Lenze 8400 StateLine - Manual (Page 188)

5 Motor control (MCTRL)
5.8 Sensorless control for synchronous motors (SLPSM)
188
Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
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If the mass inertia of the drive is unknown, the optimisation can be achieved as follows:
1. Specify speed setpoint.
• A small speed just above the switching threshold is recommended in the closed-loop
controlled operation.
2. Increase Vp ( C00070/3 ) until the drive starts to oscillate (observe engine noise).
3. Reduce Vp ( C00070/3 ) until the drive runs stable again.
4. Reduce Vp ( C00070/3 ) to approx. half the value.
5. Afterwards check results of the optimisation in the entire speed range (one-time passing
through of the speed range).

Tip!
Values recommended by Lenze for the setting of the (proportional) gain:
• For drive systems without feedback: Vp = 2 … 8
• For drive systems with a good disturbance behaviour: Vp > 6
Speed controller reset time Ti
Apart from setting the P component,
C00071/3 provides the possibility to take influence on the I
component of the PI controller.
If the mass inertia of the drive is unknown, the optimisation can be achieved as follows:
1. Specify speed setpoint.
2. Reduce Ti (
C00071/3 ) until the drive starts to oscillate (observe engine noise).
3. Increase Ti ( C00071/3 ) until the drive runs stable again.
4. Increase Ti ( C00071/3 ) to approx. twice the value.

Tip!
Value range recommended by Lenze for the setting of the reset time:
Ti = 20 ms … 150 ms
Using the ramp response for setting the speed controller
If the mechanical components cannot be operated at the stability limit, the ramp response can also
be used for setting the speed controller.

Stop!
If the controller parameters are preset unfavourably, the control can tend to heavy
overshoots up to instability!
• Following and speed errors can adopt very high values.
• If the mechanics are sensitive, the corresponding monitoring functions are to be
activated.