Lenze 8400 TopLine - Manual (Page 255)

Lenze · 8400 TopLine · Reference manual · DMS 6.0 EN · 06/2014 · TD05/TD14
255
5 Motor control (MCTRL)
5.9 Servo control (SC)
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
Tip!
Lenze recommend to activate the additional limitation of the speed controller's I
component on reaching the voltage limit ( C00079 = 1) if dynamic acceleration processes in
the field weakening range are wanted.
• The function should be deactivated again if slight speed variations occur in the field
weakening range.
• If this function is activated, the actual speed value may not follow the speed setpoint
correctly in the field weakening range.
5.9.4.9 Feedforward control of the current controller
In C00079/1 , the feedforward control of the current controller can be switched on. The feedforward
control serves to unload the current controller so that the current control loop is able to operate
more stable and dynamically. The feedforward control can contribute to dampen vibrations at very
high speeds.
Before the feedforward control is activated in
C00079/1 , we recommend the execution of the motor
parameter identification in order to get an optimum result with the feedforward control.
 Automatic motor data identification ( 141)

Note!
Function only possible with servo control (SC) for asynchronous motors!

Note!
If the data of the motor equivalent circuit (motor magnetising inductance, motor stator
leakage inductance, motor stator resistance, motor rotor resistance) are not known, the
feedforward control of the current controller must not be switched on as otherwise it
might cause instabilities in the control loop!
Up to and including version 13.xx.xx the following applies:
The feedforward control of the current controller may only be switched on in C00079/1
if the motor magnetising inductance set in C00092 is not more than 4 % higher than the
real magnetising inductance of the connected motor detected by an identification
process. Otherwise, instabilities may occur at high speeds in the control loop and the
motor can accelerate in an uncontrolled manner up to maximum speed.
• The magnetising inductance of a motor has a tolerance of more than 4 % so that this
problem might occur when the motor parameters are loaded from the »Engineer«
motor catalogue and the feedforward control of the current controller is activated.
• If the feedforward control is to be used and instabilities occur: Reduce the motor
magnetising inductance ( C00092 ) until a stable behaviour occurs or carry out a motor
parameter identification.
From version 14.00.00 the following applies:
The feedforward control of the current controller operates properly within the
tolerances of the motor. It is sufficient to select the motor from the »Engineer« motor
catalog or enter the data of the motor equivalent circuit manually.