5motor interface – Lenze 9400 User Manual
Page 156
5
Motor interface
5.4
Servo control (SC)
156
Lenze · Servo-Inverter 9400 HighLine · Reference manual · DMS 10.0 EN · 11/2013 · TD05/06
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5.4.1.6
Setting the field weakening for asynchronous machines
For the following setting instructions it is assumed that the drive has been adjusted in the base
speed range (inverter error characteristic, motor parameters, current controller, speed controller,
current setpoint filter, angle controller, torque feedforward control) and is running satisfactorily to
the rated motor speed.
How to set the field weakening for an asynchronous machine:
1. Set the desired maximum speed (with field weakening) in
2. Carry out the following basic setting for the controller parameters for third-party motors:
• Field controller gain (
) = 1 / (2 *
* 500 μs)
• Field controller reset time (
) = motor rotor time constant (
)
• Field weakening controller gain (
) = 0 [Vs/V]
• Field weakening controller reset time (
= 4 ms / (0.3 … 1.0 * 60) *
* 2π *
[rpm] * s
(with factor 0.3 … 1.0 for motor with rated power of 400 kW … 0.4 kW)
Optimising the static behaviour in the field weakening range:
3. By means of speed ramp (acceleration time several seconds), slowly accelerate to the field
weakening range up to maximum speed (
),and decelerate to speed 0 again and
record the signal characteristic using the
(see example oscillogram
).
• From the entry into the field weakening range, the flow setpoint (output of the field
weakening controller) should decrease with 1/n. Influences of the DC-bus voltage may
be seen in the flow setpoint. The signal characteristic should preferably be "smooth".
• From the entry into the field weakening range, the D-current setpoint (output of the
field controller) should always decrease with 1/n. In the signal characteristic no heavy
vibrations may occur.