Siemens SINAMICS V20 Operating Instructions Manual page 265

Parameter Function
P1232[0...2] DC braking current
[%]
Defines level of DC current relative to rated motor current (P0305). The DC braking can be issued observing
the following dependencies:
OFF1/OFF3 ==> see P1233
•
BICO ==> see P1230
•
P1233[0...2] Duration of DC brak-
ing [s]
Defines duration for which DC braking is active following an OFF1 or OFF3 command.
When an OFF1 or OFF3 command is received by the converter, the output frequency starts to ramp to 0 Hz.
When the output frequency reaches the value set in P1234, the converter injects a DC braking current
P1232 for the time duration set in P1233.
Caution: See P1230
Notice: The DC braking function causes the motor to stop rapidly by applying a DC braking current.
When the DC braking signal is applied, the converter output pulses are blocked and the DC current not
applied until the motor has been sufficiently demagnetized (demagnetization time is calculated automatically
from motor data).
Note: P1233 = 0 means that DC braking is not activated.
P1234[0...2] DC braking start
frequency [Hz]
Sets start frequency for DC braking.
When an OFF1 or OFF3 command is received by the converter, the output frequency starts to ramp to 0 Hz.
When the output frequency reaches the value set in start frequency of DC braking P1234, the converter
injects a DC braking current P1232 for the time duration set in P1233.
P1236[0...2] Compound braking
current [%]
Defines DC level superimposed on AC waveform after exceeding DC-link voltage threshold of compound
braking. The value is entered in [%] relative to rated motor current (P0305). Compound braking switch-on
level (V_DC,Comp):
If P1254 = 0 --> V_DC,Comp = 1.13 * sqrt(2) * V_mains = 1.13 * sqrt(2) * P0210
otherwise V_DC,Comp = 0.98 * r1242
The Compound Brake is an overlay of the DC brake function with regenerative braking (effective braking at
the ramp) after OFF1 or OFF3. This enables braking with controlled motor frequency and a minimum of
energy returned to the motor. Through optimization of the ramp-down time and the compound braking an
efficient braking without additional HW components is possible.
Dependen- Compound braking depends on the DC link voltage only (see threshold above). This will happen on OFF1,
cy: OFF3 and any regenerative condition. It is disabled, when:
DC braking is active
•
Flying start is active
•
Notice: Increasing the value will generally improve braking performance; however, if you set the value too high, an
overcurrent trip may result.
If used with dynamic braking enabled as well compound braking will take priority.
If used with the Vdc_max controller enabled the converter behavior when braking may be worsened particu-
larly with high values of compound braking.
Note: P1236 = 0 means that compound braking is not activated.
SINAMICS V20 Converter
Operating Instructions, 10/2019, A5E34559884-012
Range Factory
default
0 - 250 100
0.00 - 250.00 0.00
0.00 - 550.00 550.00
0 - 250 0
Can be Scaling Data set
changed
U, T - DDS
U, T - DDS
U, T - DDS
U, T - DDS
Parameter list
8.2 Parameter list
Data Acc.
type Level
U16 2
Float 2
Float 2
U16 2
263