Siemens SINAMICS V20 Operating Instructions Manual page 249

Parameter Function
P1234[0...2] DC braking start fre-
quency [Hz]
Sets start frequency for DC braking.
When an OFF1 or OFF3 command is received by the inverter, 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 inverter in-
jects 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.
Dependency: Compound braking depends on the DC link voltage only (see threshold above). This will happen on OFF1,
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 inverter behavior when braking may be worsened particu-
larly with high values of compound braking.
Note: P1236 = 0 means that compound braking is not activated.
P1237 Dynamic braking
Dynamic braking absorbs the braking energy in a chopper resistor.
This parameter defines the rated duty cycle of the braking resistor (chopper resistor).
Dynamic braking is active when the function is enabled and DC-link voltage exceeds the dynamic braking
switch-on level.
Dynamic braking switch-on level (V_DC,Chopper) :
If P1254 = 0 --> V_DC,Chopper = 1.13 * sqrt(2) * V_mains = 1.13 * sqrt(2) * P0210
otherwise V_DC,Chopper = 0.98 * r1242
0
1
2
3
4
5
Note: This parameter is only applicable for inverters of frame size D. For frame sizes A to C, the duty cycle of the
braking resistor can be selected with the dynamic braking module (see Appendix "Dynamic braking module
(Page 353)").
SINAMICS V20 Inverter
Operating Instructions, 11/2016, A5E34559884-006
Range Factory
default
0.00 - 550.00 550.00
0 - 250 0
0 - 5 0
Disabled
5 % duty cycle
10 % duty cycle
20 % duty cycle
50 % duty cycle
100 % duty cycle
Can be Scaling
changed
U, T -
U, T -
U, T -
Parameter list
8.2 Parameter list
Data Data Acc.
set type Level
DDS Float 2
DDS U16 2
- U16 2
249