Index
P 348
rated
speed;
P 340
I
mag
rms
P 342 (0-7) Field
weakening speed
[%]
P 343 (0-7) Magnetizing cur-
rent 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 7.2
5
: Example of speeds in
P 342 - CON_FM_SpeedTab
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
motor parameters. The d-current reference is
then calculated dependent on the speed AND
the required q-current: isd = f(n, isq_ref).
The inaccuracies with regard to the motor
Table 7.2
6
: Parameters for selecting field weakening
MOOG
ID
No.:
CB40859-001
Date:
02/2018
MSD Servo Drive - Device Help
143
7 Control
ID
Index Name / Setting
Unit Function
parameters, the available voltage etc. can be
compensated for with
P 436[0] - CON_FW_
SpeedScale
.
REL (3)
Isd for reluctance model for synchronous motor
Table 7.2
6
: Parameters for selecting field weakening (continue)
CAUTION!
Your system/motor may be damaged if put into operation in
an uncontrolled or inappropriate manner.
Failure to exercise caution or follow proper working
procedures may result in damage to your system/motor.
When configuring projects, it must be ensured that the
speed
NEVER
exceeds the value of the product of
P 458[0] - MOT_SNom
*
P 0328_CON_SCON_SMax
It should be ensured as a matter of principle that the
induced voltage does not exceed the voltage limits.
The maximum system speed must not be exceeded.
7.7.3 Synchronous motor voltage controller field
weakening
The voltage controller is superimposed onto the selected characteristic curve. When
the voltage controller is used, a part of the available voltage is used as a control
reserve. The more dynamic the running, the more control reserve is required. In this
case it may be that the voltage for rated operation is not sufficient, and also that the
controller starts to oscillate.
If the voltage controller oscillates, the gain must be reduced. If substantial variations
between the q-current reference and actual values occur during run-up to reference
speed in the field weakening range, the servo drive may be at the voltage limit. In
