Lenze i700 - Synchronous motor (SM): Pole position identification

Lenze · i700 servo inverter · reference manual · DMS 3.0 EN · 06/2016 · TD06 100
5 Motor control & motor settings
5.10 Synchronous motor (SM): Pole position identification
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5.10 Synchronous motor (SM): Pole position identification
For the control of a permanent-magnet synchronous motor, the pole position – the angle between
motor phase U and the field axis of the rotor – must be known.
• For Lenze motors with an absolute encoder or resolver, the pole position has already been set
correctly.
• When incremental encoders (TTL or sin/cos encoders without absolute position information)
are used, a pole position identification (PPI) is always required after switching on the mains
(initialisation), even with Lenze motors.
Selection criteria for using the suitable pole position identification
For identifying the pole position for the currently activated motor encoder, the three functions are
available that provide nearly the same result. Due to e.g. friction, bearing reactions and a
trapezoidal field characteristic, the results may differ.
Pole position identification PPI (360°)
• The motor must not be braked, blocked or driven mechanically during the pole position
identification! For this reason, this function is not permitted for hanging loads!
• Especially in case of drives in idle state or with a low load (inertia / friction), this function
provides the most exact results of all three PLIs.
Pole position identification PPI (min. movement)
• The motor must not be braked, blocked or driven during the pole position identification! For
this reason, this function is not permitted for hanging loads!
• This function is in the medium range regarding the accuracy. When the current amplitude is
increased in percent, the accuracy of the result may be increased.
Pole position identification PPI (without movement)
• In case of firmly braked motors (e.g. for hanging loads), only this function may be used!
• This function has been developed for a great bandwidth of motor characteristics. In case of
some motor types, the identified pole position angle can considerably differ from the real one
which may result in a significant torque loss and higher motor losses. Hence, especially for
third-party motors, we recommend the execution of a reference identification using the Pole
position identification PPI (360°) with an idling motor.
If the identified values of both processes differ from each other by more than 20°, please
contact Lenze.
• When the current amplitude is increased in percent, the accuracy of the result may be
increased.
You can find detailed information on the respective function in the following subchapters.
 Note!
An identification of pole position (PLI) is only required:
• For servo control with synchronous motor of a third-party manufacturer.
• For servo control with synchronous motor and use of incremental encoders (TTL or
sin/cos encoders as well as resolvers).
• After changes of the motor feedback system, e.g. encoder exchange.