Lenze 8400 - Manual (Page 239)

Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
239
5 Motor control (MCTRL)
5.9 Servo control (SC)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Field weakening controller
The field weakening controller serves to adapt the magnetising current when the maximum control
voltage has been reached so that in steady operation approximately 95 % of the maximally possible
control voltage is output. Thus, there is a voltage reserve for dynamic load or speed variations.
[5-24] Recommendation for setting the gain of the field controller (for Tn ≈ 10 ... 30 ms)

Tip!
If the field weakening controller is parameterised unfavourably, vibrations occur in the
magnetising current, in the direct-axis current and in the cross current, in the torque and in
the speed in the field weakening range. This is also audible by an increased motor noise
(humming). The vibrations can be dampened by a decrease of the proportional gain of the
field weakening controller.
Procedure:
• Operate the drive with max. required speed in the field weakening operation.
• Reduce Vp (
C00577 ) of the field weakening controller until the vibration response
cannot be detected anymore.
Parameter Info Lenze setting
Value Unit
C00577 SC: Vp field weakening controller 0.0010
C00578 SC: Tn field weakening controller 20.0 ms
V
P,FW
: Gain of the field weakening controller ( C00577 )
L
m
: Mutual motor inductance ( C00092 )
L
sl
: Motor stator leakage inductance ( C00085 )
p = number of pole pairs
V
P, FS
2
V
Path, FS
-------------------- ≈
V
Path, FS
1 σ –
σ
------------
p 2 π n
N
⋅ ⋅ ⋅
60
------------------------------ σ L
h
L
ss
+ ( )
2
⋅ ⋅ ⋅ =
σ 1
L
h
( )
2
L
h
L
ss
+ ( )
2
-------------------------- – =