-axis reactance (Lsd) must be >
1.5.
● The asymmetrical reactance ratio (Lsq:Lsd) is maintained in the motor up to a certain
current; this determines the possible operating limits of the method. If the procedure should
be operable up to the rated motor torque, then the reactance ratio must be retained up to the
rated motor current.
The following parameter input is prerequisite for optimal response:
● Saturation characteristic: p0362 to p0369
● Load characteristic: p0398, p0399
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Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions