BONFIGLIOLI ACTIVE Cube ACU 201-01, Руководство по эксплуатации, Страница: 239 / 292

17.5.7 Modulation Controller
The modulation controller, which is designed as an I regulator, automatically adapts
the output value of the frequency inverter to the machine behavior in the basic speed
area and in the field weakening area. If the modulation exceeds the figure set with
parameter
Reference modulation
750, the field-forming current component and thus
the flux in the machine are reduced.
In order to make the best possible use of the voltage available, the figure selected
via parameter
Operation mode
753 is put into proportion to the DC link voltage. That
means that with a high mains voltage there is also a high output voltage available,
the drive only reaches the field weakening area later and produces a higher torque.
Operation mode
753 Function
0 - Usq-Control
The modulation is calculated from the ratio of torque-
forming voltage component U
sq
to the DC link voltage.
1 - V-Absolute Value
Control
The modulation is calculated from the abs. voltage value
/ DC link voltage ratio.
The integrating part of the modulation controller is to be set via parameter
Integral
time
752.
Parameter Settings
No. Description Min. Max. Fact. sett.
750 Reference modulator 3.00 % 105.00 % 102.00 %
752 Integral time 0.0 ms 1000.0 ms 10.0 ms
The percentage setting of the
Reference modulation
750 is basically a function of the
leakage inductivity of the machine. The default value was selected such that in most
cases the remaining deviation of 5% is sufficient as a reserve range for the current
controller. For the optimization of the controller parameters, the drive is accelerated
with a flat ramp into the area of field weakening, so that the modulation controller
intervenes. The limit is set via parameter
Reference modulation
750. Then, the con-
trol loop can be excited with a unit step function by modifying the reference modula-
tion (change-over between 95% and 50%). By means of an oscillographed meas-
urement of the flux-forming current component on the analog output of the frequen-
cy inverter, the controlling process of the modulation controller can be assessed. The
course of the signal of the flux-forming current I
sd
should reach the stationary value
after overshooting without oscillation. An oscillating of the course of the current can
be damped by increasing the integral time. The parameter
Integral time
752 should
roughly correspond to the actual value
Act. rotor time constant
227.
17.5.7.1 Limitation of Modulation Controller
The output signal of the modulation controller is the internal reference flux. The con-
troller output and the integrating part are limited via the parameter
Reference Imr
lower limit
755 or the product of
Rated magnetizing current
716 and
Reference flux
717. The magnetizing current parameter forming the upper limit is to be set to the
rated figure of the machine. For the lower limit, select a value which also builds up
an adequate flux in the machine in the field weakening area. The limitation of the
control deviation at the output of the modulation controller prevents a possible oscil-
lation of the control loop in the case of load surges. The parameter
Control deviation
limitation
756 is stated as an absolute value and acts both as a positive and a nega-
tive limit.
Parameter Settings
No. Description Min. Max. Fact. sett.
755 Reference Imr lower limit 0.01
⋅
I
FUN
ü
⋅
I
FUN
0.01
⋅
I
FUN
756 Control deviation limitation 0.00 % 100.00 % 10.00 %
06/13 Operating Instructions ACU 239