Vdc Control - Siemens SINAMICS S120 Function Manual

5.10

Vdc control

The "Vdc control" function can be activated using the appropriate measures if an overvoltage
or undervoltage is present in the DC link.
● Overvoltage in the DC link
● Undervoltage in the DC link
Note
During operation of the Braking Module, the following must be observed:
• You must set the threshold of the Braking Module below the V
• You must switch off the V
Properties
● V
● V
● V
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
– Typical cause
The drive is operating in regenerative mode and is supplying too much energy to the
DC link.
– Remedy
Reduce the regenerative torque to maintain the DC-link voltage within permissible
limits. With the Vdc controller activated, the converter automatically partly extends the
ramp-down time of a drive if the shutdown supplies too much energy to the DC link.
– Typical cause
Failure of the supply voltage or supply for the DC link.
– Remedy
Specify a regenerative torque for the rotating drive to compensate the existing losses,
thereby stabilizing the voltage in the DC link (kinetic buffering).
control
dc
– This comprises V
dc_max
independent of each other.
– Joint PI controller. The dynamic factor is used to set V
independently of each other.
control
dc_max
– This function can be used to control momentary regenerative load without shutdown
using "overvoltage in the DC link".
– V control is only recommended with a supply without active closed-loop control
dc_max
for the DC link and without feedback.
control (kinetic buffering)
dc_min
– 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 delaying the drive.
controller.
dc_max
control and V control (kinetic buffering), which are
dc_min
Vector control
5.10 Vdc control
threshold.
dc_max
and V control
dc_min dc_max
215