Front End; Dc Link; Fig. 2-3 Dc Link - ABB ACS5000 User Manual

ABB
2.3.1

Front end

2.3.2

DC link

Charging unit
Charging
Stand-by mode
Discharging
5k A UM
The front end of the drive consists of three 12-pulse diode rectifiers. The
three rectifiers add up to a network-friendly 36-pulse system. The front end
rectifies the AC line voltage of the supply network and connects its output
to the minus, neutral point, and plus of the DC link. The front end allows
two-quadrant operation.
The DC link consists of the charging unit (1), the grounding switches
and the DC capacitors (3).
1
Fig. 2-3 DC link
The unit charges the DC-link capacitors before the MCB is closed to
connect the drive to the main power supply. Thus, excessive inrush
currents are prevented.
The charging unit is fed from the auxiliary power supply and charges the
DC link to 90% of the steady state voltages.
The charging sequence is started by pressing the SUPPLY ON push-
button on the control compartment door. After the charging sequence has
finished, the charging unit is disconnected from the medium voltage
circuit, the MCB is closed and the DC link will reach its nominal level.
Once the DC link is charged, it is possible to keep the drive in this state to
facilitate a more rapid startup procedure. The losses during stand-by
mode are approx. 1% of the nominal power and are caused from small
losses from the rectifiers, the inverters and the auxiliaries.
Discharging is initiated by pressing the SUPPLY OFF pushbutton on the
control compartment door. The energy stored in the DC link is dissipated
in the parasitic resistors of the power part of the drive.
3BHS221906 ZAB E01 Rev. D
Chapter 2 - Power electronics and cabinet features
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