MOOG
ID
No.:
CB40859-001
Date:
02/2018
MSD Servo Drive - Device Help
124
7 Control
ID
Index Name
Unit Description
471
0
MOT_Lsig
mH
472
MOT_LsigDiff
472
0
Lsig_q@I0
%
Motor leakage inductance (ASM) / stator
inductance (PSM)
q-axis stator inductance variation (relative to
MOT_Lsig)
Inductance @ CurrentI0
472
1
Lsig_q@I1
%
472
2
Lsig_q@I2
%
472
3
Lsig_q@I3
%
Inductance @ CurrentI1
Inductance @ CurrentI2
Inductance @ CurrentI3
472
4
CurrentI0
%
472
5
CurrentI1
%
472
6
CurrentI2
%
472
7
CurrentI3
%
Current I0 relative to MOT_CNom
Current I1 relative to MOT_CNom
Current I2 relative to MOT_CNom
Current I3 relative to MOT_CNom
Table 7.5: “Advanced torque control - Saturation characteristic” parameters
7.3.5.1.2 K-T characteristic
In the overload range the output-side torque is reduced due to rising losses
(iron/copper losses). This behaviour can be compensated by P 479[0] - MOT_
TorqueSat.
P No.
Index Parameter name
Unit Function
479
MOT_TorqueSat
0 to 4
Nm
5 to 9
A
Motor torque as a function of the current
Torque; interpolation points 0 to 4.
Current; interpolation points 5 to 9.
Table 7.6: “K-T characteristic” parameters
7.3.5.2 Observer
The speed controller must track a variable moment of inertia in order to adapt the
Servo controller to the machine mechanism (adaptive process). The challenge lies
in precise definition of the moment of inertia, in particular under the influence of
friction, load and other non-modellable disturbances. To nevertheless optimize the
adaptation to the machine mechanism, a technique based on a state observer is
available.
NOTE
Please contact
Moog
before configuring the observer.
ID
Index Name
Unit Description
433
0
434
434
0
ms
434
1
1/s
434
2
CON_CCON_ObsMode
CON_CCON_ObsPara
TF
Kp
Tn
ms
Select current observer mode
Current observer parameters
Observer time constant
Proportional feedback gain
Integral feedback time constant
Table 7.7: “Advanced torque control - Observer” parameters
7.3.5.3 Overmodulation
The "usqref" and "usdref" components permit so-called overmodulation of the DC
link voltage (limitation to hexagon instead of circle). The maximum output voltage
which can be set for each phase angle results from the circle which fits in the voltage
hexagon (see diagram Section "“Circle and hexagon voltages” diagram" on page
125).
By setting the hexagon modulation "HEX_PHASE(3)", the length of the vector for the
output voltage can be placed in the area of the DC link voltage (red). As a result only
two of the three half-bridges are switched in each switching interval. The third
remains at the upper or lower potential of the DC link voltage for a period of 60° of
the output frequency.
This method has only two thirds of the switching losses of modulation with all three
phases. Disadvantages are higher harmonics of the motor currents and thus less
smooth running at high motor speeds.
Representation of the eight vectors of the three-phase voltage system (3 half-bridges
each with 2 states [2
3
]). The vectors correspond to the DC link voltage U
ZK
and form
a voltage hexagon.
