13.7.1 Correcon of the stator leakage inductance (Lss)...
...and the curr
ent controller parameters by means of the saturaon characterisc
For the most part, the electrical characteriscs of the motor are the relevant factors for an
opmal current controller seng (Vp, Ti), especially the stator resistance and the stator leak-
age inductance (Lss). However, modern motors have their stator leakage inductance changed
along with the current level so that it is impossible to have an opmal current controller set-
ting for all working points at all mes.
For applicaons with operang phases that involve very dierent current and torque require-
ments and, at the same me, high requirements on dynamic drive behaviour, the i700 servo
inverter provides the possibility of the correcon of the stator leakage inductance and the cur-
rent controller sengs by means of the adjustable saturaon characterisc.
The saturaon characterisc is a typical characterisc of motors of one type/size. It does not
depend on the maximum process current of the motor in the prevailing applicaon. Thus the
dened values should be based on the key data of the motors. These are rated motor current,
peak motor current for a limited me and the ulmate motor current.
NOTICE
Impact of the saturaon
characterisc on the current controller feedforward control
▶
The saturaon characterisc is not only used to correct the current controller, but it also
inuences the current controller feedforward control (can be acvated via parameter
0x2941).
The following picture shows a typical saturaon
characterisc of an MCS motor:
0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 %
0 %
20 %
40 %
60 %
80 %
100 %
120 %
I/I
max
L/L
n
The saturaon
characterisc represents the change in inductance (L/Ln) as a funcon of the
motor current (I/Imax). The variables of both axes which were scaled to a reference value are
represented as percentages.
•
When a Lenz
e motor is selected, the
saturaon characterisc is already lled with values
typical of the series.
Conguring the motor control
Fine adjus
tment of the motor model
Correcon of the stator leakage inductance (Lss)...
251