Limiting The Maximum Dc Link Voltage - Siemens SINAMICS G120 CU240B-2 Operating Instructions Manual

Settings
NOTICE
The factory setting of the I
appropriately trained personnel.
Table 7- 19
Parameter
P0305
P0640
P1340
P1341
P1345
P1346
r0056.13
r1343
r1344
For more information about this function, see function diagram 1690 in the List Manual.
7.7.5

Limiting the maximum DC link voltage

How does the motor generate overvoltage?
An induction motor operates as a generator if it is driven by the connected load. A generator
converts mechanical power into electrical power. The electrical power flows back into the
inverter.
As a consequence, the DC link voltage in the inverter increases. The inverter can only
reduce the DC link voltage again if it has an energy recovery feature or it has a braking
resistor.
Above a critical DC link voltage both the inverter as well as the motor will be damaged.
Before the voltage can reach critical levels, however, the inverter switches the motor off with
the fault message "DC link overvoltage".
Inverter with CU240B-2 and CU240E-2 Control Units
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
controller only needs to be changed in exceptional cases by
max
I controller parameters
max
Description
Rated motor current
Motor current limit
Proportional gain of the I
Integral time of the I controller for speed reduction
max
Proportional gain of the I
Integral time of the I controller for voltage reduction
max
Status: I controller active
max
Speed output of I controller
max
Shows the amount to which the I-max controller reduces the speed.
Voltage output of I controller
max
Shows the amount by which the I-max controller reduces the inverter output voltage.
controller for speed reduction
max
controller for voltage reduction
max
Functions
7.7 Protection functions
179