Siemens SINAMICS S120 - Page 217

Vector control
5.2 Vector control without encoder (SLVC)
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
217
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 performance:
● Saturation characteristic: p0362 to p0369
● Load characteristic: p0398, p0399
Commissioning sequence for closed-loop controlled operation to zero speed:
● Perform the commissioning with motor data identification at standstill.
● Enter the parameters for the saturation characteristic and the load characteristic.
● Activate closed-loop controlled operation down to zero speed via parameter p1750.5 = 1.
The following advantages are obtained by maintaining closed-loop controlled operation:
● No torque irregularities as a result of changeover operations in the closed-loop control
structure
● Closed-loop speed and torque control without encoder (sensorless) up to and including 0
Hz.
● Higher dynamic performance when compared to open-loop controlled operation
● Encoderless operation of drive line-ups (e.g. in the paper industry, master-slave
operation) is possible.
● Active (including hanging/suspended) loads down to zero frequency.
Note
Motor reactor, sine-wave filter, dv/dt filter
The process cannot be used with the present motor reactors, sine
-wave filters and dv/dt
filters.