Moog MSD Servo Drive Series

7.7Field weakening and LookUpTable (LUT),
At their rated voltage, synchronous motors can also be operated above their rated
speed by injecting a current component in order to reduce their voltage
consumption.
Features
 Themethodisrelativelyrobustagainstparameterfluctuations.
 Thevoltagecontrollercanonlyfollowrapidspeedandtorquechangestoa
limiteddegree.
 Anon-optimizedvoltagecontrollermaycauseoscillation;thecontrollermust
beoptimized.
Conditions
To effectively reduce the voltage consumption, the ratio of stator inductance P471[0]
- MOT_Lsig multiplied by the rated current P457[0] - MOT_CNom to rotor flux P462
[0] - MOT_FluxNom must be sufficiently large. In contrast to field weakening of
asynchronous motors, synchronous motors can also be operated in the "field
weakening range" with full rated torque at the nominal value of the q-current. Power
beyond the rated power output can therefore be drawn from the machine in field
weakening mode, even at rated current. This must be taken into consideration when
configuring the motor.
CNom*Lsig> Factor *FluxNom
A value greater than 0.2 is recommended for Factor .
MOOG
ID
No.: CB40859-001 Date: 02/2018
MSD Servo Drive- Device Help
141
7 Control
Voltage demand
Rotorflux * Maximumspeed(inrad/s) *
Numberofpole
pairs
* <
800V(400V
devices)
400V(230V
devices)
P462[0] *
P458
[0]
*
P328
[0]
* * P463[0] * <
800V(400V
devices)
400V(230V
devices)
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.
 Ifthespeedachievedbyfieldweakeningissohighthat
theinducedvoltageexceedstheovervoltagethreshold
ofthedevice(for400Vdevicesapproximately800V,
for230Vdevicesapproximately400V),thiswillresult
indestructionoftheservodriveifnoadditionalexternal
safetymeasuresareapplied.
There are two variants for field weakening of a synchronous motor. The choice of
variant 1 or 2 is made via P435[0] - CON_FW_FWMode.
From firmware 124.20-08 additional document
CC41778-001 applies
synchronousmotor