Pole Position Identification - Siemens SINAMICS S120 Function Manual

Operating Modes
Servo control
Example of speed setpoint step change
A rectangular step change can be applied to the speed setpoint via the speed set-
point step change measuring function. The measuring function has preselected the
measurement for the speed setpoint and the torque-generating current.
Fig. 3-20
Parameter overview
See section "Speed controller".
3.1.13

Pole position identification

Description
For synchronous motors, the pole position identification determines its electrical
pole position, that is required for the field-oriented control. Generally, the electrical
pole position is provided from a mechanically adjusted encoder with absolute infor-
mation. In this case, pole position identification is not required. For the following
encoder properties, pole position identification is not required:
S Absolute encoder (e.g. EnDat)
S Encoder with C/D track and pole pair number v 8
S Hall sensor
S Resolver with a multiple integer ratio between the motor pole pair number and
the encoder pole pair number
S Incremental encoder with a multiple integer ratio between the motor pole pair
number and the encoder pulse number
The pole position identification is used for:
S Determining the pole position (p1982 = 1)
S Determining the angular commutation offset during commissioning (p1990 = 1)
S Plausibility check for encoders with absolute information (p1982 = 2)
3-108
K is optimum K
p_n p_n
overshoots
––>OK ––>not OK
Setting the proportional gain K
is too high, K is too low,
p_n
damped
transient response
––>OK, not optimum
p
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition