7.7.1 Variant 1 (Table)
l
Deactivate table:
P 340[0] - CON_FM_Imag
= 0
l
Select
P 435[0] - CON_FM_FWMode
=
TABLE(1)
l
Run-up slowly to required speeds
l
Set scope: Isdref / sqrt(2)*Imag = % = field-weakening speed. The maximum
amount of the field-weakening d-current is defined by parameter
P 340[0] -
CON_FM_Imag
(specification of effective value).
l
Enter the values in the table;
P 342[0] - CON_FM_SpeedTab
Example
The speeds in P 342[0] - CON_FM_SpeedTab must continuously increase
from index 0 -7.
Index
P 348
Rated
speed;
P 340
I
mag
rms
P 342 (0-7) Field-
weakening speed
[%]
P 343 (0-7)Magnetizing current
in field-weakening mode in [%]
(0)
I
rated
=
1800 rpm
I
mag rms
=
100%
100
0
(1)
110
55
(2)
120
70
(3)
130
90
(4)
140
100
(5)
150
100
(6)
160
100
(7)
170
100
Table 7.27: Example of speeds in
P 342 - CON_FM_SpeedTab
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
148
7 Control
7.7.2 Variant 2 (Calc)
In the case of very rapid speed or load changes in the field-weakening range, the
setting P 435[0] - CON_FM_FwMode =
CALC(2)
must be selected. A characteristic
for higher control dynamism is calculated internally.
Features
l
Very fast adaptations, with high dynamism, are possible (open-loop control
method).
l
Motor parameters must be known quite precisely.
l
If continuous oscillation occurs (voltage limit) the preset negative d-current
value is then not sufficient. Scaling parameter
P 436[0] - CON_FW_SpeedScale
> 100% is used to evaluate the map at
higher speeds.
The voltage controller overlaid over the map (setting as described in variant 1).
The set combination of voltage controller and map entails more commissioning
commitment, but it enables the best stationary behaviour (highest torque relative to
current) and the best dynamic response to be achieved.
ID
Index Name / Setting
Unit Function
435
0
CON_FM_FWMode
Selection mode for field-weakening of
synchronous motors
NONE (0) = Field
weakening disabled
Field-weakening is off, regardless of other
settings.
TABLE (1) = Isd set by PI
controller and table
parameter
Field-weakening is effected by a characteristic
which specifies the d-current (
P 343[0] - CON_
FM_ImagTab
) dependent on the speed (
P 342
[0] - CON_FM_SpeedTab
).
CALC (2) = Isd set by PI
controller and table
parameter
Field-weakening is effected by way of a
characteristic which is set internally via the
Table 7.28: Parameters for selecting field weakening
