Siemens SINAMICS G120P, Operating Instructions Manual

Page: 370 / 496

Functions
7.6 Protection functions
Inverter cabinet units
370
Operating Instructions, 12/2014, A5E32923362A
Parameters of the Vdc_max control
There are two different groups of parameters for the Vdc_max control, depending on whether
the motor is being operated with V/f control or vector control.
Parameters for
vector control
Parameters for
V/f control
Description
p1240 = 1 p1280 = 1 Vdc_max control Vdc monitoring configuration (factory setting:
1)
1: V
DC max
control enabled
r1242 r1282 V
DC max
control switch-on level
Shows the value of the DC-link voltage above which the V
DC max
control is active
p1243 p1283 V
DC max
control dynamic factor (factory setting: 100 %)
Scaling closed-loop control parameters p1290, p1291 and
p1292
--- p1284 V
DC max
controller time threshold
Sets the monitoring time of the V
DC max
controller
p1250 p1290 V
DC max
control proportional gain (factory setting: 1)
p1251 p1291 V
DC max
control integral time (factory setting p1251: 0 ms, p1291:
40 ms)
p1252 p1292 V
DC max
control rate time (factory setting p1252: 0 ms, p1292: 10
ms)
p1254 p1294 V
DC max
control automatic sensing ON-signal level(factory setting
p1254: 1, p1294: 0)
Activates or deactivates automatic detection of the switch-on
levels of the V
DC max
control.
0: Automatic detection disabled
1: Automatic detection enabled
p0210 p0210 Unit supply voltage
If p1254 or p1294 = 0, the inverter uses this parameter to calcu-
late the intervention thresholds of the V
DC max
control.
Set this parameter to the actual value of the input voltage.
For more information about this function, see the List Manual (function block diagrams 6320
and 6220).
7.6.6 Minimum DC-link voltage limit
With this function, the kinetic energy of the motor is used for buffering the DC-link voltage in
the event of a momentary power failure, thereby decelerating the drive.
Typical cause: Line voltage failure
Remedy: Specify a regenerative torque for the rotating drive to compensate the existing
losses, thereby stabilizing the voltage in the DC link. This process is known as kinetic
buffering.
Kinetic buffering is only possible as long as energy is generated by the movement of the
drive.