5motor control (mctrl), Stop – Lenze 8400 StateLine User Manual
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Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
201
5
Motor control (MCTRL)
5.8
Sensorless control for synchronous motors (SLPSM)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
, the actually used maximally effective field-producing motor current is displayed.
• With switched-on and active field weakening: 0.00 A ... -x.xx A
• With sensorless control for synchronous motors (SLPSM), the injected current is displayed in
open-loop controlled operation: 0.00 A ... +x.xx A
• If neither field weakening nor open-loop controlled operation are active,e "0.00 A" is
displayed.
Example: Voltage increase in the DC bus when field weakening is switched off
(For instance by an active setting of the controller inhibit or by tripping a fault or error at high motor
speed.)
[5-20] Example: Possible DC-bus voltage > 800 V if field weakening gets lost
Note!
If a Lenze motor is used:
The controller is automatically parameterised so that field weakening operates
optimally and the maximally permissible speed is monitored.
Stop!
If an OEM motor is used:
If pulse inhibit is set in the controller, the DC bus is loaded with the voltage that
corresponds to the current speed of the machine.
Since with switched-on field weakening higher speeds can be achieved at a
correspondingly higher rotor voltage of the motor, the DC bus can be loaded to a voltage
higher than the set DC-bus voltage in case of pulse inhibit and a currently high motor
speed and even exceed the maximally permissible voltage of 800 V!
For device protection, either use a brake chopper or parameterise the motor speed
monitoring via
in such a way that only a maximum speed is possible which
would be also reachable without field weakening with a DC-bus voltage of = 800 V.
Field weakening
Speed n
Motor voltage peak value
Switched off
4000 rpm
560 V
5700 rpm
800 V
6000 rpm
840 V
Switched-on
6000 rpm
560 V
• If pulse inhibit occurs at 6000 rpm and switched-on field
weakening, the DC bus is loaded to more than 800 V ().
• A speed limitation to 5700 rpm is required since this speed
causes a DC-bus voltage of 800 V if field weakening is
switched off.
n
U
4000
840 V
560 V
6000
> 800 V