Dc Voltage Control; Overvoltage Control; Undervoltage Control (Power Loss Ride-Through) - ABB ACS280 Firmware Manual

DC voltage control



Overvoltage control

Overvoltage control of the intermediate DC link is typically needed when the
motor is in generating mode. The motor can generate when it decelerates or
when the load overhauls the motor shaft, causing the shaft to turn faster than
the applied speed or frequency. To prevent the DC voltage from exceeding the
overvoltage control limit, the overvoltage controller automatically decreases
the generating torque when the limit is reached. The overvoltage controller also
increases any programmed deceleration times if the limit is reached; to achieve
shorter deceleration times, a brake chopper and resistor may be required.


Undervoltage control (power loss ride-through)

If the incoming supply voltage is cut off, the drive will continue to operate by
utilizing the kinetic energy of the rotating motor. The drive will be fully
operational as long as the motor rotates and generates energy to the drive. The
drive can continue operation after the break if the main contactor (if present)
remained closed.
Note: Units equipped with a main contactor must be equipped with a hold
circuit (e.g. UPS) to keep the contactor control circuit closed during a short
supply break.
T f U
M out DC
(N·m) (Hz) (Vdc)
160 80 520
120 60 390
80 40 260
40 20 130
U
= Intermediate circuit voltage of the drive,
DC
f
= Output frequency of the drive,
out
T
= Motor torque.
M
Loss of supply voltage at nominal load (
the minimum limit. The controller keeps the voltage steady as long as the input power is switched
off. The drive runs the motor in generator mode. The motor speed falls but the drive is operational
as long as the motor has enough kinetic energy.
1.6 5.8
f
= 40 Hz). The intermediate circuit DC voltage drops to
out
Program features 69
8 11.2
U
input power
U
DC
f
out
T
M
t (s)
15.4