Pole Position Identification - Siemens SINAMICS S120 Function Manual

4.15.2

Pole position identification

Description
The pole position identification routine is used to determine rotor position at start up. This is
required when no pole position information is available. If, for example, incremental encoders
are used or operation without encoder is employed, then pole position identification is started
automatically. For operation with encoder, pole position identification can be started via
p1982 = "1", or via p1780.6 = "1", for operation without encoder .
If possible, pole position identification should be carried out in decoupled state. If there is no
large moment of inertia and there is negligible friction, then the identification can also be
carried out in coupled state.
If there is negligible friction and high moment of inertia, then the dynamic response for the
speed encoder can be adjusted to the moment of inertia by increasing p1999.
If there is high friction torque or an active load, then an adjustment is only possible in
decoupled state.
Three pole position identification techniques can be selected:
● p1980 = 1, voltage pulsing, first harmonic
● p1980 = 4, voltage pulsing, two-stage
● p1980 = 10, DC current impression
Integration
The pole position identification is integrated into the system as follows:
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
4.15 Instructions for commissioning permanent-magnet synchronous motors
This technique also functions for magnetically isotropic motors if adequate iron saturation
can be achieved.
This technique functions with motors that are magnetically anisotropic. During the
measurement, the motor must be at a standstill. The measurement is carried-out the next
time that the pulses are enabled.
Note
Using this type of identification, the motor can emit a significant amount of noise.
This technique functions for all motors; however, it takes more time than the
measurement selected using p1980 = 4. During the measurement, the motor must be
able to rotate. The measurement is carried-out the next time that the pulses are enabled.
For extremely high moments of inertia, the run time can be scaled higher using p1999.
WARNING
The measurement can electrically trigger a rotation or movement of the motor, by up to
a half rotation.
Vector control
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