Lenze i510 - Brake Energy Management

10.4 Brake energy management
When braking electrical motors, the kinec energy of the drive train is fed back regeneravely
to the DC bus. This energy c
auses a DC-bus voltage boost. If the energy fed back is too high,
the inverter reports an error.
Several dierent strategies can serve to avoid DC-bus overvoltage:
•
Use of a brake resistor
•
Stopping the deceleraon ramp funcon generator when the brake chopper threshold is
exceeded
•
Use of the "Inverter motor brake" funcon
•
Combinaon of the above named opons
•
DC-bus connecon
Details
The voltage threshold for braking operaon results on the basis of the rated mains voltage set:
Rated mains voltage Voltage threshold for braking operaon
230 V DC 380 V
400 V DC 725 V
480 V DC 775 V
The voltage threshold for braking operaon can be reduced by 0 ... 100 V. The reducon
required can be set in 0x2541:003 (PAR 706/003).
If the DC-bus voltage e
xceeds the voltage threshold for braking operaon, the braking method
selected in 0x2541:001 (PAR 706/001) is applied.
•
Opmum following of the actual frequency value to the frequency setpoint (e.g. quick stop
of the motor) can always be achieved by the use of a brake resistor.
•
Stopping the ramp funcon generator enables smoother deceleraon with lower torque
oscillaon..
•
The "Inverter motor br
ake" funcon allows for quick braking without using a brake resistor.
For process-relat
ed reasons, torque oscillaons may occur.
Parameter Name / value range / [default seng] Info
0x2541:001
(PAR 706/001)
Brake energy manag
ement: Operang mode
(Brake management: Operang mode)
Selecon of the braking method.
•
The braking method(s) selected is/are acvated if the DC-bus voltage
exceeds the voltage threshold for the braking operaon shown in
0x2541:002 (PAR 706/002).
0 Brake resistor The integrated brake chopper (brake transistor) is used.
1 Deceleraon ramp funcon generator stop The deceleraon ramp funcon generator is stopped.
4Stopping the deceleraon ramp funcon generator ^ 156
2
Brake resistor and deceleraon ramp
funcon generator stop
The brake resistor is supplied with current and the deceleraon ramp
funcon generator is stopped.
3 Inverter motor brake and deceleraon ramp
funcon generator stop
Braking with the "Inverter motor brake" braking method in connecon
with "Deceleraon ramp funcon generator stop" is executed.
4Inverter motor brake ^ 157
4 Brake resistor, inverter motor brake, and
deceleraon ramp funcon generator stop
Braking is performed by combining all three braking procedures.
0x2541:002
(P
AR 706/002)
Br
ak
e ener
gy manag
ement: Acve threshold
(Brake management: Acve threshold)
•
Read only: x V
Display of the acve voltage threshold for braking operaon ("brake
chopper threshold").
•
The voltage threshold shown depends on the mains voltage selected
in 0x2540:001 (PAR 208/001) and the voltage value set in 0x2541:003
(PAR 706/003).
•
The voltage threshold must not exceed the steady-state DC voltage
establishing itself in the DC bus!
0x2541:003
(PAR 706/003)
Brake energy manag
ement: Reduced threshold
(Brake management: Red. threshold)
0 ... [0] ... 100 V
The voltage threshold for braking operaon ("brake chopper threshold")
is reduced by the voltage value set here.
Addional funcons
Brake energy manag
ement
155
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