OnLine Power Battery Backup System - Manual (Page 12)

OLP
Three Phase UPS Systems
1. SYSTEM OVERVIEW
1-8
1.3. Rectifier
The main function of a rectifier is to convert the AC input to DC power and supply it
to the inverter. The inverter then converts the DC power to AC power for the load.
The UPS also uses the DC power to charge the batteries as well; a very efficient
method of charging.
SCR
CAPACITOR
DC
OUTPUT
AC
INPUT
RECTIFIER
BREAKERINDUCTOR
6 PULSE FULL CONTROL RECTIFIER
The 10KVA to 60KVA UPS use 6-pulse fully controlled rectification. An inductor is
added before the rectifier to improve the power factor, smooth the current waveform
and eliminate the harmonic current. The control circuit regulates the DC bus within
1%. Soft walk-in circuitry (approximately 20sec.) and current limit circuitry is
used to prevent over current or instantaneous surge current.
Extra under-voltage and over-voltage protections are added to improve reliability and
to shutdown the rectifier in case of abnormal conditions. The DC bus is adjustable to
fit different types of batteries. The power component used in the rectifier is specially
selected to handle extreme high voltage and high current. The rectifier is designed to
operate under a wide range of AC input. The UPS will operate from 384 to 552
VAC and under poor power conditions found in some areas.