Pole Position Identification; Operation Without An Encoder - Siemens SINAMICS S120 Function Manual

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Pole position identification

For synchronous motors and synchronous reluctance motors, the pole position identification

(PolID) determines the electrical pole position that is required for the field-oriented control.

When operated with one encoder, which is not adjusted to the pole position, then the

identification is used to calibrate and align the encoder.

Function description

In encoderless operation, select the pole position identification using parameter p1780.6. You

must identify the pole position each time that you switch on the motor to operate it without an

encoder. You set the technique that is suitable for the motor using parameter p1980 - and the

current using p0325 and p0329.

Pole position identification is only possible at standstill

The shaft can move during pole position identification.

The pole position identification is used during the motor data identification to determine the

motor data. Faults F07968 or F07969 can occur during the motor data identification.

Important notes

A suitable technique for the motor is selected using parameter p1980. The following techniques

are available:

● Voltage pulsing 1st harmonic (p1980 = 1)

● Voltage pulsing 2-stage (p1980 = 4)

● Voltage pulsing 2-stage inverse (p1980 = 6)

● Voltage pulsing 2nd harmonic inverse (p1980 = 8)

● Impressing DC current

All of these techniques are only possible at standstill. The fast pole position identification can

be selected if a faster switch-on is required (p1780.13 = 1).

Supplementary conditions

The following supplementary conditions apply for the pulsed techniques (p1980 = 1, 4, 6, 8):

● This procedure can be used for both braked and non-braked motors.

● The specified current magnitudes (p0325, p0329) must be sufficient to provide a significant

measuring result (p0325 is only used for p1980 = 4).

Drive functions

Function Manual, 06/2019, 6SL3097-5AB00-0BP2

Vector control

6.14 Pole position identification