Lenze 8400 - Manual (Page 214)

5 Motor control (MCTRL)
5.8 Sensorless control for synchronous motors (SLPSM)
214
Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
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5.8.5 Pole position identification without motion
When sensorless control is active for synchronous motors (SLPSM), the rotor displacement angle is
identified with every controller enable in the Lenze setting and thus a jerk in the machine after
controller enable can be avoided.
The "Pole position identification without motion" is able to identify the electrical rotor
displacement angle with an accuracy of up to 10°. The identification takes 1 ... 15 ms depending on
the motor. The function is preset in the Lenze setting so that no further settings need to be made in
the majority of cases. In order to get the same behaviour as before, the function can be deactivated
in C02874 .
Short overview of the relevant parameters:
• The stator time constants can be calculated based on the following formula:
Parameter Info Lenze setting
Value Unit
C02874 Pole position identification 1: On
C02872 PLI: Adaptation of time period PLI in operation 0
C02875 PLI: Adaptation of ident angle PLI in operation 0 °
C02870 PLI: Degree of optimisation - %
C02871 PLI: Identification time - ms
C02873 PLI: Identified rotor displacement angle - °
Highlighted in grey = display parameter

Note!
In case of synchronous motors with a stator time constant < 1 ms, the pole position
identification is not executed since the resulting test current pulse could exceed the
permissible motor current.
• This, however, only affects very few synchronous motors with very low power (e.g.
Lenze motor MDSKS-020-13-300 with rated power of 40 W).
• A non-executed pole position identification can be recognised by the display
C02870 = 0 % and C02871 = 0 ms.
T
S
= stator time constant
L
ss
= Motor stator leakage inductance ( C00085 )
R
s
= Motor stator resistance ( C00084 )
T
s
[ms]
L
ss
[mH]
R
s
Ω [ ]
-------------------- =