Siemens SINAMICS G220 - Vdc_Max Controller (Voltage Limitation)

p1240[0...n] Vdc controller or Vdc monitoring con󹪝guration 
p1245[0...n] Vdc_min controller switch-in level (kinetic bu󹪜ering) [%]
r1246 Vdc_min controller switch-in level (kinetic bu󹪜ering) [V]
p1247[0...n] Vdc_min controller dynamic factor (kinetic bu󹪜ering) [%]
p1255[0...n] Vdc_min controller time threshold [s]
p1256[0...n] Vdc_min controller response (kinetic bu󹪜ering) 
p1257[0...n] Vdc_min controller speed threshold [rpm]
14.10.5.5 Vdc_max controller (voltage limitation)
Overview
The Vdc_max control limits the DC link voltage in the converter and prevents unwanted
switching o󹪜 of the motor.
Requirement
The Vdc_max control is suitable for applications with short-time generator operation of the
motor, e.g. pumps or fans.
Excluding applications with continuous generator operation of the motor, e.g. hoists or
centrifuges.
Description of function
If the converter cannot transfer the electrical energy delivered by the motor during braking, e.g.
to a braking resistor, the converter stores the energy in its DC link capacitors. This causes the DC
link voltage Vdc in the converter to increase.
An excessively high DC link voltage damages the converter as well as the motor.
The Vdc_max control extends the ramp-down time of the motor when braking.
Consequently, the motor feeds only so much energy back into the converter to cover the
losses in the converter. The DC link voltage remains in the permissible range.
The following 󹪝gure illustrates the motor and converter protection in the case of overvoltage.
Functions
14.10Closed-loop drive control
SINAMICS G220 converter
Operating Instructions, 04/2024, FW V6.2, A5E51781573B AB 513